Statement of Problem: Postoperative pain after periodontal surgical procedures is a common complaint. Celecoxib, a cyclooxygenase (COX)-2 inhibitor NSAID, is associated with a lower incidence of well known side effects reported for the conventional NSAIDs. Sparse information is available on the efficacy of Celecoxib, or Prednisolone, a steroidal anti-inflammatory drug, following periodontal surgery. The aim of the present study was to compare the analgesic efficacy of Celecoxib and Prednisolone after periodontal mucoperiosteal flap with minor osseous surgery. Methods and Material: In this randomized, double-blind, cross-over, placebo-controlled, clinical trial, 20 patients with generalized, moderate to severe chronic periodontitis underwent three mucoperiosteal flap with minor osseous surgery with at least 4 week interval. Each quadrant was randomly assigned to receive one of the following medications in two doses starting one hour before surgery: 200 mg celecoxib, 10 mg Prednisolone, and placebo. The patients filled out a visual analogue scale (VAS) and a five-point verbal rating scale (VRS-5) at 11 predetermined time periods. Data analyses were performed, using Friedman, Pearson correlation and Spearman rank correlation tests. There was a statistically significant lower pain reported in the celecoxib than placebo groups during 9 postoperative time periods using VAS (p =0.03). This value was statistically significant for all the time periods under investigation, using VRS-5 (p =0.01). The level of pain was lower in Prednisolone than in the placebo groups at the four-hour period (p =0.045), and during the day after surgery (p =0.01). A statistically significant lower pain perception was reported with the use of celecoxib at three postoperative hours (3, 5 and 6) than Prednisolone (p =0.02). There was a positive correlation between VAS and VRS-5 pain rating scales used in this study (p =0.0001, r =0.938). Within the limitations of this study, preventive and postoperative uses of Celecoxib and Prednisolone were effective in the control of pain following periodontal flap with minor osseous surgery. However, during the first 8 postoperative hours, Celecoxib showed a superior efficacy in the duration and continuity of pain relief in comparison with Prednisolone.

Statement of Problem: Cobalt-base alloys are widely used for fabrication of dental structures and dental and orthopedic surgical implants due to their biocompatibility. Application of coatings on the implants with bioactive materials improves their fixations in human body. Performing the operation during the casting process is very interesting due to the economical benefits and higher quality. The aim of this study was surface bioactivation of the dental Co-Cr-Mo alloy via performing the bioactive coating on the surface of the alloy during the investment casting process and evaluating the properties of the coating.Methods and Material: In the present experimental research, the Co-Cr-Mo alloy (ASTM F-75) specimens were poured into the molds prepared via investment mold technique. The internal surface of the molds was previously coated with hydroxyapatite powder via painting coating method. The obtained specimens were analyzed by x-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy and optical microscopy. The prepared specimens were immersed in simulated body fluid (SBF) at 37 °C for 4 weeks in order to evaluate the bioactivity of the surface of the specimens. A desired coating enriched with phosphor and calcium with a thickness of 100-160 micrometer was formed on the surface of Co-Cr-Mo alloy. Formation of bone-like apatite on the surface of coated Co-Cr-Mo alloy specimen, after 4 week immersion in SBF, was the indication of surface bioactivity of the obtained specimens. Preparation of hydroxyapatite coating during the investment casting process is an economical method to form a bioactive surface on the metallic cast implants. The surface bioactivity of the dental and orthopeadic implants can promote the osteointegration and better biological fixation.

