Aim: This systematic review of randomized controlled trials (RCTs) aims to answer to the following question: "In patients undergoing dental implant placement, which is the best antibiotic prophylaxis protocol to prevent early failures?" Materials and Methods: The MEDLINE, SCOPUS, CENTRAL and Web of Knowledge electronic databases were searched in duplicate for RCTs up to July 2017. Additional relevant literature was identified through (i) handsearching on both relevant journals and reference lists, and (ii) searching in databases for grey literature. A network metaanalysis (NMA) was conducted, and the probability that each protocol is the "Best" was estimated.Results: Nine RCTs were included, with a total of 1,693 participants. Due to the few events reported, it was not possible to conduct a NMA for adverse events, therefore it was conducted only for implant failures (IF). The protocol with the highest probability (32.5%) of being the "Best" one to prevent IF was the single dose of 3 g of amoxicillin administered 1 hr pre-operatively. Even if the single pre-operative dose of 2 g of amoxicillin is the most used, it achieved only a probability of 0.2% to be the "Best" one. Conclusions:Basing on the available RCTs, the use of antibiotic prophylaxis is protective against early implant failures. Whenever an antibiotic prophylaxis is needed, there is still insufficient evidence to confidently recommend a specific dosage. The use of post-operative courses does not seem however to be justified by the available literature. Prospero registration number: CRD42015029708. K E Y W O R D S adverse events, antibiotic prophylaxis, early failures, early implant failures, implant placement, implant survival, network meta-analysis, penicillins, side effects, systematic review | 383 ROMANDINI et Al.

A novel, direct and independent association between sleep duration and the prevalence of periodontitis was found. However, it needs to be investigated how the factors influencing the sleep duration affect this association.

Within the limitations of this study, periodontitis-especially severe-is independently associated with a considerable increase in platelet count which is explained, at least in part, by an increase in the systemic inflammation.

Aim While the short‐term effects of hormonal events on gingival inflammation have been well described, long‐term effects on the periodontium have received less attention. The aim of this cross‐sectional population‐based study was to evaluate the association between hormone‐related events and periodontitis in a representative sample of the postmenopausal women of South Korea. Materials and Methods A total of 10,273 postmenopausal women representative of 6.1 million of Koreans were examined. Periodontitis and severe periodontitis were defined according to the Community Periodontal Index (CPI ≧ 3 and CPI = 4, respectively). Univariate and multivariate regression analyses using 3 different models were applied controlling for age, smoking, marital status, educational level, income, BMI, hypertension, stress and frequency of toothbrushing. Results Severe periodontitis was directly associated with a longer reproductive life (p‐trend = .027) and with a longer duration of breastfeeding (48–72 vs. 1–17 months: OR = 1.49; 95% CI: 1.01–2.21). Conversely, early menopausal age (<46 vs. 49–50 years: OR = 0.74; 95% CI: 0.56–0.97), history of artificial menopause (OR = 0.72; 95% CI: 0.53–0.97), having had more than 6 pregnancies (vs. 4: OR = 0.73; 95% CI: 0.55–0.97), having had more than three abortions (vs. 0: OR = 0.51; 95% CI: 0.28–0.93) and having had the first birth age >26 years (vs. <21 years: OR = 0.71; 95% CI: 0.52–0.97) were inversely associated with severe periodontitis. Conclusions In this large nationally representative population, severe periodontitis was related to menopausal age, reproductive life length, number of pregnancies/abortions, first birth age and breastfeeding duration, while it was not to oral contraceptive and hormone replacement therapy usages.

Background: Air pollutants can influence local and systemic inflammation, oxidative stress and microbiome composition. Therefore, air pollution may potentially represent an unexplored modifiable risk indicator for periodontitis. The aim of the current cross-sectional study was to investigate the epidemiological association between outdoor air pollution and periodontitis in a representative sample of the South Korean population. Methods: A total of 42,020 individuals, which were representative of 35.2 million South Koreans, were examined. The mean annual levels of particulate matter of 10 μm (PM10), ozone, sulfur dioxide (SO2), nitrogen dioxide (NO2) and humidity, were studied. Periodontitis was defined according to the Community Periodontal Index (CPI ≥ 3). Simple and multiple regression analyses using four different models were applied. Results: Every 5-μg/m3 increase in PM10 (OR = 1.17; 95% confidence interval—CI: 1.11–1.24) and of 0.005 ppm in ozone levels (OR = 1.4; 95% CI: 1.00–1.30) were positively associated with periodontitis prevalence. Conversely, every 5% increase in humidity (OR = 0.94; 95% CI: 0.90–0.99) and 0.003 ppm increase in NO2 levels (OR = 0.93; 95% CI: 0.89–0.96) were inversely associated with periodontitis occurrence. Conclusions: In this nationally representative population several air pollutants were found to be associated with periodontitis occurrence. Hence, the present results suggest that air pollution may be a new modifiable risk indicator for periodontitis.