Normative Upper Incisor Inclination Relative to the True Horizontal Plane (THP) on Cone-beam Computed Tomography (CBCT) Images in Korean Adults
Janghoon Ahn1 , Beulha Kim1 , SungBae Choi1 , Eunkyung Nam1 , Sukho Yoon1 , Minbong Park2 , Ami Kim3
1 Department of Orthodontics, Hallym University Kangnam Sacred Heart Hospital, Seoul,
2 Seoul Miso Dental Clinic, Seoul,
3 Seoul Top Dental Clinic, Ulsan, Korea
Purposes: The aim of this study was to identify normative values after measuring the upper incisor inclination following the reconstruction of true horizontal plane (THP) on cone-beam computed tomography (CBCT) images taken in the status of natural head position (NHP) in Korean adults with normal facial appearances.
Materials & Methods: Subjects were selected from patients who had visited the department of dentistry with a chief complaint of the 3rd molar extraction, those who underwent CBCT scanning for further evaluation of the proximity between the root of the mandibular 3rd molar and the inferior alveolar nerve on panoramic view. Facial appearances were evaluated by examiners, then CBCT images of total 110 subjects (52 men and 58 women) were finally obtained. Upper incisor inclinations were calculated relative to the THP and palatal plane (PP). Student's t-test was used to assess sexual differences in these measurements.
Results: The mean angular measurements of upper incisor were 117.97o (standard deviation [SD], 4.78o ) relative to THP, 118.35o (SD, 6.76o ) relative to PP in Korean males, and 116.26o (SD, 6.06o ), 120.33o (SD, 9.34o ) respectively in Korean females. There were no significant differences between Korean males and females (p<0.05).
Conclusion: The measurement of upper incisor inclination relative to THP using 3-dimensional CBCT analysis might be of great clinical significance in the discussion of desirable location of the anterior teeth in Korean patients who are in need of orthodontic therapies for the aesthetic improvement of facial appearances.
Key words: Upper incisor inclination, True horizontal plane, Natural head position, Cone-beam computed tomography
Korean J Lingual Orthod 2016;5(1):10-17
Comments