Cariogenic Potential of Infant Formulas-An In Vitro Study.

Objectives: To compare the in vitro cariogenic potential of two infant formulas (IF, for ages 6-12 months) processed with sterile distilled water with or without 1 ppm fluoride. Study design: Nine specimens in each water type were inoculated with Streptococcus mutans (SM) suspension. The specimens were then divided into one group of samples cultured immediately on Mitis salivarius (MS) agar plates (T0) and another group of specimens cultured on MS agar plates after incubation at 37°C for 4 hours in anaerobic conditions (T4). Six-fold dilutions of each sample were incubated for 48 hours, and colony-forming units (CFUs) of SM were numerated. The pH changes associated with bacterial fermentation of each of the suspensions were measured at T0 and at T4 following incubation. Results: The pH was lower at T4 than at T0 in both IF. The SM colonies increased significantly at T4 compared to T0 in both IF (P < 0.001). There was no significant difference between the CFUs of the mediums at T0 and T4 or relation between SM colonies of IF based on fluoridated and non-fluoridated distilled water. Conclusion: The cariogenic potential was not significantly different between two IF prepared with fluoridated or non-fluoridated distilled water.

Levels of bacterial contamination in fresh extraction sites after a saline rinse.

PURPOSE: To determine the level of bacterial contamination in immediate implantation or augmentation sites vs pristine bone, before and after saline rinses. MATERIALS AND METHODS: Bacterial samples were taken from fresh extraction sites (17 patients) and pristine bone (15 patients) before performing implant dentistry surgical procedures. Levels of bacterial contamination were estimated before and after saline rinses. Samples from the socket were placed on an agar plate for total bacterial account and on selective plates for Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis counts. RESULTS: The level of bacterial contamination before saline rinse was 1.2 × 10(4) units of bacterial colony (CFU)/mL in fresh extraction sites (study group) and 5 × 10(2) CFU/mL in pristine bone sites (control group). After a saline rinse, the bacterial level was lowered significantly to 5.2 × 10(3) CFU/mL in the study group and to zero in the control group (P < .05). Levels of bacterial contamination were higher in the mandibular sockets (7.5 × 10(3) CFU/ml) than in the maxillary sockets (5.6 × 10(3) CFU/mL), and the difference was statistically significant (P = .034). All implanted/augmented fresh or pristine sites survived in the follow-up period. CONCLUSION: Fresh extraction sockets with clinical signs of infection show bacterial presence. Pristine bone shows a lower bacterial level. Saline rinse in addition to a decontamination protocol may reduce the level of bacterial contamination significantly both in fresh extraction sites and pristine bone.

Zinc enhances the phototoxic effect of blue light against malodour-producing bacteria in an experimental oral biofilm.

Oral malodour is thought to be caused mainly by the production of volatile sulfide compounds (VSCs) by anaerobic Gram-negative oral bacteria. Previous studies have shown that these bacteria are susceptible to blue light (400-500 nm wavelength). In the present study, we tested the effect of blue light in the presence of zinc, erythrosine B or both on malodour production in an experimental oral biofilm. Biofilms were exposed to a plasma-arc light source for 30, 60 and 120 s (equal to energy fluxes of 41, 82 and 164 J cm(-2), respectively) with or without the addition of zinc acetate, erythrosine B or both. After the light exposure, biofilm samples were examined for malodour production (by an odour judge) and VSC production (with a Halimeter), and VSC-producing bacteria were quantified using a microscopy-based sulfide assay (MSA) and in situ confocal laser scanning microscopy (CLSM). Results showed that exposing experimental oral biofilm to both blue light and zinc reduced malodour production, which coincided with a reduction in VSC-producing bacteria in the biofilm. These results suggest that zinc enhances the phototoxicity of blue light against malodour-producing bacteria.

Efficacy of three hygienic protocols in reducing biofilm adherence to removable thermoplastic appliance.

