[Oradlist] Use of Panoramic X-Ray to Determine Position ofImpacted Maxillary Canines.

Wed Apr 21 02:10:32 PDT 2010

hi all.

see also this paper:

Swed Dent J. 2008;32(4):179-85.
Ectopic maxillary canines and root resorption of adjacent incisors. Does computed tomography (CT) influence decision-making by orthodontists?
Bjerklin K, Bondemark L.

Department of Orthodontics, Institute for Postgraduate Dental Education, Jönköping, Sweden. krister.bjerklin at lj.se

Abstract
The purpose of this investigation was to evaluate whether access to computed tomography (CT) influences orthodontists' decision-making about management of incisor root resorption due to ectopic maxillary canines. The study base comprised orthodontic specialists and active members of the Swedish Orthodontic Society: 182 orthodontists under 65 years of age, who had been registered specialists for at least one year and were providing specialist treatment for regular orthodontic patients. A questionnaire was sent out, comprising 8 questions about management and decision-making in cases of ectopic maxillary canines with root resorption of adjacent incisors and 7 questions about practice profile. The orthodontists were asked whether they altered their treatment decisions when CT was available as a diagnostic tool. The response rate was high, 86%. Sixty of the orthodontists had access to CT. Sixty-one percent of the 97 orthodontists without access to CT stated that, in cases with space deficiency, they seldom or never considered extraction of a lateral incisor with suspected root resorption if the resorption was not discernible on intra-oral or panoramic radiographs. It was evident that even in cases of root resorption of lateral incisors due to ectopic canines,the orthodontists' management decisions were not particularly influenced by availability of CT diagnostic data. In the extraction cases 55% of the orthodontists considered extraction of the affected incisor first when root resorption was severe, i.e. involving the pulp and 37% when the resorption reached half way to the pulp. In cases without space deficiency 82% preferred to extract these resorbed lateral incisors not until the resorption reached the pulp.

best regards

Ann Wenzel

  ----- Original Message ----- 
  From: Mike Spoon 
  To: Oral Radiology Discussion Group 
  Sent: Wednesday, April 21, 2010 12:52 AM
  Subject: Re: [Oradlist] Use of Panoramic X-Ray to Determine Position ofImpacted Maxillary Canines.

  3D information is absolutely essential from an orthodontic standpoint. In the past we have taken multiple views, oftentimes resulting in the same ionizing dosage as a CBCT, and still we had to use a Gestalt methodology to arrive at a best estimate. CBCT eliminates the quesswork.

  3D information is important for assessing root recession on the lingual of the incisors or bicuspids that may display as a perfectly normal profile on a panoramic radiograph. 3D information, including the ability to measure root length accurately, is also necessary for calculating vectors and planning the mechanics of tooth movement. As you are pulling the crown down, the root is (generally speaking) rotating in the opposite direction. Also, it is helpful to know if there is a canine rotation you're going to have to deal with once the tooth emerges. Have you created enough clearance to be able to upright and move the tooth into position? Do the maxillary sinuses intrudes in the area where you need to move the root? I've seen canines lingual to the adjacent lateral and buccal to the central roots. How do you sort that out with 20th century imaging techniques?  I could probably come up with the few more reasons if you like.

  Michael E. Spoon, DDS
  Orthodontist

  On Apr 20, 2010, at 6:15 PM, Asma Al-Ekrish wrote:

    The question arises: How much detailed info do orthodontists need regarding the relationship of an impacted canine to the adjacent teeth. Is it sufficient for them to know whether the tooth is buccal or lingual to the adjacent teeth, along with the vertical angle of impaction? Or does additional information obtained by 3-D imaging (such as the distance between the impacted tooth and adjacent teeth and the horizontal angle of impaction) improve the diagnostic and therapeutic outcome for orthodontic patients? We will need the input of orthodontists in this matter.

    On Wed, Apr 21, 2010 at 12:02 AM, Allan Abuabara <allan.abuabara at gmail.com> wrote:

      Hello All,

      I read this recent and interesting manuscript and I want to share with you.
      Best regards.

      Allan Abuabara.

      J Oral Maxillofac Surg. 2010 Feb 4. [Epub ahead of print]

      Use of Panoramic X-Ray to Determine Position of Impacted Maxillary Canines.
      Katsnelson A, Flick WG, Susarla S, Tartakovsky JV, Miloro M.

      Resident, Department of Oral and Maxillofacial Surgery, Massachusetts General Hospital, Boston, MA.

      Abstract
      PURPOSE: To evaluate the position of impacted maxillary canines in the alveolus using panoramic radiographs. MATERIALS AND METHODS: The present study was a retrospective chart review of 102 patients with 130 impacted maxillary canines from the University of Illinois at Chicago College of Dentistry and private practice. Of the 130 impacted maxillary canines, 59 were impacted buccally and 71 were impacted palatally. The inclination of the impacted maxillary canines to a horizontal line from the mesiobuccal cusps of the maxillary molars was measured. We used these measurements to predict the position of the tooth and correlate this prediction with the actual approach used during surgery. RESULTS: The mean angulation of the buccally impacted maxillary canines was 75.1 degrees +/- 18.2 degrees (range, 8 degrees to 111 degrees ). The mean angulation of the palatally impacted maxillary canines was 51.3 degrees +/- 15.3 degrees (range, 12 degrees to 91 degrees ). The mean difference between the angulation of the impacted maxillary canines as measured on the panoramic radiographs was statistically significant (P < .001). >From a receiver-operator characteristic curve and using a logistic regression model, impactions greater than 65 degrees were 26.6 times more likely to be buccally impacted maxillary canines (P < .001). CONCLUSIONS: Panoramic radiographs are useful for predicting the location of impacted maxillary canines and the subsequent surgical approach required for exposure and orthodontic appliance attachment when computed tomography is unavailable or unnecessary otherwise. The use of panoramic radiographs for determing impacted maxillary canine position has a high sensitivity and specificity, with angulations greater than 65 degrees associated with buccal impactions. Copyright © 2010 American Association of Oral and Maxillofacial Surgeons. All rights reserved.

      -- 
      Allan

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    -- 
    Asma'a Al-Ekrish, MDS
    Lecturer, OMFR
    King Saud University
    Riyadh, Saudi Arabia

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