Evaluation of Free Available Chlorine of Sodium Hypochlorite When Admixed with 0.2% Chitosan: A Preliminary Study.

AIM AND OBJECTIVE: The aim of the study was to evaluate the changes in free available chlorine (FAC) when 6% sodium hypochlorite (NaOCl) is admixed with irrigants 17% ethylenediaminetetraacetic acid (EDTA), 2% chlorhexidine (CHX), and 0.2% chitosan in varying proportions of 90:10, 80:20, and 50:50. MATERIALS AND METHODS: The 25 mL aliquots of 6% NaOCl were admixed in varying proportions of 90:10, 80:20, and 50:50 with secondary irrigation solutions: (a) 17% EDTA, (b) 2% CHX, (c) 0.2% chitosan. Iodometric titration was done to evaluate the change in FAC. STATISTICAL ANALYSIS USED: Kruskal-Wallis and Mann-Whitney tests. RESULTS: On titration, the mean FAC value of NaOCl at baseline was 1.99 g%. On mixing NaOCl with EDTA, the FAC decreased in all the three proportions and the values were 0.17 g%, 0.17 g%, and 0.06 g% at 90:10, 80:20, and 50:50 ratios, respectively. pH obtained was 9.55 at 50:50 ratio. On mixing NaOCl with CHX, FAC reduced and the values were 1.84 g%, 1.72 g%, and 0.27 g% at 90:10, 80:20, and 50:50 ratios, respectively. pH obtained was 10.87 at 50:50 ratio. On mixing NaOCl and chitosan, the FAC remained unaltered in all the three proportions and the values were 1.64 g%, 1.51 g%, and 1.63 g% at 90:10, 80:20, and 50:50 ratios, respectively. pH obtained was 11 at 50:50 ratio. CONCLUSION: Combination of NaOCl and chitosan did not lead to a reduction in FAC and the pH of the solution remained unaltered, suggesting that tissue-dissolving property of NaOCl might be preserved. CLINICAL SIGNIFICANCE: The combination of chitosan with NaOCl is advantageous in two ways. Firstly, FAC remained unaltered and the pH of the solution was also maintained at 11.05 indicating that the tissue-dissolving property of NaOCl prevailed. Secondly, chitosan is known for its chelating property and is effective in smear layer removal. With further in vivo and in vitro studies, a combination of chitosan and NaOCl can be proposed as a novel irrigant.

Fracture Resistance of Endodontically Treated Roots Restored with Fiber Posts Using Different Resin Cements- An In-vitro Study.

INTRODUCTION: The influence of the remaining coronal tooth structure along with intra-radicular esthetic posts increases fracture resistance of fractured teeth especially in the anterior region. The advent of resin based luting cements improves the adhesion of fiber posts. AIM: To evaluate the fracture resistance of endodontically treated roots restored with fiber posts using different resin cements - Calibra (etch and rinse), PermaFlo® DC (self-etch primer) and SmartCem2 (self-adhesive). MATERIALS AND METHODS: Extracted human maxillary central incisors having similar dimensions were decoronated at the Cemento-Enamel Junction (CEJ) to create 16mm long specimens and endodontically treated. A total of 45 teeth were divided into three groups with 15 teeth each for cementation of easy fiber posts (size1, 0.8mm diameter). Post spaces were prepared to a depth of 10mm. Group 1 - Caulk 34% phosphoric acid gel, dual cure adhesive Prime and Bond NT followed by luting of post with Calibra cement. Group 2 - Ultra - etch then Primer A and Primer B, and PermaFlo® DC was used to cement the post. Group 3 - SmartCem2 [1:1 ratio] was used to cement the post. The excess lengths of posts were seared and teeth were mounted on acrylic blocks and loaded under compressive force to the long axis of the tooth which increased in periodic pattern of 1mm/min. The value of the force at which each root section gets fractured was noted. The data were statistically analysed using ANOVA and Tukey's Test. RESULTS: The mean fracture load (and SD) were as follows Group 1 - 762.400 (251.490); Group 2 - 662.933 (206.709); Group 3 - 657.800 (57.372). No statistically significant differences were seen among all three Groups, p-value (0.228). CONCLUSION: Posts cemented using self -adhesive resin cement SmartCem2 have highest fracture resistance and bonding efficacy of self-adhesive technique showed reliably better results but was comparable to total-etch and self-etch techniques.