PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “ACRYLIC RESINS”

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 217 records · Page 12Linked to original sources
PubMed2000

Differential scanning calorimetric study of acrylic resin powders used in dentistry.

The thermal behavior of eight dental acrylic resin powders was studied using differential scanning calorimetry (DSC). In addition, high performance liquid chromatography was performed to supplement the DSC analysis. The HPLC analysis revealed that the contents of residual monomers and benzoyl peroxide (BPO) in the powders were 0.01-0.97 mass% and 0.25-1.28 mass%, respectively. All the resin powders produced one broad exothermic peak, while a mixture of BPO and PMMA powders generated two peaks. One peak pattern was assigned to the decomposition of BPO included within the polymer particles. The results suggested that BPO was present inside the particles and little BPO was mixed into the resin powders. Moreover, the present study demonstrated a unique useability of DSC in characterizing resin powders.

Acrylic Resins↗
PubMed2005

Patients' preference for acrylic resin major connector analogues formulated for titanium alloy removable partial dentures.

PURPOSE: Aim of this study was to determine patients' preference to acrylic resin major connector analogues (MCA) that simulated strengthened major connector designs formulated for Ti-6Al-7Nb alloy. MATERIALS AND METHODS: Four MCA namely wide design (Wide), design with 2 strengthening ridges (2SR), design with 1 strengthening ridge (1SR), and thick design (Thick) were fabricated using light-polymerizing acrylic resin for 10 patients with Kennedy Class I or II partially edentulous maxillary arches. They were asked to wear each MCA in the mouth for 30 seconds in 6 pairs, and to report their preference for each pair. Using these data the 4 MCA were ranked in a descending preference order for each patient. A within-subject comparison of preferences was performed with the Friedman test and multiple comparisons with Wilcoxon Signed Ranks test. RESULTS: A statistically significant preference order was revealed: Wide, 1SR, 2SR, and Thick (P < 0.008). The wide design (P < 0.004) and the 1SR (P < 0.01) were significantly preferred to the thick design. However, individual data showed that the first preference varied depending upon the subject. CONCLUSION: Thinner designs tended to be preferred to the thicker design by the subjects, while none of the designs tested were consistently selected as the best design.

Acrylic Resins↗
PubMed2002

Reinforcement of acrylic resins for provisional fixed restorations. Part III: effects of addition of titania and zirconia mixtures on some mechanical and physical properties.

Acrylic resins have been used in many different applications in dentistry, especially in the fabrication of provisional fixed partial dentures. Ideally, a provisional crown and bridge material should be easy to handle and should protect teeth against physical, chemical, and thermal injuries. Some of the problems associated with this use are related to the material's poor mechanical properties. It has been demonstrated that acrylic resin can be strengthened through the addition of structural component of different size distributed in the acrylic matrix, thus forming a composite structure. The purpose of this study was to investigate the addition effects of mixtures of titania (titanium dioxide, TiO(2)) powder and zirconia (zirconium dioxide, ZrO(2)) powder being incorporated with pre-polymerized beads mixed in monomer liquid, on some mechanical and physical properties of PMMA resin. The pre-polymerized powder poly(methyl methacrylate) resin was admixed with titania and zirconia powder. A mixing ratio was controlled by volume % of 0, 1.0, 2.0, and 3.0 (samples with 0 v/o served as control groups). For using mixture of titania and zirconia, total amount of the mixture was controlled by volume % of 1.0, 2.0, and 3.0, in which titania and zirconia were mixed at the ratio 1 :1, 1 :2 and 2 :1. Prior to mechanical tests, all rectangular-shaped samples (25 mm x 2 mm x 5 mm) were stored in 37 degrees C distilled water for 7 days after polishing all six sides of samples. Samples were then subjected to the three-point bending flexion test to evaluate the bending strength as well as the modulus of elasticity. Weight gain and exothermic reaction survey were investigated as well. All data were collected and analyzed with one-way analysis of variance (ANOVA) and Sidak method (p=0.05). It was found that the addition of particles generally decreased the water absorbed by the composite system. Only 1 percent by volume concentration of 1 :1 ratio and 2 percent by volume concentration of 1 :2 and 2 :1 ratios had significantly higher strength than control group. There was significantly higher toughness (in terms of energy-to-break) for 1 percent by volume concentration of 1 :1 ratio and 2 percent by volume concentration of 2 :1 ratio than control group. There was no significant difference between control group and all percent by volume combinations in modulus of elasticity. In addition, there was no significant variations of exothermic reaction.

