Evaluation of the effect of direct sinus lift surgery on maxillary sinus volume by Mimics software.

Introduction: Sinus lift surgery allows sufficient volume of bone to be created in the posterior part of the maxilla. The aim of this study was to investigate the changes in maxillary sinus volume after a sinus lift and the rate of increase in ridge height at the site of the graft. Methods: Eleven patients were chosen for sinus lift from among those who were referred to the radiology department for implant placement in the posterior region of the maxilla and whose bone height at the posterior of the maxilla was less than 4 mm on the cone-beam computed tomography (CBCT) image. The sinus volume was measured after importing the CBCT file in DICOM format into Mimics software. After determining the sinus volume, the patients underwent sinus lift surgery, and the amount of material used during the surgery was measured. After the time required to repair the area, the CBCT image was taken again. Then, the changes in the volume of the maxillary sinus and the increase in the height of the maxillary ridge at the surgical site were calculated. Then, the second stage of the surgery was performed to place the implant at the implant site. Results: For an average of 1.40 cm3 of material, the rate of increase in ridge height was 10.52 mm, and the average change in sinus volume was 1.19 cm3. Conclusions: CBCT images and Mimics software have many applications in examining and predicting parameters before and after sinus lift surgery.

In Vitro Diagnostic Accuracy and Agreement of Dental Microscope and Cone-Beam Computed Tomography in Comparison with Microcomputed Tomography for Detection of the Second Mesiobuccal Canal of Maxillary First Molars.

Objectives: The percentage of failure of endodontically treated maxillary molars is relatively high; one main reason is that the second mesiobuccal canal (MB2) is missing. Some techniques have been proposed for detection of the MB2. This study was aimed at assessing the diagnostic accuracy and agreement of the dental microscope and cone-beam computed tomography (CBCT) in comparison with microcomputed tomography (micro-CT) for detection of the MB2 of maxillary first molars in vitro. Materials and Methods: This in vitro, experimental study evaluated 71 permanent maxillary first molars that were stored in 100% humidity at room temperature. The teeth were mounted in 9 silicone dental arches to the level of their cementoenamel junction (8 teeth in each arch). The blocks underwent CBCT in a XG3D scanner. Access cavity was then prepared, and the teeth were inspected by a surgical microscope for negotiation of the MB2. Also, micro-CT images were obtained from the teeth to serve as the gold standard. CBCT and micro-CT images were observed by two examiners twice with a 2-week interval. Results: The frequency of the MB2 detected by dental microscope was significantly lower than micro-CT (P < 0.001) and CBCT (P = 0.008); no significant difference existed between micro-CT and CBCT in this respect. The sensitivity, specificity, positive predictive value, and negative predictive value of CBCT for detection of MB2 were 92.6%, 100%, 100%, and 81%, respectively. Conclusion: CBCT is superior to the dental microscope for detection of the MB2 of maxillary first molars and can be used for this purpose in the clinical setting with adequate accuracy.

Association of Inflammatory Periapical Lesions with Maxillary Sinus Abnormalities: a Retrospective Cone-Beam Computed Tomography Study.

STATEMENT OF THE PROBLEM: Odontogenic infections such as periapical lesions (PLs) can cause changes in the adjacent tissues. Infection of the maxillary posterior teeth can be easily transmitted to the maxillary sinus and cause changes in the maxillary sinus mucosa. Cone-beam computed tomography (CBCT) has high accuracy and sensitivity for detection of odontogenic lesions and is efficient for maxillary sinus assessment. PURPOSE: This study aimed to assess the maxillary sinuses for abnormalities such as mucosal thickening, polyps, and periostitis, and evaluate the periapical status of maxillary posterior teeth considering the presence of PLs, their size and distance from the sinus floor by evaluating CBCT images. MATERIALS AND METHOD: This retrospective, cross-sectional study evaluated the CBCT scans of 143 patients, depicting the posterior maxilla with at least one premolar or molar tooth present in this region. Sinus abnormalities (mucosal thickening, sinus polyps, and periostitis) and presence/ absence of PLs, its size, and its distance from the sinus floor were all assessed on CBCT scans. Data were analyzed using the Chi-square test in SPSS version 21 (a= 0.05). RESULTS: PLs were observed in 31.2% of the cases. In presence of PLs, mucosal thickening was noted in 56.8%, sinus polyps in 29.6% and periostitis in 1.3% of the maxillary sinuses. All teeth with a CBCT periapical index (CBCTPAI) score of 5 were associated with sinus abnormalities; there was neither correlation between the sizes of lesions, nor their distance from the sinus floor with sinus abnormalities (p> 0.05). CONCLUSION: PLs in the posterior maxilla have a direct correlation with the maxillary sinus abnormalities. However, the size or distance of PLs from the sinus floor had no significant effect on the frequency of sinus abnormalities.

