The Assessment of Time and Storage Environment Effects on Dimensional Changes of Two Types of Acrylic Resin Post Patterns GC and Reliance

Author(s):  
Amin Khaleghi ◽  
Malihe Taghizadeh ◽  
Mohsen Hormozi

Introduction: The purpose of this study was to investigate and compare the dimensional changes in the acrylic patterns that were stored in the different times and conditions of storage. Materials& Methods: In this experimental study The sample number was 28 in 4 groups. The mixed paste of acrylic samples were placed inside a metal mold and after setting time with the slightest of deformations it was removed. Using this method 28 samples were prepared for each material. The diameters of samples were then measured immediately using a digital caliper with a precision of 0.01 mm. The samples were then divided into four quadruple groups and stored at 22° C room temperature, 22° Cat water, Dry 4° C environment and 4° C water. The dimensions of the four groups were measured at intervals of 1, 8, 24, and 48 hours after polymerization and being removed from the metal molds. The ANOVA test was used for data analysis (p value = 0.05). Results: The findings of the current study showed that the dimensional changes of Duralay and GC acrylic resins at both 4 and 22° C in dry and water environments are decreasing over time (p value < 0.001). This study indicated that the contraction rate of two types of acrylic resins, Duralay and GC, at two temperatures of 4 and 22° C, and dry and humid conditions and at various times were not different. Conclusion: Dimensional changes in of the two types of acrylic resin, Duralay and GC, During the lapse, the procedure is going to be decreased but have not seen any statistical difference between these type of acrylic resin in environment storage.

2015 ◽  
Vol 9 (1) ◽  
pp. 87-90
Author(s):  
Mahmoud Sabouhi ◽  
Saied Nosouhian ◽  
Mansour Dakhilalian ◽  
Amin Davoudi ◽  
Ramin Mehrad

Introduction : Post and core are needed to regain retentions and functions after endodontic therapies. Also, risk of cross contamination from dental prosthesis is so high. The aim of this study was to compare dimensional changes of acrylic resin patterns (ARP) in three different storing environments. Materials and methods : conventional root canal therapy was done on one first premolar tooth and the canal filled with Guttapercha. 2/3 of the filling was expelled and 30 direct APRs were prepared by Duralay. The samples were divided into 3 groups based on storing environments: water, NaOCl 5% and air. Finally dimensional changes in coronoapical length (CAL), coronal (CD) and apical diameter (AD) of APRs were measured in 7 consecutive times (immediately after polymerization, 1, 2, 4, 8, 24, 48 hours later). All the data were analyzed by Paired T-test and Duncon test using SPSS software ver.13 at significant level of 0.05. Results : After 24 hours, the ARPs, which were stored in air, contracted 0.07, 0.06 and 0.12 mm in AD, CD and CAL; the ARPs, which were stored in water, showed 0.03, 0.06 and 0.12 mm decrease in AD, CD and CAL; But the ARPs, which were stored in NaOCl 5%, showed significant expansion in AD, CD and CAL (0.03, 0.06 and 0.10 mm) (all P values < 0.01). Conclusion : It is better not to use NaOCl for disinfecting; also the best time for storing APRs is 8 hours for water and 2 hours for air environments after setting time.


2014 ◽  
Vol 1025-1026 ◽  
pp. 797-802 ◽  
Author(s):  
Tassanaporn Saen-Isara ◽  
Surachai Dechkunakorn ◽  
Niwat Anuwongnukroh ◽  
Toemsak Srikhirin ◽  
Siriporn Tanodekaew

Objective: To evaluate the effects of interchanging the liquid components of two commercially available orthodontic auto-polymerizing acrylic resin in their flexural properties, clarity and setting time


Author(s):  
Saeed Noorollahian ◽  
Farinaz Shirban ◽  
Vahid Mojiri

Introduction: The daily use of orthodontic removable plates can interfere with the self-cleansing function of the mouth. Although various techniques have been proposed for cleaning removable orthodontic appliances, there is no consensus on the use of a safe method that preserves the physical properties of the appliance. This study aimed to investigate the effect of using hydrochloric acid (10%, for removal of mineral deposits) and sodium hypochlorite (5.25%, to remove organic matter and discolorations) on surface hardness and roughness of self-cure orthodontic acrylic resins. Materials & Methods: This cross-sectional laboratory study was conducted in the fall of 2017 at Isfahan University of Medical science and Isfahan University of Technology. In this study two orthodontic acrylic resins (Orthocryl® and Acropars®) were used. Eighty samples (12×10×3 mm) from each one were fabricated and divided into four groups (n = 20). Group 1: 15 minutes immersion in household cleaner liquid (Hydrochloric acid, 10%) followed by15 minutes immersion in household bleach liquid (Sodium Hypochlorite, 5.25%). In group 2, immersions were repeated just like group two times and in group 3, were done three times. Group 4 was as control and had no immersion. The surface hardness and roughness of samples were measured. Data were analyzed with Two Way ANOVA and the significance level was set at 0.05. Results: The number of immersion procedures did not significantly affect the surface hardness (p value = 0.958) and surface roughness (p value = 0.657) in the different study groups. There was no significant difference in the surface hardness between the two acrylic resin brands (p value = 0.077); however, Acropars acrylic resin samples exhibited significantly higher surface roughness compared to the Orthocryl acrylic resin samples(p value < 0.001). Conclusion: 15 minutes of immersion in 10% HCl, followed by 15 minutes of immersion in 5.25% NaOCl and repetition of the procedure three times did not significantly affect the surface hardness and roughness of self-cured acrylic resins.


