10.59987/ads/2013.3-4.218-229
Aim. The primary aim of the present study was to validate the effectiveness of a personalized device able to guide periodontal probing in evaluation of second molar periodontal healing after adjacent third molar surgical extraction. Secondarily, the study analyzed if any patient and tooth related factors affected the second molar periodontal healing as well as if they were able to affect the periodontal probing depth performed with or without the personalized device.
Materials and methods. Thirty-five lower second molars were evaluated after extraction of the adjacent third molar. Pre-operative as well as 3 and 12 month post-operative probing depths of the distal surface of the second molar were evaluated. All measurements were taken by two different methods: standard two-point and four-point probing using a personalized onlay-type guide. Periapical radiographs were also evaluated. The Pearson product moment and the general linear model with backward stepwise procedure were used for inferential statistics.
Results. The mean 12-month post-operative probing depth/mean pre-operative probing depth ratio obtained with the guided probing method showed a highly significant effect on the 12-month radiographic post-operative/pre-operative radiographic measure ratio. None of the examined patient- or tooth-related factors showed a significant effect on pre-operative/12-month post-operative radiographic measure ratio.
Conclusions. The use of the proposed personalized device seems to provide a more reliable estimate of second molar periodontal healing after adjacent third molar surgical extraction. No patientor tooth-related factors seem to be able to affect either second molar periodontal healing or probing depth measures obtained with or without the personalized device in individuals younger than 25 years old. It can be therefore recommended that lower third molar surgical extraction be performed in young adults.
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Annali di stomatologia
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Effectiveness of a personalized device in the evaluation of mandibular second molar periodontal healing after surgical extraction of adjacent third molar
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Original Article
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2022-08-16
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2023-12-04
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Ann Stomatol (Roma)
R. Pippi 
2013
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Effectiveness of a personalized device in the evaluation of mandibular second molar periodontal healing after surgical extraction of adjacent third molar
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1_Pippi2_Riv Annali 3-4 2013 13/02/14 10:52 Pagina 218




                                                                                                                    Original article



                   Effectiveness of a personalized device in the
                   evaluation of mandibular second molar periodontal
                   healing after surgical extraction of adjacent




                                                                                                                                       li
                   third molar




                                                                                  na
                   Roberto Pippi, MD, DDS                                   mate of second molar periodontal healing after ad-
                                                                            jacent third molar surgical extraction. No patient-




                                                                                io
                                                                            or tooth-related factors seem to be able to affect
                   Department of Oral and Maxillo-facial Sciences,          either second molar periodontal healing or probing
                   “Sapienza” University of Rome, Italy                     depth measures obtained with or without the per-
                                                                            sonalized device in individuals younger than 25




                                                                             az
                                                                            years old. It can be therefore recommended that
                   Corresponding author:                                    lower third molar surgical extraction be performed
                   Roberto Pippi                                            in young adults.
                   Department of Oral and Maxillo-facial Sciences




                                                                          rn
                   “Sapienza” University of Rome                            Key words: periodontal healing, periodontal probing,
                   Via Caserta, 6                                           radiographic measurements, smoking, statistics.
                   00161 Rome, Italy
                   Phone: +390649976651




                                                                       te
                   Fax: +390644230811                                       Introduction
                   E-mail: roberto.pippi@uniroma1.it
                                                                            Many studies have been performed over the years to

                   Summary
                                                                    In      verify periodontal modifications of the lower second
                                                                            molar distal surface after adjacent third molar surgical
                                                                            extraction (1-14) with regard to several risk factors,
                   Aim. The primary aim of the present study was to         such as flap design, the infra-bony pre-operative pocket
                   validate the effectiveness of a personalized device      on the second molar distal surface, the patient’s age,
                                                         ni
                   able to guide periodontal probing in evaluation of       the width of the contact area between second and third
                   second molar periodontal healing after adjacent          molar and the mesial width of third molar follicular
                   third molar surgical extraction. Secondarily, the        space. However, clinical evaluation of periodontal de-
                   study analyzed if any patient and tooth related fac-     fects on the distal surface of the lower second molar
                                          o

                   tors affected the second molar periodontal healing       can be affected by non-repeatability of the measure-
                   as well as if they were able to affect the periodontal   ments due to unavoidable variation in the probing site,
                                      izi


                   probing depth performed with or without the per-         as well as of the insertion axis of the periodontal probe.
                   sonalized device.                                        The use of a device to guide periodontal probing theo-
                   Materials and methods. Thirty-five lower second          retically minimizes inter- and intra-examiner variability,
                   molars were evaluated after extraction of the adja-      making the measurements obtained at different times
                         Ed




                   cent third molar. Pre-operative as well as 3 and 12      comparable. The primary aim of the present study was
                   month post-operative probing depths of the distal        to validate the effectiveness of a personalized device
                   surface of the second molar were evaluated. All          built to guide periodontal probing in the clinical evalua-
                   measurements were taken by two different meth-           tion of lower second molar periodontal healing after ad-
                   ods: standard two-point and four-point probing us-       jacent third molar surgical extraction, in comparison
                   ing a personalized onlay-type guide. Periapical radi-    with the conventional periodontal probing technique,
               C




                   ographs were also evaluated. The Pearson product         using the radiographic assessment of bone healing as
                   moment and the general linear model with back-           an objective reference. Second, this study analyzed
    CI




                   ward stepwise procedure were used for inferential        whether any patient- or tooth-related factors were able
                   statistics.                                              to affect second molar periodontal healing, as well as
                   Results. The mean 12-month post-operative prob-          periodontal probing depth performed with or without the
                   ing depth/mean pre-operative probing depth ratio         personalized device.
                   obtained with the guided probing method showed a
                   highly significant effect on the 12-month radi-
©




                   ographic post-operative/pre-operative radiographic       Materials and methods
                   measure ratio. None of the examined patient- or
                   tooth-related factors showed a significant effect on     Sampling
                   pre-operative/12-month post-operative radiographic
                   measure ratio.                                           The examined sample included 35 second molars that
                   Conclusions. The use of the proposed personal-           were clinically and radiographically evaluated before
                   ized device seems to provide a more reliable esti-       and after extraction of the adjacent third molar, from 30

                   218                                                                      Annali di Stomatologia 2013; IV (3-4): 218-229
1_Pippi2_Riv Annali 3-4 2013 13/02/14 10:52 Pagina 219




                   Healing after third molar surgery


                   subjects among the patients treated with the same com-
                   mon protocol by the same operator over a 2-year period
                   at the Oral Surgery Unit of the Department of Oral and
                   Maxillo Facial Sciences at the “Sapienza” University of
                   Rome. The inclusion criteria included the following: at




                                                                                                                                           li
                   least one lower extracted third molar; vertical, mesio-an-
                   gular or horizontal third molar class B-depth impaction;




                                                                                      na
                   the presence of the first two molars and the second pre-
                   molar on the extraction side, to assure stent stability
                   during measurements; and the patient’s consent to use
                   the clinical data for statistical evaluation. The exclusion




                                                                                    io
                   criteria included the following: any systemic disease and
                   local or generalized periodontitis; pregnancy or lacta-
                   tion; any medication in the last 6 months that could influ-
                   ence wound healing after surgery; any type of recon-           Figure 1. The personalized acrylic stent used for the study




