Showing 359 results for Ion
L. Eslamian ,
Volume 15, Issue 1 (3-2002)
Abstract
Various comparative studies have been conducted to investigate the effect of functional and fixed appliances in treatment of class II skeletal disorders. The aim of this study was to compare Bionator and Edgewise appliances associated with class II elastics in the treatment of class II skeletal patients, without extraction. Lateral cephalograms of 30 patients (16 girls, 14 boys), 10-13 years old, with class II div I maolocclusion, treated with Bionater and Edgewise appliances were investigated before and after treatment. SNA, SNB, ANB, " to SN, IMP A, mandibular and maxillary lengths, upper anterior facial height to lower anterior facial height, overjet and overbite were measured in each group before and after treatment. The results were analyzed by paired t- test. The magnification of linear measurements were calculated. The differences between variables in 2 groups were compared by t-test. There was no significant difference, regarding age and sex. In both groups, increase in SNB, mandibular length, and IMPA and decrease in " to SN, overjet and overbite and upper anterior face height to lower anterior face height after treatment were statistically significant. Comparing 2 groups before and after treatment showed that increase in SNB and decrease of ANB, overjet and overbite were more in Bionator group than fixed group, which were significant. Decrease in upper anterior face height to lower anterior face height, and increase in IMPA and mandibular length were more in Bionater group but the differences were not statistically significant.
M. Sahebjamei , A. azizi , F. Jamali , N. Marofi ,
Volume 15, Issue 1 (3-2002)
Abstract
Muscular pain is one of the most common causes for facial pain. Myofacial pain dysfunction syndrome (MPDS) is one of the most important disorders of facial area that affected patients suffer from pain, tenderness of one or more masticatory muscles and limitation of movements. Lack of specific and effective therapeutic method, makes it necessary to find a treatment to decrease pain. Considering the analgesic and anti- inflammatory effects of low-level laser, some investigators have recommended it for MPDS patient's treatment. In this study, the effects of low level laser (Ga-Al-As) on MPDS patients referred to dental faculty of Tehran University of Medical Sciences, were investigated. Twenty- two MPDS patents, with mean age 33.32 years, were treated for 4 weeks (12 visits). Clinical examinations were performed in 6 stages. The results of this study showed that variables such as pain severity, cheek pain, pain frequency and tenderness of masseter, temporal, internal and external pterygoid muscles, had a statistically significant improvement at the end of treatment with low level laser (GA-A1-AS) which lasted for three months, (follow- up period). Results of this study showed that, low-level laser therapy has a sedative effect on the pain and tenderness of masticatory muscles in MPDS. Patients and having an accurate and regular program to complete treatment period, has an important role in MPDS improvement.
S. Zarrati , M. Nazari Marzjarani ,
Volume 15, Issue 2 (5-2002)
Abstract
Esthetic is a natural necessity among all human beings, and the reconstruction of the natural features of prosthesis is considered an important aspect in dentistry. Reconstruction of the natural features in removable prosthesis by characterization of denture base is one of the most important factors. In this regard esthetic, in removable prostheses, is achieved through different techniques such as: tooth selection and arrangement, designing the denture base and acrylic base color. The final goal for ail these effects is to achieve a natural appearance for denture. However, other factors such as treatment limitations, different personal needs and general health principles, should be taken into consideration. This article not only reviews the natural appearance of oral mucosa that is replaced by the denture base, but also discusses about the materials used in tinting acrylic denture base and their application techniques.
A. Monzavi , S. Mir Mohammad Rezaei , H. Bajelan ,
Volume 15, Issue 2 (5-2002)
Abstract
Waxes have a lot of applications in dentistry. Such materials are of thermoplastic type that undergoes deformation in different temperatures. Two important properties of base plate waxes are flow and their coefficient of linear thermal expansion. Recently, different institutions, inside the country, produce dentistry waxes, while they have not been standardized. Consequently, consumers' dissatisfaction are observed. In this research, the two above- mentioned factors were compared between three kinds of Iranian waxes with Cavex that is foreign production, based on test number 24 of ADA. To measure the flow rate in the temperatures of 23, 37 and 45°c, Wilcoxon statistical analysis was used. The results showed that in 23°c, the flow rate of Cavex and Azardent waxes met ADA standards however, it was not true for two others types. In 37°c, the flow of none of the waxes was standardized and in 45°c their flow was acceptable, moreover, thermal expansion coefficient, for Cavex and Azardent types, was based on ADA standard.
