Journal of Mashhad Dental School
Year:2005 | Volume:29 | Issue:1-2|Papers Count:22

Introduction: Establishing vertical dimension of occlusion (VDO) or vertical relation of jaws is one of the important factors in prosthetic treatment procedures for edentulous patients. It is usually done in mandibular rest position which in turn is affected by different factors such as loss of teeth, patient age and amount of bone resorption after being edentulous, and also the method for determination of VDO (relaxation, swallowing, phonetic...), and patient position.The aim of this study was to evaluate the adjustment of VDO determined by dentists compared with that of swallowing and phonetic methods, and anthropometric measurements.Materials & Methods: In a descriptive analytical cross-sectional study, one hundred 31-50 year old edentulous patients reffering to clinics and private offices in Babol were selected in cluster sampling. VDO was determined in patients by speech and swallowing methods. Also distances of external corner of eye to tragus of left ear, pupils to lip corner, glabella to subnasal, and distance between tips of thumb to tip of pointing finger were evaluated in two sessions by two independent observations using electronic digital caliper. The VDO obtained through these measurements was compared with the exiting one determined by dentist. The data were analyzed using SPSS 10.5 software (T-test). Results: Mean existing VDO (subnasal to submental) was 73.49mm±7.9 while a VDO of 76.59mm±5.46 was obtained via swallowing and 75.89mm±5.34 via speech methods. The difference was significant (P<0.05). A significant correlation was detected between both the VDO determined via speech and swallowing and either external corner of eye-tragus and pupil-lip corner distances (P>0.05).Conclusion: It seems that most of the dentists consider a shorter VDO for complete dentures.  

Introduction: Heavy metals absorbed systemically due to therapeutic use or occupational environments may discolor the gingival and other areas of the oral mucosa. The purpose of this study was to determine the prevalence of oral and gingival pigmentations and blood lead level among battery industry workers and the relationship between them.Materials & Methods: In this cross-sectional study, fifty battery industry workers at Mashhad and Sabzevar were examined clinically regarding oral and gingival pigmentations. Then blood test was done for each of them and blood lead level was measured by graphite furnace atomic absorption technique at Imam Reza hospital laboratory. The data were analysed using chi-square test.Results: In this study, there was not any significant difference between mean blood lead level of the workers of battery industry and that of the general population. Also, no significant changes in their oral pigmentation stata were detected clinically.Conclusion: It seems that due to new technologies in battery industry, saturnism among workers and other lead effects such as oral pigmentation (lead line) are not significant and their blood lead level is within the normal range.

Introduction: Regarding the manufacture of different gutta-percha cones and the importance of apical seal in a successful root canal therapy, this experimental study was designed to compare the invivo effects of Ariadent gutta-percha with Roeko and Diadent.Materials & Methods: In this exprimental invivo study, 29 mature Albinus rats (mean weight 202/77 gr) were selected. Four intradermal incisions were made in the dorsal part of each rat. In three incised areas, a piece of each gutta-percha was placed and one of the four incised areas was assumed as the negative control.Animals were sacrificed at 15, 30 and 60 day intervals and then specimens were taken from subcutaneous connective tissues of rats. All of the specimens were prepared histologically and stained using H & E staining method. Histological assessment was based on the number of inflammatory cells. Data were analysed using one- Way ANOVA and Duncan test with 95% confidence level through SPSS software.Results: The results revealed that Ariadent gutta-percha in 15 day interval was more reaction inducing than Roeko and Diadent but in 30 and 60 day intervals, tissue biocompatibility of Ariadent was the same as Roeko and Diadent. Conclusion: Iranian Ariadent gutta-percha can be considered as a substitute for other foreign gutta-percha cones.

