PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Denture Rebasing”

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.

584 records · Page 33Linked to original sources
PubMed2004

A subjective study of dimensional stability of permanent acrylic resin complete denture bases after a second curing cycle.

The aim of this study was to subjectively assess permanent denture base retention and stability in order to determine whether detrimental change occurred as a result of a second curing cycle. 100 complete upper denture bases were assessed by clinician and patient using visual analogue scales at try-in and insert. No statistically significant alteration in mean scores for retention and stability was seen. 5% of bases showed some deterioration, but none required rebasing or remaking as a result. The advantages of permanent bases during denture construction seem to outweigh the risk of loss of retention and/or stability as a result of distortion due to the second curing cycle.

Acrylic Resins↗
PubMed1990

[Stress breaking saddle framework or stress breaking framework. 1. Principles].

The treatment success of a removable partial denture is conditioned by the respect of the base structures, tooth abutments and hard and soft tissues. In order to achieve this goal, the prosthesis should be in accordance with the following fundamentals: tissue duality (STEIGER diagram); visco-elastic behaviour of the mucous membrane (TURK, KYDD, DALY, PICTON WILLS); JORES, LERICHE and POLICARD principles. The proposed prosthetic solution, the stress breaker framework allows the disconnexion between the saddle and the framework as well as between the different saddles. The originality of the concept is due to the particular design of the framework, which permits the disconnexion of the saddle. Due to its principle, the displacement of the saddle takes place only when mastication forces are applied on the prosthetic teeth. These movements stimulate the bony tissues. The clinical construction of a stress breaker framework can be adapted to all types of edentation, as well as to sub-total dentures. The clinical results shown that, after twelve years of experience, the stress breaker framework allows the preservation of the abutments as well as the conservation of osseo-mucous tissues (no need of rebase). Several experimental research investigations have been carried out. Work on trial banks have revealed that, compared with the semi-rigid framework, the stress breaker framework lays less stress on the abutment and provides a better base surface beneath the saddle. Other studies have dealt notably with the displacement of the saddle as well as with fatigue tests of the prosthetic system. These studies have led to the development of specific preformed systems.

Bite Force↗
PubMed1981

The effects of the incorporation of chlorhexidine acetate on some physical properties of polymerized and plasticized acrylics.

The effects on the water uptake and weight loss of the incorporation of chlorhexidine acetate in heat cured acrylic and an acrylic gel soft liner was determined. Hardness and transverse bend measurement were similarly made for admixtures to heat and cold cured acrylics. Following soaking in water for 87 days the heat cured test specimens demonstrated an initial weight gain followed by a progressive loss, the soft liner test specimens however all showed weight gains. Drying back specimens to constant weight revealed significantly greater weight losses in test compared to control specimens for both the cured acrylic and gel liner. However these weight losses were less than the chlorhexidine content for 5 and 10% admixtures. Hardness and moduli of elasticity measurements were significantly reduced for heat and cold cured acrylics containing chlorhexidine. The property changes observed in the materials would be consistent with the pattern of incorporation of chlorhexidine into the matrix. However, these do not negate the carriage of medicaments in these materials for prolonged delivery within the oral cavity, if employed as rebase or reline materials in existing prostheses.

Acrylates↗
PubMed1987

Evaluation of hard direct reline resins.

Peak curing temperatures of hard, direct, autopolymerizing reline resin materials tested were all within ADA specification guidelines. A temperature range of 10 degrees C was demonstrated among materials, with the highest polymerization temperatures recorded for Perm and Lang's Self-Curing Rebase Acrylic, and the lowest for KOOLiner, Flexacryl, and COE-Rect. This temperature difference is probably clinically detectable. However, intraoral testing of polymerization temperatures yielded lower peak values than those observed with specification testing, and the temperature peaks occurred earlier with intraoral conditions. There were significant color changes with simulated aging for three of the products tested: Flexacryl, COE-Rect, and Lang's Self-Curing Rebase Acrylic. The color changes occurred after only 24 hours of accelerated aging. Although there was only a small change in color with aging for Perm and KOOLiner, there was a moderate shift in the color of KOOLiner (delta E = 2.2) before aging. Thus only Perm demonstrated little color change with simulated aging. Of the reline products, one material, KOOLiner, demonstrated lower bond tensile strengths to denture base materials. However, the clinical significance of this was not known. One denture base material (Astron) recorded significantly higher bond strength values for all reline products and failure always took place within the denture base.

