Computed tomography versus single-contrast arthrotomography in evaluation of the temporomandibular joint disc: A study of autopsy specimens

The lateral, central and medial parts of 15 right temporomandibular joint autopsy specimens were studied to compare the ability of computed tomography (CT) and single-contrast arthrotomography in diagnosing the disc position and configuration. The radiologic findings were compared with macroscopic findings in a blinded fashion. In the CT examination, the diagnostic accuracy was 40% in determining the disc position and 26.7% in determining the disc configuration. However, in many areas of the joints the disc was not possible to evaluate by CT. With arthrotomography the diagnostic accuracy in determining the disc position was 75.6% and the disc configuration 60%. The sensitivity of CT was 0.45 and of arthrotomography 0.95 for the diagnosis of the disc position. The specificity was 0.87 for CT and 0.76 for arthrotomography. From these results, we conclude that arthrotomography is a reliable aid to diagnosis of TMJ disc changes and that CT cannot replace it.     

Comparison of Endodontic Diagnosis and Treatment Planning Decisions Using Cone-beam Volumetric Tomography Versus Periapical Radiography

Introduction

Accurate and confident treatment planning is an essential part of endodontic practice. Periapical radiographs have been used to aid in the diagnosis of pathology and to help establish an appropriate treatment strategy. Recently, a new imaging modality, cone-beam volumetric tomographic (CBVT) imaging, has been shown to be a useful tool in a number of endodontic applications. The aim of this study was to compare the relative value of preoperative periapical radiographs and CBVT scanning in the decision-making process in endodontic treatment planning.

Methods

Thirty endodontic cases completed in a private endodontic practice were randomly selected to be included in this study. Each case was required to have a preoperative digital periapical radiograph and a CBVT scan. Three board-certified endodontists reviewed the 30 preoperative periapical radiographs. Two weeks later, the CBVT volumes were reviewed in random order by the same evaluators. The evaluators were asked to select a preliminary diagnosis and treatment plan based solely on their interpretation of the periapical and CBVT images. Diagnosis and treatment planning choices were then compared to determine if there was a change from the periapical radiograph to the CBVT scan.

Results

A difference in treatment plan between the 2 imaging modalities was recorded in 19 of 30 cases (63.3%, P = .001), 17 of 30 cases (56.6%, P = .012), and 20 of 30 cases (66.7%, P = .008) for examiners 1, 2, and 3, respectively.

Conclusions

Under the conditions of this study, preoperative CBVT imaging provides additional information when compared with preoperative periapical radiographs, which may lead to treatment plan modifications in approximately 62% of the cases.     

Stafne bone cavities: systematic algorithm for diagnosis derived from retrospective data over a 5-year period

Stafne bone cavities are usually found in men 50–70 years old. Typically they appear as lingual, open, ovoid lesions of the molar region of the lower jaw, and most contain parts of the submandibular gland. We have retrospectively examined panoramic radiographs acquired over a 5-year period. All lesions suspected of being Stafne bone cavities were included and analysed further to retrieve statistical information and derive a systematic diagnostic algorithm. We identified 21 Stafne bone cavities among 2928 patients (0.7%). Four of these were confirmed on cone-beam computed tomography (CT). One patient had magnetic resonance imaging (MRI) to confirm the diagnosis. The M:F ratio was 14:7 and the mean age 53 years (range 22–82). All cavities were located in the posterior mandible, 9 on the right and 12 on the left. The mean length was 10.9 (range 4.5–23) mm and height 5.7 (range 3.3–17.3) mm. All cavities were located in the posterior mandible. Sixteen panoramic radiographs (0.6%) were classified as possibly having a Stafne bone cavity but did not fulfil enough criteria to confirm the diagnosis. These 16 were not further analysed. It is rare to diagnose a Stafne bone cavity on a panoramic radiograph. Thorough investigation is essential to exclude differential diagnoses such as keratocystic odontogenic tumour, ameloblastoma, or a metastasis.     

Localization of impacted maxillary canines using cone beam computed tomography. Review of the literature

This review analyzed the literature focused on Cone- Beam Computed Tomography (CBCT) diagnostic accuracy and efficacy in detecting impacted maxillary canines, and evaluated the possible advantages in using CBCT technique compared with traditional radiographs. PubMed and Embase searches were performed selecting papers since 1998 up to September 2011, moreover reference lists were hand searched. Two reviewers selected relevant publications on the basis of predetermined inclusion criteria. The literature search yielded 94 titles, of which 5 were included in the review. Three studies used CBCT technique to 3D localize maxillary impacted canines and assess root resorption of adjacent teeth. Other two publications compared traditional radiographs with CBCT images in the diagnosis of maxillary impacted canines. Only three studies presented the results using statistical analysis. The present review highlighted that the use of CBCT has a potential diagnostic effect and may influence the outcome of treatment when compared with traditional panoramic radiography for the assessment of impacted maxillary canines. Furthermore it underlines the need of future studies performed according with high level methodological standards, investigating diagnostic accuracy and effectiveness of CBCT in the diagnosis of maxillary impacted teeth.     

