|Year : 2014 | Volume
| Issue : 1 | Page : 16-21
The evaluation of different methods viz., acid etch and by air abrasion on retentivity of fissure sealant after 6 months: A clinical study
P. V. Ravindranath Reddy1, Shivayogi M Hugar1, Shobha D Deshpande2, Anand Shigli3, Dayanand Shirol1, KS Poonacha1
1 Department of Pedodontics and Preventive Dentistry, KLE VK Institute of Dental Sciences, Belgaum, Karnataka, India
2 Department of Pedodontics, Yerala Dental College, Navi Mumbai, Maharashtra, India
3 Department of Pedodontics, Bharati Vidyapeeth Dental College, Sangli, Maharashtra, India
|Date of Web Publication||7-Feb-2014|
P. V. Ravindranath Reddy
Department of Pedodontics and Preventive Dentistry, KLE VK Institute of Dental Sciences, Nehru Nagar, Belgaum - 590 010, Karnataka
Source of Support: None, Conflict of Interest: None
Background and Purpose: The objectives of the study were (1) to compare two techniques of sealant placement using Acid-etch technique and by using an Air abrasive technique, (2) to determine whether particular tooth locations are related to sealant loss or retention. Methodology: 30 children in age group 7-12 years were received sealant on non carious, non filled, occlusal, and buccal pit surfaces of both permanent first mandibular molars (36, 46) two in each subject of treatment groups: 1) Acid etch technique (Group A) and 2) Air abrasion without acid etch (Group B). A total of one hundred and twenty surfaces received sealants, and were evaluated at six months. Results: Rate of complete sealant retention at six months for occlusal surfaces were 89.29% for Acid etching and 78.57% for Air abrasion , and for buccal surface were 50% for Acid etching and 32.14% for Air abrasion. Conclusion: This study suggested that, rates of complete retention on the occlusal and buccal surfaces of both treatment groups were not significant. More research is needed to identify factors contributing to low retention rates on occlusal and buccal surfaces for Air abrasion technique.
Keywords: Acid etch, air abrasion, pit and fissure sealant, retention
|How to cite this article:|
Reddy PR, Hugar SM, Deshpande SD, Shigli A, Shirol D, Poonacha K S. The evaluation of different methods viz., acid etch and by air abrasion on retentivity of fissure sealant after 6 months: A clinical study. J Sci Soc 2014;41:16-21
|How to cite this URL:|
Reddy PR, Hugar SM, Deshpande SD, Shigli A, Shirol D, Poonacha K S. The evaluation of different methods viz., acid etch and by air abrasion on retentivity of fissure sealant after 6 months: A clinical study. J Sci Soc [serial online] 2014 [cited 2019 Jul 18];41:16-21. Available from: http://www.jscisociety.com/text.asp?2014/41/1/16/126709
| Introduction|| |
Despite diligent oral hygiene procedures, optimal fluoride environment and a realistic approach to dietary modifications, occlusal caries is inescapable for most children and adolescent as a result of the anatomy of the pit and fissure surfaces, which favors stagnation of bacteria and substrates. Some fissures are well-fused, coalesced and these are less susceptible to decay. Other fissures, however cannot be cleaned as they are narrower than even a single bristle of a tooth brush. The latter fissures are ideal sites for colonization by cariogenic bacteria and subsequent demineralization of the enamel leading to caries. 
The extreme vulnerability of dental decay of occlusal surface has prompted dental sciences to seek methods of caries prevention, especially for pit and fissures. The culmination of these efforts has resulted in the current technique of occlusal sealing. The cariostatic properties of sealants are attributed to the physical obstruction of the pits and fissures. This prevents the penetration of fermentable carbohydrates and so the remaining bacteria cannot produce acid in cariogenic concentration 
The need for the special protection by the sealant for occlusal surfaces soon after the eruption is an appropriate measure in preventing dental caries. Sealants are effective caries preventive agents to the extent they remain bonded to teeth. The longevity of sealant cover i.e., clinical retention is considered to be the measure of sealant success. The prerequisite for retention is that enamel surface must be modified either with an acid condition or by the air abrasive method. 
