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 1,279 records · Page 71Linked to original sources
PubMed1991

[Elastomers and peripheral seal in complete maxillary dentures].

First the various physical factors involved in retention are discussed. Adhesion is designed by the Gibert formula: [formula: see text] bringing the notion of interfacial surface delimited by the fluid meniscus (epsilon) and the thickness of the salivary film at the site of formation of the meniscus (h). Atmospheric pressure plays a role by the formation of a periphery seal ensuring the creation of a depression of the interfacial fluid in order to oppose the forces of pulling. As a summary, it is important to achieve the formation of a salivary meniscus: with the smallest curvature; continuous despite the mobility of the mucosa; beyond the limit between the free mucosa and the attached mucosa and the "farthest" possible from this area. The purpose of recording the periphery borders is to obtain the highest and widest possible denture flanges without any over-extension or over-thickness. The authors then propose performing a comparative study of the various materials available for recording the periphery of maxillary full dentures, in order to determine which best responds to the criteria of quality mentioned. Several recording techniques are possible, depending on the material used: either a segmented border recording (widely described); or a recording of the periphery seal in one or several stages which is then illustrated by the use of Impregum. For each patient, recordings of the periphery was made according to a protocol always identical and precise; only the material used for this purpose (Kerr compound, regular Neo-Plex and Impregum) varied. The measure taken from these recordings showed that Impregum demonstrates the highest and thickness borders as opposed to Neo-Plex and Kerr compound which provided intermediary results. Thus, Impregum appears to be the material of choice for the optimal recording of the functional periphery seal in maxillary full dentures.(ABSTRACT TRUNCATED AT 400 WORDS)

Dental Impression Materials↗
PubMed1997

Complete denture impressioning technique.

This article describes a technique that simplifies the making of an edentulous arch impression before the fabrication of a complete denture. Making an impression of an edentulous arch requires a unique combination of managing movable soft tissue commensurate with integrating different materials and a technique for accurate reproduction. The technique described requires a two-phase approach using a syringeable addition silicone during the border molding process and a condensation silicone wash material to capture the soft tissue while the functional border molding is repeated. These more recently developed products allow us to achieve similar results and are easier, faster, and more predictable than those products used previously.

Dental Impression Materials↗
PubMedDate not supplied

Skin grafting in severely contracted socket with the use of 'Compo'.

The results of split thickness autologous skin grafting along with the use of a dental impression material (Compo), a thermoplastic substance are presented in a series of 11 patients of acquired, severely contracted, anophthalmic sockets. Only the fornix fixation sutures and the central tarsorrhaphy were employed for the proper placement of graft without the use of retention devices. Artificial eyes were successfully fitted and retained subsequently after 6 weeks of grafting.

Adolescent↗
PubMed2005

Photogrammetry and conventional impressions for recording implant positions: a comparative laboratory study.

BACKGROUND: The development of digitized techniques for manufacturing implant frameworks has made possible alternative "impression" techniques for recording implant positions. PURPOSE: The objective of the present study was to test the precision and accuracy of a three-dimensional photogrammetric technique to record implant positions in vitro and to compare casts made with this technique with conventional casts fabricated with two conventional impression techniques. MATERIALS AND METHODS: Twenty casts were fabricated from 10 polyether (Impregum, ESPE Dental AG, Seefeld, Germany) impressions and 10 plaster (Kühns Abdrucksgips, Ernst Hirnischs GmbH, Goslar, Germany) impressions of one master model. The casts were measured in a coordinate measuring machine (Zeiss Prismo VAST, Oberkochen, Germany) and compared with the master model. Six separate three-dimensional photographs of the master model were taken with a special camera. After the photographs were measured with an analytic plotter, results were analyzed and compared to the coordinates of the original model and casts. RESULTS: A systematic pattern of distortion in the x-axis was found for the two impression techniques. Expansion of the implant arch at the terminal implants (p < .01) averaged 22 microm and 94 microm on photographs and plaster casts, respectively. Polyether casts contracted an average of 52 microm when compared with the master (p < .01). In absolute figures, photogrammetry and the polyether technique reproduced the x-axis and three-dimensional parameters more accurately than the plaster technique did when cylinder center point distortion was compared (p < .05 to p < .001). However, angular cylinder distortion in absolute figures was greater with the photographic technique than with either of the impression techniques (p < .05-p < .001). CONCLUSION: Photogrammetry is a valid option for recording implant positions and has a precision comparable to that of conventional impression techniques. At present, however, it is limited to framework fabrication techniques that are based on digital platforms.

