Effect of thickness and CAD-CAM material on fatigue resistance of endodontically treated molars restored with occlusal veneers.

PURPOSE: To evaluate the influence of the thickness and type of computer-aided design and computer-aided manufacturing (CAD-CAM) material on the fatigue resistance and failure mode of endodontically treated teeth (ETT) restored with occlusal veneers (OV). MATERIALS AND METHODS: Seventy-five (N = 75) ETT were restored with Herculite XRV in the endodontic access. Five experimental groups (n = 15) were tested. Four groups had two different thicknesses (0.6-0.7 mm or 1.4-1.6 mm) and two different CAD-CAM materials: zirconia-reinforced lithium-silicate (LS/Celtra Duo) and composite resin (RC/Cerasmart). The fifth group (control) did not have occlusal veneers. All the specimens were subjected to accelerated fatigue (5 Hz frequency) with an occlusal load increasing up to 1800 N and 131,000 cycles. The number of cycles was recorded when the machine stopped or at the completion of the test. Fatigue resistance was analyzed using the Kaplan-Meier survival test (95% significance level, log-rank post hoc pairwise comparisons). The samples were categorized according to failure mode. The CAD-CAM materials were examined through scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). RESULTS: No differences were found between the thicknesses, regardless of the type of the CAD-CAM material. The thick LS OV outperformed the RC and control groups. The thin RC OV and control groups showed a higher percentage of repairable and possibly repairable failures than the other groups. LS was more homogeneous under SEM, and the EDS analysis detected Si and Zr, but not Li. CONCLUSIONS: A larger thickness did not improve the resistance of the CAD-CAM materials. Thick LS showed a higher cumulative survival rate to fatigue than the RC and control groups. The direct composite alone (control) survived similarly to the experimental groups, except for the thick LS.

DOES TITANIUM TETRAFLUORIDE PROMOTE A PROTECTIVE EFFECT ON ERODED TOOTH? A SYSTEMATIC REVIEW AND META-ANALYSIS.

OBJECTIVE: This systematic review and meta-analyses aimed to evaluate the potential protective effect of titanium tetrafluoride (TiF4) compound compared to sodium fluoride (NaF) on eroded enamel or dentin. METHODS: Two independent reviewers searched PubMed, Scopus, Web of Science, LILACS, Cochrane, EMBASE, and Open gray Literature up to June 2020. MeSH terms, supplementary concepts, synonyms, and free terms were applied based on PICOS strategy (P- population: eroded enamel or dentin; I- intervention: eroded teeth treated with solution or varnish of TiF4; C- comparison: eroded teeth treated with a solution or varnish of NaF; O- outcome: mineral loss measurement; S- study design: in vitro studies). Seven distinct parameters evaluated the risk of bias, and all studies were submitted to 4 meta-analyses (first and second meta-analyses related to enamel loss treated with fluoride solution or varnish, respectively; third and fourth meta-analyses related to dentin loss treated with fluoride solution or varnish, respectively). A sensitivity test was performed by the RevMan software, based on standard mean difference calculation (P < .05). RESULTS: A total of 10,260 studies were retrieved, from which 22 studies were included in systematic review through eligibility criteria, of which 1 study was classified as low risk of bias, 19 as medium, and 3 as high. Seventeen studies were included in 4 different meta-analyses, presenting considerable overall heterogeneity (I2 = 95; 92; 95; and 93%, respectively) with statistical significance for TiF4 on the first meta-analysis, and no statistical significance for second, third, and fourth meta-analyses. CONCLUSIONS: Titanium tetrafluoride compound delivered as solution provided significant effective protection for erosion lesions on the enamel surface compared to sodium fluoride. However, when TiF4 or NaF were applied on enamel or dentin surfaces as varnish, both provided the same effective protection, based on in vitro studies with considerable heterogeneity.

Effect of zirconia decontamination protocols on bond strength and surface wettability.