Concern has been expressed that the traditional acid etching technique for sealant placement does not allow for complete cleaning of the pits and fissures prior to sealant placement. This may lead to entrapment of organic plug material, which could become problematic if sealant wear over time re-exposes these areas to the oral environment. Concern has also been expressed that the traditional acid etch technique for sealant placement can lead to inadvertent sealing over the undiagnosed caries. 
A new method for sealant application using air abrasive technology is less technique sensitive eliminates several steps necessary in the traditional technique and therefore may reduce working time. Air abrasion allows for total cleaning of the grooves prior to sealant placement. The abrasive particles used in air abrasion effectively remove organic plug material from the fissures and allow for deeper penetration of the sealant material into the fissures and may be able to help in reducing caries. 
Though the use of an acid solution to etch an enamel surface is an essential prerequisite for the successful bonding for the resin to the tooth surface, the comparison between these two methods i.e., with acid etching and air abrasion needs to be studied to evaluate retentivity of the pit and fissure sealant.
| Objectives|| |
The purpose of this in vivo study was:
- To compare two techniques for sealant placement of fissure sealant with acid-etch technique and using an air abrasion technique.
- To determine whether particular tooth locations are related to sealant loss or retention.
| Materials and Method|| |
The study was conducted on 60 sound first permanent mandibular molars of 30 children between the age group of 7-12 years. These subjects were selected from the patients attending for the dental treatment at the Department of Pedodontics and Preventive Dentistry, K.L.E.S's Institute of Dental Sciences, Nehru Nagar, Belgaum, Karnataka.
The procedure were explained fully to the parents of children involved in the study and their informed consent as approved by the head of the institution and as well as permission of ethical committee was obtained from the institutional ethical committee prior to the investigation on a special format and also permission for publication was also obtained.
Children received a screening dental examination and 30 were considered eligible for the sealant study. As only first permanent molars were sealed in the mandible the number of teeth sealed per eligible participant were two. Fissure morphology may vary widely between the different types of teeth. Teeth with centralized fissure system throughout the occlusal table were chosen for standardized system.  The selected cases were confirmed for the absence of dental caries with caries detector.
The teeth under study in case of selected children were chosen who required minimum two pit and fissure sealants in either arch or same arch preferably each on the opposite side (i.e., right and left). The teeth on the right side are assigned to the acid etching (Group A) and the left side for the air abrasion (Group B) respectively. Two discrete surfaces per tooth were eligible for sealant placement viz. the occlusal surface and the buccal surface. The total number of surfaces per eligible participant was four (two surfaces on each tooth). The protocol for sealant placement was as follows.
Each child was asked to "dry brush" his/her teeth while waiting for sealant placement. Permanent first left mandibular molar was isolated with rubber dam [Figure 1]. Tooth was thoroughly cleaned with prophylaxis cup, using pumice and water for 10 s then the tooth was rinsed well and dried lightly with oil free compressed air [Figure 2]. To this isolated tooth surface, 38% phosphoric acid etching gel (Etch-rite) [Figure 3] was applied to the occlusal pit and fissure and buccal groove/pit and fissure for 15 s. Then the tooth was rinsed for 10 s. Excess water was removed and tooth surface was dried completely with a cotton pellet.
|Figure 1: Photograph showing the pre-operative view suitable to receive fissure sealant|
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|Figure 2: Photograph showing cleaning of the teeth with slurry of pumice and water|
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|Figure 3: Photograph showing acid etching with 38% phosphoric acid on occlusal surface and the buccal surface|
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A light curing pit and fissure sealant (Embrace-wet bond) [Figure 4] was applied to occlusal/buccal using a syringe applicator as supplied by the manufacturer. Excess sealant was removed with an explorer. Then it was light cured for 20 s with curing light. After polymerization, sealant was examined with the explorer to check the retention of the sealant. Rubber dam was removed and occlusion was checked with articulating paper.
|Figure 4: Application of embrace sealant on slightly moist occlusal and buccal surfaces|
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The protocol for selection and sealant placement using the air abrasive technique (Group B) is as follow.
