Objectives: The aim of this in-vitro study was to determine the fracture strength of adhesively luted composite veneered alloy fixed partial dentures (FPD). The influence of different polymerization conditions was investigated. Methods: 64 human molars were inserted in PMMA resin to simulate three-unit (10mm) oral situation. The roots of the teeth were covered with an about 1mm thick layer of polyether to simulate the periodontium. 32 frameworks were made of a high gold alloy (Targis Gold, Ivoclar-Vivadent, FL). 8 bridges of each series were veneered with A) Adoro heat&light curing, B) Adoro head/pressure curing C) Adoro heat&light curing with thermal conducting paste (all Ivoclar-Vivadent, FL) and D) a heat curing reference under N₂ atmosphere (BelleGlass, Girrbach, G). All FPDs were adhesively luted with Variolink2/Syntac classic (Ivoclar-Vivadent, FL). After thermal cycling and mechanical loading (TCML; 6000 thermal cycles [5°C/55°C], 1.2x10⁶ mastication cycles [50N]) fracture strengths (UTM 1446; Zwick; v=1mm/min) of each series were determined. Statistical analysis: Mann-Whitney U test (p=0.05). Results:

fracture force [N]	Adoro LC	Adoro HP	Adoro LC paste	Belleglass
Median	1555	1051	1701	1150
25 % percentile	1219	818	1099	1063
75 % percentile	1855	1240	2046	1304

Conclusion: The lowest fracture resistance was found for the heat curing Adoro HP and the reference material Belleglass. The light curing veneering showed the highest median fracture force and the heat conducting paste slightly-but not significantly- improved the material properties. The different polymerisation conditions influenced the fracture resistance of the restorations.

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