Absorption↗
PubMed1995

[The evaluation of acrylic resins for the study of nondecalcified human teeth with the light and electronic microscopes].

Resin embedding of human teeth for light and transmission electron microscopic studies becomes difficult without previous decalcification. The limited and slow infiltration of the resin into hard tissues may cause problems during preparation and observation of the samples. Moreover the type of resin that is used may affect the morphologic preservation of both tissues and cellular elements. Recently there has been an increasing number of studies on the application of acrylic resins in light and electron microscopy, in order to overcome problems encountered with the use of epoxy resins still utilized in morphologic studies. We compared different acrylic resins (Technovit 7200 VLC, LR White, LR Gold, Bioacryl) in order to understand which one was more suitable for undecalcified human dental tissues under light and transmission electron microscope. Evaluation of such resins was performed using the following criteria: ease of cutting with ultramicrotome, soft and hard tissues infiltration, uptake of tissue stains for both light and electron microscopy, morphologic preservation and stability under electron beam. This study, carried out on the pulp area comprising predentin and dentin, showed excellent quality of Bioacryl and LR Gold, the two resins presenting, by far, the best results among all the different types tested. The optimal morphologic preservation obtained with such resins is indicated for light and electron microscopic studies, allowing their application in different fields of dental research.

Acrylic Resins↗
PubMed1993

Effect of an ultraviolet light-activated coating material on reduction of the leaching of methyl methacrylate and formaldehyde from denture acrylic resins.

Effect of glazing with an ultraviolet light-activated coating material on reduction of the leaching of methyl methacrylate and formaldehyde from denture acrylic resins was quantitatively evaluated. Disks prepared from auto-polymerized resins were painted with the material and radiated with ultraviolet light. The disks were immersed in artificial saliva and the concentrations of methyl methacrylate and formaldehyde leached were determined by high-performance liquid chromatography and flow injection analysis. Compared to untreated controls, the glaze significantly decreased concentrations of both leachable substances. Treatment with an ultraviolet light-activated coating material is effective in suppressing the leaching of methyl methacrylate and formaldehyde from acrylic resins as well as in smoothing the denture surfaces.

Acrylic Resins↗
PubMedDate not supplied

The effect of different polishing techniques on the surface roughness of acrylic resin materials.

This study evaluated three methods of surface polishing on acrylic denture base materials. Specimens of three commercial heat-cured acrylic resin materials were finished using burs, sandpaper discs and rubber wheels, and polished with polishing soap, paste, or by application of a UV-light-activated resin sealant. The resulting surface roughness was examined by scanning electron microscopy as well as measured by means of a stylus profile Perthometer. Surface roughness was reduced by polishing. Polishing paste and UV-light-activated resin sealant were more, and equally, effective in reducing surface roughness compared to polishing soap. Polishing paste or UV-light-activated resin sealant may be used to create a smoother surface on acrylic dentures.

Acrylic Resins↗
PubMedDate not supplied

Reconstruction of the chest wall after full thickness resection: a comparison between myocutaneous flap and acrylic resin plate as reconstructive techniques.

