From the Bioimplant website (www.Bioimplant.at):
Immediate individual Zirconia Dental Implant
by MD.DDS. Wolfgang Pirker
Univ.Prof.MD. Alfred Kocher
Vienna/Austria – Present dental implant strategies that work successfully in delayed implantology have serious limitations regarding functionality and esthetic outcome in immediate implantology.
The main reasons for these shortcomings are based on the fact that currently available dental implants are axially symmetric and made of titanium.
In fact, they resemble the natural root neither in form nor in color.
The lack of the correct fit has to be compensated by multiple complex additional treatments such as bone augmentation, guided tissue regeneration as well as gum plasty. These procedures are time consuming, not enough predictable, generally costly and cause in addition great strain to the patient.
One has to keep in mind that these multiple and highly invasive procedures serve only the purpose, to model the bone around an in fact ugly, simply because silver-colored and non-anatomical implant, in order to achieve at last a close to natural result. In other words these additional therapies are only necessary to fill and bridge the gap between bone and implant to counteract the atrophy of the non load bearing thin cortical bone and eventually prevent loss of hard and soft tissue.
The indication for conventional immediate dental implantation is therefore still strictly limited to a very low percentage of patients with single tooth loss. Furthermore, due to the high sophistication and risk of the procedures the results are extremely dependent on the skills and experience of the surgeon and the compliance of the patient, respectively. Hence, the outcome is hardly predictable and the treatment therefore not suitable for everyday general praxis.
In contrast to these complex and costly procedures, an exact fit and perfect esthetic outcome is simply and safely achieved, by taking advantage of the up to date principles of differentiated osseointegration, the use of Zirconia, a highly biocompatible implant material, combined with the preciseness of the latest CAD/CAM technology.
Compared to conventional implant strategies, the novel, individualized immediate Zirconia dental implant matches the extracted root both in form and color, respects not alter the underlying anatomy of the extraction socket and does not require at all any additional cost intensive and straining surgical interventions. This minimal invasive method enhances patient acceptance and maximizes functional as well esthetic outcome.
This most innovative approach is presented herein to a broad expert audience for discussion.
Deficiencies in immediate dental implantology
Rotationally symmetric titanium implants have stood the test of time for decades in delayed implantation with success rates of up to 98%. But conventional implants were originally constructed for insertion in healed jaw bones, and are primarily not really suited to be inserted into the irregular formed extraction socket.
Immediate implantation is – against the suggestion of some commercials and smaller studies – on no account a standard treatment, but does have a limited indication and requires experienced specialists. This is particularly true for the recently propagated immediate loading of single dental implants, which are currently, used exclusively in front teeth. In the maxillary molar region the chewing forces, the root anatomy as well as the low bone quantity and quality prohibits immediate implants at the very most instances.
Especially the term “immediate loading” is highly misleading, not only for patients, but also for general dentists. At the present time it is absolutely impossible to load a single implant with occlusional loads immediately and therefore to gain an immediate full rehabilitation of chewing function. The implant is barely stable enough to withstand reduced chewing forces without contact to neighboring and opposite teeth. Immediate loading as suggested by commercials and some dental clinics can therefore only include smiling and soft food. Immediate and permanent loading with chewing forces is only possible using a bar system for the rigid connection of at least four implants at the time of the implant placement, but still with a significant increased risk of implant failure and therefore always requires strict patient selection. Hence, soft food is recommended for three months even in this setting. In order not to raise false hope in patients the term immediate loading is not supposed to be used in single tooth replacement.
The main reason for the limited indication of immediate single tooth replacement is primarily the lack of bone quantity in the extraction socket, which prohibits adequate bone drilling in the apical region to achieve primary stability requiring a healing period of a submerged implant without any functional load. Scientific literature reports on success rates of immediate implants similar to delayed implants. However, one has to keep in mind that cases of immediate implantation described in the literature are less than 2% of all implant cases, comprise highly selected patients with limited indications and can therefore not be compared to the standard treatment in the real world.
In view of the troublesome procedures necessary, the limited indications and the low number of patients treated successfully so far with hardly predictable results in the field of immediate dental implantology the questions arises, whether it makes sense at all to model the bone around the loose fitting rotationally symmetric implant by use of a number of invasive interventions, instead of adapting the implant to the underlying anatomy of the extraction socket.
Eventually the natural extraction socket represents the ideal anatomy and starting point for a root formed implant. This anatomic bone situation is ideal for the absorption of the load of a root analogue implant. Why change the anatomy by drilling and on the other hand augmentation of gaps between implant and bone?