Diagnosis of latent tuberculosis infection among pediatric household contacts of Iranian tuberculosis cases using tuberculin skin test, IFN- γ release assay and IFN-γ-induced protein-10.

BACKGROUND: Although the World Health Organization has recommended the diagnosis and prophylactic treatment of latent tuberculous infection (LTBI) in child household contacts of tuberculosis (TB) cases, the national programs in high-burden TB regions rarely implement adequate screening of this high-risk group, mainly because of resource limitations. We aimed to evaluate the prevalence of LTBI among pediatric household contacts of TB cases in two high-burden provinces in Iran. METHODS: We conducted a cohort study in children who had been in household contact with a TB index. All subjects were assessed for active TB disease. For LTBI diagnosis, tuberculin skin test (TST) and QuantiFERON®-TB Gold Plus (QFT-Plus) were performed at the time of the index TB case diagnosis, as well as, 3, 12, and 18 months, if the first results were negative. In addition, interferon-γ-induced protein-10(IP-10) concentrations were measured for all participants. RESULTS: A total of 230 children were enrolled, who had contact with an index TB case. Three contacts were diagnosed with active TB. According to the TST/QFT-Plus results, 104 (45.2%) children were identified with LTBI during our study. Significantly increased IP-10 levels were found in LTBI patients compared to healthy contacts. Accordingly, more than 50% of LTBI contacts and about 10% of healthy contacts were considered as IP-10-positive. CONCLUSION: This study alarmingly illustrates a high prevalence of LTBI among Iranian children exposed to TB cases. We, therefore, emphasize that the children living in close contact with an infectious TB case should be screened effectively and receive prophylactic therapy.

Applicability of cone beam computed tomography gray values for estimation of primary stability of dental implants / Aplicabilidade dos valores de cinza da tomografia computadorizada de feixe cônico na estimativa da estabilidade primária de implantes dentários

Objetivo: Avaliar a relação entre a densidade óssea medida em imagens de tomografia computadorizada (TC) e tomografia computadorizada de feixe cônico (TCFC) e relacionar com a estabilidade primária de implantes dentários. Material e métodos: Foram utilizadas neste estudo 20 cabeças femorais bovinas frescas, preparadas pela remoção de partes moles, secção do osso e colocação de marcadores para localização e angulação dos implantes. A densidade óssea da área peri-implantar foi determinada no pré-operatório em imagens TC e TCFC das amostras de osso peparado, representadas por unidades Hounsfield (HUs) e valores de cinza (GVs), respectivamente. Em seguida, 60 implantes em três tamanhos (diâmetro = 4 mm, comprimento = 8, 10 e 12 mm) foram inseridos nos ossos e o torque máximo de inserção (TI) foi registrado. O dispositivo Osstell também foi usado para determinar o quociente de estabilidade do implante (ISQ) para cada implante. A análise estatística foi realizada nos dados (α = 0,05). Resultados: Os valores médios ± DP de GV,HU e ISQ foram 1592,75 ± 231,82, 675,26 ± 115,38 e 61,90 ± 10,14, respectivamente. Além disso, o limite de TI mais frequente foi 30-35 Ncm (41,4%). Relações significativas foram observadas entre HU e IT, GV e IT, HU e ISQ, GV e ISQ, e IT e ISQ em todos os tamanhos de implante. Os GV e HU também se correlacionaram significativamente. Conclusão: Os valores da densidade óssea em imagens de TCFC e TC mostram-se positivamente associados para estabilidade primária de implantes dentários. Portanto, os GVs obtidos no Sistema de TCFC (Sirona's Galileos) poderiam ser usados para a seleção pré-operatória de sítios edêntulos que permitam uma melhor estabilidade do implante ou locais que requerem procedimentos adicionais para aumentar a taxa de sucesso dos implantes dentários. (AU)

