Effect of Salivary Pellicle on the Occurrence of Enamel Erosion in vitro

Naše istraživanje je usporedna morfološka studija ultrastrukturnih promjena površine cakline s pelikulom i bez nje. U istraživanju je korištena prizmatska caklina triju humanih impaktiranih molara. Od svakog zuba načinjeno je po 10 uzoraka. Po pet uzoraka svakog zuba stavljeno je na 2 sata u nefrakcioniranu, humanu, parafinskim voskom stimuliranu slinu uzetu od jednog davaoca kako bi se na caklinskoj površini istaložila pelikula. Po dva uzorka svakog zuba, jedan s pelikulom a drugi bez nje, bili su kontrolni, a ostali su stavljeni u zakiseljeni napitak (»Cola« - pH 2,57) u vremenu od 15, 30, 60 i 120 minuta. Uzorci su zatim priređeni za elektronsku mikroskopiju (SEM) i analizirani. Kontrolni uzorci su pokazali da je pelikula nehomogena, »krpasta«, i da ne pokriva potpuno caklinsku površinu. Usporedbom nalaza na caklini s pelikulom i onoj bez nje, općenito se može potvrditi da su erozijske promjene bile znatno manje izražene kod uzoraka s pelikulom bez obzira na vrijeme provedeno u zakiseljenom napitku. Uzorci cakline bez pelikule već su nakon 30 minuta eksponiranosti fosfornoj kiselini pokazivali demineralizacijske promjene središta prizama, a u intervalima od 60 i 120 minuta i periferije prizama i interprizmatske cakline. Kod uzoraka s pelikulom na površini demineralizacijske promjene su viđene samo nakon najdužeg vremena izlaganja kiselini. Slabija otapanja vidljiva su samo u središtu prizama, a na pojedinim uzorcima uočena je i blaga demineralizacija periferije. Dobiveni rezultati potvrđuju hipotezu da salivarna pelikula može zaštititi caklinu od erozijskog djelovanja zakiseljenih napitaka.namel surface with and without pellicle was performed using enamel prisms o f three human impacted molars. Ten specimens were prepared for each tooth. Five specimens of each tooth were immersed into nonfractionated paraffin-vax-stimulated saliva obtained from a donor for 2 h, to allow the pellicle to precipitate over the enamel surface. Two specimens o f each tooth, one with and another without the pellicle, served as controls, whereas other specimens were placed in an acidified beverage (Cola, pH 2.57) for 15, 30, 60 and 120 min. Then, the specimens were prepared for electron microscopy (SEM) and analyzed. Control specimens showed the pellicle to be inhomo geneous, »patchy« and failing to cover the entire enamel surface. Comparison of the findings on the enamel with and without pellicle generally confirmed the erosion alterations to be significantly less pronounced in the specimens with pellicle, regardless o f the time they were left in acidified beverage. The enamel specimens without pellicle showed demineralizing changes of the prism centers as early as after 30 min o f exposure to phosphoric acid, and changes of the prism periphery and interprism enamel after 60 and 120 min, respectively. In the specimens with pellicle on the surface, demineralizing alterations were only observed after the longest period of acid exposure. Minor dissolutions were observed in prism centers only, with mild demineralization of the prism periphery in some of them. The results obtained supported the hypothesis that salivary pellicle could protect the enamel from the erosive action of acidified beverages