Condensation Silicone Impression Material Research Articles

Evaluation of the Bond Strength of Universal Tray Adhesives on Silicone Impression Materials Using an Acrylic Tray

To evaluate the bond strength of two commercially available universal tray adhesives on polyvinylsiloxane addition silicone and condensation silicone impression materials to an autopolymerizing polymethyl methacrylate acrylic tray material. Sixty flat square specimens were fabricated from autopolymerizing polymethyl methacrylate tray material to which an eye hook was incorporated to serve as the point of attachment to a universal testing machine. A polyvinyl chloride (PVC) pipe of 15 mm diameter and 25 mm long was used to house the impression material, and a metal rod was inserted into two centered holes to provide retention that serves as the second point of attachment to the universal testing machine. The specimens were divided into 4 groups of 15 specimens each. The first and second groups of specimens were applied with Coltene and Zhermack universal tray adhesives and tested with addition silicone impression material. The third and fourth groups were coated with the above-mentioned adhesives, respectively, and tested with condensation silicone. Each specimen was then attached to the universal testing machine. The maximum force at which separation failure occurred was divided by the area of adhesion and recorded as the adhesive strength in MPa. A significant difference was observed between mean MPa values of Zhermack and Colten universal tray adhesives, where the F value of 1314.116 was found to be significant at 0.000 levels indicating that the Zhermack adhesive had higher MPa than Coltene adhesive. Impression material again indicated significant difference (F = 132.514; p = 0.000), where addition silicone had higher MPa value than condensation silicone. Also, the interaction between adhesive and impression material was found to be significant (F = 10.794; p = 0.002). The adhesive bond strength of Zhermack universal tray adhesive was higher compared to that of Coltene universal tray adhesive irrespective of the elastomeric impression material. It was also found that bond strength of Zhermack universal tray adhesive with addition silicone impression material was the highest and Coltene universal tray adhesive with condensation silicone impression material was the least of all the four groups. Tray adhesives need to be applied to the tray to obtain an accurate and consistent impression. If there is a separation of impression materials from the tray, it may results in a distorted impression leading to poor final restorations.

A Sinus Tract Following Prosthodontic Treatment with a Dental Implant: A Case Report

This article describes the cause of a sinus tract developed four years after implant-supported prosthodontic treatment. The sinus tract and pain appeared to be associated with an accidentally embedded piece of condensation silicone impression material. The residual material was removed by a simple surgical incision. Clinicians should be aware of the odds of this event and take it into consideration whenever there is a similar postoperative problem.

Comparison of double-phase impression technique in 1 step and 2 steps by evaluating dimensional stability and accuracy of condensation silicones

The diverse viscosities of silicone impression materials are suited for their use in various impression techniques, intended to improve the precision of the cast impression in the form of a plaster model. The purpose of this research is to determine the dimensional stability and accuracy of the double-phase impression technique in 1 step and 2 steps by using a condensation silicone impression material. This research was carried out by using a precise stainless-steel master model and an individual aluminum tray. Comparing the abutments of the master model and the abutments of the double-phase impression technique in 2 steps, showed that they are wider on average 81 µm, while the abutments from the double-phase impression technique in 1 step are on average 281 µm wider in diameter. After analyzing the results obtained in relation to the diameter of the abutments, it can be concluded that the double-phase impression technique in 2 steps is dimensionally more stable and accurate compared to the double-phase impression technique in 1 step. This study shows that dimensional stability and accuracy of impression materials also depend on the selection of appropriate impression technique and proper performance in order to obtain a high quality dental impression that will be the basis for an accurate fixed-prosthodontic fabrication. Keywords: silicone impression material, impression technique, fixed partial dentures, dimensional stability and accuracy

Comparative Analysis of Dimensional Accuracy of Two Types of Silicone Impression Materials: Optosil and Elite-HD

Statement of the Problem: Understanding about impression materials, their properties, uses and manipulation can guide operators towards having more successful restorations. Purpose: The aim of this in vitro study was to compare the accuracy of a condensation silicone impression material, Optosil, and an addition poly siloxane impression material, Elite-HD. Materials and Method: A laboratory model with two metallic dies was used to make impression. A horizontal notch on one of the two dies simulated an undercut. Ten impressions were made by each impression material by the putty-wash technique. After pouring impressions with velmix die stone, a total of 20 stone casts were made from both materials. Measurements of casts were compared with the master model. Statistical analyses were performed using t-test. Result: This results of this study showed that the height of die without undercut decreased in both groups. Also the height above the undercut decreased in both groups, which was more obvious in Elite-HD group than Optosil group. The distance between dies increased in both groups, with higher figures for Elite-HD. So, Optosil is a more accurate material for registering inter-abutment distance than Elite-HD. The diameter of die under the undercut decreased in Optosil group and was similar to the master model in Elite-HD. Statistical analysis showed significant differences between these two groups in the distance between abutments (p=0.001), the diameter of die under the undercut (p=0.014) and the height of die above undercut(p=0.057). Conclusion: Optosil is more accurate in registering inter-abutment distance than Elite-HD, so Optosil is preferred for fixed partial denture impressions. Since Elite-HD showed more accuracy in C measurements than Optosil, it is preferred for single crown impressions.

