Antibacterial effect of coffee: calcium concentration in a culture containing teeth/biofilm exposed to Coffea Canephora aqueous extract.

UNLABELLED: This study determined the changes of calcium concentration in a medium containing teeth/biofilm exposed to Coffea canephora extract (CCE). Enamel fragments were randomly fixed into two 24-well polystyrene plates containing BHI. Pooled human saliva was added to form biofilm on fragments. Specimens were divided into treatment groups (G, n = 8 per group) and treated with 50 µl daily for 1 min per week, as follows: G1, 20% CCE; G2, Milli-Q water (negative control); G3, antibiotic (positive control). Six fragments represented the blank control (G4). The calcium content was observed at baseline, 4 and 7 days of treatment by atomic-absorption spectrophotometry. Cross-sectional hardness of enamel was a demineralization indicator. Calcium increased in the medium after 4 and 7 days of treatment in G1 (3·80 ± 1·3 mg l(-1) and 4·93 ± 2·1 mg l(-1) , respectively) and G3 (4th day = 5·7 ± 1·8 mg l(-1) ; 7th day = 6·7 ± 3·5 mg l(-1) ) (P > 0·05). Calcium from G2 decreased after 7 days, which was different from G3 (P < 0·05). The lower calcium content, at the end of the experiment, was represented by G4, 2·16 ± 0·2 mg l(-1) . The increase in calcium after treatment with CCE is probably due to its antibacterial effect, which caused the bacterial lysis and consequent release of calcium in the medium. SIGNIFICANCE AND IMPACT OF THE STUDY: This study revealed an inhibitory action of Coffea canephora against dental biofilm. This coffee species caused bacterial lysis and consequent release of calcium into the medium. Furthermore, the advantage of coffee as an antibacterial beverage is that it is consumed in a concentrated form (6-10%) as opposed to various medicinal infusions that have shown such effect in vitro and are usually consumed at 1-2%. Therefore, a light roasted C. canephora aqueous extract can be considered as a potential anticariogenic substance.

Cross-sectional microhardness of bovine enamel subjected to three paediatric liquid oral medicines: an in vitro study.

AIM: This study aimed to investigate the in vitro effects of three paediatric liquid oral medicines on bovine dental enamel subsurfaces under pH cycling conditions. METHODS: Bovine enamel blocks were evaluated for surface hardness at baseline for sample selection. 52 intact bovine enamel blocks (16mm(2)) were randomly divided into four groups (n=13) according to the immersion treatments: G1: antibiotic (Klaricid®), G2: antihistamine (Claritin®), G3: antihistamine (Dimetapp®) and G4: control (de-ionised water). The blocks were submitted to pH cycling treatments twice a day for 12 days. The medicines were evaluated for pH, viscosity, and concentration of calcium, phosphate and fluoride. After the treatment period, cross-sectional microhardness (CSMH) measurements of the enamel blocks were taken and the data, expressed in Knoop hardness number (kg/mm(2)) was used to calculate the ΔS. STATISTICS: ANOVA followed by the Tukey test were used for statistical analyses (p<0.05). RESULTS: The antibiotic Klaricid® showed the highest concentration of fluoride, calcium and phosphate. Considering pH and viscosity, the following pattern was observed according to the treatment group: G4>G1>G2>G3 and G1>G2>G3>G4 respectively. Regarding the demineralisation pattern, the following results were observed: G4>G3>G2>G1. Compared to the control, the antibiotic and both the antihistamines provoked less demineralisation of the enamel blocks (p<0.05). CONCLUSIONS: Antibiotic G1 (Klaricid®) presented an in vitro protective effect against acid attacks probably due to its mineral content and viscosity.

Inhibitory properties of Coffea canephora extract against oral bacteria and its effect on demineralisation of deciduous teeth.

OBJECTIVES: The antibacterial activity of Coffea canephora extract was evaluated in vitro against Streptococcus mutans and Streptococcus sobrinus. The viability of planktonic cells was analysed by susceptibility tests (MIC and MBC) and time-kill assays. The effect of the extract on dental demineralisation was also investigated. METHODS: Primary 1st molar fragments (n=24) were inoculated with a saliva pool and sustained in a multiple plaque growth system for 10 days to form biofilm. The biofilm was treated with light roasted C. canephora extract at 20%, Milli-Q water (negative control) and chlorhexidine (positive control) once a day, during a week. Blank controls comprised fragments without treatment. Biofilm pH was monitored in the last day of treatment. Changes in tooth mineralisation were assessed by cross-sectional microhardness (CSMH) test. RESULTS: MIC and MBC for S. mutans were 7±2 mg/mL and 160±0 mg/mL, respectively, showing no activity for S. sobrinus. The extract produced a 4-log reduction in the number of colonies of S. mutans after 3-h treatment (p<0.05) with undiluted extract (20%) and MBC concentration (16%). There was no difference among negative/blank controls and coffee plaque pH. Differences between CSMH values of dental fragments subjected to the coffee extract and to chlorhexidine were not significant. At depths up to 30 µm from the enamel surface, coffee extract and chlorhexidine promoted higher CSMH values when compared to blank/negative controls (p<0.05). CONCLUSION: Our data suggest that light roasted C. canephora extract is beneficial as an anticariogenic substance.

Reliability of two methods for measurement of alveolar bone level in children.

OBJECTIVES: To determine the intra- and interexaminer reliability of two methods (calliper and computerized images) for measuring the alveolar bone level on bitewing radiographs of pre-school children and to determine the extent to which one method can measure more sites. METHODS: Standardized paediatric bitewings were analysed with either an image analysis program (ImageTool) or a digital calliper (Digimatic Caliper). With each method, radiographs were measured three times by three trained examiners. The differences in the number of sites measured with the two methods were assessed with McNemar's tests and kappa statistics. Reliability was assessed with paired t-tests, intraclass correlation coefficients (ICCs), Bland-Altman and survival-agreement plots. RESULTS: The kappa statistics and McNemar's test indicated that examiners measured 14% fewer sites using ImageTool. Paired t-tests also demonstrated a statistically significant bias (range 0.11-0.23 mm) indicating larger measurements for this method, although these observed differences were considered clinically unimportant for the detection of 2 mm of bone loss (which was considered the threshold for periodontal disease). Intra- and interexaminer reliability (ICC range: 0.87-0.97) was considered good for both methods. CONCLUSIONS: Reliable methods to assess alveolar bone loss in primary teeth are important for the diagnosis of incipient periodontal diseases. Both studied methods proved to be reliable. With the Digimatic Caliper, however, more sites were measured.