Influence of photoactivation method and mold for restoration on the Knoop hardness of resin composite restorations.

The aim of this study was to evaluate in vitro the Knoop hardness in the top and bottom of composite photo activated by different methods when different mold materials were used. Z250 (3M ESPE) and XL2500 halogen unit (3M ESPE) were used. For hardness test, conical restorations were made in extracted bovine incisors (tooth mold) and also metal mold (approximately 2 mm top diameter × 1.5 mm bottom diameter × 2 mm in height). Different photoactivation methods were tested: high-intensity continuous (HIC), low-intensity continuous (LIC), soft-start, or pulse-delay (PD), with constant radiant exposure. Knoop readings were performed on top and bottom restoration surfaces. Data were submitted to two-way ANOVA and Tukey's test (p = 0.05). On the top, regardless of the mold used, no significant difference in the Knoop hardness (Knoop hardness number, in kilograms-force per square millimeter) was observed between the photoactivation methods. On the bottom surface, the photoactivation method HIC shows higher means of hardness than LIC when tooth and metal were used. Significant differences of hardness on the top and in the bottom were detected between tooth and metal. The photoactivation method LIC and the material mold can interfere in the hardness values of composite restorations.

Influence of Different Concentration and Ratio of a Photoinitiator System on the Properties of Experimental Resin Composites.

The aim in this study was to evaluate the influence of different ratio of camphorquinone/tertiary amine concentration on the flexural strength (FS), elastic modulus (EM), degree of conversion (DC), yellowing (YL), water sorption (WS) and water solubility (WSL) of experimental composites. Thus, acrylate blends were prepared with different camphorquinone (CQ) and amine (DABE) concentrations and ratios by weight: (CQ/DABE%): 0.4/0.4% (C1), 0.4/0.8% (C2), 0.6/0.6% (C3), 0.6/1.2% (C4), 0.8/0.8% (C5), 0.8/1.6% (C6), 1.0/1.0% (C7), 1.0/2.0% (C8), 1.5/1.5% (C9), 1.5/3.0% (C10). For the FS and EM, rectangular specimens (7x2x1 mm, n=10) were photo-activated by single-peak LED for 20 s and tested at Instron (0.5 mm/min). Then, the same specimens were evaluated by FTIR for DC measurement. For YL, disks (5x2 mm, n=10) were prepared, light-cured for 20 s and evaluated in spectrophotometer using the b aspect of the CIEL*a*b* system. For WS and WSL, the volume of the samples was calculated (mm³). For WS and WSL, composites disks (5x0.5 mm, n=5) were prepared. After desiccation, the specimens were stored in distilled water for 7 days and again desiccated, in order to measure the WS and WSL. Data were submitted to one-way ANOVA and Tukey's test (5%). The groups C8, C9 and C10 showed higher DC, EM and YL means, compared to other composites. Therefore, the FS and WS values were similar among all groups. Also, C1, C2 and C3 presented higher WSL in 7 days, compared to other composites. In general, higher concentrations of camphorquinone promoted higher physical-mechanical properties; however, inducing higher yellowing effect for the experimental composites.

Effect of monomer blend and chlorhexidine-adding on physical, mechanical and biological properties of experimental infiltrants.