Calcium Sulfate↗
PubMedDate not supplied

Gingival sulcus simulation model for evaluating the penetration characteristics of elastomeric impression materials.

PURPOSE: This study evaluated the ability of five elastomeric impression materials to penetrate the gingival sulcus beyond the preparation margin. MATERIALS AND METHODS: A model of brass and agar gel was made to simulate human sulci and clinical gingival conditions. Two addition-curing silicones, one condensation-curing silicone, one polyether, and one polysulfide were tested. Ninety impressions of the model were made, six impressions with each material with differing sulcular widths. The centers of sulcular extension of these impressions were found with a measuring microscope. RESULTS: Two-way ANOVA showed significant differences among impression materials, sulcular widths, and their interactions. The penetration ability of polyether showed greater extension than the other materials, regardless of sulcular width. Polysulfide penetrated less than the two silicones with 0.2- and 0.1-mm sulcular widths but more with the narrow 0.05-mm sulcular width. CONCLUSION: These results suggest that the viscoelastic behavior of elastomers depends on the width of sulci. Moreover, the sulcus simulation model effectively contributes to the investigation of their characteristics.

Analysis of Variance↗
PubMed2002

Effect of rinsing hydrocolloid impressions using acidic electrolyzed water on surface roughness and surface hardness of stone models.

The present study investigated the effect on the surface quality of resultant stone models of rinsing hydrocolloid impressions using acidic electrolyzed water. Two brands of alginate impression materials (Aroma Fine DFIII, Jeltrate Plus), an agar impression material (Ajisai) designed for agar/alginate combined impression, and dental stone (New Plastone) were used to make the test specimens. For the rinsing of impressions, acidic electrolyzed water having a pH value of 2.3, an oxidation-reduction potential of 1,230 mV, and a residual chlorine concentration of 45.0 ppm, was prepared. Alginate, agar and agar/alginate combined impressions were rinsed using acidic electrolyzed water or tap water for 30 sec and 3 min, and as a control, these impressions were not rinsed with any water. Disk-shaped stone specimens obtained from rinsed impressions were evaluated with respect to surface roughness (Ra) and surface hardness (scratch depth), and scanning electron microscope (SEM) observations were performed. The stone specimens obtained from rinsed impressions using acidic electrolyzed water showed a surface quality equivalent to that of the stone specimens obtained from the rinsed impression using tap water. This result suggests that the use of acidic electrolyzed water for rinsing is an acceptable treatment for hydrocolloid impressions, so long as the rinsing time is from 30 sec to 3 min.

Agar↗
PubMed1979

Adhesion between copper-plated acrylic tray resin and a polysulfide rubber impression material.

The method of copper plating on acrylic resin was developed, and the bond strength to polysulfide rubber was measured in comparison with that of the adhesive coating. The bond strength with copper plating was greater than with adhesive coating. The specimens with adhesive coating failed due to a rupture occurring at the elastomer-adhesive interface, while those with copper plating had cohesive-adhesive failure. The method of copper plating on acrylic resin improved the adhesion between the polysulfide rubber and the custom-built acrylic resin tray.

Acrylic Resins↗
PubMed2002

Dimensional accuracy of dental casts: influence of tray material, impression material, and time.

