Ultrathin CAD-CAM glass-ceramic and composite resin occlusal veneers for the treatment of severe dental erosion: An up to 3-year randomized clinical trial.

STATEMENT OF PROBLEM: Ultrathin bonded posterior occlusal veneers represent a conservative alternative to traditional onlays and complete coverage crowns for the treatment of erosive dental wear. Data regarding the clinical performance of ceramic and composite resin ultrathin occlusal veneers are lacking. PURPOSE: The purpose of this prospective randomized clinical trial was to evaluate the influence of computer-aided design and computer-aided manufacturing (CAD-CAM) restorative material (ceramic versus composite resin) on the clinical performance of ultrathin occlusal veneers bonded to worn posterior teeth. MATERIAL AND METHODS: Eleven participants (mean age, 30.4 years) had their posterior teeth restored with 24 ceramic (e.max CAD) and 36 composite resin (Lava Ultimate) ultrathin occlusal veneers. The material type was assigned randomly. The tooth preparations were trial restoration driven and included immediate dentin sealing (OptiBond FL). The intaglio surfaces of the ceramic restorations were etched with hydrofluoric acid and silanated, and the composite resins were airborne-particle abraded and silanated. The tooth preparations were airborne-particle abraded and etched with phosphoric acid before restoration insertion. All restorations were adhesively luted with preheated composite resin (Filtek Z100). The participants were evaluated according to the modified United States Public Health Service (USPHS) criteria at baseline and then each year for up to 3 years. Survival rates were estimated with time to failure (primary outcome of interest) as the endpoint (scores 4 or 5). RESULTS: No restorations were lost. Five partial failures, in the form of chipping (all scored 4), were observed in the composite resin group (Lava Ultimate). The Kaplan-Meier survival rates were 100% for ceramic and 84.7% (SE 0.065%) for composite resin. Differences between the 2 groups were not statistically significant (P=.124). In the surviving restorations, significant difference (P=.003) was found for surface roughness as restorations in the composite resin group experienced some surface degradation. CONCLUSIONS: The findings of this medium-term clinical trial suggest that ceramic (e.max CAD) and composite resin (Lava Ultimate) CAD-CAM ultrathin occlusal veneers presented statistically comparable performance regardless of the minor partial failures (restorable chipping) observed in the composite resin group. Higher surface degradation was observed in the composite resin group.

LED Colour Trap for Aedes aegypti Control.

BACKGROUND: Aedes aegypti mosquitoes transmit dengue, zika, and chikungunya viruses, neglected diseases that are considered global health challenges. Due to the lack of antiviral drugs and vaccines for these illnesses, vector control with chemical insecticides is the principal strategy for preventing their spread. However, vector populations are becoming increasingly resistant to insecticides, and the development of other control measures is, therefore, imperative. METHODS: A new insect trap (IT) was used to control Aedes aegypti. A specific light-emitting diode (LED) served as the attractant based on specific wavelength ranges (450-495, 500-550 and 570-600 nm). The IT utilized insect-attracting and killing mechanisms that included a black capture box, a suction-producing mechanism, an electric shock device and a nylon cloth device that held surviving mosquitoes, which died due to starvation. Capture assays of twenty non-feeding females inside a cage were performed in triplicate using different LED intensities. A commercial trap (ultraviolet lamp attractant and suction system) was used as a positive control. RESULTS: Capture assays of A. aegypti with different intensities and LED combinations showed that the tricolored trap captured 100% of the females, followed by the Green LED 8 set, which captured 91%; in comparison, commercial traps captured approximately 25% of the insects. Although there were no significant differences between the experimental groups, the tricolored trap probably will capture more mosquito females considering the vision variation in individual females. CONCLUSION: We herein present a green technology-based IT that is effective, safe and successful for reducing mosquito populations, thereby preventing mosquito-borne disease spread.

Influence of adhesive strategy on clinical parameters in cervical restorations: A systematic review and meta-analysis.

