Periodontal and systemic responses in various mice models of experimental periodontitis: respective roles of inflammation duration and Porphyromonas gingivalis infection.

BACKGROUND: The great variability of periodontal and systemic responses to experimental periodontitis reflects the inherent pathogenic complexity of mice models and could limit the resulting interpretations and their extension to human diseases. This study compared the effect of Porphyromonas gingivalis (Pg) infection and experimental periodontitis duration at local and systemic levels in various models. METHODS: Periodontitis was induced in C57BL/6J mice by ligatures previously incubated with Pg (LIGPG group) or not (LIG group) or by oral gavage (GAV) with Pg ATCC 33277. Blood samples were taken, and mice were euthanized at different times. Periodontal tissue destruction, osteoclast number, and inflammation were assessed by histomorphometry, tartrate-resistant acid phosphatase histoenzymology, and cathepsin B (CATB) and matrix metalloproteinase 9 (MMP9) immunochemistry. Serum levels of interleukin-6 (IL-6) and IL-1ß were measured using enzyme-linked immunosorbent assay bioplex methods. RESULTS: Periodontal tissue destruction and osteoclast numbers were significantly elevated in LIGPG models compared to LIG and GAV models. They increased with time with the exception of osteoclast numbers in the LIG model. CATB and MMP9 expression was related to bone destruction processes and Pg infection. The highest serum levels of IL-6 and IL-1ß were observed in the LIGPG group. A decrease of IL-6 and an increase of IL-1ß serum level were observed with time in LIGPG group contrary to LIG group. CONCLUSIONS: These data indicate that Pg infection worsened periodontal tissue destruction through specific pathogenic pathways and modified systemic response to periodontal inflammation. Furthermore, the blood cytokine response to ligature models showed their relevance for evaluating the systemic impact of periodontal disease.

Long-term implant survival and success: a 10-16-year follow-up of non-submerged dental implants.

OBJECTIVES: The aim of the present study was to evaluate the long-term results of dental implants using implant survival and implant success as outcome variables. METHODS: Of the 76 patients who received 162 implants of the Straumann Dental Implant System during the years 1990-1997, 55 patients with 131 implants were recalled 10-16 years after implant placement for a complete clinical and radiographic examination, followed by a questionnaire that examined the degree of satisfaction. The incidence of biological and technical complications has been carefully analysed for each implant. Success was defined as being free of all these complications over the entire observation period. Associated factors related to peri-implant lesions were analysed for each implant. RESULTS: The long-term implant cumulative survival rate up to 16 years was 82.94%. The prevalence of biological complications was 16.94% and the prevalence of technical complications was 31.09%. The cumulative complication rate after an observation period of 10-16 years was 48.03%, which meant that substantial amounts of chair time were necessary following implant placement. The majority of implant losses and biological complications were concentrated in a relatively small number of patients. CONCLUSION: Despite a relatively high long-term survival rate, biological and technical complications were frequent. Patients with a history of periodontitis may have lower implant survival rates than patients without a history of periodontitis and were more prone to biological complications such as peri-implant mucositis and peri-implantitis.