Converting a conventional wired‑halogen illuminated indirect ophthalmoscope to a wireless‑light emitting diode illuminated indirect ophthalmoscope in less than 1000/‑ rupees.

Aim: To report the “do it yourself” method of converting an existing wired‑halogen indirect ophthalmoscope (IO) to a wireless‑light emitting diode (LED) IO and report the preferences of the patients and the ophthalmologists. Subjects and Methods: In this prospective observational study, a conventional IO was converted to wireless‑LED IO using easily available, affordable electrical components. Conventional and the converted IO were then used to perform photo‑stress test and take the feedback of subjects and the ophthalmologists regarding its handling and illumination characteristics. Results: The cost of conversion to wireless‑LED was 815/‑ rupees. Twenty‑nine subjects, mean age 34.3 ± 10 years with normal eyes were recruited in the study. Between the two illumination systems, there was no statistical difference in the magnitude of the visual acuity loss and the time to recovery of acuity and the bleached vision on photo‑stress test, although the visual recovery was clinically faster with LED illumination. The heat sensation was more with halogen illumination than the LED (P = 0.009). The ophthalmologists rated wireless‑LED IO higher than wired‑halogen IO on the handling, examination comfort, patient’s visual comfort and quality of the image. Twenty‑two (81%) ophthalmologists wanted to change over to wireless‑LED IO. Conclusions: Converting to wireless‑LED IO is easy, cost‑effective and preferred over a wired‑halogen indirect ophthalmoscope.

Effect of light-curing units in shear bond strength of metallic brackets: an in vitro study

OBJECTIVES: To determine the influence of the light curing units on the shear bond strength of orthodontic brackets. MATERIAL AND METHODS: Seventy-two premolars were divided into six groups (n=12): Group I: brackets bonded with Transbond and polymerization with halogen light; Group II: Transbond and LED; Group III: Fuji Ortho and halogen light; Group IV: Fuji Ortho and LED; Group V: Fuji Ortho, without acid and halogen light; Group VI: Fuji Ortho, without acid and LED. The groups were tested to shear strength in a universal testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed statistically by ANOVA and Tukey's test. RESULTS: The composite resin presented higher shear bond strength than the resin-modified glass ionomer cement (p<0.05). The halogen light and LED sources produced similar shear bond strength (p>0.05). CONCLUSION: The shear bond strength was influenced by the material but not by the light-curing unit. The use of LED reduced the experimental time by approximately 60 percent, with the same curing efficiency.

Power density of light curing units through resin inlays fabricated with direct and indirect composites / 대한치과보존학회지

OBJECTIVES: The purpose of this study was to measure the power density of light curing units transmitted through resin inlays fabricated with direct composite (Filtek Z350, Filtek Supreme XT) and indirect composite (Sinfony). MATERIALS AND METHODS: A3 shade of Z350, A3B and A3E shades of Supreme XT, and A3, E3, and T1 shades of Sinfony were used to fabricate the resin inlays in 1.5 mm thickness. The power density of a halogen light curing unit (Optilux 360) and an LED light curing unit (Elipar S10) through the fabricated resin inlays was measured with a hand held dental radiometer (Cure Rite). To investigate the effect of each composite layer consisting the resin inlays on light transmission, resin specimens of each shade were fabricated in 0.5 mm thickness and power density was measured through the resin specimens. RESULTS: The power density through the resin inlays was lowest with the Z350 A3, followed by Supreme XT A3B and A3E. The power density was highest with Sinfony A3, E3, and T1 (p < 0.05). The power density through 0.5 mm thick resin specimens was lowest with dentin shades, Sinfony A3, Z350 A3, Supreme XT A3B, followed by enamel shades, Supreme XT A3E and Sinfony E3. The power density was highest with translucent shade, Sinfony T1 (p < 0.05). CONCLUSIONS: Using indirect lab composites with dentin, enamel, and translucent shades rather than direct composites with one or two shades could be advantageous in transmitting curing lights through resin inlays.

