Influence of surface sealant and erosive challenge on the color change of composite resin subjected to artificial staining.

The aim of this study was to evaluate the influence of surface sealant and erosive challenge on the color change of composite resin after artificial staining with coffee. Forty-eight composite specimens (8 × 1 mm) were prepared and divided into 4 groups (n = 12) based on the timing of sealant application (immediate vs delayed) and exposure to acid (erosive challenge vs no challenge). The groups were subjected to the procedures in the following order: 1, sealant application, erosive challenge, color measurement, coffee immersion, and color measurement; 2, sealant application, color measurement, coffee immersion, and color measurement; 3, erosive challenge, color measurement, sealant application, coffee immersion, and color measurement; and 4, color measurement, sealant application, coffee immersion, and color measurement. In groups 1 and 2, surface sealant was applied immediately after preparation of the specimens. In groups 3 and 4, sealant was applied after the first color measurement. Color was measured with a spectrophotometer using the CIE L*a*b* system. The erosive challenge (groups 1 and 3) was carried out in 0.01M hydrochloric acid, 150 mL/cycle, at room temperature (2-minute immersions 4 times a day for 5 days). After all specimens were immersed in coffee for 14 days, new color measurements were performed. For total color change (∆E*), groups 1 (21.01) and 2 (23.10) presented lower values than groups 3 (27.76) and 4 (26.57). For luminosity (∆L*), the opposite occurred (groups: 1, -16.84; 2, -17.72; 3, -22.62; and 4, -21.22). For ∆a* and ∆b*, the only statistically significant difference was the group 1 ∆b* value, which was the lowest among all groups. The opacity remained stable in all groups. The results suggest that resin luminosity decreases and color variation increases when surface sealant is applied after erosive cycling and storage.

Effectiveness of whitening mouthwashes on tooth color: an in vitro study.

Products for tooth whitening (or tooth color maintenance) that improve smile esthetics have become increasingly popular due to their easy accessibility and low cost. This in vitro study assessed the effect of whitening mouthwash on bovine tooth color. Forty-eight bovine teeth were divided into 3 immersion groups: SL, artificial saliva (control); CLW, Colgate Luminous White; and OBW, Oral-B 3D White. After prophylaxis with pumice, the initial color was measured using the CIE L*a*b* system. Teeth were immersed in the solutions for 2 minutes, 3 times per day, for 30 days. Changes in color (ΔE*, ΔL*, Δa*, and Δb*) were measured at days 14 and 30. Data were analyzed with 2-way analysis of variance and Tukey test (P < 0.05). At day 30, values of ΔE* had significantly decreased in group SL and increased in group OBW; in addition, at day 30, the ΔE*values in group CLW were significantly greater than those in group SL. The ΔL* values for groups SL and OBW significantly decreased from day 14 to day 30. At day 30, the Δa* and Δb* values were lower in all 3 groups. The results showed that the whitening mouthwashes did not improve color after 14 and 30 days.

Noninvasive esthetic treatment for hypomaturation amelogenesis imperfecta: a case report.

Enamel alterations, such as amelogenesis imperfecta, can compromise the harmony of the smile and the patient's self-esteem and may cause tooth sensitivity. A simple and effective treatment approach uses the natural stratification of composite resins to mask deficient enamel formation and mimic the natural appearance of the substrate. The operative steps and principles for restorative success are described in this case report with 36-month follow-up.

Evaluation of the effect of simvastatin on the progression of alveolar bone loss in experimental periodontitis--an animal study.

AIM: The aim of the present study was to evaluate the effect of simvastatin, a potent antiinflammatory drug, on the progression of alveolar bone loss in an experimental model of periodontitis in rats. MATERIAL AND METHODS: A cotton ligature was used around the lower right first molar in a submarginal position in order to induce experimental periodontitis. Sixty rats were divided into 12 groups consisting of three control groups, three simvastatin groups, three ligature groups, and three ligature plus simvastatin groups. The distance between the cemento-enamel junction and the alveolar crest was determined at the mesial root surfaces of the lower right first molars by radiographic as well as profilometric analyses. RESULTS: In rats of the experimental periodontitis group (ligature), alveolar bone loss was higher compared to the control groups. However, simvastatin was associated with decreased alveolar bone loss in all treatment groups with experimental periodontitis (p < 0.01). CONCLUSION: Simvastatin treatment seems to be a beneficial and supporting therapeutic that favors protection against alveolar bone loss in a model of experimental periodontitis in rats.