Each child was given similar instructions as it was given for acid etch (Group A) technique. Tooth was thoroughly cleaned with prophylaxis cup, using pumice and water for 10 s then the tooth was rinsed well and dried lightly with oil free compressed air. Surface to be sealed (occlusal pit and fissure, buccal groove/pit) were air abraded using the air sonic mini-sand blaster [Figure 5] with 50 μm alpha alumina particles at 80 psi for 15 s, then the tooth surface was slightly moisted with cotton (wet) pellet. This moist surface appeared shiny or glossy. To this glossy surface a light-curing pit and fissure (Embrace-wet bond) was applied using a syringe applicator as supplied by the manufacturer. Excess sealant was removed with an explorer. Then the light exposure was carried out for 20 s with QHL 75 curing light [Figure 6].
|Figure 5: Photograph showing preparation of the pit and fissures on occlusal and buccal surfaces with air abrasion system with 50 mm alumina powder|
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|Figure 6: Photograph showing curing the sealant material on occlusal and buccal surfaces|
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After polymerization, sealant was examined with the explorer to check the retention of the sealant. Rubber dam was removed and occlusion was checked with articulating paper.
All follow-up examinations were conducted using a dental chair, a head lamp, mirror and explorer. Sealant placed as part of this clinical trial were classified as either completely present [Figure 7], partially present [Figure 8] or completely missing, using criteria described by Simonsen.  Occlusal and buccal pit surfaces were scored separately.
To test whether the retention depends on the position, χ2 test with Yate's correction was applied. The test of proportion was applied to see the significant difference between the proportions of retentivity of Group A and Group B.
| Results|| |
Of 30 subjects, 28 (i.e., 93.3%) were available for the evaluation of sealant retention after 6 months. Two subjects were not available for 6-month evaluation due to demographic reasons. The frequency distribution of percentage of sealant retention of the acid etching (Group A) and air abrasion (Group B) for the occlusal surfaces. Out of 28 surfaces observed with acid etch (Group A) 25 were found to be totally retained giving 89.29%. However within the Group A from one occlusal surface fissure sealant was completely missing. In this group partially retained, completely missing were negligible and it amounted to total of 3 surfaces out of 28 surfaces observed. In Group B, total number of retention of sealant on occlusal surfaces 22 (78.57%), partially retained surfaces 6 (21.43%) and completely missing zero (0%) respectively [Table 1].
|Table 1: Retention of sealant by acid etch technique (Group A) and air abrasion (Group B) (occlusal surface) |
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Retention of the sealant by acid etch technique (Group A) and air abrasion (Group B) for buccal surfaces showed 39.29% surfaces completely missing in the Group A as compared with 60.71% in air abrasion (Group B) [Table 2].
|Table 2: Retention of sealant by acid etch technique (Group A) and air abrasion (Group B) (buccal surface) |
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Chi-square test for independence for occlusal surfaces and buccal surfaces in acid etch (Group A) was 11.6359 and air abrasion (Group B) was 24.45161. "P" < 0.01 indicating dependence of retention and the position in Group A and Group B, respectively [Table 3].
|Table 3: Chi-square test for independence for occlusal surfaces and buccal surfaces in acid etch (Group A) and air abrasion (Group B) |
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Z value for occlusal surfaces pertaining to acid etching (Group A) and air abrasion (Group B) for totally retained, partially retained, completely missing (P ≥ 0.05) were 1.6916, 1.5275, 1.0090 respectively, which were not statistically significant [Table 4]. Z value for buccal surfaces pertaining to acid etching(Group A) and air abrasion (Group B) for totally retained, partially retained, completely missing (P ≥ 0.05) were 1.3581, 0.4686, 1.6036 respectively, which were not statistically significant [Table 5].
