What you didn’t learn in dental school: Part 2 — crossbites

Little Jimmy, age eight (and a patient of yours since age five), doesn’t seem to have enough room for all his teeth. In fact, two of them appear to be in crossbite.

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Little Jimmy, age eight (and a patient of yours since age five), doesn’t seem to have enough room for all his teeth. In fact, two of them appear to be in crossbite. Could you explain to his parents why this is the case? Could you treat the problem?

The goal of appliance therapy is to provide the best, most economical care possible over the life of the patient — while providing the dentist the opportunity to address basic orthodontic problems like Jimmy’s, provide needed therapy, and make a good living.

What you need to know

Crossbites don’t go away on their own. Early treatment — in the primary and mixed dentition — is vital. Left untreated into permanent dentition, the worsening condition will not only require further orthodontic care, but may cause a host of different problems.

There are three basic types of crossbite: 1) simple anterior; 2) functional anterior (pseudo Class III); 3) skeletal anterior. Each is unique with its own specific diagnostic criteria.

Easiest to treat is the simple anterior crossbite. Common etiologic factors include: trauma to primary incisors with displacement of permanent tooth bud; delayed exfoliation of primary incisor with palatal deflection of erupting permanent incisor; supernumerary anterior teeth; odontomas; congenitally abnormal eruption patterns, and arch perimeter deficiencies.

Characteristics of a simple anterior crossbite

  • Only one or two teeth are involved.
  • Facial profile is normal in centric relation and occlusion.
  • Anterior posterior skeletal relationship is normal.
  • Mandible has a smooth arc of closure into an Angle Class I molar and cuspid relationship, with a coincident centric relation and centric occlusion.
  • Abnormal axial inclination of either maxillary or mandibular anterior teeth as they erupt.

What you need to learn

  • When to treat? As soon as the crossbite is recognized and as soon as you have a patient cooperative enough to treat — as young as age three.
  • How to treat? The absolute best treatment is to prevent the condition from ever occurring — via regular radiographic scans of the maxillary incisor region and careful management of severe arch perimeter deficiency.
  • Once a simple anterior crossbite exists, methods of treatment include the use of a variety of techniques such as biting on a tongue blade, placing a reverse stainless steel crown, adding an incline plane to the teeth involved, and dental appliances such as a Hawley retainer. The key: use a technique that is both comfortable and predictable.
  • Is there adequate space? One of the most common mistakes a beginner makes when trying to correct a crossbite is to try to move a tooth into position when there is not enough space to do so. Making sure there is adequate space may involve slenderizing primary cuspids, extracting primary cuspids, and/or expansion of the arches.
  • Always try to anticipate whether other anterior teeth will erupt into crossbite. If this is likely, you may want to postpone treatment to allow correction of the additional teeth at the same time with one appliance.
  • Appliances can only be effective when properly designed to adhere to the principles of retention, force application, and anchorage. Because spring pressure is applied to an inclined plane, the reaction tends to dislodge the appliance. Some form of retention must be placed near the spring via circumferential clasps placed on the deciduous canines or first permanent molars.
  • The position of an unerupted cuspid should be determined prior to proclining a lateral incisor which is in crossbite to ensure that the root of the incisor will not be forced against the crown of the canine and possibly damaged.
  • When to refer? Look closely at the list given above outlining the characteristics of a simple anterior crossbite. If the crossbite does not fit these criteria, odds are the crossbite is more complicated than it appears. If you’re a beginner or only interested in treating minor tooth movement, it is time to refer.

The average fee for basic anterior crossbite correction ranges from $700 to $1,200, and may eliminate the need for further orthodontic care later on (potential cost to adult patient: $3,000 to $6,000). By treating two patients a month, you can easily add $12,000 a year to your bottom line.

Anterior crossbite must be treated in the primary and mixed dentition. Every general dentist can do this and should be doing it. Supervised neglect — the default position for all too many dentists because they haven’t been trained and they have been taught to fear orthodontics — is not an option.

Dr. Rob Veis is CEO of the Appliance Therapy Group® (ATG). He can be reached through www.appliancetherapy.com or by calling (800) 423-3270

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