Caries-preventive efficacy and retention of a resin-modified glass ionomer cement and a resin-based fissure sealant: a 3-year split-mouth randomised clinical trial.

PURPOSE: This prospective clinical trial compared the retention rate and caries-preventive efficacy of two types of sealant modalities over a 3-year period. MATERIALS AND METHODS: Using a split-mouth randomised design, 1280 sealants were randomly applied on sound permanent second molars of 320 young patients aged between 12 and 16 years. Half of the teeth (n = 640) were sealed with a resin-modified glass ionomer cement (RMGIC) (Vitremer™, 3M ESPE) and the other half (n = 640) with a conventional light-cure, resin-based fissure sealant (LCRB) (Fluoroshield®, Dentsply Caulk). Teeth were evaluated at baseline, 6-, 12-, 18-, 24-, 30- and 36-month intervals with regard to retention and new caries development. RESULTS: On the sealed occlusal surfaces after 3 years, 5.10% of RMGIC and 91.08% of LCRB sealants were totally intact and 6.37% of RMGIC and 7.65% of LCRB sealants were partially intact. New caries lesions were found in 20.06% of RMGIC sealed occlusal surfaces, compared to 8.91% for LCRB sealants. CONCLUSIONS: The findings of the present clinical study suggest that RMGIC should be used only as a transitional sealant that can be applied to newly erupting teeth throughout the eruptive process, whereas LCRB sealants are used to successfully prevent occlusal caries lesions once an effective rubber dam can be achieved. It can be concluded that there are differences between the RMGIC and LCRB sealants over a 3-year period in terms of the retention rate and caries-preventive efficacy. RMGIC can serve as a simple and economic sealing solution, however provisional. Due to its poor retention rate, periodic recalls are necessary, even after 6 months, to eventually replace the lost sealant.

Functional and aesthetic rehabilitation in posterior tooth with bulk-fill resin composite and occlusal matrix.

The restorative procedure in posterior teeth involves clinical steps related to professional skill, especially when using the incremental technique, which may fail in the long term. A recent alternative is bulk-fill resins, which can reduce polymerization shrinkage, decreasing clinical problems such as marginal leakage, secondary caries, and fracture. This scientific study aims to report a clinical case using bulk-fill resin with an occlusal matrix. As determined in the treatment plan, an acrylic resin matrix was produced to establish an improved oral and aesthetic rehabilitation of the right mandibular first molar, which presented a carious lesion with dentin involvement. The occlusal matrix is a simple technique that maintains the original dental anatomy, showing satisfactory results regarding function and aesthetic rehabilitation.

Dental Bleaching, Microabrasion, and Resin Infiltration: Case Report of Minimally Invasive Treatment of Enamel Hypoplasia.

Enamel hypoplasia occurs because of a defect in formation of the organic matrix during the development of tooth enamel. Minimally invasive procedures of the slightly altered enamel contribute to a greater longevity of teeth and prevent them from relapsing into the repetitive restorative cycle. This case history report aimed to show a sequential technique of minimally invasive procedures for esthetic resolution in anterior teeth. Prior to microabrasion, anterior teeth were bleached in office with 37% hydrogen peroxide. Afterwards, hypoplastic spots on the buccal incisal thirds of the maxillary central incisors were treated with two sessions of microabrasion using phosphoric acid and pumice stone and one session using resin infiltrant. Besides a slight remaining white spot on tooth 21, the masking of spots was done with this sequence of treatments, re-establishing color harmony. Spot depth, diagnosis, and the most relevant treatment choice determined the clinical success.

Composite vs. ionomer vs. mixed restoration of wedge-shaped dental cervical lesions: Marginal quality relative to eccentric occlusal loading.