Statement of Problem: Application of fluoride and fissure sealant has an important cariostatic effect. The impact of topical fluoride, especially APF (Acidulated Phospheted Fluoride) gel on the restorative materials has been studied. To assess the effect of repeated application of APF (1.23%) on the surface roughness of two sealant materials.Methods and Material: In this experimental study, 135 specimens of two sealant materials were prepared, using Aluminum cylindrical molds in three groups of 45 including: unfilled resin sealant (Clinpro), glass ionomer sealant (Triages) and glass ionomer sealant with covering of GC varnish. Then, these three groups were divided into three sub groups of 15 as follows:Group 1, 4, 7 (control): No treatment. Group 2, 8, 5: Single application using APF Group 3, 6, 9: Four times application using APF The APF was applied on the experimental specimen every time for 4 minutes. Then, the samples were stored in the distilled water. Finally, the surface roughness of the sealants was measured using Profilometer. The statistical analysis was performed by Kruskal-Wallis and Dunn tests. Resin sealant exhibited no surface roughness changes following fluoride gel application (single or four applications). APF produced a statistically significant increase in the surface roughness of glass ionomer with and without varnish on them. Repeated application of APF on the surface glass ionomer specimen significantly increased their surface roughness. The result of the present study revealed that APF gel application significantly increases the surface roughness of glass ionomer sealants, without any effect on the resin sealant.

Statement of Problem: Dental treatment for anxious children is a great challenge for dentists. Pharmacologic techniques may lead to dental treatments with better safety and quality. The purpose of this study was to compare the sedative effect of chloral hydrate alone with chloral hydrate-hydroxyzine regimen in dental treatment of very anxious 3-5 year-old children. This study was a blind randomized cross-over trial. Each individual had his/her own control within each protocol. Furthermore, the two protocols were compared. Twenty children, who exhibited "definitely negative behavior" according to the Frankl scale, were assigned to receive oral chloral hydrate (45 mg/kg) for one session or a combination of chloral hydrate (40 mg/kg) and hydroxyzine (1.5 mg/kg) for the other session. The children's behavior during the treatment was observed and ranked by a blind examiner, based on NCBRS method. Also, the qualitative success rate was determined by Houpt rating scale for the overall behavior. The data were analyzed, using SPSS software and MANOVA test. Children in both treatment sessions presented better scores for behavior than those in the first session (p <0.001). Based on the present findings, the following negative behaviors were significantly reduced in pharmacotherapy sessions: high hand (p =0.041), crying (p <0.001), verbal protest (p =0.027) and oral resistance (p <0.001). There was no statistically significant difference between the effect of the two pharmacologic regimens during treatment sessions (p >0.05). Oral chloral hydrate) 45 mg/kg) is recommended as a sedative agent for dental treatment of very anxious children as compared to the combination of chloral hydrate with hydroxyzine.

Statement of Problem: There are different views about the optimal time for detection and prevention of maxillary canine impaction. With respect to the large individual variation in the timing of eruption of the teeth, it seems reasonable not to consider chronological age as a valid criterion in this regard. The aim of this study was to compare dental and chronological ages in the diagnosis of potential maxillary canine impaction.Methods and Material: This analytical cross-sectional study was done on 2704 students aged 10-11 year in Mashhad. In the first group (1232 children), all of the children whose maxillary canine bulges were not palpable were suspected with impaction and referred for radiographic examination. In the second group (1472 children), the children whose canine bulges were not palpable were referred for radiographic examination if only the first premolars had erupted or were erupting. The condition of the lateral incisor teeth was inspected in children suspected with impaction. The data were analyzed by comparing the proportion of success and Fisher’s exact test. From the children examined in the first group, 9.3% and from those examined in the second group, 5.5% were suspected with impaction in the clinical examination. The application of dental age reduced the number of referrals for radiographic examination significantly (p <0.05). There was an association between palatal position of the maxillary canines and anomalous lateral incisors (p <0.05). Consideration of chronological age in early diagnosis of maxillary canine impaction may result in unnecessary radiographic examination. The number of referrals for radiographic examination will be significantly reduced when the developmental stage of dentition is considered.

