ENGLISH ASSIGNMENT“UNDERBITE”

CREATED BY:

HESTI RAHAYU 1110070110039

LECTURER:

1. Dra Siti Zaura2. Yulianita S,S3. Primi Ovarianti M.pd

FACULTY OF DENTISTRY

BAITURRAHMAH UNIVERSITY

PADANG 2014

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Case:

The 14th years old girls , she had a severe discrepancy between her upper and lower jaws.

Analysis of her xrays showed that the discrepancy was mostly due to the relative size of her

lower jaw (her lower jaw was too large relative to her upper jaw). When there is a discrepancy

between the size and/or positions of the upper and lower jaws, the teeth ususally try to

compensate for this. If the lower jaw is in front of the upper jaw, usually you see that the upper

teeth are flared foward in an attempt to meet the lower teeth, and the lower teeth are leaned in, in

an attempt to meet the upper teeth. If the upper teeth are flared, you would expect to see spaces

between them, since as they flare out this moves them onto a larger perimeter and there is more

space for the teeth. If the lower teeth are leaned inward, you would expect them to be crowded,

since moving them inward places them on a smaller perimeter and they therefore have less

available space.

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Her upper side teeth were also flared out to compensate for the fact that her arch forms were

displaced from their normal relationships. The animation below depicts this (you must have

animated gifs turned on in your browser's preferences to view the animation). A change in the

front to back relationships of the upper and lower arch forms affects the width relationships as

well:

I considered the following options for her treatment:

Option 1. Use braces alone without the removal of any teeth. This option would require that I

further compensate her teeth for the jaw discrepancy.To accomplish this, I would need to bring

all of her top teeth forward to the extent indicated by the red arrows above, move her bottom

teeth back that amount, or do some combination of moving her upper teeth forward and her

lower teeth back. This option would not address her lower jaw position which is the basic cause

of her teeth not fitting together. It is not possible to move her lower teeth back without the

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removal of any teeth, so this option would necessitate making all of the correction by moving her

upper teeth forward. Since they are already leaned forward, I would need to lean them forward to

such an extent to meet the bottom teeth that the upper teeth would be moved off the bone

(essentially extracting them) -- not a good idea. Option 1 is not a good one.

Option 2. Use braces alone with removal of teeth. this still does not address the basic cause of

her problem, but we did consider extracting a tooth on each side to create enough space to move

her lower teeth back. Since the bone was thin on the inside surface of her lower front teeth,

leaning them inward would have made them more prone to periodontal (gum) problems. In

addition, any treatment plan involving extractions and further compensating her teeth would

accentuate her chin and leave her upper front teeth leaned out - both of which we decided were

undesirable. We therefore decided against option 2.

Option 3. Braces in conjuction with jaw surgery (orthognathic surgery). Since this option

addressed the true cause of her problem and met the esthetic objectives that we had, we

proceeded with this option.

Treatment:

Since her teeth had compensated for her jaw discrepancy, and since the jaw surgery would

correct the jaw discrepancy, her initial treatment would involve putting her teeth in the proper

positions in her jaw bones (this is called "decompensating" the teeth). This required constricting

the width of her upper arch and leaning in her upper front teeth. The lower spaces were closed by

leaning her front teeth in. The space between her upper front teeth was closed before surgery.

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This pre-surgical stage took 16 visits (scheduled 1 month apart). She then had jaw surgery which

involved moving her lower jaw back to fit into proper position with her upper jaw (subcondylar

osteotomy). Post-surgical orthodontic treatment involved fine-tuning the coordination of the

widths of her upper and lower arches, and trying to correct her midlines 100%.

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