engleski

Aesthetic Properties of Composite Dental Materials

Objectives. Composite materials are increasingly being used in anterior aesthetic restorations. In this indication not only color, translucency and opalescence, but also surface gloss is of paramount importance. The purpose of this study was to determine the changes in surface gloss of different composite materials after simulation of mechanical and chemical ageing mechanisms and to evaluate the color stability of modern resin composites designed for esthetic anterior restorations when continuously exposed to various staining agents. Methods. Influence of mechanical and chemical degradation on surface gloss of composite resin materials. Thirty six specimens were fabricated for each material and polished with 120-, 220-, 500-, 1200-, 2400- and 4000- grit SiC abrasive paper, respectively. Gloss measurements were made with a glossometer (Novocurve) prior to testing procedures. Specimens of each material were randomly divided into three groups. First group was conditioned for seven days at 37° C in 75% ethanol aqueous solution. Second was immersed in fluoride gel (Elmex gelée&reg ; ) at 37° C for 1 hour. Third was subjected to simulated toothbrushing with an electrical toothbrush while being immersed in toothpaste. Surface gloss measurements were made subsequently. A spectrophotometric evaluation of susceptibility to staining of composite materials. Six disc-shaped specimens were made of each of twelve composite materials. After dry storage at 37°C for 24 h in an incubator (INP-500, Memmert), initial color of each specimen was assessed by a calibrated reflectance spectrophotometer (SpectroShade). Specimens were then divided in 6 groups and immersed in 5 staining solutions or dry stored (control). All specimens were kept in an incubator at 37°C for 99 days. Test solutions were changed every 14th day to avoid bacteria or yeast contamination. After 99 days of storage spectrophotometric measurements have been again performed and L*a*b* scores once more recorded to determine the color changes. Results. Surface gloss of all the materials was affected by simulated toothbrushing and the decrease of gloss was material dependent. Following immersion in Elmex gelée&reg ; , surfaces of Enamel HFO, Miris 2, CeramX and Clearfill Photo Posterior presented a severe decrease in gloss. There was no significant drop of surface gloss values after 7 days of storage in 75% ethanol. Regarding susceptibility to staining, composite resin materials, staining solutions and their interactions were statistically significant. There was strong interaction between stain and material. Significance. Artificial materials available nowadays try to mimic natural enamels' appearance without reaching a complete success. New developments in nanotechnology, however, let us to imagine that in the future more tooth-like materials could be developed which will present better optical properties and allow enhanced esthetic outcomes. However, color of esthetic restorations can be maintained over a longer period of time in the oral environment either by introducing some restrictions to patient's dietary habits of or carefully choosing the type of material that is best compatible with their dietary lifestyle.

Composite resin; Aesthetic; Surface gloss; Color

Thesis No.670 "Aesthetic Properties of Composite Dental Materials" is a Research Doctorate(not PhD category. The candidate obtained the title Dr.med.dent valid in Switzerland.