Comparison of expression patterns of cathepsin K and MMP-9 in odontoclasts and osteoclasts in physiological root resorption in the rat molar.
(74/177)
Root resorption lacunae are principally formed by odontoclasts. While these cells develop from the same origin as osteoclasts, odontoclasts normally have fewer nuclei and a less clear zone compared with osteoclasts. We therefore, hypothesized that odontoclasts possess less differentiation in matrix resorption characteristics than osteoclasts. To test our hypothesis, we compared the TRAP-positive area and the expression patterns of two important proteolytic enzymes, cathepsin K and matrix metalloproteinase-9 (MMP-9), between odontoclasts and osteoclasts. We focused on physiological root resorption in the rat molar, which is a useful experimental model for estimating odontoclasts and osteoclasts. Observations showed the number of nuclei and the TRAP-positive area of odontoclasts to be significantly less compared with osteoclasts. Using in situ hybridization and double labeling fluorescence in situ hybridization showed the majority of odontoclasts to express both cathepsin K and MMP-9, especially 4 and 5 weeks of age, when physiological root resorption occurs actively. Moreover, putative precursor cells of odontoclasts, which typically appeared in the middle of the periodontal ligament at 3 weeks of age, expressed both enzymes. In contrast, the majority of matured osteoclasts expressed only cathepsin K but not MMP-9. We suggest that odontoclasts are comparable to osteoclasts with less differentiation with regard to the expression of proteolytic enzymes. (+info)
Immunology of root resorption: a literature review.
(75/177)
Root resorption seems to be related to a complex combination of mechanical factors and biological activity, which comprehends the role of immunologic structures including specialized cells. The aim of this research was to explain the development of the process--from mineralization to the destruction of hard tissues--and the possible relationship between root resorption and immunology, along with discussing current concepts described in the literature. (+info)
A scanning electron microscopic study of hypercementosis.
(76/177)
Root resorption and the OPG/RANKL/RANK system: a mini review.
(77/177)
Odontoclastic root resorption is a significant clinical issue in relation to orthodontic tooth movement, and resorption of the roots of primary teeth is an intriguing biological phenomenon. The functional coordination of the OPG/RANKL/RANK system seems to contribute not only to alveolar remodeling, but also to resorption during orthodontic tooth movement and physiological root resorption. Serum OPG and s-RANKL are related to regulation of bone homeostasis by the OPG/RANKL/RANK system, and determination of their concentrations might be useful for predicting the rate of bone remodeling during orthodontic tooth movement, the net effect between bone remodeling and root resorption, and the degree of root resorption. It is therefore rational to speculate that a study of the levels of OPG and s-RANKL in blood and GCF, in relation to the degree of root resorption during orthodontic tooth movement, using healthy experimental animals and a carefully planned and organized experimental design, may be able to answer this intriguing question. (+info)
Cervical external root resorption: 3-year follow-up of a case.
(78/177)
Cervical external root resorption can be present in natural teeth, involving one or more teeth in the same patient. The incidence of these lesions appears random and the etiology remains unclear. Cervical external root resorption has been considered a difficult clinical situation, and its diagnosis and treatment of the defect challenging. The present report describes a case of multiple external cervical resorption lesions involving four teeth, including the history, and the clinical and radiographic findings. The treatment included surgical intervention and restoration of the defect without sacrificing the pulp. A 3-year re-evaluation of the case confirmed a stable, uneventful clinical recovery. (+info)
Histological changes in human dental pulp following application of intrusive and extrusive orthodontic forces.
(79/177)
The aim of this study was to compare the effects of orthodontic extrusive and intrusive forces on histological changes of the human dental pulp. In this clinical trial, 52 sound upper first premolars from 26 patients scheduled for extraction for orthodontic reasons were selected. They were divided into 2 groups, based on the time intervals for histological evaluation (3 days and 3 weeks). In each group, 10 teeth received orthodontic extrusive forces, 10 teeth underwent intrusive forces, and 6 teeth served as controls. After each period, teeth were extracted and prepared for histological examination under light microscopy and some histological parameters were evaluated. The data were statistically analyzed by Kruskall-Wallis and Mann Whitney tests. Of the parameters evaluated, just vacuolization and disruption of the odontoblastic layer showed statistically significant differences between the control group and both of the experimental groups in each test period (P < 0.05). Additionally, there was no significant difference between 3-day and 3-week intervals in each experimental group, except for fibrosis in the extrusive group which significantly increased after 3 weeks of force application (P = 0.001). Histological pulp changes following extrusive and intrusive force applications for 3 days and 3 weeks show no difference from each other. (+info)
Adenomatoid odontogenic tumor - hamartoma or true neoplasm: a case report.
(80/177)
Adenomatoid odontogenic tumor (AOT) is an uncommon tumor of odontogenic origin with a relative frequency of 2.2 - 7.1%. As the histogenesis of AOT is still uncertain, it is sometimes categorized as a hamartomatous lesion rather than a true neoplasm. We report a case of AOT in the right maxillary anterior region in a 20-year-old woman. The tumor showed some unusual and aggressive features that suggested it was a true neoplasm. (+info)