A REVIEW

USC International Periodontal Implant Symposium

“THE AGE OF SPEED”

January 28-30, 2010

I attended the 35^th Annual USC Periodontal and Implant Symposium this last weekend. I found it to be very interesting and informative. Its objective was to evaluate the materials and protocols that have been designed to increase the speed of therapy. While some of these materials and protocols have been well documented, others are not supported by scientific data. Examples of some of the protocols developed include immediate placement of implants into extraction sites, immediate or early loading of implants and accelerated osteogenic orthodontics, computer-guided implant placement and microsurgery, minimally invasive surgery for implant site development and placement to reduce healing time. We were all cautioned that our ultimate objective in predictable therapeutic outcomes rather than the speed with which therapy is developed. I found that my general experience and instincts were generally reinforced as well as being introduced to new ideas

The keynote speaker Lars Sennerby reviewed the controversy of immediate (<72hrs) vs. early (6-8 wks) vs. conventional delayed (6mos) loading of implants after placement. His general conclusion was that immediate loading could be successful in fully edentulous cases in selected patients, with dense bone, using rough surface implants, where good primary stability can be achieved, by experienced clinicians. Cross arch stabilization is very important which may not be present in partially edentulous cases.

Dr. Maurizio Tonetti spoke about acceleration of periodontal regeneration procedures and cautioned that speed is not necessarily an advantage. He emphasized the importance of limiting tissue trauma and close tissue adaptation to accelerate healing through the use of microsurgical techniques. He introduced his Modified Minimally Invasive Surgical Technique (Mod MIST), which was very interesting. He stated that research does not support the concept that any material is superior to others in terms of speeding healing. Surgical technique is the most important. I have also found that to be true in my practice over the years, which is why I have emphasized microsurgical techniques in my practice. The most valuable part of his presentation was his review of the comparison of Guided Tissue Regeneration (GTR -Traditional Procedure), Enamel Matrix Derivative (EMD - a material), and Enamel Matrix Derivative/Minimally Invasive Surgery (EMD+MIST - a Procedure) in terms of patient comfort and regeneration results.

From these studies Dr. Tonetti concluded that the regenerative materials are not as important as the surgical technique as illustrated by the attachment gain and decreased morbidity shown.  He stated that, over the last 15 years, treatment, surgical technique development on flap design, execution and pre- and post-operative care (microsurgical techniques) has been the major contributing force to treatment outcomes. That is what I have experienced since I started exclusively using microsurgical techniques in about 1996.

Drs. Seong-Hun Kim and Kevin Murphy spoke about the concept of Accelerated Osteogenic Orthodontics and Periodontal Accelerated Osteogenic Orthodontics, which used the concept of surgically creating a wound on the cortical plate and bone ostectomies around teeth and then grafting before starting orthodontic movement, which then allows faster and more aggressive tooth movement than traditional orthodontic therapy. Examples were shown in which the time of treatment was decreased from an average of 2 years to 6-12 mos. In fairly advanced and complex cases with less complications! I have placed bone grafts on pre-orthodontic patients to improve the ridge width horizontally to decrease the chances of bony dehiscences successfully, but have not performed the alveolar wounding technique. This is a very promising treatment concept, which is still in its infancy in terms of the understanding of why and how it works. I think this concept that merits close monitoring.

Dr. Ziv Mazor and Dr Hong Chan Lee discussed various sinus grafting techniques. Again, the consensus was that the type of grafting materials does not matter as much as the importance of using a barrier, if a lateral window is performed and minimally invasive surgical techniques are used in sinus lifts. The advantage of piezosurgery techniques were stressed and the use of PRF (platelet rich fibrin). Dr. Lee introduced the alveolar approach for sinus grafting performed at the time of implant placement.  Their conclusions were similar to my experience in the use of minimally invasive techniques, use of piezosurgery, and growth enhancers such as PRP and PRF.  I have also found that the alveolar approach (I refer to it as a localized sinus lift in my surgical reports), when indicated, allows for faster completion of implant treatment with less patient discomfort. I first performed the alveolar approach to sinus lifts about 15 years ago and have found it to be very successful over the years in single implant cases with adequate bone for stability. Dr. Lee has expanded the concept using it multiple implant placements.

Dr. Uematsu reviewed the controversy of immediate implant placement (<3days) in extraction sockets, delayed placement (6-8 wks), and late placement (>6mos) in the esthetic zone in particular. His conclusion after reviewing many studies was that though immediate placement had the advantage of decreased treatment time, the unpredictability of the healing response exhibited experimentally in terms of gingival recession and bone support was not worth it. The delayed protocol showed good and predictable esthetic, as well as bone regeneration, results. Late placement (> 6 moss) resulted in more vertical bone loss but exhibited good esthetic predictability. The esthetic outcome is similar to delayed placement (6-8wks). His preference overall was delayed placement after tooth extraction with guided bone regeneration. That has been my experience and general approach so I was glad to have that confirmation of my approach clinically.

