Christos Angelopoulos

Comparison between digital panoramic radiography and cone-beam computed tomography for the identification of the mandibular canal as part of presurgical dental implant assessment.

PURPOSE A variety of imaging modalities (eg, panoramic radiography, tomography, or computed tomography [CT]) were compared for their efficiency in the identification of the mandibular canal. The recently introduced cone-beam computed tomography (CBCT) seems to be a promising imaging modality which also reduces patient exposure considerably, compared with ordinary CT. The literature includes no studies comparing its performance in such delicate tasks as mandibular-canal identification with other traditionally used imaging modalities. The goal of this study was to compare CBCT reformatted panoramic images and digital panoramic images for the identification of the mandibular canal as part of preimplant assessment. MATERIALS AND METHODS Panoramic images, generated by 3 different imaging modalities used for general maxillofacial diagnosis and preimplant assessment, were compared: CBCT reformatted panoramic images (I-CAT; Imaging Sciences, Hatfield, PA), direct (charge-coupled device-based) panoramic radiographs (DIMAX; Planmeca, Helsinki, Finland), and digital panoramic radiographs based on a storage phosphor system (DENOPTIX; Gendex, Chicago, IL). We used 3 independent groups of images (40 in each group) from patients examined by one of the above imaging modalities over a period of 6 months. In total, 68 randomly selected mandibular canals (out of a possible 80) per imaging modality were evaluated. Four experienced raters evaluated the images of each modality in 3 sessions under standardized conditions for clarity in the visualization of the mandibular canal in 3 locations, using a 4-point scale. RESULTS The CBCT reformatted panoramic images outperformed the digital panoramic images in the identification of the mandibular canal. CONCLUSIONS Due to the fact that the CBCT images were reformatted slices of the maxilla and mandible, they were free of magnification, superimposition of neighboring structures, and other problems inherent to panoramic radiology. This may result in very clear images that better depict the mandibular canal.

American Academy of Oral and Maxillofacial Radiology executive opinion statement on performing and interpreting diagnostic cone beam computed tomography

The American Academy of Oral and Maxillofacial Radiology (AAOMR) is the professional organization representing oral and maxillofacial radiologists in the United States. The Academy is a nonprofit professional society the primary purposes of which are to advance the science of radiology, improve the quality and access of radiologic services to the patient, and encourage continuing education for oral and maxillofacial radiologists, dentists, and persons practicing oral and maxillofacial imaging in allied professional fields. The AAOMR embraces the introduction of cone beam computed tomography (CBCT) as a major advancement in the imaging armamentarium available to the dental profession. The AAOMR is currently in the process of developing a position paper on appropriate application of CBCT to provide evidence-based guidelines. In the interim, the Executive Committee (EC) of the AAOMR considers it necessary to provide an opinion document addressing the principles of application of CBCT as it relates to acquisition and interpretation of maxillofacial imaging in dental practice.

Cone Beam Tomographic Imaging Anatomy of the Maxillofacial Region

Multiplanar imaging is a fairly new concept in diagnostic imaging available with a number of contemporary imaging modalities such as CT, MR imaging, diagnostic ultrasound, and others. This modality allows reconstruction of images in different planes (flat or curved) from a volume of data that was acquired previously. This concept makes the diagnostic process more interactive, and proper use may increase diagnostic potential. At the same time, the complexity of the anatomical structures on the maxillofacial region may make it harder for these images to be interpreted. This article reviews the anatomy of maxillofacial structures in planar imaging, and more specifically cone-beam CT images.

A Comparison of Maxillofacial CBCT and Medical CT

In 1972, the independent findings of Hounsfield and Cormack revolutionized diagnostic imaging with the invention of the computed tomography (CT) scanner [1,2]. For the first time, practitioners had access to x-ray devices that could generate narrow cross-sectional images, usually perpendicular to the long axis of the human body, hence, the term computed axial tomography or CAT scan. This technology, fan-beam CT, was the first practical electronic application of the tomographic principal in diagnostic imaging [3] and provided images that eliminated the superimposition of adjacent anatomic structures inherent in conventional plain projection radiography and the blur of analog tomography. The availability of CT images facilitated new perspectives in imaging diagnosis by reducing much of the guesswork that was often interlaced with projection imaging. CT is now an essential imaging modality of the diagnostic algorithm for an increasing variety of clinical applications [4]. CT acquisition has subsequently been refined to incorporate a helical or spiral synchronous motion, fan-shaped beam, and multiple detector acquisition (MDCT), which enables fast scan times that provide highquality images that can be integrated to produce a volumetric dataset. Although CT has been available for more than 4 decades, its clinical applications in dentistry have been limited because of the high equipment cost, limited access because of the certificate-of-need requirements in some jurisdictions, and radiation dose considerations (Fig. 1A). Cone-beam computed tomography (CBCT) presents as a separate evolutionary arm to CT imaging. An early volumetric CT predecessor of CBCT, the Dynamic Spatial Reconstructor, was developed in the late 1970s by the Biodynamics Research Unit at the Mayo Clinic [5]. Subsequently applied for vascular imaging [6], CBCT prototypes based on C-arms were demonstrated as early as 1983. CBCT provided an alternate method of cross-section image production to fan-beam CT using a comparatively less-expensive radiation detector than conventional CT. The technology transfer of CBCT to dentistry first occurred in 1995. Italian co-inventors, Attilio Tacconi and Piero Mozzo, developed a CBCT system for the maxillofacial region that was designed and produced by QR, Inc of Verona, Italy. This unit, the NewTom DVT 9000 became the first commercial CBCT unit marketed specifically to the dental market, initially introduced in Europe in 1999. Although with little more than a decade of application in dentistry, CBCT has revolutionized oral and maxillofacial imaging. Similarities exist between technologies; however, differences in the image acquisition beam shape, as well as the x-ray generator and detecting system used, make CBCT stand independently as a simple and inexpensive approach to the concept of electronic sectional imaging focusing mostly on the maxillofacial region. This development has resulted in the clinical availability of a cross-sectional technology capable, for the most part, of providing members of the dental profession with a comparatively inexpensive 3-dimensional (3D) imaging modality, both in terms of cost and radiation burden. Although the first CBCT generation was similar to fan-beam CT in that image

Imaging technology in implant diagnosis.

