Morphology Analysis of Human Fourth Molars Using Computed Microtomography - Pilot Study

Analyze the morphological characteristics of fourth molars from non-syndromic patients using computed microtomography (microCT). Five human fourth molars (case group) and other three third molars (control group) were obtain from Biobank of UFPR Dentistry School. The teeth were submitted to macroscopic and microCT analysis. Sample characteristics: 60% of the teeth from the lower arch, mainly from the right lower arch (40%). The results showed that eighty percent of the teeth were impacted and all of them presented normal morphology. The microCT revealed that one of the fourth molars had hypercementosis. Concerning the root canal anatomy, all of the fourth molars studied had just one principal root canal. Four teeth had one collateral canal that ended at the lateral face of the root. The volume average of root canal, dentine and enamel were respectively 9.27 mm3, 122.64 mm3 and 74.71 mm3. The averages between these variables in third molars were 46.98 mm3, 473.25 mm3 and 198.34 mm3, respectively. Proportionally, the volume of the fourth molars was five times less than the third molars, but the dentine and enamel volume were, respectively, 3.8 and 2.7 times less than third molars. The fourth molar teeth usually showed only one principal root canal and it can be associated with other alterations, such as hypercementosis. Although the fourth molars were smaller, the proportion of enamel volume is bigger than third molar in comparison.