                                                                                 az
                   struction on the distal surface of the second molar, as        with the probe positioned in one of the four 6 mm high
                   well as a second molar prosthetic crown on the extrac-         grooves.
                   tion side; caries on the occlusal and inter-proximal sur-
                   faces of the first two molars, as well as on the second




                                                                              rn
                   premolar; a history of root planing performed immediate-       stent at the level of the four points chosen for probing,
                   ly after surgical extraction; a history of problems in stent   using a probe similar to that used for the measure-
                   seating at the 3- and 12-month probing follow-ups; miss-       ments. Each stent was approximately 2 mm thick, in-




                                                                           te
                   ing or incomplete periodontal data or radiographs; any         volved three teeth from the second molar to the second
                   type of conservative or prosthetic rehabilitation per-         premolar and extended for 4-5 mm from the occlusal
                   formed on the molars or second premolar on the extrac-         surface on the distal face of the second molar, ending
                   tion side before the 12-month follow-up; and a history of      approximately 4 mm coronally from the gingival margin,
                   professional calculus or plaque removal after surgery
                                                                        In
                   before the 12-month follow-up. All of the clinical and ra-
                                                                                  so the grooves were at least 6 mm in height. A slight
                                                                                  overlap (approximately 1 mm) of the stent on the lateral
                   diographic measurements were obtained under magnifi-           surfaces of all of the teeth involved was allowed to as-
                   cation using a Head-Worn Loupe KS (Carl Zeiss, Ger-            sure retention and stability.
                   many) with the following technical features: magnifica-        All of the probing measurements were obtained to the
                                                             ni
                   tion ratio: 4x; working distance: 300 mm; free distance        nearest millimeter from the free gingival margin to the
                   to object: 220 mm; field of view: 50 mm; and length of         bottom of the pocket, using the same probe. To im-
                   optical system: 51.5 mm.                                       prove visibility, the measurements were obtained in an
                   All of the following examinations and treatments were          indirect manner, using a #5 mouth mirror (Kerr Co.
                                              o

                   performed by the same investigator.                            USA) positioned distally to the second molar.
                                          izi



                   Periodontal examinations and measurements                      Radiographic examinations and measurements

                   - WHO periodontal screening and recording (PSR), with          - Periapical radiographs were performed pre-operative-
                           Ed




                   a PCP 11 5B probe (Hu-Friedy, USA), and furcation              ly, as well as at 3 and 12 months post-operatively (Fig.
                   probing of first and second molars, with a #2 Nybers           2), with a Castellini radiographic machine (70 KVp – 8
                   probe (PQ2N6 - Hu-Friedy, USA), were performed to              mA – 0.38 kW tube type Cox 70G8CEI), using the par-
                   exclude generalized periodontitis or localized periodon-       allel technique, with a long cone and a precision device
                   titis on the extraction side.                                  (Rinn® XCP Instruments Kit, Dentsply, Elgin, IL, USA)
                   - Periodontal probing depth (PD) of the distal surface of      and a focal object distance of approximately 20 cm. Be-
               C




                   the lower second molar was always performed with the           fore the film-holder was positioned in the mouth, for
                   same straight, tapered, 15 mm probe (42-746-02 2A              each radiograph, a millimetric adhesive grid (Phil x-Ray
    CI




                   Martin, Germany) pre-operatively, as well as at 3 and          Grid - Pat. Pending) was applied on the film side facing
                   12 months post-operatively, on the extraction side by          the teeth. The radiographs were examined on a di-
                   two different methods:                                         aphanoscope (230 V, ~ 50-60 Hz, 85 W - Titanox,
                   A - standard (stand) two-point probing, disto-buccal           Italy). Study measurements were obtained with a milli-
                   (DB) and disto-lingual (DL); and                               metric ruler, from the cement-enamel junction (CEJ) to
                   B - four-point probing (dev), buccal (B), disto-buccal         the bottom of the radiographically detectable bone de-
©




                   (DB), centro-distal (CD) and disto-lingual (DL), using a       fect just near the distal surface of the second molar.
                   personalized onlay-type guide or stent (Fig. 1), directly      For each radiograph, the definitive unknown measure-
                   made in the patient’s mouth during a preliminary ses-          ment was calculated by applying a mathematical pro-
                   sion using auto-polymerizing acrylic resin (Jet Kit, Lang      portion, in which the known terms were the actual milli-
                   Dental MFG Co. Inc. Wheeling, IL, USA) and then com-           metric length of ten vertically contiguous squares of the
                   pleted in the laboratory. During resin polymerization, 4       grid and the millimetric value of the defect, both ob-
                   vertical grooves were made on the distal side of the           tained from the radiographs. Each value obtained in

                   Annali di Stomatologia 2013; IV (3-4): 218-229                                                                        219
1_Pippi2_Riv Annali 3-4 2013 13/02/14 10:52 Pagina 220




                   R. Pippi




                                                                                                                                              li
                                                                                      na
                                                                                    io
                   Figure 2. The complete three-radiograph set of one of the studied second molars. Pre-operative x-ray (left); 3-month post-
                   operative x-ray (middle); 12-month post-operative x-ray (right).




                                                                                 az
                   this manner was then approximated to the nearest milli-        trend index, the standard error (SE), as the variability
                   metric unit. All of the radiographic measurements were         index, and the Kolmogorov-Smirnov test (K-S), as the
                   performed by the examiner at the end of the study.             distribution normality test, were used for descriptive sta-
                   - The following data resulting from pre-operative              tistics of quantitative variables. Absolute and percent-




                                                                              rn
                   panoramic radiographs of all of the patients were also         age frequencies were used for qualitative variables.
                   considered: contact area width between the third and           Pearson’s product moment (r) and the general linear
                   second molar (≤ 3 mm / ≥ 4 mm); and third molar incli-         model (GLM) with the backward stepwise procedure




                                                                           te
                   nation (0-29°/30-59°/60-90°).                                  (BSP) were used for inferential statistics.
                                                                                  The study was conducted with the approval of the local
                                                                                  Ethical Committee, with protocol number 725/12. Ethi-
                   Surgical technique                                             cal principles for medical research, as stated by the

                   Third molar extraction was performed according to the
                                                                        In        Helsinki Declaration, were followed. Informed
                                                                                  consent/assent was obtained from all of the study par-
                   following standard protocol: pre-operative oral antibiotic     ticipants.
                   prophylaxis with amoxicillin plus clavulanic acid (2 g) 1
                   hour before the procedure; 3% mepivacaine anesthesia
                                                          ni
                   of the inferior alveolar nerve, plus 2% mepivacaine infil-     Study design
                   trative anesthesia with adrenaline in the buccal mucosa
                   of the third molar region; angular flap; tooth removal af-     For each of the proposed aims, a different study design
                   ter ostectomy and/or tooth sectioning, if needed; re-          was planned.
                                            o

                   moval of follicular remnants and inflammatory tissue           The first aim was to verify the degree of correspon-
                   from the residual cavity; final cleaning with sterile saline   dence between the periodontal healing evaluation per-
                                        izi


                   irrigation; 3-0 silk sutures with a taper-cut needle; and      formed by radiographic measurements and the probing
                   granular nimesulide 100 mg immediately after surgery           depths measured with and without the personalized de-
                   and further doses, if needed, every 12 hours following         vice as a guide.
                   suture removal at 1 week post-operatively. No root             As a first step, to evaluate the possible improve-
                          Ed




                   planing of the distal surface of the second molar was          ment/worsening over time of the second molar peri-
                   performed before, during or after surgery. No specific         odontal status, the mean pre-operative PD/post-oper-
                   instructions on oral hygiene were provided to the pa-          ative mean PD at 3 and 12 months, as a ratio mea-
                   tients after surgery. Surgical extractions in the same         sured with (dev3/pre and dev12/pre) and without
                   patient were performed at different times.                     (stand3/pre and stand12/pre) the personalized device,
                                                                                  were calculated, in which 1 indicated stableness, val-
               C




