|Year : 2018 | Volume
| Issue : 2 | Page : 242-247
Microleakage of Different Adhesive Systems in Primary Molars Prepared by Er: YAG Laser or bur
IO Kalyoncu, F Eren-Giray, N Huroglu, E Egil, I Tanboga
Department of Pediatric Dentistry, Faculty of Dentistry, Marmara University, Istanbul, Turkey
|Date of Acceptance||21-Mar-2017|
|Date of Web Publication||21-Feb-2018|
Dr. I O Kalyoncu
Department of Pediatric Dentistry, Faculty of Dentistry, Marmara University, Basibüyük, Istanbul
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background and aim: This study aimed to examine the microleakage of class V cavities of primary molars prepared by either a conventional dental bur or Er:YAG laser and one of two different adhesive systems. Methods: A total of 50 tooth samples from primary molars were used in this study. They were randomly assigned into five experimental groups of 10 samples each, according to the cavity preparation technique and the type of adhesive system applied to the cavities. Following cavity preparation, etching, bonding, and filling steps, samples were dyed using basic fuchsine and were sectioned longitudinally in buccolingual direction. Percentages of dye penetration at gingival and occlusal margins were calculated for each group. Results: Overall, microleakage scores of gingival margins were significantly higher than those of occlusal margins (P < 0.001). The group that underwent laser preparation, laser etch, and self-etch bonding procedures had worse microleakage scores for gingival margins. However, all groups had similar occlusal scores (P > 0.05). Conclusion: Self-etch bonding systems and cavity preparation with Er:YAG laser may be an alternative to conventional restoration of primary molars with compomers. Further studies are warranted to fully elucidate the effect of laser-based etching techniques in cavities prepared by laser.
Keywords: Adhesive system, cavity preparation, microleakage, primary molar
|How to cite this article:|
Kalyoncu I O, Eren-Giray F, Huroglu N, Egil E, Tanboga I. Microleakage of Different Adhesive Systems in Primary Molars Prepared by Er: YAG Laser or bur. Niger J Clin Pract 2018;21:242-7
|How to cite this URL:|
Kalyoncu I O, Eren-Giray F, Huroglu N, Egil E, Tanboga I. Microleakage of Different Adhesive Systems in Primary Molars Prepared by Er: YAG Laser or bur. Niger J Clin Pract [serial online] 2018 [cited 2022 May 19];21:242-7. Available from: https://www.njcponline.com/text.asp?2018/21/2/242/225939
| Introduction|| |
Microleakage induced by polymerization shrinkage continues to be a major concern for the clinical durability of resin-based dental restorations. Microleakage is related to the bonding quality and polymerization shrinkage of adhesives. Although improved adhesive systems have been developed, they do not completely prevent microleakage at enamel and dentin margins. Also, instruments utilized during cavity preparation have an impact on the occurrence of microleakage.
With the use of conventional diamond burs, the cavity surface may be covered by debris consisting of organic and nonorganic material that is termed as the “smear layer,” and may predispose resin-based restorations to microleakage. Although the increasingly used laser techniques are not associated with smear layer formation, they may lead to structural changes on the enamel and dentin with a subsequent risk of microleakage.,
Adhesive systems have “etch-and-rinse” or “self-etch” features, defined on the basis of their respective application procedures and adhesion mechanisms. Self-etching adhesive systems have no separate acid etching step and contain acidic monomers which can etch both enamel and dentin surfaces like the primer does, thus penetrating the tooth surface for resin infiltration into demineralized dentin. The self-etch systems have been classified as two-step and one-step (all-in-one) adhesives. Recently introduced one-step self-etch systems (all-in-one) incorporate all the components of an adhesive system (etchant, primer, and bonding resin) into a single solution and combine all the three bonding steps into a single application. Generally, self-etching adhesives are preferred materials because they eliminate the washing and drying steps, save chairside time, which is very important for pediatric dentistry, and reduce procedural errors.
The widespread use of adhesive dentistry in pediatric patients and an increasing use of laser technology in dental practice are paralleled by a trend that prompts a growing interest in the interaction between adhesive systems and lased primary dentin substrates. On the contrary, since primary and permanent teeth exhibit many structural and morphological differences, the results from studies on permanent teeth cannot be extrapolated to primary teeth in most occasions. Also, studies evaluating the use of laser systems in primary teeth for cavity preparation prior to adhesive use are scarce.
