Objectives: A mathematical study was done to analyze the cuspal flexure of Jantarat et al. (J Dent 29:75-82, 2001) in vitro model. Methods: Independent Variables 1) Cuspal Angulations [Alpha 10, 30, 60°] 2) Tooth-Force Orientation [Beta 0, 3°] 3) Depth of Remaining Tooth Structure a) Intact tooth [0mm] b) MOD preparation [5mm] c) Endodontic preparation [10mm] 4) Total Applied Vertical Force [F100N; 50NperCusp ] Dependent Variables 1) Lateral Force Vector [LFV (N)] 2) Moment Arm [L (mm)] 3) Bending Moment [M (N-mm)]. The derived formulas were: LFV=[Cos (Alpha)] / F50N Depth=[r4.75mm/Cos (Alpha)] + [Tooth Depth] L=Depth x [Sin (Alpha)] M=LFV x L Results: The model system revealed significant variation of M-values due to the Alpha - & Beta-variables. Alpha 60°/Beta 0°: demonstrated the highest range of M-values: 205.0 N-mm (intact tooth) to 422.2 N-mm (endodontic preparation) with Alpha 10,30° at lower levels. Beta 3°-orientation produced significant M-value differences between cusps across all Alpha 10, 30, 60°-groupings. Conclusions: This investigation corroborated Jantarat et al. (2001) findings but suggest that the Alpha-variable & Alpha-/Beta-variable interactions contributed significant uncontrolled variability to cuspal bending behavior.

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