Objective: To evaluate the relationship between bone density measured by computed tomography (CT) and cone beam computed tomography (CBCT) (Sirona's Galileos scanner) with primary stability of dental implants. Material and methods: 20 fresh bovine femoral heads were prepared by removal of soft tissue, sectioning of the bone, and placement of markers for location and angulation of implants. Bone density of peri-implant areas was determined preoperatively by CT and CBCT scanning of the prepared bone samples represented by Hounsfield units (HUs) and gray values (GVs), respectively. Then, 60 implants in three sizes (diameter = 4 mm, length = 8, 10, and 12 mm) were inserted into the bones and maximum insertion torque (IT) was recorded. Osstell device was also used for determining the implant stability quotient (ISQ) for each implant. Statistical analysis was performed on the data (α = 0.05). Results: Mean ± SD values of GV,HU, and ISQ were 1592.75 ± 231.82, 675.26 ± 115.38 and 61.90 ± 10.14, respectively. Moreover, the most frequent IT limit was 30-35 Ncm (41.4%). Significant relationships were observed between HU and IT, GV and IT, HU and ISQ, GV and ISQ, and IT and ISQ in all implant sizes. Moreover, GV and HU also significantly correlated to each other. Conclusion: Bone density values in CBCT and CT scans are positively associated to primary stability of dental implants. Therefore, GVs obtained from Galileos CBCT scanner can be used for preoperative selection of edentulous sites which allow for better implant stability or locations which require further procedures for enhancing the success rate of dental implants (AU)

Accuracy of digital image enhancement in detection of vertical and horizontal root fracture.

BACKGROUND: Two-dimensional intraoral radiography is the most common tool for recognizing root fractures. Improving the quality of images by means of enhancement tools can increase the recognition power of them. The aim of this study is to evaluate the effect of digital image enhancement on vertical and horizontal root fractures (HRFs) diagnostic accuracy. MATERIALS AND METHODS: In this in vitro study, 100 human extracted teeth, involving 50 mandibular premolars and 50 maxillary incisors, were investigated. In total, 25 premolar teeth were vertically fractured and other 25 sound teeth served as testing group. According to the verified methods, 25 incisor teeth were fractured and other 25 teeth of this group served as testing ones. Following, by using the charge-coupled device sensor, preapical digital images were recorded. The original images were altered using reverse-contrast and colorization enhancement tools. Two different observers independently investigated all of the images. Receiver operating characteristic analysis was used to calculate the area under the curve (AUC) and sensitivity and specificity of all images. Data analyzde using receiver operating characteristic (ROC) analysis. Two-ways variance analysis was used to assess differences in the values (P = 0.05 ). RESULTS: AUC and sensitivity and specificity related to the original, reverse-contrast, and colorized images were calculated (0.84, 0.64, 0.99), (0.84, 0.64, 0.96), and (0.82, 0.64, 0.92) respectively, for vertically root fractured images. AUC and sensitivity and specificity related to the original, reverse-contrast, and colorized images were calculated (0.49, 0.44, 0.56), (0.50, 0.44, 0.60), and (0.48, 0.48, 0.48), respectively, for horizontally root-fractured images. CONCLUSION: The results of the present study revealed that reverse-contrast and colorized enhancement filters cannot be used as critical methods in detecting in vitro vertical and HRF.

Comparison of autogenous bone graft and tissue-engineered bone graft in alveolar cleft defects in canine animal models using digital radiography.

