Halogen versus high-intensity light-curing of uncoated and pre-coated brackets: a shear bond strength study

<p>This study investigated the effect of a modified photoactivation protocol using two simultaneous light-curing units on the shear bond strength (SBS) of brackets to enamel. Metal brackets were bonded to bovine incisors using the resin-based orthodontic cement Transbond XT (3M Unitek). Four photoactivation protocols of the orthodontic cement were tested (n=15): Control: photoactivation for 10 s on each proximal face of the bracket at a time; Simultaneous: photoactivation for 10 s on both proximal faces of the bracket at the same time; One side-20s: photoactivation for 20 s at one proximal face of the bracket only; and One side-10s: photoactivation for 10 s only at one proximal face of the bracket. SBS was tested immediately or after 1000 thermal cycles. Adhesive remnant index (ARI) was classified. Data were subjected to two-way ANOVA and Student-Newman-Keuls' test (α=0.05). Pooled means ± standard deviations for SBS to enamel (MPa) were: 10.2±4.2 (Control), 9.7±4.5 (Simultaneous), 5.6±3.1 (One side-20s), and 4.6±1.9 (One side-10s). Pooled SBS data for immediate and thermal cycled groups were 6.3±2.6 and 8.8±5.2. A predominance of ARI scores 1-2 and 0-1 was observed for the immediate and thermally cycled groups, respectively. In conclusion, simultaneous photoactivation of the orthodontic cement using two light-curing units, one positioned at each proximal face of the bracket, yielded similar bonding ability compared to the conventional light-curing method. Photoactivation of the orthodontic cement at one proximal face of the bracket only is not recommended, irrespective of the light-curing time used.</p>

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Effect of Shortened Light-Curing Modes on Bulk-Fill Resin Composites

Operative Dentistry ◽

10.2341/19-101-l ◽

2020 ◽

Vol 45 (5) ◽

pp. 496-505

Author(s):

CS Sampaio ◽

PG Pizarro ◽

PJ Atria ◽

R Hirata ◽

M Giannini ◽

...

Keyword(s):

Tensile Strength ◽

Bond Strength ◽

Shear Bond Strength ◽

Light Output ◽

High Mode ◽

Resin Composites ◽

Curing Time ◽

Micro Computed Tomography ◽

Polymerization Shrinkage ◽

Light Curing

Clinical Relevance Shortened light curing does not affect volumetric polymerization shrinkage or cohesive tensile strength but negatively affects the shear bond strength of some bulk-fill resin composites. When performing shortened light curing, clinicians should be aware of the light output of their light-curing units. SUMMARY Purpose: To evaluate volumetric polymerization shrinkage (VPS), shear bond strength (SBS) to dentin, and cohesive tensile strength (CTS) of bulk-fill resin composites (BFRCs) light activated by different modes. Methods and Materials: Six groups were evaluated: Tetric EvoCeram bulk fill + high mode (10 seconds; TEC H10), Tetric EvoFlow bulk fill + high mode (TEF H10), experimental bulk fill + high mode (TEE H10), Tetric EvoCeram bulk fill + turbo mode (five seconds; TEC T5), Tetric EvoFlow bulk fill + turbo mode (TEF T5), and experimental bulk fill + turbo mode (TEE T5). Bluephase Style 20i and Adhese Universal Vivapen were used for all groups. All BFRC samples were built up on human molar bur-prepared occlusal cavities. VPS% and location were evaluated through micro–computed tomography. SBS and CTS tests were performed 24 hours after storage or after 5000 thermal cycles; fracture mode was analyzed for SBS. Results: Both TEC H10 and TEE H10 presented lower VPS% than TEF H10. However, no significant differences were observed with the turbo-curing mode. No differences were observed for the same BFRC within curing modes. Occlusal shrinkage was mostly observed. Regarding SBS, thermal cycling (TC) affected all groups. Without TC, all groups showed higher SBS values for high mode than turbo mode, while with TC, only TEC showed decreased SBS from high mode to turbo modes; modes of fracture were predominantly adhesive. For CTS, TC affected all groups except TEE H10. In general, no differences were observed between groups when comparing the curing modes. Conclusions: Increased light output with a shortened curing time did not jeopardize the VPS and SBS properties of the BFRCs, although a decreased SBS was observed in some groups. TEE generally showed similar or improved values for the tested properties in a shortened light-curing time. The VPS was mostly affected by the materials tested, whereas the SBS was affected by the materials, curing modes, and TC. The CTS was not affected by the curing modes.

