Comparison of short term effectiveness of four different tooth whitening systems.
- Report, and compare, the short term effectiveness and major side effects of 4 different bleaching systems in a relatively large sample representing the general public.
- Investigate if combination treatment ( office + home ) gives better bleaching effect than using either of the methods alone.
- To assess the patient satisfaction level of bleaching treatments.
Material and methods:
- Subjects with active periodontal problems, carious lesion, broken/fractured teeth or restorations, missing anterior tooth, or with restoration covering more than 30% of labial surface of any anterior tooth, or exposed dentin.
- Subjects with amelogenesis, dentogenesis imperfecta, or other dental anomalies affecting the outer tooth surface.
- Subjects with history of previous bleaching treatment or active orthodontic treatment.
- Pregnant or lactating females.
- Home bleaching (HB) group:(Opalescence 20%, Ultradent Products Inc, South Jordan, Utah USA).
- Brightsmile (BS) group: Light activated in-office bleaching systems (BRITESMILE 2000, Discus Dental, Culver city, California, USA).
- Zoom (Z) group: Light activated in-office bleaching systems ( Discus Dental, LLC., Culver city, California, USA).
- Zoom plus home bleaching (Z+HB) group: Light activated in-office bleaching systems (ZOOM 3) combined with home bleaching system (Day White 9.5%, Discus Dental LLC., Culver city, California, USA).
To avoid the subjective variation and bias, the clinical examination was done by two calibrated dentists (FK and JA). Prior to starting the study, our whitening effect evaluators were calibrated to use the vita shade guide in the following way:
An acceptable kappa score (substantial agreement, 0.61-0.80) was ascertained 26. Calibration for the subjective discrepancies regarding the reading of the shade guide was done by making the analyzers read the shade on 18 ceramic tooth models randomly picked. The analyzers were provided with the same models a week later and their readings were documented again. The difference between the two trail readings were analyzed and Kappa score was calculated within each examiner and between both examiners. This calibration was repeated until accepted kappa score was obtained. The intra-examiner consistency by kappa for examiner FK was 0.73 and for examiner JA was 0.98. The inter-examiner consistency kappa between the 2 examiners was 0.80.
Whitening effect: The whitening effect was assessed at the middle third of the labial surface of the upper right central incisor. The whitening effect was measured before bleaching (T0), 1 to 3 days post bleaching (T1), and 3months ( + or – 1 week) after bleaching (T2). The whitening effect was evaluated by the following methods:
1. Self-evaluation by the patient: A 10 cm long Visual analog scale divided into 1cm long segments (scaled form 0 to 10 with 10 as very dark teeth, 5 as normal or acceptable whiteness, and 0 as excellent whiteness) was presented to each subject at each evaluation interval to determine the brightness of the subject's right upper central incisor (fig. 1).
fig. 1: Visual Analog
Care was taken to ensure that subject’s lips were not covered with any lip stick at any evaluation time. The evaluation was conducted in a well lit room without use of dental chair light. The subject would evaluate the shade of his/her teeth by looking in a non-magnifying hand mirror.
2. Clinical evaluation by calibrated dentist: Vita 3D bleached shade guide was used at each evaluation interval to determine the shade of the upper right central incisor. The examination was done by two calibrated dentists (FK and JA). The lightest tab of the vita 3D bleached shade guide (0M1) was marked as 0 and the darkest tab (5M3) as 14 (fig. 2).
fig. 2: Vita 3D Bleached Shade Guide
Patient perception regarding tooth sensitivity and gingival irritation was evaluated by questioning the subjects at T0, T1, and T2 if their teeth were sensitive at all times or sensitive to hot, cold, chewing, or brushing. The response of the patient was marked 0 if no sensitivity was present, 1 if mild sensitivity was present, 2 if moderate to severe sensitivity was present. Similarly, The subjects were asked if they experienced any gingival sensitivity. The response of the patient was marked 0 if no sensitivity was present, 1 if mild sensitivity was present, 2 if moderate to severe sensitivity was present. The responses of all questions related to sensitivity of teeth and gingiva were combined and then the mean of the overall responses was calculated
Treatment satisfaction level:
Patient satisfaction level was assessed by questioning the participants at T1 and T2 if they would repeat the bleaching procedure again and if they would recommend the bleaching procedure to a friend. The response of the subjects were marked as 0 if their answer was “no”, and 1 if their answer was “yes”.
