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Showing 3 results for Reliability
Designing and evaluation of validity and reliability of a new device for measurement of axial wall tapering of prepared teeth for fixed crown prosthesis
Hamid Jalali, Farzaneh Farid, Abdolsalam Abobakry, Maryam Mohajerfar,
Volume 25, Issue 2 (4-2012)
Abstract

Background and Aims: The purpose of this study was to design a new device assisting dental students to measure the tapering of the prepared teeth for fixed crown prosthesis in which the desired tapering for better clinical prognosis could be obtained.

Materials and Methods: The designed device in this study had two arms that were placed on two opposite walls of the prepared teeth. To evaluate the validity and reliability of this device, 3 dies with different degrees (13, 29 and 45°) were used and 20 teeth were prepared by dental students with undefined tapering degrees. The measurements of tapering were performed by six last year-dental students in two different time periods. Comparison of errors in measurements on standard dies between observers and between time intervals were analyzed by (Wilcoxon) Paired t-test with a significance level of α=0.05.

Results: For the three dies used in this study, we compared the differences for each measurement taken by observers with the standard taper of the dies. Maximum difference of measurements with true standard die tapering was 1 degree. A number of 6 measurements were under the true standard tapers and 2 measurements were above it. Interclass Correlation Coefficients (ICC) of the first and second measurements on prepared teeth were 97.4 and 97.5, respectively.  There were no significant differences between different observers or two measurements of the same observer in different time intervals (P>0.05).

Conclusion: The results indicated that this device can be valid and reliable for measuring the angle of convergence of the prepared teeth and can be used as an educational device in dental schools as a replacement for previous tapering measurement methods.


Design and validation of an educational questionnaire for evaluation of teachers by students in Shahid Beheshti dental school
Hadi Ghasemi, Arezoo Ebnahmadi, Maryam Moezzyzadeh, Masoud Geramipour,
Volume 28, Issue 4 (1-2016)
Abstract

Background and Aims: Dental students’ evaluation of teachers’ educational activity is crucial for the improvement of dental school’s performance. The process of the evaluation needs a valid and reliable tool. This study aimed to produce and validate a questionnaire for the evaluation of dental school teachers by students.

Materials and Methods: A group of 15 teachers in the Shahid Beheshti dental school gave their opinions regarding the characteristics of an ideal teacher using nominal group technique. These characteristics together with characteristics gathered from similar studies made the base of a questionnaire which later underwent a validity and reliability assessment by means of the calculation of Content Validity Index (CVI), Content Validity Ratio (CVR), and Cronbach’s alpha coefficient.

Results: The preliminary questionnaire included 94 items in four categories naming: ethics, educational capability, practical capability, and managemet. After calculating CVR and CVI for each item, 23 items with CVR<0.33 and 20 items with CVI<0.79 have been excluded from the questionnaire leaving a questionnaire with 54 items. The overall reliability of this questionnaire using Chronbach’s alpha coefficient was 0.96.

Conclusion: Consulting an expert group that are familiar with different aspects of educational performance of faculty teachers, it was concluded that applying various methods for validity and reliability, and considering local culture values are useful for the preparation of the questionnaire for similar studies in Iran.


Validation methods to measure the length of the teeth-canal: A methodological study
, Manoochehr Karami, Ghodrattollah Roshanaei, Abbas Shokri, Namdar Pasandi,
Volume 29, Issue 4 (1-2017)
Abstract

Background and Aims: Acurate measurements of variables are crucial in epidemiological studies. Therefore, even the best design cannot prevent bugs caused due to the lack of reliability and validity measurement in studies. The aim of this study is to determine the validity of teeth-canal measurement.

Materials and Methods: This methodological study used available data of patients referred to dental clinics at Hamadan University of Medical Sciences in Hamadan with sample size or 58 cases in 2012. In order to determine the reliability of measuring the length of canals and introduce the most appropriate measure met of the actual data, Bland-Altman plot and intraclass correlation coefficient (ICC) were used and finally compared.

Results: In this study, the mean ± SD of channel length in the apex locator Root ZX were 21.93 ± 2.28 mm and in X-ray PA were 22.4 ± 2.38 mm. ICC between the length of canals by the apex locator and radiographic in all teeth was 0.989. Bland-Altman plot showed that absolute agreement between the two methods of measurement.

Conclusion: The findings of this study ensure dental professionals that measuring the length of channels by PA method is more practical and easier and prove different approaches of the reliability and validity. However, we recommend using ICC and Bland Altman methods due to their informative nature and consideration of absolute agreement instead of consistency.


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