Dental cervical restorations may be impacted by resultants of occlusal loads that may have already contributed to the development of the lesion and should rely on materials' favorable properties to bear the stresses. The marginal quality of cervical restorations made with materials of different moduli of elasticity in essence, isolated, or in combination, was evaluated relative to eccentric occlusal loading. Cervical wedge-shaped cavities, prepared in extracted premolars, were restored with a composite resin (CR), a restorative ionomer (GIC), or the composite in combination with a lining ionomer (Mixed restoration: M). Half of the teeth in each group were subjected to eccentric occlusal loading (eol; 150 N / 106 cycles / 2.5 Hz; CReol / GICeol / Meol, n = 10), and the others were stored in 37 °C distilled water (Control: c; CRc / GICc / Mc, n = 10). A fluorescein-modified adhesive favored delimitation of formed gaps, which were evaluated by confocal laser scanning microscopy regarding their presence, location related to the cavity walls, and width and depth (µm), at a 5% significance level. From a comprehensive perspective, neither the loading nor the materials were significantly associated with the qualitative response variables or exerted any influence over the quantitative variables. More specifically, the use of the different materials was significantly associated with the frequency of gaps exclusively when loading was applied (Chi-square test, p = 0.029, CR > M > GIC). Though the marginal quality of cervical restorations may not be influenced by eccentric occlusal loading or the use of different materials, even in association in general, the unfavorable aspects of the use of the composite may be relevant, particularly in face of the existence of eccentric occlusal loads.

Preemptive use of etodolac on tooth sensitivity after in-office bleaching: a randomized clinical trial.

This study determined the effectiveness of the preemptive administration of etodolac on risk and intensity of tooth sensitivity and the bleaching effect caused by in-office bleaching using 35% hydrogen peroxide. Fifty patients were selected for this tripleblind, randomized, crossover, and placebo-controlled clinical trial. Etodolac (400 mg) or placebo was administrated in a single-dose 1 hour prior to the bleaching procedure. The whitening treatment with 35% hydrogen peroxide was carried out in two sessions with a 7-day interval. Tooth sensitivity was assessed before, during, and 24 hours after the procedure using the analog visual scale and the verbal rating scale. Color alteration was assessed by a bleach guide scale, 7 days after each session. Relative risk of sensitivity was calculated and adjusted by session, while overall risk was compared by the McNemar's test. Data on the sensitivity level of both scales and color shade were subjected to Friedman, Wilcoxon, and Mann-Whitney tests, respectively (α=0.05). The preemptive administration of etodolac did not affect the risk of tooth sensitivity and the level of sensitivity reported, regardless of the time of evaluation and scale used. The sequence of treatment allocation did not affect bleaching effectiveness, while the second session resulted in additional color modification. The preemptive administration of etodolac in a single dose 1 hour prior to in-office tooth bleaching did not alter tooth color, and the risk and intensity of tooth sensitivity reported by patients. A single-dose preemptive administration of 400 mg of etodolac did not affect either risk of tooth sensitivity or level of sensitivity reported by patients, during or after the in-office tooth bleaching procedure.

Effect of two erosive protocols using acidic beverages on the shear bond strength of orthodontic brackets to bovine enamel.

OBJECTIVE: To assess the short-term effect of two in vitro erosive challenge protocols on the bond strength of metal orthodontic brackets on bovine enamel. METHODS: Sixty bovine incisors were selected and randomly divided into six groups: AS7 (artificial saliva - 7 days, Control Group); CC7 (Coca-Cola™ - 7 days); LJ7 (lime juice - 7 days); AS30 (artificial saliva - 30 days, Control Group); CC30 (Coca-Cola™ - 30 days); LJ30 (lime juice - 30 days). Microhardness testing was performed prior to the erosive challenge to verify the standardization of samples. Immersion was performed 4x/day for five minutes, for either 7 or 30 days. After immersions were concluded, the brackets were bonded and shear bond strength was assessed after 48 hours. The Adhesive Remnant Index (ARI) was also assessed. Data were analyzed by two-way ANOVA, followed by Tukey's post-hoc and Student's t test for paired samples, and the Kruskal-Wallis non-parametric test (α = 5%). RESULTS: The mean and standard deviation of microhardness testing of total samples were 281.89 ± 44.51 KHN. There was no statistically significant difference in shear bond strength for the time factor (7 or 30 days; F5.54= 0.105; p  = 0.901). However, there was a statistically significant difference for the solution factor (F5.54= 6.671; p  = 0.003). These differences occurred among solutions of Saliva x Coca-Cola™ (p  = 0.003) and Coca-Cola™ x Lime Juice (p = 0.029). The assessment of the Adhesive Remnant Index showed no significant difference between groups. CONCLUSIONS: The immersion time used in the erosion protocols did not affect the bond strength of brackets to teeth. Coca-Cola™ induced significantly higher shear bond strength values than lime juice and artificial saliva. However, the short term effects of 7/30 days in this in vitro study may not be extrapolated for in vivo ones. Clinical studies should be conducted, substantiating the laboratory results.

