Abrazivita zubnich past. Prispevek k metodice hodnoceni abrazivity podle soucasnych pozadavku mezinarodnich norem.

Toothbrush and toothpaste are two basic aids in the individual oral hygiene. The demand of more frequent and longer lasting toothbrushing bears the risk of unfavourable effect of this procedure to dental hard tissues. The cleaning efficacy of toothpastes is given to a considerable extent by the mechanical effect of their abrasive components. Abrasive materials used in toothpastes formulas are to fill lots of hygiene demand, among which the defined hardness, size and shape of abrasive particles are of utmost importance. These characteristics significantly influence both the cleaning ability and, on the contrary, the risk of the impairment of dental hard tissues. With regard to the fact that there have not been so far difened criteria of the toothpastes abrasivity evaluation, we attempted to design appropriate methods and evaluation technologies. For this purpose a new device for testing surface wear in model dental tissues (dentin, enamel) and reference standard (ivory) was developed. The results gained can be summarized as follows: Experiments in vitro showed that the abrasivity of toothpastes is not only the function of abrasive components but the result of demanding interaction of liquid and firm components of toothpastes with the surfaces of hard dental tissues; the results gained depend on methods employment and their sensitivity. Laboratory tests prove, when profilometric measurements and mass wear of metallic bodies were taken into account, that the efficacy of abrasive components declines between carbonates, zeolites, phosphates and PVC; Developed toothpastes containing PVC showed equal abrasive efficacy to those containing phosphate abrasives. Among developed toothpastes with increased cleaning properties (for smokers) the highest abrasive efficacy and the best cleaning property showed No. 58/81 toothpaste. The abrasive efficacy of toothpastes of Czech producers declines between Sotenal, Fluora, Carlotherm, Evodent, Extradent and Elmex. Based on the results of evaluating the properties of abrasive ingredients and toothpastes, the parameters of abrasive processes in the system toothpaste-toothbrush-dental hard tissue in vitro were refined for more exact modelling the abrasive processes in dental tissues in vivo. For better modelling the abrasive process in vivo, a new brushing machine was designed and employed. This design was used for evaluating the abrasive efficacy of both local and foreign toothpastes and their effect was evaluated profilometrically on dentin and ivory. The most pronounced changes were shown on both surfaces in silicate abrasives containing toothpastes (Colgate tartar control, AC 35). The dentin surface was more influenced by toothpastes with carbonate abrasives (standard, Fluora) that by those containing phosphates (Odol, Thymolin sensitive, Sensodyne F). Some exceptions seen in Stoma TTO and Thymolin perfect can be explained by different content and characteristics of abrasive particles. Differences shown between changes on the surface of dentin and ivory caused by carbonate and phosphate containing toothpastes can be additionally explained by different structural arrangement of these hard tissues. Sequentionally entering into force, international norms for evaluating the properties of toothpastes have increased demand on the reliability of abrasion testing systems and on detection methods. With regard to the above norms admitting the employment even of comparably sensitive and reproducible methods, the original radioindication method was developed and ascertained for this purpose.Available from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi