How Does Voxel Size of Cone-beam Computed Tomography Effect Accurate Detection of Root Strip Perforations

Introduction: Our study aimed to assess the diagnostic accuracy of different voxel sizes for cone-beam computed tomography (CBCT) when detecting strip perforations of variable sizes. We used 0.2 and 0.3 mm3 voxel for detecting root strip perforations. Methods and Materials: This was an in vitro study conducted on 155 extracted humans' mandibular first molars. The teeth were randomly divided into five groups (n=31). Perforation were not induced in the control group. In the remaining four groups, strip perforations of 0.5, 1, 1.5, and 2 mm diameters were created in the mesiolingual canal using #3 Gates Glidden drills. The CBCT scans were taken first with a 12×9 cm field of view (FOV), 90 kVp, 4 mA, and 0.2 mm3 voxel size for 24 sec and then with a 12×9 cm FOV, 90 kVp, 2 mA, and 0.3 mm3 voxel size for another 24 sec. Two observers evaluated the images and reported the largest diameter of perforations. The results were compared with the gold standard values (determined by an electronic digital caliper) using statistical methods, including the kappa coefficient and generalized estimating equation (P<0.05). Results: Based on the findings of our study, the inter-observer agreement ranged from 58-100%, while the intra-observer agreement was reported to be around 100%. The difference in accuracy between 0.2 and 0.3 mm3 voxel sizes was not statistically significant (P>0.05). In addition, the accuracy of detecting different perforation sizes in the CBCT did not follow a specific pattern.  Conclusion: This in vitro study showed that CBCT is a reliable diagnostic tool, and even in lower dosages of 0.3 mm3 voxel size, image resolution and diagnostic accuracy was not affected. Moreover, smaller root perforations could be detected as accurately as larger ones with CBCT

A comparison of oral omeprazole and intravenous cimetidine in reducing complications of duodenal peptic ulcer

BACKGROUND: Gastrointestinal bleeding is a common problem and its most common etiology is peptic ulcer disease. Ulcer rebleeding is considered a perilous complication for patients. To reduce the rate of rebleeding and to fasten the improvement of patients' general conditions, most emergency departments in Iran use H2-blockers before endoscopic procedures (i.e. intravenous omeprazole is not available in Iran). The aim of this study was to compare therapeutic effects of oral omeprazole and intravenous cimetidine on reducing rebleeding rates, duration of hospitalization, and the need for blood transfusion in duodenal ulcer patients. METHODS: In this clinical trial, 80 patients with upper gastrointestinal bleeding due to duodenal peptic ulcer and endoscopic evidence of rebleeding referring to emergency departments of Imam and Sina hospitals in Tabriz, Iran were randomly assigned to two equal groups; one was treated with intravenous cimetidine 800 mg per day and the other, with 40 mg oral omeprazole per day. RESULTS: No statistically significant difference was found between cimetidine and omeprazole groups in regards to sex, age, alcohol consumption, cigarette smoking, NSAID consumption, endoscopic evidence of rebleeding, mean hemoglobin and mean BUN levels on admission, duration of hospitalization and the mean time of rebleeding. However, the need for blood transfusion was much lower in omeprazole than in cimetidine group (mean: 1.68 versus 3.58 units, respectively; p < 0.003). Moreover, rebleeding rate was significantly lower in omeprazole group (15%) than in cimetidine group (50%) (p < 0.001). CONCLUSION: This study demonstrated that oral omeprazole significantly excels intravenous cimetidine in reducing the need for blood transfusion and lowering rebleeding rates in patients with upper gastrointestinal bleeding. Though not statistically significant (p = 0.074), shorter periods of hospitalization were found for omeprazole group which merits consideration for cost minimization

Evaluation of X-ray Protection Methods Used in Dental Offices in Tabriz in 2005-2006

&lt;p&gt;&lt;strong&gt;Background and aims.&lt;/strong&gt; The aim of this study was to evaluate x-ray protection methods in dental offices in Tabriz. &lt;/p&gt;&lt;p&gt;&lt;strong&gt;Materials and methods.&lt;/strong&gt; In this study 142 dental offices were evaluated. A questionnaire-based method was used. The data was analyzed by descriptive methods. &lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results.&lt;/strong&gt; The least commonly used methods were leaded walls (4.9%) and film badges (16.9%) and the most commonly used methods were lead partitions (67.6%) and position-distance rule (68.3%). The most commonly used patient protection devices were E-speed films (84.5%) and long collimators (66.2%). The least commonly used methods, in this respect, were automatic processors (2.1%) and rectangular collimators (0%). &lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusion.&lt;/strong&gt; Regarding protection methods for the patient, results did not conform to international standards. Mostly, manual processing was used, resulting in extra radiation dose to patients. The methods which reduce the received dose of patients were disregarded in offices compared to educational centers, necessitating optimization of educational programs in these fields.&lt;/p&gt

