Replacing amalgam with a high-viscosity glass-ionomer in restoring primary teeth: A cost-effectiveness study in Brasilia, Brazil.

OBJECTIVES: When planning primary oral health care services the cost implications of adopting new intervention practices are important, especially in resource-strapped countries. Although on a trajectory to be phased-out, amalgam remains the standard of care in many countries. METHODS: Adopting a government perspective, this study compared the costs of performing amalgam and ART/high-viscosity glass-ionomer cement (HVGIC) restorations and the consequences of failed restorations over 3 years in suburban Brasilia, Brazil. Cost data were collected prospectively; cost estimates were developed for the study sample and a projection of 1000 single- and 1000 multiple-surface restorations per group. Probabilistic sensitivity analysis was conducted in TreeAge Pro. RESULTS: Results were mixed. For single-surface restorations, ART/HVGIC will cost US$51 per failure prevented, while for multiple-surface restorations, ART/HVGIC was cost-effective with a savings of US$11 compared to amalgam. Probabilistic sensitivity analysis (Monte Carlo simulation) predicted amalgam would be cost-effective 49.2% of the time compared to HVGIC at 50.6% of the time at a willingness to pay threshold of US$237 per failure prevented. Personnel accounted for more than half the cost burden for both methods; instruments and supplies accounted for about one third. The per restoration cost to replace amalgam with HVGIC ranges from US$1 to a savings of US$0.84. CONCLUSION: Replacing amalgam with a high-viscosity glass-ionomer as part of the ART method comes at a minimal increase in cost for governments. Increasing the number of restorations seems to diminish the cost burden. CLINICAL SIGNIFICANCE: ART/HVGIC could be considered a viable alternative to amalgam in primary teeth.

Análise de custo-efetividade de métodos preventivos para superfície oclusal de acordo com o risco de cárie: resultados de um ensaio clínico controlado / Cost-effectiveness analysis of preventive methods for occlusal surface according to caries risk: results of a controlled clinical trial / Análisis del coste-efectividad de los métodos preventivos para una superficie oclusal según el riesgo de caries: resultados de un ensayo clínico controlado

Este estudo apresenta o resultado de uma avaliação de custo-efetividade conduzida ao longo de um ensaio clínico controlado para avaliar a efetividade do selamento com ionômero de vidro modificado por resina (Vitremer, 3M ESPE) e da aplicação de verniz fluoretado (Duraphat, Col-gate) em superfícies oclusais de primeiros molares permanentes, em crianças de 6 a 8 anos (N = 268), segundo o risco de cárie (alto risco; baixo risco). As crianças foram examinadas semestralmente, ao longo de 24 meses, pelo mesmo dentista calibrado, após alocação em seis grupos: controle alto risco e baixo risco (educação em saúde bucal trimestral); verniz alto risco e baixo risco (educação em saúde bucal trimestral + aplicação semestral de verniz); e selante alto risco e baixo risco (educação em saúde bucal trimestral + única aplicação do selante). A análise mostrou que o selamento de primeiros molares permanentes em crianças de alto risco apresentou razão de C/E de R$ 225,21(US$ 119,80) por superfície oclusal salva, e razão incremental de C/E de R$ 203,71(US$ 108,36) por superfície oclusal adicional salva. Conclui-se que uma única aplicação de selante, em escolares de alto risco, foi a intervenção mais custo-efetiva.

This study presents the results of a cost-effectiveness analysis in a controlled clinical trial on the effectiveness of a modified glass ionomer resin sealant ( Vitremer, 3M ESPE) and the application of fluoride varnish (Duraphat, Colgate) on occlusal surfaces of first permanent molars in children 6-8 years of age (N = 268), according to caries risk (high versus low). Children were examined semiannually by the same calibrated dentist for 24 months after allocation in six groups: high and low risk controls (oral health education every three months); high and low risk with varnish (oral health education every three months + varnish biannually); and high and low risk with sealant (oral health education every three months + a single application of sealant). Economic analysis showed that sealing permanent first molars of high-risk schoolchildren showed a C/E ratio of US$ 119.80 per saved occlusal surface and an incremental C/E ratio of US$ 108.36 per additional saved occlusal surface. The study concluded that sealing permanent first molars of high-risk schoolchildren was the most cost-effective intervention.

