Journal of Mashhad Dental School
Year:2008 | Volume:32 | Issue:1 (64)|Papers Count:13

Introduction: Desired mechanical properties of nickel-titanium wires have resulted in some orthodontists to recycle these wires and apply them repeatedly. The aim of this study was to evaluate load-deflection changes of nickel-titanium wires after single clinical application in three different types of crowding. Materials & Methods: 80 nickel-titanium wires (Global trade mark) with 0.014 inch diameter were randomly divided into four groups as: control, mild, moderate and severe crowding. Wires were used in patients for a period of 6±1 week then, load-deflection experiment, and using Zwick machine was done. Data were analyzed by hot telling, Fisher’s exact and Duncan tests. Results: Hot telling analysis showed a significant difference between the groups. Fisher’s exact test showed that there was a significant difference between forces at 0.5, 1.0, 1.5, 2, 2.5 mm deflection loading and unloading but there was no significant difference in 3 mm loading deflection.Conclusion: This study showed that although single application of nickel-titanium wire (at least for the wire used in this study) for one orthodontic visit causes significant decrease in force levels in different types of crowding, residual force after single clinical application is still enough for repeated clinical application.

Introduction: Total seal in the root apex for healing of periodontium is an important goal of endodontic surgery that is obtained by application of various kinds of retrograde materials. The purpose of this study was to evaluate and compare marginal adaptation of two retrograde materials (Gray MTA and Portland cement), using SEM. Material & Methods: In this invitro study, 50 extracted single-rooted human teeth with mature apices, without decay, absorption or root fracture were selected. The canals were instrumented by rotary system and filled with gutta-percha and then 3 mm of the root-end was resected. Then a cavity was prepared at the root-end with 3 mm depth and 1 mm width. Next, the teeth were divided into two groups of 25 teeth each. Each group was filled with one of the retrograde materials (Gray MTA or Portland cement). After that, the teeth were resected longitudinally to create buccal and lingual sections. Finally, the gap was determined and recorded in millimeter in two dimensions. The data were analyzed using Mann-Whitney test and Fisher’s exact test. Results: The mean gap in Gray MTA and Portland cement were 211.6 m and 326.3 m, respectively. The difference was not statistically significant. Conclusion: There was no significant difference in marginal adaptation between Gray MTA and Portland cement.

Introduction: Nowadays, posterior cross bites are a relatively common malocclusion in societies. Basically, the first step in treatment abnormalities is recognition of it completely. The treatment of cross bites is not an exception from this rule. We must be aware of all of the skeletal and dental morphology of cross bite for treatment of it. The aim of this study was to compare the palatal width and depth between the patients with bilateral posterior cross bite and patients without posterior cross bite. Materials & Methods: In this case-control study, we considered the dental casts of 30 persons (22 girls and 8 boys) with ages ranging from 7 to 14 years with bilateral posterior cross bite as the case group and dental casts of 30 persons (22 girls and 8 boys) with ages ranging from 7 to 14 years without posterior cross bite as the control group. Dental parameters of palatal depth, maxillary intermolar width, maxillary interpremolar (or the first decidous molar) width and mandibular intermolar width were measured. These measurements were done by korkhaus instrument and student-t-test was used for analysis of data. Results: None of the parameters were significantly different between girls and boys in both groups, except for mandibular intermolar width which was greater in boys in control (P=0.016) and case (P=0.01) groups. In both boys and girls with posterior cross bite, maxillary intermolar and interpremolar width was smaller, palatal depth was higher and mandibular intermolar width was larger compared with those without posterior cross bite (P<0.05). Therefore in all cases with posterior cross bite compared with those without posterior cross bite, palatal depth was higher, mandibular intermolar width was larger, and maxillary intermolar and interpremolar width was smaller (P<0.001).Conclusion: It can be concluded that in patients with bilateral posterior cross bite compared with patients without this type of malocclusion, palatal depth was higher and maxillary width was smaller.