The aim of this in vitro study was to evaluate the microleakage of class V cavities of primary molars prepared by either a conventional dental bur or Er:YAG (erbium, chromium: yttrium aluminum garnet) laser and two different adhesive systems.
| Materials and Methods|| |
Sample Preparation and Study Groups
A total of 25 freshly extracted restoration- and caries-free primary molar teeth were selected randomly for the study. The teeth were cleaned of calculus, soft tissue, and debris with hand instrumentation and placed in a 0.5% chloramine T solution for disinfection for 24 hours. The teeth were stored in distilled water for a maximum duration of 6 months until the time of analysis, as recommended by the International Organization for Standardization (ISO, Guidance on Testing of Adhesion to Tooth Structure. International Organization for Standardization, TR 11405,1-4, Geneva, Switzerland, 1994). To prevent bacterial growth, water was renewed weekly. The collection procedure for the extracted teeth was approved by all patients and by the relevant ethics committee.
The teeth were mounted in a cold-curing acrylic resin and kept in cold water until the resin was completely cured, in order to avoid the thermal effects generated by the resin curing process and were subsequently divided in half in a mesiodistal direction using a diamond blade (15.2 cm ˣ 0.5, 6'' Dia. X 0.20'' Buehler, USA). The pulp chambers of the tooth were sealed with glass ionomer restorative material (Fuji II LC, GC Corporation, Tokyo, Japan) and a total of 50 tooth samples were obtained. Then, they were randomly assigned into five experimental groups of 10 samples each, according to the cavity preparation technique and the type of adhesive system applied to the cavities according to manufacturer's instructions, as outlined below. Study groups were: Group 1, bur preparation, nonrinse etch, standard bonding (control group); Group 2, bur preparation and self-etch bonding; Group 3, laser preparation, nonrinse etch, standard bonding; Group 4, laser preparation, laser etch, self-etch bonding; Group 5, laser preparation, no etching, self-etch bonding.
Cavity Preparation by Bur or Laser
Standardized class V cavities (1.5-mm deep, 3-mm long, and 2-mm wide, with the occlusal margin in enamel and the cervical margin extending 0.5 mm below the cemento-enamel junction) were prepared at the cemento-enamel junction of each primary molar sample using metal templates. All cavity preparations were done by a single dentist using burs at a high-speed handpiece under water cooling or an Er:YAG laser system (Fotona Medical Lasers, Fidelis PLUS Er:YAG and Nd:YAG Dental Laser, Ljubljana, Slovenia). For the laser procedure, the following specifications were used for cavity preparation: 4-6 W(330mJ,20Hz). A new bur was used for every five preparations in bur-prepared cavities. Finally, the cavity size was checked using a periodontal probe.
Etching, Bonding, and Filling
The same laser instrument was used for laser etching with following specifications: 0.80 W (80mJ, 10 Hz). For nonrinse etching, a nonrinse conditioner/NRC was used. For self-etch bonding, GC Unifill bond was used. For standard bonding, Prime & Bond/NT was used. Chemical composition and application procedures of the adhesive systems used in this study are shown in [Table 1]. Cavities were restored with compomer resin Dyract Extra, De Trey Gmb H, Konstanz (Germany) according to manufacturers' instructions.
|Table 1: Chemical composition and application procedures of adhesive systems|
Click here to view
After short-term storage in distilled water, parts of the teeth outside of cavity region were coated twice with nail varnish to prevent dying of normal teeth. Then, samples were immersed in 0.5% basic fuchsin and were sectioned longitudinally in buccolingual direction into three sections. Multiple sections were evaluated for dye preparation in each tooth. Digital images were examined and worst scores for both occlusal and gingival margins were used for data analysis. The depth of the cavity walls and dye penetration along occlusal and cervical margins toward the axial wall were determined, and the percentage of dye penetration was calculated. The means of percentage of dye penetration for both interfaces were calculated for each group.
