Expect the unexpected
In the last article, I described the sub-epithelial connective tissue graft that was carried out in order to increase the soft tissue bulk labial to Patient NC’s implants. A healing period of several weeks was allowed, which was uneventful, and figure one shows a good increase in volume as compared with the situation prior to the graft, seen in figure two.
Now we are ready to carry out what is known as second-stage surgery, where the implants are uncovered and temporary healing abutments placed. This provides a further opportunity to increase soft tissue bulk, labial to the implants and in the aesthetic zone, my preferred technique is to make a semi-circular incision around the palatal part of the abutment. This allows me to bring some of the palatal tissue across to the buccal.
The cover screws are located and removed, being replaced with the healing abutments. In NC’s case, we used a flared 4mm height abutment, which was able to support the soft tissue that was reflected from the palatal side (Fig 3). The provisional bridge was adjusted and re-bonded. I must add that by this stage, the bridge wings were significantly worn, lacking retention and as a result required regular re-bonding. NC and I were now very keen to get to the next stage.
Bearing in mind that we were planning provisional crowns, I did not need to wait for full soft tissue healing, and so planned the impressions for two weeks later and figure four shows the healing abutments at this stage.
The healing abutments were removed and revealed an excellent soft tissue collar with a view down into the internal conus of the Astra Tech implants (Fig 5). Pick-up impression copings were attached (Fig 6) and a rigid stock tray customised so that the guide pins of the copings were protruding through the holes prepared (Fig 7).
An impression was taken using Impregum (3M ESPE), this material providing the rigidity that is so important for implant work (Fig 8), the guide pins unscrewed (Fig 9) and the impression tray removed (Fig 10). The healing abutments were re-attached and the bridge re-bonded.
There are many materials, techniques and approaches for provisional restorations on implants, especially bearing in mind the digital and technical revolution that we are witnessing, and on discussion with Sandy Littlejohn (DTS International, Scotland), he suggested a new material that they were using for provisional restorations on teeth, called Telio-Cad, which is an acrylate polymer that uses CAD/CAM milling technology. We discussed this with our patient NC and, in the interests of bringing the reader of this case series the latest in technology, we decided to go with this… a decision that was going to come back to bite us fairly soon.
Knowing that we may be pushing the limits with this new material, the crowns were linked together for added strength, and all looked very nice on the model (Figs 11-13). The provisional bridge and healing abutments were removed for the last time (hopefully), and the linked provisional crowns tried in.
As can be seen, they are screw-retained as opposed to cement-retained. This is very much a hot topic in implant dentistry as screw-retention is becoming more widely recommended, following many years of cemented restorations being the restoration of choice. The reason for this seems to be the increasing desire for predictable retrievability and the prevalence of peri-implantitis which, according to some scientific articles, can be attributed to up to 70 per cent of this disease. I now am placing increasing numbers of screw-retained restorations.
The crowns were tried in and fitted (Figs14-17), with the screws being torqued to 25Ncm using an electronic torque driver (NSK), and the access holes sealed with PTFE tape and temporary filling material (Figs 18 and 19).
The appearance of these provisional crowns was excellent and NC was delighted to finally have some fixed teeth. Figures 20, 21 and 22 show the provisional crowns in place and, being linked, the accessibility of an interdental brush was important to establish (Fig 23).
NC was travelling to France the following day for the summer, and everyone, the team at Dental fx, DTS and not to mention our patient, were extremely happy with our work and we all gave ourselves a big pat on the back, not knowing the disaster that was about to strike.
A few weeks passed and I was tidying up some loose ends, finishing off some key treatment plans prior to my annual vacation two days later, when I received a distress call from NC. As you will read in his article, he was sitting on his terrace enjoying the sun, the view, some appellation contrólée…. and an olive stone. A ’crack’ was felt and the provisional crowns had loosened, falling out soon after.
I could not understand what had actually happened and I had to turn detective to establish the cause. It is not unheard of for a screw-retained crown to loosen, but they generally feel loose for some time before actually coming out, but for two linked screw-retained crowns to suddenly fall out, something more serious clearly had happened.
Next on my list of possibilities was a screw fracture, something that I seem to spend more time these days having to deal with. But, for two screws to fracture in a relatively low stress situation? The mystery deepened. Implant fracture was also unlikely with these particular implants.
NC sent a picture of the crowns to me – the advantage of a smartphone! I was unable to see any part of the screws inside the crowns in the implant/abutment interface region, there was no sign of them, so screw fracture was ruled out.