OBJECTIVES: The aim of the study was to evaluate antimicrobial inhibition zone, degree of conversion (DC) and Knoop hardness (KH) of experimental infiltrants. Experimental low viscosity monomer blends were prepared and chlorhexidine diacetate salt (CHX) (0.1% or 0.2%) was added comprising the groups: G1) TEGDMA; G2) TEGDMA/0.1CHX; G3) TEGDMA/0.2CHX; G4) TEGDMA/UDMA; G5) TEGDMA/UDMA/0.1CHX; G6) TEGDMA/UDMA/0.2CHX; G7) TEGDMA/BISEMA; G8) TEGDMA/BISEMA/0.1CHX; G9) TEGDMA/BISEMA/0.2CHX. Icon® was used as control group. METHODS: Specimens of resin blends were made (n=9) to accomplished DC and KH. Pour plate was accomplished to evaluate antimicrobial groups' activity against Streptococcus mutans (SM) and Lactobacillus acidophilus (LA). Data obtained were submitted to two-way ANOVA and Tukey tests for blends comparisons and Dunnett's test for comparisons between experimental infiltrants and Icon® (p<0.05). RESULTS: In relation to antimicrobial effect, uncured blends showed higher antibacterial activity than cured ones for the most of blends. After polymerization, G5 showed the highest inhibition zone against SM and, G3 and G6 against LA. Concerning KH, TEGDMA/UDMA-based blends showed the highest values of KH number and it was influenced by monomeric base, regardless CHX concentration. DC was not affected by monomer blend composition, neither for CHX concentration. The antimicrobial activity was affected by monomeric base, CHX concentration and polymerization. Experimental infiltrants presented similar or higher performance than Icon® for the properties evaluated. SIGNIFICANCE: White spot lesion infiltration with low viscosity monomer blends (infiltrants) is an alternative to stop initial caries lesions progression. The incorporation of an antimicrobial agent as chlorhexidine diacetate salt in infiltrants composition could enhance the performance of these materials.

Dynamic mechanical thermal analysis of composite resins with CQ and PPD as photo-initiators photoactivated by QTH and LED units.

OBJECTIVES: The aim of this study was to evaluate the thermal and mechanical properties of the composite resins containing the photo-initiators camphorquinone (CQ) and/or phenyl-propanodione (PPD) when photoactivated with halogen lamp (XL2500/3M-ESPE), monowave (UltraBlueIS/DMC) and polywave (UltraLume5/Ultradent) LED units. MATERIALS AND METHODS: A blend of BisGMA, UDMA, BisEMA and TEGDMA was prepared with the same wt% of photo-initiators CQ and/or PPD and 65wt% of silaneted filler particles. Compression strength (CS), diametral tensile strength (DTS) and diametral modulus (DM) were tested. Thermogravimetric analysis (TGA) was made and the lost residual monomer were verified. Dynamic mechanical thermal analysis (DMTA) was used for to analyze the glass transition temperature (Tg) and the storage modulus in 37°C. Degree of conversion (DC) was accomplished in the same samples of DMA using middle-infrared spectroscopy (mid-IR). RESULTS: CQ, CQ/PPD and PPD obtained the same results for all mechanical properties (CS, DTS and DM), lost residual monomer and storage modulus in 37°C, regardless LCU used. The results of Tg showed that the combination PPD-UltraLume5 produced the highest values. DC showed that the combination CQ-UltraLume5 resulted in the highest values and PPD-XL2500 in the lowest DC values. CONCLUSION: The study shows that PPD is not only effective photosensitizers, but also photocrosslinking agents for dental composite resins with a similar efficiency to CQ.

Polymerization capability of simplified dental adhesives with camphorquinone, phenyl-propanedione and bis-alkyl phosphine photoinitiators

Aim: this study aimed to evaluate the degree of conversion (DC) exhibited by novel formulations of dental adhesive systems including camphorquinone (CQ), phenyl-propanedione (PPD), and bis-alkyl phosphine oxide (BAPO) when cured by mono- or polywave light emitting diodes (LEDs). Methods: an adhesive model was formulated by mixing hydroxyethyl methacrylate (HEMA, 40 wt%) and bisphenol A glycidyl dimethacrylate (BisGMA, 60 wt%) in ethanol (30 wt%). Five materials were then formulated by adding the following photoinitiators: CQ (1 mol%), CQ/PPD (0.5/0.5 mol%), CQ/BAPO (0.5/0.5 mol%), PPD (1 mol%), and BAPO (1 mol%). The DC for each material was measured with Fourier transform infrared spectroscopy. Analysis of variance and Tukey's post-hoc test were used to analyze the data (p < 0.05). Results: Except for CQ, the photoinitiators provided a significantly higher DC in the adhesive systems following photoactivation with a polywave LED. Conclusion: The use of alternative photoinitiators and a polywave LED improved the DC of the adhesive systems examined

