M Sulieman1, M Addy, E Macdonald, J S Rees. 1. Division of Restorative Dentistry, Department Oral and Dental Science, University of Bristol Dental School, Lower Maudlin St., Bristol BS1 2LY, UK.
Abstract
OBJECTIVES: The aim of the present study was to quantify the penetration of 35% hydrogen peroxide into enamel and dentine and to relate this to the resultant shade change of the tooth. METHOD: The crowns of 24 caries and developmental defect free human maxillary incisors were stained internally with a standardised tea solution. Twelve specimens were power bleached with light activated 35% hydrogen peroxide and 12 placed in water; both exposure times were 30min. Three different shade assessment methods (Vita shade guide [SG], shade vision system [SVS] and a chromometer) were employed prior to, after tea staining and after power bleaching/water treatments. Twelve specimens each from the bleach group and the water control water group were sectioned mesio-distally. An additional 12 specimens from the bleach and the control group were sectioned labio-palatally. The stain area for each specimen was measured using image analysis software. RESULTS: With tea staining, the mean changes in Vita shade guide units (SGU) ranged from 3.66 to 8.33. With the SVS system changes of 3.66-9 units were seen. Chromometer readings showed that following bleaching the L* values moved in the direction of black (3.8-6.7) and a* and b* values were in the red (0.3) and yellow (1.5) direction, respectively. Samples bleached and sectioned mesio-distally showed stain coverage of 28.6-39.4%, while palatal sections showed stain coverage of 58-72%. Control samples, whether sectioned mesio-distally or labio-palatally, showed staining throughout the dentine (97-100% coverage). CONCLUSION: A 35% hydrogen peroxide in-office bleaching gel demonstrated bleaching into dentine of uniform depth.
OBJECTIVES: The aim of the present study was to quantify the penetration of 35% hydrogen peroxide into enamel and dentine and to relate this to the resultant shade change of the tooth. METHOD: The crowns of 24 caries and developmental defect freehuman maxillary incisors were stained internally with a standardised tea solution. Twelve specimens were power bleached with light activated 35% hydrogen peroxide and 12 placed in water; both exposure times were 30min. Three different shade assessment methods (Vita shade guide [SG], shade vision system [SVS] and a chromometer) were employed prior to, after tea staining and after power bleaching/water treatments. Twelve specimens each from the bleach group and the water control water group were sectioned mesio-distally. An additional 12 specimens from the bleach and the control group were sectioned labio-palatally. The stain area for each specimen was measured using image analysis software. RESULTS: With tea staining, the mean changes in Vita shade guide units (SGU) ranged from 3.66 to 8.33. With the SVS system changes of 3.66-9 units were seen. Chromometer readings showed that following bleaching the L* values moved in the direction of black (3.8-6.7) and a* and b* values were in the red (0.3) and yellow (1.5) direction, respectively. Samples bleached and sectioned mesio-distally showed stain coverage of 28.6-39.4%, while palatal sections showed stain coverage of 58-72%. Control samples, whether sectioned mesio-distally or labio-palatally, showed staining throughout the dentine (97-100% coverage). CONCLUSION: A 35% hydrogen peroxide in-office bleaching gel demonstrated bleaching into dentine of uniform depth.
Authors: Diana Gabriela Soares; Ana Paula Dias Ribeiro; Fernanda da Silveira Vargas; Josimeri Hebling; Carlos Alberto de Souza Costa Journal: Clin Oral Investig Date: 2012-12-06 Impact factor: 3.573