                                                                                  ues < 1 indicated improvement, and values > 1 indi-
                   Other clinical features                                        cated worsening. Moreover, the ratios of measure-
    CI




                                                                                  ments obtained from pre-operative radiographs (xrpre)
                   The following data were also collected as binary vari-         to those obtained from 3- (xr3) and 12- (xr12) month
                   ables (yes/no): pre-operative inflammatory signs or            post-operative radiographs were calculated (xr3/pre
                   symptoms; third molar communication with the oral en-          and xr12/pre, respectively) as an objective control.
                   vironment; visible plaque presence on the distal surface       The postulate was that if the probing depth measure-
                   of the second molar at least in one of the follow-up ex-       ments obtained with the personalized device provided
©




                   aminations; and the patient’s smoking habits.                  an effective measurement of the second molar peri-
                                                                                  odontal improvement/worsening, then a statistically sig-
                                                                                  nificant correlation would exist between those measure-
                   Statistical methods                                            ments and the radiographic measurements. In other
                                                                                  words, it should be possible to predict the radiographic
                   Each lower second molar was considered an indepen-             outcome from the probing depth measurements ob-
                   dent statistical unit. The mean value, as the central          tained using the personalized device. Moreover, if the

                   220                                                                             Annali di Stomatologia 2013; IV (3-4): 218-229
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                   Healing after third molar surgery


                   latter were more reliable than the results obtained with     observed values of the dependent variable (xr12/pre)
                   the standard probing method, one might expect that the       and the predicted values on the basis of the explanato-
                   correlation between the measurements obtained with           ry variables (dev12/pre or stand12/pre). The postulate
                   the personalized device and the radiographic measure-        was therefore that, if a variable positively or negatively
                   ments would be stronger than the correlation between         influenced the correlation between xr12/pre and




                                                                                                                                        li
                   measurements obtained with the classic probing               dev12/pre or stand12/pre, that variable should also
                   method and the radiographic measurements. Because            positively or negatively influence the deviation values of




                                                                                    na
                   a very strong correlation was found between dev12/pre        the two xr12/pre models, respectively developed with
                   and dev3/pre (r = 0.91), as well as between                  dev12/pre (xrdev12/preRES) and stand12/pre (xr-
                   stand12/pre and stand3/pre (r = 0.81), meaning that the      stand12/preRES) as explanatory variables. Two differ-
                   second molars, the periodontal status of which im-           ent GLMs with BSP were used to test, respectively the




                                                                                  io
                   proved after 12 months, were basically the same as           effects on xrdev12RES and xrstand12RES of the
                   those found to have improved periodontally after 3           above-mentioned variables: patient’s age, sex, and
                   months, only the ratios calculated at 12 months were         smoking habits (yes/no); visible plaque presence at fol-
                   used (dev12/pre; stand12/pre; xr12/pre) to shorten and       low-up examinations (yes/no); contact area between




                                                                               az
                   simplify the subsequent analysis.                            third and second molars (≤3 mm/≥4 mm); third molar in-
                   Two GLMs were therefore developed: the first one             clination relative to the second molar axis (≤30°/>30°);
                   used xr12/pre as a dependent variable and dev12/pre          pre-operative local signs and/or symptoms of infection
                   as an explanatory variable; the second one, in which         (yes/no); and pre-operative third molar communication




                                                                            rn
                   xr12/pre was used as a dependent variable and                with oral environments (yes/no).
                   stand12/pre as an explanatory variable, was then de-
                   veloped.
                                                                                Results




                                                                         te
                   To investigate more closely the comparison between
                   the standard and guided probing methods, the previous
                   analysis was repeated using the PD measurements ob-          Descriptive results
                   tained in the only comparable point of the two methods,

                   dard method, instead of the mean measurements ob-
                                                                      In
                   named “B” in the guided method and “DB” in the stan-         All of the surgical procedures were uneventful. The age
                                                                                of the patients at the time of surgery ranged from 16 to
                   tained with each of the two methods. Hence, the ratios       46 years old, with a mean age of 24.37 ± 0.93 years
                   between the 12-month post-operative PD and the pre-          old. Nineteen of the 35 third molar extractions were
                   operative PD, respectively obtained with and without         performed in female patients (54.29%) and 16 in male
                                                             ni
                   the stent (B12/pre and DB12/pre), were used. Two fur-        patients (45.71%). Pre-operative symptoms, as well as
                   ther GLMs were therefore developed, using xr12/pre,          communication with the oral environment, were present
                   as a dependent variable and, respectively, B12/pre and       in 19 of 35 cases (54.29%). In 18 of 35 cases
                   DB12/pre as explanatory variables.                           (51.43%), third molar inclination was less than 30°, and
                                              o

                   The second aim was to verify whether and which pa-           in 23 cases (65.71%), the contact area between the
                   tient-related and third molar-related variables influ-       second and third molar was ≥ 4 mm. Twenty-three ex-
                                          izi


                   enced periodontal second molar healing.                      tractions were performed in smokers (65.71%), and in
                   Radiographic measurements after 12 months (xr12/pre)         24 of 35 cases (80%), visible plaque was detectable on
                   have been used as objective measurements of second           the distal surface of the second molar in at least one of
                   molar periodontal healing. A GLM with the BSP (p >           the follow-up examinations.
                           Ed




                   0.05) has been used to analyze the effects of the fol-       The mean probing depths detected pre-operatively
                   lowing explanatory variables on xr12/pre: patient’s age,     (pre), as well as at three (3) and twelve (12) months
                   sex, and smoking habits (yes/no); visible plaque pres-       post-operatively with (dev) and without (stand) the per-
                   ence at follow-up examinations (yes/no); contact area        sonalized device, were the following: devpre=3.10 ±
                   between the third and second molars (≤3 mm/≥4 mm);           0.16; dev3=3.08 ± 0.10; dev12=2.75 ± 0.11; stand-
                   pre-operative local signs and/or symptoms of infection       pre=5.50 ± 0.27; stand3=4.94 ± 0.25; and
               C




