Maxillary Vertex Occlusal
My patient presented with unerupted maxillary canines and a routine panoramic film revealed these to be impacted. I supplemented the examination with a standard maxillary occlusal film. From these 2 films, am I able to determine if the canines are palatal or lingual to the plane of the arch?
While the panoramic and maxillary standard occlusal reveal the maxillary canines to be impacted, it fails to determine their bucco-lingual relationship to the plane of the arch.
Since you seem to be familiar with the maxillary standard occlusal technique, I would suggest you do a Vertex Occlusal Film. The vertex occlusal film is a modified technique from the standard maxillary occlusal which is specifically helpful in determining the relationship of impacted teeth to the maxillary plane of the arch. The technique is described below.
TECHNIQUE for the MAXILLARY VERTEX OCCLUSAL
The patient is oriented with the occlusal plane parallel to the floor and the occlusal film gently held in the patient’s mouth with the teeth. The central ray (C.R.) is directed through the top of the head at the point on the film where the mid-sagittal plane and an imaginary line from the lingual of the first molars would intersect. The central ray should be directed at a vertical angle of +110 degrees.
Relative to a periapical exposure, assuming constant kVp and mA exposure, time is increased approximately 6 times. Alternatively, to lessen the increase in exposure time, the kVp may be increased and/or the focal film distance may be decreased by removing the cone on the x-ray head.
In this case a maxillary vertex occlusal was exposed and revealed the crowns of 13 & 23 to be palatal to the 12 & 22.
The author wishes to acknowledge Dr. Bruce Freeman (A Toronto Orthodontist) who kindly donated the radiographs included in this article.
Dr. Martin Bourgeois is Oral Health’s Board member, Radiography. He can be contacted at www.oralradiology.com
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