OBJECTIVES: We aimed to answer the following PICO question: "Is the risk of postoperative sensitivity (POS), retention rates and marginal discoloration of composite restorations [CR] bonded with self-etch (SE) in non-carious cervical lesions (NCCLs) of adults equals to etch-and-rinse (ER) adhesives?". METHODS: A comprehensive search was performed in May 2016 in the MEDLINE, Scopus, Web of Science, LILACS, BBO and Cochrane Library and SIGLE, abstracts of IADR, unpublished and ongoing trials registries, dissertations and theses without restrictions. Only randomized clinical trials that compared composite resin restorations placed with self-etch and etch-and-rinse in NCCLs were included. After removal of duplicates and non-eligible articles, 50 articles from 42 studies (follow-ups of the same study were merged) remained for synthesis of the risk of bias (Cochrane Risk of bias tool). RESULTS: Thirteen studies were at "high" risk of bias, yielding 29 studies for meta-analysis. No difference on the POS after restoration placement (risk ratio [RR] 1.04; 95% CI 0.81 to 1.34) as well as in the retention rates for all follow-up periods was observed. The etch-and-rinse approach produced less marginal discoloration at 18 months to 2 years (RR 1.51; 95% CI 1.21 to 1.90) and at 4 to 5 years (RR 1.81; 95% CI 1.28 to 2.55) (p<0.0007). CONCLUSIONS: The adhesive strategy did not influence the POS and the retention rates of composite resin in NCCLs in any of the follow-up periods; but less marginal discoloration was found in etch-and-rinse adhesives. CLINICAL SIGNIFICANCE: Composite resin restorations placed with self-etch and etch-and-rinse adhesives produce restoration with the similar clinical service and POS, however using etch-and-rinse adhesives one can reduce marginal discoloration. PROSPERO registration number: CRD42015019533.

The effect of combining photoinitiator systems on the color and curing profile of resin-based composites.

OBJECTIVE: To evaluate the effect of combining camphorquinone (CQ) and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) on the color and curing profile of resin-based composites. METHODS: Experimental composites were produced with different CQ and TPO molar concentrations: CQ-only, 3CQ:1TPO, 1CQ:1TPO, 1CQ:3TPO, and TPO-only. Polywave LED was characterized using a beam profiler. Block-shaped samples (5mm×5mm×3mm depth) were cured in a custom-designed mold with a polywave LED positioned to compare the regions exposed to the 420-495nm and 380-420nm LED emittances. To map the cure profile, degree of conversion (DC) of longitudinal cross-sections from each block were evaluated by FT-NIR. Color, light-transmittance and light-absorption during curing were evaluated on specimens 1-3mm thick. Data were analyzed using ANOVA/Tukey's test (α=0.05; ß=0.2). RESULTS: Though the polywave LED beam profile was non-uniform, up to a depth of 2mm no differences in DC were found among the composites containing CQ with TPO added up to 50%, regardless of the position under the curing tip. Composites with higher TPO concentration showed a decrease in DC beginning with a depth of 1mm, while composites with higher or similar CQ concentrations did not show decreased DC until a depth of 3mm. Higher TPO concentration reduced initial yellowness and color change after curing; and lower CQ concentration decreased light-absorption at greater depths. SIGNIFICANCE: The combination of CQ with TPO added up to 50% reduced the yellowness and color change of composites after curing without affecting cure efficiency up to a depth of 2mm.

Polymerization kinetics and reactivity of alternative initiators systems for use in light-activated dental resins.

OBJECTIVES: The purpose of this study was to evaluate the reactivity and polymerization kinetics behavior of a model dental adhesive resin with water-soluble initiator systems. METHODS: A monomer blend based on Bis-GMA, TEGDMA and HEMA was used as a model dental adhesive resin, which was polymerized using a thioxanthone type (QTX) as a photoinitiator. Binary and ternary photoinitiator systems were formulated using 1mol% of each initiator. The co-initiators used in this study were ethyl 4-dimethylaminobenzoate (EDAB), diphenyliodonium hexafluorophosphate (DPIHFP), 1,3-diethyl-2-thiobarbituric acid (BARB), p-toluenesulfinic acid and sodium salt hydrate (SULF). Absorption spectra of the initiators were measured using a UV-Vis spectrophotometer, and the photon absorption energy (PAE) was calculated. The binary system camphorquinone (CQ)/amine was used as a reference group (control). Twelve groups were tested in triplicate. Fourier-transform infrared spectroscopy (FTIR) was used to investigate the polymerization reaction during the photoactivation period to obtain the degree of conversion (DC) and maximum polymerization rate (R(p)(max)) profile of the model resin. RESULTS: In the analyzed absorption profiles, the absorption spectrum of QTX is almost entirely localized in the UV region, whereas that of CQ is in the visible range. With respect to binary systems, CQ+EDAB exhibited higher DC and R(p)(max) values. In formulations that contained ternary initiator systems, the group CQ+QTX+EDAB was the only one of the investigated experimental groups that exhibited an R(p)(max) value greater than that of CQ+EDAB. The groups QTX+EDAB+DPIHFP and QTX+DPIHFP+SULF exhibited values similar to those of CQ+EDAB with respect to the final DC; however, they also exhibited lower reactivity. SIGNIFICANCE: Water-soluble initiator systems should be considered as alternatives to the widely used CQ/amine system in dentin adhesive formulations.

