The Effects of Temperature and Light Intensity on the Polymerization Shrinkage of Light-cured Composite Filling Materials

2006 ◽  
Vol 7 (3) ◽  
pp. 12-21 ◽  
Author(s):  
Ahmed A. Elhejazi
Keyword(s):  
Light Intensity ◽  
Room Temperature ◽  
Environmental Temperature ◽  
Composite Resin ◽  
Comparable Amount ◽  
Polymerization Shrinkage ◽  
Filling Materials ◽  
Lower Light ◽  
Effects Of Temperature ◽  
Effect Of Light

Abstract The aim of this study was to investigate the effect of light intensity on polymerization shrinkage of resin composites. The five materials tested were Lite-Fil (A) (LFA), Lite-Fil (P) (LFP), Z100, Palfique, (PAL) and Tetric (TRC). Two types of measurements were made to determine the effects of environmental temperature and light intensity. Results were analyzed by two-way analysis of variance (ANOVA) and Newman-Keuls procedure at (P<0.05). The changes in temperature and/or light intensity strongly affected composite shrinkage. The amount of shrinkage for LFP at 100% light intensity in room temperature (23°C) was 1.26% and increased up to 2.29% at 60°C. By raising the temperature to 37°C and dropping the light intensity to 42% (459mW/cm2), the amount of polymerization shrinkage was similar to that with full light intensity, and statistically there were no significant differences between 37°C, 45°C, and 60°C. Lower temperatures and lower light intensities produce lower values of shrinkage. However, if the light intensity is below 28%, higher temperatures (60°C) must be applied to obtain a comparable amount of shrinkage. Clinical Relevance Pre-heating composite resin materials at body temperature (37°C) is likely to improve physical properties and compensate any drop of light intensity. Citation Elhejazi AA. The Effects of Temperature and Light Intensity on the Polymerization Shrinkage of Light-cured Composite Filling Materials. J Contemp Dent Pract 2006 July;(7)3:012-021.

scholarly journals Effect of light intensity and irradiation time on the polymerization process of a dental composite resin

2004 ◽  
Vol 7 (2) ◽  
pp. 313-318 ◽  
Author(s):  
José Augusto César Discacciati ◽  
Alisson Discacciati Neves ◽  
Rodrigo Lambert Oréfice ◽  
Flávio Juliano Garcia Santos Pimenta ◽  
Herbert Haueisen Sander
Keyword(s):  
Light Intensity ◽  
Composite Resin ◽  
Irradiation Time ◽  
Dental Composite ◽  
Polymerization Process ◽  
Dental Composite Resin ◽  
Effect Of Light

scholarly journals Evaluation of Pre-heating Effects on Marginal Adaptation of Resin-based Materials

2018 ◽  
Vol 55 (2) ◽  
pp. 238-242 ◽  
Author(s):  
Ionut Taraboanta ◽  
Simona Stoleriu ◽  
Gianina Iovan ◽  
Antonia Moldovanu ◽  
Andrei Georgescu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Composite Resin ◽  
Optical Microscope ◽  
Marginal Adaptation ◽  
Gap Formation ◽  
Solution Ph ◽  
Filling Materials ◽  
Heating Effects ◽  
Direct Restoration ◽  
Materials Used

The aim of the study was to compare the marginal adaptation of three different resin-based materials used for direct restoration: hybrid composite resin (Gaenial Posterio, GC Corporation), a compomer (Dyract eXtra, Dentsply Sirona), and a giomer (Beautifil II, Shofu Dental) applied at room temperature or after preheated at preheating 50 and 60oC. Class II cavities were prepared on proximal surfaces of extracted teeth and randomly divided in 3 groups according to the material used for restoration. In each group five cavities were restored using the materials at room temperature (subgroup 1), five cavities were restored using preheated materials at 50şC (subgroup 2), and five cavities were restored using preheated materials at 60şC (subgroup 3). The teeth were stored in distilled water for 14 days and then were immersed in 2% methylene blue buffered dye solution (pH = 7) for 4 hours. The teeth were transversally cut and the sections were examined using optical microscope (Carl-Zeiss AXIO Imager A1m) at 50x magnification and the dye penetration was evaluated according to 4 scores. Decreased microleakage and fewer gap formation were recorded for all filling materials after they have been heated at 50 or 60oC. Pre-warming of resin-based materials improves the adaptation of these materials to tooth structures.

scholarly journals Effect of light intensity and growth substratum on plant development and production of secondary metabolites in Cordia curassavica (Jacq.) Roem. & Schult

2010 ◽  
Vol 34 (3) ◽  
pp. 417-423 ◽  
Author(s):  
Maria Terezinha Silveira Paulilo ◽  
Flávia Simão Lapa ◽  
Miriam de Barcellos Falkenberg
Keyword(s):  
Light Intensity ◽  
Root Biomass ◽  
Relative Income ◽  
High Light Intensity ◽  
High Light ◽  
Alcoholic Extract ◽  
Low Light ◽  
Fertilized Soil ◽  
Lower Light ◽  
Effect Of Light

