Clinical Guidelines for Photocuring

Caughman, W. Frank; Rueggeberg, Frederick A.; Curtis, James

doi:10.14219/jada.archive.1995.0364

Cited by 112 publications

(101 citation statements)

References 4 publications

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“…This was observed for both surfaces, although it was more evident in the L surfaces than in the U surfaces. Despite the statistically different mean values, a short irradiation time of 10 s was able to produce a high hardness value on the U surface, which is in agreement with other studies (12,17).…”

Section: Discussionsupporting

confidence: 92%

“…In this state, camphoroquinone overreacts with an amine-reducing agent in order to form free radicals (12). Thus, it must be emphasized that, in addition to the type of restorative material, the light-curing unit plays a very important role on the polymerization process.…”

Section: Discussionmentioning

confidence: 99%

“…The degree of polymerization of these materials is basically proportional to the material thickness and irradiation time (1), which depend on some variables, such as type of material, composite shade, distance and quality of light source. For an adequate polymerization of a 2-mmthick composite increment is recommended an energy density between 21 and 24 J/cm 2 (11), therefore, to light cure a 2-mm-thick composite increment is required a minimum irradiance of 400 mW/cm 2 for 40-60 s (12)(13)(14) and 280 mW/cm 2 for 60 s to light cure a 1-mm-thick composite increment (12).The surface near the light source can be considered well polymerized for 20 s at an irradiance as low as 200 mW/cm 2 because there is no interference with light transmission (1,14). The amount of light exposure time indicated by the composite manufacturer must be extended whenever the irradiance is reduced due to distance or any other factor.…”

Section: Introductionmentioning

confidence: 99%

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Influence of shade and irradiation time on the hardness of composite resins

2007

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This study tested the following hypotheses: 1. increasing light irradiation time (IT) produces greater values of superficial hardness on different depths (0 and 3 mm); and 2. a dark shade composite (A3) needs longer IT than a light shade composite (A1) to produce similar hardness. Disk-shaped specimens (n=24 per shade) were fabricated using a 3-mm-thick increment of composite resin (Z100). Specimens were randomly assigned to 3 groups (n=8) according to the IT (400 mW/cm2) at the upper (U) surface: A1-10 and A3-10: 10 s; A1-20 and A3-20: 20 s; A1-40 and A3-40: 40 s. Specimens were stored in black lightproof containers at 37 o C for 24 h before indentation in a hardness tester. Three Vickers indentations were performed on the U and lower (L) surfaces of each specimen. The indent diagonals were measured and the hardness value calculated. The results were analyzed statistically by ANOVA and Tukey's test (α=0.05). Statistically significant differences were found between U and L surfaces of each composite shade-IT combination (p=0.0001) and among the ITs of same shade-surface combination (p=0.0001), except between groups A1-20U and A1-40U, confirming the study hypothesis 1 and partially rejecting the hypothesis 2.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Influence of shade and irradiation time on the hardness of composite resins

2007

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“…We aimed to accomplish similar depths of cure of dental composites, to those obtained with a halogen LCU having a minimum level of irradiance of 300 mWcm -2 . 7,8 …”

Section: Methodsmentioning

confidence: 99%

“…The lower effective limit of irradiance for halogen technology based LCUs used in dental practice has been suggested to be 300 mWcm -2 . 7,8 Some halogen LCUs available presently exceed an irradiance of 1000 mWcm -2 .…”

Section: Researchmentioning

confidence: 99%

Dental composite depth of cure with halogen and blue light emitting diode technology

1999

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Objectives To test the hypothesis that a blue light emitting diode (LED) light curing unit (LCU) can produce an equal dental composite depth of cure to a halogen LCU adjusted to give an irradiance of 300 mWcm–2 and to characterise the LCU's light outputs. Materials and methods Depth of cure for three popular composites was determined using a penetrometer. The Student's t test was used to analyse the depth of cure results. A power meter and a spectrometer measured the light output. Results The spectral distribution of the LCUs differed strongly. The irradiance for the LED and halogen LCUs were 290 mWcm–2 and 455 mWcm–2, when calculated from the scientific power meter measurements. The LED LCU cured all three dental composites to a significantly greater (P < 0.05) depth than the halogen LCU. Conclusions An LED LCU with an irradiance 64% of a halogen LCU achieved a significantly greater depth of cure. The LCU's spectral distribution of emitted light should be considered in addition to irradiance as a performance indicator. LED LCUs may have a potential for use in dental practice because their performance does not significantly reduce with time as do conventional halogen LCUs

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