Multidisciplinary treatment: one plan, and who holds it

Across separate fields, the same pattern turns up. In the survival literature for root canal treatment, four conditions improved the odds of the tooth still being there years later, and a crown restoration placed afterwards ranked first among them, ahead of tooth type and everything else examined.^[1] In the veneer literature, whether the bond sits on enamel or on exposed dentine separates about 99% survival from about 91%, and success from 99% to 74%.^[2] Both are restorative variables settled by decisions taken earlier.

That is the argument for planning from the restoration backwards, and it is a clinical argument rather than an organisational preference. The stage that most determines whether the work lasts is usually the last one performed, which means every stage before it should be carried out to a specification the last one supplied.

Between orthodontics and restorative work, the join is the final tooth position: aligned to the arch, or aligned to where the veneers need the teeth to be, which are not always the same target. Between periodontics and restorative work, it is the tissue level: the margin the surgery finishes at has to be the margin the restoration can seal to. Between implant surgery and restorative work, it is the emergence: an implant is placed for years of loading, and the crown coming out of it has to look like a tooth from the front.

None of these are difficult questions once they are asked. They are simply questions that belong to two people at once, and therefore get asked by nobody unless somebody owns the join. That ownership is what the word coordination is doing in this description, and it is a job rather than a courtesy.

A back tooth was lost some years ago and nothing was done about it. The teeth on either side have tipped and drifted into the space, and the tooth above has over-erupted downwards into it. From the front there is still a gap, so an implant appears to be the missing piece. Measured, the space is narrower than the crown that should go there, and shorter in height than the restoration needs.

So the sequence inverts. The restorative plan supplies the number: how wide and how tall the space has to be for a crown that matches its neighbours and meets the opposing tooth correctly. The orthodontist uprights the tilted teeth and re-opens the space to that dimension, and where the over-erupted tooth is the problem it is intruded rather than ground down, which keeps its structure intact. Only then is the implant placed, into a site now shaped for the restoration rather than the other way round.

A tooth does not fail in isolation. A heavily worn front tooth is usually reporting on how the back teeth meet. A tooth that keeps losing restorations at the margin may be sitting in a periodontally compromised site, which is staged and graded on its own terms before anything is rebuilt on it.^[3] Treating the complaint without reading the context produces work that is technically sound and then fails for a reason that was visible the whole time.