Korean J Orthod.  2016 May;46(3):163-170. 10.4041/kjod.2016.46.3.163.

Assessment of anterior-posterior jaw relationships in Korean adults using the nasion true vertical plane in cone-beam computed tomography images

• Park Y
• Cho Y
• Mah J
• Ahn J

• KMID: 2164260
• DOI: http://doi.org/10.4041/kjod.2016.46.3.163

Abstract

OBJECTIVE
The aims of this study were to investigate a simple method for assessing anterior-posterior jaw relationships via cone-beam computed tomography (CBCT) images taken in the natural head position (NHP) relative to the nasion true vertical plane (NTVP), and measure normative data in Korean adults with normal profiles.
METHODS
Subjects were selected from patients presenting for third molar extraction and evaluated as having normal profiles by three examiners. The CBCT images of 80 subjects (39 males, 41 females) were taken in the NHP according to Solow and Tallgren's method. Linear measurements of the A-point, B-point, and Pog were calculated relative to the NTVP. Student's t-test was used to assess sexual differences in these measurements.
RESULTS
The mean linear measurements of the A-point, B-point, and Pog relative to the NTVP were 0.18 mm (standard deviation [SD], 4.77 mm), -4.00 mm (SD, 6.62 mm), and -2.49 mm (SD, 7.14 mm) respectively in Korean males, and 1.48 mm (SD, 4.21 mm), -4.07 mm (SD, 6.70 mm) and -2.91 mm (SD, 7.25 mm) in Korean females respectively. There were no statistically significant differences between Korean males and females (p < 0.05).
CONCLUSIONS
Three-dimensional CBCT analysis using the NTVP is a simple and reliable method for assessing anterior-posterior skeletal relationships.

Keyword

Natural head position; Nasion true vertical plane; Cone-beam computed tomography; Jaw relation

MeSH Terms

Adult*
Cone-Beam Computed Tomography*
Female
Head
Humans
Jaw*
Male
Methods
Molar, Third

Figure

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  Figure 1 Facial photographs (A) and cone-beam computed tomography images (B) were taken in a sitting position in accordance with Solow and Tallgren's18 method. Patients wore eyeglasses with two fluid levelers attached to the frame.

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  Figure 2 The angle between Ricketts' E-line and the true vertical line was measured in a facial profile photograph (A) and a cone-beam computed tomography image (B).

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  Figure 3 The process of constructing the nasion true vertical plane using In Vivo Dental software. A, A square box was visualized on the volume rendering screen with high brightness. B, Three points were digitized on the bottom surface parallel to the floor.

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  Figure 4 The true horizontal plane, midsagittal plane, and nasion true vertical plane were constructed.

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  Figure 5 After tracing all lines and digitizing the landmarks required, linear measurements of the A-point, B-point, and Pog relative to the nasion true vertical plane were calculated automatically via In Vivo Dental software (version 5.3; Anatomage Co., San Jose, CA, USA).

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