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. 2015 Jan-Jun;6(1):125-30.
doi: 10.4103/0976-9668.149109.

Reliability of Beta angle in assessing true anteroposterior apical base discrepancy in different growth patterns

Shobha Sundareswaran  1 , Vinay Kumar  1
Affiliations

Reliability of Beta angle in assessing true anteroposterior apical base discrepancy in different growth patterns

Shobha Sundareswaran et al. J Nat Sci Biol Med. 2015 Jan-Jun.

Abstract

Introduction: Beta angle as a skeletal anteroposterior dysplasia indicator is known to be useful in evaluating normodivergent growth patterns. Hence, we compared and verified the accuracy of Beta angle in predicting sagittal jaw discrepancy among subjects with hyperdivergent, hypodivergent and normodivergent growth patterns.

Materials and methods: Lateral cephalometric radiographs of 179 patients belonging to skeletal Classes I, II, and III were further divided into normodivergent, hyperdivergent, and hypodivergent groups based on their vertical growth patterns. Sagittal dysplasia indicators - angle ANB, Wits appraisal, and Beta angle values were measured and tabulated. The perpendicular point of intersection on line CB (Condylion-Point B) in Beta angle was designated as 'X' and linear dimension XB was evaluated.

Results: Statistically significant increase was observed in the mean values of Beta angle and XB distance in the vertical growth pattern groups of both skeletal Class I and Class II patients thus pushing them toward Class III and Class I, respectively.

Conclusions: Beta angle is a reliable indicator of sagittal dysplasia in normal and horizontal patterns of growth. However, vertical growth patterns significantly increased Beta angle values, thus affecting their reliability as a sagittal discrepancy assessment tool. Hence, Beta angle may not be a valid tool for assessment of sagittal jaw discrepancy in patients exhibiting vertical growth patterns with skeletal Class I and Class II malocclusions. Nevertheless, Class III malocclusions having the highest Beta angle values were unaffected.

Keywords: Beta angle; sagittal dysplasia; vertical growers.

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Conflict of interest statement

Conflict of Interest: None declared.

Figures

Figure 1
Figure 1
Cephalometric parameters analyzed in study – Beta angle (XAB) and XB distance
Figure 2
Figure 2
Receiver operating characteristics curve for XB distance to discriminate skeletal Class II group from other groups
Figure 3
Figure 3
Receiver operating characteristic curve for XB distance to discriminate skeletal Class III from other groups
Figure 4
Figure 4
Right angled triangle AXB with beta angle
See this image and copyright information in PMC

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