Microbiota Associated with Osseointegrated Implants Restored with Sloping Shoulder and Platform Switched Implants

Introduction: The implant abutment connection is an important factor regarding peri-implant bone remodeling as the highest number of inflammatory cells has been observed at the implant-abutment interface. Supracrestal implant position favours the establishment of biological width at the crest sweeping away the microgap and bacterial contamination at the bone crest thereby reduces inflammatory infiltrate. When supracrestal implant installation is done absence of microgap at the bone crest level and reduced inflammatory peri implant cells with minimal bone loss is seen. Among the parameters that can influence crestal bone levels around implants restored with sloping shoulder and platform switching, the composition of the submucosal peri-implant microbiota has been seldom investigated. Therefore, the aim of the present study is to evaluate the bacterial colonization in dental implants inserted in crestal or supracrestal position and correlated it to radiographic measurements of bone remodeling.

Materials and Methods: A prospective, randomized parallel clinical trial with 24 subjects who required single-tooth rehabilitations were enrolled in the Group 1 which included 12 subjects with sloping shoulder implants placed 2 mm subcrestal level & Group 2 included 12 subjects with platform switched implants placed crestal level. Radiographic examination was performed at baseline (implant installation) and after 6 months. Clinical and microbiological data were collected after 6 months. Digital radiography was used to assess bone remodeling (marginal bone loss and optical alveolar density). Bacterial profile was analyzed by checkerboard DNA- DNA hybridization, including a panel of 40 bacterial species.

Results: We found higher counts of P. gingivalis, T. denticola, T. forsythia (red complex) at crestal level when compared to subcrestal position and it was least at tooth site. The values of bone remodeling at baseline and after 6 months was statistically significant (p < 0.05) in both the groups, also there was statistically significant difference in bone levels at T2 between crestal and subcrestal groups.

Conclusion: The present study results shows that sloping shoulder design with subcrestal implant insertion had significantly less red bacterial complex and bone loss at 6 months post insertion. Platform switched implants showed significantly higher red complex and bone loss.