In situ transformation of glass-ionomer into an enamel-like material.
ABSTRACT To assess the nature of clinically detectable alterations in glass-ionomer after long-term clinical service.
In addition to clinical macro pictures, SEM was carried out on replicas and on two sectioned primary molars SEM-EDAX analysis was performed to determine chemical transformation in the glass-ionomer. Also with SEM-EDAX, the composition was determined of a partially removed half-year old sealant.
The clinically observed altered optical aspect and increased hardness could be related with surface structure changes as identified by SEM. The changed glass-ionomer showed a continuous integration with the adjacent enamel. The SEM-EDAX analysis revealed an increase of calcium and phosphorus in the surface layer, tentatively suggesting a sort of additional "mineralization" of the material. This phenomenon was only observed for restorations that had minimally 2-3 years in vivo dwell time.
- SourceAvailable from: José Roberto Pereira Lauris[show abstract] [hide abstract]
ABSTRACT: This study evaluated the 10-year clinical performance of high-viscosity glass-ionomer cement placed in posterior permanent teeth by means of the Atraumatic Restorative Treatment (ART) approach. One operator placed 167 single- and 107 multiple-surface restorations in 43 high-risk caries pregnant women (mean decayed teeth = 9.8 ± 5.5). Examinations were performed at 1-, 2-, and 10-year intervals according to ART criteria. In the last evaluation, the US Public Health Service (USPHS) criteria were also used. After 10 years, 129 restorations (47.1%) were evaluated and achieved a cumulative survival rate of 49.0% (SE 7.2%). The 10-year survival of single- and multiple-surface ART restorations assessed using the ART criteria were 65.2% (SE 7.3%) and 30.6% (SE 9.9%), respectively. This difference was significant (jackknife SE of difference; p < 0.05). Using the USPHS criteria, the 10-year survival of single- and multiple-surface ART restorations were 86.5% and 57.6%, respectively. The primary causes of failure were total loss (9.3%) and marginal defects (5.4%). The survival rates observed, especially for the single-surface restorations, confirm the potential of the ART approach for restoring and saving posterior permanent teeth.Clinical Oral Investigations 02/2010; 15(2):265-71. · 2.20 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: The hypotheses tested were: survival rate of fully and partially retained glass-carbomer sealants is higher than those of high-viscosity glass-ionomer, with and without energy supplied, and that of resin composite; survival rate of fully and partially retained sealants of high-viscosity glass-ionomer with energy supplied is higher than those without energy supplied. The randomized clinical trial covered 407 children, with a mean age of 8 years. The evaluation took place after 0.5, 1 and 2 years. Survival of sealant material in occlusal and in smooth surfaces, using the traditional categorization (fully and partially retained versus completely lost sealants) and the modified categorization (fully and more than 2/3 of the sealant retained versus completely lost sealants), were dependent variables. The Kaplan-Meier survival method was used. According to both categorizations of partially retained sealants, the survival of completely and partially retained resin composite sealants in occlusal and in smooth tooth surfaces was statistically significantly higher, and those of glass-carbomer sealants lower, than those of sealants of the other three groups. There was no statistically significant difference in the survival rates of completely and partially retained high-viscosity glass-ionomer sealants with and without energy supplied in occlusal and in smooth surfaces. After 2 years, glass-carbomer sealant retention was the poorest, adding energy to high-viscosity glass-ionomer sealant did not increase the retention rate and resin composite sealants were retained the longest. We suggest the use of the modified categorization of partially retained sealants in future studies. It seems not necessary to cure high-viscosity glass-ionomer sealants. The use of glass-carbomer sealants cannot be recommended yet.Clinical Oral Investigations 11/2011; 16(5):1443-50. · 2.20 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: Glass carbomer cement represents a new generation of dental material, which mineralizes gradually into fluorapatite. The aim of this study was to evaluate the microleakage and marginal integrity of newly developed glass carbomer cement with and without protective surface coating (SC) in primary molars. Standardized cavities were prepared on extracted human primary molars, and the teeth were randomly assigned into the following groups (n = 10/each): (1) conventional glass ionomer cement (GIC) without SC; (2) GIC with SC; (3) glass carbomer cement without SC; (4) glass carbomer cement with SC; and (5) compomer without SC. Following thermocycling (5 ± 2°C-55 ± 2°C, dwell time 15 s, 2000×), the specimens were immersed in 0.5% basic fuchsin solution, sectioned, and digitally photographed. Microleakage was evaluated quantitatively by using open-source image analysis toolkit (ImageJ), and the data were analyzed statistically by using Kruskal-Wallis and Conover's Multiple Comparison tests (P=.05). The greatest amount of dye leakage was observed in the uncoated glass carbomer specimens, followed by the uncoated glass ionomer group (P<.05). There was no significant difference between the microleakage values of coated glass ionomer, coated glass carbomer, and the compomer (P>.05). The following statistical ranking was observed among microleakage of the test materials: uncoated glass carbomer > uncoated glass ionomer > coated glass ionomer ≈ coated glass carbomer ≈ compomer. Uncoated glass carbomer exhibited severe internal ice crack-like lines. The use of the new glass carbomer cement without SC results in severe microleakage and catastrophic internal cracks.European journal of dentistry 01/2013; 7(1):15-21.