Survival of Dicor glass-ceramic dental restorations over 14 years. Part II: effect of thickness of Dicor material and design of tooth preparation.
BACKGROUND
The influence of different restorative design features on the long-term survival of Dicor glass-ceramic restorations is not well understood.


OBJECTIVE
This study examined the relationship of different types of restorations and methods of preparation with the survival of Dicor glass-ceramic restorations functioning in vivo.


METHODS
A total of 1444 Dicor glass-ceramic restorations were placed on the teeth of 417 adults. Failure was defined as a restoration that required remake because of material fracture. Survival of restorations of different types and with different methods of preparation was described by using Kaplan Meier survivor functions. Statistical significance between restoration type and preparation method was determined with the log rank test.


RESULTS
Probability of survival of a typical partial coverage restoration was 92% at 11.3 years. There was no statistically significant difference between the survival of inlay or onlay restorations. For the 91 cores used for pulpless teeth, none failed over a total cumulative monitoring period of 419 years. There was no significant difference in survival of acid-etched Dicor restorations that were placed on shoulder or chamfer preparations. Thickness measured at the midpoint of the labial, lingual, mesial, distal, and midocclusal surfaces did not relate to risk of failure.


CONCLUSIONS
The majority of Dicor glass-ceramic partial coverage inlay and onlay restorations and cores survived over time. Survival of restorations with either chamfer or shoulder preparations did not differ whether the restoration was acid-etched. Thickness of the restoration measured at the midaxial point of each surface did not relate to survival.
Malament
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Tufts University School of Dental Medicine; and Forsyth Dental Center, Boston, Mass., USA. Kamalam@IBM.Net
Socransky
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D000134:Acid Etching, Dental; D000328:Adult; D002516:Ceramics / Q000737:chemistry; D003776:Dental Porcelain / Q000737:chemistry; D019232:Dental Restoration Failure; D003793:Dental Restoration, Permanent; D005500:Follow-Up Studies; D005898:Glass / Q000737:chemistry; D006801:Humans; D007284:Inlays; D011176:Post and Core Technique; D011336:Probability; D012307:Risk Factors; D013499:Surface Properties; D016019:Survival Analysis; D019231:Tooth Preparation, Prosthodontic / Q000379:methods*; D019553:Tooth, Nonvital / Q000534:rehabilitation
C047475:Dicor ceramic; D003776:Dental Porcelain