IADR Abstract Archives
Residual Ridge Resorption and Peri-implant Strain in Mandibular Implant Overdenture
Objectives: There is little information of the relationship between the posterior residual ridge resorption and the strain around implant. The purpose of this study was to examine the influence of posterior residual ridge resorption and relining procedure on peri-implant bending strain under implant overdenture.
Methods: Two tissue level implants were used. Four strain gauges were attached on four surfaces of each implant. One mandibular and one maxillary edentulous model were made and covered by silicone rubber with 2-4mm thickness to simulate the oral mucosa. Next, two implants were installed bilaterally in the area between the mandibular canines and lateral incisors. Maxillary conventional denture and mandibular overdenture were made for fitting the edentulous models. Locator attachments were used in this study. Three levels of posterior ridge resorption (0mm, 1mm and 1.5mm) were set in the same model. Simulated mucosa with 2-4mm thickness was made. After measuring bending strain in 1.5mm level, relining procedure was performed with direct technique. A 98N occlusal force was applied to mandibular overdenture through the maxillary denture. Each measurement of bending strain was recorded for ten seconds in five times. Bending strains were compared among three levels of posterior ridge resorption and relining for 1.5mm level. Kruskal–Wallis test and Bonferroni’s test for multiple comparison were conducted with significant level at 0.05.
Results: Bending strain at no ridge resorption was significantly smaller than at 1mm and 1.5mm resorption (p<0.05); while there was no significant difference in bending strain between no ridge resorption and after relining (p>0.05).
Conclusions: As posterior residual ridge resorption progressed without relining, bending strain increased. This might affect bone resorption around implants. Since there was no significant difference in bending strain between no ridge resorption and after relining, the importance of reline was confirmed.
Methods: Two tissue level implants were used. Four strain gauges were attached on four surfaces of each implant. One mandibular and one maxillary edentulous model were made and covered by silicone rubber with 2-4mm thickness to simulate the oral mucosa. Next, two implants were installed bilaterally in the area between the mandibular canines and lateral incisors. Maxillary conventional denture and mandibular overdenture were made for fitting the edentulous models. Locator attachments were used in this study. Three levels of posterior ridge resorption (0mm, 1mm and 1.5mm) were set in the same model. Simulated mucosa with 2-4mm thickness was made. After measuring bending strain in 1.5mm level, relining procedure was performed with direct technique. A 98N occlusal force was applied to mandibular overdenture through the maxillary denture. Each measurement of bending strain was recorded for ten seconds in five times. Bending strains were compared among three levels of posterior ridge resorption and relining for 1.5mm level. Kruskal–Wallis test and Bonferroni’s test for multiple comparison were conducted with significant level at 0.05.
Results: Bending strain at no ridge resorption was significantly smaller than at 1mm and 1.5mm resorption (p<0.05); while there was no significant difference in bending strain between no ridge resorption and after relining (p>0.05).
Conclusions: As posterior residual ridge resorption progressed without relining, bending strain increased. This might affect bone resorption around implants. Since there was no significant difference in bending strain between no ridge resorption and after relining, the importance of reline was confirmed.