Does mandibular edentulous bone height affect prosthetic treatment success?

Objectives: The aim of this study is to determine whether mandibular bone height affects patients' ratings of satisfaction and function with mandibular 2-implant overdentures (IODs) and conventional dentures (CDs).

Methods: 214 edentulous elders were randomly allocated into 2 groups and treated with maxillary CDs and either mandibular CDs or IODs. Classifications of mandibular bone height were carried out on panoramic radiographs using 4 published methods. At baseline and 6 months after delivery, all participants rated their satisfaction with their prostheses using the McGill Denture Satisfaction Instrument. Independent t-tests and a linear multivariable regression model were used for statistical analyses.

Results: Mandibular bone height has no effect on patients' ratings of general satisfaction, nor on ratings of ability to chew, stability, comfort, aesthetics and ability to speak at 6 months (p>0.05, linear regression). There were significant between treatment differences in ratings of general satisfaction, comfort, stability and ability to chew from all mandibular bone height categories, with higher ratings assigned to IODs (p<0.01, t-tests). Linear regression analyses confirmed that, for general satisfaction, as well as ability to chew, stability, comfort, aesthetics and ability to speak, treatment with IODs contributes to higher satisfaction ratings (p<0.001), while mandibular bone height does not.

Conclusions: The evidence demonstrates that mandibular bone height has no effect on patients' satisfaction with the function, chewing ability and comfort of their prostheses. Furthermore, no matter how much mandibular bone, these results suggest that edentulous elders will benefit more from mandibular IODs than from CDs.