Root canal morphology of hypomineralised first permanent molars using micro-CT.

AIM: To investigate the root canal morphology of hypomineralised first permanent molars (FPMs) using micro-CT (µCT). METHODOLOGY: Twenty-four hypomineralised FPMs and five clinically sound FPMs were scanned using µCT and assessed using the following parameters: (i) root canal configuration, (ii) connecting canal frequency, (iii) enamel, dentin, and pulp volumes, (iv) cusp tip to pulp horn distance, root canal length, root canal width, and dentin thickness, and (v) the influence of the root canal system landmarks on access cavity outline forms and canal curvature. A two-way repeated-measures analysis of variance was employed with the statistical significance set at p < 0.05. RESULTS: The frequency of accessory and connecting canals was higher in hypomineralised FPMs. Mesio-buccal cusp horn was found to be the closest to its corresponding cusp tip in both groups. There was no significant difference between the root lengths, dentine widths, and pulp space measurements of hypomineralised FPMs compared to clinically sound FPMs. The best angulation to access FPMs was straight-line radicular, along the pulp horn. CONCLUSIONS: This study illustrates some variations in the root canal morphology in hypomineralised FPMs compared to clinically sound FPMs. Future studies should focus on assessing these parameters in larger samples.

Tooth mineral density of different types of hypomineralised molars: a micro-CT analysis.

AIM: This study sought to evaluate the tooth mineral density (TMD) for the different lesion types in hypomineralised first permanent molars (FPMs) and compare them to unaffected enamel in clinically sound FPMs. DESIGN: Eighteen FPMs with varying degrees of hypomineralised enamel were grouped into brown, yellow/creamy and white lesion types. Micro-CT was used to determine the TMD for each lesion type, and for unaffected enamel at different locations in the outer, middle, and inner-third of the enamel. RESULTS: The average TMD for brown, yellow/creamy, white and unaffected enamel was 1.79, 2.21, 2.43 and 2.46 g/cm3, respectively. Brown and yellow/creamy lesions exhibited a statistically significant difference when compared to white lesions and unaffected enamel. However, no statistical difference was evident in TMD between white lesions and unaffected enamel. The TMD increased from the outer-third to inner-third for brown and yellow/creamy lesions (p < 0.05), while in white lesions and unaffected enamel, the TMD decreased from the outer-third to inner-third (p < 0.05). CONCLUSION: TMD was lowest for brown lesions followed by yellow/creamy lesions while the TMD for white lesions was similar to unaffected enamel.