Unit of Endodontology, Departments of Restorative Dentistry, Microbial Diseases, UCL Eastman Dental Institute, University College London, Bloomsbury Campus, Rockefeller Building, 21 University Street, London, WC1E 6DE, UK.
Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, University College London, London, UK.
Clin Oral Investig. 2022 Jul;26(7):5029-5044. doi: 10.1007/s00784-022-04473-2. Epub 2022 Apr 1.
To use extracted human teeth with amalgam (n = 26) or GIC (n = 3) restorations in service up to 20 years to evaluate microbiota at the cavity/restoration interface by SEM or culture.
Extracted teeth with intracoronal restorations (n = 20) of known history (2-20 years) were fixed, split, and prepared for SEM to ascertain the pattern and structure of bacterial aggregates on cavity and restoration surfaces. Another 9 teeth were anaerobically decontaminated, split and sampled (cavity/restorations), and cultured (anaerobically, aerobically); recovered isolates were identified by 16S rRNA gene sequencing.
SEM showed rods, cocci, and filaments in 11/20 teeth (55%) on cavity and corresponding restoration surfaces; 4/20 (20%) on neither surface; 1/20 (5%) on just cavity; and 4/20 (20%) on just restoration. Microbial growth extended from marginal openings into the deeper interfacial microspace to varying extents but was not always evident. Restoration size or age did not predict bacterial presence. Bacteria-free surfaces (cavity/amalgam) showed possible calcification. Cultivation yielded 160 isolates, mainly Gram-positive (86%) and facultative (81%); and morphotypes of rods (43%), cocci (36%), and cocco-bacilli (18%) belonging to Actinobacteria (45%) and Firmicutes (50%). The most frequent genera were Staphylococcus, Streptococcus, Actinomyces, and Lactobacillus. Biofilms on cavity and restoration appeared independent of each other.
Cavity and amalgam surfaces were independently colonised and some not. The penetration of microbiota into marginal gaps varied; resembled root caries and was dominated by Gram-positive species.
Marginal gaps around restorations are unavoidable but are not always colonised by bacteria after long-term clinical service. Calcification of biofilms in the restorative interface may prevent further colonisation. The viable microbiota in the restorative interface resembled root caries and may be subject to ecological fluxes of activity and arrest and therefore preventative management.
使用具有汞合金（n=26）或玻璃离子水门汀（GIC）（n=3）修复体的人离体牙，在 20 年的临床使用期限内，通过扫描电子显微镜（SEM）或培养来评估窝洞/修复体界面处的微生物区系。
固定、劈开并准备具有已知病史（2-20 年）的离体牙（n=20），通过 SEM 来确定细菌聚集体在窝洞和修复体表面的形态和结构。另外 9 颗牙齿进行厌氧消毒，劈开并取样（窝洞/修复体），并进行培养（厌氧、需氧）；通过 16S rRNA 基因测序鉴定回收的分离株。
SEM 显示 20 颗牙齿中有 11 颗（55%）在窝洞和相应的修复体表面上有杆状菌、球菌和丝状菌；4 颗（20%）在两个表面均无；1 颗（5%）仅在窝洞内有；4 颗（20%）仅在修复体上有。微生物生长从边缘开口延伸到更深的界面微空间，但其程度不一，且并不总是明显。修复体的大小或年龄并不能预测细菌的存在。无细菌表面（窝洞/汞合金）显示出可能的钙化。培养获得了 160 个分离株，主要是革兰氏阳性菌（86%）和兼性菌（81%）；形态为杆状菌（43%）、球菌（36%）和类球杆菌（18%），属于放线菌（45%）和厚壁菌门（Firmicutes）（50%）。最常见的属是葡萄球菌、链球菌、放线菌和乳杆菌。窝洞和修复体上的生物膜似乎彼此独立。
窝洞和汞合金表面被独立定植，有些则没有。微生物群渗透到边缘间隙的程度不同；类似于根面龋，以革兰氏阳性菌为主。
修复体周围的边缘间隙不可避免，但在长期临床使用后并不总是被细菌定植。修复体界面处生物膜的钙化可能会阻止进一步定植。修复体界面内有活力的微生物群类似于根面龋，可能会受到活性和停滞的生态变化的影响，因此需要进行预防性管理。
