Evaluation of arch formamong differentclasses of Angle’smalocclusionson dental cast of orthodontic Patientstreatedinjimma medical centerdental clinic Orthodontic unit , jimma, south westethiopia-2022.

Abstract

BACKGROUND: The dental arch form evaluation has become an important part of the orthodontic treatment planning.The way the teeth are aligned on the basal bone determines the archform of an individual. In fact, theArchform varies between two groups and two individuals of the same group.Differences in the archform are seen between males and females. Mismatch of archform leads to expansion or contraction of archforms and hence a relapse of the corrected malocclusion due to functional instability or structural imbalance is a possibility. Evaluating the archform of an individual plays a key role for an Orthodontist in treatment planning and attaining a greater post treatment stability. OBJECTIVES: To asses dental arch form amongdifferent classes of angle’s malocclusions on dental cast of orthodontic patients treated in jimma medical center dental clinic orthodontic unit,jimma, south west Ethiopia, 2022. METHODS;A two years hospital based retrospective cross-sectional study design was conducted to assess arch form of orthodontic patients in jimma university dental clinic fromFebruary to May 2022.Data was collected by reviewing the medical record of patients who visited the orthodontic clinic from February 2020 to March 2022.the dental casts of patients who fulfill inclusion criteria was selected from a pool of available models at orthodontic clinic.Digitalvernier caliper will be used for measurements .The collected data was cleaned, coded and entered to Statistical Package for Social (SPSS version 24) windows software computer program for analysis.SD,mean,T-test and chi square were used to analyze the results. RESULT AND DISCUSSION:The commonest arch form is Ovoid in both arches (upper arch(44.9%) and lower arch(45.7) followed by Tapered and Square arch form; Among gender females has higher in ovoid and tapered arch form, in contrary males has higher in square arch form. The results of this study showed that the commonest class was class I (51.2%), followed by class II (33.9%) and class III (14.9%). Significantly, more females had Class I (p<0.01) and Class II (p<0.05) occlusal relationship compared with males. In upper arch Class III arches is narrower than Class I and Class II dental arches are the widest (p<0.05). In lower arch Class II arches, are Wider than Class I and Class III dental arches. CONCLUSION AND RECOMMENDATION:The most frequently seen arch form in maxillary arch was the Ovoid (44.9%) and Tapered (30.7% ). the least frequent one was the square one which is recorded 24.4%. 6.5%.In mandibular arch 30.7% of subjects have tapered and 45.7% ovoid. the least common arch form is the square which is recorded in 23.6%.The commonest class was class I (51.2%), followed by class II (33.9%) and class III (14.9%). Significantly, more females had Class I (p<0.01) and Class II (p<0.05) occlusal relationship compared with males. more females had Class III relation compared with males. The mean values of all width and depth measurements were higher in males than in females in both arch. the professional’s should select the proper arch wire form based on individual patients arch forms.Further studies is still needed to overcome the limitations of this study which includes studying a larger sample and including other methods of arch form determination and different age groups are needed before the results of the present study can be applied on Ethiopian population