Influência da fonte de luz fotoativadora nas propriedades ópticas de resína composta, em função da cor, espessura e tempo de armazenamento / Influence of the light-curing unit in optical properties of a composite resin according of shade, thickness, and storage time

Esse estudo se propõe a avaliar as propriedades ópticas (Fluorescência e Absorbância) da resina composta fotoativada (4 SEASONS®) utilizando aparelho fotopolimerizador convencional (luz Halógena Ulttralux - DabiAtlant), e aparelho emissor de Diodo (Radii ­ SDI e Ultralume Led 5- Ultradent), em função da fonte de luz foto-ativadora, cor, espessura e tempo de armazenamento em saliva artificial. Foram confeccionadas 5 amostras (10,0x1,0 mm) para cada grupo experimental. Para a realização do teste de Absorbância foi utilizado aparelho espectrofotômetro de luz visível (Diode Array Spectrophotometer, HP ­ Serial Number: 8452-A). Para a obtenção dos valores de fluorescência emitida pelas amostras, foi utilizado espectrofotômetro (SPEX TRIAX FLUOROLOG 3, Jobin Yvon ­ Serial Number: 0135B-3-99). Os resultados foram julgados estatisticamente conforme a interação entre os fatores de avaliação nos distintos trabalhos. Pode-se concluir que a fonte de luz fotoativadora influenciou apenas a emissão fluorescente da resina de cor TC, não tendo efeito negativo na absorbância; o aumento na espessura da amostra acarretou uma diminuição na emissão fluorescente e na absorbância de todas as cores da resina, independente da fonte de luz; e as diferentes cores da resina exibiram diferentes emissões fluorescentes e absorbância

The arm of this study is to evaluate optical properties (fluorescence and Absorbance) of a composite resin (4 SEASONS®) using light curing units (LCUs)-(QTH - Ulttralux ­ DabiAtlant and LEDs Radii ­ SDI and Ultralume Led 5- Ultradent) in function of LCUs, shade, thickness and storage times. 5 samples were prepared for each experimental group. To perform the Absorbance test, was used of UV-Vis spectrophotometer (Diode Array Spectrophotometer, HP ­ Serial Number: 8452-A). To obtain the fluorescence emission by samples, we used a spectrophotometer (SPEX TRIAX FLUOROLOG 3, Jobin Yvon ­ Serial Number: 0135B-3-99). The results were deemed statistically as the interaction between the evaluation factors in the different works. It can be concluded that the LCUs only influenced the fluorescent emission of resin color TC, having no negative effect on the absorbance; the increase in thickness of the sample decrease the fluorescent emission and absorbance for colors of the resin, independent of the LCUs; different colors of resin exhibited different fluorescent emission and absorbance

Light-emitting diode versus halogen light curing of orthodontic brackets: a clinical study of bond failure / Colagem de brackets ortodônticos: polimerização da resina por meio de diodos emissores de luz versus luz alógena: estudo clínico de falhas de adesão

OBJECTIVE: The purpose of this study was to evaluate the clinical performance of brackets cured with two light-curing units. MATERIALS AND METHODS: Forty female patients (between12-16 years old) who required fixed appliances were included in this study. Based on the characteristics of their lower arches, study participants were divided into two groups, A and B. In group A, the composites were cured on the right side by Ultralume LED2TM and on the left side by a conventional halogen unit. In group B, the sequence was reversed. A total of 160 brackets were bonded. After 12 months, bond failure rate was evaluated. RESULTS: We found that 18 brackets in the halogen group and 13 bracketsin the LED group were debonded. No statistically significant differences were found in total bond failure rate and no enamel damage was clinically detected for either technique. CONCLUSION: Theseresults suggest that LED dose curing does not result in more bond failure when compared with conventional halogen light curing.

OBJETIVO: O objetivo deste estudo foi avaliar o desempenho clínico de brackets colados utilizando-se de duas unidades de polimerização. MATERIAL E MÉTODO: quarenta pacientes adolescentes com indicação de tratamento ortodôntico fixo foram incluídos no trabalho, divididosem dois grupos, A e B. No grupo A, o compósito foi polimerizado no lado direito com Ultralume LED 2TM e no lado esquerdo com luz halógena convencional. No grupo B, a sequencia foi invertida. Um total de 160 brackets foram colados. Após 12 meses de tratamento, avaliou-se a taxa de falhas de colagem. RESULTADOS: 18 brackets no grupo halógeno e 13 no grupo LED sofreram descolamento. Não houve diferença estatisticamente significante na taxa total de falhas e nãoforam observados danos ao esmalte em ambas as técnicas. CONCLUSÃO: Estes resultados sugerem que a fotopolimerização com LED não resulta em maiores falhas de adesão quandocomparadas com a luz halógena convencional.

