Mandibular asymmetry in unilateral and bilateral posterior crossbite patients using cone-beam computed tomography

Abstract

Objective: To test the hypotheses that (1) there is no difference in mandibular asymmetry between the crossbite and normal side in a unilateral crossbite group (UCG) and between the right and left sides in a bilateral crossbite group (BCG) and a control group (CG); and (2) there is no significant difference in mandibular asymmetry among crossbite groups and control group. Materials and Methods: The cone-beam computed tomography scans of three groups were studied: (1) 15 patients (6 male, 9 female; mean age: 13.51 6 2.03 years) with unilateral posterior crossbite; (2) 15 patients (8 male, 7 female; mean age: 13.36 6 2.12 years) with bilateral posterior crossbite; and (3) 15 patients (8 male, 7 female; mean age: 13.46 6 1.53 years) as a control group. Fourteen parameters (eight linear, three surface, and three volumetric) were measured. Side comparisons were analyzed with paired samples t-test, and for the intergroup comparison, analysis of variance (ANOVA) and Tukey tests were used at the P , .05 level. Results: According to side comparisons, no statistically significant difference was found in the UCG. There were statistically significant differences in hemimandibular (P 5 .008) and ramal (P 5 .004) volumes for the BCG and in ramal height (P 5 .024) and body length (P 5 .021) for the CG. Intergroup comparisons revealed significant differences in hemimandibular (P 5 .002) and body volume (P , .001) for the normal side of the UCG and left sides of the other groups, and in angular unit length (P 5 .025) and condylar width (P 5 .007) for the crossbite side of the UCG and the right sides of the other groups. Conclusions: Contrary to UCG, CG and BCG were found to have side-specific asymmetry. Skeletal components of the mandible have significant asymmetry among the crossbite groups and the CG. (Angle Orthod. 2011;81:966-974.)

Mandibular vertical asymmetry in adult orthodontic patients with different vertical growth patterns: A cone beam computed tomography study

“…The threshold value could be set from the scan, the required structure could be separated from its surrounding structures, and the software allows us to visualize an area that was superimposed by other structures and to evaluate its actual dimensions. 10 The Houston and correlation analyses confirmed the high reliability of the variable values as previously reported for the CBCT images of the twoand three-dimensional measurements. 10,11,18,[26][27][28][29][30][31] Comparing right and left sides for the CH, RH, and CH + RH values in the high-, low-, and normal-angle groups showed only a slight difference of approximately 0.5 mm for CH in the low-angle group (P , .05), indicating an almost symmetrical posterior vertical height of the mandible in all studied groups.…”

“…24 Contemporary three-dimensional technology makes it feasible to achieve true (1:1 in size) images devoid of magnification. 10 Although radiation exposure could be an issue, CT is the gold standard for determining condylar asymmetries. 25 In the present study, CBCT images were used to assess condylar and ramal vertical asymmetry in adult patients having various vertical growth patterns since CBCT provides a relatively low radiation dose with low costs compared with CT.…”

“…5,6 Habets et al 7 described a method for evaluating mandibular vertical asymmetry by calculating the condylar and ramal heights to compare the right and left sides of the mandible. Several authors have used this method to assess mandibular asymmetry in patients with temporomandibular disorders, 8 unilateral and bilateral posterior crossbites, [9][10][11] various sagittal malocclusions, 12-14 unilateral 15 and bilateral molar extractions, 16 and cleft lip and palate. 17,18 Although mandibular vertical asymmetry has appeared frequently in the literature, a bibliographic search in Medline using PubMed and the key words ''condylar asymmetry,'' ''mandibular asymmetry,'' ''vertical growth pattern,'' and ''CBCT'' revealed that no published study has evaluated condylar and ramal vertical asymmetry using cone-beam computed tomography (CBCT) in patients with different vertical growth patterns.…”

Improvement of masticatory kinematic parameters after correction of unilateral posterior crossbite: Reasons for functional retention

“…1,6 They occur during chewing on the crossbite side only while, on the nonaffected side, the pattern maintains physiological features. 5 This results in compensatory asymmetric function, 1 worsening of unbalance of skeletal growth, neuromuscular structures, 7 and temporomandibular joint over time. 8,9 The literature shows that the dental correction of UPCs can be obtained with or without the correction of reverse chewing patterns 3,4 depending on therapy and appliance selection.…”

Perawatan Cross Bite Posterior Unilateral Menggunakan Alat Ortodontik Cekat Teknik Begg

“…Cross bite posterior unilateral disebabkan karena berbagai faktor diantaranya yaitu adanya persistensi atau prolong retensi gigi desidui, malposisi gigi ke arah lingual pada gigi-gigi maksila, kebiasaan buruk seperti bertopang dagu satu sisi, dan adanya pengaruh deviasi mandibular ketika menutup mulut. 4,5,6 Cross bite posterior bilateral ditandai dengan tonjol bukal gigi posterior maksila beroklusi di lingual tonjol bukal gigi posterior mandibula kedua sisi, disebabkan lengkung mandibula lebih lebar daripada lengkung maksila. 7 Teknik Begg merupakan salah satu teknik perawatan ortodontik dengan alat cekat yang dapat digunakan untuk merawat kasus maloklusi yang disertai malrelasi cross bite posterior unilateral.…”