Journal of Dental School
Year:2007 | Volume:24 | Issue:4 (70)|Papers Count:23

Background and Aim: Dentin hypersensitivity is a frequently problem after periodontal therapy. Many substances have been advocated for the treatment of this problem and numerous clinical studies investigated their efficacy. The aim of this clinical trial was to study the effectiveness of potassium nitrate and sodium fluoride gels for the reduction of tooth sensitivity following initial phase of periodontal therapy.Methods & Materials: In sixteen subjects following initial phase of periodontal therapy 274 sensitive teeth were detected. Randomly in one quadrant Isodan and in other quadrant sodium fluoride was applied and in the other applied no material. After one and two weeks plaque index and pain score were assessed in each group. The data obtained were analyzed by means of chi - square and Mann - whitney test.Result: There were significant difference between the two groups (Isodan and NaF) and control group at the first week and immediately after scaling in reducing dentin hypersensitivity whereas no significant difference was found between Isodan & NaF in the whole. At the second week and immediately after scaling, there was a significant difference between Isodan and the control group (P<0.05), but there was no significant difference between NaF and the control group. Reduction of plaque index was significant in all groups between the first and the second week but there was no significant difference between groups.Conclusion: This study showed that both gels appear to have therapeutic effects to reduce hypersensitivity, however Isodan has more prolonged effect. Also proper plaque control reduced tooth hypersensitivity.

Background & Aim: Each group or nation should have its own cephalometric norms to be used in diagnosing and treatment planning of their malocclusions. There was no cephalometric norm available for Mashhad children and we had to use other nations' norms available in textbooks. The aim of this study was to determine the cephalometric norms of Mashhad children with normal occlusion to be used in diagnosis and treatment planning of orthodontic problems.Methods &Materials: This study was a cross-sectional and descriptive one done on 30 girls and 30 boys with normal occlusion. The mean age was 12 years, 4 months and 13 years, 4 months respectively by gender. The samples were selected randomly from 1940 guidance schools children of 4 different areas of Mashhad. These children and their parents were born there. Medical and dental histories, study casts and lateral cephalograms in natural head position were taken. Cephalograms were traced; SPSS software and Dahlberg formula were used, student T-test was done and results were extracted.Result: The results of this investigation showed that in Mashhad children axial inclination of the lower anterior teeth is more prominent and the lower one-third of their facial height is more than northern European Caucasians. These variables are more in boys than in girls (P<0.05).Conclusion: Regarding to the findings of this investigation which showed differences in dentofacial characteristics of Mashhad children in comparison northern European Caucasians, attention should be paid in diagnosis and treatment planning.

Background & Aim: Medications, systemic diseases, head and neck radiotherapy and mental stress reduce the salivary flow rate and dispose one to dental caries and oral disease. There are different ways to compensate reduction of salivary flow rate such as sour candies, lemon, special stimulating sprays or lacques and chewing gums. Many factories such as Wrigly factory producing chewing gums claim to reduce caries rate by increasing salivary flow pH and after chewing their product. The purpose of this research was to compare the effect of sugarfree Orbit chewing gum and natural turpentine on the salivary flow rate and pH.Methods &Materials: This single blind randomized clinical trial was accomplished on 16 dental students of Shaheed Beheshti University in 1383 using a cross - over method. The samples were selected by simple non – randomized method divided into two groups, A and B each including eight persons. The saliva of all samples was collected 5 minutes after eating 2 sweet biscuits by active method during 10 minutes. Then the volume of collected saliva was measured and immediately the pH was determined by a calibrated pH meter. After 72h wash out period, on the 3rd day two biscuits were given to all of the samples and after 5 minutes 14 grams of sugarfree Orbit gum was given to samples of group B, the amount of saliva collected during 10 minutes measured, and the pH was registered. Again, after 72 h washed out period, on the 3rd day, two biscuits were given to all of the samples and after 5 minutes 14 grams of sugarfree Orbit was given to members of group B and equal amount of Turpentine to members of group A during 10 minutes of chewing. The amount of saliva and its pH was measured and registered again. The data were analyzed with sphericity and Friedman tests.Results: The mean saliva flow rate after having the biscuits, chewing the gum and Turpentine was 5.0±0.8 ml, 15.8±1.0 ml, 13.7±1.3ml, respectively. The difference among three groups was statistically significant (P<0.005). The mean salivary pH at the beginning was 5.8±0.6 and after using gum and turpentine turned to 7.4±0.5 and 7.1±0.3. All of these amounts had a statistically significant difference (P<0.001).Conclusion: Sugarfree Orbit chewing gum causes increase of saliva flow rate and its pH. Therefore, preventing the mouth diseases caused by Xerostomia and teeth diseases.

