Sunday, January 6, 2013

Case of the Month: January 2013

The following case will demonstrate the effectiveness of early orthodontic intervention to address an ectopically erupting tooth (a tooth erupting in the wrong direction or location) followed by the use of pre-molar extractions during comprehensive treatment to alleviate severe crowding.

The patient presented to the office at the age of 9 having been sent by her pediatric dentist due to a mandibular incisor erupting ectopically.

 As you can see above, the lower right lateral incisor erupted backwards in the dental arch, while the primary (baby) incisor (yellow X) that should have been lost was not.  This is obviously a problem because the canine and first pre-molar on that side would be blocked from erupting in the future.  She was sent back to her pediatric dentist to remove the retained primary incisor and limited braces on the front four incisors was initiated to tip the ectopic tooth into the correct position.  Because the patient was in the mixed dentition stage (half primary teeth/half permanent teeth), we call any orthodontic treatment at this time early or interceptive because we are essentially ensuring that a normal eruption process can occur.  Other common early or interceptive treatments include maxillary expansion and various types of headgear if a patient has a large enough jaw growth discrepancy. 

The total treatment time for the interceptive treatment was 7 months and the picture below shows the lower incisors in better position.

We continued to monitor the patient's tooth eruption pattern periodically over the next two years and comprehensive orthodontic treatment (full braces once all permanent teeth are in) was initiated at age 12.  When the patient returned almost ready for her comprehensive treatment, she had severe crowding due to a large tooth size/jaw size discrepancy and the decision was made to extract all of the permanent first pre-molars.  Orthodontists try to not have to extract permanent teeth, but the lower jaw limits our ability to expand because the jaw itself does not expand like the upper jaw because it does not have a growth suture in the midline and we also have to be careful not to push the teeth too far forward when aligning them and cause gingival recession. 

 The panoramic radiograph above shows the crowding issues, especially in the lower jaw where some of the canines and pre-molars don't have enough space to erupt.  A referral to her dentist was made to extract the first pre-molars and she returned in 6 months after the remaining teeth erupted to begin her comprehensive treatment.  The pictures below show how she presented at that time.

We then proceeded to place full braces on both arches.  After aligning and leveling each arch, the remaining extraction space needed to be closed.  The patient did a great job wearing rubber bands for us and otherwise did not need any other kinds of appliances.  The pictures below show the nice finish with excellent alignment, great esthetics and all teeth positioned well within their bony housing for long-term good periodontal health.

The total treatment time for phase II or her comprehensive treatment was 20 months, which is pretty typical for extraction cases.  If you look carefully, you can see that we are missing all of the first pre-molars, but no one would ever be able to tell.  Many people you know may have been effectively treated with extractions by their orthodontist.  As I stated earlier, we only extract when we absolutely have to (about 10% of cases in my practice), but extraction cases can work out very nicely when the proper diagnosis and treatment plan is followed.

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