Rujuta A. Katkar

Comparison of observer reliability of three-dimensional cephalometric landmark identification on subject images from Galileos and i-CAT cone beam CT

OBJECTIVES Recently, there has been increasing interest in the use of cone beam CT (CBCT) for three-dimensional cephalometric analysis and craniofacial reconstruction in orthodontic and orthognathic surgical treatment planning. However, there is a need to redefine the cephalometric landmarks in three dimensional cephalometric analysis and to demonstrate the reproducibility of landmark identification on the type of CBCT machine being used. METHODS CBCT images of 20 subjects aged 15-25 years were selected, ten each from Galileos(®) (Sirona Dental Systems Inc., Bensheim, Germany) and Next Generation i-CAT(®) (Imaging Sciences International, Hatfield, PA). 2 observers located 18 landmarks on each subject twice using Dolphin-3D v. 11 software (Dolphin Imaging and Management Systems, Chatsworth, CA). Inter- and intraobserver reliability was assessed using Euclidean distances and linear mixed models. RESULTS Overall, the intra- and interobserver reliability was excellent for both machines. The landmarks Gonion, Nasion, Orbitale and Anterior Nasal Spine (ANS) showed the greatest median Euclidean distances for both intra- and interobserver measurements. There were significant observer effects in the unified models for Sella, Menton and all six dental landmarks. For Sella, the distances between the measures were significantly smaller (more closely spaced) on the i-CAT machine than on the Galileos in both intra- and interobserver measurements. CONCLUSIONS The intra- and interobserver reliability was excellent for both machines. Some of the landmarks were not as reproducible as others. Which machine produced the highest reliability depended on the landmark considered.

Incidental findings of skull-base abnormalities in cone-beam computed tomography scans with consultation by maxillofacial radiologists

INTRODUCTION Cone-beam computed tomography (CBCT) gives orthodontists and other dental clinicians 3-dimensional information for planning treatment in the craniofacial region. Often overlooked are incidental findings outside the treatment region of interest. METHODS Two patients with incidental findings of skull-base abnormalities are presented. The orthodontic patient was tentatively diagnosed with a notochordal remnant in the clivus; the implant patient exhibited an empty sella turcica. RESULTS For the clivus lesion in the orthodontic patient, an artifact was ruled out after a second CBCT image and further distinguished from a fat-containing tumor after magnetic resonance imaging. The impression after magnetic resonance imaging was a notochordal remnant, although chordoma was also included in the differential, warranting a 6-month follow-up magnetic resonance image to confirm the diagnosis. The CBCT study for the implant patient demonstrated an enlarged sella turcica. The impression after the magnetic resonance imaging was an enlarged and partially empty sella with no evidence of a pituitary mass. CONCLUSIONS Orthodontists and implant surgeons may come across incidental findings outside their area of expertise on CBCT scans, highlighting the importance of appropriate consultation with maxillofacial radiologists. Notochordal remnants may present as nonexpansile intraosseous low-density areas. The challenge in distinguishing these lesions radiographically with chordomas warrants follow-up to confirm a diagnosis. An empty sella is a noteworthy finding because of its potential for endocrine and neuro-ophthalmological disorders despite an asymptomatic presentation.

Configuration of the inferior alveolar canal as detected by cone beam computed tomography.

Aims: The aim of this study is to evaluate the course of the inferior alveolar canal (IAC) including its frequently seen variations in relation to root apices and the cortices of the mandible at fixed pre-determined anatomic reference points using cone beam volumetric computed tomography (CBVCT). Material and Methods: This retrospective study utilized CBVCT images from 44 patients to obtain quantifiable data to localize the IAC. Measurements to the IAC were made from the buccal and lingual cortical plates (BCP/LCP), inferior border of the mandible and the root apices of the mandibular posterior teeth and canine. Descriptive analysis was used to map out the course of the IAC. Results: IACs were noted to course superiorly toward the root apices from the second molar to the first premolar and closer to the buccal cortical plate anteriorly. The canal was closest to the LCP at the level of the second molar. In 32.95% of the cases, the canal was seen at the level of the canine. Conclusions: This study indicates that caution needs to be exercised during endodontic surgical procedures in the mandible even at the level of the canine. CBVCT seems to provide an optimal, low-dose, 3D imaging modality to help address the complexities in canal configuration.

