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

Int Endod J. 2023 May;56(5):637-646. doi: 10.1111/iej.13891. Epub 2023 Feb 2.

Abstract

Aim: The 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).

Methodology: A 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).

Results: Dentine 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 ( CONCLUSION: Minimum dentine thickness values at the danger zone of distobuccal and palatal canals change according to the fusion type in fused maxillary second molars.

Keywords: danger zone; dentine thickness; endodontics; fusion; microtomography; root canal anatomy.

MeSH terms

  • Dental Pulp Cavity / diagnostic imaging
  • Dentin / diagnostic imaging
  • Maxilla / diagnostic imaging
  • Molar* / diagnostic imaging
  • Tooth Root*
  • X-Ray Microtomography