|Year : 2010 | Volume
| Issue : 3 | Page : 145-150
Flowable resin used as a sealant in molars using conventional, enameloplasty and fissurotomy techniques: An in vitro study
TR Chaitra1, VV Subba Reddy2, GM Devarasa3, TL Ravishankar4
1 Senior Lecturer, Department of Pedodontics and Preventive Dentistry, Kothiwal Dental College and Research Centre, Kanth Road, Moradabad - 244 001, Uttar Pradesh, India
2 Professor and Head, Department of Pedodontics and Preventive Dentistry, College of Dental Sciences, Davangere - 577 004, India
3 Senior Lecturer, Department of Pedodontics and Preventive Dentistry, College of Dental Sciences, Davangere - 577 004, India
4 Reader, Department of Community Dentistry, Kothiwal Dental College and Research Centre, Kanth Road, Moradabad - 244 001, Uttar Pradesh, India
|Date of Web Publication||11-Dec-2010|
T R Chaitra
Department of Pedodontics and Preventive Dentistry, Kothiwal Dental College and Research Centre, Kanth Road, Moradabad - 244 001, Uttar Pradesh
| Abstract|| |
Background and Objective: Preventive procedures using pit and fissure sealants are one of the most important aspects of pediatric dental practice. The objectives of this in vitro study were to comparatively evaluate microleakage of a flowable resin used as a sealant on molars after preparation with conventional, enameloplasty and fissurotomy techniques. Materials and Methods: A total of 24 teeth were divided into three groups of eight samples each. Pits and fissures were prepared with conventional sealant technique (CST) (Group A), enameloplasty sealant technique (EST) (Group B) and fissurotomy technique (FT) (Group C). Following sealant placement, thermocycling and sectioning of samples of Groups A, B and C were performed and microleakage was assessed under a stereomicroscope after methylene blue dye immersion. Results: There was significantly lesser microleakage in EST when compared with CST and FT, which showed more microleakage. No statistical significance between CST and FT was found. Interpretation and Conclusion: EST has proven to be an excellent method of preparation of pits and fissures when flowable composite is used as a sealant because of its lesser microleakage.
Keywords: Conventional sealant technique, enameloplasty sealant technique, fissurotomy technique, microleakage
|How to cite this article:|
Chaitra T R, Subba Reddy V V, Devarasa G M, Ravishankar T L. Flowable resin used as a sealant in molars using conventional, enameloplasty and fissurotomy techniques: An in vitro study. J Indian Soc Pedod Prev Dent 2010;28:145-50
|How to cite this URL:|
Chaitra T R, Subba Reddy V V, Devarasa G M, Ravishankar T L. Flowable resin used as a sealant in molars using conventional, enameloplasty and fissurotomy techniques: An in vitro study. J Indian Soc Pedod Prev Dent [serial online] 2010 [cited 2013 May 19];28:145-50. Available from: http://www.jisppd.com/text.asp?2010/28/3/145/73786
| Introduction|| |
The age-old G.V. Black's theory of EXTENSION FOR PREVENTION is seldom followed; rather, in operative care, RESTRICTION WITH CONVICTION or PREVENTION OF EXTENSION is popularly practiced. Natural enamel and dentin are still the best "dental materials" in existence; therefore, restorative techniques that conserve a greater part of the natural, healthy tooth structure were considered desirable. Pit and fissures are recognized as being highly susceptible to caries. Despite the declining caries rate suggested by current research, the prevalence of occlusal surface remains quite high.  The susceptibility of occlusal surfaces to caries has often been related to the morphology of pits and fissures on these surfaces.  Factors responsible for the high incidence of occlusal caries include the lack of salivary access to the fissures as a result of surface tension, effectively preventing remineralization and reducing the effectiveness of fluoride. , Sealing pits and fissures in teeth is a widely advocated preventive technique. A nagging issue is identification of the ideal technique for placement of sealants to maximize retention and prevent microleakage. Fortunately, the current era of dentistry brought with it new materials, techniques and instruments that make conservative dentistry practical and ultraconservative dentistry a reality.  Enameloplasty or fissure enlargement with a bur has been advocated as a technique that enhances retention by allowing deeper penetration of etchant and sealant and increasing surface area for bonding.  The clinical behavior of adhesives and composite materials for dental restorations has significantly improved compared with previously used materials. The applicability of flowable restorative systems in dentistry has increased mainly because of their beneficial properties, such as low viscosity, low modulus of elasticity and ease of handling. This allows the materials to be placed, even in ultraconservative preparations. Flowable composite materials have better abrasion resistance and, thus, provide a better retention than a conventional unfilled resin. ,
However, major concern and studies are being performed to evaluate the effect of the additional techniques that include fissurotomy and enameloplasty and bonding agents that make the pits and fissures conducive to receive a flowable resin. The aim of the study is to compare and evaluate the microleakage of flowable composite used as a sealant after preparation of pits and fissures with conventional, enameloplasty and fissurotomy techniques.
