Technique for Darkening of Extracted Teeth Simulating Pulpal Necrosis Discoloration.

Abstract

BackgroundThe use of discolored teeth is required to test whitening products, and it is difficult to obtain them, given their scarcity.ObjectiveTo present a technique for in vitro darkening of extracted teeth simulating pulpal necrosis discoloration.Materials and MethodsHemolysates I and II from human blood were subjected or not to laser irradiation (442 nm) for 1 h. The concentration of oxyhemoglobin (O2Hb) was analyzed by ultraviolet/visible spectroscopy, and the conversion of O2Hb to methemoglobin (MetHb) by transmission spectroscopy was assessed immediately and after 3 and 40 days. For darkening evaluation, bovine incisors were divided into two groups (n = 25), and their pulp chambers were filled with hemolysate solution II (HSII) and hemolysate II solution + laser (HSII+L). After storage in artificial saliva for 40 days at 37°C, color changes were measured by a colorimeter and ΔE was compared with the NBS parameters. Data were analyzed using a mixed linear model (α=5%).ResultsHSII+L presented the lowest O2Hb and higher MetHb. The conversion of O2Hb to MetHb in HSII+L was 42% higher than in HSII. Both groups were effective in darkening the teeth, according to the NBS. Darkening stabilized from day 35. HSII promoted a marked color difference.ConclusionThe proposed technique was effective in darkening the extracted teeth simulating necrosis discoloration for in vitro models.