Cone beam CT study of temporal crest canal

Statement of the Problem: It is crucial for clinicians to be certain about the location of mandibular canal and determine any anatomical variants relevant to it. The temporal crest canal [TCC] is a rare anatomical variant of mandibular canal that lack of awareness about its presence can complicate surgical procedures

Purpose: This study investigated the anatomical characteristics and prevalence of the TCC using CBCT

Materials and Method: This descriptive cross-section study evaluated 327 CBCTs [654 sides] from all the patients with various problems. TCC on sagittal and axial plans were identified and then classified into two types based on their configuration. The prevalence of TCC was calculated amongst men and women

Results: Six TCC [0.91%] were observed in 654 sides. We observed all 6 TCCs in females. One case [0.30%] was bilateral TCC, and the remaining four [1.22%] cases were unilateral TCC [two on the left and two on the right side]. Considering the classification of TCC, five sides had presentation of type I and one case was type II based on Kawai et al. study

Conclusion: Three-dimensional images of CBCT data are useful in confirming the presence of TCC. TCC is considered as a clinically significant structure; therefore, this variation should be carefully investigated using reconstructed CBCT images

Comparison of dental panoramic radiography and CBCT for measuring vertical bone height in different horizontal locations of posterior mandibular alveolar process

Statement of the Problem: Accurate measurement of the available bone height is an essential step in the pre-surgical phase of dental implantation. Panoramic radiography is a unique technique in the pre-surgical phase of dental implantations because of its low cost, relatively low-dose, and availability

Purpose: This article aimed to assess the reliability of dental panoramic radiographs in the accurate measurement of the vertical bone height with respect to the horizontal location of the alveolar crest

Materials and Method: 132 cone-beam computed tomography [CBCT] of the edentulous mandibular molar area and dental panoramic radiograph of 508 patients were selected. Exclusion criteria were bone abnormalities and detectable ideal information on each modality. The alveolar ridge morphology was categorized into 7 types according to the relative horizontal location of the alveolar crest to the mandibular canal based on CBCT findings. The available bone height [ABH] was defined as the distance between the upper border of the mandibular canal and alveolar crest. One oral radiologist and one oral surgeon measured the available bone height twice on each modality with a 7-dayinterval

Results: We found a significant correlation between dental panoramic radiographs and cone-beam computed tomography values [ICC=0.992, p< 0.001]. A positive correlation between the horizontal distance of the alveolar crest to the mandibular canal and measured differences between two radiographic modalities had been found [r=0.755, p< 0.001]. For each single unit of increase in the horizontal distance of the alveolar crest to the mandibular canal, dental panoramic radiographs showed 0.87 unit of overestimation [p< 0.001]

Conclusion: Dental panoramic radiographs can be employed safely in the pre-surgical phase of dental implantation in posterior alveolus of mandible, especially in routine and simple cases

Comparison of the bony changes of TMJ in patients with and without TMD complaints using CBCT

Statement of the Problem: Temporomandibular joint disorders [TMD] may show a poor correlation between their clinical findings and radiological characteristics

Purpose: The aim of this study was to assess the osseous alterations of temporomandibular joint [TMJ] in symptomatic and asymptomatic subjects by employing cone beam computed tomography [CBCT] images

Materials and Method: In this study, CBCT images of 120 temporomandibular joints in 30 patients with TMJ disorder and 30 age- and sex-matched individuals without TMJ complaints were evaluated. Osteoarticular derangements of the joint were assessed by two experienced examiners. Data was statistically analyzed with SPSS software using chi-square test [p <0.05]

Results: Out of 120 CBCT images [60 in each group], at least one osseous change was observed in 90% and 86.7% joints in symptomatic and asymptomatic subjects, respectively. There were no significant differences between symptomatic and asymptomatic subjects regarding frequency of osteoarticular changes including flattening [73.3% vs. 75%], irregularity [36.7% vs. 48.3%], sclerosis [20% vs. 8.3%], cyst [3.3% vs. 3.3%], erosion [13.3% vs. 21.7%], hypoplasia [3.3% vs. 5%], ankylosis [1.7% vs. Zero], osteophyte [43.3% vs. 40%], decrease joint space [3.3% vs. 3.3%], and increase joint space [5% vs. 5%]. [p> 0.05]

