One-step Impression Technique Research Articles

Comparison of Linear Dimensional Accuracy Between One Step and Two-step Impression Technique Using Polyvinyl Siloxane Impression Material

Objectives: This study compares the linear dimensional accuracy between one step and two-step impression techniques using polyvinyl siloxane impression material. Methodology: The Randomized controlled trial was done in the Department of Prosthodontics, FMH College of Medicine and Dentistry Lahore and Pakistan Council for Science and Industrial Research Lahore. All impression samples which fall under the inclusion criteria in the Department of Prosthodontics, FMH College of Medicine and Dentistry Lahore and Pakistan Council for Science and Industrial Research Lahore were included. Samples were divided into two groups, i.e., Group 1 (single-step technique) & Group 2 (two-step technique). The impression's longitudinal length and inter-line distance were measured to assess the outcome i-e linear dimensional accuracy. Result: A total of 60 impression samples with polyvinyl siloxane impressions material were made. The linear dimensional accuracy in one step & two-step impression technique was seen in 5 (8.33%) & 13(21.66%) samples, respectively, (p=0.011). Conclusion: Compared to the one-step impression technique, the higher linear dimensional accuracy of the two-step impression technique uses polyvinyl siloxane impression material.

Clinical evaluation of one-step impression technique and definitive casts

Background/Aim: The purpose of this study was to evaluate the quality of impressions made with vinyl polysiloxane (VPS) material in clinical conditions by using the one-step impression technique, and the quality of casts generated from these impressions. The effect of operator, number and location of abutments, and presence of bleeding were also investigated. Material and Methods: A total of 150 fixed dental prosthesis (FDP) impressions were taken and considered acceptable by 3 experienced prosthodontists in a clinic in an institutional setting. The impressions were evaluated and rated by another experienced prosthodontist and respective casts were evaluated and rated by an experienced dental technician using a digital microscope with ×200 magnification. The defects observed were noted as bubbles, voids, tears, or other defects. A scale was structured for the impressions and casts with ratings of Alpha (excellent; no defects), Bravo (acceptable; small defects), Charlie (inadequate; defects that require remaking of impression), and Delta (unacceptable; substantial defects at preparation finish lines). The data were analyzed with the Chi-square test for inter-operator, number of abutments, and location of prepared tooth variables (a=0.05). Results: The scale ratings were 85 Alpha (57%), 52 Bravo (34%), 6 Charlie (4%), and 7 Delta (5%) for the impressions, and 81 Alpha (54%), 58 Bravo (39%), 4 Charlie (3%), and 7 Delta (5%) for the respective casts. Sixty-nine percent of the impressions and respective casts were rated with the same score. The scale rating results were not influenced by inter-operator variability or number of abutments. Location of the prepared tooth was significant for anterior/posterior (p=0.04), but was not significant for maxilla/ mandible (p>0.05). Bleeding at the preparation site had a significant effect on the acceptability of the impression (p=0.003). Conclusions: The acceptability of VPS impressions using onestep technique was independent of the operator, number of abutments, or whether the prepared tooth was in maxilla or mandible. Impressions of teeth in the anterior region were more acceptable than those located in the posterior. Bleeding negatively affected the acceptability of the impressions. Clinicians may use VPS impressions for the fabrication of FDPs using onestep dual-phase technique. However, clinicians should carefully evaluate their impressions when bleeding is present when using this technique.

Dimensional accuracy of three impression materials by one-step and two-step impression techniques: An in vitro study