Mesially Inclined Third Molars May or May Not Be Associated With External Root Resorption in Adjacent Second Molars.

Article Title and Bibliographic Information Mesial inclination of impacted third molars and its propensity to stimulate external root resorption in second molars – a cone-beam computed tomographic evaluation. Oenning AC, Melo SLS, Groppo FC, Haiter-Neto F. J Oral Maxillofac Surg 2015;73(3):379-386. Reviewer Rujuta A. Katkar, BDS, MDS, MS, Dipl. ABOMR Purpose/Question Prevalence of external root resorption in second molars adjacent to horizontally and mesioangular impacted third molars using cone-beam computed tomography (CBCT) scans. Source of Funding Information not available Type of Study/Design Retrospective cross-sectional radiographic study Level of Evidence Level 3: Other evidence Strength of Recommendation Grade Not applicable

Arrested Pneumatization of the Sphenoid Sinus on Large Field-of-View Cone Beam Computed Tomography Studies

Arrested pneumatization of the sphenoid sinus is a normal anatomical variant. The aim of this report is to define cone beam computed tomography (CBCT) characteristics of arrested pneumatization of sphenoid sinus in an effort to help differentiate it from invasive or lytic skull base lesions. Two cases are presented with incidental findings. Both studies, acquired for other diagnostic purposes, demonstrated unique osseous patterns that were eventually deemed to be anatomic variations in the absence of clinical signs and symptoms although the pattern of bone loss and remodeling was diagnosed as pneumatization of the sphenoid sinus by a panel of medical and maxillofacial radiologists following contrasted advanced imaging. It is important to differentiate arrested pneumatization of the sphenoid sinus from lesions, such as arachnoid granulations, acoustic neuroma, glioma, metastatic lesions, meningioma, or chordoma, to prevent unnecessary biopsies or exploratory surgeries that would consequently reduce treatment costs and alleviate anxiety in patients.

Multiple myeloma in bisphosphonate-affected jaws - a diagnostic challenge: Case report

OBJECTIVE To discuss the challenges in diagnosis and appropriate management of critical underlying pathoses if a patient presents with signs and symptoms indicative of different conditions that may coexist. SUMMARY This case features clinical and radiographic challenges in reaching a diagnosis in a middle- aged man undergoing bisphosphonate therapy for multiple myeloma. The patient had history of bisphosphonaterelated osteonecrosis of the jaw (BRONJ) in the mandible. The patient presented with pain and swelling in the anterior maxilla, associated with paresthesia of upper lip. The radiographic features were suggestive of BRONJ and invasive fungal sinusitis. MRI appearance was suggestive of malignant involvement by plasmacytoma or lymphoma. Although biopsy is usually not advocated in bisphosphonate-affected jaws, it was advised in this case and was positive for multiple myeloma. Vigilance is required to correlate clinical and radiologic findings and further investigations must be considered if malignancy is suspected.

3D Volume Rendering and 3D Printing (Additive Manufacturing)

Three-dimensional (3D) volume-rendered images allow 3D insight into the anatomy, facilitating surgical treatment planning and teaching. 3D printing, additive manufacturing, and rapid prototyping techniques are being used with satisfactory accuracy, mostly for diagnosis and surgical planning, followed by direct manufacture of implantable devices. The major limitation is the time and money spent generating 3D objects. Printer type, material, and build thickness are known to influence the accuracy of printed models. In implant dentistry, the use of 3D-printed surgical guides is strongly recommended to facilitate planning and reduce risk of operative complications.

Optical Coherence Tomography

Optical coherence tomography (OCT) is a noninvasive diagnostic technique providing cross-sectional images of biologic structures based on the differences in tissue optical properties. OCT has been widely used in numerous clinical applications and is becoming popular as a promising technology in dentistry. Today, dental hard (tooth) and soft (hard palate mucosa and gingiva mucosa) tissues are visualized with OCT. With new developments in technology, the applications of OCT are being investigated in various fields in dentistry, such as to detect microleakage around restoration, tooth cracks/fractures, examination of periodontal tissues/pockets, early detection of oral cancerous tissues, and in endodontics for location of pulp canal.