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At least 253 records · Page 14Linked to original sources
PubMed1987

The mineral solubility of human tooth roots.

Whole roots of molars that had never been exposed to the mouth were exposed to calcium and phosphate-containing buffer solutions with discrete values of pIOHA [i.e. -log(a10Ca2+ X a6PO4(3-) X a2OH-)] at various pH. From densitometric measurements on contact-microradiographs of transverse sections of the roots the rate of demineralization (Vdem) was calculated. Vdem changed non-linearly as a function of pIOHA and became zero at a pIOHA-value of 105.3 +/- 0.4; this is substantially lower than the corresponding value of 118 +/- 1 for enamel. Thus root mineral is more soluble than enamel mineral. The critical pH for root caries appears to be about 6.7, provided that the plaque fluid follows about the same pH-pIOHA- pathway as acidified saliva.

Adult↗
PubMed1991

[Investigations of centrifugal penetration of the tooth root hard substances by hydrogen peroxide].

After application of hydrogen peroxide into the root canal of extracted teeth of patients between the ages of 18 and 30 years the antiseptic could be detected on the root surface by means of iodometry and in tooth cross sections in dentine and cementum by means of staining reaction (benzidine-peroxidase solution). Out of the root canals which were apically not passable and coronally closed the first traces of the instilled 5% hydrogen peroxide appeared after 14 min 45 sec on the root surface. In the dentine a mean penetration depth of hydrogen peroxide up to 1.28 mm (apical root area), 1.45 mm (middle root third) and 1.95 mm (coronal root area) could be measured. Best results were obtained after rinsing/suction treatment of the root canal, especially in combination with low-frequency ultrasound.

Adolescent↗
PubMed1989

[Radico-diagram: a technic for study of tooth root].

The use of a simple measuring system such as the root diagram provides us with information about the morphology and the inclination of the roots of dental pieces. This system applied on x-rays taken with accurate and adequate techniques facilitates and enables one to study extensive groups of the population with common or divergent ethnic features and their subsequent comparative analysis.

Dental Pulp Cavity↗
PubMed2004

[The cat with exposed tooth roots: a missed diagnosis?].

The distal roots of the mandibular molars (309 & 409) are often exposed in cats with chronic, recurrent inflammation of the oral mucous membranes. The disorder can be easily detected during a thorough investigation under light sedation. Some reasons are given why the diagnostic investigation is sometimes performed incompletely.

Animals↗
PubMed1989

[Ultrastructural study of initial attachment by human fibroblast-like cells on tooth roots in vitro].

The purpose of this study was to determine the longitudinal effect of demineralized treatment of root surfaces on initial attachment, growth and differentiation of human periodontal ligament fibroblast-like cells in vitro. Cementum and dentin fragments were prepared from intact extracted human teeth for orthodontic reason. The root fragments of one group were not demineralized. Those of the other groups were demineralized by either citric acid (pH = 1.0, 3 min) or EDTA (pH = 7.4, 30 min). Plastic sheets served as controls. Human periodontal ligament fibroblast-like cells were incubated on root fragments and plastic sheets. After incubation, the root fragments and plastic sheets were examined by electron microscopy. The collagen fibers were exposed to the root surface by demineralized root surface. The exposed collagen fibers showed an effect on the cell attachment and growth, and the cells produced collagen fibers in the extra-cellular space of the root surface. Demineralization of dentin fragments were more strongly affected in cell attachment, growth and differentiation than demineralization of cementum fragments. Citric acid demineralization of dentin fragments had a greater effect on cell attachment, growth and differentiation than EDTA demineralization of dentin fragments. The results suggest that citric acid demineralization of dentin fragments may provide the most effective dental surface for the establishment of connective tissue attachment after periodontal treatment.

Citrates↗
PubMed1983

The development of a novel tooth-root implant material.

Polyacrylic acid-alumina composites have been developed in this laboratory and were found to be biocompatible and resistant to biodegradation. These composites can be designed to apply a predetermined pressure on the bone interface which was found beneficial for stimulation of new bone formation and increased bone densification at the implant interface. Optimization of the physical and mechanical properties is presented, and a brief summary of the subcutaneous and oral implantation is reported.

