10.59987/ads/2018.3.123-129
Aims: The purpose of this in-vitro research was to compare microhardness and cervical microleakage of healthy and periodontally involved dentin after restoration with conventional and bulk-fill composites.
Methods: For microhardness test, 20 human molars were collected (10 healthy and 10 for periodontal reasons). Dentinal disks from cemento-enamel junction were prepared. Each specimen received 9 indentations (3 for each superficial, median and deep dentin) and an average of them was recorded as the Vickers hardness number (VHN) of each area. For microleakage test, 20 healthy teeth and 20 extracted for the periodontal disease were collected. A standardized box-only cavity was prepared in every tooth. The samples of each group were randomly allocated to two subgroups of 10 and restored as follows: in the experimental group, the cavities were filled by a 4-mm layer of Tetric N-Ceram bulk-fill resin composite (BRC). In the control group, the conventional resin composite (Tetric NCeram) was inserted incrementally and then light cured. After 1000 cycles of thermocycling, cervical microleakage was evaluated by dye extraction technique. Data were submitted to ANOVA, t-test, and Mann-Whitney U test (α = 0.05).
Results: VHN values of healthy dentin at all depths were more than periodontally involved dentin. The most microleakage was seen in periodontally involved teeth filled with conventional composite, but there were no significant differences between different groups.
Conclusions: Although periodontal disease had a significant effect on the reduction of VHN, but no significant effect was observed on the cervical microleakage after using different resin composites.
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Annali di stomatologia
microleakage
Microhardness and cervical microleakage of healthy and periodontally involved dentin at class II cavities restored with conventional and bulk-fill resin composites
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Original Article
2018-09-01
2022-05-19
2018-09-01
2023-12-04
123-129
Ann Stomatol (Roma)
F. Namdar
2018/09/01
10.59987/ads/2018.3.123-129
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microleakage
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Microhardness and cervical microleakage of healthy and periodontally involved dentin at class II cavities restored with conventional and bulk-fill resin composites
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                                                                                                 Original article



    Microhardness and cervical microleakage of healthy
    and periodontally involved dentin at class II cavities
    restored with conventional and bulk-fill resin




                                                                                              li
    composites




                                                                                            na
    Horieh Moosavi1 DDS, MS                                 ed. A standardized box-only cavity was prepared in




                                                                                          io
    Sara Majidinia2 DDS, MS                                 every tooth. The samples of each group were ran-
    Seyed Ali Banihashem Rad3 DDS, MS                       domly allocated to two subgroups of 10 and re-
    Mohammad Jafari Giv4 DDS                                stored as follows: in the experimental group, the
    Fatemeh Namdar5 DDS, MS




                                                                      az
                                                            cavities were filled by a 4-mm layer of Tetric N-Cer-
                                                            am bulk-fill resin composite (BRC). In the control
                                                            group, the conventional resin composite (Tetric N-
    1 Associate Professor, Department of Restorative and    Ceram) was inserted incrementally and then light
    Cosmetic Dentistry, School of Dentistry, Mashhad Uni-   cured. After 1000 cycles of thermocycling, cervical




                                                                    rn
    versity of Medical Sciences, Mashhad, Iran              microleakage was evaluated by dye extraction tech-
    2 Assistent Professor, Department of Restorative and    nique. Data were submitted to ANOVA, t-test, and
    Cosmetic Dentistry, School of Dentistry, Mashhad Uni-   Mann-Whitney U test (α = 0.05).