Thirty-three patients with chest wall malignancies underwent full thickness resection of the chest wall and immediate reconstruction of the defects with either synthetic materials (acrylic resin plate, 16 patients) or with myocutaneous flaps (rectus abdominis flaps, 17 patients). Although the acrylic resin plate proved to be excellent for maintaining stability of the chest wall, five patients suffered from local skin necrosis, requiring skin grafting, and four suffered from persistent foreign body reactions, necessitating ultimate removal of the plate. The patients receiving myocutaneous flap repair had excellent wound healing, acceptable rigidity of their chest wall, and no foreign body reactions throughout the follow-up period. The 50% post-operative survival time for the entire series was 29 months, suggesting that the procedure in an effective treatment modality for breast cancer involving the chest wall. Reconstruction with a myocutaneous flap is indicated as long as the chest wall defect is not too extensive.

Acrylic Resins↗
PubMed1990

In vitro study on the inhibiting effect of different agents on the growth of Candida albicans on acrylic resin surfaces.

This study evaluated at the in vitro level the antifungal effectiveness of nystatin, chlorhexidine, and a homologous histidine polypeptide on the surface of acrylic resin disks. The agents were used in a way that simulated storage of a denture by a denture wearer. Results indicated that pretreatment with poly-L-histidine was not protective against C albicans adherence and growth regardless of whether disks were stored in water or in the open air for the 8-hour period following yeast contamination. Chlorhexidine was totally effective in preventing C albicans attachment to, and growth on, the acrylic resin, even after a period of 8 days of turbidimetric monitoring. Pretreatment with Nystatin, followed by drying, was protective, yielding results similar to those obtained with chlorhexidine.

Acrylic Resins↗
PubMedDate not supplied

Clinical survey of acrylic resin removable denture repairs with glass-fiber reinforcement.

PURPOSE: The aim of this study was to evaluate clinical usefulness and durability of continuous glass-fiber reinforcement in repair of acrylic resin removable dentures. MATERIALS AND METHODS: Fractured removable dentures without reinforcement, with conventional metal-wire reinforcement, or with mesh reinforcement were collected from two dental schools in Finland. The total number of dentures was 51 and the number of patients was 48. During the repair, the dentures were reinforced with a polymer-preimpregnated E-glass fiber at the region of the fracture. The fibers were used as partial fiber reinforcement, i.e., only the weakest part of the denture was reinforced. Follow-up time varied from 4 months to 4.1 years. After the follow-up period, possible fractures and discoloring were visually inspected. Possible irritation of oral mucosa by glass fibers and the general shape of the denture were also evaluated. RESULTS: In 88% of the cases, there was no need for adjustment at the region of partial fiber reinforcement, and the clinical condition of the dentures was good. Glass fibers did not irritate the oral mucosa. In the case of refracture or hairline fracture, positioning of the partial fiber reinforcement was incorrect or the reinforcement had been used incorrectly (the wetting of the reinforcement with denture base resin was inadequate). CONCLUSION: Polymer-preimpregnated partial fiber reinforcement seems to be useful in eliminating fractures of acrylic resin removable dentures. However, this study emphasizes the importance of correct positioning and accurate laboratory technique when partial fiber reinforcement is used.

Acrylic Resins↗
PubMed1999

Achieving an even thickness in heat-polymerized permanent acrylic resin denture bases for complete dentures.

Permanent denture bases form the fitting surface of a denture and are constructed on a master cast, in heat-polymerized acrylic resin. These bases are strong and rigid and demonstrate both the fit and retention of the final prosthesis. General recommendations suggests a thickness of between 1.5 to 3 mm for these bases. The normal procedure for producing such a denture base is to manually adapt materials to the cast, in their plastic state, before processing. Such procedures are liable to distortion and variation in the thickness of the resultant denture base and may be unreliable. This article describes a method for achieving a consistent thickness in a heat-polymerized, permanent, acrylic resin denture base through the use of a vacuum-formed, thermoplastic blank as a template. The method is simple, and results in a denture base with a consistent even thickness.

Acrylic Resins↗
PubMed1986

Dimensional stability of autopolymerizing acrylic resin impression trays.

