Setting the standard
In the last issue we had atraumatically extracted both upper central incisor tooth roots, and having fitted the adhesive bridge, our patient NC, was delighted with the result. The sockets were noted to be healing well over the following weeks (Figs ı, 2 and 3), however the adhesive bridge did require re-bonding on a few occasions.
I find that when using an adhesive bridge in this situation, particularly where the lateral incisors are being used to replace both centrals, the lack of surface area for the palatal wings can predispose to de-bonding of the bridge. On reflection, using metal wings in a classic ‘Rochette bridge’, may or may not have been less susceptible to de-bonding. However, in any such case, when educating and informing the patient of this possibility at the planning stages, they may be prepared to accept this compromise, rather than wear a partial denture. Our patient, NC, was very much a good case in point in this regard.
CBCT
Five weeks post-extraction, it was decided that a cone beam CT scan was justified in order to assess the bone volume for the proposed implants. I have been using cone beam scanning technology for several years, culminating with the acquisition of a CBCT machine (PaxDuo,Vatech-Ewoo) almost two years ago. Having an onsite CBCT machine at Dental fx has been a resounding success, improving the efficiency and service to the patients, not to mention our referring colleagues. The images generated, together with the software functionality, allow me to plan and assess implant cases with a huge amount of detail and predictability. We have found that we carry out far less bone grafting as a result.
On looking at the cross-sectional images of the two prospective implant sites, it can be seen that in the ıı position, the coronal half of the buccal plate is absent (Fig 4), while the 2ı would appear to have the bony socket intact (Fig 5). These findings are consistent with the direct inspection and sounding of the socket at the time of extraction. Also, bearing in mind that it is only weeks following extraction, the outline of the sockets can be clearly seen, and with adequate bone apico-palatal to the sockets, where the implants are planned to be positioned.
The placement of the implants was planned for a few weeks later, when sufficient soft tissue healing over the sockets had been obtained, and NC was informed that guided bone regeneration would be required, but that the implants could be placed at the same visit.
Implant placement
On the day of placement, following removal of the provisional bridge, NC was given a chlorhexidine (0.2 per cent) mouthwash for two minutes, after which infiltration local anaesthesia (articaine 4 per cent, ı:ı00,000 adrenaline) was administered.
A mucoperiosteal incision was made, palatal to the crest of the ridge, with vertical relieving incisions from just distal to the buccal gingival zenith of the lateral incisors, extended beyond the muco-gingival junction. Reflection of the flap revealed a mass of granulation tissue in the ıı site, that once curetted left a dehiscence defect of approximately 5mm, the contralateral site, at 2ı, having better bone morphology, but nevertheless with a smaller crestal defect (Fig 6). These findings were once again consistent with the cross sectional images seen on the CT scan.
At this stage, in view of the augmentation of the site that would be required, periosteal relieving incisions were made (Fig 7). I carry this out at this stage, due to the vascularity of the periosteum, allowing any bleeding to have subsided by the time the biomaterials would be required and handled.
It was decided that, with all the information to hand and the fact that the implants were to be positioned where the original tooth roots were, from the mesio-distal perspective, a surgical guide was not required.
The osteotomies were prepared, starting with a small round bur introduced towards the palatal wall of the socket, similar to the technique of placing into immediate extraction sockets. The 2mm twist drill was used and prepared to a depth of ı3mm, with care taken to ensure that the long axis emerged between the cingulum and incisal edges of the two teeth to be replaced. The osteotomies were enlarged using the 3.2mm twist drill (Figs 8 and 9) and finally the conical drill (Fig ı0), which is part of the implant system being used, completed the site preparation (Fig ıı).
Two 4.5mm diameter, ı3mm long implants (Fig ı2), were placed (AstraTech, Dentsply) by hand (Fig ı3), with the insertion torques then being measured at ı8Ncm using an electronic torque controller (NSK, Japan). Implant stiffness was measured using a resonance frequency machine (Osstell ISQ, Goteborg, Sweden), the ISQ (implant stability quotient) values being 65 for the ıı and 7ı for the 2ı implants. Cover screws were then attached to the implants.
Care was taken to ensure that the depth of placement was optimal, the implant platform being 2-3mm apical to the cemento-enamel junction of the adjacent teeth.
It may strike some that these implants have been placed with remarkably low implant insertion torques. This subject is one of the current hot topics in implant dentistry.
However, some recent unpublished work has shown that low insertion torque using a fluoride modified textured implant surface produces a flatter implant stability time lineı, a study that I, with a co-worker, have modified and are currently working on.
A personal view of mine is that many implants these days are being placed at very high insertion torques, sometimes in excess of 50Ncm, something that I feel cannot be good for osseous healing, and possibly slowing down the osseointegration process, if one looks at the healing/integration graphs that are produced when primary stability is investigated as a variable.
Further, in a study accepted for publication, there has been shown a 95.5 per cent implant survival rate on 68 immediately placed and provisionalised implants in extraction sockets over a follow-up period up to nine years, where the insertion torque was ≤25Ncmı.
Guided bone regeneration
As can be seen in Figures ı4 and ı5, a large defect revealed the microthreads on the conical shaped part of the ıı implant being uncovered by bone, with a smaller defect on the 2ı implant, where several coronal microthreads were exposed.
