Analysis of the changes in components of smile after maxillary arch distalization using infra-zygomatic crest (IZC) screws – A cephalometric and photographic study

The purpose of this study was to analyze the effects of infra-zygomatic crest (IZC) screws on smile components after maxillary arch distalization. The study was conducted on 20 subjects (11 boys and 9 girls) between 19 and 30 years. It was a time-bound study where screening of patients was done based on the inclusion and exclusion criteria for a year. Before placement of orthodontic bone screws (IZC), pre-treatment (T0) photographs, and cephalograms were taken where photographs were analyzed using Makhter’s software. After 6–8 months, post-distalization treatment (T1) photographs and cephalograms were taken and evaluated. Descriptive statistics were used to obtain the mean and standard deviation for continuous data. Paired t-test was performed to analyze the changes in pre- and post-distalization. The categorical data were calculated using the McNemar test. Differences were considered significant if P < 0.05. Inner commissure right and left, smile arc, posterior maxillary dentition visible - left (PMDVL), upper incisal visibility, and gingival showed statistical significance. Maxillary arch distalization using IZC screws was associated with changes in horizontal smile components but mainly in vertical components, reducing the gummy smile, and making the smile esthetically pleasing.