Methods: Light-cure filled (F) and unfilled (U) bonding resins were prepared from a basis resin of 45% bis-EMA, 40% TEGDMA, and 15% HEMA. Fluorinated TEGDMA (f), 0-30 wt% was substituted for some TEGDMA as shown in the table. Class V restorations were made in 50 extracted human molar teeth, 3 mm length X 2 mm width X 1.5 mm depth centered on the cementoenamel junction using these 8 experimental formulations and 2 commercial bonding resins (n = 5), OptiBond Solo Plus (OB, Kerr) and All-Bond 2 (AB, Bisco) following a standard clinical protocol. The teeth were thermocycled 1500 times between 5 °C and 55 °C wirh 1-minute dwell times. Teeth were removed, dried, varnished, and placed in 50 w/v% silver nitrate solution at 37 °C for 24 hours in total darkness. The teeth were rinsed and sectioned through the restorations with a wafering saw yielding haves. For each half, dye penetration was assessed at X80 and measured in mm from margin to axial wall for occlusal (O) and cervical (C) margins.
Results: Mean depths of dye penetration shown in the table.
|
R1F0f |
R1U0f |
R2F17f |
R2U17f |
R3F30f |
R3U30f |
R4F24f |
R4U24f |
OB |
AB |
O |
.35±.5 |
.28±.5 |
.52±.7 |
.76±.7 |
.94±.4 |
1.1±.4 |
.61±.5 |
.64±.6 |
.06±.2 |
.6±.3 |
C |
.69±.5 |
.73±.5 |
.84±.7 |
.92±.6 |
1.1±.2 |
1.1±.4 |
.82±.3 |
.72±.5 |
.33±.5 |
.29±.4 |
The data was analyzed statistically (p<0.05) using ANOVA. At the occlusal margins, all R1, OB, and AB leaked significantly less than the fluorinated composite resins. At the cervical margins, OB and AB leaked significantly less than all other groups.
Conclusions: Fluorinated TEGDMA did not reduce microleakage of composite resins.