The 'Wits' appraisal of a sample of the South Wales population

Comparison of Wits appraisal among different ethnic groups

Objectives:

The Wits values for various ethnic groups are different and the applicability of the norms described in these analyses to different populations is difficult. The objectives of this study were to establish the normal values of Wits appraisal in a sample from the western region of Saudi Arabia and to evaluate the existence of gender dimorphism. Also, to compare the results with previously published Wits values.

Materials and Methods:

A total of 66 lateral cephalometric digital radiographs of Saudi patients from the western region (25 males and 41 females, mean age 19.32±8.16 years and 20.88±8.77 years, respectively). All subjects had angle class-I occlusion, well-balanced faces, all premolars had erupted and in occlusion, and no history of orthodontic treatment. Tracing was performed using the VistadentOC^® software.

Results:

Wits mean values were greater in males (−0.73±2.48) than females (1.79±2.06), with significant gender difference (P<0.001). Comparisons with previously published showed that there is a significant differences between ethnic groups, especially in females’ data.

Conclusion:

Wits appraisal appears to be gender-specific and ethnicity-specific for female values.

Influence of occlusal plane inclination on ANB and Wits assessments of anteroposterior jaw relationships

INTRODUCTION

Although assessments of anteroposterior relationships are vital for orthodontic treatment planning, they cannot be precisely achieved by current cephalometric and noncephalometric resources. ANB angle and the Wits appraisal are the most popular cephalometric measurements applied in clinical orthodontics, although they have drawbacks. Facial vertical features, especially the occlusal plane angle, play an important role in their assessment, contributing to their unreliability.

METHODS

To further understand the influence of occlusal plane inclination, ANB angle and the Wits appraisal were analyzed in cephalo-lateral radiographs of 122 finished orthodontic patients in 2 groups: high occlusal plane angle and low occlusal plane angle.

RESULTS

There was a tendency for inconsistency between ANB and Wits assessments in the high occlusal plane angle group and a tendency for consistency in the low occlusal plane angle group. Cranial base influences on ANB and Wits assessments were investigated by subdividing the groups. Any of the considered cranial base factors was decisive for lack or presence of consistency between ANB and Wits assessments.

CONCLUSIONS

The clinician should beware of possible misinterpretations when using ANB and Wits to assess the anteroposterior relationship of the jaws, especially in high occlusal plane angle patients.

Comparison between cephalometric classification methods for sagittal jaw relationships

The present study evaluated how 2 widely used cephalometric sagittal analyses, ANB angle and WITS appraisal, classify skeletal classes I, II, and III in a random selection of 497 Finnish boys aged 4-20 years. This distribution was also compared with the visual inspection of cephalometric structures judged by 2 university instructors in orthodontics. The results showed remarkable differences and even sparked controversy concerning classification of the sagittal jaw relationships. The ANB angle and the WITS appraisal emphasized the role of class II based on a failure to distinguish the proportion of class I. The low-angle influence skewed the distribution of the ANB pattern in the class III direction, and the WITS pattern, conversely, towards class II. High- or low-angle influence had only minor effects on the visual inspection of cephalometric structures. This cross-sectional study showed an age-related decreasing mean value for the ANB angle and increasing mean value for the WITS appraisal, thus explaining the remarkable difference in the distribution of sagittal classes. However, the findings of age-related changes makes the use of the fixed norms questionable. For extreme or controversial cephalometric interpretations, visual inspection provides an essential aid in diagnosis and skeletal classification.

The relationship and reproducibility of angle ANB and the Wits appraisal

An analysis is presented of the errors and variations in the Wits analysis and the angle ANB, using computer simulation. The method is applicable to any index where the identification errors have been established for the points and planes used in its derivation. A standard deviation may be determined for the index produced and the statistical distribution of values for any number of observations.

A comparison of ANB, WITS, AF-BF, and APDI measurements

In the present study, the relationships among ANB, Wits, AF-BF, and APDI measurements used in the assessment of the anteroposterior jaw disorders were examined on the cephalometric radiographs of 63 male and 82 female subjects, and high correlations were found among them. Furthermore, relationships were explored between these parameters and some measurements that were thought to have influenced them. The results of the geometric studies could not be proved on the basis of statistical evaluation.