                                                     te
    versity of Medical Sciences, Mashhad, Iran              Results: VHN values of healthy dentin at all depths
    3Associate Professor, Department of Periodontics,       were more than periodontally involved dentin. The
    School of Dentistry, Mashhad University of Medical      most microleakage was seen in periodontally in-
    Sciences, Mashhad, Iran
                                                   In
    4 Dentist, Dental Research Center, Mashhad University
                                                            volved teeth filled with conventional composite, but
                                                            there were no significant differences between dif-
    of Medical Sciences, Mashhad, Iran                      ferent groups.
    5 Assistant Professor, Dental Materials Research Cen-   Conclusions: Although periodontal disease had a
    ter, Mashhad University of Medical Sciences, Mashhad,   significant effect on the reduction of VHN, but no
                               ni
    Iran                                                    significant effect was observed on the cervical mi-
                                                            croleakage after using different resin composites.
                             io


    Corresponding Author:                                   Key Words: bulk-fill composite, dentin, micro-
    Fatemeh Namdar                                          hardness, microleakage.
    Dental Materials Research Center,
                           iz



    Mashhad University of Medical Sciences
    Vakil-Abad Blvd, Mashhad 91735, Iran                    Introduction
    Tel.: +989155081447
           Ed




    Fax:+985138829500                                       Free radical polymerization of methacrylate-based
    E-mail: F.namdar90@gmail.com;                           resin composites leads to volumetric shrinkage (1)
    namdarf2@mums.ac.ir                                     and defect formation at the interface between tooth
                                                            and restoration, recurrent caries, increased sensitivity
                                                            and cuspal deflection (2). Recently, bulk-fill resin
    Summary                                                 composites (BRCs) have been introduced by en-
 IC




                                                            hanced mechanical properties and time-saving (3).
    Aims: The purpose of this in-vitro research was to      These composites are claimed to be used for incre-
    compare microhardness and cervical microleakage         ments of up to 4 mm thickness, without adverse ef-
    of healthy and periodontally involved dentin after      fects on the degree of conversion (4).
C




    restoration with conventional and bulk-fill compos-     Mechanical and chemical properties of root dentin ex-
    ites.                                                   posed to periodontal disease may present significant
    Methods: For microhardness test, 20 human molars        alterations considering the difference in microbial flo-
    were collected (10 healthy and 10 for periodontal       ra involved in cervical dentin caries and therefore af-
©




    reasons). Dentinal disks from cemento-enamel            fect dentin bond strength in cervical areas (5). Be-
    junction were prepared. Each specimen received 9        cause of the modifications in the tooth structures ex-
    indentations (3 for each superficial, median and        posed to periodontal diseases, the microhardness
    deep dentin) and an average of them was recorded        value is thought to be different between normal and
    as the Vickers hardness number (VHN) of each            periodontal involved dentin.
    area. For microleakage test, 20 healthy teeth and 20    The lack of enamel at the deep gingival margin of
    extracted for the periodontal disease were collect-     class II cavities leads to unstable adhesion of com-

    Annali di Stomatologia 2018;IX (3):123-129                                                                  123
    H. Moosavi et al.


    posite resin to dentin or cementum. Also, dentin has       microhardness. Dentinal discs were obtained just
    less mineralized content and more water when com-          from cemento-enamel junction (CEJ) area with 2 mm
    pared to enamel (6). Furthermore, in the gingival mar-     thickness using a low-speed diamond saw (IsoMet
    gin of class II cavities, polymerization shrinkage and     4000, Buehler, USA) (Fig. 1). After polishing by sili-
    shrinkage stresses may exceed the adhesive-dentin          con paper of 1000, 1500, 2000 grit, Vickers indenta-




                                                                                                   li
    bond strength which leads to gap formation and mi-         tions (Sinowon Manual, China) were performed for
    croleakage (7). Although BRCs have shown low poly-         dentin surfaces (superficial, median and deep) with a




                                                                                                 na
    merization shrinkage and high curing depth, concerns       force of 100 g for 20 s (Fig. 2). Each specimen re-
    are about the ability of these composites to complete-     ceived 9 indentations (3 for each superficial, median
    ly adapt to cervical cavosurface margins and internal      and deep dentin) and an average of the readings of
    surfaces of class II cavities (3).                         each area at different groups was recorded as the
    Previous researches have shown that collagenous            Vickers hardness number (VHN) of a region.




