About Journal

Al-Rafidain Dental Journal is an English language, peer-reviewed scholarly publication in the area of dentistry.  Refereed Scientific Journal deals with fields of dental sciences Date of first issue: 2001 No of Issues: 27 issues publishing biannually till 2012 publishing becomes triannually at 2013  
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Journal Information

Publisher: Mosul University

Email:  rden@uomosul.edu.iq

Editor-in-chief: Professor Dr. Nada M. Saeed Al-Sayagh

ISSN: 1812-1217

The Effect of Chemical Disinfectants on the Setting Time and Dimensional Change of Alginate Impression Material.

Al-Rafidain Dental Journal, Volume 14, Issue 25, Pages 1-8

Aims: The aim of this study was to evaluate the effect of mixing different concentrations of chlorhexidine, iodine ,and sodium hypochlorite solutions on the setting time and dimensional change of alginate impression material. Materials and methods: Total number of samples (40) has been prepared in this study. Ten samples for control group made from pouring alginate impressions of metal model .The other groups made by mixing alginate with 0.05% iodine, 0.5% chlorhexidine and 0.5% sodium hypochlorite solutions. Dimensional change was measured with AutoCAD program .The Setting time was also measured for each group. Statistical analysis was performed using ANOVA and Duncan multiple range test. Results: no significant difference in the linear dimensional change among the tested groups ,sodium hypochlorite added to alginate as disinfectant showed the highest dimensional changes among the other groups. There was a significant difference among the tested groups in the setting time. It was found that treating the alginate with sodium hypochlorite and chlorhexidine disinfecting agents accelerated the setting time of the material. Conclusion: The testing disinfecting agents can be used safely regarding dimensional change.

Effect of various surface treatment procedures on shear bond strength of stainless-steel orthodontic brackets to composite resin

Al-Rafidain Dental Journal, Volume 14, Issue 25, Pages 21-30

Aims: The aim of this study was to evaluate the shear bond strength of brackets bonded to composite restorations using four types of surface conditioning procedure. Materials and Methods: Thirty two cylindrical cavities were made at the center of self-cured acrylic resin blocks. All cavities were then filled with composite resin. The specimens were randomly divided into four groups. Group one: Composite surface was acid etched with 37% phosphoric acid. Group two: After using 37% phosphoric acid, bonding agent was applied and cured. Group three: After using 37% phosphoric acid silane coupling agent was applied then bonding agent was applied. Group Four: The composite surface roughened with a diamond bur, and then 37% phosphoric acid was applied. Brackets were bonded onto the composite prepared samples with Transbond XT. Shear Bond Strength was measured by a universal testing machine. KruskalWallis test was utilized for data analysis. Results: There was a significant difference between the four groups. The highest bond strength was that of Group 3. Group 1 had the lowest bond strength. Conclusions: Roughening the composite surface before acid etching was effective to improve the bond strength of orthodontic brackets to composite restorations. Addition of silane before bonding agent application result in highest bond strength.

Detection of Hepatitis B Antigen in The Dental Instruments Used in Public Dental Clinics in Duhok Province, kurdistan Region/ Iraq

Al-Rafidain Dental Journal, Volume 14, Issue 25, Pages 42-47

Aims: Hepatitis B virus infection is a global health hazard. The virus can be transmitted by both parenteral and non- parenteral methods such as direct contact with mucus membrane. Dental instruments can be the source of infection, therefore this study was conducted to detect HBs Ag in dental instruments used in the different public dental centers and clinics in Duhok governorate. Sampling process was from December 2016 to January 2017. Materials and Methods: A total of 549 samples were collected from five different districts as follow: 238 samples from center of Duhok, 121 samples from Zakho, 87 samples from Amedi, 68 samples from Sumail and 35 samples from Aqre. Four different commonly used dental instruments were chose namely: Scaler tips, curette, sickle and chisele. The samples divided into sterilized and used using capital A letter for sterilized and small a letter for used samples. Results: No HBs Ag was detected in all tested samples both sterilized and non- sterilized samples by ELISA technique. The results of the present study indicated to the proper hygienic precautions implemented in public dental centers and clinics as well as to the effectiveness of anti-HBV vaccine that almost all dentists had been received prior working. Conclusions: Further studies are required to cover private dental instruments as well as dentists and assistant technicians using both ELISA and RT-PCR techniques.