Influence of Different Concentration and Ratio of a Photoinitiator System on the Properties of Experimental Resin Composites

Abstract The aim in this study was to evaluate the influence of different ratio of camphorquinone/tertiary amine concentration on the flexural strength (FS), elastic modulus (EM), degree of conversion (DC), yellowing (YL), water sorption (WS) and water solubility (WSL) of experimental composites. Thus, acrylate blends were prepared with different camphorquinone (CQ) and amine (DABE) concentrations and ratios by weight: (CQ/DABE%): 0.4/0.4% (C1), 0.4/0.8% (C2), 0.6/0.6% (C3), 0.6/1.2% (C4), 0.8/0.8% (C5), 0.8/1.6% (C6), 1.0/1.0% (C7), 1.0/2.0% (C8), 1.5/1.5% (C9), 1.5/3.0% (C10). For the FS and EM, rectangular specimens (7x2x1 mm, n=10) were photo-activated by single-peak LED for 20 s and tested at Instron (0.5 mm/min). Then, the same specimens were evaluated by FTIR for DC measurement. For YL, disks (5x2 mm, n=10) were prepared, light-cured for 20 s and evaluated in spectrophotometer using the b aspect of the CIEL*a*b* system. For WS and WSL, the volume of the samples was calculated (mm³). For WS and WSL, composites disks (5x0.5 mm, n=5) were prepared. After desiccation, the specimens were stored in distilled water for 7 days and again desiccated, in order to measure the WS and WSL. Data were submitted to one-way ANOVA and Tukey's test (5%). The groups C8, C9 and C10 showed higher DC, EM and YL means, compared to other composites. Therefore, the FS and WS values were similar among all groups. Also, C1, C2 and C3 presented higher WSL in 7 days, compared to other composites. In general, higher concentrations of camphorquinone promoted higher physical-mechanical properties; however, inducing higher yellowing effect for the experimental composites

Resumo O objetivo foi avaliar a influência da concentração e proporção de canforoquinona (CQ)/amina terciária (DABE) na resistência à flexão (RF), módulo flexural (MF), grau de conversão (GC), amarelamento (AM), sorpção (SA) e solubilidade em água (SL) de compósitos experimentais. Blendas acrilatas foram preparadas com diferentes concentrações e proporções de CQ/DABE em peso, como segue: (CQ/DABE%): 0,4/0,4% (C1); 0,4/0,8% (C2); 0,6/0,6% (C3); 0,6/1,2% (C4); 0,8/0,8% (C5); 0,8/1,6% (C6); 1,0/1,0% (C7); 1,0/2,0% (C8); 1,5/1,5% (C9); 1,5/3,0% (C10). Para RF e MF, espécimes retangulares (7x2x1 mm, n=10) foram fotoativados com LED de pico único (Radii Cal) por 20 s e testados em máquina Instron (0,5 mm/min). Após, o GC dos mesmos espécimes (fragmentos) foi mensurado por FTIR. Para AM, discos de compósito (5x2 mm, n=10) foram preparados, fotoativados por 20 s e imediatamente avaliados em espectrofotômetro, considerando o aspecto b do sistema CIEL*a*b*. Para SA e SL, discos de compósito (5x0,5 mm, n=5) foram preparados e seus volumes calculados (mm³). Após desidratação, as amostras foram pesadas e armazenadas em água destilada por 7 dias, pesadas e novamente desidratadas e pesadas, para se calcular o SA e SL. Os dados foram submetidos a one-way ANOVA e teste de Tukey (5%). Os grupos C8, C9 e C10 mostraram maior GC, MF e AM, comparado aos outros grupos. No entanto, RF e SA foram similares entre todos os grupos. Ainda, C1, C2 e C3 apresentaram maior SL em 7 dias comparado aos outros grupos. Em geral, maiores concentrações de CQ promoveram melhores propriedades físico-mecânicas; no entanto, levaram ao maior amarelamento dos compósitos.

