10.59987/ads/2017.2.71-78
Aim. The purpose of this research is to investigate whether and how the adhesive bond failure site varied in relation to the material used for the orthodontic bonding and debonding technique applied.
Materials and methods. Two different methods of orthodontic debonding were included in our survey; cutters for orthodontics and debonding plier. Three different materials for the adhesion of the bracket: composite light curing, self-curing composite and glass ionomer cement. The remaining amount of adhesive on the tooth surface is an important parameter that gives information on how the location of the posting site varied during the debonding. 60 dental elements, maxillary and mandibular, previously extracted for orthodontic reasons, as well as periodontal, were included in our research. We investigated a possible significant correlation between different variables (debonding technique and materials for membership) and the ARI index.
Conclusions. The use of orthodontic cutters or debonding pliers does not affect the adhesive bond failure site and both techniques have a tendency to leave a significant amount of adhesive on the surface enamel. In the resin-reinforced glass ionomer cements, detachment occurs at the interface enamel-adhesive and this pattern of detachment increases the risk of the enamel damage during debonding. In both types of composite resins (photopolymerizable or self-curing), the detachment occurs at the interface bracketing adhesive. In this case the amount of remaining adhesive material on the tooth must be removed with further methods, which in addition, increase the risk of iatrogenic injury as well as the working hours.
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Annali di stomatologia
adhesion
Comparison of two different debonding techniques in orthodontic treatment
Text.Serial.Journal
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Original Article
2022-08-10
2022-08-10
2017-06-01
2023-12-04
71-78
Ann Stomatol (Roma)
R. Di Giorgio
2017
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1971-1441
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adhesion
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78
Comparison of two different debonding techniques in orthodontic treatment
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                                                                                                Original article


    Comparison of two different debonding techniques
    in orthodontic treatment




                                                                                             li
                                                                                           na
    Luca Piccoli DDS, PhD                                  age during debonding. In both types of composite
    Guido Migliau MD, DDS                                  resins (photopolymerizable or self-curing), the de-
    Laith Konstantinos Besharat DDS, PhD                   tachment occurs at the interface bracketing adhe-




                                                                                         io
    Stefano Di Carlo MD, DDS, PhD                          sive. In this case the amount of remaining adhe-
    Giorgio Pompa MD, DDS, PhD                             sive material on the tooth must be removed with
    Roberto Di Giorgio MD, DDS, PhD                        further methods, which in addition, increase the




                                                                     az
                                                           risk of iatrogenic injury as well as the working

    Department of Oral and Maxillofacial Sciences,
                                                           hours.

    “Sapienza” University of Rome, Rome, Italy             Key words: orthodontics, debonding, adhesion.




                                                                   rn
                                                           Introduction
    Laith Konstantinos Besharat
    Corresponding author:

    Department of Oral and Maxillofacial Sciences,         In order to guarantee the success of a fixed orthodon-




                                                       te
    “Sapienza” University of Rome                          tic treatment, efficient adhesion of the bracket on the
    Via Caserta 6                                          surface of the tooth is required for the duration of the
    00161 Rome, Italy                                      orthodontic treatment, which prevents an eventual
                                                           detachment or change of its initial position during the
                                                     In
    E-mail: besharatlk84@yahoo.it
                                                           application of orthodontic force.
                                                           On the other hand, at the end of the treatment, the
                                                           procedure of debonding should be able to be imple-
                                                           mented effectively, allowing the detachment of the
    Summary
                                ni

                                                           bracket from the tooth surface as well as leaving the
                                                           enamel surface intact.
    Aim. The purpose of this research is to investi-
                                                           The adhesive system for orthodontic attachments
    gate whether and how the adhesive bond failure
                              io


                                                           should fulfill two tasks which in fact are mutually ex-
    site varied in relation to the material used for the
                                                           clusive, therefore the majority of the studies in this
    orthodontic bonding and debonding technique
                                                           field of orthodontics has focused on the evaluation of
    applied.
                                                           the mechanical and physical properties of the adhe-
                            iz



