eng
Shiraz University of Medical Sciences
Journal of Dentistry
2345-6485
2345-6418
2007-09-01
8
3
1
10
41414
Original Article
Effect of Fiber Orientation and Position on Fracture Resistance and Failure Mode of Cuspal Coverage Composite Restorations
F. Sharaffedin
1
AA. Alavi
2
M. Farzinfar
3
Assistant Professor, Department of Operative Dentistry, School of Dentistry, Shiraz University of Medical science
Professor, Department of Operative Dentistry, School of Dentistry, Shiraz University of Medical science
Specialist in Operative Dentistry
Statement of Problem: Position and orientation of fiber may lead to increase load bearing capacity and prevent undesirable fractures in cuspal coverage composite restorations.Purpose: The aim was to evaluate the effect of fiber position and orientation on fracture resistance and failure mode of composite cusp capping restorations.Materials and method: In this experimental study, MOD cavities with 2.5mm cuspal reduction were prepared in 50 human maxillary premolars. The teeth were divided into five groups (n=10) and all teeth were restored with packable composite resin (P60). In the first group no fibers were applied. In the second group one strip of fiber was inserted into resin composite in buccal to palatal direction. In the third group two strips of fiber were inserted in buccal to palatal and mesial to distal direction by crossing in central part of cavity. In the forth group, one strip was directed from mesiobuccal to distopalatal and the other from distobuccal to mesiopalatal line angle. In the fifth group, two strips of fiber were inserted in buccal to palatal direction with 1.5 mm distance. The teeth were stored in water for 7 days in room temperature and then thermocycled 500 times between 6±2 and 60±2 centigrade degrees. The specimens were subjected to compressive loading perpendicular to the occlusal surface. The necessary fracture loads were recorded in (KN) and the results were statistically analyzed by Mann-Whitney and ANOVA tests. Mode of fracture was analyzed by using Fisher test.Results: Statistical analysis showed a significant increase of fracture load from control to the other four groups (p<0.05). There were statistically significant differences between second and third groups (p=0.034) as well as second and fifth groups (p=0.041). No significant differences were found between other pairs of groups. Also significant differences were observed in failure mode between composite restorations with and without fiber, except for second group (p<0.005).Conclusion: Fiber reinforced composites improve fracture resistance and failure mode of restorations with cusp capping. With increase use of fiber strips in special directions, fracture resistance will be rised.Key words: Fracture resistance- Failure mode- Cusp capping- Fiber- composite
https://dentjods.sums.ac.ir/article_41414_7602b23535044f972eeb3b56a7ace219.pdf
eng
Shiraz University of Medical Sciences
Journal of Dentistry
2345-6485
2345-6418
2007-09-01
8
3
11
23
41416
Original Article
Effect of Obturation Techniques on Obturation Quality of Molar C-shaped Canals
J. Ghoddusi
jghoddusi@gmail.com
1
MH. Zarrabi
23014@irimc.org
2
N. Ghafariyan
3
Associate Professor, Department of Endodontics, Member of Dental Research Center, Faculty of Dentistry, Mashhad University of Medical Sciences
Professor, Department of Endodontics, Member of Dental Research Center, Faculty of Dentistry, Mashhad University of Medical Sciences
Endodontics
Statement of Problem: Due to the anatomic complextieis of C-shaped canals, using an obturation technique capable of filling the irregular isthmus in the root canal system seems to be necessary.Purpose: The aim of this study was to compare the efficacy of three different root canal obturation techniques used for filling the irregular root canal system in C-shaped teeth.Materials and method: The study was perfomed on 30 human extracted molar teeth which were radiographically and anatomically recognized as having C-shaped canals. All root canals were prepared in the same way and the samples were divided into 3 groups, each of 10 teeth. The root canals in group I were filled by cold lateral condensation technique (CL). Teeth in group II were filled by means of warm lateral condensation technique (WL) and those in group III were filled by means of warm vertical condensation technique (WV). All teeth were demineralized and then cleared with methylsalicilate. Images were taken from both longitudinal and cross-sectional feature of the cleared teeth by a digital camera connected to a stereomicroscope. The filling quality of the main canals and the isthmus between them was evaluated by three independent