Influence of dental erosion on shear bond strength of ceramic brackets bonded with two different adhesive systems: an in vitro study

This study aimed to analyze the shear bond strength (SBS) of ceramic orthodontic brackets bonded with two different adhesive systems to intact and eroded teeth. Ceramic brackets were bonded to 72 bovine central incisors divided into four groups, defined by two study factors: enamel condition (control group, kept in artificial saliva; and experimental group, eroded by using immersion cycles in Coke™ for 90 seconds, every six hours for five days), and adhesive system type (Transbond™ XT or Transbond™ Plus Color Change). Polycrystalline ceramic brackets were adhesively fixed on all specimens using the same light curing protocol. SBS was tested using 0.5 mm/min and the failure mode was classified. SBS data was analyzed using two-way ANOVA followed by Tukey test. The adhesive remnant index (ARI) scores were analyzed using Kruskal-Wallis test with Dunn's post-hoc pairwise comparison (α=0.05). Percentages of ARI scores between the groups were compared by Fisher's exact test. Spearman's correlation coefficient was applied to investigate the correlation between ARI scores and SBS values. Only the adhesive system factor had significant effect on SBS (p=0.014), Transbond™ Plus Color Change showing higher values. No significance was found for enamel condition (p=0.665) or the interaction between adhesive system and enamel condition (p=0.055). ARI scores frequencies differed between groups (p<0.001). The median ARI scores were statistically different for most comparisons among the groups. However, no significant correlation was found between ARI scores and SBS. In conclusion, the type of adhesive system affected the SBS of ceramic brackets to dental enamel, but the enamel condition, intact or eroded, had no significant effect. There was no correlation between ARI scores and SBS values, although eroded enamel tended to retain more adhesive after bracket removal.

Effect of preventive use of nonsteroidal anti-inflammatory drugs on sensitivity after dental bleaching: a systematic review and meta-analysis.

BACKGROUND: Tooth sensitivity associated with bleaching remains a challenge for clinicians. Inflammatory mediators released by the penetration of bleaching agents into dental tissues can sensitize nociceptors, leading to tooth sensitivity. TYPE OF STUDIES REVIEWED: In this systematic review, the authors included randomized clinical trials in which the investigators compared the preventive use of nonsteroidal anti-inflammatory drugs (NSAIDs) with a placebo for sensitivity after dental bleaching. The authors included only studies in which the investigators evaluated in-office tooth bleaching with high-concentration hydrogen peroxide and reported the risk or the level of tooth sensitivity after bleaching. RESULTS: The authors included 3 studies and evaluated the levels of sensitivity reported at up to 1 hour after the procedure and from 1 to 24 hours after bleaching. The authors also calculated the pooled relative risk for the effect of preventive use of NSAIDs on sensitivity after dental bleaching. Preventive analgesia with NSAIDs did not have a significant effect on the risk of sensitivity after dental bleaching or on the levels of sensitivity reported by patients. PRACTICAL IMPLICATIONS: There is insufficient evidence about the use of NSAIDs to prevent tooth sensitivity caused by in-office bleaching procedures.

Randomized controlled trial of sealed in-office bleaching effectiveness.

