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ePaper created 2016-03-07, 22:38:59 | version 1.38.0
Volume 2 | Issue 1/2016 23 Journal of Oral Science & Rehabilitation Flaple ss so cke t pre se r vati o n pro ce du re Introduction The treatment of extraction sockets is a daily challenge in clinical practice. Several changes to the bone dimensions occur after tooth extrac- tion, since the alveolar bone is a tooth-depen- dent tissue.1 Bone modeling and remodeling are unavoidable during healing of an extraction socket.2–4 A number of studies have pointed out that most of the resorption occurred during the first three months, although dimensional changeshavebeenobserveduptooneyearafter atoothextraction.5–7 The changes to the alveolar ridge after tooth extraction showed the greatest amount of bone loss in the horizontal dimension and a concomi- tant loss ofvertical ridge height, which has been reportedtobemoreevidentatthebuccallevel.5,8,9 The morphological changes at the extraction sites resulted in narrow and short edentulous alveolarridges;moreover,thealveolarcrestmar- gin tended to shift lingually/palatally according to a specific pattern. Some clinical data has indi- cated that the alveolar crest tends to move two- thirdslingually/palatallyfromtheoriginalbuccal edge; thus, the amount of resorption at the mid- facial point doubled the bone loss at the distal andmesialpoints.8 A recent consensus report assessed that it is important to distinguish between the various procedures used to preserve the alveolar ridge.3 Ridge preservationtechniques include all proce- dures that preserve the ridge volume within the soft- and hard-tissue envelope existing at the time of extraction.3 A ridge preservation proce- dure is recommended in the following circum- stances:whenimplantplacementisnotpossible at the time oftooth extraction, when the patient is not available for immediate implant place- ment,when primarystabilityofthe implant can- not be guaranteed, and when treating adoles- centpatients.3 Theuseofvarioustechniquesand biomaterials has been proposed overtime; how- ever,nosignificantdifferenceshavebeenshown between the various biomaterials, although col- lagen alone has been proved to be unable to counteract tissue changes after tooth extraction.5,4,10–12 An ideal grafting biomaterial should be re- sorbable,inordertoallowreplacementwithnew bonewhilebalancingthespeedofresorptionand thevolumetricstability.Theuseofagraftingma- terial with a high resorption rate results in the complete disappearance ofthe biomaterial after a few months. This has been observed for cal- cium sulfate after three months and for a poly- lactide-polyglycolide acid sponge after six months.13 Nevertheless, high resorption of the biomaterial is not always desirable, especially in anatomical sites where vertical and horizontal volumetric shrinkage are expected. The use of collagenated cortico-cancellous porcine bone has shown positive results in socket preserva- tion procedures after three months.14, 15 In fact, histological and histomorphometric analyses gave positive results in terms of newly formed bone,absenceofinflammatorycellsandsignsof active resorption of the grafted particles,14 sug- gesting that collagenated cortico-cancellous porcine bone could be suitable for ridge preser- vationprocedures. A full-thickness flap elevation during tooth extraction mayhave accounted forslightlymore pronounced bone remodeling compared with a flapless extraction, owing to the interruption of the blood vessels.9, 16, 17 Soft-tissue primary clo- sure was originally considered necessary for proper incorporation of the graft.2, 9, 18, 19 The earlyexposureofthemembranetotheoralcavity was thought to jeopardize the effectiveness of tissue augmentation;16, 20 these findings pointed out the importance of achieving full closure and primary healing when the socket is grafted and coveredwithamembrane.2 Experimentalmodelshavereportedlesspro- nounced bone remodeling when a flapless ap- proach was used for socket preservation,21 but there is still no consensus on the effect ofthe el- evation of a full-thickness flap. However, one study found no significant difference between the flapless and flapped approach.22 A recent study observed the effects of a full-thickness flap elevation on the regenerative process of socket preservation procedures.14 The compari- son between the flapped and the flapless proce- dures showed no significant differences in the histological and histomorphometric analysis, in terms of newly formed bone, residual graft and marrow space rates, suggesting that the expo- sure of the collagen membrane did not jeopard- izetheregenerativeprocess.14 The aim ofthe current studywas to evaluate the clinical outcomes of a ridge preservation technique with a flapless approach in the poste- rior area of the jaw. Dimensional changes to the hard and soft tissue at fresh extraction sites treated with the use of cortico-cancellous porcine bone and a resorbable collagen mem- Volume 2 | Issue 1/201623