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Microleakage under Orthodontic Brackets Using High-Intensity Curing Lights

The Angle Orthodontist ◽

10.2319/111607-534.1 ◽

2009 ◽

Vol 79 (1) ◽

pp. 144-149 ◽

Cited By ~ 9

Author(s):

Mustafa Ulker ◽

Tancan Uysal ◽

Sabri Ilhan Ramoglu ◽

Huseyin Ertas

Keyword(s):

High Intensity ◽

Light Emitting Diode ◽

Bonferroni Correction ◽

Light Emitting ◽

Halogen Light ◽

Halogen Light Source ◽

Light Curing ◽

Curing Light ◽

High Intensity Light ◽

Nail Varnish

Abstract Objective: To compare the microleakage of the enamel-adhesive-bracket complex at the occlusal and gingival margins of brackets bonded with high-intensity light curing lights and conventional halogen lights. Materials and Methods: Forty-five freshly extracted human maxillary premolar teeth were randomly separated into three groups of 15 teeth each. Stainless steel brackets were bonded in all groups according to the manufacturer's recommendations. Specimens (15 per group) were cured for 40 seconds with a conventional halogen light, 20 seconds with light-emitting diode (LED), and 6 seconds with plasma arc curing light (PAC). After curing, the specimens were further sealed with nail varnish, stained with 0.5% basic-fuchsine for 24 hours, sectioned and examined under a stereomicroscope, and scored for microleakage for the enamel-adhesive and bracket-adhesive interfaces from both the occlusal and gingival margins. Statistical analyses were performed using Kruskal-Wallis and Mann-Whitney U-tests with a Bonferroni correction. Results: The type of light curing unit did not significantly affect the amount of microleakage at the gingival or occlusal margins of investigated interfaces (P >.05). The gingival sides in the LED and PAC groups exhibited higher microleakage scores compared with those observed on occlusal sides for the enamel-adhesive and adhesive-bracket interfaces. The halogen light source showed similar microleakage at the gingival and occlusal sides between both adhesive interfaces. Conclusions: High-intensity curing units did not cause more microleakage than conventional halogen lights. This supports the use of all these curing units in routine orthodontic practice.

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The effect of light curing and self-etching primer after saliva contamination on shear bond strength of orthodontic brackets: An in vitro experimental study

Orthodontic Waves ◽

10.1016/j.odw.2016.11.005 ◽

2017 ◽

Vol 76 (1) ◽

pp. 26-30 ◽

Cited By ~ 1

Author(s):

Farnoosh Fallahzadeh ◽

Ali Tayebi ◽

Soheila Ahmadi ◽

Salva Khosroshahian

Keyword(s):

Experimental Study ◽

Bond Strength ◽

Shear Bond Strength ◽

Orthodontic Brackets ◽

Light Curing ◽

Saliva Contamination ◽

Effect Of Light

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Prototype of a new tip developed to be coupled to dental light-curing units for optimizing bonding of orthodontic brackets and accessories

Dental Press Journal of Orthodontics ◽

10.1590/s2176-94512013000600017 ◽

2013 ◽

Vol 18 (6) ◽

pp. 112-116

Author(s):

Sergio Luiz Mota Júnior ◽

Márcio José da Silva Campos ◽

Marco Abdo Gravina ◽

Marcelo Reis Fraga ◽

Robert Willer Farinazzo Vitral

Keyword(s):

Bond Strength ◽

Shear Bond Strength ◽

Light Exposure ◽

Orthodontic Brackets ◽

Light Refraction ◽

New Device ◽

Halogen Light ◽

Significant Difference ◽

Light Curing

OBJECTIVE: development of a new device to be coupled to light-curing units for bonding orthodontic brackets and accessories, and test its efficacy in an in vitro mechanical trial. The inner surface of the device is mirrored and is based on physical concepts of light refraction and reflection. The main advantage of such device is the reduced clinical time needed for bonding and the low possibility of contamination during the process. METHODS: One hundred and twenty specimens were used for testing the shear bond strength of brackets bonded with the device. The Adhesive Remnant Index (ARI) was also determined. The sample was divided into 2 groups. In group 1 a halogen light-curing unit was used while in group 2 a led light-curing unit was used. Each group was then subdivided. In subgroups H1 and L1, a conventional light guide rod was used while in subgroups H2 and L2 bonding was performed with the mirrored device coupled to the tip of the guide light rod. RESULTS: The values obtained for the shear bond strength and the ARI in the subgroups were compared. Results showed that there was no statistically significant difference for the shear strength (p > 0.05) and the ARI (p > 0.05) between the subgroups. CONCLUSION: The tests of mechanical trials and the ARI analysis showed that the new device fulfilled the requirements for bonding orthodontic accessories, and that the time for bonding was reduced to half, being necessary only one light exposure.

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