for root treated teeth is justified when the surface area of the access cavity exceeds one third of the occlusal surface of the tooth, when the lingual or buccal walls are undermined or when the mesial and distal marginal ridges are missing. Clinical stages of dental crown provision Assessment Choice of restoration Tooth preparation Construction and fit of temporary restoration Tooth preparation impressions Fit of definitive restoration Review Assessment In order to ensure optimum condition and longevity for the proposed crowns, several factors need to be explored by conducting a thorough and targeted patient history and clinical dental examination. These factors include: Patient factors Patient expectations Patient motivation to adhere to the treatment plan and maintain results Financial and time costs to the patient Biological factors Periodontal health status and periodontal disease risk Pulpal health and endodontic disease risk Caries and caries risk Occlusion and occlusal problems risk Mechanical factors Amount of remaining tooth structure Height and width of tooth to be prepared Attachment levels of the tooth to be prepared Root shape and length of the tooth to be prepared Aesthetic factors Choice of restoration The choice(s) of crown restoration can be described by: The dimensions and percentage coverage of the natural crown Full crowns 3/4 and 7/8 crowns Material to be used Metal Metal-ceramic crowns Full ceramic crowns 3/4 and 7/8 crowns These restorations are a hybrid between an onlay and a full crown. They are named based on the estimated wall coverage of the walls of the tooth; e.g. the 3/4 crown aims to cover three out of the four walls, with the buccal wall being usually spared, thus reducing sound tooth tissue to be prepared. They are normally fabricated in gold. Grooves or boxes are normally added to the preparations as close to the unprepared wall as possible to increase retention of the crown. Despite its advantages of reducing sound tooth preparation, these crowns are not commonly prescribed in practice because they are technically difficult and have poor patient acceptability due to the metal showing through in their smile. Full metal crowns As the name suggests, these crowns are entirely cast in a metal alloy. There are a multitude of alloys available and the selection of a particular alloy over another depends on several factors including cost, handling, physical properties, biocompatibility. The American Dental Association categories alloys in three groups: high-noble, noble and base metal alloys.