A prospective 15-year evaluation of extensive dentin-enamel-bonded pressed ceramic coverages

The purpose of this study was to investigate the durability of extensive dentin-enamel-bonded posterior ceramic coverages in a 15 years follow-up.

All extensive dentin-enamel-bonded posterior partial and complete all-ceramic coverages placed during the period November 1992-December 1998 were included. In 121 patients, 252 coverages (IPS Empress) were placed. The adhesive bonding to dentin and enamel was performed with three 3-step and one 2-step etch and rinse bonding. In 106 restorations the classic Syntac was used in combination with the dual-cured resin composite Variolink. The other restorations were luted with the chemically cured resin composite Bisfil 2B and bonded with 3-step etch and rinse systems, classic Gluma (37), Allbond 2 (57), Syntac (32) or the 2-step etch and rinse system, One step (20). The ceramics were evaluated yearly by modified USPHS criteria during 15 years.

Postoperative sensitivity was registered in 4 patients during bite forces lasting for 2-4 weeks. Fifty-five of 228 coverages (24.1%) failed. The mean observation period of the acceptable coverages was 12.6 years (range 11-15 years). The main reasons for failure were lost restorations (18), ceramic fracture (16), and secondary caries (11). Significant differences in failure rate were observed between the dentin bonding agents but not between the two luting agents. Ceramic coverages placed on non-vital teeth failed in 39% and on vital teeth in 20.9% (p=0.014). Logistic regression indicated three significant predictors for failure of the coverages: gender and parafunctional habits of the patient and non-vitality of the tooth.

The technique investigated showed advantages like less destruction of healthy tissue, and avoiding of endodontic treatment and/or deep cervical placement of restoration margins to obtain retention.