                                                                                               io
    matrix breakdown by Host-derived dentinal matrix
    proteinases following periodontal disease, especially      Microleakage assessment
    chronic periodontitis, can affect the adhesive proper-     As previously stated, forty extracted teeth (20 healthy




                                                                         az
    ties of composite resin to dentin (8-10). Additionally,    and 20 extracted due to severe chronic periodontitis
    due to different microbial flora in periodontal disease,   disease) were used for this test. A standardized box
    mechanical and chemical properties of radicular            only cavity was prepared on the mesial surface of
    dentin exposed to oral cavity can be different from        each tooth with a new fissure diamond (008) bur




                                                                       rn
    healthy dentin and this influences the bond strength       mounted in a high-speed dental handpiece and air
    to cervical dentin. Since the use of bulk-fill compos-     and cooling water spray. The buccolingual extension
    ites are expanding and also the overall age of the         and axial depth of the cavities were 3 mm and 1.5
    community and the presence of cervical lesions fol-




                                                        te
    lowing periodontal diseases are increasing, therefore
    we conducted this laboratory research to evaluate
    whether a bulk filling technique affects gingival mi-
    croleakage in healthy and periodontally involved
                                                      In
    dentin of class II cavities. Null hypotheses of this
    study were: 1) there wouldn’t be any significant differ-
    ence in microhardness of the healthy and periodon-
                             ni
    tally involved dentin; 2) type of dentin (healthy and
    periodontally involved) and composite resin (bulk-fill
    or conventional) wouldn’t influence the cervical mi-
    croleakage of class II cavities.
                           io


    Materials and methods
                         iz



    Sixty extracted, caries-free human permanent molars
    without cracks and restoration (30 healthy human third
           Ed




    molar teeth, 30 ones extracted due to severe chronic
    periodontitis disease) were collected in this study. Ten
    samples of each group were randomly allocated for
    measurement of Vickers microhardness and 20 speci-
    mens for microleakage assessment. After extraction,
    all teeth were stored in thymol solution at 4°C for less
 IC




    than one month. Healthy impacted or semi-impacted
    third molars were obtained by surgery. Also, perma-
    nent molars suffering from severe chronic periodontitis
    with more than 5 mm periodontal pockets were select-
C




    ed from individuals with age 41 to 50 years. After re-
    moving residual periodontal tissues, the specimens
    were cleaned with pumice. An informed consent was
    obtained from donors under the protocol approved by
©




    the Ethics Committee for Human Studies and registry
    no.IR.mums.sd.REC. 1394. 68.

    Measurement of Vickers microhardness
    Twenty extracted teeth (10 healthy human third mo-
    lars and 10 extracted due to severe chronic periodon-
    titis disease) were used for measurement of Vickers        Figure 1. Dentinal discs obtained from CEJ area.


    124                                                                           Annali di Stomatologia 2018;IX (3):123-129
    Periodontally involved teeth and bulk-fill composites


                                                                               am resin composite (Ivoclar vivadent, Schaan, Liecht-
                                                                               enstein) was inserted incrementally in preparations of
                                                                               the control subgroup while the thickness of each layer
                                                                               was approximately 2 mm and photo-activated for 40
                                                                               seconds. Materials’ details and manufacturers’ speci-




                                                                                                                         li
                                                                               fications are shown in Table1.
                                                                               The restored specimens were then subjected to artifi-




                                                                                                                       na
                                                                               cial aging. The samples were immersed in distilled
                                                                               water baths at the temperature of 5°C and 55°C for
                                                                               1000 cycles. The storage period in each temperature
                                                                               was 20 seconds and the transferring period was 10
                                                                               seconds.