Background and Aim: Patients are faced with some complications after third molar extraction. Considering this fact, some techniques are developed to reduce these complications, such as, Chlorhexidine rinse and antibiotic usage. Considering the importance of these complications, this study was conducted for the evaluation of chlorhexidine rinse and antibiotic usage to reduce post extraction complications of mandibular third molar in Tehran University Dental School.Methods & Materials: The study was a randomized double - blind experimental one. The study cases were assigned to three groups, using Penicillin V (2 gr.), Chlorhexidine rinse using and control group. The opening range of jaw and special distances in the face were measured before surgery, 48 hours and one week later. The statistical tests used were Kruskal- wallis and Mann - whitney U.Results: Penicillin V and Chlorhexidine rinse had no effect on infection, trismus, swelling and dysfunction 7 days after extraction. Chlorhexidine rinse reduced swelling at 48 hours after extraction only, meanwhile the effect of Chlorhexidine rinse and Penicillin V on swelling after 48 hours differed significantly (P<0.01).Conclusion: The study confirmed the positive effect of Chlorhexidine rinse on removing swelling at 48 hours after extraction of mandibular third molar, but it had not any effect on other complications. The group using Penicillin V did not show any decrease in post surgical complications.

Background and Aim: Recurrent aphthous stomatitis (RAS) is one of the most common and the most pathologic status of oral soft mucosa. Frequencies of RAS are between %10 and %20 in population. Numerous agents have been evaluated in the treatment of RAS with mixed results. These agents include antihistamines, anesthetics, vitamins, Levamisole, antibiotics and corticosteroids. The aim of this study was to compare the efficacy of Irsha and Persica mouthrinses on RAS.Methods & Materials: Thirty - nine patients with recurrent aphthous stomatitis were selected for this double blind clinical trial (21 females and 18 males). Twenty patients were assigned to use Irsha (group A) and nineteen to use Persica (group B) mouth rinse, twice a day for 30 seconds. This base population was identified by clinical examination of aphthous ulceration and based on specific criteria for clinical diagnosis, including appearance, location, size and number of lesions. The results were analyzed by Wilcoxon and Mann - whitney U tests.Results: In three months treatment, the mean value was respectively 18.5 for Irsha and 21.25 for Persica. There was no significant difference between them. Both Irsha and Persica significantly reduced the duration and severity of RAS as compared with baseline in a protocol that included clinical diagnosis, individual patient baseline evaluation and pervision of each patient during the study.Conclusion: According to this study Persica and Irsha mouth rinses have similar effects on RAS. Both of them reduce pain, sore and duration of healing and can be used for treatment of RAS.

Background and Aim: Problems like perforation of furca may happen in root canal therapy. The material used for sealing of perforation is important in control of inflammation and periodontal repair. Previous studies show that ProRoot is the best material for treating these cases but is too expensive. Recently one Iranian material which is called cold -ceramic is produced in Yazd University. The aim of this study is to compare the histologic effects of cold ceramic and pro-root in healing of periodontal tissues after sealing of furcation perforation in dog teeth. Methods & Materials: Thirty five premolars of one year old dogs were used. After anesthesia by injection of lidocaine, access cavity was prepared and root canal was filled by gutta percha and AH26 sealers with step-back technique. Then the furca was perforated 3x3 mm with long burs and washed by physiologic serum. The perforated zones were sealed randomly by pro-root and cold ceramic and the cavity was filled with amalgam. Six teeth were considered as positive and negative controls. Two dogs after one month and two after two months were sacrificed by vital perfusion. Jaws and teeth were separated and put in formalin 10%. After laboratory procedures, the samples were investigated by microscope. The data was analyzed by Mann- whitney and Kruskal- wallis tests.Results: The results showed that ProRoot caused more repair in the same condition but there was no significant difference between the two materials after one and two months. Conclusion: Considering the lower price and availability of cold ceramic, if other testes are confirmed, cold ceramic may be a suitable substitution for ProRoot.