Introduction: Considering the influence of functional matrix on the morphogenesis of jaws and teeth, it is essential to accept that functional forces will cause a change in tooth position and bone formation.The purpose of this research was to study the dental and skeletal effects of maxillary protraction following the use of tongue guard myofunctional appliance in children with class III malocclusion with maxillary deficiency. Materials & Methods: Pretreatment and post treatment lateral cephalograms from 23 patients (11 male and 12 female) with mean age of 8.77 years treated by tongue guard myofunctional appliance in orthodontics clinic of Mashhad Dental School were traced and analyzed. Average treatment time was 6 months. Differences between before treatment (BT) and after treatment (AT) values were analyzed using SPSS statistical software (paired T.test).Results: The results were as follow:1. A highly significant anterior movement of maxilla occurred with increases in SNA (with mean=l degree) and ANB (with mean=0.96 degree) angles and anterior movement of A point in Wits analysis (P=0.001).2. Maxilla/Mandible ratio (according to A.M. Schwarz) increased (P=0.001).3. The maxillary incisors moved in anterior direction.4. The mandibular incisors moved posteriorly. In other words, IMPA decreased (P<0.05).5. Profile convexity increased and Soft tissue profile and upper lip area improved.Conclusion: The results of this study indicate that use of tongue guard myofunctional appliance is appropriate for patients initially presenting with anteroposterior and vertical maxillary deficiency.  

Introduction: Hepatitis B is a primary viral infection of liver which is of high importance, clinically as well as socioeconomically, due to its capacity in producing chronic state. One of its significant routes of transmission is blood and contaminated fluids, items and surfaces with blood. Since health care workers are always in touch with patient's blood and their blood contaminated secretions, they are considered as high risk groups. Thus, their knowledgibility toward hepatitis B and its routes of transmission is important. The purpose of this study was to determine the knowledge rate of health care workers (apart from dentists) toward hepatitis B at Mashhad Dental School.Materials & Methods: In this descriptive study, all of the health care workers apart from dentists at Mashhad dental school were given a questionnaire concerning hepatitis B complications, its routes of transmission and methods of prevention. Totally, 170 questionnaires were analyzed using SPSS statistical software.Results: The nurses had the highest rate of knowledge. 16.6% had an agreeable knowledge about routes of transmission, 33/3% about complications and 50% about the methods of prevention. The servants had the lowest rate of knowledge, more than 90% of whom had little or very little knowledge about routes of transmission, complications and prevention methods (94%, 93% and 95/5% respectively). None of them had an agreeable knowledge state about n any of the studied variables of hepatitis B.Conclusion: This study revealed that the rate of knowledge increased with level of education. The nurses had the highest education and rate of knowledge and the servants had the lowest education and rate of knowledge. Although health care workers were more knowledgeable about preventive methods than complications and transmission routes, a number of them had not been vaccinated against hepatitis B. This implies that the health care worker's commitment toward hepatitis B is not at an agreeable state and necessitates continuous educational strategies as well as supervision over their practice.  

Introduction: The purpose of this study was to evaluate the incidence of postoperative bleeding in patients treated with oral anticoagulant medication undergone dental extraction without interruption of medication and to compare the incidence of postoperative bleeding with International Normalized Ratio (INR) value. Materials and Methods: This study was a cross sectional study and the data collecting method was direct observation. A total of 362 patients undergone 703 dental extractions without interruption of oral anticoagulant medication were studied. For all patients INR value was measured on the day of surgery and based on INR value, the patients were divided into three groups: Group I with INR of 1.5-2.49, Group2 with INR of 2.5-3.49, and Group 3 with INR of> 3.5. Dental extraction was carried out by two surgeon and if necessary, local hemostatic agents were applied (gelfoam and multiple silk sutures).The data were analyzed using SPSS 11.5 statistical software (Willcoxan and Mann-Whitney tests).Results: Of the 360 patients undergone oral anticoagulant medication, in 30 patients postoperative bleeding occurred. 11 patients (7.43%) in group one, 10 patients (8.62%) in group two and 9 patients (9.18%) in group three, developed postoperative bleeding.Conclusion: The incidence of postoperative bleeding was not significantly different in three groups. Thus simple dental extractions can be performed without modification of oral anticoagulant therapy. Local hemostasis using gelfoam and sutures would be sufficient to control postoperative bleeding.