Data management and analysis were carried out using the Statistical Package for Social Sciences Software (SPSS, version 17.0; SPSS Inc., Chicago, Ill., USA). The variables age and whitening scores were examined for normality of data with Kolmogorov-Smirnov test, and descriptive statistics presented as mean and standard error (SE). The whitening effect evaluators were calibrated to use the vita shade guide by kappa values. The differences in initial values, T0 and subsequent follow up at T1 and T2 were compared using non-parametric Mann-Whitney- or Kruskal Wallis tests. The proportional responses on sensitivity to various bleaching methods, and their severity were assessed with Chi-square or normal Z-test. The two-tailed probability p value < 0.05 was considered statistically significant.
|Table 1: The mean whitening scores in 4 types of bleaching methods by 2 different evaluation methods at T0 and T1|
|Table 2: The mean whitening scores in 4 types of bleaching methods by 2 different evaluation methods at T0 and T2|
Table 3: The number of subjects and the tooth sensitivity and gingival irritation for the 4 bleaching methods at T0, T1, and T2
Table 4: The number of subjects (%) who were satisfied and would repeat the bleaching procedure or recommend the procedure to a friend, according to bleaching method at T1 and T2.
Modern dentistry has witnessed the emergence of many bleaching methods and materials. In pursuit of better shade for vital teeth, bleaching remains one of the most preferred economically viable and conservative treatments4. The manufactures of different bleaching systems claim superior efficacy of their bleaching systems compared to others. Since the active ingredients of most bleaching systems is the same, the authors of this study attempted to report if any differences exist among 4 popular bleaching systems with regard to efficacy and major side effects in a relatively large sample.
Unlike previous studies5, 9, 11-15, 24, 25 which excluded subjects with initial tooth shade lighter than D4, this study did not exclude any patients whose initial shades were relatively lighter on the vita shade guide. We accepted all patients who walked in with dark teeth complaint or with a feeling that their teeth were not as white as they should. We believe that including such patients will make our sample more representative to the actual population. If the sample is skewed toward only those with darker teeth, the effectiveness of the bleaching methods could be overestimated.
In order to assure best reliability of the results, 2 evaluation methods were used. The patients used 10 cm long visual analog scale divided into 1cm long segments and the dentists used Vita 3D bleaching shade guide in their assessments of the whitening effects. Both evaluation methods showed that all of the four bleaching systems were equally effective at T1 and T2. Contrary to what was expected 16-18, the combination of in-office bleaching with home bleaching was not more effective than in-office bleaching alone or home bleaching alone. However, this study was limited to short term effectiveness, up to 3 months (+ or – 2 weeks) after the date of the bleaching. The sample used in this study will be followed to test if there will be any long term differences in the effectiveness among the 4 bleaching systems, which will be reported in future studies.
Confirming the results of the other studies 8, 13 -15, 19-21 there was a significant increase in the tooth and gingival sensitivity immediately after bleaching at T1. The results of this study further reinforces the fact that tooth sensitivity associated with any bleaching method is transient. The responses of the subjects to the sensitivity questions at T2 showed no significant differences than their responses to the same sensitivity questions at T0
The satisfaction level of the patients who participated in this study was assessed by their positive response to the questions about their bleaching or their recommendation bleaching to their friends. The significant increase in teeth whitening at T1 and T2 combined with relatively minor and transient tooth and gingival sensitivity seemed to make the majority of the subjects satisfied with the overall tooth whitening results. However, it should be emphasized that treatment satisfaction could be influenced by many variables such as the ambience of a dental office and behavior of the staff which could not be controlled in this study.
1) The whitening systems tested in this study are all effective (short term) with no significant difference between them.
2) There is transient increase in tooth and gingival sensitivity as a result of tooth whitening treatment.
3) The combination of home bleaching with in-office bleaching is not more effective than either alone
4) Patient satisfaction level for tooth whitening procedure is high
Dentists could choose any of the whitening systems which were tested in this study because they are equally effective with self-limiting side effects.
The authors wish to thank Fabi Koya for her assistance in clinical investigation and data collection. This work was supported by Kuwait University Research Administration grant DI 02/06.
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