Regardless of the high success rate, patients commonly report the occurrence of tooth sensitivity during the in-office bleaching procedures. Recently, it has been demonstrated that using a customized tray (called sealed in-office bleaching technique) reduces peroxide penetration. The aim of this randomized clinical study was to evaluate tooth sensitivity and bleaching efficacy of sealed bleaching, in comparison with a conventional in-office technique. Twenty patients were randomized allocated in two groups in which 35% hydrogen peroxide gel was used in a single 45-min application. For the sealed technique, a customized bleaching tray was fabricated and carefully positioned over the bleaching agent during the session. The color was recorded at a baseline, 7 and 28 days after the bleaching session, using Vita Easy Shade spectrophotometer. Tooth sensitivity was recorded during (20 and 40 min) and immediately after the treatment using a visual analogue scale. The bleaching efficacy was evaluated by repeated-measures ANOVA, while the absolute risk of tooth sensitivity and its intensity were evaluated by Fisher's exact and Mann-Whitney tests, respectively (α=0.05). No significant difference on bleaching efficacy was observed between the conventional (7.4 and 8.1 ΔE) and sealed techniques (7.8 and 8.3 ΔE) at both evaluation periods. No significant difference was observed regarding the absolute risk of tooth sensitivity (p=0.15). Sealed technique showed a significant decrease of sensitivity intensity after 40 min (p=0.03). Sealed bleaching technique was able to reduce the sensitivity intensity during the bleaching procedure, without jeopardizing the bleaching efficacy.

Bond strength to ZLS ceramics at different etching times and cementation protocols after aging / Influência da cimentação e da termociclagem na resistência de união da cerâmica de silicato de lítio reforçada com zircônia

Objective: To assess the influence of 5% hydrofluoric acid etching time (ET), cementation protocol (CP), and thermal cycling (TC) aging on the microshear bond strength (µSBS) of zirconia reinforced lithium silicate ceramic (ZLS) to adhesive resin cement. Material and Methods: Ten VITA Suprinity® ceramic blocks were cut in 120 slices (1.4 mm thickness) and randomly assigned to 12 groups (n = 10) according to the combination of factors (2x3x2 design): etching time (20 or 30 s), cementation protocol (silane + universal adhesive + resin cement; universal adhesive + resin cement; silane + resin cement) and thermal cycling (cycled or no-cycled). RelyX Ceramic Primer and Scotchbond™ Universal Adhesive were used respectively as silane (S) and universal adhesive (Ua). Ceramic surface was etched, and the cementation protocol performed on the delimited bonding area. Then, resin cement (RelyX™ Ultimate Cement [Rc]) cylinders were bonded and light cured. After, specimens were stored in deionized water at 37°C for 7 days and subjected to the µSBS test. Results: Data passed the normality test and three-way ANOVA analysis showed statistical difference (p < 0.01) for isolated; double (ET/TC) (p < 0.05), and triple (p < 0.05) factor interactions. Conclusion: The combination 30s etching-Ua-Rc presented higher adhesive bond strength after thermal aging. (AU)

Objetivo: Avaliar a influência do tempo de condicionamento com ácido fluorídrico 5% (ET), protocolo de cimentação (CP), e envelhecimento por termociclagem (TC) na resistência de união ao microcisalhamento (µSBS) da cerâmica de silicato de lítio reforçada com zircônia (ZLS) ao cimento resinoso adesivo. Material e Método: Dez blocos da cerâmica VITA Suprinity® foram cortados e 120 fatias (com espessura de 1,4 mm) e distribuídos aleatoriamente em 12 grupos (n=10) de acordo com o fator de combinação (2x3x2): tempo de condicionamento (20 ou 30 s), protocolo de cimentação (silano + adesivo universal + cimento resinoso; adesivo universal + cimento resinoso; silano + cimento resinoso) e ciclagem térmica (ciclado ou não ciclado). RelyX Ceramic Primer e adesivo Scotchbond™ Universal foram utilizados respectivamente como silano (S) e adesivo universal (Ua). A superfície cerâmica foi condicionada e o protocolo de cimentação aplicado sobre área de cimentação delimitada. Portanto, cilindros de cimento resinoso (cimento RelyX™ Ultimate [Rc]) foram cimentados e fotopolimerizados. Após, os espécimes foram armazenados em água deionizada a 37°C por 7 dias e submetidos ao teste de µSBS. Resultados: Após teste de normalidade, os dados foram analisados pelo teste ANOVA três critérios mostrando diferença estatística (p < 0.01) para a análise do fator isolado; para a interação entre dois fatores (ET/TC) (p < 0.05), e interação entre os três fatores (p < 0.05). Conclusão: A combinação 30s de condicionamento-Ua-Rc apresentou a maior resistência de união adesiva após a ciclagem térmica.(AU)