Acrylic Resins↗
PubMed1999

Mapping of a gene causing mouse gutter-shaped tooth root to chromosome 5.

A study was conducted to identify the major candidate chromosome and to detect the region which included the candidate gene causing gutter-shaped root (GSR) in an inbred strain of mice. The candidate chromosomal analysis was performed on genetic crosses of C57L/J strain mice, which have GSR, and C57BL/6J strain mice, which have normal roots. Linkage analysis suggested that mouse chromosome 5 was one of the major candidates and therefore this chromosome was investigated in detail by individual genotyping of all backcross mice. The highest linkage was found at D5Mit161, and other high linkages were evident at D5Mit29, 321 and 427. Based on these findings, it is suggested that the gene causing GSR formation in mice maps close to these microsatellite loci.

Animals↗
PubMed1997

Ultrastructural changes of a tooth root in young rats fed a low calcium and vitamin D-deficient diet.

The aim of the investigation was to assess the ultrastructural changes of the roots of the teeth in young rats fed a low calcium and vitamin D-deficient diet. The studies were carried out on 20 young Wistar rats. The results of the scanning microscopic observations showed the increased cementolysis and decreased mineralization of cementum and dentin in rats fed a low calcium and vitamin D-deficient diet. The results indicated that the hard tissues of the teeth, besides bony system, are also involved in calcium homeostasis in rat organism.

Animals↗
PubMed2001

Fabrication of a functionally graded dental composite resin post and core by laser lithography and finite element analysis of its stress relaxation effect on tooth root.

Laser lithography was applied for Computer Aided Design and Computer Aided Manufacturing (CAD/CAM) fabrication of dental prostheses made of composite resin. First, the conditions to obtain the optimum resolution for photo-curing were determined, and then a composite resin full crown was fabricated by laser lithography. Second, a functionally graded composite resin post and core which had gradient elasticity in the post, was manufactured by the gradual change in the filler contents of the composite resin. Finally, stress analysis of the functionally graded post and core was performed by a two-dimensional finite element method. This demonstrated the effects of reducing the stress concentration around the apex of the post.

Composite Resins↗
PubMed1999

Immunolocalization of Bone Morphogenetic Protein-2 and -3 and Osteogenic Protein-1 during murine tooth root morphogenesis and in other craniofacial structures.

The distribution of Bone Morphogenetic Protein-2, and -3 (BMP-2 and BMP-3) and Osteogenic Protein-1 (OP-1, also known as BMP-7) during root morphogenesis and in other craniofacial structures was examined in sections of 12- to 18-d-old mouse heads using polyclonal and monoclonal antibodies. BMP-3 and OP-1 were localized in alveolar bone, cementum, and periodontal ligament, whereas BMP-2 was only localized in the alveolar bone of periodontium. All three BMPs were localized in predentine, dentine, odontoblasts, osteoblasts, osteocytes, osteoid, cartilage, chondrocytes and spiral limbus. BMP-2 and OP-1 were also localized in spiral ligament and interdentate cells of the cochlea, whilst BMP-3 was restricted to the spiral ganglion. BMP-3 was also localized in ducts of submandibular and sublingual salivary glands, acini of the lacrimal gland, Purkinje cells in the cerebellum, nerve fibres of the cerebellum and brain, afferent cells of the dorsal root ganglia, inferior alveolar nerve, and peripheral processes of the vestibulocochlear nerve. OP-1 was also localized in hair and whisker follicles, sclera of the eye and in ameloblasts. The demonstration of BMP-3 in the nervous system suggests that this protein may be neurotrophic during development and maintenance of the nervous system. The composite expression of BMPs/OPs during periodontal tissue morphogenesis suggests that optimal therapeutic regeneration may entail the combined use of different BMPs/OPs.

Afferent Pathways↗
PubMed1996

The effects of CO2 laser and Nd:YAG with and without water/air surface cooling on tooth root structure: correlation between FTIR spectroscopy and histology.

