Relationship between occlusal curvatures and mandibular deviation in orthodontic patients with temporomandibular disorders

Clinical research on the relationship between the curve of Wilson and temporomandibular joint disorders

OBJECTIVE

The aim of this study was to examine the relationship between the curve of Wilson (COW) and temporomandibular joint disorder (TMD).

METHODS

The study cohort comprised patients aged 19-55 with malocclusion treated at our institution from January to July 2021. They were divided into a malocclusion with TMD group (TMD group) and a malocclusion without TMD group (non-TMB group) based on the diagnostic criteria of TMD. The study outcome was the differences in COW, measured via cone beam computed tomography (CBCT), and statistical analysis was performed using one-way analysis of variance and t-test.

RESULTS

A total of 250 adult individuals were enrolled, including 162 females (age: 36.43 ± 11.00 years) and 88 males (age: 36.33 ± 9.88 years). Compared with the non-TMB group (n = 125), the TMD group (n = 125) had a significantly greater angle of COW (first molars: P = 0.002; second molars: P < 0.001), higher buccal inclination angle of molars in those with same side temporomandibular joint (TMJ) sounds than those with TMJ sounds (first molar: P = 0.000; second molar: P = 0.006) and greater the side with TMJ sounds (first molar: P < 0.001; second molar: P = 0.016). However, no difference was observed in the buccolingual axial inclination angle of molars between patients with and without TMJ sounds.

CONCLUSION

The study reported the differences in malocclusion patients with and without TMB, which could be used as a reference by dentists to improve the treatment outcomes of these patients.

Evaluation of the Relationship between Curve of Spee, WALA-FA Distance and Curve of Wilson in Normal Occlusion

Objective

To test the hypotheses that (i) there is a significant correlation between the curve of Spee (COS), basal arch (WALA ridge) to dental arch distance (WALA-FA distance) and curve of Wilson (CW) and that (ii) the deepening of the COS is affected by the CW and the WALA-FA distance.

Methods

Mandibular models of 50 patients aged between 20 and 35 years were scanned with TRIOS. The xyz coordinate system was determined, and a reference occlusal plane was generated. The depth of the COS, the CW, and WALA-FA distance were measured using an engineering software.

Results

The greatest difference in the measurement of the depth of the COS between the right and left was found to be 0.41±0.50 mm in the first molar teeth. On the basis of the results of Pearson correlation analysis, there was no strong correlation between the depth of the COS, the CW, and the WALA-FA distance.

Conclusion

It was shown that there was no strong correlation between the depth of COS, CW, and WALA-FA distance. The CW and WALA-FA distance could not be effective in the deepening of the COS.

Correlations between mandibular asymmetries and temporomandibular disorders (TMD)

INTRODUCTION

Mandibular asymmetries are the fulcrum of many debates among modern orthodontists and maxillofacial surgeons. The interest is even greater when facial asymmetries are correlated to the development of TMJ symptoms and temporomandibular disorders (TMD).

OBJECTIVE

The aim of this study is to investigate how mandibular asymmetries constitute etiological or predisposing factors for the development of temporomandibular disorders (TMD). We considered patients with mandibular asymmetries associated with TMD. Using orthodontic or surgical-orthodontic treatment, patients experienced correction of their TMJ symptoms. Thus, mandibular asymmetries represent a major risk factor for the development of TMD.

MATERIAL AND METHODS

We studied a sample of 16 subjects aged between 14 and 36-years-old (11 females and 5 males) with mandibular asymmetries (81% structural asymmetry, 19% functional asymmetry). These subjects presented skeletal and dental malocclusions combined with several temporomandibular disorders, mostly due to muscle tension. In 100% of cases, patients received orthodontic treatment. We compared pre- and post-treatment postero-anterior (PA) cephalometric analyses in order to evaluate asymmetry resolution.

RESULTS

Comparison of measurements from pre- and post-therapy PA cephalograms showed resolution of mandibular asymmetries after treatment. The treatment resolved mandibular asymmetries and completely eliminated temporomandibular symptoms.

CONCLUSIONS

Orthodontic treatment of patients presenting mandibular asymmetry enables correction of all TMJ symptoms and TMD. Mandibular symmetries can therefore be considered to constitute etiological or predisposing factors for the development of TMD.

The role of occlusal curvatures and maxillary arch dimensions in patients with signs and symptoms of temporomandibular disorders

OBJECTIVE

To identify differences in occlusal curvatures and maxillary arch dimensions between subjects with signs and symptoms of temporomandibular disorders TMDs and asymptomatic subjects.

MATERIALS AND METHODS

One hundred subjects 78 female and 22 male who consented to participate in this research were examined for signs and symptoms of TMDs according to the guidelines of the Research Diagnostic Criteria for Temporomandibular Disorders RDCTMD. In addition, occlusal measurements were performed for all subjects on plaster models. All statistical analyses were performed with SPSS version 19.