Statistical Package for Social Sciences version 23 was used for the analysis of data. For intergroup comparisons of data, Kruskal-Wallis test was used and built-in pairwise comparison test for Kruskall-Wallis test was used for post hoc analysis. For intragroup comparisons, Wilcoxon signed-rank test was used. P value smaller than 0.05 was used as an indication of statistical significance.
| Results|| |
Microleakage scores (percentages) for all five groups at the occlusal and gingival margins are depicted in [Table 2].
Example images are shown in [Figure 1].
|Figure 1: Two example images showing the scoring of microleakage. Upper image, no microleakage at occlusal or gingival side. Lower image, 64% microleakage at gingival side, whereas no leakage at occlusal site. O, occlusal; G, gingival. Arrows indicate the path of microleakage at gingival side.|
Click here to view
Microleakage scores of gingival margins were higher than those of occlusal margins for all study samples. The difference was statistically significant (P < 0.001).
Occlusal groups had similar microleakage scores with no statistically significant difference between the groups (P = 0.989). There were, however, significant differences between groups in terms of gingival microleakage scores (P = 0.002). Group 4 had significantly higher scores when compared with group 1 (P = 0.049), group 2 (P = 0.031), and group 3 (P = 0.003).
| Discussion|| |
In this in vitro study comparing five different cavity preparation/etching methods with regard to microleakage in Black V cavities of primary teeth, no significant differences in gingival or occlusal locations were found between the majorities of the methods tested; however, a more marked microleakage was observed in cavities in the laser preparation and etching group. Our study represents one of the few studies comparing multiple methods in the setting of primary teeth.,,,,
Self-etch adhesives are commonly preferred due to their ability to eliminate the washing and drying steps, save procedure time, and reduce procedural errors. Therefore, laser and self-etch adhesives were included in the current comparison based on their widespread popularity in modern dentistry. A particular reason for inclusion of the primary teeth in our study was the potential difference in the outcome of restorative procedures between permanent and primary teeth due to differences in morphology and mineral content.
A major issue in adhesive restorations is represented by the lack of proper adhesion to the tooth structure and microleakage between the tooth and filling material. Class V cavities are located in both dentin/cementum and enamel. Studies involving the restoration of cervical lesions using composite resins, glass ionomer cements, or compomers have shown more severe marginal leakage at the gingival margin than occlusal margin., The structural dissimilarity between enamel and dentin has an impact on the adhesion of the filling material to the dental tissues and is one of the determinants of the risk of microleakage. While occlusal surfaces contain higher proportion of enamel with a smoother surface, organic material content of the dentin is higher giving rise to higher susceptibility to potentially adverse effects of dental applications and also leading to differential clinical outcomes as compared with the enamel.,, This is likely to explain the more severe marginal leakage at the gingival margin located in cementum or dentin than that observed at the occlusal margin located in enamel.,, In the study by Sidhu and McCabe  comparing the marginal adaptation of compomers in cervical cavities applied with different bonding agents, greater microleakage along the gingival margin was found than along the occlusal margin, consistent with our observations. Also, presence of adequate enamel tissue was reported to reduce the risk of microleakage in etching procedures.
There has been a recent and growing interest in the use of lasers for routine cavity preparation and for conditioning enamel and dentin surfaces, the latter being used as an alternative to conventional bur and acid-etch methods., Pain, dissonance, and vibration associated with the use of conventional rotary instruments such as diamond burs are generally associated with a significant discomfort in pediatric patients, necessitating the use of anesthesia in many cases. In this regard, laser-based procedures offer certain advantages such as low vibration and low noise during cavity preparation and little or no need for local anesthesia compared to conventional handpiece., Furthermore, as compared to laser-based cavity preparation procedures, conventional rotary instruments such as diamond burs lead to the formation of a smear layer that covers the cavity surface, impacting unfavorably the bonding strength. The current trend in the development of adhesive systems is toward simplification of bonding steps in order to achieve a more user-friendly therapeutic experience. Additionally, reduced number of procedural steps in adhesive systems offers the extra advantage of shortened therapy duration in pediatric procedures. The two-step self-etch primers or single-step self-etching adhesives produce simultaneous conditioning and priming effects on dental substrates. These systems do not remove the smear layer, instead modify it and penetrate the subjacent enamel and dentin, creating a thin hybrid layer dependent on pH, composition, and concentration of polymerizable acids. Casagrande et al. evaluated the cervical microleakage of Scotchbond Multi-Purpose (etch and rinse) and Clearfil SE Bond (self-etch) in occlusoproximal composite restorations of primary molar teeth prepared by bur. They reported that neither of the adhesive systems prevented cervical microleakage. Similarly Baygin et al. reported that none of the adhesive systems tested, i.e., Adper Single Bond2, Scotchbond Multi-Purpose Plus, Xeno III, Clearfil Protect Bond, and Prime&Bond NT, eliminated microleakage completely, with higher microleakage along the gingival margin than along the occlusal margin. In our study, however, there were no significant microleakage differences between different adhesive systems examined (i.e. group 1 vs. group 2 or group 3 vs. group 5).