Polymerization shrinkage stress of composites photoactivated by different light sources

The purpose of this study was to compare the polymerization shrinkage stress of composite resins (microfilled, microhybrid and hybrid) photoactivated by quartz-tungsten halogen light (QTH) and light-emitting diode (LED). Glass rods (5.0 mm x 5.0 cm) were fabricated and had one of the surfaces air-abraded with aluminum oxide and coated with a layer of an adhesive system, which was photoactivated with the QTH unit. The glass rods were vertically assembled, in pairs, to a universal testing machine and the composites were applied to the lower rod. The upper rod was placed closer, at 2 mm, and an extensometer was attached to the rods. The 20 composites were polymerized by either QTH (n=10) or LED (n=10) curing units. Polymerization was carried out using 2 devices positioned in opposite sides, which were simultaneously activated for 40 s. Shrinkage stress was analyzed twice: shortly after polymerization (t40s) and 10 min later (t10min). Data were analyzed statistically by 2-way ANOVA and Tukey's test (a=5 percent). The shrinkage stress for all composites was higher at t10min than at t40s, regardless of the activation source. Microfilled composite resins showed lower shrinkage stress values compared to the other composite resins. For the hybrid and microhybrid composite resins, the light source had no influence on the shrinkage stress, except for microfilled composite at t10min. It may be concluded that the composition of composite resins is the factor with the strongest influence on shrinkage stress.

Este estudo comparou a contração de polimerização de resinas compostas fotoativadas por luz halógena (QTH) e diodo emissor de luz (LED). Foram confeccionados bastões de vidro (5,0 mm x 5,0 cm), e uma de suas extremidades sofreu jateamento com óxido de alumínio, sobre a qual foi aplicado um adesivo e fotoativado com luz halógena. Os bastões de vidro foram acoplados verticalmente, em pares, em uma máquina universal de ensaios (EMIC DL-2000) e as resinas compostas aplicadas no bastão inferior. A distância entre os bastões foi padronizada em 2 mm e um extensômetro foi acoplado a eles. As resinas foram fotoativadas (n=20), sendo 10 por QTH e 10 por LED utilizando dois aparelhos posicionados em lados opostos, acionados simultaneamente por 40 s. A tensão de contração foi analisada em dois momentos: logo após a polimerização (t40s) e 10 min após (t10min). A tensão de contração apresentada por todas as resinas foi maior em t10min do que em t40s, independente da fonte ativadora. A resina de micropartículas apresentou menores valores de tensão de contração com valores estatisticamente significantes em relação às demais resinas. Para as resinas híbrida e microhíbrida não houve influência da unidade ativadora sobre a tensão de contração, com exceção para a resina de micropartículas em t10min. Concluiu-se que a composição da resina composta foi o fator que mais interferiu na tensão de contração da resina composta.

Variação térmica da câmara pulpar e do gel clareador bloqueador de infravermelho ativado com lâmpada halógena / Temperature changes of pulpal chamber and infrared-blocking bleaching gel activated with halogen light

Objetivo: Avaliar a temperatura da câmara pulpar (CP) e do gel clareador bloqueador de infravermelho na superfície dental (SUP), durante a ativação com fotopolimerizadores com lâmpadas halógenas que emitem radiação na faixa do infravermelho (IV). Metodologia: Os géis clareadores Whiteness HP Maxx (com bloqueador de IV - MX) e Whiteness HP (controle - CON) foram aplicados em 10 incisivos centrais superiores. A ativação com luz foi realizada com os fotopolimerizadores (FP) Optilight (600mW/cm2, OP) e Jet Lite (1200mW/cm2, JL), sendo quatro ativações de 40s, sem intervalo (total de 3min e 20s). As temperaturas foram aferidas a cada 40s com um termômetro digital com dois termopares tipo K, um no interior da CP e outro na superfície dental (SUP). Os dados foram analisados com ANOVA a 3 fatores (tipo de gel - TG, FP e tempo de ativação) e teste de Tukey. Resultados: Houve efeito significativo de TG e FP e para a interação FP/TG. As médias (DP) (em graus Celsius) foram: PC:[GT={MX-6,38(3,25)a, CON-7,70(2,91)b}, FC={OP-5,51(2,54)a, JL-8,56(2,93)b}]; SUR: [GT={CON-9,85(3,89)a, MX-14,21(7,76)b}, FC={OP-7,32(2,50)a, JL-16,74(5,82)b}]. Conclusões: O gel bloqueador de IV resultou em menor aquecimento da CP e maior aquecimento do gel que o controle. O FP Jet Lite promoveu maior aquecimento que o Optilight.

