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Dental Tribune United Kingdom Edition

Implant Tribune pages 11-16 Using the two-piece implant shuttle Flapless MIMI® Implementation Implant Tribune pages 17-18 By Theirry Lachkar Customised implant abutment Implant Tribune pages 19-20 What are the treatment options? Perio-implantitis Implant Tribune Fig. 1: Implant on the right: Physiologically speaking, bone loss has been considered as inevitable, and some traditional implants are frequently associated with bone loss. page 12DTà Flapless MIMI® implantation using the two-piece implant shuttle preventing physiological bone loss Armin Nedjay discusses Flapless implants A ccording to valid scien- tific criteria for a suc- cessful implant treat- ment, bone loss after one-year loading is considered as inevita- ble1 . Thus, the implantation is de- fined as successful when crestal bone loss does not exceed 2mm after one-year loading time and 0.2mm annually thereafter. With more than 22,000 suc- cessful implantations with im- mediately restored and loaded implant systems, the author de- scribes solutions that have been successful in preventing physi- ological bone loss. With respect to Tarnow’s findings concerning bone loss2-4 , the author has sug- gested that the periosteum pre- serving MIMI® procedure with implants that have an integrated Platform-Switching design and that can achieve primary stability has a proper potential to prevent physiological bone loss. Since bone loss can be evidenced if an- implant is uncovered, it is also recommended to avoid implant exposure. Implant Design & Physiologi- cal Bone Loss Most traditional implant systems have a conventional platform- matched implant-abutment con- nection. External and internal connections can have an impact on the hard and soft tissue in- terface. Long-term studies have shown that the peri-implant bone level is established apically from this platform-matched implant- abutment connection (Bullon 1999). If the implant, surround- ed by bone, heals with its cap screw in bone until its exposure and if the cap screw is removed by means of ostectomy and re- placed with a healing cap, a bone remodeling process starts after exposure. This can lead to a peri- implant bone defect (Fig. 1, im- plant on the right). Micro-gap The micro-gap is located be- tween the implant body and abut- ment. It has been considered as a disadvantage of two-piece im- plants. If the micro-gap is too big, as is the case with many conven- tional two-piece implant systems and due to loading of the implant- abutment connection, there is a high risk of bacterial contamina- tion of the micro-gap and implant body. This can lead to bone loss. X-ray images of some two- piece implant systems (eg ITI), which are connected to the oral cavity, have shown that the biological vertical distance be- tween the micro-gap and the implant-bone contact area is 2mm, regardless of how deeply the implant is inserted in bone (Hermann 1997, 2000 and 2001). Tarnow2-4 has demonstrated in his studies 2000 and 2003 that the micro-gap expands horizontally by about 1.4mm, which is similar to the effect in case of a periodon- tal defect. Tarnow recommends that the minimum distance be- tween two implants should be 3mm to protect bone and inter- implant papillae. Platform Switching Implants with a Platform-Switch- ing concept have a proper poten- tial to prevent bone loss15,16 . The diameter of the healing abutment is narrower than the diameter of the implant platform/shoulder. In this way, the implant-abut- ment connection is not platform- matched. Dental implant systems such as the Champions (R)Evo- lution® (Fig. 17 & 18), Ankylos® and Astra Tech® have an inte- grated Platform-Switching design and an internal cone that is long enough and that has an optimal angle. In addition, the geometry of the implant-abutment connec- tion is the same for all implant diameters, so there is a pros- thetic line for all implant diam- eters. With the Platform Switch- ing function, the central position of the micro-gap is moved to the implant axis. Through the sepa- ration of the micro-gap, which might risk being contaminated with bacteria, from the peri-im- plant bone tissue in the implant shoulder area, the biological width is shifted away from bone. As a rule, an exposure of the Champions (R)Evolution® im- plant and a reopening/ injury of the sensitive biological width are not necessary. In this way, biolog- ical bone loss can be avoided, and the issue according to Tarnow re- mains to be discussed, also with respect to one-piece implants. Conclusion Conventional implantation meth- ods have been increasingly ques- tioned13,14 . MIMI® is the abbre- viation for the Minimally Invasive Method of Dental Implantation. One-piece implants and also two- piece implant systems will be ide- al for MIMI® if they can remain bacteria-resistant even if they are loaded with strong forces. Sulcus 0,2 - 0,5 mm Epithelial attachment about 1 mm Connective tissue attachment about 1 mm Dento- gingival complex Biological width Fig. 2: The epithelial attachment in natural teeth and the one in osseous implants have many features in common, but there are also differences between them. The connective tissue fibers adjacent to the implant are in parallel with the longitudinal axis of the implant, which is different from the biological structures around natural teeth5-8. There are no nerve and vessel structures adjacent to the implant surface; the tissue is similar to scar-like tissue and differs from periodontal tissue, which is connected to the tooth and alveolar bone. Fig 3: Soft tissue consists of the sulcus, the gingival epithelium, and the connective tissue attachment. Their vertical height of 3 mm is called the biological width. A biological cuff-like barrier protects healthy implant surfaces/sites from apical migration of bac- teria. Hard and soft tissue, mineralized connective tissue (alveolar bone), soft connec- tive tissue and junctional epithelium serve as a protective barrier. Bacterial migration into the periodontal and periimplant soft tissue in the sulcus area causes an apical migration and destruction of soft and hard tissue, which can lead to an attachment loss9-11. Poor dental hygiene or the iatrogenic detachment of the periosteum with a flap reflection and/or an implant exposure can cause injury to soft tissue, which can lead to periimplantitis. Fig 1 Fig 2 Fig 3