Relationships Between Facial Form and Alveolar Ridge Height

OBJECTIVES: The purpose of this study was to determine the relationships between facial form and mandibular and maxillary edentulous alveolar ridge height.

METHODS: A randomized controlled clinical trial was undertaken to treat patients with either mandibular conventional (CD) or implant-assisted overdentures (IOD). Post-insertion cephalometric radiographs were assessed for 25 subjects with CD and 44 with IOD. The radiographs were evaluated using Dolphin software (Dolphin 10.0-Dolphin Imaging, Chatsworth CA.). Selected reference values were used for determination of facial form and skeletal classification.

Maxillary alveolar ridge height was determined by the perpendicular bisection of the palatal plane (ANS-PNS) with the most inferior point on the maxillary anterior ridge. Mandibular alveolar ridge height was determined by the perpendicular bisection of the mandibular plane (Go-Gn) with the uppermost point on the symphysis. The ratio of maxillary to mandibular height was calculated. Multivariate analysis of variance (MANOVA) was used to compare the ridge height measures between the 3 facial form categories. Additional univariate analyses and post-hoc tests were performed following the omnibus test.

RESULTS: Significant differences in ridge height were found between facial forms (MANOVA, F=5.79; p<0.001). Univariate analyses showed significant difference in maxillary ridge height (F=13.83, p<0.0001), but no significant differences were found for mandibular ridge height or the calculated ratio of maxillary to mandibular heights (p>0.05). Post-hoc comparisons (REGW) indicated the maxillary ridge height for the brachyfacial group (p<0.05) was significantly less than for mesofacial and dolicofacial groups. No difference in maxillary ridge height was found between mesofacial and dolicofacial groups (p>0.05).

CONCLUSIONS: The maxillary alveolar resorptive ridge pattern was found to be significantly reduced for edentulous patients with a diagnosed brachyfacial facial profile as compared to patients with a mesofacial or dolicofacial facial form. Further evaluation of these relationships is indicated for clinical impact and relationship with available treatment modalities.