Establishing H Angle Hard Tissue and H Angle Soft Tissue Norms in Skeletal Class I Malay Adult Females and the Correlation between the H Angles and Visual Perception of Laypersons.

Abstract

Objectives:  This study aimed to establish the cephalometric norms of H angle soft tissue and H angle hard tissue of Malaysian Malay adult females, and to evaluate the correlation between H angles and visual perception in skeletal Class I Malay adult females.

Materials and methods:  Eighty-five lateral cephalograms of skeletal Class I (mean ANB value = 3.15 ± 0.77) Malaysian Malay female patients aged 20 to 40 years (mean age = 28.6 ± 5.86 degrees) taken from October 2017 to December 2021 were measured for H angle soft tissue and H angle hard tissue. Twenty silhouettes were then converted from cephalometric films and were rated according to facial convexity/concavity by 20 laypersons, with re-evaluation after 2 weeks for intra- and interexaminer reliabilities.

Results:  The means of the H angle soft tissue and H angle hard tissue were 15.75 ± 4.16 degrees and 11.64 ± 4.71 degrees, respectively. The intraexaminer reliability test for visual perception ranged from -0.89 to 0.99 indicating poor to excellent reliability, whereas the interexaminer reliability test was 0.82 indicating good reliability. A highly statistically significant association between the H angle soft tissue and H angle hard tissue (r = 0.938; p < 0.01) was found. There was no correlation between H angles and visual perception.

Conclusion:  The cephalometric norms of H angle hard tissue and H angle soft tissue in the Malaysian Malay female population were established: 11.64 degrees (±4.71 degrees) and 15.75 degrees (±4.16 degrees), respectively. There was a strong correlation between H angle soft tissue and H angle hard tissue among skeletal Class I Malay adult females. There was no correlation between H angles and the visual perception of laypersons.