Paini Thais R D, Uchimura Joana Y T, Sato Francielle, Medina Neto Antonio, Shimauti Eliana L T, Baesso Mauro L, Hidalgo Mirian M, Dos Santos Marcia L A, Previdelli Isolde T S, Pascotto Renata C
Department of Dentistry, State University of Maringa, Maringá, PR, Brazil.
Department of Physics, State University of Maringa, Maringá, PR, Brazil.
Clin Cosmet Investig Dent. 2022 Apr 28;14:103-112. doi: 10.2147/CCIDE.S361230. eCollection 2022.
The use of discolored teeth is required to test whitening products, and it is difficult to obtain them, given their scarcity.
To present a technique for in vitro darkening of extracted teeth simulating pulpal necrosis discoloration.
Hemolysates I and II from human blood were subjected or not to laser irradiation (442 nm) for 1 h. The concentration of oxyhemoglobin (OHb) was analyzed by ultraviolet/visible spectroscopy, and the conversion of OHb 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%).
HSII+L presented the lowest OHb and higher MetHb. The conversion of OHb 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.
The proposed technique was effective in darkening the extracted teeth simulating necrosis discoloration for in vitro models.
测试美白产品需要使用变色牙齿，但由于其稀缺性，很难获得。
介绍一种体外使拔除牙齿变黑以模拟牙髓坏死变色的技术。
将人血的溶血产物I和II分别进行或不进行1小时的激光照射（442nm）。通过紫外/可见光谱分析氧合血红蛋白（OHb）的浓度，并通过透射光谱评估OHb向高铁血红蛋白（MetHb）的转化，分别在即刻、3天和40天后进行评估。为了评估牙齿变黑情况，将牛切牙分为两组（n = 25），其髓腔分别填充溶血产物溶液II（HSII）和溶血产物II溶液+激光（HSII+L）。在37°C下于人工唾液中储存40天后，用色差仪测量颜色变化，并将ΔE与NBS参数进行比较。使用混合线性模型（α=5%）分析数据。
HSII+L组的OHb最低，MetHb较高。HSII+L组中OHb向MetHb的转化率比HSII组高42%。根据NBS标准，两组均能有效使牙齿变黑。牙齿变黑在第35天趋于稳定。HSII组导致明显的颜色差异。
所提出的技术对于体外模型中模拟坏死变色使拔除牙齿变黑是有效的。