    Materials and methods. Two different methods of
                                                           sive materials used for the direct bonding of ortho-
    orthodontic debonding were included in our sur-
                                                           dontic brackets, including their adhesive strength and
    vey; cutters for orthodontics and debonding plier.
                                                           enamel condition during, and at the end of the treat-
            Ed




    Three different materials for the adhesion of the
    bracket: composite light curing, self-curing com-      ment (1, 2).
    posite and glass ionomer cement. The remaining         It has been shown that each material presents differ-
    amount of adhesive on the tooth surface is an im-      ent molecular structures and different physico-me-
    portant parameter that gives information on how        chanical properties, which also justifies the different
    the location of the posting site varied during the     behaviors in response to the applied force during the
                                                           debonding procedures. In particular, it was shown
 IC




    debonding. 60 dental elements, maxillary and
    mandibular, previously extracted for orthodontic       that the forces applied to allow the detachment of the
                                                           bracket from the enamel surface do not act in a ho-
                                                           mogenous way, but focus mainly on specific weak-
    reasons, as well as periodontal, were included in

                                                           nesses of the adhesive bond (3-5).
    our research. We investigated a possible signifi-
C




                                                           In detail regarding the failure of the adhesive bond
    cant correlation between different variables

                                                           site, Artun and Bergland in 1984 developed an index
    (debonding technique and materials for member-

                                                           called ARI (Adhesive Remnant Index), thus identify-
    ship) and the ARI index.

                                                           ing two different failure patterns in the tooth-bracket-
    Conclusions. The use of orthodontic cutters or
©




                                                           adhesive system, namely the formation of a gap in
    debonding pliers does not affect the adhesive

                                                           the enamel-adhesive or bracket-adhesive bonding
    bond failure site and both techniques have a ten-

                                                           surfaces.
    dency to leave a significant amount of adhesive

                                                           Inquiring about the posting site is crucial due to the
    on the surface enamel. In the resin-reinforced

                                                           fact, that both failure modes have 0 clinical implica-
    glass ionomer cements, detachment occurs at the

                                                           tions that should be considered during an orthodontic
    interface enamel-adhesive and this pattern of de-
    tachment increases the risk of the enamel dam-

    Annali di Stomatologia 2017;VIII (2):71-78                                                                  71
    L. Piccoli et al.


    treatment. In the first case, namely in the event of a     •   Intact vestibular surface
    detachment at the enamel-adhesive interface in-            •   Absence of caries
    creases the risk of fractures and permanent damage         •   No fillings
    to the enamel, whilst in the second case when follow-      •   Lack of enamel defects.
    ing the fact that the gap formed between the bracket
    and adhesive leaving a large amount of composite on        The extracted dental elements were thoroughly
    the vestibular surface of the tooth, the risk of damage    cleaned from any tissue and fluid and stored in dis-




                                                                                                   li
    to the enamel will be reduced but additional proce-        tilled water and 1% thymol for 24 hours to prevent de-




                                                                                                 na
    dures to remove the composite from the tooth surface       hydration.
    will be necessary, which will then result in an in-        Subsequently they were stored in distilled water until
    crease of working time (6).                                the moment of their use.
    In light of the above and the growing scientific inter-    Before use, the vestibular surface of all the teeth was
    est on the subject, it seemed interesting to focus on      cleaned and polished with a rubber pad mounted on




                                                                                               io
    the matter and in particular investigate whether and       a low-speed handpiece for 10 seconds.
    how the adhesive bond failure site varied in relation      The sample was divided into 6 groups each one con-
    to the material used for the orthodontic bonding and       sisting of 10 dental elements (Table 1).