                   (yes/no); pre-operative third molar communication with       stand12=4.00 ± 0.16.
                   oral environments (yes/no); and third molar inclination      The mean radiographic measurements of bone defects
    CI




                   relative to the second molar axis (≤30°/>30°). For con-      were the following: pre-operative (xrpre)=6 ± 0.38; 3
                   venience, third molar inclination was also considered a      months post-operatively (xr3)=4.94 ± 0.40; and 12
                   binary variable because only 5 third molars were found       months post-operatively (xr12)=3.68 ± 0.32.
                   to have inclinations between 30° and 60°.
                   The third aim was to verify whether and which patient-
                   related and third molar-related factors influenced the       Inferential analysis results
©




                   correlation between guided probing depths (dev12/pre)
                   and radiographic measurements (xr12/pre) and to de-          First aim
                   termine whether any correlation existed between stan-
                   dard probing depths and radiographic measurements.           The results obtained with the first GLM (Fig. 3) (coeffi-
                   For this type of analysis, the residuals of the two gener-   cient ± SE=0.52 ± 0.15; t=3.56; p=0.0011) showed that
                   al linear models, developed to accomplish the first aim,     dev12/pre had a highly significant effect on xr12/pr (F1,
                   were used. Residuals are the deviations between the          33=12.68; p=0.0011), although the correlation between


                   Annali di Stomatologia 2013; IV (3-4): 218-229                                                                     221
1_Pippi2_Riv Annali 3-4 2013 13/02/14 10:52 Pagina 222




                   R. Pippi




                                                                                                                                             li
                                                                                      na
                                                                                    io
                                                                                 az
                   Figure 3. Ratio of the 12-month post-operative radiograph-     Figure 4. Ratio of the 12-month post-operative radiograph-
                   ic measures to the pre-operative radiographic measures         ic measures to the pre-operative radiographic measures
                   versus ratio of the mean 12-month guided probing depths        versus ratio of the mean 12-month standard probing




                                                                              rn
                   to the mean pre-operative guided probing depths.               depths to the mean pre-operative standard probing depths.


                   the observed xr12/pre values and the predicted values,




                                                                           te
                   on the basis of dev12/pre, was moderate (R=0.53), in-
                   dicating that dev12/pre variability explained a moderate
                   portion of xr12/pre variability. Finally, the residuals (the
                   differences between the observed xr12/pre values and
                                                                        In
                   the predicted values on the basis of dev12/pre) showed
                   an almost normal distribution (K-S: d=0.11; p>0.20).
                   This finding confirms the estimate of the standard error
                   regression coefficient. In other words, a statistically sig-
                   nificant, although moderate, correspondence existed
                                                                ni
                   between radiographic measurements and periodontal
                   probing depth obtained with the personalized device.
                   Results from the second GLM (Fig. 4) (coefficient ±
                   SE=0.65 ± 0.25; t=2.63; p=0.01) were generally similar
                                              o

                   to those obtained with the previous GLM (F1, 33=6.92;
                   p=0.0128), although stand12/pre had a less significant         Figure 5. Ratio of the 12-month post-operative radiograph-
                                          izi


                   effect on xr12/pre than dev12/pre (higher p value), and        ic measures to the pre-operative radiographic measures
                   it explained a smaller portion of xr12/pre than                versus ratio of the 12-month guided probing depths in the
                   dev12/pre (lower R value). In other words, this corre-         B point to the pre-operative guided probing depths at the
                   spondence was lower than that between radiographic             same point.
                           Ed




                   measurements and measurements obtained with the
                   guided probing technique. The use of the personalized
                   device therefore seemed to provide a more reliable es-
                   timate of second molar periodontal healing.
                   The results from the last two GLMs (Fig. 5: F 1,
                   33=12,79; p=0.0011; Fig. 6: F1, 33=7.72; p=0.0089) con-
               C




                   firmed those obtained with the two previous GLMs
                   (Figs. 3, 4), in that the guided method produced find-
    CI




                   ings were slightly more correlated with the radiographic
                   findings (coefficient ± SE=0.42 ± 0.19; t=3.58; p=0.001)
                   than those obtained with the standard method (coeffi-
                   cient ± SE=0.50 ± 0.18; t=2.79; p=0.009).
©




                   Second aim

                   Because no models were developed by the BSP, none              Figure 6. Ratio of the 12-month post-operative radiograph-
                   of the examined patient-and tooth-related factors had          ic measures to the pre-operative radiographic measures
                   significant effects (Tab. 1) (p-values < 0.05 with the T-      versus ratio of the 12-month guided probing depths in the
                   test) on the ratio between pre-operative and 12-month          DB point to the pre-operative guided probing depths at the
                   post-operative radiographic measurements (xr12/pre).           same point.

                   Annali di stomatologia 2013; IV (3-4): 0-0                                     Annali di Stomatologia 2013; IV (3-4): 218-229
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                   Healing after third molar surgery


                   Table 1. Partial correlations (PC) between the explanatory        ferent times. The use of each lower second molar of
                   variables not included in the general linear model and            the same patient as a single statistical unit has already
                   xr12/pre (dependent variable).                                    been reported in previous studies (5-7) because, from
                                                                                     the analysis of variance concerning probing depths and
                   Explanatory variables                PC            T        p     intra-bony defects, it seemed there was no dependence




                                                                                                                                             li
                   Gender                             -0.084        -0.486   0.630   between two operations performed in the same patient,
                   Smoking habits                     -0.022        -0.129   0.898   even if performed at different times.




                                                                                           na
                   Plaque                              0.109         0.630   0.533   The mean age of the patients in the present study
                   Contact area                       -0.194        -1.135   0.264   (24,30 ± 0,98) was younger than that in previous stud-
                   Symptoms                            0.085         0.490   0.627   ies (27,2 ± 6,35 (3); 27 ± 7 (10); 30, 37 ± 2,32) (14). If
                   Inclination                        -0.192        -1.125   0.269   the only patient older than 30 years old (46 years old)




                                                                                         io
                   Communication with oral cavity      0.000         0.002   0.998   was excluded, the mean age of the patients (23,63 ±
                   Age                                 0.137         0.797   0.431   0,73) was similar to that in Montero and Mazzaglia’s
                                                                                     study (13). In the studies of Cetinkaya et al. (11) and
                                                                                     Faria et al. (14) the mean age (18,53 ± 1,60 (11); 21,03




                                                                                      az
                   Table 2. Partial correlations (PC) between the explanatory        ± 4,38) (14) was younger than in the present study.
                   variables not included in the general linear model and            Only two previous studies (5, 10) have evaluated the
                   xrdev12/preRES (dependent variable).                              periodontal condition of any other tooth, to assess
                                                                                     whether second molar periodontal involvement was a




                                                                                   rn
                   Explanatory variables                PC            T       p      local problem due to third molar impaction or peri-
                   Gender                          0.155             0.902   0.373   odontitis. Specifically, Kuegelberg (5) examined the
                   Smoking habits                  0.093             0.540   0.592   first mandibular molar, while Kan et al. (10) examined




                                                                                te
                   Plaque                          0.057             0.326   0.747   the entire dentition. To avoid any influence that local
                   Contact area                   -0.077            -0.446   0.658   or generalized periodontitis might have on post-surgi-
                   Symptoms                        0.012             0.069   0.945   cal second molar periodontal healing, the present
                   Inclination                    -0.225            -1.326   0.194   study analyzed patients in whom the WHO PSR,
                   Communication with oral cavity 0.000
                   Age                             0.191
                                                                     0.002
                                                                     1.118
                                                                             In
                                                                             0.998
                                                                             0.272
                                                                                     which was previously applied, excluded any type of
                                                                                     periodontal involvement (not including the second mo-
                                                                                     lar distal surface).
                                                                                     With the same purpose, to avoid any positive or nega-
                   Table 3. Partial correlations (PC) between the explanatory        tive influence on the healing process, in the present
                                                             ni
                   variables not included in the general linear model and xr         study, patients with systemic conditions that might
                   stand12/pre RES (dependent variable).                             have an effect on bone growth and periodontal heal-
                                                                                     ing, such as uncontrolled diabetes mellitus or im-
                   Explanatory variables                PC           T        p      munosuppressive treatments, and participants who
                                              o