2015 ◽  
Vol 9 (1) ◽  
pp. 87-90
Author(s):  
Saied Nosouhian ◽  
Mahmoud Sabouhi ◽  
Mansour Dakhilalian ◽  
Amin Davoudi ◽  
Ramin Mehrad

2018 ◽  
Vol 47 (1) ◽  
pp. 51-56
Author(s):  
Natália Pereira de OLIVEIRA ◽  
Renata Pilli JÓIAS ◽  
Rodnei Dennis ROSSONI ◽  
Renato Morales JÓIAS

Abstract Introduction The most used material for the preparation of the baseplates is the acrylic resin, but it can present distortions. Objective To evaluate preparation technique, region and storage time that presents less maladaptation of the base when made with self-cured acrylic resin. Material and method Models were created in gypsum type III simulating edentulous maxilla, as divided into 3 groups (n = 10): GC (control group) thermopolymerizable acrylic resin; G1 - manual adaptation technique and G2 - drip technique. For the measurements, silicone by condensation of light consistency that was interposed between base and model was used. With a hydraulic press, 50 kg pressure was applied leading the base of the model. The obtained mold was measured in the palate, canine and molar regions with a digital caliper at the following times: immediately after the base polymerization, at 24, 48, 72, 96 hours and one week. The results were submitted to statistical analysis. Result G1 presented maladaptation of 0.43 mm ± 0.10, while G2 obtained 0.39 mm ± 0.11. The lowest maladaptation occurred in the CG. The palate region presented greater maladaptation (0.52 ± 0.07) and the canine region, the lowest (CD = 0.27 mm ± 0.07 and CE = 0.27 ± 0.09); There was no statistically significant difference for storage times. Conclusion G2 presented lower values than G1, with no statistically significant difference. The palate region presented greater maladaptation, followed by molars and canines. The bases continued to maladaptation the model after the immediate polymerization, with no statistically significant difference.


2008 ◽  
Vol 19 (3) ◽  
pp. 204-208 ◽  
Author(s):  
Ana Carolina Miéssi ◽  
Marcelo Coelho Goiato ◽  
Daniela Micheline dos Santos ◽  
Stefan Fiúza de Carvalho Dekon ◽  
Ricardo Coelho Okida

The aim of this study was to evaluate the dimensional changes of denture bases made from different resins after different storage periods. For this purpose, 25 sets of plaster models/resin bases were prepared using 4 acrylic resins submitted to two types of polymerization: 1- QC-20 submitted to polymerization by microwave energy; 2- QC-20 submitted to polymerization by water hot bath; 3- Vipi Cril submitted to polymerization by water hot bath; 4- Vipi Wave submitted to polymerization by microwave energy; and 5- Onda Cryl submitted to polymerization by microwave energy. After polymerization, the specimens were sectioned for accuracy readings using a comparison microscope. Readings were taken at 3 points: the crests of the right (A) and left (B) ridges, and the median region of the palate, in 4 different periods. The data obtained were submitted to two-way ANOVA and Tukey's test at 5% significance level. The greatest distortions were found in the posterior palatal region of the base (M), with statistically significant difference (p<0.05) for the studied resins. All acrylic resins presented dimensional changes and the storage period influenced these alterations.


2008 ◽  
Vol 02 (03) ◽  
pp. 191-197 ◽  
Author(s):  
Suleyman Hakan Tuna ◽  
Filiz Keyf ◽  
Hasan Onder Gumus ◽  
Cengiz Uzun

