TissueCare News 05/2010

The bone ring technique: single-session vertical augmentation and implant placement with ANKYLOS ensures long-term stable tissue

EDITORIAL

Dear reader,

about six years ago, during treatment of a patient with a bone defect, I had the idea of using a ring-shaped, autogenous bone graft for the augmentation and of placing the implant in the same session. I have been developing this single-session bone ring technique step by step ever since and have applied it successfully in my dental practice. Now long-term success rates are available: My team has conducted more than 900 augmentations and implant placements with the ANKYLOS system in the practice clinic in Melsungen with a success rate of around 98 percent.

My colleague Dr. Orcan Yüksel, who is one of the first to use this technique, and I would like to present this unique protocol to you. The advantages will convince you too. In comparison with the classical bone-block augmentation, the bone ring technique saves the patient a second surgical procedure and reduces the total treatment time by to five months. The implant acts as a fixation element for the transplanted ring-shaped bone block. This makes it unnecessary to wait for the fixed bone block to heal before the complete prosthetic restoration. This newsletter describes the procedure step by step from bone harvesting to implant placement, discusses indications and prerequisites for application of the bone ring technique and explains why ANKYLOS with the tissue-preserving TissueCare Concept offers the ideal conditions for the procedure.

I would be pleased to welcome you to one of our practical courses with a live operation and hands-on practice. Once you have learned the bone ring technique step by step, seen its application and then tried it for yourself, you want to integrate it successfully in your daily practice.

Yours sincerely
Dr. Bernhard Giesenhagen

Vertical augmentation and implant placement in just one operation

How to conduct a successful restoration in only one session with the bone ring technique and repair a bone defect with a three-dimensional vertical augmentation and also with one implant was the topic of a lecture in Frankfurt on May 28, 2010, by the developer of the method, Dr. Bernhard Giesenhagen, and one of the earliest users of the technique, Dr. Orcan Yüksel.

It is well know that atrophied alveolar ridge regions and bone defects make implant placements difficult. Autologous bone is considered the gold standard for the therapy of vertical bone remodeling. Donor regions for autologous bone include the chin, palate, hips or the retromolar region. In general, these procedures require two surgical procedures and are tedious for patients. The protocol for transplantation of bone rings, developed by Dr. Bernhard Giesenhagen in 2004, enables the surgeon to remodel bone and also place implants in one session. This new "bone ring technique“ protocol covers the harvesting of the precisely fitted bone ring transplant from, for example, the chin or palate region, the three-dimensional vertical augmentation of the bone defect, and the implant placement (see below: "Bone ring technique – step by step").

Special advantages
"The advantages of this method are obvious," says the father of the bone ring technique, Dr. Bernhard Giesenhagen (Melsungen): "The protocol reduces the total treatment time by about five months compared to the classical bone block augmentation." It is not necessary to wait for the bone block to heal. The implant acts as a fixation element for the transplanted ring-shaped bone block. At the same time the implant with the bone block becomes osseointegrated into the recipient site. Giesenhagen: "In addition the technique simplifies basic augmentations for the practitioner and it is very user-friendly."

Even though the protocol is very simple and easy the surgical experience of the practitioner is essential for its success. "The key to success is correct treatment of the soft tissue," states Giesenhagen. His colleague Dr. Orcan Yüksel, who has been an enthusiastic user of the bone ring technique for about five years, adds: "It is essential for the surgeon to have some experience in periodontal surgery and has already carried out transplants." At the end of the surgical procedure the tension-free wound closure is absolutely essential. A major part of previous failures has been caused by suture dehiscence, notes both Giesenhagen and Yüksel. "Another advantage of this method," says Yüksel, "is that the transplant and the recipient site can be precisely fitted together with standardized round trephine drills (Helmut Zepf Medizintechnik GmbH)." This ensures that as many vital bone cells as possible come into contact with the cancellous part of the bone ring. Yüksel: "This establishes the best conditions for complete revascularization of the transplant."

ANKYLOS – the ideal implant 
The bone ring technique offers patients a virtually certain long-term success rate: a total of 98 percent is the success rate for the technique. This is based on the long-term success rate over a period of six years. The Melsungen clinic has carried out more than 900 augmentations with this protocol, all using the ANKYLOS implant system. Only nine implants and 21 bone rings were lost. Giesenhagen emphasizes that he works exclusively with the ANKYLOS implant system.