En este estudio se presentan los resultados de una evaluación de costo-efectividad (C/E) durante un ensayo clínico controlado para evaluar la efectividad de la obturación con ionómero de vidrio modificado con resina (Vitremer, 3M ESPE) y la aplicación de barniz de flúor (Duraphat, Colgate) en las superficies oclusales de los primeros molares permanentes, para niños de 6-8 años (N = 268) de edad, de acuerdo con el riesgo de caries (alto riesgo-bajo riesgo). Los niños fueron examinados cada seis meses por el mismo dentista calibrado, durante 24 meses, después de haberle sido asignados seis grupos: control alto riesgo y bajo riesgo (educación de salud bucal cada tres meses); barniz alto riesgo y bajo riesgo (educación de salud bucal cada tres meses + barniz semestralmente); obturación alto riesgo y bajo riesgo (educación de salud bucal cada tres meses + una sola aplicación de ionómero de vidrio). El análisis económico mostró que la obturación de los primeros molares permanentes de escolares de alto riesgo presenta una relación C/E de US$ 119.80 de ahorro por superficie oclusal y una ratio C/E incremental de US$ 108.36 de ahorro adicional por superficie oclusal.

[Cost-effectiveness analysis of preventive methods for occlusal surface according to caries risk: results of a controlled clinical trial]. / Análise de custo-efetividade de métodos preventivos para superfície oclusal de acordo com o risco de cárie: resultados de um ensaio clínico controlado.

This study presents the results of a cost-effectiveness analysis in a controlled clinical trial on the effectiveness of a modified glass ionomer resin sealant ( Vitremer, 3M ESPE) and the application of fluoride varnish (Duraphat, Colgate) on occlusal surfaces of first permanent molars in children 6-8 years of age (N = 268), according to caries risk (high versus low). Children were examined semiannually by the same calibrated dentist for 24 months after allocation in six groups: high and low risk controls (oral health education every three months); high and low risk with varnish (oral health education every three months + varnish biannually); and high and low risk with sealant (oral health education every three months + a single application of sealant). Economic analysis showed that sealing permanent first molars of high-risk schoolchildren showed a C/E ratio of US$ 119.80 per saved occlusal surface and an incremental C/E ratio of US$ 108.36 per additional saved occlusal surface. The study concluded that sealing permanent first molars of high-risk schoolchildren was the most cost-effective intervention.

In vitro assessment of the effectiveness of whitening dentifrices for the removal of extrinsic tooth stains.

This in vitro study evaluated the effectiveness of whitening dentifrices for the removal of extrinsic tooth stains. Twenty dental blocks (4 x 4 mm), including enamel and dentine, removed from freshly extracted bovine incisors, were randomly divided into 4 groups: G1--distilled water, G2--Colgate, G3--Crest Extra Whitening and G4--Rapid White. In all specimens, the dentin was covered with colorless nail polish, and the enamel was left exposed. Next, the specimens were immersed in a solution of black tea, which was changed every 24 h, for a period of 6 days. After this period, a photo-reflectance reading was taken (Time 1) with a spectrometer. The stained specimens were then submitted to linear brushing movements (5,000 cycles) using brushes (Oral B-Soft) coupled to an automatic toothbrushing machine, under a static axial load of 200 g and with a speed of 4 movements/second, at 37 degrees C, with the dentifrice or water being injected every 60 s. When toothbrushing ended, a second photo-reflectance reading was taken (Time 2). The results were submitted to two-criteria analysis of variance (ANOVA) and to the Tukey test ( = 0.05). When the two times for a same group were compared, Time 2 presented the highest reflectance values with statistical difference only for G3 and G4. Among the dentifrices tested, only the Rapid White group differed from the control group, presenting the highest reflectance values. Only the whitening dentifrice Rapid White was effective for the removal of extrinsic stains.

In vitro assessment of the effectiveness of whitening dentifrices for the removal of extrinsic tooth stains

This in vitro study evaluated the effectiveness of whitening dentifrices for the removal of extrinsic tooth stains. Twenty dental blocks (4 x 4 mm), including enamel and dentine, removed from freshly extracted bovine incisors, were randomly divided into 4 groups: G1 - distilled water, G2 - Colgate, G3 - Crest Extra Whitening and G4 - Rapid White. In all specimens, the dentin was covered with colorless nail polish, and the enamel was left exposed. Next, the specimens were immersed in a solution of black tea, which was changed every 24 h, for a period of 6 days. After this period, a photo-reflectance reading was taken (Time 1) with a spectrometer. The stained specimens were then submitted to linear brushing movements (5,000 cycles) using brushes (Oral B-Soft) coupled to an automatic toothbrushing machine, under a static axial load of 200 g and with a speed of 4 movements/second, at 37°C, with the dentifrice or water being injected every 60 s. When toothbrushing ended, a second photo-reflectance reading was taken (Time 2). The results were submitted to two-criteria analysis of variance (ANOVA) and to the Tukey test ( = 0.05). When the two times for a same group were compared, Time 2 presented the highest reflectance values with statistical difference only for G3 and G4. Among the dentifrices tested, only the Rapid White group differed from the control group, presenting the highest reflectance values. Only the whitening dentifrice Rapid White was effective for the removal of extrinsic stains.