                                                                                                                     io
                                                                               Dye extraction technique
                                                                               All restored teeth were covered by two layers of nail




                                                                                            az
                                                                               polish up to one millimeter from the cervical margin
    Figure 2. Cross sectional view of dentin surfaces (a) super-               and then were submerged in methylene blue solution
    ficial, (b) median and (c) deep dentin for evaluation of Vick-             for two days. Subsequently, the root of each speci-
    ers microhardness.                                                         men was cut just a lower level from the penetration




                                                                                          rn
                                                                               area by a diamond saw mounted on the low speed
                                                                               cutting machine (IsoMet, Buehler, USA) (Fig. 3) and
    mm, respectively. The cervical margin was left as a                        the remaining crown was then stored in a bottle con-
    butt joint and located 0.5 mm below the CEJ. All di-




                                                                    te
                                                                               taining 1000 μl of nitric acid (65% by weight) for three
    mensions were checked with the periodontal probe                           days. Then the bottles were centrifuged (Versatile
    and digital caliper to ensure uniformity among prepa-                      SIGMA, Montreal Biotech, Montreal, Quebec, CA) for
    rations. The cavities were prepared uniformly by an                        5 minutes at 14,000 rpm, and 100 μl of every speci-
    expert operator. The dentin and enamel surfaces
                                                                  In           men was evaluated by using the spectrophotometer
    were conditioned with 37.5% phosphoric acid (Ivoclar                       (CECIL Instruments, Cambridge, UK) at 550 nanome-
    Vivadent, Schaan, Liechtenstein) for 30 and 15 sec-                        ter. The spectrophotometer findings indicate the light
    onds, respectively. Rinsing was done for 15 seconds                        absorption of the methylene blue in the interface of
                                  ni
    and the remaining water was eliminated by absorbing                        dentin and resin that present the microleakage score
    cotton. The adhesive Tetric N-Bond (Ivoclar Vivadent,                      of the restoration.
    Schaan, Liechtenstein) was applied based on the
    manufacturer’s instruction and photo-activated for 20
                                io

                                                                               Statistical analysis
    seconds using the light curing device (1200 mW/cm2,                        The differences in hardness measurements were an-
    Bluephase C8, Ivoclar Vivadent, Schaan, Liechten-                          alyzed with two-way ANOVA and Tukey test. Statisti-
    stein). Matrix application was done with Tofflemire
                              iz



                                                                               cal analysis of microleakage was done by indepen-
    stainless steel matrices. Then the samples of each                         dent-samples t-test and Mann-Whitney U test using
    group of healthy and periodontally involved dentin
                                                                               SPSS version 14.0 (Chicago, Illinois, USA). The sig-
    were randomly divided to two subgroups of 10 and
            Ed




                                                                               nificance level was considered 0.05.
    restored as follows:
    In the experimental subgroup, a 4-mm layer of Tetric
    N-Ceram BRC (Ivoclar vivadent, Schaan, Liechten-
                                                                               Results
    stein) was placed into the cavity and packed against
    the metallic matrix and then light activated for 40 sec-
                                                                               Vickers microhardness values
    onds in continuous mode. Conventional Tetric N-Cer-
 IC




                                                                               Average VHN values of healthy dentin at all depths



    Table 1. Materials’ details and manufacturers’ specifications.
C




    Name                            Composition                                                              Filler wt%, vol%
    Tetric N-Ceram                  Dimethacrylates (Bis-GMA, Bis-EMA, UDMA), barium glass,                  80% (including 17%
    Bulk fill                       Ytterbium
                                    itterbium trifluoride, mixed oxide and prepolymer, additives,            prepolymers), 60%
©




                                    catalysts, stabilizers, pigments
    Tetric N-Ceram                  Bis-EMA,UDMA, TEGDMA, Ba-Al-Fl-borosilicat Glass, Ba                     80-81%wt
    Conventional                    Glass, YbF3
    Bis-GMA, Bisphenol-A diglycidyl ether dimethacrylate; Bis-EMA, Bisphenol-A ethoxylated dimethacrylate; TEGDMA, Triethylene glycol dimethacrylate;
    UDMA, urethane dimethacrylate.
    - Prepolymer includes monomer, glass filler and ytterbium fluoride.




    Annali di Stomatologia 2018;IX (3):123-129                                                                                                  125
    H. Moosavi et al.


                                                                                              Figure 3. Representation of the
                                                                                              penetration area after covering
                                                                                              the specimen with two layers of
                                                                                              nail varnish.




                                                                                                       li
                                                                                                     na
                                                                                                   io
                                                                           az
                                                                         rn
                                                              te
                                                            In
                               ni

    Table 2. Comparison of VHN values (Mean±SD) between different depths of dentin.

