Elastomeric Impression Materials Research Articles

Comparative Evaluation of Dimensional Stability of Elastomeric Impression Materials Subjected to Ultraviolet Irradiation and Spray Atomized Disinfection: An In Vitro Study

Comparative Evaluation of Dimensional Stability of Elastomeric Impression Materials Subjected to Ultraviolet Irradiation and Spray Atomized Disinfection: An In Vitro Study

In vitro Evaluation of Implant Impression Techniques and Elastomeric Materials: A Comparative Dimensional Accuracy Study

Abstract Context: Dimensional precision in implant impression. Aims: The purpose of this study was to comparatively evaluate the dimensional accuracy of two implant impression techniques with two different variants of vinyl polysiloxane impression material. Material and Methods: The edentulous mandible reference model was fabricated in clear resin. In the anterior region of the mandibular ridge, three dummy implants were placed in a spread-out configuration. Impressions were made using two elastomeric impression materials and two impression techniques using customised impression trays. Finished casts were then divided into four groups having four samples each. The mean centre-to-centre distances between adjacent analogues (in sample casts) and between adjacent implants (in the control cast) were measured with the help of a profile projector. Statistical Analysis Used: Data were analysed using Student’s t-test. Results: The open-tray technique showed more accurate results with a combination of medium body and light body, whereas in the closed tray technique, mono-phase vinyl polysiloxane appeared to be a better option. Amongst all, mono-phase with closed tray provided statistically significant results. P < 0.05 in Group C and other group’s P ≥ 0.05. Conclusions: Within the limitations of this study, both implant impression techniques appeared to be equally accurate depending on clinical conditions, temperature and time of the procedure. However, mono-phase impression material with closed tray provided statistically significant results.

Technique for Spacer Adaptation and Custom Tray Fabrication in Impression Making for Fixed Prosthodontics

Abstract The objective is to minimize the inaccuracies in two-step impressions by homogenizing the polymerization shrinkage of elastomeric impression material in fixed prosthesis fabrication. The objective is accomplished by the technique of spacer adaptation and custom tray fabrication for two-step impressions. The technique makes the use of two vacuum-adapted spacers, selected based on the viscosity of elastomeric impression, and a vacuum-adapted custom tray. The procedure of using the specially fabricated custom tray for impression making is also presented. Consistent thickness of the two different viscosities of impression material is maintained due to vacuum adaptation of the spacers. This homogenizes the polymerization shrinkage of the elastomeric material in different regions of impression, as uniform space is occupied by the material in the space created by the spacer. The procedure of vacuum adaption of the tray material also limits the dimensional change of the tray. The technique minimizes the inaccuracies of impression by homogenizing the polymerization shrinkage of the elastomeric impression, thus promising a well-fitting prosthesis.

Assessment of dimensional stability of novel VPES impression material at different time intervals with standard disinfectants

BackgroundVinyl polyether silicone (VPES) is a novel impression biomaterial made of a combination of vinyl polysiloxane (VPS) and polyether (PE). Thus, it is significant to assess its properties and behaviour under varied disinfectant test conditions. This study aimed to assess the dimensional stability of novel VPES impression material after immersion in standard disinfectants for different time intervals.MethodsElastomeric impression material used –medium body regular set (Monophase) [Exa’lence GC America]. A total of 84 Specimens were fabricated using stainless steel die and ring (ADA specification 19). These samples were distributed into a control group (n=12) and a test group (n=72). The test group was divided into 3 groups, based on the type of disinfectant used - Group-A- 2% Glutaraldehyde, Group-B- 0. 5% Sodium hypochlorite and Group-C- 2% Chlorhexidine each test group was further divided into 2 subgroups (n=12/subgroup) based on time intervals for which each sample was immersed in the disinfectants – subgroup-1- 10 mins and Subgroup 2- 30 mins. After the impression material was set, it was removed from the ring and then it was washed in water for 15 seconds. Control group measurements were made immediately on a stereomicroscope and other samples were immersed in the three disinfection solutions for 10 mins and 30 mins to check the dimensional stability by measuring the distance between the lines generated by the stainless steel die on the samples using a stereomicroscope at x40 magnification.ResultsThe distance measured in the control group was 4397.2078 µm and 4396.1571 µm; for the test group Group-A- 2% Glutaraldehyde was 4396.4075 µm and 4394.5992 µm; Group-B- 0. 5% Sodium hypochlorite was 4394.5453 µm and 4389.4711 µm Group-C- 2% Chlorhexidine was 4395.2953 µm and 4387.1703 µm respectively for 10 mins and 30 mins. Percentage dimensional change was in the range of 0.02 – 0.25 for all the groups for 10 mins and 30 mins.Conclusions2 % Glutaraldehyde is the most suitable disinfectant for VPES elastomeric impression material in terms of dimensional stability and shows minimum dimensional changes as compared to that of 2% Chlorhexidine and 0.5% Sodium hypochlorite.