Cordia curassavica (Jacq.) Roem. & Schult. (Boraginaceae), also referred to as Cordia verbenacea DC, has been traditionally used for medicinal purposes. This study was driven to verify the behavior of the species in similar conditions to its natural environment, such as high light intensity and sandbank soil, and in conditions of low light intensity and fertilized substratum (dystroferric red nitosoil plus earthworm humus). The growth of the plant, the income of leaf crude extracts and, in the alcoholic extract, the number of substances found in thin layer cromatography and the toxicity of the substratum was observed. The results indicated that the growth of the root biomass, stem and leaves in discharge or lower light intensity was similar, but smaller in sandbank soil than in fertilized soil. The relative income of extracts in ether of petroleum and alcohol was larger in high light intensity and fertilized substratum. The light intensity and the substratum type didn't affect the number of substances detected in the alcoholic extract or the toxicity of this extract. Stains corresponding to the rosmarinic acid were only evidenced in some samples of the alcoholic extract, not allowing the verification of the effect of the treatments about its production.

Evaluation of the formation of marginal gaps in preheated composite resin restorations

2014 ◽  
Author(s):  
Marco Antonio Gallito
Keyword(s):  
Room Temperature ◽  
Composite Resin ◽  
Resin Composite ◽  
Polymeric Materials ◽  
Sem Analysis ◽  
Composite Resins ◽  
Posterior Teeth ◽  
Polymerization Shrinkage ◽  
Composite Resin Restorations ◽  
Resin Restorations

Composite resins are polymeric restorative materials that have acceptable mechanical properties, so they are used in anterior and posterior teeth. There is, however, polymerization shrinkage inherent in the polymeric materials. This contraction is responsible for the formation of cracks at the interface of the restoration. These gaps contribute to the staining of the composite resin and the appearance of cavities. In order to minimize the effects of polymerization shrinkage, variations in restorative technique has been introduced to fulfill this goal. The preheating resin composite is one of them.This study aimed to assess the formation of marginal gaps, using scan electron microscopy, in composite resin restorations created using one room-temperature composite resin and one preheated to 60°C. 20 recently-extracted human molars with circular cavities in the surface dentine of each proximal surface were used. The cavities were restored using Filtek Z350 (3M) composite resin affixed with Adper Scotchbond Multipurpose Adhesive (3M) and divided into two groups of 10 samples: group 1 – room-temperature composite resin restorations (n=10) and group 2 – composite resin restorations preheated to 60oC (n=10). The samples were kept in a bacteriological incubator for a period of seven days. After this, the restorations were polished and epoxy resin replicas were created using a casting with addition silicone for subsequent SEM analysis. The gaps were measured with the aid of UTHSCSA Image tool software and the results were submitted to Student “t” test statistical analysis, achieving the following results: the highest marginal gap figures were obtained with Filtek Z350 resin preheated to 60oC (t= -3.961 and p=0.000). Based on the methodology employed and the results achieved, it can be concluded that there was a greater formation of marginal gaps in the dentin-composite resin interface where Filtek Z350 resin preheated to 60°C was used for restorations, thus making it preferable to use room-temperature composite resin.Keywords:Composite resin. Marginal gaps. Electronic microscopy.

scholarly journals The effect of light intensities on morpho-physiological and biochemical of black pepper (Piper nigrum L.)

2021 ◽  
Vol 306 ◽  
pp. 01009
Author(s):  
Issukindarsyah ◽  
Endang Sulistyaningsih ◽  
Didik Indradewa ◽  
Eka T. Susila Putra
Keyword(s):  
Light Intensity ◽  
Reductase Activity ◽  
Sucrose Concentration ◽  
Morphological Characters ◽  
Black Pepper ◽  
Piper Nigrum ◽  
Light Intensities ◽  
Lower Light ◽  
The Difference ◽  
Effect Of Light

The difference in the levels of light intensity was responded with changes in morphophysiological and biochemical characters of plants, especially in leaves of black pepper. The aim of this study was to determine the effect of several levels of light intensity on the morphophysiological and biochemical characters of leaves of black pepper. The research was conducted in July - November 2017 in Kemuja, Mendobarat, Bangka Belitung. This study used split-plot design with three replications. The main plots were the levels of light intensity, namely 100%, 75%, and 50%. Subplots were varieties of black pepper, namely Petaling 1, Petaling 2, and Nyelungkup. The results showed that there was no interaction between varieties and light intensities. The morphophysiological and biochemical responses of the leaves of the three varieties tested were the same at all levels of light intensity. Light intensity up to 50% has no effect on leaf morphological characters, but leaves become thinner at lower light intensities. Chlorophyll, nitrate reductase activity and leaf sucrose concentration were same at all light intensities up to 50%. Plants exposed to higher light intensity have a higher number of stomata. The results concluded that the light intensity of up to 50% did not cause changes in leaf morphology and biochemistry and only affected leaf stomata density.