                                                                         az
    debonding technique used. The purpose of this re-
    search is to evaluate the possible influence of two dif-
    ferent methods of orthodontic debonding: Cutters for
    Orthodontics and debonding pliers.
                                                               Bonding of the bracket to the enamel




                                                                       rn
                                                               surface

                                                               Procedures for bonding of the bracket in groups 1
    Materials and methods                                      and 2




                                                        te
    Three different materials for the adhesion of the          The vestibular surface of dental elements was etched
                                                               MATERIALS: light-curing adhesive system

    bracket were used:                                         using 37% orthophosphoric acid for 30 seconds, was
    1. Composite light curing                                  subsequently rinsed for 15 seconds and dried with air
                                                      In
    2. Self-curing composite                                   jet to obtain a chalky appearance of the enamel.
    3. Glass ionomer cement.                                   It was then applied with a brush, the © Transbond XT
                                                               primer (3M Unitek, Monrovia, California) on the previ-
    The remaining amount of adhesive on the tooth sur-         ously etched surface and stretched by a gentle jet of
    face is an important parameter that gives information      air to obtain a thin layer of primer disposed uniformly
                             ni

    on how the location of the posting site varied during      on the enamel.
    the debonding.                                             The primer was photoactivated using a curing light for
    The study is divided into four different phases:           10 seconds.
                           io


    1. Preparation and subdivision of the sample:              At this point, we selected the self-ligating bracket cor-
    the sample has been properly prepared and divided          responding to the teeth used, and after placing on the
    into groups;                                               bracket base an adequate amount of light-curing
                         iz



    2. Bonding:                                                composite © Transbond XT Adhesive Paste, the at-
    three different materials were used to allow the adhe-     tack was positioned on the surface of the correspond-
    sion of the bracket to the extracted teeth;                ing tooth with DOOR pliers.
            Ed




    3. Debonding:                                              Once we removed the excess material from the pe-
    we used two different methods of debonding to re-          riphery of the bracket the composite was light-cured
    move the bracket previously applied to the vestibular      with a light power equal to 740 mW/cm2 and a wave-
    surface of the teeth;                                      length of 470 nm to 480 nm for 20 seconds on each
    4. Evaluation of sticker remaining:                        side (mesial, distal, incisal and gingival).
    we evaluated the remaining amount of composite or
 IC




    cement on the surface of the tooth through the ARI
    index;
                                                               Procedures for bonding of the bracket in groups 3

    5. Statistical analysis of data:
                                                               and 4

    we investigated a possible significant correlation be-     The vestibular surface of the dental elements was
                                                               MATERIALS: self-curing adhesive system
C




    tween variables (debonding technique and materials         etched using 37% orthophosphoric acid for 30 seconds,
    for membership) and the ARI index.                         and was subsequently rinsed for 15 seconds and dried
                                                               with air jet to obtain a chalky appearance of the enamel.
                                                               A thin layer of Ortho-one No Mix Primer (BISCO Inc.
©




                                                               U.S.A.) was applied with a brush both on the tooth
                                                               surface previously etched, and stretched with a faint
    Preparation and subdivision of the sample

    The sample consists of 60 dental elements, both            jet of compressed air, or on the base of the bracket.
    maxillary and mandibular previously extracted for or-      The primer in this case contains a catalyst molecule
    thodontic reasons, as well as periodontal selected ac-     that once in contact with the adhesive paste initiates
    cording to the following sample inclusion criteria:        the curing process.

    72                                                                            Annali di Stomatologia 2017;VIII (2):71-78
    Comparison of two different debonding techniques in orthodontic treatment


    Table 1. Sample division into six groups.


                                                                        Adhesive           Debonding              Bracket
                                Etching               Primer
                                                                        composite          Technique               type




                                                                                                           li
                                 37%
                                                 primer Transbond




                                                                                                         na
                            Orthophosphoric                           Transbond XT         Cutters for
          Group 1                                       XT                                                  Self ligating bracket
                                  acid                                    (3M)            Orthodontics
                                                       (3M)
                                 (3M)

                                 37%
                                                 primer Transbond




                                                                                                       io
                            Orthophosphoric                           Transbond XT
          Group 2                                       XT                               Debonding plier    Self ligating bracket
                                  acid                                    (3M)
                                                       (3M)
                                 (3M)




