Resin-modified glass ionomer cement and a resin-based material as occlusal sealants: a longitudinal clinical performance

PURPOSE

The aim of this study was to compare retention, effectiveness in caries prevention and superficial characteristics in 2 different materials used as an occlusal sealant.

METHODS

The sample consisted of 108 school children with a mean age of 7.5+/-1.25 years, in which 364 first permanent molars were divided into 6 groups: (1) group 1=Delton + rubber dam (used only for this group); (2) group 2=Delton + cotton rolls; (3) group 3=Prime & Bond 2.1 + Delton; (4) group 4=Vitremer with a 0.25:1 powder/liquid proportion; (5) group 5=Primer + Vitremer with a 0.25:1 powder/liquid proportion; and (6) group 6=Vitremer with a 1:1 powder/liquid proportion.

RESULTS

After 12 months, the total retention rate for groups 6, 1, 2, 3, 4, and 5 was, respectively: 92%, 79%, 67%, 52%, 41% and 12%. For the 3 occlusal areas, retention was: 97%, 92%, 86%, 77%, 69%, and 36%. For the modified criterion, the proportion test showed a statistically significant difference (P<.05) between: groups 1 and 4; groups 6 and 2; and group 3, 4, and 5 with all others groups. Considering the total of 3 areas, there was a statistically significant difference (P<.05) between: groups 1 and 6 with groups 3 and 4; group 2 with group 4; and groups 6 and 5 with the others.

CONCLUSION

The resin-modified glass ionomer cement may be a promising alternative as an occlusal sealant.

Effect of iron on bovine enamel and on the composition of the dental biofilm formed “in situ”

OBJECTIVES

This study investigated in situ the effect of iron (Fe) on the reduction of demineralization of bovine enamel, as well as on the composition of dental biofilm.

DESIGN AND METHODS

Twelve volunteers were included in this blind crossover study, which was conducted in two stages of 14 days each. For each stage, the volunteers received palatal appliances containing four blocks of bovine enamel (4 mm x4 mm x 2.5 mm). Six volunteers dripped a solution of 15 mmol L(-1) ferrous sulphate onto the fragments and the remaining six dripped deionized water (eight times per day). After five minutes, a fresh 20% (w/v) sucrose solution was dripped onto all enamel blocks. During the experimental period the volunteers brushed their teeth with non-fluoridated dentifrice. After each stage, the percentage of surface microhardness change (%SMHC) and area of mineral loss (DeltaZ) were determined on enamel and the dental biofilm formed on the blocks was collected and analysed for F, P, Ca, Fe and alkali-soluble carbohydrates. The concentrations of F, Ca and Fe in enamel were also analysed after acid biopsies.

RESULTS

There was a statistically significant increase in the P and Fe concentrations in the biofilms treated with ferrous sulphate (p<0.05), which was not observed for F, Ca and alkali-soluble carbohydrates. The group treated with ferrous sulphate had significantly lower %SMHC and DeltaZ when compared to control (p<0.05).

CONCLUSIONS

These results showed that ferrous sulphate reduced the demineralization of enamel blocks and altered the ionic composition of the dental biofilm formed in situ.

Fluoride kinetics in saliva after the use of a fluoride-containing chewing gum

There is a relationship between the use of fluoride, the reduction of dental caries and the increase of dental fluorosis. The purpose of this study was to analyze the fluoride kinetics in saliva after using the HappydentTM chewing gum, which contains 3.38 mg of fluoride as monofluorophosphate. Fifteen 7-9-year-old volunteers were instructed to chew the gum TridentTM (control) and HappydentTM on different days. Total saliva was collected for 3 minutes, at 0, 3, 6, 9, 15, 30 and 45 minutes after starting chewing. Salivary fluoride was analyzed with a fluoride-specific electrode (Orion 96-09) after acid hydrolysis. The data were analyzed by two-way analysis of variance and by Tukey’s post hoc test (p < 0.05). The mean amounts ± sd (mg) of fluoride released in saliva were 0.276 ± 0.126 and 0.024 ± 0.014 for HappydentTM and TridentTM respectively. The fluoride amount in the saliva samples after the use of Happydent was significantly higher than after the use of TridentTM in all experimental periods, except after 30 and 45 minutes. The high fluoride presence in saliva after the use of Happydent may be significant to prevent dental caries and this should be evaluated in clinical researches. On the other hand, children at an age of risk for dental fluorosis should avoid the use of HappydentTM.

The influence of mouthrinses with antimicrobial solutions on the inhibition of dental plaque and on the levels of mutans streptococci in children

The effect of daily mouthrinses on dental plaque accumulation and on salivary mutans streptococci was investigated in 200 children. The utilized solutions were: a placebo solution composed of mentholated deionized water (group I); 0.12% chlorhexidine gluconate associated to 0.05% sodium fluoride (group II); 0.2% chlorhexidine digluconate (group III), and 0.5% stevioside mixed with 0.05% sodium fluoride, with pH 3.4 (group IV). In order to verify the effect on plaque formation, the accumulation of plaque was assessed by means of the Löe12 index, at the beginning and at the end of the experiment, whereas the quantification of cariogenic streptococci was accomplished on three saliva samples collected at 3 different moments: before the first mouthrinse, 24 hours after the first mouthrinse and 1 week after the last mouthrinse. The mouthrinsing routine was carried out on a daily basis during 4 weeks. Five milliliters of solution were rinsed during 1 minute. The results revealed 4.10, 26.75, 41.20, and 5.91% of reduction in plaque accumulation for groups I, II, III, and IV, respectively. Comparisons between the groups as to plaque reduction revealed that groups II and III were significantly different from groups I (control) and IV (p < 0.05), but did not differ from each other. The solution utilized by group III was the least accepted by children and, as the solution utilized by group II, caused mild dental pigmentation. There were no statistically significant differences as to the levels of mutans streptococci, probably due to the low initial levels observed in each one of the four groups.