PURPOSE: This study evaluated the influence on dimensional accuracy of dental casts made with different types of trays and impression materials and poured at different and multiple times. MATERIALS AND METHODS: Two types of stock trays (plastic stock tray, perforated metal stock tray) and 4 types of custom tray materials (autopolymerizing acrylic resin, thermoplastic resin, and 2 types of light-polymerized acrylic resins) were used with 2 types of impression materials (addition polymerizing silicone and polyether), to make impressions of a metal master model. Each tray and impression material was used to make 5 impressions. Casts were made by multiple pourings at 30 minutes, 6 hours, 24 hours, and 30 days after impression making. Using a measuring microscope, 12 distances were calculated based on measurements of 8 reference points. The absolute value of the difference of each measurement was calculated, as was the corresponding measurement on the master model. A Bayesian model using a simple noninformative prior was used to analyze these data. RESULTS: Statistical differences within 6 microm were found only with thermoplastic resin tray material for addition silicone, and for thermoplastic resin tray material and 1 type of light-polymerized acrylic resin for polyether. Neither stock trays nor custom trays contributed to the differences in accuracy of the casts. All deviations in casts made with silicone impression material were within a clinically acceptable range. For the polyether, distortions occurred that were clinically unacceptable. Impressions made from polyether distorted over time. Silicone impression material has dimensional stability up to 30 days. CONCLUSION: Accurate casts can be made with either stock trays or custom trays. An impression made from polyether should be poured only once and within 24 hours after impression making, because of the distortion of the material over time. Silicone impression material has better dimensional stability than polyether. .

Acrylic Resins↗
PubMed2003

A laboratory investigation of the accuracy of the repositioning impression coping technique at the implant level for single-tooth implants.

This study investigated the accuracy of the repositioning impression technique at the implant level using vinyl polysiloxane impression material. Three groups each of ten senior dentists, postgraduate students and technicians were asked to use this technique to record the position of an implant in a master model. The Reflex Microscope was used to measure variations between the resulting casts and the master model. Significant difference between the casts and the master model in the X and Y-axes (p < 0.01) was recorded. Alarming inclinational and rotational errors for the implant analogue position were measured with all groups of operators. Similar distortion in the Z-axis was recorded.

Analysis of Variance↗
PubMed2000

Evaluation of interarch space for implant restorations in edentulous patients: a laboratory technique.

This article describes a laboratory procedure for the visual evaluation of interarch space and its effect on implant prosthesis design. The method is applicable to patients presenting with completely edentulous arches. Silicone impression material is used to form a resilient cast and an external mold from an existing denture. The denture is duplicated using autopolymerizing acrylic resin. The duplicate denture and resilient cast are mounted on an articulator. Spatial relationships of anatomic landmarks can be evaluated, and a quantitative evaluation of available space can be made. The duplicate denture can also be used as a surgical template to direct implant placement. Reference tables are provided to serve as guidelines in the correlation between available space and minimum space required for various implant-assisted restorations.

Acrylic Resins↗
PubMed2005

Influence of margin design on the fit of high-precious alloy restorations in patients.

OBJECTIVE: It was the objective of this study, to analyze the influence of the marginal design on the marginal accuracy of a casting in a clinical setup in patients. METHODS: Ninety volunteer patients' teeth-which were intended for extraction due to medical reasons-were prepared prior to extraction. Three different types of finishing line-chamfer, 135 degrees shoulder and 90 degrees shoulder-were employed. Two each c-silicone and pvs impressions were taken of each tooth using either a two-stage or a one-stage putty-wash technique. After preparation and impression taking the teeth were extracted. Gypsum casts were poured from the impressions and high precious alloy castings fabricated on the dies and marginal discrepancies were determined on the extracted teeth. RESULTS: The median value of marginal discrepancies was lower than 150 microm for all groups. The difference between the three different preparation types was significant (H-test, p<0.05). The lowest median values were obtained for the chamfer preparations, while the 90 degrees shoulders always produced the highest median values. Preparations at gingva level exhibited more accurate marginal fit than subgingival preparations. No significant differences could be observed between the pvs and c-silicone materials or the one-step and two-step putty-wash techniques. CONCLUSIONS: The marginal designs of the preparations had much less influence on the marginal fit of high precious alloy castings than expected. There is considerable reason to assume that technical but clinical parameters influence the quality of fixed prosthodontics much more than has been believed in the past.

