Katherine Karpinia

Single site meta-analysis of 6% hydrogen peroxide whitening strip effectiveness and safety over 2 weeks

OBJECTIVES This research evaluated efficacy and safety of 6% hydrogen peroxide whitening strips from a clinical trials database accumulated over a multi-year period at a single site. METHODS The inclusive meta-analysis involved seven different randomized clinical trials at one dental school. Each study used 6% hydrogen peroxide whitening strips twice daily for 30min over a 2-week period. Common efficacy (digital images) and safety (examination and interview) methods were used across studies. Pooled subject-level data were analyzed using a general linear mixed model to determine overall response and effects of treatment duration on whitening. RESULTS The 148 treated subjects were 18-71 years old, with b* (yellowness) ranging from 12 to 22, and L* (lightness) ranging from 69 to 80. After 1-week strip use, the adjusted mean (S.E.) for Deltab* was -1.6 (0.08), differing significantly from baseline (p<0.0001). After 2 weeks, the adjusted mean (S.E.) for Deltab* was -2.3 (0.07), differing significantly from Week 1 (p<0.0001). The estimated correlation between Weeks 1 and 2 for Deltab* was 0.74. Study-to-study variation contributed less than 2% of Deltab* variability. Results were similar for DeltaL*, with Weeks 1 and 2 estimated means (S.E.) of 1.5 (0.13) and 2.0 (0.12). Occurrence of oral irritation (22%) and tooth sensitivity (20%) did not adversely affect whitening. Other side effects were unremarkable, and only 1 subject (0.7%) discontinued treatment early due to an adverse event. CONCLUSIONS The meta-analysis of multiple studies conducted at a single clinical site over several years establishes consistent, effective and safe vital bleaching with 6% hydrogen peroxide whitening strips.

Clinical comparison of two self‐directed bleaching systems

PURPOSE This randomized clinical trial compared the clinical efficacy and tolerability of 2 marketed self-directed vital tooth-whitening systems. MATERIALS AND METHODS Balancing for baseline tooth color, self-reported coffee/tea use, and age, 57 adult volunteers were randomized to either a whitening strip containing 6% hydrogen peroxide or a tray-based 10% carbamide peroxide/dentifrice/mouth rinse combination system. Following the manufacturers directions, the strip group bleached twice daily for 30 minutes, whereas the tray group bleached twice daily for 20-30 minutes, preceded by tooth brushing with a whitening dentifrice and followed by mouth rinsing with a whitening solution. Treatment extended for 14 days, with evaluation at day 7 and again at day 14. Whitening response was measured objectively as L*a*b* from standardized digital images of maxillary anterior teeth. Tolerability was assessed by oral examination and subject interview. Efficacy comparisons were made using analysis of covariance, whereas tolerability was compared using the nonparametric Wilcoxon rank-sum test. RESULTS Both treatments resulted in statistically significant (P < 0.01) improvements from baseline for all color parameters. For between-group comparisons, the 6% hydrogen peroxide strips yielded a nearly 3-fold reduction in yellowness (deltab*), a nearly 2-fold improvement in lightness (deltaL*), 2.6 times greater redness reduction (deltaa*), and a more than 2-fold change in overall color (deltaE*) compared to the tray-based combination system. Between-group comparisons were statistically significant for the all color parameters at both the day 7 and day 14 evaluations (P < 0.001). In general, 7-day use of the whitening strips provided significantly greater color improvement relative to the combination dentifrice/gel/rinse system at day 14. In addition, the groups differed significantly (P < 0.05) in bleaching tolerability severity-days, with the strip system demonstrating better overall tolerability compared to the combination system. CONCLUSIONS The single-step 6% hydrogen peroxide strips demonstrated better overall clinical response, in terms of both tooth-whitening efficacy and tolerability, than the multiple-step tray-based combination system.

An algometer for intraoral pain tolerance measurements

An algometer was developed to provide a variable probing force (0-200 g force) which could be used intraorally. This algometer consisted of an autoclavable probe handpiece attached to an optical encoder, which recorded probing force to a computer when a button was pressed. The probe handpiece included a 0.40 mm diameter hemispherical tip which was placed in contact with the experimental site. The probe tip was pressed against the tissue with increasing force until the subject pressed the button, at which point the pain tolerance (PT) value was recorded by the computer. Intraoral soft tissue, PT values were obtained from nine healthy adult subjects during 6 weekly visits to determine the reproducibility of PT measurements. Five gingival sulcus sites and three gingival surface sites, all adjacent to the maxillary premolars constituted the experimental area. The reproducibility of PT values using the force stimulus from the algometer was evaluated using interclass correlation coefficients (R) for each of the eight sites. Visits 1 and 2 were training and calibration visits. Visits 3 through 6 were experimental visits. The R values ranged from 0.40 to 0.79 when data from all six visits were included. R values for Visits 3 through 6 were 0.63-0.97 indicating good to excellent correlation after subjects became familiar with the procedure. A complete repeated measures analysis of variance (ANOVA) showed no significant interaction between site and visit. Duncans multiple range test was used to compare sensitivity across the eight sites. The results indicated that the three most anterior sites were significantly (P < 0.05) more sensitive than four of the posterior sites. When the sites were grouped into: (1) gingival surface sites; (2) mid-facial sulcus sites; and (3) interproximal sulcus sites, no significant differences were found in their PT values. The algometer is well suited for intraoral investigations because of its precision, computerized data entry and easily positioned, autoclavable handpiece. This new algometer may be useful for sensory and pain studies for other parts of the body.

Recent approaches to periodontal therapy.

Periodontal diseases encompass a variety of disease classifications, all involving inflammation of the supporting tissues of the teeth. When progressive, these diseases ultimately lead to the destruction of attachment apparatus including bone and periodontal ligament, culminating in eventual tooth loss. Inflammation extends from superficial gingival structures, effecting adjacent submerged bone and periodontal ligament. Progression modifies an initially highly favourable, reversible diagnosis of gingivitis to a less favourable, somewhat irreversible situation: periodontitis. Periodontal diseases manifest variable and sometimes unpredictable prognoses, are generally somewhat complicated and costly to treat and often require long-term follow-up for maintenance and monitoring. Treatment aims at restoration of health and control of future disease within a functional, albeit reduced, periodontium. In the strictest sense, periodontal diseases are not ‘cured’. The conventional, usually successful, approach to the treatment of patients with gingivitis or chronic periodontitis has involved non-surgical mechanical periodontal therapy [1,2]. Some patients manifest localised or generalised continuous attachment loss and periodontal destruction. These sites are prime candidates for alternative therapeutic regimens. This review highlights some of the recent advances in periodontal therapy and evokes some questions that should be addressed during future studies.