PARTIAL CERAMIC CROWNS. ESTHETIC AND TISSUE CONSERVATIVE RESTORATIONS – PART I: POSTERIOR TEETH

Background: Partial ceramic crowns (PCCs) are more tooth conservative and potentially less stressful for the periodontium than full coverage crowns and meet the esthetic demands of patients. Objective: evidence shall be provided, if PCCs are a reliable treatment option, and under which conditions. Data sources: this review is based on own published data and experiences and on a review of the literature. Results: Longevity of PCCs is in the range of partial crowns from gold alloys. Failures due to chip fractures, bulk fractures, or debonding can be avoided/reduced by proper technique. Most clinical experience exists with leucite reinforced silicate or lithium disilicate ceramics, either pressed or CAD/CAM processed. Tooth preparation must respect the need for sufficient ceramic thickness of at least 1.5 mm. Residual buccal or oral cusps of less than 2 mm thickness should be included in the preparation. Cavity preparation should be defect oriented with few parallel walls as guidance for placement. Dual curing luting composites together with etch and rinse (E&R) adhesives are standard. Self-adhesive materials can be used but are sensitive to tooth desiccation before luting. Clinical experience with new universal adhesives is limited, but available results are promising. Light curing should be performed by applying 32 J/cm2 from oral, buccal and occlusal aspects (silicate based ceramics). Conclusions: PCCs are a reliable treatment option for extended defects in posterior teeth. Special guidelines must be followed including sufficient ceramic thickness and proper adhesive technique to avoid failures