Background and Aim: Recently some evidence has been presented that periodontal disease is associated with an increased risk of cardiovascular disease. The hypothesis of this study is that periodontitis may be associated with elevated blood lipid levels, a known risk factor for atherosclerotic disease. Methods & Materials: The levels of plasma lipids was measured in 40 subjects with chronic periodontitis (CP) and compared with those obtained in 40 controls. Periodontal variables included: Plaque Index (PU), Probing Pocket Depth (PPD), Clinical Attachment Level (CAL) and Bleeding On Probing (BOP). Laboratory tests included: total cholestrol, triglyceride, LDL and HDL. Statistical tests used were Kolmogorov-Smimov, Kruskal Wallis, Spearman's rank correlation, Exact fisher and Independent Samples Student t-test. The level of statistical significance was established at P£0.05.Results: There were no statistically significant differences between blood lipid levels in the two groups but in the control group, there were positive correlations between BOP and cholestrol (P=0.01). In the CP group there were positive correlations between PPD and cholestrol (P=0.037), PPD and LDL (P=0.034) and PPD and the number of missing teeth (P=0.019).There were also positive correlations between BOP and cholestrol (P=0.005) and BOP and LDL (P=0.006) in the CP group.Conclusion: The results of the present study suggest that in patients with periodontitis, as the periodontal parameters (BOP and PPD) increase, the blood levels of cholestrol and LDL increase too, but it is not clear yet whether the observed changes in lipid metabolism are the cause or the consequence of periodontitis.

Background and Aim: To date, several materials have been used for root end filling in endodontic surgery. Optimal properties of MTA in invitro and invivo studies have been proven. On the other hand, based on some of the studies, Root MTA (Iranian MTA) and Portland cement are similar to MTA in physical and biologic properties. The aim of this investigation was to assess the marginal adaptation of Gray Pro root MTA, White Pro root MTA, Root MTA and Portland cement Type I root-end fillings under scanning electron microscope.Methods & Materials: Eighty extracted single-rooted teeth were selected. After canal preparation and root-end resection, root-end cavities were prepared ultrasonically. They were divided at random into four test groups of 20 each. The cavities were filled with Gray & White Pro root MTA, Root MTA and Portland cement. The root-end surface topographies were reproduced by means of polyvinylsiloxane impressions and epoxy resin replicas. Then scanning electron micrography (SEM) images of each replica were taken. The material-tooth interface on each photograph was divided into 16 equidistant areas and maximum gap size was recorded in each area. The means of 16 numbers of each photographs was calculated. The means of calculated numbers related to each group were counted. Statistical analysis was performed using ANOVA test.Results: Gap sizes at calculated points were smallest in Portland cement root-end fillings and largest in White Pro root MTA group. Calculated gap sizes for White Pro root MTA, Root MTA and Gray Pro root MTA and Portland cement group were subsequently 16.3975, 15.4185, 12.8880 and 11.3150 mm. Portland cement produced a significantly superior marginal adaptation to Root MTA and White Pro root MTA, and the gap size in Gray Pro root MTA group was significantly smaller than White Pro root MTA (P<0.0001).Conclusion: under this study, the marginal adaptation of both Portland cement and Root MTA was good. After performing more invitro and invivo studies we hope to use Portland cement, which is very economic.

Background and Aim: A major-part of dental work is associated with fixed prosthodontics. The permanence of cemented restorations is based on different factors for instance, retention, appropriate cement and applying the correct way of use. The aim of this study was to compare the retention of zinc phosphate and polycarboxylate cements with the common core build up materials such as amalgam, composite, casting alloy and coremax II.Methods &Materials: In this experimental study twenty 6x6 mm cylinders were produced from every core build-up material. The teeth were prepared by means of mounting and cutting by high speed handpiece. To build - up a substitutionary crown cylinder, 100 cylinders were made by means of based metal casting alloy ingut with external diameter of 12 mm, height of 6 mm and a 6.1 mm hole in the center. 10 samples were cemented with zinc phosphate and the other 10 with polycarboxylate. The samples were placed under the dartec machine and the necessary power for egress of piston from cylinder was measured by the dartec. The data were analyzed by SPSS software, factorial ANOVA and Duncan tests.Results: The retention mean value of zincphosphate cement to casting alloy, Amalgam, Composite, Coremax II and the tooth sample was respectively as follows: 77±5, 71±5, 37±4, 32±2 & 24±2 MPa. The retention mean value of polycarboxylate cement to tooth, Amalgam, casting alloy, Composite and Coremax II was respectively as follows: 37±3, 32±6, 22±4 10±1, & 8±1 MPa. ANOVA test demonstrated statistically significant differences between retention mean value of zinc phosphate and polycarboxylate cement with 5 core build-up materials (P<0.001).Conclusion: The reason of more retention in polycarbocylate cement to tooth structure can be related to chemical bonding between tooth and cement. The results of this study revealed that the casting alloy provided more retention than amalgam. The more retention of amalgam in comparison with composite and coremax II can be related to a more powerful compressive strength of amalgam.

