Comparative evaluation of remineralization potential of nanohydroxyapatite crystals, bioactive glass, casein phosphopeptide-amorphous calcium phosphate, and fluoride on initial enamel lesion (scanning electron microscope analysis) - An in vitro study.

AIM: The aim of this in vitro study was to evaluate and compare the remineralization potential of four different remineralizing agents, i.e., nanohydroxyapatite crystals, bioactive glass, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), and fluoride on initial enamel lesion. MATERIALS AND METHODS: Sixty human maxillary central incisors were used in the present study. Samples were randomly divided into four groups (n = 15). Group 1: nanohydroxyapatite-containing dentifrice (Acclaim); Group 2: bioactive glass containing-dentifrice (SHY-NM); Group 3: CPP-ACP-containing dentifrice; and Group 4: fluoride-containing dentifrice. Baseline microhardness was checked, followed by immersion of teeth samples in demineralizing and remineralizing solution. This was followed by a pH cycle of 10 days. Data were analyzed using ANOVA and Bonferroni method. After this, scanning electron microscopic analysis was done to evaluate remineralization. RESULTS: Statistical analysis of data was conducted using ANOVA, and multiple comparisons within groups were done using the Bonferroni method (post hoc tests). The decision criterion was to reject the null hypothesis if P < 0.05. If there was a significant difference between the groups, multiple comparisons (post hoc test) using the Bonferroni test were carried out. CONCLUSION: There is a significant difference in mean microhardness between the groups after remineralization. The mean value was found to be highest for nanohydroxyapatite, bioactive glass, CPP-ACP, and fluoride in descending order.

Efficacy of rotary and reciprocating single-file systems on different access outlines for gutta-percha removal in retreatment: An in vitro study.

INTRODUCTION: The aim of this study is to compare the effectiveness of reciprocating and continuous rotary nickel-titanium instruments during retreatment performed through two different access outlines. METHODOLOGY: A total of 48 freshly extracted mandibular first and second premolars with single root and canal were selected. Initial root canal treatment was completed through a contracted endodontic cavity (CEC) design. Canals were instrumented with F2 ProTaper instrument, obturated with warm lateral condensation of gutta-percha with AH Plus sealer, and allowed to set for 30 days at 37°C and 100% humidity. For retreatment, specimens were divided into two groups (n = 24) on the basis of access outline, CEC or traditional endodontic cavity. Retreatment was initiated using ProTaper Retreatment instruments (D1-D3). Specimens were further divided (n = 12) and reinstrumented up to Neoniti 25/0.08 or WaveOne 25/0.08. Irrigation was performed using 3% sodium hypochlorite and 17% ethylene diamine tetraacetic acid. Retreatment time was recorded. Teeth were sectioned and photographed, and the percentage of remaining obturation material was measured. RESULTS: Data were collected, and statistical analysis was performed using one-way analysis of variance and Tukey honestly significant difference multiple post hoc procedures (P < 0.05). CONCLUSION: None of the systems completely removed the root filling material from root canals. However, ProTaper/Neoniti instruments removed more GP when compared to Protaper/WaveOne instruments with both the access outlines. Both the instruments with traditional access outline required less time for removal of obturating material when compared to CEC.

Cone-beam computed tomography assessment of root canal transportation using WaveOne Gold and Neoniti single-file systems.

INTRODUCTION: The aim of this study was to compare canal transportation of two single-file systems, WaveOne Gold and Neoniti, using cone-beam computed tomography (CBCT). METHODOLOGY: A total of 40 mesiobuccal canals of maxillary first molars with curvatures of 15°-30° were chosen and randomly divided into two experimental groups (n = 20). In both groups, glide path was established using ProGlider. In group 1, canals were shaped with WaveOne Gold and in group 2 with Neoniti A1, respectively. According to manufacturer's instructions, canal preparation was made. Canals were scanned before and after instrumentation using CBCT scanner to evaluate root canal transportation at 3, 5, and 7 mm from the apex. Data were statistically analyzed, and significance level was set at P < 0.05. RESULTS: Mesiodistal and buccolingual transportation showed a statistically significant difference at 3 mm (P = 0.009) and 7 mm (P = 0.002), respectively, when instrumented with Neoniti than WaveOne Gold. CONCLUSION: WaveOne Gold single reciprocation file respected original canal anatomy better than Neoniti single continuous file.