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Background: This study was aimed to assess the implant-related anatomical landmarks in the mandibular interforaminal region in an Iranian population using cone-beam computed tomography (CBCT). Methods: In this retrospective cross-sectional study, 378 CBCT images of the mandible were evaluated for the presence of the incisive canal, anterior loop of the inferior alveolar nerve (IAN), mandibular canal, mental foramen, and incisive canal. The effect of age and gender of patients on the abovementioned variables was also evaluated. Data were analyzed using independent t-test, analysis of variance, and Chi-square test. Results: The anterior loop and the incisive canal were present in 36.24% and 97.62% of the cases, respectively. The mean length of the anterior loop and the incisive canal was 2.70 ± 1.20 mm and 12 ± 3.29 mm in the right, and 2.86 ± 1.24 mm and 12.21 ± 3.38 mm in the left side, respectively. The mean diameter of the mental foramen and incisive canal was 4.25 ± 1.08 mm and 1.89 ± 0.46 mm in the right, and 4.21 ± 1.02 mm and 1.94 ± 0.45 mm in the left side, respectively. The descending path was the most common path of the incisive canal. The distance from the incisive canal to the buccal plate and inferior border of the mandible was significantly shorter in females (P < 0.001). Conclusion: Considering the high variability and clinical significance of the incisive canal and anterior loop of the IAN, and their high prevalence, it is recommended to assess the presence/absence of these structures in the interforaminal region of the mandible on CBCT scans before surgical procedures in this region.

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Background: This study aimed to assess the correlation of ponticulus posticus (PP) with dentofacial skeletal patterns on lateral cephalograms of an Iranian population. Methods: This retrospective study evaluated 1000 lateral cephalograms of 690 females and 310 males. Demographic information of patients was recorded, and two observers evaluated all radiographs for the presence of PP. The dentofacial skeletal pattern was also determined as Class I, II, or III. Disagreements were resolved by discussion with a third observer. Data were analyzed using the Chi-square test. Results: The mean age of patients was 19.47 ± 8.37 years (range 7-64 years). The prevalence of PP was 38.3%. PP had a significant correlation with gender (P = 0.022) such that PP was more common in males (43.5%). No significant correlation was noted between PP and age or dentofacial skeletal pattern (P > 0.05). Conclusions: PP was relatively common in our study population. PP had no correlation with age or dentofacial skeletal pattern of patients.

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BACKGROUND: This study aimed to compare the pharyngeal airway volume in class I,II and III skeletal malocclusion patients using cone beam computed tomography (CBCT). MATERIAL AND METHODS: This retrospective, cross sectional study was conducted on lateral cephalograms of 71 patients derived from their CBCT scans. Using the ANB angle, the patients were divided into class I,II and III malocclusion. Two observers used Dolphin 3D software to calculate the pharyngeal airway volume, airway area, minimum axial area, minimum area location, airway length and morphology. Data were analyzed using one-way ANOVA, Kruskal-Wallis test, Tukey's test, Spearman's correlation coefficient and multiple regression analysis. RESULTS: The three skeletal classes were significantly different in airway volume, minimum axial area, mean airway area and airway morphology (P<0.05). Significant differences were found in airway volume and mean airway area between class II and III patients (P<0.05). The minimum axial area and airway morphology in class III patients were greater than those in class I and II patients (P<0.05). Every one unit increase in the ANB angle decreased the airway volume by 0.261 units. The effect of ANB angle on airway volume was statistically significant and it was shown that one unit increase in the angle decreased the airway volume by 453.509 units. CONCLUSIONS: A significant correlation exists between the skeletal facial pattern and upper airway dimensions. In our study, the total airway volume and the mean airway area of class III patients were larger than those in class II patients. Key words:Cone-Beam computed tomography, malocclusion, pharyngeal airway volume.

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OBJECTIVES: This study aimed to assess the effect of head position on the accuracy of transverse measurements of the maxillofacial region on CBCT and conventional posteroanterior (PA) cephalograms. The second objective of this study was to find skull positions with the greatest and smallest effect on transverse measurements in the maxillofacial region. METHODS: PA cephalograms and CBCT scans were obtained from 10 dry human skulls in 7 positions, namely the central position, 10° and 20° rotations, 10° and 20° tilts and 10° and 20° tips. The CBCT scans were converted to PA cephalograms on which distances from six landmarks, namely the nasal cavity, zygomatic arch, jugale, antegonion, condylion and zygomaticofrontal suture to the mid-sagittal plane, were measured on both sides using Dolphin two-dimensional software. The paired t-test was used to compare the mean values separately in each position (for each landmark) with the gold standard (central skull position). The interclass correlation coefficient and the Bland-Altman plot were used to compare the mean values measured by two observers. RESULTS: The mean values of the distances measured on CBCT PA cephalograms were greater than those measured on conventional PA cephalograms; this difference was statistically significant for some landmarks (p < 0.005). The rotated position (as compared with the central position) caused the greatest change in values for most landmarks on both sides (p < 0.005). CONCLUSIONS: The CBCT PA cephalogram was more accurate than the conventional PA cephalogram, and landmarks farther from the midline exhibited greater changes on cephalograms compared with those closer to the midline. Patients are at risk of improper positioning when undergoing extraoral radiography such as PA cephalograms. Changes in head position may affect the transverse measurements and thus the treatment plan.

