In vitro fluoride release and the antibacterial effect of glass ionomers containing chlorhexidine gluconate.

Fluoride release from glass-ionomers (GI) may be important for the prevention of secondary caries. The addition of chlorhexidine gluconate (CHX) to glass-ionomer cement (3%) adds an effect that enables it to be used as a varnish for the temporary coating of surfaces at risk for caries. This study investigated the fluoride release pattern and antibacterial effect of such a material. Glassionomer luting cement powder (Aqua-Cem) was mixed with water, 10% CHX or 10% CHX with 11% tartaric acid (TA), respectively, to test specimens (6 X 1.5 mm). After setting, the specimens were immersed in 10 ml deionized water and transferred to new vials after various intervals over a period of two months. The antibacterial effect towards mutans streptococci was assessed using agar diffusion. The fluoride release was measured after two hours and after shifting the specimens to new vials 10 times during the two-month period. The mean total fluoride release was 69.02, 50.64 and 48.56 microg/cm2 from each specimen in the GI, GI-CHX and the GI-CHX-TA groups, respectively. For two-hour old specimens, the mean inhibition zone was 0, 50, 36 mm2 in the GI, GI-CHX and GI-CHX-TA groups, respectively, and, after two months, 45 mm2 in the GI-CHX group and 19 mm2 in the GI-CHX-TA group. It can be concluded that the addition of CHX and CHX-TA adds antibacterial properties to GI and the release of fluoride is decreased.

Transient reduction of mutans streptococci on tooth surfaces using a chlorhexidine-containing glass ionomer cement varnish.

Chlorhexidine (CHX) has been incorporated in polymer-based varnishes to reduce mutans streptococci (ms) by the sustained release of CHX. Such varnishes often adhere well to teeth initially but are easily peeled off. To be effective, repeated application is necessary. Glass ionomer (GI) cements interacts with tooth minerals to form a stronger bond, and the inherent brittleness of the cement makes it difficult to remove in large fragments. The fluoride content may also reduce demineralisation. The aim of this study was to observe whether ms could be reduced interproximally and in saliva by a single application of a GI cement containing 3.3% CHX gluconate (CHX-GI). After professional tooth cleaning and a mouth rinse for 2 min with 0.2% CHX, the teeth of six subjects were coated with CHX-GI cement. An additional six subjects were treated with a GI cement that did not contain CHX, and seven subjects received professional tooth cleaning only. Ms samples were taken interproximally with the tooth pick method before and after treatment. Interproximal levels were classified according to the number of colony-forming units (c.f.u.) found: 0, 1-20, 21-100, and > 100. Saliva ms were sampled with the Strip Mutans method. After four weeks, the interproximal levels of ms had decreased only in the CHX-GI group (p < 0.05). In this group 9 of 14 highly colonised sites (> 100 c.f.u.) remained reduced throughout this period. In the GI and the untreated group a slight increase of ms interproximally was seen after one week. The interproximal ms scores in all groups approached baseline levels after 8 weeks. There were no significant differences in saliva ms levels between the groups during the test period. GI cement may be a possible vehicle for CHX in reducing ms interproximally.

Fissure penetration and antibacterial effect in vitro of a glass ionomer cement containing chlorhexidine gluconate.

Chlorhexidine has been incorporated in different varnishes to provide a slow release system on the tooth surface in order to reduce mutans streptococci. To provide an alternative vehicle for chlorhexidine with better adhesion properties compared to resin-based varnishes, glass ionomer cement (GI) has been suggested. However, one disadvantage for glass ionomers is a longer setting time compared to the resin-based varnishes. The aim with this study was to compare the fissure penetration and antibacterial characteristics of a glass-ionomer cement (GI) with a GI containing chlorhexidine gluconate (GI-CHX), and GI-CHX with added tataric acid (GI-CHX-TA) to reduce its setting time. Antibacterial properties against mutans streptococci were assessed by agar diffusion. GI, GI-CHX and GI-CHX-TA were applied with a microbrush on the occlusal surfaces of 4, 4 and 6 extracted molars respectively. After setting of cements, sections were ground with 1 mm intervals and photographed. The fissure penetration and adaptation of the cements were scored excellent, acceptable or unacceptable under blind conditions according to a standard. Seventy percent scored excellent with GI-CHX-TA (n = 54) compared with 40% with GI-CHX (n = 48) and 38% with GI (n = 40), (p < 0.05). GI-CHX and GI-CHX-TA had significant better antibacterial properties compared to GI or GI with added tataric acid only.

Evaluation of a simplified method for site-specific determination of mutans streptococci levels.

To determine the oral mutants streptococcal "load" of an individual, saliva samples reflecting the number of colonized tooth surfaces, are often applied. Sometimes a plaque sample from a specific site would be an advantage, for example in connection with local antimicrobial treatments. The aim of the present paper was to evaluate a chairside method for determination of mutans streptococci interproximally. One hundred subjects participated. Four approximal tooth surfaces of each individual were sampled using toothpicks. The toothpicks were then let to contaminate a pad on a specially designed plastic strip and, for comparison, a MSB-agar plate. The strips were incubated in the standard "Strip mutans" broth. The yield of colony forming units on the strip surface corresponded significantly with that on agar plates. Being a simple chair-side method for the evaluation of the site-specific load of mutans streptococci, it is suggested that the method will be used in various investigations to clarify its potential in different clinical situations.