Influence of the Display Monitor on Observer Performance in Detection of Dental Caries

&lt;p&gt;&lt;strong&gt;Background and aims.&lt;/strong&gt; Digital imaging continues to gain acceptance in dentistry and video display used for this becomes important. The aim of this study was to assess the influence of the display monitor on observer performance on caries detection. &lt;/p&gt;&lt;p&gt;&lt;strong&gt;Materials and methods.&lt;/strong&gt; Artificial enamel lesions were created in 40 extracted teeth at random using 1/4 and 1/2 round burs. Teeth were mounted in dental stone blocks to simulate a hemi-dentition. Approximate exposures were recorded at 70 kVp using a Planmeca (Planmeca Co, Helsinki, Finland) digital imaging system. Three oral and maxillofacial radiologists rated each image on a five-point scale for the presence or absence of lesion. Radiographic images were viewed on the following monitors: (1) LG Flatron 700p (LG Electronics Co., South Korea); (2) Samsung Magicgreen (Samsung Electronics Corp., South Korea); (3) Hansol 710p (Hansol Electronics Corp., South Korea) and (4) Toshiba satellite laptop (Toshiba Computer Corp., Philippines). Examiners were allowed to magnify and adjust density and contrast of each image at will. Receiver Operating Characteristic (ROC) analysis was performed. Data was subjected to repeated measures analysis of variance and ordinal logistic regression to test for significance between variables and to determine odds ratios. &lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results.&lt;/strong&gt; Mean ROC curve areas ranged from 0.8728 for the LG monitor to 0.8395 for the Samsung. Repeated measures analysis of variance showed significant differences between observers (P&lt; 0.0001), lesion size (P&lt; 0.0001), examiner/monitor interaction (P&lt; 0.033) and examiner/block interaction (P&lt; 0.013). However, no significant difference was found between monitors. &lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusion.&lt;/strong&gt; This study suggests that observer performance is independent of the visual characteristics of the display monitor.&lt;/p&gt

The Role of Arsenic Treatment after Induction in Alternative and Long-Term Cases for the Prevention of Acute Promyelocytic Leukemia Recurrence

&quot;nIntroduction: Arsenic has been used as an effective medicine in the treatment of severe promyelocytic leukemia in recurrence and resistance cases toward ATRA. In this study, it has been used as induction and maintenance therapy after remission. &quot;nMethod &amp;amp; Material: We studied 31 patients diagnosed by APL. Arsenic was started at a dose of 0.15 mg/kg (daily) until patient&amp;rsquo;s bone marrow remission.(1) We started Arsenic as a consolidation therapy after 28 days rest and then we continued the treatment with Arsenic each 3-4 months during 2 years for 14 days. &quot;nResults: 4 patients died (12.9%) during the first 15 days of treatment. 27 patients (87%) went into remission. 2 patients refused the continuation of treatment regardless the remission. 25 patients received a long term treatment. The disease of 3 out of 25 patients recurred during follow -up period. &quot;n1 patient died during the treatment after recurrence and 3 others given ATRA &amp;amp; Arsenic went into remission. Now, It has been past 2 months since the end of their remission. &quot;nThe recurrence appeared in the form of full involvement of thoraco-lumbar which was observed as an extensive tumor on MRI and was found to cover the mentioned area. &quot;n1 patient faced CNS fungal infection during neutropenia period and then recovered after operation and proper treatment; however his vision was severely damaged. &quot;nAs 4 patients faced leukocytosis over 1000/000ml, we were obliged to discontinue arsenic for 3-4 days and chemotherapy by Danurobicine was prescribed for 2 days. &quot;nThe patient&amp;rsquo;s follow-up and the median survival time were 54 and 48 months, respectively. The overall survival was 80.6%. &quot;nDiscussion: Arsenic as the first line therapy for APL is an effective treatment .Consistent long- term therapy with intervals will reduce the risk of disease recurrence. &quot;n&amp;nbsp; &quot;nKey word: APL, Arsenic Trioxide