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PubMed1991

A review of aging of dental components and a retrospective radiographic study of aging of the dental pulp and dentin in normal teeth.

A review of aging of dental components is followed by a clinical radiographic study. Patients received radiographs at 5-year intervals with a 10-year minimum followup. Data obtained were age, gender, tooth, and systemic diseases. Measurements taken were tooth length, coronal length, apical length, cervical width, midroot width, and apical width. Root canal shrinkage was calculated vertically, horizontally, and as a combination (vertical and horizontal). Results showed statistically significantly more shrinkage in men, the elderly, and people with calcification-related diseases. Shrinkage increased with advancing age. With further studies, radiographically determined root canal measurements could prove useful in anthropology, forensics, and as a biomarker of aging.

Adult↗
PubMed1996

Bone surface morphology reflects local skeletal metabolism.

The metabolic activity of bone cells is faithfully reflected in the surface topography of mineralized bone surfaces, and this can be easily detected by scanning electron microscopy (SEM). Forming bone surfaces exhibit knobby projections which represent foci of mineralization, resorbing surfaces are scalloped, and resting surfaces undergoing neither activity are smooth, as shown by Boyde and Hobdell 25 years ago. These phenomena are illustrated in vivo by tooth eruption, a local activity in alveolar bone where resorption and formation are polarized around an erupting tooth, and osteopetrosis, a metabolic bone disease characterized by a congenital reduction or absence of bone resorption. The ability to analyze bone metabolism over large areas of the skeleton by SEM offers a convenient and powerful microscopic technique to assess regional and global bone cell activity in an era where the investigative focus is increasingly molecular.

Animals↗
PubMed1988

Morphological changes in the oral (buccopharyngeal) membrane in urodelan embryos: development of the mouth opening.

The ultrastructure of the oral (buccopharyngeal) membrane in the embryo of the urodelan, Hynobius tokyoensis, was examined by transmission (TEM) and scanning electron microscopy (SEM). The oral membrane consists of the stomodeal ectoderm and foregut endoderm, and is three to five cell layers thick at stage 24. The oral membrane gradually thickens as development proceeds. The stomodeal collar, derived from the ectoderm, is folded inward along the foregut endoderm. Tooth germs are formed partly by cells of the stomodeal collar and partly by mesenchymal cells and calcification takes place before hatching. Secretory granules, which are markers of epithelial differentiation, appear in some cells of the foregut endoderm. Within the oral membrane, the cells of the stomodeal collar become the basal cells, and the endodermal cells of the foregut become the apical cells of the future oral epithelium. Gaps are formed by the epithelial differentiation of the endodermal cells of the foregut in the oral membrane. The gaps connect with each other, with the stomodeum, and with the foregut. As a result of these events, the mouth opens at stage 43, just after hatching.

Animals↗
PubMed2004

[Calcifying epithelial odontogenic tumor of the maxilla (Pindborg tumor)].

A male patient presented with an extraordinarily large calcifying epithelial odontogenic tumor (CEOT or Pindborg-tumor) that affected the maxilla. The disease became evident due to alterations in the facial aspect, in particular of the perioral region, caused by the expanding tumor. CEOT is characterised by the slowly growing mass of part of the jaws. Multilocular or extraosseous manifestations are extremely rare. Malignant transformation with metastases is rare. Radiography depicts characteristic, but not obligatory, areas of calcification inside the tumor. The surgical therapy for CEOT is complete local resection with safe margins. If tooth bearing parts of the jaws are affected, these teeth almost always have to be removed. The prognosis is excellent for overall survival. Local recurrences have rarely been reported but may be found even decades after primary treatment. Three years following surgical therapy there is no evidence of local recurrence. A long-term follow-up control is recommended.

Calcinosis↗
PubMed1994

Root resorption and pulpal changes due to intrusive force.

Intrusion has been regarded as a controversial topic in the literature. It is apparent from many studies that excessive forces applied in orthodontic treatment might lead to undesirable results such as circulatory disturbances, pulp degeneration, calcification and even necrosis. This study was performed to observe the reaction of pulp and roots following tooth intrusion. Material consisted of four first premolar teeth of two adult patients. One premolar of each patient was intruded orthodontically and the other premolars were taken as controls. The palatal roots of the experimental teeth were cut and examined in scanning electron microscope (SEM) and the pulps of the teeth were examined in transmission electron microscope (TEM). At SEM examination, root surfaces of intruded teeth showed resorption cavities of different diameters and depths. At TEM examination, vascular degeneration was the main change in the pulps of experimental teeth.