Computerized axial tomography in the diagnosis of internal derangements of the temporomandibular joint

Fourteen patients with a history of pain, clicking and locking of the temporomandibular joint were assessed clinically and by using computerized axial tomography (CAT). The findings of the clinical and CAT scan assessment were correlated and compared with surgical observations. Computerized axial tomography scanning proved to be a highly accurate method of assessing meniscal position. With the advent of more sophisticated methods of CAT scanning, it provides an accurate, non-invasive method of assessing the temporomandibular joint and providing a basis for more effective treatment planning of problems related to internal derangements.     

Accuracy of linear vs spiral tomography: Alveolar crest to sinus/nasal floor height

AIM: To determine the accuracy of tomography in the linear measurement of alveolar bone at maxillary sinus/nose location. METHODS: Two dry skulls each marked with 10 pairs of guttaperchas placed on buccal and lingual sides of the maxillary ridge were used in this in vitro study. The distance between the alveolar crest and the sinus/nasal floor was measured on tomographic views, prepared by linear and spiral techniques. The ridges were then sectioned so that each section would include one pair of buccal and lingual guttaperchas. The actual distances directly measured on the sections were compared to those of the equivalent tomographic sections (the magnification co-efficient was applied). Paired t-test was used to statistically analyze the data. RESULTS: The measurement error with the application of linear tomography and spiral tomography was shown to be 0.455 ± 0.838 mm (P = 0.029) and 0.17 ± 0.78 mm (P = 0.347), respectively. There was a statistically significant difference between the liner tomography values and actual values (P = 0.029). This difference was representative of underestimation. McNamara’s test was used to assess the ± 1 mm error; 73.7% of the linear values and 84.2% of the spiral values were within the ± 1 mm error limit. McNamara’s test did not show any significant differences between the 2 methods in this regard (P = 0.625). The linear values were significantly different to the actual values (P = 0.029) but not to the spiral values (P = 0.185). CONCLUSION: Spiral tomography has enough accuracy for the measurement of alveolar ridge height. Although linear tomography somewhat underestimates the actual values it provides satisfactory accuracy.     

Implagraphy牙颌面锥形束CT与多层螺旋CT的图像质量对比研究

目的：比较牙颌面锥形束CT与多层螺旋CT的图像质量。方法：分别使用牙颌面锥形束CT和多层螺旋CT对实验模体进行扫描，比较两者显示牙、牙周组织、颌面骨解剖结构的差异。结果：牙颌面锥形束CT图像质量，优于多层螺旋CT。结论：牙颌面锥形束CT因其优秀的图像质量，更加适合口腔临床的需要。     

The use of cone beam computed tomography in the management of isolated orbital floor fractures

Isolated fractures of the orbital floor are diagnosed by a combination of clinical and radiographic findings. Computed tomography is considered the imaging method of choice. We describe the use of cone beam computed tomography for use in isolated fractures of the orbital floor. This shows defects in the orbital floor but with a lower dose of radiation than conventional computed tomography.     

Craniomaxillofacial patient-specific CAD/CAM implants based on cone-beam tomography data – A feasibility study

Customized implants have simplified surgical procedures and have improved patient outcome in craniomaxillofacial surgery. Traditionally, patient-specific data is gathered by conventional computed tomography (CT). However, cone-beam CT (CBCT) can generate a 3D reconstruction of the area of interest with a lower dose of radiation at reduced cost. In this study, we investigated the feasibility of using CBCT data to design and generate customized implants for patients requiring craniomaxillofacial reconstruction. We used CBCT to generate 62 implants for 51 consecutive patients admitted to our department between January 2015 and December 2017. The indications for reconstruction and types of reconstruction were very variable. In all cases, the implants were well fitted and no implant-related complications were detected. Pre-surgical planning was faster and more efficient as we did not have to consult a radiologist. Although CBCT data is more difficult to process than conventional CT data for the implant provider, the clinical advantages are pronounced and we now use CBCT as standard in our department. In conclusion, we have shown that using CBCT to design and manufacture customized implants for reconstruction of the craniomaxillofacial area is feasible and recommend this approach to other departments.     

The effects of irradiation and hyperbaric oxygen on bone formation during rabbit mandibular distraction

[18F-]fluoride positron-emission tomography (PET) was used to assess bone formation during mandibular distraction osteogenesis. There were three study groups: irradiation, irradiation+hyperbaric oxygen and control. The two experimental groups received a tumoricidal dose of irradiation to the mandible, and one group was also given hyperbaric oxygen (2.5 ATA (atmospheres absolute) for 90 min) 18 times preoperatively. Control animals received neither irradiation nor oxygen. A unilateral osteotomy was made and, after a period of latency, bone distraction was started, continued for 2 weeks, and the distraction generated was then allowed to consolidate for 4 weeks. The first PET study was performed at the end of distraction and the second at the end of consolidation. At the end of distraction, the metabolic activity of bone in the distracted area was significantly higher in the controls than in either experimental group; differences between the experimental groups were not statistically significant. By the end of consolidation, activity in the control group had diminished to the same as in the two experimental groups, in which no significant change had occurred. Radioactivity was still significantly higher at second imaging on the distracted than non-distracted side in the control and irradiation+hyperbaric oxygen groups, but not in the group that was only irradiated. The results indicate that previous irradiation disturbs bone formation during mandibular distraction osteogenesis. Hyperbaric oxygen was not able to prevent the suppression of osteogenesis caused by radiotherapy but it might improve bone formation by prolonging high osteogenic activity.     

