The oral cavity is a complex landscape, cavernous and full of irregular structures. Using a two-dimensional X-ray to map its variations can only reveal so much. That’s why a technological revolution that has made three-dimensional imaging of the teeth and jaws easier and safer has ushered in a transformation of practice in the dental clinic.
“Oral and maxillofacial imaging is a field that is changing rapidly with the advent of newer technologies,” says Mupparapu, who also holds a position in the oral medicine division of Penn’s Perelman School of Medicine. “Having used 3-D imaging for at least a decade, we now have documentation of many disorders that can be shared with students, residents and colleagues.”
The new text looks at diagnostic techniques and image interpretation strategies for oral and maxillofacial conditions, including temporomandibular joint disorders and other causes of orofacial pain, tumors and systemic diseases affecting the jaw. It is an educational tool for dental students and practitioners, helping to fill a gap in the literature as such texts had been “few and far between,” Mupparapu says.
Among the technologies detailed by the book are CT scans, which use computers to show multiplanar reconstructions of the body, essentially a three-dimensional picture. In recent years, CT technology has become specialized for imaging the oral cavity. A new technique, known as a cone beam CT, or CBCT, captures many images in a single pass. Though still delivering more radiation than a two-dimensional scan, the total radiation dosage of CBCT can be as much as 20-fold lower than a medical CT scan, or MDCT.
By giving clinicians a unique view of a complex suite of anatomical features, 3-D technology has also allowed certain dental specialties to blossom. In particular, implantology has greatly expanded since 3-D images have come into wider use. Implants are used to replace teeth that are damaged by trauma, decay or periodontal disease or to take the place of adult teeth that may be missing, sometimes due to a congenital condition.
“I’ve seen patients as young as 10 years old who never had permanent teeth and seen them successfully receive implants later on in life,” says Mupparapu.
Baby boomers are also taking advantage of the new dental implant technologies, as many find dental implants an attractive alternative to dentures.
Acquiring and reviewing CT images prior to implant surgery can allow practitioners to design and place implants avoiding nerves, sinuses and other vital structures in placing the teeth. Before the advent of CBCT, implants were being placed on a limited basis, using 2-D radiographs, but now the field has exploded, and success rates are considerably higher.
In addition, 3-D imaging is a boon to periodontists, who evaluate the supporting structures of teeth, and to orthodontists, who use it to more accurately visualize the shape and placement of teeth in the mouth and jaw. It also aids in diagnosing conditions that may manifest as dental pain, for example, problems with the temporomandibular joint.
“I’m training my dental students and residents to not only look at teeth in general but also the surrounding structures within head and neck so they understand common nasal, sinus, cervical vertebral and TMJ pathologies,” Mupparapu says. “As a result, I think they're becoming better dentists overall.”
One chapter of the new book details all the major developmental anomalies that can affect the oral and maxillofacial area, depicting these with more than 20 tables and 3-D images. Another focuses on periodontal conditions, or those that affect the gums and bone that supports the teeth, noting how CBCT enables practitioners to view a level of anatomical detail they never have before.
A chapter co-authored by Mupparapu and Christine Nadeau of Quebec’s Laval University also describes how PET, PET/CT and PET/MR techniques are coming into more common use in oral radiology to diagnose conditions such as osteonecrosis of the jaw, which can arise in women taking bisphosphonate drugs, used to prevent osteoporosis.
With increased availability of technology, Mupparapu notes that a major lesson he imparts to his trainees is that radiologic imaging, while incredibly informative, must be used with caution.
“We are concerned about the long-term effects of low-dose radiation,” he says.
“Selecting appropriate radiographs for each patient based on need is the smart thing to do,” he says.
Penn Dental Medicine has long been a leader in oral radiology — Mupparapu pointed to a classic text book on the subject by Penn faculty LeRoy Ennis, Harrison Berry and James Phillips first written in 1931 — and he feels strongly about his and Penn’s role in continuing that leadership in the service of patients.
“We’re in the midst of a revolution in dental radiology,” Mupparapu says. “I have big shoulders to stand on.”