I assume the papers you are referring to are a Separation Agreement rather than court documents signed by a judge. If your agreement does not spell out exactly which items are necessary (and it probably does not, as the list could go on and on), the definition will be open to interpretation. If you and she can not eventually agree on which things are necessary, you will ultimately end up in front of a judge, asking him to decide for you. Since this will be expensive (more than the cost of the braces, for example) and time-consuming, it would be best if you and the ex could agree.
The basic rules for contract interpretation involve the use of common sense. In your case, if an orthodontist thinks braces are necessary, chances are a judge is going to believe they are necessary. Eyeglasses and ADD medication sound similarly important. Acne medication, perhaps less so.
Erik L. Mazzone
The Rosen Law Firm
4101 Lake Boone Trail, Suite 200
Raleigh, North Carolina 27607
The response posted above is based upon the limited factual information made available and is not intended as a full and complete response to the question. The only reliable manner to obtain complete and adequate legal advice is to consult with an attorney, fully explain your situation, and allow the attorney sufficient opportunity to research the applicable law and facts required to render an accurate opinion. The basic information provided above is intended as a public service but a full discussion with an attorney should be undertaken before taking any action.