Oxygen release, microleakage and shear bond strength of composite restorations after home dental bleaching

Authors

  • Marcelo Tomás de Oliveira UNISUL
  • Mauro Amaral Caldeira de Andrade UFSC
  • Márcia Michels Universidade do Sul de Santa Catarina

Keywords:

Bleaching, microleakage, shear, oxygen, carbamide peroxide, composite

Abstract

Purpose: This in vitro study evaluated the effect of home dental bleaching on oxygen release, shear bond strength to enamel, and microleakage of direct composite restorations. Methods: Forty bovine incisors were used for oxygen dissolved titration by means of iodometric methods modified by azide iodine and 26 for the shear bond strength and microleakage tests. For titration the teeth were divided into four groups: T1 - bleached and titrated after 24 h; T2 - bleached and titrated after 48 h; T3 - unbleached and titrated after 24 h; T4 - unbleached and titrated after 48 h. T5 group served as control for the initial oxygen release rate. To analyze shear bond strength and microleakage, the teeth were randomly divided into two groups: CM1 - bleached; CM2 - unbleached. The bleaching agent Opalescence 15% (Ultradent, South Jordan, UT, USA) was applied for 8 h per day for three weeks. Z 250 (3M-ESPE, St. Paul, MN, USA) composite and Single Bond (3M-ESPE, St. Paul, MN, USA) adhesive were used for the composite restoration procedures. Results: There was an increase in oxygen release during the first 24 h post bleaching (ANOVA, P=0.0001). The bleached teeth showed a decrease in shear bond strength (Student’s t test, P=0.0001). The microleakage scores increased with bleaching independently from the examiner (Wilcoxon’s test: 1. P=0.0003; 2 P=0.0023; 3. P=0.0029). Conclusion: Considerable variation was noticed in the results of oxygen release, as well as in the results of shear bond strength and microleakage on bleached teeth.

Author Biographies

Marcelo Tomás de Oliveira, UNISUL

Uraduado pela UFSC em 1990 Mestre em Materiais Dentários PUCRS Doutor em Dentística UFSC Coordenador do grupo de pesquisa em Biomateriais Odontológicos da UNISUL

Mauro Amaral Caldeira de Andrade, UFSC

Departamento de Dentística UFSC

Márcia Michels, Universidade do Sul de Santa Catarina

Laboratório de análise do CENTEC, Universidade do Sul de Santa Catarina (UNISUL), Tubarão, SC, Brasil

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Published

2010-11-29

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Section

Original Article