Comparison of Normalized Facial Form Classification and Masticatory Function

OBJECTIVE: The purpose of this study was to determine the effect of alternate definitions for facial form classification and the effect on observed relationships for form and functional outcomes in dentitions restored with complete dentures supported with and without dental implants.

METHODS: A randomized controlled clinical trial was undertaken to compare treatment success rates, functional and perceptual outcomes, and cost of care with mandibular complete dentures (CD) and implant overdentures (IOD) in average denture wearers. Subjects were evaluated at entry and then received new dentures with either mandibular conventional or implant overdentures. Pre- and post-insertion cephalometric radiographs were taken and evaluated for 25 CD subjects and 44 IOD subjects. The radiographs were evaluated using Dolphin software. (Dolphin 10.0 - Dolphin Imaging, Chatsworth CA.) Specified landmark points were selected for identification by two clinicians for determination of facial form and skeletal classification.

Masticatory performances with two test foods were evaluated using standardized masticatory performance (PS) and swallowing threshold performance (SWT) tests. Comparison of PS and SWT were made between facial groups and treatment-types. Form classifications were made using values normalized for age gender and ethnicity and were compared to classifications developed from non-normalized references values in the literature.

RESULTS: Significant differences were seen in distributions of facial forms (p<0.001) using the two classification methods, with more dolico-facial cases with the normalized method (12%) compared to the non-normalized method (3%). The PS with peanuts was highest in the CD group with mesofacial form (45.1+13.0), compared to brachyfacial (36.4+11.1) or dolicofacial (34.5+13.0) forms. Masticatory performance data for dolico-facial form was lower than for other forms for both normalized and non-normalized classifications, with the non-normalized classification being the lowest..

CONCLUSIONS: Facial form evaluation is a valuable assessment for prosthodontic evaluation of implant treatment and functional profiling.