                   Gender                          -0.236        -1.397      0.171   were subjected to professional plaque and calculus
                   Smoking habits                  -0.075        -0.432      0.668   removal after surgery, before the 12-month follow-up,
                                          izi


                   Plaque                          0.120         0.694       0.492   or to root planing immediately after surgical extraction
                   Contact area                   -0.212        -1.246       0.222   were excluded from this study. As a routine measure,
                   Symptoms                        0.119         0.688       0.496   calculus removal was gently performed only intra-op-
                   Inclination                    -0.178        -1.039       0.306   eratively, if present. Actually, root planing of the sec-
                           Ed




                   Communication with oral cavity 0.057          0.331       0.743   ond molar distal surface has been found to improve
                   Age                             0.103         0.597       0.554   healing in the presence of pre-existing periodontal im-
                                                                                     pairment (PD > 4 mm); however, it can determine pe-
                                                                                     riodontal deterioration if performed for any indication,
                   Third aim                                                         for example, in subjects with healthy preoperative sec-
                                                                                     ond molar periodontal status (16). Osborne et al. (17)
               C




                   Because no models were developed with the BSP,                    previously found minimal benefits by root planing and
                   none of the examined patient- or tooth-related factors            curetting the second molar in individuals younger than
    CI




                   had significant effects (Tab. 2) (p-values < 0.05 with the        25 years old at the time of third molar removal.
                   t-test) on the ratio between pre-operative and 12-month           Accuracy is especially needed in clinical studies aimed
                   post-operative radiographic measurements (xr12/pre)               to verify differences in the effectiveness of different di-
                   or on the deviations between the observed value of                agnostic or therapeutic procedures, to avoid any possi-
                   xr12/pre and the values predicted on the basis of each            ble sources of error. All of the steps of each procedure
                   considered factor (Tab. 3) (dev12/pre or stand12/pre).            are subject to the risk of error. Inter-examiner and intra-
©




                                                                                     examiner variability is also a clear source of error in
                                                                                     clinical studies.
                   Discussion                                                        Many attempts have been undertaken in the past to
                                                                                     standardize clinical and radiographic methods in
                   In the present study, 35 second molars were examined              studies aimed to evaluate periodontal healing after
                   after adjacent third molar extraction in 30 patients. In 5        different therapeutic procedures. Methodological
                   patients, both lower third molars were extracted at dif-          standardization certainly limits the intra- and inter-ex-

                   Annali di Stomatologia 2013; IV (3-4): 218-229                                                                           223
1_Pippi2_Riv Annali 3-4 2013 13/02/14 10:52 Pagina 224




                   R. Pippi


                   aminer variability. Furthermore, inter-examiner vari-           whereas the loupe was used to magnify the image.
                   ability is clearly avoided if the measurements are ob-          Much better reading was therefore guaranteed.
                   tained by the same examiner.                                    As for probing force, it is usually thought that measure-
                   In the present study, all of the procedures were per-           ments obtained by the same expert investigator are
                   formed by the same expert surgeon, and much effort              comparable to each other or at least that the existing




                                                                                                                                              li
                   was undertaken to apply reproducible methods of in-             differences are diluted among all measurements. Has-
                   vestigation and treatment to limit any possible causes          sel et al. (21) found poor correlation between PD mea-




                                                                                       na
                   of error. Details were provided for all of the steps of the     surements and the probing force applied, so they con-
                   research, although simple, partly self-made and easily          cluded that probing force had only a moderate influ-
                   available methods were used because they are com-               ence on PD measurements and that the probing tech-
                   monly used in daily practice, they do not require exten-        nique was more critical in PD measurement than the




                                                                                     io
                   sive training for use, and they are not uncomfortable for       pressure applied to the probe. Inter and inter-examiner
                   the patients. The only disadvantage was the direct              variability in PD measurements of a same defect is
                   chair-side making of the stent, which was fairly time-          therefore more related to different areas of the defect
                   consuming and which develops heat and an unpleasant             being measured at different times than to the probing




                                                                                  az
                   taste. An indirect technique could otherwise be used,           force applied in different measurements.
                   so the guide could be made on a plaster cast, obtained          Because probe tip diameter and calibration have also
                   from a previous alginate impression, although in this           been considered as further variables able to influence
                   case, direct adaptation in the patient’s mouth was              periodontal probing and because these characteristics




                                                                               rn
                   sometimes necessary nevertheless before its use.                have been found to change from one probe type to an-
                   Although both clinical and radiographic examinations            other, as well as in the same batch of instruments (22),
                   have limitations in measurement accuracy, and many              in the present study, the same probe was always used




                                                                            te
                   attempts have been undertaken in the past to eliminate          for all of the probing measurements, to improve accura-
                   every source of error and to reduce inter- and intra-ex-        cy and reproducibility.
                   aminer variability, they are commonly used in clinical          As for positional error, in the present study, a personal-
                   practice, as well as in research studies.                       ized device was used to guide the probe during mea-
                   In the present study, probing depth was the only prob-
                   ing parameter considered. Clinical attachment level
                                                                         In        surements. The use of a personalized guide or stent
                                                                                   for periodontal probing depth has already been de-
                   (CAL) was not evaluated because the cemento-enamel              scribed in the literature, (1, 2, 18-20, 23, 24) as well as
                   junction (CEJ) was sometimes not visible on the distal          to evaluate lower second molar periodontal healing af-
                   aspect of the second molar due to its sub-gingival loca-        ter adjacent third molar removal (11). However, Watts
                                                           ni
                   tion, and therefore it could not be used as a clinical ref-     (18) reported that, despite the use of the stent to guide
                   erence point. Moreover, the main aim of the present             periodontal probing, the greater source of error in his
                   study was not to obtain a real measurement of the peri-         study was just the position at which the probe was
                   odontal (bone and soft tissue) level but to verify the dif-     placed. Nevertheless, in Watts’s study (18), the guide-
                                            o

                   ferent ability of the two diagnostic clinical methods ap-       lines were marked on the stent with a heated burnish-
                   plied in evaluating periodontal healing under standard-         er, but no information was provided about the diameter
                                        izi


                   ized conditions.                                                or the depth of the grooves or their height. Cetinkaya
                   The landmarks for radiographic measures were the                et al. (11) reported no information about the stent at
                   CEJ and the bottom of the bone defect on the distal             all. In the present study, the grooves were furrowed
                   surface of the second molar.                                    during resin hardening, using a probe similar to that
                          Ed




                                                                                   used for the measurements, and the groove height
                                                                                   was at least 6 mm to guide the probe properly each
                   Probing measurements                                            time into the same position and with the same inclina-
                                                                                   tion, despite possibly aberrant pocket anatomy (25),
                   There are three possible main sources of error related          scanty visibility and limited patient cooperation due to
                   to probing measurements in the second molar region              discomfort or pain caused by gingival inflammation.
               C