endodontists. The data were statistically analyzed by chi-square, one way and two way ANOVA and t-test.Results: In longitudinal photographs, the highest percentage of good filling quality (80%) was observed in the WV group and was significantly more acceptable than WL group (p<0.05). The lowest percentage of good filling quality was observed in the isthmus area of the canals (46.7%) which was significantly less than other areas (p<0.05). Cross- sectional photographs demonstrated no significant difference between the percentage of isthmuses filled with the filling material and the two areas of the canals in the three obturation techniques (p>0.05)Conclusion: The results indicated that none of the suggested techniques could successfully fill the root canal space, but the warm vertical and cold lateral condensation techniques were more acceptable than warm lateral condensation technique.Key words: C-shaped canals, Obturation quality, Obturation techniques, Molar teeth
https://dentjods.sums.ac.ir/article_41416_e0c4d667732ce8275975c415bda9a4c7.pdf
eng
Shiraz University of Medical Sciences
Journal of Dentistry
2345-6485
2345-6418
2007-09-01
8
3
24
32
41417
Original Article
Effect of Cigarette Smoking Quantity on Periodontal Tissue Response to Phase I Therapy
N. Aboulfazli
1
F. Saleh Saber
spintanad@hotmail.com
2
A. Lafzi
amidr@sums.ac.ir
3
A. Eskandari
amirr22@yahoo.com
4
Assistant Professor, Department of Periodontics, School of Dentistry, Tabriz University of Medical Sciences
Assistant Professor, Department of Periodontics, School of Dentistry, Tabriz University of Medical Sciences
Associate Professor, Department of Periodontics, School of Dentistry, Tabriz University of Medical Sciences
Assistant Professor, Department of Periodontics, School of Dentistry, Tabriz University of Medical Sciences
Statement of problem: Although bacterial plaque is the primary ethiologic factor in the initiation of chronic periodontitis, there is some predisposing factors such as smoking which may aggravates disease process and its roll appears to be considered more important recently.Purpose: The purpose of the present study was the evaluation of the effect of the quantity of cigarette smoking on periodontal tissue response following phase I therapy.Materials and method: Thirty patients (26 male and 4 female) with mean age of 48±11 years participated in this interventional and cross-sectional study. All patients suffered from generalized moderate chronic periodontitis. The patients were divided into three equal groups of 10 (heavy smokers, light smokers and non smokers), according to the number of cigarette consumption. The smoker groups had a history of cigarette consumption at least for the past two years. Clinical probing depth, clinical attachment level and bleeding on probing were evaluated for the patients at baseline and eight weeks following completion of phase I therapy. The results were analyzed using Wilcoxon rank and Kruskal- Wallis tests.Results: No statistically significant differences were found in the evaluated variables between the groups except for BOP at baseline. All parameters decreased significantly eight weeks after completion of phase I therapy, but in comparison between three groups, only differences of CPD reduction and CAL gained between heavy and non-smokers were statistically significantConclusion: The present study indicated that heavy cigarette smoking have a negative effect on periodontal tissue response to phase I therapy. This effect depends on the number of daily smoked cigarettes and is increased with more than 20 cigarettes smoking per day.Key words: Response to periodontal treatment, Non surgical periodontal therapy, Smoking
https://dentjods.sums.ac.ir/article_41417_f262f7ab5313c10583f59708ea5bc1e6.pdf
eng
Shiraz University of Medical Sciences
Journal of Dentistry
2345-6485
2345-6418
2007-09-01
8
3
33
41
41418
Original Article
Effect of Different Placement Techniques and Curing Methods on Composite Microhardness in Class I Restorations
N. Sarabi
dr_hamedeh@yahoo.com
1
H. Ameri
2
MJ Moghadas
3
Assistant Professor, Department of Operative dentistry, Member of Dental Research Center, School of Dentistry, Mashhad University of Medical Sciences
Assistant Professor, Department of Operative dentistry, Member of Dental Research Center, School of Dentistry, Mashhad University of Medical Sciences
Assistant Professor, Department of Operative dentistry, Member of Dental Research Center, School of Dentistry, Mashhad University of Medical Sciences