Effect of two erosive protocols using acidic beverages on the shear bond strength of orthodontic brackets to bovine enamel

Abstract Objective: To assess the short-term effect of two in vitro erosive challenge protocols on the bond strength of metal orthodontic brackets on bovine enamel. Methods: Sixty bovine incisors were selected and randomly divided into six groups: AS7 (artificial saliva - 7 days, Control Group); CC7 (Coca-Cola™ - 7 days); LJ7 (lime juice - 7 days); AS30 (artificial saliva - 30 days, Control Group); CC30 (Coca-Cola™ - 30 days); LJ30 (lime juice - 30 days). Microhardness testing was performed prior to the erosive challenge to verify the standardization of samples. Immersion was performed 4x/day for five minutes, for either 7 or 30 days. After immersions were concluded, the brackets were bonded and shear bond strength was assessed after 48 hours. The Adhesive Remnant Index (ARI) was also assessed. Data were analyzed by two-way ANOVA, followed by Tukey's post-hoc and Student's t test for paired samples, and the Kruskal-Wallis non-parametric test (α = 5%). Results: The mean and standard deviation of microhardness testing of total samples were 281.89 ± 44.51 KHN. There was no statistically significant difference in shear bond strength for the time factor (7 or 30 days; F5.54= 0.105; p = 0.901). However, there was a statistically significant difference for the solution factor (F5.54= 6.671; p = 0.003). These differences occurred among solutions of Saliva x Coca-Cola™ (p = 0.003) and Coca-Cola™ x Lime Juice (p= 0.029). The assessment of the Adhesive Remnant Index showed no significant difference between groups. Conclusions: The immersion time used in the erosion protocols did not affect the bond strength of brackets to teeth. Coca-Cola™ induced significantly higher shear bond strength values than lime juice and artificial saliva. However, the short term effects of 7/30 days in this in vitro study may not be extrapolated for in vivo ones. Clinical studies should be conducted, substantiating the laboratory results.

Resumo Objetivo: avaliar o efeito de curto prazo de dois protocolos de desafio erosivo, in vitro, na resistência adesiva de braquetes ortodônticos metálicos em esmalte bovino. Métodos: Sessenta incisivos bovinos foram selecionados e divididos aleatoriamente em seis grupos: SA7 (saliva artificial - 7 dias, Grupo Controle); CC7 (Coca-Cola® - 7 dias); SL7 (suco de limão - 7 dias); SA30 (saliva artificial - 30 dias, Grupo Controle); CC30 (Coca-Cola® - 30 dias); SL30 (suco de limão - 30 dias). Foi realizado o teste de microdureza antes do desafio erosivo, para verificar a padronização das amostras. A imersão foi realizada quatro vezes ao dia, por cinco minutos, durante 7 ou 30 dias. Finalizadas as imersões, os braquetes foram colados e, após 48 horas, foi avaliada a resistência ao cisalhamento. O Índice de Adesivo Remanescente (IAR) também foi avaliado. Para análise dos dados, foram utilizados os testes ANOVA dois fatores, seguido do post-hoc de Tukey e teste t de Student para amostras pareadas, e o teste não-paramétrico de Kruskal-Wallis (α?#8197;= 5%). Resultados: a média e o desvio-padrão do teste de microdureza das amostras totais foi igual a 281,89 ± 44,51 KHN. Não houve diferença estatisticamente significativa na resistência ao cisalhamento para o fator tempo (7 ou 30 dias; F5,54= 0,105; p= 0,901). Contudo, houve diferença estatisticamente significativa para o fator solução (F5,54=6,671; p= 0,003). Essas diferenças ocorreram entre as soluções de Saliva x Coca-Cola® (p= 0,003) e Coca-Cola® x suco de limão (p= 0,029). Ao avaliar o Índice de Adesivo Remanescente, não foi possível verificar diferença significativa entre os grupos. Conclusões: o tempo de imersão utilizado nos protocolos de erosão não afetou a resistência de união dos braquetes aos dentes. A Coca-Cola® induziu valores de resistência ao cisalhamento significativamente mais altos do que o suco de limão e a saliva artificial. No entanto, os efeitos em curto prazo de 7 e 30 dias, nesse estudo in vitro, não podem ser extrapolados para os estudos in vivo. Estudos clínicos devem ser conduzidos, fundamentando os resultados laboratoriais.