M. lotfazar , Sh. Faghihi ,
Volume 15, Issue 3 (6-2002)
Abstract
There are many researches evaluation different methods for covering the root surface. In the most of these studies, type I and II of Miller treatment had been searched. The purpose of this study was a comparison between connective tissue graft (CTG) and guided tissue regeneration (GTR) with a collagen membrane in the treatment of gingival recession defects (Miller class III). Six patients, each contributing a pair of Miller class III buccal gingival recessions, were treated. The clinical measurements were obtained at baseline and 1,2,4,6,12,18 months after surgery. Statistical analysis were performed using paired t-test between periods (baseline versus 6 months and baseline versus 18 months) within each treatment group and also between treatment groups before treatment and 6, 12 and 18 months after the treatment. The treatments were compared by a triple analysis of variance along the time (treatment, patient, time). Both CTG and GTR with a bioabsorbable membrane demonstrated significant clinical and esthetic improvement for gingival recession coverage. The CTG and GTR procedures had mean root coverage of 55% and 47.5% respectively, in the end of study. The CTG group was statistically better than GTR for recession depth, recession width and keratinized tissue width. Also, passing the time (18 months) as a distinct factor of treatment procedures was effective in increasing of clinical attachment level and keratinized tissue width.
Mh. Fathi , V. Mortazavi , Sb. Moosavi ,
Volume 15, Issue 3 (6-2002)
Abstract
Nowadays, application of implants as a new method for replacing extracted teeth have been improved. So, many researches have been performed for improving the characteristics of implants. The aim of this study was to design and produce a desired coating in order to obtaining two goals including improvement of the corrosion behavior of metallic endodontic implant and the bone osseointegration simultaneously. Stainless steel 316L (SS), cobalt-chromium alloy (Vit) and commercial pure titanium (cpTi) were chosen as metallic substrates and hydroxyapatite coating (HAC) were performed by plasma-spraying (PS) process on three different substrates. A novel double layer Hydroxyapatite/Titanium (HA/Ti) composite coating composed of a HA top layer and a Ti under layer was prepared using PS and physical vapor deposition (PVD) process respectively on SS. Structural characterization techniques including XRD, SEM and EDX were utilized to investigate the microstructure, morpholgy and crystallinity of the coatings. Electrochemical potentiodynamic tests were performed in physiological solutions in order to determine and compare the corrosion behavior of the coated and uncoated specimens behavior as an indication of biocmpatibility. Results indicated that the cpTi possesses the highest and SS the lowest corrosion resistance (highest corrosion current density) between uncoated substrates. This trend was independent to the type of physiological environment. The HA coating decreased the corrosion current density of HA coated metallic implants but did not change that trend. HAC acted as a mechanical barrier on the metallic substrate but could not prevent the interaction between metallic substrate and environment completely. The HA/Ti composite coating improved the corrosion behavior of SS. The corrosion current density of HA/Ti coated SS decreased and was exactly similar to single HA coated cpTi in physiological solutions. The results indicated that HA/Ti composite coated SS could be used as an endodontic implant and two goals including improvement of corrosion resistance (biocompatibiiity) and bone osseointegration could be obtained simultaneously.
Sa. Miremadi , Ar. Rokn , A. Nikbakht ,
Volume 15, Issue 4 (1-2003)
Abstract
In the past two decades, replacement of the missing teeth with implant borne prosthesis has become a treatment modality, accepted by the scientific community for fully and partially edentulous patients. The aim of the present study is to evaluate retrospectively, 502 ITI dental implants application, in partial and complete edentulous patients, treated in two private centers, based on clinical and radiographic parameters.One hundred and forty patients, with 502 ITI dental implants, who were treated from 1994 to 2000 in two private centers, were investigated. For such patientsT a minimum of one year and a maximum of six years were passed since prosthesis placement over implants, so they were cooperative subjects. There was a significant relation between implant type and bone loss, so was between the presence and absence of BOP and the rate of bone loss. From totality 502 implants, 6 implants (28%) and 4 implants (1.4%) were lost, in maxilla and mandible, respectively. The total success rate was 98%. This rate, in maxilla with 212 implants was 97.2% and in mandible with 90 implants was 98.6%. The mean value of bone loss (RBL) and periodontal pocket depth (PPD) during 6 years, for the remaning 492 implants were 0.93±0.39mm and 1.99mm, respectively. The results showed that ITI dental implants, with a success rate of more than 97%, can be used as a desirable treatment choice in partial and complete edentulous patients.