Background and Aim: Dental clinics may encounter patients who are involved with head and neck cancer and are under chemotherapy. This review discuss about oral and periodontal complications due to chemotherapy and current ways to decrease this complications. 20 articles about chemotherapy and related complications were used for this review.Periodontist has to participate before and during the treatment of patients with head and neck cancers who receive chemotherapic agents and his / her cooperation with oncologist is necessary to achieve the best results. Participation of periodontist in all treatment stages of patients with head and neck cancers is critical.Conclusion: Participation of periodontist is necessary before beginning of treatment of patients with head and neck cancers and this cooperation must continue during and after treatment to achieve the best results.

Background & Aim: One of the important factors in orthodontic treatment planning is prediction of growth potential which is applied by stages of skeletal age and or another criteria such as the chronological age, sexual maturity, dental development stages, and height and weight. Another importance in determining the patient's age is in legal medicine to determine the guiltiness' age, more or less than 18 years. The aim of this study is to assess the correlation between skeletal, dental and chronological age.Methods & Materials: This diagnostic study was performed as a cross sectional method in dental faculty of Yazd Shaheed Sadoughi University from 2004 to 2005. 58 Patients of 15-25 years old who referred to private dental office were selected. The samples were chosen with continues method until it reached to the desired total numbers. Each patient completed 4 questionnaires consisting of chronological age, determined age from panoramic radiography, measured age from surgical teeth and determined age according to hand wrist radiography. Panoramic radiographs were read by two oral and maxillofacial radiologists and hand wrist radiographs were read by two radiologists. Statistical analysis was performed by Paired T, Correlation coefficient, Wilcoxon, Smimov - Kolmogorov.Results: The least fault obtained from determined age and real patient age was related to the right mandibular surgical wisdom teeth (1.6 months difference). Hand wrist radiographs had the most fault in age determination and both of the two radiologists determined the ages less than real ages (P=0.000). In the statistical analysis, it seemed that the age determination from wisdom teeth by panoramic radiographs is just a suitable method. When age determination is considered to special case, the maxillary right wisdom teeth showed more proximity to real age (39.4%) and mandibular left third molars (24.5%) and mandibular right third molars (23.9%) were in the next steps.Conclusion: Age prediction by wisdom teeth on panoramic views is a proper way to report for legal medicine. Since the hand wrist radiographs had the most faults in age prediction, its advantage is not proposed, in individuals more than 18 years old.

Background & Aim: G.B.R is a procedure which is used for treatment of the osseous defects. In this procedure new bone forms in the defect. The aim of this study was to compare the bone formation with madrepora and membrane, madrepora alone and membrane alone.Methods &Materials: This study was done on 5 white Newzland rabbits. Three defects were created in parietal bone. The first defect was filled with madrepora particles (250-500 micron) and covered with a piece of membrane. The second defect was filled only with madrepora and the third defect was left empty and covered with membrane. After 8, 9, 11, 14, and 15 weeks animals were sacrificed. Statistical analyses were done by Kruskal - wallis and Mann - whitney U tests.Results: Histologically the defect which contained madrepora and membrane was filled with trabecules after 15 weeks. In the second defect the trabecules were seen only in the periphery. The defect was filled with connective tissue in the third defect.Conclusion: Madrepora's pieces have biocompability with rabbit tissues and the process of repair in the osseous defect was accelerated.

Background and Aim: As need assessment is the first step for oral health promotion, the level of knowledge and attitude toward oral and dental health among Zahedan's junior school students was evaluated in this research.Methods & Materials: In this cross - sectional descriptive research, 800 students among junior school (431 boys & 369 girls) were chosen through cluster sampling method. Data was gathered through a self report questionnaire including gender, level of education, school type, parent occupation and level of their education, knowledge and attitude among students. The data were analyzed by SPSS (ver. 10) and chi - square statistics.Results: Sixty percent of students had moderate level of knowledge and 29.6% had desired knowledge. 17.3% held positive attitude and 45% held a moderate attitude toward oral & dental health. Significant relationship was found between oral health knowledge and attitudes of parents with their educational level and occupation (P<0.001). There was also a significant relationship between student's educational level, school type, and gender with oral health knowledge (P<0.001). The girls and students of private schools and last year of junior high school had a better level of knowledge. 56.5% of students brushed at least twice daily and 18.8% used dental floss. 43% of students had not dental visit for the past 12 months. The most important source of oral and dental health information of 75% of students were dentists and parents, and there was a direct relationship between health habits (at least brushing twice a day & using dental floss) and visiting the dentist in the last year with the level of knowledge and attitudes.Conclusion: The level of knowledge of Zahedan's junior high school students about oral health was not enough which may be due to poor teacher's role in education of oral and dental health.