                   (18-20): visual, tactile and positional. The first is related   Moreover, to exclude any interference in the correct
                   to the difficulty in visual perception of the probing depth     choice of the axis of probe insertion during groove fur-
    CI




                   on the distal surface of the second molar with the stent        rowing, no cases with reconstructions or prosthetic
                   in place. The second is mainly related to the presence          crowns on second molars were included in the present
                   of a third molar crown or calculus, which can somewhat          study because imperfect distal surfaces might have al-
                   affect the pre-operative probing depth, as well as prob-        tered the anatomic relationship between the distal
                   ing force and probe-tip diameter and calibration. The           tooth surface and the periodontium, giving rise to diffi-
                   third, which the use of the stent was intended to re-           culties in probe insertion and therefore possibly alter-
©




                   duce, is related to the different probing point and incli-      ing probing depth measurements, which could indicate
                   nation from one measurement to another.                         a false periodontal condition.
                   A mirror and a 4x loupe were used in the present study          Despite the use of the personalized device, some de-
                   to improve visibility during probing measurements. The          gree of error is however to be expected. Watts (18)
                   mirror was used not only to look at the reflected image,        previously suggested that changes in probing depth
                   because direct reading was obstructed by the stent, but         over a period of time are merely due to localized ex-
                   also to reflect the light, thus increasing illumination,        aminer error. Because the variation in horizontal

                   224                                                                             Annali di Stomatologia 2013; IV (3-4): 218-229
1_Pippi2_Riv Annali 3-4 2013 13/02/14 10:52 Pagina 225




                   Healing after third molar surgery


                   probing position seems to have been an important er-         Another possible cause of probing error and low repro-
                   ror in all of the studies in which individual sites were     ducibility of measurements was previously found to be
                   analyzed over time (19), the depth and the height of         the depth of sites (19, 25), most likely because the
                   the grooves seemed to be important features to mini-         deeper the pocket was, the higher the risk of positional
                   mize positional differences, making subsequent mea-          changes of the tip of the probe during its penetration




                                                                                                                                       li
                   sures comparable. In the present study, the grooves          was, although the use of the stent theoretically mini-
                   were furrowed during resin hardening, using a probe          mized this type of possible error as well.




                                                                                    na
                   similar to that used in periodontal probing, so they         Finally, the state of periodontal tissues can influence
                   were almost perfectly aligned with the site that was to      PD measurements as well due to different resistance to
                   be probed. If they were furrowed afterward with a            penetration between variously inflamed and healthy tis-
                   cylindrical burr, they could have incorrectly guided         sues, as well as the different responses of patients to




                                                                                  io
                   the probe into the gingival sulcus due to a wrong in-        probe penetration at various degrees of inflammation.
                   clination. Moreover, the grooves ended approximately         The use of the stent also avoids that the probe insertion
                   4 mm coronally to the gingival margin, so the probe          axis having to be modified relative to the lower compli-
                   was clearly visible during insertion. Nevertheless,          ance of the patient due to possible tissue inflammation.




                                                                               az
                   slight inclination of the probe is possible despite the
                   height of the grooves, which was approximately 6
                   mm, as well as their depth, which was slightly greater       Radiographic measurements
                   than the probe diameter, especially in subsequent




                                                                            rn
                   measurements, because the tapered morphology of              The choice to use the radiographic measurements of
                   the probe does not allow the probe diameter to fit the       bone defects as objective references might be ques-
                   groove diameter in cases of PD less than the pre-sur-        tionable; however, it is a safe and universally recog-




                                                                         te
                   gical PD, so attention was always paid to assure that        nized method to obtain subsequent comparable mea-
                   the probe was in the groove for the entire 6 mm tract        surements of the bone height in a standardized man-
                   during the measurement. A parallel-sided probe could         ner, without surgical re-entry or traumatic periodontal
                   therefore be more adequate in guided probing than a          probing (4). However, many sources of technical radi-
                                                                      In
                   tapered one, although this type of probe is less fre-
                   quently used in clinical practice because it is less
                                                                                ographic errors exist, including vertical or/and horizon-
                                                                                tal changes in projection geometry due to different an-
                   able to penetrate periodontal tissues.                       gulations between the central beam and the film or the
                   Moreover, because it was possible that the stent be-         teeth and different distances between the teeth and
                   came unfit over time and could not be used either due        the film or the tube (4, 26-29). Because intra-oral radi-
                                                             ni
                   to slight tooth movements caused by occlusal forces,         ographic exams provide two-dimensional representa-
                   orthodontics, tooth extraction or periodontal disease or     tions of a three-dimensional condition, in which it can
                   due to conservative or prosthetic tooth rehabilitation       be difficult to distinguish between technical artifacts
                   possibly performed during the study period, patient ex-      and real anatomic changes, a highly standardized
                                              o

                   clusion from the present study was undertaken for            method is necessary to limit inter-exam variability and
                   these reasons. Furthermore, the same stent would             to improve the interpretation of the radiographic
                                          izi


                   most likely be unfit after many years in the case of fur-    anatomy. Actually, a horizontal, abnormal central
                   ther measurements to analyze second molar periodon-          beam angulation can determine superimposition be-
                   tal modification better after adjacent third molar extrac-   tween the tooth root and the bony defect, which can
                   tion over a long period of time, as performed by some        otherwise be obscured by the root (29). Similarly, ab-
                           Ed




                   authors (5, 10).                                             normal vertical angulations can determine false dou-
                   Because bone regeneration is certainly greater where         ble bone levels, with the lingual more or less apical
                   the infra-bony defect is deeper, which is more often in      than the buccal and the bottom of the defect more or
                   the middle of the second molar distal surface due to         less close to the alveolar crest (29).
                   third molar crown impaction, the choice to consider          In the present study, the reproducibility of radiographic
                   four-point measurements with the guided probing              images was always achieved using the long cone par-
               C




                   method, instead of the two line-angle measurements           allel technique, with a precision device and a constant
                   with the standard method, could explain the greater          focal object distance of approximately 20 cm. To make
    CI




                   reliability of the guided method because it might be         the subsequent measurements comparable, patients in
                   able to evaluate the healing process, that is, a site-       whom prosthetic crowns, fillings or inlays/onlays were
                   specific process, in greater detail than the usual           performed on the second molar before the 12-month
                   method. However, because the statistical analysis            follow-up, with possible alteration of the second molar
                   was performed using the mean of the measurements             crown distal surface, were excluded from the study.
                   obtained with each method, the possible greater sen-         Moreover, a millimetric grid was used to measure radi-
©




                   sitivity of the guided method, due to the more detailed      ographic bone defects and to verify the reproducibility
                   evaluation of the infra-bony defects on the distal sur-      of geometric projection. The use of the grid, applied on
                   face of the second molar, could have been diluted.           the film before the radiograph was obtained, is a simple
                   Furthermore, slightly greater reliability of the guided      and cost-effective method from a biological, as well as
                   method was demonstrated, although measurements               an economic, point of view, to minimize errors possibly
                   performed with the two methods only at similar line-         caused by radiographic distortion and enlargement
                   angle points were considered.                                caused by slight differences in film position and/or focal

                   Annali di Stomatologia 2013; IV (3-4): 218-229                                                                     225
1_Pippi2_Riv Annali 3-4 2013 13/02/14 10:52 Pagina 226




