Visibility Of Mandibular Canal Research Articles

Effect of CBCT dose reduction on the mandibular canal visibility: ex vivo comparative study.

To compare the difference in mandibular canal (MC) visibility using three different cone beam computed tomography (CBCT) acquisition protocols: high resolution (HR), standard resolution (ST) and Quick scan+ (QS+). Twenty-five human dry mandibles were scanned by one CBCT machine; i-CAT FLX (Imaging Sciences International, Hatfield, PA, USA), using three different acquisition protocols: high-resolution (HR), standard (ST) and Quick scan+ (QS+). DICOM data were transferred to a third party software Ondemand 3D (Cybermed Co., Seoul, Korea). The fusion module was used to superimpose images derived from different acquisition protocols to standardize the areas to compare the MC visibility. Comparison was performed at nine selected cross sections extending from an area distal to the third molar posteriorly to the first premolar anteriorly. Two expert radiologists evaluated the degree of MC visibility using five-scale scoring system. There was a statistically significant difference between the three acquisition protocols (HR, ST, QS+) at all investigated areas regardless of dentition status (p value < 0.001-0.034) except at the MR1M area where there was no statistically significant difference (p value = 0.094). HR protocol showed the highest prevalence of fully and partially corticated MCat almost all investigated areas while QS+ protocol showed the highest prevalence of invisible MC and clear and unclear non-corticated MC at almost all investigated areas. QS+ protocol of i-CAT FLX CBCT machine is a recommended low-dose CBCT acquisition protocol for MC visibility at dentulous posterior mandibular regions while ST protocol is recommended at edentulous areas.

Effect of calibration of a medical review monitor on the visibility of mandibular canal at dental implant sites: A cone beam CT study.

The aim of this study was to assess the visibility of mandibular canal (MC) on cone beam CT (CBCT) images using a medical review monitor under two different calibration modes. The effect of age, gender, and location of the dental implant site was also assessed. CBCT images of 428 dental implant sites were selected for the study. Images were displayed twice on a medical review monitor using two different calibration modes: standard and DICOM, and two observers evaluated the visibility of the MC using four-point scoring scale (1-4, poor to excellent). Cohen Kappa was used to assess intra and inter-rater reliability. Chi-square test was used to compare proportions of MC visibility by gender and location and one-way ANOVA was used to compare mean age and MC visibility. Each observer classified the visibility of MC with a total agreement of 100% between DICOM mode and standard mode (Kappa = 1, P < 0.001 for each observer). In each mode, a strong agreement (inter-rater reliability) was detected between the observers (Cohen's kappa = 0.88 for both modes, P < 0.001) with a percent agreement of 95.3% for each mode. Gender and location were not statistically associated with MC visibility (P > 0.05). Age, however, was a significant predictor of MC visibility (P < 0.05). DICOM calibration had no added value over standard calibration for assessing the visibility of MC at dental implant sites on a medical review monitor. Only the age had significant effect on the visibility.

The evaluation of mandibular canal visibility on cone beam computed tomography (CBCT) images: A cross-sectional study

The evaluation of mandibular canal visibility on cone beam computed tomography (CBCT) images: A cross-sectional study

Mandibular canal visibility using a plain volumetric interpolated breath-hold examination sequence in MRI.

To evaluate the validity of plain volumetric interpolated breath-hold examinations (VIBEs) for detecting the course of the mandibular canal, and to compare the results with contrast-enhanced (CE) VIBE images. From our imaging archives, we collected 28 cases taken with a VIBE sequence both before and after intravenous administration of gadolinium hydrate, and then two observers evaluated neurovascular bundle (NVB) visibility in the VIBE images. For the invisible NVB cases, we identified the invisible areas and analysed the causes of invisibility. For cases that also had corresponding CT thin slice images, we obtained a fusion image between MRI and CT, and investigated the relationship between the NVB in VIBE and the mandibular canal in CT images. The visibility of the NVBs in plain VIBE was 89%, the same as on CE VIBE. There were three invisible cases in each plain and CE VIBE images. The invisible areas were premolar in three cases, and molar in one case, and the causes of the invisibility were a metallic artefact in one case and motion artefacts in the other two cases. A plain VIBE can depict the NVB at the same rate as CE VIBE, and is suitable for detecting NVBs.

