Assessment of Dimensional Disparity in Posterior Arch Width Between Opposing Maxillae and Mandibles in Completely Edentulous Patients with Increased Resorption and Edentulous age - An in vivo Study

Aim: To assess the dimensional disparity in arch width between opposing maxillae and mandibles with edentulous age and increased resorption in edentulous subjects wearing complete denture. Materials and Method: One hundred edentulous subjects wearing complete denture were selected for the study. Maxillary and mandibular casts and a panoramic radiograph were made for each subject. The original height of the mandible before loss of teeth and resorption was predicted by multiplying the distance between the inferior border of the mandible to the lower edge of the mental foramen by a factor of 2.9. The reduction in height of the edentulous mandible was expressed as percentage of the original height of the mandible. The maxillary arch widths immediately anterior to the tuberosities and mandibular arch widths immediately anterior to the retromolar pads were measured. The difference between these two measurements was calculated to determine the discrepancy in posterior arch width. Results: There was no statistically significant difference in the mean values of posterior arch width discrepancy for different groups of edentulous age as well as percentage resorption. The differences in the mean values for amount of resorption with edentulous age were statistically significant. Conclusion: The discrepancy in posterior arch width between opposing maxillae and mandible does not increase progressively with edentulous age and increased reduction in mandibular height. The arch width of the mandible exceeds the arch width of the maxillae in the molar region by an average of 6 to 8 mm after sufficient resorption establishes a definitive alveolar crest. This remains constant regardless of the amount of resorption or edentulous age. The mandibular ridge reduction is found to increase with edentulous age.