Choice of toothpaste for the elderly: an in vitro study

Hyposalivation and dental root exposure in the elderly are problems that require special oral care. In this context, the characteristics of certain toothpastes are of particular importance. Thus, the aim of this study was to evaluate the cytotoxicity and dentin wear caused by seven different toothpastes. For dentin wear analysis, 40 root dentin specimens were submitted to 20,000 brushing cycles with the different toothpastes and distilled water (control group-CG), using a brushing machine. Dentin surface loss (SL) was measured by contact profilometer. The cytotoxicity of each toothpaste was tested using cultured fibroblasts submitted to a cell-culture-conditioned medium. Fresh medium served as the control. Cell viability was assessed by MTT assay after 24 h of contact with the conditioned media. The data were analyzed statistically by ANOVA, followed by Tukey’s test (p < 0.05). The SL of the CG was minimal and significantly lower than that of the Oral B Pro Health (OBPH) group (p < 0.05). All other groups presented SL in between that of the CG and the Oral B Pro Health OBPH group, except for the Sensodyne (SEN) group, which presented SL similar to that of CG (p = 0.05). The SEN group presented a percentage of viable cells similar to that of CG: between 60-89%. All the other toothpastes showed high cytotoxicity, with cell viability less than 50% of the CG. Considering study limitations, we concluded that only one of the seven tested toothpastes exhibited the most desirable toothpaste characteristics for the worldwide growing elderly population (e.g. low cytotoxicity and low-abrasive potential).

老年人唾液分泌减少与牙根暴露均为需特殊口腔护理的临床问题。在此背景下，特定牙膏的性能特征尤为关键。为此，本研究旨在评估7款受试牙膏所引发的细胞毒性与牙本质磨耗情况。针对牙本质磨耗分析，本研究借助刷牙机，将40份牙根牙本质标本分别用7款受试牙膏及蒸馏水（对照组CG）进行20000次刷牙循环处理，采用接触式轮廓仪测量牙本质表面缺损（Surface Loss，SL）。针对细胞毒性评价，本研究采用经牙膏条件培养液孵育后的成纤维细胞开展实验，并以新鲜培养液作为空白对照。将成纤维细胞与条件培养液共同孵育24小时后，采用MTT法检测细胞存活率。数据采用单因素方差分析（ANOVA）进行统计学分析，随后采用Tukey检验进行多重比较，检验水准设定为p<0.05。结果显示，对照组CG的牙本质表面缺损量最低，且显著低于欧乐B健康护龈（Oral B Pro Health，OBPH）组（p<0.05）；其余受试组的缺损量均介于CG组与OBPH组之间，仅舒适达（Sensodyne，SEN）组的缺损量与CG组无显著差异（p=0.05）。SEN组的细胞存活率与CG组相近，为60%~89%；其余所有牙膏均表现出较高细胞毒性，细胞存活率仅为CG组的50%以下。结合本研究的局限性，研究团队最终得出结论：针对全球日益增长的老年人口群体，7款受试牙膏中仅1款具备最理想的性能特征，即低细胞毒性与低磨耗潜能。