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dc.contributor.advisorBrunton, Paul
dc.contributor.advisorLyons, Karl
dc.contributor.advisorGray, Andrew
dc.contributor.authorKothari, Siddharth
dc.identifier.citationKothari, S. (2019). Vital Bleaching (At-home, In-office, In-office + At home), Colour Change and Oral Health Related Quality of Life (Thesis, Doctor of Clinical Dentistry). University of Otago. Retrieved from
dc.description.abstractAbstract Objectives This randomised clinical trial compared tooth colour change, participant satisfaction and Oral Health-Related Quality of Life (OHRQoL) following application of at-home, in-office and combined at-home and in-office bleaching treatments. Participants were followed up at 15 days and 3 and 6 months after bleaching. Methods A group of 105 participants was recruited and randomly assigned to receive a combination of at-home and in-office (group A), in-office (group B) or at-home (group C) teeth bleaching treatments. At-home bleaching was performed using custom-made bleaching trays in conjunction with 10% carbamide peroxide (CP) gel for 14 days. In-office bleaching was performed using 37.5% hydrogen peroxide (HP) applied in three cycles, each lasting 8 minutes. The combination of at-home and in-office bleaching treatment involved in-office followed by at-home. Tooth colour change was assessed visually with Vita classical shade guide and using a digital spectromonometer. Participants’ perception of their own oral health, smile and straightness and whiteness of teeth and Oral Health-Related Quality of Life (OHRQoL) were evaluated by means of self-reported questionnaires. Parameters/responses were evaluated/collected prior to bleaching and at every recall visit. Statistical analyses were applied as appropriate to collected data. Significance level (⍺) was set at 5%. Results Change in Colour Combination group treatment resulted in significantly higher shade difference at 15 days recall when assessed using Vita classical shade guide and Spectromonometer (p<0.007). At 3 months recall, participants in group B demonstrated darker teeth compared to the other two groups, measured by visual and digital method (p<0.001). At 6 months there was no difference between groups C and A participants’ teeth colour measured by Vita classical shade guide (p<0.01). Significant improvement to tooth colour was observed among all groups at 6 months recall (p<0.01). Self-perception of oral and dental health and satisfaction with smile and whiteness of teeth was significantly improved following all bleaching protocols (p<0.001). Satisfaction levels with straightness of teeth were significantly improved only in patients younger than 40 years in the combination and in-office bleaching protocols (p<0.012). Change in Oral Health-Related Quality of Life The change in OIDP questionnaires was apparent for the 3- and 6-month follow-up visits (p<0.01), with the frequency of impacts decreasing after the bleaching treatments. The greatest reduction was seen for activities related to laughing and showing teeth without embarrassment, followed by eating and hygiene at the end of 6 months (p<0.01). The changes in the OHIP-aesthetic questionnaires were apparent in the short duration (3 months) (p<0.014), with the greatest improvement in functional, psychological discomfort and handicap (p<0.014). The improvement remained constant during all evaluations. Conclusion Change in tooth colour is faster using the combination bleaching treatment in a short-term period, while in the long-term there is no difference between the combination and at-home teeth bleaching protocols. With the tested bleaching products, in-office treatment should be supplemented with at-home bleaching. Self-perception of OHRQoL is higher for participants in the combination therapy and remained constant during all follow-up visits.
dc.publisherUniversity of Otago
dc.rightsAll items in OUR Archive are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated.
dc.subjectVital Bleaching
dc.subjectTeeth Bleaching
dc.subjectColour change
dc.subjectOral Health Related Quality of Life
dc.subjectQuality of Life
dc.subjectTeeth whitening
dc.titleVital Bleaching (At-home, In-office, In-office + At home), Colour Change and Oral Health Related Quality of Life
dc.language.rfc3066en Rehabilitation of Clinical Dentistry of Otago
otago.openaccessAbstract Only
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