Curing potential and color stability of different resin-based luting materials.

PURPOSE: To determine the curing potential and color stability of resin-based luting materials for aesthetic restorations. MATERIAL AND METHODS: Four resin-based luting agents were tested: traditional dual-activated resin cement (RelyX ARC, ARC), amine-free dual-activated resin cement (RelyX Ultimate, ULT), light-activated resin cement (RelyX Veneer, VEN), and pre-heated restorative resin composite (Filtek Supreme, PHC). Degree of C=C conversion was determined by infrared spectroscopy (n=3) with direct light exposure or with interposition of 1.5-mm-thick ceramic (e.max Press HT) between the luting material and light. The curing potential considered the ratio between these two scenarios. Color difference (n=6) was determined by CIELAB (ΔEab) and CIEDE2000 (ΔE00) methods, by spectrophotometer measurements made 24h after photoactivation and 90 days after storage in water. Data was submitted to ANOVA and Tukey's test (α=0.05). RESULTS: The luting agents affected both conversion and color stability. With ceramic, ARC produced the highest conversion among the tested groups (75±1%) and the pre-heated composite (PHC) the lowest one (51±3%), but the curing potential was similar for all materials. ULT produced lower ΔEab than ARC. PHC presented the lowest color difference when considered both CIELAB and CIE2000 methods (ΔEab 2.1±0.4; ΔE00 1.6±0.2). SIGNIFICANCE: All luting strategies presented high curing potential. Amine-free dual-activated material was able to reduce color difference than that formulated with the amine component. Pre-heated composite produced the least color variation after storage.

Does translucency influence cure efficiency and color stability of resin-based composites?

OBJECTIVE: To determine if material's translucency influences the cure efficiency and color stability of resin-based composites (RBCs). METHODS: Four commercially-available RBCs indicated for aesthetic restorations were selected in different translucent/opaque shades: IPS Empress Direct (IED) A3 Dentin, A3 Enamel, Trans 20, and Trans 30; Filtek Z350 XT (FZX) A3D, A3B, A3E, and CT; Estelite ∑ Quick (EQ) OA3, A3, and CE; and Opallis (OP) DA3, EA3, and T-Neutral. Color was obtained in the L'C'h' system at three distinct periods: 24h after photoactivation (baseline), after 30d of water storage (WS), and after 30d of coffee storage (CS). The translucency parameter (TP) of each RBC was calculated at baseline. The degree of CC conversion (DC) was obtained by Fourier-transform infrared spectroscopy at 0.05mm (top) and 2mm (bottom) surfaces; the cure efficiency considered the bottom/top ratio. The CIEDE2000 color difference (ΔE00) was calculated considering the WS-baseline and CS-baseline values. Data were submitted to two-way ANOVA and Tukey's post-hoc test (α=0.05). Pearson's tests were used to analyze the correlations between TP and DC, and between TP and ΔE00. RESULTS: For all RBCs, cure efficiency was not affected by materials' translucency. A positive, significant correlation was observed between TP and DC at the bottom surface for FZX only. For all RBCs, the higher the TP, the higher the ΔE00. The ΔE00 was higher after CS than after WS, except for EQ A3. Positive correlation between TP and ΔE00 were observed for all materials. CONCLUSION: The translucency did not influence the cure efficiency but affected the color stability for all RBCs. CLINICAL SIGNIFICANCE: High-translucent RBCs presented lower color stability and should be used carefully.

In situ evaluation of color stability and hardness' decrease of resin-based composites.

