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At least 613 records · Page 34Linked to original sources
PubMed2006

Preserving pulpal health of a geminated maxillary lateral incisor through multidisciplinary care.

AIM: To report the multidisciplinary care of an unaesthetic geminated maxillary lateral incisor tooth, which allowed its preservation in the mouth. SUMMARY: Preoperative examination of an unsightly geminated maxillary lateral incisor (tooth 22) demonstrated two pulp chambers and open apices, with normal pulp sensitivity responses. At surgery, a periodontal mucoperiosteal flap was reflected and the distal part of the geminated tooth was removed. The exposed root canal of the preserved tooth was sealed with mineral trioxide aggregate (MTA). The extraction socket and osseous defect was grafted with decalcified freeze-dried bone allograft (DFDBA) before flap closure. During follow-up, distal caries in tooth 22 and a diastema between tooth 22 and 23 were managed with composite resin restorations. Forty-two months postoperatively, normal thermal and electrical pulp sensitivity tests confirmed pulp health. Convincing apexogenesis and dentinogenesis of the developing root was confirmed by radiographic examination. Acceptable periodontal health including 3-4 mm clinical probing depths was achieved. Optimizing aesthetics and occlusion was accomplished without orthodontic treatment.

Aluminum Compounds↗
PubMed1999

Discrimination of morphological findings in dentine from osteogenesis imperfecta patients using combinations of polarized light microscopy, microradiography and scanning electron microscopy.

OBJECTIVES: The aim of this study was to investigate the morphological appearance of dentine in teeth from individuals with osteogenesis imperfecta type I, III and IV using different histological techniques, and to correlate morphological findings to different types of osteogenesis imperfecta. SAMPLE AND METHODS: Extracted or exfoliated primary and permanent teeth were collected from 15 patients with the osteogenesis imperfecta diagnoses I, III or IV, with or without the additional diagnosis dentinogenesis imperfecta. Ground and decalcified sections were prepared from the teeth. Histo-morphological studies of the dentine were performed utilizing light and polarized light microscopy, microradiography and scanning electron microscopy. RESULTS: Characteristic findings were irregular tubules, remnants of capillary inclusions and obliterated pulps. All types of osteogenesis imperfecta exhibited similar types of dentine aberrations, but patients with type III or IV had a higher frequency of aberrations when compared to type I. CONCLUSIONS: The combination of either polarized light microscopy or micro-radiography, together with scanning electron microscopy, gave the most amount of morphological information from dentine samples. In addition, aberrations in dentine structure were more clearly observable. Light microscopy was not critical for the analyses.

Adolescent↗
PubMed1988

Developmental expression of 44-kDa bone phosphoprotein (osteopontin) and bone gamma-carboxyglutamic acid (Gla)-containing protein (osteocalcin) in calcifying tissues of rat.

New aspects of the distribution and developmental appearance of the 44-kDa bone phosphoprotein (44K BPP, also called sialoprotein I or osteopontin) and bone gamma-carboxyglutamic acid (Gla)-containing protein (BGP, also called osteocalcin) during osteogenesis and dentinogenesis were investigated with immunocytochemical techniques using monospecific, affinity-purified polyclonal antibodies. Sections from newborn rat incisors and from various bone anlagen of newborn animals and fetuses were processed for detection of 44K BPP or BGP antigenicity. In addition, histochemical reactions for detection of alkaline phosphatase or calcium salts were performed on a number of the sections. The 44K BPP appears to be synthesized and secreted by chondrocytes only in the areas of cartilage-to-bone transition; these cells could participate indirectly in the process of bone formation by providing a suitable scaffold onto which primary marrow osteoblasts attach and spread. During osteogenesis, 44K BPP is found in bone-forming cells almost concomitantly with the appearance of alkaline phosphatase and before osteoid deposition, whereas BGP is still absent during early stages of mineralization. We hypothesize that this dramatic difference between the developmental appearance of 44K BPP and BGP reflects the delayed expression of the BGP gene relative to that of 44K BPP. In long-term cultures of bone marrow from adult mice, some fibroblastic cells expressed the 44K BPP phenotype; these cells could represent early osteogenic progenitor cells. Some experiments also suggested that, as with BGP, 44K BPP or an immunologically related protein is synthesized by some odontoblasts and secreted into predentin, prior to the onset of mineralization.