"ANKYLOS offers the ideal conditions for the success of the technique. The treatment protocol has made this clear." Giesenhagen and Yüksel are convinced of this and describe why this proven implant system with the tapered connection that has been clinically proven over more than 20 years fulfills all the requirements for the bone ring technique in one implant: "The progressive thread in the apical region requires only two to three revolutions into the local bone for sufficient primary stability." Yüksel: "This is exactly what we need, because in many cases there is no more than three millimeters of bone available. We also need a parallel-walled implant system, which in contrast to tulip-shaped tapered systems, enables the ring transplant to fit exactly around the implant. It is also important for the implant to have no thread in the neck region, otherwise the ring would rotate with the implant when it is finally tightened and spoil the fit." The bone ring is fixed with the membrane screw to prevent movement, which is already available in the ANKYLOS range, and the soft tissue is sutured without tension. Last but not least: the unique ANKYLOS TissueCare Concept provides a special keyed and friction-locked conical implant-abutment connection. It prevents micromovement between the implant and abutment and also microleaks, which can result in bacterial colonization and then inflammation and atrophy of the surrounding hard tissue and soft tissue. This is of course the last thing wanted after a successful transplant procedure. The bacteria-proof connection also allows subcrestal placement of the implant, which is important for use of a membrane screw for fixation. The system-immanent platform-switching, i.e. the offset of the joint gap inwards, and the microrough implant neck allow the bone to grow up to the implant shoulder. All this guarantees long-term and sustainable hard-tissue and soft-tissue stability. Yüksel: "But not every tapered implant system is suitable; it depends on the optimum length and the angle of the taper to achieve the desired stability and tightness. This procedure is a symbiosis of a unique augmentation technique and the ANKYLOS implant system. This is the key to success with the bone ring technique."

The interview

with Dr. Bernhard Giesenhagen and Dr. Orcan Yüksel

Dr. Giesenhagen, Dr. Yüksel, what sort of dentists are included in the target group for the bone ring technique?
Yüksel: We are initially addressing all dentists who are involved in implantology. The question is who will be successful. I believe that the user of the bone ring technique should, for example, have a knowledge of anatomy to know exactly what must be done during treatment. The user should be an expert in incision technique and should have learned how to manipulate soft tissue.
Giesenhagen: Practitioners should also know their bones and the various bone qualities. The same applies for soft tissues. This means that they should be expert in periodontal surgery. In my opinion these are the basic requirements for successful implant placement and also for successful augmentations.

Must the practitioner be an oral surgeon?
Giesenhagen and Yüksel: No, that is not absolutely necessary. But everyone who places implants should have a detailed knowledge of bone and soft tissue. Our target group is surgeons and dentists with experience in implantology.

What short of learning curve should users expect?
Yüksel:  If they meet the above basic requirements, I would initially recommend a theory course to understand the technique. This should be followed by a practical course with a live operation and hands-on practice over one and a half days.
Giesenhagen: A postgraduate course in implant dentistry was be desirable as a base, and I would also recommend a course in anatomy, including dissection of cadavers. This would not only refresh the practitioner's anatomical knowledge but also give an opportunity to practice the bone ring technique or sinus floor elevation on a human preparation (for more information in the Internet see www.bonering.de).
Yüksel: Practitioners should attend at least one of the practical courses before trying the bone ring technique for the first time. The courses discuss the success factors and risks of the bone ring technique that are the decisive factors for successful treatment in detail.

Do you offer supervision for new users of the bone ring technique?
Giesenhagen: Yes, colleagues can come to our practice with their patients and conduct the first operation with the bone ring technique under our supervision.

What indication would you particularly recommend for the first procedure?
Giesenhagen: The ideal first time would be the maxilla in the region of the first or second premolar. In my experience the bone defects in this region have not only a vertical but also a lateral limit.
Yüksel:  I would also consider the mandible with periodontally damaged front teeth, severe bone resorption and long cuspids good for a start. Extracting teeth, then placing two bone rings and two implants and then a four-element bridge – the risk of failure is low.

On what sort of case did you conduct the bone ring technique for the first time?
Giesenhagen:  I restored an edentulous mandible with large bone defects in the anterior region: naturally am ideal initial situation for a first case if the patient only receives four implants for an overdenture.
Yüksel:  I started with a demanding case. It was an anterior tooth with a 5-millimeter ring. But the procedure was very successful for me – with the assistance of Dr. Giesenhagen, who showed me how on the previous day …
Giesenhagen: An experienced surgeon could try challenging cases right from the start …

 What have been the reasons for failures in recent years?
Yüksel: Contamination of the bone block can be one reason. There are more than 300 different bacteria in the oral cavity. Another cause could be overheating of the bone or that the soft tissue was not closed adequately or that the bone ring was not stable.
Giesenhagen: Unfortunately, there is no such thing as a 100-percent success rate.

How long do you need for the procedure?
Giesenhagen and Yüksel: Now we need no more than half an hour; in hour experience bone harvesting from the palatal region is faster than taking bone from the chin region. Speed is not really the decisive factor, but the would region should only be open for a short time for hygienic reasons, and the wound flaps must be restored as quickly as possible.

What is your planning protocol with reference to imaging diagnostics?
Giesenhagen: In 99 percent of cases a two-dimensional imaging diagnosis is sufficient. In one percent of cases I take a DVT (Digital Volume Tomography) to be sure of tracing the course of the mandibular canal as securely as possible. Otherwise, I open the area, look at the defect and then I know exactly what I have to do. My eye is three-dimensional.
Yüksel: That is my opinion also. Our years of experience provide the required security. However, we a reworking on supporting the bone ring technique with 3D planning.