OBJECTIVE: To determine the color stability (CS) and hardness' decrease (HD) of two commercial resin-based composites (RBCs), after in situ staining conditions (SC). METHODS: Six disc-shaped specimens (6 × 2 mm) of two RBCs-Filtek Z350 XT (FZX) and IPS Empress Direct (IED)-were randomly distributed into palatal devices. Eight volunteers (aged 20-30 years) participated in this study. The in situ SC consisted of 400 mL consumption (2 × 200 mL/day) of water, orange juice, cola soda, and coffee and 140 mL consumption of red wine, 10 days each. CS was obtained by CIELAB color difference (ΔE*) and HD (in %) by the Knoop method (50 g for 15 s), after curing (baseline) and after the in situ SC. Data were statistically analyzed at α = 0.05 significance level. RESULTS: For both RBCs, the coffee (5.7 ± 0.5 for FZX; 5.9 ± 1.3 for IED) and red wine (6.1 ± 1.1 for FZX; 6.2 ± 1.6 for IED) groups showed the highest ΔE* while water the lowest (1.6 ± 0.6 for FZX; 1.8 ± 0.2 for IED). The highest HD was induced by red wine group for FZX (40.7 ± 5.4) and by cola soda for IED (40.6 ± 3.2) while the water groups (8.3 ± 1.7 for FZX; 7.8 ± 2.1 for IED) presented the lowest values for both RBCs. CONCLUSION: Both RBCs were affected by the in situ SC, but no significant differences for CS and HD were observed between them. Red wine and coffee showed higher discoloration potential. CLINICAL SIGNIFICANCE: This in situ study suggests that color stability and hardness' decrease of resin-based composites were dependent on the type of consumed beverage and materials' composition. Patients with esthetic direct restorations should be aware of the degradative potential of them.

Influence of Photoinitiator System on Physical-Chemical Properties of Experimental Self-Adhesive Composites.

The aim of this study was to determine the influence of photoinitiator systems on physical-chemical properties of flowable composites. Conventional (CFC), composed by bisphenol-glycidyl dimethacrylate (BisGMA)+triethyleneglycol dimethacrylate (TEGDMA), and self-adhesive (SAFC), composed by BisGMA+TEDGMA+bis{2-(methacryloyloxy) ethyl} phosphate (2MP), flowable composites were developed. Five photoinitiator systems were tested: camphorquinone (CQ), ethyl-4-dimethylaminobenzoate (EDMAB), diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), phenylbis (2,4,6-trimethylbenzoyl)phosphine oxide (BAPO), CQ+EDMAB+TPO and CQ+EDMAB+BAPO. A two-peak LED was used; degree of conversion (DC) and the maximum polymerization rate (RPmax) were determined by near infrared spectroscopy. For the yellowing degree a spectrophotometer was used. Water sorption (Wsp) was obtained after 30 days of water storage (n=5). Data were submitted to two-way analysis of variance and Tukey's test (a=0.05). BAPO presented the highest DC and RPmax values for both series. SAFCs presented lower DC and RPmax for CQ+EDMAB-based materials. Greater yellowing was observed for SAFCs compared with CFCs, except for BAPO. Greater Wsp was observed for SAFCs compared with CFCs. The photoinitiator did not influence Wsp for CFCs, but TPO and BAPO presented the highest Wsp in SAFCs. The photoinitiator system affected differently the physical-chemical properties of CFCs and SAFCs.

Degradation of optical and surface properties of resin-based composites with distinct nanoparticle sizes but equivalent surface area.

OBJECTIVE: To determine the optical and surface properties of model resin-based composites made with distinct nanoparticle sizes but equalized surface area, among them, before and after ageing. METHODS: Model resin-based composites based on BisGMA/TEGDMA (50:50mol%) were loaded with three different fumed silica filler content (7nm/examethyldisilazane, 12nm/octylsilane, and 16nm/dimethylchlorosilane), but with equivalent surface area (BET method). The optical and surface properties of the disk-shaped specimens were measured in 24h after photoactivation (baseline) and repeated after water storage (90days at 37°C), and after abrasion (20,000 cycles of brushing). CIELAB individual parameters, color difference (ΔE*ab), translucency parameter (TP), gloss (G.U.) and roughness (Ra parameter) were measured. Data were statistically analyzed at α=0.05 significance level. RESULTS: CIE L* and TP were not affected by ageing in any group. CIE a* was increased and CIE b* decreased for the 12nm and 16nm groups and did not show any difference for the 7nm group. After ageing, the lowest ΔE*ab was observed for the 7nm group. Gloss and roughness were statistically equivalent for all groups, before and after ageing. The water storage didn't show any significant difference while the abrasion decreased gloss and increased the roughness. CONCLUSION: The optical properties of the tested materials were not dependent of the fillers' surface area, while the surface properties were. CLINICAL SIGNIFICANCE: Several factors influence the ageing resistance of the resin-based composites, including the surface area of the fillers and the amount and coupling treatment of them. The improvement of the material's physical stability could avoid the premature replacement of dental restorations.

