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Article
Effect of Relining Curing Methods on Some Properties of Acrylic Resin Denture Base (Part II)

Author: Nadira A Hatim
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2013 Volume: 13 Issue: 2 Pages: 211-220
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: To investigate the effect of relining by using two curing methods (water bath, or microwave) on some properties ( surface hardness, color property, residual monomer, and porosity) of relined acrylic resin denture base. Materials and methods: The study was done by preparing 320 samples, divided into two parts, the first part involved studying surface hardness, color property, residual monomer, and porosity of samples representing a denture base cured by water bath curing method, and the samples of second part cured by microwave curing method, then the effect of relining by the two curing methods (water bath, and microwave) were evaluated. Samples with dimensions of 30×15×3 ± 0.03mm for the indentation hardness test, 45×10×2.5mm for the color property test, 20×20×3mm for residual monomer test were prepared in this study. Analysis of variance (ANOVA) and Duncan's multiple range tests were used for statistical analysis. Results: surface hardness of denture base cured by microwave was significantly higher (at P=0.05) than denture base cured by water bath, all the relined samples has sig-nificant higher absorbance, and showed that the elusion of monomer was higher at the 1st day. Conclu-sions: Surface hardness, color property and residual monomer of the acrylic resin denture base were affected by relining. Microwave curing method gave better mechanical, and physical properties of the relined acrylic resin denture base, the amount of residual monomer was less in the microwave curing method. Both curing methods gave samples free from porosities.


Article
Acrylic denture base repair (part I): Estimations of repair space, profile designs, and residual monomer calibration curve on strength of denture base.

Authors: Nadira A Hatim --- Mohammed M Sadoon
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2006 Volume: 6 Issue: 3 Pages: S107-S113
Publisher: Mosul University جامعة الموصل

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Abstract

To estimate the best profile design used for repair at the fractured area, the suitable space to be left between the two fracture pieces, and to determine the percentage of residual monomer calibration curve of heat cured acrylic resin polymerized by water bath. Material and methods: Forty five samples of heat cured acrylic denture base resin were prepared, and repaired by water bath with different profile designs, and different space distances at fractured area, the samples were tested to measure transverse strength. In addition to five samples prepared for determination of the light absorbency of aqueous solution by spectrophotometer. Analysis of variance (ANOVA), and Duncan’s multiple range test were used for statistical analysis. Results: showed that there is no significant difference between different profile designs, and no significant differences between repaired samples with 2 and 3 mm space at fracture area. The absorbency of aqueous solution at 0.125–0.005 mg/ml concentration is helpful for this study. Conclusion Repaired specimens showed less transverse strength than control group.Repaired samples with 2 mm repair space and 3 mm repair space were significantly higher than that of 1mm repair space.


Article
Influence of Heating Rates and Residual Monomer on Dimensional Changes of Acrylic Resin Denture Base

Author: Dr.Ghassan A. Al-Taie, BDS, MSC.* د.غسان الطائي
Journal: MUSTANSIRIA DENTAL JOURNAL مجلة المستنصرية لطب الاسنان ISSN: 18138500 Year: 2008 Volume: 5 Issue: 4 Pages: 393-397
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

Background: Most of spaces between the denture base and master cast produced by shrinkage of the base material during polymerization and by the difference in coefficient of thermal expansion of the cast and acrylic resin. The aim of this study is to evaluate the effect of the different heating rates and the presence of residual monomer on the accuracy different curing denture base by recording the gap space between the cast and the dentureMaterials and methods: 18 maxillary edentulous stone cast were prepared then divided into three main groups, denture bases were constructed. In Group A, using Biostar plates (free of monomer) in the pressure champers. In group B, using short curing cycle while group C, using long curing cycle . The gap space between the cast and denture base was recorded using traveling microscope measuring device.Results: Biostar curing resin (group A) showed significantly the highest dimensional changes among groups (short and long curing resins). There was no significant difference between group B ( short curing resin) and group C (long curing resin). The lowest gap space values were obtained in long curing resin. All samples showed maximum discrepancy in mid palatal reign and minimum dimensional changes at the crest of ridge. Minimum gap space values were shown in the canine reign for record bases cured with short and long curing cycles, while minimum gap space values were shown in the posterior palatal seal for record base cured with Biostar machine.Conclusion: The dimensional changes of record bases mainly depend on the amount of heat applied during processing rather than the amount of residual monomer. Greater distortion was shown in record base processed by Biostar machine (Free of monomer), while the least distortion in record base processed by long curing cycle. All samples showed maximum discrepancy in the mid palatal region and minimum dimensional changes at the crest of ridge.