Preemptive use of etodolac on tooth sensitivity after in-office bleaching: a randomized clinical trial

Abstract Purpose: This study determined the effectiveness of the preemptive administration of etodolac on risk and intensity of tooth sensitivity and the bleaching effect caused by in-office bleaching using 35% hydrogen peroxide. Material and methods: Fifty patients were selected for this tripleblind, randomized, crossover, and placebo-controlled clinical trial. Etodolac (400 mg) or placebo was administrated in a single-dose 1 hour prior to the bleaching procedure. The whitening treatment with 35% hydrogen peroxide was carried out in two sessions with a 7-day interval. Tooth sensitivity was assessed before, during, and 24 hours after the procedure using the analog visual scale and the verbal rating scale. Color alteration was assessed by a bleach guide scale, 7 days after each session. Relative risk of sensitivity was calculated and adjusted by session, while overall risk was compared by the McNemar's test. Data on the sensitivity level of both scales and color shade were subjected to Friedman, Wilcoxon, and Mann-Whitney tests, respectively (α=0.05). Results: The preemptive administration of etodolac did not affect the risk of tooth sensitivity and the level of sensitivity reported, regardless of the time of evaluation and scale used. The sequence of treatment allocation did not affect bleaching effectiveness, while the second session resulted in additional color modification. The preemptive administration of etodolac in a single dose 1 hour prior to in-office tooth bleaching did not alter tooth color, and the risk and intensity of tooth sensitivity reported by patients. Conclusion: A single-dose preemptive administration of 400 mg of etodolac did not affect either risk of tooth sensitivity or level of sensitivity reported by patients, during or after the in-office tooth bleaching procedure.

Clinical strategies for esthetic excellence in anterior tooth restorations: understanding color and composite resin selection.

Direct composite resin restorations have become a viable alternative for patients that require anterior restorative procedures to be integrated to the other teeth that compose the smile, especially for presenting satisfactory esthetic results and minimum wear of the dental structure. Technological evolution along with a better understanding of the behavior of dental tissues to light incidence has allowed the development of new composite resins with better mechanical and optical properties, making possible a more artistic approach for anterior restorations. The combination of the increasing demand of patients for esthetics and the capacity to preserve the dental structure resulted in the development of different incremental techniques for restoring fractured anterior teeth in a natural way. In order to achieve esthetic excellence, dentists should understand and apply artistic and scientific principles when choosing color of restorative materials, as well as during the insertion of the composite resin. The discussion of these strategies will be divided into two papers. In this paper, the criteria for color and material selection to obtain a natural reproduction of the lost dental structures and an imperceptible restoration will be addressed.

