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At least 199 records · Page 11Linked to original sources
PubMed1989

[Adaptation of acrylic resin dentures polymerized using various activation modes].

The purpose of this in vitro study was to compare the dimensional accuracy of maxillary dentures made using a conventional heat-activated PMMA resin, a pour resin, a visible light-activated resin, and a microwave-activated acrylic resin. Two simple methods for measuring dimensional accuracy were used: (1) weight of impression material entrapped between the base and master die and (2) measurement of the posterior border gap at five locations. The volume of space between the denture base and the master die was determined by (1) computation and (2) estimation. Statistical analysis (Bartlett, ANOVA and Tukey's Tests) supported the following conclusions: (1) all groups showed a processing contraction, most apparent from buccal flange to buccal flange, (2) the poorest fitting group was processed in a brass flask and a water bath at a temperature which rose from 70 to 100 degrees C, using a heat activated resin (Acron), (3) the visible light activated resin (Triad) produced dentures of intermediate accuracy, as did Acupac 20 when either heat or microwave activated, (4) the two best fitting groups were prepared from a chemically activated resin system using pressure at low heat (PER form), and the resin developed for microwave activation (Acron MC).

Acrylic Resins↗
PubMedDate not supplied

Reinforcing effect of a Ni-Cr alloy plate on an acrylic resin denture base.

The authors previously reported on the strengthening effect of a thin Ni-Cr plate on an acrylic resin test specimen in the three-point bending test. This study evaluated the reinforcement of acrylic resin denture bases by measuring the strain distribution in the palate of a maxillary complete denture. It was found that this reinforcing technique led to a uniform distribution of strain in the palatal area of the maxillary denture and a reduction of strain in the midpalatal area.

Acrylic Resins↗
PubMedDate not supplied

The in vitro color stability of acrylic resins for provisional restorations.

This study made an in vitro comparative evaluation of the color variation of four types of acrylic resin for provisional fixed prostheses, as determined using computerized spectrophotometry, before and after a 20- and 30-day cycle of immersion in four staining solutions. The four acrylic resins used for provisional fixed restorations were: Cold Pac, Trim, Protemp, and Mixacryl II. Thirty-two specimens for each resin were divided into four subgroups of eight elements, immersed in the four staining solutions (synthetic saliva, synthetic saliva and tea, synthetic saliva and coffee, and synthetic saliva and chlorhexidine in 0.12% water solution), and then placed into four thermostatic baths at 37 degrees C +/- 1 degree C. All specimens were measured for each resin before immersion (baseline). After 20 and 30 days, the specimens were analyzed by computerized spectrophotometry and compared. All data were analyzed with analysis of variance for repeated measures (P < .05). Only the Cold Pac resin was color stable in all staining solutions, while the others showed color changes from the different staining solutions.

Acrylic Resins↗
PubMed1990

Use of the acid-etch technique to maintain antimicrobial-containing acrylic resin strips in situ.

A technique that utilizes acid-etched composite resin to maintain antimicrobial-containing acrylic resin strips in situ is described. The advantage of this technique is that placement of a periodontal pack is unnecessary, so control of supragingival plaque is not hindered at the site of the local antimicrobial delivery. The technique described may improve the effectiveness and the clinical acceptability of local antimicrobials in the treatment of periodontal disease.

Acid Etching, Dental↗
PubMed1997

Assessment of the acrylic resin Technovit 7200 VLC for studying the gingival mucosa by light and electron microscopy.

Technovit 7200 VLC is an acrylic resin formulated for embedding undecalcified hard tissues which are prepared for light microscopy according to a cutting-grinding technique. To employ this resin for embedding and cutting soft tissues by ultramicrotomy, we carried out a qualitative study on biopsies of canine gingival mucosa using light and transmission electron microscopy. For a critical evaluation of this resin, some biopsies were embedded in Agar 100, an epoxy resin widely used in morphological studies. At the light microscopic level the samples embedded in Technovit 7200 VLC showed good morphology and excellent toluidine blue staining of different cell types and extra cellular matrix. At the ultrastructural level, nuclei, cytoplasmic organelles, collagen fibrils and ground substance appeared well preserved and showed high electron density. The acrylic resin was stable under the electron beam and its degree of shrinkage appeared to be very low. We conclude that Technovit 7200 VLC can be employed for ultramicrotomy for both light and electron microscopic investigation of soft tissues.

Acrylic Resins↗
PubMed1977

A simplified acrylic resin cast technique.

A simple technique for construction of acrylic resin casts has been described. This procedure utilizes inexpensive and standard supplies found in a dental office.

Acrylic Resins↗
PubMed1998

Linear dimensional change of heat-cured acrylic resin complete dentures after reline and rebase.

