PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “TOOTH, ARTIFICIAL”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6Linked to original sources
PubMed1996

Clinical implications of recent orthodontic-periodontic research findings.

During the past 15 years, advances in basic science related to periodontal biology, and clinical trials on prevention and treatment of periodontal disease, have dramatically changed many treatment concepts in periodontics. The most pertinent information for orthodontic practice from these studies is summarized. Also, recent advances in orthodontics, particularly regarding bonding of attachments to artificial tooth surfaces and improved long-term stabilization of orthodontic treatment results in adults by means of bonded lingual retainers have significant implications. This article outlines how recent research information from both dental specialties may be used by orthodontists to improve treatment planning, clinical management, and retention of their adult and elderly patients in whom different malocclusions are complicated by moderate to advanced periodontal destruction.

Adult↗
PubMed2001

Relationship between the stress distribution and the shape of the alveolar residual ridge--three-dimensional behaviour of a lower complete denture.

PURPOSE: For a complete denture to function effectively, the denture must be stabilized during mastication. The alveolar ridge has various forms, and we must choose the artificial tooth arrangement that is most suitable to the form of the alveolar ridge. The purpose of this study was twofold: (i) to examine the relationship between the alveolar ridge form and the stress distribution on the mucosa, and (ii) to model the contact condition between the denture base surface and mucosa. MATERIALS AND METHODS: In this study, the three-dimensional finite element method was used for the analysis. Four types of alveolar ridge were prepared. As a loading condition, three load places were prepared: the mesial position, the central position and the distal position. We utilized the 'contact option (MARC)' to simulate the true behaviour of the denture. RESULTS: We were able to model the contact condition by using the 'contact option'. Maximum stresses were distributed on the alveolar ridge in which the absorption is severe. And, the distal load produced large compressive stresses on the inclined plane of posterior alveolar ridge in which alveolar form.

Alveolar Bone Loss↗
PubMed2000

Relationship of intracanal pressure with viscosity of endodontic sealer during warm Gutta-Percha vertical compaction.

OBJECTIVE: To test the association between endodontic sealer viscosity and intracanal pressure during warm gutta-percha vertical compaction. STUDY DESIGN: An artificial tooth model and pressure-sensing apparatus were developed so that reproducible, quantitative measurements could be determined. Intracanal pressure was measured at 3 phases of obturation: cone insertion, heat application, and force application. Samples were randomly assigned to 3 sealer viscosity groups (most viscous, normal, least viscous) and to a no-sealer group. Evaluations were blinded to group assignments (4 groups, 15 samples per group). RESULTS: Differences in intracanal pressure were detected between sealer viscosity groups. The most viscous group had the largest intracanal pressure. Throughout the phases of obturation, intracanal pressure did not remain constant; values at the time of heat application were lower than at cone insertion and force application. CONCLUSIONS: The results indicate that intracanal pressure increases as sealer viscosity is increased, and that intracanal pressure does not remain constant during obturation.

Analysis of Variance↗
PubMed1993

Longitudinal study on occlusal force distribution in lower distal-extension removable partial dentures with conus crown telescopic system.

The purpose of this study was to examine longitudinal changes of the occlusal force distribution in lower distal-extension removable partial dentures with the conus crown telescopic system. Occlusal force applied to the denture and forces transmitted to the retainers were measured on several separate occasions from the insertion of new dentures to about 3 months after. The occlusal force distribution ratio to the retainers was calculated when a load of 20 N was applied to the denture. The results are summarized as follows: (i) The more posterior the loading point of occlusal force, the smaller was the ratio. When the occlusal force was applied to the most anterior artificial tooth, the ratio was 65-100% of the occlusal force. (ii) As the denture wearing time proceeded, the ratio was decreased. The smaller the ratio, the greater was the rate of its decrease.

Aged↗
PubMed1975

Early formation of dental plaque on platic films. 1. Light microscopic observations.

