Eight-year outcome of posterior inlay-retained all-ceramic fixed dental prostheses.
OBJECTIVE
The main goal of this prospective clinical study was to evaluate the outcome of inlay-retained fixed dental prostheses (FDPs) made from heat-pressed lithium-disilicate glass-ceramic.


METHODS
Forty-five FDPs were placed in 42 patients (21 women, mean age 36.1 years and 21 men, mean age 42.0 years). The FDPs replaced 4 premolars and 19 molars in the maxilla and 4 premolars and 18 molars in the mandible. Preparations were performed in accordance with general principles for ceramic inlay restorations. Five of the 45 FDPs were hybrid-retained restorations, i.e. one abutment tooth with an inlay retainer and one with a full crown retainer. All FDPs were pressed in one piece using lithium-disilicate ceramic (IPS e.max Press, Ivoclar Vivadent). The minimum dimensions for the proximal connector were 4mm in height and 4mm in width (16 mm(2)) with a minimum occlusal ceramic thickness of 1.5mm. The surfaces of the inlay retainer were conditioned by etching with hydrofluoric acid 5% and silane application. Standard adhesive luting techniques were performed using a dentin adhesive (Syntac Classic, Ivoclar Vivadent) and a resin composite (Variolink II, Ivoclar Vivadent). Clinical follow-up examinations were performed annually.


RESULTS
The mean observation periods were 70 months (minimum 4, maximum 123 months). Twenty-seven FDPs (60%) failed during the observation period and had to be replaced. The Kaplan-Meier survival rate for inlay-retained FDPs was 57% after 5 years and 38% after 8 years, while for hybrid-retained FDPs it was 100% after 5 and 60% after 8 years.


CONCLUSIONS
Inlay-retained FDPs made from lithium-disilicate ceramic present a high clinical failure rate and therefore cannot be recommended.
Harder
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S
Department of Prosthodontics, Propaedeutics and Dental Materials, Christian-Albrechts University, Arnold-Heller Str. 16, 24105 Kiel, Germany.
Wolfart
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S
Eschbach
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S
Kern
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M
D000134:Acid Etching, Dental / Q000379:methods; D000328:Adult; D000368:Aged; D002516:Ceramics / Q000737:chemistry; D003442:Crowns; D000044:Dental Abutments; D003776:Dental Porcelain / Q000737:chemistry*; D019232:Dental Restoration Failure; D017220:Dentin-Bonding Agents / Q000737:chemistry; D003779:Denture Design; D003781:Denture Retention; D003830:Denture, Partial, Fixed; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006858:Hydrofluoric Acid / Q000737:chemistry; D007284:Inlays; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D019279:Resin Cements / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D013499:Surface Properties; D016896:Treatment Outcome; D055815:Young Adult
D017220:Dentin-Bonding Agents; C508050:IPS e.max Press; D019279:Resin Cements; D012821:Silanes; C078484:Syntac dentine adhesive; C493120:lithia disilicate; D003776:Dental Porcelain; C103502:Variolink; C023506:Glass ceramics; D006858:Hydrofluoric Acid