Prescription of antibiotic prophylaxis in implant placement among Portuguese dentists: A web survey.

OBJECTIVES: This study aims to assess whether antibiotic prophylaxis for dental implant placement is commonly used by dentists in Portugal. MATERIALS AND METHODS: This cross-sectional survey study was based on a web survey with 22 questions divided into 5 parts. The 1st part focused on demographic details, work experience, and academic expertise, whereas the 2nd and 3rd parts were about the pre- and postoperative antibiotic prescriptions. The 4th and 5th parts focused on dentists' motivation for using/avoiding antibiotic prophylaxis and the use of a protocol, respectively. Data interpretation included descriptive analysis and statistical inference via cross-tabling with chi-square adjusted standardised for residual effects. RESULTS: Of the 204 valid surveys, at least one was received from every large Portuguese city which ensured the national coverage of the survey. Most respondents are not specialist dentists (72%). Sixty-four percent of the respondents always use antibiotic prophylaxis, while 29% adopt it only when grafting materials are employed. Most respondents use both pre- and postoperative regimens (55%). Amoxicillin 875 mg + clavulanic acid 125 mg is the most prescribed antibiotic (57%). Finally, the risk reduction of postoperative infection is the most frequent justification for the use of antibiotic prophylaxis (60%). CONCLUSIONS: The results highlight that most of the respondents do not follow the consensual international guidelines for prophylactic antibiotherapy in dental implant placement surgeries. This finding should serve as a rationale to increase the dissemination of those guidelines.

Comparative gene expression analysis of Porphyromonas gingivalis ATCC 33277 in planktonic and biofilms states.

BACKGROUND AND OBJECTIVE: Porphyromonas gingivalis is a keystone pathogen in the onset and progression of periodontitis. Its pathogenicity has been related to its presence and survival within the subgingival biofilm. The aim of the present study was to compare the genome-wide transcription activities of P. gingivalis in biofilm and in planktonic growth, using microarray technology. MATERIAL AND METHODS: P. gingivalis ATCC 33277 was incubated in multi-well culture plates at 37°C for 96 hours under anaerobic conditions using an in vitro static model to develop both the planktonic and biofilm states (the latter over sterile ceramic calcium hydroxyapatite discs). The biofilm development was monitored by Confocal Laser Scanning Microscopy (CLSM) and Scanning Electron Microscopy (SEM). After incubation, the bacterial cells were harvested and total RNA was extracted and purified. Three biological replicates for each cell state were independently hybridized for transcriptomic comparisons. A linear model was used for determining differentially expressed genes and reverse transcription quantitative polymerase chain reaction (RT-qPCR) was used to confirm differential expression. The filtering criteria of ≥ ±2 change in gene expression and significance p-values of <0.05 were selected. RESULTS: A total of 92 out of 1,909 genes (4.8%) were differentially expressed by P. gingivalis growing in biofilm compared to planktonic. The 54 up-regulated genes in biofilm growth were mainly related to cell envelope, transport, and binding or outer membranes proteins. Thirty-eight showed decreased expression, mainly genes related to transposases or oxidative stress. CONCLUSION: The adaptive response of P. gingivalis in biofilm growth demonstrated a differential gene expression.