Adhesive luting of indirect restorations

Purpose: To describe the potential of adhesive luting procedures with respe ct to (1) material characteristics and classifications, (2) film thickness, (3) overhang control, (4) bonding to different inlay materials, (5) adhesi on to tooth substrates and the problem of hypersensitivities, (6) wear of l uting composites, and (7) clinical performance. Materials and Methods: A li terature review of relevant studies of various in vitro and in vivo studies enables an overview of possibilities and limitations of adhesively luted i ndirect restorations. Results: (1) Resin-based composites are the material of choice for adhesive luting. Both material properties and wear behavior o f fine particle hybrid-type resin-based composites are superior to other ma terials. The use of compomers is questionable due to hygroscopic expansion and possible crack formation as proven for IFS Empress caps in vitro and in vivo. (2) Recent luting cements exhibit excellent flow characteristics wit h mean film thicknesses ranging between 8 mum and 21 mum. The ultrasonic in sertion technique is recommended for viscous luting composites or conventio nal restorative composites utilizing their thixotropic properties. (3) For successful overhang control, good fit of the restoration (during luting) an d high radiopacity of the cement (after luting) are indispensable. Overhang control is estimated easier when the ultrasonic insertion technique is app lied. (4) The pre-treatments of ceramic inlays using hydrofluoric acid or s ilica coating result in effective bonding; for pre-treatment of resin-based composite inlays, silica coating is promising as well. (5) Bonding to enam el and dentin is proven clinically acceptable, but it should be performed w ith multi-step systems providing separate primers and bonding agents produc ing a perfect internal seal with almost no hypersensitivities. Dual-cured m ulti-step bonding agents provide the most promising potential. (6) The visc osity and filler content of the resin composite used for luting does not in fluence the wear characteristics within the marginal luting area in vivo. H owever, the ultrasonic insertion technique involving high viscosity materia ls provides enhanced handling characteristics for luting of tooth-colored i nlays. (7) Clinical results with tooth-colored inlays and veneers are promi sing over periods of up to 10 yrs, including use in severely destroyed teet h.