Xinping Fan | PubMed Health

PubMed2003

[A comparative study utilizing different methods for establishing an experimental periodontitis model in rats].

OBJECTIVE: To evaluate the experimental periodontitis in rats induced by ligature plus high sugar water with and without infection of periodontopathic bacteria. METHODS: Forty SD rats (5 weeks of age) were randomly divided into a control group (N) and three experimental groups (P1, P2 and P3). All experimental groups were given silk ligatures around the cervix of the second maxillary molars and were provided with drinking water containing 10% glucose. Group P2 was inoculated with P. gingivalis, three times; group P3 was inoculated with P. gingivalis and F. nucleatum, three times. At weeks 0, 2 and 4, microbiological and histological examinations were made; alveolar bone loss was stereoscopically measured as the distance from the cement-enamel junction to the alveolar crest. RESULTS: Microbiological examination indicated that the bacteria inoculated in groups P2 and P3 were successfully colonized and both of P. gingivalis and F. nucleatum were predominant among the bacterial colonies of the examined sites. At week 2, histological examination showed gingival erosion and alveolar bone loss in all experimental groups and periodontal pockets in groups P2 and P3. The most serious lesions were observed in group P3. At week 4, the periodontal destruction in all experimental groups became more severe. CONCLUSION: Ligature, high sugar water combined with mixed infection of periodontopathic bacteria can successfully induce experimental periodontitis in rats.

Animals↗

PubMed2002

[Comparison of machinability of two types of dental machinable ceramic].

OBJECTIVE: In terms of the problems of now available dental machinable ceramics, a new type of calcium-mica glass-ceramic, PMC-I ceramic, was developed, and its machinability was compared with that of Vita MKII quantitatively. Moreover, the relationship between the strength and the machinability of PMC-I ceramic was studied. METHODS: Samples of PMC-I ceramic were divided into four groups according to their nucleation procedures. 600-seconds drilling tests were conducted with high-speed steel tools (Phi = 2.3 mm) to measure the drilling depths of Vita MKII ceramic and PMC-I ceramic, while constant drilling speed of 600 rpm and constant axial load of 39.2 N were used. And the 3-point bending strength of the four groups of PMC-I ceramic were recorded. RESULTS: Drilling depth of Vita MKII was 0.71 mm, while the depths of the four groups of PMC-I ceramic were 0.88 mm, 1.40 mm, 0.40 mm and 0.90 mm, respectively. Group B of PMC-I ceramic showed the largest depth of 1.40 mm and was statistically different from other groups and Vita MKII. And the strength of the four groups of PMC-I ceramic were 137.7, 210.2, 118.0 and 106.0 MPa, respectively. CONCLUSION: The machinability of the new developed dental machinable ceramic of PMC-I could meet the need of the clinic.

Dental Porcelain↗