Statement of Problem: Conservative procedures using dentine adhesives are one of the important aspects of pediatric dentistry. The bonding performance of current adhesive systems to primary dentine has not been thoroughly researched. The aim of this study was to evaluate shear bond strength of four adhesive systems bonded to primary molars dentine.Methods and Material: For this experimental study, 48 extracted primary human molars were collected and stored in normal saline at room temperature. For shear bonding test, the labial or lingual surfaces of the primary molars were used. The flat buccal/lingual surfaces of the teeth were divided into four groups (n=12). The tested adhesives were: Clearfil SE Bond (SE); Adhese (AS); Prime and Bond NT (NT) and Exite (EX). Four dentine adhesives were applied following the manufacture's instructions. Composite (Z100) cylinders (3×4mm) were polymerized on the treated dentine surfaces and specimens were stored in normal salin for 72 hours perior to testing. After thermocycling, the teeth were subjected to shear stress using a universal testing machine (Instron) at a crosshead speed of 1 mm/min. The results were analyzed with ANOVA and Tukey's HSD test. The shear bond strength values ranged from 4.71 to 26.68 Mpa on dentine, in decreasing order of SE, NT, EX and AS. The differences in bond strengths between the four groups were statistically significant (p =0.000l). Adhesives systems are technique sensitive and in pediatric dentistry, choice of adhesive system may be affected not only by physical properties of the materials but also by factors related to the method required for their application.

Statement of Problem: Dental age is used for dental maturation description. Knowledge about dental maturation is useful for determination of the plan, time and retention period of orthodontic treatments. The purpose of this research was to compare the dental age in subjects with vertical and horizontal growth patterns. This analytic cross-sectional study was conducted on the panoramic and lateral cephalometric radiographs of 53 patients referred for orthodontic treatment including 26 boys and 27 girls, aged 8–12 years, with a mean chronological age of 9.5 years. The patients were selected according to their lower anterior facial height as a percentage of the total facial height on the cephalometric radiographs. Then the two groups, one with long and the other with short anterior facial height, were compared based on their dental ages. Dental age was determined for each subject on the panoramic view by two observers, using Demirjian's dental maturity score. The data were analyzed by independent and paired T-test, using SPSS. The mean dental age and the mean chronological age in the subjects with long anterior facial height were 9.08±1.8 and 8.6±0.87 years, respectively (p = 0.06). The patients with short anterior facial height demonstrated the mean dental age of 10.54±1.31 years and the mean chronological age of 10.25±1.09 years (p = 0.32). There was no statistically significant difference in the dental age score between the two extreme groups. Also, there was no statistically significant difference in the dental and chronological age between girls and boys in patients with long and short faces (p = 0.71, p =0.73). The difference in the dental age between long and short facial types in subjects aged 8-12 years is not clinically relevant. Boys with short anterior facial height demonstrated a tendency toward more advanced dental age (8 months), revealing no significant different; however, it should be considered important in the clinical study.

Statement of Problem: Excess consumption of acidic foods is the most common etiologic factor in human dental erosion. This study aimed at the assessment of the effect of the mostly consumed carbonate beverage and soft beer on the microhardness of the permanent teeth enamel.Methods and Material: In this experimental study, 30 extracted human molar teeth free of crack, caries, wear and hypocalcification were randomly divided into three groups. The before exposure microhardness of all teeth were measured. Then each group was exposed to one of the fresh drinks, carbonate beverage and soft beer, for 5 minutes. The exposed surface was the same in all the samples (a 5 x 5 mm square of the distal surface). The amount of drinks per sample was the same as well (40 ml). At the end of the exposure period, the microhardness of the teeth were measured again. Microhardness changes in each group were analyzed by paired t-test and those between groups were analyzed by one way ANOVA. The mean of the primary enamel microhardness after immersion in carbonate beverage (Zamzam cola) and soft beer (Behnoosh lemon delester) decreased as much as 13.76% and 5.7% respectively. Tap water did not have any significant effect on the enamel microhardness. Moreover, there was a statistically significant difference between the amounts of reduction of the enamel microhardness for each beverage. Reduction of enamel microhardness after application of Zamzam cola® and Behnoosh lemon delester® was statistically significant but after immersion in tap water there were not significant differences. However, the amount of reduction for delester group was much less than Zamzam cola®.