The Accuracy of Casts Obtained Using Different Impression Techniques and Impression Materials in Combined Parallel and Angulated Implants: An In Vitro Study.

Aim The aim of this in vitro study was to evaluate and compare the accuracy of casts made from two elastomeric impression materials (polyvinyl siloxane (PVS) and vinylsiloxanether (VSE)) using different impression techniques on parallel and angulated implants. Materials and methods The reference model was fabricated using auto-polymerizing acrylic resin on which three implant analogs were placed of which two were parallel to each other and the third at 20-degree mesial angulation. A total of 60 impressions were madeof which 30 were by using PVS and 30 by VSE. For each material, 10 impressions were made by closed tray technique, 10 by open tray techniqueand 10 by open tray with sandblasting and adhesive coating of the impression copings technique. The inter-analog distances of the casts obtained were evaluated and compared with the reference model by a vision measuring machine. Data were analyzed using analysis of variance (ANOVA), Tukey's Honest Significant Difference (HSD) post hocand independent samples t-test. Results When the inter-analog distances of the duplicate casts were compared with the reference model, the mean error rates for parallel implants decreased in the order of closed tray technique, open tray technique and open tray with sandblasting and adhesive coating of the impression copings technique for both PVS and VSE impression materials. Similarly, the same order was observed for angulated implants for both impression materials. Using the closed tray technique, there was no statistically significant difference in the accuracy of the cast between the two materials for parallel implants (P = 0.525) and also no significant difference between the two materials for angulated implants (P = 0.307). Similarly, there was no statistically significant difference in the accuracy of the cast between the two materials for parallel implants (P = 0.455) and also no significant difference between the two materials for angulated implants (P = 0.519) using the open tray technique. Whereas for the open tray with sandblasting and adhesive coating of the impression copings technique, VSE produced a more accurate cast than PVS for parallel implants and was statistically significant (P = 0.033); however, there was no significant difference between the two materials for angulated implants (P = 0.375). Conclusion For parallel implants, VSE by an open tray with sandblasting and adhesive coating of the impression copings technique produced a more accurate cast than PVS. For angulated implants, there was no significant difference between the two materials and it was only the technique that significantly affected the accuracy of the cast.

Elastomeric impression materials used in modern orthopedic dentistry

This article presents a review of elastomeric impression materials currently used in orthopedic dentistry. The elastomer group is divided into silicone, polyester, and thiocol (polysulfide) materials. Silicone impression materials are widely used in orthopedic dentistry. Their structural basis is polymethylsiloxane with active terminal hydroxyl groups. Polyester materials consist of the main and catalyst components (pastes). The main component contains a polymer with imine groups, fillers, and plasticizers. Sulfonic acid ester is present in the catalyst paste. When these two components are mixed, ionic (cationic) polymerization occurs. Polysulfide materials are produced as base and catalyst pastes. The structural unit of the main paste is polysulfide or mercaptan rubber, and the catalyst paste acts as an oxidizer. Lead dioxide is often used as an oxidizer. The resulting polymer does not have a stereoregular structure, which causes its stickiness. It is technologically challenging to obtain a polymer with a stereoregular structure.
 When theoretically comparing the listed types of elastomeric impression materials, according to their properties, chemical composition, advantages, and disadvantages, polyester and polysulfide impression materials can be distinguished as more advanced. Silicone materials have disadvantages; however, they are often used for domestic dentistry owing to the presence of domestic manufacturers and relatively low cost.

