Peri-implantitis increases the risk of medication-related osteonecrosis of the jaws associated with osseointegrated implants in rats treated with zoledronate.

This study evaluated the peri-implant tissues under normal conditions and under the influence of experimental peri-implantitis (EPI) in osseointegrated implants installed in the maxillae of rats treated with oncologic dosage of zoledronate. Twenty-eight senescent female rats underwent the extraction of the upper incisor and placement of a titanium dental implant (DI). After eight weeks was installated a transmucosal healing screw on DI. After nine weeks, the following groups were formed: VEH, ZOL, VEH-EPI and ZOL-EPI. From the 9th until the 19th, VEH and VEH-EPI groups received vehicle and ZOL and ZOL-EPI groups received zoledronate. At the 14th week, a cotton ligature was installed around the DI in VEH-EPI and ZOL-EPI groups to induce the EPI. At the 19th week, euthanasia was performed, and the maxillae were processed so that at the implanted sites were analyzed: histological aspects and the percentage of total bone tissue (PTBT) and non-vital bone tissue (PNVBT), along with TNFα, IL-1ß, VEGF, OCN and TRAP immunolabeling. ZOL group presented mild persistent peri-implant inflammation, higher PNVBT and TNFα and IL-1ß immunolabeling, but lower for VEGF, OCN and TRAP in comparison with VEH group. ZOL-EPI group exhibited exuberant peri-implant inflammation, higher PNVBT and TNFα and IL-1ß immunolabeling when compared with ZOL and VEH-EPI groups. Zoledronate disrupted peri-implant environment, causing mild persistent inflammation and increasing the quantity of non-vital bone tissue. Besides, associated with the EPI there were an exacerbated inflammation and even greater increase in the quantity of non-vital bone around the DI, which makes this condition a risk factor for medication-related osteonecrosis of the jaws.

Multiple aPDT sessions on periodontitis in rats treated with chemotherapy: histomorphometrical, immunohistochemical, immunological and microbiological analyses.

BACKGROUND: The aim of this study was to evaluate the effect of multiple sessions of antimicrobial photodynamic therapy (aPDT) on the treatment of experimental periodontitis (EP) in rats treated with chemotherapy. METHODS: Chemotherapy using 5-fluorouracil (5-FU) consisted of intraperitoneal administration of 60 and 40 mg/kg of 5-FU. 120 rats were subjected to chemotherapy with 5-FU and divided into groups: PT (periodontal treatment); PT+1aPDT (PT and single aPDT session); PT+4aPDT(PT and 4 sessions of aPDT); 1aPDT (single aPDT session); 4aPDT(4 sessions of aPDT). EP was induced in the mandibular molars via ligature placement. The alveolar bone loss (ABL) area in the furcation region was analysed histometrically. Proliferating cell nuclear antigen (PCNA), tartrate-resistant acid phosphatase (TRAP), receptor activator of nuclear factor kappa-B ligand (RANKL), osteoprotegerin (OPG) and cleaved caspase-3 (CC3) were analysed by immunohistochemistry. Prostaglandin E2 was quantified using an ELISA, tumor necrosis factor (TNF)-α and interleukin (IL)-6 were assessed using a multiplex method. The prevalence of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella nigrescens, Prevotella intermedia and Fusobacterium nucleatum was assessed using PCR. The data were statistically analysed (P < 0.05). RESULTS: The PT+4aPDT group showed lower ABL than the PT or 1aPDT groups on day 7. Rats treated with aPDT showed a higher number of PCNA-positive cells with reduced immunolabeling of RANKL. Significant reductions in Prevotella nigrescens were observed in the PT+4aPDT group and in Aggregatibacter actinomycetemcomitans for the 1aPDT and 4aPDT groups. CONCLUSION: Repeated sessions of aPDT as an adjunct or alternative therapy were effective at reducing ABL, regulating bone metabolism, and reducing Prevotella nigrescens and Aggregatibacter actinomycetemcomitans.

Influence of antimicrobial photodynamic therapy as an adjunctive to scaling and root planing on alveolar bone loss: A systematic review and meta-analysis of animal studies.

BACKGROUND: The study aimed to evaluate the effect of antimicrobial photodynamic therapy (aPDT) as adjunctive therapy to scaling and root planing in experimental periodontitis in rats, with or without systemic involvement, by means of histometric analysis of the furcation region. METHODS: Systematic search was done using PubMed/MEDLINE, SCOPUS, EMBASE and ProQuest databases. Quantitative analysis of alveolar bone loss, with subcategories for the experimental periods studied, was performed. The analysis was performed through the mean difference (MD), with 95% confidence intervals (CIs) and according to SYRCLE guidelines. RESULTS: Nine studies were considered eligible. A statistically favorable difference was observed for the use of aPDT in all periods studied in systemically healthy animals at 7 (P < 0.00001; MD: -0.71; 95% CI: [-0.85, -0.58]; I2: 90%), 15 (P < 0.00001; MD: -0.49; 95% CI: [-0.62, -0.37]; I2: 88%), and 30 (P < 0.00001; MD: -0.53; 95% CI: [-0.65, -0.41]; I2: 80%) days postoperatively. The difference was also observed for modified animals at 7 (P < 0.00001; MD: -1.03; 95% CI: [-1.43, -0.62]; I2: 97%), 15 (P < 0.00001; MD: -1.04; 95% CI: [-1.62, -0.46]; I2: 99%), and 30 (P < 0.00001; MD: -0.88; 95% CI: [-1.37, -0.39]; I2: 97%) days postoperatively. CONCLUSION: The adjunctive use of aPDT favored the reduction of alveolar bone loss in experimental periodontitis in rats, and this result was more evident in systemically compromised rats.