Journal of Dental School
Year:2007 | Volume:25 | Issue:3 (73)|Papers Count:20

Background and Aim: According to relatively high prevalence of epulis fissuratum in patients having complete denture, with its known consequences and predicaments; also, the controversy and lack of information about the prevalence of epulis fissuratum especially in Iranian dependent elderly, the aim of this study was to determine the prevalence of epulis fissuratum and its associated factors, in two senatorium of Tehran (Kahrizak, and Pasdaran) in 1384.Methods & Materials: This cross- sectional study was done on 201 dependent elderlies having complete dentures.Clinical examinations were done to diagnose and record the epulis fissuratum which is a sessile or pedanculated inflammatory fibrous hyperplastic lesion under base of the denture. Associated factors such as sex, age, site of living, retention, and stability of denture, satisfaction of denture esthetic, complete denture maker, and complete denture wearing period were studied. The prevalence of epulis fissuratum was determined and the associated factors were statistically analysed by Chi-square test.Results: The prevalence of epulis fissuratum was 16.4%. There was significant relation among the prevalence of epulis fissuratum with sex, stability, retention of complete denture and period of wearing complete denture on 24 hours (P<0.05). Other studied factors didn't have any significant relation with incidence of epulis fissuratum.Conclusion: The prevalence of epulis fissuratum was noticeable. With regard to probable displastic and precancerous changes in this lesion cohort and clinical studies are recommended.

Background and Aim: This study assessed cervical microleakage between a Ni-Cr alloy and 3 indirect polymeric veneering materials.Methods & Materials: In this experimental study, twenty one metalic frameworks (copings) were obtained by fabrication 0.5 mm calibrated wax patterns on a master cast abutment. The wax patterns were provided with 0.4 mm beaded retention on the veneering surfaces and cast in a Ni-Cr based alloy used for fixed partial dentures. The Ni-Cr copings were divided equally into 3 groups, 7 samples in each group, and veneered with 3 polymeric materials (Belleglass, Signum, Gradia). Three chemical conditioning systems (metal prep, retention flow, GC metal primer 11) were used with the respective veneering system recommended by the manufacturer; no control group was created.After, 2 weeks of storage in distilled water at 37oC, 2000 cycles at 5-55oC, and 24 hours of storage in 0.5% basic fuchsine, specimens were embedded in clear liquid casting resin and sectioned along a perpendicular cervico-incisal plane through the middle of cervical collar. The surfaces of the resulting sections were examined in the cervical area with a dimensional microscope to detect dye penetration. Scores were compared and analysed with the use of Kruskal-wallis test.Result: Signum was associated with the highest microleakage scores (1.4286 0.5345) and the least micro leakage at the interface was produced by Belleglass (0.4236 0.07868), followed by Gradia (0.8571 0.3779). Only the difference between Belleglass and Signum was significant (P=0.024).Conclusion: Within the limitation of this in vitro study, the extent of cervical microleakge between the coping and veneer depended on the particular polymeric material used for veneering. The extremes of the study were Belleglass and Signum (respectively lowest and highest leakage scores).

Background and Aim: Restoration of facial lesions has been always difficult for prosthodontists. Extraoral facial prosthesis is faced with apparent limitations such as base removable tissue, lack of large-sized prosthesis and intolerance by the patients.The use of implants may lead to a decrease in these limitations. The implant-induced retention can replace the largesized prosthesis in removable tissue bases and then, the attention may be focused on prosthesis esthetics only.The present study reports a case of implant - supported ear prosthesis with trauma history referring to Removable Prosthodontics Department of Dental School, Shaheed Beheshti University of Medical Sciences.

Background and Aim: Color matching has an important role in esthetic dentistry. The aim of this study was to evaluate composite color changes after polymerization Methods & Materials: In this experimental study, sixty cylinders of six different composite (Z100, Tetric-ceram, Point 4, Charisma, Glacier, Clearfil ST) were prepared with 3mm diameter and 2mm thickness (10 each). A frissete was placed under cylinders, composite resin was packed in each cylinder and other frissete was located on the cylinder. Digital camera was fixed at a distance of 3 cm from specimens with 45 degree angle. Photographs were taken before and after polymerization with a professional digital camera in standard daylight. Data were recorded in CIE Lab system. Color shifts were calculated as L".E.Result: The "L" value increased in "Clearfill ST" composite resin and decreased in other composites after polymerization. The "a" value increased in "Clearfill ST" composite resin and decreased in other composites after polymerization. The "b" value increased in "Z100 and Glacier" composite resin and decreased in other composites after polymerization.Conclusion: All composites showed color changes (DE<3.3).The highest color change was measured in Z100 (DE=10.75) and the least in Tetric-ceram (DE=3.79).