Model for assessment of carious lesion remineralization, and remineralization by a novel toothpaste.

This study is of a novel toothpaste which induced remineralization of carious lesions in specific pathogen-free Osborne-Mendel rats. Randomly distributed weanlings in 7 groups (n = 10) each were initially induced to develop carious lesions as a result of a severe dietary and bacteriological challenge. Thus, all were inoculated with S. mutans 10449S, ate diet 2000CS (containing 56% cornstarch) ad libitum, and, upon weaning and for 10 additional days, drank demineralized water supplemented to 10% (w/v) with sucrose (SW) ad libitum. During these 10 days, 6 of the 7 groups of rats were topically treated with a slurried F(-)-free placebo toothpaste. On the 10th day after initial inoculation, two groups were sacrificed, one which had been treated with the placebo and the one which had been untreated. The remaining groups were then provided unsupplemented demineralized water (DW), fed diet 2000CS, and topically treated with either of 5 coded toothpastes: a slurry of the F(-)-free placebo, a similar slurry of a conventional sodium fluoride toothpaste (Crest Regular) containing about 383 ppm F-, or one of three prototype toothpastes formulated by Enamelon, Inc. containing soluble calcium and phosphate salts. Two of these contained 377 ppm F- after mixing their components, either as sodium monofluorophosphate (E-MFP) or as NaF (E-NaF). The third prototype contained 0 ppm F- (E-w/o F). Test items were applied to the dentition for one minute/day, five days/week. These 5 remaining groups were sacrificed 13 days after the DW provision. After defleshing, heads were coded randomly and scored blindly for carious lesions. The exchange of DW for SW was associated with highly significant reductions of 10449S recoveries (p < 0.001), but there were no differences in recoveries among the groups as a function of toothpaste type. Total mandibular and maxillary sulcal and smooth surface caries scores were statistically significantly lower for the E-NaF-treated group at 23 days than for the 23-day placebo-, E-w/o F(-)-, and conventional NaF toothpaste-treated group. Reductions were most impressive quantitatively on approximal tooth surfaces, where both the E-MFP and E-NaF groups had the lowest scores, but were also statistically significant at sulcal surfaces for the E-NaF group. Thus, this study model can be used to detect significant remineralization effects, as occurred with the prototype toothpaste E-NaF.

An in vitro assessment and a pilot clinical study of electrical resistance of demineralized enamel.

Electrical resistance measurement was evaluated in vitro and in vivo as a method for comparing the remineralizing performance of toothpastes. In the in vitro study, areas of sound enamel on 12 unrestored, mature, extracted human molars and bicuspids, with electrical resistance readings greater than 99.99 M omega, were demineralized to an electrical resistance of 1 to 4 M omega. The teeth were divided into three groups. The change in electrical resistance was measured following a 15 cycle regimen of treatment, demineralization and salivary soaking. Treatments were five-minute exposures to either a 1:2 slurry in saliva of Enamelon (E), a remineralizing fluoride-toothpaste also containing soluble calcium and phosphate ions, a 1:2 slurry in saliva of Crest (C), a conventional fluoride toothpaste (P), or to saliva alone. Demineralization was performed with a 30-minute exposure to 0.1 M lactic acid 50% saturated with calcium hydroxyapatite. The salivary soaking was 1 hour in duration. The mean electrical resistance of the E, C and the saliva treated sites was 63.9 +/- 4.3, 37.6 +/- 9.5 and 2.1 +/- 0.7 M omega, respectively. The final resistance was statistically different for each group (p < 0.05). A pilot clinical study was then conducted to assess the electrical resistance technology in vivo. Eighteen adult subjects with at least one site of early enamel caries with an electrical resistance between 1.0 M omega and 20.00 M omega were randomly assigned to either Enamelon, Crest, or a non-fluoride placebo toothpaste and asked to brush twice daily. After three months, the mean resistance of the test sites was 23.57 M omega for E, 9.61 M omega for C and 13.24 M omega for P. However, the mean resistance changes did not proceed consistently over time. At the end of the study, the electrical resistance measurements on four sites out of twelve in Group E were suggestive of remineralization, whereas measurements on one site out of ten were suggestive of remineralization in Group C and two or three sites out of twelve were suggestive of remineralization in Group P. Progression of demineralization was possibly indicated in only one site, which was in Group C. There were insufficient subjects for statistical significance in the pilot clinical study. There were apparent problems with the variability of some measurements between visits in the in vivo study. Overall, however, the results of both studies indicate that with modifications to the equipment, electrical resistance measurements may be a means of comparing the remineralization performance of toothpastes.