Precision Prosthodontic Rehabilitation of Flabby Ridge with a Modified Window Technique: Case Report

Flabby ridge, also known as a soft (mobile), movable, or displaceable ridge, presents a common clinical challenge in dental practice. It primarily affects the alveolar ridges of the upper (maxillary) or lower (mandibular) arches. The anterior region of the maxilla is especially susceptible in edentulous patients. The flabby ridge lacks the firmness and stability required, leading dentures to become loose and unstable. Consequently, this instability can result in discomfort, speech and eating difficulties, and reduced quality of life for denture wearers. The flabby ridge often does not provide the necessary contour and resilience needed to establish an effective seal and maintain suction between the denture base and the underlying tissues. This compromises denture retention, making them susceptible to dislodgement during typical oral functions. Therefore, rehabilitating a completely edentulous patient with flabby tissue presents a formidable challenge for prosthodontists, as it undermines the retention, stability and support of complete dentures. Methods for managing flabby ridges encompass surgical removal, ridge augmentation, specialized impression techniques, balanced distribution of occlusal loads and implant therapy. Various impression techniques have been proposed to address the complexities of such cases. By carefully applying the principles of complete denture construction, a palliative treatment approach can be achieved. Special impressions often employ the window technique to capture a static impression of the flabby area, which introduces its own set of challenges. This innovative case report introduces a modified window technique that incorporates precise record transfer of the flabby ridge using tissue (blotting) paper. Specifically designed for the anterior mandibular flabby ridge, the technique employs a custom tray with a window positioned over the flabby tissues. A mucostatic impression material is utilized to minimize pressure on the flabby tissue, thereby reducing potential tissue distortion during the impression process. The procedure is executed in two steps: first, stable structures are recorded, followed by capturing the mobile tissues using light-body polyvinyl siloxane (PVS) elastomeric impression material within the window area. This method ensures an accurate record of the denture-supporting structures while maintaining the contour and details of the flabby tissues without displacement. Importantly, the technique is crafted for straightforward implementation by general dental practitioners within a primary dental care setting.

Evaluation of Dimensional Change in Different Elastomeric Impression Materials Used in Implants: An Original Research

ABSTRACT Aim: The study’s objective was to assess the dimensional accuracy of hybrid polyether and polyvinyl siloxane materials for implant impressions. Materials and Methods: Nine groups were created from 45 samples of various building materials and construction techniques from the study. Five samples were tested, and 45 impressions were recorded. Results: The hybrid non-splinted technique has improved implant site replication, accuracy, and low interimplant distance alterations. Conclusion: The finest possible reproduction of implant sites on the master cast was made feasible by the use of an open, non-splinted method and a hybrid polyvinyl siloxane–polyether impression material.

Efficacy of Ozone, UV Radiation, Herbal and Glutaraldehyde Method for Sterilisation of Elastomeric Impression Materials for Orthodontic and Prosthodontic procedures

ABSTRACT Objectives: The objectives of the current study was to evaluate the disinfection efficacy of ozone, ultraviolet (UV) radiation, herbal and glutaraldehyde method for sterilization of elastomeric impression materials Materials and Methods: Disinfection of elastomeric impression material was performed with each of the disinfection methods: ozone, UV radiation, herbal, and glutaraldehyde. Later microbiological analysis was performed and the colony-forming units were evaluated and compared. Results: The highest disinfection efficacy was found with glutaraldehyde, followed by ozone and UV radiation, and the least with neem herbal rinse. Intergroup comparison was highly significant Conclusion: Dry gaseous ozone and UV radiation can be used effectively for the disinfection of impressions.

An Evaluation of Retention of Complete Denture Bases Made with a “Modified Single-stage Impression” Technique Using a Heat-moldable Tray