Assessment of Peri Implant Osteal Changes by Radiographic Evaluation Using Standard Orthopantomograph and Periapical View a Retrospective Study

Al-Rafidain Dental Journal, Volume 14, Issue 25, Pages 59-66

Aims: The aims of the study are to evaluate the radiographical views, OPG and periapical views on the changes in peri- implant bony tissue around dental implant at time of placement and another reading after 16 weeks before functional prosthetic loading and regard it as a prognostic parameter. Material and methods: Nineteen cases with 24 implant were enrolled for standardization. Radiographical measurement undertaken by a periapical and OPG radiographs after implant placement, then after16 weeks later, again a second periapical and OPG radiographs were taken for measurements using Dimaxis 3.2.1. Software program to estimate marginal bone height of both sides of implant and its changes during times of evaluation. Results: 19 medically fit patients, male and female with age 22-65 years, twenty four implants with average bone loss 0.59 mm mesialy and 0.60 mm distally at T0 as standered base line in compared to 0.98mm mesialy and 1.11mm distally at T1as average bone loss. There was a significant bone resorption in both sides in relation of implant size and in comparison to time of placement and after 16 weeks according to statistical analysis. Conclusion: OPG and periapical views are a good parameter for evaluation of successful implant and monitoring of the prognosis and stability and durability, as these radiographs more available in most dental centers and clinics with less cost.

The effects of two bone substitute materials in the treatment of experimentally induced mandibular defects: An experimental study

Al-Rafidain Dental Journal, Volume 14, Issue 25, Pages 9-20

Aims: To compare between the effects of deproteinized bovine bone (DBB) and osteon in the healing of mandibular bone defects in the rabbits. Materials and Methods: This experimental study was conducted on ten rabbits at the Animal House, Dentistry college, Mosul University. The rabbits weighted between 1.5 and 2 kg and each rabbit was given anesthesia (10% ketamine (40 mg/kg) and 2% xylazine (5 mg/kg). Surgery was performed aseptically. Mandibles were exposed through a sub-mandibular incisions. Three rectangular full thickness defects (6×5 mm) were created in each side. The first defect in each side was filled with DBB, the second defect was filled with osteon, while the third defect was left untreated to serve as a control. Five rabbits were sacrificed after one week and the other five rabbits were sacrificed after one month. The bony mandibles were immersed in 10% formalin solution and examined histologically by two histopathologists. Results: Microscopically, sections for one week of all groups showed mild degree of inflammation, moderate amount of vascularity, granulation tissue and osteoid tissue formation. Sections of one month showed no difference regarding the degree of inflammation vascularity, but the amount of granulation tissue and osteoid tissue formation in the control group were lesser than the amount seen in both experimental groups. Conclusions: DBB and osteon accelerate bone healing after month regarding the amount of granulation tissue and osteoid tissue formation.

Calibration Factor for Conventional Linear Cephalometric Measurements

Al-Rafidain Dental Journal, Volume 14, Issue 25, Pages 31-41

Aims: the aim of this study is to determine a calibration factor to eliminate the distortion in the linear cephalometric measurements. Materials and Methods; the study was performed on the 5 dry skulls, the first skull contained 12 radiopaque markers fixed at different plains, and radiographed by digital cephalometric x-ray machine. The X and Y axes of the shadow of each radiopaque marker used to estimate the calibration factor. Eight linear distances measured directly and radiographically on the conventional cephalographs of the 5 skulls to evaluate the detected calibration factor. Results; the results showed no-significant difference (p > 0.05) between the direct and calibrated radiographic measurement on the digital and conventional cephalographs. whereas significant difference was found between the conventional cephalometric linear measurements as compared with direct anatomical linear and the conventional cephalometric linear measurements with those measurements manipulated with the estimated calibration factor (p < 0.05). Conclusions; this study found that the conventional cephalometric linear measurements could be reliable as that of digital cephalometric linear measurements, if it's calibrated by the calibration factor (1.08) which is estimated by the present study.