While similar results in terms of microleakage have been obtained in some previous studies comparing cavity preparation by laser or conventional bur techniques,, others reported worse outcomes for the laser-based procedures., Moldes et al. found significantly lower microleakage in Er:YAG ve Er, Cr;YSGG laser and self-etch groups as compared with etch and rinse adhesive systems. Again Kohara et al. reported less marked marginal leakage in cavities prepared with Er:YAG laser in primary teeth versus those cavities prepared with a conventional high-speed air turbine. Hossain et al. reported that enamel and dentin surfaces treated with Er:YAG laser irradiation were capable of decreasing the microleakage of composite resin restorations. In a study by Ghandehari et al. involving primary teeth, no significant difference in microleakage was found between glass ionomer restoration in Black V cavities prepared by Er:YAG laser or bur techniques.
In the current study, similar results were obtained in groups involving the use of different cavity preparation techniques (group 1 vs. group 3).
However, in this study, use of laser for both cavity preparation and etching resulted in a more unfavorable outcome in terms of microleakage at gingival surface. Laser-induced changes in the surface texture of enamel and dentin have been reported to potentially influence the microleakage in adhesive restorative materials,,, and this influence may vary according to the type, dose, duration, and even angulation of the laser beam. Laser-based applications on dentin tissue cause dentin ablation that fuses collagen fibrils and decreases interfibrillary space; this causes a reduction in resin diffusion into intertubular spaces, with a consequent decrease in intertubular retention leading to microleakage., This may explain the higher occurrence of microleakage in teeth where laser-based cavity preparation and etching was performed in this study.
Certainly, due to the complex nature of the oral cavity, this in vitro result may not accurately reflect in vivo conditions. Another limitation of our study is the inclusion of a small sample size.
The results of this preliminary study suggest that self-etch bonding systems and cavity preparation with Er:YAG laser may be used as an alternative to conventional restoration of primary molars with compomers. However, further studies are warranted to fully elucidate the effect of laser-based etching techniques in cavities prepared by laser.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Baygin O, Korkmaz FM, Arslan I. Effects of different types of adhesive systems on the microleakage of compomer restorations in Class V cavities prepared by Er, Cr:YSGG laser in primary teeth. Dent Mater J 2012;31:206-14.
Guéders A, Geerts S. Relationship between operator skill and in vitro
microleakage of different adhesive systems in Class V restorations. ISRN Dent 2011;2011:285624.
Malekipour MR, Shirani F, Tahmourespour S. The effect of cutting efficacy of diamond burs on microleakage of class v resin composite restorations using total etch and self etch adhesive systems. J Dent (Tehran) 2010;7:218-25.
Hossain M, Nakamura Y, Yamada Y, Kimura Y, Matsumoto N, Matsumoto K. Effects of Er, Cr:YSGG laser irradiation in human enamel and dentin: ablation and morphological studies. J Clin Laser Med Surg 1999;17:155-9.
Borsatto MC, Corona SA, Chinelatti MA, Ramos RP, de Sa Rocha RA, Pecora JD, Palma-Dibb RG. Comparison of marginal microleakage of flowable composite restorations in primary molars prepared by high-speed carbide bur, Er:YAG laser, and air abrasion. J Dent Child (Chic) 2006;73:122-6.
Koshiro K, Sidhu SK, Inoue S, Ikeda T, Sano H. New concept of resin-dentin interfacial adhesion: the nanointeraction zone. J Biomed Mater Res B Appl Biomater 2006;77:401-8.