Adult↗
PubMed1979

Replica study of plaque formation on human tooth surfaces.

Plaque formation on buccal tooth surfaces was studied by replica technique, consisting of impressions using low viscosity silicone impression materials and positive models produced in epoxy resins. Bacterial accumulation occurred near the cemento-enamel junction in 6-hr specimens, and subsequently expanded in a coronal direction. This development took place partly by extensions of single layers of bacteria, and partly by a pattern where the colonization was mostly restricted to vertical enamel cracks. Plaque accumulations were also frequently located in abrasion grooves and surface pits in the enamel, and prolific plaque areas were consistently surrounded by a monolayer of bacterial cells. Globular and hemispheric structures which occurred, especially on root surfaces immediately after cleaning, were probably artefacts caused by air bubbles or remaining moisture. In separate series of experiments it was demonstrated that improved reproduction of details from the plaque could be achieved by repeating the replicating procedure. The findings indicate that plaque formation starts by adsorption and proliferation of individual bacteria on tooth surfaces, and not by adsorption of aggregates of cells. Special attention should be directed against the problem of artefacts and moisture in replica studies of dental plaque.

Dental Impression Materials↗
PubMed2002

Accuracy of 3 conceptually different die systems used for implant casts.

STATEMENT OF PROBLEM: Given that meticulous implant prosthodontic procedures are recommended to obtain the best possible intraoral fit, the die systems used for multi-implant casts warrant further investigation. PURPOSE. The purpose of this in vitro study was to compare the accuracy of implant casts fabricated from 3 conceptually different die systems at the solid, sectioned, and repeated stages. MATERIAL AND METHODS: Thirty direct transfer implant impressions were made of the master cast with a polyether impression material. Ten experimental implant casts were fabricated for each of the 3 different die systems tested: double-pour (Pindex), plastic base (DVA), and die tray (KO Tray). The solid experimental casts were sectioned and then removed from the die system 30 times. Linear distances between steel balls placed on each abutment replica were measured with a traveling microscope to determine the accuracy of the experimental casts at different stages. Data were analyzed with repeated-measures analysis of variance (alpha=.05) and the post hoc Ryan-Einot-Gabriel-Welsch multiple-range test (REGWQ). RESULTS: Repeated-measures analysis of variance revealed a significant interaction between the die systems and different stages (P=.0432). REGWQ showed the die tray system to be significantly more accurate at the solid than at the sectioned and repeated stages. The die tray system was significantly less accurate than the double-pour and plastic base systems at the sectioned stage. CONCLUSION: Within the limitations of this study, the use of a double-pour or plastic base die system is recommended when sectioned dies are needed for a multi-implant-retained prosthesis.

Acrylic Resins↗
PubMed1984

Clinical evaluation of the accuracy of interocclusal recording materials.

The importance of accurate, reliable recording mediums cannot be understated. Function and esthetics are directly related to this critical step. Dental recording materials must be accurate, easily manipulated, and economical for effective use. Five types of intraoral records of 31 patients were registered and placed on an arcon, semiadjustable articulator to measure the magnitude and direction of distortion. The results were the following. Polyether interocclusal recording medium without a carrier was the most accurate. Polyether and zinc oxide-eugenol pastes with carriers were the next most accurate recording mediums, but they required a disciplined technique. Recording waxes were consistently unreliable. Distortion occurred more frequently in a vertical direction, followed by an anteroposterior direction.

Clinical Trials as Topic↗