High Angle Cases in Different Types of Skeletal Pattern Among Malay Orthodontic Patients

High angle case is a type of malocclusion where the value of maxillo-mandibular plane angle (MMPA) exceed normal value and orthodontist often faces problem in managing patient with this type of case. This retrospective study was conducted to determine the prevalence and dentoalveolar features of high angle cases in Malay orthodontic patients treated in USIM specialist clinic. The sample comprised of 264 lateral cephalograms that were traced manually. The following values were assessed: ANB angle, MMPA, interincisal angle (IIA), upper molar angulation (UMA), lower molar angulation (LMA) based on 11 landmarks. Vertical skeletal pattern, anteroposterior skeletal pattern and dentoalveolar features based on interincisal angle and molar angulation were calculated. All data were analysed using descriptive statistic and chi square test. The prevalence of high angle cases were the highest in class II skeletal pattern. There was significant association between anteroposterior and vertical skeletal pattern. For dentoalveolar features, IIA and UMA revealed the
most acute angle in class II skeletal pattern. In contrast for LMA, class I skeletal pattern had the most acute angle. Most patients with class II skeletal pattern were found with high angle vertical dimension and acute interincisal angle and upper molar angulation which indicated high anchorage demand and long-term retention after orthodontic treatment