In human subjects with healthy gingiva thin transparent plastic films were applied to the buccal surfaces of premolars in the upper and lower jaws. The films were left in place for peiods of 15, 30, 60, 120 and 240 minutes. The presence of coccoid bacteria, leukocytes and epithelial cells was investigated in an area adjacent to the gingival margin. The results showed that by 15 minutes coccoid bacteria had become attached to the artificial tooth surface. The number of microorganisms gradually increased during the time of the study. Large numbers of cocci and the formation of micro-colonies were observed after 120 and 240 minutes. Increasing numbers of leukocytes and epithelial cells were also found during the period of observation.

Adult↗
PubMed1986

Isolation and characterization of a 60-kilodalton salivary glycoprotein with agglutinating activity against strains of Streptococcus mutans.

A bacterial agglutinin specific for strains of Streptococcus mutans was isolated from human saliva. Physiochemical analyses showed the agglutinin to be a glycoprotein with a molecular weight of 60,000. The agglutinin aggregated four of the eight strains of Streptococcus mutans tested but did not aggregate the strains of Streptococcus salivarius, Streptococcus sanguis, and Streptococcus mitis tested. Chemical modification of carbohydrate moieties of the agglutinin with sodium metaperiodate had no effect on aggregation, whereas modification of the polypeptide portion with trypsin abolished aggregating activity. A set of five murine hybridoma antibodies was employed to further analyze the agglutinin. Two carbohydrate-specific antibodies, directed against D-mannose and N-acetylgalactosamine moieties, respectively, failed to block agglutinin- or whole saliva-mediated aggregation of S. mutans cells. In contrast, two antibodies directed against pronase-sensitive antigenic sites blocked both agglutinin- and saliva-mediated aggregation of S. mutans cells. Western blot analysis with the agglutinin-specific hybridoma antibodies demonstrated the agglutinin in whole saliva and in artificial tooth pellicles formed on hydroxyapatite beads incubated with saliva. These results suggest that a 60-kilodalton glycoprotein of human saliva is a bacterial agglutinin with specificity for certain strains of S. mutans. They further suggest that aggregation is mediated by polypeptide rather than carbohydrate determinants of the glycoprotein.

Agglutination↗
PubMed1990

Regulation of expression of Streptococcus mutans genes important to virulence.

Studies were initiated to investigate the regulation of Streptococcus mutans genes which are believed to be important to virulence. Operon fusions were constructed between S. mutans gene regulatory regions and a promoterless chloramphenicol acetyltransferase gene (cat) found on the plasmid pMH109. Specifically, fusions were generated between cat and the S. mutans genes encoding fructosyltransferase (ftf) and the glucosyltransferase B/C (gtfB/C) operon. Constructs were confirmed by restriction enzyme analysis, and the fusions were subcloned into the integration vehicle pVA891. Following generation of multimeric DNA, recombinant plasmids were introduced into the s. mutans genome by Campbell-type insertion, resulting in single-copy operon fusions. Chloramphenicol acetyltransferase specific activities were used to monitor the expression of the S. mutans gtfB/C operon and ftf determinants. The expression of these genes is increased by the presence of sucrose and is followed by a rapid decline in expression over time. Additionally, expression of the gtfB/C operon is increased in S. mutans cells bound to artificial tooth pellicles.

Chloramphenicol O-Acetyltransferase↗
PubMed1998

Periodontal ligament cell culture on the hydrophobic substrate coated with proteins of periodontal ligament fibroblast-conditioned medium.

In regenerating periodontal ligament (PDL) around the root of an artificial tooth, an important role is played by some physiologically active substance that promotes adhesion of the cells to the surface of the tooth root and induces cell proliferation and differentiation. In this study, the supernatant of the conditioned medium (CM) of dog periodontal ligament fibroblast (DPLF) was fractionated using an ion exchange chromatography-diethylaminoethyl (IEC-DEAE) column. DPLFs were cultured on hydrophobic dishes coated with each fraction. Cell proliferative activity and alkaline phosphatase (ALPase) activity, including electron microscopic features of the contact surface between the cells and the dish, were investigated. The DPLF-CM was separated by IEC-DEAE column into six fractions. Each fraction promoted an increase in DNA content and ALPase activity of the cultured DPLF, and especially remarkable were fractions 2 and 3. Fraction 2 at a molecular weight (Mw) of 210, 160, 85, 50 and 22 kD, and fraction 3 at Mw = 21 and 23 kD contained the type of proteins not found in other fractions. Electron microscopic analysis revealed that the cells in the coating group were in close contact with the surface of the dishes and that fine fibers protruding from the cell membrane clinged to the dishes. In the control group, a wide gap between the cells and the dishes was observed. These findings suggest that the DPLF-CM fractions contain specific physiological activating factors that induce proliferation and differentiation as well as cell adhesion of the DPLF cells.