Statement of problem: The polymerization of light cured composite resins is initiated from surface layer and the rate of polymerization reduces from surface to depth. The difference in hardness is in correlation with different factors such as the intensity of unit and the distance between composite and light tip.Purpose: The aim of this study was to compare the effect of four different methods of filling and two light direction on microhardness of class I composite resin restorations.Materials and method: In this parallel interventional study, 40 intact human premolar teeth were selected. Class I cavities were prepared (4×4×4 mm). After etching and applying Excite as a dentin adhesive, the specimens were divided into four groups (n=10) based on the filling methods: Group 1)one bulk, group 2)horizontal incremental and occlusal light curing, group 3)horizontal incremental and three directional light curing, Group 4)oblique and three directional light curing. Z100 was used for restoration of cavities. Microhardness of specimens was measured by kicker's microhardness tester in 0, 1.5, 2.5 and 3.5 mm distance from surface. Data were analyzed using ANOVA and Duncan tests (_=0.05).Results: The mean value of microhardness in groups 1 and 2 showed significant difference from that of groups 3 and 4 (p<0.05). Within each group, the subsurface layer showed the highest value of hardness (P<0.05) except for group 2 that all surfaces showed a similar hardness value (p>0.05).Conclusion: Based on the results of this study, incremental technique (oblique or horizontal) with three dimensional light curing is the most suitable procedure for obtaining a maximum hardness in Class I composite resin restoration.Key words: Composite resin, Microhardness, Class I cavity, Incremental technique
https://dentjods.sums.ac.ir/article_41418_c3c6117371921e01efc8253acad9b143.pdf
eng
Shiraz University of Medical Sciences
Journal of Dentistry
2345-6485
2345-6418
2007-09-01
8
3
42
49
41419
Original Article
Comparison of the Effect of Different Chewing Gums and one Mouth Wash on the Amount and PH of Saliva in Healthy Individuals
A. Azizi
1
Sh. Lawaf
drlawaf@yahoo.com
2
M. Najafi
3
Assistant Professor, Department of Oral Medicine, School of Dentistry, Ahwaz University of Medical Sciences
Assistant Professor, Department of Prosthodontics, School of Dentistry, Ahwaz University of Medical Sciences
Dentist
Statement of Problem: Saliva serves an important role in oral homeostasis. Protection against viruses, bacteria and fungus and dental remineralization are some roles of saliva. Xerostomia is a common complaint, especially among elderly woman and is usually the result of the salivary gland dysfunction. It may be beneficial to stimulate the salivary flow by sugar free chewing gums or substituting saliva by oral rinse, in patients with impaired salivary function.Purpose: The purpose of this study was to evaluate the effect of stimulating materials such as, chewing gums and one oral rinse on the amount and pH of saliva.Materials and method: In this experimental study, 60 healthy individuals were randomly divided into four groups, each composed of 15. Before study, the mean amount and PH of the whole saliva were evaluated in 2 minutes. In group 1, 2 and 3 Orbit, Relax and Biotene chewing gums were used for 5 minutes, respectively. In the forth group, Biotene mouth wash was used for 30 seconds according to the manufacture’s instruction. The mean amount of saliva in 2 minutes and mean of saliva PH were determined immediately and 45 minutes after use of the materials. Covarince analysis and the Least Significant Difference test were used for data comparison among groups and T-test was used for intra groups analysis.Results: In all groups the mean amount of saliva increased immediately after using the materials, but after 45 minutes, though significantly higher than the initial one, the mean amount decreased. The mean of PH increased immediately after chewing the gums, but after 45 minutes use of the gums, only for Relax and Biotene gums, the mean of saliva PH was significantly higher than the initial record. Biotene in the form of mouthwash did not show any effect on PH of the saliva.Conclusion: Xylitol with mechanical factors such as chewing increases the amount of saliva and improves PH of the oral cavity. Relax and Biotene chewing gums, having no glucoses and contain only xylitol, due to the increase in amount of saliva and improvement of PH, should be considered as preferred chewing gums.Key words: Chewing- gum, Mouth wash, Salivary flow rate, Salivary PH, Xylitol
https://dentjods.sums.ac.ir/article_41419_124ef602eb54b16ee1d362aeb3edefc1.pdf
eng
Shiraz University of Medical Sciences
Journal of Dentistry
2345-6485
2345-6418
2007-09-01
8
3
50
59
41420
Original Article
