Background and Aim
Peri-implantitis presents with loss of surrounding supporting bone around implants. Reported prevalence of peri- implantitis varies, with differing definitions and study conditions. The purpose of this study was to evaluate the prevalence of peri-implant bone loss in adults who had opted in for dental examination at general medical examination visit and to investigate the associatoins between local and systemic factors and peri-implant bone loss shown in panoramic radiographs.
Material and Methods
The present study analyzed data from patients who underwent physical examination and opted in for oral examination at a general hospital in 2016. Oral examination included panoramic radiograph taking. A total of 1088 patients had given permission to use their data for research and all the subjects with dental implants shown in the panoramic radiographs (N=307) were included in the study. Number of remaining teeth, age, complete blood count and WBC differential count, blood chemistry, urinalysis, urine chemistry, degree of periodontal bone loss, implant location, implant-abutment connection type, implant length, width were investigated. ANOVA, t-test and chi-square test were used to describe the associations of the location of implant, implant connection type, and other variables with peri-implant bone loss. Logistic regression analysis models were fitted to analyze the variables associated with peri-implant bone loss. Two subjects with one-piece implants were not included in the statistical analysis.
Results
Among the remaining 305 patients with oral implants, 199 patients (65%) did not show greater than 2 mm of alveolar bone loss, and 106 patients (around 35%) had bone loss greater than 2 mm. In this group, 68 patients had slight peri- implant bone loss of 2-3 mm, and 38 patients had greater than 4 mm of peri-implant bone loss.
Blood direct bilirubin levels and phosphorus levels were slightly associated with radiographic peri-implant bone loss. Number of residual teeth (P = 0.0001), and a history of periodontitis (P = 0.0304) had the greatest association with peri- implant bone loss. A total of 904 implants were found and among these, 302 (33.6%) showed greater than 2mm of bone loss. Greater prevalence of bone loss was seen in the maxilla (26.6% > 19.8%) (P<0.05). Odd ratio for bone loss of implants placed in the posterior maxilla 1.45 times higher than those of the posterior mandible. (P<0.05)
Conclusions and Clinical Implications
34% of patients with implants and 33.6% of 904 implants showed 2 mm or greater bone loss. Among the factors affecting bone loss, statistical analysis revealed that the number of remaining teeth, presence of periodontitis, and the progression of periodontitis were significantly associated with bone loss around implants. It would be prudent to be more vigilant in the maintenance phase of dental implant therapy for patients with pre-existing periodontitis.

Radiographic peri-implant bone loss and associated local and systemic factors