OBJECTIVES: To examine the ability of a removable thermoplastic appliance (RTA) to adsorb hygienic solutions and inhibit bacterial growth and to examine the efficacy of three hygiene protocols in reducing bacterial biofilm adherence to RTA. MATERIALS AND METHODS: Solution adsorption and bacterial growth inhibition were examined in vitro using paper vs RTA discs. Subsequently, 11 patients treated with RTA (mean age, 29.1 ± 4.7 years) were assigned into a sequence of three hygiene protocols: regular RTA brushing (baseline), immersion RTAs in chlorhexidine mouthwash (CHX), and using a vibrating bath with cleaning solution (VBC). For each patient, 12 upper RTAs were examined (2 baseline RTAs, 5 CHX RTAs, and 5 VBC RTAs), for a total of 132 RTAs. All RTAs were stained with gentian violet, and biofilm presence was measured using a photodensitometer. RESULTS: The RTA discs did not adsorb CHX or cleaning solution. The later agent did not show antibacterial features. Baseline RTAs showed significant biofilm adherence (P < .001) on the posterior palatal side of the aligner and on the anterior incisal edge. CHX and VBC hygienic protocols significantly (P < .001) reduced baseline biofilm adherence by 16% and 50%, respectively. Hygienic improvement was maintained over 140 days when CHX and VBC were used. However, VBC was three times more efficient than CHX. CONCLUSIONS: This study highly recommends the use of a VBC protocol. Biofilm deposits on the RTA, especially on incisal edges and attachment dimples, could lead to inadequate tooth/RTA and attachment/RTA overlap and consequently impair tooth alignment.

Salivary Candida, caries and Candida in toothbrushes.

BACKGROUND: Candida species are common inhabitants of the normal oral microbiota. A few studies founded a relationship between high levels of Candida albicans in the oral cavity and high DMF scores. Toothbrushes can also be reservoirs of microorganisms, the proliferation of these microorganism on a toothbrush could be a major factor for its distribution in the oral cavity. AIM: To examine the associations between salivary Candida and DMF, and between salivary Candida and Candida in the toothbrush. METHOD: 46 healthy school children, who attended a University pediatric dental clinic, were tested for Candida in their saliva and in their toothbrush. Their DMF was recorded. RESULTS: 38 children were Candida-positive (79.2%), out of whom 5 demonstrated a positive growth of Candida in the toothbrushes. No correlation was found between Candida in the saliva and in the toothbrush. The number of Candida-positive girls was significantly higher than the number in boys. No significant relationship between caries experience and the presence of Candida was found CONCLUSIONS: No correlation was found between Candida in the saliva and in the toothbrush. The origin of the Candida in the toothbrush is not totally clear.

Interaction of chlorhexidine with smooth and rough types of titanium surfaces.

BACKGROUND: Chlorhexidine (CHX) digluconate exerts plaque inhibitory efficacy in the natural dentition environment due to a superior degree of persistence at the tooth surface. The purpose of the present study was to assess the interaction of CHX with titanium surfaces to estimate its antiplaque potential in the peri-implant environment. METHODS: Saliva-coated machined smooth (S) and sand-blasted acid-etched rough (R) titanium disks were soaked in either 0.1% or 0.2% CHX solution. After 24 hours, CHX amounts that were adsorbed, washed out, and desorbed from the titanium surfaces were determined spectrophotometrically at 230 nm. The antibacterial activity of CHX-treated titanium disks was assessed by measuring bacterial inhibition zones on Streptococcus mutans lawns. RESULTS: Titanium disks adsorbed 3% to 8% of the available CHX, which was significantly higher with 0.2% CHX (P<0.001) than with 0.1% CHX and two-fold higher on the R titanium disks compared to S titanium surface (P<0.001). After rinsing with water, 2.2% of the adsorbed CHX was washed out. Over 24 hours, S- and R-type disks released 1.1% and 0.6% of the adsorbed agent, respectively. Larger bacterial inhibition zones were obtained with 0.2% CHX and in R disks compared to S disks. CONCLUSIONS: CHX displayed persistence at the titanium surface. The adsorption level and bacterial growth inhibition were affected by CHX concentration and titanium surface characteristics, with higher levels of adsorption and antibacterial activity with 0.2% CHX and rough titanium surface. The slow CHX release rate suggests persistence of this agent at the titanium-pellicle surface, which can provide a long-term antiplaque effect.