牙髓炎及根尖周病患牙微生物的超微结构观察

目的扫描电镜观察牙髓炎和根尖周病患牙微生物的超微结构。方法收集健康牙（n=6）、不可复性牙髓炎（n=10）、牙髓坏死（n=20）、慢性根尖周炎（n=20）及难治性根尖周炎（n=6）病例共62例,分为2组,每组各31例,采用扫描电镜观察根管内牙本质面（A组）和根尖周牙骨质面（B组）的微生物形态和定植模式。结果①A组：3例健康牙根管内没有细菌存在;其余28例感染根管内均能观察到被胶状基质包裹的菌落构成生物膜,其中26例（92.9%）可见细菌不同程度侵入牙本质小管;2例难治性根尖周炎样本根管内发现真菌感染。②B组：健康组、不可复性牙髓炎组、牙髓坏死组（共18例）根尖仅见牙周膜胶原纤维网,无细菌生物膜结构;其余13例根尖周炎的患牙均出现根尖骨质吸收纤维破坏以及斑块状根尖生物膜;3例难治性根尖周炎超充牙胶尖表面亦覆盖细菌生物膜。生物膜的超微结构由于基质的多寡和细菌组成不同而表现各异。结论口腔微生物在牙髓炎和根尖周病患牙中主要以生物膜的方式定植,并可侵入牙本质小管或隐匿于牙骨质吸收腔隙中。

Ultrastructure of microorganisms in teeth with pulpitis and periapical periodontitis

Objective To investigate the ultrastrueture of microorganisms in the teeth with pulpitis and periapical periedontitis. Methods The healthy teeth （ n = 6） and the teeth with irreversible pulpitis （ n = 10）, necrotic pulp （ n = 20）, chronic periapical periodontitis （ n = 20 ）, refractory periapical periodontitis （ n = 6） were equally divided into 2 groups to examine the presence of bacteria on the surface of dentin （Group A） and cementum （Group B） by using a scanning electron microscope. Results In Group A, dentin surface of 28 infected root canals covered with dense bacterial aggregates with sticky matrix and among them 26 teeth exhibited microorganisms penetrating into the dentinal tubules, wherase the healthy teeth did not show detectable bacteriun. Fungus infections were found in 2 teeth which were difficult to treat. In Group B, 13 of teeth with periapical periodontitis had root absorption and biofilms formed, while the healthy teeth and the teeth with irreversible pulpitis and necrotic pulp had no these changes. Three teeth with over - filled gutta - perehas were also covered with biofilms. The ultrastructure of biofilm differed from the size of matrix and the composition of bacterium. Conclusion Microorganisms in the teeth with pulpitis and periapical periodontitis were implanted in biofilm and penetrated into the dentinal tubules and hid in the cementum resorption lacunae.