The Effect of Silver-Zinc Zeolite Incorporation on Some Properties of Condensation Silicone Impression Material

Background: elastomeric impression materials are indicated when a high degree of accuracy is required, due to their excellent properties like details reproduction, dimensional stability and tear strength but with main two disadvantages those are their hydrophilicity as well as the absence of antibacterial activity. This study aimed to evaluate the effect of incorporation of 0.5% wt Ag-Zn zeolite into condensation silicone through the following tests; setting time, dimensional stability, reproduction of details, wettability, and hardness . Materials and methods: one hundred specimens were constructed of condensation silicone, divided into two groups for the first 50 specimens one0.5% by wt Ag -Zn zeolite was added, keeping the other fifty specimens without addition. Then each group further subdivided into five subgroups according to the conducted test. The tests performed were; setting time, dimensional stability, reproduction of details, hardness and wettability. Results: A statistically non-significant effect on the setting time and reproduction of details tests was observed, combined with a highly significant increase of wettability of condensation silicone after incorporation of 0.5% wt Ag-Zn zeolite with non-significant increase of dimensional change of condensation silicone following incorporation of 0.5% wt Ag-Zn zeolite. Hardness test results shoed statistically significant increase following the addition of Ag-Zn zeolite. Conclusion: Ag-Zn zeolite incorporated into condensation silicone, improved wettability which determine the extent to which an impression material replicates the structures of the oral cavity and production of bubble-free gypsum die. It also showed a statistically significant increase in the hardness of condensation silicone impression material, and had no effect on setting time, reproduction of details and dimensional stability.

The Effect of Silver-Zinc Zeolite Incorporation on Some Properties of Condensation Silicone Impression Material

The Effect of Silver-Zinc Zeolite Incorporation on Some Properties of Condensation Silicone Impression Material

A revised technique for fabrication of hollow mandibular denture: A solution to severely resorbed residual ridge

Purpose: Prosthodontic rehabilitation of elderly patients with severely resorbed ridges is difficult due to compromised ridge height, increased inter-arch distance and altered insertion of associated jaw muscles. Planning dentures in such cases often require dentures that are lightweight to reduce the risk of further ridge resorption, which could otherwise complicate the situation. The purpose of the present technique is to fabricate a light weight lower denture by a revision of previously described technique in the literature. Materials and Methods: This article elucidates a simple technique for the fabrication of lightweight denture (hollow denture) in elderly patients with severely resorbed mandibular ridge. The minimum thickness of denture base acrylic resin for structural durability is ensured by a wax shim of 2 mm. The adequate hollow space indenture for optimal weight reduction is created by condensation silicone impression material. Conclusion: Condensation silicone putty material can be successfully used as a spacer for hollow dentures to combat severe ridge resorption.

A Comparative Study to Determine the Wettability and Castability of Different Elastomeric Impression Materials

The aim of this study was to determine the wettability of different hydrophilic and hydrophobic elastomeric impression materials and the gypsum castability. The wettability was evaluated by determining the contact angles of different elastomeric impression materials. The contact angle was determined by placing a drop of aqueous solution of calcium sulfate dihydrate on the flat surface of impression material and specimens were measured using a profile projector. Gypsum castability was determined by counting the number of voids formed in the die stone cast made from the impressions of a aluminum die. The voids were counted using an diopter magnifying lens. Polyether, different viscosities of polyvinyl siloxane, and condensation silicone impression materials exhibited low contact angle values and least number of voids in the die stone cast when compared with polysulfide impression material. There was significant correlation between the contact angle and voids formed in the die stone casts when fabricating die stone casts from various elastomeric impression material impressions. Accurate reproduction of prepared tooth or edentulous arch is of clinical importance in the fabrication of a fixed or removable prosthesis. Inaccuracies in the replication processes will ultimately have an adverse effect on the fit and adaptation of final restoration. The interaction is determined in part by hydrophilic and hydrophobic nature of the elastomeric impression material. Inadequate wetting of an impression results in voids in the stone casts.

The effect of disinfection by spray atomization on dimensional accuracy of condensation silicone impressions.

