ABSTRACT: 0379

Effects of Polymerization-Mode on the Push-Out Retention of Self-Adhesive Resin-Cements

A.H. CURY¹, T.A. PEGORARO², J.C. PEREIRA¹, B. SUH³, and R.M. CARVALHO³, ¹University of São Paulo, Bauru School of Dentistry, Brazil, ²University of Sao Paulo, Bauru School of Dentstry, Brazil, ³Bisco, Inc, Schaumburg, IL, USA

Objectives: To evaluate push-out retention strength of fiber posts cemented with two self-adhesive resin cements (RelyX Unicem, 3M ESPE and Biscem, BISCO Inc.) under different curing modes (dual-cured or self-cured), on each regional root-third. Methods: Twenty extracted human teeth were endodontically treated. Post space was prepared and cleaned (5% sodium hypochlorite), and roots were assigned to four groups (N=05): Group 1: Unicem light-cured; Group 2: Unicem self-cured; Group 3: Biscem light-cured; Group 4: Biscem self-cured. A Light-cure unit (VIP, BISCO, Inc.) was employed to irradiate the coronal aspect of each tooth for 20 sec@600mW/cm². For the self-cured mode, teeth were allowed to dark cure at 37^oC for 6 minutes. Each root was cut horizontally into 1mm-thick slices. A universal testing machine Vitrodyne V-1000 (Chatillon Force Measurement Systems) was utilized with a custom-made cylindrical plunger (0.79 mm diameter), which was positioned on the apical face of the root slice. The loading was applied (0.5mm/min) until complete post displace and extrusion from root slice. The results were calculated and expressed as the bond strength in MPa.

Results: MPa±SD (N). Data were analyzed by ANOVA and Tukey Test (p<0.05). Capital letters/Columns; Lowercase/rows.

Material	Polymerization Mode	Thirds^†			Total^†
Material	Polymerization Mode	Apical	Middle	Coronal	Total^†
Biscem	Light-cured	10,9±3,6(15)^a	8,9±2,8(15)^a	10,8±2,6(13)^a	10,1±3,1(43)^B
Biscem	Self-cured	7,9±3,4(19)^a	5,7±2,7(16)^ab	4,4±3,7(14)^b	6,3±3,6(49)^A
RelyX Unicem	Light-cured	6,4±2,3(13)^a	7,0±2,4 (12) ^a	9,1±4,9(12)^a	7,5±3,5(37)^A
RelyX Unicem	Self-cured	10,7±3,4(18)^a	7,0±1,8(16)^b	6,7±3,0(15)^b	8,3±3,4(49)^A

Results: ANOVA revealed that “polymerization mode” and interaction of “cement” and “polymerization mode” had significant influences on the push-out strength (p<0.05).

Conclusion: For some dual-cured resin-cements light-activation is further important to achieve optimal properties. When the self-cure mode was used highest values were recorded on the apical third.

Seq #70 - Cements
2:00 PM-3:15 PM, Thursday, July 3, 2008
Metro Toronto Convention Centre Exhibit Hall D-E

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