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JADA Specialty Scan - Radiology
Radiology - A Quarterly Newsletter on Dental SpecialtiesJADA Specialty Scan

Understanding osteonecrosis of the jaws

Scientists published an exploration of the signs, symptoms and treatment strategies associated with osteonecrosis of the jaws, as well as a discussion of potential factors leading to disease development in the Sept. 24, 2015, electronic edition of Oral and Maxillofacial Surgery Clinics of North America.

The team of scientists from the University of California, Los Angeles, reviewed the literature to examine hypotheses for ONJ pathophysiology. Although significant progress has been made in understanding the disease, much more work needs to be done to completely explain it, authors said, noting the first ONJ cases were reported as recently as 2003 and 2004.

“Many hypotheses have been proposed, which have sparked empirically based treatment modalities. Because it is unlikely that one single hypothesis can explain the pathophysiology of ONJ, as it is indeed multifactorial, it is also unlikely that one treatment modality will be successful on all patients,” authors said prior to elucidating hypotheses. They noted that theories and treatment approaches will need to be continuously modified as more evidence becomes available.

Scientists reported on five assumptions for ONJ development: bone-remodeling inhibition (the leading hypotheses); inflammation and infection; angiogenesis inhibition; soft tissue toxicity; and innate or acquired immunity dysfunction. Within each category they discuss the evidence and note remaining questions. Scientists also created a schematic diagram illustrating the complexity of ONJ and the potential synergy of multiple pathways, with histologic bone necrosis at the center of the disease process.

They reported that altered bone remodeling as a result of bisphosphonate or denosumab use is the leading hypothesis for ONJ development. Such drugs have direct effects on osteoclasts to inhibit their function and reduce bone breakdown. Osteoclast differentiation and function play vital roles in bone healing and remodeling at all skeletal sites, but ONJ occurs only in alveolar bone of the maxilla and mandible. Some research shows that alveolar bone may demonstrate an increased remodeling rate as compared with other bones in the axial or appendicular skeleton, which may explain ONJ predilection in the jaws. However, other studies have failed to confirm differences in bone turnover between the mandible and femur.

Scientists point out that additional inciting factors besides antiresorptives contribute to ONJ. Although tooth extraction is generally the most common, teeth in adults are almost always extracted because they have periapical or periodontal infections or inflammation. In patients with multiple myeloma and metastatic cancer, aggressive dental hygiene therapy reduces the incidence of ONJ. Authors contend, “However, the question remains:  Did the bacteria induce the infection and exposed bone, or did the exposed bone develop a bacterial biofilm?”

Antiangiogenic therapies inhibit the growth of new capillary blood vessels and are associated with ONJ development. Antiangiogenic therapies are now widely used to inhibit tumor invasion and metastases, targeting vascular signaling molecules. The prevalence of ONJ is highest in patients with multiple myeloma, which is thought to be caused by attendant antiangiogenic medications and steroids. “Although unlikely to be central in the development of ONJ, antiangiogenesis is thought to be a significant contributor to the disease process,” authors reported.

An early hypothesis in ONJ pathophysiology was direct soft tissue toxicity of bisphosphonates. Authors reported that this hypothesis has become less likely due to the lack of soft tissue toxicity reported with denosumab use.

Authors discuss the continuing debate on the effect of altered immunity on ONJ development, with evidence that the highest prevalence of ONJ is in patients with multiple myeloma who receive steroids and antiangiogenics as part of their chemotherapy regimen, further pointing to a role of immune dysfunction.

Authors reported a comprehensive summary of findings and concluded it with: “Understanding pathophysiologic mechanisms of ONJ will help explore targeted treatment interventions to reduce development and improve management of patients with established disease.”

Read the original article.


Consulting Editor: Laurie C. Carter, DDS, PhD
Past president, American Academy of Oral and Maxillofacial Radiology

Selecting patients for carotid ultrasonography

Carotid stenosis is a risk factor for ischemic stroke and its early diagnosis can reduce stroke risk. Although carotid plaques are often somewhat calcified and can be seen on panoramic radiographs, these images are only moderately accurate at identifying patients with carotid stenosis.

A team of scientists in Sweden seeking to interpret panoramic radiographs in ways that would improve patient selection for screening of carotid stenosis by carotid ultrasonography conducted a study and published their findings in the August 2015 issue of Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology.