ABSTRACTObjectives: The absorption of water by acrylic resins is a phenomenon of considerable importance since it is accompanied by dimensional changes, a further undesirable effect of absorbed water in acrylic resins to reduce the tensile strength of the material. Solubility is also an important property because it represents the mass of soluble materials from the polymers.Methods: Ten acrylic resin-based materials were evaluated: two heat cure acrylic resins (De Trey QC-20, Meliodent Heat Cure) and eight self cure acrylic resins (Meliodent Cold, Akrileks, Akribel, Akribel Transparent, Vertex Trayplast, Formatray, Dentalon Plus, Palavit G). To evaluate water sorption and water solubility, thirty square-shaped specimens (20×20×1.5 mm) were fabricated from the wax specimens. One way ANOVA test, Tukey test and Pearson correlation coefficient performed for data.Results: Water sorption mean values varied from 11.33±0.33 to 30.46±0.55 μg/mm3. Water solubility mean values varied from -0.05±0.23 to 3.69±0.12 �g/mm3. There was statistically significant difference between mean values of the materials (P<.05). There was no linear correlation between sorption and solubility values.Conclusions: The results of the water sorption and water solubility values of both self-cured and heat-cured acrylic resins were in accordance with the ISO specification. No correlation found between water sorption and water solubility values. (Eur J Dent 2008;2:191-197)


Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1234
Author(s):  
António Sérgio Silva ◽  
Aurora Carvalho ◽  
Pedro Barreiros ◽  
Juliana de Sá ◽  
Carlos Aroso ◽  
...  

Thermal and self-curing acrylic resins are frequently and versatilely used in dental medicine since they are biocompatible, have no flavor or odor, have satisfactory thermal qualities and polishing capacity, and are easy and fast. Thus, given their widespread use, their fracture resistance behavior is especially important. In this research work, we comparatively analyzed the fracture resistance capacity of thermo and self-curing acrylic resins in vitro. Materials and Methods: Five prosthesis bases were created for each of the following acrylic resins: Lucitone®, ProBase®, and Megacryl®, which were submitted to different forces through the use of the CS® Dental Testing Machine, usually mobilized in the context of fatigue tests. To this end, a point was defined in the center of the anterior edge of the aforementioned acrylic resin bases, for which the peak tended until a fracture occurred. Thermosetting resins were, on average, more resistant to fracture than self-curable resins, although the difference was not statistically significant. The thermosetting resins of the Lucitone® and Probase® brands demonstrated behavior that was more resistant to fracture than the self-curing homologues, although the difference was not statistically significant. Thermosetting resins tended to be, on average, more resistant to fracture and exhibited the maximum values for impact strength, compressive strength, tensile strength, hardness, and dimensional accuracy than self-curing resins, regardless of brand.


2006 ◽  
Vol 17 (2) ◽  
pp. 122-125 ◽  
Author(s):  
Carolina B. Meloto ◽  
Laís R. Silva-Concílio ◽  
Cristiane Machado ◽  
Margarete C. Ribeiro ◽  
Fábio A. Joia ◽  
...  

This study evaluated water sorption in heat-polymerized acrylic resins processed in monomaxillary flasks by water bath and in bimaxillary flasks by microwave energy and water bath. Fifty heat-polymerized acrylic resin specimens were fabricated according to the 12th specification of the American Dental Association and assigned to 3 groups: group 1 was processed by water bath in monomaxillary metallic flask; group 2 was processed by microwave energy in bimaxillary PVC flask; and group 3 was processed by water bath in bimaxillary metallic flask. Specimens were submitted to water sorption test, means were calculated and analyzed statistically by Student's t-test. Means (in g/cm³) were: group 1 - 0.024085, group 2 - 0.025312 and group 3 - 0.022098. Microwave energy processing and the amount of stone and resin used in the bimaxillary PVC flask did not influence water sorption; specimens processed in bimaxillary metallic flask by water bath presented lower water sorption means, suggesting an inadequate polymerization of the acrylic resin mass.


2013 ◽  
Vol 18 (6) ◽  
pp. 26-30 ◽  
Author(s):  
Glaucio Serra ◽  
Liliane Siqueira de Morais ◽  
Carlos Nelson Elias

INTRODUCTION: The finishing and polishing phases are essential to improve smoothness and shining on the surface of acrylic resins used to make removable orthodontic appliances. A good surface finishing reduces roughness, which facilitates hygiene, prevents staining and provides greater comfort to the patients. OBJECTIVE: The aim of this paper was to analyze the changes on surface morphology of acrylic resins during finishing and polishing phases. METHODS: Thirty discs (10 mm in diameter and 5 mm in length) were made with acrylic resin and randomly divided into ten groups. The control group did not receive any treatment while the other groups received gradual finishing and polishing. The last group received the entire finishing and polishing procedures. Surface morphology was qualitatively analyzed through scanning electron microscopy and quantitatively analyzed through a laser profilometer test. RESULTS: The acrylic resin surfaces without treatment showed bubbles which were not observed in the subsequent phases. Wearing out with multilaminated burs, finishing with wood sandpaper and finishing with water sandpaper resulted in surfaces with decreasing irregularities. The surfaces that were polished with pumice and with low abrasive liquids showed high superficial smoothness. CONCLUSION: Highly smooth acrylic resin surfaces can be obtained after mechanical finishing and polishing performed with multilaminated burs, wood sandpaper, water sandpaper, pumice and low abrasive liquids.


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