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At least 19 recordsLinked to original sources
PubMed1990

[Experimental study of bone resorption after tooth extraction with implanted hydroxyapatite tooth root substitute].

Hydroxyapatite (HAP) tooth root substitute implantation have been applied to extraction sockets in many studies for purpose of preservating alveolar bone. Dimensional changes were measured with sectioned study cast of cephalometric X-ray photo. In this study, dimensional changes were determined by newly developed evaluation system which utilizing image analyzer (Immunomedica Co., Ltd.), in a view of conserving alveolar ridges beneath the denture base. Cone shaped HAP tooth roots (5 or 6 mm in length) were implanted to one subject and disk-like shaped HAP tooth roots (2 mm in length) were also implanted to the other subject. Preservation of alveolar bone was observed in both shaped HAP tooth roots implanted site compared to control site. Bony ankylosis between HAP tooth root and alveolar bone, observed on 1 month after histological specimens, may contribute to this result. Smaller changes of blood flow compared to controls were obtained on implanted site, which were measured with Laser Doppler blood flow meter (Perimed KB; Sweden) on buccal mucosa. We consider that HAP shows good biocompatibility and HAP tooth roots implantation decrease the wound volume consequently.

Alveolar Bone Loss↗
PubMed1992

Comparison of phosphoprotein isolated from mature and immature human tooth roots.

Mature (average patient age = 29.5 yr, closed apical foramen) and immature (average patient age = 17.5 yr, open apical foramen) root shards were placed in dialysis tubing and demineralized to completion using either 10% disodium EDTA plus protease inhibitors or 0.6 N HCl. The demineralized shards were re-extracted (five times) with 0.05 M tris-HCl, 1.0 M NaCl and then collagenase digested. No major differences were observed in chromatograms of extracts, re-extracts or collagenase digests from root shards demineralized in either way. In contrast, chromatograms of immature and mature roots showed qualitative differences. Chromatograms of mature roots demineralized in either way showed broader protein peaks and less organic phosphorus than those from immature tooth roots. A distinct band amid degraded phosphoprotein (150 K) was found in SDS-PAGE gels (7.5%) from EDTA-extracted immature tooth roots but not from mature tooth roots. Electroelution of this band revealed a typical phosphoprotein amino-acid profile containing increased aspartic acid and serine residues. Comparison of the total phosphoprotein and amino acid composition of extracts, re-extracts and collagenase digests revealed that phosphoprotein, serine and to a lesser extent aspartic acid were recovered in greater quantities from immature roots than mature tooth roots. These data suggest that the degree of maturation is crucial to the isolation of an intact phosphoprotein and provides additional evidence that human dentine phosphoprotein undergoes amino acid compositional changes during maturation.

Adolescent↗
PubMed1988

The tooth-root sign: a characteristic appearance of distal ureteric calculi.

Diagnostic accuracy in identifying calculi in patients with ureteric colic is poor. Lower ureteric calculi may be confused with other pelvic calcific opacities. A characteristic appearance of some larger lower ureteric calculi is described and likened to the root of a tooth. It is hoped that the tooth-root sign will be of assistance in the diagnosis of distal ureteric stones.

Humans↗
PubMed1979

Tissue reaction to submerged ceramic tooth root implants. An experimental study in monkeys.

Tooth root replica implants made from alumina ceramic material of solid structure coated with a porous layer, were used as dental implants in monkeys. The porous coating was 1/2 mm thick and had pore sizes within 50--200 microns range, with a 30% degrees of porosity. Tne implants were inserted into prepared sockets in the mandible of 5 Cercopithecus monkeys. After submerged implantation periods varying from 5 to 15 weeks, a perforating steel post was introduced through the covering gingiva into the artificial root canal of the implants. The animals were sacrificed after 6 weeks, 2, 3 and 4 months. Three out of the total number of 10 implants were lost. The remaining 7 specimens were retrieved for histologic and microradiographic examination. Fibrous and mineralized tissue ingrowth of the porous layer of the implants was found. No adverse reactions of the adjacent bone were demonstrable. The implants became anchored to the host and no epithelial downgrowth along the ceramic was found.

Aluminum Oxide↗
PubMed1988

The relationship of the periodontal status to fluoride levels of alveolar bone and tooth roots.