BACKGROUND: Autogenous bone graft is the gold standard for repair of bone defects. However, osteoprogenitor stem cells are suggested as an alternative treatment. Aims: To quantitatively compare bone formation in autogenous bone graft and tissue-engineered graft using digital radiography densitometry software in canine alveolar cleft model. SETTING AND DESIGN: This experimental study on animal models was conducted in Isfahan University of Medical Sciences. METHODS: Mesenchymal stem cells (MSCs) were obtained from subcutaneous adipose tissue of 4 dogs. Undifferentiated cells were incubated with a hydroxyapatite/beta-tricalcium phosphate scaffold in an osteogenic medium for 21 days. A maxillary defect simulating human alveolar cleft was created from the alveolar crest to nasal floor with 15 mm width bilaterally. Two months later, the defect was filled with autogenous bone graft harvested from tibia on one side and tissue-engineered graft from MSCs on the other side. Digital radiography was performed on days 15, 30, 45, 60, 75, and 90 after grafting. Radiographic density was calculated by the mean numeric value of pixels of the desired area ranging from 0 (darkest) to 255 (lightest) by associated software. STATISTICAL ANALYSIS USED: The data were analyzed by Statistical Package for the Social Sciences using descriptive statistics and two-way repeated-measure analysis of variance test (α = 0.05). RESULTS: Mean density measured for autogenous bone graft group was 110.72, 82.70, 75.76, 93.57, 100.22, and 100.32 in days 15, 30, 45, 60, 75, 90, respectively and 120.7, 87.62, 83.72, 92.02, 92.30, and 93.77 in stem cell group. Although the time lapse was a significant factor in two groups (P = 0.01), the results indicated that the difference between two groups was not statistically significant (P = 0.942). CONCLUSION: Tissue-engineering can be used as an alternative method in reconstruction of bony defects with predictable clinical outcomes.

Total delay and associated factors in pulmonary tuberculosis patients in Golestan province.

BACKGROUND: Delay in diagnosis and treatment of TB is a critical component in TB control program which thereby spreading illness in the community. Sicnce Golestan province has the high risk with high rates of tuberculosis in the country, therefore, the analysis of the factors associated with treatment delay in this province for effective interventions and proper planning is considered necessary. METHODS: 689 patients documents of TB cases in the health department of Golestan University of Medical Sciences in 2016 were enrolled in this survey. The response variable in this study was having the delay or not (via determining the 34 day as cut-off point in the interval between the date of onset of the symptoms and the date of treatment start-up). The data were analyzed using SPSS 24 software and final significant level for multivariate logistic regression model was considered 0.05. RESULTS: Median (mean) treatment delay was calculated 49(77.75) days. In the current study 60.4% of patients had total delay greater than 34 days. In final model variables such as type of PTB (OR=0.645), contact history (patients who had no contact with TB patients (OR=1.441)) and patients who their contact history were unknown (OR=1.654)) had significant relationship with delay in starting treatment after 34 days of onset of symptoms of PTB patients in Golestan (p<0.05). CONCLUSION: It should beam emphasis on increasing the community's awareness of the symptoms of tuberculosis and effective collaboration should be made between the Infectious Disease Control Center and the private and public sectors.

The efficacy of metal artifact reduction (MAR) algorithm in cone-beam computed tomography on the diagnostic accuracy of fenestration and dehiscence around dental implants.

BACKGROUND: The aim of the present study was to investigate the impact of metal artifact reduction (MAR) algorithm of cone-beam computed tomography (CBCT) on the diagnostic accuracy of fenestration and dehiscence around dental implants. METHODS: Twenty-three dental implants were placed adjacent to the dehiscence and 23 adjacent to the fenestration defects on bovine bone blocks. The blocks were scanned with CBCT unit in two modes, with and without MAR algorithm. The area under the receiver operator characteristic (ROC) curves (Az value), specificity, sensitivity, positive predictive value, negative predictive value, and accuracy were determined for all modes. RESULTS: For both defects, the Az values were higher in off MAR condition. The values of sensitivity, positive predictive value, negative predictive value, and accuracy, were higher in off MAR condition for both defects. However, the specificity in both defects in the two modes was equal. CONCLUSION: The MAR algorithm in CBCT unit may not be helpful in increasing the diagnostic accuracy of fenestration and dehiscence around dental implants.

Cone-beam Computed Tomographic Analysis of Canal Transportation and Centering Ability of Single-file Systems.

