Factors affecting root curvature of mandibular first molar.
- Author:
Hang Moon CHOI
1
;
Won Jin YI
;
Min Suk HEO
;
Sam Sun LEE
;
Jung Hwa KIM
;
Soon Chul CHOI
;
Tae Won PARK
Author Information
1. Department of Oral and Maxillofacial Radiology, College of Dentistry, Kangnung National University. imagchoi@kangnung.ac.kr
- Publication Type:Original Article
- Keywords:
Root Curvature;
Ramus-Occlusal Plane Angle;
Long Axis, Tooth;
Digital Subtraction Radiography
- MeSH:
Axis, Cervical Vertebra;
Dental Occlusion;
Molar*;
Mouth;
Radiography;
Tooth;
Tooth, Deciduous
- From:Korean Journal of Oral and Maxillofacial Radiology
2006;36(1):55-62
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
PURPOSE: To find the cause of root curvature by use of panoramic and lateral cephalometric radiograph. MATERIALS AND METHODS: Twenty six 1st graders whose mandibular 1st molars just emerged into the mouth were selected. Panoramic and lateral cephalometric radiograph were taken at grade 1 and 6, longitudinally. In cephalometric radio graph, mandibular plane angle, ramus-occlusal plane angle, gonial angle, and gonion-gnathion distance (Go-Gn distance) were measured. In panoramic radio graph, elongated root length and root angle were measured by means of digital subtraction radiography. Occlusal plane-tooth axis angle was measured, too. Pearson correlations were used to evaluate the relationships between root curvature and elongated length and longitudinal variations of all variables. Multiple regression equation using related variables was computed. RESULTS: The Pearson correlation coefficient between curved angle and longitudinal variations of occlusal planetooth axis angle and ramus-occlusal plane angle was 0.350 and 0.401, respectively (p<0.05). There was no significant correlation between elongated root length and longitudinal variations of all variables. The resulting regression equation was Y=10.209+0.208X1+0.745X2 (Y: root angle, X1: variation of occlusal plane-tooth axis angle, X2: variation of ramus-occlusal plane angle). CONCLUSION: It was suspected that the reasons of root curvature were change of tooth axis caused by contact with 2nd deciduous tooth and amount of mesial and superior movement related to change of occlusal plane.