Article
Reinforced Microwave - Cured Acrylic Resin Denture Base Material with Glass Fibers

Authors: Mohammed A Abdulla --- Radhwan H. Hasan
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2010 Volume: 10 Issue: 2 Pages: 314-321
Publisher: Mosul University جامعة الموصل

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Abstract

AIMS: To evaluation the Effect of adding glass fibers on the transverse strength and the levels of the residual monomer of specially formulated acrylic resin to be cured by microwave and heat cured acryl-ic resin denture base materials. MATERIALS AND METHODS: The materials were used in this study heat cured acrylic resin and microwave cured acrylic resin which is formulated to be cured by microwave energy( Acronacrylic resin). Thirty two samples were prepared for transverse strength test and divided into the following groups Control group (I) heat cured alone, group (II) microwave cured alone, the group (III) heat cured+fibers, group (IV) microwave cured+fibers the transverse strength was evaluated by using an Instron testing machine . Thirty two samples were prepared for residual mono-mer test and divided into four groups water bath and microwave cured with and without glass fibers, the residual monomer was evaluated by using ultraviolet visible spectrophotometer for seven days. RESULTS: Transverse strength test: Statistical Analysis of Variance(ANOVA) shows that there is significant differences at (p>0.0001)among the four groups and Duncan's multiple range test showed that microwave cured + fibers significantly higher transverse strength followed by heat cured +fibers, microwave alone, while heat alone shows significantly lowest transverse strength. Residual monomer test: Analysis of variance(ANOVA) for the four groups from the first day of immersion in water until 7th day shows that there are significant differences between the four groups in the all six days except the 7th day shows that there are no significant differences among the four groups for the level of the residual monomer. CONCLUSIONS: Microwave cured acrylic resin with glass fibers have signifi-cantly higher transverse strength than that of acrylic resin cured by water bath, also microwave cured acrylic resin have significantly lower residual monomer content from the 1st day of immersion when compared to that of water bath which show the same level of residual monomer at the 7th day of im-mersion


Article
Acrylic denture base repair (Part III): Influence of repair procedure on color and residual monomer

Authors: Nadira A Hatim --- Mohammed M Sadoon
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2006 Volume: 6 Issue: 3 Pages: S123-S132
Publisher: Mosul University جامعة الموصل

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Abstract

To evaluate the effect of repair techniques, surface treatment with monomer, and additional curing cycle on the color change, and residual monomer of the repaired denture base. Materials and methods: Two hundred and seventy two samples of two brands heat cured acrylic resin were repaired by four different techniques (water bath, microwave, thermo press, and chemically cured acrylic resin), treated, and untreated with monomer, and repaired with 3 mm space at fracture area. The samples were tested to measure color change and residual monomer of repaired, and intact (control) samples. Results: Color change of acrylic denture base repaired by chemically cured acrylic resin was significantly higher than that of water bath, microwave, and thermo press. Microwave repairing technique had lower residual monomer than other techniques. The highest content of residual monomer was released in water after the first 24 hours and decreased in the subsequent days. Acrylic denture base that has additional curing cycle showed a residual monomer content lower than those with single curing cycle. Conclusion: Color changes of repaired denture with chemically cured resin are high and the lower adverse effect of monomer are shown with microwave and water bath curing cycle. Long storage period of repaired denture base are beneficial to reduce monomer release


Article
Residual Monomer and Transverse Strength Evaluation of Auto Polymerized Acrylic Resin with Different Polymerization Treatment.

Authors: Mohammed M Sadoon --- Nada Z Mohammed --- Alia'a O AL–Omary
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2007 Volume: 7 Issue: 3 Pages: S30-S34
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: The aims of this study are to determine the effect of different polymerization treatment on the transverse strength and residual monomer of auto polymerized acrylic denture base. Materials and Methods: Sixteen samples of heat cured acrylic resin were prepared as a control samples. Eighty samples of auto polymerized acrylic resin were prepared with different polymerization treatments to be tested for transverse strength and residual monomer concentration. These polymerization treatments were carried out by: (1) Open air polymerization treatment, (2) Under hydraulic pressure, (3) Under clamp pressure, (4) Water bath post polymerization. (5) Microwave post polymerization. One half of specimens were subjected to transverse strength test and another one subjected to residual monomer test. Data were analyzed using analysis of variance and Duncan's Multiple Range Test. Results: The result of this study showed that the microwave post polymerization treatment had significantly higher transverse strength, and also showed that the residual monomer significantly lower with microwave and water bath post polymerization treatment. Conclusions: The fracture resistance was improved after post polymerization treatment for auto polymerized acrylic denture base with microwave, and the adverse effect of monomer was decreased by water bath and microwave post polymerization treatment.


Article
Visible Light Cure Fiber Frame Work Reinforcement of Acrylic Resin Denture Base Material. A Comparative Study.

Author: Aliaa W AL-Omari
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2014 Volume: 14 Issue: 2 Pages: 173-181
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: Heat cured acrylic resin is the material of choice for construction of complete dentures due to its desirable properties, although it has some disadvantages as its susceptibility to fracture. Several methods and materials are used to reinforce acrylic resin denture base. One of these methods is reinforcement by using fibers. In this study, visible light cure fiber frame work is used as reinforcement material and compared with reinforcement with glass fiber. Materials and methods: in this study, 128 samples were prepared for evaluation of transverse strength, impact strength, surface hardness, and residual monomer tests. The samples were divided into four groups 8 sample for each group; control group without reinforcement, reinforcement by using visible light cure fiber frame work, random glass fiber reinforcement, and mesh glass fiber reinforcement. Results: the results of this study showed that visible light cure fiber frame work system significantly increase the transverse strength and impact strength of the heat cured acrylic resin, and it didn’t affect the surface hardness and amount of residual monomer of heat cured acrylic resin. Conclusions: visible light cure fiber frame work system increase acrylic resin denture base resistance to fracture.

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