Dureza de resinas compostas de diferentes cores, em profundidades distintas, fotoativadas por diferentes fotopolimerizadores / Hardness of composite resins of different colors, at distinc depths, photoactivated by different light-curing units

Objetivo: Avaliar a dureza de resinas compostas (RC) de cores diferentes em duas profundidades (topo e base), fotoativadas com diferentes fotopolimerizadores. Méto-do: Utilizaram-se duas RC de cores e opacidades diferentes (Filtek Supreme A1E®, Filtek Supreme A3D®) e quatro aparelhos fotopolimerizadores LED (Ultra Blue Is 600® - 450 mW/cm2; Optilight LD III® - 250 mW/cm2; Ultraled® - 250 mW/cm2; Radii® - 700 mW/cm2). Confeccionaram-se 24 matrizes de polímero de náilon (5 mm de diâmetro e 3 mm de espessura), nas quais as RC foram inseridas em dois incrementos de 1,5 mm cada, fotoativados por 20s cada. Submeteram-se os corpos-de-prova (cp) à análise de dureza Vickers no 'topo' e na 'base', com quatro medidas em cada superfície. A média de dureza de cada cp foi calculada e aplicaram-se análise de variância e Tukey. Resultados e conclusões: Observou-se que a dureza das RC variou conforme a cor do material e os aparelhos utilizados, com o Raddi e o Ultra Blue IS proporcionando os maiores valores. De forma geral, as RC apresentaram maior dureza no topo do que na base. Na base, a resina composta com maior translucidez apresentou maior dureza do que a resina composta opaca.

Efeito de dois selantes de superfície na alteração colorimétrica de uma resina composta / Effect of two surface sealants on color alteration of a composite resin

Objetivo: avaliar a variação de cor entre superfícies tratadas com agentes químicos de acabamento e polimento. Métodos: Foram utilizadas resina Fill Magic (Vigodent®, Rio de Janeiro, Brasil), A2 (n=18) e A3,5 (n=18). As amostras foram fotopolimerizadas, registrado os valores de L*a*b* através da análise em um colorímetro, posteriormente, foi aplicado uma camada de selantes de superfície, BisCoverTM LV (Bisco Inc, Schaumburg, USA) e Fill Glaze (Vigodent®, Rio de Janeiro, Brasil) e novamente averiguado os valores de L*a*b*. Para o grupo controle não houve tratamento, sendo registrado os valores de L*a*b* em dois tempos distintos. Os valores referentes a varialção de cor foram submetidos à análise de variância (ANOVA) e posteriormente ao teste de Tukey. Resultados: Não houve alteração colorimétrica utilizando o selante BisCoverTM LV sobre a resina A2 e A3,5 (p>0,05). Entretanto, houve alteração colorimétrica quando utilizado Fill Glaze sobre a resina A2 e A3,5 (P=0,0021 e p=0,0020, respectivamente). Conclusão: O selante de superfície BisCoverTM LV não apresentou alteração colorimétrica, sendo ideal para utilização em restaurações estéticas em que a cor da resina deve ser mantida.

Objective: To evaluate the alteration of color (DE) among surfaces treated with liquid finish and polish system. Method: Was used Fill Magic (Vigodent®, Rio de Janeiro, Brasil), A2 (n=18) and A3.5 (n=18) composite resins. The specimens were polymerized, and was registered L*a*b* values using a colorimeter, then two surface sealants was applied: BisCoverTM LV (Bisco Inc, Schaumburg, USA) and Fill Glaze (Vigodent®, Rio de Janeiro, Brazil) and was registered L*a*b* values. For the control group was not applied surface sealant, and L*a*b* values was registered in two different moments. The DEab* values were submitted to the analysis of variance (ANOVA) and then to the Tukey test. Results: Was not observed color alteration using BisCoverTM LV in both resins A2 and A3.5 (p>0.05). However, was observed color alteration when was used Fill Glaze, in both resins A2 and A3.5 (p=0.021 and p=0.002, respectively). Conclusion: In two tested composite resins colors, the surface sealant BisCoverTM LV presented no color alteration, ideal to application in esthetic restoration, when the color should be maintaining.