B. Ajami , N. khadem ,
Volume 15, Issue 4 (1-2003)
Abstract
Determination of puberty age of girls have been the research subject of researches and jurisprudents. The aim of this study was to investigate the relationship between tooth eruption and puberty in 12 year - old girl students. This cross-sectional study was conducted on 300, 12-year-old girl students in Mashhad, selected randomly. For each subject, a questionnaire was completed, including the information about the eruption rate of the teeth number 3,4,5,7 and the first menstruation, as puberty index to analyze the results, Mann Whitney test was used. The results of this study showed that, from among 300 female students, just 25% of them attained puberty at the age of 12.On the other hand, a direct relationship was observed between puberty and complete eruption of the second right maxillary molar and the first and second left mandibular premolars, which was statistically significant.
M. Zarrabian, N. Barfehi ,
Volume 16, Issue 1 (4-2003)
Abstract
Statement of Problem: Different materials have been suggested for endodontic surgeries. One of the most important characteristics of filling materials is their biocompatibiiity.
Aim: The aim of this research was to evaluate the biocompatibiiity of four different root end filling materials.
Material and Methods: In this study, 20 male Guineanpigs from English short hair breed, weighing 600-700 grams, were selected. The animals were classified into two groups. In the first group, amalgam and composite and in the second group MTA and Glass Ionomer were examined. The testing materials were shaped into cylindrical form with 1 mm diameter and 1.5 mm height. After general anesthesia, two
cavities with 1mm diameter and 2 mm depth were prepared in parasymphysis area of animal jaw. The prepared materials were implanted in these cavities and the flaps were sutured. After 80 days, the animals were sacrificed and the dissected bones, with implanted materials inside them, were sent for histological evaluation. The histological findings were statistically analysed by Kruskal Wallis and x'tests.
Results: No significant differences were shown in the degree of inflammation, the type of inflammatory cells adjacent to the tested materials and the type of tissue response, induced in the vicinity of these four materials during 80 days.
Conclusion: Regarding biocompatibiiity, there was no significant difference among amalgam,composite, MTA and glass Ionomer in endodontic surgeries.
A. Zarifkar , H. Skandaryan , M. Mokhtary , J. Ay ,
Volume 16, Issue 1 (4-2003)
Abstract
Statement of Problem: Eugenol is the most important chemical compound of the clove tree (Eugenia aryophylata) extract. That is widely used in dentistry as a bactericidal and pain relieving agent.
Aim: The aim of the current study was to evaluate the antinociceptive effect of local and systemic administration of eugenol by formalin test in rats.
Materials and Methods: In this research, 56 male Wistar rats, weighing 230±20 g were divided into seven groups (n=8). Ten minutes before formalin test, different doses of eugenol (12.5,25,50 mg /in groups 2,3,4 respectively) were injected to the right hind paw of the rats subcutaneously. In- group 5 eugnol (50 mg) was. injected to the contralateral hind paw. In group 6 eugenol (100 mg/ kg) and control group (group 7), equal volume of norma! saline was injected intraperitonealy . The minutes 0-5 and 16-60 were considered as acute and chronic phases of pain in the formalin test, respectively. Data were statistically analyzed by ANOVA and Tukey's tests.
Results: The results showed that local injection of eugenol to the same paw receiving formalin caused a decrease of nociception in both acute and chronic phases of formalin test (PO.005). However, in the group that eugenol (50mg/ kg) was injected to the contralateral paw, no significant differences were observed in the pain score in comparison with the control group. Intraperitoneal injection of eugenol (lOOmg/kg) did not reduce the nociception in the acute phase, but it caused a significant decrease of nociception in tonic phase (PO.00I).
Conclusion: It was concluded that eugenol, as a local anesthetic drug not only inhibits nociceptive impulse conduction on the peripheral pain fibers, but also centrally reduce chronic pain.
