Crestal bone loss adjacent to oral implants in older and younger adults

Objective: Older adults are at increased risk of oral bone loss. The objective of this study was to compare older and younger adults on the basis of crestal bone behaviour adjacent to their oral implants. Methods: A comparison was made between closely matched groups of 32 older adults with 166 implants to support 35 complete oral prostheses and 34 younger adults with 162 implants to support 35 complete oral prostheses. Results: No statistical significance could be attributed to the difference in cumulative implant success between the groups throughout the study period over 4 to 17 years after prosthetic loading. Nor could statistical significance be attributed to the difference between the groups in terms of mean annual crestal bone loss among the prosthetic sites after the first year of loading, 0.043 mm per year for the older group and 0.041 mm per year for the younger group. However, after the fourth year the older fixed mandibular prosthesis sub-group demonstrated a significantly lower rate of bone loss (p<.05 using a Mann-Whitney Test), 0.005 mm per year, compared to the younger fixed mandibular prosthesis sub-group, 0.047 mm per year. Notably, the older sub-group sites had been edentate for 25.0 years at implant placement compared to only 13.6 years for the younger group sites, also a significant difference (p<.05 using a Mann-Whitney Test), suggesting that younger complete implant prosthesis patients who have been edentate for shorter periods may be more susceptible to peri-implant bone resorption than older patients who have been edentate for longer periods. Conclusion: Older adults should expect a mean annual crestal bone loss adjacent to oral implants in completely edentulous jaws to be no greater than that seen in younger adults. Additional studies are needed to supplement this conclusion in the context of a wider diversity of ages, jaw sites and prosthetic applications.