Mandibular residual ridge morphology in relation to complete dentures and implant overdentures-Part I: Predictors for perceived conventional denture stability.

BACKGROUND: There is lack of reliable predictors for success of conventional complete denture (CCD) therapy, which in turn might affect the effectiveness of subsequent implant-retained overdenture (IOD) therapy. PURPOSE: To investigate relationships between digitally obtained geometrical mandibular residual ridge measures and perceived CCD-stability. MATERIALS AND METHODS: 30 CCD wearing patients (67.9 ± 7.0 years) for whom a new set of CCDs was advised, were treated with new CCDs. Digitalized mandibular gypsum models were measured using the Geomagic Studio 2013 software. Data were obtained for (1) height, width, and cross-section surface area of the residual ridge at different locations (midline, premolar, and anterior edge of retromolar pad) and (2) denture base surface area. Scatter plots and multivariate regression analyses were used to investigate associations between the geometric data and denture base surface area, and correlated with denture stability scores (Spearman rank test). RESULTS: Scatter plots showed that best model fit for denture base surface area was mean ridge height (R2 = 0.906). Multivariate regression showed that height at premolar location (p = 0.001) had largest effect on denture base surface area (R2 = 0.796). Ridge morphology variables, except width at midline location, were significantly correlated with CCD-stability (p-values <0.05). CCD-stability was significantly correlated with denture base surface area (p ≤ 0.001). CONCLUSION: Residual ridge height at premolar location was most predictive for denture base surface area and perceived CCD-stability.