Purpose: To evaluate temperature changes of pulpal chamber (PC) and infrared blocking bleaching gel on dental surface (SUR) during the activation with photocuring units with halogen lights that emit radiation in the infrared (IR) range. Methods: The bleaching gels Whiteness HP Maxx (IR-blocker - MX) and Whiteness HP (control - CON) were used in ten maxillary central incisors. Light-activation was performed by using the photocuring units (FC) Optilight (600mW/cm2, OP) or Jet Lite (1200mW/cm2, JL) with four 40s-activation procedures with no interval (total time: 3min 20s). The temperature was measured each 40s using a digital thermometer with two type K thermocouples placed inside the PC and on dental surface (SUR). Data were analyzed with 3-way ANOVA (gel type - GT, FC and activation time) and Tukey's test. Results: A significant effect was found for the main factors FC and GT, and for their interaction. The means (SD) (in Celsius degree) were: PC:[GT={MX-6,38(3,25)a, CON-7,70(2,91)b}, FC={OP-5,51(2,54)a, JL-8,56(2,93)b}]; SUR: [GT={CON-9,85(3,89)a, MX-14,21(7,76)b}, FC={OP-7,32(2,50)a, JL-16,74(5,82)b}]. Conclusions: MX resulted in lower pulp chamber heating and higher gel heating than the control group. JL promoted greater heating than OP.

Effect of light-curing units and activation mode on polymerization shrinkage and shrinkage stress of composite resins

The aim of this study was to evaluate the polymerization shrinkage and shrinkage stress of composites polymerized with a LED and a quartz tungsten halogen (QTH) light sources. The LED was used in a conventional mode (CM) and the QTH was used in both conventional and pulse-delay modes (PD). The composite resins used were Z100, A110, SureFil and Bisfil 2B (chemical-cured). Composite deformation upon polymerization was measured by the strain gauge method. The shrinkage stress was measured by photoelastic analysis. The polymerization shrinkage data were analyzed statistically using two-way ANOVA and Tukey test (p<0.05), and the stress data were analyzed by one-way ANOVA and Tukey's test (p<0.05). Shrinkage and stress means of Bisfil 2B were statistically significant lower than those of Z100, A110 and SureFil. In general, the PD mode reduced the contraction and the stress values when compared to CM. LED generated the same stress as QTH in conventional mode. Regardless of the activation mode, SureFil produced lower contraction and stress values than the other light-cured resins. Conversely, Z100 and A110 produced the greatest contraction and stress values. As expected, the chemically cured resin generated lower shrinkage and stress than the light-cured resins. In conclusion, The PD mode effectively decreased contraction stress for Z100 and A110. Development of stress in light-cured resins depended on the shrinkage value.

Color stability of composites subjected to accelerated aging after curing using either a halogen or a light emitting diode source

The purpose of this study was to evaluate, in vitro, the color stability of three composite resins of two different shades (A3 and C3) cured with either a quartz tungsten halogen (QTH) or a light emitting diode (LED) source. Forty specimens (20 x 2 mm) were prepared for each composite (Tetric Ceram®, Heliomolar® and Esthet-X®), being 20 for each shade. In each group, 10 specimens were light-cured using the QTH unit and 10 with the LED source. The shade of the materials was evaluated before and after submitting the specimens to artificial accelerated aging (4 h UV-B/4 h condensing vapor), using a reflection spectrophotometer. deltaE means were calculated and analyzed statistically by 2-way ANOVA and Tukey's test at 5 percent significance level. Both A3 and C3 shades of Esthet-X composite resin showed the lowest color change when cured with the QTH light, while Tetric C3 cured with the QTH light showed the highest color change.