Influence of Photoinitiator System on Physical-Chemical Properties of Experimental Self-Adhesive Composites

Abstract The aim of this study was to determine the influence of photoinitiator systems on physical-chemical properties of flowable composites. Conventional (CFC), composed by bisphenol-glycidyl dimethacrylate (BisGMA)+triethyleneglycol dimethacrylate (TEGDMA), and self-adhesive (SAFC), composed by BisGMA+TEDGMA+bis{2-(methacryloyloxy) ethyl} phosphate (2MP), flowable composites were developed. Five photoinitiator systems were tested: camphorquinone (CQ), ethyl-4-dimethylaminobenzoate (EDMAB), diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), phenylbis (2,4,6-trimethylbenzoyl)phosphine oxide (BAPO), CQ+EDMAB+TPO and CQ+EDMAB+BAPO. A two-peak LED was used; degree of conversion (DC) and the maximum polymerization rate (RPmax) were determined by near infrared spectroscopy. For the yellowing degree a spectrophotometer was used. Water sorption (Wsp) was obtained after 30 days of water storage (n=5). Data were submitted to two-way analysis of variance and Tukey’s test (a=0.05). BAPO presented the highest DC and RPmax values for both series. SAFCs presented lower DC and RPmax for CQ+EDMAB-based materials. Greater yellowing was observed for SAFCs compared with CFCs, except for BAPO. Greater Wsp was observed for SAFCs compared with CFCs. The photoinitiator did not influence Wsp for CFCs, but TPO and BAPO presented the highest Wsp in SAFCs. The photoinitiator system affected differently the physical-chemical properties of CFCs and SAFCs.

Resumo O objetivo do estudo foi determinar a influência do sistema fotoiniciador sobre as propriedades físico-químicas de compósitos fluidos. Os compósitos convencionais foram compostos por bisfenol-glicidil dimetacrilato (BisGMA) + trietilenoglicol dimetacrilato (TEGDMA), e os autoadesivos, apresentavam BisGMA +TEGDMA+ Bis2(metacriloiloxi)etil fosfato (2 MP). Cinco sistemas fotoiniciadores foram testados: canforquinona + etil-4- dimetilamino benzoato (CQ+EDMAB), óxido mono-alquil fosfínico (TPO) e óxido bis-alquil fosfínico (BAPO), CQ+EDMAB+TPO e CQ+EDMAB+BAPO. LED de amplo espectro foi usado; o grau de conversão (GC) e a taxa de polimerização (TP) foram determinados por espectroscopia próximo ao infravermelho; o grau de amarelo foi mensurado por um espectrofotômetro e absorção de água foi obtida após 30 dias de armazenamento em água (n=5). Os dados foram submetidos a análise de variância de dois fatores e teste de Tukey (?=0,05). BAPO apresentou os maiores valores de GC e TP nos compósitos convencionais e autoadesivos. Compósitos autoadesivos apresentaram menor GC e TP quando CQ+EDMAB foi usado. Maior amarelecimento foi observado nos compósitos autoadesivos em relação aos convencionais, exceto para BAPO. Compósitos autoadesivos promoveram maior absorção de água. Não houve influência dos fotoiniciadores nos compósitos convencionais, no entanto TPO e BAPO apresentaram os maiores valores de absorção de água nos compósitos autoadesivos. Os sistemas fotoiniciadores influenciaram de maneira diferente as propriedades físico-químicas dos compósitos convencionais e autoadesivos.

