Program including abstracts as pdf available here

OP 63
Title
CORRELATION OF MANDIbuLAR IMPACTED THIRD MOLAR AND MORPHOLOGy; CbCT STuDy
Authors
M.A. MOMIN 1,2 , K. MATSuMOTO 2 , K. EJIMA 2 , R. ASAuMI 1 , T. KAWAI 1 , y. ARAI 2 , K. HONDA 2 ,
T. yOSuE 1
Affiliations
1 Nippon Dental University, Tokyo, JAPAN, 2 Nihon University, Dept. of Oral and Maxillofacial
Radiology, Tokyo, JAPAN
Body
Objective: To determine the width and morphology of the mandible in the impacted third
molar region, and to identify the location of the mandibular canal prior to planning impacted
third molar operations.
Methods: Cone beam CT data of 90 mandibular third molars from 87 Japanese patients
(34 males, 53 females; age range 10-69 years) were analyzed in this study.
Measurement procedure: The width of the lingual cortical bone and apex-canal were measured
from certain cross-sectional images, in which the cortical bone was thinnest at the buccal or
lingual side in 3rd molar region was identified by three observers’ agreement and this crosssectional
image was used for measuring 3 variables: the space, apex-canal, and the cortical
bone width. The impacted molars (type A-C) and morphological shapes (type D-F) of mandibles
were classified using the cross-sectional images. A P value < 0.05 was considered to be statistically
significant.
Results: The means of the space, apex-canal and lingual cortical thickness were 0.31, 1.98, and
0.68 mm, respectively. Impacted third molar teeth (types A-C) were observed at the following
frequencies: type A, (angular) 37%; type B (horizontal), 42%; type C (vertical), 21%. The
morphology of the mandible at the third molar region (types D-F) was observed as: type D
(round), 49%; type E (lingual extended), 18%; and type F (lingual concave), 32%.
Conclusions: The width and morphology of the mandible with impacted teeth and the location
of the mandibular canal at the third molar region could be clearly determined using crosssectional
CBCT images.
Keywords
Third molar CBCT analysis
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