Alkaline Phosphatase↗
PubMed1977

Direct bonding in the management of an ankylosed second deciduous molar.

A simple and efficient bonding procedure has been described for the management of an ankylosed deciduous second molar. This has, in our experience, provided a satisfactory occlusal and periodontal environment in selected patients. Based on a limited number of cases, restorations have been maintained for about two years to date.

Acrylic Resins↗
PubMed2006

Free-end space maintainers: design, utilization and advantages.

Primary molars are a determining factor in the development of occlusion. Given their importance, when restorative treatment is notfeasible and a primary molar must be extracted, the practitioner should keep in mind the risk of losing space, and the consequent malocclusion. Preservation of the space can eliminate or reduce the needforprolonged orthodontic treatment. For that reason, there are various kinds of space maintainers and the pediatric dentist must decide which one to utilize, on the basis of general and local factors related to the child In the selection of a treatment option for space maintenance, the greatest complications occur when the first permanent molar has not yet erupted A large variety of appliances have been devised to deal with this situation. This article proposes the use of a removable space maintainer that is open on one end and can be employed to guide the first permanent molar, maintaining the integrity of the mucous membrane and serving as a prosthetic appliance, preventing the complications and contraindications often caused by sub-gingival maintainers.

Child↗
PubMed1989

[Fundamental studies on bearing stress of basal seat under denture. 1. Difference height of ridge and load].

The purpose of this report is to investigate influence of difference in shape of ridge (height) and load (point, direction and strength) on bearing stress of basal seat. The stress against various loads (200-2,000 gf) onto artificial tooth (maxillaly first molar) were measured by using dentures, buried stress sensor, upon simulations of maxillaly edentulous posterior ridges with three types in height (9-15 mm). The summary of results are shown below: 1. When vertical loads onto mesial pit were applied, stress in working was most at ridge. The stronger load was, the more increased stress, and the shorter height of ridge was, the more decreased stress. Stress in balancing was most at palate. The stronger load was and the shorter height was, the more increased stress. 2. When oblique loads onto buccal cusp were applied 30 degrees to vertical, stress in working was most at palate. The stronger loads was, the more increased stress. In balancing, the stronger load was and the shorter height was, the more happened negative atmospheric pressure and breakaway of denture. 3. When oblique loads onto lingual cusp were applied 30 degrees to vertical, stress were most at buccal in working and at palate in balancing. At both areas, the stronger load was and the shorter height was, the more increased stress.

Alveolar Process↗
PubMed1993

Evaluation of damage to removable dentures in two cities in Finland.

The number of damaged dentures and type of damage to removable dentures repaired in dental laboratories was investigated using a questionnaire sent to 24 dental laboratories in Finland. Eight variables were examined for each damaged denture. The results showed that the type of dentures most commonly needing repair was the complete upper denture (49%). The most frequent type of damage was breakdown of the acrylic base and loosening of an artificial tooth. The chi-square test established a statistical dependence (p < 0.005) between damaged dentures and their age. Damaged upper partial dentures most frequently had natural teeth or fixed prostheses as antagonist teeth. Damaged lower skeletal dentures and acrylic partial dentures had a complete denture as the antagonist (p < 0.05). Removable dentures made of acrylic resin material seemed to break despite strengtheners, such as clasp wire.

Chi-Square Distribution↗
PubMed1990

[Statistical study of 41 cases with denture foreign bodies in the air and food passages and significance of the duplicated denture model].