Reabilitação oral estética com laminados cerâmicos ultrafinos / Aesthetic oral rehabilitation with ultrathin ceramic veneers

A utilização de laminados cerâmicos ultrafinos nas reabilitações orais estéticas tem-se tornado uma opção de tratamento cada vez mais popular. Entretanto não há elevado nível de evidência científica quanto à longevidade dessas restaurações. Com base nisso, o objetivo do presente artigo é relatar a instalação de laminados cerâmicos ultrafinos na bateria labial superior de uma paciente com queixa de insatisfação estética do sorriso após ter finalizado um tratamento ortodôntico, destacando aspectos relacionados ao diagnóstico, ao planejamento do caso e ao preparo dentário...

The use of ultrathin ceramic veneers for the aesthetic oral rehabilitation has become an increasingly popular treatment. However, there is few high-quality scientific evidence regarding the longevity of these restorations. Based on this fact, the purpose of this study is to report a clinical case of ultra-thin ceramic veneers in the maxillary teeth of a patient unsatisfied with her smile after the end of the orthodontic treatment, highlighting aspects related to diagnosis, treatment planning and tooth preparation...

Effect of photoinitiator combinations on hardness, depth of cure, and color of model resin composites.

OBJECTIVE: This study aims to determine the influence of photoinitiators' combinations on the hardness, depth of cure, and color of model resin composites. MATERIALS AND METHODS: The composites were formulated by a mixture of BisGMA and triethyleneglycol dimethacrylate (60:40 mol), with barium-aluminum-silicate glass and silicon dioxide particles as inorganic fillers (60 wt%). Three photoinitiator types were tested: camphorquinone/amine (CQ), monoacylphosphine oxide (TPO), and bysacylphosphine oxide (BAPO). Six experimental groups were formed by differences in photoinitiator systems: CQ, TPO, BAPO, CQ+TPO, CQ+BAPO, and CQ+TPO+BAPO. Hardness was determined by Knoop indentation at the top and bottom surfaces (n = 5). Depth of cure was performed according to ISO 4049 scraping method (n = 5). Color was obtained by the CIELAB method (n = 10), 24 hours after curing (baseline), after 30 days storage in distilled water, and after 30 days storage in coffee solution. CIELAB color difference (ΔE*) was calculated for both periods. Data were submitted to analysis of variance, followed by Student-Newman-Keuls method (α = 0.05). RESULTS: The photoinitiator system influenced hardness, where CQ presented the lowest top and bottom values. No statistical difference among groups was observed for the bottom/top hardness ratio. Regarding the depth of cure, the CQ and those formulated with CQ associations presented higher values than TPO and BAPO. Regarding color, BAPO and CQ+BAPO presented the highest ΔE* after 30 days in water immersion, whereas CQ+TPO and CQ+TPO+BAPO presented the lowest after 30 days in coffee immersion. CONCLUSION: The associations CQ+TPO and CQ+TPO+BAPO presented improved color stability and hardness when compared with CQ, and did not influence the depth of cure. CLINICAL SIGNIFICANCE: The combination of alternative photoinitiators with the traditional camphorquinone/amine system improved the color stability of the model resin composites and maintaining their mechanical properties.

Bulk and surface properties related to composite filler size

There are few studies that fully characterize the effect of the filler size on the surface, optical and mechanical properties of resin composites. AIM: To determine the influence of the filler size content on surface, optical and mechanical properties before and after accelerated aging. METHODS: Seven resin composites were investigated: Filtek Supreme® (3M/ESPE), Estelite Σ Quick® (Tokuyama), Evolu-X® (Dentsply), Esthet-X HD® (Dentsply), Opallis® (FGM), Herculite XRV Ultra® (Kerr) and Filtek Z250® (3M/ESPE). Elastic modulus (EM) and flexural strength (FS) were determined by three-point bending of specimens immersed or not in absolute ethanol for seven days. Roughness (Ra) and gloss (G.U.) analyses were determined before and after ethanol storage for seven days and CIELAB color change (ΔE*) was obtained with a spectrophotometer. Results were analyzed by two-way ANOVA (general linear model) for EM and FS, with repeated measures for roughness and gloss, and one-way ANOVA for ΔE*. All comparisons were performed by Tukey's test (5%). Pearsons' correlation test was performed to determine the correlation between EM, FS, roughness, gloss, and ΔE* with the mean filler sizes. RESULTS: Mechanical properties decreased for all materials when submitted to immersion in ethanol. Increasing filler size gradually increased EM, FS and roughness values; gloss values decreased and didn't significantly affects ΔE*. Nanofiller composites presented higher gloss values than the others. CONCLUSIONS: It was possible to determine that the average filler size is a good predictor just for FS and gloss retention.

