A Comparative Evaluation of Dimensional Accuracy and Surface Detail Reproduction for Polyvinyl Siloxane and Vinyl Siloxane Ether under Dry and Moist Conditions- An In-vitro Study

Author(s):  
Amit Baban Pokharkar ◽  
Umesh Gopal Palekar ◽  
Veena Saraf ◽  
Deepak Machindra Vikhe ◽  
Shefali Sevakram Bhiwapurkar ◽  
...  

Introduction: The conventional impression procedure plays a major role in prosthodontics inspite of advancement in intra- oral scanning devices and 3D imaging procedures. Dimensional accuracy and surface detail reproduction are important for recording an impression. Aim: The study evaluated and compared the dimensional accuracy and surface detail reproduction of Polyvinyl Siloxane (PVS) and vinyl siloxane ether impression materials when used under dry and moist conditions. Materials and Methods: An in-vitro study was conducted in the Department of Prosthodontics, Rural Dental College, Pravara Institute of Medical Sciences, Loni, Ahmednagar, Maharashtra, India, for a period of two years from October 2018 to September 2020. A total of 60 impressions were made with PVS (Group A) and vinyl siloxane ether (Group B) under dry (A1, B1) and moist (A2, B2) conditions of stainless steel dies which had lines engraved on superior surface of the die. Using a Harloc’s Tool maker’s microscope, dimensional accuracy was measured by comparing the width of line Y in each impression. Surface detail reproduction was evaluated by American Dental Association (ADA) specification no. 19 where it stated continuous replication of at least any two lines out of the three lines inscribed on the die. Data analysis processing was performed in the SYSTAT version 12 (made by Crane’s software, Bangalore). Student’s unpaired t-test and Chi-square test were performed to determine statistical difference between PVS and vinyl siloxane ether where the level of significance was set at 5% and 1%. Results: The mean dimensional change and SD values for PVS under dry condition ranged from 21.93±2.46 to 22.40±2.89 (in mm). The mean dimensional change and SD values for PVS under moist condition ranged from 22.87±3.20 to 23.33±3.42. The mean dimensional change and SD values for vinyl siloxane ether under dry condition ranged from 21.93±3.61 to 24.73±5.20. The mean dimensional change and SD values for vinyl siloxane ether under moist condition ranged from 21.93±4.48 to 22.87±4.15. No statistical difference was found under dry and moist conditions within 2 hours and after 24 hours for both the materials. Conclusion: The study revealed no significant difference between dimensional accuracy and surface detail reproduction for PVS and vinyl siloxane ether. Both the materials can reproduce the details under dry and moist conditions satisfactorily and remained dimensionally stable till 24 hours after impression making.

2021 ◽  
Vol 13 (2) ◽  
pp. 47-51
Author(s):  
Samaneh Abbasi ◽  
Soodabe Ebrahimi ◽  
Arash Shisheian ◽  
Maryam Farhadian

Background: Acrylic resin teeth wear resistance has an important role in the denture longevity. This study aimed to clarify the effect of glaze coating on wear resistance of three types of artificial acrylic teeth. Methods: In this in vitro study, the wear resistance rate of three of acrylic denture teeth (GENIUS, STON and CLASSIC) was compared with Ivoclar teeth (n=25/group). The wear resistance was measured by estimating the weight loss in pre and post removing glaze coating, following 5000 cycles in the chewing simulator device. Data analysis was made using paired t test, one-way ANOVA and Tukey’s post hoc test. Results: ANOVA test showed that there was no significant difference between the mean amount of wear of GENIUS, CLASSIC, STON and IVOCLAR teeth in the first stage (P <0.061), but this difference was significant (P <0.001) in the second stage. The result of Tukey post hoc test showed that wear rates of GENIUS were significantly lower than other groups (P<0.001). Comparison between the mean wear rates of each dental group at the first and second stages showed a significant difference between average teeth wear resistance of CLASSIC, STON and IVOCLAR in the first and second stages (P <0.001). Conclusions: In conclusion, the teeth wear resistance of STON and CLASSIC were similar to IVOCLAR. Also, after removing the glaze coating, the teeth wear resistance decreased in all groups but was not statistically significant for group GENIUS.