INTRODUCTION: The purpose of this study was to compare canal transportation and the centering ability of Reciproc (VDW, Munich, Germany), WaveOne (Dentsply Maillefer, Ballaigues, Switzerland), and EdgeFile (EdgeEndo, Albuquerque, NM) rotary systems using cone-beam computed tomographic imaging. METHODS: Ninety mesiobuccal mandibular first molar uncalcified canals with at least a 19-mm length, a canal curvature of 15°-30° (the Schneider method), and a mature apex were selected. Canals were randomly divided into 3 groups of 30 teeth, and canal preparation with the Reciproc, WaveOne, and EdgeFile systems was performed according to the manufacturers' instructions. Cone-beam computed tomographic images were taken before and after instrumentation in the same position. Apical transportation was calculated in the distances of 2, 3, and 4 mm from the apex. Kruskal-Wallis and Mann-Whitney U tests were used to statistically analyze the data. RESULTS: The mean canal transportation was significantly lower with EdgeFile (P < .001) followed by the WaveOne rotary system. Moreover, the centering ability of the EdgeFile system was higher than that of the WaveOne and Reciproc systems. CONCLUSIONS: The EdgeFile rotary system showed the lowest transportation in both the mesiodistal and buccolingual directions and the highest centering ability. The Reciproc system showed the highest transportation and the lowest centering ability.

Detection of Vertical Root Fractures Using Cone-Beam Computed Tomography in the Presence and Absence of Gutta-Percha.

BACKGROUND: Vertical root fractures (VRFs) can significantly reduce dental prognosis. Cone-beam computed tomography (CBCT) offers better visualization of VRF than conventional radiography. However, gutta-percha creates artifacts in cone-beam CT (CBCT) images and reduces the diagnosis quality. The purpose of this study was to evaluate the accuracy of CBCT in detection of VRF in presence and absence of gutta-percha in canals. MATERIALS AND METHODS: In this cross-sectional study, 50 extracted mandibular premolars were selected. After preparing the access cavity, canals were instrumented using step-back method, and gutta-percha #40 was placed afterwards. The fractures were created using electromechanical universal testing machine on 25 teeth. The teeth were randomly placed in dry mandibular dental sockets, and the first CBCTs were taken. Then the gutta-percha was removed, and the second CBCTs were taken. RESULTS: The results of Kappa coefficient between two observers in roots with and without gutta-percha were 0.644 and 0.830, respectively (p value ≤ 0.001). The sensitivity and specificity of VRF diagnosis in assessing gutta-percha filled canals were 32% and 68% for the first observer, respectively (Kappa < 0.000, p value = 1.000), and 40% and 68% for the second observer, respectively (Kappa = 0.080, p value = 0.556). The sensitivity and specificity of VRF diagnosis in assessing the empty canals (without gutta-percha) were 72% and 96% for the first observer, respectively (Kappa = 0.680, p value ≤ 0/001), and 72% and 96% for the second observer, respectively (Kappa = 0.680, p value ≤ 0/001). CONCLUSION: The intracanal filling materials such as gutta-percha reduce the diagnostic ability of vertical root fractures. Hence, it is recommended to remove those materials from root canals before imaging to improve the diagnostic potential of CBCT.

Assessment of palatal rugae pattern for sex and ethnicity identification in an iranian population.

BACKGROUND: Palatal rugoscopy is a reliable method in the forensic personal identification and racial group specification. the aim of the present study is to use palatal rugae pattern in sex and ethnicity identification applications. MATERIALS AND METHODS: Four hundred individual dental casts from four different ethnic populations of Iran were randomly selected. The pattern of the palatal rugae (shape, length, and number) investigated and its reliability to classify sex and minor ethnicity for each individual cast was evaluated. (P < 0.05) considered significant. RESULTS: The most common rugae shapes were straight, followed by wavy and curved types. The least frequent shapes were converging and circular types. Palatal rugae patterns were unique to each person. However, they could not differentiate males and females and had low abilities to classify the racial subsets. CONCLUSION: The palatal rugae pattern was unique to each individual and palatal rugoscopy can be considered as a reliable forensic identification tool where utilizing other methods such as DNA profiling, fingerprint, and dental record comparison is impossible or difficult. In this study, palatal rugoscopy was not a reliable method to classify the sex of an individual and to differentiate between different racial subsets.

