AUGUSTA, Maine — Nearly a year after high-profile child deaths placed renewed attention on Maine’s child welfare system, lawmakers growing impatient with the state raised the idea of gaining access to confidential case files to inform overhaul efforts.Much of the discussion at a legislative hearing on Wednesday revolved around whether a watchdog committee should seek access to depersonalized case records from the Office of Child and Family Services that are now used by nonpartisan investigators to gain a better understanding of potential missteps taken in child welfare cases. The new inquiries from frustrated lawmakers could put them on a collision course with the state, which signaled on Wednesday that it was wary of opening up confidential records to scrutiny.