SUMMARYBackground. Titanium is the gold standard for dental implants, since it has demonstrated excellent biocompatibility and osseointegration properties. The rate of osseointegration is however affected by the surface morphology and peri-implant infections may affect fixture and the long-term osseointegration outcome. Thus chemical composition of a coating at the implant-abutment junction (IAJ) surface is expected to play a key role in preventing bacterial infection. Purpose. In the present study a new antimicrobial polysiloxane coating functionalized with chlorexidine digluconate (PXT) has been tested in an in vitro model. Materials and methods. Twenty implants were coated in the internal chamber with PXT and twenty were used as controls. Results and conclusions. Ten of the coated implants, preliminarily tested against Gram positive and negative bacteria and fungi, showed a complete inactivation of the microbial species after a 15 min contact. On the remaining ten treated implants a series of microbiological tests and PCR analysis, after contamination of the implant external medium, in which the implant have been immersed, with genetic modified Tannerella forsythia (TF) and Porphyromonas Gingivalis (PG), leads to the conclusion that the coating is capable of inactivating the microbial species penetrating the internal of the implant through the implant abutment junction.

The indication for using chemical devices as an adjunct of domestic oral hygiene has gained increased attention in last decades. The efficacy of chemical devices for oral biofilm control is proven by evidence from clinical studies. The purpose of this study was to assess the effect of a new oral gel named ADC to reduce oral bacterial loading investigated by means of Polymerase Chain Reaction (PCR). Materials and methods A total of 20 patients with a diagnosis of chronic periodontitis in the age group >25 years, were selected. None of these patients had received any surgical or non-surgical periodontal therapy and demonstrated radiographic evidence of moderate bone loss. The study sample was divided into two groups of 10 patients each, homogeneous by age and sex. The study group was given a little bottle containing ADC gel, while the control group was given an identical pack-containing placebo, a gel similar to ADC for consistence, colour, taste and odour. Four sites in separate quadrants were selected in each patient for testing the efficacy of the new medical device. Microbial analysis (MA) was performed at baseline and at day 15. Paired T-Test was used to detect statistical significant reduction of total bacterial loading and specific bacteria. Results Specimens of subgingival plaque from patients were investigated for the presence of six bacterial species and for total bacterial loading by quantitative PCR. There was a statistically significant reduction total bacterial loading detected pre and post treatment (p= 0.029) in the study group. In the control group the reduction of total bacterial loading was not significant (p= 0,279). The ADC gel did not show any side effects and was not observed to cause discomfort or to produce adverse reactions in time. No patient reported pain, burning, tingling sensation or numbness. Conclusion The aim of our study was to test the efficacy of a new chemical formulation with antibacterial properties to use for domestic oral hygiene with a preliminary study. Although the reported data show a statistically significant drop in total bacterial loading after treatment our limited results do not allow us to draw final conclusions about the clinical efficiency of the ADC gel. There is currently a trend in the increased use of antimicrobial agents. The effectiveness of antimicrobial therapies depends on host defence mechanisms and virulence factors. Further research, with relatively larger sample size and longer follow-up period, will be performed to better validate the efficacy of ADC gel as an effective local drug delivery agent in daily oral hygiene.