Effects of conventional complete dentures and implant-supported overdentures on alveolar ridge height and mandibular bone structure: 2-year and 6-year follow-up study

Objectives The aim of this study was to compare the changes in mandibular bone structure in edentulous patients who were rehabilitated with conventional complete dentures (CCD) and implant supported overdentures (ISO), by evaluating alveolar bone loss (ABL), panoramic mandibular index (PMI), mandibular cortical width (MCW), gonion index (GI), antegonial index (AI), and articular eminence inclination (AEI). Materials and methods Panoramic radiographs of 63 edentulous patients using CCD, 63 edentulous patients using ISO, and 126 patients without tooth loss were evaluated. Edentulous patients had a 2-year and 6-year follow-up panoramic radiograph image. ABL (anterior, premolar, and molar regions), MCW, PMI, AI, GI, and AEI were measured in each patient. Variation between measurements was analyzed using repeated measures ANOVA test and post hoc Tukey test. Results Both edentulous groups showed significantly lower mean than without tooth lost group in all measures ( p < 0.000). ISO group showed significantly lower mean ABL than CCD group in anterior ( p = 0.000), right premolar ( p = 0.005), left premolar ( p = 0.005), right molar ( p < 0.000), and left premolar ( p < 0.000) regions in short term. ISO group showed significantly lower mean ABL than CCD group in anterior ( p = 0.021), right molar ( p < 0.000), and left premolar ( p < 0.000) regions in long-term. There is no statistically significant difference between the CCD and ISO groups in right premolar ( p = 0.200) and left premolar ( p = 0.134) regions in long term. Both edentulous groups showed significantly lower mean MCW ( p < 0.000), PMI ( p < 0.000), AI ( p < 0.000), GI ( p < 0.012), and AEI ( p < 0.002) than the without tooth loss group. There is no statistically significant difference between the CCD and ISO groups in terms of changes in the mean MCW, PMI, AI, GI, and AEI measurement in short and long term ( p > 0.000). Conclusions In the short and long term, edentulism reduced alveolar crest height, MCW, and AEI in individuals, but had no effect on PMI, AI, or GI. The use of prosthesis did not prevent the decrease of alveolar crest height, MCW, or AEI (CCP or ISO). In the short and long term, however, ISO created less ABL in the mandibular anterior and molar regions than CCD. Clinical relevance ABL cannot be halted in edentulous people, but by using ISO instead of CCD for rehabilitation, resorption can be reduced.