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Dental Tribune Middle East & African Edition

20 Dental Tribune Middle East & Africa Edition | March-April 2015implant tribune Drill through the tooth technique for molar implant placement > Page 21 By Dr. André C Hattingh BChD, MChDcumlaude,SpecialistPeri- odontist&Dr.CostaNicolopoulos BDScumlaude,FFD(SA),Oral& MaxillofacialSurgeon T he immediate placement of a “conventional” (4-6 millimeter diameter) den- tal implant into a molar extrac- tion socket poses a number of difficulties. Most significantly is the size and shape of the multi- rooted molar socket. It is not suited for optimal placement of a typical dental implant and of- ten results in compromised im- plant positioning, poor primary stability or the inability to place an implant at all. This may result in the need for a waiting period of 3 to 6 months, to allow for healing of the socket and bone formation prior to attempting implant placement. This waiting period often ends in reduced bone volume (height and width), which is inadequate for implant placement and the resulting need for bone aug- mentation procedures, espe- cially in the posterior maxilla. This necessitates longer treat- ment times with increased cost and complexity. An alternative approach has been to place a 5-6 millimeter diameter implant into one socket of a multi-rooted extraction site, typically the pal- atal socket of a maxillary molar. Problems associated with the latter approach include adverse biomechanical forces resulting from the implant being off-cent- er and off-axis to the application of load. Poor emergence profile and difficult plaque control also result from the unavoidable buc- cal overhang of the restoration. The ability to place an implant immediately into a fresh molar extraction site embodies a ma- jor advantage in molar tooth replacement. This modality is however critically dependent on the preservation of the pe- rimeter bony walls of the socket at extraction. In the case of a multi-rooted molar tooth, it is recommended not to attempt a conventional extraction, but to plan for the individual removal of roots in order to avoid poten- tial fracture of the buccal plate. If the crown of the molar is cut off horizontally (Fig.1), prepara- tion of the osteotomy site can be initiated through the pulpal floor (Fig.2) and into the interradicu- lar bony septum (Fig.3). It is important to consider the periodontal biotype of the pa- tient when applying this proto- col. Medium to thick periodontal biotypes are the most suitable cases. Thin biotypes are contra- indicated for this treatment ap- proach and it is recommended that “traditional delayed proto- cols” are followed for thin bio- types. Preparation of a pilot hole through the pulpal floor (Fig.2) of a decoronised molar (Fig.1) should specifically be directed slightlytowardthelingualaspect (Fig.5) in the case of a mandibu- lar molar and slightly toward the mesial aspect (Fig.6) in the case of a maxillary molar. Maxillary molars often have more space available on their mesial aspects (between the first molar and the second premolar) than on their distal aspects (between the first and second molars – Fig.4). It is of the utmost importance that these initial preparation guidelines are followed in or- der to ensure that the final oste- otomy preparation is away from the buccal wall (in the case of a mandibular molar where the bucco-lingual dimensions are critical) and away from the me- sio-buccal root of the maxillary second molar (in the case of an upper first molar replacement). The aim is to initiate preparation in the following positions: • Mandibular first molar (Fig.5) • Maxillary first molar (fig.6) The roots can then be sectioned and carefully removed taking care NOT to remove any bone in the process (Fig.7a). It is es- sential to then inspect the socket walls and to ensure that all 4 walls are present and intact. If any of the required 4 walls are absent or significantly damaged, immediate implant placement becomes contra-indicated and a delayed protocol is then advised. Once the roots are removed, fur- ther preparation of the socket is carried out to create a suit- able tapered shape (Fig.12.) that could receive the implant. Incremental preparation is used (Fig.7b) before finalizing the site. Finalization of the placement site is achieved with a dedicated Max drill (Fig.8) specially devel- oped for hard bone. These drills match all the available implant lengths and diameters in the range of the Max implant. In softer bone the pre-placement preparation can be finalized with a dedicated Max tap (Fig.9). Lateral compaction of soft bone is enhanced by the use of this instrument, as is the accuracy of osteotomy site finalization in terms of position and angle. These taps again, match all the available implant lengths and diameters in the range of the Max implant. They can be hand driven using a surgical wrench as demonstrated in Fig. 10 & 11. The taps are specifically de- signed with a strengthened por- tion on the driving shaft, near the neck of the instrument. This contains a hexed collar, which slots into a sleeve, allowing connection to a surgical hand wrench. Potential instrument fracture and damage to surgical handpieces, are significantly re- duced by this innovation. A third finalization instrument can be used in situations where the interradicular bony anatomy Fig. 1. Mandibular molar decoron- ised at cervical level Fig. 4. More bone available on the mesial than on the distal of an upper first molar Fig. 7a. Careful removal of roots without any bone removal Fig. 7b. Incremental preparation with conventional drills Fig. 2. Pilot hole preparation through pulpal floor Fig. 5. Preparation started slightly toward the lingual in the case of a lower molar Fig.8. Dedicated Max drill Fig.10. Dedicated Max tap driven with surgical wrench Fig.11. Dedicated Max tap driven with surgical wrench Fig.12. Preparation of centrally located interradicular bone septum Fig.13. Osteotome in place to assess preparation before implant place- ment Fig.15. Osteotome design Fig.18. The 2x2 position rule Fig.14. Osteotome in place Fig.17. Max implant for molar extraction sockets Fig.16. Osteotome in molar socket used in finalization of preparation Fig.9. Dedicated Max taps Fig. 6. Preparation started slightly toward the mesial in the case of an upper molar Fig. 3. Drill through pulpal floor into interradidular bone septum Fig.19. Laser markings on fixture mount at platform level and at 3mm Fig.20. Healing abutment connec- tion and soft tissue adaptation with sutures Fig.21. Healing abutment connection and radiographic evaluation Fig.22. Restoration immediately after placement Fig.23. Follow up at 1 year

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