The periodontal status and fluoride levels of alveolar bone and tooth roots were compared for subjects from a high (2.5 ppm F) and a low (less than 0.05 ppm F) fluoride area. The plaque index, gingival index, probing depth and loss of attachment were measured to determine the periodontal status. The fluoride levels were determined by the use of the fluoride ion-selective electrode. Both communities had high plaque and gingival indices. However, the mean pocket probing depths in both communities were less than 2.5 mm. No statistically significant differences could be found in the periodontal status between the 2 areas. The fluoride levels in bone and root were higher for subjects from the high fluoride area. No statistically significant difference could be demonstrated between the fluoride levels in alveolar bone and tooth roots for each area. It was found that the fluoride levels in bone and roots increased with increasing age, but to a lesser degree for subjects from the low fluoride area.

Adolescent↗
PubMed1976

Polymer-ceramic composite for tooth-root implant.

A new polymer-ceramic composite suitable for tooth-root implants has been developed in this study. This material exhibited the desirable combination of good mechanical properties, controlled porosity, and ease of processing. A thermal processing technique was utilized to polymerize acrylic acid (AA) in the presence of either 0.3 or 0.05 mu alumina particles. Porosity and pore size distribution were influenced by the alumina particle size and the processing technique. For a 50 vol % AA solution, the composite had an average compressive strength of 18,000 psi and 38% porosity when 0.3 mu filler particles were used. In comparison, the 0.05 mu alumina-filled composite had an average compressive strength of 28,000 psi with a 15% porosity. Data on the physical and structural characteristics of the composite are presented in this study. Based on these results, the composite material shows good potential for use in tooth-root implants as well as other orthopedic implant applications.

Absorption↗
PubMed1990

A computer-aided image analysis system for area measurement of tooth root surfaces.

The characteristics of a computer-aided Image Analysis System (IAS) to conduct linear and area measurements on tooth root surfaces were investigated. The borders of the features to be measured were extracted from a digitized video image by histogram-based thresholding and binarization. The lengths and square areas were expressed in the number of pixels. The reference-length and area of one pixel were obtained through measurement of the diameter of a metal ball of known diameter in the same digital image. The validity of the IAS was tested using radiographs of teeth containing round metal restorations of known diameter and area. The accuracy of the length measurements ranged from -2.0 to 2.1%, whereas the accuracy of area measurement was between -5.3 and 0.8%. The precision of the IAS to identify the borders of a tooth root surface and to reproducibly calculate its area, expressed in a coefficient of variation, ranges from 0.49 to 4.11%. The results indicate that imaging techniques can be applied to obtain very accurate measurements of tooth root surfaces.

Dental Enamel↗
PubMed1990

An immediate tooth root replacement: an implant cylinder and synthetic bone combination.

Tooth extractions in 22 cases were treated immediately with the simultaneous placement of a cylinder implant and injection of particulate synthetic bone around the neck of the implant and into the extraction socket surrounding the cylinder. Preliminary results indicate a success rate of 94.1% in those implant/synthetic bone combinations placed in function. The utilization of synthetic bone in combination with an implant creates the possibility of an immediate tooth root replacement. Besides replacing a "lost part" of the jaw immediately, this practice prevents the normal 40% to 60% bone loss that occurs in the two years post-extraction and improves both function and aesthetics for the patient. The synthetic bone, HTR Polymer, was used in combination with Steri-Oss cylinders.

Alveolar Bone Loss↗
PubMedDate not supplied

[Radiographs and tooth roots in maxillary sinus].

Roentgenographic observations in 19 cases of tooth roots displacement to the maxillary sinus using 4 technics of periapical, topographic, Waters and panoramic projection. It was indicated that, 1). Left maxillary first molar root was forced into the antrum more frequently than the roots of other teeth. 2). Roots were displaced into sinus more frequently in males than females. 3). To identify the root, panoramic and topographic were helpful projection. Waters projection was of little or no value, for the root fragment. However it is useful in that it may provide indirect confirmatory evidence of an antral perforation and reveals the presence of sinus infection.

Female↗
PubMed1989

Tooth root resorption induced in rats by diphenylhydantoin and parathyroidectomy.

Changes in bone, cartilage and the dentition in animals and man following the administration of anticonvulsant drugs resemble those seen in hypoparathyroidism and pseudohypoparathyroidism. Groups of 21-day-old rats were treated with diphenylhydantoin, parathyroidectomized, or made hypocalcaemic with a calcium-deficient diet. Histological examination revealed extensive resorption of cementum and dentine in the molars of the drug-treated and parathyroidectomized rats, but not in the hypocalcaemic or control groups. Localization of injected tetracycline by fluorescence showed that the resorption affected the distal side of the tooth roots and had occurred after root formation. No changes in cementum formation on the mesial side of the roots had occurred in any of the experimental groups. These results suggest that diphenylhydantoin induces a condition similar to pseudohypoparathyroidism in which the resistance of tooth roots to resorption is reduced.

Animals↗