Bare aluminum baffles are adapted for resist stripping chambers and include an outer aluminum oxide layer, which can be a native aluminum oxide layer or a layer formed by chemically treating a new or used bare aluminum baffle to form a thin outer aluminum oxide layer. Dental compositions including such dental fillers can be useful for delivering ions to the oral environment. Moreover, the sacrificial support structures may be electrically resistive. This corresponds to a antireflective structure having a pitch of a wavelength or less in the ultraviolet band at the time when ultraviolet light is used as incident light. The resulting ball has high resiliency along with a soft feel.