Some autogenous bone, that was collected on the drill flutes during the osteotomy preparation, was placed directly on the implant surface, with a deproteinated bovine bone mineral xenograft (BioOss, Geistlich Biomaterials) layered on top of this. A collagen porcine membrane (BioGide, Geistlich Biomaterials) was placed in two layers, over the xenograft in order to protect it and create a bony healing compartment (Figs ı6, ı7 and ı8).
Closure was obtained using 5-0 Vicryl Rapide (Ethicon) sutures. This closure was tension free as a result of the periosteal relieving incisions referred to earlier. Further, the surgical site was relatively dry with minimal bleeding, because these scoring incisions were carried out near the beginning of the procedure (Fig ı9).
Post-operative instructions
Antibiotics and non-steroidal anti-inflammatories were prescribed, together with 0.2 per cent chlorhexidene mouthwashes. NC was advised to apply ice packs to the outside of the face, for the remainder of the day in order to reduce the swelling.
Initial healing was uneventful, except for the one occasion where NC was experiencing some fairly significant pain, three days following surgery. Post-operative pain is very unusual – I would actually say it was rare – following implant surgery, assuming that the correct analgesia is provided. So, to receive a telephone call on a Sunday afternoon, while I was at a
wedding, came somewhat as a surprise.
Advice, and more importantly, reassurance, was given over the phone and the pain very quickly settled completely, in fact by the following day NC was pain free. This highlights the importance of giving patients your contact details in case of any problems, even if it is only advice and reassurance that they require, it is an essential part of patient management.
NC was to be reviewed one week after surgery followed by a period of three to four months to allow osseo-integration and graft maturation. During this time the profile of the soft tissue was to be assessed in order to determine the next stages.
References
Barewal R, Implant stability in relation to insertion torque, EAO Congress 2010.
Norton MR, The Influence of Insertion Torque on Implant Survival in Immediately Placed and Restored Single-Tooth Implants, Accepted for publication, Int J Oral and Maxillofacial Implants.
About the author
Dental fx is based in Bearsden Glasgow and was founded by Dr Stephen Jacobs in 2006. Although dealing in all aspects of dentistry, Stephen has a special interest in implants and has been placing implants for more than 20 years.
Dental fx is a teaching centre for dentists and nurses interested in learning more about dental implants and to this end Stephen runs a number of courses throughout the year.
Please contact us for more information regarding the courses by emailing our course co-ordinator ator visit our web site http://www.dentalfx.co.uk
As painless as possible – the patient’s perspective
In my house, it is well known that I have the pain threshold of a sunburned three-year-old whose useless parents forgot to bring the calamine lotion. Man or mouse? Pass the cheese.
My plight is compounded when she who must be obeyed happens to be a former nursing sister, so reducing the prospects of a distress-easing cup of tea to below zero. It has to be clinically proven confirmation of my mortal coil departure before any form of gentle ministration is forthcoming. Getting the picture?
But I merely set the scene. You will have digested the science bit from the good Doctor Jacobs. So, when he describes a post-operative day of excruciating agony (I’m a journalist, I exaggerate professionally) as “some fairly significant pain”, I immediately suspect he and my other half of a clandestine conversation before I set out on this journey! The sympathy clearly lying with Dr Jacobs, of course.
At this point, I would also issue a public health warning. Regardless of how much oral pain you are in, never think salvation lies at the Southern General’s emergency GP clinic. Presenting dental pain to the hard-pressed team there elicits roughly the same response as asking the recently repossessed homeowner to discuss the merits of the banking profession! They really don’t want to know; a fact proven by the four and half hour wait before I finally gave up and fled into the night. Before I left, they did, however, give me – I suspect – a DFıı8 (or its modern equivalent) that certainly did for the pain… and nearly for me when I added a large Lagavulin to the mix to ensure blessed sleep.
Now, let’s get some perspective into this. The truth is that I WAS in some “fairly significant pain” for about ı8 hours, three days after the procedure. Bizarre and unexplained, I know.
Perhaps the reason it was so surprising was that I had been completely at ease during the actual procedure, thanks to the thorough explanation of what was to be done and excellent anaesthetic management. At no time was there any discomfort in the hour or so I was in the chair, probably longer than generally required because of the number of images being taken for your benefit! While orally more invasive than anything I have experienced, it was, in truth, not really arduous at all. Slightly nervy – then again I am – but simple and straightforward from the patient perspective.
What was remarkable was that there was no pain post-operatively from the site of the procedure and there was minimal bruising and swelling. The comprehensive post-operative guidance was exemplary and worked (my own outstanding contribution to medical science is to have devised an ingenious new cold pack to reduce swelling which I WILL patent, so don’t get any ideas: simply roll frozen peas into cling film, mold into a moustache shape, freeze and apply to the upper lip, replacing each one as it melts – a hell of a lot easier than trying to get an entire bag of frozen veg on your face… which, being a bit thick, I tried!).
The “worst”, I am told, is over and we are now on the last lap to my new teeth. The trials of the flying bridge (see last issue) and the discomfort of post-op are now behind me. Surely there is nothing more to come.
But wait: the editor has just shown me pictures of what was done inside my mouth while I wasn’t looking. That’s it, back to the whisky bottle…no wonder it bloody hurt!
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