Computerized tomography in the management and follow-up of extensive periapical lesion

Abstract— Radiographs are good diagnostic aids in endodontics, although they have limitations. The purpose of this article is to discuss the use of computerized tomography in differential diagnosis, treatment planning, follow-up and overall clinical management of complex periapical lesions. A clinical case of an extensive symptomatic periapical lesion of the upper jaw is presented, in which the use of computerized tomography allowed evaluation of the true extent of the lesion and its spatial relationship to important anatomical landmarks. Computerized tomography also provided specific information about the type of lesion and the degree of bone repair which had taken place 18 months after non-surgical treatment had been completed.     

Comparison of the Accuracy of 3-dimensional Cone-beam Computed Tomography and Micro–Computed Tomography Reconstructions by Using Different Voxel Sizes

Introduction

Cone-beam computed tomography (CBCT) data are, in principle, metrically exact. However, clinicians need to consider the precision of measurements of dental morphology as well as other hard tissue structures. CBCT spatial resolution, and thus image reconstruction quality, is restricted by the acquisition voxel size. The aim of this study was to assess geometric discrepancies among 3-dimensional CBCT reconstructions relative to the micro-CT reference.

Methods

A total of 37 permanent teeth from 9 mandibles were scanned with CBCT 9500 and 9000 3D and micro-CT. After semiautomatic segmentation, reconstructions were obtained from CBCT acquisitions (voxel sizes 76, 200, and 300 μm) and from micro-CT (voxel size 41 μm). All reconstructions were positioned in the same plane by image registration. The topography of the geometric discrepancies was displayed by using a color map allowing the maximum differences to be located.

Results

The maximum differences were mainly found at the cervical margins and on the cusp tips or incisal edges. Geometric reconstruction discrepancies were significant at 300-μm resolution (P = .01, Wilcoxon test).

Conclusions

To study hard tissue morphology, CBCT acquisitions require voxel sizes smaller than 300 μm. This experimental study will have to be complemented by studies in vivo that consider the conditions of clinical practice.     

Measurement accuracy of reconstructed 2-D images obtained by multi-slice helical computed tomography

The present dental reconstructed computed tomography (CT) images consist of continuously piled-up axial CT images that are perpendicular to the axial CT plane. In the mandibular posterior region, the angles of designed implants frequently differ from the angles perpendicular to the axial CT plane and the measurement of mandibular height is inaccurate. This study was performed to clarify the measurement accuracy of double-oblique reconstructed images in multi-slice helical CT, using dried mandibles. The mandibular height was measured from the alveolar crest immediately below the aluminum tube to the superior border of the mandibular canal using the double-oblique reconstructed images and the micro-CT average images of three semi-lateral dried mandibles. The mean of the differences between the double-oblique reconstructed images with a table pitch of 1.5 in a helical scan and the micro-CT average images was 0.31 mm. It is concluded that the accuracy of the double-oblique reconstructed image measurements with helical scan is high. So this double-oblique program can be applied to the imaging diagnosis in dental implant treatment.     

Accuracy of High-resolution Small-volume Cone-beam Computed Tomography in Detecting Complex Anatomy of the Apical Isthmi: Ex Vivo Analysis

Introduction

The purpose of this study was to evaluate the accuracy of small-volume cone-beam computed tomography (CBCT) to detect and measure isthmi in the apical root canals of mandibular molars by using micro–computed tomography (μ-CT) as the reference standard.

Implant radiography and radiology

The practitioner placing dental implants has many options with respect to pre-implant radiographic assessment of the jaws. The advantages and disadvantages of the imaging modalities currently available for pre-implant imaging are discussed in some detail. Intra-oral and extra-oral radiographs are generally low dose but the information provided is limited as the images are not three-dimensional. Tomography is three-dimensional, but the image quality is highly variable. Computed tomography (CT) has been the gold standard for many years as the information provided is three-dimensional and generally very accurate. However, CT examinations are expensive and deliver a relatively high radiation dose to the patient. The latest imaging modality introduced is cone beam volumetric tomography (CBVT) and this technology is very promising with regard to pre-implant imaging. CBVT generally delivers a lower dose to the patient than CT and provides reasonably sharp images with three-dimensional information. A comparison between CT and CBVT is provided. Magnetic resonance imaging is showing some promise, but the examinations are not readily available, generally expensive and bone is not well imaged. Magnetic resonance imaging is excellent for demonstrating soft tissues and therefore may be of great use in identifying the inferior dental nerve and vessels. All of the above technology is of little value if the information required is not obtained and so information is also provided on imaging of some of the vital structures. Of particular interest is the inferior dental canal, incisive canals of the mandible, genial foramina and canals, maxillary sinus and the incisive canal and foramen of the maxilla.