Abstract Aim: Although most dental schools teach complete denture definitive impression techniques consisting of secondary impressions in border-molded custom impression trays, it has been found that later, graduates in clinical practice abandon this step because of its complexity and attempts to seek easier alternatives. To simplify two-stage techniques, single-step border molding with elastomeric impression materials and light-cured resin materials has gathered acceptance among clinicians. The study aims to evaluate the retention of record bases made with a modified single-stage impression technique that uses elastomeric impression material in a heat moldable tray with modeling compound as material for border molding. Settings and Design: This was an in vivo preliminary cohort study. Materials and Methods: Thirteen completely edentulous patients requiring complete dentures were included in the study. A traditional two-stage impression was made using custom trays fabricated over diagnostic casts and further border molding done with a modeling compound, and the final impression was made to use zinc oxide–eugenol impression material. Additionally, a modified single-stage impression technique using heat moldable impression trays was made. Master casts from each technique were made, and further record bases were made on each master cast. Wire loops were adapted on the palatal aspect of record bases. The retention of each record base was evaluated using a force gauge. Statistical Analysis: The Kolmogorov–Smirnov test was used to analyze the normality of variables and later Wilcoxon signed-rank test was applied. Results: The double-stage technique exhibited retention values in the range of 0.6–66.7 units, whereas the single-stage technique showed a range of 0.15–78.55. The tests showed no significant difference between double-stage and single-stage techniques (P > 0.05). Conclusions: The single-stage technique using heat moldable trays with elastomeric impression material and modeling compound as a material for border molding can produce denture retention compared to the conventional technique that uses a two-step impression technique. The use of the modified single-stage technique can additionally save an extra appointment for patients, although it is better to use such a technique as an advanced impression technique and not as a training technique for beginners or students, as the material cost is substantially higher than the conventional two-stage technique.

Evaluation of Elastic Recovery of Elastomeric Impression Materials Subjected to Various Disinfection Methods: An In-vitro Study

Evaluation of Elastic Recovery of Elastomeric Impression Materials Subjected to Various Disinfection Methods: An In-vitro Study

A SimpleImplant Guide for Infrazygomatic Bone Screw Placement with High Precision—A Clinical Innovation

Absolute anchorage systems like mini-implants, bone screws, and mini-plates have been a landmark evolution in the modern orthodontic world providing an added armamentarium in the hands of orthodontists to treat their patients with utmost efficiency. Unlike other systems, the extra radicular placement and limited surgical exposure make the bone screws such as infrazygomatic crest screws (IZC screws) superior, and to capitalize on these benefits, stability of the implant is vital that relies on their precise placement and angulation. Hence, this article presents a simple implant guide with elastomeric impression material for the precise positioning of IZC screws with utmost ease in fabrication.

Quantification of flowability and hydrophilicity of elastomeric impression materials.

Abstract Introduction: Flowability and hydrophilicity are essential properties of accurate impressions and casts. Aim of study: This study aimed to quantify these characteristics of elastomeric impression materials. Material and Methods: A total number of eight impression materials, including vinyl polysiloxane (PVS), polyether (PE), and condensation silicone (CS) were thoroughly investigated in this study. The flowability of elastomers was proven with the shark fin test (SFT), and the hydrophilicity was determined with contact angle (CA) measurements. Results: The shark fins’ (SF) of VPSs presented 11.57 mm (SD 3.49), while the PE 11.37 mm (SD 5.06) and CS 8.1 mm average values. Some of the products showed better flowability. Based on 128 measured CAs, the examined polyethers had the lowest CAs which indicate good hydrophilicity. Conclusions: A good performance of an impression material in one of the involved tests (SFT and CA) does not mean a similar result in the other analysis. All investigated impression materials could be considered hydrophilic as their CA was lower than 90°. The SFTs of light-bodied VPSs and PEs suggest reliable use of them in dental practice.

A Comparative Evaluation of Dimensional Change of Addition Reaction Elastomeric Impression Material After Disinfecting With 1% NaOCL and 3% H2O2: An in Vitro Study

Elastomeric impression materials are most commonly used impression materials in clinical practice for treating partially edentulous patient. After making impression it needs to be sterilized properly to minimize the risk of cross infection. Dimensional stability and accuracy of an impression after chemical disinfection by using different disinfectants are crucial for the accuracy of final prosthetic restoration. Until 1991 the recommended procedure for disinfection of impression was rinsing under running water with which only 40% of bacteria, virus, and fungi were removed and potential for transmission of microorganism remained there. Now a days most clinically used disinfection solutions are 3% hydrogen peroxide and 1% sodium hypochlorite. These two solutions are more effective to diminish microorganisms from the impression surface without altering dimensional stability.

Effect of Gingival Hemostatic Agents on the Surface Detail Reproduction and Dimension Stability of Three Elastomeric Impression Materials.