The scientists aimed to determine calcium volume in carotid plaques and find out if calcium volume is associated with the degree of stenosis. They also wanted to know if calcium volume influences detection of carotid calcifications on panoramic radiographs.

To investigate, scientists examined 97 patients (68 men and 29 women), with ultrasonography-verified carotid stenosis by panoramic radiography prior to performing carotid endarterectomy surgery.  A total of 103 carotid plaques were removed. Average patient age was 70 years old, the youngest age 52 and the oldest age 86.

Scientists removed plaques from arteries, examined them with cone beam computed tomography and determined the calcium volume. They analyzed the association between calcification quantity and degree of stenosis, gender, symptomatic or asymptomatic carotid plaques and age. They further analyzed the possibility to detect carotid calcifications on panoramic radiographs by comparing findings of calcifications with the calcification volume in the corresponding removed plaques.

Among results, scientists found calcification in 102 of the 103 removed plaques, with calcification volumes ranging in size from 1 millimeter3 (mm), to a maximum of 509 mm3 and a median of 45 mm3. They found no statistically significant associations between calcification volumes and degree of stenosis, gender, symptomatic or asymptomatic carotid stenosis or age. They observed no statistically significant association between the amount of calcification and the total plaque size. Of 102 calcified plaques, 78 were situated within the region depicted by panoramic radiography. Of these, 77 (99 percent) were identified in the radiographs.

Discussion points included that regardless of size, all carotid calcifications observed on panoramic radiographs can represent a clinically relevant carotid stenosis, and all appearances must be considered in determining the need for further diagnostic evaluation. Addressing growing interest in typing plaque features for indication of carotid endarterectomy in asymptomatic patients, authors said their data showed no association between calcification quantities and whether the carotid stenosis was symptomatic or not.

Among conclusions, authors called for further research. “We have to identify additional factors other than the amount of carotid calcification on panoramic radiographs, to be able to extract a subpopulation with carotid calcification with a prevalence of significant carotid stenosis that motivates referral for ultrasonographic examination.”

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Free eBook on Exposure and Expectations

Managing dose in digital imaging is necessary to better understand how to bridge the gap between clinically valuable images and patient safety. In this eBook you will learn: how radiation is measured; how to determine the right dose; strategies for optimizing dose and not losing image quality. Click here for more information.


Sharing dental images

Dental practice is swamped with data.

“Initially limited to textual and numerical information, digital imaging in dentistry over the last 20 years, most recently with cone beam computed tomographic data, has ballooned the dental electronic health record (d-EHR) from the kilobyte to the terabyte range and beyond.”

That’s the author of a paper published in the April 2015 issue of Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology. Finding student and clinician knowledge about medically related email communications lacking, the section editor of Oral and Maxillofacial Radiology proceeded to provide a framework of understanding for practitioners in the U.S.

Although computer systems can handle all aspects associated with acquisition, management, storage and retrieval of data, there are many restrictions when it comes to distribution of data, particularly when it comes to sharing personal health information, including dental radiographic images, he explained.

The author described practical compliance methods for email communication and distribution of dental radiographic images under the 1996 Health Insurance Portability and Accountability Act requirement to ensure that communications protect the privacy and security of an individual’s personal health information in electronic form. He elaborated on the discussion to include additional regulatory expansion that has complicated the issue for dentists, including the HIPAA Privacy Rule, the HIPAA Security Rule, the Health Information Technology for Economic and Clinical Health Act and the Privacy and Security Omnibus Rule.

His paper describes useful resources and initiatives developed by the American Dental Association, specialty organizations, other agencies, vendors and individuals. The author advocated and called for continued collaborations between clinicians and industry to provide workable practical solutions to clinical problems in dental information technology.

Read the original article.


Specialty organizations update joint CBCT statement

Radiography has long been recognized as essential for the successful diagnosis of endodontic disease. Until recently, radiographic assessments were limited to intraoral and panoramic radiography, which provide two-dimensional representations. Cone beam computed tomography allows practitioners to view the dentition, the maxillofacial skeleton and the relationship of anatomy in three dimensions. The ability to evaluate structures in multiple planes and three-dimensionally means dental practitioners may be able to more accurately interpret complex anatomy and surrounding structures.

