A 5-Year Prospective Clinical Study on Core Restorations Without Covering Crowns

Traditionally, structurally compromised and endodontically treated teeth are restored with post-and-core restorations and covered with conventional crowns. The purpose of this study was to explore whether direct composite buildup restorations, with or without a post and not protected by a covering cast crown, can show acceptable durability over a 5-year observation period. Materials and Methods: The present study was one part of a series of multipractice clinical trials in which the clinical behavior of various types of buildup restorations was the central theme. All patients and teeth included in the present trial were selected as previously described and were chosen because they were either unwilling to have or could not afford a cast crown to cover the buildup restoration. They were treated with a direct composite crown. This trial compared 99 of these restorations either with (n = 53) or without (n = 46) a prefabricated post (Radix or RS; Maillefer) in 87 patients (43 men, 44 women). Application of a post was assigned by balanced drawing. Cores were made from Clearfil Core resin composite (Kuraray), and the restoration was finally covered and finished with Clearfil Ray Posterior (Kuraray). The restorations were made in 27 molars, 54 premolars, and 18 anterior teeth (Fig 1). Operators (17 general practitioners and 1 university clinician) were instructed to strictly observe protocols, and the operative procedures were calibrated. Before entering the study, patients were informed about the protocol, and those who agreed signed an informed consent form. The patients were reviewed at regular 6-month recalls. Life tables were constructed, and log-rank and Wilcoxon tests were used to test the variable "post" for its influence on restoration longevity, with a cutoff value of P = .05. Results: None of the post-free restorations failed (100% survival). Two restorations with posts failed after almost 5 years (survival 96% ± 2%). Both failures were in the maxillary left second premolar and comprised dislodgment of the restorations, with tooth fracture above the cementoenamel junction. Survival difference was not statistically significant. Discussion: The restoration of structurally compromised and endodontically treated teeth with complete composite buildup restorations has been previously described (Fokkinga et al; Roeters; and Smidt and Venezia). However, the reports are in vitro and from short-term study periods. While direct comparison is inappropriate (no intertrial randomization between the present study and the parallel trial), it is worth mentioning that the restorations in the present study showed a similar survival rate to the crowned buildup restorations in the parallel trial. It therefore appears that the technique of direct teeth restorations with resin composite is both promising and feasible, particularly when transitional solutions are required for teeth that need longer evaluation periods. The need for posts in buildup restorations for cast crowns has been questioned in the dental literature. The present study does not support the need for posts for structurally compromised and endodontically treated teeth restored with composite buildups and not covered by cast crowns.