RELATIONSHIP OF VERTICAL PROPORTIONS AND ARCH FORMS IN SKELETAL CLASS II IN A SAMPLE OF LOCAL POPULATION

Abstract

A well-balanced face has its good proportions in all three planes of space, i.e. transverse, sagittal and vertical. The vertical proportions of the face are important in determining the esthetics and har­mony of the face. Dental arch form is a reflection of underlying bone morphology, size and its shape. Correct identification of patient’s arch form is an important aspect of achieving a stable, functional and esthetic orthodontic treatment result. The objective of current study was to determine a relation­ship between vertical proportions and arch form in skeletal class II in local Pakistani population. A sample of 100 nontreated skeletal class II patients fulfilling all the inclusion and exclusion criteria were selected.

Lateral head cephalograms and pre-treatment plaster study models were measured. For each sub­ject, Sella Nasion- mandible plane angle (SN-MP) was measured. Angular measurements and linear relationships were measured manually on both dental arches. Intermolar, inter canine and anterior angle were measured. A weak but significant (r=0.23)correlation between anterior mandibular angle and SN-MP was observed, with increase in SN-MP, the intermolar and intercanine distance was decreased in maxilla and mandibular arch.

Intercanine, intermolar widths and anterior angle values calculated on the maxillary and man­dibular casts of individuals with different facial forms show no significant difference statistically. A weak but significant correlation(r=0.23) was found between anterior mandibular angle and SN-MP.