A clinical pilot study of the time‐dependent composition of tooth bleaching systems

Abstract

This pilot study was undertaken to determine the compositional changes in tooth bleaching materials as a function of time in vivo. Ten patients were recruited and two bleaching systems were used - one a paste and the other a gel. Each material was placed in a custom bleaching tray and worn by each patient for each of four times - 15, 30, 60 and 120 min. The material was collected and chemically analysed for water by Karl Fischer titration and titrated for carbamide peroxide by the US Pharmacopoeia method. The paste material contained 18.66% water as supplied, and after 2 h this rose to between 28.6 and 64.4%. The gel material contained 2.85% water as supplied, and after 2 h this was diluted to between 28.5 and 73.4%. There was considerable difference in saliva uptake by the custom tray between patients. Most water uptake usually occurred within the first 30 min. Peroxide concentrations decreased in an approximately linear manner with time. There was a significant difference between the materials from baseline to 30 min and thereafter (P < 0.0009). This pilot study is an effective technique for chemical evaluation of bleaching materials. The effect of saliva is an important factor to consider, and is one that has hitherto not always been appropriately emphasized.

Vaginal gel drug delivery systems: understanding rheological characteristics and performance

“…Although there is a lack of information within the scientific literature relating to vaginal gels, this technique has been used to characterize gels used for alternative pharmaceutical applications. In a study by Wille et al [74], creep rheology was used to effectively screen tooth-bleaching materials. Similar to vaginal gels, these materials require ease of application, but should have a high viscosity at low stresses in order to be retained.…”

The effect of artificial saliva on the rheological properties of tooth whitening systems

“…However these studies did not include consideration of the effect of dilution by saliva. The percentage addition of artificial saliva Orthana to Zaris is based on research that showed that at 15 min in the mouth, Zaris contained as an average 20% water (11). For the whitening material Colgate Platinum Overnight (paste), artificial saliva Orthana was added to 30% Orthana, based on the research by Wille et al.…”

“…For the whitening material Colgate Platinum Overnight (paste), artificial saliva Orthana was added to 30% Orthana, based on the research by Wille et al. (11) that showed that at 15 min Colgate Platinum Overnight contained 30% water.…”

“…It is assumed that saliva is a diluting factor that influences the rheology of whitening materials. Most water absorption in vivo by the whitening materials placed in a custom tray occurs during the first 15 min and stays below the 30% level concentration (11). An investigation on the rheological characteristics of whitening materials combined with saliva is needed to determine the behaviour of the mixture once placed in the mouth.…”

Clinical evaluation of a new bleaching product “Polanight” in a Japanese population

“…In the past, there were many investigations of biological factors, such as the effects of the whitening agents on filling materials, [3][4][5][6] hard tooth tissues, 7,8 and oral soft tissues. 9,10 Recently, investigations of environmental factors, such as treatment time, 11,12 comparisons of effects of bleaching gels on oral bacteria, 13 and the effects of tobacco smoking, 14 have also increased. Data on long-term observations have also been accumulated.…”