2021 ◽  
Vol 11 (4) ◽  
pp. 306-312
Author(s):  
Dalia M. Abouelmagd ◽  
Hanan K. Abouelseoud

Objectives: This study aimed to compare the microshear bond strength (µSBS) of self-adhesive flowable composite and conventional bonded flowable composite to sound and caries affected dentin. Materials and Methods: In this in vitro study, a total of freshly extracted 40 human molar teeth were used. The occlusal surface was sectioned to expose dentin for µSBS test. The teeth were randomly divided into 2 groups according to the type of flowable composite used into two groups (n=20): group A: self- adhesive flowable composite (Vertise flow), group B: Filtek Z350-XT flowable composite and one-step self-etch adhesive Adper Easy One. A plastic cylindrical mold was used to construct resin composite cylinders (0.8mm diameter x 1mm length) on the sound and caries affected exposed dentin and filled with flowable composite restorative materials according to manufacturer’s instructions. The samples were then immersed in distilled water at 37°C for 24 hours, and underwent µSBS test at a crosshead speed of 0.5 mm/min. Data were analyzed using Student's t-test to compare between the two materials as well as to compare between sound and caries affected dentin. Results: The mean values of µSBS of Filtek Z-350XT to sound and caries affected were 26.6 and 26.7 MPa respectively. The mean µSBS of Vertise Flow to sound and affected were 13.2 and 17.9 MPa respectively. With sound dentin FiltekZ-350XT showed statistically significant higher µSBS than Vertise flow. With caries affected dentin, there was no statistically significant difference between the two materials. There was no statistically significant difference between µSBS of sound and caries affected dentin within each material. The significance level was set at P ≤ 0.05. Conclusions: Within the limitations of this study, the conventional flowable composite yielded the highest µSBS to sound dentin. There was no statistical significant difference in µSBS of self-adhesive and conventional flowable to caries affected dentin. Key words: Composite Resins; Dentin; microshear.


2018 ◽  
Vol 1 (2) ◽  
pp. 67-74
Author(s):  
Anisha Pandey ◽  
S.R.B. Mathema ◽  
S.K. Maharjan

Introduction: Dimensional accuracy of cast obtained after making impressions is crucial factor for the quality of fixed prosthodontic treatment. The impression technique with different thickness of putty wash material is critical factor affecting this accuracy. There is much discussion in the dental literature concerning the effect of this impression technique on the accuracy of cast restorations. Materials and methods: This in-vitro study was carried out in 60 impression made from master model with Polyvinyl siloxane impressions material using single step putty- wash technique and two step putty-wash technique with varying spacer thickness (0.5mm, 1mm, 1.5 mm). It was further divided into four groups. Group I: Single step putty-wash impression technique, Group II: Two step putty-wash impression technique with 0.5mm spacer, Group III: Two step putty-wash impression technique with 1mm spacer, Group IV: Two step putty-wash impression technique with 1.5mm spacer. Each group consists of 15 impressions. Casts were poured using type IV dental stone after 1 hour. After 24 hour the die of each cast was scanned using CAD/CAM digital scanner and measured mesiodistally, facio-lingually, height (cervico-occlusally), interabutment or interdie distances. The data were recorded and statically analyzed. Results: The highest mean values of mesio-distal, bucco-lingual, cervico-occlusal distances were shown by Group I, whereas the inter-die distance showed equal mean value in Group I, II and III. With the increase in the spacer thickness, the mean value also increases in mesio-distal distance. The mean measurement of bucco-lingual dimension was highest when spacer thickness was 0.5mm and it declined with the increase in spacer thickness. The spacer thickness had no effect on cervico-occlusal and inter-die dimensions. Conclusions: Within the limitations of the study, accuracy of cast obtained from single step putty-wash technique was more accurate than two step putty-wash technique. In two step putty-wash technique, 1.5 mm thickness of spacer showed more accurate cast in comparison to 0.5mm and 1mm.


Author(s):  
Aparna Dwivedi ◽  
Kavita Maru ◽  
Aakash Sharma

Introduction. The interocclusal registration materials record the occlusal relationship between the natural and /or artificial teeth for planning an occlusal rehabilitation in removable and fixed partial dentures. Aim and objectives. The aim of this in vitro study was to evaluate and compare the accuracy and the three dimensional stability offered by three different types of interocclusal recording materials at storage time intervals of 1 hour and 24 hours. Methods. Three commercially available interocclusal recording materials were used - Group I - Polyether bite registration paste (Ramitec), Group II- Polyvinylsiloxane bite registration material (Imprint), Group III- Bite registration wax (Maarc).The test was carried out using an epoxy resin model. A total of 30 samples were made with each group consisting of ten samples. Three dimensional measurements were carried out by using 3D-Coordinate measuring machine (CMM) at time intervals of 0-1 hour and 0-24 hours in X, Y and Z- axis.   Results. Twelve readings were obtained for three axes (4 readings for each sample at 1 axis) and the averages of these four values were noted for a particular axis (X/Y/Z). Statistical analysis was performed using analysis of variance (ANOVA) for comparison among the groups and then Tukey’s honestly significant difference (HSD) tests was performed for comparison among groups at the 0.05 level of significance. Conclusion. Polyvinylsiloxane was dimensionally the most stable material followed by polyether and finally bite registration wax. Dimensional accuracy and stability is influenced by both “material” and “time” factors.


