Different mandibular first molar shapes according to groove and cusp configuration in relation to suggested bracket position.
The aim of this study was to explore the shape differences in the mandibular first molars through orthographic measurements using three-dimensional (3D) virtual models, and study the possibility of new morphologic categories that require more than subjective visual inspection. A total of 164 mandibular first molars with five cusps were selected for classification. Using 3D laser scanning and reconstruction software, virtual casts were constructed. After several linear and angular measurements on the virtual occlusal plane, the teeth were clustered using the partitioning around medoids methods-an unsupervised classification. The cluster analysis presented two clusters that showed statistically significant differences in the measurements over the cusp locations and groove configurations. However, gender differences were not shown in the angular groove and cusp configurations. Two clusters were found in the population of the present study, and this result suggested the existence of a diverse morphologic trait in the mandibular molar even in the same origin and could be considered in positioning orthodontic brackets that have built-in prescriptions.
* Dental Research Institute and School of Dentistry, Seoul National University, Departments of.
Doo Eun
DE
Park
Hong-Kyun
HK
Kim
Young Seol
YS
Lim
Michiko
M
Nakatsuka
Ho Beom
HB
Kwon
Seong Ho
SH
Han
Young-Seok
YS
Park
D002648:Child; D003198:Computer Simulation; D003766:Dental Occlusion; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008334:Mandible / Q000033:anatomy & histology*; D003765:Models, Dental; D008963:Molar / Q000033:anatomy & histology*; D016382:Orthodontic Appliance Design / Q000379:methods*; D016910:Orthodontic Brackets; D056910:Republic of Korea; D012737:Sex Factors; D012984:Software