Perception of Pain by a Sample of Patients Undergoing Orthodontic Treatment in Sulaimani City

Al-Rafidain Dental Journal, Volume 14, Issue 25, Pages 48-58

Aims: Orthodontic treatment is known as a painful procedure among patients. They feel varying degrees of pain during orthodontic treatment from the stage of initial examination till the end of the treatment. The aims of this study are to explore pain experience among patients undergoing orthodontic treatment with the fixed appliances by comparing two different arch wires sizes. Materials and Methods: The study group consisted of 60 patients (26 males, 34 females) with a mean age of 17.6 years and 20.5 years consequently. Insertion of either 0.014 or 0.016-inch wire was by random selection of patients. Patients were asked to fill out a series of questionnaires for five consecutive days after the insertion of orthodontic initial arch wire, and after the arch wire activation for 4 hours, 6 hours, 24 hours, and till 5 days. The intensity (weak, mild, moderate, severe, and intensive) of the pain symptoms in connection with ten items (Biting on a hard/soft food, sensitive to hot or cold food/drink, mastication of food, fitting anterior and fitting posterior teeth together, cheeks, lips, and tongue pain) have been evaluated. Results: No significant differences were found between age groups, and between the two arch wire groups. Pain perception was more significant in females than in males and the pain perceived at the anterior teeth was greater than posterior teeth. Pain percentage level increased gradually till reaching the peak within 24 hours after the insertion of arch wire and retained the same level in the 2nd day, then decreased till the 5th day. Perceptions of pain by fitting anterior teeth were exactly the same within the period of the first few hours in both arch wire groups, and decreased over the following hours. Conclusion: No age discrimination was found for perception of pain in the two different arch wire groups, with no significant correlation for the time with initial pain that perceived after the insertion of two different initial arch wire sizes then the intensity of pain reduced over the time. Pain was perceived as being greater at the anterior than the posterior teeth and females experienced more pain than males.

Evaluating the Effect of (W) Angle and ANB Angle in the Assessment of Anterioposterior Jaw Relationship and their correlation to gonial angle

Al-Rafidain Dental Journal, Volume 14, Issue 25, Pages 83-96

Aims: to evaluate the accuracy of W angle, ANB angle and gonial angle in assessing anterio-posterior jaw dysplasia and the correlation between them in class I , II, III patients. Materials and Methods: one hundred twenty patients (18-30) years of male and female from the center of Mosul City that met the criteria of the sample with class I, II, and III, the sample was divided into 3 groups The: 40% was male (48 cases) and 60 % was female (72 cases). Three groups 40 cases were distributed for each one of class I, II, III. Cephalometric analysis and measurement of angles were done .Results: the mean value of gonial angle for class I was 126.24±0.77° , class II cases was 123.42±0.86° and the class III cases was 127.53±0.98°;the mean value of W angle for class I was 53.953±0.309° , for class II was 48.78±1.29° and for class III was 60.96±3.00; 3; the mean value of ANB angle for class I was 2.71±0.155° , class II was 5.82±0.431°and for the class III was -3.182±0.241.The comparison between all variables in all classes showed highly significant differences at p<0.05 Pearson correlation coefficient test between parameters in class I, revealed weak positive non-significant correlation between W angle value and ANB angle value while showed weak negative non-significant correlation between gonial angle value with ANB and W angles value in class II when comparing the values of, W angle with the values of gonial angle. ANB angles revealed a weak positive non- significant correlation. On the other side, there is a weak negative non-significant correlation when comparing ANB angle value with gonial angle value; in class III when comparing the values of, W angle with gonial and ANB angles rervealed a weak negative non- significant correlation on the other side, there is a weak positive non-significant correlation when comparing ANB angle value with gonial angle value. Conclusions: none of the parameters can be considered as the most appropriate and reliable one for determining the anteroposterior dysplasia and must be considered other lines and angles in all 3 plane of space to reach accurate diagnosis and treatment planning.