M. Ghavamnasiri , Saa. Hosseini , H. Farzaneh ,
Volume 16, Issue 1 (4-2003)
Abstract
Statement Problem: A few studies have been conducted about bioglass posts.
Aim: The aim of this study was to compare bioglass posts with prefabricated metallic posts in clinical performance of extensive composite restorations for anterior endodontically treated teeth.
Materials and Methods: Sixty endodontocally maxillary anterior teeth, with horizontally or vertically destruction, were selected. Teeth were divided into two groups based on the kind of post: Metallic prefabricated parapost and bioglass post. Each group was divided into three subgroups based on anterior bite: normal, deep bite and edge to edge. Gutta-percha was removed from 2/3 of canal length for parapost and 1/3 for bioglass post. After etching with phosphoric-acid (37%) and applying dentine bonding syntac, Duo cement was used for the adhesion of bioglass post and a self cured composite (Degufil) for parapost. Restoration was done with a hybrid composite (Heliomolar). Follow up studies, radio-graphically and clinically, were done every three months for a 1.5-year period. Exact Fisher and Pearson tests were used for data analysis.
Results: Apical lesion was not observed in any of the radiographs. Post seal was increased by resin cement and dentin bonding agent. Post type did not significantly affect on the clinical success rate of the restorations. The retention of restoration, for both posts, was the same. Crown destruction had no significant effect on success rate. The type of anterior bite had a significant effect on success rate, as the total 6.6% failure rate was related to the patients with anterior deep bite.
Conclusion: It is suggested to use metallic paraposts and bioglass posts, in extensive composite restorations for patients with deep-bite, more conservatively.
M. Mortazavi , Z. Bahrololoomi ,
Volume 16, Issue 1 (4-2003)
Abstract
Statement of Problem: Microleakage presents the major cause for restorations failure in the oral cavity resulting in postoperative sensitivity, pulp irritation and secondary caries formation.
Aim: The aim of this study was to compare two dentinal adhesive systems of fifth generation and copalite varnish in reducing microleakage of amalgam restorations in primary teeth.
Materials and Methods: In this in-vitro study, 100 class V amalgam restorations were prepared on the buccal or lingual surfaces of primary molar and canine teeth. Samples were randomly divided into four groups (25 samples each). No liner was used for the first group and the second group restorations were lined with copalite varnish. Two dentin adhesives, called Syntac C and Single Bond, were used for the third and fourth groups, respectively. At the next stage, the samples were immersed in 5% fuschin solution for 24 hours, then sectioned buccolingually, and examined under a stereomicroscope for microleakage evaluation.
Results: There was a significant difference between four groups statistically (PO.000I), Comparing four groups, the first and fourth ones, demonstrated the most and the least microleakage, respectively.
Conclusion: The present study showed that new dentinal adhesive systems caused microleakage reduction in amalgam restorations of primary teeth.
F. Fallahian ,
Volume 16, Issue 2 (5-2003)
Abstract
The health of habitants, living in un-fluoridated drinking water areas, can be endangered through fluoride intake from food, beverages, tooth paste and dentistry products. Fluoride is used in mouthwash, toothpaste, juice fruits, conserved foods and Teflon dishes. Water exposure to fluoride occurs through fertilizers, aluminum industries, insecticides, pesticides, herbicides and fungicides used for fruits and vegetables which ultimately lead to environmental fluoride pollution. Some side effects.caused by chronic fluoride intake are as follows: decrease of hemoglobin concentration, gastrointestinal disorders, and tooth loss at young age, osteofluorosis, hip fracture among aged people, osteosclerosis,osteoporosis, special forms of arthritis and joint ankylosis, metaphysial osteomalacia, mottling and weak structure of tooth, insulin secretion and glucose tolerance test disorders, decrease of urine concentration,immune system disorders, genetic defects and cancer, learning disabilities and IQ(intelligence quotient)deficits and thyroid dysfunction The present article was to investigate the side effect of excessivefluoride intake and to discuss different preventive and diagnostic ways.
H. Afshar , B. Seraj , A. Emadosadati ,
Volume 16, Issue 2 (5-2003)
Abstract
Statement of Problem: Previous experiences and clinical observations indicate that enamel hypoplasia and hypocalcification of first permanent molars, among infants born in Cessarian Section Delivery (C/S) is more common than those born in Normal Vaginal Delivery (NVD). Moreover, the first permanent molar is the only tooth that its "cusp tip calcification" starts exactly at the time of delivery.
