In Vitro Analysis of the Implant-Abutment Interface Connection and Bacterial Infiltration in Two Extraoral Implant Models.

PURPOSE: To compare the connection microgaps and the bacterial infiltration of implant-abutment interfaces of two extraoral implant models. MATERIALS AND METHODS: Two implant models were used: the inner connection and the flush connection types. The implant-abutment microgaps of five sets of each extraoral implant were evaluated with scanning electron microscopy. Eleven additional sets of each model design were immersed in Staphylococcus aureus cultures for 24 hours, and samples were obtained from the external surface and from the implant's internal chamber to quantify the colony-forming units. RESULTS: Scanning electron microscopy analysis showed that microgaps of the flush connection were smaller compared with the inner connection (P < .0001), and that bacterial counts were higher at the inner connection compared with the flush connection (P < .0001). CONCLUSION: Within the limitations of this experimental study, it can be concluded that the flush connection model presented a smaller microgap and fewer bacterial colonies compared with the inner connection model.

Influence of implant-retained silicone oculo-palpebral prosthesis on stress distribution: a pilot study using a photoelastic model.

PURPOSE: The purpose of this pilot study was to evaluate the behavior of stresses surrounding orbital model implants subjected to a load of a silicone oculo-palpebral prosthesis. MATERIALS AND METHODS: A photoelastic model was constructed mimicking the orbital cavity of an adult patient who underwent left orbital resection. Two 3.75 × 5-mm extraoral implants with 3.75 × 5.25-mm magnetic connectors were placed in the model to anchor a silicone oculo-palpebral prosthesis. The stress generated by prosthesis retention was evaluated using photoelasticity at 15, 30, and 60 minutes. The polariscope images were analyzed qualitatively at five areas surrounding the implants. These same areas were analyzed quantitatively using Matlab software based on the RGB color pattern. Data were compared with the Wilcoxon test. RESULTS: Using fringe localization, the qualitative analysis demonstrated that the area between the implants had the greatest stress. The quantitative analysis showed that the peri-implant stress increased significantly in proportion to the increase in prosthesis retention time. CONCLUSION: The oculo-palpebral prosthesis generated stress around the implants, and the stress intensity was directly proportional to the duration of use.