Pacific Coast Society of Orthodontists Bulletin Spring 2013 - (Page 29)

SUMMARIES ANNUAL SESSION 3-D Image-Aided Treatment of Impacted and Transposed Teeth Presented by Sunil Kapila, DDS, MS, PhD, at the PCSO Annual Session, October 5, 2012. Summarized by Dr. Douglas Hom, PCSO Bulletin Southern Region Editor. W hat are the benefits, risks, and limitations of cone-beam computed tomography (CBCT)? What are the current protocols for CBCT use and image interpretation? What are the evidence-based indications for CBCT? And finally, does 3-D imaging help to optimize biomechanics for impacted and transposed teeth? Dr. Sunil Kapila addressed these questions and others during his presentation at the 2012 PCSO Annual Session in Monterey, CA. responsible for reporting any atypical findings the to patient and if necessary, recommend or refer for treatment.. Because of the high volume of data contained in CBCT scans, the current recommended protocol calls for both the orthodontist and an oral-maxillofacial radiologist to interpret the 3-D image. CBCT is not currently accepted by most clinicians for routine orthodontic records usage. The prevailing emphasis on evidence-based therapy in orthodontics leads one to question Dr. Kapila what is the best evidence-based use for CBCT today. In what situations will the information Prior to ordering a CBCT scan, the orthodontist should gathered from a CBCT scan likely alter the diagnosis consider a number of issues. What are the benefits, risks, and/or treatment plan in a significant number of cases? and limitations of CBCT? The most immediate benefit is According to Dr. Kapila, the only situation that currently that CBCT offers an accurate 3-D representation of anaqualifies under this strict definition is the impacted maxiltomic structures without the superimposition of structures lary canine. However, a continuous flow of research is seen in traditional 2-D radiographs. In the diagnosis and clarifying the protocols. Dr. Kapila expects that unerupttreatment planning of certain types of cases, this capabiled teeth, missing teeth, asymmetries, and anterior open ity offers distinct advantages over 2-D radiographs. These bite will also be identified as cases that will benefit from situations include localization of impacted teeth, quanCBCT. tification of skeletal discrepancies, and analysis of the Several presented cases demonstrated CBCT usage in temporomandibular joint and airway. assessing the positions of maxillary impacted canines in The two major risks involved with CBCT are higher rarelation to upper lateral incisors. Visualization of addiation dose (compared to 2-D) and the increased chance ditional features, such as dilacerated canine roots, was of missing significant findings. Related risks include the shown. Finally, a case was presented that demonstrated problem of over-diagnosis or the detection of false posihow CBCT could be used to optimize biomechanics in the tives. A large-view CBCT scan exposes the patient to two treatment of an impacted canine. In this case, the crown to six times the radiation of a normal orthodontic series. of the impacted canine was directly adjacent to the lateral In other words, a large-view scan is equivalent to 10 to 35 incisor root. To avoid iatrogenic root damage, the upper days of background radiation. (Background radiation is lateral incisor roots were first tipped mesially away from estimated at 2,400 microsieverts per year.) the impacted canine. Using the 3-D image, bracket position and direction of force were then determined in order The volume of data inherent to a 3-D image is expoto optimally erupt the canine. CBCT images can be an exnentially higher than that of a 2-D image. Because of cellent modality for communication with the oral surgeon this fact, the skill set for interpreting a 3-D image has in terms of specific instructions in bracket placement. been demonstrated to be significantly higher than that required to interpret a 2-D image. Thus, the orthodontist As the interpretation and usage of CBCT continues to must receive adequate training to develop this skill set. evolve, most certainly many other evidence-based uses The practitioner who orders a CBCT scan is considered will become apparent in the near future S SPRING 2013 • PCSO BULLETIN 29

Table of Contents for the Digital Edition of Pacific Coast Society of Orthodontists Bulletin Spring 2013

Dental Ethics
Save a Little and Invest a Lot
Plan for Ongoing Success
AAO Trustee's Report
PCSO Business
AAOF Report
Component Report
PCSO at a Glance
Dr. Terry McDonald Interviews Dr. Harry (Hap) Doughterty, Jr.
Case Report Pre-Treatment
Dr. John Ive
3-D Image-Aided Treatment of Impacted and Transposed Teeth
Controversies in Orthodontics
DIY Technology Upgrades on a DIY Budget
Accelerated Osteogenic Orthodontic (AOO) System -- Physiological Benefits and Increased Range of Movement
Case Report Post-Treatment
Pearls from Idaho: Holding 3-3 Retainers While Bonding

Pacific Coast Society of Orthodontists Bulletin Spring 2013