Background and Aim: The presence of Beta-lactamase gene in microorganisms is believed to be responsible for resistance of subsequent infections to routine and penicillin derivates antibiotics. As such bacterial resistance has been a continuing and evolving problem in the management of the case efforts are centered on the distribution of such gene to provoke clinicians to use alternative antimicrobial agents. This investigation was aimed at the presence of the beta - lactamase gene in microorganisms responsible for peri-apical infections of primary teeth.Methods & Materials: Samples were taken from dental abscess of infected teeth from a group of 40 children attending the pediatric dental clinic. They aged 4-10 with at least 1 infected primary tooth with no systemic background.Attempts were made to make sure none of the selected cases had received any antibiotics during the last two weeks prior to sampling. The rapid and fine rapid polymerase chain reaction technique (PCR) was used to identify the gene transcript including any beta - lactamase gene presence. Data were analyzed by chi-square test.Results: Assessing the collected data and a further analysis revealed the presence rate of beta - lactamase at 63.2% of the cases.Conclusion: As the presence of the beta - lactamasegene was approved in more than 60% of the cases a definite need for a more appropriate and precise antibiotic therapy of infected primary teeth is recommended.

Background and Aim: Patients with periodontitis have more risk factors for cardio - vascular diseases in comparison with healthy people. Considering higher prevalence of cardio-vascular and gingival inflammatory diseases in the society, the present study was carried out to evaluate the means of CBC, CRP, and coagulation factors as possible risk factors of cardio- vascular diseases in patients with gingivitis.Methods &Materials: In this case - control retrospective study, 40 male patients (20-25 years old) referred to Isfahan Dental School, who were selected by non-randomized sample method, were divided into 2 groups: group 1: gingivitis cases & group 2: controls (healthy gingiva). The patients underwent clinical examinations and their bleeding index (CBI) was recorded. Blood sampling was carried out in the patients meeting the study criteria and VII - factors were investigated. Data were analyzed statistically by t-test and ANOV A.Result: RBC was 5.31x106 and 5.08x106 in case and control samples, WBC was 6.35x103 and 6.16x103 in cases and controls and HB was 13.52 and 13.93 gr/dlit in case and control groups. Hematocryte, CRP, fibrinogen and VII factor were respectively 42.72%, 2.05, 215.3 and 176 incases and 43.07%, 2.04, 183.5 and 181 mg/dlit in controls. No significant differences were found between two groups in these factors.Conclusion: The results showed no significant differences between the patients having gingivitis and healthy gingival, but due to a strong probability for the bacteria and their products to enter the blood in gingivitis and aggravating atherosclerosis, it is recommended to inform the patients and society about these risk factors.

Background & Aim: Dental alloys following corrosion cause changes in oral tissues. As base metal alloys are used for fabrication of dental prostheses and are manufactured in Iran, the aim of this study was to investigate the cytotoxicity of three types of nickel - chromium base metal alloys with one type of high noble alloy on mouse fibroblast cell (L 929) by MTT test.Methods & Materials: In this experimental study, 12 disks of each alloy with 5mm diameter and 2.5 mm thickness were prepared and placed in RPMI culture medium for 48 hours & 72 hours (extract medium). Then the extract mediums were diluted in two different dilutions of 200 ml & 40 ml and their cytotoxicity were evaluated by MTT assay and compared with two control groups consist of only culture media & culture media with teflon. The amount of Nickel, chromium, copper, zinc & silver released from each alloys were measured by flame atomic absorption device.The data were analyzed by Graph Instate software, one way ANOV A and Tukey tests.Result: After 48 hours, no significant difference in cytotoxicity was found between samples and control groups. After 72 hours there was a significant difference between samples and control groups (Minalux vs. Control: P<0.01, Degubond vs. Control: P<0.001, Wiron 99 vs. Control: P<0.001, Supercast vs. Control: P<0.05). There was no significant difference in cytotoxicity with two dilutions of 200 ml & 40 ml between samples. Maximum release of nickel and chromium were observed from Minalux, silver from Degubond and zinc from Supercast.Conclusion: The cytotoxicity of three Nickel-Chromium alloys and one high noble which were used in this study was "pot different. Cytotoxicity increased with time.

