Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Cementogenesis”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1975

Accelerated reattachment with cementogenesis to dentin, demineralized in situ. I. Optimum range.

This study confirms an original report describing accelerated reattachment with cementogenesis to root dentin, surgically exposed and demineralized in situ. It additionally describes results of 250 experiments on over 1000 teeth in mongrel dogs and cats designed to identify an optimum range of demineralization related to type of agent, pH, and time of application. This optimum range consistently induces flap reattachment with cementogenesis, while demineralization rates above and below this range enhance reattachment relative to undermineralized controls, but do not consistently induce new cementum. Although most controls demonstrated some reattachment with partial cementogenesis, none produced complete repair as did properly demineralized root surfaces and approximately one-third showed spithelial migration to the apical borders of the wound. No demineralized teeth demonstrated this control result. Small species differences in the response to root demineralization and the degree of hypermineralization of roots adjacent to chronic periodontal pockets, may make optimum ranges determined in this animal study slightly low for human pocket reaattachment techniques.

Animals↗
PubMed1994

Ultrastructure of cementogenesis as affected by growth hormone in the molar periodontium of the hypophysectomized rat.

To document the effect of hypophysectomy and growth hormone replacement on the ultrastructure of cementogenesis in the developing rat third molar, 12 female Wistar rats were randomly allocated to normal control, hypophysectomized or hypophysectomized plus human growth hormone (for 10 days) treatment groups. The results of this study by electron and light microscopy and morphometry have shown that qualitative and quantitative changes occur in the organelles of cementoblasts forming cellular cementum as a result of hypophysectomy and growth hormone replacement. After hypophysectomy, the changes of less prominent nucleoli and nuclear pores, less prominent Golgi apparatuses and decreased endoplasmic reticulum can be interpreted as diminished cementum matrix biosynthesis--an interpretation that can be confirmed morphometrically by less cellular cementum formation. Growth hormone replacement for 10 days reactivates protein synthesis and cementogenesis as evidenced by ultrastructural changes in cementoblasts and a greater production of cementum.

Animals↗
PubMed1982

Experimental induction of cementogenesis on the enamel of transplanted mouse tooth germs.

First and second maxillary molar tooth germs with their surrounding bone were removed from 9-day-old mice, freed of the reduced enamel epithelium, re-inserted crown downwards in their bony crypts and then transplanted in the subcutaneous tissue of hosts of the same age and litter. Grafts were removed 14 days later and prepared for light and electron microscopy. In the areas where the reduced enamel epithelium was missing, a layer of cementum-like tissue was present on the enamel surface, always associated with cells showing the typical features of cementoblasts. A thin electron-lucent layer of fine fibrillar material separated the enamel surface from the new hard tissue which was composed of densely-packed collagen mixed with a ground substance. Where the cementum-like tissue was thick, cells were trapped in a collagenous matrix. The cementogenesis on enamel was strictly dependent on the absence of the reduced enamel epithelium. Thus, when exposed to follicular tissue, the surface of immature enamel appears to exert an influence on follicular cells and stimulate cementogenesis. This hypothesis could explain the presence of overgrowths of cementum in the cervical region of tooth crowns where the reduced enamel epithelium may be particularly vulnerable.

Animals↗
PubMed1976

Accelerated reattachment with cementogenesis to dentin, demineralized in situ. II. Defect repair.

Three surgical experiments, with histologic evaluation, were performed to study induced gingival reattachment to tooth root dentin demineralized in situ during flap surgery in adult mongrel dogs. Experiments demonstrated aspects of: (1) Weekly histochemical and morphological sequences of repair; (2) Repair of chronically inflamed bony defects simulating periodontal pockets; and (3) Six and 12 month repair of reattached surgical defects. Flap reattachment with cementogenesis was induced by in situ root demineralization using citric acid at pH 1.0 applied for 2 minutes. Results demonstrate: (1) The production of anchoring cementum pins extending into dentin tubules widened by demineralization; (2) Reattachment with cementogenesis of inflamed gingiva to roots exposed to chronically-infected surgical defects for 3 months; (3) Success in repairing chronic interproximal one-walled and labial one surface defects by reattachment; (4) Relative failure to repair bifurcation and horizontal bone defects by flap reattachment; and (5) Complete alveolar bone repair over most labial defects by 1 year, with maintenance of a periodontal ligament between induced bone and cementum. These findings, together with previous reports of induced reattachment to demineralized roots, provide further evidence for mechanisms and consistency and suggest that this regenerative phenomenon may be useful in repairing osseous defects in periodontal therapy.

Alveolar Process↗
PubMed1995

Role of two mineral-associated adhesion molecules, osteopontin and bone sialoprotein, during cementogenesis.

Adhesion molecules and their cell membrane receptors are known to play important regulatory roles in cell differentiation. Consequently, the following experiments were conducted to determine the role of two adhesion molecules, bone sialoprotein (BSP) and osteopontin (OPN) in tooth root formation. Developing murine molar tooth germs at sequential stages of development (developmental days 21-42) were analyzed using immunohistochemical and in situ hybridization techniques. While BSP was localized to alveolar bone and odontoblasts early in development, BSP was distinctly localized to the cemental root surface at latter periods coincident with the initiation of root formation and cementogenesis. Conversely, OPN was distributed in a nonspecific fashion throughout the PDL and the eruption pathway of the forming tooth. In situ hybridization confirmed that cells lining the root surface express BSP. The fact that BSP is specifically localized to the cemental surface suggests that this protein is involved in cementoblast differentiation and/or early mineralization of the cementum matrix. Localization of OPN to non-mineralized tissues further suggests that OPN functions as an inhibitor of mineralization during periodontal ligament formation. These findings collectively suggest that BSP and OPN are intimately involved in the sequence of cellular and molecular events accompanying cementogenesis.

