ABSTRACT: 0076

Wettability of Polymerized Surfaces of Resin Composites at Oral Temperature

S.S. KHAJOTIA, J.K. FLEMING, and M.G. DUNCANSON, Jr., University of Oklahoma Health Sciences Center, Oklahoma City, USA

Objectives: To measure the time-dependent wettability of water on selected polymerized surfaces of restorative resins at oral temperature. Methods: Specimens (d=6.0mm, h=3.6mm) of restorative resins 4-Seasons (FS; Ivoclar-Vivadent), Charisma (CH; Heraeus-Kulzer), Estelite∑ (ES; Tokuyama), Esthet-X (EX; Dentsply-Caulk), Gradia-Direct (GR; GC-Corp.), and TPH³ (TP; Dentsply-Caulk) were fabricated in a stainless-steel mold. The flat surfaces of the cylindrical specimens were polymerized against either a glass slab (control), Mylar™ strips or Toffelmire™ stainless-steel matrices (n=90). These unpolished surfaces were tested within 90min after polymerization by dispensing a 3μL drop of deionized, filtered water onto the specimen’s surface in a contact angle goniometer (OCA15-Plus, Future Digital Scientific Corp.). High-resolution digital images of the axisymmetric sessile drop were recorded @1frame/second for 8min at 37°C. Profiles of the drops were analyzed using the goniometer’s software to determine contact angle (θ) values using the Laplace-Young equation. Data were compared by General-Linear-Models and Student-Newman-Keuls (SNK) tests (α=0.05). Results: For a majority of the surface groups tested, a rapid decrease in θ values was observed for the first 2-3 minutes until a minimum value (θ_min) was reached, followed by a slight increase until 8min. Mean θ values ranged from 56.4º-76.9º at drop placement to 44.2º-53.7º at 8min. For the three surfaces studied, statistically significant differences in θ_min values were observed for each resin. Mean ± StdDev θ_min (degrees) values were:

Resin/Surface

CH

ES

EX

FS

GR

TP

Mylar

48.96±1.53^A

44.58±1.44^A

49.66±1.45^A

50.06±0.90^A

50.18±1.41^A

50.98±0.94^A

Glass(control)

46.36±0.38^B

43.56±1.24^A

49.48±0.55^A

47.40±1.53^B

49.50±0.83^A

50.94±0.66^A

Steel

40.76±0.71^C

37.44±1.92^B

43.94±2.06^B

47.12±0.90^B

45.28±1.33^B

42.02±0.94^B

* Superscript letters denote SNK rankings (p<0.003)

Conclusions: Contact angles decreased with time at 37ºC for all resins. Mean θ_min values differed with surface against which they were polymerized, with stainless-steel yielding the lowest mean value. Funding: NIH/NCRR grant P20RR018741 and Oklahoma Dental Foundation.

Seq #21 - Physical Properties of Resin Composite Materials
8:00 AM-9:30 AM, Thursday, April 3, 2008
Hilton Anatole Hotel Grand Ballroom B

Back to the Dental Materials 6: Polymer-based Materials - Physical Properties and Performance Program