Effect of light intensity on a composite resin shrinkage

2012 ◽  
Vol 28 ◽  
pp. e44
Author(s):  
A.K.F. Costa ◽  
R.N. Tango ◽  
T.J.A. Paes ◽  
A.C.O. Souza ◽  
A.L.S. Borges
Keyword(s):  
Light Intensity ◽  
Composite Resin ◽  
Effect Of Light

The Influence of Environmental Factors on Infection of Rush Skeletonweed (Chondrilla juncea) by Puccinia chondrillina

Weed Science ◽  
1981 ◽  
Vol 29 (3) ◽  
pp. 364-367 ◽  
Author(s):  
Bonnie L. Blanchette ◽  
G. A. Lee
Keyword(s):  
Biological Control ◽  
Environmental Factors ◽  
Light Intensity ◽  
Environmental Conditions ◽  
Germ Tube ◽  
Light Intensities ◽  
Effects Of Temperature ◽  
Rush Skeletonweed ◽  
Effect Of Light ◽  
Chondrilla Juncea

The effects of temperature and dew period on infectivity of Puccinia chondrillina Bubak and Syd. and the effect of light intensity on uredospore germination were studied under controlled environmental conditions. When rush skeletonweed (Chondrilla juncea L.) plants were inoculated with uredospores at 8, 16, and 24 C, larger pustules developed faster at 24 C than at the cooler temperatures. The greatest amount of infection occurred at 8 and 16 C (75% of the leaf area infected compared to 25% at 24 C). The greater number of infection sites at cooler temperatures was coincident with an increase in uredospore germination at 8 and 16 C compared to 24 C. Increasing the dew period from 0 to 6 h increased the amount of infection by the rust. Light intensities as low as 0.5 klux significantly reduced uredospore germination on water agar. Germ tube growth was restricted significantly by light intensities of 2.5 to 4.5 klux. Applications of uredospores to aid in biological control of this serious weed would be most successful if made at dusk under cool temperatures when an extended dew period is expected.

scholarly journals Effect of Light Intensity and Curing Time on Color Stability of a Methacrylate-Based Composite Resin Using an LED Light-Curing Unit

2019 ◽  
Vol 11 (3) ◽  
pp. 83-88
Author(s):  
Hosna Teimourian ◽  
Negin Farahmandpour ◽  
Maryam Zali Moghadam ◽  
Hoda Pouyanfar ◽  
Narges Panahandeh
Keyword(s):  
Light Intensity ◽  
Composite Resin ◽  
Color Stability ◽  
Curing Time ◽  
Led Light ◽  
Light Curing ◽  
Effect Of Light

scholarly journals Effect of light intensity on reproduction of Polish, Swedish, and Danish chinchillas

2005 ◽  
Vol 48 (5) ◽  
pp. 494-504 ◽  
Author(s):  
L. Felska-Błaszczyk ◽  
M. Brzozowski
Keyword(s):  
Light Intensity ◽  
Litter Size ◽  
Death Rate ◽  
Intensity Level ◽  
Genetic Groups ◽  
Reproduction Performance ◽  
Artificial Illumination ◽  
Lower Light ◽  
Offspring Mortality ◽  
Effect Of Light

Abstract. The aim of this study was to determine at what level of artificial illumination the best reproduction performance can be achieved, as well as how varied light intensity affects chinchillas of different genetic groups. Reproduction performance was evaluated for 100 Polish, 52 Swedish, and 83 Danish females. Light intensity, measured with a photoelectric light meter LS-200, ranged between 0 and 100 lx. The chinchillas were assigned to 5 groups, 20-lx interval each. The analysis included: mean litter size, mean number of weaned per litter, death rate during nursing, number of litters per female per year, as well as litter size and number of weaned per female per year. For each genetic group, the highest death rate of the young was found at the lowest light intensity level, i.e. 0-20 lx, while the lowest mortality was at 41-60 lx. Both Swedish and Danish chinchillas had lower nursing mortality at a higher level of illumination (61-100 lx), while higher mortality was recorded at lower light intensity (0-40 lx), compared to Polish chinchillas. It can be concluded that light intensity affects chinchilla reproduction, since higher litter sizes and reduced offspring mortality were observed under stronger light. Danish females attained the highest number of litters per year, the largest litter size and the highest number of weaned per year at the light intensity of 61-80 lx, compared to the other genetic groups. Chinchillas proved to be sensitive to very small changes in light intensity.

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