Alkaline Phosphatase↗
PubMed1994

Osteogenesis imperfecta in Holstein-Friesian calves.

Eight calves with osteogenesis imperfecta were born in a Danish Holstein-Friesian herd during a two-year period. In total 92 calves were born (84 normal), and all were sired by a clinically normal Holstein-Friesian bull. The defect was probably due to a de novo dominant mutation present as a gonadal mosaicism in the bull. Affected calves were characterised by multiple fractures, congenital bone deformations, general joint laxity, dentinogenesis imperfecta, and light blue sclerae. The skin seemed normal. Electron microscopical studies revealed slightly decreased average diameter of cutaneous collagen fibrils, while the diameter of collagen fibrils in tendons and ligaments was severely reduced. Abnormalities of collagen type I from skin and compact bone were not detected by biochemical analyses.

Animals↗
PubMed2004

Immunocytochemistry of keratan sulfate proteoglycan and dermatan sulfate proteoglycan in porcine tooth-germ dentin.

Keratan sulfate proteoglycan and dermatan sulfate proteoglycan have been reported to inhibit collagen fibrillogenesis. We investigated their distribution in order to evaluate the role of proteoglycan in dentinogenesis. Specimens of porcine tooth-germ dentin and erupted teeth were the materials on which antibodies to keratin sulfate and dermatan sulfate proteoglycan were used. Predentin was found to be positive for both antibodies and the reaction ceased in the calcification front. Uniformly thick collagen fibrils (30-70 nm in diameter) were distributed in the predentin matrix, which would become intertubular dentin in the future. Both antibodies reacted positively along these fibrils. In contrast, along the surface layer of dentin in the tooth germ and that in erupted teeth, collagen fibrils of 10-300 nm in diameter were noted occasionally in dentinal tubules whose odontoblastic processes had disappeared and these heterogeneous fibrils were negative for both antibodies. Our findings suggest that keratan sulfate proteoglycan and dermatan sulfate proteoglycan distributed in the predentin inhibit calcification of collagen fibrils in the uncalcified matrix and disappear in the calcification front. It is further suggested that keratan sulfate proteoglycan and dermatan sulfate proteoglycan distributed along collagen fibrils in the predentin matrix maintain uniform thickness, whereas collagen fibrils in dentinal tubules varied in thickness because of the absence of involvement of both proteoglycans. Therefore, keratan sulfate proteoglycan and dermatan sulfate proteoglycan were thought to be involved in both calcification and matrix formation.

Animals↗
PubMed1975

Congenital oral anomalies in argentinian children.

A total of 6,180 Argentinian school-age children were examined clinically for the presence of oral congenital anomalies. The following prevalence figures were found: commissured lip pits (0.7%), ankyloglossia (0.1%), geographic tongue (1.5%), localized enamel hypomaturation (2.8%), median rhomboid glossitis (0.10/00), torus palatinus (0.30/00) and dentinogenesis imperfecta (0.30/00). Data are presented for the first time on snowcap amelogenesis imperfecta with a prevalence value of 0.1%.

Adolescent↗
PubMed1984

Effects of vitamin A deficiency on rat incisor formation.

Vitamin A deficiency (A-) is known to cause morphologic changes in tooth structures. However, its effects on glycosaminoglycan (GAG) distribution in dental pulp, and the role of retinoic acid (RA) in altering these effects are not clearly defined. Tissue changes induced by vitamin A deficiency and RA administration were evaluated histologically in incisors of rats fed on one of 3 different diets: a) vitamin A sufficient (A+); b) vitamin A deficient (A-); and c) vitamin A deficient supplemented with retinoic acid (A-/RA). Four weeks after the onset of vitamin A deficiency, all rats were killed and their 4 continuously erupting incisors evaluated histologically. A- rats had altered dentine and pulp with disrupted histodifferentiation of pulpal mesenchymal cells to normal odontoblasts. The frequency of these abnormalities in dentine and pulp was lower in A-/RA rats. The enamel organ was unremarkable in the 4-week deficient period. Using special stains, we noted that pulpal GAG accumulation in A- and A-/RA rats was limited to the lingual area, while in A+ rats, GAG were distributed throughout. These data suggest that vitamin A deficiency affects histodifferentiation of pulpal mesenchymal cells to odontoblasts, as well as GAG distribution in pulp. RA administration reduces the A- changes and therefore, appears to have some activity in dentinogenesis.