                   R. Pippi


                   object distance. However, to the best of the author’s          can also explain both the inter- and intra-examiner vari-
                   knowledge, there have been no studies on periodontal           ability of the method, the guided method compels the
                   healing of the lower second molar distal surface after         probe to penetrate each time at the same point and
                   adjacent third molar extraction but only a report on           with the same inclination. In fact, the probe is an inves-
                   healing after periodontal treatment in which the grid has      tigation instrument, which should be used to freely




                                                                                                                                             li
                   been used (30), and this report showed high accuracy           search the contour of the bone defect and to detect and
                   in bone defect assessment. For radiation hygiene rea-          measure its deepest point. The personalized device




                                                                                      na
                   sons, no second radiographs were obtained at the               used in the present study, as well as some other de-
                   same time to test the image reproducibility of the ap-         vices already proposed in the past, seems to be more
                   plied method. In contrast, because the first radiographs       reliable for comparative research studies, in which the
                   were always of good quality, second radiographs were           definition of the real anatomy of the defect is not an




                                                                                    io
                   never necessary. The reproducibility of radiographic im-       aim, while the free probing method should be prefer-
                   ages has been verified in that the millimetric length of       ably used in clinical practice.
                   ten contiguous squares of the grid, measured on each           The second aspect is the difference between the mean
                   radiograph of the same tooth, was never 0,5 mm                 radiographic measurements and both the guided and




                                                                                 az
                   greater or less than 10 mm, that is, within the approxi-       free probing mean measurements. The present results
                   mation range of periodontal PD measurements. In fact,          are difficult to explain and disagree with those of
                   low levels of variability have already been shown in the       Kuegelberg et al., (4) who found a mean infra-bony in-
                   past in the lower molar region, especially if the parallel     crease of approximately 0.6 mm for every millimeter of




                                                                              rn
                   technique with the long cone was used (4, 26-28, 31,           increased PD, starting from 3 mm of PD and 1 mm of
                   32), regardless of the use of a personalized film-holder,      infra-bony defect and who suggested that the presence
                   applied by means of acrylic resin or impression material       of pseudo-pockets on the distal surface of second mo-




                                                                           te
                   (28, 32), to reproduce the same position of the film           lars explained the discrepancy.
                   each time relative to the teeth and therefore to obtain        Some considerations can help in understanding the
                   super-imposable subsequent dental radiographs.                 present results. Probing depth is a linear measurement,
                   Another source of error in bone defect depth measure-          which employs the free gingival margin as a superficial

                   because of interference from anatomic structures due
                                                                        In
                   ment is difficulty in radiographic CEJ location (31, 32)       reference point and the deepest point of the bone de-
                                                                                  fect as a deep reference point. Periodontal probes cer-
                   to horizontal and/or vertical angulation of the central X-     tainly never reach the latter point, except in intra-opera-
                   ray beam, although the use of the long cone parallel           tive probing or probing at surgical re-entry, although
                   technique seems to result in no significant differences        probing to bone, under local anesthetics, has been pro-
                                                          ni
                   in locating the correct CEJ position when applied in the       posed as a more precise method for obtaining more re-
                   lower molar region. To improve the examiner’s ability to       alistic measurements (33). Some anatomic variables
                   locate the radiographic reference points, in the present       can influence PD measurement: gingival tissue thick-
                   study, measurements were obtained under a 4x magni-            ness; bone defect topography; the presence of obsta-
                                             o

                   fication view. Higher magnifications have already been         cles to probe penetration, such as calculus; and differ-
                   reported to be useless (4).                                    ent consistency and thickness of connective attach-
                                         izi


                   The removal of decimals from the definitive radiograph-        ment, which are also relevant with regard to different
                   ic measurements for statistical analysis, with approxi-        degrees of inflammation.
                   mation to the nearest unit, has already been applied by        The mean pre-surgical measurements found in the pre-
                   Kuegelberg et al., (4) and it can be justified by the limit-   sent study (xrpre: 6 ± 0.38; devpre 3.10 ± 0.16; stand-
                          Ed




                   ed influence that decimals have on final data. More-           pre 5.50 ± 0.27) can be mainly explained by the inter-
                   over, if clinical measurements are related to radi-            ference with probe penetration, possibly due to the third
                   ographic measures, it is plausible that the two types of       molar crown and sometimes due to the calculus, espe-
                   measurements fall in the same range of approximation.          cially in the guided method because it more extensively
                   The possible, although minimal, residual variability of        studied the distal surface of the second molar, and ow-
                   radiographic measurements in the present study,                ing to the stent, it did not allow the probe to avoid ob-
               C




                   caused by all of the above-mentioned sources of error,         stacles during penetration. As for the 3-month mea-
                   was not very important in the present investigation in         surements (xr3 = 4.94 ± 0.40; dev3 = 3.08 ± 0.10;
    CI




                   that each radiographic measurements, used as objec-            stand3 = 4.94 ± 0.25), they can be explained by the re-
                   tive reference of periodontal healing, was related to the      sistance to probe penetration offered by the last 1-3
                   mean PD found at the same time with the two different          mm connective attachment fibers because healing had
                   probing methods applied.                                       occurred by then, and the gingival margin was near fi-
                                                                                  nal maturation. Finally, increased gingival tissue, as
                                                                                  Kuegelberg et al. (4) already suggested, can explain
©




                   Descriptive results                                            the results found in the present study regarding the 12-
                                                                                  month measurements (xr12: 3,68 ± 0,32; dev12: 2,75 ±
                   The first aspect to be analyzed is the difference found        0,11; stand12: 4,00 ± 0,16).
                   between the mean PD measured with the stent and the            The third aspect to be considered is the progression,
                   mean standard PD. One possible explanation for this            over time, of periodontal healing on the distal surface of
                   difference is that, while with the free probing method,        the lower second molar after adjacent third molar ex-
                   the deepest defect point is sought, and this technique         traction. The present results seem to demonstrate pro-

                   226                                                                            Annali di Stomatologia 2013; IV (3-4): 218-229
1_Pippi2_Riv Annali 3-4 2013 13/02/14 10:52 Pagina 227




                   Healing after third molar surgery


                   gressive improvement of soft and hard tissue healing          taken in patients with periodontal disease, in which
                   after surgery. This finding is supported by the results       healing could be impaired either by the older age of pa-
                   reported by the Critically Appraised Topic of Richard-        tients or by the presence of the disease.
                   son and Dodson (16), based on 8 articles they re-             The results of the present study, which did not find cor-
                   viewed, in which PD measurements were found, on av-           relations between any study variable and the healing




                                                                                                                                         li
                   erage, to be unchanged or to have improved 6 to 12            process on the distal surface of the second molar, are
                   months after third molar extraction, although the pre-        in line with those of Kuegelberg et al., (5) who showed




                                                                                     na
                   sent results refer to 3- and 12-month post-operative          that patient sex and age at the time of surgery, the
                   measurements.                                                 presence of visible plaque, bleeding on probing, prob-
                                                                                 ing depths ≥ 7 mm on the distal surface of the second
                                                                                 molar and a widened third molar follicle did not affect




                                                                                   io
                   Inferential results                                           the healing process in individuals younger than 20
                                                                                 years of age, although the present results are not sup-
                   The results from the comparison between periodontal           ported by those of other studies, which found correla-
                   probing measurements with and without the personal-           tions between one or more variables and the healing