Statement of Problem: A correct diagnosis is the first step of treatment. The correspondence of clinical and histopathologic diagnosis is an indicator of the correct opinion of the surgeons and pathologists in diagnosis. This study aimed to evaluate the agreement rate of clinical diagnosis and histopathologic reports of the patients referring to oral pathology department of Shiraz dental school from 2001-2006.Methods and Material: In an analytic, retrospective study on 613 files of patients from the archive of oral pathology department, data on the age, site and surgeon were collected and analyzed by SPSS software using Chi-square test. Eighty one percent of the clinical diagnoses were confirmed with the pathologic reports. The greatest concordance was observed in the 8th decade and the lowest, in the first decade of life. The highest percentage of correct diagnosis was found in the vestibular mucosa, and the lowest in the palate. The highest percentage of agreement was observed for the mucocele and reactive soft tissue lesions, and the lowest for the benign non-odontogenic tumors and epithelial lesions. According to these results, more effective education, the exact clinical examination of the patients and more surgeon- pathologist correlations are necessary.

Statement of Problems: Fluoride is one of the best known and most effective substances in caries prevention; however, excessive consumption of this ion can cause fluorosis. Tea is reported as one of the beverages with high concentration of fluoride and teabags which are frequently used in Iran are rich in this ion. The aim of this study was to determine the fluoride content of some most widely used teabags in Iran. In this descriptive study, six packages of six different brands of tea were purchased. One teabag of each package was placed in a crystal cup and 100cc of boiling distilled water was added. The teabags were shaken for the time recommended by the manufacture and upon removal, buffer TISAB by ratio 1/1 was added to all the solutions. The fluoride content of each sample was measured by fluoride specific electrode and the results were analyzed using SPSS. The fluoride differences between the groups were analyzed using ANOVA test. The mean fluoride content of all the samples was 2/02±1/06 ppm. Maximum and minimum fluoride contents were found in Ahmad teabag (3/27±0/23 ppm) and zarin teabag (0/7±0/02), respectively (p <0.01). This study showed that the fluoride content of teabags is high; hence, heavy tea consumers should use brands with lesser fluoride.

Statement of Problem: Plaque control and its instruction is an important part of dental treatments which guarantees the long term success of the periodontal and dental care. The purpose of this research was to evaluate the efficiency of the oral hygiene instruction given to the patients on the amount of awareness and improving their attitude and practice. Method and Material: For this purpose, a number of 100 patients were selected randomly and instructed oral hygiene methods. The patients filled out a questionnaire including 14 questions derived from OHI-S questionnaire of WHO at the beginning of the study and at the intervals of one and two weeks and 1-month. The plaque index of all the patients was measured by an examiner on the base of O’Leary plaque index. After comparing the pre and post oral health questionnaires, changes in the rate of attitude, awareness and practice of patients were analyzed with paired t-test. One month after oral hygiene instruction, the patients’ awareness and attitude increased by 46% (p = 0.021) and 123% (p = 0.018) respectively. The plaque index decreased by 43.27% (p = 0.018). All of the parameters showed a significant difference from baseline (p <0.05). The results of this study showed that repeated oral hygiene instruction makes a significant improvement on the amount of awareness, attitude and practice of patients in relation to plaque control.

Osteosarcoma is one of the most common primary malignant tumors of the bone in which malignant mesenchymal cells have the capability of producing osteoid or immature bone. Osteosarcoma of the craniofacial bones accounts for 6% to 10% of all the cases and usually occurs in patients older than 20 years of age. As to morphologic and clinical aspects, osteosarcoma can be divided into several subgroups. Central low-grade osteosarcoma is a rare variant of osteosarcoma with minimal cellular anaplasticity. Case Report: The patient was an 18 year old girl who presented with a firm, painless, dome-shaped swelling with buccal and lingual extension of the symphysal region which was misdiagnosed as benign fibro-osseous lesions in two previous recurrences. In the third recurrence, the diagnosis of low-grade osteosarcoma with the foci of high grade transformation was finalized. Because low-grade osteosarcoma of the jaws appears histologically unremarkable, definite diagnosis of this neoplasm requires the study of numerous microscopic sections and correlation of the histological features, patient's history, and clinical and radiographic findings. In this study, the previous misdiagnosis, final diagnosis and treatment of this case have been discussed.