This technique involves the daily placement of carbamide peroxide gel into a custom-
fitted tray of either the upper or the lower arch. As the name suggests, it is carried out
by the patient at home and is initially done on a daily basis.
Indications
(1) mild fluorosis;
(2) moderate fluorosis as an adjunct to hydrochloric acid-pumice microabrasion;
(3) yellowing of ageing.
Armamentarium
(1) upper impression and working model;
(2) soft mouthguard⎯avoiding the gingivae;
(3) 10% carbamide peroxide gel.
Technique
- Take an alginate impression of the arch to be treated and cast a working model in
stone. - Relieve the labial surfaces of the teeth by about 0.5 mm and make a soft, pull-
down, vacuum- formed splint as a mouthguard (533HFig. 10.5 (a)). The splint should be no
more than 2 mm in thickness and should not cover the gingivae. It is only a vehicle
for the bleaching gel and not intended to protect the gingivae. - Instruct the patient on how to floss their teeth thoroughly. Perform a full mouth
prophylaxis and instruct them how to apply the gel into the mouth-guard (534HFig. 10.5
(b)). - Note that the length of time the guard should be worn depends on the product used.
- Review about 2 weeks later to check that the patient is not experiencing any
sensitivity, and then at 6 weeks, by which time 80% of any colour change should have
occurred.
Carbamide peroxide gel (10%) breaks down in the mouth into 3% hydrogen peroxide
and 7% urea. Both urea and hydrogen peroxide have low molecular weights, which
allow them to diffuse rapidly through enamel and dentine and thus explains the
transient pulpal sensitivity occasionally experienced with home bleaching systems.
Pulpal histology with regard to these materials has not been assessed, but no clinical
significance has been attributed to the changes seen with 35% hydrogen peroxide over
75 years of usage, except where teeth have been overheated or traumatized. By
extrapolation, 3% hydrogen peroxide in the home systems should therefore be safe.
Although most carbamide peroxide materials contain trace amounts of phosphoric and
citric acids as stabilizers and preservatives, no indication of etching or a significant
change in the surface morphology of enamel has been demonstrated by scanning
electron microscopy analysis. There was early concern that bleaching solutions with a