Introduction: The aim of this study which was done for the first time in Iran, was the assessment of chromosomal abnormalities in patients with oral cancer.Materials & Methods: For clinical, epidemilogic and probable chromosomal abnormalities evaluation, 45 patients with oral cancer were selected from patients referred to oral disease department of Mashhad dental school and Emam Reza, Ghaem and amid hospitals.We performed clinical examination and biopsy for confirming diagnosis of oral cancer. After pathology confirmation, two blood samples (containing EDTA and heparin) were prepared from patients who had not received any treatments (radio therapy, chemical therapy or antibiotic therapy) during the previous two weeks. Heparinized blood samples were transported to genetic laboratory for cell culture.Results: Cell culture of 30 patients was done successfully and the other 15 which failed, were excluded from the study. In Karyotype examination, no chromosomal abnormalities were detected in these patients. Conclusion: Minor chromosomal disorders can not he studied through current available procedures in Iran and FISH system which makes further studies available, had not been put into practice in Iran so far. Molecular genetic study and gene isolation can help in detecting gene effect on oral cancer.  

Introduction: The purpose of this study was to evaluate the prevalence of different types of dental malocclusions in the city of Neishabour.Materials and Methods: In this descriptive- cross sectional study, 469 students (215 girls and 254 boys) with ages ranging from 12 to 15 were randomly selected among 20130 junior high school students in the city of Neishabour. The colossal characteristics of these students including profile situation, molar and canine relationships on the basis of Angle classification, over jet, overbite, and the type of malocclusion, were recorded on data sheets. To compare the results between boys and girls, chi-square test was used. To compare the results of this study with other studies, Z statistical test was used. A confidence level of 95% was considered in this study.Results: The results of this study indicated that 13.7% of samples had normal occlusion, while 54% had class I malocclusion, 16.4% had class II Div 1 malocclusion, 6.8% had class II Div 2 malocclusion, and 9.2% demonstrated class III malocclusion. Except in overbite and anterior openbite (which revealed more reduction in boys), there was no significant difference in other types of malocclusions between boys and girls.Conclusion: Only 13.7% of the sample population had normal occlusion, and the remaining 86.3% had some type of malocclusion. Therefore considering the high prevalence of malocclusion, care should be taken for prevention and on time treatment schedules.

Introduction: Most microorganisms can migrate from the oral cavity to other parts of the body. Besides, poor oral hygiene can cause oral and dental problems as well as systemic diseases. The purpose of this study was to evaluate oral hygiene in high school students in total and according to sex in various geographic districts of the city of Mashhad.Materials and Methods: In this cross sectional study, the data Collecting method was direct observation using informational form. In this study, 906 cases (416 girls and 490 boys) with 15-18 years of age were selected in random cluster sampling. Use and Sinless Gingival index (01) and Sinless and Loe plaque index (PI) were used and oral hygiene status was categorized into four groups as follow:Score 0: Normal gingiva (Oral hygiene was good)Score 1: Mild inflammation in gingiva ... (Oral hygiene was moderate)Score 2: Moderate inflammation... (Oral hygiene was poor)Score 3: Severe inflammation... (Oral hygiene was very poor)Data were analyzed by SPSS software and chi-square test and likelihood ratio statistic were used for statistical analysis.Results: 1. 26.4% of the students had good oral hygiene, 59.5% had moderate oral hygiene and 17.1% had poor oral hygiene stata. No cases with very poor oral hygiene were observed.2. Oral hygiene status in girls was better than boys (P-v=0.000) 3. There was a significant relationship between oral hygiene and geographic district (P-v=0.003). This relationship was also significant in girls (P-v=0.003) and boys (P-v=0.000).4. A significant difference in oral hygiene status was detected between areas with good and poor socio- economic stat a (P-v=0.000).Conclusion: Moderate oral hygiene had the highest rate and poor oral hygiene had the lowest rate. Oral hygiene in girls was better than that of boys and difference in oral hygiene among districts with better sodo-economic condition and poor socio-economic condition was significant. Oral hygiene was significantly affected by sex. Oral hygiene was significantly related to various geographic districts in total, and also in boys and girls.  