Morphologic and chemical characterization of root surfaces treated with either the CO2 laser, Nd:YAG, or Nd:YAG with water/air surface cooling (Nd:YAG-C) was completed using scanning electron microscopy (SEM) and FTIR photoacoustic spectroscopy (FTIR/PAS). Specimens for morphologic analysis consisted of 20 extracted single rooted teeth unaffected by periodontal disease. The specimens were exposed at varying energy densities to a single pass of the laser. SEM examination revealed, for all lasers, a direct correlation between increasing energy densities and depth of tissue ablation and width of tissue damage. The Nd:YAG-C required higher energy densities than either the CO2 or Nd:YAG lasers to achieve the same relative depth of tissue ablation. Regardless of energy density, and in contrast with other laser types, areas treated with the Nd:YAG-C did not exhibit collateral zones of heat damage. Specimens for spectroscopic examination consisted of 12 disks, 6 x 2 mm, cut from debrided root surfaces of extracted, unerupted human molars. The spectral results indicate a substantial reduction in the absorption bands attributable to protein and an additional band at 2015 cm-1 in specimens exposed to the Nd:YAG without water. In the presence of water/air coolant, the band at 2015 cm-1 appears only at a substanially higher energy density. The spectra of the CO2 treated specimens, with the char layer present, show a significant reduction in the protein bands and additional bands at 2015 and 2200 cm-1, that are tentatively assigned to the cyanamide and cyanate ions, respectively. These results suggest a reaction of the organic matrix and mineral with laser exposure.

Acoustics↗
PubMed1996

Racial variations in the extent of tooth root translucency in ageing individuals.

One hundred and ninety-eight single-rooted teeth from individuals aged 21-90 yr of Caucasian, Malay, Chinese Malay and Indian Malay origin were studied. Single or serial longitudinal sections of extracted teeth were cut following dye imbibition of patent dentinal tubules. The extent of sclerosis of apical dentinal tubules was assessed and correlated with the age of the individual. Correlation with age was higher in the Caucasian than the Malay races and within the Malaysian racial groups correlation with age was highest in the Malays and lowest in the Chinese. It is concluded that factors other than age may be important in the formation of sclerotic apical dentine in teeth of different racial origin. The effect of racial origin should be considered when using sclerosis as a means of age determination in forensic cases.

Adult↗
PubMed1979

[Delayed eruption of the premolar after pathological deciduous tooth root resorption].

The behaviour of eruption of lower premolars after pathological resorption of deciduous molar roots was examined on models and X-rays. The molars of the first dentition were shed earlier after pathological resorption of deciduous molar roots. Data of absence are measured in years in the presence of occlusal bone bridges. The middle values are more than three years. Eruption of permanent teeth happens years later or they remain impacted. Eruption dates of premolars after pathological deciduous root resorption and interruption of the lamina dura, and after physiological resorption are significantly earlier than if there is an occlusal bony bridge (p less than 0.01). The therapeutic consequence is the surgical liberation of such premolars and their removal.

Alveolar Process↗
PubMed2002

Measurement of strain on tooth roots during post removal with the Eggler post remover.

AIM: The aim was to measure root surface strains in teeth when removing cast post/cores with the Eggler post remover. METHODOLOGY: Two groups of 10 teeth each were tested: group 1 had 1 mm thickness of dentine coronally, and group 2 had 2 mm thickness of dentine. After root filling, 10 mm long cast post/cores were constructed and cemented with zinc phosphate cement, and strain gauges were applied to the roots. The post/cores were removed with the Eggler post remover whilst strain measurements were being recorded. Posts were removed twice: initially along the long axis of the tooth and then at a 10 degrees angle to the long axis. Comparisons between groups 1 and 2 were analysed statistically with the Mann-Whitney U-test whilst strains within each group were analysed with the Wilcoxon Signed Rank test at the 95% level of confidence. RESULTS: There was no significant difference in the strains measured between groups 1 and 2, and no significant difference within each group when removing posts along the long axis of the tooth and at a 10 degrees angle. Three teeth in group 1 and one tooth in group 2 fractured when removing posts at the 10 degrees angle. Three fractures were small slivers of dentine at the point where the Eggler's repeller arms contacted the tooth mesially and distally, whilst one tooth (from group 1) fractured obliquely. CONCLUSIONS: Post removal with the Eggler device is a relatively safe procedure but care must be taken when there is a possibility of pulling the post out in a nonaxial direction or when less than 1 mm of dentine surrounds the apical end of the post.

Cementation↗