However, as with any technology, CBCT has known limitations, which include possible higher radiation doses to patients, the potential for artifact creation, high levels of scatter and noise and variations in dose distribution within the volume of interest.

Seeking to respond to new developments and research about the effectiveness of 3-D imaging for endodontic diagnosis and treatment, the American Association of Endodontists and the American Academy of Oral and Maxillofacial Radiology issued a revised joint position statement on the use of CBCT in endodontics. The Special Committee to Revise the Joint AAE/AAOMR Position on Cone Beam Computed Tomography published the statement in the October 2015 issue of Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology.

This update to the 2010 statement emphasizes that CBCT should not be used routinely for endodontic diagnosis or screening purposes in the absence of clinical signs and symptoms or when the need for imaging can be met by lower dose two-dimensional radiography. “CBCT should be used only when the patient’s history and a clinical examination demonstrate that the benefits to the patient outweigh the potential risks.”

The statement says the most appropriate imaging protocol for the diagnostic task must be consistent with the principles of ALARA — keeping patient radiation doses “as low as reasonably achievable.”

Field of view and dose considerations are examined and elucidated with 12 specific recommendations and adjoining supporting evidence for imaging modality. Recommendations and rationale pertain to diagnosis, initial treatment, nonsurgical treatment, surgical treatment and special conditions (implant placement, traumatic injuries, resorptive defects).

Read the original article.

OP300 Maxio Imaging System

With the ORTHOPANTOMOGRAPH OP300 Maxio, dental professionals have access to an advanced 2D/3D solution with gold standard, panoramic, cephalometric and cone beam digital imaging. The feature-rich OP300 Maxio now offers Instrumentarium ADC, Automatic Dose Control, for 2D panoramic X-rays and cone beam 3D scans! Low Dose Technology, flexible field-of-view positioning and award winning 3D software make this system a must see. OP300 Maxio offers five FOV sizes ranging from 5 x 5 cm up to 13 x 15 cm for dental professionals wanting to view small details up through the entire maxillofacial region including the temporomandibular joints. Learn more.

Convey the value of x-rays with ADA brochure

When a patient asks why radiographs are needed, the ADA has a brochure to express the reasons. “Dental X-Ray Exams: Answers to Common Questions” explains that finding and treating dental problems at an early stage can save time and money and prevent pain.

The handout assures patients of the safety of X-rays and shows how dental offices take steps to reduce radiation exposure. This six-panel brochure features new X-ray images and comes in packs of 50, with volume discounts available. 

Members can preview “Dental X-Ray Exams” online. To order, call 1-800-947-4746 or go to adacatalog.org. Readers who use the code 16402E before Jan. 22 can save 15 percent on all ADA Catalog products.


Free eBook on Exposure and Expectations

Managing dose in digital imaging is necessary to better understand how to bridge the gap between clinically valuable images and patient safety. In this eBook you will learn: how radiation is measured; how to determine the right dose; strategies for optimizing dose and not losing image quality. Click here for more information.


What is Specialty Scan?

This is one in a series of quarterly newsletters updating dentists on selected specialties in dentistry. Information presented is aggregated and summarized from previously published materials, each item attributed to its publication of origin. This issue of JADA Specialty Scan focuses on oral and maxillofacial radiology, the first in the series on this topic for 2016. Other Specialty Scan issues are devoted to endodontics, oral pathology, orthodontics, periodontics and prosthodontics. The ADA has engaged the specialty organizations in these areas as well as its own Science Institute and Division of Legal Affairs to assist with these newsletters. We welcome feedback on this and all Specialty Scan issues.

Editorial and Advertising Policies

Any statements of opinion or fact are those of the authors and do not necessarily reflect the views of the American Dental Association. Neither the ADA nor any of its subsidiaries have any financial interest in any products mentioned in this publication. Any reference to a product or service, whether in advertisements or otherwise, is not intended as an endorsement or as approval by the ADA or any of its affiliated organizations unless accompanied by an authorized statement that such approval or endorsement has been granted.

All matters pertaining to advertising should be addressed to the advertising sales manager, Sales and Marketing Department, American Dental Association, Publishing Division, 211 E. Chicago Ave., Chicago, IL 60611, 1-312-440-2740, fax 1-312-440-2550. All advertising appearing in ADA publications must comply with official published standards of the American Dental Association, a copy of which is available on request.