Laboratory assessment of tooth whitening by sodium bicarbonate dentifrices.

The increasing emphasis on dental aesthetics has made tooth whitening an important function of a dentifrice. This laboratory study investigated the whitening effect of toothbrushing with sodium bicarbonate-based dentifrices compared with standard dentifrices that do not contain sodium bicarbonate. Six dentifrices and a distilled water control were tested for their ability to whiten teeth with intrinsic stain. The dentifrices contained different abrasive systems: (1) 45% NaHCO3; (2) 65% NaHCO3 (Arm and Hammer Dental Care); (3) 94% NaHCO3; (4) 94% NaHCO3 + 1.5% H2O2; (5) silica (Crest Regular Toothpaste); and (6) dicalcium phosphate (Colgate Regular Toothpaste). After a thorough rubber cup cleaning with a pumice slurry, the intrinsic color of the test teeth with a Vita shade of A3 or darker was measured with a spectrophotometer using the standard L*a*b* color scale. Measurements were taken on a total of 12 teeth per test dentifrice before treatment, and after 30, 60, 90 and 120 minutes of mechanical toothbrushing. No changes in L* (lightness/brightness) or a* (red-green hue) occurred, but significant differences in b* (yellow-blue hue) were observed over time. Compared to baseline tooth color, all four sodium bicarbonate-based dentifrices were significantly effective in removing the yellow intrinsic tooth stain, while the water control, silica dentifrice, and dicalcium phosphate dentifrice demonstrated no significant change. Between-group comparisons showed that the four dentifrices containing sodium bicarbonate were significantly more effective than the water and dicalcium phosphate dentifrice groups. The commercial dentifrice containing 65% sodium bicarbonate was also more effective than the commercial silica dentifrice. Although continued toothbrushing from 30 to 120 minutes resulted in additional stain removal, most of the tooth whitening by the sodium bicarbonate-based dentifrices occurred in the first 30 minutes of brushing. In the studies conducted, dentifrices containing high concentrations of sodium bicarbonate were more effective at removing intrinsic tooth stain than dentifrices that do not contain sodium bicarbonate.

Quantitative assessment of the efficacy of amorphous calcium phosphate/methacrylate composites in remineralizing caries-like lesions artificially produced in bovine enamel.

Recent studies show that methacrylate-based composites with amorphous calcium phosphate (ACP) as a filler can release supersaturating levels of calcium and phosphate ions in proportions favorable for apatite formation. These findings suggest that such composites could be effectively used as coatings for remineralizing teeth damaged by tooth decay. To examine this hypothesis, we tested composites in vitro for their efficacy to remineralize artificially formed caries-like lesions in extracted bovine incisors. Single 120-microns-thick sagittal tooth sections were placed in holders that exposed only the carious enamel surface. The exposed surfaces were coated with a 1-mm- to 1.5-mm-thick layer of the composite containing, by mass, 40% apatite, silica, or P2O7(-4)-stabilized ACP and 60% photoactivated resin comprised of Bis-GMA, TEGDMA, HEMA, and ZrM. The photocured composite-coated sections were immersed either in a remineralizing solution for 4 weeks at 37 degrees C (static model) or cyclically immersed in demineralizing (0.5 h) and remineralizing solutions (11.5 h) for 2 weeks (dynamic model). Quantitative digital image analysis of matched 102 microns x 220 microns areas from contact microradiographs taken of the sections before and after immersion showed that lesions coated with ACP-filled composites fractionally recovered 71% +/- 33% of their lost mineral compared with 14% +/- 13% for apatite controls in the static model and 38% +/- 16% compared with -6% +/- 24% in the dynamic model. The results suggest that sealants based on ACP-filled methacrylate composites have the potential to remineralize carious enamel lesions.