Author(s):  
Rathika Rai ◽  
M. A. Easwaran ◽  
K. T. Dhivya

Aim: To evaluate the surface detail reproduction of dental stone this is immersed in different disinfectant solution and studied under stereomicroscope. Methodology: Total number of 30 specimens of dental stone (Type III) were made with measurements of 1.5cm diameter and 1cm height .This samples are divided in to 3 groups group A,B,C. were A is immersed in Distilled water which was taken as control group ;B is immersed in 2% Glutaraldehyde and C is immersed in 5%sodium hypochlorite. Each specimen were immersed in the disinfectant solution for 15 minutes and dried under room temperature for 24 hrs. After 24 hrs each specimens are studied under stereomicroscope for surface details. Result: The results showed no significant difference in the surface irregularities and porosities for a group 1 and group 2 except group 3 which showed significant increase in the porosities, surface irregularities and erosions after disinfection with 5% NaHOCl by immersion method. Conclusion: The surface detail reproduction capacity of die stone was adversely affected when 5% Sodium hypochlorite was used as disinfectant solution when compare d to control group and 2% Glutaraldehyde


2021 ◽  
Vol 11 (2) ◽  
pp. 857
Author(s):  
Keunbada Son ◽  
Kyu-Bok Lee

The purpose of this in vitro study was to evaluate marginal and internal fits of ceramic crowns fabricated with chairside computer-aided design and manufacturing (CAD/CAM) systems. An experimental model based on ISO 12836:2015 was digitally scanned with different intraoral scanners (Omnicam (CEREC), EZIS PO (DDS), and CS3500 (Carestream)). Ceramic crowns were fabricated using the CAD/CAM process recommended by each system (CEREC, EZIS, and Carestream systems; N = 15). The 3-dimensional (3D) marginal and internal fit of each ceramic crown was measured using a 3D inspection software (Geomagic control X). Differences among the systems and various measurements were evaluated using the Kruskal–Wallis test. Statistically significant differences were validated using pairwise comparisons (α = 0.05). Occlusal gaps in the CEREC, EZIS, and Carestream groups were 113.0, 161.3, and 438.2 µm, respectively (p < 0.001). The axial gaps were 83.4, 78.0, and 107.9 µm, respectively. The marginal gaps were 77.8, 99.3, and 60.6 µm, respectively, and the whole gaps were 85.9, 107.3, and 214.0 µm, respectively. Significant differences were observed with the EZIS system compared with the other two systems in terms of the marginal gap sizes. The CEREC system showed no significant differences among the four measured regions. However, the EZIS and Carestream systems did show a statistically significant difference (p < 0.05). All three systems were judged to be capable of fabricating clinically acceptable prostheses, because the marginal gap, which is the most important factor in the marginal fit of prostheses, was recorded to be below 100 µm in all three systems.


2021 ◽  
Vol 125 (1) ◽  
pp. 103-110 ◽  
Author(s):  
Norbert Nestler ◽  
Christian Wesemann ◽  
Benedikt C. Spies ◽  
Florian Beuer ◽  
Axel Bumann

2018 ◽  
Vol 6 (02/03) ◽  
pp. 106-111
Author(s):  
Ramandeep Kaur ◽  
Manjit Kumar ◽  
Shailesh Jain ◽  
Neha Jindal

Abstract Statement of Problem The adhesion of impression material to impression tray is very important. Tray adhesive plays a major role in making accurate impression. Although manufactures recommend the use of particular tray adhesives, comparison of their affective adhesiveness has not been reported. The effect of use of tray adhesives on dimensional accuracy of dies has not been established. Purpose The aim of this study was to compare the dimensional accuracy of dies using different tray adhesives at different time intervals. Materials and Methods First part of study comprised 120 samples in six groups with 20 samples in each group. First group comprised samples with no tray adhesive, and in other five groups, different types of tray adhesives were applied. The dies obtained were evaluated for upper diameter, lower diameter, and occlusogingival height. In the second part, there were a total of 125 samples in five groups with 25 samples in each group. Five different types of tray adhesive were applied for five different time intervals 5, 10, 15, 20, and 25 minutes, respectively. The specimens were tested in tensile mode for its debonding force at a crosshead speed of 5 mm/min, until separation failure occurred. Results Significant difference was seen for upper and lower diameters when compared with the group without any tray adhesive. The maximum bond strength was found in the group in which tray adhesive was applied for 20 minutes.


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