Influence of obturating techniques on root dentin crack propagation: A micro-computed tomography assessment.

AIM: The aim is to assess and compare the microcrack formation in radicular dentin after obturating the root canals with cold lateral condensation (CLC), warm vertical condensation (WVC), and injectable gutta-percha (IGP) techniques using micro-computed tomography (CT). MATERIALS AND METHODS: Human extracted mandibular premolar teeth (n = 60) were haphazardly assigned based on the obturation technique into three experimental groups (n = 20 each). Root canals are cleaned and shaped with M Two rotary files and 3% sodium hypochlorite irrigant. Cross-sectional images were taken with Micro-CT to record the baseline defects present on root samples. After root canal obturation either with CLC or WVC or injectable obturation techniques, micro-CT images were captured again to analyze the increase in the number and type of dentinal defects. Statistical analysis of data was performed using the Mann-Whitney U test and the Mcnemar test at 5% significance level. RESULTS: An increase in the number of radicular micro-cracks was identified in samples obturated with lateral condensation technique (1.66%). No change in the percentage of micro-cracks was recorded after obturation with warm vertical or injectable guttapercha (IGP) techniques (P > 0.05). The three obturation techniques were not statistically different in the occurrence of micro-cracks after obturation. CONCLUSION: The three obturating techniques tested showed no significant increase in radicular dentin defects' occurrence or propagation.

Influence of obturation technique on penetration depth and adaptation of a bioceramic root canal sealer.

AIM: Evaluation of the impact of three different obturation techniques on the penetration depth and adaptation of a bioceramic root canal sealer(BioRoot RCS) to root dentin using scanning electron microscope and confocal laser scanning microscope. MATERIALS AND METHODS: Recently extracted ninety mandibular premolar teeth of similar dimensions (±0.2 mm) with single canals and straight roots were segregated into three experimental groups (n = 30 each) based on the method of obturation used, i.e., lateral compaction technique, warm vertical compaction technique, and injectable thermoplasticized technique. After obturation, half of the root samples (n = 15) in each group were sectioned horizontally by hard tissue microtome at 3, 6, and 9 mm, respectively, from root apex for measuring sealer penetration depth with a confocal laser scanning microscope. Longitudinal sections of the samples (n = 15) were used for measuring the adaptation of sealers to radicular dentin using a scanning electron microscope. STATISTICAL ANALYSIS: Intergroup comparison of sealer penetration depth and adaptation to root dentin was analyzed using one-way ANOVA, and pairwise comparisons were made using Tukey's post hoc test. RESULTS: Warm vertical condensation technique showed deeper root dentin penetration of the sealer. Better adaptation of the sealer to apical root dentin with minimal voids (P ≤ 0.05) was achieved with warm vertical condensation in comparison to the injectable gutta-percha method and lateral condensation obturating techniques. CONCLUSION: At all three root levels (coronal, middle, and apical), warm vertical condensation technique exhibited more sealer penetration with minimum gaps, whereas lateral condensation technique exhibited more gaps and less sealer penetration.

Efficacy of hydroxyapatite and silica nanoparticles on erosive lesions remineralization.

AIM: The aim is to assess and compare the mineral gain and penetration depth of hydroxyapatite and silica nanoparticle infiltrates into artificially created erosive lesions of enamel and dentin. MATERIALS AND METHODS: Sixty extracted human molars were sectioned to obtain enamel and dentin samples (n = 60 each). They were demineralized using citric and formic acid, respectively, to create erosive lesions on enamel and dentin surfaces. Samples were assigned into nanohydroxyapatite (nHA) or nanosilica groups (n = 30 each) according to the infiltrant used. Half of the enamel and dentin samples in each group (n = 15) were analyzed after erosive attack for mineral loss, after infiltrant application for mineral gain, using energy-dispersive X-ray spectroscopy. In another half of the enamel and dentin samples (n = 15), the penetration depth of the nanoinfiltrants was analyzed using confocal microscopy. STATISTICAL ANALYSIS: To compare the overall mineral gain between groups, a dependent t-test was applied. The intergroup comparisons were made using one-way ANOVA followed by Tukey post hoc test for pairwise comparisons for both penetration depth and mineral gain. The significance level was set to P ≤ 0.05. RESULTS: The mineral gain in enamel was not statistically different between nHA and nanosilica infiltrants (P = 0.9950). nHA infiltrated dentin showed significantly more mineral gain (P = 0.0001) than nanosilica infiltrant. The depth of penetration of the nHA in enamel was statistically greater than that of nanosilica, but in dentin, the difference was not significant. CONCLUSION: nHA infiltrant performed better in mineral gain, and penetrated deeper into the demineralized erosive lesions, compared to nanosilica infiltrant in both enamel and dentin. The highest mineral precipitation and deeper penetration into both demineralized enamel and dentin was observed with nHA infiltrant compared to (as against) nanosilica infiltrant.