Conclusion: By employing CBCT as a modern diagnostic imaging tool, findings of this study revealed that the frequency of various temporomandibular joint alterations on CBCT images is comparable in patients with and without TMD complaints, suggesting that some people with TMJ structural damage may not display clinical manifestations. Moreover, CBCT imaging might not be necessary for TMD patients and more attention should be given to clinical examination

Influence of head position on the cbct accuracy in assessment of the proximity of the root apices to the inferior alveolar canal

Statement of the Problem: The most important risk factor for inferior alveolar nerve [IAN] damage is the proximity of the mandibular root apices to the alveolar canal. Failure to position the patient's head at standardized orientation during cone beam computed tomography [CBCT] scans might adversely affect the relative position of the alveolar canal and mandibular root apices with subsequent treatment failure

Purpose: The purpose of the present study was to investigate the influence of the orientations of the skull during the scanning procedure on the accuracy of CBCT images in determining the positional relationship of the mandibular tooth apices to the alveolar canal

Materials and Method: CBCT scans of 7 human dry skulls were obtained by using NewTom VGi CBCT in standard, tilt, flexion, extension and rotation positions of the head. The shortest radiographic distance between the mandibular tooth apices and the IAN canal of 20 points were measured on cross sectional images of CBCT in all position scans. A sample t-test was used to compare the measurements at different head position with the standard position values

Results: Significant differences were found in the measurements of normal and tilt orientations. However, there was no statistically significant difference between the measurements in standard position and other deviated positions. The mean errors in all head positions were less than 0.5mm

Conclusion: Alteration of patient head positioning during CBCT scanning does not affect the relative position of the IAN and the apices of posterior teeth

Comparison of the effects of transcutaneous electrical nerve stimulation and low-level laser therapy on drug-resistant temporomandibular disorders

Statement of the Problem: Temporomandibular disorder [TMD] is a clinical term used for clinical signs and symptoms that affect the temporomandibular joints, masticatory muscles, and associated structures. Surgical and non-surgical treatments can be used for management of TMD. Non-surgical route is the main part of the treatment, since clinicians prefer non-aggressive treatment for TMD such as pharmacological and physical therapy. Low-level laser therapy [LLLT] and transcutaneous electrical nerve stimulation [TENS] are the main procedures in physical therapy

Purpose: The aim of this study was to evaluate the effectiveness of TENS and LLLT in treatment of TMD patients who did not respond to pharmacological therapy

Materials and Method: This clinical trial was performed on 45 patients who randomly received either TENS or LLLT for 8 sessions. LLLT was applied with diode laser [Ga-Al-As, 980nm, dose 5micro/cm[2]] and TENS by using two carbon electrodes with 75 Hz frequency [0.75 msec pulse width]

Helkimo index and visual analogue scale [VAS] were measured during the treatment period and throughout the follow-up sessions

Results: Significant reduction in the VAS and Helkimo index was observed in both TENS and LLLT group. There was no significant difference between the two methods during the treatment; however, TENS was more effective in pain reduction in follow-ups

Conclusion: This study justified the use of TENS therapy as well as LLLT in drug-resistant TMD. Both were useful in relieving the pain and muscles tenderness, although, TENS was more effective than LLLT

Is mandibular fossa morphology and articular eminence inclination associated with temporomandibular dysfunction?

Statement of the Problem: Finding a significant relationship between temporomandibular joint [TMJ] morphology and the incidence of temporomandibular dysfunction [TMD] may help early prediction and prevention of these problems

Purpose: The purpose of the present study was to determine the morphology of mandibular fossa and the articular eminence inclination in patients with TMD and in control group using cone beam computed tomography [CBCT]

Materials and Method: The CBCT data of bilateral TMJs of 40 patients with TMD and 23 symptom-free cases were evaluated. The articular eminence inclination, as well as the glenoid fossa depth and width of the mandibular fossa were measured. The paired t-test was used to compare these values between two groups

Results: The articular eminence inclination and glenoid fossa width and depth were significantly higher in patients with TMD than in the control group [p < 0.05]

