TITLE:
Diminished fracture initiation sites in ceramic layers bonded to glow-discharge treated substructure
AUTHORS:
Hyeongil Kim, Edward A. Monaco Jr., Frederick McIntyre, Elaine L. Davis, Robert E. Baier
KEYWORDS:
Porcelain Fracture; Glow Discharge Treatment; Metal Ceramic Crown; Porosity; Surface Energy
JOURNAL NAME:
Open Journal of Stomatology,
Vol.3 No.6,
August
28,
2013
ABSTRACT: A mechanically retentive structure and meticulous
surface cleanliness are critical factors in providing fracture resistance and
clinical success of metal ceramic restorations. This investigation compared
the porcelain/metal interfaces of deliberate compressive fractures of ceramic crowns
between conventional preparation and application of the Radio Frequency Glow
Discharge Treatment (RFGDT) before each bonding step. It evaluated RFGDT’s capacity
to improve wetting effectiveness and minimize porosity. Twelve metal ceramic crowns
were fabricated identically. RFGDT was applied to the metal substructures of
half the specimens before the ceramic layering process. All specimens were
fractured in the same manner by an applied compressive force to simulate dental
occlusive failure. Fracture surfaces were inspected by light and scanning
electron microscopy. Quantitative analyses of images were performed to identify
numbers, locations of cracks, porosity patterns, and other morphological
correlates of the fracture zones. There were significantly fewer voids per
millimeter at the interfaces in the RFGDT group than in the non-RFGDT group (t = 2.377, df = 9, p = 0.021). There
was a significant difference in the number of horizontal cracks per
millimeter between the groups (t = 2.132, df = 7, p = 0.035), with more cracks occurring in the non-RFGDT group. RFGDT
can improve the integrity of metal ceramic crowns by increasing the substratum
surface energy, improving porcelain wetting and spreading and thereby diminishing
the numbers of interfacial voids available for initiation of fracture. Routine
application of RFGDT should result in fewer cracks along metal/ceramic
interfaces in all restorative preparations.