PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “DENTAL IMPRESSION MATERIALS”

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 253 records · Page 14Linked to original sources
PubMed1995

Dual-tray impression technique for implant-retained overdentures.

Accurately recording implant positions and the edentulous areas during the fabrication of implant-retained overdentures can be a difficult task. A modification of the dual or split-tray technique is suggested for implant-retained overdentures. This procedure permits the construction of the prosthesis on one master cast and the use of two impression materials with different properties incorporated into a single impression to correspond with the needs of specific anatomic areas of the mouth.

Dental Casting Technique↗
PubMed2003

A retrospective comparison of two definitive impression techniques and their associated postinsertion adjustments in complete denture prosthodontics.

PURPOSE: To compare the number of postinsertion adjustment visits required by edentulous patients whose dentures were made from border-molded definitive impressions using modeling plastic impression compound (traditional technique) with patients whose dentures were made from border-molded definitive impressions using heavy-body vinyl polysiloxane impression material. MATERIALS AND METHODS: In this retrospective clinical study, 78 patients were treated with the traditional technique (custom impression trays border molded with gray modeling plastic impression compound) and 78 were treated with the modified technique (custom impression trays border molded with heavy-body vinyl polysiloxane impression material). In both techniques, definitive wash impressions were made with light-body vinyl polysiloxane impression material. Postinsertion visits were quantified for 1 year after the dentures were inserted. RESULTS: The average number of adjustment visits for patients treated with the traditional technique was 2.68. The average number of adjustment visits for patients treated with the modified technique was 2.68. The data were compared using Student t tests. There was no significant difference in the number of adjustments required for patients whose dentures were made with either technique (t = 0.000, p = 1.00). There was no significant difference in the number of post-insertion visits required by patients from either population. CONCLUSIONS: Within the limitations of this clinical study, border-molding custom denture impression trays with vinyl polysiloxane impression material provided similar results in terms of postinsertion visits for one year as compared to dentures made from impressions border molded with modeling plastic impression compound.

Appointments and Schedules↗
PubMedDate not supplied

Requirements of an impression material for fixed prostheses.

This article reviews the clinical and laboratory steps in taking impressions for creating fixed prostheses. Recommendations for selecting impression materials and techniques for using them are discussed. Common problems associated with impressions, and their possible causes, are also included.

Crowns↗
PubMed1992

[Studies on dimensional accuracy of working casts made by various impression techniques--influence of undercuts on dimensional accuracy].

The purpose of this research was to evaluate the clinical acceptability of various impression techniques by comparing the dimensional accuracy of their working casts. An original metallic model was designed for this experiment. It has reference points to overlap and compare the master model and the working casts for measuring their dimensional accuracy under the same condition. The amount of distortion in each area of the working casts was examined by the measuring points within the model. The master model simulated an abutment for a full veneer crown with undercuts between the adjacent teeth. It was planned so that the amount of undercuts and distances between the adjacent teeth could be changed. As a result, a small distortion of the working casts due to the undercuts was observed by the technique using an individual tooth tray and polysulfide rubber base impression material. There was no significant dimensional change in the working casts made with silicone rubber base material. For the working casts made by hydrocolloid-alginate combination technique, the dimensional change was greater and distortion was observed in the abutment cast when the undercuts of the adjacent teeth were great. However, the distortion was less when the undercuts were small.

Dental Casting Technique↗
PubMed2002

Relining extension-base removable partial dentures.

Modern prosthodontic therapy must continue to address the inevitable consequence of tooth loss--that is, alveolar process atrophy. The use of removable partial dentures (RPDs) to treat partial edentia must rely, in part, on support from the ever-deteriorating edentulous ridges. Extension-base RPDs are particularly affected as the tissue-base relationship changes over time after extraction of the natural teeth. This article reviews the concept of observed changes in the residual edentulous alveolar ridge and conventional procedures used to compensate for this bone loss. Finally, a practical procedure is presented which uses convenient and accurate materials that can be readily incorporated into the modern dental practice.

Aged↗
PubMed1992

[The prevention of mucosal lesions during oropharyngeal irradiation with a dental-filling shield].

In patients with metallic dental fillings radiation therapy to the oral cavity can cause mucous membrane lesions, which are more severe than expected. They appear as circumscribed erosions, opposite to metallic fillings and are caused by an increase in radiation dose through secondary radiation due to the higher density and atomic number of the filling material. This dose increase can be directly measured with 0.1 mm thin sheets of graphite-loaded TLD's (LiF, Vinten). For Co-60 gamma rays a commercial amalgam filling caused a dose increase by a factor of 1.7. The half value layer for this additional radiation was measured to be approximately 0.4 mm tissue. In order to avoid painful mucous membrane ulcerations which are even more a problem if hyperfractionated treatment schedules are used, we constructed individual dental shields for each patient. As shielding material we used a dental impression material (Optosil P+1 Bayer). This method was tested in 35 patients, in all of them circumscribed mucous membrane ulcerations could be avoided. The method proved to be fast and simple and was very well tolerated by all patients.