Introduction: The purpose of this study was to evaluate the marginal porcelain extension on microleakage of base metal - porcelain crowns when four types of luting cements have been used for cementation.Materials & Methods: In this invitro experimental study, ninety six base metal-porcelain crowns with three types of finishing margins were made for premolars. Then they were luted with four different luting cements (zinc phosphate, zinc polycarboxylate, glass ionomer and Panavia F). Next, they were thermocycled (1000 times). Finally, the microleakage was measured after dye penetration.For data analysis, Non parametric Kruskal-Wallis and Mann-Whitney tests were used (a=0.05). Result: 1. The mean rank of microleakage in buccal margin was more than lingual one (P<0.05).2. In all of the finis4ing margins, zinc phosphate cement showed the highest microleakage in buccal and lingual walls (P<0.05).3. In all of the finishing margins, Panavia F showed the least microleakage compared to the other cements in two walls (P<0.05).Conclusion: For promotion of marginal seal in base metal - porcelain crowns, the use of Panavia F as a luting cement is suggested.

Introduction: The purpose of this cross sectional study was to evaluate the local and systemic disturbances due to teething in 6-36 month old babies in the city of Mashhad.Materials & Methods: In this cross- sectional study, 116 babies, consisting of 61 boys and 55 girls, 6-36 months old, were examined for local and systemic disturbances. Using SPSS software, Chi-square test, Fisher's exact test and Wilcoxon rank test were used for data analysis.Results: Among the systemic manifestations, fever was the most frequent disturbance (76.7%) and vomiting was the least frequent one (9.5%). Among local symptoms, swelling and redness of gums was the most frequent disturbance (63.8%) and eruption hematoma was the least frequent disturbance (0.9%). Frequency of local manifestations was higher than systemic ones (P=0.002%).Conclusion: Although teething is a physiologic process, it can be accompanied with some symptoms and disturbances which are mostly local (drooling, swelling and redness of gums...) as well as some systemic symptoms (restlessness, loss of appetite...). However, severe systemic disturbances such as high fever and acute gastrointestinal disorders may not be attributed to teething and should be evaluated for etiology and proper treatment.

Introduction: Dental plaque and periodontal pockets might be a reservoir for helicobacter pylori which is a factor for recurrence of alimentary system problems. The aim of this study was assessment of helicobacter pylori in dental plaque, periodontal pockets and stomach samples of patients with dyspepsia.Materials and Methods: In this descriptive study, 96 patients (45 Males & 51 females) referred to Ecbatan hospital with dyspeptic complaints, were randomly selected. After filling out the questionnaire, samples of subgingival plaque and periodontal pocket were prepared in every patient. Then the patients were examined by endoscopy. All the samples were collected and were assessed for detection of helicobactor pylori (HP) by polymerase chain reaction (PCR).Results: In 96 of dyspeptic patients with mean age of 37.28 yr, negative PCR in all samples was detected.Conclusion: It can be concluded that dental plaque and periodontal pockets could not be a reservoir for HP, and do not play a role in recurrence or incidence of dyspepsia in these patients.

Introduction: Neonatal period is the first developing phase after birth follow by different developmental processes up to the age of puberty. A neonate may be born with different oral lesions. The aim of this study was to evaluate oral lesions in new burns at Mashhad Imam Reza Hospital.Materials & Methods: In this cross - sectional descriptive study, 600 newborns were observed during 2.5 months in 2001. Total oral cavity, including soft palate, hard palate, tongue, alveolar ridge and oral cavity floor was examined with tongue blade and light.Results: Results showed that 52.6% of new borns (316 cases) had oral lesions. 0.66% cases had natal and neonatal teeth, 0.5% cases had congenital epulis, 1.8% cases were with ankyloglossia, 41.5% cases with Epstein's pearls, 22.3% cases with Bohn nodule and 0.16% case with exostosis. There were no cases with cleft lip or cleft palate. The most frequent oral lesion observed was Epstein's pearls.Conclusion: Our study showed that prevalence of natal teeth in the city of Mashhad was more than other countries except for Bohn nodule and Epstein's pearls which occurred less frequently than other countries.

