Load-bearing capacity of CAD/CAM milled polymeric three-unit fixed dental prostheses: effect of aging regimens.
OBJECTIVE
This study tested the fracture load of milled and conventionally fabricated polymeric and glass-ceramic three-unit fixed dental prostheses (FDPs) after aging.


METHODS
FDPs were fabricated (N = 1,050) from four computer-aided design and computer-aided manufacturing (CAD/CAM) resins: (1) AT (artBlock Temp); (2) TC (Telio CAD); (3) ZP (ZENO PMMA); (4) CT (CAD-Temp); two conventionally fabricated resins, (5) IES (integral esthetic press), (6) CMK (CronMix K), and a glass-ceramic (control) (7) PG (IMAGINE PressX). Specimens of each group were tested immediately after fabrication (n = 15 per material). Seventy-five FDPs per material type were stored in artificial saliva (37°C) and 15 of them were randomly selected after aging (1, 7, 28, 90, and 180 days) for fracture load measurement. The remaining specimens (n = 60 per material) were subjected to chewing simulation (×120.000-1.200.000, 49 N, 5°C/50°C). The data were analyzed using two-way and one-way ANOVA followed by Scheffé test.


RESULTS
The interactions between FDP materials and aging time in both storage media showed a significant impact on the results (p < 0.001). Among saliva storage groups, TC and ZP showed the highest, and PG the lowest fracture load (p < 0.05). AT and CT were not affected from chewing simulation. TC, ZP, and AT presented the highest in ascending order (p < 0.05), PG and CMK showed the lowest fracture load after chewing simulation (p < 0.001).


CONCLUSIONS
Aging did not influence the fracture load of FDPs made of CAD/CAM resins. FDPs made of glass-ceramic showed significantly lower fracture load than those of all resin FDPs.


CONCLUSIONS
Considering fracture load measurements, CAD/CAM resins tested could be alternative materials to glass-ceramic for FDP construction.
Clinic of Fixed and Removal Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, Zurich 8032, Switzerland. bogna.stawarczyk@zzm.uzh.ch
Bogna
B
Stawarczyk
Andreas
A
Ender
Albert
A
Trottmann
Mutlu
M
Özcan
Jens
J
Fischer
Christoph H F
CH
Hämmerle
D000180:Acrylic Resins / Q000737:chemistry; D001732:Bite Force; D002516:Ceramics / Q000737:chemistry*; D017076:Computer-Aided Design; D003799:Dental Stress Analysis / Q000295:instrumentation; D003779:Denture Design; D003823:Denture Rebasing; D003830:Denture, Partial, Fixed; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D020366:Methylmethacrylate / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D019904:Polymethyl Methacrylate / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry; D012464:Saliva, Artificial / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors
D000180:Acrylic Resins; D008689:Methacrylates; D011108:Polymers; D011140:Polyurethanes; D012464:Saliva, Artificial; C029824:urethane dimethacrylate luting resin; D020366:Methylmethacrylate; C006903:carbopol 940; C023506:Glass ceramics; D019904:Polymethyl Methacrylate