Background and Aim: One of the most important criteria for clinical acceptance and longevity of cast restorations is marginal accuracy. Marginal discrepancy causes cement layer exposure, increases risk of cement wash out leading to plaque accumulation, recurrent caries and gingival tissue inflammation. This study assessed the effect of finishing line preparation design on marginal discrepancy.Methods & Materials: In this experimental invitro study, three metal dies were prepared using simulation method with beveled shoulder, chamfer and combination of both (buccal beveled shoulder encounters palatal chamfer) that addressed groups A, B and C respectively. Seven wax patterns for each die were cast in Wiron 99 (Basemetal Alloy).After seating the trameworks, marginal discrepancy was measured in two horizontal and vertical dimensions. The data were analyzed by one way ANOVA and Tukey multiple comparisons tests.Results: The significant differences of horizontal marginal opening were found among three groups in buccopalatal and mesiodistal directions (P<0.003, P<0.0001). Also, significant differences found between pair groups except to A and C in buccopalatal and A and B in mesiodistal directions. The vertical marginal opening in three groups was statistically different at mesial, distal and palatal directions (P<0.05) but not at buccal side. The vertical marginal opening differences of pair groups (A and C, Band C) at mesial, distal and palatal directions were significant (P<0.05).Conclusion: Within the limitation of this study, finishing line, preparation design significantly affects the marginal discrepancy, the least and most horizontal marginal opening was produced in beveled shoulder and the combined preparation of beveled shoulder and chamfer, respectively. Chamfer preparation caused minimum vertical marginal opening while the beveled shoulder was in the next rank with no significant statistical differences.

Background and Aim: Regarding to increasing fluoride consumption by patients and increasing currency of different kinds of mouthwashes like Persica and Irsha that claim to have fluoride, the aim of this study was to determine fluoride content and uptake in sound enamel after usage of Iranian mouthwashes in comparison with standard oral-B mouthwash.Methods & Materials: In this in vitro experimental study, the fluoride content of mouthwashes was determined. Then 30 extracted human sound premolars were randomly divided into three groups of 10 and each tooth was longitudinally bisected into experimental and control halves. A specified hemi circular area on each experimental half was treated with one of the rinses. Three case-control groups were evaluated after using Oral-B, Irsha and Irsha with brushing.The amount of fluoride uptake in enamel surface (KOH - Soluble fluoride) and structure (structurally bound fluoride) was determined by the method of Caslavska and Mc Cann. The results were analyzed by using paired t, ANOV A and LSD tests.Results: Persica didn't have any considerable fluoride but Irsha was found to have the same amount of fluoride as Oral-B (0.05% NaF). There was a statistical difference between experimental and control halves in fluoride content (P<0.05). But there was no significant difference between three groups in fluoride uptake.Conclusion: Persica did not have any considerable fluoride. There is no difference between structurally bound fluoride uptake after using Irsha with or with out brushing. But it decreased the amount of KOH-Soluble Fluoride.

Background & Aim: The previous studies demonstrated that there is a strong relationship between the levels of Aspartate aminotransferase (AST) and the progression of the periodontal disease. The aim of this study was to evaluate the level of this enzyme in various stage of the periodontal disease.Methods & Materials: Sixty volunteers participated in this historical cohort study. They were divided in three groups of 20 each; group 1 (healthy periodontium), group 2 (early periodontitis), and group 3 (advanced periodontitis).Following periodontal examination including plaque index, bleeding on probing, pocket depth, and attachment level, 1ml of unstimulated saliva was collected and evaluated for the differences by means of Kruskal Wallis and student t tests.Result: There was a higher level of the enzyme in the saliva of the subjects with advanced periodontitis (67.95 16.4) compared to periodontally normal (36.8 13.5) and early periodontitis (43.45 18.4) patients, and the difference was highly significant (P<0.0001).Conclusion: There seems to be a positive relationship between periodontal disease severity and the higher value of the AST enzyme in saliva. The results should be confirmed by longitudinal studies evaluating the various parameters of the periodontal disease.