Background and aims The condensation silicone impression materials are available, but there is little knowledge of their accuracy after disinfection. The objective of this study was to evaluate the effect of the disinfection by spray atomization on dimensional accuracy of condensation silicone impressions. Materials and methods Impressions were made on a stainless steel master model containing a simulated two complete crown preparation with an edentulous space interposed using Spidex® and Rapid® impression materials. 44 impressions were made with each material, of which 16 were disinfected with 5.25% sodium hypochlorite, 16 were disinfected with 10% iodophor and 12 were not disinfected. Three dimensional measurements of working casts, including interpreparation distance, height, and diameter, were calculated using a measuring microscope graduated at 0.001 mm. Dimensional changes (mm) between the disinfected and non-disinfected working casts were compared. One-way analysis of variance (ANOVA) was employed to analyze the data (α=0.05). Results Disinfection of each condensation silicone material by spraying atomization with two different disinfectant material resulted in significant change in interpreparation distance (p<0.05). Changes in height and diameter were only significant in Spidex® impressions (p<0.05). Conclusion Significant changes in the mean dimensions were seen as a result of disinfection by spraying; however, the dimensional changes do not seem great enough to cause critical positional distortion of teeth when fixed partial denture restorations are made.

Intrapulpal Heat Generation during Provisionalization: Effect of Desensitizer and Matrix Type

This study investigated the effect of different matrices and application of a desensitizer on pulpal temperature rise during direct provisionalization. The apical third of a second premolar was resected and pulpal tissue was removed. Silicone heat-conducting medium was injected, and a J-type thermocouple was inserted into the pulp chamber and sealed. The tooth was embedded in acrylic resin with its cervical line 1 mm higher than the base. Addition and condensation silicone impression materials were mixed and placed inside plastic molds. Impressions were taken before tooth preparation. The tooth was then prepared with a 1.5-mm shoulder finish line. The experimental model was kept in a 36 degrees C water bath. Four provisional materials were applied in sequence onto the prepared tooth using matrices. Each provisional resin was used in combination with each matrix (n = 12). Then a dentin desensitizer was coated on the prepared tooth and provisionalizations were made in the same manner. The thermocouple was connected to the data-logger. During setting of the resins, pulp temperatures were recorded and transferred to the computer. Measurements were conducted for each test group by calculating the temperature rise as the difference between the start and highest temperature reading. The type of the silicone matrix used and the use of desensitizer did not affect the intrapulpal heat generation during direct provisionalization. Application of a desensitizer and different type of matrix seems to be noneffective on intrapulpal heat rise, although the type of provisional material used may be effective.

Adhesive properties of several impression material systems: Part I

The tensile adhesive bond strength of five impression adhesive systems was studied: polysulfide, polyether, polyvinylsiloxane, condensation silicone impression, and polyvinylsiloxane putty adhesive systems. Results showed no significant difference in adhesive bond strength to autopolymerizing acrylic resin between the former four impression materials studied. Polyether and medium-viscosity polyvinylsiloxane demonstrated significantly higher adhesive bond strength to polystyrene than either polysulfide or condensation silicone. The medium-viscosity polyvinylsiloxane impression material showed significantly higher adhesive bond strength to polystyrene than autopolymerizing acrylic resin whereas polysulfide and condensation silicone impression materials adhered significantly better to autopolymerizing acrylic resin than polystyrene. The polyvinylsiloxane putty did not adhere to its impression adhesive. Variation of the speed of tensile testing between 5 to 20 inches per minutes did not affect the adhesive bond strength of a polysulfide impression material.

Use of an elastomeric material to improve the occlusal seat and marginal seal of cast restorations

A method to improve the fit of castings by the use of a light-bodied condensation silicone impression material was tested. Eighteen-full coverage castings were made on individual resin dies and divided into two groups. The experimental group was adjusted internally to a uniform precementation space by using the silicone impression material as a disclosing agent for binding of the castings on the axial or occlusal walls. Measurements of marginal fit were made with a light microscope using a filar eyepiece both externally and internally by sectioning after cementation with a zinc phosphate cement. Results demonstrated a significant improvement in marginal seal and occlusal seating in the experimental group compared with the control group. The condensation silicone material proved to be an appropriate research tool for nondestructive, three-dimensional evaluation of the postcementation space and offers a new method of evaluation of cement thickness because seating was found to be not significantly different from that with zinc phosphate cement.

The future of silicon technology : Glen R Madland. Solid St. Technol. p. 91 (August 1977)

A method to improve the fit of castings by the use of a light-bodied condensation silicone impression material was tested. Eighteen-full coverage castings were made on individual resin dies and divided into two groups. The experimental group was adjusted internally to a uniform precementation space by using the silicone impression material as a disclosing agent for binding of the castings on the axial or occlusal walls. Measurements of marginal fit were made with a light microscope using a filar eyepiece both externally and internally by sectioning after cementation with a zinc phosphate cement. Results demonstrated a significant improvement in marginal seal and occlusal seating in the experimental group compared with the control group. The condensation silicone material proved to be an appropriate research tool for nondestructive, three-dimensional evaluation of the postcementation space and offers a new method of evaluation of cement thickness because seating was found to be not significantly different from that with zinc phosphate cement.