Reports on the ADI Team Congress 2011
Thursday 14 - Friday 15 April
Manchester Central Convention Complex
Petersfield, Manchester M2 3GX
Implant papilla management in the aesthetic zone
Speaker: Professor Joseph Kan DDS MS – USA
Reported by Koray Feran
Three patients had existing implants and were due to have a failing tooth next to one of these implants replaced. A fourth patient had two adjacent failing teeth. In such cases, Dr Kan stated that a lot of the papilla was a common occurrence that was normally managed by creating long dental contacts or some form of attempted surgical regeneration of the papilla.
Dr Kan admitted that the best surgical technique for predictable replacement of the missing papilla was the CS5 procedure, or more commonly known as the latest version of Adobe Photoshop.
There was a ripple of relieved laughter throughout the audience, all of us secretly reassured that our esteemed colleague with an international reputation for papilla management reassured us "in his humble opinion" that it actually could not be done predictably.
But since we still have to deal with these cases on a day-to-day basis, Dr Kan then outlined principles of treatment planning, concentrating on the level of bone present around the existing teeth and implants prior to making clinical treatment decisions.
The first question was how far apical will bone normally present on the facial aspect of existing teeth. Gargiulo’s 1967 paper is still an often quoted scientific study on the histological measurements of the attachment apparatus around natural healthy teeth, where the average distance of the gingival margin to the bone was 3 mm. The second was Kois’s clinical study on bone sounding on anaesthetised patients that showed that the attachment level could be essentially categorised into three subpopulations, high, normal and low. The normal group was in the 3 mm range found by Gargiulo’s average. The low group (where the distance between gingival margin and bone is increased) is associated with greater instability and susceptibility to recession. Tarnow's seminal paper on interproximal bone crest to contact point distances showed that distance exceeding 5 mm would result in lack of predictable papilla. Kois reported that interproximally this distance is approximately 4.5 mm with healthy teeth.
Dr Kan then questioned why the distance between bone and gingival crest was greater interproximally than facially. He explained that there were four main factors that determined the presence and shape of the papilla and outlined what these were are using the analogy of the behaviour of a beanbag to demonstrate how papillae behave.
Bone level - this is already discussed above.
Embrasure space created by the adjacent teeth - the supporting curvature of adjacent teeth is necessary to maintain the papillary point. Dr Kan analogised this to 2 people sitting back-to-back on a beanbag and likened the extraction of one of the teeth as one of these people getting up off the beanbag, leading to a slump in its shape. The interproximal papilla then behaves more like a facial papilla such that the tissue depth is reduced from the normal 4.5 to 5 mm distance to closer to the facial 3 mm distance, leading to diminution in papillary bulk and height.
However, Dr Kan also stated that this is not true in all cases and biotype was a third factor that also determined by how much this papillary slump actually occurred. Sadly, the thick biotype required to prevent the slump was only found in about one in five patients.
The fourth factor is the actual dimensions of the biologic width which also varies from patient to patient.
Dr Kan then returned to the beanbag analogy, using the floor of the bone and the people sitting on it back-to-back as the dental units supporting the papilla. The biotype was analogised by the quality of the beanbag cover (better quality less slump) where is the biotype was analogised by the quantity of filler (more filler less slump).
Recognition of these four factors and addressing them appropriately are the keys to risk management when dealing with such patients. The trillion dollar question was whether when the person that had got of the beanbag comes back to sit down, the papilla reformed.
Dr Kan reiterated that usually the presence of the papilla around a single implant is maintained by the interproximal bone levels of the adjacent teeth and maintaining an interproximal bone crest around an implant that is consistently coronal to the implant platform was extremely difficult. He also stated that the labial distance of the bone from the gingival margin around an implant was fractionally greater than that the natural teeth, 3.6 mm compared to 3 mm on average.
He stated that simply replacing the embrasure may not be sufficient to push the papilla back into its original position. If everything is favourable, the bone is insufficient height and quality and the biotype sufficient quality then the papilla could usually, on the whole, be predictably reshaped. However with a slightly less favourable biotype and also to the additional tendency for there to be an amount of bone loss associated with the trauma of extraction, implant placement and possibly bone augmentation, some interproximal bone resorption and remodelling was likely. He stated that tissue loss as a result of narrow biologic width and thin biotype coupled with bone loss as a result of surgical intervention could accumulate to create papilla loss.
The next scenario involved the loss of the actual tooth responsible for maintaining the papilla when adjacent implant was already present. Thin interproximal bone would automatically be lost soon after the tooth is extracted. Even immediate implant placement was inadequate to maintain this bone and site-specific implant designs have proved unsuccessful in the past. The interproximal bone level would automatically stabilise at the level already present on the adjacent implant, leading to loss of interproximal bone height and consequently papilla height.
Dr Kan soberingly then informed us that the orthodontic extrusion that many of us have prescribed to our patients in order to develop sites where teeth are to be extracted was mainly only effective on the facial aspect of the bone and had very little if any influence on the interproximal bone levels achieved post-orthodontics. He questioned whether such orthodontics to develop or maintain interproximal papillae was worth the time and money in many cases.
Dr Kan then suggested that whilst platform switching or abutment connection design may play a role in the maintenance of interproximal bone height coronal to the implant platform, it is by no means consistent and implant design alone was insufficient to counteract the other factors outlined above in the maintenance of hard and soft tissue topography. Multiple factors play a role in the maintenance of inter-implant and interdental hard and soft tissue contour and all of them need to be diagnosed and addressed for the optimum result.
It became obvious that the literature did not support consistent papilla maintenance between two adjacent implants since much of the required interproximal bone support between two adjacent implants tends to be lost with subsequent loss of papillae.
Dr Kan then discussed the options for maintaining submerged roots within the alveolus and adjacent implants to take full advantage of their attachment mechanism and their ability to sustain the interproximal existing bone. This of course is only viable if there is no infection or pathological process associated with the entire root length. He also touched on the possibility of utilising small slivers of remaining dentine and periodontal attachment on the aspect where maintenance of papilla is most crucial. He highlighted the fact that bone still managed to grow between the implant surface and the cut surface of the dentine sliver in the absence of any infection and mobility rather than dentine being left directly against an exposed implant surface.
He also acknowledged that if interproximal bone levels were correct, augmentation of absent labial bone was much more predictable and that the replacement of labial bone is much more predictable the replacement of interproximal bone.
On the subject of timing, Dr Kan acknowledged that immediate placement predictably gave results with the minimum tissue change compared to delayed or immediate delayed approaches and should be utilised where possible with good planning to ensure optimal tissue support.
This excellent lecture was effective at highlighting basic principles of interproximal tissue maintenance in detail with good scientific backup and relevant clinical cases to highlight shortcomings and benefits of various clinical procedures.