                              Dentin Type                              VHN                              P-value
                             io


    Superficial               Healthy                                  89.3±19.4b                       0.071
                           iz



                              Periodontally involved                   75.3±11.9a

    Median                    Healthy                                  78.0±18.8a                       0.096
           Ed




                              Periodontally involved                   65.2±12.5c

    Deep                      Healthy                                  78.0±7.9a                        0.288

                              Periodontally involved                   74.7±10.3a

    The same letters indicate no significant differences.
 IC




    were more than periodontally involved dentin, but the        the differences between two resin composites were
C




    differences between them were not statistically signif-      not statistically significant (Fig. 4). Additionally, peri-
    icant (Table 2). VHN values at superficial area of           odontally involved dentin showed higher microleak-
    healthy dentin were more than other depths, but influ-       age scores compared to healthy dentin but statistical
    ences of dentin depth were not statistically signifi-        analysis presented no significant differences between
©




    cant. In periodontally involved teeth, superficial and       two groups.
    deep dentin showed the same microhardness values.

    Microleakage assessment                                      Discussion
    However cervical microleakage scores of convention-
    al resin composite bonded to both healthy and peri-          The results of this research showed that the VHN val-
    odontally involved dentin were more than BRC, but            ues of superficially dentin were significantly higher


    126                                                                               Annali di Stomatologia 2018;IX (3):123-129
    Periodontally involved teeth and bulk-fill composites




                                                                                                       li
                                                                                                     na
                                                                                                   io
                                                                              az
                                                                            rn
                                                              te
                                                            In
    Figure 4. Cervical microleakage of two resin composites (conventional and bulk fill) at healthy and periodontally involved
    dentin.

    than median and deep healthy dentin. Previous stud-            with exposure of cementum (17, 18). They presented
    ies have shown that the microhardness values of                that the microhardness values had reverse relation-
                               ni
    dentin must be demonstrated in terms of the region in          ship with periodontal pocket depth (17, 18). Lee et al.
    dentin. Some studies have reported that the superfi-           showed that the host-activated dentin proteinases
    cial dentin was harder than the inner dentin and the           causes the destruction of collagen matrix following
                             io


    hardness decreased from the dentino-enamel junc-               periodontal disease and may reduce the dentin hard-
    tion (DEJ) to the pulp (11, 12). Kinney et al. demon-          ness of periodontally involved teeth (10).
    strated that the hardness reduction as a function of           The results of this study validated the second re-
                           iz



    depth was related to the lower stiffness of inter-tubu-        search hypothesis, as there were not any significant
    lar dentin because of non-homogeneous distribution             differences in cervical microleakage of class II cavi-
    of the inorganic content within the organic matrix             ties concerning the type of dentin (healthy or peri-
           Ed




    (12). Pashley et al. reported that the enhanced tubu-          odontally involved teeth) and placement techniques
    lar density at interior dentin corresponded to de-             (bulk-fill or incrementally). Least cervical microleak-
    creased hardness (13). Another study stated that               age was also observed at healthy dentin of class II
    hardness reduction with the location might be related          cavities filled with Balk-fill resin composite.
    to differences in the hardness of intertubular dentin,         Polymerization shrinkage and contraction stress can
    not to more quantity of tubules (14). Fuentes et al.           induce adhesive failure and gap formation in the com-
 IC




    (11) reported VHN=63 for deep sound dentin and                 posite restorations. Also, placement technique, pho-
    stated since that the dentin tubules are not oriented          to-activation method, stress relieving capacity and C-
    randomly, properties may depend on their direction.            factor are effective on the magnitude of the stress (4).
    The mean VHN scores reported in this study for                 El-Damanhoury et al. showed a significant reduction
C




    healthy dentin were in ranging from 78 to 89.3 and             in shrinkage stress of BRC compared to conventional
    were somewhat higher than previous studies (57-62              resin composites while maintaining the depth of cur-
    VHN). The dissimilarity between reported values is             ing at the 4 mm thickness. They concluded that this
    due to the method of specimen preparation and in-              could support the use of these composites to fill deep
©