Avaliação da abrasividade de escovas dentais com cerdas macias / Abrasion assessment of soft bristle toothbrushes

Uma ampla variedade de escovas dentais está disponível no mercado com diversas indicações clínicas. Entretanto, poucos estudos na literatura avaliam a abrasão de escovas de diferentes marcas sobre as restaurações de resina composta. Objetivo: o presente estudo buscou avaliar a abrasividade de três escovas dentais com cerdas macias: Oral B Indicator Plus®, Colgate Extra Clean® e Dr. Veit Soft® em um compósito restaurador. Materiais e método: discos do compósito (8 mm x 2 mm) Tetric Ceram® foram produzidos e fotoativados com uma fonte de luz LED por 40 segundos cada. Dezoito amostras foram confeccionadas e divididas em três grupos experimentais (n = 6). Foram avaliadas a rugosidade superficial (Ra) e a massa em gramas (g) de cada espécime. Em seguida, os espécimes e as escovas foram posicionados em uma máquina simuladora de escovação (ODEME®, Luzerna, SC, Brasil). Os grupos foram submetidos a ciclos que simularam o uso contínuo das escovas por 3 meses. Para cada amostra, foi preparada uma pasta contendo a proporção em massa 1:2 de água destilada e pasta dental. Após a abrasão, a rugosidade e massa foram novamente mensuradas. As extremidades das cerdas foram observadas em um estereomicroscópio com magnitude de 45x. Os resultados foram submetidos ao teste estatístico de Análise de Variância com medidas repetidas no tempo (5%). Resultados: Não houve diferença estatística em massa para nenhum grupo antes e após abrasão (p = 0,727). No entanto, as escovas Oral B Indicator Plus® e Colgate Extra Clean® produziram superfícies mais rugosas (p = 0,002) quando comparada com Dr. Veit Soft® após abrasão. Conclusão: os resultados mostraram que existe variação no potencial de abrasão de escovas dentais classificadas comercialmente como cerdas macias de diferentes fabricantes.

There is a wide variety of toothbrushes available in the market with various clinical indications. However, there are few studies in literature that assess the abrasion of toothbrushes of different brands on composite resin restorations. Objective: the present study assessed the abrasion of three brands of soft bristles toothbrushes: Oral B Indicator Plus™, Colgate Extra Clean™, and Dr. Veit Soft™ on a restorative composite material. Materials and method: discs of composite material (8 mm x 2 mm) Tetric Ceram™ were produced and light cured with an LED unit for 40 seconds each. A total of 18 samples were made and divided in three experimental groups (n = 6). Superficial roughness (Ra) and mass in grams (g) of each sample were assessed. Then, the samples and toothbrushes were placed in a toothbrushing simulating machine (ODEME™, Luzerna, SC - Brazil). The groups were submitted to cycles simulating the continuous use of toothbrushes for 3 months. A paste containing the proportion in mass 1:2 of distilled water and dental paste was prepared for each sample. After abrasion, roughness and mass were measured again. The ends of the bristles were observed with a stereomicroscope at 45x magnitude. The results were submitted to ANOVA test with repeated measures over time (5%). Results: there was no statistical difference in mass for any group before and after toothbrush abrasion (p = 0.727). However, Oral B Indicator Plus and Colgate Extra Clean toothbrushes produced rougher surfaces (p = 0.002) than Dr. Veit Soft after abrasion. Conclusion: the results showed that there are variations in the potential for abrasion of toothbrushes commercially classified as soft bristles from different manufacturers.

The influence of nanoscale inorganic content over optical and surface properties of model composites.

