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Implant Tribune Italian Edition

23Congresso Nazionale SICOI • Milano RELATORI Congresso Nazionale SICOI Hom Lay Wang Socket preservation: an important technique to avoid ridge resorption Why performing socket augmentation? Following loss of teeth, imminent bone resorption occurs where 50% of bone volume can be lost, of which two thirds arises within the first 3 months1 . This alveolar bone resorption is irreversible and cumulative2 , and occurs preferentially on the buccal plate3 . As a result, implant placement in an ideal esthetic and functional position becomes a challenge. A wealth of evidence in the literature demonstrates that ridge augmentation can create an environment favorable for maximizing bone growth, ultimately allowing for implant placement, and avoiding the need for future bone augmentation4 . When to perform socket augmentation and when to proceed with immediate implant placement? Following extraction of teeth, the decision is made to either proceed with immediate implant placement or ridge augmentation and delayed implant place- ment. Figure lists the decision tree for making this important selection of proper treatment. Immediate implant placement can be performed when implant primary stability can be achieved predictably, and the patient presents with a thick tissue biotype with a relatively thick buccal plate (i.e. ≥1-2mm)5-8 . Areas with minimal esthetic concerns are preferable. When the decision is to first augment the ridge and delay implant placement, selection of various bone grafting materials is dependent upon the anatomy of the extraction socket. When the extraction has been performed atraumatically and the residual bone walls are thick (i.e. ≥2mm) and intact, ridge augmentation is not necessary. Addition of bone grafts requires additional healing time. The extraction itself is sufficient to initiate the RAP, which enhances the healing potential9 . Moreo- ver, in these cases where ridge augmentation is not necessary, the extraction socket is better left exposed rather than achieving primary closure because increased bone resorption is observed in sockets covered by connective tissue10 . On the other hand, when socket walls are well contained but rather thin (i.e. <2mm), the mineralized bone plug technique can be used11 . In this technique, a mineralized bone allograft with an absorbable collagen dressing are placed. In a beagle dog study, GBR procedure performed on the buccal wall in addition to placing graft material inside the extraction socket failed to maintain ridge width because of additional trauma that may compromise healing12 . Hence, additional GBR to increase bucco-lingual width is not required. In cases where socket walls are not contained such that the buccal plate is absent, the technique depends on tissue thickness. In a patient with thick tissue biotype (i.e. ≥1.5mm)13,14 , GBR is performed using a bone graft with non resorbable membrane such as non-expanded PTFE or ePTFE. Primary wound coverage is critical to ensure healing. In a rather thin biotype (i.e. <1.5mm), bone graft in conjunction with a bioabsorbable membrane is used. Once again, primary coverage is critical. Reference 1. Schropp L, Wenzel A, Kostopoulos L, Karring T. Bone healing and soft tis- sue contour changes following single-tooth extraction: a clinical and radi- ographic 12-month prospective study. Int J Periodontics Restorative Dent 2003;23(4):313-323. 2. Atwood D. Postextraction changes in the adult mandible as illustrated by microradiographs of midsagittal sections and serial cephalometric roent- genograms. J Prosthet Dent 1963;13810-824. 3. Araujo MG, Lindhe J. Ridge alterations following tooth extraction with and without flap elevation: an experimental study in the dog. Clin Oral Implants Res 2009;20(6):545-549. 4. Wang HL, Kiyonobu K, Neiva RF. Socket augmentation: rationale and tech- nique. Implant Dent 2004;13(4):286-296. 5. Juodzbalys G, Wang HL. Soft and hard tissue assessment of immediate implant placement: a case series. Clin Oral Implants Res 2007;18(2):237- 243. 6. Kazor CE, Al-Shammari K, Sarment DP, Misch CE, Wang HL. Implant plastic surgery: a review and rationale. J Oral Implantol 2004;30(4):240-254. 7. Spray JR, Black CG, Morris HF, Ochi S. The influence of bone thickness on facial marginal bone response: stage 1 placement through stage 2 uncov- ering. Ann Periodontol 2000;5(1):119-128. 8. Evans CD, Chen ST. Esthetic outcomes of immediate implant placements. Clin Oral Implants Res 2008;19(1):73-80. 9. Misch CE, Silc JT. Socket grafting and alveolar ridge preservation. Dent Today 2008;27(10):146, 148, 150 passim. 10. Camargo PM, Lekovic V, Carnio J, Kenney EB. Alveolar bone preservation following tooth extraction: a perspective of clinical trials utilizing osseous grafting and guided bone regeneration. Oral Maxillofac Surg Clin North Am 2004;16(1):9-18. 11. Wang HL, Tsao YP. Histologic evaluation of socket augmentation with mineralized human allograft. Int J Periodontics Restorative Dent 2008;28(3):231-237. 12. Fickl S, Zuhr O, Wachtel H, Kebschull M, Hurzeler MB. Hard tissue altera- tions after socket preservation with additional buccal overbuilding: a study in the beagle dog. J Clin Periodontol 2009;36(10):898-904. 13. Goaslind GD, Robertson PB, Mahan CJ, Morrison WW, Olson JV. Thickness of facial gingiva. J Periodontol 1977;48(12):768-771. 14. Bashutski JD, Wang HL. Common implant esthetic complications. Implant Dent 2007;16(4):340-348. << segue Se questa diagnosi viene fatta quando le lesioni sono troppo estese per essere trattate, purtroppo il dente deve essere estratto. E a questo punto cosa si può fare? Nel caso in cui non vi sia scelta e vada rimosso l’elemento dentario, la tecnica migliore rimane il posiziona- mento di un impianto osteointegrato. Tuttavia se decidessimo per la ter- apia implantare, andrà considerato un trattamento di ricostruzione ossea, per recuperare il tessuto di supporto perso per la malattia parodontale. A questo punto il paziente deve sapere che alcuni dei fattori che gli hanno fatto perdere il dente come fumo di sigarette e suscettibilità alla Malattia Parodontale, saranno fattori di rischio anche per la stabilità dell’osso vicino agli impianti. Questi impianti verranno poi finalizzati con una corona protesi- ca. Sappiamo che la vita media di una corona protesica è di circa dieci anni, bisogna mettere in conto che ques- ta corona (che sia su denti naturali o impianti non importa) circa ogni die- ci anni dovrà essere rifatta. Fatti due conti, biologici ed economici, risulta evidente il grandissimo valore di un dente naturale, e compito dell’odontoi- atra deve essere quello di preservare il più possibile la dentatura naturale dei propri pazienti, diagnosticando e curando in tempo le malattie.