OBJECTIVE: To evaluate the effects of human saliva decontamination protocols on bond strength of resin cement to zirconia (Y-PSZ), wettability, and microbial decontamination. MATERIALS AND METHODS: Zirconia plates were sandblasted and divided into (a) not contaminated, (b) contaminated with human saliva and: (c) not cleaned, (d) cleaned with air-water spray, (e) cleaned with 70% ethanol, (f) cleaned with Ivoclean, or (g) cleaned with nonthermal atmospheric plasma (NTAP). The wettability and microbial decontamination of the surfaces were determined after saliva contamination or cleaning. Monobond Plus (Ivoclar Vivadent) was applied after cleaning, followed by Variolink LC (Ivoclar Vivadent). The samples were stored 1 week before shear bond strength (SBS) testing, and data (SBS and wettability) were analyzed by one-way analysis of variance and Tukey test (α = .05). RESULTS: Saliva contamination reduced SBS to zirconia compared to not contaminated. Both Ivoclean and NTAP produced higher SBS compared to not cleaned and were not significantly different from the not contaminated. Ivoclean produced the highest contact angle, and NTAP the lowest. With the exception of using just water-spray, all cleaning protocols decontaminated the specimens. CONCLUSIONS: Both Ivoclean and NTAP overcame the effects of saliva contamination, producing an SBS to zirconia comparable to the positive control. CLINICAL SIGNIFICANCE: Dental ceramics should be cleaned prior to resin cementation to eliminate the effects of human saliva contamination, and Ivoclean and NTAP are considered suitable materials for this purpose.

Influence of Adhesion Promoter Primers on Polymerization Kinetics and Long-term Bond Strength of Composite Cements to Zirconia.

PURPOSE: To investigate the influence of primers on polymerization kinetics of resin-based luting and its effect on the microhardness and bond strength to zirconia. Materials and Methods: Panavia V5 (PV; Kuraray Noritake) with Tooth Primer (TPprimer; Kuraray Noritake) or Clearfil Ceramic Primer (CPprimer; Kuraray Noritake), and RelyX Ultimate (RU; 3M Oral Care) with Scotchbond Universal (SUadhesive; 3M Oral Care) were evaluated. Polymerization kinetics of luting materials with or without primers (TPprimer or SUadhesive) were evaluated using Fourier transform near-infrared (FT-NIR) spectroscopy in self- and dual-curing modes (n = 5). Microhardness of luting materials was evaluated after 1, 12, and 24 h (n = 5). Shear bond strengths to zirconia ceramics (Katana Zirconia, Kuraray Noritake; and Lava Esthetic, 3M Oral Care) after 24 h and 1 year (n = 8) were assessed to determine the effect of the following surface treatments: no treatment, non-thermal atmospheric plasma, primer (CPprimer or SUadhesive), and the combination of plasma + primers. Statistical analyses were performed at a 5% significance level. RESULTS: PV achieved a significantly higher degree of conversion (DC) when TPprimer was used, while there was no increase in conversion for RU combined with SUadhesive. Light activation significantly improved polymerization, which also produced greater microhardness. CPprimer and SUadhesive significantly improved immediate bond strength to zirconia ceramics. However, after 1 year, only SUadhesive with RU was able to maintain the bond strength. Plasma surface treatment did not improve bonding to zirconia. CONCLUSION: The use of primers improved the DC for PV only. Light curing produced higher conversion and microhardness for both resin-based luting materials. Bond strength to zirconia was improved when primers were used. However, only RU demonstrated reliable long-term adhesion to zirconia.

Adhesion of Resin Cement to Zirconia Using Argon Plasma and Primer.