Introduction: The purpose of this study was to compare marginal leakage of class II amalgam restorations lined with a resin- based desensitizing agent and a self-etching adhesive system with copal varnish. Materials & Methods: Fifty six freshly extracted human premolar teeth were divided into four groups. Class II box only cavity preparation was prepared on mesial and distal surfaces of each tooth While the cavities in two groups were lined with desensitizing agent; Viva Sens (A) and adhesive system; Clear Fil S3 Bond (B),one group was treated with copal varnish; Copalite (C), and last group was used as control, without any lining (D). Spherical high copper amalgam (Oralloy) was hand-condensed into each preparation, specimens were thermocycled, stained and sectioned. Microleakage was graded using a stereomicroscope. Microleakage scores were calculated and analyzed. Kruskal-Wallis and Mann-Witheny tests were used for analysis of data (a=0.05). Results: For the leakage values of groups A and B, T-test revealed less microleakage with Viva Sens (P<0.05). Kruskal-wallis test showed significant difference in four groups (P<0.05). Clear Fil S3 Bond showed less microleakage than control group, but leakage in copal varnish and Clear Fil S3 Bond was similar. Less microleakage was revealed with Viva Sens when compared with the other groups (P<0.05).Conclusion: Viva Sens reduced microleakage of Class II high copper amalgam restorations significantly more than the Clear Fil S3 Bond and copal varnish.

Introduction: Mucoepidermoid carcinoma is the most common malignancy in salivary glands. This tumor has a variable biologic potential, so it was first divided into two groups: one with malignant behavior and the other with benign behavior and good prognosis. The purpose of this study was evaluation of TP53 oncoprotein and its relation to different grades of mucoepidermoid carcinoma. Materials & Methods: This retrospective study included 22 paraffin embedded mucoepidermoid carcinoma samples stained by H&E. The samples were classified into low grade, intermediate grade and high grade. Then, new sections were made and stained by immunohistochemistry method (IHC method) for TP53 marker. Finally, the relation between the two methods was statistically (ANOVA and Kendall test) analyzed. Seven sections of normal salivary gland tissue were also used as control group. Results: All control cases were negative for TP53 marker while 68.2% of mucoepidermoid carcinoma samples were positive. A significant relation was revealed between histological grade and nuclear TP53 staining by IHC method.Conclusion: Parallel to increasing histologic grade of salivary gland mucoepidermoid carcinoma, TP53 expression is also increased so that immunohistochemistry technique is helpful for determination of the biologic behavior of salivary gland mucoepidermoid corcinoma and prognosis of patients.

Introduction: Health is the base for Development and also health level is affected by the development. Through Culture Promotion attracting Public cooperation, we can change their Knowledge, attitude and behavior about oral and dental health. This study aimed at determining the level of knowledge, attitude and behavior among staff of health and treatment centers No 1, 2 and 3 of Mashhad city about oral and dental health. Materials & Methods: This research was a descriptive cross-sectional study. This Study was conducted on 186 staff of health centers in the city of Mashhad who had been selected through multistage sampling. After completing of the questionnaires by the staff, the data were collected and then analyzed by Kruskal Wallis statistical test. Results: This study showed that among the 186 cases studied, 23.1% had good knowledge and 19.9% had poor knowledge about oral and dental health, while only 2.2% had good attitude and 9.2% of the cases had good behavior. This study showed that the level of knowledge about oral and dental health had a statistically significant relationship with educational level (P=0.004), So that the dentists had the highest level of knowledge and the technicians had the lowest level. This study revealed that among these three health centers in Mashhad, health center No 2 staff had the lowest knowledge level.Conclusion: According to the low knowledge, attitude and behavior of the staff of the health centers No 1, 2 and 3, establishment of strategies for continuous education courses seems necessary.

