Interceptive Treatment for the Class III Malocclusion
INTRODUCTION:
A developing Class 3 malocclusion is one of the most challenging problems confronting an orthodontic clinician. If left untreated the Class III malocclusion may worsen, with the majority of these patients ultimately requiring orthognathic surgery, as adults.
For this reason, I recommend early interceptive orthodontic treatment to reduce the percentage need for surgery. Unfortunately, when interceptive Class 3 treatment is initiated at the appropriate age, there is often a significant amount of time between the end of facemask treatment and the beginning of "definitive" orthodontics.
I have written this article in an attempt to clarify the correct treatment protocol for Class 3 patients and to suggest methods of retention during their continued period of facial growth.
A developing Class III malocclusion can present with maxillary skeletal retrusion, mandibular skeletal protrusion, or a combination of the two. In addition to these sagittal problems there may also be posterior and anterior crossbites present. Dental compensation, such as maxillary dentoalveolar protrusion and mandibular dentoalveolar retrusion tend to produce poor facial profiles with midface deficiencies often apparent.
The prevalence of Class III malocclusion is approximately 5% in the Caucasian population, rising to as much as 50% in the Japanese and Korean population.
TREATMENT OF THE CLASS III MALOCCLUSION:
Although traditional orthodontic treatment, for developing Class 3 malocclusion, focused on the mandible as the primary cause of the discrepancy, recent studies have suggested that 63% of the skeletal Class III malocclusions display maxillary retrusion. The majority of patients tend to exhibit maxillary hypoplasia in conjunction with a normal or mildly prognathic mandible.
Unfortunately, I see too many young patients, for a second opinion, who are told there is nothing the orthodontist can do but wait until their facial growth is complete and then work them up for orthognathic surgery. Yet the majority of surgical procedures to correct Class III malocclusion involve maxillary advancements! This suggests that the problem was never excessive mandibular growth, but rather a lack of development of the maxilla. Such problems may have been caused by nasal airway blockages, when the child was younger.
Orthodontic treatment for the Class III malocclusion can be defined into the following categories:
1. Growth modification involving maxillary expansion and protraction face mask therapy
2. Growth modification involving a chin cup to restrain mandibular growth, or
3. Waiting until growth has ceased, thereby, committing the patient to either dental camouflage treatment, or orthognathic surgery.
In my orthodontic practice, children exhibiting early signs of a Class III malocclusion are given priority for treatment. My current treatment approach involves protraction and development of the maxilla, but I do not use chin cups as I feel they have an adverse effect on the patient's temporomandibular joints.
Controversy currently exists as to the optimum time to commence Class III orthodontic treatment. Takada examined maxillary protraction therapy and reported that the pre-pubertal and mid-pubertal time frame is best, due to the maxilla's natural growth (stage C2-C3).
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A developing Class 3 malocclusion is one of the most challenging problems confronting an orthodontic clinician. If left untreated the Class III malocclusion may worsen, with the majority of these patients ultimately requiring orthognathic surgery, as adults.
For this reason, I recommend early interceptive orthodontic treatment to reduce the percentage need for surgery. Unfortunately, when interceptive Class 3 treatment is initiated at the appropriate age, there is often a significant amount of time between the end of facemask treatment and the beginning of "definitive" orthodontics.
I have written this article in an attempt to clarify the correct treatment protocol for Class 3 patients and to suggest methods of retention during their continued period of facial growth.
A developing Class III malocclusion can present with maxillary skeletal retrusion, mandibular skeletal protrusion, or a combination of the two. In addition to these sagittal problems there may also be posterior and anterior crossbites present. Dental compensation, such as maxillary dentoalveolar protrusion and mandibular dentoalveolar retrusion tend to produce poor facial profiles with midface deficiencies often apparent.
The prevalence of Class III malocclusion is approximately 5% in the Caucasian population, rising to as much as 50% in the Japanese and Korean population.
TREATMENT OF THE CLASS III MALOCCLUSION:
Although traditional orthodontic treatment, for developing Class 3 malocclusion, focused on the mandible as the primary cause of the discrepancy, recent studies have suggested that 63% of the skeletal Class III malocclusions display maxillary retrusion. The majority of patients tend to exhibit maxillary hypoplasia in conjunction with a normal or mildly prognathic mandible.
Unfortunately, I see too many young patients, for a second opinion, who are told there is nothing the orthodontist can do but wait until their facial growth is complete and then work them up for orthognathic surgery. Yet the majority of surgical procedures to correct Class III malocclusion involve maxillary advancements! This suggests that the problem was never excessive mandibular growth, but rather a lack of development of the maxilla. Such problems may have been caused by nasal airway blockages, when the child was younger.
Orthodontic treatment for the Class III malocclusion can be defined into the following categories:
1. Growth modification involving maxillary expansion and protraction face mask therapy
2. Growth modification involving a chin cup to restrain mandibular growth, or
3. Waiting until growth has ceased, thereby, committing the patient to either dental camouflage treatment, or orthognathic surgery.
In my orthodontic practice, children exhibiting early signs of a Class III malocclusion are given priority for treatment. My current treatment approach involves protraction and development of the maxilla, but I do not use chin cups as I feel they have an adverse effect on the patient's temporomandibular joints.
Controversy currently exists as to the optimum time to commence Class III orthodontic treatment. Takada examined maxillary protraction therapy and reported that the pre-pubertal and mid-pubertal time frame is best, due to the maxilla's natural growth (stage C2-C3).
VIEW FULL ARTICLE:
http://www.e-deneducation.com/articles/documents?layout=document&e_id=21
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