Background and Aim: The role of collagen fibers in dentin adhesion and hybrid layer has not clearly been established. This study evaluated the effect of collagen removal on the microleakage of four single bottle adhesive systems at resin-dentin interfaces by dye penetration technique.Methods & Materials: This experimental study was performed on 144 class V cavities prepared in buccal and lingual surfaces of human premolar teeth at the cemento-enamel junction with the cervical margin in dentin or cementum and the occlusal margin in enamel. The cavities were etched with 36% phosphoric acid for 15 seconds, rinsed and divided into 8 groups. In 4 groups the cavities were filled with a composite resin using four different dentin adhesive systems [Single Bond, Excite, One-Step, Prime & Bond NT]. In the other 4 groups the acid etched cavities were treated with a 5.25% NaOCl solution to remove the collagen and restored using the same adhesive system and composite resin. The specimens were thermocycled and stored in distilled water at 24oC for three months and were immersed in a 10% solution of methylene blue dye for 72 hours. After rinsing, the restorations were sectioned buccolingually and assessed under an optical stereomicroscope. Microleakage was scored by two independent observers. The data were analyzed by Kruskal Wallis and Dunn multiple comparison tests.Result: Collagen removal resulted in a significant decrease of microleakage for One-Step and an increase for Excite at cervical margin (P<0.001)but did not reduce the microleakage at cervical margins for Prime & bond NT and Single Bond group.Conclusion: Except collagen removal, microleakage of class V composite restoration depends on the type of bonding - system which can be related to fillers, functional monomers or solvent of adhesive systems.

Background and Aim: Immediate diagnosis and treatment is very important in fibrooseous lesion and bone tumor because of complication of these lesions like deformity, paresthesia, dysphagia and death. There was no research project of this matter in Iran. So, it was decided to evaluate the prevalence of fibro-osseous and tumoral lesions of head and neck in Shaheed Beheshti Dental School and Taleghani Hospital.Methods & Materials: This descriptive study was done on the existing data of the 4953 patients referred to the Pathology Department of Shaheed Beheshti Dental School and Taleghani Hospital during 1981-2002.Results: 144 cases of fibro-osseous lesions and bone tumors were collected in this research. Among fibro osseous lesions, fibrous dysplasia was the most prevalent lesion, while among benign bone lesions, osteoma and osteoblastoma and among malignant bony lesions, osteosarcoma had the highest prevalence.Conclusion: Fibrous dysplasia was the most prevalent lesion in females, the second decade of life and in upper jaw.Osteoblastomas were observed in females, in the first and fourth decades of life and in lower jaw. Osteoma was seen mostly in females, in the third decade of life and in lower jaw, while osteosarcoma was prevalent in males, in the third decade of life and in lower jaw.

Background and Aim: Non-reinforced ZOE is the substance that is commonly used in pulpectomy and filling primary teeth canals. Two different ways may be used plugger or lentulo spiral to carry ZOE into the canals. The aim of this study was to compare the degree of microleakage in pulpectomy of primary teeth with each of these two different ways.Methods & Materials: In this experimental study, 44 single rooted primary teeth from maxilla were used based on convenience sampling. First, pulps of all the teeth were removed and all of them were filed. Then all the samples were divided into four groups randomly, two experimental groups each with 20 cases and two smaller groups each with only 2 cases as positive and negative control. In the first experimental group, dental canals were obturated with a thick mix of pure ZOE through condensing with plugger manually. In the second experimental group, dental canals were obturated with a thin mix of ZOE by lentulo spiral. Coronal end of the canals were sealed with Coltosol and most of the root surface was covered with two layers of nail polish and one layer of stick wax, except for 2 mm of apical end of the root. Then samples were immersed in 2% methylenblue and sectioned longitudinally. Finally dye penetration was calculated under a stereomicroscope and results were analyzed by t-test.Result: The mean value of dye penetration (micro leakage) in first group was 2.92 mm and for the second group was about 4.83 mm so that the mean value in the first group was significantly lesser than that of the second group (P<0.001).Conclusion: Because of high viscosity and thickness of ZOE, the hand-held technique (using plugger) had lesser microleakage & better apical seal which could be considered as the preferred technique in filling primary teeth canals.