Bilateral coronoid hyperplasia causing painless limitation of mandibular movement.

The coronoid process is a beaklike process in the ramus of the mandible. Coronoid process hyperplasia (CPH) is a rare possible cause of reduced mouth opening. An overgrown process interferes with mandibular rotation and lateral excursion and hence leads to restricted mouth opening (RMO). Although some factors are suggested, etiology of CPH is not completely known. Prescription of suitable radiography is necessary for an accurate diagnosis. This article reports a 30-year-old man with bilateral CPH and progressive RMO since childhood. This disorder affected his oral hygiene and quality of life. With the help of different types of radiography, CPH was diagnosed and coronoidectomy was the only treatment option. The patient showed normal jaw movements after the surgery and postoperative physiotherapy. General dentists have an important role in noticing RMO and referring the patients to maxillofacial radiologists. Although it is a rare phenomenon, general dentists need to keep CPH in mind as a possible cause. Panoramic imaging accompanied by computed tomography or cone beam computed tomography is the best imaging option in such cases.

Biometric Analysis of C-shaped Root Canals in Mandibular Second Molars Using Cone-Beam Computed Tomography.

Introduction: The configuration of C-shaped root canals, root canal wall thickness and orientation of the thinnest area using CBCT in mandibular second molars were assessed. Methods and Materials: Seventy five CBCT scans were evaluated. Axial sections were evaluated to determine the configuration of C-shaped canals in the coronal, middle and apical regions. The root canal path from the orifice to the apex, the thinnest root canal wall and its orientation were all determined. Data were analyzed using one-way ANOVA and post hoc Tukey's test. Results: The most common configurations were Melton's type I in the coronal and middle and types I and IV in the apical region. The mean thicknesses of the thinnest root canal wall were 1.94±0.43, 1.42±0.57 and 1.10±0.52 mm in the coronal, middle and apical regions, respectively. The lingual wall was the thinnest wall in the coronal, middle and apical regions and it was thinner in the apical than in the middle and coronal regions. The lingual wall was thinner in the middle third of the mesial root compared to the distal root (P<0.05). Conclusion: The lingual wall was the thinnest in C-shaped root canals of mandibular second molars of an Iranian population. Type, number and pathway of canals may vary from the orifice to the apex.

Assessment of the anterior loop of mental nerve in an Iranian population using cone beam computed tomography scan.

BACKGROUND: The anterior loop is an important structure in the interforaminal area of the mandible. The aim of the present study was to assess the prevalence and length of the anterior loop of mental nerve using cone beam computed tomography (CBCT) scan and to compare the differences between age, gender, and side. MATERIALS AND METHODS: A total of 180 projections were analyzed in different sectional planes. The inferior alveolar nerve was determined. To measure the length of anterior loop in tangential plane, two parallel lines from the anterior point of mental foramen and anterior point of anterior loop were drawn. The distance between these two lines was measured by drawing a perpendicular line on them. The data were analyzed by SPSS (version 22). McNemar's test, Chi-square test, and t-test were performed to compare the significance of findings regarding side, age, and gender. P < 0.05 was considered statistically significant. RESULTS: The results showed that 32.8% of images had anterior loop. The mean lengths of anterior loop in the right and left sides were 2.69 mm (standard deviation [SD] = 1.56) and 2.36 mm (SD = 1.16), respectively. There were no statistically significant differences between the mean lengths of the anterior loop in both sides (P = 0.18). CONCLUSION: Great care is required when placing implants in proximity to mental foramen to avoid anterior loop injury. Because of the variations of anterior loop length in each patient, a fixed distance anterior to the mental foramen is not safe, and the anterior loop length should be determined for each individual. The use of CBCT provides accurate measurements of the length of anterior loop.

Posttraumatic Mandibular Asymmetry Presenting in a Young Adult.