This study aimed to evaluate the effects of aluminum chloride based hemostatic agents on the surface detail reproduction and dimension stability. Three impression materials were investigated after contaminated with three commercial astringents with different concentration of aluminum chloride. The specimens from three impression materials were fabricated with a stainless-steel mold that followed the American Dental Association specification no.19. The mold was preliminarily contaminated with three hemostatic agents racestyptine, Dryz, and Expasyl™-and 80 specimens from each impression material-polyvinylsiloxane (PVS), polyether, and polyvinylsiloxane ether (PVSE), were fabricated and subjected to each astringent. The surface detail reproduction was examined using a stereomicroscope at 4x magnification, and the dimensional stability was analyzed at 24 hr with a measuring microscope. The surface detail data were statistically analyzed with Fisher's test at a significance level of 0.05. The dimensional stability data were analyzed using two-way ANOVA and Tukey's test at a significance level of 0.05. Aluminum chloride hemostatic agents can affect the surface detail reproduction of impression materials differently (p < 0.05). Thus, the first null hypothesis was rejected. PVS showed the highest percentage of satisfactory surface detail regardless of the hemostatic agent used in this study. PVSE showed a reduced percentage of satisfactory surface detail when the concentration of aluminum chloride was high. The three hemostatic agents affected the dimensional stability of each material differently (p < 0.05). Therefore, the second null hypothesis was also rejected.

Effect of chemical disinfection on the dimensional stability of polyvinyl ether siloxane impression material: a systemic review and meta-analysis

Background and objectivesPolyvinyl ether siloxane (PVES) possesses ideal characteristics for making precise and accurate dental impressions. PVES dimensional stability owes to its better polymeric properties derived from its parent materials poly ethers and polyvinyl siloxanes. As recommended use of chemical disinfecting agents is getting more popular, there is a growing concern associated with the effect of disinfectants on PVES dimensional stability. This study was aimed to understand the PVES behavior when subjected to chemical disinfectants.Materials and methodologyThe data was collected from research studies retrieved from Google Scholar, Scopus, and PubMed using MeSH terms of keywords “vinyl polyether siloxane AND Disinfection” or (Vinyl polyether siloxane OR polyvinyl siloxane ether OR PVES) AND (disinfectant OR disinfection)” without any restriction to publication date. The PRISMA (Preferred Reporting Items for Systemic Review and Meta-Analysis) directions were observed during the data collection, screening of studies, and meta-analysis. The primary data were retrieved, and batch exported from databases using Harzing’s Publish or Perish software; primary analysis was performed in Microsoft Excel, while statistical analysis for effect size, two-tailed p-values, and heterogeneity among studies was performed using Meta Essentials. The effect size was calculated using Hedge’s g values at the 95% confidence level using the random-effects model. Heterogeneity among studies was measured using the Cochrane Q and I2.Results and conclusionDental impressions made from the PVES elastomeric impression materials showed no significant changes in dimensional stability. Immersion in the chemical disinfectant for 10 min was associated with clinically irrelevant changes in the dimensions of the PVES impressions. Disinfection with sodium hypochlorite was associated with clinically significant changes in dimensions, with a two-tailed p-value of 0.049. Disinfection with 2–2.5% glutaraldehyde solution was not associated with any significant dimensional variability.

Comparative Evaluation of the Rigidity and Accuracy of Different Elastomeric Impression Materials with Open Tray Implant Level Impression Technique-An In vitro Study.

An implant-supported prosthesis requires a precise imprint to provide a good fit. It has been suggested that for implant/abutment level impressions, both the indirect (closed tray) and direct (open tray) methods are effective in achieving a passively fitting prosthesis. With an open plate embed level impression technique, this in vitro investigation set out to evaluate three different elastomeric imprint materials for their relative rigidity and precision. Sixty bespoke trays were created. Part I (rotational opposition assessment) of the investigation included selecting 30 uniquely shaped plates at random and using them to create embed-level open plate engraves. The second part of this investigation (evaluation of rotational discrepancy and vertical inconsistency) used open plate embed level impressions generated with the remaining thirty individualized plates to evaluate how well these materials recreated the patient's impressions. Within the bounds of the current investigation, vinylpolysiloxane had the highest degree of stiffness among the impression materials examined in comparison to polyether and vinylsiloxanether, as seen by its much greater rotational resistance to torquing. A rotational discrepancy was shown to be much lower in polyether open tray implant level impressions compared to vinylpolysiloxane and comparable to vinylsiloxane. In this investigation, the firmest impression medium was vinylpolysiloxane, followed by polyether and vinylsiloxanether for taking imprints of implants. Polyether material, however, was more precise than vinylpolysiloxane and vinylsiloxanether.