|Table 4: Z values and P values proportion for the occlusal surfaces in acid etch (Group A) and air abrasion (Group B) |
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|Table 5: Z values and P values in the test of proportion for the buccal surfaces in acid etch (Group A) and air abrasion (Group B) |
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| Discussion|| |
The success of the pit and fissure depends upon the retentivity of the material. The long-term retentivity further depends upon the adhesion of the material to the tooth enamel. However, the different types of materials selection of the tooth (anatomical structure of fissures), the position of the tooth in the mouth, the skill of the operator, the age of the child, the eruption status of the tooth and method of application also affects the clinical success of the sealants.
The longevity of the pit and fissure sealant is critical to its preventive effectiveness. The retention of dental sealant to the prepared tooth surface is critical to place the sealant. The comparison of acid etching technique (Group A) and air abrasion (Group B) on the retentiveness of fissure sealant was observed. This particular comparison was taken into consideration as concern has always been expressed in literature about the traditional acid etch technique for sealant placement, which is known for not to allow complete cleaning of the pit and fissures prior to the sealant placement. ,
The magnitude of the occlusal caries reduction is a function of the sealant's ability to remain firmly adherent to the tooth. The prerequisite for retention is that the enamel surface be modified either with acid conditioning agent or some other technique like air abrasion. 
For this in vivo study, 30 paired permanent right and left mandibular first molars (36, 46) were evaluated at 6 months. Mandibular teeth were selected as literature demonstrates that lesser amount of sealant loss is evaluated in these molars. 
Any proposed treatment for reduction of dental caries, caries prevention must be effective for molars since they have higher caries risk for children at this age considered in the present study than any other type of teeth. 
Overall observation of results do confirm that acid etch technique was more effective when compared with totally and partially missing surfaces within these groups around three in the Group A as compared with six within air abrasion (Group B). Completely or partially loss of this six surfaces (Group B) can be attributed to inadequate modification of enamel on the surface resulting in insufficient irregularities for the sealant retention. 
Overall retention of sealant was much lower in acid etch as well as air abrasion group for buccal surfaces. Similar results were observed by Kanellis et al. 1997. However in their study retention rates for buccal and distolingual surfaces were much lower for the air abrasion group than the acid etch group. 
Air abrasion achieves its retention through the mechanical/physical retention of the surface enamel. These alteration in enamel is achieved by air abrasion microscopically is not as same as for the acid etch and may not have optimal mechanical retention properties. However in the present study, air abrasion did show its ability to retain sealants with 78.57% on occlusal as compared with 32.14% on the buccal surface. This depicts an advantageous property and its ability to remove the stain and organic material in the pit and fissures. 
The possible explanation given for the lower retention rate on buccal surfaces could be related to inadequate modification of enamel on the surface resulting in insufficient irregularities. It is difficult to compare the findings of this study especially for the retention rates on the buccal surface.
χ2 values of 11.6359 (P ≤ 0.01) for Group A and 24.4516 (P ≤ 0.001) indicating dependence of retention, which can be attributed to fissure morphology and the fissure depth and not on the technique used.  More research is needed to understand and improve the air abrasion applications. It does not appear that air abrasion technology is at a significant advantage over the traditional sealant placement method by acid etch technique. Complete understanding of the parameters that affect the quality of the methodology is needed so that the clinicians using this system can produce the desired results.
| Conclusion|| |
Though this study assessed the differences in the retentivity produced with acid etch (Group A) and air abrasion (Group B), which shows statistically not significant results. An attempt has been made to perform the quantitative basis of available data and only tentative conclusion can be offered. However, further detailed studies will be required with constant revision in the light of the changing pattern of dental caries experienced in the population and of newer developments in the dental materials. However, more research is needed with respect to air abrasion application toward microleakage and qualitative retentivity of the sealants.
| Acknowledgments|| |
We would like to acknowledge Dr. Roshan N. M, Dr. Varun Sardhana.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]