Position of impacted mandibular third molar in different skeletal facial types: First radiographic evaluation in a group of Iranian patients.
OBJECTIVE
This study was performed to evaluate the position of impacted mandibular third molars in different skeletal facial types among a group of Iranian patients.


METHODS
A total of 400 mandibular third molars in 200 subjects with different types of facial growth were radiographically investigated for their positions according to their types of facial growth on the basis of the β angle. The subjects were divided into three groups (class I, II, and III) according to ANB angle, representing the anteroposterior relationship of the maxilla to the mandible. Meanwhile, the subjects were also divided into three groups (long, normal, and short face) according to the angle between the stella-nasion and mandibular plane (SNGoGn angle). ANOVA was used for statistical analysis.


RESULTS
The mean β angle showed no significant difference among class I, II, and III malocclusions (df=2, F=0.669, p=0.513). The same results were also found in short, normal, and long faces (df=1.842, F=2, p=0.160). The mesioangular position was the most frequent one in almost all of the facial growth patterns. Distoangular and horizontal positions of impaction were not found in the subjects with class III and normal faces. In the long facial growth pattern, the frequency of vertical and distoangular positions were not different.


CONCLUSIONS
In almost all of the skeletal facial types, the mesioangular impaction of the mandibular third molar was the most prevalent position, followed by the horizontal position. In addition, β angle showed no significant difference in different types of facial growth.
Department of Oral and Maxillofacial Radiology, Dental School, Hamadan University of Medical Sciences, Hamadan, Iran.
Abbas
A
Shokri
Department of Orthodontics, Dental School, Hamadan University of Medical Sciences, Hamadan, Iran.
Majid
M
Mahmoudzadeh
Department of Oral Medicine, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Maryam
M
Baharvand
Department of Oral Medicine, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Hamed
H
Mortazavi
Department of Epidemiology and Statistics, Medical School, Hamadan University of Medical Sciences, Hamadan, Iran.
Javad
J
Faradmal
Department of Oral and Maxillofacial Radiology, Dental School, Hamadan University of Medical Sciences, Hamadan, Iran.
Samira
S
Khajeh
Department of Oral and Maxillofacial Radiology, Dental School, Hamadan University of Medical Sciences, Hamadan, Iran.
Faezeh
F
Yousefi
Department of Oral and Maxillofacial Radiology, Dental School, Hamadan University of Medical Sciences, Hamadan, Iran.
Maruf
M
Noruzi-Gangachin
Malocclusion; Mandible; Molar, Third; Tooth, Impacted