The Effect of in-office Tooth Whitening on the Microhardness of Esthetic Restoration (An invitro Study).

Ammer A Sultan; Omar S Rahawi; Ashraf S. Qasim

Al-Rafidain Dental Journal, Volume 5, Issue 9, Pages 83-89

Aims: To determine if the composite resin restoration need to be replaced after power bleaching atdifferent times.Materials and methods: Three composite resins (a flowable, a conventional andceramic composite) were used for this study. Transparent discs with 2mm thickness with a hole of5mm diameter were used for the production of composite samples, six samples were made for eachtype of composite with a total of 18 samples were used. The bleaching procedure was followed on thetop surface of each sample. For each sample a newly fresh material were mixed (lase peroxide sensygel) and applied over the prepared sample. Bleaching took place for 15, 30 and 45 minutes according tothe manufacturer instructions. For the microhardness measurements, a Vickers microhardness tester(Wolpert, Germany) was used, with a 200g load. Five microhardness measurements were obtained onthe top surface of each sample on the following time periods: before bleaching, after 15 min., after 30min. and after 45 min. of bleaching. Data were analyzed using T-test, a value of p≤0.05 was consideredsignificant followed by the analysis of variance (ANOVA). Results: The results showed a significantincrease in the microhardness of all the three types of composite resins after bleaching with a differenttime when compared to the control.Conclusion The bleaching agent that was tested has a significantincrease of the microhardness of the composite resins and there is no sufficient reason to indicate thereplacement of restorations.

The Effect of Two Bonding Agents Genera-tions On Microleakage Of Composite Resin Using Two Light Curing Systems.

Nadia H Hasan; Abdulla MW AL-Shammaa; Emad F AL-Khalidi

Al-Rafidain Dental Journal, Volume 7, Issue 13, Pages 139-145

Aim: To evaluate the effect of two bonding systems and two curing systems on sealing ability of class V composite restorative materials. Materials and methods: This study was performed in vitro on 40 caries free upper first premolar teeth. The Standardized class V cavity preparation on buccal and lin-gual surfaces of each tooth was done. Then the teeth were randomly divided into two major groups each of twenty. 40 cavities were performed on these teeth and the first group7th generation bonding agent (i Bond) were applied according to the manufacturer instructions and single increment of univer-sal composite (XRV Herculite) from kerr were applied and twenty of the cavities were cured with con-ventional light cure device (astralis-5) and the other twenty cavities were cured with a LED. While the second group 5th generation (Excite bonding agent) applied according to the manufacturer instructions. And filled with universal composite (tetric).Twenty of the cavities light cured with conventional light cure device and the other twenty cavities cured with LED light cured device. Then the teeth were stored in normal physiological saline in an incubator at (37Co) half of each sub group (10 cavities) were stored for one day and the second half stored for one week. Then the teeth were thermo cycled for (200) cycles, after thermo cycling all teeth were immersed in a freshly prepared solution of 2% methylene blue for (24) hours at (37Co). Results: The results showed that there was no statistically significant difference between samples cured using conventional light curing system and those cured using LED light curing system. The type of bonding system and composite material used in this study had no sig-nificant effect on reducing microleakage. Samples aged for seven days produced significantly higher levels of microleakage than that for one day. Conclusions: All samples in this study showed microlea-kage with different levels. Microleakage increases as the age increases. Neither the types of light curing system nor the types of bonding were able to reduce microleakage.