I then assumed that the part of the provisional crowns that actually engaged inside the internal conus of the implant had fractured and sheared off, leaving the screws inside the implants, and most importantly intact.
There are many messages and morals to this story, such as using restorative materials that have been tried and tested in these situations and having a spare provisional restoration available, being among them. But just as important was the use of an implant system that is widely used and has long-term documented success rates.
There are so many implant systems out there nowadays, all vying for our business, and while my remit does not allow me to compare or recommend any particular implant, I would like the reader to just consider which implants they are using and how easy it would be to source a dental clinician in another part of the country, or world, who can help one of their patients out, by having the correct equipment, drivers and components. It was only because I was using one of the main implant systems, that I was able to facilitate the management of this emergency.
Because we had used this particular implant, I contacted the company and my colleagues at Astra Tech in the UK, sourced an experienced user of their system near NC at Perpignon, France, who was able to see NC immediately and help us out. He reported that my hunch of the fractured abutment interface was indeed correct. He removed the screws, which had not fractured, and the fragments of Telio-Cad from within the implants, and attached healing abutments.
We had DTS make some new crowns, using acrylic on titanium temporary cylinders and these were sent to France, so that within two days, our ’French dentist in shining armor’ was able to fit the new provisonal crowns without NC needing to get on a flight home.
So, in summary, my grateful thanks go to the dentist in France, Astra Tech, DTS and FedEx, not to mention a very understanding patient. It was certainly an interesting lesson to learn.
As I write, all appears well, and in the next article we shall have a look at the new provisionals and move on to the definitive crowns.
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
The French connection
As he enters the home straight in his journey towards a working pair of front teeth, Patient NC describes a holiday experience to forget…
So, the day has arrived. And what a blessed day it is. I have two perfect, front teeth that look like they belong there and work: they actually work! No more tearing into food with the side of my mouth, no more covering up the smile with a hand to protect the innocent from the crooked gnashers holding on to my gum by the skin of… well, you all know the story.
But the final phase – well almost – has not, you will be surprised to learn, been without incident. Nothing in this story could ever have been straightforward. My fault, not that of the extraordinary people whose combined skill has brought about an amazing result.
What happened this time, I hear you groan? Well…let’s start at the beginning. The good Dr Jacobs removes the healing caps – painlessly – and in go the new, if temporary, crowns that have been built by the talented craftsmen at DTS.
As an aside, if you ever want a glimpse of the future, you simply must take a trip to the DTS laboratory in Glasgow’s East End – Duke Street, to be precise. The equipment and materials they are using there will blow you away. I kid you not.
However, back to my tale. In go the temporaries and I am thrilled beyond all reason. Because, 1. I can throw away the bridge that is now so used it holds for all of three days before coming apart, 2. I can stop being terrified of it dropping out during meetings, 3. I can now go to France and eat as much crusty baguette as I like with my TWO FRONT TEETH!
Ooh, La, La! Not quite! Now, I’ve been warned to be careful with the new boys: “Take it easy, don’t bite on anything ridiculously hard,” I’m told. But non. I have a few too many glasses of plonk and savage an olive I think is hollow. Not good. I feel something go and, to my utter despair, it’s the temporary crown. The sheer force of the jaw (I’d no idea it could generate that much pressure) has snapped the teeth at the screw points.
And where am I? La Belle France. What do I not have? Two front teeth, any relationship at all with my darling wife, and finally and most importantly, a dental lab and a dentist. Catastrophe!
Well, not to the boys from DTS or my NBF (new best friend), Stephen Jacobs. A surgeon in Perpignan (a stunning place by the way) is located. An appointment is booked. New teeth are made in 24 HOURS and all the necessary supporting materials shipped out to France for next day delivery.
Now, as everyone knows, the health service in France is manifique. So, within two hours of the teeth arriving at the surgery, I’m in the chair and out in half an hour back out into the sunshine with my face returned to its socialising best. Thrilled? I could have danced naked down the Champs–Élysées. On second thoughts, I’ll spare everyone that. But you get the picture.
Today, I sit with my mouth restored. I only now have to get the final crowns set in place after a little colour work has been done.
It has been the most amazing journey. I truly did not expect to reach this point. And it is all down the extraordinary talent of Stephen Jacobs and his team in Bearsden and the support of the amazing people at DTS. Merci boucoup.
Now, where’s that crusty baguette?