Animals↗
PubMed1992

Ehlers Danlos syndrome type I with novel dental features.

The clinical, radiographic and histologic findings are described in two cases of Ehlers Danlos Syndrome Type I with novel dental features. Defective dentinogenesis principally affecting the mandibular incisors result in aplasia or hypoplasia of root development predisposing to localized periodontal disease. A striking radiographic appearance with a bulbous enlargement of the roots together with pulp stones is seen in other teeth. 'Giant channels' and vascular inclusions resembling 'intermediate cementum' are prominent within this area. No evidence of Type III procollagen or collagen was detected with indirect immunofluorescence. It is suggested that an inherited collagen abnormality in a component common to dentin, skin, ligament and tendon probably explains both EDS I and the dentin dysplasia.

Adult↗
PubMed1988

Transmission electron microscopic study of giant tubules in bovine dentin.

Giant tubules in the axiomesiodistally extended incisal dentin of unerupted permanent bovine incisors from 1/2-1 1/2-yr-old calves were studied by TEM. The pulpal portion of each giant tubule contained two capillaries forming a loop incisally. The capillaries consisted of a delicate, continuous, or fenestrated endothelium and often had a pericyte coating. Cells with a rich RER, mitochondria, and Golgi apparatus dominated along and just incisal to the vessels. Extravasated erythrocytes and occasional macrophages were also seen in the latter location. It was suggested that the pulpal retraction of the giant tubule vessels during primary dentinogenesis might be the result of an intermittent sequestration of the most incisal portion of the loop, concomitant with endothelial proliferation in the pulpal portion of the capillaries. The major portion of the giant tubules, incisal to the vessels, contained a dense matrix of more or less axially oriented unmineralized 0.07-0.1-micron-thick collagen fibrils and single cells showing gradually increasing degenerative and necrotic changes in an incisal direction. Longitudinal sections of the mineralized tubular walls revealed transversely cut collagen fibrils. The incisally located giant tubule origins were circumvented by dentinal tubules and contained 0.10-0.22-micron-thick, densely packed collagen fibrils with an electron dense perifibrillar zone.

Animals↗
PubMed1998

Calcium- and hydroxyapatite-binding properties of glucuronic acid-rich and iduronic acid-rich glycosaminoglycans and proteoglycans.

This study describes the interaction of a small chondroitin sulphate proteoglycan and the glycosaminoglycans chondroitin 4-sulphate, dermatan sulphate and heparan sulphate with hydroxyapatite. All macromolecules possessed a high affinity, with the iduronic acid-rich dermatan sulphate and heparan sulphate displaying higher adsorption maxima than the glucuronic acid-rich chondroitin 4-sulphate. At similar concentrations, dermatan sulphate produced a 30% inhibition of hydroxyapatite-induced crystal growth, whilst chondroitin 4-sulphate yielded 50% inhibition. Estimation of the calcium binding capacity of these glycosaminoglycans using equilibrium dialysis indicated that chondroitin 4-sulphate bound five times more calcium than dermatan sulphate at a calcium concentration similar to that of serum. The data indicate a possible important role for chondroitin 4-sulphate in dentinogenesis where it is the dominant glycosaminoglycan, since it could act as a capture point for calcium ions during mineralisation, with the leucine-rich domain of its parent proteoglycan acting as anchor points to type I collagen.

Adsorption↗
PubMed2006

Adsorption and interactions of dentine phosphoprotein with hydroxyapatite and collagen.

Dentine phosphoprotein (DPP) has been proposed to both promote and inhibit mineral deposition during dentinogenesis. The present study aimed to investigate the molecular interactions of DPP and dephosphorylated DPP (DPP-p) with hydroxyapatite (HAP). Bovine DPP was purified and dephosphorylated by alkaline phosphatase to obtain DPP-p. DPP and DPP-p adsorption to HAP was determined along with their ability, when free in solution or bound to collagen, to influence HAP-induced crystal growth. Absorption isotherms suggested that lower DPP concentrations (1.5-6.25 microg ml(-1)) demonstrated a reduced affinity for HAP compared with higher protein concentrations (12.5-50.0 microg ml(-1)). Dephosphorylated DPP had a much reduced affinity for HAP compared with DPP. Dentine phosphoprotein inhibited seeded HAP crystal growth, in a dose-dependent manner, whilst removal of the phosphate groups reduced this inhibition. When bound to collagen fibrils, DPP significantly promoted the rate of HAP crystal growth over 0-8 min. Conversely, DPP-p and collagen significantly decreased the rate of crystal growth over 0-18 min. These results indicate a major role for the phosphate groups present on DPP in HAP crystal growth. In addition, concentration-dependent conformational changes to DPP, and the interaction with other matrix components, such as collagen, are important in predicting its dual role in the mineralization of dentine.