Introduction: The use of general anesthesia for extensive dental procedures in children is sometimes necessary to provide safe, efficient, and effective care. Hospital dentistry and using general anesthesia is limited in our country. The aim of this study was evaluating the extensive pediatric dental procedures which have been done under general anesthesia during a two-year period. Materials & Methods: This descriptive cross-sectional study was done on 72 pediatric patients who had been transferred into the operating room for dental procedures. General anesthesia was induced with sevoflurane in presence of parents. Then anesthesia was maintained with propofol or remifentanyl and nitrous oxide. Vital signs and any predefined intra and postoperative side effects were recorded. Statistical analysis was performed in SPSS software using mean values and standard deviation. Results: The mean age of the patients was 7.2±4.10 years and mean anesthesia time was 2.1±1.48 hours. Thirty one patients (43.1%) had no coexisting disease. 26.4% had cerebral palsy and 15.2% had mental retardation. 15.3% of patients had unknown syndromes. Dental procedures included 215 palpotomies, 57 palpectomies, 293 amalgam fillings, 123 glass-ionomer restorations, 15 scalings, 138 extractions and 101 crown cases. Tachycardia was reported in 9 patients, bradycardia in 7, and hypertension in 6 and hypotension in 1 case during anesthesia. Hemorrhage and swelling were the most common complications during interventions that were seen in 7% and 2.1% respectively. 592 teeth were treated finally. Vomitting, pain and agitation were more common complications after recovery that was reported in 28, 17 and 7 cases respectively. Illusion and restlessness occurred in one patient due to central anticholinorgic syndrome which resolves spontaneously 96 hours after the surgery.Conclusion: Although it is impossible to have a control group under local anesthesia due to long operation time, in our study, extensive dental procedures under general anesthesia were an acceptable method with few preventable complications in especial cases such as poor cooperation even in presence of coexisting diseases. Certainly, quality of care will be increased with providing hospital dentistry programs. More studies with more cases are needed.

Introduction: The effect of removal of smear layer has already been a subject in many investigations, and has been a matter of controversy. Of course there is no doubt that sealer penetration would be facilitated when smear layer removed. The aim of this study was evaluation of the relationship between sealer penetration and apical microleakage after usage of MTAD. Materials & Methods: In this invitro study, 135 human single root extracted teeth were selected. The teeth were divided into three groups (40 samples in each) as experimental groups as follow: Group 1: Serum was used for irrigation (with the smear layer). Group 2: EDTA 17% was used for irrigation (removal of the smear layer). Group 3: MTAD was used for irrigation (removal of the smear layer) and 15 teeth were considered as the control. The teeth in each group were divided into two subgroups (20 teeth) to be filled either with AH Plus or Dorifill sealer. Sixty teeth were selected for dye penetration with methylene blue and statistically analysed using One-Way and Two-Way ANOVA. In the other 60 teeth, sealer penetration was evaluated using SEM. The data were statistically analysed using Kruskal-Wallis and Mann- Whitney tests. The end relationship between dye penetration and sealer penetration was evaluated by spearman correlation test. Results: There was no significant difference between the three types of irrigants. There was a significant difference between the two sealers. AH plus revealed less dye penetration. Minimum dye penetration was observed in MTAD group with AH Plus and maximum dye penetration was observed in Serum group with Dorifill. Sealer penetration in MTAD and EDTA groups were better than Serum group. AH Plus was better than Dorifill. The correlation between sealer penetration in dentinal tubules and dye penetration wasn't statistically significant.Conclusion: Type of irrigant didn't affect apical microleakage but type of sealer affected microleakage. AH Plus proved to be better. AH Plus showed greater sealer penetration. Greater sealer penetration does not necessarily reduce apical microleakage.

Introduction: Since different factors are effective in high spreading of TMD this study was conducted to determine the prevalence of TMD and related factors in patients referring to dental school of Azad University of Tehran in 2005. Materials & Methods: This descriptive-analytical study was conducted on 261 patients reffered to the faculty of Dentistry of azad university of Tehran in 2005. All samples were evaluated through three frameworks. The data were statistically analysed by chi-square test. Results: The average age of the samples was 34±12.4. Eighty nine samples were suffering from TMD. The prevalence of TMD was 34/1%. All related factors under the study (age-sex-parafunction habits-trauma-orthodontics-anxiety and depression) showed significant correlation with TMD (P<0.05), while among TMD and occlusion (Angle classification), no significant correlation was observed.Conclusion: The frequency of TMD was almost high. Among All related factors except for the occlusion, there was a significant relationship. Considering the recognized complications of this disease, it is recommended to study the etiology.

