Dental Tribune Asia Pacific Edition No.7+8, 2017

Dental Tribune Asia Paciﬁ c Edition | 7+8/2017 SCIENCE & PRACTICE 11 Ach v g the best bond strength with VITA ENAMIC An interview with Dr Julián Conejo from the University of Pennsylvania, US Under the leadership of Prof. Markus B. Blatz, Chairman of the Department of Preventive and Restorative Sciences at Penn Dental Medicine (left), Dr Julián Conejo is currently investigating the properties of VITA Zahnfabrik’s hybrid ceramic VITA ENAMIC. A restoration must be conditioned for a reliable adhesive bond be- tween the luting composite and the hybrid ceramic. In a current in vitro study Dr Julián Conejo from the University of Pennsylvania is in- vestigating how different types of conditioning and protocols inﬂ u- ence the bond strength to the VITA ENAMIC hybrid ceramic (VITA Zahn- fabrik). In this interview, he talks about his ﬁ ndings and what to con- sider when aiming for optimal re- sults. Dr Conejo, could you brieﬂ y explain the study methodology? What pa- rameters were modiﬁ ed in the con- ditioning and pretreatment of the hybrid ceramic? Seventy test specimens of VITA ENAMIC were etched for 20, 60 or 120 seconds with 5 % hydro- ﬂ uoric acid. The etched surfaces were cleaned either with phos- phoric acid or in an ultrasound bath. For the study, including the control group with no pretreat- ment, seven different subgroups were formed. After the application of the bonding agent and the com- posite, the test specimens were stored in distilled water. The ﬁ nal shear strength was determined and the data was statistically ana- lysed. Based on your ﬁ ndings, how impor- tant is etching with 5 % hydroﬂ uo- ric acid for a reliable adhesive bond of the luting composite to the ce- ramic restoration? It is very important to apply hydrofluoric acid to create a roughened surface for good micromechanical retention. All etched sample specimens showed a signiﬁ cant increase in bond strength to the luting compos- ite. In order to ensure sustained clinical success of the restora- tion, hydrofluoric acid is a crit- ical process step for the treat- ment provider. Did the exposure time to the hydro- ﬂ uoric acid affect the bond strength of the luting composite? Different etching patterns on the test specimens were gener- 3 4 Fig. 1: Control group: unetched hybrid ceramic surface.—Fig. 2: Hybrid ceramic surface after hydroﬂ uoric acid etching for 20 seconds.—Fig. 3: Hybrid ceramic sur- face after hydroﬂ uoric acid etching for 60 seconds.—Fig. 4: Hybrid ceramic sur- face after hydroﬂ uoric acid etching for 120 seconds. Source of scanning electron microscopy images of VITA ENAMIC material samples: Julián Conejo 2016. 1 2

Dental Tribune Asia Pacific Edition No.7+8, 2017

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