Alveolar Process↗
PubMed1994

Bone sialoprotein is localized to the root surface during cementogenesis.

Bone sialoprotein (BSP), an RGD-containing protein with cell attachment properties, is believed to play a regulatory role in the biomineralization of various connective tissues. To determine its possible role in tooth root formation, murine dentoalveolar tissues at sequential phases of development were analyzed immunohistochemically for the presence of BSP. BSP was localized to alveolar bone and cementum at time points associated with initial mineralization of these tissues. In addition, northern blot analyses of dental follicle tissue at day 27 of tooth development indicated that BSP mRNA is expressed by dental follicle cells at a time point coincident with the initiation of cementogenesis on the peripheral tooth root surface. Collectively, these findings indicate that BSP may play an important role in the formation and mineralization of cementum.

Animals↗
PubMed1989

[Effect of various implant materials on cementogenesis].

Various implant materials have been used to stimulate the regeneration of supporting bone lost from periodontal disease. In addition, the histologic features of bone regeneration associated with their implantation have been evaluated. Very little, however, seems to be known about the effect of implant materials on cementum formation. The aim of this study was to determine whether implant materials stimulate the cementogenesis on adjacent planed root surfaces. Twelve monkeys with healthy gingivae were used in this experiment. Following mucoperiosteal flap elevation, "windows" were chiseled in the bone to the proximal root dentin surfaces and adjacent root surfaces were planed. Each of the three implant materials [tricalcium phosphate (TCP), decalcified bone matrix (DBM) and hydroxyapatite (HA)] were then placed in the cuspid and incisor root "windows" before the flap was sutured back into the previous position. Windows with no implantation served as a control. Animals were sacrificed 2, 4 and 8 weeks postoperatively. Biopsy specimens including the tooth and surrounding bone were examined by light and electron microscopy. At 2 weeks, all implant particles were surrounded by fibrous tissue. On the other hand, fibrous tissues filled the control defect. On the planed root surfaces after the implantation of TCP and DBM, furthermore, cementoid tissue appeared. At 4 weeks, a considerable amount of new cementum was deposited on the root surfaces except in the implantation of HA. It was especially pronounced after implantation of TCP and DBM which promoted bone regeneration after resorption. These results suggest that resorbable implant materials such as TCP and DBM not only facilitate the formation of new bone, but also of new cementum.

Animals↗
PubMed1990

Expression of attachment proteins during cementogenesis.

There is general agreement that during development the extracellular environment plays a critical role in controlling cell differentiation. Data generated from numerous studies support the possibility that cell attachment proteins and their corresponding cell receptors are possible candidates for this role. In particular, our studies are directed at identifying attachment proteins in mature cementum and establishing the function of these proteins during root formation. Fractionation of guanidine HCL/EDTA extracts of cementum revealed the presence of a bone-associated attachment, BSP, as well as fractions containing as of yet undetermined attachment proteins. Immunofluorescent examination of 1st molar tissues during root formation, obtained from 7 day-old mice neonates, for bone-associated attachment proteins indicated that osteopontin is expressed in the area of Hertwig's epithelial root sheath, but not in the region of the dental papillae. However, dental papillae cells, considered to have the capacity to form cementum, attached to osteopontin coated dishes, in vitro. Thus, unique attachment proteins, as well as those previously identified, were found in mature cementum and during root development. Future studies focused on identifying attachment proteins of mature cementum and determining the spatial and temporal localization of these proteins, pre- and post-cementogenesis, will provide important information necessary for establishing the function of these proteins during root development.

Animals↗
PubMed1994

Immunolocalization of osteopontin, osteocalcin, and dentin sialoprotein during dental root formation and early cementogenesis in the rat.

Using immunohistochemical methods we studied the tissue localization of the extracellular matrix proteins osteopontin (OPN), osteocalcin (OC), and dentin sialoprotein (DSP) during the formation of acellular and cellular cementum in newly born rats. In the layer of acellular cementum of developing incisor and molar teeth we found a very strong staining for OPN but not for DSP or OC. Many cells immediately adjacent to acellular cementum and PDL cells were also positive for OPN but not for DSP or for OC. In contrast, cellular cementum in molar teeth stained strongly for OPN and OC but not for DSP. Consistent with these observations, the cells engaged in the formation of cellular cementum (cementoblasts and cementocytes) reacted strongly for OPN and OC but not for DSP. In advanced stages of dentinogenesis, both crown and root odontoblasts and dentin stained for OPN, OC, and DSP. Cells and matrices of surrounding alveolar bone stained for OPN and OC but not for DSP. We conclude that cementoblasts and cementocytes of cellular cementum produce OPN and OC but not DSP and thus express an osteoblast-like, not an odontoblast-like, phenotype. The cells responsible for the production of acellular cementum are likely cells of the PDL in close contact with the dental root surface. These fibroblast-like cells express OPN but not OC or DSP and accordingly express only a partial osteoblastic phenotype.

Animals↗