Histometric Evaluation of Atenolol Effect on Developing Rat Dentition: Experimental Study

Asmaa S Al-Douri

Al-Rafidain Dental Journal, Volume 8, Issue 15, Pages 153-159

Aims: To investigate the histometric effect of atenolol drug on the developing dentition of rats. Mate-rials and Methods: The pregnant rats were divided into two main groups; control and atenolol treated groups. The control pregnant rats were given 1 ml distilled water orally from 12 – 18 day of gestation period, after delivery of these rats, thirty newborn rats from six mothers were sacrificed at ages 1, 5, 10 days postnataly (p.n). The experimental group were given 10 mg atenolol powder suspended in 1 ml distilled water orally, daily as a single dose from 12 – 18 day of gestation, thirty newborn rats from each six mothers were sacrificed at ages 1, 5, 10 days postnataly. The specimens were prepared for processing and staining with Hematoxyline and Eosin stains, and then examined by Motic microscope. Histometric measurements were under taken for these specimens by graticule lense. The histometric parameters used are the dentin thickness, mesiodistal dimension of molar teeth, pulp density (cellulari-ty) and eruption rate. Results: The results showed that atenolol affect on the developing rat dentition .This manifested by less dentin thickness, decreased mesiodistal dimension, increase in pulp cellularity and delay in eruption rate of lower incisor tooth in the atenolol treated groups in comparison to the con-trol groups. These observed changes are proceeded or continued as development process until last ex-premintal age 10 p.n. Conclusions: Atenolol drug delay the tooth development and affect it.

Post- surgical outcomes and prognosis of intentionally replanted lower post-erior teeth

Wafaa k Abid

Al-Rafidain Dental Journal, Volume 6, Issue 12, Pages 332-340

Aims: To evaluate intentional replantation based on clinical and radiographic assessment criteria over a two year period. Materials and Methods: The clinical trial was conducted at the Department of Oral and Maxillofacial Surgery/ College of Dentistry/ Mosul University. Twenty lower posterior teeth in twenty patients of different ages and genders were enrolled in the trial. Each patient was subjected to a standard surgical protocol for intentional replantation. The criteria evaluated were both clinical and radiographical on scheduled visits for two years for each patient. Clinical criteria included pain level, tooth mobility and sinus formation. Radiographical criteria were periapical radiolucency ,root resorp-tion and ankylosis. Results: In regard to clinical criteria, no significant statistical difference was dis-closed for pain score levels and sinus formation at the scheduled visits. However, significant difference was recorded for tooth mobility at different interval visits. For radiographic criteria , a significant dif-ference for periapical radiolucency, root resorption and ankylosis was recorded at interval visits. Con-clusion: The success of intentional replantation is likely dependent upon a minimally traumatic ex-traction, short extra-oral time with copious irrigation and meticulous instrumentation as well as careful-ly controlled postoperative patient compliance. The clinical and radiographic results of cases in the current trial were satisfactory. Further study on a much more post-operative period( more than two years) and the use of materials to improve the success of intentional replantation is encouraged.

Incidence of Mandibular Fractures Associated with Head Injury in Ninavah Governorate (2006-2007)

Mohammed K Hasouni; Ziad H Delemi

Al-Rafidain Dental Journal, Volume 7, Issue 14, Pages 370-375

Aims: The aims of the study are to find the incidences, types, sides and sites of mandibular fracture accompanied with head injuries in Ninavah Governorate. Materials and Methods: Data of trauma cases were collected from general, local, private hospitals and health sectors in Ninavah Governorate with a head injury and mandibular fracture for one year duration from June 2006 to May 2007. Age, etiology, types, hospitals, sides and sites, distribution were arranged in tables, chi square and P value used for statistic analysis. Results: The total number of head injury cases was (5828). The total num-ber of fractures mandible with and without head injury was (282) cases means (4.84%) of total number of head injury cases, while mandibular fracture with head injury cases incidence was (76) cases (1.3%) of total number of head injury cases . Conclusions: Children were the most common age group affect-ed by head injury, while geriatric age group was the least. Male showed high percentage than female in a ratio about 2:1. Low incidence of association between head injury and fracture mandible which means that there is no need for delaying maxillofacial treatment. Falls from height and bullet injuries were the common cause of head injury and fracture mandible (dentoalveolar fractures showed high incidence followed by body fractures).

