bromochloroacetic-acid and Root-Resorption

Bone sialoprotein (BSP) is an extracellular matrix protein found in mineralized tissues of the skeleton and dentition. BSP is multifunctional, affecting cell attachment and signaling through an RGD integrin-binding region, and acting as a positive regulator for mineral precipitation by nucleating hydroxyapatite crystals. BSP is present in cementum, the hard tissue covering the tooth root that anchors periodontal ligament (PDL) attachment. To test our hypothesis that BSP plays an important role in cementogenesis, we analyzed tooth development in a Bsp null ((-/-)) mouse model. Developmental analysis by histology, histochemistry, and SEM revealed a significant reduction in acellular cementum formation on Bsp (-/-) mouse molar and incisor roots, and the cementum deposited appeared hypomineralized. Structural defects in cementum-PDL interfaces in Bsp (-/-) mice caused PDL detachment, likely contributing to the high incidence of incisor malocclusion. Loss of BSP caused progressively disorganized PDL and significantly increased epithelial down-growth with aging. Bsp (-/-) mice displayed extensive root and alveolar bone resorption, mediated by increased RANKL and the presence of osteoclasts. Results collected here suggest that BSP plays a non-redundant role in acellular cementum formation, likely involved in initiating mineralization on the root surface. Through its importance to cementum integrity, BSP is essential for periodontal function.

Topics: Alkaline Phosphatase; Alveolar Bone Loss; Animals; Cementogenesis; Dental Cementum; Dentin; Epithelium; Incisor; Integrin-Binding Sialoprotein; Keratins; Mice; Mice, Transgenic; Microscopy, Electron, Scanning; Molar; Odontogenesis; Osteoclasts; Osteopontin; Periodontal Attachment Loss; Periodontal Ligament; RANK Ligand; Root Resorption; Tooth Calcification; Tooth Cervix; X-Ray Microtomography

To describe the periodontal membrane of human primary teeth immunohistochemically, while focusing on the epithelial layer of Malassez, fibers, and peripheral nerves, and to compare the findings with those of a previous study of human permanent teeth.. Nineteen human primary teeth extracted in late childhood in connection with treatment were fixed, decalcified, dehydrated, and embedded in paraffin. Paraffin sections were stained with wide spectrum screening (WSS), Vimentin, and NeuN in order to mark the epithelial layer of Malassez, fibers, and peripheral nerves.. For root surfaces without resorption, the epithelial rests of Malassez appeared as small scattered islands. The fibers varied from tightly packed close to the root surface to a messy and loose organization. Innervation could be seen in close proximity to the root surface. The epithelial cells of Malassez were not usually seen along root surfaces with resorption. The fibers were sparse or not present. Innervation was seen in close proximity to the root. In regions with repair of resorption lacunae, the immunohistochemical reactions for epithelial cells of Malassez, fibers, and innervation pattern could be identical to those in regions with no resorption.. In regions without resorption, spatial organization of the periodontal membrane of primary teeth was similar to that of permanent teeth, although the number and distribution of epithelial cells and fibers differed. In regions with repair of root resorption, the epithelial cells of Malassez, fibers, and innervation appeared as root surfaces without resorption.

Topics: Adolescent; Antigens, Nuclear; Child; Connective Tissue; Cuspid; Epithelial Cells; Epithelium; Humans; Immunohistochemistry; Keratins; Molar; Nerve Tissue Proteins; Periodontal Ligament; Root Resorption; Tooth Root; Tooth, Deciduous; Vimentin

There is some evidence that the epithelial cell rests of Malassez partition the root surface from the periodontal ligament blood vessels, and may protect the root from resorption.. The aim of the present study was to determine the distributions of the epithelial rests of Malassez (ERM) and blood vessels in the periodontal ligament (PDL) of the developing rat first molar before, during and after emergence.. Four Sprague-Dawley rats were sacrificed at two days, one week, two weeks, three weeks, four weeks and six weeks of age. After processing, the maxillae were embedded in paraffin, and sectioned longitudinally and transversely. The sections were stained with a double immuno-histochemical technique which utilised a keratin antibody AE1-AE3 (1:2,000) and an endothelial antibody Factor VIII (1:10,000) to enable simultaneous labelling of ERM and blood vessels. ERM and blood vessel counts were obtained from the mesio-buccal roots of three week, four week and six week-old rats, whilst qualitative observations were made for the earlier developmental stages.. ERM cells and cell clusters were found in the tooth third of the PDL width at the three, four and six week stages. Cells and cell clusters increased in number with age, especially in the upper third of the mesio-buccal root. The largest numbers of cells and clusters were found on the distal surfaces of the roots in all age groups. Cells and clusters in all root surfaces increased from three to four weeks, but decreased from four to six weeks. The greatest number of blood vessels was found in the bone-side third of the PDL. The distal surface had the highest proportion of blood vessels, and the palatal surface the least proportion. The number of blood vessels in all surface quadrants did not vary much from three to four weeks of age, but increased from four to six weeks of age, possibly as a reaction to tooth emergence and occlusal function. Physiological root resorption was only observed after tooth emergence, and appeared to be related to loss of continuity of the ERM network and the incursion of blood vessels.. Orthodontic root resorption can be regarded as an exaggerated response to loss of PDL homeostatic control, possibly mediated by the epithelial rests of Malassez.

Topics: Age Factors; Alveolar Process; Animals; Cell Count; Enamel Organ; Epithelial Cells; Factor VII; Keratins; Molar; Odontogenesis; Periodontal Ligament; Rats; Rats, Sprague-Dawley; Root Resorption; Tooth Eruption; Tooth Root

The purpose of the present investigation was to study resorption and regeneration of periodontal tissues incident to orthodontic tooth movement, in particular cells resorbing the root surface and the subsequent regeneration of the periodontal epithelial network and forming reparative cementum. The study was carried out using a select number of immunohistochemical markers on extracted human teeth which had been treated orthodontically. The most striking finding in the resorbing areas was the presence of what appeared to be two populations of KP 1+ mononuclear cells located at a distance of 50-100 microns from the root surface and multinucleated cells in resorption lacunae in close contact with the root surface. KP 1+ has previously not been reported for odontoclasts. The mononuclear KP 1+ cells in the periodontal ligament may represent either precursors to odontoclasts or phagocytic scavenger cells of the macrophage lineage. The subsequent healing of the resorption lacunae was characterized by re-establishment of nervous, vascular and epithelial tissues as evidenced by S-100+ filamentous delicate structures, factor VIII+ vessels and cytokeratin+ clusters of cells, respectively. However, cytokeratin+ single cells in close contact with the unresorbed cementum did not re-appear within the healing period. Although the present results are not quantitative in nature, cementoblasts located in the vicinity of resorption lacunae, especially healing ones, appeared to show an up-regulation of epidermal growth factor (EGF) receptors. It may be suggested the intense positive staining for EGF receptors may be an expression of an auto- or paracrine stimulatory pathway increasing the rate of reparative cementum formation.

Topics: Adolescent; Biomarkers; Cell Lineage; Child; Dental Cementum; Epithelium; ErbB Receptors; Factor VIII; Humans; Immunohistochemistry; Keratins; Leukocytes, Mononuclear; Macrophages; Osteoclasts; Periodontal Ligament; Periodontium; Phagocytosis; Regeneration; Root Resorption; S100 Proteins; Tooth Movement Techniques; Tooth Root; Up-Regulation; Wound Healing

Topics: Ameloblastoma; Diagnosis, Differential; Humans; Keratins; Mandibular Neoplasms; Neoplasm Recurrence, Local; Odontogenic Cysts; Radiography; Root Resorption