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. 2022 Jul 17;22(1):292.
doi: 10.1186/s12903-022-02319-7.

Evaluation of factors related to morphological masseter muscle changes after preoperative orthodontic treatment in female patients with skeletal class III dentofacial deformities

Rei Jokaji  1 , Kazuhiro Ooi  2 , Tetsutaro Yahata  3 , Yusuke Nakade  4 , Shuichi Kawashiri  1
Affiliations

Evaluation of factors related to morphological masseter muscle changes after preoperative orthodontic treatment in female patients with skeletal class III dentofacial deformities

Rei Jokaji et al. BMC Oral Health. .

Abstract

Background: The purpose of the current study was to investigate factors related to morphological changes in the masseter muscle after preoperative orthodontic treatment in patients with skeletal class III dentofacial deformities for analysis of muscle changes and malocclusions.

Methods: Twenty female patients with dentofacial deformities were included in the study. Computed tomography was performed before and after preoperative orthodontic treatment, and the lengths, widths, and cross-sectional areas of the masseter muscles were measured. Changes in these parameters were evaluated, and factors related to changes in masseter muscle area after preoperative orthodontic treatment were analyzed.

Results: The lengths, widths, and areas of masseter muscles were significantly smaller after preoperative orthodontic treatment. Smaller masseter muscle area was significantly associated with changes in overbite and pretreatment values of SNA angle.

Conclusions: Atrophy of the masseter muscle during preoperative orthodontic treatment was greater in patients with increased open bite due to improved dental compensation in patients with skeletal class III dentofacial deformities with maxillary retraction.

Keywords: Morphological changes of masseter muscle; Preoperative surgical orthodontic treatment; Skeletal class III dentofacial deformities.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig.1
Fig.1
Masseter muscle cross-sec < onal area was measured from 5 mm above the mandibular foramen parallel to the Frankfurt plane using CT images
Fig. 2
Fig. 2
Cephalometric measurements. A Anteroposterior cephalometric measurements. 1;DFFM at Menton (mm), 2;U1-L1 deviation (mm). B Lateral cephalometric measurements. 3;overjet (mm), 4;overbite (mm), 5;SNA angle (°), 6;SNB angle (°), 7;ANB angle (°), 8;GZN angle (°), 9;SN-MP angle (°). Cephalometric landmarks: menton (Me), midpoint of the upper incisor edge (U1), midpoint of the lower incisor edge (L1), sella (S), nasion(N), point A (A), point B (B), gonion (Go), arCculare (Ar). FM: facial midline, DFFM: DeviaCon from the facial midline
Fig. 3
Fig. 3
Comparison of masseter muscle length, width and area between before and after preoperative orthodonthic treatment
Fig. 4
Fig. 4
Figure shows a greater reduction of with and area compared to length
Fig. 5
Fig. 5
RelaFons between changes of cross secFonal masseter muscle area and changes of overbite and SNA angle
See this image and copyright information in PMC

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