Shear bond strength of denture teeth to heat- and light-polymerized denture base resin.
OBJECTIVE
To evaluate the shear bond strengths of highly cross-linked denture teeth bonded to heat-polymerized poly(methyl methacrylate) (PMMA) or a light-polymerized urethane dimethacrylate (UDMA) denture base resin with or without a diatoric and with or without an acrylate bonding agent.


METHODS
The denture base resins tested were Lucitone 199 (heat-polymerized PMMA) and Eclipse (light-polymerized UDMA). One hundred sixty mandibular central incisor denture teeth were divided into four groups (n = 40): group 1: ground surface as control; group 2: ground surface with diatoric; group 3: ground surface with bonding agent; group 4: ground surface with bonding agent and diatoric. Half of each group (n = 20) was processed with either heat- or light-polymerized resin. All specimens were treated with thermocycling for 1000 cycles, alternating between 5 and 55 °C with a dwell time of 30 seconds. Half the specimens in each group were treated with cyclic loading at 22 N for 14,400 cycles at 1.5 Hz. All specimens were tested with shear load to failure. Data were analyzed with student's t-test, 2- and 3-way ANOVA, and Dunnett's T3 method (p < 0.05).


RESULTS
Statistical analysis demonstrated no significant effect on shear bond strength from cyclic loading. For the Lucitone 199 (L) specimens, mean shear bond strengths and standard deviations were (N) 66.5 ± 28.4, 72.7 ± 31.5, 80.6 ± 17.1, and 76.9 ± 21.9 for groups 1L, 2L, 3L, and 4L, respectively. For the Eclipse (E) specimens, mean shear bond strengths and standard deviations were (N) 3.7 ± 1.2, 7.3 ± 3.3, 90.0 ± 20.7, and 94.2 ± 17.8 for groups 1E, 2E, 3E, and 4E, respectively. No statistically significant differences in shear bond strengths were noted for the Lucitone 199 groups (p = 0.11). Eclipse shear bond strengths were significantly higher in groups 3E and 4E than in groups 1E and 2E (p ≤ 0.05). In a 3-way ANOVA for groups 3 and 4, the shear bond strengths for the Eclipse specimens were significantly higher than the Lucitone 199 specimens (p = 0.01).


CONCLUSIONS
When evaluating the shear bond strength of IPN denture teeth to denture base resins, specimens using an acrylate bonding agent with the Eclipse (light-polymerized) resin yielded significantly higher shear bond strengths than all of the Lucitone 199 groups and the Eclipse resin groups without a bonding agent.
Graduate Prosthodontics, University of Washington, Seattle, WA, USA. mlfletcher@llu.edu
Madelyn L
ML
Fletcher-Stark
Kwok-Hung
KH
Chung
Jeffrey E
JE
Rubenstein
Ariel J
AJ
Raigrodski
Lloyd A
LA
Mancl
D000180:Acrylic Resins / Q000737:chemistry; D000268:Adhesiveness; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry* / Q000528:radiation effects; D003799:Dental Stress Analysis / Q000295:instrumentation; D003819:Denture Bases; D006358:Hot Temperature; D006801:Humans; D008027:Light; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry* / Q000528:radiation effects; D008855:Microscopy, Electron, Scanning; D058105:Polymerization; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D011140:Polyurethanes / Q000737:chemistry* / Q000528:radiation effects; D033081:Shear Strength; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014093:Tooth, Artificial
D000180:Acrylic Resins; D003188:Composite Resins; D003764:Dental Materials; C509237:Eclipse Prosthodontic Resin; D008689:Methacrylates; D011140:Polyurethanes; C029824:urethane dimethacrylate luting resin; C040291:Lucitone; D019904:Polymethyl Methacrylate