Introduction: The quality of dental unit water is of considerable importance since patients and dental staff are regularly exposed to water and aerosols generated from the dental unit. Following ADA instruction, this study was performed to control the contamination of Dental Unit Water Line (DUWL) to less than 200 CFU/ml. The purpose of this study was to evaluate the microbiology of DUWL at dental offices and dental faculty of Babol.Materials and Methods: In this laboratory study, DUWL of dental offices from different areas as well as that of the dental faculty of Babol was microbiologically evaluated. An amount of five ml water from the syringes and high speed hand pieces before and 2 minutes after flushing and drinking water of units and tap water were gathered in three different sterile polyethylene dishes. Then the samples were cultured on the specific media and the number of the bacterial colonies was counted after keeping at 37°c for 48 hours. The data were analysed by SPSS software and chi-square, Fisher's exact and Paired t-tests as well as ANOVA were used.Results: 33.3% of all species samples were positive for presence of bacteria.Microorganisms isolated were as follow: Staphilococcus aureus, coliform, ecoli, pseudomonas aeroginosa, streptococcus (except β hemolytic group A), klebsiella, coagulase negative staphylococcus and proteus.The number of the colonies was more than the standard limit. Contamination of the water of handpieces was less reduced after flushing. Consummation of tap water compared to the water of handpleces was less and mean. Contamination of the samples gathered from the dental offices was higher than those gathered from the dental faculty.Conclusion: Flushing decreases the contamination of DUWL, but in surgeries and in persons with immunodeficiency, the use of other methods of DUWL control and decontamination is recommended.  

Introduction: Non-surgical retreatment is a way to correct the factors responsible for the failure of previous endodontic treatment. In recent years, rotary instrumentation systems have created a new option for both clinicians and patients.The aim of the present study was to quantify and compare the amount of debris extruded from apical foramen during endodontic retreatment using rotary and hand instrumentation techniques with and without use of chloroform.Material & Methods: In this invitro experimental study, root canals of 96 extracted single-root human teeth were instrumented by passive step back technique in three different working lengths: optimum, over and under (three subgroups: a, b, c). they were then obturated by a combination of cold lateral and warm vertical compaction methods.After removal of gutta-percha, re-instrumentation was performed in three groups as follows: group A; stainless steel K-type hand files plus chloroform, group B; rotary Ni-Ti files plus chloroform and group C; rotary Ni-Ti files without chloroform.Finally, the weight of extruded debris was blindly determined. The results were analyzed by Univariate ANOVA. Results: In all groups, the mean weight for extruded debris was not more than 0.37 gr. The weight of extruded debris was ranked as: Group B>Group C>Group A. The differences between three groups and subgroups were statistically significant (P<0.001).Conclusion: The results of this study showed that the largest amount of extruded debris during retreatment was found after using rotary files with solvent and in canals with overfilled obturation.  

Introduction: Vital bleaching technique is an effective method for reducing the teeth discolorations. The results of previous studies have shown that carbamide peroxide causes enamel surface roughness, so the enamel stain susceptibility increases. The purpose of this study was to compare two methods for elimination of the bleached enamel surface roughness.Materials & Methods: In this Parallel interventional study, 60 sound bovine insicors, (5x5x10 mm) were selected. After 14 days of vital bleaching with 20% opalescence gel, the specimens were randomly divided into three groups of 20; i Bond group: the enamel surface was covered by a self etch adhesive (i Bond); Fluoride group: the enamel surface was polished by a rubber cap and was treated by 2.7% Acidulated phosphate fluoride; Control group: no surface treatment was, done. In order to evaluate the lasting of each method, half of the specimens in each group were thermocycled. Data were analyzed using Kruskal-Wallis and Mann-Whitney tests (α=0.05).Results: The control group revealed a higher degree of roughness than i bond and fluoride groups before thermo cycling (P<0.05). No significant difference was observed in roughness degree between i Bond and fluoride group before thermocycling (P>0.05). The fluoride group revealed a lower roughness degree than the other groups after thermocycling (P<0.05).Conclusion: For prevention of enamel stain susceptibility after vital bleaching, polishing with rubber cap and fluoride is an effective method for elimination of the enamel surface roughness.  