OBJECTIVES: To investigate the influence of nanoscale inorganic content over optical and surface properties of model composites before and after ageing. METHODS: Three model composites were formulated with silica fillers in nanoscale of 7 nm (G1), 12 nm (G2) and 16 nm (G3), at 45.5% by weight in a matrix of BisGMA/TEGDMA 1:1. Color coordinates (CIE L*a*b* parameters), color difference (ΔE*), translucency parameter (TP), surface gloss (SG) and surface roughness (SR) were measured before and after ageing procedures of immersion in water and toothbrush abrasion. Surface hardness (SH) were evaluated before and after immersion in absolute ethanol. Results were submitted to two-way ANOVA followed by Tukey's post hoc test performed at a pre-set alpha of 0.05. RESULTS: Regarding CIE L*a*b* parameters, a darkening, a redness and a blueness effect, were respectively detected after water storage for all groups. Smaller filler sizes (G1) had the highest CIE b* values, whereas medium (G2) (p<0.05) had higher values than larger fillers (G3) (p<0.05) either before or after water immersion. Toothbrush abrasion did not produce any significant effect on CIE a* and CIE b* values, however increased CIE L*, decreased TP in addition to produce rougher and matte surfaces in all groups. Filler size did not influence ΔE* (p>0.05), although a tendency towards lower values in smaller filler materials was observed. Ageing after immersion in absolute ethanol decreased SH for all model composites. CONCLUSIONS: Filler sizes and ageing procedures influenced the optical and surface properties of the nanostructured composites evaluated in this study. CLINICAL SIGNIFICANCE: Filler size influenced optical and surface properties of resin composites. Materials containing smaller filler size offered improved optical stability and surface properties that can lead to longer maintenance of the restoration's appearance in the oral environment.

Associação de compostos fluoretados no tratamento de lesões incipentes de cárie / The association of fluoride in the treatment of incipient caries lesions

A doença cárie, quando diagnosticada em seu estágio inicial, é passível de ser tratada de forma não invasiva através de agentes remineralizadores, como os fluoretos. Dentre os compostos fluoretados, destaca-se o dentifrício, que é o que apresenta o melhor custo benefício, devido à praticidade, baixo custo e freqüência de aplicações. Porém, em pacientes de alto risco e/ou de atividade de cárie, a associação de produtos fluoretados pode trazer benefícios adicionais. Neste sentido, o objetivo do presente estudo foi realizar um levantamento da literatura sobre as vantagens e desvantagens da associação de produtos fluoretados no tratamento remineralizador de lesões incipientes de cáries.

Banco de dentes humanos na percepção dos acadêmicos da faculdade de odontologia da Universidade Federal Fluminense / Dentistry students' knowledge about the human tooth bank of Universidade Federal Fluminense

O objetivo desta pesquisa foi avaliar o nível de informação dos alunos dos 4º, 5º e 6º períodos da Faculdade de Odontologia da Universidade Federal Fluminense (FO-UFF) acerca da importância do Banco de Dentes Humanos (BDH) e sua funcionalidade. Foram entrevistados 95 alunos, utilizando questionário com perguntas fechadas. Os resultados indicaram que 100% dos alunos tem consciência da existência do BDH na FO-UFF e que 71,3% tem conhecimento de sua finalidade. Esse conhecimento é diferenciado em função do período que o aluno esteja cursando (x2), sendo a proporção de alunos do 4º período significativamente menor (p<0,05). Os autores concluíra, que há necessidade de um maior trabalho de divulgação na população de alunos estudada sobre a importância do BDH.

This research’s goal was to evaluate the level of information known by the 4th, 5th and 6th terms’ students from the Dental School at Universidade Federal Fluminense (FO-UFF) about the importance of the Human Teeth Bank (BDH) and its functionality. There were 95 students in the research, and it was used an objective assessment. The results indicated that 100% of the students know about UFF´s Dental School teeth bank, and that 71,3% knowm it’s purpose. This knowledge depends on the term the student’s on (x2), and the proportion of students who are on their 4th term is highly smaller (p<0,05). The authors concluded that there’s a need to inform more the 4th, 5th and 6th terms’ students about the importance of BDH.