Q. My son has suffered from chronic mouth ulceration since the age of 2. In the last year he has been given a diagnosis of a benzoate allergy and placed on a strick benzoate free diet. He presently requires extensive orthadontic treatment which will require him wearing braces. However we have received a letter today from his consultant informing us that one of the cements used contains debenzoyl, which can degrade into benzoic acid. My son’s allegies have meant that he has not been free from ulceration at any point since the age of 5 and although when keeping strickly to the diet it does reduce the inflamation and ulceration, it never completely clears up. The orthodontist has suggested putting part of the brace on and then wait and see how Fraser copes with this. However, his oral specialist has suggested that invisalign may be a better way to treat my son. Another complication with my son’s condition is that the membrane in his mouth is extremely fragile and any slight knock or rubbing will result in further inflamation and ulceration. On speaking to my son’s orthadontist he has appeared ill-informed and uninterested in questions relating to treatments other than the normal train tracks. I would be grateful it you could provide me with any further information or advice that may help this on going issue with my son.,