the principles of treatment of dental defect restoration
1. saves tooth structure as possible (1) removing diseased tissue and prevent diseases from developing (2) create necessary space for restorations (3) restoration successfully in place (4) configuration and ensure that they get a good solid resistance (5) establish the correct appearance of occlusal relationships and harmony 2. Properly restore form and function (1) properly restoring the axis surface ① restored lips, buccal, lingual protrusion, bursting through the small or even no protrusion, gum will directly hit by food-induced trauma. Conversely, if crowns bursting over, massage of the gums because of lack of access to food and result in disuse atrophy. II restoration of adjacent surface of the protrusion and the adjacency relations, reconstruction of adjacent teeth and close contact to keep the teeth, dental arch form, preventing food impaction, dispersion forces. Different tooth contact area of different locations: anterior tooth contact area near the margin, posterior tooth contact area near the close to the edge, in the distal margin. (2) restoration of the outreach gap: the dome is the contact area between the two tooth surfaces, spaces around it for the outreach gap. Attention restoration should restore the right outreach gap to facilitate food row overflow, reduce the burden of periodontal, keeping the teeth clean to prevent gingivitis and caries bacteria. (3) restoration of occlusal surface morphology and occlusal relationships: properly restore occlusal surface morphology and occlusal relationship is an important part of restoring chewing functions in restored form, should pay attention to the masticatory function of molar and anterior teeth should pay attention to appearance and pronunciation.