Purpose: The aim of this research was to investigate the relationship between delivery type and clinical feature of the first permanent molar. Meanwhile, the different effects of the elective and selective types of cessarian, on the clinical feature of first permanent molar, were studied.
Materials and Methods: Birth files, relation to the year 1994 and before, were extracted from a gynecologist clinic. One hundred patients with NVD, 50 patients with selective cessarian delivery and 50 patients with elective cessarian delivery were chosen to examine clinical feature of the first permanent molars of their children. The children, 6 years old or more, were examined. The medical information of the mother were extracted from her file and that of child, were asked from the mother. To analyze the result, X lest- was used.
Results: The prevalence of enamel defects (hypoplasia and hypocalcification) of the first permanent molar among children born by C/S, were significantly different from the children born by NVD (P=0.0002). Mean while, the prevalence of these enamel defects in the selective cessarian delivery was more than elective cessarian delivery (17% vs. 9%), which was not statistically significant (P-0.07)
Conclusion: It is suggested that gynecologists, pediatricians and pedodontists provide the parents with necessary information about the child's first permanent tooth and ask them to pay enough attention to keep this tooth which is considered as the key of occlusion.
M. Hassani Tabatabaei , M. Ataei , H. Safar Charati ,
Volume 16, Issue 2 (5-2003)
Abstract
Statement of Problem: Recently, investigators have presented new methods to reduce polymerization shrinkage of composite resin restorations. It is claimed that more powerful light cure systems associated with a change in radiation patterns, lead to improved mechanical properties and reduced microleakage.
Purpose: The aim of the present study was to evaluate the effects of two curing systems, known as Soft-Start, Pulse-Delay, on microleakage and degree of conversion of composite resin restorations.
Materials and Methods: To evaluate microleakage, dye penetration method in class V cavities was applied. 30 extracted human molars filled with three different curing techniques, namely conventional, Soft-Start and Pulse-Delay, were compared. Degree of conversion was measured by FTIR Spectroscopy method immediately after sample curing. Kruskal- Wallis and Mann-Whitney test were used to compare groups.
Results: The degree of microleakage in enamel and dentin among three groups was not significantly different, however, microleakage in gingival and occlusal walls showed a significant difference among Pulse-Delay curing (P=0.001) and Soft-Start curing (P=0.28) groups, meaning that leakage gingival in wall was significantly higher than occlusal wall. This difference was not significant in conventional group. Moreover, the degree of conversion was not statistically significant among three groups (P-0.909).
Conclusion: Soft-Start and Pulse-Delay curing systems, with a two intensity start curing light, do not provide better marginal adaptation in class V composite resin restorations. It should be mentioned that polymerization degree is not also reduced in these methods.
J Fariaby ,
Volume 16, Issue 3 (5-2003)
Abstract
Distraction osteogenesis (DO), firstly introduced to the medical world by Russian scientist Ilizarov for long bone lenghtening in orthopedics can be considered as an appropriate substitute in the treatment of maxillofacial deformities. Natural events occuring during the repair of a fractured bone segment not only lead to the desired bone length but also prevent from the undesired disadvantages of osteotomies and bone grafting. Recently a lot of investigations have been conducted to evaluate the efficacy of DO in the treatment of maxillofacial deformities, which in some cases have lead to successful results. In the present article a lot of issues in maxillofacial surgery and different treatment goals associated with DO are discussed.
H. Razmi , A . Yousefi ,
Volume 16, Issue 3 (5-2003)
Abstract
Statement of Problem: The goal of a successful endodontic surgery is to establish an adequate seal in apical region. Therefore during surgery, root-end resection is essential for an appropriate situation and proper access.
Purpose: The aim of this study was to determine the most appropriate root-end resection angle to establish adequate apical seal in periapical surgery
Materials and Methods: Forty-five intact extracted human maxillary central incisors were randomly divided into three 15-tooth groups. The root canals were instrumented and then obturated using lateral condensation technique. AM roots were resected at 3mm from apical portion. Angles of root resection for each group were 0, 30 and 45 degrees. Then all teeth surfaces, except the cut ones, were covered with nail polish and immersed in methylen blue for 7 days. After 7 days, nail polish was removed from the surfaces and samples were split in buccolingual direction. Then, dye penetration (mm) was measured using a stereozoom microscope (Loupe) [X4 magnification] and eye lens. In order to analyze the data, unilateral variance analysis was used.