Dr. Igarashi reviewed his experiences with full arch implant restorations with immediate loading. He stressed the importance of cross arch stabilization and maximizing the anterior-posterior spread of implants. His guidelines were that the distal extension of a cantilever full arch splint be less than 15mm, Implants should be at least 3.5 x 10 mm in favorable bone with at least a torque value at placement of 35ncm.

Dr. Romanos reviewed the histological bone response to immediate and early loading vs. delayed loading suggesting loading during the early phase of bone remodeling improves bone density. He suggested placing implants 4 mos. after augmentation and loading no earlier than 6 wks after placement. He cautioned that this is not recommended in the esthetic zone, however due to esthetic risks and the importance of good initial implant stability at placement.

Dr. Lyndon Cooper reviewed the parameters required for immediate loading of implants. He also stressed the importance of primary implant stability, using rough surface, threaded, and tapered implants.  He also stressed that a minimum of 4-5 mm of bone is required apical to the socket and placement should be 3mm apical to the gingival crest and 2mm lingual to the ideal zenith of the tooth. He also cautioned not to place immediate implants if there is a buccal plate dehiscence citing studies showing significant recession in those types of situations. He emphasized, “If in doubt, graft and wait 6 mos. for implant placement."

Dr. Gunder reviewed the limitations of papilla regeneration and maintenance. He emphasized the importance of bone support in long term gingival height maintenance stating that the bone dictated gingival levels. He feels the maximum gain of soft tissue augmentation that can be expected is in the 3.5-4.5mm range, greater depth will eventually recede. Gingival grafting success can’t be claimed for at least 3 years long since initial success may begin to recede over time. He also stated that autogenous bone was not the best graft material for GBR procedures citing studies showing to its tendency for loss (50%) later on.

Dr. Marchak reviewed his experience with placing full arch zirconium-porcelain fixed hybrid dentures on implants. He claims good success with milled frameworks but his major problem has been porcelain fracture (3-5%). He suggests bringing the zirconium close to the contact surface or even replacing the occlusal surface in areas of high stress.

Dr. Rojao-Vizcaya reviewed a complex case of utilizing computer modeling to plan and carry out a treatment plan. He was able to maximize the esthetic and functional restoration in relation to implant placement with computer modeling.  He was able to anticipate and avoid potential problems prior to implant placement. In addition he was able to plan and construct temporary restorations prior to implant placement. This was a very impressive treatment of a complex case which showed the importance of the use of 3-D planning implant placement and the use of surgical guides in implant placement.  He confirmed my belief in the value of 3-D computer modeling techniques and utilizing guided implant placement. I have been using this technique on virtually all implant cases since about 1993.

Dr. Moy reviewed the use of BMPr-2 in bone augmentation cases and cautioned that rushing treatments are not necessarily the best for outcomes and our patients. There are certain basic biologic principals that should be respected. Pushing the envelope may result in unnecessary risks and can lead to problems. He reviewed situations where he was able to “save” previously failed augmentation cases. In association with this there was a “live” demonstration of a ridge augmentation of a severely atrophic mandibular defect by Dr. Jovanovic which was very interesting.

Dr.’s Yang Chai and Songtao Shi reviewed basic biologic research being done on stem cell research in relation to bone tooth growth and maturation and the role different growth factors such as BMP, TGIF, EMD, that are available to us, have in bone and tooth dynamics. They also gave us a brief view of potential technologies that may be available in the future.

Overall the symposium was very valuable and was a good review of the current “state of the art” in periodontics and implant dentistry. It confirmed many of the approaches I have been taking and I picked up some “gems” to fine tune my treatment techniques and approaches. I also got a glimpse promising future possibilities in treatment.

In summary, there seems to be agreement that the best approach is not necessarily the fastest approach. Biologic principals and predictable outcomes are more important than shorter treatment times which may be more risky. In implant placement initial implant stability (20-35ncm) must be established before considering anything else. Controlling stresses on implants during the healing phase is also critical to success. Implant placement in the esthetic zone, in particular, ideally should be done with 3-D evaluation (CT scans) and surgical guides. The general rule of implant placement was mentioned several times, “3mm apical to the gingival margin, 2mm lingual to the tooth zenith.” The best results seem to be with delayed implant placement (4-6 wks), particularly in augmented sites (4 mos.) and delayed loading (4-6 wks). In surgery, microsurgery and minimally invasive treatment procedures were superior to traditional procedures in terms of outcomes as well as patient morbidity.