A statistical study of 41 cases with denture foreign bodies in the air and upper food passages which were treated in our department during the past 21 years was done. (1) Males were more frequently affected. The ratio of male to female was about 2 to 1. (2) Of 41 dentures, 2, 2 and 37 were lodged in the air passages, hypopharynx and esophagus respectively. (3) There were 5 complete mandibular dentures in 41 cases. (4) The causes of the denture foreign bodies were originated to the problem of denture itself in 29 cases, that of the patient himself in 2 cases and both in 10 cases. (5) Of 39 problematic dentures, 16 showed the breakage such as plate fracture and clasp deformity, but the other 23 showed no breakage. In this latter group, poor holding of the denture was ascribed to miss-making or miss-planning. (6) Of 12 patients with problems in their physical function, 5 had suffered from cerebrovascular disease and 3 from geriatric dementia. (7) The denture foreign body in aged patients with physical hypofunction tends to increase in recent years. (8) Of 39 dentures tried to remove by esophagoscopy, 18 were done with difficulty and they were detachable partial dentures with one artificial tooth and 2-arm-clasps lodged at the first and/or second isthmus of the esophagus. Though we have a denture removed successfully at the third trial, we have no case needed external esophagotomy. (9) Duplicated denture models were made in 20 cases prior to the procedure, and we certify that these models play an important role for the safer removal of denture foreign bodies.

Adult↗
PubMed2005

Prosthodontic rehabilitation in Papillon-Lefevre syndrome: a case report.

Papillon-Lefevre syndrome is a rare recessive genetic disorder. The clinical manifestations include palmar-plantar hyperkeratosis with precocious rapidly progressive periodontal disease that results in premature exfoliation of primary and permanent dentitions. Patients are often edentulous at an early age. Here is the report of prosthodontic rehabilitation of a case of Papillon-Lefevre syndrome in a 6-year-old child.

Child↗
PubMedDate not supplied

Positioning implants for overdentures: a prototype implant-paralleling device. Technical note.

As implant-assisted dentistry continues to grow, increasing emphasis is being placed on the surgical positioning of implants so that they can be optimally restored. While this is essential for esthetics with fixed implant restorations, it is equally important with implant overdentures, where the type of retentive mechanism artificial tooth position, and denture flange contour may be affected by implant position Unfortunately, surgical guides or templates may be used less often with overdenture cases because of the associated time, costs, and difficulty in positioning during surgery, leading to compromised implant location or orientation. This paper describes a prototype paralleling device that can aid in the surgical positioning of implants for overdentures.

Dental Equipment↗
PubMed1998

[Electronic speckle pattern interferometric analysis on force distribution of different mandibular unilateral free-end dentures].

OBJECTIVE: To study the force distribution of three kinds of mandibular unilateral free-end partial denture under vertical loading on the artificial tooth. METHODS: A fresh mandible with right 2nd and 3rd molars missing was restored with cantilever fixed partial denture (CFD), casting three arm clasp removable partial denture (CCD) and RPI removable partial denture (RPID) respectively. The force distribution on the surface of supporting bone was studied by using electronic speckle pattern interferometry (ESPI). The ESIP was displayed real-time and recorded. The fringes determining was prossed by microcomputer image processing. The corresponding out of plane displacement of the supporting bone was measured and analyzed. RESULTS: Showed all of the three kinds of dentures contribute to transmit stress to supporting bone. The corresponding out of plane displacement of supporting bone decreased, the degree of decrease was CFD < CCD < RPID in order. CONCLUSION: This finding provides a useful reference for design of denture construction.

Adult↗
PubMed2004

Treatment selection for anterior endodontically involved teeth.

Innovations in material science and clinical techniques have expanded the number of treatment options available for nonvital anterior teeth. These options include the use of composite to fill the access opening with no additional treatment, crown placement, orthodontic extrusion, crown lengthening with or without orthodontic extrusion, dowel restorations with crown placement, and fixed bridge or implant therapy when extraction is necessary. Clinicians need to understand the benefits and limitations of each option in order to provide their patients with optimum function and aesthetics. Using case presentations, this article describes predictable approaches for the diagnosis, treatment planning, and restoration or replacement of endodontically treated teeth in the anterior region.

Adult↗