RESULTS

Significant associations were revealed between the depth of the curve of Spee COS and temporomandibular joint TMJ sounds. Furthermore, maxillary arch width was negatively correlated to the steepness of the curve of Wilson. No differences were found between subjects with and without a history of orthodontic treatment.

CONCLUSIONS

Subjects with TMJ sounds tend to have a flatter COS compared to subjects without TMJ sounds.

Skeletal pattern in subjects with temporomandibular joint disorders

INTRODUCTION

To establish the skeletal pattern in subjects with malocclusions and temporomandibular disorders (TMD); to assess the relationship between craniofacial skeletal structures and TMD in subjects with malocclusions.

MATERIAL AND METHODS

Sixty-four subjects with malocclusions, over 18 years of age, were included in the study. Temporomandibular disorders were clinically assessed according to the Helkimo Anamnestic Index. Subjects underwent a lateral cephalogram. Subjects were grouped according to the sagittal skeletal pattern (ANB angle) into class I, II and III. Parametric Student tests with equal or unequal variations were used (variations were previously tested with Levene test).

RESULTS

Twenty-four patients with TMD (experimental sample); 40 patients without TMD (control group); interincisal angle was higher in class I and II (p < 0.05) experimental subjects; overjet was larger in experimental subjects; midline shift and Wits appraisal were broader in the experimental group in all three classes. In class III subjects, the SNB angle was higher in the experimental group (p = 0.01). Joint noises followed by reduced mandible mobility, muscular pain and temporomandibular joint (TMJ) pain were the most frequent symptoms in subjects with TMD and malocclusions.

CONCLUSIONS

Temporomandibular joint status is an important factor to consider when planning orthodontic treatment in patients with severe malocclusions; midline shift, large overjet and deep overbite have been associated with signs and symptoms of TMD.

Posteroanterior cephalometric changes in subjects with temporomandibular joint disorders

OBJECTIVES

The aim of the study was to establish the changes in posteroanterior cephalometric variables in subjects with temporomandibular joint disorders (TMDs).

METHODS

Posteroanterior cephalograms of 61 subjects (age range 16-36.6 years, standard deviation 4.88 years) were used to determine cephalometric differences. Subjects were classified according to the Research Diagnostic Criteria for Temporomandibular Joint Disorders into three groups: unilateral TMD, bilateral TMD and no TMD. 14 linear and angular measurements were assessed on the posteroanterior cephalogram. For assessing facial asymmetry, the asymmetry index for bilateral measurements was calculated between the right and the left side. In cases with unilateral TMD, the asymmetry index was calculated using the difference between the unaffected and affected side. The differences among multiple groups were analysed using the one-way analysis of variance test and Scheffé post hoc test.

RESULTS

47 subjects were females (77%) and 14 were males (23%). 19 subjects had unilateral TMDs and 16 subjects had bilateral TMDs. The asymmetry index of the distance from the horizontal plane to the antegonion was higher in subjects with unilateral TMD than in patients with bilateral or no TMD (p < 0.05). Also, the asymmetry index of the distances from the vertical plane to the condyle (p = 0.05), gonion (Go) (p = 0.0004), antegonion (p = 0.002) and chin (Ch) (p = 0.02) was higher in subjects with unilateral TMDs. The asymmetry index of the O point-Go-Go' and O point-Ch-Ch' angles differed significantly in subjects with unilateral TMDs (p < 0.05).

CONCLUSIONS

Unilateral TMDs are associated with changes in posteroanterior cephalometric measurements. The assessment of posteroanterior cephalometric variables could be used as a key factor for evaluating the presence of TMDs.

Differential diagnosis of the idiopathic laterally deviated mandible

SUMMARY

Among patients who present for an orthognathic evaluation, a common finding is the presence of a laterally deviated mandible. At times, there is a cause to which the lower face asymmetry can be attributed, such as personal history of trauma to the face, presence of congenital disease known to affect the mandible, or other developmental abnormalities. More commonly, however, the patient is underdiagnosed and the cause of the idiopathic, laterally deviated mandible may be perplexing. The authors review the common causes of lateral deviation of the mandible and discuss how the growth of the mandible is affected and how the correct diagnosis may be ascertained. Among the common diagnoses, there are two major categories of mandibular asymmetry: (1) altered cranial base (e.g., muscular torticollis, unilateral craniosynostosis, and deformational plagiocephaly) and (2) condylar abnormality (e.g., condylar fractures, condylar hyperplasia, juvenile condylar arthritis, and hemifacial microsomia). Proper diagnosis and subsequent treatment of the underlying abnormality of the deviated mandible ensure the patient of the appropriate orthognathic reconstruction and decrease the likelihood of skeletal relapse after surgery.