Bahrololoomi Z, Heydari E. Assessment of tooth preparation via Er:YAG laser and bur on microleakage of dentin adhesives. J Dent (Tehran) 2014;11:172-8.
Baghalian A, Nakhjavani YB, Hooshmand T, Motahhary P, Bahramian H. Microleakage of Er:YAG laser and dental bur prepared cavities in primary teeth restored with different adhesive restorative materials. Lasers Med Sci 2013;28:1453-60.
Ghandehari M, Mighani G, Shahabi S, Chiniforush N, Shirmohammadi Z. Comparison of microleakage of glass ionomer restoration in primary teeth prepared by Er: YAG laser and the conventional method. J Dent (Tehran) 2012;9:215-20.
Kugel G, Ferrari M. The science of bonding: from first to sixth generation. J Am Dent Assoc 2000;131 (Suppl 20):S-25S.
Karaarslan ES, Usumez A, Ozturk B, Cebe MA. Effect of cavity preparation techniques and different preheating procedures on microleakage of class V resin restorations. Eur J Dent 2012;6:87-94.
Corona SA, Borsatto M, Dibb RG, Ramos RP, Brugnera A, Pecora JD. Microleakage of class V resin composite restorations after bur, air-abrasion or Er:YAG laser preparation. Oper Dent 2001;26:491-7.
Sidhu SK, McCabe JF. The adaptation and cavity sealing ability of compomer restorative materials. Am J Dent 2004;17:327-30.
Gagliardi RM, Avelar RP. Evaluation of microleakage using different bonding agents. Oper Dent 2002;27:582-6.
Gutknecht N, Apel C, Schafer C, Lampert F. Microleakage of composite fillings in Er, Cr:YSGG laser-prepared class II cavities. Lasers Surg Med 2001;28:371-4.
Manuja N, Nagpal R. Resin-tooth interfacial morphology and sealing ability of one-step self-etch adhesives: microleakage and SEM study. Microsc Res Tech 2012;75:903-9.
Casagrande L, Brayner R, Sarmento Barata J, Borba de Araujo F. Cervical microleakage in composite restorations of primary teeth-in vitro
study. J Dent 2005;33:627-32.
Khan MFR, Yonaga K, Kimura Y, Funato A, Matsumoto K. Study of microleakage at class I cavities prepared by Er:YAG laser using three types of restorative materials. J Clin Laser Med Surg 1998;16:305-8.
Hossain M, Yamada Y, Nakamura Y, Murakami Y, Tamaki Y, Matsumoto K. A study on surface roughness and microleakage test in cavities prepared by Er:YAG laser irradiation and etched bur cavities. Lasers Med Sci 2003;18:25-31.
Ceballos L, Osorio R, Toledano M, Marshall GW. Microleakage of composite restorations after acid or Er:YAG laser cavity treatments. Dent Mater 2000;17:340-6.
Moldes VL, Capp CI, Navarro RS, Matos AB, Youssef MN, Cassoni A. In vitro microleakage of composite restorations prepared by Er:YAG/Er, Cr:YSGG lasers and conventional drills associated with two adhesive systems. J Adhes Dent 2009;11:221-9.
Kohara EK, Hossain M, Kimura Y, Matsumoto K, Inoue M, Sasa R. Morphological and microleakage studies of the cavities prepared by Er:YAG laser irradiation in primary teeth. J Clin Laser Med Surg 2002;20:141-7.
Delme KI, Deman PJ, De Bruyne MA, De Moor RJ. Microleakage of four different restorative glass ionomer formulations in class V cavities: Er:YAG laser versus conventional preparation. Photomed Laser Surg 2008;26:541-9.
Corona SA, Borsatto MC, Pecora JD, De SA Rocha RA, Ramos TS, Palma-Dibb RG. Assessing microleakage of different class V restorations after Er:YAG laser and bur preparation. J Oral Rehabil 2003;30:1008-1014.
Ceballo L, Toledano M, Osorio R, Tay FR, Marshall GW. Bonding to Er-YAG-laser-treated dentin. J Dent Res 2002;81:119-22.
[Table 1], [Table 2]