Introduction: The shape of a patient face is commonly used as a reference to select the shape of the maxillary central incisors in edentulous patients. The validity of this relationship has not been proved. The objective of this clinical study was to determine whether a relationship exists between maxillary central incisor and face shape. Materials & Methods: In this descriptive analytical study two standard digital photographs of 186 students were made, one full face and the other from two maxillary central incisor’s computer software named PhotoShop (7.0) was used for assessing correlation between tooth and face formed by superimposition. A visual analysis was made to determine the extent of correlation. In addition, the overall shape of the face and teeth was classified in ovoid, square, tapered, squaretapered and tapered- square groups and compared to gather. Statistical analysis was performed using chi-square and Fisher’s Exact tests. Results: The comparison of the face shapes with the reverse out line forms of left and right maxillary central incisors showed that 24% of cases had unsimilar faces and tooth forms, 51% had similar face and tooth firms and only 25% had correspond state. Women produced a better match than men 44% of subjects had the same tooth and face forms but for 56% of subjects, they were different.Conclusion: In this study correspondence between face and tooth forms occurred in one forth of cases. As a conclusion, no significant relationship existed between the face shapes and the inverted tooth forms.

Introducion: Various evidences show a higher prevalence of temporomandibular disorder (TMD) in women. The purpose of this study was to evaluate T.M.D etiologic factors in women referring to Mashhad Dental School. Materials & Methods: Twenty-five patients with jaw clicking and 19 with M.P.D syndrome were randomly selected among female patients referring to Mashhad dental school. Seventeen women with no signs and symptoms of temporomandibular disorder were used as the control group. The women were between the ages of 18 to 40. All of them were examined for TMD and etiologic factors such as Parafunctional habits (Bruxism & Clenching) and premature contacts in eccentric movements. The level of blood estradiol and progesterone status was also recorded. The data were analyzed by Kruskal Wallis and Chi-square tests through SPSS software. Results: Although there was a difference in level of blood estradiol and progesterone between TMD patients and control group, this difference was not significant. There was a significant difference between the two groups regarding parafunctional habits (P<0.001). There was no significant difference between the two groups regarding eccentric premature contacts (P=0.098) Conclusion: In this study, the most important TMD etiologic factor was parafunctional habits (Bruxism and clenching) and the second effective factor was eccentric premature contacts. There was no relation between the level of boold estradiol and progesterone and the incidence of TMD in women.

Introduction: Since the health of children living in orphanages is related to the health policies implemented in those centers, evaluation of their health status, at least annually, can reveal the shortcomings and help to correct them. The purpose of this study was to determine dental treatment needs in 6-12-year old children in Mashhad orphanages. Materials & Method: This cross-sectional descriptive study was carried out on all 6-12-year old children (137 children) in Mashhad orphanages. Prevalence and severity of dental caries (using DMFT/dmft index), dental treatment need (using UTN index), gingival health status (using MGI index), and oral health status (using PI index) were evaluated. The data were analyzed using chi-square, and Mann-Whitney tests. Results: 42% of children were male and 58% were female. 73.7% and 43.8% of children had some types of treatment needs in their primary & permanent teeth respectively. The mean DMFT was 1.37±1.61 (1.38±1.64 in girls & 1.36±1.57 in boys). The mean dmft was 3.4±2.7(3.2±2.47 in girls & 3.61±3.0 in boys). 57.2% had poor oral health status (PI index). 67% had moderate and severe gingivitis (MGI index). Conclusion: Caries experience, especially in primary dentition was high in terms of prevalence and severity and most of the children had some types of treatment need. Effective oral health promotion strategies need to be implemented to improve the oral health of children living in orphanages.

Introduction: Leishmaniasis is a common cutaneous disease which is due to the infection with protozoan parasite named leishmania. This parasite is transmitted to a human by an infected sand fly. Both clinical forms of cutaneous leishmaniasis (dry-wet) are endemic in Khorasan province. The purpose of this study was to report two leishmaniasis cases with just lip involvement. Results: This report is about two patients with lip leishmaniasis, without any skin or mucusal involvement in which the clinical features were diffuse lip swelling and ulcer in lower lip vermelion. These patients had been referred to oral medicine department of Mashhad dental school where a smear and biopsy were obtained which confirmed the clinical diagnosis of leishmaniasis. Thereafter, the patients were referred to a dermatologist for treatment. In later follow up, complete healing of lesions was observed. Conclusion: The city of Mashhad is one of the centers with high frequency of dry cutaneous leishmaniasis and facial involvement in this disease is common. So it is necessary for dentists to consider leishmaniasis in differential diagnosis of lip and nose swellings and ulcers.