摘要:

The purpose of the present study was to determine the surface hydrophobicity of small oral spirochetes and to receive an impression of the molecular organization of the cell surfaces. Nine spirochete strains with one endoflagellum from each cell-end (1:2:1 spirochetes) and eight with two endoflagella from each cell-end (2:4:2 spirochetes) from subgingival plaque were examined. Two hydrophobicity assay systems were used: 1) two-phase partitioning and 2) salting-out aggregation by ammonium sulfate. The influence of heat, enzymes, saliva, and serum were examined. The 2:4:2 spirochetes were significantly more hydrophobic than the 1:2:1 spirochetes. For all strains heat treatment increased surface hydrophobicity, whereas incubation with proteases decreased surface hydrophobicity for the 1:2:1 spirochetes. The 2:4:2 spirochetes were unaffected by the proteases. Lipase and hyaluronidase affected the two morphotypes in opposite directions. Saliva did not affect the surface hydrophobicity of any of the strains, whereas rabbit serum decreased this property for the 2:4: 2 strains.

ISSN:0001-6357    

DOI:10.3109/00016359109041134

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The pain experienced after 116 operative removals of mandibular third molars was studied in a homogeneous group of patients consisting of 85 healthy university students. Pain was recorded daily on a visual analogue scale during the postoperative week. It was shown that preoperative inflammation and the difficulty and duration of the operation increased the intensity of pain.

ISSN:0001-6357    

DOI:10.3109/00016359109041135

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The study aimed to validate the scoring of the degree of marginal degradation of amalgam restorations by using impressions, as an alternative to other indirect scoring methods using photographs or casts. Ten-year-old condensation silicone elastomer impressions and epoxy replicas made in 1979 were compared in a scanning electron microscope at 5 kV with different magnifications up to×200. The impression material was not distorted or degraded, and the dimensional stability was good after 10 years of storage in a dry environment. The inter-examiner agreement of the scorings of impressions and a six-point scale reference set was satisfactory as evaluated by kappa statistics, demonstrating that degrees of marginal degradation can be distinguished on impressions with relatively high accuracy. The rating distribution of the scorings of impressions showed good correlation to the rating distributions obtained with the clinical USPHS rating method and with photographs for recording marginal degradation. A slight difference between the photographic and impression ratings at the upper and lower levels of the six-point rating scale was observed. The difference varied with the type of alloy, possibly due to a bias depending on the surface quality–that is, whether the restoration kept the glossiness of high polishing or became heavily tarnished.

ISSN:0001-6357    

DOI:10.3109/00016359109041136

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Scoring of enamel caries in rat molars in ordinary light and in laser fluorescence was compared. Fifty rats were infected withStreptococcus mutatis; 5 served as control rats, and the other 45 were fed a cariogenic diet for 15–20 days. With Keyes's system, the total enamel caries score for 35 of the test rats was 29.1 lesions per rat (l/r) in ordinary light and 39.6 l/r in laser fluorescence. The corresponding scores for fissure caries were 15.9 l/r and 21.6 l/r, respectively. Fissure caries scores of thin, longitudinal, central sections from the molars of the 10 remaining test rats were 18.0 l/r in ordinary light, 21.4 l/r in laser fluorescence, and 17.1 l/r in microradiographic analysis. In conclusion, the use of laser fluorescence improves scoring of early enamel carious lesions in rat molars, offering potential reductions in test time and/ or sucrose load in animal caries research.

ISSN:0001-6357    

DOI:10.3109/00016359109041137

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The purpose of the present study was to examine failures of fixed prosthodontics during a period of 15 years and to evaluate the quality of those bridges remaining after this period of time. The study group consisted of 102 patients who received 108 bridges made by the senior students at the Dental Faculty, University of Oslo, in 1967/68. All bridges were made of type-3 casting gold and heat-cured acrylic veneering. The mean age of the patients at the beginning of the study was 48 years. Of the original group of 102 patients, 88 attended the clinical examination after 5 years, 71 after 10 years, and 55 after 15 years. Of the 343 abutment teeth 25% were root-filled and restored with post and core. During the 15 years’observation period 26 bridges were lost or had to be remade because of failures. The mean time of service for these bridges were 10.5 years. The failure rate was 4% after 5 years, 12% after 10 years and 32% after 15 years. A modification of the CDA rating system was used for evaluation of the clinical quality of the restorations after 15 years. Between 5% and 14% of the units were recorded as‘not acceptable’for the different characteristics evaluated.

ISSN:0001-6357    

DOI:10.3109/00016359109041138

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Following long-term periodontal treatment with tetracycline a superinfection withCandidamay arise. The reduced environment and the serum transudate of the periodontal pocket may promote such infection. The present in vitro study was performed to ascertain whether yeast-mycelium transformation in a fresh periodontal isolate was promoted under anaerobic conditions and in the presence of serum. C. albicans, isolated from a patient with tetracycline-treated refractory periodontitis, was cultured anaerobically or aerobically on TSBV or Sabou-raud's dextrose agar at 29°C or 37°C for 72 h, with the pH of the medium being 5.6 or 7.2. TSBV medium was also tested with its horse serum or yeast extract removed. Mycelial growth was recorded visually and by stereo and scanning electron microscopy. Anaerobic culture at 29°C or 37°C on TSBV provided abundant mycelium at both pHs. After aerobic culture the mycelial phase was less pronounced and more abundant at pH 7.2 than at 5.6. TSBV without serum or yeast extract yielded more mycelium after anaerobic than after aerobic culture, although less than when both components were included. Sabouraud's medium provided sparse mycelium after anaerobic culture irrespective of the pH, and no mycelium after aerobic culture.

ISSN:0001-6357    

DOI:10.3109/00016359109041139

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The purpose of the study was to estimate the influence of different clinical variables on the replacement rate of class-II amalgam restorations in permanent teeth. The study included 210 patients who had 468 restorations placed by 7 Scandinavian dentists. The observation periods varied between 7 and 10 years. At the time of the last recording 188 restorations remained intact in 88 patients, whereas 68 restorations in 53 patients had been replaced. Eighty-six patients with 212 restorations had dropped out of the study. The most prevalent criteria for replacement were secondary caries (n= 30) and restoration bulk fractures (n= 24). Chi-square analyses of the relationship between the prevalence of replacements and the clinical variables indicated effects of the operator and the patients’age and caries activity (p<0.001). Similar results were observed when the functional time of the restorations was related to the clinical variables and analyzed by ANOVA and MCA analyses and by survival analyses using logrank and Wilcoxon tests (p<0.001). The survival analyses using the Lee-Desu statistic D showed in addition a slight difference between the restorations in the lower premolars and upper and lower molars. There were no differences in the clinical performance between four non-gamma-2 alloys and one conventional alloy. Furthermore, no differences were noted between the survival rates of MO, DO, and MOD restorations. In a Cox regression model the strongest effects on the estimated survival rates were associated with the patients’age and caries activity covariates (global chi-square = 23.5, df = 2,p<0.001), whereas the effects of the operator and the other clinical variables were insignificant.

ISSN:0001-6357    

DOI:10.3109/00016359109041140

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor