Korean J Orthod.  2021 Jan;51(1):23-31. 10.4041/kjod.2021.51.1.23.

Evaluation of mandibular buccal shelf characteristics in the Colombian population: A cone-beam computed tomography study

• Escobar-Correa N
• RamírezBustamante MA
• SánchezUribe LA
• Upegui-Zea JC
• Vergara-Villarreal P
• RamírezOssa DM

• KMID: 2510615
• DOI: http://doi.org/10.4041/kjod.2021.51.1.23

Abstract

Objective
To evaluate the mandibular buccal shelf (MBS) in terms of the angulation and bone depth and thickness according to sex, age, and sagittal and vertical skeletal patterns in a Colombian population using cone-beam computed tomography (CBCT). Accordingly, the optimal site for miniscrew insertion in this area was determined.
Methods
This descriptive, retrospective study included 64 hemi-arches of 34 patients. On CBCT images, the angulation, buccal bone depth (4 and 6 mm from the cementoenamel junction [CEJ] of MBS), and buccal bone thickness (6 and 11 mm from the CEJ of MBS) were measured at the mesial and distal roots of the mandibular first and second molars.
Results
There were no statistically significant differences in the angulation, depth, and thickness of MBS between male and female patients. The values for the bone around the distal root of the mandibular second molar were significantly greater than the other values. The osseous characteristics were significantly better in participants aged 16–24 years. Class III patients exhibited the best osseous characteristics, with the bone depth at 6 mm being significantly different from that in Class I and Class II patients. Although values tended to be greater in patients with low angles, the difference was not statistically significant.
Conclusions
MBS provides an optimal bone surface for miniscrew insertion, with better osseous characteristics at the distal root of the mandibular second molar, 4 mm from CEJ. Adolescent patients, Class III patients, and patients with a low angle exhibit the most favorable osseous characteristics in the MBS area.

Keyword

Miniscrew; Cone-beam computed tomography; Bone-implant contact; Anchorage

Figure

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  Figure 1 Cephalometric analysis according to the method of Kim.14,15

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  Figure 2 Reference orientation planes. A, Axial plane (purple line). B, Sagittal plane (blue line). C, Frontal/Coronal plane (orange line).

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  Figure 3 Analysis of the mandibular buccal shelf. A, Angulation: This is measured as the inner angle made by the axial axis of the molar and a tangent to the outermost surface of the buccal shelf. B, Apicocoronal depth: This is measured using two vertical lines drawn toward the outermost part of the cortex, from two horizontal reference lines from cementoenamel junction (CEJ), one at 4 mm and the other at 6 mm parallel to the Y axis. C, Thickness: This is measured using two horizontal lines drawn toward the outermost part of the cortex, from two vertical reference lines from CEJ, one at 6 mm and the other at 11 mm parallel to the Z axis.

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  Figure 4 Representative images showing analysis of the mandibular buccal shelf on cone-beam computed tomography images. A, Angulation measurement. B, Apicocoronal depth and thickness measurements. a: Depth measurements. b: Thickness measurements. *References lines for depth measurement at 4 and 6 mm from the cementoenamel junction (CEJ). †Reference lines for thickness measurement at 6 and 11 mm from CEJ.

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