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The Author presents a case of permanence of two canine deciduous teeth in the upper jaw of a grown-up person for the absence of a side incisor and three premolars. Furthermore he presents personal histological findings of the pulp of two teeth and the biological meanings are discussed.
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The technique of dynamic secondary ion mass spectrometry (SIMS) has, during the 1980s, become a firmly established tool in the microanalytical and microstructural characterization of dental hard tissues. SIMS has proved to be outstandingly suited for charting the distributions of most elements, even at extremely low concentrations, in tooth and bone materials. In-depth concentration profiles as well as surface distribution maps of elements have been recorded with excellent (sub-micron) morphologic resolution. In spite of documented success, only relatively few teams, in a handful of countries, are presently engaged, to any significant extent, in conducting tooth or bone research by the application of SIMS. For dental-medical-surgical laboratories, a partial reason for non-communication is a lack of information about SIMS and its particular assets. Another reason may be connected with an essentially groundless reputation, among non-specialists, of SIMS being an exclusive and expensive technique. Among SIMS laboratories, on the other hand, the inertia in tackling biomineralization is partly due to some particular artifacts of analysis, hitherto not generally known and controlled. The present paper briefly sketches the chief principles of modern SIMS, emphasizing factors of special relevance in the characterization of biomineralized tissues. Examples of recent applications are provided. Present procedures and their limitations are discussed, especially with regard to elemental quantification and imaging. Suggestions for relatively simple modifications to existing routines are offered with the aim of enhancing the ease and availability of SIMS in odontological and surgical research.
Variations of mineral and protein metabolism in calcified tissues were studied using 32P, 45Ca and 35S methionine in the rats on sugar diet and water of different hardness with F and without it. Hard drinking water without F like soft water and water of medium hardness with F affect metabolism in mineralized tissues preventing the development of carious process. Incorporation of 32P and 45Ca to mineralized tissues, specific radioactivity of 32P and 35S methionine of tooth and bone proteins are lower in rats which drank soft water without F. These parameters increase in rats which received hard water without F almost to the level of animals which received water with F. Ways of the effect of Ca2+ Mg2+ and F on protein and mineral metabolism of calcified tissues of rats on sugar diet (including proteins (osteo-induced, etc., which initiate mineralization) and enzymes are considered.
The purpose of this study was to determine the difference, if any, in the thermal stability of collagen in mineralized and demineralized dentine compared to that in unmineralized tissues, using differential scanning calorimetry, DSC. Human tooth dentin blocks, about 1 x 1 x 2 mm in size, were used in this study. Some dentin blocks were demineralized using a Plank Rychlo solution; others, using EDTA solution. The mineralized dentin showed an exothermic peak at about 310 degrees C and the combustion of organic materials was completed at about 450 degrees C. For the demineralized dentin, the combustion was completed at higher temperature range and showed a strong exothermic peak at about 470 degrees C. An exotherm at the temperature between 450 degrees C and 470 degrees C was also observed in DSC pattern of native type I collagen from calf skin and rat tail tendon. DSC pattern of rat tail collagen showed a close similarity to that of the demineralized dentin. Statistically, the same heat flow value was obtained both from the mineralized dentin and the demineralized dentin and from the native type I collagen. These findings indicated that the thermal stability of collagen in dentin is lower than collagen in uncalcified connective tissue. It is suggested that in calcified collagen, the apatite crystallites may have intruded into spaces of the crosslinks of intra- and inter-fibrils, and in so doing, destroyed the crosslinks.
Calcific metamorphosis is seen commonly in the dental pulp after traumatic tooth injuries and is characterized by deposition of hard tissue within the root canal space. Opinion differs among practitioners as to whether to treat these cases upon early detection of calcific metamorphosis or to observe them until symptoms or radiographic signs of pulpal necrosis are detected. In this article, the clinical, radiographic, and histopathologic appearance of calcific metamorphosis is described; a review of the literature is presented to address these issues in an attempt to establish sound rationale for treatment. Approximately 3.8% to 24% of traumatized teeth develop varying degrees of calcific metamorphosis. Studies indicate that of these, approximately 1% to 16% will develop pulpal necrosis. Most of the literature does not support endodontic intervention unless periradicular pathoses is detected or the involved tooth becomes syptomatic. It may be advisable to manage cases demonstrating calcific metamorphosis through observation and periodic examination. A report of a case where in non-surgical endodontic intervention was successfully carried out a patient suffering from calcific metamorphosis with periapical pathoses is also presented.
