JOURNAL OF RESEARCH IN DENTAL SCIENCES
Year:2008 | Volume:5 | Issue:2|Papers Count:8

Background and aim: Due to having a lot of malocclusions and the importance of diagnosis of them and specially the present problem of diagnosis such as spending a lot of time to analyse the cephalometry and for answer to this question which can the designed software) CCTA: Computerized Cephalometry Tracer & Analyser (than standard method diagnoses the malocclusions.this research has been done on lat cephalometries which belonged to patients who had Cl l, Cl ll and Cl Ш malocclusions from 1996 until 2008.Materials and Methods: The study was a diagnostic clinical trial design. After designing the CCTA software and continual tracing 120 cases were acquired which 40 were Cl l, 40 were Cl ll and 40 were Cl Ш, then placed a code for each case and all of the informations which belonged to each case were registered in the informational form 1.The user started locating the landmarks without knowing anything about the located landmarks which were located previously by manual tracing and the CCTA software analysed the lat cephalometries and also determined the Cl of malocclusions. The informations were registered in the informational form2. Diagnosis of the CCTA software than absolute diagnosis, sensitivity, specificity and also positive and negative predictive value (PPV & NPV) were evaluated.Conclusions: 120 cases were acquired which 40 were Cl l, 40 were Cl ll and 40 were Cl Ш. Then after a complete comparing between manual tracing and computerized tracing; The sensitivity, specificity and also PPV & NPV and total efficiency were evaluated 100%.Results: Due to our efforts to design this software correctly, and for using a lot of numbers of the cases and doing the complete research, and specificity and sensitivity were 100%, we can strongly say CCTA software not only the successor of the manual tracing but also it is better than it.

Background and aim: One of the problems during orthodontic treatment is insufficient shear bond strength of orthodontic brackets in 30 minutes after bonding which may result in debonding and chair-time consuming. Recently different methods are being used for conditioning and shear bond strength improvement.Since there were lack of articles, this study was designed to evaluate the effect of enamel conditioning with No-Rinse Self-Conditioner in the primary shear bond strength of metal orthodontic brackets in Tehran Azad Dental school Tehran 2008.Materials and Methods: This was an experimental, In-vitro and Single Blind research.60 freshly extracted human premolars were randomly divided into 2 groups, each group consisted of 30 specimens. RMGIC was used to bond all metal brackets to the teeth. One group was conditioned with 10% Polyacrylic acid and in the other one No-Rinse Self-Conditioner was used. The specimens were embedded in acrylic placed in metal rings. Specimens were debonded after 30 minutes with a Universal Testing Machine at a crosshead speed of 1 mm/min. The T-test analysis was used. The Adhesive Remnant Index was determined after observation with 20X magnification. Fisher exact test was used for analyzing.Results: The difference mentioned between shear bond strengths and Adhesive Remnant Index in two groups was not significant (P<0/6).Conclusion: The present findings suggest that No-Rinse Self-Conditioner produces adequate shear bond strength and may facilitate conditioning process and reduces technique sensitivity.

Background and aim: To establish an appropriate dental preventive program, relevant data should be collected from all over the country. The aim of the present study was to find out the care index, treatment needs and DMFT score and its related factors in 12 year – old male and females students studying in Karaj middle schools in 2004.materials and methods: The study was designed as a cross sectional surrey in 4 educational districts of Karaj on 768 students. Study samples were chosen through multi stage random sampling from public and private schools. The questionnaire and study forms were filled through inter view with students and their dental examination. All the examinations were carried out in a well – lit classroom with sterile packed instruments, mask and glove DMFT was calculated by the WHO criteria Some of the related factors were frequency of dental examination, the number ofthe students siblings, mouth breathing, socio economic status of the family the prevalence at problem in samples established and confidence in terval in society was estimated. The role of the related factors was statistically analyzed with chi squarettest.Results: Total samples were 768 people (384 male and 384 female). DMFT was 2.67±2.2 in girls and 3.59±2.59 in boys. Treatment needs and care index was %85/74 and %11/8 in girls and %93.54 and%5.94 in boys respectively.%21.9 girls and%13.55 boys were caries free in this study mothers occupation (P<0/03 in girls and P<0/005 in boys), birth rank (P<0/025 in boys), mouth breathing (p< 0/025), frequency of dental examination (P<0/008 in girls), were significantly related to DMFT. In girls a significant relation ship was found between the type of school and DMFT (P<0/0011).Conclusions: DMFT score was high er than WHO goals specially in boys and education in preventive and treatment fields is recommended. Also, more re search is recommended in the related factors field.

BACKGROUND AND AIM: Marginal seal is one of the most important factors for a successful restoration.It is commonly accepted that microleakage can be reduced by utilization of an incremental filling procedure. The purpose of this study was to determine the effect of different layering techniques on microleakage in direct class II composite restorations.METHODS & MATERIALS: 30 freshly extracted human premulars were used to prepare classll cavities, divided into 3 groups of 10 each (H, O, V).Each cavity was restorated with composite (Z250, 3M, ESPE) using 3 different filling technique.Group H was filled in horizontal /Group O was restorated by an oblique incremental technique and group V by a vertical technique.Then teeth were immersed in Agnitrate 50% byW. And prepared for studing under the steeormicroscope 20×. The result of microleakage was compared among groups by kruskal-wallis test. (Pv>0.05) RESULT: There was no signtificant difference between the vertical and oblique incremental filling comparing with the horizontal technique.

