Assessment of Dental Asymmetry Utilizing Orthodontic Study Casts Comparing Tooth Positions to the Midpalatal Raphe and Tooth Size Among Antimeres

Abstract

Several studies have been conducted in relation to the treatment and etiologies of craniofacial and dental asymmetries in the orthodontic scientific literature. However, limited research has attempted to correlate asymmetry in dental traits to each other. The purpose of this research study was to develop a better understanding of the correlations between dental arch asymmetry and dental tooth size asymmetry and their underlying causes. Understanding asymmetries is essential in orthodontic diagnosis and treatment planning. An orthodontist cannot obtain an optimal occlusal and functional result without properly balancing skeletal and dental relationships. Pretreatment dental study casts of 86 sequential patients from the postgraduate orthodontic clinic at the Indiana University School of Dentistry were used for the analysis. Each patient was analyzed in a single blind fashion to minimize bias. The Adobe Photoshop® ruler and Chicago® brand electronic digital calipers accurate to the nearest tenth of a millimeter were used for digital measurements. Measurements were made to determine the amount and direction of asymmetry along the dental midlines relative to the median palatine raphe. Transverse and sagittal measurements were made to record asymmetries in canine and molar positioning. Furthermore, three sets of antimeric maxillary teeth were measured for length and width. These included the central incisors, the canines, and the first molars. Fluctuating asymmetry was present in all measurements, except molar distance to median palatal raphe. This was found to be directional to the left in the entire sample group. Statistical analysis was subsequently performed and the results showed significant correlations in the individuals in the subsample dentition group. Subjects belonging to this group with a measurable degree of fluctuating asymmetry had a greater tendency toward transverse maxillary discrepancies as measured from the canines and first maxillary molars relative to the median palatal raphe. Moreover, individuals in the subsample group with above average total weighted fluctuating asymmetry values according to the parameters analyzed in this study appeared more likely to have decreased developmental stability leading to the clinical expression of more severe malocclusions.