Bevenius J, Linder L, Hultenby K
Department of Clinical Oral Science, Karolinska Institutet, Stockholm, Sweden.
Acta Odontol Scand. 1994 Oct;52(5):294-302. doi: 10.3109/00016359409029042.
Scanning electron (SEM) microscopy of epoxy replicas made from dental impressions has shown that in buccal gingival recession the root surfaces are devoid of cementum, leaving the dentin exposed. In this study replication techniques were applied to correlate the micromorphology of the buccocervical region with early streptococcal attachment. The subjects were 27 healthy young adults. The buccocervical surfaces of all the premolars were meticulously cleaned. The subjects fasted for 2 h before impression-taking. Replicas were made from impressions in hydrophilic A-silicone, and streptococcal attachment was visualized by light microscopy of mitis-salivarius agar replicas incubated anaerobically for 48 h. The surface micromorphology was documented by SEM of corresponding epoxy replicas. Colonization only 2 h after cleaning was very sparse. Sites with healthy or inflamed gingivae had markedly different colonization patterns in the sulcular region. In 4 subjects with a total of 12 sites where gingival recession, undetected clinically, was disclosed by SEM, representative colonies were retrieved and identified microbiologically to species level. Two healthy sites per subject were also sampled. Streptococcus mutans and S. sobrinus were identified from eight sites with exposed root dentin. S. oralis predominated on the enamel surfaces. The method offers a valuable complement to in situ and in vitro microbiologic studies of exposed dentin and a novel technique for sampling clinical isolates of streptococci.
对牙科印模制作的环氧树脂复制品进行扫描电子显微镜（SEM）观察发现，在颊侧牙龈退缩处，根面无牙骨质，牙本质暴露。在本研究中，应用复制技术将颊颈区域的微观形态与早期链球菌附着相关联。研究对象为27名健康的年轻成年人。所有前磨牙的颊颈表面均被仔细清洁。受试者在取印模前禁食2小时。用亲水性A-硅橡胶印模制作复制品，并通过对在厌氧条件下培养48小时的变形链球菌琼脂复制品进行光学显微镜观察来观察链球菌的附着情况。通过相应环氧树脂复制品的SEM记录表面微观形态。清洁后仅2小时的定植非常稀疏。健康或发炎牙龈部位在龈沟区域有明显不同的定植模式。在4名受试者中，通过SEM发现了临床上未检测到的牙龈退缩，共12个部位，从中获取代表性菌落并进行微生物学鉴定至种水平。每个受试者还选取两个健康部位进行采样。在8个暴露根牙本质的部位鉴定出变形链球菌和远缘链球菌。口腔链球菌在釉质表面占主导地位。该方法为暴露牙本质的原位和体外微生物学研究提供了有价值的补充，也是一种采集链球菌临床分离株的新技术。