Thermal-induced polymerization shrinkage in silorane versus methacrylate based resin composite / Contração de polimeração induzida termicamenteem resinas compostas a base de silorano e metacrilato

Shrinkage is a limitation of resin composite, compromising the clinical longevity of the restorative procedure. In an attempt to reduce their harmful effects, researchers have studied monomers with lower values of contraction. As a result, low-shrinkage composites were developed. This study evaluated quantitatively the shrinkage as a function of power density increase based on methacrylates, comparing them with silorane based resin, and qualitatively regarding gap formation between the adhesive interface as function of tooth substrate. Resin Filtek P90 and Filtek Z250 were polymerized with the device Blue Star 3 with 200, 400, 600, 800 and 1000 mW/cm2 keeping volume constant in 12 mm3. For qualitative analysis of restorative interface, class V cavity preparations in bovine incisors were restored in (2x2x2 mm3), photoactivated with the same values of irradiance, and analyzed by scanning electron microscopy at the interface of the wall surrounding enamel, dentin and axial. The quantitative results of the polymerization shrinkage were analyzed by two-way ANOVA and Tukey's test (p<0.05), while qualitative data were submitedd to Mann-Whitney's, Kruskal-Wallis' and Miller's tests. The progressive increase in power density directly influenced the polymerization shrinkage of the materials studied, although the silorane based resin demonstrated significantly lower values. The marginal integrity was influenced by the dental substrate and the power density used.

Este estudo avaliou quantitativamente a contração de polimerização em função do aumento dos valores de densidade de potência irradiados em compósitos à base de metacrilatos e silorano, e qualitativamente a interface restauradora em relação à abertura de fendas marginais, em função da variação do tipo de substrato dentário. As resinas Filtek Z250 e Filtek P90 foram fotoativadas com 200, 400, 600, 800 e 1000 mW/cm2, em um volume constante de 12mm3, e os valores de contração foram aferidos por meio da máquina de ensaios universal. Para análise qualitativa da interface restauradora, preparos cavitários classe V de (2x2x2mm3) foram restaurados em incisivos bovinos, fotoativados com os mesmos valores de irradiância, e analisados em microscopia eletrônica de varredura nas interfaces da parede circundante em esmalte, parede circundante em dentina e parede axial. Os resultados quantitativos da contração de polimerização foram analisados pelo teste ANOVA a dois critérios e Tukey (p<0,05) enquanto para os dados qualitativos os testes Mann- Whitney, Kruskal-Wallis e Miller foram empregados. O aumento progressivo da densidade de potência influenciou diretamente na contração de polimerização dos materiais estudados, não obstante a resina composta à base de silorano ter demonstrado valores significativamente menores. A integridade marginal sofreu influência do substrato dentário bem como da densidade de potência utilizada, para as duas resinas estudadas.

Conservative approaches for the management of failed resin-based posterior restorations: a case report.

Composite resin restorations have been shown to be functionally reliable and esthetically acceptable to patients, primarily due to improvements in their chemicophysical characteristics. Nevertheless, clinical limitations, such as marginal discoloration, disadaptation, and microleakage, are observed in some patients with these restorations. The choice of treatment pursued to repair such restorations depends primarily on the analysis of the compromised restoration with regard to these aforementioned imperfections. The most common procedures invoked to treat compromised restorations include resurfacing, repairing the restoration with or without the use of surface sealants, and completely replacing the compromised restoration. This case report describes the proper implementation of a simple technique, known as composite resin posterior restoration, that yields a satisfactory outcome for patients who have been characterized with these clinical limitations.

Effect of the polishing procedures on color stability and surface roughness of composite resins.

Objectives. To evaluate the polishing procedures effect on color stability and surface roughness of composite resins. Methods. Specimens were distributed into 6 groups: G1: Filtek Supreme XT + PoGo; G2: Filtek Supreme XT + Sof-Lex; G3: Filtek Supreme XT + no polishing; G4: Amelogen + PoGo; G5: Amelogen + Sof-Lex.; G6: Amelogen + no polishing. Initial color values were evaluated using the CIELab scale. After polishing, surface roughness was evaluated and the specimens were stored in coffee solution at 37°C for 7 days. The final color measurement and roughness were determined. Results. Sof-Lex resulted in lower staining. Amelogen showed the highest roughness values than Filtek Supreme on baseline and final evaluations regardless of the polishing technique. Filtek Supreme polished with PoGo showed the lowest roughness values. All groups presented discoloration after storage in coffee solution, regardless of the polishing technique. Conclusion. Multiple-step polishing technique provided lower degree of discoloration for both composite resins. The final surface texture is material and technique dependent.