Dental Amalgam↗
PubMedDate not supplied

Variability in the shape of maxillary vestibular impressions recorded with modeling plastic and a polyether impression material.

Border molding is an important step in the fabrication of complete dentures. Conventional border molding using impression modeling plastic has been time-consuming and has resulted in a great variation in the shape of the recorded borders. This study compared the shape and variability of the vestibular impressions made with impression modeling plastic and a polyether impression material. Four prosthodontists each made five maxillary vestibular impressions using the two materials. All the impressions were made on one edentulous subject. The results showed significant differences at many locations along the border of the impressions. The borders of the impressions made with modeling plastic tended to be thicker and shorter than those made using polyether material. Use of the polyether material required less time to complete the border molding procedures and demonstrated a more consistent result in the shape of the vestibular impressions.

Dental Impression Materials↗
PubMed1985

Improved pantograph clutches fabricated intraorally.

A technique that improves intraorally made autopolymerizing resin pantograph clutches has been presented. The resulting clutches are comfortable and stable. Even after removing and reinserting the clutches several times, retention is sufficient to support the weight of the pantograph. Mandibular clutches have sufficient retention for accurate hinge axis location. If necessary, the same clutches can easily be relined for tracings during and after treatment. Replacing the relining material will adapt the clutches to changes in tooth contour that may occur as a result of treatment.

Acrylic Resins↗
PubMed2007

Influence of impression material and time on the 3-dimensional accuracy of implant impressions.

OBJECTIVE: To investigate, in vitro, the effect of time on the 3-dimensional accuracy of open-tray implant impression copings made of polyvinyl siloxane and polyether impression materials. METHOD AND MATERIALS: Reference models with 4 internal connection implants were fabricated. Four sets of 71 direct impressions were made with square impression copings using an open-tray technique. One set of impressions was made with polyether material (material A) and each of 3 polyvinyl siloxane materials (materials B, C, and D). Three-dimensional changes in spatial orientation of the implant analogs were measured over 48 hours using an optical measurement device. Deviation values were summed over 4 points and averaged per impression. Global differences were tested with a nonparametric Kruskal-Wallis test followed by pairwise comparisons using the Mann-Whitney U test. RESULTS: The mean dimensional accuracy of implant impressions significantly differed over time (P < .001). Materials A and B were found to produce comparable results, For materials C and D there was a significant increase in deviations, with a maximum increase at 2 hours. Deviations for material C were comparable to materials A and B at 48 hours. Baseline values were not maintained by any material. CONCLUSIONS: Within the limits of this in vitro study, it can be concluded that time cannot be neglected as a factor affecting the accuracy of implant master casts.

Dental Implants↗
PubMed2002

Pressure generated on a simulated oral analog by impression materials in custom trays of different designs.

PURPOSE: To measure the pressure exerted by maxillary edentulous impressions composed of 3 commonly used impression materials using four different impression tray configurations. MATERIALS AND METHODS: The study was performed using an oral analog that simulated an edentulous maxillary arch. Three pressure transducers were imbedded in the oral analog, 1 in the mid-palate area and the other 2 in the right and left ridge (maxillary first premolar areas). Custom trays of 4 different configurations were fabricated. The 3 impression materials tested were irreversible hydrocolloid, light-body and medium-body vinyl polysiloxane, and polysulfide. A total of 128 impressions were made. The custom tray and the oral analog were mounted using a reline jig. A Satec universal testing machine was used to apply a constant pressure of 2 kg/cm(2) over a period of 5 minutes on the loaded custom tray. The pressure was recorded every 10 seconds. Factorial analysis of variance and Tukey's multiple comparison test were used to analyze the results. RESULTS: A significant difference in the pressure produced using different impression materials was found (p < or =0.001). Irreversible hydrocolloid and medium-body vinyl polysiloxane produced a significantly higher pressure than light-body vinyl polysiloxane and polysulfide impression materials. The presence of holes and/or relief did not significantly alter the magnitude of pressure. CONCLUSION: All impression materials produced pressure during maxillary edentulous impression making. Tray modification was not important in changing the amount of pressure produced. The impression materials used had more effect on the pressure produced during impression making on the simulated oral analog.

Alginates↗
PubMed1998

Comparison of the new matrix system with traditional fixed prosthodontic impression procedures.

