Evaluation in vivo of antibacterial activity of two self-etching adhesives

Objectives: The purpose of this study was to evaluate, in vivo, the antimicrobial property of the self-etching adhesive Clearfil Protect Bond (Kuraray) compared to iBond NG plus B (Heraeus) by a highly sensitive and specific molecular biology technique as Real-Time PCR,

Methods: Adult patients with two Class I carious lesions in opposite quadrant sections (split mouth study design) were selected and carious lesions were restored (n=18) with two adhesive system tested in each patient. A unique composite material (Venus, Heraeus) was used for all restorations. According to a standardized protocol, plaque samples were collected before restoration as a baseline, then samples were taken after 3 and 6 months. The presence of Streptococcus mutans was analyzed statistically with Mann Whitney test (p=0,05).

The DNA was extracted from all specimens collected and a Real-time PCR was performed to examine the presence of Streptococcus mutans using a specific primer set that amplifies the gtfB gene. In order to quantify the Streptococcus mutans, 5 serial dilutions of a recombinant plasmid (pGEM + gtfB) were used as standard curve. PCR system accuracy for the assay was performed.

An in vitro study was also performed to determine antibacterial effect of the adhesives by microscopic observations utilizing Gram staining method.

Results: Mann Whitney statistical analysis test highlighted a significant Streptococcus mutans pull-up by Clearfil Protect Bond (p<0.05). Real-Time PCR system accuracy presented a variation intra-assays of 2.38% and inter-assays of 4.52%.

Conclusion: This study showed the efficacy of antibacterial self-etching adhesive (Clearfil Protect Bond) preventing microleakage of Streptococcus mutans at the interface between enamel and resin restoration. On the other hand, we could affirm that a low variation on intra and inter – assays demonstrates the real accuracy of the quantification method of S. Mutans with Real-Time PCR technique.