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Article Incorrect patient positioning and the resultant image distortion occur in many radiographic examinations. This study aimed to assess the effect of tilting, rotation and tipping of the head on the accuracy of maxillofacial transverse measurements made on cone beam computed tomography (CBCT) scans. The CBCT scans were obtained in central position of 10 dry human skulls. Using three-dimensional (3D) Dolphin software, six positions namely 10° and 20° tilts, rotations and tips were reconstructed of central position. Transverse distances between landmarks were measured on 3D scans and the skulls. The intraclass correlation coefficient (ICC) and the Bland-Altman plot were used to compare the mean values measured by the two observers. For most landmarks, no significant differences were noted between the mean transverse distances measured in the six positions and those measured in central position on 3D scans (p>0.005). In conclusion, all measurements of transverse distances made on 3D scans in different positions were underestimated compared to the actual values measured on the skull.

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Article Incorrect patient positioning and the resultant image distortion occur in many radiographic examinations. This study aimed to assess the effect of tilting, rotation and tipping of the head on the accuracy of maxillofacial transverse measurements made on cone beam computed tomography (CBCT) scans. The CBCT scans were obtained in central position of 10 dry human skulls. Using three-dimensional (3D) Dolphin software, six positions namely 10° and 20° tilts, rotations and tips were reconstructed of central position. Transverse distances between landmarks were measured on 3D scans and the skulls. The intraclass correlation coefficient (ICC) and the Bland-Altman plot were used to compare the mean values measured by the two observers. For most landmarks, no significant differences were noted between the mean transverse distances measured in the six positions and those measured in central position on 3D scans (p>0.005). In conclusion, all measurements of transverse distances made on 3D scans in different positions were underestimated compared to the actual values measured on the skull.

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Objective: Mandibular foramen (MF) is located on the internal surface of the ramus through which blood vessels and nerves pass. Determination of the anatomic position of the MF is very important in inferior alveolar nerve block anesthesia (IANBA), ramus osteotomy and surgical procedures of the posterior angle of mandibular ramus. The aim of this study was to determine anatomic position of the MF using anatomic landmarks on the three dimensional CBCT images. Material and Methods: A total of 103 CBCT images was evaluated. The NNT Viewer software program was used to measure the distances between the lines tangent on the MF periphery and the anterior border of the ramus, the posterior border of the ramus, the inferior border of the mandible, and the coronoid notch in mm by to age and gender. Results: The results showed a slight difference in anatomic dimensions between the right and left sides, with no significant differences. The anatomic dimensions of the MF on both sides were a little bigger in males than in females. There were no significant differences in the anatomic dimensions of superior inferior and anterior-posterior dimensions of the left and right sides in different age groups. Conclusion: No significant changes occur in the position of the MF with age. The anatomic differences between males and females should be taken into account during IANBA procedures. Males have bigger jaws than females; therefore, there is a longer distance between the MF and the anatomic landmarks evaluated...

Objetivo: O forame mandibular (FM) localiza-se na superfície interna do ramo mandíbula, onde passam vasos sanguíneos e nervos. A determinação da posição anatômica do FM é muito importante para anestesia por bloqueio do nervo alveolar inferior (ABNAI), durante osteotomiano ramo da mandíbula e para procedimentos cirúrgicos do ângulo posterior do ramo mandibular. O objetivo deste estudo foi determinar a posição anatômica do FM utilizando referências anatômicas em imagens tridimensionais de CBCT. Material e Métodos: Um total de 103 imagens de CBCTforam avaliadas. O programa de software NNT Viewer foi utilizado para medir as distâncias em milímetros entre as linhas tangentes na periferia do FM e borda anterior do ramo, borda posterior do ramo, borda inferior da mandíbula e processo coronóide, em relação à idade e o gênero. Resultados: Os resultados mostraram uma ligeira diferença de dimensões anatômicas entre os lados direito e esquerdo, sem diferenças significativas. As dimensões anatômicas do FM em ambos os lados foram um pouco maior no sexo masculino do que no feminino. Não houve diferenças significativas nas dimensões anatômicas superior-inferior e ânteroposterior, tanto do lado direito quanto esquerdo,em diferentes faixas etárias. Conclusão: Mudanças significativas na posição do FM não são observadas em função da faixa etária. As diferenças anatômicas entre homens e mulheres devem ser levadas em consideração durante procedimento ABNAI. Mandíbulas maiores são encontradas no gênero masculino, portanto, há uma maior distância entre o FM e as referências anatômicas avaliadas...