    dentation techniques employed (5, 15, 16).                     cavities with high C-factor (4).
    Based on our findings, the dentin of teeth suffering           The mechanisms used to decrease contraction stress
    from severe chronic periodontitis showed less VHN              and to enhance the curing depth are different be-
    compared to healthy dentin. In agreement with our re-          tween bulk-fill resin composites. Some manufacturers
    sults, Riffle et al. and Emslie et al. found that the cer-     enhance light transmission through the resin compos-
    vical root dentin showed less microhardness scores             ite by using monomers, pigments, fillers with the
    in patients who suffer from periodontal disease or             same refractive indices. Others decrease the inorgan-


    Annali di Stomatologia 2018;IX (3):123-129                                                                            127
    H. Moosavi et al.


    ic content to enhance the light transmission and               ate microleakage in the current research. In spite of
    depth of curing, although this approach compromises            the restrictions of this investigation, although peri-
    the mechanical properties (19). Another approach to            odontal disease had a significant effect on the dentin
    achieve deeper polymerization is the use of the addi-          microhardness reduction, but no significant outcome
    tional or photo initiators like Ivocerin that is the patent-   was observed on the cervical leakage after the use of




                                                                                                            li
    ed light activator of Tetric N-Ceram BRC and is re-            conventional and BRCs. More research about long-
    sponsible for complete curing of the restoration. Ivo-         term clinical evaluation of BRCs and periodontally in-




                                                                                                          na
    cerin is more light reactive than camphorquinone, acts         volved teeth are required.
    as a polymerization booster and allows polymerization
    in deeper increments without compromising the physi-
    cal properties of the resin composite (20, 21).                Conclusions
    Tetric N-Ceram BRC has the specially patented filler




                                                                                                        io
    that relieves contraction stresses (20). The manufac-          VHN values of healthy dentin were more than peri-
    turer of this material claimed that due to the low elas-       odontally involved teeth at all depths. Conventional
    tic modulus of this patented filler, the shrinkage             resin composite showed more cervical microleakage




                                                                               az
    stress reliever expands slightly during polymerization         than BRCs bounded to both healthy and periodontally
    and plays like a spring amongst the glass fillers with         involved dentin, but the differences between two resin
    the higher modulus of elasticity. Also, Tetric N-Ceram         composites were not statistically significant. Addition-
    bulk fill has prepolymerized fillers which attenuate           ally, periodontally involved dentin showed higher mi-




                                                                             rn
    elastic modulus and their translucency helps to pass           croleakage scores compared to healthy dentin, al-
    the photons through the substance. Finally, polymer-           though statistical analysis showed no significant dif-
    ization shrinkage and contraction stress in Tetric N-          ferences between them.
    Ceram BRC decrease during polymerization, obtain a




                                                            te
    good marginal seal and allow increments up to 4 mm
    to be inserted (20, 22, 23). However, in our research          References
    none of the two resin composites was able to inhibit
    perfectly cervical microleakage.
                                                          In       1.  Bagis Y, Baltacioglu I, Kahyaogullari S. Comparing mi-
    In line with our findings, some research concluded that            croleakage and the layering methods of silorane-based resin
    any significant differences were not recorded in the               composite in wide Class II MOD cavities. Operative Dentistry.
                                                                       2009;34(5):578-585.
    cervical microleakage scores for incrementally com-
                                                                   2. Phillips RW, Avery DR, Mehra R, Swartz ML, McCune RJ.
                              ni
    pared to the bulk fill composites restored teeth (7, 24).
                                                                       Observations on a composite resin for Class II restorations:
    Most class II cavities extend up to or beyond the CEJ              three-year report. The Journal of prosthetic dentistry.
    so that the cervical margins will be placed at the                 1973;30(6):891-897.
    dentin surfaces and may cause a weak marginal seal
                            io

