Proposed clinical skeletal transverse measurement technique

Dr. John L. Hayes explores the benefits and limitations of a clinical palpation technique

Educational aims and objectives
The aim of this article is to present a clinical palpation technique that can be used to evaluate a patient’s skeletal transverse dimension before, during, and after rapid palatal expansion (RPE).

Expected outcomes
Correctly answering the quiz questions is worth 2 hours of CE, will demonstrate the reader can:

1. describe a new clinical palpation technique in an attempt to evaluate a patient’s skeletal transverse dimension for possible maxillary deficiency and also to follow RPE treatment progress.
2. discuss the advantages and disadvantages of the palpation technique.
3. explain how root prominence of the abutment teeth can simultaneously be monitored.
4. discuss how early warning of failure of RPE maxillary midline suture separation may be noticed by increased root prominence of the abutment teeth and also by increased inclination of abutment teeth. Click here to take the quiz

Abstract
This article proposes a clinical palpation technique in an attempt to evaluate a patient’s skeletal transverse dimension before, during, and after rapid palatal expansion (RPE). The limitations of palpation are important; when available, the skeletal measurement of dental casts is preferable.

Nevertheless, palpation has advantages that measurement of dental casts does not have. It is important to know whether RPE is effectively improving the skeletal transverse or if it is not changing appreciably. Palpation can, with practice, allow enough discernment to allow that determination.

We should understand that failure of the maxillary suture to respond to RPE activation could be creating untoward inclination of the posterior abutment teeth with possible problematic implications. An orthodontist would want to know this as soon as possible.

It may not be convenient or recommended to obtain dental casts or films at each RPE progress visit to measure skeletal progress versus added dental inclination. Palpation requires only a few seconds to gain such valuable information.

Introduction
Palpation, in general, is a routine part of medical physical exams and is helpful in the diagnosis of many medical conditions. Palpation is also routinely used in dentistry for patient head, neck, and temporomandibular (TMJ) exams. Palpation of a dental patient’s skeletal transverse situation could easily be part of routine dental exams to determine the presence or absence of a skeletal transverse deficient maxilla. A deficient maxilla may be a progenitor of other potential problems.¹

This article proposes a new clinical palpation technique in an attempt to evaluate a patient’s skeletal transverse dimension for possible maxillary deficiency and also to follow RPE treatment progress. The limitations of palpation are important; when available, the measurement of dental casts is preferable for improved accuracy.¹

Nevertheless, palpation has advantages that measurement of dental casts does not have. It should be important to know during RPE whether the skeletal transverse is changing. It is important to know also to what degree the proclination of posterior abutment teeth may be increasing, as the dental expansion part of RPE tends to be transitory. Palpation can, with practice, allow enough discernment to allow determination that skeletal expansion is occurring.

We should understand that failure of the maxillary suture to respond to RPE activation could create untoward inclination of the posterior teeth with possible problematic implications. This possibility can be quickly diagnosed by way of palpation.¹

Materials and methods
One’s index fingers are used to palpate the buccal aspects of the arches. The fingers are aligned in a position that may look like a “caliper” (Figure 1) and placed at the locations indicated (Figures 2, 5, and 6)—the relative transverse dimension of maxilla versus mandible can then be approximated by palpation. Note that fingertips are placed adjacent to the first molars at the level where the roots joint the crown—which would be close to the center of rotation of the molars—a position that approximates the lateral border of the apical base of bone, although more incisal.^2,3

While holding the index fingers “fixed” and parallel, the “finger calipers” can be moved between the Mx-Mx points (Figures 2-4) and points that shall be called Md-Md on the mandible (Figures 2, 5 and 6) to observe and feel the relative jaw “apical bases” at their buccal aspects. Class II patients should be asked to position their mandible into a Class I skeletal position prior to measurement.

How should the maxillary and mandibular arches, in harmony, feel by palpation? One goal could be for the arches to feel similar in width at Mx-Mx versus Md-Md. Another goal could be that the maxilla should feel slightly wider than the mandible. If the maxilla were to feel narrower than the mandible, a deficient maxilla could then be diagnosed. New, proposed transverse skeletal criteria have been discussed.⁴

With a particular transverse harmony goal in mind, an orthodontist may advise continued RPE activation or not. The RPE treatment progress can be monitored at each recall visit by the finger-caliper technique until the treatment goal is reached by palpation. The root prominence of the abutment teeth can simultaneously be monitored. Increased root prominence of abutment teeth could indicate that the palatal suture is unresponsive.

Discussion
With practice, the finger-caliper technique should give one confidence with bi-lateral jaw measurements. The location of Mx-Mx points is identical to the Mx-Mx location sought for by some orthodontists using posteroanterior (PA) films.³ The location of Md-Md may take more time to master than approximation of the Mx-Mx measurement. It is possible to palpate for Md-Md too far apically—where, in some instances, the body of the mandible bulges laterally. That error would tend to overstate the desired Mx-Mx dimension.

Finger-caliper measurements have all the same problems, discussed previously, with any measurement technique taken adjacent or near the apical base.³ However, the advantages of the finger-caliper technique are numerous. Increased dental inclination without skeletal changes, noted by palpation, can give early warning of failure of RPE maxillary midline suture separation. Increased root prominence of abutment teeth, with RPE activation can also be noticed with palpation.

Conclusions
1.    The finger-caliper technique can be used to approximate the skeletal transverse situation adjacent to the apical bases during an initial exam visit, and later during activation of RPE.
2.    Palpation measurements should be attempted with the Class II patient holding his/her jaw in a Class I position.
3.    Palpation of a patient’s transverse skeletal situation could easily be part of a routine dental exam to determine the presence or absence of a skeletal deficient maxilla, which can be a progenitor of other potential problems.
4.    A working diagnosis of maxillary deficiency by palpation can be confirmed later with measurement of dental casts.
5.    Early warning of failure of RPE maxillary midline suture separation may be noticed by increased root prominence of the abutment teeth and also by increased inclination of abutment teeth.
6.    The limitations of palpation are important; when available, the measurement of dental casts is preferable for more accuracy.

John L. Hayes, DMD, MBA, received his dental degree from the Boston University H.M. Goldman School of Graduate Dentistry and his orthodontic certificate from the University of Pennsylvania School of Dental Medicine, Orthodontic Department, where he is a Clinical Associate. Dr. Hayes is on the Editorial Review Board of the American Journal of Orthodontics and Dentofacial Orthopedics, as well as Orthodontic Practice US. He continues to research and lecture on the advantages of early interceptive treatment and on the etiology of malocclusions. He is board certified by the ABO. He has been the secretary of his local dental society since 1986. Dr. Hayes is in private practice in Williamsport, PA, with his wife, Sharon, who is also an orthodontist. He can be reached at This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

References

1.    Hayes JL (March, 2003) A clinical approach to identify transverse discrepancies. Presentation to the Pennsylvania Association of Orthodontists, Philadelphia.
2.    Lundstrom AF (1923) Malocclusion of the Teeth Regarded as a Problem in the Connection with the Apical Base. Svensk Tandlakare Tidskrift.
3.    Hayes JL (2010) In search of improved skeletal transverse diagnosis. Part 1: traditional measurement techniques. Orthodontic Practice US 1(3);34-39.
4.    Hayes JL (2010) In search of improved skeletal transverse disgnosis. Part 2: A new measurement technique used on 114 consecutive untreated patients. Orthodontic Practice US 1(4);34-39.