Comparison Between Conventional Radiography and 3D Volumetric Imaging for Location of Mandibular Canal: In Vivo Study

Aim: The aim of the study was to evaluate the visibility and location of mandibular canal in the mandibular posteriors using orthopantomography and digitalized volumetric tomography. Material and Methods: Twenty-five patients were included in the study with mandibular posterior edentulous areas, where visibility and location of mandibular canal was assessed using orthopantomography and digitalized volumetric tomography. Both parameters were assessed at the mental foramen, at 1 cm, 2 cm, and 3 cm posterior to mental foramen. Results: The results obtained showed that the mandibular canal was more clearly visible at the mental foramen at 1 cm and 2 cm posterior to the mental foramen using digitalized volumetric tomography, which was statistically significant (P = 0.000). At 3 cm posterior to the mental foramen the visibility of the mandibular canal did not differ among the techniques (P = 0.297). The location of the mandibular canal was obtained in superoinferior dimension in orthopantomography and superoinferior and buccolingual dimension was measured in digitalized volumetric tomography where the mandibular canal was located more inferiorly and lingually in mandible. Conclusion: Digitalized volumetric tomography ( DVT) is advantageous than orthopantomography (OPG) for visibility and location of mandibular canal. The precise location of the mandibular would help in planning for implant placement and other interventions in mandibular posteriors.

Descriptive study of mandibular canal visibility: morphometric and densitometric analysis for digital panoramic radiographs.

To assess the visibility of the mandibular canal (MC) morphology in different jaw dental segments (JDSs) in relation to morphometric and densitometric parameters on digital panoramic radiographs (DPRs). 32 DPRs (155 JDSs) were selected randomly after retrieval. MC visibility in conjunction with superior and inferior border visibility was scored on a 5-point scale in four places on the JDS-that is, for the medial, distal, superior and inferior MC parts. Morphometric and densitometric analyses were made horizontally and vertically in the JDS region. Descriptive statistics, Fisher's exact test, Mann-Whitney U test and additional tests were performed. There was no significant difference in MC visibility for the superior, inferior, medial and distal parts of the JDSs. Statistically significant (p < 0.05) differences were identified between particular visibility scores of the superior and inferior MC borders. In 22.0-24.7% of JDSs, the superior MC border was not visible, more than twice as often as the inferior MC border was not visible (9.1-10.2%). The visibility of superior and inferior MC borders in JDSs was not related to the morphometric or densitometric assessment parameters, or to age, gender, JDS location, condition or the visibility of neighbouring MC parts or contralateral JDSs. DPRs failed to provide MC visibility based on a single factor. Particular differences were identified between the levels of visibility of the superior and inferior MC borders. More advanced radiological investigation methods could be required for the evaluation of about 25% of JDSs when superior MC border identification is obligatory.

The visibility of mandibular canal on orthoradial and oblique CBCT slices at molar implant sites

ABSTRACTThe aim of the present study was to compare visibility of the mandibular canal on cone beam computed tomography (CBCT)-based orthoradial and oblique slices at molar implant sites. CBCT images for 132 mandibular molar implant sites were selected for the study. After generating orthoradial and oblique slices, two observers evaluated the visibility of the mandibular canal using three-point scoring scale (1–3, good to excellent). Wilcoxon signed-rank test compared the visibility scores of the two slices. Both orthoradial and oblique slices obtained from CBCT had only very good to excellent mandibular canal visibility scores. At 114 mandibular molar implant sites, the visibility score was equal on both orthoradial and oblique slices. Although the visibility score was higher on orthoradial slices for 12 implant sites, the visibility score was higher for six implant sites on oblique slices and the difference was not significant. Therefore, the visibility of the mandibular canal was excellent and comparable on most of orthoradial and oblique slices obtained from CBCT images.

