RESUMEN
OBJECTIVE: To summarize the available clinical evidence on the relative effectiveness of retention of resin-based pit and fissure sealants (PFS) with that of flowable composites on occlusal surfaces of permanent teeth when evaluated in clinical trials. SOURCES: Electronic searches were performed in PubMed and Cochrane Library for the identification of relevant studies, from their inception until February 2020 and an additional search was done with the reference lists of included articles. STUDY SELECTION: The review protocol followed the PRISMA guidelines and was registered in PROSPERO (CRD42018112805). The risk of bias of the studies was independently appraised using the revised Cochrane Risk of Bias tool (RoB 2.0). DATA: Ten articles were considered relevant for qualitative synthesis. The data extracted from two of the included articles showed statistically significant difference between the two materials based on their retention potential, of which one article favored superior retention of flowable composites and one article favored higher retention of PFS and the other eight studies showed no significant difference between the two materials. CONCLUSION: The current review has shown evidence suggesting the effective retention of resin-based pit-and-fissure sealants and flowable composites when applied to prevent occlusal caries in permanent molars, however, this evidence is of low quality. Carefully designed long-term clinical trials are required to support the results of this review. CLINICAL SIGNIFICANCE: This is an important topic that would be of significant interest in the field of preventive dentistry, where sealants are the primary recommended method to prevent caries. The clinical efficacy of sealants is directly linked to their potential to retain and this systematic review focuses on comparing the relative effectiveness of resin-based pit-and-fissure-sealants with flowable composites in permanent teeth.
RESUMEN
INTRODUCTION: It is well-known in the field of endodontics that the presence of a smear layer in the root canals can harbor bacteria and limit the penetration of irrigating solutions and intracanal medications into the dentinal tubules which, in turn, causes the failure of endodontic treatment. Removing the entire smear layer throughout the root canal is essential for the success of endodontic treatment and these chemical agents that facilitate the removal of the smear layer are called chelating agents. Ethylenediaminetetraacetic acid (EDTA), being the most widely used chelating agent, brings about increased reduction in the microhardness of the root dentin, thereby making it friable. N-acetyl cysteine (NAC) is naturally occurring antioxidant that has various beneficial properties for the human being. Several studies have been done in determining the antimicrobial efficacy of NAC against various endodontic pathogens and concluded NAC to be advantageous. The chelating property of NAC has been utilized in heavy metal detoxification, where it binds to the metal ion and removes them from the human system. However, this chelating property has not been explored in the field of endodontics. AIM: This study was aimed to compare the ability of N-acetyl cysteine with the conventional chelating agent in the removal of the smear layer and in altering the microhardness of root dentin. MATERIALS AND METHODOLOGY: A total of 84 single-rooted human mandibular premolars with relatively similar dimension and morphology, freshly extracted with closed apices, were collected from adult patients. The crowns of all specimens were cut transversally at the cementoenamel junction (CEJ) with the double-faced diamond disc at low speed, with water coolant, to obtain a 12 mm root length. The root canals were randomly divided into three equal groups according to the final irrigation solutions: Group I: 17% EDTA, Group II: 20% NAC, and Group III: distilled water (control). They were then randomly divided into two parts: scanning electron microscope (SEM) analysis for the extent of smear layer removal and microhardness evaluation using the Vicker's hardness test. RESULTS: The smear layer removal ability of EDTA and NAC were more effective in the coronal and middle thirds of the root canal. However, both groups showed less smear layer removal in the apical region. Specimens treated with distilled water showed the least reduction in the smear layer throughout the length of the root canals. Regarding the evaluation of microhardness, both EDTA and NAC had a significant reduction in root dentin microhardness. However, the percentage of dentin microhardness reduction was significantly more in the EDTA group (p < 0.05) than N-acetyl cysteine in the coronal, middle, and apical third of the root canals. CONCLUSION: The chelating property of NAC is equally effective to that of EDTA in the smear layer from the root canal, and it induced a significantly lesser reduction in microhardness of root dentin than EDTA.