Providing excellent dental care begins with a comprehensive exam by the dentist. The exam covers 4 basic areas. These areas include the teeth, the support, the function, and the esthetics of the teeth. The exam of the teeth identifies areas of decay, defective restorations, questionable restorations, teeth at risk of breakage, and nerve health. The exam of the support of the teeth, evaluates gum health, bone support for the teeth, and an oral cancer screening. The examination of the function of the teeth includes evaluation of "out of normal" function, known as "parafunctional habits". This area of the exam looks at the bite, the TMJ, erosion and wear patterns. It also identifies destructive habits, such as clenching, grinding (bruxism), nail biting, toothpaste abusive, and erosion from certain foods and drinks. Last but not least, the esthetics of the teeth is evaluated. This part of the exam includes evaluation of the color, the shape and the position of the teeth. Tooth aesthetics also depend on the shape of the gum surrounding the teeth. Therefore, gum shape, thickens and color are evaluated as part of the aesthetic part of the exam .