• Inlays, onlays and endocrowns

    • Friday 19th May, 10:45 - 11:45
    • This lecture is presented by: Dr Christopher Orr
    • This session will take place in: Room 1

    • dentist, team

    Inlays, onlays and endocrowns – is it time to say goodbye to traditional posterior crown preparations?

    In today’s clinical practice, our patients routinely enjoy the benefits of the adhesive dentistry, which allows us to provide highly aesthetic restorations with minimal (or no) tooth preparation. Unfortunately, in posterior areas, this may not be strictly true.

    Inlays have been used as an alternative to a direct restoration to help in situations where creation of tight proximal contacts or management of composite polymerisation forces is difficult due to the size of the cavity. With recent improvements in direct composite, especially with bulk-filled composites, their use is diminishing.

    The opposite should be the case for onlays but unfortunately it is not the case. Many heavily filled posterior teeth require cuspal coverage to prevent fracture, especially after endodontic treatment. The traditional approach is to place a core buildup, possibly using a post for added retention, followed by a crown. This approach is hugely more invasive on a tooth which has already been extensively prepared. It may have been necessary in the era of zinc phosphate cement, but adhesive cementation makes many aspects of traditional resistance and retention significantly less important for today’s practitioners. Unfortunately, it is still widely practised.

    Onlays offer us a more conservative, more easily retrievable and aesthetic approach to the restoration of posterior teeth. Long-term research shows that they have a very similar longevity to traditional crowns over 15 years, with better retrievability in the event of endodontic complications. We have new generations of high-strength ceramics and user-friendly resin cements which greatly simplify the whole process.

    Endodontically treated posterior teeth can be restored with an endocrown – a larger version of an onlay, extended into the pulp chamber. These are less well-researched than onlays, but are showing promising results.

    If onlays really can do the same job as a traditional crown, with similar longevity, superior aesthetics and reduced invasiveness, why are we still preparing posterior teeth for crowns?

    Aims and objectives/Learning outcomes
    1. To review the invasiveness of preparations for different indirect posterior restorations;
    2. To discuss available materials for fabrication of inlays and onlays and the associated preparation designs and cementation materials
    3. To compare restoration longevity for different posterior restorations.


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Christopher Orr