Developmental Enamel Defects of the Primary Dentition in Children with Low and Normal Weight Birth
N. Asl Aminabadi
n_aminabadi@yahoo.com
1
Assistant Professor, Department of Pediatric Dentistry, School of Dentistry, Tabriz University of Medical Sciences
Statement of problem: Low birth weight (LBW) infants are subjected to a variety of metabolic stresses and exhibit a higher prevalence of oral-dental disturbances than normal infants. Factors such as metabolic disorders, hypoxia, prolonged neonatal jaundice, nutritional deficiencies and low serum calcium have been implicated as causes of enamel defects in LBW infants. These enamel defects lead to the alteration of primary teeth with subsequent problems such as esthetic concerns, dental caries and dentofacial problems. Purpose: The aim of this study was to compare the developmental enamel defects in the children with lower than normal weight at birth (less than 2500 gr) and children with normal birth weightMaterials and method: In this retrospective (expose–fact) study, 181 children (95 girls and 86 boys) aged 3 to 5 years were examined. The data were collected using infants birth files and questionnaires based on the general information, birth time and weight as well as medical examination. Dental examination was performed by two examiners. Developmental Enamel Defect Index was used to classify the enamel defects. Data were statistically analyzed by SPSS13. Kappa test was used for evaluating validity between examiners (Kappa≥0.8) and two-sampling proportional test by means of Mini Tab software was used for data analysis.Results: Enamel defects were more in children with low birth weight compared to the normal children (p<0.05). There was no statistically significant difference in hypocalcification and hypoplasia between girls and boys with LBW and also between girls and boys with normal birth weight (p>0.05). Enamel defects were most common in both groups on the canine teeth (% 51.3) followed by incisors, first molar and second molar teeth.Conclusion: Based on the results of the present study, without considering etiologic factors, hypocalcification and hypoplasia was noticed more in children with low birth weight. Further studies are needed to evaluate the relationship of enamel defects and various causative factors in these children.Key words: Enamel defect, Primary dentition, Low birth weight
https://dentjods.sums.ac.ir/article_41420_d5a416d9fdf326d481be70294a8e2e01.pdf
eng
Shiraz University of Medical Sciences
Journal of Dentistry
2345-6485
2345-6418
2007-09-01
8
3
60
70
41421
Original Article
Relationship between Satisfaction and Expectation with Self-esteem and Self-concept in Patients Using Complete Denture
R. Mosharraf
1
A. Aghaee
2
A. Hasan Zadeh
3
M. Poor Agha Koockak
4
Associate Professor, Department of Prosthodontics, School of Dentistry, Isfahan University of Medical Sciences. Member of Torabinejad dental research center
Assistant Professor, Department of Psychology, Khorasgan Azad University
Academic member and statistics Department of Epidemiology, Isfahan University of Medical Sciences
Dentist
Statement of problem: Denture acceptance as a complex process is dependent not only on ridge morphology, theoretical and practical skills of dentist, but on many psychologic factors which need to be considered seriously.Purpose: The aim of this study was to determine the relationship between complete denture satisfaction and expectation with patient’s self-esteem and self-concept.Materials and method: This descriptive-analytical study was undertaken on 52 patients (28 male and 24 female) referred to the prosthodontic department of Khorasgan Azad University. The mean age was 53.4 with the range of 35-70 years. The personality variables were measured using two standard psychological tests (Rosenberg and California tests). Before and after full denture delivery, patients completed the denture expectation questionnaires. After using new dentures for 3 months, the patients’ satisfaction was evaluated by related questionnaires. T-student, T-paired and Pearson coefficient tests were used for data analysis.Results: There was no significant relationship between expectation and self-concept likewise between self-esteem and satisfaction (p= 0.42, 0.18). A moderate relationship was found between self-esteem and expectation (p=0.05), while a significant relationship was obtained between self-concept and satisfaction (p= 0.01).Conclusion: According to this study, it was revealed that complete denture treatment did not have any significant effect on patients’ personality variables, but there was a significant relation between patients’ self-esteem and complete denture satisfaction. Also patients with high self-esteem scores showed better expectations with their dentures. Key words: Self-concept, Self-esteem, satisfaction, Expectation, Complete denture