PURPOSE: To evaluate the effectiveness of nonthermal atmospheric plasma (NTAP) and priming on the shear bond strength (SBS) of a resin cement to two zirconia ceramics after 24 hours and 1 year of water storage. MATERIALS AND METHODS: A total of 120 plates (9 x 7 x 2 mm) were obtained from two types of zirconia (Katana, Kuraray Noritake; and ZirCAD, Ivoclar Vivadent) plates randomly divided into 12 groups (n = 10 each). Zirconia ceramic plates were submitted to the following treatments: (1) untreated (control); (2) treated with ZPrime Plus (Bisco Dental) primer; (3) NTAP (Surface Plasma Tool Model SAP, Surface Engineering and Plasma Solution) application for 10 seconds; (4) NTAP for 30 seconds; (5) NTAP for 10 seconds followed by priming; and (6) NTAP for 30 seconds followed by priming. Two silicone molds (2.37-mm diameter x 2-mm height) were positioned on the treated surface of each zirconia plate, and the resin cement (Panavia F 2.0, Kuraray Noritake) was manipulated and inserted into the molds. After light activation, two resin cement cylinders (specimens) were obtained from each plate. One specimen was tested after 24 hours, and the other after 1 year. The shear load was applied to the base of the resin cement cylinders until failure. Data were analyzed using three-way ANOVA and post hoc Tukey test (α = .05). RESULTS: NTAP application alone (groups 3 and 4) increased SBS compared to the control group only at 24 hours. After 1 year, the NTAP/primer combination showed higher SBS than the other groups. Water storage for 1 year reduced the bond strength for all groups. CONCLUSION: NTAP, combined or not combined with primer, had a beneficial effect on adhesion after 24 hours and after 1 year. Water storage negatively influenced the adhesion in all groups.

[Dissatisfaction with dental services among dentate and edentulous elderly Brazilians: a multilevel analysis]. / Insatisfação com os serviços odontológicos entre idosos brasileiros dentados e edentados: análise multinível.

The scope of this study was to evaluate dissatisfaction with dental services among dentate and edentulous elderly Brazilians and its association with contextual and individual variables. The data from the National Oral Health Survey conducted in 2010 and contextual variables related to cities were used. Descriptive, bivariate and multilevel analysis was conducted among 1,989 elderly individuals. Of these, 11.2% of dentate and 22.1% of edentulous elderly people were dissatisfied. Among the dentate individuals, dissatisfaction was associated with contextual variables (location of municipality, human development index, GINI Index, the presence of Dental Specialty Centers and the coverage of oral health in public service) and persons related to health care and oral health conditions. For the edentulous individuals, no associated contextual variables were identified. Only the motive for the use of the service and satisfaction with teeth and mouth were associated with dissatisfaction with dental services. A considerable prevalence of dissatisfaction with the services was identified, being higher among edentulous elderly Brazilians. Among dentate elderly Brazilians, an association with contextual variables was detected.

Avaliou-se a insatisfação com os serviços odontológicos entre idosos brasileiros dentados e edentados e sua associação com variáveis contextuais e individuais. Foram utilizados os dados do Levantamento Nacional de Saúde bucal realizado em 2010 e dados contextuais referentes aos municípios. Análises descritivas, bivariadas e multinível foram realizadas. Incluiu-se 1.989 idosos. Destes, 11,2% dos idosos dentados e 22,1% dos edentados estavam insatisfeitos. Entre os dentados, a insatisfação foi associada com variáveis contextuais (localização do município, índice de desenvolvimento humano, Índice de GINI, presença de Centro de Especialidades Odontológicas e cobertura das equipes de saúde bucal) e individuais pertencentes à atenção à saúde e condições de saúde bucal. Para os idosos edentados, não foi identificado associação com variáveis contextuais. Apenas o motivo do uso do serviço e a satisfação com dentes e boca foram associados. Identificou-se uma prevalência considerável de insatisfação com os serviços, sendo maior entre os idosos edentados. Entre os idosos dentados, foi observado associação com variáveis contextuais.

