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Gerard Chiche

Publications and source records attributed to Gerard Chiche.

3 recordsLinked to original sources
PubMed2004

In vitro fracture strength of teeth restored with different all-ceramic crown systems.

STATEMENT OF PROBLEM: There is insufficient knowledge of the strength of all-ceramic crowns bonded to natural teeth to warrant the use of all-ceramic crowns in place of metal-ceramic crowns. PURPOSE: The purpose of this study was to evaluate and compare fracture resistance of crowns made of 3 different types of 2 all-ceramic crown systems-0.4-mm and 0.6-mm aluminum oxide coping crowns and zirconia ceramic coping crowns-and metal-ceramic crowns. MATERIAL AND METHODS: Forty intact, noncarious human maxillary central incisors were divided into 4 groups (n=10): Group MCC (control), metal-ceramic crown (JRVT High Noble Alloy); Group AC4, crown with 0.4-mm aluminum oxide coping (Procera AllCeram); Group AC6, crown with 0.6-mm aluminum oxide coping (Procera AllCeram); and Group ZC6, crown with 0.6-mm zirconia ceramic coping (Procera AllZirkon). Teeth were prepared for complete-coverage all-ceramic crowns so that a final dimension of 5.5 +/- 0.5 mm was achieved incisocervically, mesiodistally, and faciolingually. A 1.0-mm deep shoulder finish line was used with a rounded internal line angle. All restorations were treated with bonding agent (Clearfil SE Bond) and luted with phosphate-monomer-modified adhesive cement (Panavia 21). Fracture strength was tested with a universal testing machine at a crosshead speed of 2 mm per minute with an angle of 30 degrees to the long axis of the tooth after restorations were stored in 100% relative humidity of a normal saline solution for 7 days. The mode of fracture was examined visually. Means were calculated and analyzed with 1-way ANOVA and Tukey's HSD (alpha=.05). RESULTS: The means of fracture strength were: Group MCC, 405 +/- 130 N; Group AC4, 447 +/- 123 N; Group AC6, 476 +/- 174 N; and Group ZC6, 381 +/- 166 N. There was no significant difference between groups ( P =.501). The mode of failure for all specimens was fracture of the natural tooth. CONCLUSIONS: There was no significant difference in the fracture strength of the teeth restored with all-ceramic crowns with 0.4- and 0.6-mm aluminum oxide copings, 0.6-mm zirconia ceramic copings, and metal ceramic crowns.

Aluminum Oxide↗
PubMed2003

Long-term resin bond to densely sintered aluminum oxide ceramic.

BACKGROUND: Densely sintered aluminium oxide ceramic is a popular material for ceramic copings and all-ceramic restorations. A strong, predictable, and long-term durable resin bond is key for long-term clinical success of bonded alumina-based restorations. PURPOSE: The purpose of this study was to measure and compare in vitro shear bond strengths of three resin cements with and without their corresponding silane coupling/bonding agent to air particle- abraded densely sintered aluminum oxide ceramic after long-term water storage and thermocycling. MATERIALS AND METHODS: Composite resin cylinders were bonded to air particle-abraded samples of densely sintered aluminum oxide ceramic with Noribond DC (Noritake Dental Supply, Inc., Aichi, Japan), Panavia 21 EX (Kuraray, Osaka, Japan), and Variolink II (Ivoclar Vivadent, Schaan, Liechtenstein), which were used with and without their corresponding silane coupling and bonding agents (n = 15). All specimens (N = 90) were stored for 180 days in water and subjected to repeated thermocycling for a total of 12,000 cycles before shear bond strength was tested. Data were analyzed with the Kruskal-Wallis test and the Wilcoxon two-sample rank sum test at the 5% level of significance. RESULTS: Most groups had no or only minimal bond strength to densely sintered alumina after simulated aging. Panavia had the highest bond strength without silane/bonding agent application. Noribond with its silane/bonding agent revealed the highest overall bond strength, which was significantly greater than that of either Variolink or Panavia after silanization. CONCLUSIONS: Resin cements revealed significantly different bond strengths, and the use of silane coupling and bonding agents had various effects on the resin bond to pure densely sintered alumina. CLINICAL SIGNIFICANCE: Selection of the proper cement/bonding system is fundamental to clinical long-term success of bonded alumina-based restorations. Noribond with its bonding agent and ceramic primer seem to fulfill these requirements under clinically relevant testing conditions.

Air Abrasion, Dental↗