The initiating radical yields and the efficiency of polymerization for various dental photoinitiators excited by different light curing units.

OBJECTIVES: To evaluate the efficiency of the photopolymerization of dental resins it is necessary to know to what extent the light emitted by the light curing units is absorbed by the photoinitiators. On the other hand, the efficiency of the absorbed photons to produce species that launch the polymerization process is also of paramount importance. Therefore, the previously determined PAE (photon absorption efficiency) is used in conjunction with the polymerization quantum yields for the photoinitiators, in order to be able to compare the total process on an equivalent basis. This parameter can be used to identify the best performance for the photochemical process with specific photoinitiators. METHODS: The efficiency of LED (Ultrablue IS) and QTH (Optilux 401) lamps were tested comparing their performances with the photoinitiators camphorquinone (CQ); phenylpropanedione (PPD); monoacylphosphine oxide (Lucirin TPO); and bisacylphosphine oxide (Irgacure 819). The extent of photopolymerization per absorbed photon was determined from the polymerization quantum yields obtained by using the photoinitiators to polymerize methyl methacrylate, and afterwards combined with the previously determined PAEs. RESULTS: Although CQ presents a rather low polymerization quantum yield, its photopolymerization efficiency is practically the highest when irradiated with the Ultrablue LED. On the other hand, Lucirin is much more efficient than the other photoinitiators when irradiated with a QTH lamp, due to its high quantum yield and the overlap between its absorption spectrum and the output of the visible lamp light. SIGNIFICANCE: Difference in photopolymerization efficiencies arise when combinations of photoinitiators are used, and when LED sources are used in preference to QTH. Mechanistic understanding is essential to optimal initiator formulation.

The effect of specimen dimensions on the flexural strength of a composite resin

OBJETIVO: A finalidade da presente investigacão foi avaliar a influência das dimensões dos corpos-de-prova (cp) e da superfície de irradiacão na resistência à flexão de uma resina composta (Heliomolar RO). MÉTODOS: As diversas dimensões adotadas - comprimento x largura x altura (mm) foram: 25x2x4; 25x2x2 (ISO 4049); 15x2x2; 10x2x2; 10x2x1. A fotoativacão foi realizada por 40 segundos a 600mW/cm2; três vezes ao longo dos cp de 25mm, duas vezes ao longo dos cp de 15mm e uma vez nos cp de 10mm de comprimento. Os corpos-de-prova de todas as dimensões foram ativados em ambas as superfícies, ou apenas em uma; neste caso a carga de ruptura era aplicada na face de irradiacão ou na oposta. RESULTADOS: Foi mostrado que a resistência à flexão não foi afetada pelo comprimento dos cp. Com a fotoativacão em ambas as superfícies, as resistências obtidas eram semelhantes nos diversos comprimentos. Independentemente do número de faces irradiadas, os cp com 1mm de altura apresentaram resistências semelhantes. Contudo, cp com 4mm de altura e irradiados apenas por um lado, alcancaram os menores valores. CONCLUSAO: Com o emprego de cp com dimensões menores são alcancados valores de resistência à flexão semelhante aos obtidos com cp padronizados (ISO 4049), com a vantagem de menor demanda de material e menor consumo de tempo (o menor comprimento dos cp requer apenas uma ativacão por lado).

Molar extinction coefficients and the photon absorption efficiency of dental photoinitiators and light curing units.