https://dentjods.sums.ac.ir/article_41421_8aa47cab0de15ce3dd2a1a5bf40be5bf.pdf
eng
Shiraz University of Medical Sciences
Journal of Dentistry
2345-6485
2345-6418
2007-09-01
8
3
71
80
41422
Original Article
Comparison of Air Driven Handpiece and Electromotor on Distortion or Fracture Rate of Nickel Titanium Rotary Instruments
MH. Zarrabi
23014@irimc.org
1
M. Javidi
javidim@mums.ac.ir
2
M. Vatanpour
3
H. Esmaeili
4
Professor, Department of Endodontics, Member of Dental Research Center, Faculty of Dentistry, Mashhad University of Medical Sciences
Assistant Professor, Department of Endodontics, Member of Dental Research Center, Faculty of Dentistry, Mashhad University of Medical Sciences
Assistant Professor, Department of Endodontics, Islamic Azad University, Dental School
Assistant Professor, Department of Community Medicine, Mashad Medical School
Statement of Problem: One of the affecting factors in adverse prognosis of root canal therapy is procedural accidents as broken files, facing with difficulty in removing. Many manufacturers have designed and marketed various electromotors with the ability of controlling rotational speed and torque. On the other hand, these expensive motors have encouraged other manufacturers to marketing different air driven handpieces. Despite of presenting various vast instruments for this purpose, only limited comparative studies have been carried out between electromotor and air driven handpiece.Purpose: The purpose of this study was to evaluate the effect of air driven handpiece versus electromotor on distortion or fracture rate of NiTi rotary files.Materials and Method: This in vitro randomized controlled trial was carried out on 160 canals of human’s matured molars with mild curvature (15-33o). After initial preparation of samples and considering the inclusion criteria, in the first group, preparation was carried out with air driven handpiece and in groups 2 Endo IT (VDW, Germany) was used as electromotor. In both groups Mtwo files with crown down technique were used for canal preparations. Data on file distortion or fracture were collected and analyzed using Mann Whitney, Mantel Cox, Kaplan-meiere and T tests.Results: No significant differences on distortion or fracture rate of files between the two groups were found (p>0.05). Based on survival analysis safety probability of files after preparation of 9 canals was %64.1 in group 1 and %69.9 in group 2. There was no significant differences between this safety probability in the two groups (P=0.272).Conclusion: These findings showed that both electromotor and air driven handpiece has nearly similar effect on fracture rate or distortion of NiTi rotatory instruments.Key Words: Electromotor, air driven handpiece, distortion, fracture, NiTi rotary file
https://dentjods.sums.ac.ir/article_41422_f428181687db2b07fae54836a0cd4fc4.pdf
eng
Shiraz University of Medical Sciences
Journal of Dentistry
2345-6485
2345-6418
2007-09-01
8
3
81
91
41415
Case Report
A Case Report: Papillon- Lefevre Syndrome in a-12-year Old Girl
D. Amanat
andisheh@sums.ac.ir
1
M. Mardani
2
Assistant Professor, Department of Oral Medicine, School of Dentistry, Shiraz University of Medical Sciences
Assistant Professor, Department of Oral Medicine, School of Dentistry, Shiraz University of Medical Sciences
Papillon- Lefevre Syndrome (PLS) is a rare, autosomal recessive disease with no known etiological factor, which reveals loss of function mutations affecting both the alleles of the cathepsin- C gene. The disease is characterized by palmo-plantar keratoderma and early juvenile periodontitis affecting both primary and permanent teeth. Due to the severe alveolar bone loss both in deciduous as well as permanent dentitions, teeth are exfoliated within two or three years after eruptions. By the age of 15 or 16, patients are usually edentulous except for the third molars. These teeth are also lost a few yeas after they erupt.No treatment has been shown to be effective for keeping teeth. Prognosis for prevention of teeth loss is hopeless. Available treatment plans such as stabilization of the alveolar bone height improve the prognosis for a lifetime of complete denture use.In this article, a- 12- year old girl living in Bandar Abbas who has been referred to Oral Medicine Department of Shiraz Dental School for further evaluation, diagnosis and proper treatment plan is reported.Key words: Papillon- Lefever syndrome, Palmo plantar hyperkeratosis, early periodontitis
https://dentjods.sums.ac.ir/article_41415_be1a88cdce2121d91770aac39cddb07c.pdf