| Materials and Methods|| |
A total of 24 mandibular molars were used in the study. The samples were thoroughly cleaned to free them of debris and calculus using scalers and were stored in distilled water until experiment time. The teeth were randomly distributed into three groups of eight teeth each.
Group A: Conventional technique: Pumice prophylaxis, rinse, dry and acid etching for 40 s with 37% phosphoric acid was performed followed by rinse and dry.
Group B: Enameloplasty technique: Saucerization of the pits and fissures was carried out using round tungsten carbide bur under low speed followed by acid etching for 40 s with 37% phosphoric acid, rinse and dry.
Group C: Fissurotomy technique: A fissurotomy bur (micro short tapered fissure, SS WHITE, USA) was used to open up the fissures with the small head size. The pits and fissures were prepared to the size of the bur head, followed by acid etching for 40 s with 37% phosphoric acid, rinse and dry.
The etched teeth surfaces in all the groups were bonded with Tetric-N-Bond (Ivoclar Vivadent) adhesive and cured for 20 s, which was followed by the placement of flowable composite (Filtek Z350) as a sealant as per the manufacturer's instructions.
Roots of the molar samples of all the groups were cut from the crowns using a high-speed water-cooled diamond blade. The samples were placed in distilled water at 37 0 C for 24 h and then the samples were subjected to thermocycling for 200 cycles between 2 0 C and 58 0 C with a dwell time of 15 s and a 15-s transfer time to simulate temperature fluctuations found in the oral cavity. The samples were coated with a nail varnish on the tooth surfaces, except on the restoration and 1-mm rim of tooth structure around the restoration (window), and were immersed in 2% methylene blue dye for 48 h. Following removal of samples from the dye, they were rinsed in tap water for 5 minutes to remove excess dye and were mounted mesiodistally on the acrylic block measuring 1 in × 1 in (diameter × length), exposing half the tooth structure. The teeth were sectioned labiolingually across the center of the tooth using a hard tissue microtome.
Dye leakage score
The samples were then examined under a stereomicroscope (x16) magnification to analyze dye penetration at the marginal seal of the flowable composite.
0 - No dye penetration.
1 - Dye penetration up to 1/3 of the depth of the fissure.
2 - Dye penetration more than 1/3 and less than 2/3 of the depth of the fissure.
3 - Dye penetration more than 2/3 of the depth of the fissure.
The statistical softwares, namely SPSS 11.0 and Systat 8.0, were used for analysis of the data and Microsoft Word and Excel were used to generate graphs, tables etc. Because the microleakage was assessed in scores, non-parametric tests were used for analysis. Results are expressed as mean ± SD. The Kruskal-Wallis ANOVA was used for multiple group comparisons and Mann-Whitney U-test was used for group-wise comparisons. For all the tests, a P-value of 0.01 or less was used for statistical significance.
| Results|| |
This in vitro study was carried out to evaluate and compare the microleakage of flowable composite used as a sealant after conventional, enameloplasty and fissurotomy techniques.