Using backscattered electron (BSE) imaging and scanning electron microscopy, subsequent to a combined treatment of sodium hypochlorite (NaOCl) and ethylenediamine tetra-acetic acid (EDTA) or only with EDTA etching, we observed some structures of non-collagenous calcified matrixes with the aim of revealing the correlation of deposition between calcification degree and organic amount. In human tooth enamel, the NaOCl-EDTA method eroded more intensively the hypocalcified prisms of enamel tufts containing a relatively large amount of EDTA-insoluble organic matter than the hypercalcified normal prismatic enamel containing a small amount of the organic matter. Afibrillar cementum, one of the non-collagenous calcified tissues similar to the enamel, has been reported to consist of organic-rich and poor incremental lamellae. The BSE imaging showed an alternation pattern of hypocalcification and hypercalcification. The hypocalcified lamellae were retained by EDTA etching, while the hypercalcified lamellae showed a resistance against the NaOCl-EDTA method. In the non-collagenous calcareous concretions of human pineal body, organic-rich and poor, and hyper- and hypocalcified incremental lamellae have been reported. The deposition pattern of calcification degree and organic amount was similar to that in afibrillar cementum, and the hypercalcified lamellae showed a resistance against the NaOCl-EDTA method. In conclusion, the high and the lower calcified regions of non-collagenous calcified matrixes contained smaller and larger amounts of EDTA-insoluble organic matter respectively. Moreover, scanning electron microscopy subsequent to the NaOCl-EDTA method corresponding to the BSE imaging clearly showed fine calcified structures compared with the BSE imaging.
The specific properties of mineralized tissues are defined by the composition of the fraction of the noncollagenous matrix proteins. Because these proteins play a pivotal role in the processes of cell differentiation and activation and of mineralization, their temporal and spatial expression is tightly regulated. Within this study, the expression of the enamel protein amelogenin and of the bone matrix proteins osteopontin, bone sialoprotein, osteocalcin, and osteonectin was investigated by in situ hybridization. Two models that allow observation of the formation of mineralized tissues were chosen. The development of bone and cartilage was observed on murine metatarsals from 15-day-old embryos up to 1-day-old mice. This time covers the periods of initial bone formation as well as onset of resorption of mineralized cartilage and bone. To study gene expression in the mineralized tissues of the dental organ, enamel, dentin, and cementum, developing molars ranging in age from 16-day-old embryos to 14 days after delivery were chosen. Within this time frame, the molars develop from an immature state to the differentiated organ which erupts through the mandibular bone. In the developing metatarsals, osteopontin and bone sialoprotein mRNAs were detected in osteoblasts and hypertrophic chondrocytes at the onset of mineralization. In the tooth organ, only cementoblasts expressed transcripts encoding the two proteins; odontoblasts and ameloblasts did not express these genes. Osteonectin was expressed by osteoblasts and hypertrophic chondrocytes as well, whereas in the molars it was produced exclusively by odontoblasts. Osteocalcin was expressed specifically by osteoblasts in the developing metatarsals. In tooth, osteocalcin transcripts were detected in odontoblasts. Finally, amelogenin was a specific product of ameloblasts. Thus, a sequential and cell type-restricted expression of matrix proteins takes place during the development of the mineralized tissues. The expression patterns of the transcripts encoding the bone matrix proteins suggest different biological roles depending on the time and site of expression.
In dentinogenesis, certain growth factors, matrix proteoglycans, and proteins are directly or indirectly dependent on growth hormone. The hypothesis that growth hormone up-regulates the expression of enzymes, sialoproteins, and other extracellular matrix proteins implicated in the formation and mineralization of tooth and bone matrices was tested by the treatment of Lewis dwarf rats with growth hormone over 5 days. The molar teeth were processed for immunohistochemical demonstration of bone-alkaline phosphatase, bone morphogenetic proteins-2 and -4, osteocalcin, osteopontin, bone sialoprotein, and E11 protein. Odontoblasts responded to growth hormone by more cells expressing bone morphogenetic protein, alkaline phosphatase, osteocalcin, and osteopontin. No changes were found in bone sialoprotein or E11 protein expression. Thus, growth hormone may stimulate odontoblasts to express several growth factors and matrix proteins associated with dentin matrix biosynthesis in mature rat molars.