Introduction: An accurate impression is essential to create a well-fitted dental prosthesis. This study aimed to compare the dimensional accuracy of three elastomeric materials using one-step and two-step impression techniques. Methods: In this study, 20 impressions were fabricated for each Vinyl siloxane ether (Identium), condensation silicone (Speedex), and additional silicone (Panasil) impression materials by the one-step and two-step impression techniques using perforated metal trays. The one-step impression technique was simultaneously performed with heavy body/light-body materials. In the two-step impression technique, acrylic copings with 2-mm thickness were placed on the abutments to obtain similar spacing for the light-body material. The dimensional accuracy of different impression materials and techniques were measured using distance differences of the stone dies from the master cast; subsequently, the results were compared with the reference model. Data were analyzed using a one-way analysis of variance and Dunnett’s tests (α=0.05). Results: All impression materials demonstrated an acceptable clinical accuracy. Identium (Vinyl siloxane ether) displayed the most accuracy in both the one-step and two-step impression techniques (P>0.05). The best accuracy for Panasil (additional silicone) was found to be the two-step impression technique (P>0.05), and the best accuracy for Speedex (condensation silicone) was reported as the one-step impression technique (P>0.05). Furthermore, the one-step impression technique was highly accurate in diameter dimension, as compared to the two-step impression technique. Conclusion: As evidenced by the results, the accuracy of impression is affected by the impression materials. Moreover, Identium (Vinyl siloxane ether) demonstrated the most accuracy in both one-step and two-step impression techniques.

One-step impression technique adapted with addition silicone

A quality molding is essential for the success of dental prosthesis manufacturing and its outcome is directly dependent on the dimensional stability, precision and flexibility of the impression materials as well as the technique used. Addition silicone is one of the most favored impression materials in dentistry. Its dimensional accuracy is superior to all other impression materials available in the market, being able to copy fine details of dental structures. Factors that influence the accuracy of a molding include proper material handling and the technique used. The aim of this paper was to report a modified molding technique that combines the qualities of one and two-step double viscosity molding techniques without adding time and cost. The technique consisted of accommodating the silicon heavy mass throughout the length of the stock tray by pressing it with fingers in the areas corresponding to the teeth forming a concave shape. Then the fluid silicone was added in the concavity area until it was completely filled. The adapted single step molding technique with addition silicone was effective, being easy to be performed in the clinical daily life. It makes possible to combine the advantage of the two-step molding technique in copying the details due to the predominance of fluid silicone and the advantage of the one-step technique in decreasing clinical time.

One-step versus two-step impression techniques; a literature review

ObjectiveThe aim of this literature review was to compare one-step impression technique versus two-step impression technique regarding their dimensional accuracy. MethodologyA Medline search was conducted through PubMed and Saudi Digital Library search engine using the following terms “impression techniques”, “conventional techniques”, “one-step”, “two-step” and “accuracy”. The search reviewed between 2008 and 20018. Twenty-nine articles were screened. Nine articles were assessed for eligibility out of which six were included. ResultsThree articles found that one-step impression technique had better dimensional accuracy than two-step impression technique. While the other articles showed that two-step impression technique had better dimensional accuracy than one-step impression technique. ConclusionWithin the limitations of this review, both one-step and two-step impression techniques exhibited acceptable dimensional accuracy. There are still controversies about the accuracy of one-step impression technique versus that of two-step impression technique, so more extensive in-vivo clinical studies should be performed.

Comparison of Dimensional Accuracy of Stone Models Fabricated by Three Different Impression Techniques Using Two Brands of Polyvinyl Siloxane Impression Materials

The aim of this study is to check the dimensional precision of stone models made by two different brands of polyvinyl siloxane impression materials using the monophase, one-step, and two-step putty/light-body impression techniques. A metal model, having two crown preparations, was fabricated. With each technique, 40 impressions were made using two types of polyvinyl siloxane impression materials (Aquasil and Virtual). A total of 240 impressions were made with both the polyvinyl siloxane impression materials. Monophase impressions were made with a medium body using an acrylic custom tray. By simultaneous usage of putty and light-body, one-step impressions were made with a perforated metal stock tray. For two-step impressions, a 25-40 microns thick cellophane sheet spacer was used. The stone casts were obtained from the impressions of the stainless steel model. Three different dimensions (height, diameter, and inter-abutment distance) on these resultant stone casts were compared with the standard die. The accuracy of two different brands of impression materials was also compared. The results were then statistically analyzed. The resultant casts obtained from the different impression techniques had significantly larger dimensions in height and diameter, but smaller dimensions were observed for the inter-abutment distance. Larger deviation in resultant casts was observed in the monophase than one-step impression technique and the least deviation was observed in the two-step impression technique. The two-step impression technique produced the most accurate results in terms of the resultant casts. Out of the two different brands, Aquasil produced more fare results. Adequate marginal adaptation, proper fit and least distortion of the castings, and the final prosthesis can be achieved by using the adequate impression technique and impression material.