Absorption↗
PubMed1992

Primate dentine extracellular matrix induces bone differentiation in heterotopic sites of the baboon (Papio ursinus).

In rodents, demineralized dentine matrix induces local differentiation of endochondral bone. This study investigated the osteoinductive potential of primate dentine matrices when implanted extraskeletally in allogeneic recipients. Demineralized dentine cylinders prepared from adult baboon incisors and demineralized dentine matrix pulverized to a particle size of 74-420 microns were implanted into the rectus abdominis of 4 subadult male baboons (Papio ursinus). Specimens were harvested 30 and 90 d after implantation. Histological analysis on serial sections showed bone differentiation in demineralized dentine cylinders after partial resorption of the external demineralized layer, and in resorption lacunae and excavation chambers within the matrix. Implants of demineralized dentine matrix of 74-420 microns particle size showed no osteoinductive activity as determined biochemically (alkaline phosphatase activity) and histologically. The demonstration of bone induction by primate dentine prepared from fully erupted tooth matrix suggests that putative osteogenic proteins may be conserved after dentinogenesis and embryonic tooth development, and may play a role during healing after surface demineralization of exposed root surfaces during regenerative procedures in humans.

Animals↗
PubMed1995

Localization and expression of osteopontin in mineralized and nonmineralized tissues of the periodontium.

To summarize results from various studies focusing on determining the expression/localization of BSP and OPN during tooth root development, there is general agreement that OPN is expressed/localized to the root surface during cementogenesis and is also seen throughout the PDL region. The expression/localization of OPN to odontoblasts and its role in dentinogenesis is less apparent. Recent studies directed at establishing odontoblast cell lines should help to resolve this conflict. Studies on BSP expression during tooth root formation indicate a very precise expression and localization of this molecule during cementogenesis indicating that this molecule may play an important role in the formation of this mineralized tissue. However, as with OPN, the expression of BSP and its role in dentin formation is not clearly defined.

Animals↗
PubMed2003

Diagnosis and management of unusual dental abscesses in children.

Although the majority of dental abscesses in children originate from dental caries or trauma, a few are associated with unusual conditions which challenge diagnosis and management. Recent research findings have shed light on these unusual entities and greatly improved understanding of their clinical implications. These conditions include developmental abnormalities such as dens invaginatus in which there is an invagination of dental tissues into the pulp chamber and dens evaginatus in which a tubercle containing pulp is found on the external surface of a tooth crown. In addition, inherited conditions which show abnormal dentine such as dentine dysplasia, dentinogenesis imperfecta, and osteogenesis imperfecta predispose the dentition to abscess formation. Furthermore, 'spontaneous' dental abscesses are frequently encountered in familial hypophosphataemia, also known as vitamin D-resistant rickets, in which there is hypomineralization of dentine and enlargement of the pulp. In addition to developmental conditions, there are also acquired conditions which may cause unusual dental abscesses. These include pre-eruptive intracoronal resorption which was previously known as 'pre-eruptive caries' or the 'fluoride bomb'. In addition, some undiagnosed infections associated with developing teeth are now thought to be the mandibular infected buccal cysts which originate from infection of the developing dental follicles. In the present paper, these relatively unknown entities which cause unusual abscesses in children are reviewed with the aim of updating the general practitioner in their diagnosis and management.

Abscess↗
PubMed1989

Clinical variability of osteogenesis imperfecta linked to COL1A2 and associated with a structural defect in the type I collagen molecule.

We report a family in which dominant osteogenesis imperfecta segregates with a COL1A2 haplotype and is associated with a structural defect in the helical region of the type I procollagen molecule. All affected subjects had short stature, dentinogenesis imperfecta, and myopia; however, great differences were observed in the number of fractures and in the degree of bone deformity. Identical biochemical changes were found in the type I collagen molecules synthesised by fibroblasts of subjects with severe or minimal bone fragility. These results confirm that mutations in the triple helical region of alpha 2(I) chains produce a milder phenotype than analogous mutations in the alpha 1(I) chains, but indicate that, in addition to defects in the type I collagen molecule, other factors may modulate the degree of bone involvement in osteogenesis imperfecta.