The degree of marginal leakage was evaluated by the penetration of the dye stain from the occlusal margin to the base of the fissure. After the longitudinal sectioning of the teeth, the teeth were examined under a stereomicroscope and scores were given accordingly [Figure 1],[Figure 2],[Figure 3],[Figure 4].
[Table 1] shows the comparison of the three groups regarding their range value, median values, mean and standard deviation.
The mean score of Group A was 1.75 and SD was ±0.89. The median score was 1.5 whereas their range was between 1 and 3.
The mean score of Group B was 0.5 and SD was ±0.53. The median score was 0.5 whereas their range was between 0 and 1.
The mean score of Group C was 1.5 and SD was ±0.53. The median score was 1.5 whereas their range was between 1 and 2.
[Table 2] shows the comparison of mean microleakage scores between the test groups. Group A and Group B and Group B and Group C show statistically significant differences, with a P-value of <0.01. But, there was no statistically significant difference between Group A and Group C.
| Discussion|| |
Dental caries has been decreasing around the world over the last two decades, this having been associated largely with the use of fluoride in different forms, because of its protective effect mainly on smooth surfaces, but dental caries associated with occlusal surface still persists. Pit and fissures are recognized as being highly susceptible to caries. Fissure sealing or use of fissure sealants with unfilled resin or resin composites after acid etching of the enamel has been advocated as a reliable method for prevention of fissure caries. Excellent retention and longevity of sealants depend on three factors: penetrability of the acid-etched enamel, marginal sealing and wear and abrasion resistance. The clinically undetectable passage of bacteria, fluids, molecules or ions between the cavity wall and the applied restorative material is known as microleakage, which is an important concern in restorative dentistry because of its clinical damages such as secondary carious lesions, pulpal pathologies, post-operative pain and sensitivity and, consequently, failure of the restorative procedure. In the case of pit and fissure sealants, the success can be hindered if the applied material cannot resist microleakage, resulting in the initiation and/or progression of caries under sealed surfaces as well as increasing the difficulty of diagnosing and treating this lesion. The quest for a perfect sealant is a real challenge; although bond strength is important, microleakage is very important. In fact, in the presence of any microleakage, the anticariogenic properties of the sealant are jeopardized and a caries process may begin underneath the sealant. Consequently, microleakage is the main factor that affects the sealant efficiency. Therefore, the present study was undertaken to evaluate the microleakage of a flowable composite that was used as a sealant after different techniques of preparing the fissures, viz conventional, enameloplasty and fissurotomy techniques. Because the technique of fissure preparation increases the surface energy, this seems to be of major importance in the success of sealant  fissure preparation, which was emphasized in this study. For adequate adaptation of the sealant, removal of plaque, pellicle and other contaminants that inhibit the dispersion of sealant and also inhibit the ability of sealants to closely contact enamel is important.
In the present study, comparison was made between three fissure preparation techniques. Conventional sealant technique (CST), wherein pumice prophylaxis of the fissures was done followed by acid etching and sealed with flowable composite and results have shown greater microleakage in the CST group compared with the enameloplasty sealant technique (EST). Chan et al. showed that from the micromorphological stand point, prophylaxis with pumice and a pointed bristle brush or rubber cup is less effective than other preparation methods. Pumicing removes only organic material on smooth enamel surfaces and is unable to clean enamel walls of fissures,  whereas Blackwood and Dilley reported that there was no statistical significant difference in microleakage when sealant was placed after pumice prophylaxis, bur preparation and air abrasion preparation methods in combination with acid etching. 
The possible explanation for the greater microleakage in pumice prophylaxis is that a rubber cup or pointed bristle brush with pumice did not adequately clean pits and fissures to allow the etchant to produce a surface area receptive for bonding when compared with other methods that increased the surface area thus increasing the adaptability of the sealant. 
The other group that was evaluated in present study was EST, where round bur was used in low speed for saucerization of the pits and fissures followed by acid etching and were sealed with flowable composite. The results have shown very minimal microleakage, and it was significantly less when compared with the other groups.
The main aim of EST was to remove the debris, acquired pellicle and opening up the fissures and also increasing the surface area because an increased surface area will enhance sealant retention thus decreasing microleakage.
