Impact of Restorative Emergence Profiles on Peri-Implant Bone Level

Objectives: Our goal is to assess the emergence profiles of implant abutmentsand crowns, and examine their relationship with peri-implant bone level.
Methods: Patients who had single tooth implants placed and restored at UTHealth School of Dentistry were included in this study. These implants had to have one or two adjacent, unrestored natural teeth present and have periapical radiographs at implant placement, crown delivery, and at least 6-month follow-up. All patient and clinical information was extracted from the electronic health record. The emergence profiles of teeth implant abutments, implant crowns and peri-implant bone levels were measured from each peri-apical radiograph using ImageJ software. Generalized linear model was used to analyze the associations between marginal bone level change and variables by adapting Gaussian distribution. Marginal bone level at the mesial and the distal sites were analyzed respectively. Demographic (age, gender) and clinical variables (probing depth, bleeding on probing, implant site and width, contact and implant platform position, abutment height and profile, restoration and tooth contour) were included in the analysis. The categorical variables used one-hot representation for conveying binary information. The missing value of each continuous variable used median value for imputation.
Results: Ninety-seven patients were included. In the simple linear regression model, the deepest probing depth was the only variable significantly associated with both mesial marginal bone level change (coefficient =-0.10±0.05, p=0.04) and distal marginal bone level change (coefficient =-0.23±0.08, p<0.01). In the final regression model, mesial marginal bone level was associated with female (coefficient =0.23±0.14, p=0.09) and the deepest probing depth (coefficient =-0.08±0.03, p=0.02). Distal marginal bone level was associated with female (coefficient =0.36±0.22, p=0.10), the deepest probing depth (coefficient =-0.23±0.05, p<0.01), and the platform position (coefficient =0.08±0.04, p=0.03).
Conclusions: These results indicate that marginal bone loss may be affected bythe depth of implant platform position.