Effect of Enamel Pre-etching with Sodium Hypochlorite Deproteinisation and Bonding Agent on Retention and Microleakage of Pit and Fissure Sealants: An In-vitro Study

Abstract

Introduction: Sealants have proved to be one of the easiest methods of caries prevention in young permanent teeth, the placement of which is very technique sensitive. The non-invasive method of pretreating the enamel surface by deproteinising it with 5.25% sodium hypochlorite (NaOCl) for 60 seconds prior to etching has proven to be a promising method for improving retention and reducing microleakage of sealant. Aim: To evaluate the effect of enamel pre-etching with sodium hypochlorite deproteinisation and bonding agent on retention and microleakage of pit and fissure sealants. Materials and Methods: This in-vitro experimental study was conducted in Department of Paediatric and Preventive Dentistry at Annoor Dental College, Muvattupuzha, Kerala and Nanotechnology Lab at Amrita Institute of Medical Science. Freshly extracted Intact permanent maxillary and mandibular 20 third molars and 20 premolars mounted on acrylic blocks were divided into 4 groups containing 5 teeth in each group. Molars and premolar were taken for assessing the rate of retention and microleakage, respectively. Teeth in Group 1 were subjected to acid etching only, Group 2 were deproteinised prior to acid etching, Group 3 were subjected to acid etching followed by bonding and Group 4 were subjected to deproteinisation, etching and bonding. Then, all teeth were sealed with pit and fissure sealant and underwent thermocycling in artificial saliva bath for evaluation of sealant retention and microleakage. After thermocycling, retention was assessed on molar by one pre-calibrated blinded examiner by passing a 0.5 mm diameter probe along the margins of the sealant placed to verify integrity, failure, or loss of continuity based on Simonsen’s criteria (1989). To assess microleakage, premolar samples were immersed in rhodamine B, sectioned longitudinally, and examined under a stereomicroscope for assessment of microleakage. Collected data were statistically analysed using Chi-square and Mann-Whitney u test. Results: The results showed 100% retention for teeth in Group 2a, Group 3a, Group 4a, while partial sealant loss was present in 3 teeth from Group 1a. The differences between the groups for retention was statistically significant (p=0.014). In the case of microleakage, Group 3b showed more microleakage and group 4b showed least microleakage and the difference between them was statistically significant (p=0.009). Conclusion: Deproteinisation and use of bonding agent increases retention of the pit and fissure sealants. However, deproteinisation is a more effective method to control microleakage when compared to bonding agent. Thus, it can be considered as an effective method for pretreating enamel surface before sealant placement.