                                                                                 az
                                 37%
                                                 Ortho-one No Mix    Ortho one No Mix
                            Orthophosphoric                                                Cutters for
          Group 3                                     Primer               Paste                            Self ligating bracket
                                  acid                                                    Orthodontics
                                                      (Bisco)             (Bisco)
                                 (3M)




                                                                               rn
                                 37%
                                                 Ortho-one No Mix    Ortho-one No Mix
                            Orthophosphoric
          Group 4                                     Primer               Paste         Debonding plier    Self ligating bracket
                                  acid




                                                              te
                                                      (Bisco)             (Bisco)
                                 (3M)
                                                            In
                                                Liquid             Powder
                            Etching            of glass            of glass      Debonding Technique           Bracket type
                                            onomer cement       ionomer cement
                                ni

                        10% Polyacrylic                           Fuji Ortho
         Group 5                            Fuji Ortho liquid                    Cutters for Orthodontics   Self ligating bracket
                            acid                                   powder
                              io


                        10% Polyacrylic                           Fuji Ortho
         Group 6                            Fuji Ortho liquid                        Debonding plier        Self ligating bracket
                            acid                                   powder
                            iz
            Ed




    At this point an adequate amount of adhesive paste                ionomer cement (Fuji Ortho and Fuji Ortho liquid
    (Ortho-one No Mix paste) is placed on the bracket                 powder) were mixed according to the manufacturer’s
    base and the attack is positioned on the surface of               instructions, and once it reached the desired consis-
    the tooth with a clamp bracket, making sure to                    tency, the glass ionomer cement was applied with a
    properly join the attack on the enamel surface and to             brush in a thin layer on the bracket base. The attack
    remove any excess material from the periphery of the              was positioned on the surface of the corresponding
 IC




    bracket.                                                          tooth, which was previously cleaned and polished.
    In this case the polymerization, made possible by the             Excess material from the periphery of the bracket
    catalyst contained in the primer, occurred in about 5             was removed with a calliper bracket. The material
    minutes.                                                          was light cured with a light power equal to 740
C




                                                                      mW/cm2 and a wavelength of 470 nm to 480 nm for
                                                                      20 seconds on each side (mesial, distal, gingival and
                                                                      incisal).
    Procedures for bonding of the bracket in groups 5
    and 6
©




    The vestibular surface of the teeth was conditioned
    MATERIALS: glass ionomer cement

    with 10% polyacrylic acid for 20 seconds, sub -                   In all six groups metallic self-ligating brackets were
                                                                      Bracket used

    sequently rinsed for 15 seconds, and adequately                   used, the base of the bracket had a single 80 gauge
    dried with an air jet afterwards.                                 mesh morphology with a mesh spacing equal to 3,2 x
    The paste and liquid components of the glass                      10 -2 mm2.



    Annali di Stomatologia 2017;VIII (2):71-78                                                                                 73
    L. Piccoli et al.


                                                                scans with a special software which made it possible
                                                                to calculate the perimeter and the area occupied by
    Debonding

                                                                the residual material (Fig.1).
                                                                By calculating the area occupied by the remaining ad-
    Procedures in groups 1-3-5 debonding

    The brackets attached to the surface of the dental el-      hesive material and having available the information
    METHOD USED: cutters for orthodontics

    ements were removed through the use of nippers for          relating to the area of the base of the bracket used it
    orthodontics, by placing the beaks of the pliers at the     was possible to calculate the index ARI (Adhesive




                                                                                                     li
    base of the bracket fins and applying a force directed      Remnant Index) described by Artun and Bergland.
    mesio-distally to promote the detachment of the




                                                                                                   na
                                                                The ARI Index involves the assignment of values
    bracket from the enamel surface.                            ranging from 0 to 3:
                                                                0: Absence of adhesive material remaining on the
                                                                    tooth surface
                                                                1: Presence of less than half of the adhesive materi-
    Procedures in groups 2-4-6 debonding




                                                                                                 io
    The dental elements were subjected to a debonding               al remaining on the tooth surface
    METHOD USED: debonding plier

    procedure through the use of a dedicated tool. The          2: Presence of more than half of the adhesive mate-
    beaks of the pliers of the debonding chisel were posi-          rial remaining on the tooth surface




                                                                           az
    tioned as near as possible to the base of the bracket       3: Presence of all of the adhesive material on the
    and shear force was applied to allow the detachment             tooth surface.
    of the bracket.




