IADR Abstract Archives
Creep compliance of the new and original formulations of Viscogel
Objectives: Viscoelastic properties of dental tissue conditioners are important as they determine their ability to maintain good adaptation of the oral tissues. The purpose of this study was to compare the creep compliance of the new Viscogel formulation to its old version.
Methods: The two materials tested were Viscogel old formulation (Vg old), Viscogel new formulation (Vg new) both from Dentsply. P/L ratios (g/ml) used: 1.3 and 1.8. Hardness was measured using Wallace shore A hardness testing machine according to ASTM D2240 using samples 100x20x10 mm. Materials were mixed, moulded to shape and then kept at 37oC prior to hardness being measured at 1 and 4 hours using dwell times of 1, 5, 10, 15, 20, 25 and 30secs. 6 measurements were taken for each specimen at each dwell time. Apparent Young's Modulus (E) was calculated using the equation: H = 100erf(kE1/2)
Where H = Shore A hardness, E = Young's modulus, k= 3.186x 10-4 Pa
Compliance was calculated as 1/E and then compliance ratio as compliance at time t/compliance at 1 sec.
Results: Compliance ratios for at 5 and 30 sec dwell times are shown in the table below
| VG old 1.3 1hr 4hr | VG old 1.8 1hr 4hr | VG new 1.3 1hr 4hr | VG new 1.8 1hr 4hr |
5 sec | 1.96 1.68 | 1.83 1.24 | 1.31 1.10 | 1.13 1.78 |
30 sec | 9.80 4.73 | 12.13 1.90 | 2.76 1.40 | 1.07 1.26 |
The compliance ratio for both materials at each P/L and each time point increased with dwell time. Generally the increase was more for VG old than VG new, for 1hr than 4hr and for 1.3 than 1.8.
Conclusions: The new Viscogel formulation exhibits less creep than the original formulation; this may influence its ability to adapt to changing contours of the oral tissues.