Adult↗
PubMed2005

Case report of a rare syndrome associating amelogenesis imperfecta and nephrocalcinosis in a consanguineous family.

A rare syndrome associating amelogenesis imperfecta (AI) with nephrocalcinosis has been reported. The purpose of this study is to characterise the phenotype of a consanguineous family presenting amelogenesis imperfecta, delayed permanent teeth eruption and nephrocalcinosis. Six family members were examined. Ground sections of the case index deciduous teeth and biopsies of enlarged dental follicles were analysed. The patients's parents were first cousins. The case index had yellow discoloration and altered teeth shapes, retention of deciduous teeth, and delayed eruption. Panoramic radiographs revealed multiple enlarged pericoronal follicles in unerupted teeth and generalised intrapulpal calcifications. Renal ultrasound showed the presence of nephrocalcinosis. No other family members presented enamel defects or nephrocalcinosis. Histologically, the enamel appeared hypoplastic, and dental follicles indicated pericoronal hamartoma. The consanguineous marriage suggests an autosomal recessive mode of inheritance. Further studies are necessary to clarify the genetic defect behind this syndrome that associates AI, nephrocalcinosis and impaired tooth eruption.

Adolescent↗
PubMed2005

[Age estimation of children in south-western Hungary using the modified Demirjian method].

The biological age of a child, in contrast to his or her chronological age, may be described in terms of skeletal or dental maturity, the development of secondary sex characters etc. These factors can be applied separately or together to assess the degree of physiological maturity of a growing child. The determination of this physiological age and its correlation to the chronological age is of importance within many fields, such as archaeology, forensic medicine, endocrinology, orthodontics etc. Dental maturity was studied on 203 panoramic radiographs, taken between 1985 and 1995, of healthy Hungarian children aged 2.9 to 17.5 years from the south-west Transdanubian part of Hungary. The revised method of Demirjian was used for determination of the maturity score of each individual. For each tooth a score (on a scale A-H) was given according to the radiographic development, from first appearance of calcification to the closure of the apex. This score was then transformed into a self-weighted maturity score for the dental stages (0-19.3) as presented in the paper. The individual scores were then added giving a total maturity score (0-100). This total maturity score represents the biological maturity of the child and may then be compared with the known chronological age. The total maturity scores of the Hungarian population was plotted against the chronological (real) age, and a curve was fitted using the Lowess method of locally weighted least-square method. Our results show that each population needs its own standards. Hungarian boys and girls are approximately 1 year ahead of their French-Canadian counterparts at the age of 6-8. At older ages, the difference decreases. Similar to other studies, we found high individual variance up to 2 years, in tooth development, in the Hungarian population.

Adolescent↗
PubMedDate not supplied

Pulp-dentin biology in restorative dentistry. Part 5: Clinical management and tissue changes associated with wear and trauma.

Tooth wear occurs during normal mastication. Pathologic wear, including abrasion and erosion, may also take place. Formation of reactionary and reparative dentin and obturation of dentinal tubules are biologic responses that compensate for the loss of tissue. Physical trauma to teeth will affect the blood supply to the pulp. Extensive physical trauma may result in the formation of mineralized, often bonelike tissue in the pulp chamber. Minor trauma, such as that associated with orthodontic tooth movement, may exert transient effects on the pulp or it may result in permanent structural changes. No experimental data involving restorative work on traumatized teeth have been published, but available evidence suggests that special care may be necessary in the restoration of such teeth because their reaction patterns may differ from those in nontraumatized teeth.

Dental Deposits↗
PubMed1997

The mineralization of mantle dentine and of circumpulpal dentine in the rat: an ultrastructural and element-analytical study.

