Overview: Rehabilitation of Natural Teeth
An indirect restoration requires taking an impression and employing a dental laboratory to fabricate the prosthesis. Conversely, a direct restoration is carried out chair-side, usually in a single visit, without using a dental laboratory. Dental prostheses can either be intra– or extracoronal.
Indirect Intracoronal Prostheses
Intracoronal prostheses are defined as those surrounded by one or more natural tooth surface(s). This categorisation is broadly based on Black’s cavity classification:
- Class I: lesions of pits and fissures of all teeth, predominantly in premolars and molars;
- Class II: lesions on the proximal surfaces of posterior teeth, referred to as MO (mesial-occlusal), DO (disto-occlusal), and MOD (mesial-occlusal-distal);
- Class III: lesion in the anterior teeth, similar to a class II lesion, the class III lesion typically appears at the contact point;
- Class IV: the class IV lesion is a class III lesion including the incisal corner of an anterior tooth;
- Class V: typically occurs at the cervical margins on the buccal, rather than the lingual, aspect of any tooth;
- Class VI: not originally in Black’s classification, but has become accepted as an additional lesion that occurs on the tips and cusps of posterior teeth, or along the biting surfaces of the incisors.
Three developments have made Black’s cavity classification redundant. First, research has elucidated biological mechanisms such as demineralisation/remineralisation and the role of fluoride ion, and removal of infected and affected dentine is no longer a prerequisite. Second, new restorative materials such as resin (plastic)-based adhesives and filling materials, and therapeutic filling materials, which are both bacteriostatic and bactericidal, avoid removing vast amount/>