Background and aim: According to the importance of avoiding injuries to the neurovascular bundles in certain surgical procedures (e.g. placement of implants), an accurate location of the mandibular is necessary. The aim of the present study was to evaluate and compare between the accuracy of the panoramic spiral tomography in location of the mandibular canal.Methods and materials: In this study, by means of the odonto Rama 2000 (Traphy, French), panoramic radiographies were taken and by means of Cranex tome multifunctional unit (orion corporation Sordex, finland), tomographic slices were taken at 3 different location in each posterior mandible segments (distal to the mental foramen). Then the dry mandibles were sectiond at these 3 sites with specialized desiged drill. The fallowing 2 measurments were performed both on the panoramic radiographies (A, B), tomograms (A’, B’) and the bone sections (A’’, B”) at the 3 sites.Findings: The research was on 6 dry mandibles (36 sites). We found an average mean difference of 3.9 mm with a standard deviation of 1.57 in panoramic radiography and an average mean differences of 0.21mm with a standard deviation of 0.21 in spiral tomography. The report of data showed that 16.4% of cases are in+_0.5mm and 41.4% of cases are in+_1mm (overstimate and underestimate) in panoramic radiography and 94.6% of cases are in+_0.5mm and 97.3% of cases are in+_1mm in spiral tomography. ICC in panoramic radiography was 0.6932 and in spiral tomography was 0.9982 (P<0.001) Conclusion: and recommendation: Spiral tomography using the Cranex tome multifunctional x-ray unit provides accurate information and sufficient detailes or preoperative planning of implant in the posterior mandible and this method is recommended for surgures, periodontists and prosthodontists.

Background and aim: Due to various range of microorganisms, causing oral and maxillofacial infection, correct selection of appropriate antibiotics is important consideration for management.Materials and method: An analytic-descriptive cross sectional study of 36 patients referring to the oral and maxillofacial ward of the azad university because of facial abscess. Abscess was aspirated by a sterile syringe and then sent to the laboratory for antibiotic sensitivity testing. data was analyzed using with spss soft ware and fisher exact and chi square tests.Result: Hemolytic and nonhemolytic streptococcus were the most prevalent microorganisms found.ciprofloxacin and ceftizoxin were the most effective antibiotics found. nalidixic acid and cloxacillin had no effect on these microorganisms.Conclusion: Penicillin and amoxicillin are the first choice for the oral and maxillofacial infections. The second choice is ceftizoxime and ciprofloxacin, cephalothin, gentamicin and ceftriaxone.

Background and aim: According to the importance of avoiding injuries to the neurovascular bundles in certain surgical procedures (e.g. placement of implants), an accurate location of the mandibular is neccessary. The aim of the present study was to evaluate and compare between the accuracy of the panoramic spiral tomography in location of the mandibular canal.Methods and materials: In this study, by means of the odonto Rama 2000 (Traphy, French), panoramic radiographies were taken and by means of Cranex tome multifunctional unit (orion corporation Sordex, finland), tomographic slices were taken at 3 different location in each posterior mandible segments (distal to the mental foramen). Then the dry mandibles were sectiond at these 3 sites with specialized desiged drill. The fallowing 2 measurments were performed both on the panoramic radiographies (A, B), tomograms (A’, B’) and the bone sections (A’’, B”) at the 3 sites.Findings: The research was on 6 dry mandibles (36 sites). We found an average mean difference of 3.9 mm with a standard deviation of 1.57 in panoramic radiography and an average mean differences of 0.21mm with a standard deviation of 0.21 in spiral tomography. The report of data showed that 16.4% of cases are in+_0.5mm and 41.4% of cases are in+_1mm (overstimate and underestimate) in panoramic radiography and 94.6% of cases are in+_0.5mm and 97.3% of cases are in+_1mm in spiral tomography. ICC in panoramic radiography was 0.6932 and in spiral tomography was 0.9982 (P<0.001) Conclusion and recommendation: Spiral tomography using the Cranex tome multifunctional x-ray unit provides accurate information and sufficient detailes or preoperative planning of implant in the posterior mandible and this method is recommended for surgures, periodontists and prosthodontists.

Background and aim: The most important factor in the success of restoration is marginal fitness. If there is not an appropriate marginal fitness between tooth and restorations it may cause carries in the marginal area because of the food and debris in the marginal area cause gingivitis and margin discoloring and in sever cases it will have increase of pocket depth and loss of attached gingival from this problem caused this research.Material & Methods: This is experimental research, the samples are 20 and there are chooses simple randomize. The mentioned marginal design were designed on a standard die by machines. Then impressions were provided from dies, and after making the restoration by electroforming method, the gap die and restoration measured by photo esterio microcope and T. Test.Conclusion:X`  shoulder: 24.42 X`   sloping shoulder: 13.92 P.value=0.05 According to the P-value in comparing between X`   of this two group of marginal design, there was significant difference.Results: According to the significant difference, have the difference act about marginal fitness metoceramic restoration and sloping shoulder have better marginal fitness than shoulder in electroforming method.