Introduction: Periodontal diseases are common in leukemic patients and in most cases one of the primary diagnostic signs. The aim of this study was clinical comparison of the prevalence and type of the periodontal diseases in leukemic patients in Tabriz hospitals.Materials and Methods: In this descriptive - analytic study, 70 hospitalized leukemic patients were clinically examined in the city of Tabriz, in 2004-2005. The data were collected in a questionnaire designed for this study and were analyzed using chi-square test through SPSS software.Results: There was a significant relationship between leukemia and periodontal diseases either in general or classified into periodontitis and gingivitis (p< 0.05). Although, there was a significant relationship between different types of leukemia and age (p<0.05), sex comparison of patients with different types of leukemia, didn't show a significant relationship. In general evaluation of periodontal disease, there was a significant relationship between periodontal disease and type of leukemia in males (P=0.013), but there was not such a relationship in female patients. In general evaluation of peridontal diseases with different types of leukemia in different age groups in male and female patients, there was a significant relationship (P= 0.00) while comparing periodontal diseases with the type of leukemia in different age groups, there was a significant relationship only between absence of periodontal disease and the type of leukemia(P=0.00).Conclusion: With attention to the factors that increase the prevalence of periodontal diseases in leukemic patients, developing prophylactic and appropriate therapeutic strategies are recommended.  

Introduction: There is a significant relationship between polymerization rate and polymerization shrinkage stress in restoration. The more the polymerization rate is, the shorter viscoplastic phase of the composite would be, leaving no time for the composite to flow and consequently sudden hardening of the composite occurs. This leads into severe shrinkage stresses followed by composite detachment from cavity walls resulting in microleakage within restoration and tooth. The aim of this study was to suggest a new method of light exposure pattern for composite curing and evaluation of its effect on enamel and dentinal microleakage in respect to some other light exposure patterns.Materials & Methods: In this exprimental invitro study, flat tooth sections, 40 dentinal and 40 enamel samples were etched and Dentin Bonding Agent (DBA) (Excite@) was applied according to the manufacturer's instruction. While placed on the samples, one bulk Tetric ceram@ A3 composite was inserted in to a 2x2 mm polyethylene cylindrical mould. Samples were divided into dentinal and enamel groups of ten and light cured with Astralis 7 light exposure patterns including HIP (High Intensity Program), LOP (Low Intensity Program), PUL (Pulse Program) and SUP (Suggested Progressive Program) for 80 seconds. After curing, thermocycling, dye penetration and medial sectioning, samples were observed under a scaled reflective microscope for microleakage measurement. The data were analysed statistically using One-Way and Two-Way ANOVA and Duncan test through SPSS software.Results: There was a significant deference in microleakage between enamel samples. The microleakage rate was the highest in HIP group while no microleakage was detected in the other groups. The degree of microleakage in dentin samples was significantly less in SUP group than the others but there was no significant difference between the other groups. Conclusion: 1. The least dentinal microleakage occurred with application of suggested progressive program (SUP) compared to other testing groups.2. Like LOP and PUL light exposure patterns, no enamel microleakage occurred with SUP application. 3. Enamel microleakage was detected in HIP group which had higher light intensity.  

Introduction: Iranians have a very honorable past in traditional medicine. One of the most famous Iranian scientists in medical field is Razes (925 A.D). He has created the great medical encyclopedia of "Alhavi" (25 vols.) which contains most subjects and principles of medical science. One of these subjects is dentistry, which contains definitions, diagnosis, treatment and prognosis of the dental and oral cavity diseases and associated medical care which leads to oral health and management of the patient.In this article, a comparison was made between the scientific basis of traditional medicine and Razes view about dentistry and modern principles of dentistry.