Remineralization Potential of a Combination of Chitosan with Nanohydroxyapatite and a Self-assembling Peptide with Nanohydroxyapatite: An In Vitro Study.

AIM: This study explores the demineralizing potential of the combination of chitosan with nanohydroxyapatite (n-HA) and self-assembling peptides with n-HA. MATERIALS AND METHODS: A total of 66 first premolar teeth of similar dimensions extracted for orthodontic purposes were collected for this study. These were then demineralized and randomly divided into the following three groups (n = 22): (i) Control group, (ii) n-HA + Chitosan (HAC), and (iii) self-assembling peptide + n-HA (SP-HA). The samples in each group were brushed every 24 hours with the respective agent. The specimens were stored in Fusayama Meyer's artificial saliva at room temperature and the solution was replenished daily. Mineral content (Ca, P) and surface morphology of the specimens was analyzed, using scanning electron microscopy and energy dispersion X-ray spectroscopy (SEM-EDAX), before demineralization, at 15 days of remineralization and 30 days of remineralization. A two-way analysis of variance (ANOVA) test followed by Tukey's honest significant difference (HSD) post hoc analysis was used to compare the mean elemental composition of the different groups (p < 0.05). RESULTS: There was no significant difference in the calcium (Ca) and phosphate (P) weight percentage between the different groups at the baseline and after demineralization. The Ca and P weight percentages of all three groups after remineralization for 15 and 30 days showed no significant difference from the baseline or after demineralization. The surface morphology after 15 days of remineralization therapy showed decreased surface porosity and increased mineral deposition in the HAC group than the HP-SA group. Surface morphology after 30 days of remineralization showed a more homogenous and smoother surface in the HAC group than the HP-SA group. CONCLUSION: From the results of this study, it can be concluded that the combination of chitosan with n-HA and self-assembling peptides with n-HA can be considered effective demineralizing agents. CLINICAL SIGNIFICANCE: Considering the non-invasive nature of remineralization therapy understanding the effectiveness of different agents is of utmost importance. The demineralizing properties of chitosan, n-HA and self-assembling peptides make their combinations ideal for studying their effectiveness in treating white spot lesions.

Comparative evaluation of the sealing ability of different obturation systems used over apically separated rotary nickel-titanium files: An in vitro study.

AIM: The study was designed to investigate the sealing ability of two obturation systems (cold laterally compacted gutta percha and Obtura II) over different apically separated rotary nickel-titanium files (RACE and K3 system) using dye extraction method. MATERIALS AND METHODS: Sixty-two mandibular premolars were divided into 2 groups of 30 teeth each, and 2 teeth served as negative controls. In Groups A and B, roots were prepared using RACE and K3 system, respectively, and were further subdivided into 4 subgroups. In subgroups A1, B1 and A2, B2 (n = 10 each), files were separated at 3 mm from the tip in apical 3(rd) of the canal. In subgroups A3, B3 and A4, B4 (n = 5), instruments were not separated. Subgroups A1, A3, B1, B3 and A2, A4, B2, B4 were obturated by lateral condensation method and Obtura II techniques, respectively. The sealing ability of the obturated specimens were tested using dye extraction method. The values for each group were recorded and analysis of variance (ANOVA), Student "t" test (two-tailed, independent), and Leven's test were performed. RESULTS: Group A1 showed significantly less leakage than B1. No statistical significant difference between Groups A2 and B2 and Groups A3 and B3, respectively, were observed. Group A4 showed significantly less leakage than B4. CONCLUSION: Groups obturated with Obtura II showed less leakage than the lateral condensation technique irrespective of presence or absence of fractured NiTi rotary system.