PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 2489771

[Structural designs in the removable partial dentures].

C Ohkubo
View original source ↗Export metadata ↓

Abstract

Today the removable partial dentures are used as permanent prosthetic devices. Thus, their designs must be considered the prevention of breakage or deformation. A metal plate denture consisting of double structure has been designed with the intention of improved mechanical strength and durability. Principal investigations of this study were to introduce structural design techniques and apply them to denture design, to analyze the double structure using the finite element method, to judge reliability using a statical bending test, to compare the breaking strength of each structure, and to measure movement during function of mandibular extension base removable partial dentures on the simulation model. The summary of results is shown below: 1. Calculated values and experimental values were a fairly good approximation. 2. The reinforcement and Lightweight method of double structure was made evident. 3. Regarding the packing resins, METADENT was slightly superior in mechanical strength to ACRON. 4. Maximum stiffness of the double structure was approximately 7-10 times that of skeleton types, and breaking strength was about 9 times. 5. Tensile strain generated at the double structure was statistical less than for skeleton types. 6. When loads of 10 kg applied, the difference of distal displacement between double structure and skeleton types was between 70-80 microns. 7. The stiffness of the skeleton types decreased remarkably by shortening the denture flanges, but the double structure did not show significant change.

Explore related subjects

Dental Stress AnalysisDenture DesignDenture, Partial, RemovableElasticityTensile StrengthEnglish AbstractJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

C Ohkubo. 1989. [Structural designs in the removable partial dentures].. https://doi.org/10.2186/jjps.33.1273

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed1996

Frictional resistances in stainless steel bracket-wire combinations with effects of vertical deflections.

This research evaluated the effects of different bracket-wire combinations and second-order deflections on kinetic friction. Thirteen different brackets, six with 0.018 x 0.025 inch slots and seven with 0.022 x 0.028-inch slots were evaluated with six different sizes and shapes of stainless steel orthodontic wire, i.e., 0.016, 0.016 x 0.022, 0.017 x 0.025, 0.018, 0.018 x 0.025 and 0.019 x 0.026 inch for four second order deflections of 0.00, 0.25, 0.50, and 0.75 mm. The wires were ligated into the brackets with elastomeric modules. Bracket movement was implemented by means of an Instron universal testing instrument (RMO, Denver, Colo.), and frictional forces were measured by a tension load cell and recorded on an X-Y recorder (Hewlett-Packard, Anaheim, Calif.). Second-order deflection was created by a specially designed and machined testing apparatus that allowed two alternate pairs of the four total brackets to be offset in increments of 0.25 mm. The kinetic frictional force increased for every bracket-wire combination tested as the second-order deflection increased. Friction also increased with an increase in wire size, whereas rectangular wires produced greater friction than round wires. Bracket designs that limited the force of ligation on the wire generated less friction at low second-order deflections (0.00 and 0.25 mm).

Dental Stress Analysis↗
PubMed1995

[The force level of pseudoelastic leveling wires in relation to interbracket distance].

One of the arguments for the introduction of pseudo-elastic wire materials was "the way they work biologically", that is to say, on the one hand small and uniform force over an extended period of time and on the other the avoidance of excessive forces during the leveling phase. Since an evaluation of the operative force of such an arch wire is dependent on temperature, stress-strain curve, and method of activation, and because the extent of the activation is no longer directly proportional to the operative force, the result is that it is often difficult to determine clinically, whether a safe maximum force is not being exceeded. To clarify this issue arch wires were tested in a three bracket test simulating to the greatest degree possible a clinical situation. The inter-bracket distance was selected in accordance with the situation in the upper and lower incisor region independent of the width of the bracket. The results showed rather high forces for some of the wires. Often these forces were higher in the mandibular situation due to non-ideal force deflection curves than in the supramaxilla. One of the tested materials did, however, effectively limit the operative force in the upper and lower jaw. Especially significant is that the differing characteristics of the tested wire materials result in a completely different action in relation to force development.

Dental Stress Analysis↗
PubMed1995

Rationale of the segmented approach to orthodontic treatment.

Modern orthodontics requires defined treatment goals. To achieve them, known force systems must be used to control the active units (teeth being moved) and the reactive units (anchorage teeth). This article discusses the methods of controlling the force systems through the variables of spring design and anchorage selection. Continuous and segmented arch treatment are contrasted in their ability to achieve optimal and defined force systems with minimal side effects.

Dental Stress Analysis↗