The purpose of this study was to compare the biomineralization of circumpulpal dentine with that of mantle dentine by ultrastructural and element-analytical techniques. Forty upper second molar germs of 10-day-old albino rats were cryofixed in liquid nitrogen-cooled propane and embedded in resin after freeze drying. Semithin dry sections were cut for analyzing the calcium and phosphorous concentration in initial mantle dentine, at the mineralization front of circumpulpal dentine, in the middle region of circumpulpal dentine and in mantle dentine peripheral to circumpulpal dentine. For the morphological evaluation of mineral deposits we compared ultrathin and unstained sections of cryofixed molars with chemically fixed molars. For both dentine types it was found that they develop via identical steps of mineral formation at collagen fibrils and non-collagenous matrix molecules. In circumpulpal dentine no globular mineral protrusions along the mineralization front (i.e. calcospherites) and no indications of interglobular dentine at the transition from circumpulpal dentine to mantle dentine were present. Two von Korff fibres were not only visible in mantle dentine but also in circumpulpal dentine. Matrix vesicles were present only during the formation of an initial coherent layer of mantle dentine and could not be observed during successive formation of mantle dentine and circumpulpal dentine. The element-analytical data did not demonstrate any difference in the mineral content between the two dentine types. Therefore, we conclude that mantle dentine and circumpulpal dentine in the rat molar possess a high degree of structural and chemical similarity and that only the extent of terminal branching of the odontoblast processes gives an approximate estimation of the thickness of mantle dentine.

Animals↗
PubMed1990

Comparison of the radiographic appearance of root canal size to its actual diameter.

Clinically, the apparent radiographic diameter size does not always seem to correspond to the true canal size. The objective of this study was to compare canal size on periapical radiographs with the actual canal diameter as determined histologically. Periapical radiographs were exposed on 36 teeth on 5 human cadavers. Mesial-to-distal boundaries of canals were measured in the cervical, middle, and apical thirds. The teeth were extracted, the roots histologically processed, and cross-sections made in the cervical, middle, and apical thirds. Measured values of diameter from radiographs were compared with true canal widths as measured from the corresponding level of histological sections by using a correlated t test. All sections of all roots demonstrated a canal histologically, although some regions had no canal visible radiographically. In general, there was statistically no difference (p less than 0.001) between the histological and radiographic measurements even when pulpal calcifications were present. However, in some roots there were marked discrepancies between radiographs and histological sections as to canal diameter.

Dental Pulp Calcification↗
PubMed1989

Brushite in the pulp of primary molars.

This study was undertaken to investigate the mineral phase of spherulitic calcifications discovered in the pulpous mesenchyme of human primary molars by microradiography. Analytical scanning electron microscopy and x-ray diffraction disclosed that well-crystallized brushite is the major compound of the spherulites. The mechanism leading to the crystallization of brushite is far from well understood. Histologically, on decalcified sections, inflammatory cells and capillaries can be seen trapped in the spherulites. In the light of these findings, it could be suggested that metabolic conditions may promote the crystallization of brushite in the pulp of primary molars.

Adolescent↗
PubMed1977

The role of bone remodelling in the healing of extraction socket in rats.

Bone remodelling of post-extraction socket was studied in the past by various methods. In the present work, the process was studied with the scanning electron microscope (SEM). The SEM is essential for a three-dimensional description, particularly when hard tissues are involved. Initiation of healing on the first week was characterized by formation of delicate spongy bone. The trabeculae were distributed in a centrifugal pattern around the interradicular bone. Socket healing on the second week consisted of thickened, regularly distributed trabeculae. This was accompanied by resorption and flattening of the peri-socket sharp ridges. The third and fourth weeks were characterized by small bone marrow spaces and a gradual transformation of the trabecular bone to one of cortical-compact nature. The typical characteristics of resorbing, resting and forming surfaces were detected in all phases of socket healing. Two major patterns of ossification could be shown: Firstly, calcification of collagen bundles in osteoblastic lacunae. Concentrations of such lacunae were related to periosteal activity and were also found in areas most probably occupied previously by blood vessels. Another pattern of mineralization was in the form of globular calcospherites and is reminiscent of calcification of ground substance.

Alveolar Process↗
PubMed2006

Taurodontism of deciduous and permanent molars: report of two cases.

Taurodontism is an aberration of teeth that lacks the constriction at the level of the CEJ characterized by elongated pulp chambers and apical displacement of bifurcation or trifurcation of the roots, giving it a rectangular shape. Its occurrence in permanent teeth is common and is quite rare in deciduous dentition. Presented in this article are two cases with taurodontism involving deciduous and permanent molars.

Child↗