Teeth of seven patients from the Brandywine isolate who had dentinogenesis imperfecta (DI) type III were evaluated by clinical, radiologic, and scanning electron microscopic techniques. The deciduous and permanent teeth were opalescent, and there was marked attrition. Enamel pitting was present on some permanent teeth. Anterior open bites were found in all persons with complete permanent dentitions. Pulps of developing teeth were larger than normal during early development but rapidly became almost completely obliterated. There was increased constriction at the cementoenamel junctions. While radiolucencies were noted at the apices of teeth which had pulp exposures due to attrition, several patients had similar radiolucencies which could not be attributed to caries or attrition. Scanning electron microscopy showed a significant reduction in the number of dentin tubules on fractured dentin surfaces; calcospherites at the calcification front were either irregularly shaped or absent. A single tooth from a patient with DI type II was studied and had similar abnormalities on scanning electron microscopy, although tubules were easier to find and calcospherites at the calcification front were more regular than in DI type III. The findings in DI type III of enamel pitting, enlarged pulps early in tooth development, and radiolucencies at the apices of teeth without pulp exposures support the hypothesis that DI type II and DI type III are different disorders.
OBJECTIVE: For the purpose of supplementing the shortage of dental information about DiGeorge syndrome, we report two cases of the syndrome seen in Japanese boys. STUDY DESIGN: Two cases were compared with respect to orofacial and dental findings; one was a case of complete DiGeorge syndrome and the other a case of partial DiGeorge syndrome. Extracted deciduous teeth from the two boys underwent histologic study. RESULTS: Each patient showed systemic developmental delay, hypocalcemia, and slight mental retardation. In the orofacial area, hypertelorism, a short philtrum, thick and reflected lips, and hypoplasia of the nasopharynx were also observed. A dental examination showed delayed formation and eruption of permanent teeth, aplasia of the nasopharynx, and enamel hypoplasia along with enamel hypocalcification. Structural streaks with increased calcification were histologically detected in the deciduous tooth from the patient with complete DiGeorge syndrome. CONCLUSIONS: Common characteristic orofacial and dental findings were noted in the two DiGeorge syndrome cases. Furthermore, histologic study of the deciduous tooth from the boy with complete DiGeorge syndrome suggests that there was some relationship between transient relative hypercalcemia and dentinal hypermineralized streaking of the tooth.
This case report describes a rare case of an adenomatoid odontogenic tumor (AOT) arising in the mandibular third molar region of a 20-year-old female. The tumor was a well-circumscribed intraosseous lesion with an embedded tooth. Histologically, the induction of extensive globular calcification was evident in addition to the characteristic histological features of AOT. The present case lends support to the categorization of AOT as an odontogenic tumor consisting of a disorderly mixture of odontogenic epithelium and odontogenic ectomesenchyme with calcification.
Intentional replantation is an accepted endodontic technique for treating teeth in which both conventional and/or surgical endodontic treatments are not recommended. A rare case using intentional replantation technique on one mandibular molar has been successfully treated. This procedure was used owing to inaccessible calcified canal and pain intolerance of the patient. A thirty month post-operative evaluation revealed an asymptomatic, functional tooth with no radiographic signs of pathosis. The favorable results obtained in this case might be attributed to certain factors, such as occlusal adjustment prior to replantation, maintaining asepsis during replantation, no-damaging pressure during extraction, use of noneugenol periodontal packing, preservation of the vitality of the periodontal ligament, a minimal extraoral period, non-rigid splinting, apicoectomy and retrograde amalgam filling were done for hermetic apical seal. Intentional replantation may be limited to those cases when conventional endodontic therapy is not possible, but may be a treatment alternative to maintain the dentition and save an otherwise hopeless tooth.
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We have presented a case in which 3.7-year-old patient exhibited calcific metamorphosis of a maxillary primary central incisor at the initial visit, with subsequently internal resorption developing in the same tooth. This case underscores the need for careful monitoring of traumatized teeth that have undergone calcific metamorphosis.
Five methods for the treatment of teeth with an incompletely formed apex (open apex) and a necrotic pulp are discussed. The methods discussed include the use of (1) a customized cone (blunt-end, rolled cone); (2) a short-fill technique; (3) periapical surgery (with or without a retrograde seal); (4) apexification (apical closure induction); and (5) one-visit apexification. The apexification techniques, which use various formulations of calcium hydroxide to induce closure, are stressed. Based on the review of the literature and clinical experience of the authors, it was concluded that successful treatment of an immature pulpless tooth can partly result from the antibacterial and calcification-inducing action of calcium hydroxide.