Microtensile bond strength of resin cements to 3-D printed and milled temporary restorative resins / Resistencia de unión en microtracción de cementos resinosos a resinas para provisionales impresas y fresadas

Abstract To evaluate the microtensile bond strength (µTBS) of two resin cements to 3D printed and milled CAD/CAM resins used for provisional fixed partial dentures. Blocks (5 x 5 x 5 mm) of three 3D-printed resins (Cosmos3DTemp / Yller; Resilab3D Temp / Wilcos and SmartPrint BioTemp, / MMTech) were printed (Photon, Anycubic Technology Co.). A milled material (VitaCAD-Temp, VITA) was used as control. Half the specimens were sandblasted and the rest were untreated. Two blocks were bonded with the corresponding resin cement: PanaviaV5 (Kuraray Noritake) and RelyX Ultimate (3M Oral Care). After 24 hours, the bonded blocks were sectioned into 1 x 1 mm side sticks. Half the beams were tested for µTBS and the other half was thermocycled (5000 cycles, 30s dwell-time, 5s transfer time) before µTBS testing. A four way Generalized Linear Model (material*sandblasting*cement*aging) analysis was applied. VITA exhibited the lowest µTBS, regardless of the cement, sandblasting and thermocycling. Sandblasting significantly improved the µTBS of VIT, especially after aging, but did not improve the µTBS of 3D printed resins. Sandblasting was not beneficial for 3D printed resins, although is crucial for adhesive cementation of milled temporary resins. Airborne particle abrasion affects the integrity of 3D-printed resins, without producing a benefit on the microtensile bond strength of these materials. However, sandblasting is crucial to achieve a high bond strength on milled temporary resins.

Resumen Evaluar la resistencia adhesiva en microtracción (µTBS) de dos cementos resinosos a resinas CAD/CAM impresas y fresadas indicadas para restauraciones provisionales. Bloques (5 x 5 x 5mm) de tres resinas impresas (Cosmos3DTemp / Yller; Resilab3D Temp / Wilcos and SmartPrint BioTemp, / MMTech) y una resina fresada (VitaCAD-Temp, VITA) fueron fabricados. La mitad de los especímenes fueron arenados y el resto no recibió tratamiento mecánico. Dos bloques con condiciones de tratamiento iguales fueron cementados con cemento resinoso (PanaviaV5 / Kuraray Noritake y RelyX Ultimate / 3M Oral Care). Después de 24 horas los bloques fueron seccionados en palitos de 1 mm² de área. En la mitad de los especímenes se midió la TBS inmediatamente y el resto fue termociclado (5000 ciclos, 30s remojo, 5s transferencia) antes de la prueba de TBS. Se aplica un análisis estadístico por Modelo Linear General con 4 factores (material*arenado*cemento*termociclado). La resina VITA presentó la menor µTBS, independientemente del cemento usado, el arenado y el termociclado. Sin embargo, el arenado aumentó la µTBS de VIT, especialmente después del termociclado. Por otro lado, el arenado no resultó en un aumento significativo de la µTBS de las resinas impresas. El arenado no fue beneficiosos para las resinas impresas, aunque es un paso crucial para la cementación adhesive de las resinas fresadas. El arenado afecta la integridad de las capas de las resinas impresas, sin generar un beneficio en la TBS.

Impact of untreated dental caries on the daily activities of children.

OBJECTIVES: Untreated dental caries can compromise oral health-related quality of life (OHRQoL). However, it is not clear which specific daily activities related to OHRQoL are compromised by the presence of this problem. Therefore, the purpose of this study was to identify which specific daily activities are affected by the presence of untreated dental caries using a representative sample of Brazilian children. METHODS: A cross-sectional study using a representative sample of Brazilian children (12 years of age) was conducted. The presence of untreated dental caries was assessed using the "decayed - D" component of the DMFT (decayed, missing, and filled teeth) index. Clinical exams were conducted by trained and calibrated dentists. The daily activities were evaluated using the survey Oral Impacts on Daily Performance (OIDP), considering items and domains. Descriptive, bivariate, and multiple analyses were conducted (α = 0.05). RESULTS: A total of 7,247 children were included, and 39.9 percent had at least one tooth with untreated dental caries, with 33.5 percent experiencing an impact on at least one of the OIDP activities. This study identified a greater chance of the presence of untreated dental caries in children having an impact on the psychological domain (P = 0.006), as well as on the "difficulty eating" (P = 0.007), and "difficulty sleeping" (P = 0.023) items. CONCLUSION: The presence of untreated dental caries among Brazilian children was associated with an impact on specific daily activities (difficulty eating and sleeping) and the psychological domain of OHRQoL.

