Microhardness evaluation of enamel adjacent to an improved GIC sealant after different enamel pre-treatment procedures.

AIM: This in vitro study was carried out to evaluate the microhardness of enamel adjacent to a glass ionomer cement (GIC) with high fluoride content used as a sealant (Fuji Triage, GC Corp., Japan) after laser, bur or air abrasion treatment procedures. STUDY DESIGN: 200 freshly extracted non-carious human molars were divided into 10 experimental groups according to the enamel pre-treatment method: A air abrasion (Mach 4.1 Kreativ Inc., USA); AP, Air abrasion + conditioning with 20% polyacrylic acid (GC cavity conditioner); L, Er,Cr:YSGG laser application (Waterlase, Biolase Technology, Inc., San Clemente, USA); LP, Er,Cr:YSGG laser application and fissure conditioning; B, ameloplasty carried out with a diamond bur especially designed for preparing fissures (Komet #8833); BP, ameloplasty + fissure conditioning; P, application of 20% polyacrylic acid and all fissures sealed with GIC; C, no fissure treatment, the material was applied directly to the fissures (control); R, application of 37% orthophosphoric acid and fissures sealed with a resin-based sealant (Fissurit; Voco, Germany) (control); N, no treatment (control). Half of each group of teeth were left in artificial saliva for one month and the rest for three months. The teeth were then sectioned and microhardness was measured using a Vickers test apparatus. Kruskal-Wallis, Mann-Whitney U and Dunn's multiple comparison tests were carried out (5% significance). RESULTS: After one month results regarding hardness at the base and lateral walls of fissures were significantly higher in groups A, AP, L, LP, B, BP, P and C than in groups R and N (p<0.01), but no difference was seen between the treatment procedures. The results after three months produced similar findings with evenly increased values for all groups. CONCLUSION: The results of this study showed that the tested GIC with a higher fluoride content seemed to improve the enamel hardness of the fissure enamel and could be regarded as an alternative material in cases where resin sealant applications are questionable.

Fluoride in dental plaque after a single toothbrushing with monofluorophosphate dentifrice.

Many studies have shown that topical fluoride applications can produce a fluoride reservoir in dental plaque. Since the most common topical fluoride application is via toothbrushing with fluoridated dentifrices, the aim of this study was to measure fluoride uptake by dental plaque after a single toothbrushing with monofluorophosphate (MFP) toothpaste and to follow the plaque until its fluoride concentration returned to the prebrushing levels. In a fluoridated area, plaque samples were collected from 26 children who brushed with MFP toothpaste, 22 children who brushed with a fluoride-free control toothpaste, before brushing and at intervals of 10 minutes, 1 hour and 2 hours after brushing. A combination fluoride electrode was used to determine the fluoride content of the samples. In conclusion, our study has shown that brushing with fluoridated water has a positive effect on the fluoride level of the plaque and the addition of MFP did not make a significant change, although it had a short term effect. A negative correlation was established between plaque wet weight and its fluoride content whenever the plaque equilibrated.