                                                                         rn
                                                                Statistical analysis
    Evaluation of the remaining quantity of
    adhesive material on the dental surface                     Statistical analysis was performed using SPSS Inc.
                                                                ver. 13.0, Chicago, IL, USA. Chi-squared test was




                                                         te
                                                                used for statistical evaluation of proportions. In cases
    The dental elements, after the debonding procedures
    Scan 3D
                                                                of more than 2 independent means we used the
    were subjected to 3D scans.
                                                                ANOVA test. A p-value of less than 0.05 was consid-
    The scanner used was a SYNERGY SCAN, which is
                                                       In
                                                                ered significant. A 95% CI was used in all of the
    a sophisticated 3D optical scanner that can acquire
                                                                analysis. In order to assure data reliability, data were
    non-contact three-dimensional shapes.
                                                                entered in two different personal computers by two
    The technology used in the scanner is called active
                                                                examiners; the two data files were compared in order
    stereo vision and is the projection of a structured light
                                                                to detect entry errors. The two files resulted identical.
                             ni

    pattern on the surface of interest that is captured
                                                                Statistical tests were performed, to investigate any
    through two cameras.
                                                                significant correlations between the type of material,
    Advanced image processing algorithms to retrieve
                                                                the debonding technique and the ARI index. For fur-
                           io


    the aquiered surface’s depth were used and a recon-
                                                                ther analysis, the statistical Chi-square test was used.
    struction of a three-dimensional image that can be
    easily viewed and manipulated on the PC screen was          The Chi-square test is a nonparametric statistical test,
    achieved.                                                   which allows the comparison of two related reports or
                         iz



    The entire scanning step is fully automated with the        frequencies, in order to exclude, with a certain degree
    help of an automated rotating table that allows us to       of probability, that their difference is due to the chance.
    acquire different views of the object.                      Any statistical program will result in a transformation of
            Ed




    The teeth were placed on Support Single Silicon and         the test result in probability (p). This probability of error
    dulled by spray cleaner before being subjected to           should also be assessed according to the level of sig-
    scanning.                                                   nificance chosen by the investigator.
    This is because many objects have a surface that is
    not easy to detect with the light beam used by the
    scanner.
 IC




                                                                Results
    If the objects are transparent, too dark, opaque, or
    black they have refractive and reflective qualities,        We carried out two different surveys.
    which do not allow the camera to detect the ray of          In the first we compared the different materials used
    light which is deformed or reflected erratically. In        for the bonding and the ARI index, while in the sec-
C




    these cases it is impossible to perform the scanning        ond we compared the debonding techniques to the
    unless you opacify the object with preferably a white       ARI index.
    opaque layer, which renders the area appropriate.
    The spray used (Renfert - scan spray) allows treating
©




    the surface at an optimal level for the scan.               In this study we used the statistical Chi-square test
                                                                Survey 1

                                                                with 95% confidence interval, to determine any signif-
                                                                icant correlation between the three different materials
    To determine the remaining amount of adhesive on            used for orthodontic bonding (a light-curing compos-
    Calculation of the ari index

    the labial surface of the dental elements after             ite, a composite and a self-curing glass ionomer ce-
    debonding, we processed the images of the digitized         ment), and the ARI index.

    74                                                                               Annali di Stomatologia 2017;VIII (2):71-78
    Comparison of two different debonding techniques in orthodontic treatment


                                                                                        Figure 1. Digitized scans.