                                                                                az
                   ized device with regard to radiographic measures should       process. Montero and Mazzaglia (13) found that third
                   be considered with some caution because the differ-           molar depth was strongly correlated with both baseline
                   ences between the two models are small, and they could        periodontal PD and post-surgical changes. In the study
                   also have been due to random fluctuations. Replication        by Kan et al., (10) detectable plaque at the distal sur-




                                                                             rn
                   of this study will therefore be needed to confirm the ap-     face of the second molar, mesio-angular third molar im-
                   parent greater reliability of the guided probing depth.       paction and the presence of a crestal radiolucency api-
                   Because a low correlation between dev 12/pre and              cal to the third molar were found to be related to peri-




                                                                          te
                   stand 12/pre (r = 0.15) was found, it is also possible        odontal probing depth in the regression model in indi-
                   that the two methods provide complementary and not            viduals just older than 25 years old (27 ± 7). Although it
                   redundant information on second molar periodontal             is plausible that the presence of plaque on the distal
                   healing. Actually, because the healing process occurs         surface of the lower second molar could influence peri-
                   in a progressive but quantitatively non-homogeneous
                                                                       In
                   manner, probing depth at different points could detect
                                                                                 odontal healing after adjacent third molar removal, and
                                                                                 because the distal surface of the second molar has
                   different quantitative aspects of the same process.           been previously found to show a higher plaque score
                   It is also important to emphasize that the results obtained   than other surfaces, this surface could be a locus mi-
                   by the two probing methods were only moderately corre-        noris resistentiae for the development of local periodon-
                                                             ni
                   lated with the results obtained by radiographic measure-      titis, as well as for deterioration of the healing process
                   ments, as already found by Kuegelberg et al. (4). This        (3). However, despite only a few patients have previ-
                   finding is true either if the mean PD obtained from each      ously been found to be plaque-free on this surface,
                   of the two probing techniques was used for statistical        plaque was not found to be related to second molar pe-
                                              o

                   analysis or if the measurements obtained with the two         riodontal healing in patients younger than 20 years old
                   techniques at their only similar point (B and DB) were        (6). To verify whether the presence of plaque did or did
                                          izi


                   used. This low correlation can be explained by consider-      not have an impact on second molar periodontal heal-
                   ing that probing depth and radiographic bone level are        ing, no cases were included in the present study in
                   two aspects of the same periodontal picture, which are        which the patient’s oral hygiene following extraction
                   only partially related to each other. Hausmann et al. (34)    was supervised or enhanced, although it is possible
                           Ed




                   reported that probing attachment level and radiographic       that the two scheduled follow-up examinations never-
                   bone level were different features of periodontitis and       theless positively influenced patient oral health. Howev-
                   that the weak correlation between their respective            er, Kuegelberg et al. (6) already showed that enhanced
                   changes could the result of a number of causes, which         plaque control during the initial phase of healing did not
                   range from no relationship to a time lag, which could ob-     affect the prevalence of intra-bony defects.
                   scure any relationship.                                       No other authors, with the exclusion of Kuegelberg (5),
               C




                   A very weak correlation between probing attachment            who found post-surgical healing impairment due only to
                   changes and radiographic changes over a 2-year peri-          smoking in individuals older than 30 years old, have in-
    CI




                   od was reported by Pilgram et al., (35) who suggested         vestigated the correlation between smoking habits and
                   that although there were some physio-pathologic rea-          lower second molar periodontal healing after adjacent
                   sons to believe that a relationship existed between at-       third molar extraction. The present results seem to dis-
                   tachment level and bone height, this relationship             agree with those of the systematic review by Patel et
                   seemed to be weak, complex and/or not time-related.           al., (38) who found that smoking had a negative effect
                   Another likely reason for the low correlation between         on bone regeneration. However, these authors ana-
©




                   clinical and radiographic measurements is that the            lyzed bone regeneration after regenerative therapies in
                   changes over the 1-year study period were within the          periodontally compromised patients, while in the pre-
                   range of errors with the measuring techniques used, as        sent study, bone regeneration was spontaneous, and
                   already suggested by others (36).                             the patients were younger and were free from peri-
                   Other previous studies (33, 34, 36, 37) have investigat-      odontal disease.
                   ed the correlation between clinical and radiographic as-      Because the non-significant effect of each of the pa-
                   sessments of periodontal healing, but they were under-        tient- or tooth-related examined variables could also

                   Annali di Stomatologia 2013; IV (3-4): 218-229                                                                      227
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                   R. Pippi


                   have been due to the qualitative nature of some of the                      lar 6-36 months after impacted third molar extraction. A ret-
                   variables (e.g., smoking, plaque, etc.), further studies                    rospective cross-sectional study of young adults. J Clin Pe-
                   are needed, in which only quantitative measurements,                        riodontol 2002; 29(11):1004-1011.
                                                                                         11.   Cetinkaya BO, Sumer M, Tutkun F, Sandikci EO, and Misir
                   such as the number of cigarettes smoked, the plaque
                                                                                               F. Influence of different suturing techniques on periodontal
                   amount and the degree of pre-operative infection,




                                                                                                                                                             li
                                                                                               health of the adjacent second molars after extraction of im-
                   and/or an increased sample size should be evaluated                         pacted mandibular third molars. Oral Surg Oral Med Oral
                   to investigate whether one or more of the study vari-




                                                                                            na
                                                                                               Pathol Oral Endod 2009; 108(2):156-161.
                   ables have significant effects on second molar peri-                  12.   Ana F-I, Mercedes G-T. A modified device for intra-oral ra-
                   odontal healing.                                                            diography to assess the distal osseous defects of mandibu-
                                                                                               lar second molar after impacted third molar surgery. Imag-
                                                                                               ing Sci Dent 2011; 41:115-121.




                                                                                          io
                   Conclusions                                                           13.   Montero J, Mazzaglia G. Effect of removing an impacted
                                                                                               mandibular third molar on the periodontal status of the
                                                                                               mandibular second molar. J Oral Maxillofac Surg 2011;
                   In conclusion, within the limits of the present study, a
                                                                                               69:2691-2697.




                                                                                       az
                   personalized device seems to provide a more reliable
                                                                                         14.   Faria AI, Gallas-Torreira, López-Ratón M. Mandibular second
                   estimate than the standard probing method of peri-                          molar periodontal healing after impacted third molar extraction
                   odontal healing on the distal surface of the lower sec-                     in young adults. J Oral Maxillofac Surg 2012; 70:2732- 2741.
                   ond molar after adjacent third molar extraction.                      15.   Krausz AA, Machtei EE, Peled M. Effects of lower third mo-




                                                                                    rn
                   Because all of the examined patient- and tooth-related                      lar extraction on attachment level and alveolar bone height
                   factors seemed to not be able to affect either second                       of the adjacent second molar. Int J Oral Maxillofac Surg 2005;
                   molar periodontal healing or probing depth measure-                         34(7):756-760.
                   ments obtained with or without the proposed personal-                 16.   Richardson DT, Dodson TB. Risk of periodontal defects af-
                                                                                               ter third molar surgery: an exercise in evidence-based clin-




                                                                                 te
                   ized device in individuals younger than 25 years old, it
                                                                                               ical decision-making. Oral Surg Oral Med Oral Pathol Oral
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                                                                                               Radiol Endod 2005; 100(2):133-137.
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