鼻咽癌放疗前后口腔致龋菌丛变化的纵向研究

Bacteria culture of dental plaque and radiation caries of NPC patients before and after radiotherapy

目的 观察鼻咽癌 (NPC)患者放疗前后牙菌斑中的变形链球菌、放线菌及放射性龋临床变化 ,以探讨放射性龋发生的机制。方法 2 2例NPC的患者在放疗前、放疗结束、放疗后 3个月、6个月及 1年取菌斑进行培养 ,观察可培养菌总数的构成比变化及记录变形链球菌数和放线菌数 ,并对患者出现的放射性龋临床症状进行定期观察和记录。结果 NPC患者放疗前牙菌斑与正常人牙菌斑细菌构成在统计学上无差异 ,NPC患者放疗前后牙菌斑的细菌构成比发生显著变化 ,重要致龋菌变形链球菌在放疗后占菌斑可培养细菌百分比随时间的推移而增加 ,放线菌则逐渐下降。临床上放疗早期口干、牙齿酸软症状发生率为 10 0 % ,放疗后 3个月可见牙齿脱钙、龋坏的现象 ,并随时间的推移 ,牙齿脱钙、龋坏现象日益明显 ,6个月到 1年间形成典型的龋洞。结论 放疗后口腔微生态环境的改变 ,特别是牙菌斑中细菌构成变化 ,是导致放射性龋发生的原因之一。

Objective To study the etiopathology of radiation caries.Methods 22 patients with nasopharyngeal cancer (NPC) receiving radiotherapy were included in this study,samples of dental plaque were removed for culture of streptococcus mutans and actinomyces immediately before radiotherapy and after radiotherapy and at 3 mouths,6 mouths and 12 months after its termination.Cultural results were compared with those of 14 healthy people.Oral clinical changes were recorded during the study.Results The component percentage of bacteria was not different between patients before irradiated and healthy people.The component percentage of bacteria of plaque changed in patients after irradiation.Streptococcus mutans increased and Actinomyces decreased significantly step by step.The symptoms of xerostomia and tooth sensitivity were observed.The symptoms of calcipenia and caries were observed at 3 months after radiotherapy,which became worse with time.Conclusion The oral environment changes,especially the of component percentage of bacteria of plaque is one of the reasens for the occurrence of radiation caries.