The Effect of Three Coating Materials on the Candidal Growth, on the Surface and Color of A heat–Cure Acrylic Resin Denture Base

Enas Yaseen Shehab; Nadia T Jaffer; Monia MN Kandil

Al-Rafidain Dental Journal, Volume 5, Issue 10, Pages 279-288

Aims: To evaluate the effect of three coating materials: Acrylic resin coating "monopoly", olive oil andgrape seeds oil on the Candida albicans growth, and on color of a heat – cured acrylic resin denture base.Materials and methods: Three coating materials underwent pores method to find out their antifungaleffect. The effect of coating materials on the acrylic denture base surface was determined via Sensitivity testin which twenty discs of acrylic resin 6mm diameter and 2mm thickness were prepared and divided intofour groups: control (uncoated), monopoly, olive, and grape oil coated groups. These discs were added toSabouraud Dextrose agar surface and incubated for 24 hours at 37 oC and the diameter of growth inhibitionzones were measured. Then the Turbidity test was taken place, in which 60 acrylic specimens (1cm x 1cm x2mm) were prepared and immersed in 60 test tubes that were divided into four groups, each group (15specimens) was subdivided into three groups of incubation: 7, 20, and 30 days incubation period, each testtube contained 4 ml Brain Heart Infusion Broth, 0.1 ml of 24 hours Candida albicans, and its correspondingacrylic specimen, turbidity (yeast growth) was measured by a spectrophotometer at 530 nm wave length.For color change measurement test, 20 acrylic resin specimens (45 x 10 x 2.5 mm) were prepared anddistributed into four studied groups. The absorbed light was measured by spectrophotometer and termedoptical density at 345 nm. Results: All coating materials were fungicidal in pores method. Statisticalanalysis of sensitivity test showed that Candida albicans was susceptible at highest extent to monopolycoated denture base followed by the oils coated groups. In turbidity test, monopoly specimens showedantifungal activity in all periods of incubation, but the effect decreased gradually, olive and grape oil coatedspecimens exhibited their highest antifungal activity after 30 days incubation. Color change measurementsshowed that monopoly coated group had the highest optical density, while the olive and grape groupsshowed a decrease in the optical density when compared to uncoated group. Conclusions: Use of coatingmaterials on the acrylic denture base surface was beneficial, especially monopoly in terms of antifungalactivity against Candida albicans followed by natural oils (olive and grape oils). However, coatingmaterials showed a significant change in the color of acrylic denture base.

A Cephalometric Comparison of Pharynx and Soft Palate in Iraqi Adolescents and Adults Population

Nada M Al-Sayagh

Al-Rafidain Dental Journal, Volume 8, Issue 15, Pages 32-42

Aims: This paper aims to estimate and compare the pharynx and soft palatal dimensions of Iraqi ado-lescent and adults with class I normal occlusion at Mosul City and to identify any gender dimorphism within each group. Materials and Methods: Lateral cephalometric radiographs of 160 normal Iraqis what were separated into two groups (80 adolescents and 80 adults). Each group was additionallydi-vided into two subgroups according to gender (40 of each gender). Twelve linear measurements were made in all subjects; gender dimorphism and comparison between two age groups were analysed by students t test.Results:No gender differences in all variables except in retropalatal airway space (U-MPW) in the adolescents group. While, in the adults the only significant gender differences were found in the thickness of posterior nasopharyngeal wall (ad1-Ba)and in the vertical airway space (Pm-Eb).The adults had significantly larger values for superior nasopharyngeal(pm-ad2) and inferior naso-pharyngeal depth (pm-ad1) than adolescents .While ,adolescents had larger value for superior nasopha-ryngeal thickness (ad2-s) and posterior nasopharyngeal thickness(ad1-Ba) than adults in both genders .The adult male had a higher value for (Pm-Eb) than adolescent male .While ,adolescent female had a higher value for soft palate thickness (SPT) than adult female. Conclusions: Data derived from this study should be a useful reference for assessment of sleep apnea and other conditions in the Iraqi popu-lation.Developmental changes were found in all nasopharyngeal parameters except the Pm-ba(sagittal depth of the bony nasopharynx).