AN IN VITRO COMPARISON OF OVERALL FIT OF COBALT-CHROMIUM COPINGS CASTED CONVENTIONALLY FROM INLAY CASTING WAX, PATTERN RESIN &amp; 3D PRINTED RESIN EVALUATED BEFORE &amp; AFTER CERAMIC FIRING CYCLES

Aim: To compare the overall fit of cobalt-chromium copings casted conventionally from inlay casting wax, auto polymerizing pattern resin &amp; 3D printed resin evaluated before &amp; after ceramic firing cycles. Method: A stainless-steel master die assembly was fabricated which was used to fabricate the working models. 60 working dies (Group A Inlay Casting Wax n=20, Group B Pattern Resin n=20, Group C 3D Printed Resin n=20) simulating full crown preparations werestudied. The stainless-steel master die was duplicated using polyvinyl siloxane (PVS) elastomeric impression and poured in gypsum type IV die stone. Dieswere scanned using a digital scanner. 60 cobalt-chromium (Co-Cr) metal copings were fabricated using three different techniques: inlay casting wax, autopolymerising pattern resin&amp; 3D printed resin. Each die was fired with conventional PFM ceramic. A standardized weightwas used to exert uniform pressure on the elastomeric impression material while recording the intaglio surface of the crowns (copings) fabricated before and after ceramic firings. It was thenscanned aiding in STL File. The STL files were later overlapped and evaluated on their respective working die STL file using the software. The overall fit was measured by colour surface mapping software viz before &amp; after ceramic firing cycles. Results: The copings obtained by 3D printed resin technique revealed the best overall fit before and after ceramic firing cycles amongst the three fabrication techniques. Conclusion: 3D printed resin technique had the best overall fit before and after ceramic firing cycles followed by inlay casting wax technique and pattern resin technique.

Comparative evaluation of linear dimensional accuracy of impressions made with different elastomeric impression materials (Polyether and Polyvinyl siloxane) in angulated and parallel implants-An invitro study

To date no technique has been proven to guarantee a completely passive fit of implant supported prosthesis framework. Several clinical variables such as angulation of implants, impression material and technique used may affect the precision of impressions. Hence, this study is designed to evaluate and compare the dimensional accuracy of the resultant casts made from open tray implant level impressions with two different impression materials (polyvinyl siloxane and polyether) in parallel and angulated implants. The study consisted of two control groups; master model –1with parallel implants and master model –2 with angulated implants. From master model 1and master model 2, total 40 implant level open tray impressions were made using PVS and polyether impression material and impressions were poured to obtain 40 study casts. The resultant casts were divided into 4 groups (10 casts in each group), according to the impression material used (PVS or Polyether) and implant’s orientation (parallel or angulated) in the casts. All casts were evaluated for the positional accuracy of the implant by using four reference distances with the help of a profile projector. These measurements were compared to the measurements calculated on the master model, which served as a control. The variations of the mean distance values with respective control values within a group were analyzed with one samples’ t’ test at 0.05 significance level. Further the mean distance variations between the groups were analyzed with independent samples ‘t’ test to evaluate group mean variations.The impressions made in the presence of angulated implants were significantly less accurate than the ones made with parallel implants. Regarding impression material the tested polyether resulted advantageous over polivinylsiloxane impression material in terms of recording positional accuracy of implants.

Fabricating 2 piece closed hollow obturator with elastomeric impression material: An innovative dental technique

Maxillectomy defects are the most common results in oro-nasal communication, which leads to an expected change in speech tone, difficulty in mastication, and deglutition. These affect the quality of life of the patient and also impact them psychosocially in a long run. The most common management of maxillectomy patients for both complete and partial is by maxillary obturator prosthesis. To reduce the weight of the obturators various procedures of hollowing are present in literature. In this article, we will discuss an alternate and innovative laboratory technique for the fabrication of closed hollow obturator which will reduce the time of both dental technicians and clinicians.