Dentine thickness in maxillary fused molars depends on the fusion type: An ex vivo micro-computed tomography study

AimThe present study aimed to determine and compare the dentine thickness around the root canals of maxillary molars with fusion using micro-computed tomography (micro-CT). MethodologyA total of 120 fused maxillary molars having more than a single canal with distinct canal orifices near the cementoenamel junction were selected from a pool of extracted maxillary molars, which were scanned on a micro-CT device (SkyScan 1172, Bruker-microCT). The minimum dentine thickness around the root canals in furcal direction was measured using CTAn software (v.1.18.8 Bruker-microCT) at each millimetre. The specimens were grouped according to their fusion type, and dentine thickness around the canals was compared. The data were statistically analysed using anova and post hoc Tukey-Kramer tests following an assessment of the normality of their distribution with the Kolmogorov-Smirnov test (p < .05). ResultsDentine thickness showed a statistically significant decrease at 2 mm apical to the orifice level irrespective of fusion type. The minimum dentine thickness values were detected around the second mesiobuccal canal as 0.30 mm at 6 mm below orifice. Dentine thickness around the mesiobuccal canal was significantly greater in fusion type 1 than those of types 2 and 3 (p < .05), while those of distobuccal and palatal canals were significantly thinner in type 3 fusion compared with type 1 or 6 (pDentine thickness showed a statistically significant decrease at 2 mm apical to the orifice level irrespective of fusion type. The minimum dentine thickness values were detected around the second mesiobuccal canal as 0.30 mm at 6 mm below orifice. Dentine thickness around the mesiobuccal canal was significantly greater in fusion type 1 than those of types 2 and 3 ( ConclusionMinimum dentine thickness values at the danger zone of distobuccal and palatal canals change according to the fusion type in fused maxillary second molars.

Automated summary

This study used micro-CT to determine and compare the dentine thickness around root canals in fused maxillary molars. Results showed that the dentine thickness significantly decreased 2 mm apical to the orifice level regardless of fusion type. The minimum dentine thickness was found around the second mesiobuccal canal. The fusion type influenced the dentine thickness, with type 1 fusion having greater thickness around the mesiobuccal canal compared to types 2 and 3, while type 3 fusion had thinner dentine around the distobuccal and palatal canals.