Influence of the type of impression material on the precision of reproduction prosthetic field in one-step impression technique

Influence of the type of impression material on the precision of reproduction prosthetic field in one-step impression technique

The Effect of One‐Step vs. Two‐Step Impression Techniques on Long‐Term Accuracy and Dimensional Stability when the Finish Line is within the Gingival Sulcular Area

To evaluate the effect of two putty-wash impression techniques on the long-term accuracy and dimensional stability of poly(vinyl siloxane) (PVS) in the gingival sulcus area. Impressions were taken from a master cast to simulate molar crown preparation. A space around the abutment served as the gingival sulcus. Fifteen impressions using the one- and two-step impression techniques were taken using Express Regular, Express Fast, and President impression materials with custom trays. Using a Toolmaker's microscope, the long (LD) and short distances (SD) of the abutment and the planar distance between two parallel lines (PL) at the circumference of the cast were taken at 0.5, 2, 24, 48, 72, 96, 120, and 144 hours after mixing. ANOVA was performed, with the discrepancy between the distances of the impressions and the master cast as the dependent variable. The differences when different materials and impression techniques were used were significant (p < 0.001) for LD, SD, and PL, as was the interaction between the material, time, and technique (p < 0.001). SD discrepancies were higher than those of LD for all materials and times. The two-step impression technique was more accurate, with smaller discrepancies than the one-step impression technique. For all materials, the PL discrepancy was deemed acceptable (less than 0.5%) for all tested times. President had higher discrepancies than the other materials. When using the two-step putty-wash impression technique, pouring of the impressions may be postponed up to 30 hours; however, when using the one-step impression technique, pouring should be performed within 2 hours.

An Evaluation of Dimensional Accuracy of One-Step and Two-Step Impression Technique Using Addition Silicone Impression Material: An In Vitro Study

The study is aimed to evaluate the dimensional accuracy, the effect of undercut of two different configurations and the elastic recovery of addition silicone impression material assessed indirectly, by measuring the dimensions on stone models recorded from the impression of the master model, using one-step and two-step impression technique, for addition silicone impression materials. Measurements are taken to evaluate horizontal or linear and vertical dimensional changes, of the abutment V and abutment C from the stainless steel model. Heavy body/light body material is used for making one-step impression technique in a custom tray. Putty/light body is used for taking two-step technique in a stock metal tray. Improved die stone is used for pouring the impression. The different 11 locations on the dies produced by two different techniques are measured microscopically on image analyzer and compared with those of stainless steel model. Anova test was applied to test the differences of mean values of inter and intra abutment measurements, to calculate p value. Unpaired t test was applied to calculate t value. Results showed less deviation of stone models produced by one-step technique from stainless steel model, whereas the deviation of stone models produced by two-step is comparatively more. (p<0.01). This difference of deviation is significantly less in one-step as compared to two-step technique. One-step is sufficiently dimensionally accurate than two-step technique in conjunction with addition silicone impression material. They have the best elastic recovery from the two undercut configurations.

Accuracy of one-step versus two-step putty wash addition silicone impression technique

This study compared the accuracy of one-step putty wash with two-step putty wash impression techniques. Five addition silicone impression materials—Mirror 3 (MR), Mirror 3 Extrude (ME), Express (E), Permagum (P), and Absolute(A)—were tested. A stainless steel model containing two full-crown abutment preparations was used as the positive control. Five replications for one-step and two-step patty wash impressions of the master model were made for each test material. Accuracy of the materials was assessed by measuring six dimensions on stone dies poured from impressions of the master model. Accuracy of addition silicone impression material is affected more by material than technique. Accuracy of the putty wash one-step impression technique was not different from the putty wash two-step impression technique except at one of the six dimensions where one-step was more accurate than two-step. Mirror 3 putty wash two-step impression presented less distortion than Mirror 3 Extrude putty wash one-step or two-step impression.