Influence of the curing method on the post-polymerization shrinkage stress of a composite resin.

The aim of this study was to evaluate the effect of different curing methods on the stress generated by the polymerization shrinkage of a restorative composite in two moments: immediately after light exposure and after 5 min. Photoactivation was performed using two different light sources: (1) xenon plasma arc (PAC) light (1,500 mW/cm2 - 3s) and (2) a quartz-tungsten-halogen (QTH) light with three light-curing regimens: continuous exposure (40 s at 800 mW/cm2 - CL); soft-start (10 s at 150 mW/cm2 and 30 s at 800 mW/cm2 - SS) and intermittent light [cycles of 4 s (2 s with light on at 600 mW/cm2 and 2 s of light off), for 80s - IL]. The composite resin was applied between two 5-mm diameter metallic rods, mounted in a servohydraulic machine. The maximum stress was recorded immediately after light exposure (FF) and after 5 min (5F). The results were submitted to ANOVA and Tukey's test (5%). For each method, the results obtained in FF and 5F were, respectively: CL (3.58 and 4.46 MPa); SS (2.99 and 4.36 MPa); IL (3.11 and 4.32 MPa) and PAC (0.72 and 3.27 MPa). The stress generated by the polymerization shrinkage during light exposure can be associated with the photoactivation method used. A significant increase in the stress level was observed during the post-curing period up to 5 min, for all evaluated methods.

Displasia cemento-óssea florida: relato de caso / Florid cemento-osseous dysplasia: case report

A displasia cemento-óssea florida (DCOF) é uma entidade incomum, benigna, frequentemente assintomátíca, limitada aos ossos gnáticos e acomete frequentemente mulheres negras acima de 40 anos. Nos casos com sintomatologia dolorosa, há uma associação com osteomielite crônica, provavelmente decorrente de infecçãso secundária. Esse tipo de lesão possui aspectos radiográficos e histopatológicos encontrados em outras patologias, como osteomielite esclerosante difusa e doença de Paget do osso. O objetivo desse estudo foi revisar a literatura acerca desta lesão, além de relatar um caso clínico de DCOF associada à osteomielite crônica. O exame clínico-anamnésico realizado com destreza, associado aos métodos complementares imagenológicos traz informações importantes para o diagnóstico dessa patologia, modulando os cuidados com os procedimentos cirúrgicos que muitas vezes são necessários para a terapêutica das complicações infecciosas. Por outro lado, procedimentos como exodontias, podem vir a favorecê-las, agravando assim, o quadro clínico do paciente.

Florid cemento-osseous dysplasia (FCOD) is an uncommon benign entity, frequently without painful sintomatology, limited to gnatic bones and occurs frequently in black women, above of 40 years. In cases with painful sintomatology, it has an association with chronic osteomielitis, probably decurrent of secondary infection. This kind of lesion has radiographic and histopathologic aspects found in others pathologies, as diffuse esclerosant osteomielitis and Paget's disease of the bone. The aim of this study was to revise the literature about this lesion, and report a clinical case of FCOD associated with chronic osteomielitis. Physical-anamnesic examination carried through with dexterity, associated to imagenologic complementary methods can bring important information for the diagnosis of this pathology, modulating the cares with the surgical procedures that many times are necessary for the therapeutics of the infectious complications. On the other hand, procedures as exodonties, can come to favor them, thus aggravating, the clinical aspects of the patient.

