摘要:

Age‐related changes in the mechanical strength of the periodontal ligament have been examined by measuring the force required to extract the mandibular first molar from its socket at an extension rate of 5 mm/min in the dissected jaws of growing young rats from 3 to 32 weeks of age. Almost linear increase in the ultimate loads was found from 3 to 8 weeks of age. However the values from 8 to 32 weeks of age did not show any significant differences. Close correlations were found between the ultimate loads and the weights of animals, mandibles and extracted teeth and between the load and length of the tooth from 3 to 8 weeks of age. It is supposed that a mechanical equilibrium has been established within the periodontal ligament in association with various external and internal factors such as root elongation, alveolar bone growth, turnover and maturation of periodontal ligament and occlusal activity, at about 8 weeks of age in the rat mandibular first mola

ISSN:0734-0664    

DOI:10.1111/j.1741-2358.1990.tb00251.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Mechanical properties of the periodontal ligament of the incisor have been examined by pushing the tooth out of its surrounding alveolar bone in sections of the mandibles of rats from 3 to 24 weeks of age. The maximum load, failure energy in shear and elastic stiffness estimated from the load‐deformation curves, showed a tendency to increase with age from 3 to 12 weeks but the maximum deformation did not. Age‐related changes were not appreciable in all mechanical measures estimated from the stress‐strain curves. It is suggested that increases in the maximum load and elastic stiffness from the load‐deformation curves with age are closely related to those in the size of teeth or in the area of the periodontal ligament facing cementum. It is also suggested that qualitative and quantitative changes in the supporting tissues or in the collagen fibres/unit area of the periodontal ligament are minor from 3 to 24 weeks of age in the rat mandibular

ISSN:0734-0664    

DOI:10.1111/j.1741-2358.1990.tb00252.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Mechanical properties of the periodontal ligament of the incisor have been examined in sections of the mandibles of rats from 6 to 24 months of age. Mechanical measures estimated from the load‐deformation and stress‐strain curves did not show age‐related changes, although the body and mandible weights increased gradually during the experimental period. It is suggested that qualitative and quantitative changes in the supporting tissues/unit area of the ligament are minor at a restricted region exa

ISSN:0734-0664    

DOI:10.1111/j.1741-2358.1990.tb00253.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Successful use of an overdentures prosthesis depends on the successful completion and maintenance of endodontically‐treated teeth. The process of completion and maintenance of teeth so treated in elderly individuals is difficult and less predictable. The purpose of this paper is to discuss treatment considerations to enhance success when treating elderly candidates for endodontic overdenture abutment retentio

ISSN:0734-0664    

DOI:10.1111/j.1741-2358.1990.tb00254.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

ISSN:0734-0664    

DOI:10.1111/j.1741-2358.1990.tb00255.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Ninety‐two head and neck radiation/oncology patients were referred for a pre‐irradiation dental examination. Of these patients, 48 required at least one extraction, and 51 required at least one restoration. Only 19 patients did not require extractions, restorations or endodontic therapy. All but one patient required a dental prophylaxis. The oral complications of head and neck irradiation therapy were evaluated and discussed. The importance of adjuvant oral/dental care for the head and neck radiation/oncology patient is addressed. The distribution of patients requiring treatment (extractions, restorations and/or endodontic therapy) versus no treatment (a dental prophylaxis only) showed that a significantly higher number of patients (chi‐square [1] = 37.5;p<0.01) required treatment over no trea

ISSN:0734-0664    

DOI:10.1111/j.1741-2358.1990.tb00256.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

The intertwined effects of normal aging processes and time‐progressive diseases produce systematic changes in many oral and dental tissues. This cross‐sectional study of pulp dimensions and root lengths in sound teeth tested for changes with age in adulthood while controlling for differences in gender and race (black, white). Age was the paramount determinant of pulp size which decreases via the accumulation of secondary dentin. In some instances the rate of change increases in older adults with an inflection point at 35–40 years of age. In contrast, root lengths are statistically independent of age once gender (male>female) and race (black>white) are controlled. Causes of the lack of association with age are disc

ISSN:0734-0664    

DOI:10.1111/j.1741-2358.1990.tb00257.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Normal gingival tissues of BNL mice of different ages were studied, using recently developed immunohistochemical techniques to detect T and B lymphocytes, Langerhans cells and macrophages. The presence of mast cells, plasma cells and neutrophils was also determined. Cell densities were determined in the epithelium and connective tissue compartments of the attachment area, the papilla and the diastema. T lymphocytes (Lyt 1*) were present in the epithelium and connective tissue of all three areas studied. Their numbers increased significantly with age in the attachment area and in the papillary connective tissue. Langerhans cells (F4/80*) were detected in the epithelium of all three areas examined. Their numbers did not vary significantly with age. The highest concentrations of T lymphocytes and Langerhans cells were observed in the attachment area at all ages. Macrophages (F4/80*) were detected in the connective tissue of all three areas examined. Their numbers increased significantly in the papillary connective tissue of older animals (78 weeks of age). Neither B lymphocytes (RA‐2C2′) nor plasma cells were detected in any of the tissue areas examined. The presence of neutrophils in the attachment area increased with age. Mast cells were present in all samples in the more vascularized areas (the papilla and diastema). The results suggest that, throughout the lifespan, T lymphocytes, macrophages, Langerhans cells and mast cells are normal constituents of the oral mucosa of the mouse, while B lymphocytes, plasma cells and, for the most part, neutrophils are absent under normal conditions. Furthermore, the concentrations of T lymphocytes and macrophages increased with age in the areas adjacent to the dentition, possibly as a result of reduced tissue resistance to external antig

ISSN:0734-0664    

DOI:10.1111/j.1741-2358.1990.tb00258.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

A clinical survey of oral soft tissue lesions in 298 geriatric patients in Israel was conducted. White lesions were found in 9.5% of smokers and 2.19% of non‐smokers. Varicosities increased from 11.1 % to 41.1% between ages 50–99 years. Pigmentation hairy tongue, and papillary atrophy of the tongue all increased with age. Hairy tongue was found in 12.8% of men and 4 5% of wo

ISSN:0734-0664    

DOI:10.1111/j.1741-2358.1990.tb00259.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

ISSN:0734-0664    

DOI:10.1111/j.1741-2358.1990.tb00260.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY