Pacific Coast Society of Orthodontists Bulletin Winter 2014 - (Page 49)

SUMMARY ANNUAL SESSION ROOT RESORPTION Presented by Dr. Glenn Sameshima at the PSCO Annual Session, October 4, 2014. Summarized by Dr. Bruce P. Hawley, PCSO Bulletin Northern Region Editor. O rthodontically related root resorption is technically referred to as external apical root resorption (EARR). Generally, resorption of dental root surfaces is reversible, except at the root apex. There is really no ideal orthodontic force, and there appear to be individDr. Sameshima ual variations in biological tolerance to orthodontic forces. However, light forces seem to be more biologically compatible than heavy forces. The greatest amount of root resorption occurs on maxillary incisors, with the maxillary lateral incisors showing a greater susceptibility than the maxillary central incisors. In rank order, these are followed by maxillary canines, mandibular incisors, the mesiobuccal root of maxillary first molars, second premolars, and first premolars. DIAGNOSTIC and TREATMENT RISK FACTORS Genetics and individual predisposition may be the best predictors of EARR. Of course, there is a wide variation within the general population. With respect to ethnicity, root resorption may be higher in the Hispanic population. Adults may or may not show a greater incidence than younger patients. Odd root shape and long-rooted teeth appear to have an association. While there is no clear evidence, there could be a relation with bone diseases or endocrine considerations (beware of patients with Turner's syndrome). Extended orthodontic treatment time is definitely associated with increased resorption. Apical displacement by force and direction, including apical movement towards the palate, is also related. Increases in retraction distance, such as large overjet reduction, show progressively more resorption. The use of TADs has also been noted to increase EARR, including major intrusions. While we do not know why, orthodontic extrusions can also result in resorption. WINTER 2014 * PCSO BULLETIN With respect to decreasing risk, endodontically treated teeth do not show EARR. A small percentage of incomplete roots - that is, those with "immature" apices - show stunted root ends. Periapical X-rays are superior to panoramic X-rays for visualizing root shortening. CBCT demonstrates resorption at the root apex with intrusion, and at the apex in the direction of labial tooth movement. There is no significant difference between straight wire and self-ligating appliances. Little to no EARR is seen with orthodontic aligners or removable appliances. While it can occur, especially with greater tooth movements, there tends to be much less lateral tooth movement with this treatment as compared with fixed appliance therapy. CLINICAL MANAGEMENT of EARR Patients with short roots need to maintain good oral hygiene. If significant resorption is noted during active treatment, one should halt active orthodontics - preferably with passive archwires - for at least four months. You can then take progress periapicals or a panoramic X-ray and proceed with active orthodontics if it looks safe to do so. In more extreme situations, debanding is also an option, as EARR stops with the cessation of active tooth movement. Be sure to inform the patient and, as appropriate, the patient's dentist. Clarify that the affected teeth are not in hyperocclusion (and equilibrate if necessary). LONG-TERM CONSIDERATIONS Most periodontists feel that it is not necessary to splint teeth with pronounced resorption and mobility, as they will usually firm up. The good news for orthodontists and our patients is that the long-term prognosis for teeth significantly affected by EARR is typically positive, with the incidence of tooth loss or periodontal disease not increased by short or shortened roots. In some cases, there may be a slight comparative increase in tooth mobility. S 49

Table of Contents for the Digital Edition of Pacific Coast Society of Orthodontists Bulletin Winter 2014

A Clear Message and a Clear Plan
So Much to Share and Celebrate!
Facebook and Orthodontic Practice Marketing
Component Reports
AAOF Report
PCSO At a Glance
Poor Posture = Back and Neck Pain
Resident Spotlight: Roseman University College of Dental Medicine, Postgraduate Orthodontic Program
Younger Member Spotlight: Dr. Mahbod Rashidi
The University of the Pacific’s Arthur A. Dugoni School of Dentistry
Dr. Terry McDonald Interviews Dr. Glenn Sameshima
New Technology for a New Office: Cost-Effective and Space-Saving
Case Report Pre-Treatment
Dr. Frank Beglin, PCSO President 2014-2015
Helping Autistic and Special Needs Children
Organization and Innovation are Intertwined
Patient Service: Thinking Outside the Box
Clinical Applications of TADs and Outcome Evaluations with 3-D CBCT Superimposition
Root Resorption
Tips and Tricks from the Trenches
Case Report Post-Treatment
Diastema-Closing Appliance
Dr. David Thomas Lawless

Pacific Coast Society of Orthodontists Bulletin Winter 2014