                                                                                                   li
                                                                                                 na
                                                                                               io
                                                                            az
                                                                          rn
                                                         te
                                                       In
                                ni
                              io
                            iz
            Ed
 IC




    Between the dental elements in which a light-cured            Between the elements where dental self-curing com-
    composite for the bonding of orthodontic brackets             posite for the bonding of orthodontic brackets was
    was used on a total of 20 teeth:                              used on a total of 20 teeth:
    • 1 element reported value of ARI 0                           • 4 items reported a value of ARI 0
C




    • 5 elements have reported a value of ARI 1                   • 4 elements have reported a value of ARI 1
    • 11 elements have reported a value of ARI 2                  • 5 elements have reported a value of ARI 2
    • 3 elements have reported a value of ARI 3.                  • 7 elements have reported a value of ARI 3 (Fig. 2).
    Between the dental elements in which a self-curing            The graph shows that among the elements in which a
©




    composite for the bonding of orthodontic brackets             glass ionomer cement was used, 61% of the sample
    was used on a total of 20 teeth:                              presented a value of ARI 0 (no remaining sticker on
    • 4 items reported a value of ARI 0                           the surface of the tooth) compared to 8% of the items
    • 4 elements have reported a value of ARI 1                   in which a light-curing composite was used and 31%
    • 5 elements have reported a value of ARI 2                   among the elements in which a self-curing composite
    • 7 elements have reported a value of ARI 3.                  was used (Fig. 3).

    Annali di Stomatologia 2017;VIII (2):71-78                                                                       75
    L. Piccoli et al.




                                                                                                    li
                                                                                                  na
                                                                                                io
                                                                           az
                                                                         rn
    Figure 2. First survey (p value = 0.05).




                                                           te
                                                         In
                               ni
                             io
                           iz
            Ed
 IC




    Figure 3. ARI 0 percentage in the three adhesive materials.


                                                                  Among the elements in which a wire cutter for ortho-
    In this analysis we investigated by the use of the sta-       dontics was used to remove brackets from the buccal
    Survey 2
C




    tistical Chi-square test, with a 95% confidence inter-        surface, out of a total of 30 teeth:
    val, any significant correlation between the two differ-      • 9 elements reported a value of ARI 0
    ent debonding techniques and the ARI index.                   • 8 elements reported a value of ARI 1
    Among the elements in which pliers were used to re-
©




                                                                  • 8 elements reported a value of ARI 2
    move brackets from the vestibular surface, out of a
                                                                  • 5 elements reported a value of ARI 3.
    total of 30 teeth:
    • 4 elements reported a value of ARI 0
    • 6 elements reported a value of ARI 1                        This investigation showed no significant values (p
    • 12 elements reported a value of ARI 2                       value> α) (Fig. 4).
    • 8 elements reported a value of ARI 3.

    76                                                                              Annali di Stomatologia 2017;VIII (2):71-78
    Comparison of two different debonding techniques in orthodontic treatment




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         '"




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                                                                            rn
                 ,8((.)/!!9*)!*)(-*3*+(0,/                  3.5*! +30
                                                                    ! +6!1:0.)/
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    Figure 4. Correlation between the two different debonding techniques and the ARI index.


    Discussion

                                                          te
    The finding of a statistically significant correlation be-
                                                                   In particular the highest values of ARI index were
                                                                   recorded with the use of a light-cured composite.
                                                                   This behavior is probably due to an incomplete poly-
                                                        In
    tween the type of material used for orthodontic bond-          merization of the resin below the base of the bracket
    ing and the Adhesive Remnant Index, confirms the               due to the difficulty of the curing light to reach and
    data reported in the literature according to which, the        activate the material located immediately below the
    adhesive bond failure site during the debonding                metal base. In addition, the effect of air entrapment
                                ni

    varies depends on the material used for bonding (7).           below the bracket during the procedures of bonding,
    In particular, the results show that in the elements in        allows the oxygen to cause a partial inhibition of the
    which a glass ionomer cement was used, the adhe-               free radicals necessary for polymerization and can be
                              io


    sive failure in the debonding procedures resulted              responsible for the failure of the adhesive bond in
    mostly in the adhesive enamel interface, unlike ele-           bracket-adhesive interface. This effect is only report-
                                                                   ed in the literature for the light cured composites (14,
    ments in which a composite was used where the fail-
                                                                   15).
                            iz