Background and Aim: The aim of this study was to evaluate the effect of glass-fiber on the flexural strength of composite resins.Methods & Materials: The study was done experimentally in which flexural strength of glass - fiber reinforced composite resins were assessed with a three-point load test on 22 samples. 11 samples of composite resin blocks and 11 samples of composite resins reinforced with glass- fiber were prepared in a mold of 25x6x2mm and stored in 100% of moisture for one month, until they were ready for testing in an Instron Universal Testing Machine using a crosshead speed of 1 mm/min. Student t test was used for statistical analysis.Result: Flexural strength in the first group was 22.39±3.38 MPa and in second group was 29.74±2.36 MPa. According to t test analysis, the difference between the two groups was statistically significant. (P<0.01).Conclusion: The results of this study suggest that the flexural strength of the fiber-reinforced composite made from glass - fibers was more than composite resin.

Background and Aim: Dentin hypersensitivity is a transient toothache with multiple external stimuli that has high prevalence in adults (about one out of every seven patients). The aim of this study is clinical comparison of the role of potassium nitrate and strontium chloride in decreasing hypersensitivity following periodontal resective surgery. Methods & Materials: Fifty one patients with tooth hypersensitivity following resective periodontal surgery participated in this study. Patients were randomly divided into 3 groups. group I: patients using Sensodyne toothpaste containing potassium nitrate, II: patients using Sensodyne toothpaste containing strontium chloride and group III: as control. The patients used the dentifiices for 14 days. The severity of hypersensitivity was recorded in specific questionnaires designed for this study and verified by visual Analogue Scale (VAS). Furthermore, the severity of hypersensitivity of different teeth and the different irritants producing hypersensitivity according to gender and age were recorded. Collected data was statistically analyzed using exact Fisher and Chi-square tests. Results: Out of 51 participants in the study there were 30 females and 21 males. No statistically significant differences were found between group I and group II (P>0.05), but there were significant differences in hypersensitivity reduction between group III with group I & II (P<0.05). Cold was the most common irritant in this study 96.2% and after that, heat with 33.3% of cases. The most common involved teeth were mandibular lateral and central incisors respectively.Conclusion: According to the high rate of tooth hypersensitivity following resective periodontal surgery, the use of desensitizing agents such as potassium nitrate and strontium chloride along with good oral hygiene are recommended.

Background and Aim: No clinical trial has been done in relation to successful coverage of gingival recessions with and without odontoplasty. This study was designed to evaluate the effects of odontoplasty with subepithelial connective tissue graft (SeCTG) on the outcome of root coverage on abraded teeth with gingival recessions, attachment level, height of keratinized gingival and teeth sensitivity.Methods & Materials: Thirty-six class I, and III Miller recessions were treated in 10 patients, using SeCTG with coronally positioned flap with (test group) and without (control group) odontoplasty. Clinical measurements probing depth, abrasion depth, height of recession (HR), width of recession (WR), height of keratinized gingival (KG), clinical attachment level (CAL), width of interdental papilla, bone level and vestibule depth were recorded at base line and 3 months after surgery. The changes in variables were evaluated by paired t test and Wilcoxon's sign ranked test.Results: Probing depth before and after surgery was reduced 0.44 mm in the test group which was not statistically significant. However the difference was significant in the control group (P=0.007). Differences between mean clinical attachment level (CAL), height of recession (HR), width of recession (WR) and height of keratinized gingival (KG) in test and control groups before and after surgery were statistically significant (P<0.0001). Differences between the two groups in CAL, and HR were statistically significant (P=0.026, P=0.03). Difference between mean two groups in KG before surgery was statistically significant (P=0.036). However difference between two groups was not statistically significant. Difference between before and after surgery in vestibule depth was not statistically significant. Interdental papilla in test group had not any relation with mean root coverage, however in control group the relation was highly significant (P=0.001,r=0.75). Bone level in mid facial in both groups had not significant relation with mean root coverage. Abrasion depth in test group had not significant relation with mean root coverage. However, in control group, had significant relation with mean root coverage (p=0.003, r =0.65).Conclusion: SeCTG with coronally positioned flap is a predictable method for root coverage with shallow, moderate and deep recessions. Odontoplasty in abraded teeth in order to decrease avascular surfaces, irregularities and root convexity results in better clinical outcome to gain clinical attachment, root coverage and keratinized gingiva.