Two-Phase Mixed Dentition vs. Comprehensive Treatment in Permanent Dentition

Edited by Dr. Michael A. Sales

Question: An 8-year, 4-month-old female patient with brachycephalic features, deep bite (almost, but not quite, palatal contact), 8mm overjet, lip contact in rest, acceptable appearance, full CL II molar and cuspid relationship, and no arch-length deficiency shows up at your office for an initial evaluation.

She is average in dental and skeletal development. The appointment was made as a result of her dentist’s suggestion. Patient and parents are completely receptive to your point of view and are not pushing for one plan over another. What do you recommend?

Dr. Bernard Chang

This case scenario obviously brings up the question of two-phase early treatment versus waiting for comprehensive treatment in the permanent dentition.

The following are some of the many factors I consider prior to determining whether a patient can benefit from early treatment.

1. Will the overall treatment become more difficult if early treatment is not performed?

2. Will the end result be less than ideal or less stable without early treatment?

3. Will early treatment significantly improve the patient’s dental and facial esthetics?

4. Is there a skeletal discrepancy (A-P or transverse)?

5. Are extractions necessary?

My recommendation for this patient, based upon the information available, is to do no treatment at this time. Although the patient has a severe malocclusion, chances are that the Class II can be corrected successfully with comprehensive treatment in the permanent dentition.

The fact that she has brachycephalic features indicates that her natural horizontal growth pattern combined with traditional Class II correction mechanics (elastics, headgear, springs, Herbst, etc.) will correct her malocclusion without extractions or surgery.

Primarily, her problem seems to be a dental discrepancy based on the fact that she has an acceptable appearance and lip closure.

My personal preference is to treat this patient when her 2nd primary molars are ready to exfoliate. By doing so, the first permanent molar can be held distally and the lower molar can erupt mesially into the leeway space.

This type of patient would be placed on a six-month recall in my office and I would recommend a panoramic x-ray to check for proper eruption.

Dr. Kami Hoss

I work with my wife, who is a pediatric dentist. As a result, I do see and treat many early treatment/Phase I cases. I truly believe in early treatment and, therefore, convey my bias fairly effectively to parents.

My three goals for Phase I are:

1. Habit correction

2. Skeletal correction

3. Space correction

In this case we are obviously dealing with a major skeletal discrepancy. My rationale for addressing this problem now, versus waiting for all of the permanent teeth to erupt, echoes some of the AAO’s reasoning: lower the risk of trauma from protruded upper incisors, improve aesthetics and self-esteem, simplify and/or shorten treatment time for later corrective orthodontics, and, take advantage of greater cooperation typical of a younger age group.

Specifically for this patient, in addition to my clinical evaluation, I would gather all necessary diagnostic records to determine the etiology of the skeletal disharmony.

If the maxilla were the major component of the problem, I would probably use a combination of a headgear and a biteplate.

If the mandible were the major cause of the discrepancy, I would probably use a functional appliance (typically TwinBlock in these cases).

And, if both jaws have contributed to the disharmony, I might use headgear and Twin Block simultaneously.

Because I treat many cases in two phases, I establish very clear goals and objectives for each phase. In lay terms, I tell the parents that during Phase I, "We get the jaws in the right place," and during Phase II, "We get the teeth in the right place."

I also try very hard not to extend treatment time for Phase I beyond the estimated time (usually 12 months). It’s very important that patients do not feel that "they’ve been in braces for five years."

Editor's Comment: Dr. Michael Sales

Let me take this opportunity to thank Drs. Hoss and Chang for their contributions to the PCSO Bulletin the past four issues. Their input was enlightening and the diversity of thought provoked each reader to consider their own positions on the various subjects explored.

It is quite apparent that these young members will continue to examine and challenge the orthodontic issues that confront each of us on a daily basis.

As our panelists approached the entire subject of early treatment in their responses, I will comment in kind.

Early treatment decisions continue to challenge our profession. The wide span of thinking on this subject forces us to recognize the need to refine criteria for case selection as well as to substantiate the rationale for any particular case.

Obviously, there is no choice but to accept full permanent dentition treatment as a starting point when the patient is not referred into our office until that time.

But, is the corollary true? Should we begin orthodontic treatment because the patient happened to be seen at an early stage of dental development? While there is some evidence to support the value of early intervention when certain circumstances exist, early treatment for many cases seems to be applied in a more whimsical fashion.

For instance, what combination of arch length deficiency, stage of dental development, and skeletal pattern actually define the best time to intercede? Would an ALD case first seen at age seven treat out any differently three or four years later? If so, would the outcome be less desirable, the same or, perhaps, better?

The multi-variate etiologies and numerous variables associated with each patient and practice situation makes generalizations difficult and often inappropriate.

One area of concern for me has been the often heard statement that aside from time and cost there is little to lose and potentially much to gain with early intervention.

In fact, I have seen many complications from ill- conceived early treatment. Impacted second molars and inordinately prolonged treatment times, resulting in abandonment of care prior to attaining the best result, are two examples.

Failure to recognize that a non- extraction plan or non-surgical plan is just not going to provide a satisfying result are other instances. This can culminate in years of unnecessary treatment with the patient sometimes ultimately refusing to accept a more desirable plan when it is finally offered.

The fact that large numbers of practitioners and patients are pleased with the outcomes achieved treating similar cases in dissimilar ways must tell us something. But what?

Early in our careers, we practice relative to belief systems instilled during our residencies. If we join an existing practice it is likely that treatment will be greatly influenced by the methods employed in that office.

With the passage of time and accumulation of experience, we either reenforce our previously held views or we may determine that a change in direction is necessary.

For now, there appears to be a consensus on at least a few early treatment indicators. Specifically, unilateral cross bites, anterior cross bites, large overjet cases with lip incompetency, deep bites with soft tissue impingement, open bites, severe incisor rotations, some craniofacial cases, and individuals with a psychologic need created by a cosmetic concern.

And of course, serial extraction becomes an entire issue unto itself. I believe that situations involving CL II skeletal relations, crowding, and growth modification still require greater understanding and more study.

In addition, and of particular interest, are the areas of long-term periodontal health and the ever-lingering question of stability.

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