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Query: UMLS:C0033036 (APC)
 10,214 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

With the introduction of photosensitive (light-cured) restorative materials in dentistry, various methods were suggested to enhance their polymerization and to shorten the curing time including layering and the use of more powerful light-curing devices. The purpose of this study was to determine the effect of using a new light-curing apparatus that uses a light-emitting diode (LED) on the shear bond strength of an orthodontic adhesive. The new light-curing apparatus used in the study was UltraLume 2 (Ultradent USA, South Jordan, Utah) that has an 8-mm footprint and can simultaneously cure two orthodontic brackets. Forty teeth were etched with 37% phosphoric acid, washed and dried, and sealant applied, and then precoated brackets with the Transbond adhesive (APC II, 3M Unitek, Monrovia, Calif) were placed. The teeth were randomly divided into two groups according to the curing light used. In group I (control), 20 brackets were cured using an Ortholux (3M Unitek) halogen curing light for 20 seconds. In group II, 20 brackets were cured using the new LED light for 20 seconds. The findings indicated no significant (P = .343) differences in the shear bond strength between the Ortholux halogen light (5.1 +/- 2.5 MPa) and the UltraLume 2 LED light when the two groups were compared using Student's t-test (t = -0.961). In conclusion, the advantages of the new unit include the ability to cure two brackets at a time and a smaller light-emitting apparatus for the clinician to handle.
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PMID:Evaluation of a new curing light on the shear bond strength of orthodontic brackets. 1294 May 64

Little is known about the performance of Transbond Plus Self-Etching Primer (TPSEP), especially when used with Adhesive Precoated Brackets (APC 1 and APC 2). The aim of this study was to compare the shear bond and rebond strengths and failure sites of APC 1 and APC 2 with a non-coated bracket system [Victory Series (V)] using Transbond XT light-cured adhesive and TPSEP or 37 percent phosphoric acid as the conditioner. The results demonstrated that on dry testing of 120 brackets when applying an occluso-gingival load to produce a shear force at the bracket-tooth interface, there was no statistically significant difference in the shear bond strength (SBS) of APC 1 (68.4 N), APC 2 (74.9 N), and V brackets (75.4 N, control group). There was also no significant difference in bond failure sites of the APC 1 and APC 2 when compared with the non-coated bracket system using Transbond XT light-cured adhesive and TPSEP, with bond failure for all groups occurring mainly at the adhesive-enamel interface. There was a significant difference in the SBS of the V brackets when using TPSEP and 37 percent phosphoric acid as the conditioners. The latter was lower (60.6 N) and the bond failure site changed from the enamel-adhesive interface to the bracket-adhesive interface. The shear rebond strengths of all bracket types were statistically significantly lower (P < 0.05) than their initial SBS (APC 1, APC 2, and V: 35.9, 36.7, and 34.1 N, respectively) and the locus of bond failure altered from the adhesive-enamel interface to the bracket-adhesive interface. A clinical trial using TPSEP as a conditioner would be useful as the time taken to remove the adhesive from the enamel surface may be reduced following debond.
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PMID:Bonding characteristics of a self-etching primer and precoated brackets: an in vitro study. 1649 72

This study determined the influence of light curing protocols and matrix type on the margin quality and marginal seal of Class II resin-based composite restorations. In extracted human molars, box-shaped MOD cavities with 1 mm wide interproximal bevels were prepared with cervical margins located at least 1 mm coronal to the cemento-enamel junction. The prepared teeth were mounted in a jig featuring artificial training teeth that served as adjacent teeth. A contoured sectional metal matrix band was placed in one interproximal area, and a section of a contoured transparent matrix band was placed in the opposite interproximal area. Both were kept in position using wooden wedges. After etching (35% H3PO4 gel) and the application of a three-step etch & rinse dentin adhesive (Optibond FL, Kerr), a thin layer of flowable resin-based composite (Revolution, Kerr) was applied to the interproximal margins. The cavities were restored by placing one horizontal and two oblique increments of a fine hybrid resin-based composite (Herculite XRV, Kerr). The curing protocols included one standard halogen protocol (Elipar Trilight, 3M ESPE, 40 seconds @ 800 mW/cm2), 3 halogen soft-start protocols (Step: Elipar HiLight, 3M ESPE; 10 seconds @ 150 mW/cm2, 30 seconds @ 850 mW/cm2; Ramp: Elipar TriLight, 3M ESPE, 5 seconds @ 100 mW/cm2, exponential increase for 10 seconds, 25 seconds @ 800 mW/cm2; Pulse delay: VIP Light, BISCO, cervical increment: 10 seconds @ 500 mW/cm2, occlusal increments: 3 seconds @ 200 mW/cm2, final irradiation after a 5 minute interval: 30 seconds @ mW/cm2) and 2 plasma arc high intensity protocols (PAC: Lightning Cure, ADT, 10 seconds @ 1400 mW/cm2; APO: Apollo 95E, DMDS, 2 x 3 seconds @ 1570 mW/cm2). The restored teeth were stored in 0.9% saline at 37 degrees C for 4 weeks and submitted to thermal cycling [TC] with 2500 cycles between 5 degrees C and 55 degrees C after 2 weeks. The margin quality before and after TC was analyzed in SEM using the replica technique, and the marginal seal was determined using the dye penetration test (50% AgNO3, 2 hours) at the end of the study. The matrix type did not significantly influence the quality and seal of the respective margins. For the complete restoration margin, one of the high intensity protocols (APO) produced a higher percentage of "continuous margin" compared to pulse delay irradiation after TC and lower percentages of "marginal opening" compared to halogen standard irradiation before and after TC. Halogen step irradiation produced a superior marginal seal compared to pulse delay curing at the occlusal margins; equivalent results were observed for all curing modes at the cervical margins. Neither a general advantage of soft-start irradiation nor a general disadvantage of high intensity curing was confirmed.
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PMID:Influence of curing methods and matrix type on the marginal seal of class II resin-based composite restorations in vitro. 1653

The purpose of this study was to compare the shear bond strength of orthodontic metallic brackets photo-activated with two different light-curing sources at different exposure times: halogen light (XL 1500, 3M ESPE) and LED light (Ortholux, 3M Unitek). Sixty bovine permanent lower incisors were inserted into PVC tubes containing plaster. The buccal surfaces were cleaned with pumice and water, and then etched with 37% phosphoric acid gel. The XT Primer bonding agent (3M Unitek) was applied to the enamel surfaces and the metallic pre-coated brackets (Transbond APC II system, 3M Unitek) were attached to upper central incisors. The teeth were randomly divided into four groups (n=15). In Group I (Control), halogen light was used for 40 seconds, while in Groups II, III, and IV were light-cured with LED light unit for 40, 10, and 5 seconds, respectively. The teeth were stored in distilled water at 37 degrees C for 24 hours. The brackets were submitted to shear bond strength test in universal testing machine (Instron) at a crosshead speed of 0.5 mm/minute. Shear bond strength means (MPa) were 4.87 for Group I; 5.89 for Group II; 4.83 for Group III, and 4.39 for Group IV. Tukey's test detected no statistically significant differences among the groups regarding the shear bond strength (p>0.05). Neither of the types of light-curing sources or exposure times influenced the shear bond strength of metallic brackets.
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PMID:Shear bond strength of metallic brackets photo-activated with light-emitting diode (LED) at different exposure times. 1908 70