Connecting Natural Teeth and Dental Implants: New Techniques?

Natural teeth- biology, PDL, flex, non-ridged Implant -bio-mechanical aspects, no PDL, no flex, ridged Not a great idea....you can attempt to try all the recommendations in the literature, however the chances of having the tooth or the implant fail can be high

The use of fpds cemented with a soft cement over copings cemented with a hard cement atop natural teeth and usually no coping on the implant, unless needed. This has been working very well for five decades.

Numerous reports demonstrate a natural tooth may be splinted to an implant. However, when possible, make implant restorations separate from the teeth- for primarily biologic reasons ( not biomechanic). When teeth are splinted to an implant (or tooth), the pontic acts as a plaque resevoir and decay affects the tooth 20 to 25% of the time within 10 years. In addition, crowning the natural tooth increases the risk of endodontics (and so does the decay). Therefore, do not crown the natural tooth and splint it to an implant. However, if this is necessary, the risks of the prosthesis may be reduced when: 1. Use a posterior tooth with no lateral force on the prosthesis. The majority of the movement difference between teeth and implants is with lateral forces. Hence anterior guidance or canine protected occlusion with no lateral forces on the posterior teeth make the restoration less at risk. 2. Make a one piece bridge with no precision or semi precision attachment. Solid connectors decrease the risk of tooth intrusion. 3. Use hard cement on the natural tooth. The tooth can not intrude from a one piece casting, unless the cement seal breaks. Limit the pontic distance to the size of 1 or 2 premolars. Cement seals will break more often with larger forces and longer spans between abutments

Read 30 years of Kirsch IMZ implant system ( from germany) literature. I have hundreds of cases tying natural teeth to implants and 25 years IMZ experience to validate the thesis and findings of the IMZ literature that is is doable and workable, long term. But that was before anti-rotational implant abutment connections were on the market....and before perfected by Kirsch Camlog Implant System ( from germany via Henry Schein co.) internal connection patent. But, with modern implants, such as with Camlog Connection....free-standing implants are preferred. No reason to connect to teeth at this time in history. Perio-prosthetically desirable not to! Why bridge at all when single tooth, tooth for tooth placement is possible and viable now.

Carl Misch expressed it perfectly. I have splinted natural teeth to implants for over 25 years ( when necessary)without a problem. If anything the implants have increased the longevity of the natural teeth that needed splinting to begin with.

I have splinted teeth to implants (only when no other option) and have not had a tooth or implant fail over 10 years. I have abour 15 patients treated this way to date. If you look at the photos in the article, several things come to mind. In the intrusion case, having three implants with a tooth between them is false conservation. That tooth should have been introduced to cold steel and sunshine then a fixed bridge fabricated totally on implants. The other case photos show an implant as a pier abutment. Not sure I'd connect the anterior tooth to the tooth/implant complex since biomechanically there would be extraction force on the anterior (#5?) natural tooth. I would make a three unit FPD from 2-4(implant) with a single crown on #5. This was an interesting article and gives more food for thought regarding this malaligned but doable treatment option.

Splinting natural teeth to implants can be predictable over a long period of time. I have been doing it for over 35 year. However certain principals must be followed. Do not connect to an endo treated tooth. Do not connect to a tooth that has any degree of mobility. Do not connect to a tooth that has a poor crown root ratio. There should not be more that one pontic. Another idea is to make a gold coping on the natural tooth cemented with a permanent fixed cement and make the bridge retrievable using temporary cement. The gold coping helps prevent recurrent decay on the natural tooth.

If this is such a good idea, why is it that NONE of the implant manufacturers sanction this?

About the cements, which ones are recommended? There was a mention of hard and soft cements, but no type of cement has been mentioned.

I would definitely consider using an implant-tooth bridge where there is no other option. If the prognosis of the tooth is not too long-term, I would consider electively replacing the tooth with an implant to achieve a better long-term progosis. At times patient who have three missing adjacent teeth and wish a bridge, then here I would definitely use an implant in the middle as an abutment. Again alway increasing the thickness and rigidity of the bridge.

There are two approaches to the problem. If a patient wants to have good masticatory function and has powerful antagonists (with intact periodont), implant-supported tooth should be connected to the adjacent one by ANY means (to create balanced occlusion). In my mind, cantilevers are harmful even for splinted teeth. If a patient wants to have just cosmetic function or has partial or complete dentures as antagonist, eats only “soft” food, we can leave implant-supported construction unconnected.

Dr. Deol, The hard cements are ZnPO4 and Glass Ionomers. The soft cements are the ZOE's and polycarboxylates. I hope this helps.

Connecting the natural teeth to a dental implant would be a great mistake.Believe me, I know.I have seen the consequences.