O objetivo deste estudo foi verificar a estabilidade de cor de três compósitos polimerizados com dois tipos de unidades polimerizadoras, luz halógena ou diodo emissor de luz (LED). Quarenta amostras (20 mm de diâmetro por 2 mm de espessura) foram construídas com cada compósito (Tetric Ceram®, Heliomolar® and Esthet-X®), vinte na cor A3 e vinte na cor C3. Dentro de cada grupo, 10 amostras foram polimerizadas com luz halógena e as outras com LED. A cor dos materiais foi verificada antes e depois das amostras serem submetidas ao envelhecimento artificial acelerado (4h UV-B/4h de condensação de vapor), usando um espectrofotômetro de reflexão. As médias deltaE de foram calculadas e analisadas estatisticamente (ANOVA a dois critérios e teste de Tukey, 95 por cento). Os compósitos Esthet-X A3 e C3 demonstraram a menor alteração de cor quando polimerizados com luz halógena enquanto a resina. Tetric C3 apresentou a maior alteração de cor quando polimerizada por essa mesma fonte de luz.

Efeito da polimerização por LED na microinfiltração marginal das restaurações classe II de resina composta / Effect of LED curing on microleakage of class II composite resin restorations

A proposta do trabalho foi avaliar o grau de microinfiltração marginal do sistema adesivo Single Bond (3M ESPE) por meio de dois diferentes tipos de fotopolimerizadores. Foram utilizados dez pré-molares humanos e confeccionadas cavidades do tipo classe II, sendo uma ocluso-mesial e outra ocluso-distal, com término oclusal em esmalte e término cervical localizado em cemento, em seguida, restauradas com Single Bond (3M ESPE) e resina composta Filtek Z250 (3M ESPE) cor A2. Os dentes foram divididos em dois grupos: Grupo 1 û fotopolimerizado com o aparelho de luz halógena Optilight (Gnatus); Grupo 2 û fotopolimerizado com o aparelho sem fio LED Radii (SDI). Os dentes e os forames apicais foram isolados, deixando exposta à margem de 1,0 mm ao redor da restauração, sendo em seguida termociclados 250 vezes (±5°C e ±55°C). Após, os corpos-de-prova foram mergulhados em solução de fucsina básica a 0,5 porcento por 48 horas para posterior avaliação obedecendo aos escores: grau 0 û ausência de infiltração; grau 1 û infiltração até 1/3 da parede; grau 2 û infiltração entre 1/3 a 2/3 da parede e grau 3 û infiltração mais do que 2/3 da parede. Os escores para dentina foram: G1: 0 = 100 porcento; G2: 0 = 70 porcento; 1 = 10 porcento; 2 = 20 porcento. Para esmalte: G1: 0 = 90 porcento; 1 = 10 porcento; G2: 0 = 50 porcento; 2 = 20 porcento; G3 = 30 porcento. Os resultados foram submetidos à análise estatística de Mann-Whitney (p < 0,05), demonstrando não haver diferença estatisticamente significante entre os grupos. Concluiu-se que a microinfiltração marginal não foi influenciada negativamente quando foi empregada a unidade fotopolimerizadora LED

The purpose of this study was to evaluate the microleakage of the bonding system Single Bond (3M ESPE) when used 2 differents light-curing units. Class II cavities were prepared in 10 human premolars. After, the cavities prepared were treated with the bonding agent Single Bond (3M ESPE) and filled with Filtek Z250 (3M ESPE) composite resin, color A2. The teeth were divided into 2 groups: G1 ­ the restorations were light-cured with a conventional halogen-based light-curing unit (Gnatus); G2 ­ the restorations were cured with a LED cordless light-curing unit Radii (SDI). The specimes were thermo-cycled 250 cycles (± 5 °C and ± 55 °C) prior to immersion in 0.5% basic fuchsin for 48 hours for posterior evaluation. The scores in dentin were: G1: 0 = 100%; G2: 0 = 70%; 1 = 10%; 2 = 20%. In the enamel: G1: 0 = 90%; 1 = 10%; G2: 0 = 50%;­ 2 = 20%; G3 = 30%. The data were subjected to statistical analysis using Mann-Whitney test (p < 0.05) and showed no significant statistical difference between the groups. In conclusion the LED light source no influenced the microleakage