Conclusion: The articular eminence inclination was steeper in patients with TMD than in the control group. Glenoid fossa width and depth were higher in patients with TMD than that in the control group. This information may shed light on the relationship between TMJ morphology and the incidence of TMD

Comparison of the pharyngeal airway volume between non-syndromic unilateral cleft palate and normal individuals using cone beam computed tomography

Statement of the Problem: Individuals with cleft lip and cleft palate mostly have airway problems. Introduction of cone beam computed tomography [CBCT] and imaging software has provided the opportunity for a more precisely evaluating 3D volume of the airway

Purpose: The purpose of this study was to analyze and compare 3D the pharyngeal airway volumes of cleft palate patients with normal individuals using CBCT

Materials and Method: 30 complete cleft palate patients were selected from the Department of Orthodontics; Dental University [Shiraz, Iran] who had CBCT scans of the head. The control group included 30 individuals with Class I angle occlusion who were matched for age and gender with the experimental group. ITK-SNAP 2.4.0 PC software was used to build 3D models of the airways for the subjects and measuring airway volumes. The statistical analyses were performed using SPSS software [version 19]. Mann-Whitney test was adopted with p< 0.05 as statistical significance

Results: The average volume of the pharyngeal airway of cleft group was 18.6 cm3, with mean volumes of 6.8 cm3 for the superior component and 11.3 cm3 for the inferior component. The total and superior airway volume of cleft group were significantly lower than non-cleft groups [p= 0.008, p= 0.00, respectively] but the inferior airway volumes were not significantly different between the cleft and non-cleft groups. There was a significant and positive correlation between superior airway volume and inferior airway volume in cleft palate patients [r=+0.786, p< 0.001] and control group [r=+0.575, p= 0.001]

Conclusion: 3D analysis showed that the nasal and total airway was restricted in individuals with cleft palate but the inferior airway was not compromised in these individuals. This would be a crucial data to be considered for surgeons during surgical planning

Evaluation of condylar position after orthognathic surgery for treatment of class ii vertical maxillary excess and mandibular deficiency by using cone-beam computed tomography

Statement of the Problem: In orthognathic surgeries, proper condylar position is one of the most important factors in postoperative stability. Knowing the condylar movement after orthognathic surgery can help preventing postoperative instabilities

Purpose: The aim of this study was to evaluate the condylar positional changes after Le Fort I maxillary superior repositioning along with mandibular advancement by using cone beam computed tomography [CBCT]

Materials and Method: This cross-sectional study was conducted on 22 subjects who had class II skeletal malocclusion along with vertical maxillary excess. Subjects underwent maxillary superior repositioning [Le Fort I osteotomy] along with mandibular advancement. The CBCT images were taken a couple of days before the surgery [T0], and one month [T1] and 9 months [T2] after the surgery. The condyles positions were determined from the most superior point of the condyle to three distances including the deepest point of the glenoid fossa, the most anteriorinferior point of the articular eminence, and the most superior point of the external auditory meatus in the sagittal plane

Results: The mean mandibular advancement was 4.33 +/- 2.1 mm and the mean maxillary superior repositioning was 4.66 +/- 0.3 mm. The condyles displaced inferiorly, anteriorly, and laterally between T0 and T1. They were repositioned approximately in the initial position in T2. No correlation was observed between the mandibular and maxillary movement and the condylar positions

Conclusion: The condyles displaced in the inferior-anterior-lateral position one month after the bilateral sagittal split osteotomy for mandibular advancement in combination with the maxillary Le Fort I superior repositioning. It seems that the condyles adapted approximately in their initial position nine months after the surgeries

Relationship of elongated styloid process in digital panoramic radiography with carotid intima thickness and carotid atheroma in doppler ultrasonography in osteoporotic females

Statement of the Problem: Cardiovascular disease and osteoporosis are major health dilemmas. Osteoporotic patients frequently display vascular calcification that consequently increases the cardiovascular morbidity and mortality

Purpose: This study aimed to investigate the relation of osteoporosis, vascular calcification [atheroma, intima-media thickness [IMT]] and elongated styloid process [ESP] in a sample of osteoporotic and normal female individuals