Short-term effect of adhesive system on clinical performance of bulk fill composite: randomized clinical trial

Aim: Although bulk fill composites have been widely used as restorative material, there is no consensus regarding the best clinical protocol in terms of composite technique and adhesive system. Therefore, this clinical trial evaluated the clinical performance of bulk fill composites for class I restorations under different protocols. Methods: A randomized clinical trial including 155 class I restorations was conducted using different adhesive systems: conventional technique (phosphoric acid + conventional three-step adhesive system) (Group 1, 2 and 3); or self-etching adhesive system (Groups 4, 5 and 6). Control groups 1 and 4 were restored with conventional composite; groups 2 and 5 with low viscosity bulk fill and conventional composite as occlusal coverage; groups 3 and 6 with high viscosity bulk fill. The FDI criteria was used for clinical evaluation at baseline and after 6 months. Results: All groups showed good clinical performance. At baseline, the adhesive system did not affect postoperative hypersensitivity. After 6 months, group 5 showed a significant reduction in color and translucency; group 6 a reduction in terms of anatomical form and for postoperative sensitivity and an improvement in patient satisfaction (p<0.05). Considering the same restorative technique, the use of the self-etching adhesive system showed a significant decrease in color and translucency (p<0.05). Conclusion: All groups showed favorable clinical performance, and promising results were found for the conventional adhesive system and high viscosity bulk fill protocol

Effect of Fluoride Concentration on Reduction of Enamel Demineralization According to the Cariogenic Challenge.

Fluoride present in toothpaste at 1,100 µg/g is considered effective on caries control. However, under high cariogenic challenge due to increasing sugar exposure, higher fluoride concentration (5,000 µg/g) could be necessary to compensate the unbalance on caries process. This was tested in a pH-cycling regimen, which evaluated the effect of fluoride concentration relative to toothpaste on reduction of enamel demineralization under conditions of two levels of cariogenic challenge. Enamel slabs (n=20) were subjected to two pH-cycling regimens, simulating 8x and 16x/day sugar exposure and were treated with solutions containing: 0 (no fluoride), 275 or 1,250 µg F/mL, resulting in 6 treatment groups: 4-h/0-F; 8-h/0-F; 4-h/275-F; 8-h/275-F; 4-h/1,250-F and 8-h/1,250-F. The 275 and 1,250 µg F/mL concentrations simulate mouth salivary dilution when 1,100 and 5,000 µg/g toothpastes are used. Enamel demineralization was assessed by surface (%SHL) and cross-sectional hardness. Fluoride taken up by enamel was also evaluated. Data were analyzed by ANOVA one-way and Tukey's test. The treatment with 1,250 µg F/mL significantly reduced %SHL compared with 275 µg F/mL (p<0.05), irrespective the level of cariogenic challenge (4-h/1,250-F vs. 4-h/275-F and 8-h/1,250-F vs 8-h/275-F comparisons, respectively). These data were supported by fluoride concentration found in enamel. These findings suggest that higher fluoride concentrations could partly compensate the greater caries risk under higher cariogenic challenge due to increasing sugar exposure.

Insatisfação com os serviços odontológicos entre idosos brasileiros dentados e edentados: análise multinível / Dissatisfaction with dental services among dentate and edentulous elderly Brazilians: a multilevel analysis