                                                                   3. Leevailoj C, Cochran M, Matis B, Moore B, Platt J. Micro-
    and microleakage between the dentin and composite                  leakage of posterior packable resin composites with and with-
    resin (25). Cavosurface margins restricted to enamel               out flowable liners. Operative Dentistry. 2001;26(3):302-307.
    can preserve marginal seal of cavity preparation be-           4. El-Damanhoury H, Platt J. Polymerization shrinkage stress
                          iz



    cause of the strong adhesion between the enamel                    kinetics and related properties of bulk-fill resin composites.
                                                                       Operative dentistry. 2014;39(4):374-382.
    and resin adhesive. Additionally, the internal stress of
                                                                   5. Rautiola C, Craig R. The microhardness of cementum and
    the composites materials at dentin surfaces are often
           Ed




                                                                       underlying dentin of normal teeth and teeth exposed to pe-
    more than the bond strength and subsequently gap                   riodontal disease. Journal of Periodontology. 1961;32(2):113-
    formation occurs at the resin-dentin interface (26).               123.
    Past investigations have demonstrated that the min-            6. Demarco F, Ramos O, Mota C, Formolo E, Justino L. Influ-
    eral substance of dentin plays an essential role in the            ence of different restorative techniques on microleakage in
    bond strength of composite to dentin (27). Yoshiyama               class II cavities with gingival wall in cementum. Operative den-
    et al. explained that when the dentin was undergoing               tistry. 2001;26(3):253-259.
 IC




    chemical and structural changes naturally, fewer               7. Patel P, Shah M, Agrawal N, Desai P, Tailor K, Patel K. Com-
                                                                       parative evaluation of microleakage of class II cavities restored
    resin tags formed because of the existence of mineral
                                                                       with different bulk fill composite restorative systems: An in
    sclerotic casts in the dentin tubules. Also, a limited             vitro study. J Res Adv Dent. 2016;5(2):52-62.
    resin infiltration layer was seen at the external mar-
C




                                                                   8. Shinkarenko T, Rumiantsev V, Egorova E, Eliseeva T. Ma-
    gins of the natural lesions. They explained that the               trix metalloproteinases in periodontitis. Stomatologiia.
    lower bond strength between resin and dentin struc-                2013;92(2):77.
    tures in natural lesions was because of the long term          9. Sorsa T, Tjäderhane L, Konttinen YT, Lauhio A, Salo T, Lee
    exposure to the oral cavity and, thereby, the pres-                HM, et al. Matrix metalloproteinases: contribution to patho-
©




    ence of unknown substances in dentin and thinner                   genesis, diagnosis and treatment of periodontal inflamma-
                                                                       tion. Annals of medicine. 2006;38(5):306-321.
    hybrid layer (28).
                                                                   10. Lee W, Aitken S, Sodek J, McCulloch C. Evidence of a di-
    Dye extraction technique has employed to assess the
                                                                       rect relationship between neutrophil collagenase activity and
    marginal integrity and the ability of dental materials to          periodontal tissue destruction in vivo: role of active enzyme
    seal the cavosurface margins. This method is simple                in human periodontitis. Journal of periodontal research.
    and presents the characteristic of micro-leakage                   1995;30(1):23-33.
    quantitatively (29). Therefore it was utilized to evalu-       11. Fuentes V, Toledano M, Osorio R, Carvalho RM. Micro-


    128                                                                                  Annali di Stomatologia 2018;IX (3):123-129
    Periodontally involved teeth and bulk-fill composites


          hardness of superficial and deep sound human dentin. Jour-             resin. Operative dentistry. 2015;40(2):172-180.
          nal of Biomedical Materials Research Part A: An Official Jour-     21. Furness A, Tadros MY, Looney SW, Rueggeberg FA. Effect
          nal of The Society for Biomaterials, The Japanese Society              of bulk/incremental fill on internal gap formation of bulk-fill
          for Biomaterials, and The Australian Society for Biomateri-            composites. Journal of dentistry. 2014;42(4):439-449.
          als and the Korean Society for Biomaterials. 2003;66(4):850-       22. Scientific documentation of Tetric N-Ceram Bulk Fill. Retrieved
          853.                                                                   online 11 September 2018. http://www.ivoclarvivadent.in/en-




