"SANTIAGO (Reuters) - A conservative billionaire is the front-runner in Chiles presidential election Sunday but is seen needing a run-off to break two decades of center-left rule since the end of Augusto Pinochets dictatorship. World Center-right businessman Sebastian Pinera, who has vowed to build on prudent fiscal policies that have made Chile the worlds No. 1 copper producer and a regional model of stability, leads by a least 10 points in opinion polls before the first presidential vote since Pinochet died in 2006. But he is expected to fall short of the outright majority needed for election, setting up a January 17 run-off against Eduardo Frei, a former president from the splintered ruling coalition who is running second. Polls show Pinera winning a runoff by at least 6 points. It would be the first presidential election victory for the Chilean right in half a century, and a rare win in a region dominated by leftist governments.