Clinical and microbiological features of subjects with adult periodontitis who responded poorly to scaling and root planing

Abstract In a previous report, it was shown that scaling and root planing (SRP) decreased mean pocket depth and attachment level in subjects with adult periodontitis, as well as the levels and prevalence of Bacteroides forsythus, Porphyromonas gingivalis and Treponema denticola. However, a subset of subjects in that study exhibited mean loss of attachment following SRP. The purpose of the present investigation was to seek clinical and microbiological differences between subjects who responded well or poorly to SRP. 57 subjects with adult periodontitis were treated by full-mouth SRP under local anaesthetic. Clinical assessments of plaque, redness, suppuration, BOP, pocket depth and attachment level were made at 6 sites per tooth prior to and 3 months post-SRP. Attachment level measurements were repeated at each visit and differences in means between visits used to assess change. 18 subjects showed mean attachment loss 3 months post-SRP (poor response group), while 39 showed mean attachment level gain (good response group). The prevalence and levels of 40 subgingival taxa in subgingival plaque samples from the mesiobuccal site of each tooth (maximum 28 sites) in each subject prior to and 3 months post-SRP were assessed using checkerboard DNA-DNA hybridization. The prevalence of each species was computed for each subject and averaged across subjects in the 2 treatment-response groups at each visit. Differences between groups were sought using the Mann-Whitney test. There were no statistically significant differences between the 2 response groups in any clinical parameter prior to therapy. Subjects in the good response group showed more attachment level gain at sites with baseline pocket depths of < 4 mm, 4–6 and > 6 mm than poor response subjects. Of 40 species evaluated. A. naeslundii genospecies 2 (A. viscosus), T. denticola, C. gracilis and C. rectus were significantly higher and more prevalent pre-therapy in the good response subjects. Mean attachment level change post SRP could be predicted using multiple linear regression with A. naeslundii genospecies 2 (A. viscosus) and T. denticola as the predictor variables (r²=0.373, p < 0.00001). Sites that gained ≥ 2 mm of attachment post therapy showed a significant decrease in the counts of P. gingivalis (7.5±3.5 to 0.2±0.2×10⁵), T. denticola (8.2±3.5 to 1.8±1.1×10⁵) and B. forsythus (11.1 ± 5.7 to 0.3±0.2×10⁵). The data of the present investigation indicate that SRP is most effective in subjects and sites with high levels of the subgingival species that this therapy affects.     

Subgingival biodiversity in subjects with uncontrolled type‐2 diabetes and chronic periodontitis

Background and Objective: There is a bidirectional relationship between periodontal disease and type‐2 diabetes mellitus (DM). Inflammatory mediators may negatively affect glycemic control, and increased glucose levels and resultant glycation end‐products may alter the host response against bacterial infection. However, no agreement has been reached regarding the effect of DM on periodontal subgingival microbiota. Therefore, the purpose of the present study was to compare the subgingival biodiversity in deep periodontal pockets of subjects with chronic periodontitis and either uncontrolled type‐2 diabetes or no diabetes using 16S rRNA gene cloning and sequencing. Material and methods: Twelve subjects with uncontrolled type‐2 diabetes (glycated hemoglobin > 8%) and eleven nondiabetic subjects presenting severe and generalized chronic periodontitis were selected. Subgingival biofilm from periodontal pockets > 5 mm were assessed using the 16S rRNA gene cloning and sequencing technique. Results: Significant differences were observed in subgingival microbiota between diabetic and nondiabetic subjects. Diabetic subjects presented higher percentages of total clones of TM7, Aggregatibacter, Neisseria, Gemella, Eikenella, Selenomonas, Actinomyces, Capnocytophaga, Fusobacterium, Veillonella and Streptococcus genera, and lower percentages of Porphyromonas, Filifactor, Eubacterium, Synergistetes, Tannerella and Treponema genera than nondiabetic individuals (p < 0.05). Moreover, some phylotypes, such as Fusobacterium nucleatum, Veillonella parvula, V. dispar and Eikenella corrodens were detected significantly more often in diabetic subjects than in nondiabetic subjects (p < 0.05). Conclusion: Subjects with uncontrolled type‐2 diabetes and chronic periodontitis presented significant dissimilarities in subgingival biodiversity compared with nondiabetic subjects.     

Implantation of Candida albicans and other Candida species in the oral cavity of rats

The carriage of five Candida species in the mouths of normal and siaioadenectomised rats was determined for periods up to 30 days after inoculation into the oral cavity. In both test and control animals. Candida albicans was the species recovered in greatest quantities at all periods, followed by C. parapsilosis and C. tropicalis. In contrast. C. gullliermondii and C. krusei were isolatable only in small numbers and only from the 1st up to the 5th day; they were not present thereafter. Sialoadenectomy favoured oral colonisation only by C. albicans ( P <0.05) and did not influence the carriage of the other species.