On the other hand the fact, that the rotationally symmetric implants does not fit at all, leads to a remodeling of the regular and natural anatomy of the bone and leads a horizontal and vertical atrophy described also as remodeling. In many cases the atrophied bone especially in the presence of thin soft tissue looks not natural at all and grey implant shoulders become visible. These complications can occur within days after implantation or even after years in the context of old age involution of the alveolar bone regression. A correction of this failure requires again a number of invasive procedures with questionable outcome. Because of the fact that old age involution cannot be prevented, it is advisable not to use metallic implants, but rather implants whose color resembles that of the natural tooth. In such a case old age involution which leads to exposure of the implant shoulder does not pose a problem, since the outcome is comparable to a common exposure of the neck of the tooth.
The only logical consequences from the high number of inadequacies of presently available immediate implants is to develop and design an immediate dental implant which matches both in form and color the natural tooth fitting exactly into the tooth socket and in fact it is high time to do some research in this field because we hardly find any serious attempts in literature.
Respecting the anatomy of the soft and hard tissue by using individual anatomical formed Zirconia implants for immediate root replacement makes drilling, risk bearing augmentations and barrier membranes absolute unnecessary. This minimal invasive and very easy method enhances patient acceptance and maximizes functional and esthetic outcome. Already the surgical implantation equals bone loss, since the tooth socket has to be adapted to the rotationally symmetric implant regularly by drilling. In addition to the bone loss inherent to the system this procedure is technically demanding and causes strains to the patient.
It is high time to overcome conventional wisdom which suggests that only prefabricated, rotationally symmetric implants osseointegrate. Such a foundation which does not fit the extraction socket at all makes it difficult to impossible to achieve an esthetic emerging profile especially in the long term. The wide array of different available implant forms clearly indicates that osseointegration does not primarily depend on the form of the implant. Besides the surface it is important to prepare the implant site in an atraumatic way and to achieve a perfect bone to implant contact.
There is absolutely no logical reason at all not to use the already existing intact tooth socket as implant site and to adapt the implant to the tooth socket instead of the vice versa approach including drilling, bone trauma, bone loss and additional bone augmentations.
Root analogue titanium implants failed completely
All attempts in the long history of dental science to fix homologue, heterologue or allogenic root analogue implants into a fresh extraction socket failed due to the conical root form, rejection and lack of preciseness and were therefore not established. With the implementation of the modern CAD/CAM technology it became easily possible to manufacture an exact copy of the dental root or an extraction socket analogue to be used as dental implant.
This method has been employed by Kohal et al. in the 90s of the past century and this system by the name ReImplantt was thoroughly investigated in various studies (e.g. Clin Oral Implants Res, 1997). The initial success could not be confirmed in the long run. Eventually the failure rate under consideration of the conventional criteria reached 97% which precluded any further clinical use. Kohal et al. postulated that the main reason of the exceedingly high failure rate was, fracture of the thin cortical bone with consequent resorption of hard and soft tissue, resulting in implant loss and very poor esthetic out come.
Immediate individual Zirconia Implant
The immediate individualized Zirconia implant, which has stood the test of time in a clinical study over 3 years, constitutes an absolutely novel approach to solve the manifold problems immanent to the conventional system of immediate implants as there are mainly complicated drilling and augmentation procedures.
The indication for the use of immediate individualized Zirconia implants are root caries, vertical and horizontal root fracture, chronical apical parodontitis, and unsuccessful root canal treatment. Up to now patients are supposed to have intact periodontal ligaments. In our experience, chronical apical parodontitis does not constitute a contraindication not a bit, however, at the time point of tooth extraction all infected tissue has to be curetted. On the other hand patients with severe dehiscence of the crestal bone and with tooth extraction necessitating surgical intervention leading to contusion or bone loss were so far excluded from this treatment modality.
The target tooth is extracted gently by means of a periotome to avoid any damage to the extraction socket, which is to be used as implant site. Particular care has to be taken not to destroy the thin buccal cortical bone. The root of the extracted tooth or an impression of the extraction socket serves as basis for the production of the individualized immediate implant. Macro-retentions, strictly limited to the interdental space, are designed, the buccal and lingual face is slightly reduced and a crown stump is constructed for later connection to the crown in the laboratory. The prepared root is then laser scanned and the implant milled form a medical-grade Zirconia block, the surface roughened by sandblast and sintered for eight hours to achieve the desired mechanical properties. Thereafter the implant is cleaned in an ultrasonic bath containing 96% ethanol for 10 minutes, packaged and steam sterilized. Within 10 hours the customized root analogue implant is ready for use.