Results: The values of dye penetration were: 7.23±3.34 (0°), 8.46±3.01(30°) and 9.74±4.11 (45°). There
was no significant difference between three groups (P>0.05).
Conclusion: It is suggested that the angle of root-end resection put a limited effect on apical seal if retrograde cavity depth is increased.
M. Pangnoosh , H . Bashizadeh Fakhar ,
Volume 16, Issue 3 (5-2003)
Abstract
Statement of Problem: Computer Sciences, in radiology, like other fields, is of high importance. It should also be noted that the accuracy of the technique and work conditions affects the radiographs information considerably. There for, in order to get more accurate diagnostic information, it seems necessary to investigate different digitized radiographic techniques and to compare them with the conventional technique.
Purpose: The aim of this study was to compare the accuracy of conventional and digitized radiographic images by three digitization techniques in proximal caries detection.
Material and Methods: In this research study, sixty extracted human canines, premolars and molars were mounted in blocks and imaged on E-Kodak film, similar to bitewing radiographs. Ten bitewing radiographs were then scanned at 600 d.p.i with flat bed scanner and a digital camera, then digitized at 300 d.p.i with another digital camera. The digitized images were displayed randomly on a high-resolution monitor. Six
observers assessed the caries status of 120 proximal surfaces by conventional and digitized images. The observer's scores were compared with the results of the macroscopic examination. Reliability of each technique was calculated. Data were analyzed using chi-square and ANOVA tests.
Results: No significant differences were detected between different techniques in intact proximal surfaces and enamel caries diagnosis. However, digital techniques were more sensitive in dentin caries detection (P<0.05).
Conclusions: When conventional film images are digitized, medium resolution (300 d.p.i) seems to be sufficient. At this resolution the file size is decreased and there is no significant loss of the information necessary for caries diagnosis.
B. Eftekhar ,
Volume 16, Issue 4 (1-2004)
Abstract
The use of root canal models in endodontics education is of high importance. So, in this article a new method is presented that the students can produce these models with simple and low cost instruments.These plastic models are made of polyester which is low cost, available and has the approximate cutting properties of dentin. The best molds were disposable syringes due to their low cost, availability and producing smooth surfaces on polyester models. A spreader with desired curve and tapering is used for producing canals. Rockwell A hardness coefficient of polyester is "33", which is near dentin "31" and foreign made models "35.5". Since these polyester models can tolerate up to 280°C and have acceptable resistance to chloroform, all root canal therapy techniques such as vertical condensation and retreatments are practicable. Their transparency encourage the students to work on them. As a result, the use of these models is recommended for endodontics training.
M. Zarabian , M.h. Nekoofar , Bs. Marashi ,
Volume 16, Issue 4 (1-2004)
Abstract
Statement of Problem:Various methods have already been suggested to measure the working length in root canal therapy among which the use of paper point, tactile sense, radiography and electronic apex finder instruments can be named. Investigations on EAL (Electronic Apex Locator) indicate that these instruments can reduce the number of required radiography to a great extent. Moreover, in special cases such as patients with high risk reflex, pregnant women, the mental disabled and handicapped and also in cases with special anatomical structures these instruments are proper substitutes for radiography.
Purpose: The aim of this study was to compare the accuracy of an Iranian made apex finder instrument with Neosono Ultima EZ and radiography.
Materials and Methods: This study was conducted on 51 mandibular molars, devoid of calcification, internal and external resorption, severe root curve or fracture, which were extracted due to periodontal disease or severe caries. All the specimens were washed in 2.5% hypochlorite sodium and washing with water, kept in 10% formalin solution, under room temperature.
Results: The accuracy of the Iranian instrument was measured (81.8%) similar to that of radiography (81.2%). But the accuracy of Neosono Wtima EZ was (92.9%) which was higher than the two other methods.
Conclusion: No statistically significant difference was found between Neosono Ultima EZ instrument and two other groups, using SPSS 10 statistical soft ware.