How many users are successfully applying the bone ring technique now?
Giesenhagen:  I don't know exactly, but I can make a guess. It could be 80 international users and 30 in Germany. Implantologists from Asia often attend our courses, because the very delicate bone structures in their patients cause them difficulties. However, the US market, for example, has not been addressed at all. We are just at the beginning of widespread use of this method.

Thank you for the interview.

The Bone Ring Technique – step by step

Twelve important steps lead to success, and to exciting esthetic results. The developer of the single-session bone ring technique, Dr. Bernhard Giesenhagen (Melsungen), described the procedure step by step.

"First, I measure the defect with a trephine drill while keeping about one millimeter distance from the neighboring tooth," explains Giesenhagen. The donor site can be selected from the chin region, the palate or the retromolar region.

Preparing donor site 
"The chin region has the right bone quality combined with sufficient volume to make it very suitable. I can harvest four or five rings from the chin region. The recommended procedure here is a T-incision to prevent damage to the mental nerve. I prepare the chin muscle and the periosteum to the chin margin. Here it is important to maintain a distance of three millimeters to the root apices and to the chin margin." Otherwise the procedure may result in healing deficits and a change in physiognomy. Now, however, Giesenhagen's preferred donor site is the palate: "It is faster, and there is no danger of postoperative paresthesia."

"I open the donor site and mark the bone ring with a standardized trephine drill, which I have developed in consultation with Helmut Zepf, with a hole approximately half a millimeter in depth." If the diameter for the ring-shaped transplant is six millimeters, the trephine drill with a one millimeter larger diameter should be selected for the donor site, in this case seven millimeters. "The two drills must fit inside each other like a telescope," says the lecturer. "This is the only way of achieving an accurate fit, the subsequently required ‘press fit’, of the transplant."

Preparing the implant site – removing the bone ring 
The implant site is prepared inside the marked ring with the instruments for the ANKYLOS implant system. "I use the instruments to penetrate the cortical bone, and the internal diameter of the ring is accurately matched with the implant diameter." This requires a careful procedure, because the cortical bone on the lingual side (anticortical bone) must not be perforated during the drilling: "The drill passes through the cancellous bone without difficulty, and when the anticortical bone is reached a resistance can be clearly felt."

 "Next I drill the final core hole with the trephine drill. This hole must be drilled with adequate water-cooling to prevent overheating the bone. The drilling should also be carried out intermittently and at a slow speed – maximum 200 rpm." The cancellous bone is removed from the cortical lingual bone with the "center ring punch“ and the bone ring is removed with the "ring lifter" (both instruments from Helmut Zepf). "This requires some patience. A quiet crack indicates that I can lift the bone block and I immediately place it in the covered container in the tray for secure storage.“ Giesenhagen noted the danger that the bone ring could "spring out". The assistant should therefore cover the area of the donor site lightly.

Customizing bone ring – placing implant 
After this step the defect at the recipient site is prepared for fitting the transplant with a trephine drill. The preparation depth is oriented to the bone margin of the neighboring teeth.

 Giesenhagen: "The implant diameter and length must of course be determined beforehand. I use the bone ring as a drill template." The press-fit ensures that the transplant is tightly seated. This is essential to ensure that the implant site can be prepared through the ring in accordance with the protocol.

The parallel-walled implant design of ANKYLOS, which has no thread in the neck region, guarantees that the transplant fits exactly around the implant, and the bone ring does not rotate with the implant as it is screwed in for the last three millimeters. The implant is inserted subcrestally through the bone ring. This enables the bone to grow up to the implant shoulder, giving it additional stability. The progressive thread to the apical region ensures the essential primary stability in the cancellous bone. If the primary stability is not sufficient, transplant and implant can be fixed with the membrane screw included with the ANKYLOS range. The remaining defect volume is filled with autologous bone chips and non-resorbable bone replacement material to hinder adaptation resorption. The recipient site is then covered with a resorbable collagen membrane, which is fixed with membrane tacks (FRIOS from DENTSPLY Friadent). 

Wound closure – summary 
A tension-free wound closure is an absolutely essential criterion for the success of the treatment protocol. "In some cases the flap ends should be de-epithelialized again to prevent subsequent dehiscence, because the flaps must remains closed. And the success rises and falls with the suture!" The minor disadvantage for the patient: "The patient can only eat soft food for four weeks." Six months later the implants are uncovered and the prosthetic restoration is delivered. Giesenhagen: "The bone ring technique saves patients a second surgical procedure and reduces the healing time by around five months – and results in safer, reproducible results. I recommend the ANKYLOS system unreservedly to ensure that the bone ring technique can be conducted successfully and with the lowest possible risk. My long-term success rates clearly demonstrate how stable the bone remains as a result of the ANKYLOS TissueCare Concept."