Adult↗
PubMed2000

Distribution of interglobular dentine in human tooth roots.

The present study was designed to examine the distribution of interglobular dentine in human tooth roots. The material comprised 17 teeth, of which 3 were premolars extracted for orthodontic reasons from children 10-12 years of age and the other teeth (4 incisors, 3 canines and 7 molars) were extracted for periodontitis from individuals aged 32-63 years. All teeth were free of caries and cervical dentine defects. Ground sections of the teeth cut longitudinally were stained with basic fuchsin and observed by fluorescence and confocal microscopy as well as transmitted light microscopy. Basic fuchsin stained the dentinal tubules, interglobular dentine and the granular layer of Tomes. These structures appeared intense blue to faint violet with transmitted light microscopy, whereas their staining displayed intense fluorescence with fluorescence microscopy. Therefore, the interglobular dentine could be detected more sensitively with fluorescence and confocal microscopy than with transmitted light microscopy. Typical interglobular dentine was present in coronal dentine in most of the teeth. In the radicular dentin, position and size of the interglobular dentine was different among the teeth examined. Most of the teeth had the interglobular dentine in the cervical part of the roots (type A). Two premolars displayed the interglobular dentine in the coronal half of the root (type B). The types A and B contained large interglobular areas. A small amount of interglobular dentine was restricted to the apical half of the roots of two canines and one molar (type C). In contrast to types A and B which were seen at both labial or buccal and lingual sides of roots, the interglobular dentine of type C was seen only at one side, labial or lingual. Some of the tooth roots did not show any interglobular dentine (type D). Most of the incisors, canines and premolar were types A, B, and C, respectively, and the molars were mixed types A, C, and D. These results suggest that the factors affecting dentinogenesis during root formation are unique for each tooth.

Adult↗
PubMed1983

Crystal growth in matrix vesicles of permanent tooth germs in kittens.

Dentinogenesis of permanent tooth germs in kittens was examined in a transmission electron microscope. Crystals of various sizes (3-30 A in width) appeared in the matrix vesicles. Electron diffractional features revealed that crystal size in electron micrographs reflected various stages of crystal growth. Pairs of small crystals and dislocated crystals were observed in some crystal-containing matrix vesicles. However, these matrix vesicles were not observed in unmineralized matrix just adjacent to calcifying fronts and in mineralized dentin. Furthermore, long crystals were abundant in mature dentin. These findings suggest that crystal growth in matrix vesicles is due to fusion and that dentin maturation progresses through crystal growth along the long axis.

Animals↗
PubMed1987

Immunocytochemical localization of osteocalcin in developing rat teeth.

Osteocalcin was purified by gel chromatography from a crude extract obtained after decalcification of rat incisors. The apparent molecular weight, as determined by 5-15% SDS-polyacrylamide gel electrophoresis, was 18,000, and amino acid analysis revealed 60 gamma-carboxyglutamic acid residues per 1000. Antisera against osteocalcin, raised in rabbits, reacted specifically with osteocalcin when investigated by immuno-electroblotting of dentin crude extract. 4-micron cryosections of formaldehyde-fixed tooth germs showed positive immunocytochemical staining for osteocalcin in dentin and odontoblasts. The staining of the mantle dentin at the coronal sides of the tooth germs was more intense than that of the adjacent circumpulpal dentin, while the odontoblasts involved in the formation of mantle dentin showed stronger immunoreactivity than did odontoblasts involved in circumpulpal dentin formation. This marked difference was not observed on the root sides of the tooth germs. In 1-micron cryosections, osteocalcin immunoreactivity was found evenly distributed throughout the entire cell body, with the exception of the Golgi region, which was less intensely stained, while the nucleus and the cell process were negative. The positive staining reaction with anti-osteocalcin antiserum was found in dentin from the very onset of its formation in the fetus. In conclusion, our results demonstrate the presence of osteocalcin in odontoblasts and dentin. Its immunocytochemical localization may be compatible with a distinct role in early dentinogenesis.

Animals↗