    ure of the bond took place mostly in the bracket ad-
                                                                   The reasons for the same behavior of the self-curing
    hesive interface.
                                                                   composites, however, lie in their high rate of polymer-
    The reasons that the glass ionomer cements binds
                                                                   ization which create a very high adhesive force, giv-
            Ed




    more efficiently to the metal base of the bracket in re-
                                                                   ing an explanation for the material separation in the
    spect to composite resins are to be discovered, be-
                                                                   bracket adhesive interface.
    cause unlike the latter, the glass ionomer cements
                                                                   It is reported in the literature that when you reach
    permit a chemical bond both to the base of the brack-
                                                                   very high values of bond strength, applying a separa-
    et and the enamel.                                             tion force to allow for the debonding of the bracket, a
    In addition, in the glass ionomer cement, the mechan-          fracture plane is created that propagates into the ma-
 IC




    ical component of the adhesive bond, which is made             terial and at the interface-bracketing adhesive.
    possible by the creation of micropores in the enamel,          No statistically significant differences were found be-
    is greatly diminished, because these materials do not          tween the two debonding techniques used (orthodon-
    need an etching with strong acid (orthophosphoric              tic wire cutters and debonding pliers) in relation to the
C




    acid at 37%) which demineralizes the enamel (8, 9),            ARI index.
    but rather need etching with a weak acid (10% poly-            Both tools used have shown a tendency to leave a
    acrylic acid), which demineralizes very mildly the             significant amount of adhesive on the enamel sur-
    enamel and has mainly the aim of cleaning the sur-             face.
©




    face from the acquired film and debris (10-13).                These findings are similar to data reported in several
    As for the elements in which composite resins were             previous studies (3, 16-19).
    used (photopolymerizable and self-curing) for ortho-           Our results are in concordance with international liter-
    dontic bonding, the adhesive failure in the debonding          ature and confirm that during debonding the type of
    procedures, occurred for the majority of the samples           force applied affects the remaining amount of adhe-
    at the bracket adhesive interface.                             sive and not the type of instrument used.

    Annali di Stomatologia 2017;VIII (2):71-78                                                                           77
    L. Piccoli et al.


    In particular by applying shear forces on the gap site                      totoxicity of conventional and resin modified glass ionomer
    localizes mainly to the interface bracket-adhesive,                         cements. Bosnian journal of basic medical sciences/Udruzen-
    while applying tensile forces the posting site is trans-                    je basicnih mediciniskih znanosti= Association of Basic Med-
    ferred to the interface between the enamel and the                          ical Sciences. 2012;12(4):273-278.
                                                                          6.    Salehi P, Pakshir H, Naseri N, Baherimoghaddam T J. The
    adhesive (20).
                                                                                effects of composite resin types and debonding pliers on the
    Both debonding orthodontic instruments analyzed in                          amount of adhesive remnants and enamel damages: a stere-
    the current study apply a shear force to the bracket




                                                                                                                    li
                                                                                omicroscopic evaluation. Dent Res Dent Clin Dent Prospects.
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                                                                                                                  na
                                                                          7.    Rasheed NA. A comparative clinical study between light cured
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                                                                          8.    Yassaei, Soghra, Azadeh Soleimanian, and Zahra Ebrahi-
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                                                                                Brackets on Enamel Surface and Pulpal Temperature.
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                                                                                      az
    both techniques have a tendency to leave a signifi-                         tistry. 2014;112(2):122-135.
    cant amount of adhesive on the surface enamel.                        10.   Navimipour EJ, Oskoee SS, Oskoee PA, Bahari M, Rikhte-
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                                                                                    rn
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                                                                          12.   Ravindranath MJ, et al. Comparison of Morphological Vari-




                                                                  te
    In both types of composite resins (photopolymeriz-                          ation and Shear Bond Strength Between Conventional
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                                                                In
                                                                          13.   Sargison AE, McCabe JF, Millett DT. A laboratory investi-
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C
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    78                                                                                            Annali di Stomatologia 2017;VIII (2):71-78
