| case report Tooth whitening and orthodontics: The icing on the cake By Dr Yassine Harichane, Canada Tooth whitening is a therapeutic procedure that pro- vides the final touch to orthodontic treatment. The objectives in orthodontics are both functional—restore masticatory function, swallowing, breathing and phona- tion—and aesthetic—balance and harmonise the face, and improve the smile. To achieve the last goal, various criteria are taken into account: tooth alignment, shade and shape, and even the shape of the lips. All these parameters are important; however, the most visible aspect of the smile is the dental shade. One can restore function, correct an occlusal dysfunction, close a dias- tema or even inject dermal fillers, but if the teeth are left yellowish, the smile remains unattractive. Tooth whitening is a therapeutic solution that restores the natural lustre of the teeth by removing organic stains, which means it is not tooth bleaching. For the orthodontist, there are only advantages. It is easy to perform, non-invasive, requires no anaesthesia and produces no irreversible destruc- tion of the tooth. This procedure is rewarding for the dental team, since the dental assistant can be involved in all steps of the process. It is suitable for the major- ity of patients. Tooth whitening is a cost-effective tech- nique that requires little material and time, and is efficient if the practitioner is rigorous. Finally, the main concern for patients, it is painless. How does it work? The enamel shade can change because of tobacco stains, food or trauma, for instance. The protocol involves the application of a tooth whitening product, such as hydrogen peroxide, carbamide peroxide or sodium per- borate. The last one must be avoided, since it is classified as repro-toxic. The first two are efficient and safe. The difference between them lies in the fact that hydrogen peroxide is the active ingredient and carbamide perox- ide is a derivative that degrades into hydrogen peroxide. This release is progressive and slow. This process is suit- able when the practitioner desires a soft and progressive effect. Regarding dosage, the percentage provided by the manufacturer reflects the concentration: 1% of hydro- gen peroxide is equivalent to 3% of carbamide peroxide. In Europe, the maximum limit for vital teeth is 6% hydro- gen peroxide or 18% carbamide peroxide. What are the indications? There are two main indications: intrinsic post- eruptive stains and extrinsic stains. Intrinsic post-eruptive stains concern mostly clinical cases involving pulp necrosis (trauma, endodontic treatment, endodontic calcification). Among extrinsic stains, there are tobacco stains, discol- oration due to ageing and physiological stains. It is in the last category to which most post-orthodontic treatment applies. Indeed, tooth whitening will allow beautiful finish- ing by complimenting the orthodontic result. The patient will notice the difference—the teeth are well-aligned and whiter—and forget that the orthodontic process took so much time, as the tooth whitening needs just a few days. The treatment is of benefit to the practice too, since the orthodontist not only restores the function, but improves the aesthetic outcome painlessly too. How to perform tooth whitening The different techniques will be demonstrated through clinical cases. In the first case, the patient was being treated with a lingual appliance (Fig. 1) and wished to whiten her teeth. In-office tooth whitening was deemed the most suitable. The soft tissue—gingivae, tongue and lips—must be protected (Fig. 2). The product is applied to the vestibular aspects of the teeth (Fig. 3) and renewed every 15–20 minutes. A good result can be obtained (Fig. 4) with a gentle and efficient product containing 6% hydrogen peroxide (Opalescence Office, Ultradent Prod- ucts; Fig. 5). Hydrogen peroxide was chosen because, being the active ingredient, its efficacy is immediate. A 6% concentration is the limit, but it is strong enough to observe a difference and low enough to avoid temporary thermic hypersensitivity. A take-home whitening process entails the use of trays loaded with tooth whitening gel. After an orthodon- tic treatment, two options are available. An impression of both arches is taken, then stone models are prepared. A soft tray sheet is thermoformed, which allows the making of custom whitening trays (Fig. 6). At the second appoint- ment, the patient receives the trays and the product, together with the user instructions for one or two weeks 18 ortho 2 2018