Ceramic (Feldspathic & IPS Empress II) vs. laboratory composite (Gradia) veneers; a comparison between their shear bond strength to enamel; an in vitro study

Abstract

Patient demand for aesthetic dentistry is steadily growing. Laminates and free metal restorations have evolved in an attempt to overcome the invasiveness nature of full veneer restorations. Although many different materials have been used for making these restorations, there is no single material that fits best for all purposes. Two groups of ceramic material (Feldspathic and IPS Empress II) and one group of laboratory composite (Gradia) discs (10 discs in each group; 4 mm in diameter and 2 mm in thickness) were prepared according to the manufacturer's instruction. The surface of ceramic discs were etched and silanized. In Gradia group, liquid primer was applied on composite surfaces. Thirty freshly extracted sound human molars and premolars were randomly divided into three groups. The enamel surface of each tooth was slightly flattened (0.3 mm) on the buccal or lingual side and then primed and cemented to the prepared discs with the aid of a dental surveyor. The finishing specimens were thermocycled between 5 degrees C and 55 degrees C for 2500 cycles and then prepared for shear bond strength testing. The resulting data were analyzed by one-way anova and Tukey HSD test. The fractured surfaces of each specimen were inspected by means of stereomicroscope and SEM. There is significant difference between the bond strength of materials tested. The mean bond strengths obtained with Feldspathic ceramic, IPS Empress II and Gradia were 33.10 +/- 4.31 MPa, 26.04 +/- 7.61 MPa and 14.42 +/- 5.82 MPa, respectively. The fracture pattern was mainly mixed for ceramic groups. More scientific evidence needed for standardization of bonding protocols.

Internal adaptation, marginal accuracy and microleakage of a pressable versus a machinable ceramic laminate veneers

“…The adhesive resin cement is subjected to dynamic loading, thermal cycling, and is influenced by the hydrolytic effect of water and different chemicals present in the mouth. 3,4 External marginal adaptation of ceramic veneers, which is defined as the vertical distance between the finish line of the prepared tooth and the margins of the fabricated veneers 5 plays an important role for their success. Close proximity between the margin of the restorations and the tooth structure protects the adhesive resin cement from excessive exposure to the oral cavity leading eventually to slow process of gradual disintegration of its chemical, physical, and mechanical properties resulting in microleakage, recurrent decay, discolouration of the tooth structure, and fracture of the cemented veneers.…”

The Effect of Multiple Firings on Microtensile Bond Strength of Core‐Veneer Zirconia‐Based All‐Ceramic Restorations

“…Along with the growth of public knowledge regarding newly developed materials and advanced manufacturers’ products, the restorative dentist faces a challenge considering the use of the latest inventions in esthetic dental materials. Although ceramics are mostly regarded as the best materials in esthetic dentistry, these materials all suffer from inherent brittleness 1 …”

“…Recently, zirconium‐based ceramics have been introduced. They use the principles of computer‐aided design/computer‐aided manufacturing (CAD/CAM) for fabrication of the crowns and fixed partial dentures (FPDs) 1 …”

Predictability of CAD/CAM fabricated aluminum oxide core crowns and veneers

“…Traditional techniques utilized to secure porcelain veneers to the underlying tooth structure utilizing bonding technology whereby micromechanical etching of the enamel is performed and then composite bonding is utilized to secure the etched and silanated veneer to the enamel (23,24). Assessment of the surface of the alumina core at high magnification (X500) (figure 4) fails to demonstrate roughness that is similar to that seen with etched feldspathic porcelain.…”

“…It is thought that careful attention to detail will lead to clinical success. Furthermore, the application of new materials and techniques creates a tremendous need for appropriate clinical guidelines (22)(23)(24). The purpose of this study was to evaluate the clinical performance of CAD/CAM generated aluminum oxide core crowns and veneers over a time frame of up to four years.…”