Panoramic radiographic study of mandibular canal and mental foramen in a selected Iranian population

Background and Aim: The mandibular canal and mental foramen are two important anatomic landmarks that should be noted before dental surgeries in the posterior region of the mandible. The aim of this study was to evaluate the accuracy of digital panoramic images in visualizing the mandibular canal and mental foramen. The horizontal location of mental foramen among Iranians was also investigated. Materials and Methods: In this cross-sectional study, 150 digital panoramic images acquired from the radiology database at the Dental Faculty of Hamedan University of Medical Sciences were analyzed. All the panoramic radiographs were shot by a digital panoramic machine, CRANEX ® Tome Ceph (Soredex, Helsinki, Finland), considering standard exposure parameters. The visibility of mandibular canal and mental foramen and the horizontal location of mental foramen were assessed by three examiners independently. Results: The visibility of mandibular canal and mental foramen on both left and right sides was 96.6% and 79.7%, respectively. The most frequent horizontal position of mental foramen was in line with the second premolar on the right (48%) and left (51.3%) sides, followed by the area between the first and second premolar. The mean distance between two mental foramina was 49.23 mm and 46.89 mm in males and females, respectively. Conclusion: Although panoramic images showed a satisfactory accuracy in identifying mandibular canal and mental foramen, caution should be taken, especially when identifying mental foramen.

Evaluation of the mandibular canal visibility on cone-beam computed tomography images of the mandible.

The mandibular canal (MC) is an important and necessary landmark that should be considered before any surgery in the posterior region of the mandible. This study is aimed to evaluate the visibility and position of the MC in an Iranian population using cone-beam computed tomography. In this cross-sectional study, cone-beam computed tomography images of 69 patients, which were available as soft copies in the archives of the databases in the Department of Oral Radiology at Hamadan University of Medical Sciences (Hamadan, Iran), were analyzed. The visibility, corticalization, and position of the MC were assessed by 2 expert oral radiologists independently. The χ2 test, unpaired t test, and 1-way analysis of variance were used for analysis. The right and left MCs were clearly visible in 89.6% and 84.7% of the cases, respectively. Among 87.5% of cases, the MC was observed simultaneously in 2 sides. Position of the MC in relation to surrounding structures showed lowest asymmetry at the second premolar area. There were no statistically significant difference between sex and the evaluated parameters. Cone-beam computed tomography was successful in most cases in displaying the MC. The areas with most MC visibility in the right and left sides were the second and third molar regions, respectively. This visibility declined forwardly in both sides.

Detection of anatomical variations in mandible by panoramic radiography

Aim: To assess the visibility, frequency and gender variations of mandibular canal, mental foramen, anterior loop of mental nerve, incisive canal and lingual foramen in Indian population. Material and Methods: Retrospective analysis of total 300 panoramic radiographs were selected for the study. Radiographs were analysed for the mandibular canal, mental foramen, anterior loop of mental nerve, incisive canal and lingual foramen by two independent observers and scores were recorded. Intra and inter-examiner reliability was assessed by kappa-statistics percentages of observations were obtained and Chi-square test was used to find out association of age and gender with visibility of anatomical landmarks. Results: The mandibular canal was visible in 100% of the 300 cases. Anterior looping of the mental nerve was not visible in 90% (270) of the cases, with 1.3% having good visibility. The mental foramen was moderately visible in 66% cases. The lingual foramen could not be visualized in 95.3% of the cases, with poor visibility in 0.7%. An incisive canal was observed in 33% of the cases, good visibility with only 1.3%. Contingency tables with Chi-square test showed that gender does not exert any effect on the visibility of the anatomical structures in the mental interforaminal region ( P > 0.05). Chi-square test reveled, significant difference exist between age and visibility of mandibular canal ( P Conclusion: The important conclusion drawn from the present study is that as far as mandibular canal and mental foramen is concerned, panoramic images provide sufficient information. However, it is insufficient for detection of interforamina structures especially for presurgical implant planning in the mental region and may need to be supplemented with three dimensional imaging for better visualization of the area.