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    12.   Kinney J, Balooch M, Marshall S, Marshall G, Weihs T. Atom-            in/p/all/tetric-n-ceram-bulk-fill
          ic force microscope measurements of the hardness and elas-         23. Hirata R, Clozza E, Giannini M, Farrokhmanesh E, Janal M,




                                                                                                                   na
          ticity of peritubular and intertubular human dentin. Journal           Tovar N, et al. Shrinkage assessment of low shrinkage com-
          of biomechanical engineering. 1996;118(1):133-135.                     posites using micro‐computed tomography. Journal of
    13.   Pashley D, Okabe A, Parham P. The relationship between                 Biomedical Materials Research Part B: Applied Biomateri-
          dentin microhardness and tubule density. Dental Trauma-                als. 2015;103(4):798-806.
          tology. 1985;1(5):176-179.                                         24. Moorthy A, Hogg C, Dowling A, Grufferty B, Benetti AR, Flem-




                                                                                                                 io
    14.   Marshall Jr GW, Marshall SJ, Kinney JH, Balooch M. The                 ing G. Cuspal deflection and microleakage in premolar teeth
          dentin substrate: structure and properties related to bond-            restored with bulk-fill flowable resin-based composite base
          ing. Journal of dentistry. 1997;25(6):441-458.                         materials. Journal of Dentistry. 2012;40(6):500-505.
    15.   Chuenarrom C, Benjakul P, Daosodsai P. Effect of inden-            25. Litonjua LA, Andreana S, Bush PJ, Tobias TS, Cohen RE.




                                                                                         az
          tation load and time on knoop and vickers microhardness tests          Noncarious cervical lesions and abfractions: a re-evaluation.
          for enamel and dentin. Materials Research. 2009;12(4):473-             The Journal of the American Dental Association. 2003;
          476.                                                                   134(7):845-850.
    16.   Yassen GH, Eckert GJ, Platt JA. Effect of intracanal medica-       26. Feilzer A, De Gee A, Davidson C. Setting stress in composite




                                                                                       rn
          ments used in endodontic regeneration procedures on mi-                resin in relation to configuration of the restoration. Journal
          crohardness and chemical structure of dentin. Restorative              of Dental Research. 1987;66(11):1636-1639.
          dentistry & endodontics. 2015;40(2):104-112.                       27. Spencer P, Wang Y, Walker M, Swafford J. Molecular struc-
    17.   Riffle A. The dentin: its physical characteristics during curet-       ture of acid-etched dentin smear layers-in situ study. Jour-




                                                                     te
          tage. The Journal of Periodontology. 1953;24(4):232-241.               nal of Dental Research. 2001;80(9):1802-1807.
    18.   Emslie R, Stack M. The micro hardness of roots of teeth with       28. Yoshiyama M, Sano H, Ebisu S, Tagami J, Ciucchi B, Car-
          periodontal disease. Dent Pract Dent Rec. 1958;9:101-113.              valho R, et al. Regional strengths of bonding agents to cer-
    19.   Corral-Núnez C, Vildósola-Grez P, Bersezio-Miranda C, Cam-             vical sclerotic root dentin. Journal of dental research.
                                                                   In
          pos A-D, Fernández Godoy E. State of the art of bulk-fill resin-       1996;75(6):1404-1413.
          based composites: a review. Revista Facultad de Odontología        29. NIK IR, NASERI EB, Majidinia S, NIK SR, GIV MJ. Effect of
          Universidad de Antioquia. 2015;27(1):177-196.                          Chlorhexidine and Ethanol on Microleakage of Composite
    20.   Jang J, Park S, Hwang I. Polymerization shrinkage and depth            Resin Restoration to Dentine. Chin J Dent Res. 2017;20
          of cure of bulk-fill resin composites and highly filled flowable       (3):161-168.
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    Annali di Stomatologia 2018;IX (3):123-129                                                                                             129
