|0425 Condensation Forces and Properties of Amalgam Specimens Prepared by Clinicians|
D. SARANTOPOULOS, D.W. BERZINS, and V. DHURU, Marquette University, Milwaukee, WI, USA|
Objectives: The purpose of this investigation was to evaluate the amalgam condensation forces (CF) generated by clinicians under laboratory conditions and determine the compressive strength (CS), corrosion potential (CP), and corrosion current (CC) of the resulting specimens. Results are also compared to those from fourth-year dental students (Abst#1933, 2006 AADR).
Methods: Ten experienced clinicians (n=5 males; n=5 females) were recruited. A cylindrical split mold (6mm height x 3.2mm diameter) and a fixture to rest the operator's hand while condensing amalgam were set on a universal testing machine. An admixed amalgam (Dispersaloy) was condensed by the subjects utilizing a 1mm diameter condenser. The hand-rest eliminated all but the vertical condensing forces. The forces were plotted against time and integrated to yield total condensing force in N×s for each specimen. Three specimens from each subject were tested for CS and one was analyzed with potentiodynamic polarization to determine CP and CC. A t-test and ANOVA were employed to determine differences in force/properties between the two groups of clinicians and for comparison to the students, respectively.
Results: No significant differences (p>0.05) were found among CF, CP, and CC, which also varied considerably. The mean (standard deviation) CFs generated by male and female clinicians were 274 (216) and 213 (140) N×s, respectively. The CP ranged from -0.242 to -0.317 V and CC ranged from 42 to 746 nA. The CS of amalgam condensed by female clinicians, 306 (44), was significantly greater (p<0.05) than that from males, 244 (18). Similar to other parameters, a wide range of values (183 to 382 MPa) were found. No differences in forces/properties were found when comparing dental students to clinicians.
Conclusion: As in dental students, a wide range of condensation forces and amalgam properties are evident in specimens prepared by clinicians.
|Seq #75 - Amalgam and biological tissues|
2:00 PM-3:15 PM, Thursday, March 22, 2007 Ernest N. Morial Convention Center Exhibit Hall I2-J