Occasionally there is significant benefit to splinting a natural tooth to an implant such as bypassing a risky surgery at the site of the mental foramen or when other surgeries are complex or contraindicated. There is considerable empirical as well as published evidence as Dr. K has alluded to, showing that this is viable when done under considered protocol. The protocol which I adopt is: • The implant abutment should be of substantial size and should be placed in type II bone to best withstand the increase in shear forces that can arise from this type of hybrid bridge system. • The pontic should have a short span, preferably only a single tooth, to minimize torque forces on the abutments. • The natural root abutment should have good stability, preferably with no mobility and the tooth should preferably be multi-rooted to minimize tooth displacement. • Both abutment connectors should have a rigid connector design. Nonrigid attachments should be avoided as they are associated with a greater incidence of root intrusion. • If telescopes or copings are used, avoid temporary cements; in particular, avoid the no-cement coping technique, as loss or absence of a rigid connection will induce the highest incidence of intrusion. • Use highly retentive cements with superior design features for retentive preparation at the abutment to resist cementation failure. • Eliminate or minimize unbalanced tooth contacts in excursive movements as well as in centric. • Consider bruxism as a risk factor; if present, manage bruxism with an anti-bruxism splint, preferably placed on the arch that contains the bridge.

What part of the equation that an implant is not a tooth that individuals do not understand. Alex Kirsch developed an Intermobile Element to attempt to solve the problem of implant to tooth connection. Guess what??? The Delrin ring IME always failed with use and then the neck of the implant fractured. It is counterintiative to believe that a rigidly fixed object [implant] connected to a non rigid object [tooth] is a mechanically sound system. Cements fail when they are subjected to shear forces. No cement will stand up to a situation where there is a shear force applied to a micromobile crown attatched to a rigid implant. In my opinion there is no justification to tie a rigid implant to a non rigid tooth. I have been involved with modern impant systems since 1979/1980 and have not seen a study that would support the connection of implant born restorations to natural teeth. There was a comment to produce a large overbuilt crown in order to allow attachment to an implant - have we forgotten our basic principles of biological width zones and occlusal overload?

Connecting of the implant to the natural teeth may cause a serious damage to the implant , and movement of the natural teeth in the range of PDL ultimately cause a greate bone loss around the implant .Many times requests and insisting of the patients may lead to this great mistake. Dr. Ali Hossein Mesgarzadeh Tabriz /Iran

Dr. Hughes, thanks for the input on the cements. I actually have a case in planning with Implant#12 and #13.14 missing with sinus floor almost to the level of crest on a 86 yr old patient. #15 is intact but endo treated. I was planning a coping on #15 with FPD from #12-15 with a small occlusal table and hope for the best. We will discuss the prognosis with the patient. In my opinion, even extraction of #15 and an implant in that area with poor bone quality for a 4 unit bridge may not be a good choice either. Comments on that are appreciated.

Dr. Deol, The things I would carefully evaluate are the following; patients ability to maintain oral hygeine, occlusal parafunction (check out Eugene McCoy's paper on dental compresson syndrome, this really open my eyes and has kept my backside out of trouble, fractures, mobility, periodontal involvement. I also recommend that the occlusion be that of ultra lite, if any contact at all, Take into consideration the size of the patient, patient's neck and tone of the muscles of mastication. I also recommend that when you deliver the case that you rehearst the delivery. Also cement the coping and place the bridge on top but line the bridge with vaseline and have the patient bite on an orange wood stick or moist cotton rool. Remove the bridge and cement the bridge after cleaning with the soft cement.

Unfortunally, as many other topics in implantology, I still havent found any well designed clinical trial that could answer that question. There are lots of case series studies that alone, should not be taken into account when we make an evidence-based clinical decision. So, the best thing to do is to listen as many opinions you can and try to make your patient knows all the limitations of that approach before start treatment.

Perhaps, the most frequent situation that forced us to think about the necessity of splinting of implants and teeth is the inability to place implant in the area of mental foramen.The decision depends on well-known factors,including number of implants,potential BIC,extension of cantilever,stability and periodontal health of canine,control over the parafunctions etc.But, in my opinion, the most important thing is the occlusal pattern at the time of lateral movement... When we have canine guidance the implant-supported prosthesis with cantilever( first premolar ) is safe. On the other hand , when the group function is obvious, in some cases we can consider the rigid splinting of implants( at least two acceptable implants) with canine. All the best...

Dr Deol: the hard cement are the glass ionomers we used in our regular crown and bridge procedures (like Fuji etc). For implant restorations the only one to use is a eugenol free acrylic/urethane base cement. The best is without a doubt IMPLATEMP, that gives excellent mechanical strengh for reliable prosthesis retention, and trouble free removal, as well as long term performance when desire. It does not adhere to soft tisssue, so it's very easy to remove, so I know that no cement it's left in the critical area of the implant abutment margin. This amazing cement was developed by my mentor Renzo C. Casellini. If you would like to order call 1 800-SWISS-123 Believe me, you will never use anything else.