A study was undertaken to determine the optimal interval between fabrication of an autopolymerizing acrylic resin custom impression tray and making a final impression. Twenty mandibular arch-shaped trays, 10 each of Fastray and Formatray resin, were evaluated for dimensional change. Both materials behaved similarly. Cross-arch contraction of the borders of buccal flanges and unilateral expansion of the borders of buccal-to-lingual flanges were observed. These changes indicate distortion. Linear dimensional changes occurred throughout 6 hours, which suggests that any impression made in a methyl methacrylate acrylic resin custom impression tray should be poured as soon as is conveniently possible. Significant linear dimensional changes were observed for only 40 minutes from the initiation of tray fabrication. This study concludes that while an aged tray is preferred, it is acceptable to make an impression in an autopolymerizing resin custom impression tray after 40 minutes.

Chemical Phenomena↗
PubMed1995

Reinforcement of denture acrylic resin: the effect of metal inserts and denture resin type on fracture resistance.

This study investigated the fracture load and deflection of acrylic resin specimens with different types of metal inserts. A metal adhesive denture resin (Meta Dent) and a conventional denture resin (Meliodent) were used with round metal, braided wires and mesh as inserts. There were eight groups and each group contained ten specimens. Each specimen was broken on a Monsanto testing machine using a three point load after storage in water at 37 degrees C for 48 hours. The results indicated that metal inserts enhanced the fracture resistance of both denture resins. No significant differences were found between the metal adhesive and conventional denture resin.

Acrylic Resins↗
PubMed1983

The abrasion of acrylic resin by cleaning pastes.

The physical removal of plaque from dentures by brushing is important in the maintenance of oral health. However, there is a danger that brushing will abrade acrylic resin. A machine using a rotary brushing action was therefore utilized for laboratory tests of possible cleaning pastes, employing a toothbrush with good access and adaptability to denture surfaces. Crest toothpaste produced the most abrasion on acrylic resin, Dentu-Creme the least. An experimental paste produced an appreciably lower abrasion rate. Self-cured specimens wore more than heat-cured ones. The rate of abrasion decreased as the temperature was raised. Brushing with water alone, or with a 10% solution of soap, did not produce detectable wear. The wear produced by proprietary cleaners when hand brushing the lingual flanges of dentures and flat blanks of heat-cured acrylic was also measured. Boots denture cleaning paste produced the greatest abrasion, Dentu-Creme the least. The wear measured by reference to a glass plane was at least twice that recorded by the decrease in depth of a groove. The machine did not quantitatively produce the same abrasion as hand brushing, nor did it qualitatively rank the pastes in the same order of abrasiveness. The clinical relevance of these results is discussed.

Acrylic Resins↗
PubMedDate not supplied

A study of acrylic resin denture base material distortion using computer-aided holographic interferometry.

A holographic interferometer for investigating deformations of dental prostheses is described. Residual stress relaxation resulting from the polymerization of acrylic resin dentures is qualitatively studied during the first 48 hours following fabrication. The resulting fringe patterns show a symmetry that is correlated to the shape of the denture. A quantitative analysis of the interferograms was performed with the aid of a computer program. The computer-aided holographic interferometer was tested using disk-shaped acrylic resin materials. Dimensional deformations resulting from temperature changes were measured with an accuracy better than 0.2 microns. Because of the aging of the resin material, the reaction to temperature changes may differ as a function of time and may be studied using quantitative comparison of deformation plots. For convenience, the original object shape can be added to or subtracted from the graphical deformation data.

Acrylic Resins↗
PubMed1996

Craniofacial osseointegration: technique for bar and acrylic resin substructure construction for auricular prostheses.

Retention of auricular prostheses with adhesives is frequently problematic. Craniofacial osseointegrated implants have become an accepted biotechnique used in auricular reconstruction. This article describes a procedure for bar and acrylic resin substructure construction that allows for the incorporation of desired features. The most common means of retaining auricular prostheses is with bar and clip systems. For auricular prostheses, two implants are placed with the bar designed to minimize torquing on the implants and to facilitate hygiene. Additionally, the bar should not have to be removed from the patient when new prostheses are to be constructed. The procedure provides for a more biomechanically effective bar construction and efficient means of constructing replicate acrylic resin substructures.

Acrylic Resins↗