Resumo Avaliou-se a insatisfação com os serviços odontológicos entre idosos brasileiros dentados e edentados e sua associação com variáveis contextuais e individuais. Foram utilizados os dados do Levantamento Nacional de Saúde bucal realizado em 2010 e dados contextuais referentes aos municípios. Análises descritivas, bivariadas e multinível foram realizadas. Incluiu-se 1.989 idosos. Destes, 11,2% dos idosos dentados e 22,1% dos edentados estavam insatisfeitos. Entre os dentados, a insatisfação foi associada com variáveis contextuais (localização do município, índice de desenvolvimento humano, Índice de GINI, presença de Centro de Especialidades Odontológicas e cobertura das equipes de saúde bucal) e individuais pertencentes à atenção à saúde e condições de saúde bucal. Para os idosos edentados, não foi identificado associação com variáveis contextuais. Apenas o motivo do uso do serviço e a satisfação com dentes e boca foram associados. Identificou-se uma prevalência considerável de insatisfação com os serviços, sendo maior entre os idosos edentados. Entre os idosos dentados, foi observado associação com variáveis contextuais.

Abstract The scope of this study was to evaluate dissatisfaction with dental services among dentate and edentulous elderly Brazilians and its association with contextual and individual variables. The data from the National Oral Health Survey conducted in 2010 and contextual variables related to cities were used. Descriptive, bivariate and multilevel analysis was conducted among 1,989 elderly individuals. Of these, 11.2% of dentate and 22.1% of edentulous elderly people were dissatisfied. Among the dentate individuals, dissatisfaction was associated with contextual variables (location of municipality, human development index, GINI Index, the presence of Dental Specialty Centers and the coverage of oral health in public service) and persons related to health care and oral health conditions. For the edentulous individuals, no associated contextual variables were identified. Only the motive for the use of the service and satisfaction with teeth and mouth were associated with dissatisfaction with dental services. A considerable prevalence of dissatisfaction with the services was identified, being higher among edentulous elderly Brazilians. Among dentate elderly Brazilians, an association with contextual variables was detected.

Falta de dentição funcional influencia na autopercepção da necessidade de tratamento em adultos: estudo de base populacional no Brasil / Absence of functional dentition influences self-perception need of dental treatment in adults: population-based study in Brazil

Resumo Introdução A falta de dentição funcional compromete a qualidade de vida dos indivíduos, podendo refletir nas suas percepções, incluindo a autopercepção da necessidade de tratamento odontológico. No entanto, essa relação ainda não é bem esclarecida na literatura. Objetivo Avaliar se a falta de dentição funcional em adultos está associada à autopercepção da necessidade de tratamento odontológico. Método Foi realizado estudo transversal analítico, no qual foram utilizados dados da Pesquisa Nacional de Saúde Bucal, realizada no ano de 2010. A faixa etária avaliada foi de 35 a 44 anos. Após análise bivariada e múltipla, foi verificada a associação entre a falta de dentição funcional e outras variáveis, como a autopercepção da necessidade de tratamento, as condições sociodemográficas e os desfechos em saúde. Resultados Dos 9.564 adultos, aproximadamente 20% dos indivíduos não possuíam dentição funcional. A falta de dentição funcional foi menor em adultos que perceberam a necessidade de tratamento odontológico (OR:0,55; IC95%:0,39-0,75). O sexo feminino (OR:1,76; IC95%:1,39-2,22), a idade mais avançada (OR:2,53; IC95%:2,01-3,18) e a menor escolaridade (OR:0,82; IC95%:0,79-0,85) estavam associados à falta de dentição funcional. Conclusão A falta de dentição funcional é maior em adultos que não têm autopercepção da necessidade de tratamento odontológico.

Abstract Introduction The absence of functional dentition compromises people´s quality of life, reflecting on their perceptions, including the self-perceived need for dental treatment in adults. However, this relation is not very clear in literature. Objective To evaluate if the absence of functional dentition is associated to the self-perceived need for dental treatment in adults. Method Analytical cross-sectional study was performed, in which data of the National Oral Health Survey conducted in 2010 was used. The age group evaluated was 35 to 44 years. After bivariate and multivariate analyzes, the association between the absence of functional dentition and other variables as the self-perceived need for dental treatment, sociodemographic conditions and health endpoints was verified. Results From the 9.564 adults, approximately 20% of the individuals did not show functional dentition. The absence of functional dentition was lower in adults who were aware of the self-perceived need for dental treatment (OR:0.55; IC95%:0.39-0.75). The female gender (OR:1.76; IC95%:1.39-2.22), older age (OR:2.53; IC95%:2.01-3.18) and lower schooling (OR:0.82; IC95%:0.79-0.85) were associated with the absence of functional dentition. Conclusion The absence of functional dentition is greater in adults who do not have self-perceived need for dental treatment.