Finite Element Analysis of Acrylic Denture Produced From Visible Light Custom Tray

Ibtehal H Al-Zubaidy; Ayad A Abdul-Razaq; Nadira A Hatim

Al-Rafidain Dental Journal, Volume 5, Issue 9, Pages 9-16

Aim: To determine stress analysis exerted by denture on the edentulous alveolar bone in the premolarregion represented by stone cast produced from visible light custom tray using linear finite elementmethod. Material and Method: Visible light custom tray (spaced and close fit) was used to producestone cast that represent the denture base and the underlying bone using silicone impression material.The dimension of the cross section of the stone cast was measured using Dimax program, then the datacollected was entering Excel program for making the figures. The dimension of the cross section of thestone cast entering finite element program and other new auxiliary program prepared specially for thisstudy for finite element analysis of vertical load of 100 Newton applied on the buccal cup (supportingcusp) of the second premolar tooth. Result: After the data was analyzed, the results were drawn infigures using surfer 7 program. High compressive, tensile, deflection, shear and maximum principalstress values were observed below the point of force application and in the underlying structure withdifferent values and locations according to the analysis in the mucous membrane and in the underlyingbone in the X and Y axes. Conclusion: By using finite element analysis, the more stress concentrationand deflection were found below the point of force application, in the mucous membrane, at the beginningof the cortical bone and along the buccal vestibule. The less stress concentration, deflection andless value of shear and maximum principle stress that distributed over large distance was found by usingvisible light cure spaced custom tray

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

Mohammed A Abdulla; Radhwan H. Hasan

Al-Rafidain Dental Journal, Volume 6, Issue 12, Pages 314-321

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

Modification of Gypsum Products (Part III): Practical Application of Modified Gypsum Products

Mohammed A Abdullah; Isam K Al-Khayat; Nadira A Hatim

Al-Rafidain Dental Journal, Volume 6, Issue 11, Pages 17-24

Aims: To determine the suitability of new modified Iraqi plaster and modified Plaster of Paris as a cast in microwave curing of acrylic denture base material, and microwave and open air drying methods on the surface roughness and dimensional accuracy of the cast. Materials and methods: Two types of gypsum products were used in this study {(Iraqi plaster, Plaster of Paris) with the combined additives (Gum Arabic 0.5%, calcium oxide 0.75%, and ferric oxide 0.2%), and Type III stone Plaster/Stone 3:1} that incorporated within the two gypsum products. The effects of drying method and combined additives on the surface roughness and dimensional accuracy of the experimental gypsum products, and acrylic denture base pro-duced from the modified gypsum casts have been evaluated. Mean, standard deviation, variance (ANOVA), and Duncan's multiple range tests were used to analyze the measurements. Results: ANOVA test showed that there was a significant difference in the surface roughness and dimensional accuracy between Iraqi plaster and plaster of Paris with or without additives dried in open air and microwave techniques. Conclu-sion: There was slight dimensional change in the gypsum cast with additives of clinical importance to compensate the polymer shrinkage of the acrylic denture base after cooling. There was no significant dif-ference in the average roughness of acrylic resin cured by microwave oven as a curing method. Keywords: acrylic, roughness, dimensional accuracy.

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