One of the most common sites of injury of the facial skeleton is mandibular condyle. However, it is the least diagnosed site of trauma in the head and neck regions. A trauma to the mandible and specifically condylar zone during childhood, may lead to asymmetry or mandibular bilateral distortion, which is usually manifested in the second decade of life when the etiology is unknown to most people. This report is about an adult male complaining about facial asymmetry with an unknown source. Obvious clicking at the right side and shorter right ramus and condyle's head deviation directed us to a childhood trauma and fracture.

CBCT Assessment of Mental Foramen Position Relative to Anatomical Landmarks.

Purpose. This study was carried out on an Iranian population aiming to investigate mental foramen position relative to inferior border of mandible and skeletal midline and its gender and age differences on CBCT projections. Materials and Methods. A number of 180 CBCT images of patients were analyzed in different planes (tangential, cross-sectional, and axial). The distances from the superior border of mental foramen to the inferior border of mandible and from the anterior border of mental foramen to the midline were calculated. Results. The mean distance from mental foramen to the inferior border of mandible in the right side was 13.26 mm (SD ± 2.34) and in the left side was 13.37 mm (SD ± 2.19). There was a statistically significant difference between genders in terms of the distance between mental foramen and inferior border of mandible (P value = 0.000). The mean distances from mental foramen to midline were 25.86 mm (SD ± 0.27) and 25.53 mm (SD ± 0.31) in the right and left sides, respectively. Conclusions. The vertical and horizontal positions of mental foramen can be determined from stable anatomical landmarks such as mandibular inferior border and skeletal midline in both dentulous and edentulous patients. The distance from the superior border of mental foramen to the inferior border of mandible exhibited sexual dimorphism.

Cone-Beam Computed Tomography Evaluation of Mental Foramen Variations: A Preliminary Study.

Background. Mental foramen is important in surgical operations of premolars because it transfers the mental nerves and vessels. This study evaluated the variations of mental foramen by cone-beam computed tomography among a selected Iranian population. Materials and Methods. A total number of 180 cone-beam computed tomography projections were analyzed in terms of shape, size, direction, and horizontal and vertical positions of mental foramen in the right and left sides. Results. The most common shape was oval, opening direction was posterior-superior, horizontal position was in line with second premolar, and vertical position was apical to the adjacent dental root. The mean of foremen diameter was 3.59 mm. Conclusion. In addition to the most common types of mental foramen, other variations exist, too. Hence, it reflects the significance of preoperative radiographic examinations, especially 3-dimensional images to prevent nerve damage.

Accuracy and reliability of linear measurements using tangential projection and cone beam computed tomography.

BACKGROUND: Providing a cross-sectional image is essential for preimplant assessments. Computed tomography (CT) and cone beam CT (CBCT) images are very expensive and provide high radiation dose. Tangential projection is a very simple, available, and low-dose technique that can be used in the anterior portion of mandible. The purpose of this study was to evaluate the accuracy of tangential projection in preimplant measurements in comparison to CBCT. MATERIALS AND METHODS: Three dry edentulous human mandibles were examined in five points at intercanine region using tangential projection and CBCT. The height and width of the ridge were measured twice by two observers. The mandibles were then cut, and real measurements were obtained. The agreement between real measures and measurements obtained by either technique, and inter- and intra-observer reliability were tested. RESULTS: The measurement error was less than 0.12 for tangential technique and 0.06 for CBCT. The agreement between the real measures and measurements from radiographs were higher than 0.87. Tangential projection slightly overestimated the distances, while there was a slight underestimation in CBCT results. CONCLUSION: Considering the low cost, low radiation dose, simplicity and availability, tangenital projection would be adequate for preimplant assessment in edentulous patients when limited numbers of implants are required in the anterior mandible.

Aplasia and hypoplasia of the maxillary sinus: A case series.

Maxillary sinus aplasia and hypoplasia are rare conditions that can cause symptoms such as headaches and voice alteration. The majority of patients are asymptomatic, but these conditions must be noticed for importance of differential diagnosis such as infection and neoplasms. Conventional radiographs could not differentiate between inflammatory mucosal thickening, neoplasm, and hypoplasia of the sinus. Computed tomography (CT) and also cone beam computed tomography (CBCT) are the proper modalities to detect these conditions. In the present study, CBCT findings of three cases with maxillary sinus hypoplasia and aplasia are reported.