Effect of Fluoride Concentration on Reduction of Enamel Demineralization According to the Cariogenic Challenge

Abstract Fluoride present in toothpaste at 1,100 µg/g is considered effective on caries control. However, under high cariogenic challenge due to increasing sugar exposure, higher fluoride concentration (5,000 µg/g) could be necessary to compensate the unbalance on caries process. This was tested in a pH-cycling regimen, which evaluated the effect of fluoride concentration relative to toothpaste on reduction of enamel demineralization under conditions of two levels of cariogenic challenge. Enamel slabs (n=20) were subjected to two pH-cycling regimens, simulating 8x and 16x/day sugar exposure and were treated with solutions containing: 0 (no fluoride), 275 or 1,250 µg F/mL, resulting in 6 treatment groups: 4-h/0-F; 8-h/0-F; 4-h/275-F; 8-h/275-F; 4-h/1,250-F and 8-h/1,250-F. The 275 and 1,250 µg F/mL concentrations simulate mouth salivary dilution when 1,100 and 5,000 µg/g toothpastes are used. Enamel demineralization was assessed by surface (%SHL) and cross-sectional hardness. Fluoride taken up by enamel was also evaluated. Data were analyzed by ANOVA one-way and Tukey's test. The treatment with 1,250 µg F/mL significantly reduced %SHL compared with 275 µg F/mL (p<0.05), irrespective the level of cariogenic challenge (4-h/1,250-F vs. 4-h/275-F and 8-h/1,250-F vs 8-h/275-F comparisons, respectively). These data were supported by fluoride concentration found in enamel. These findings suggest that higher fluoride concentrations could partly compensate the greater caries risk under higher cariogenic challenge due to increasing sugar exposure.

Resumo O fluoreto presente em dentifrícios de 1,100 µg/g é considerado efetivo no controle de cárie dental. No entanto, sob alto desafio cariogênico devido ao aumento da exposição ao açúcar, maior concentração de fluoreto (5.000 µg/g) poderia ser necessária para compensar o desequilíbrio no processo de cárie. Isso foi testado em um modelo de ciclagens de pH, que avaliou o efeito da concentração do fluoreto, relacionada ao dentifrício, na redução da desmineralização do esmalte dental sob condição de dois níveis de desafio cariogênico. Blocos de esmalte (n=20) foram submetidos a dois regimes de ciclagens de pH, simulando 8 e 16 exposições diárias ao açúcar, e foram tratados com soluções contendo: 0 (sem flúor), 275 ou 1.250 µg F/mL, resultando em 6 grupos de tratamento: 4-h/0-F; 8-h/0-F; 4-h/275-F; 8-h/275-F; 4-h/1.250-F e 8-h/1.250-F. As concentrações de 275 e 1.250 µg F/mL simularam uma diluição salivar na cavidade bucal quando dentifrícios de 1100 e 5000 µg F/g são usados. A desmineralização do esmalte foi avaliada na superfície (%PDS) e dureza em corte. Fluoreto incorporado pelo esmalte também foi determinado. Os dados foram analisados por Análise de Variância e teste de Tukey. O tratamento com 1.250 µg F/mL reduziu significativamente %PDS comparado ao de 275 µg F/mL (p<0,05), independente do nível do desafio cariogênico (comparações 4-h/1,250-F x 4-h/275-F e 8-h/1,250-F x 8-h/275-F, respectivamente). Esses resultados foram suportados pela concentração de fluoreto encontrada no esmalte. Os resultados sugerem que maior concentração de fluoreto pode parcialmente compensar um maior risco de cárie sob um maior desafio cariogênico provocado pelo aumento de exposição ao açúcar.