OBJECTIVES: The light absorption of dental photoinitiators should correlate with the spectral emission profiles of dental light curing units compared on an equivalent basis. Spectral data of dental photoinitiators and light curing units can be used to define the photon absorption efficiency (PAE) obtained by integrating the product of the absorption and emission spectra in terms of photons. This parameter can be used to identify the best performance for photochemical process with specific photoinitiators. METHODS: The efficiency of two LED and one QTH lamps were tested comparing their performances with the photoinitiators camphorquinone (CQ); phenylpropanedione (PPD); monoacylphosphine oxide (Lucirin TPO); and bisacylphosphine oxide (Irgacure 819). Absorption and emission spectra of the photoinitiators and the LED (Ultrablue I and Ultrablue IS) and QTH (Optilux 401) LCUs were determined in the 360-550nm range. RESULTS: CQ exhibited an absorption centered in the blue region and, although the maxima of PPD, MAPO, and BAPO were in the UV-A region, their absorption extended to the visible region. Power output maxima of the LCUs were at 467 (Ultrablue I), 454 (Ultrablue IS) and 493nm (Optilux 401), and the total power densities were 170+/-1, 470+/-4 and 444+/-4mW/cm(2), respectively. SIGNIFICANCE: The use of the PAE allows a prediction of the most efficient photoinitiator/LCU systems. For similar photoinitiator concentrations, Lucirin and CQ are most efficiently photoinitiated by the QTH unit, whereas the high-power LED device is more efficient for Irgacure. PPD is photoactivated similarly by both LCUs.

The effect of specimen dimensions on the flexural strength of a composite resin.

UNLABELLED: PUORPOSE: The aim of this study was to evaluate the effect of specimen dimensions on the flexural strength of a composite resin (Heliomolar RO). METHODS: The different dimensions tested - length x width x height (mm) were: 25x2x4; 25x2x2 (ISO 4049); 15x2x2; 10x2x2 and 10x2x1. Light-curing was performed at 600 mW/cm² for 40s, three times along the 25mm specimens, twice along 15mm specimen and once for the 10mm specimens. Specimens of all dimensions were light-cured on both surfaces, or only on one side. In the latter, the load was applied on the irradiated side or on the opposite one. RESULTS: It was shown that the flexural strength was not affected by specimen length. When light-curing was performed on both surfaces, similar flexural strength values were obtained for any dimension. Despite the number of irradiated surfaces, specimens with a height of 1mm also obtained similar values. On the contrary, specimens with a height of 4mm, exposed only on one surface, reached the lowest strength. CONCLUSION: The use of specimens with lower dimensions can lead to flexural strength values similar to the ones obtained with standardized specimen (ISO 4049), with the advantage of demanding less amount of material and being less time consuming.

Análise do grau de conversäo de uma resina experimental fotopolimerizável: um estudo espectrométrico em funçäo de diferentes fotoiniciadores e fontes de luz / Degree of conversion of an experimental light-cured resin? a spectrometric study related to different photoinitiators and light sources

O objetivo deste estudo foi avaliar o grau de conversäo de uma resina fotopolimerizável experimental (BisGMABisEMAUDMATEGDMA). Os fatores estudados foram: Fotoiniciadores incorporados à resina - I) Lucirin TPO+CanforquinonaAmina, II) PPD+CanforquinonaAmina, III) Irgacure 819+CanforquinonaAmina, IV) CanforquinonaAmina, V) Lucirin TPO, VI) PPD, VII) Irgacure 819; Fontes de luz - Optilux 401 (Halógena), Ultrablue I (LED); Ultrablue IS (LED). Diferentes sistemas de fotoiniciaçäo foram adicionados à resina nas seguintes concentraçöes, em peso, - Canforquinona (0,25 por cento), Amina (0,5 por cento) e demais fotoiniciadores (0,5 por cento). Uma gota de cada resina foi fotoativada com cada fonte de luz sob os seguintes tempos - 20s (Optilux 401), 50s (Ultrablue IS) e 18s (Ultrablue IS). Foram utilizados três corpos-de-prova para cada condiçäo experimental (n=63), sendo o grau de conversäo obtido por meio da espectroscopia FT-Raman, na comparaçäo da altura dos sinais relativos à ligaçäo C=C aromática (`1609cm POT.-1`) e alifática (`1639cm POT.-1`), antes e após a fotoativaçäo. Os resultados permitiram concluir que; no grupo das resinas com Canforquinona e sem Canforquinona, os maiores valores ocorreram nas resinas com Irgacure 819, fotoativadas pelo Optilux 401 ou Ultrablue IS; o Ultrablue I mostrou-se ineficaz para a conversäo de resinas contendo apenas Lucirin TPO ou PPD, porém apresentou resultados similares na conversäo das resinas com Canforquinona