Influence of implant abutment angulations and two types of fibers on the fracture resistance of ceramage single crowns.
OBJECTIVE
To assess the effect of three implant abutment angulations and two types of fibers on the fracture resistance of overlaying Ceramage single crowns.


METHODS
Three groups, coded A to C, with different implant abutment angulations (group A/0°, group B/15°, and group C/30° angulation) were restored with 45 overlay composite restorations; 15 Ceramage crowns for each angulation. Groups A, B, and C were further subdivided into three subgroups (n = 5) coded: 1, crowns without fiber reinforcement; 2, crowns with Connect polyethylene reinforcement; and 3, crowns with Interlig glass reinforcement. All crowns were constructed by one technician using the Ceramage System. The definitive restorations (before cementation) were stored in distilled water at mouth temperature (37°C) for 24 hours prior to testing. Before testing, the crowns were cemented using Temp Bond. The compressive load required to break each crown and the mode of failure were recorded. The speed of testing was 1 mm/min. The results were statistically analyzed by two-way ANOVA (p < 0.05). The tested crowns were examined using a stereomicroscope at 40×, and selected crowns (five randomly selected from each group) were further examined by scanning electron microscopy (SEM) to reveal the composite-fiber interface.


RESULTS
Fracture resistance of single crowns was not affected (p > 0.05) by the different abutment angulations chosen (0°, 15°, 30°) or fiber reinforcement (Connect and Interlig fibers). Crowns in group A exhibited average loads to fracture (N) of A1 = 843.57 ± 168.20, A2 = 1389.20 ± 193.40, and A3 = 968.00 ± 387.53, which were not significantly different (p > 0.05) from those of groups B (B1 = 993.20 ± 327.19, B2 = 1471.00 ± 311.68, B3 = 1408.40 ± 295.07), or group C (C1 = 1326.80 ± 785.30, C2 = 1322.20 ± 285.33, C3 = 1348.40 ± 527.21). SEM images of the fractured crowns showed that the origin of the fracture appeared to be located at the occlusal surfaces of the crowns, and the crack propagation tended to extend from the occlusal surface towards the gingival margin.


CONCLUSIONS
Implant abutment angulations of 0°, 15°, and 30° did not significantly (p > 0.05) influence the fracture resistance of overlaying Ceramage single crowns constructed with or without reinforcing fibers. The two types of fibers used for reinforcement (Connect and Interlig) had no effect (p > 0.05) on the fracture resistance of overlaying Ceramage single crowns.
Faculty of Dentistry, the University of Sydney, Sydney, Australia. ayman.ellakwa@sydney.edu.au
Ayman
A
Ellakwa
F Elizabeth
FE
Martin
Iven
I
Klineberg
D002484:Cementation / Q000379:methods; D003188:Composite Resins / Q000737:chemistry; D019245:Compressive Strength; D003442:Crowns; D059605:Dental Implant-Abutment Design; D003764:Dental Materials / Q000737:chemistry*; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000295:instrumentation; D005054:Eugenol / Q000737:chemistry; D005898:Glass / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D020959:Polyethylene / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry; D015034:Zinc Oxide / Q000737:chemistry; D015035:Zinc Oxide-Eugenol Cement / Q000737:chemistry
D003188:Composite Resins; D003764:Dental Materials; D015035:Zinc Oxide-Eugenol Cement; C009753:fiberglass; D014867:Water; D005054:Eugenol; C076899:Temp-Bond; D020959:Polyethylene; D015034:Zinc Oxide