Reliability of conventional shade guides in teeth color determination

Abstract

Background/Aim. Color matching in prosthodontic therapy is a very important task because it influences the esthetic value of dental restorations. Visual shade matching represents the most frequently applied method in clinical practice. Instrumental measurements provide objective and quantified data in color assessment of natural teeth and restorations. In instrumental shade analysis, the goal is to achieve the smallest ΔE value possible, indicating the most accurate shade match. The aim of this study was to evaluate the reliability of commercially available ceramic shade guides. Methods. VITA Easyshade spectrophotometer (VITA, Germany) was used for instrumental color determination. Utilizing this device, color samples of ten VITA Classical and ten VITA 3D - Master shade guides were analyzed. Each color sample from all shade guides was measured three times and the basic parameters of color quality were examined: ΔL, ΔC, ΔH, ΔE, ΔElc. Based on these parameters spectrophotometer marks the shade matching as good, fair or adjust. Results. After performing 1,248 measurements of ceramic color samples, frequency of evaluations adjust, fair and good were statistically significantly different between VITA Classical and VITA 3D Master shade guides (p = 0.002). There were 27.1% cases scored as adjust, 66.3% as fair and 6.7% as good. In VITA 3D - Master shade guides 30.9% cases were evaluated as adjust, 66.4% as fair and 2.7% cases as good. Conclusion. Color samples from different shade guides, produced by the same manufacturer, show variability in basic color parameters, which once again proves the lack of precision and nonuniformity of the conventional method.

Uvod/Cilj. Određivanje boje zuba u protetskoj terapiji predstavlja veoma važan zadatak jer utiče na prirodan izgled i estetsku vrednost zubnih nadoknada. Vizuelni metod određivanja boje zuba najčešće se koristi u kliničkoj praksi. Instrumentalna merenja pružaju objektivne i kvantifikovane podatke u proceni boje prirodnih zuba i restauracija. U instrumentalnoj analizi boje cilj je da se postigne najmanja moguća vrednost ΔE, što predstavlja najtačniji izbor nijanse. Cilj ovog istraživanja bio je da se utvrdi pouzdanost najčešće korišćenih ključeva za određivanje boje zuba. Metode. Za instrumentalni izbor boje korišćen je VITA Easyshade spektrofotometar (VITA, Germany). Uz pomoć ovog uređaja, analizirani su uzorci boja 10 VITA Classical i 10 VITA 3D - Master ključeva boja. Svaki uzorak boje analiziran je tri puta i ispitivani su osnovni parametri kvaliteta boje: ΔL, ΔC, ΔH, ΔE, ΔElc. Stepen poklapanje boje nadoknade sa ciljnom nijansom spektrofotometar izražava kroz tri ocene kvaliteta: good, fair i adjust. Rezultati. Nakon izvršenih 1 248 merenja keramičkih uzoraka boje, frekvencije ocena adjust, fair i good statistički su se značajno razlikovale između VITA Classical i VITA 3D - Master ključeva boja (p = 0.002). U VITA Classical ključu boja bilo je 27,1% ocene adjust, 66,3% fair i 6,7% ocene good. U VITA 3D - Master ključu boja bilo je 30,9% ocene adjust, 66,4% fair i 2,7% ocene good. Zaključak. Uzorci boje iz različitih ključeva boja proizvedenih od istog proizvođača, pokazuju varijabilnost u osnovnim parametrima boje, što ukazuje na nepreciznost i neuniformnost konvencionalne metode.