Dental implantology based on osseointegration is among the most significant advances in dental science in the last 50 years. Imaging technology contributes to all stages of implant treatment, from presurgical site evaluation to postoperative assessment of integration, and long-term periodic evaluation of implant status. Various imaging modalities have been used for dental implant assessment in the different stages of implant treatment. These include intraoral radiography (film-based and digital), panoramic radiography, computed tomography, cone-beam computed tomography, and others. Selection of the specific imaging technique should be based on its suitability for providing the diagnostic information required by the implant team at different stages of treatment. This article reviews the applications of different imaging technologies and their diagnostic contribution to presurgical evaluation, treatment planning, and postoperative assessment of dental implants.

Immediate Flapless Implant Placement and Provisionalization: Challenge for Optimum Esthetics and Function: A Case Report

This report presents a case of tooth extraction and immediate flapless implant placement followed by fabrication of transitional restoration. The tooth was extracted atraumatically with the use of a periotome followed by careful debridement. An osteotomy was performed up to 5 mm beyond the base of the socket and depth using the alveolar crest as a landmark, following a slightly palatal direction. The implant shoulder was inserted 3 mm below the cementoenamel junction of the adjacent tooth. The interproximal distance from the neighboring teeth was 3 mm. No membranes and/or grafts were used. Initial impressions were taken immediately after implant placement; 6 hours later a well-polished and slightly overcontoured (at the distal-mesial aspect) acrylic crown was fixed onto the implant. There were no contacts in the centric and lateral positions. Five months later, the occlusion was modified allowing slight contacts in the centric position for an additional 2 months. The final prosthetic restoration was placed 2 months later (7 months after surgery), consisting of a full ceramic crown cemented on a customized metal ceramic UCLA abutment. The technique maintained the integrity of hard and soft tissues and created a very favorable esthetic result. It also provided the patient with a transitional fixed restoration and reduced the time required for therapy completion. Because research on this field is limited, further investigation is required to support the results of this report, despite the promising clinical outcome.

Cherubism: A Case Report of a Three-Generation Inheritance and Literature Review

Cherubism is a rare, non-neoplastic pathologic entity first described by Jones in 1933. It affects mostly younger individuals and is usually inherited. Cherubism presents as a painless jaw enlargement that affects both the maxilla and the mandible and is characterized by replacement of the osseous tissue by fibrous connective tissue. Radiologically, the lesions appear as multiple, multilocular radiolucent spaces with distinct borders divided by bony septations, which often dramatically alter the shape and size of the jaw structures. These often result in marked facial abnormalities. Cervical lymphadenopathy is not uncommon in those affected. The disease is self-limited and can reverse itself with time. Approximately 250 cases have been reported in published studies, mostly affecting males. The purpose of our report was to present a case of cherubism diagnosed in a young girl and the long-term (3 generations) follow-up evaluation of her mother and grandmother, both of whom had been diagnosed with the same pathologic entity.

Anatomy of the Maxillofacial Region in the Three Planes of Section

Apart from a few exceptions, dental practitioners are not familiar with sectional images (as those provided by cone beam computed tomography [CBCT]). In addition, the maxillofacial region is a complex area from an anatomic point of view including structures of peculiar shape; this may add to that complexity of their appearance in CBCT. As a result, a thorough knowledge of the tomographic anatomy of the maxillofacial region was necessary. This chapter reviews pertinent anatomical structures of the maxillofacial region in the axial, coronal, sagittal planes, as well as custom planes. Related pathology is also shown and discussed.

Cone Beam Computed Tomography and Maxillofacial Diagnosis

Diagnostic radiologic image analysis or interpretation is a critical stage in the diagnostic process for the assessment of any pathologic condition (Table 15.1). The role of imaging in this sequence is to: (1) assist and/or confirm a suspected diagnosis, (2) provide direction towards the appropriate management of the condition, (3) identify surgical parameters of importance (e.g., pathologic margins, involvement of important anatomical structures such as the inferior alveolar canal), and (4) determine the effectiveness of a specific management strategy treatments with periodic assessment (postoperative follow-up radiographic examinations.

Ultrasound in Dentistry: Toward a Future of Radiation-Free Imaging

Ultrasonography (US) is a noninvasive, nonionizing, inexpensive, and painless imaging tool proven to be a valuable diagnostic tool in soft tissue assessment that also shows promise for hard tissue evaluation in dentistry. US has been investigated for its capability to identify carious lesions, tooth fractures or cracks, periodontal bony defects, maxillofacial fractures, and more. It has been used as a diagnostic aid in temporomandibular disorders, implant dentistry, and to measure muscle and soft tissue thickness. Unfortunately, the use of US in dentistry is still in its infancy; however, relevant research is promising.