Kofmann et al. compared fissure preparation with different methods and reported that bur preparation with Ό round bur coupled with acid etching was significantly better at reducing microleakage when compared with prophylaxis and acid etching.  Geiger et al. demonstrated that the deeper the level of sealant penetration, lower the probability of microleakage and enameloplasty, providing deeper sealant penetration and less microleakage. 
The probable reason for decreased microleakage in EST is that, by enlarging the narrow fissures, the sealant easily penetrates and also eliminates the acquired pellicle thus increasing the sealant adaptability. Salama and Al-Hammad evaluated the quality of marginal seal and fissure penetration of a resin-sealant (concise) and a compomer restorative material with or without enameloplasty and reported that the microleakage was similar when sealant with acid etching and compomer with acid etching and bonding agent are used without enameloplasty and also marginal gap was more evident in the compomer group with bonding agent and without enameloplasty. Enamel fissure penetration of sealant was better when enameloplasty and acid etching were used, which showed subsequently lesser microleakage.
The other fissure preparation technique that was used in this study was the fissurotomy technique (FT), wherein the fissures were enlarged in the shape and size of the head of the Short Tapered Fissurotomy bur (S. S. White), which was acid etched and sealed with flowable composite. Results have shown that significant microleakage occurred in this group when compared with EST, but was similar to CST.
Freedman et al. reviewed on ultraconservative resin restorations and have reported that the typical fissurotomy preparation is very narrow, long and irregularly deep, and it is important that the restorative material should flow easily into all the nooks and crannies. The material of choice is a flowable composite but, in very deep fissures, significant microleakage was observed. 
Acid etching is an important step that aided better sealant adaptability and decrease in microleakage. Lupi-Pegurier et al. observed microleakage of pit and fissure sealant after preparation with Sono-abrasion, used alone or associated with acid etching, and reported that acid etching produced microscopic porosities in the enamel that increased the surface area of the fissure into which sealant was flown, which hardens in tag-like projections that attach the material to the surface of tooth thus decreasing the microleakage. Conditioning the surface enamel with phosphoric acid is now the standard method for preparing the enamel surface. 
Gungor et al. evaluated the use a flowable polyacid modified resin composite as fissure sealant on air-abraded permanent teeth after acid etching and/or bonding agent application and reported that applying acid etching and bonding agent prior to the application of fissure sealant considerably reduced microleakage.
It has been observed in the present study that some amount of microleakage was found in all the groups, lesser in enameloplasty and significantly more in conventional and FT techniques. This can be attributed to the property of the flowable composite, which shows some amount of polymerization shrinkage following light curing, that may create microgaps between tooth and flowable composite, which has been implicated to contribute to microleakage.
Duangthip et al. compared classical sealants, flowable composite and flowable compomers and reported that classical sealants showed significantly lower microleakage compared with flowable composite and flowable compomers. The reasons for greater microleakage were the nature of shrinkage that might affect the quality of sealing and also the use of bonding systems in combination with flowable composite, which might be another crucial step toward influencing the bond quality of sealants; thus, affecting microleakage. High-modulus composites generally produced high shrinkage stresses during polymerization. 
The other reason for the presence of microleakage in all the groups is the process of thermocycling, which was performed by tempering of samples at temperatures of 2 0 C and 58 0 C to simulate the oral conditions. Hannig et al. reported that the fissure sealant placed after acid etching provided tight seal, but due to thermocycling, loss of sealing ability could be detected. Theodoridou-Pahini et al. reported that increased degree of microleakage occurs in the thermocycled specimens compared with those of non-thermocycled specimens, and also reported that the thermal expansion coefficient of the sealants is significantly different from that of the enamel and the mechanics of expansion and contraction of the teeth are different from those of materials; thus, affecting microleakage. 
Further studies testing the flowable composite and the different preparation techniques in vivo are warranted to determine whether the amount of microleakage is the same as in the in vitro study and whether the observed amount of microleakage, if present, is clinically relevant.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2]