Visibility of mandibular canal on panoramic radiograph after bilateral sagittal split osteotomy (BSSO)

This study aimed to assess the visibility of the mandibular canal (MC) on panoramic radiographs after bilateral sagittal split osteotomy (BSSO), and to investigate what factors affect this MC visibility. We assessed MC visibility on panoramic radiographs of 200 BSSO patients. Images were acquired preoperatively (T0), immediately postoperatively (T1), 6months postoperatively (T2), and 1year postoperatively (T3), from three different predetermined regions of the mandible: the angle (Angle), distally to the second molar (M2), and mesially to the first molar (M1). All analyses were performed using SAS version 9.22. The visibility of the MC was registered preoperatively in over 96% (387/400) of the measurements at the angle of the mandible, 79% (317/400) at M2, and <63% (251/400) at M1. MC visibility decreased immediately after the operation and increased thereafter. Region of the mandible (P≤0.0001), plate removal (P≤0.0001), time of assessment (P≤0.0001), and age (P=0.0034) were the important predictors of whether MC would be radiographically visible. The visibility of the MC decreased immediately after BSSO, especially at the operation site (M2 and M1), while maximum MC visibility was achieved at 12months postoperatively in our series. Since MC was not visible at the operation site after BSSO for 50% of the subjects, it may be necessary to use additional visualization modalities for postoperative patient assessment in this region.

Comparison of Orthopantomography and Computed Tomography Image for Assessing the Relationship between Impacted Mandibular Third Molar and Mandibular Canal

Permanent mandibular third molar are most commonly impacted teeth. In planning the surgical removal of mandibular third molar, correct diagnosis requires not only their precise spatial location, but also a thorough and accurate assessment of the intimate relationship with adjacent anatomical structures. Various imaging modalities have been used for localizing the mandibular third molar but not satisfactorily. This prospective study of 30 patients with 42 impacted mandibular third molars was carried out with the aim of finding evidence for justifying the use of computed tomography and orthopantomography as a diagnostic modality, prior to surgical intervention of impacted mandibular third molar. Subjective evaluation of the CT and OPG images by two observed had shown that there was significant difference between the CT and OPG for radiographic visibility of mandibular canal in relation to third molar. Data analysis was done with Chi-square test (X(2)) and z-test to find the significant difference between the two radiographic modalities OPG and CT in localizing special relationship of impacted mandibular third molar. The comparison of OPG and CT showed z-value >1.5 in darkening of roots (1.98), deflection of root (2.00) interruption of z-value = 0 in narrowing of canal and dark, bifid apexes. Also it showed p-value <0.05 in all the radiographic signs except narrowing of mandibular canal and and dark and bifid apexes. The spiral CT image provides a unique opportunity to determine the exact position of impacted mandibular third molar and their relationship to adjacent structure in all three planes. Computed tomography is highly instrumental in depicting the relationship of mandibular third molar with inferior alveolar nerve canal before treatment and accurate appraisal of the several aspects can be made regarding prognosis.

Assessment of variations of the mandibular canal through cone beam computed tomography

The neurovascular bundle may be vulnerable during surgical procedures involving the mandible, especially when anatomical variations are present. Increased demand of implant surgeries, wider availability of three-dimensional exams, and lack of clear definitions in the literature indicate that features of anatomical variations should be revisited. The objective of the study was to evaluate features of anatomical variations related to mandibular canal (MC), such as bifid canals, anterior loop of mental nerve, and corticalization of MC. Additionally, bone trabeculation at the submandibular gland fossa region (SGF) was assessed and related to visibility of MC. Cone beam computed tomography exams from 100 patients (200 hemimandibles) were analyzed and the following parameters were registered: diameter and corticalization of MC; trabeculation in SGF region; presence of bifid MC, position of bifurcations, diameter, and direction of bifid canals; and measurement of anterior loops by two methods. Corticalization of the MC was observed in 59% of hemimandibles. In 23%, MC could be identified despite absence of corticalization. Diameter of MC was between 2.1 and 4mm for nearly three quarters of the sample. In 80% of the sample trabeculation at the SGF was either decreased or not visible, and such cases showed correlation with absence of MC corticalization. Bifid MC affected 19% of the patients, mostly associated with additional mental foramina. Clinically significant anterior loop (>2mm of anterior extension) was observed in 22-28%, depending on the method. Our findings, together with previously reported limitations of conventional exams, draw attention to the unpredictability related to anatomical variations in neurovascularization, showing the contribution of individual assessment through different views of three-dimensional imaging prior to surgical procedures in the mandible.