Smile is the centrepiece of overall beauty. The scientific and artistic principles that link all the facial features and structures together are often collectively referred to as the principles of 'smile design'. It includes fundamental aesthetic standards that help clinicians to design and create 'beauty' in a quantitative, scientific and predictable manner. The wrong smile in the wrong patient not only may look bizarre, but also may have adverse psychological and other effects on the patient. Conceiving, planning and providing the right, aesthetically pleasing smile for a patient is the challenge and professional fulfilment of high-quality aesthetic dentistry.