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Objective: Measurement of root canal length is one of the most important stages of endodentic treatment, and any error at this stage can lead to the failure. This study aimed to compare conventional and digital intraoral radiography in measurement of root canal length. Material and Methods: In this study, 35 single-canal maxillary teeth were collected. Access cavities were prepared. An endodontic number 10#K- file was introduced into the canal, until the tip was visible at the apical foramen and the actual canal length (gold standard) was determined. After acquisition conventional radiographs using E-Ektaspeed and F-Insight film (Eastman-Kodak Co. Rochester, NY, USA) and digital radiographs using Photostimulable Phosphor Plates(PSP) (Soredex, Helsinki, Finland) and Charge Coupled Devices (CCD)(RVG, Trophy,NY,USA). they were examined separately with a two-week interval by two oral and maxillofacial radiologists. The data were analyzed with ANOVA and Tukey’s tests using SPSS-19 software (SPSS Inc., Chicago, IL, USA). Result: No statistically significant difference was observed between different radiographies, and different observers (P > 0.05). Nevertheless, in comparison with the gold standard, in all cases, the F-speed conventional radiography and the digital CCD radiography showed the highest and the lowest accuracy, respectively. Also, the PSP and the E-speed conventional radiography were in the second and third order of accuracy, respectively. Conclusion: The use of digital radiography does not improve the accuracy of the root canal length measurement,but the digital technique has advantages,such as the reduced patient exposure, eliminating the time consuming processing stages, and producing fast images...

Objetivo: A medição do comprimento do canal radicular é uma das etapas mais importantes de tratamento endodôntico, e qualquer erro nesta fase pode levar ao fracasso. Este estudo teve como objetivo comparar a radiografia intra-oral convencional e digital na medida do comprimento do canal radicular.Material e Métodos: Neste estudo, 35 dentes superiores com canal único foram coletados. Cavidades de acesso foram preparadas. Uma lima endodôntica tipo K, número 10 foi introduzida no canal, até que a ponta era visível no forame apical e o comprimento do canal real (padrão ouro) foi determinada. Após a aquisição de radiografias convencionais, utilizando os filmes E-Ektaspeed e F- Insight (Eastman Kodak Co.,Rochester, NY, EUA) e radiografias digitais utilizando placas foto estimuláveis de fósforo (PSP) (Soredex, Helsinki, Finlândia) e dispositivos de acoplamento (CCD) (RVG, Troféu, NY, EUA), as mesmas foram examinadas separadamente com um intervalo de duas semanas, por dois radiologistas oral maxilofaciais. Os dados foram analisados pelos Testes de ANOVA e Tukey utilizando o software SPSS-19 (SPSS Inc., Chicago, IL, EUA). Resultados: Não houve diferença estatisticamente significativa entre as diferentes radiografias, e observadores diferentes (P > 0,05). No entanto, em comparação com o padrão-ouro, em todos os casos, a radiografia convencional e a radiografia digital CCD apresentaram o maior e a menor precisão, respectivamente. Além disso, a PSP e a radiografia convencional estavam na segunda e terceira ordem de precisão, respectivamente. Conclusão: O uso da radiografia digital não melhora a precisão da medição do comprimento de canal, mas a técnica digital tem vantagens, tais como a exposição do paciente reduzida, eliminando o demorado estágio de processamento, produzindo assim, imagens mais rápidas...

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Objective: The aim was to investigate the accuracy of linear measurements of the mandibular ridge recorded using two CBCT systems. Material and Methods: Eleven human dry skull were used in which mandibles were chosen to measure width and height in 6 sites. Before scanning, the points were marked using barium sulfate radiopaque contrast media. Mandible imaging was done using two systems: Newtom3G and Cranex3D. Alveolar ridge dimensions were recorded by two observers under uniform condition using special software for each system. The measurement errors and inter-examiner reliability were calculated for each modality and compared with each other and analyzed via SPSS software version 18. The level of significance was set at P < 0.05. Results: The overall mean was 0.08 mm for Cranex system and 0.5 for Newtom system. The mean of two systems had no statistically significant difference in comparison with each other or with the gold standard. The statistical analysis showed high inter-observer reliability (P < 0.05). Conclusion: CBCT is highly accurate and reproducible in linear measurements in the different areas of the maxillofacial region.

Objetivo: O objetivo deste estudo foi investigar a acurácia de medidas lineares do rebordo mandibular utilizando dois sistemas de TCFC. Material e Métodos: Onze crânios secos humanos foram utilizadas e seis regiões das mandíbulas foram escolhidos para mensuração da largura e da altura. Antes da digitalização, os pontos foram marcados com contraste radiopaco de sulfato de bário. Imagens da mandíbula foram realizadas usando dois sistemas: Newtom3G e Cranex3D . As dimensões rebordo alveolar foram determinadas por dois observadores em condições uniformes utilizando software específico para cada sistema. Os erros de medição e confiabilidade interexaminadores foram calculados para cada modalidade, utilizando o software SPSS versão 18, e comparados entre si. O nível de significância adotado foi p < 0,05. Resultados: A média geral para o sistema Cranexfoi de 0,08 mm e 0,5 para o sistema de Newton. As médias dos dois sistemas não apresentaram diferença estatisticamente significativa em comparação entre si ou com o padrão-ouro. A análise estatística mostrou alta confiabilidade interexaminador (p < 0,05). Conclusão: TCFC é altamente precisa e reprodutível em medidas lineares nas diferentes áreas da região maxilofacial.

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