Influence of the curing method on the post-polymerization shrinkage stress of a composite resin

The aim of this study was to evaluate the effect of different curing methods on the stress generated by the polymerization shrinkage of a restorative composite in two moments: immediately after light exposure and after 5 min. Photoactivation was performed using two different light sources: (1) xenon plasma arc (PAC) light (1,500 mW/cm2 - 3s) and (2) a quartz-tungsten-halogen (QTH) light with three light-curing regimens: continuous exposure (40 s at 800 mW/cm2 - CL); soft-start (10 s at 150 mW/cm2 and 30 s at 800 mW/cm2 - SS) and intermittent light [cycles of 4 s (2 s with light on at 600 mW/cm2 and 2 s of light off), for 80s - IL]. The composite resin was applied between two 5-mm diameter metallic rods, mounted in a servohydraulic machine. The maximum stress was recorded immediately after light exposure (FF) and after 5 min (5F). The results were submitted to ANOVA and Tukey's test (5 percent). For each method, the results obtained in FF and 5F were, respectively: CL (3.58 and 4.46 MPa); SS (2.99 and 4.36 MPa); IL (3.11 and 4.32 MPa) and PAC (0.72 and 3.27 MPa). The stress generated by the polymerization shrinkage during light exposure can be associated with the photoactivation method used. A significant increase in the stress level was observed during the post-curing period up to 5 min, for all evaluated methods.

Uso de princípios de ilusão óptica no contorno cosmético: previsibilidade e excelência estética / Using principles of optical illusion for cosmetic recontouring: predictability and esthetic excellence

O contorno cosmético é uma técnica operatória que requer do profissional amplo conhecimento de estética e reflexão da luz, pois implica desgaste irreversível da estrutura dental sadia. Este artigo relata um caso clínico de contorno cosmético que ilustra as possibilidades de remodelação estética do sorriso guiadas por princípios de ilusão de óptica, na qual foi possível, mediante a realização de desgastes em esmalte, obter resultados satisfatórios com previsibilidade.

Cosmetic recontouring is a technique that demands comprehensive skills and knowledge about esthetics light dynamics by the professional, since irreversible reduction of tooth sound structure is required. This paper is a case report of the cosmetic contouring showing the possibilities of esthetic recontouring of the smile following principles of optical illusion, from which it was possible through enamel reduction to achieve satisfactory, predictable results.

Análise crítica dos métodos utilizados para determinar o surto de crescimento puberal pelos especialistas em ortodontia / Critical analysis of the used methods occasion to determine it of puberal growth for the specialists in orthodontics

Avaliar o surto de crescimento puberal (SCP) é importante na prática clínica ortodôntica, visto que o crescimento corporal que acontece nessa fase pode atuar como um excelente coadjuvante no tratamento. Esse estudo se propôs a analisar quais e como os métodos são utilizados pelos especialistas em ortodontia, da cidade de Salvador (Bahia), para avaliar o SCP. Foram enviados questionários com perguntas fechadas e abertas a todos os dentistas registrados no CROBA como especialistas em ortodontia. O universo foi composto de 90 ortodontistas e, desses, 67 responderam o questionário, constituindo uma amostra em que 64,1% dos informantes pertenciam ao sexo feminino. Os resultados mostram que todos os entrevistados concordaram ser necessário verificar o SCP e, desses, 94% indicaram seu uso para casos específicos como: pacientes em crescimento, distúrbios de crescimento ósseo, tratamento ortocirúrgico e (ou) ortopédicos, casos limítrofes, dúvidas sobre o estágio de desenvolvimento. Quanto ao método utilizado, houve uma predominância da análise carpal, seguida da análise das vértebras cervicais, dental e caracteres sexuais secundários. Nenhum dos entrevistados vinculou o SCP apenas à idade cronológica. Entretanto, quando solicitados a listar nomes dos métodos preferidos e dificuldades encontradas, foi grande o número de entrevistados que deixou de responder as perguntas. Tal fato faz concluir ser necessária uma maior divulgação dos métodos de análise do SCP, principalmente da análise das vértebras cervicais, que é o mais recente.