This article compares the methods and effectiveness of traditional fixed partial denture impression systems, which includes the matrix impression system, in relation to the registration of the finish lines and sulci of tooth preparations in the formation of a full arch impression. Concepts relating to custom trays, retraction, homeostasis, sulcular cleansing, sulcular flange registration, configuration and strength, viscosity of elastomeric impression materials, and delivering the impression material into the sulcus are reviewed. Several concepts are questioned and alternative procedures are proposed. Forces that impact the gingival tissues and determine the success of the impression are briefly described.

Dental Impression Materials↗
PubMed1998

Working times and dimensional accuracy of the one-step putty/wash impression technique.

PURPOSE: Using the one-step polyvinyl siloxane impression technique, this study compared the effect of putty material working time on the dimensional accuracy of recovered improved stone casts. MATERIALS AND METHODS: An acrylic resin master cast was fabricated with embedded reference points to enable both horizontal and vertical measurements. Four commercially available polyvinyl siloxane impression putties with light body washes were evaluated: 1) Extrude (Kerr), 2) Cutter (Coltere), 3) Express (3M), and 4) Reprosil (Caulk). Each putty was mixed by hand for 30 seconds, placed in a plastic stock tray, and seated on the master cast at 0, 30, 60, 90, and 120 seconds after mixing (N = 100, n = 5). The impressions were poured in improved stone, and vertical and horizontal measurements were made to 0.001 mm between reference points on recovered casts using an optical traveling microscope. ANOVA (p < or = .05) was used to compare vertical and horizontal measurements to master cast dimensions. RESULTS: No statistically significant difference was found among casts for all materials and time periods tested. When horizontal measurement ranges were evaluated, Extrude casts exhibited the widest range of measurement, especially when the trays were seated at 90 and 120 seconds. When vertical measurement ranges were evaluated, Express casts at 120 seconds exhibited the widest range. CONCLUSIONS: A high range of variability in vertical and horizontal dimensions occurred at the later time periods, especially for Extrude and Express casts. As a result of rapid polymerization and poor flow properties of putty materials, the impression tray should be seated within 60 seconds after putty mixing to reduce dimensional variability of recovered casts.

Analysis of Variance↗
PubMed2006

[A new method of imprint receiving for non-removable dentures].

An original method of precision imprint receiving is described that provides high dimensional precision under maximal dynamic pressure on impression material and its penetration into gingival crevice. Comparison of the new method of imprint receiving with different traditional methods of impression making for non-removable dentures is made.

Dental Impression Materials↗
PubMed1984

Dimensional stability of elastomeric impression materials in custom-made and stock trays.

Elastomeric impression materials for fixed prosthodontics are considered most stable when they have an even thickness of 2 to 4 mm. To obtain this, a custom-made impression tray is recommended. The purpose of the present study was to compare the stability of impressions made in custom trays and trays made of chromium-plated brass. The impression materials chosen were polyether and silicone. Two master models of the upper jaw were made of metal. The canines and first molars represented abutment teeth with flat occlusal surfaces. An engraved cross on each surface made it possible to measure in a microscope the distances between the abutment teeth on the models and in the impressions. The accuracy of the method was within +/- 8 micron. Twelve standardized impressions were made with each impression material in the two types of trays. The distances between the abutment teeth were measured immediately on removal of the impression, and after 1 and 24 hours. Although ample amount of impression material (2 to 9 mm) was allowed, the linear dimensional stability of the impressions made in stock trays was not inferior to the stability of impressions made in custom-made trays.

Acrylic Resins↗
PubMed1988

The plastic cap--an improved technique for impression taking.

An improved impression technique is described using a plastic, transparent, flexible cap in combination with silicone impression materials. The technique can easily be applied at the chairside by the clinician and provides a solution to some of the present problems in impression with minimal trauma to the surrounding tissues.

Dental Impression Materials↗
PubMedDate not supplied

Troubleshooting vinyl polysiloxane impressions.

For consistent results in impressions and restorations, the following four rules make a handy checklist: 1. Exclude as many variables as possible from your technique. 2. Review materials and techniques on a routine basis. 3. Discuss with laboratory technicians what they observe as they work with your impressions. 4. Pursue the satisfaction of keeping your skills at their highest level.

Dental Impression Materials↗
PubMed1998

Determining the accuracy of stock and custom tray impression/casts.

A study was conducted to evaluate the accuracy of casts made from stock tray and custom tray impressions using polysiloxane impression material. The results indicate that all casts distort but that impressions made from custom trays were more accurate and consistent in reproduction than were stock tray impressions.

Acrylic Resins↗