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Background and purpose: Digital radiography has led to many improvements in radiology. Despite many advantages there are different ideas in determining anatomical landmarks which results in some errors in cephalometric analyses. The aim of this study was to determine the degree of identification differences of anatomical landmarks by conventional and digital lateral cephalometric techniques using manual tracing of human skulls. Material and Methods: This descriptive-analytical study was conducted in 17 cases of human skulls in which metal radiopaque markers were attached to 9 landmarks as follows: N, S, ANS, PNS, A, B, Pog, the most inferior point of lower mandibular border, and Go. Conventional and digital lateral cephalograms were obtained from each skull with and without markers. The two cephalograms without markers were traced for landmarks by three orthodontists. Any difference between these landmarks and those of cephalograms with markers, were recorded and analyzed by student t-test. Results: The level of differences in S point was not statistically significant along both x and y coordinates. The measurement differences for the ANS and PNS points obtained by both radiographic methods were significant along the x coordinate but not significant along the y coordinate. Also, the measurement differences for the most inferior point of lower mandibular border, A, B, and Go points along both x and y coordinates were observed to be statistically significant. The measurement difference obtained for the Pog point was significant along the y coordinate and non-significant along the x coordinate. Conclusion: The difference in landmark identification between the two digital and conventional lateral cephalometric techniques was statistically significant for some points on both dimensions, however, the difference was not clinically significant.

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Background and purpose: Unusual enlargement of nose and pharyngeal (nasopharynx) can disrupt the flow of air through the nose. The aim of this study was to investigate the cephalometric parameters in the upper airways.

Materials and methods: A retrospective descriptive study was performed using the digital lateral cephalometric radiographs of 32 adults with class I (CL I) malocclusion and no history of night apnea. The radiographs were obtained from the archives in Qazvin Orthodontics Department of Dentistry School and private clinics. Coefficient of variations and Pearson correlation were calculated in SPSS. 

Results: There was positive Significant correlation (r= 0.761) between tongue length and tongue height, length of the soft palate, and maximum thickness of the soft palate but negative significant correlation was found between tongue length and hypo pharnzhyal air space (r= -0.422) (P= 0.01). There was positive significant correlation (r= 0.444) between tongue height and length of the soft palate and maximum thickness of the soft palate. Also, there was positive significant correlation between over pharyngeal air space and hypo pharyngeal air space and posterior air space (r= 0.551) (P= 0.014). There was positive significant correlation between hypo pharyngeal air space and posterior air space, vertical position of vallecula, and horizontal position of vallecula (P= 0.017). Posterior air space had a positive significant correlation with horizontal position of vallecula but had a negative significant correlation with length of the soft palate. There was positive significant correlation between length of the soft palate and maximum thickness of the soft palate, and vertical position of vallecula and horizontal position of vallecula.

Conclusion: There was no significant difference in cephalometric parameters of the upper air ways in adults in Qazvin with CL I malocclusion. Genetic and environmental effects are the most important factors in these cases.

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     Background and purpose: Respiratory function of patients is a major part of orthodontic diagnosis and treatment planning. It is affected by the dimensions of the pharyngeal airway. In this study, these dimensions were compared in patients with different skeletal patterns.
Materials and methods: This cross-sectional descriptive-analytical study was performed studying the cephalograms of patients attending the Orthodontic Clinic affiliated with Mazandaran University of Medical Sciences 2016-17. After tracing, 144 cephalograms were divided into three groups: class I, II, and III (n= 48 per group) based on the ANB angle. The nasopharyngeal, oropharyngeal, and hypopharyngeal dimensions were measured. Data were analyzed using SPSS V24.
Results: The highest mean dimensions amongst nasopharyngeal, oropharyngeal, and hypopharyngeal spaces were found in class I (21.25mm), III (10.49mm), and III (15.89mm), respectively. There was no significant difference between class I and II in the nasopharyngeal space (P=0.108). There were significant differences in the mean dimensions of all three spaces studied between class I and III and class II and III (P <0.05).
Conclusion: Airway dimensions seem to vary among different classes of sagittal malocclusion. The dimensions of oropharyngeal and hypopharyngeal airways decrease with increase in ANB angle, but the dimensions of the nasopharyngeal airway are not associated with the changes in ANB angle and are higher in people with class I skeletal occlusion.

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Background and purpose: Dental and skeletal features, unlike soft tissues, remain unchanged in events where most body tissues are destroyed such as car accidents, plane crash, crimes, etc. Panoramic and lateral cephalometric radiographs can provide useful information about dental and cephalometric indicators in human identification.
Materials and methods: A cohort retrospective study was carried out in five stages, including collecting the samples, using a specific tooth counting system, identifying the landmarks in panoramic radiographs and designing a dental formula, designing anatomical formula with cephalometric indicators and identifying operator errors, and matching and data analysis.
Results: We studied 180 people, including 97 (54%) women and 83 men aged 15-59 (mean age= 25.5) years in Tehran. Average indexes of missing (M), filled (F), Root Canal Therapy (RCT) teeth, crown (C), (Body/Go-Go), (Mf-Mf/Mf-Go(R+L)), De, P, ER, Go in lateral Cephalometry, SNA, SNB, Basal, N-Ans-Me, Ans-Pns/Go-Me, and S-Go/N-Me were not significantly different between cases by comparing the graphs before and after treatments (P>0.05). Examination of average indices of implant and dilacerated teeth in general and without considering the number of teeth, did not show a significant difference when the pre/post-treatment graphs were compared (P>0.05). In examining the Co-Ans/Co-Gn, Go in panoramic graph, (S-N/S-Ba) and S-N-Ba, no significant difference was observed between the cases (P>0.05).
Conclusion: Panoramic, lateral cephalometric graphs and designing creative formula can be used in human identification.