Materials and Method: This study recruited 78 women who were assessed for bone mass density [BMD]. Sample included individuals with normal BMD [n=13, 17%], osteopenia [n=36, 46%], and osteoporosis [n=29, 37%]. The presence of atheroma and IMT was examined using color Doppler ultrasonography [CD-US]. In addition, digital panoramic radiographs [PRs] were obtained to assess ESP

Results: In this study, 55 subjects [70%] with low BMD exhibited at least one side ESP. Femoral BMD decreased significantly in subjects with ESP [p= 0.03]. Bilateral ESP was correlated with the presence of atheroma [p= 0.029]. The CIMT was greater in patients with ESP, although the relation was not significant

Conclusion: The obtained data suggest referring the aged individuals with ESP for BMD assessment and individuals with low bone mass and ESP for more cardiovascular risk assessment

feasibility of ultrasonography in defining the size of jaw osseous lesions

Statement of the Problem: Jaw bone lesions are common pathologic conditions. The role of ultrasonography in evaluation of the extra-osseous lesions is confirmed, however, this imaging modality is not the diagnostic routine for the intraosseous jaw lesions

Purpose: The purpose of this study was to evaluate the efficiency of ultrasonography in diagnosis of intra-osseous jaw lesions concerning their size and content and also to study its correlation with the histopathological findings

Materials and Method: For this study, 15 patients with intra-osseous jaw lesions in the maxilla and mandible were selected from those referred to the Department of Oral Surgery. Panoramic imaging, computed tomography [CT] or cone beam computed tomography [CBCT] and ultrasonography [USG] were performed for all the lesions. The size of the lesions was measured by USG and then compared with CT or CBCT. Moreover, the correlation amongst the echographic patterns and histopathologic results was evaluated

Results: In 12 cases, size values were in complete agreement with CT or CBCT. The size of 3 lesions could not be measured by the radiologist due to the thickness of buccal cortical plate

Conclusion: Findings of this study suggested that USG might be feasible in estimating the size of intra-osseous jaw lesions with little underestimation. This study also confirmed that ultrasound imaging was a very useful imaging technique which could provide significant diagnostic information regarding the content of jaw bone lesions where the buccal bone thickness was thin enough

Comparison of panoramic radiography with cone beam CT in predicting the relationship of the mandibular third molar roots to the alveolar canal

PURPOSE: Preoperative radiographic assessment of the mandibular third molars is essential to prevent inferior alveolar nerve damage during extraction. The purpose of this study was to assess the reliability of panoramic signs of association between the roots of teeth and the canal, and to compare the panoramic signs with cone beam computed tomography (CBCT) findings. MATERIALS AND METHODS: CBCT images of 132 impacted mandibular third molars were evaluated to determine the association of the root to the canal. The CBCT findings were compared with the corresponding panoramic images. Logistic regression analysis was used to define the diagnostic criteria of the panoramic images. RESULTS: Among the panoramic signs, loss of the cortical line was the most frequent radiographic sign predicting association (sensitivity: 79.31). Contact of the tooth with the canal was observed in all cases in which the loss of cortical line of the canal or darkening of the roots was found on the panoramic radiographs. CONCLUSION: Darkening of the roots and loss of the cortical line on panoramic radiographs might be highly suggestive of the risk of nerve injury.

Ultrasonographic findings of mesenchymal chondrosarcoma of the mandible: report of a case

Today, ultrasound imaging is being widely used to assess soft tissue lesions in the maxillofacial region. However, ultrasound investigations of intra-osseous lesions are rare, especially for tumors of the jaws. This report emphasized the capability of this useful imaging modality in identification of the characteristics of malignant conditions involving the bone. Mesenchymal chondrosarcoama, one of the unusual malignant conditions of the jaw, was presented in a young male with significant facial swelling. Different imaging modalities parallel with the histopathologic investigation confirmed the diagnosis. Interestingly, destruction of the bony cortex and new bone formation with a characteristic "sun ray appearance", highly suggestive of sarcomas, was manifested on the ultrasonograph. Thus, this report presented the ultrasonographic features of chondrosarcoma of mandible and considered the ultrasonography to be a useful imaging modality to evaluate intra-osseous jaw lesions.