Crowns of pure porcelain are generally considered the most attractive, but crowns layered with gold and porcelain are aesthetically comparable and much stronger. On the other hand, improper crowning can worsen the condition of the patient's teeth and gum. These products include toothpastes, mouthwashes and special chewing gums. No such OTC product contains enough hydrogen peroxide to affect the color of dental enamel. Furthermore, the hydrogen peroxide they may contain does not stay on teeth long enough to have any appreciable dental effect.
Some toothpastes contain papain, an enzyme used to tenderize meat, as a whitener.
Papain can dissolve some stains, but salivary dilution and the brevity of normal brushing would prevent its doing so. The best way to deal with halitosis is to have one's teeth cleaned properly and regularly by a dentist or dental hygienist, to undergo periodontal therapy if it is necessary, to brush one's teeth and tongue carefully twice a day, to floss one's teeth daily and meticulously, and to refrain from smoking. The psychological methods used to market cosmetic dental treatments are the movement's most noxious feature. Dentists are encouraged to evaluate every patient's smile. Sensitivity about one's physical appearance is common.