Background and Aim: This study has been established in order to compare the bond strength of four Iranian artificial teeth - which are produced by Ideal Makoo - and two foreign types of Ivoclar (Liechtenstein & Italy) with denture base resins.Methods & Materials: In this experimental and cross sectional study, 6 teeth from each type ofthe artificial teeth were selected and on the whole, 36 teeth from each type of the artificial teeth were studied. This study was established according to standard ISO 3336, in which 6 stone molds were prepared using a standard brass block and the molds were used to produce 6 acrylic blocks which were each attached to 6 artificial teeth. Each acrylic block was sectioned in to 6 separate samples, so that each sample consisted of an artificial tooth attached to an acrylic part. The samples were tested by Instron 1195- a tension testing machine with the speed of 5 mm/min until fractured. The results were reported in kilogram and were analyzed using the ANOV A statistical test.Results: The results revealed that Liechtenstein Ivoclar had the highest mean bonding force (67.5 11.7 kg) with and Marjan artificial tooth proved to have the lowest mean bonding force (50.3 9.3 kg). It should be noted that the difference of mean strength of Super Brelian and Liechtenstein Ivoclar was only 1 kilogram.Conclusion: Regarding the bond strength, Liechtenstein's Ivoclar would be introduced as the most superior specimen.However, Super Brelian had a very slight difference with Liechtensteins' Ivoclar.

Background and Aim: The oroantral fistula is one of the complications that might occur following extraction of upper posterior teeth. The use of pedicled buccal fat pad graft has recently been considered in the treatment of oroantral fistula. The aim of this article was to evaluate using pedicled buccal fat pad flap for closure of oroantral communications.Methods & Materials: In this experimental study (case series), thirteen patients (11 male & 2 female) with oroantral communications, which either developed following the extraction of maxillary posterior teeth or odontogenic cyst removal, with an average age of 34.06 (24-52 years old), were treated with a pedicled buccal fat pad graft. Surgeries were performed under local or generalized anesthesia. All of patients were evaluated for maxillary sinus infection before and 6 months after surgery with Water's radiography. Clinical repair of wound was evaluated at the first and the second week and 6 months after the operation.Results: Oroantral communication was treated successfully in all patients. Only one patient complained trom pain and nasal obstructions six months following surgery.Conclusion: Pedicled buccal fat pad graft can be successfully used for closure of oroantral communication.

Background and Aim: Restoring endodontically treated tooth with prefabricated post is a well accepted technique with a long history. This article reviews and classifies various prefabricatedposts.Different types of prefabricated posts are available in the market now. These posts are different from each other in installation method, geometric form, surface configuration and material. Each type has it's own advantages and disadvantages. Previously, only metal prefabricated posts in different designs, shapes and surfaces were fabricated by manufacturers. With increasing demand for esthetic restorations, like all ceramic restorations and also for using bonding systems more and more, the need for nonmetallic posts is increased, pushing manufacturers to fabricate ceramic and fiber-reinforced resin posts.Conclusion: A dentist must know about characteristics, advantages and disadvantages of different posts and choose the most suitable type for each case.

Background and Aim: This is an epidemiological study of patterns of condylar fractures. The aim of this study was to assess the incidence and etiology of condylar fractures.Methods & Materials: In this retrospective study, data were obtained by means of special questionnaire regarding age, gender, anatomic site, pattern, causes of injury, treatment modalities and complications. During an 11 years period (1994-2004) 475 patients represented 134 condylar fractures (28.2%) admitted to Dr. Shariati Hospital of Tehran - Iran.Results: Of the 134 patients, 105 (78%) were men and 29 (22%) were women (ratio 3.6:1). Patients' age at the time of injury ranged from 2 to 75 years, with a mean age 24.7 years. The highest incidence was seen in the third decade of life (27.6%). The predominant causative factors in this study was motor vehicle accident (42%) followed by falls and assaults. Most patients (88.8%) were treated by close reduction surgery. The seasonal distribution showed that summer accounted a highest percentage (31%) of all fractures.Conclusion: The condylar fractures included 28.2 percentages of all mandibular fractures in this study. The most common part of condylar fractures was subcondylar site (76.1%). The most common causes were traffic accidents (42.2%). The most common treatment method was close reduction (88.2%). The most common fixation method was maxillomandibular fixation (MMF). Fracture rate in men was more than women (78.4% Vs. 21.6%). The most important associated complications with condylar fractures were ankylosis (2.98%).