Chemical Phenomena↗
PubMed2000

Substitutes for methylene chloride as dental softening agent.

Methylene chloride is used as softening agent for guttapercha and as adhesion promotor for polymethylmethacrylate (PMMA). However, methylene chloride has been found to be carcinogenic. It was the aim of the present work to search for harmless substitutes for methylene chloride in these situations. A number of possible candidates with structural similarities to guttapercha or PMMA were selected. The efficacy in softening of guttapercha of these compounds was measured by the depth of penetration of a needle under the load of 2 N. The effect of the compounds on the adhesion between PMMA and an acrylic rebasing material was measured in shear. It was found that a number of alkenes or dialkenes of moderate molecular weight (1,3-pentadiene, cyclopentene, isoprene, 2-methyl-2-butene, and 1,5-hexadiene) were as effective as methylene chloride as softening agent for guttapercha. As adhesion promotor in bonding to PMMA, it was found that low molecular weight methyl esters (methyl formate and methyl acetate) were as effective as methylene chloride. Because of the variation in polarity, the calculated solubility parameter was not a reliable predictor of softening efficacy of the investigated compounds.

Acetates↗
PubMed1989

[ESR study on self-curing resin for rebasing during polymerization].

The effects of temperature, concentrations of activator (N, N-dimethyl-p-toluidine) and inhibitor (hydroquinone), atmosphere, liquid powder ratio and mixing time on polymerization process of self-curing resin for rebasing were studied by electron spin resonance. When powder and liquid were mixed at a ratio commercially recommended at a physiologic temperature of 37 degrees C, the propagating radical was first detected 5.5 minutes later, of which time interval corresponds to induction time for polymerization. After the induction time, the concentration of propagating radicals increased rapidly with time and reached the maximum level at 27 minutes. The radicals thus formed remained stable for more than 2.5 days when stored in air at 37 degrees C, though their concentration diminished gradually. With increasing temperature for curing, the maximum level of the radical concentration decreased and the propagating radicals disappeared more rapidly, indicating recombination reactions to be perferentially occurring at higher temperatures. Increase in the amount of activator of N,N-dimethyl-p-toluidine resulted in increase in the radical concentration. When powder was mixed with a liquid containing less inhibitor of hydroquinone, the radicals were found to remain stable longer. In air, propagating radical was detected faster and free radical was concentrated more rapidly than in the water and nitrogen gas. The fluidity of self-cured resin for rebasing as measured by use of spin probe TEMPO disappeared rapidly with increasing temperature for curing, decreasing the amount of liquid and shortening the mixing time. When curing temperature was raised to 37 degrees C from 22 degrees C at minutes after mixing, the fluidity disappeared 2.5 minutes later, i.e., at 5.5 minutes after mixing. To investigate the effects of the MMA-derivative radicals on growth of HeLa cells, HeLa cells were cultured on resins containing MMA-derivative radicals. The number of HeLa cells on resins containing MMA-derivative radicals was 7/10 of that of HeLa cells on resins containing no radicals.

Denture Bases↗
PubMed1990

[Supplemental studies on self-curing resins. 2. On polymerizing temperature of reline materials].

The objective of this study was to find the best way to keep down the peak temperature of self-curing reline materials. The experiments were done by using three kinds of self-curing reline materials (Rebaron, REBASE and KOOLiner) and three kinds of the reline materials of different thickness (1.5mm, 2mm and 3mm) under three different intraoral conditions. When these reline materials cured under rinsing the mouth with cold water (18 degrees C), the data analysis of these reline materials showed a considerable reduction in the peak curing temperatures clinical acceptance. The results obtained were as follows: 1. Both extraoral and interoral curing tests showed that the thicker the material is the higher the peak temperature becomes. 2. Highly significant differences in time to the peak temperature were found among the three kinds of reline materials. 3. Dangerously high temperature was found in polymerizing of the thickest material, 3mm.

Denture Liners↗