Bauru School of Dentistry, University of São Paulo, Al. Octávio Pinheiro Brisola, 9-75, 17012-901 Bauru, SP, Brazil.
Department of Dentistry, State University of Ponta Grossa, Av. General Carlos Cavalcanti 4748, 84030-900 Ponta Grossa, PR, Brazil.
Toxicol In Vitro. 2018 Oct;52:8-13. doi: 10.1016/j.tiv.2018.05.012. Epub 2018 May 25.
The coadjutant method for denture cleansing most used by denture wearers is immersion in chemical agents, which are toxic when in direct contact with cells. However, clinically, the contact between these chemical agents and prosthetic tissues does not occur directly, but rather with what remained impregnated into acrylic bases, even after rinsing the disinfected dentures. This study evaluated the antimicrobial and cytotoxic effects of a denture acrylic resin after successive cycles of daily overnight immersion in 1% sodium hypochlorite (1%NaClO) and 2% chlorhexidine digluconate (2%CHX), simulating the periods of 9 months or 1.5 year. Microbiological and cytotoxic assays were performed, respectively, by broth microdilution method (Candida albicans or Staphylococcus aureus) and MTT assay. Chemical residues of 2%CHX impregnated into the denture acrylic resin had an antimicrobial effect on both immersion periods, which was not observed with those of 1%NaClO. However, residues of 2%CHX were severely cytotoxic to human gingival fibroblasts compared to those of 1%NaClO and acrylic resin (not submitted to the denture cleansers), which were slightly cytotoxic. Even at low concentrations recommended for overnight soaking of removable dentures, the chemical residues of CHX may result in some degree of toxicity to the denture-bearing mucosa after long-term daily immersion.
义齿清洁的辅助方法是将义齿浸泡在化学制剂中，这些化学制剂直接接触细胞时是有毒的。然而，在临床实践中，这些化学制剂与义齿组织之间的接触并不是直接的，而是与残留的、已经浸渍到丙烯酸基托中的物质接触，即使对经过消毒的义齿进行了冲洗也是如此。本研究评估了义齿丙烯酸树脂在每天隔夜浸入 1%次氯酸钠（1%NaClO）和 2%葡萄糖酸氯己定（2%CHX）中连续循环后的抗菌和细胞毒性作用，模拟 9 个月或 1.5 年的周期。分别通过肉汤微量稀释法（白色念珠菌或金黄色葡萄球菌）和 MTT 测定法进行微生物学和细胞毒性测定。在两个浸泡周期中，2%CHX 浸渍到义齿丙烯酸树脂中的化学残留物都具有抗菌作用，而 1%NaClO 则没有。然而，与 1%NaClO 和丙烯酸树脂（未经过义齿清洁剂处理）相比，2%CHX 的化学残留物对人牙龈成纤维细胞具有严重的细胞毒性，而 1%NaClO 和丙烯酸树脂的细胞毒性则较小。即使是推荐用于可摘义齿隔夜浸泡的低浓度，CHX 的化学残留物在长期每日浸泡后也可能对义齿承托的粘膜造成一定程度的毒性。