STATEMENT OF PROBLEM: Relining and rebasing of complete dentures are common procedures to improve the fit of the prostheses. After relining or rebasing, adjustments may be required because of dimensional change that occurs during reprocessing of the denture when new denture base material is polymerized. PURPOSE: This study analyzed the linear dimensional change of heat cured acrylic resin that occurs during reline and rebase procedures for complete dentures. MATERIAL AND METHODS: Twenty-two maxillary and mandibular complete denture bases with artificial teeth were saturated by immersion in distilled water at 37 degrees C +/- 1 degree C. Fine crosses were marked on the incisal edges of the central incisors and the supporting cusps of the second molar teeth. Distances between the marks were measured with a high resolution traveling microscope. Heat-cured acrylic resin was processed by a long curing cycle of 72 degrees C for 6.5 hours, then heated to 100 degrees C for over 30 minutes and kept at 100 degrees C for 1 hour. The relined or rebased denture was allowed to cool slowly in the water bath for 48 hours to reach ambient temperature. The reference-crosses were measured immediately after careful deflasking. RESULTS: In the relining procedure, all incisor-molar and intermolar distances exhibited shrinkage of 0.3%, despite different shapes of maxillary and mandibular dentures. Results of the rebasing procedure were similar to that of the reline expect that only 0.1% intermolar shrinkage was found on the maxillary denture. CONCLUSION: Shrinkage was approximately 0.15 mm for an interarch distance of 50 mm. This degree of change is both clinically undetectable and insignificant. Using this processing cycle for acrylic resin in reline or rebase procedures did not cause clinically significant dimensional changes to complete dentures.

Acrylic Resins↗
PubMed1986

[Reconstruction methods of anterior chest wall resection--comparison between acrylic resins and myocutaneous flaps].

A total of 32 patients were treated by chest wall resection for primary and recurrent breast cancer or other malignant tumors of the chest wall. Reconstruction of the anterior chest wall was conducted using either acrylic resin plate or myocutaneous flap. Although acrylic resin plate proved to be satisfactory for maintaining stability of the chest wall and protecting important organs in the anterior mediastinum, some patients developed foreign body reactions including local infections, local retention of serous discharge and slight anterior chest pain during a prolonged observation. Reconstruction with myocutaneous flap achieved acceptable stability and caused no such foreign body reactions. We confirmed that myocutaneous flap was the best way to reconstruct the anterior chest wall after full thickness chest wall resection.

Acrylic Resins↗
PubMed1998

Repair of acrylic resin denture base reinforced with glass fiber.

STATEMENT OF PROBLEM: The ultimate goal of any denture repair is to restore the original strength of the denture and to avoid further fracture. PURPOSE: This study investigated the strength and deflection of repaired acrylic resin joints reinforced with various glass fiber concentrations. MATERIAL AND METHODS: Transverse strength, maximum deflection, and modulus of elasticity of glass fiber-reinforced polymethyl methacrylate acrylic resin were studied with a 3-point load test on 54 intact specimens. Six concentrations of type B glass fiber specimens were prepared (n = 9 per each fiber group). Fractured joint margins were rounded, a 2-mm gap was placed between them, and then they were repaired with autopolymerizing acrylic resin and retested. RESULTS: Transverse strength, maximum deflection, and the stiffness of all joints were significantly lower after the repair. Among the groups tested, the units treated with 1% glass fiber displayed the highest transverse strength before and after repair. Modulus of elasticity of the repaired 1% fiber concentration units was enhanced by approximately 25% over those repaired but untreated with glass fiber (0% fiber).

Analysis of Variance↗
PubMed1992

A shade guide for acrylic resin facial prostheses.

The value and success of a well-fitting and anatomically correct prosthesis are compromised if the color does not match the adjoining tissue. Color and color science are reviewed to help develop a simplified acrylic resin shade guide to aid in fabricating acrylic resin facial prostheses. This guide will help the clinician obtain a good intrinsic shade and minimize extrinsic coloration.

Acrylic Resins↗
PubMed1993

Technique for controlling the thickness of a facial prosthesis when an acrylic resin core is used.

A technique for evaluating the acrylic resin core before processing a silicone facial prosthesis is described. The technique involves the use of either irreversible hydrocolloid impression material or silicone to identify thin areas in the pattern. This simple yet effective procedure ensures adequate thickness and strength of the silicone prosthesis, which in turn decreases the amount of chair and laboratory time needed at the delivery appointment.

Acrylic Resins↗
PubMedDate not supplied

[Quantitative evaluation of reflectance of some acrylic resins mixed with powdered enamel and/or natural quartz].

Autopolymerizing acrylic resins for temporary prothesis and crown veneering have been mixed with dental enamel and/or quartz in powder form in different percentages, to simulate optical properties of the tooth. The analysis of our measurements of apparent reflectance of those mixings show that is possible to approximate several of those values to the ones corresponding to natural tooth; being sufficient to follow the formulation given++ in this paper.

Acrylic Resins↗
PubMed1980

Bond strength of bimaterial acrylic resin combinations.

While further research is necessary on the subject of the strength and nature of the bond between different types of acrylic resins, our study shows that specimens fabricated from heat-accelerated BPM showed considerably higher transverse strength values when compared with the various bimaterial combinations. From this, and from the fact that all bimaterial combinations broke at the joining interface, it can be inferred that none of the acrylic resin bimaterial combinations developed a true "chemical bond."

Acrylic Resins↗