It is well known that a tooth socket will undergo significant resorption and remodeling following tooth extraction. Pietrokovsky and Massler documented alveolar bone dimension changes subsequent to tooth extraction forty-five years ago. Schropp et al. evaluated tissue changes on models following premolar and molar extractions and concluded that 50% of the ridge width was lost within one year following extraction. Two thirds of this resorption happened during the first 3 months.
In addition to alveolar ridge resorption in a horizontal dimension (decrease in width), changes in the vertical dimension of the ridge have been documented following tooth extraction in a canine model (Araújo & Lindhe 2005). The healing pattern of the extraction socket observed in the preclinical setting was further confirmed in human investigations (Iasella et al. 2003, Barone et al. 2008, Oghli et al. 2010). A systematic review (Van der Weijden et al. 2009) concluded that greater loss of ridge width is to be expected following extraction compared to loss of ridge height. Clinical mean reductions of 3.87mm and 1.87mm in ridge width and height, respectively, were reported. Radiographically, the mean reduction amounted 1.21mm and 1.53mm for ridge width and height, respectively. These results were confirmed by another systematic review (Tan et al. 2012).
If the extracted tooth is to be replaced, the unfavorable dimensional changes resulting from this healing process may necessitate advanced and technique sensitive guided bone regeneration (GBR) procedures prior to dental implant placement. In order to avoid GBR and limit these dimensional changes, grafting of the extraction socket with or without membrane coverage, also called ridge preservation procedure, have been advocated (Araújo & Lindhe 2009, Iasella et al. 2003, Darby et al. 2009, Vignoletti et al. 2012). In order to perform ridge preservation, typically, a graft material and some sort of a barrier (e.g. non-resorbable and resorbable membranes or collagen wound dressing) are used. A large variety of materials are available on the market for the purpose of ridge preservation. No material gold standard has yet been identified to date, which would ensure the best dimensional stability of the alveolar ridge (Darby et a. 2009, Vignoletti et al. 2012).
Current materials used as part of standard care in clinical practice include freeze dried bone allograft (FDBA) as a grafting material and a dense polytetrafluroethylene (dPTFE) non-resorbable membrane or a collagen wound dressing (Collaplug®, Zimmer Dental, Carlsbad, CA) to protect the extraction grafted site. It is currently now known how the use of a collagen wound dressing would compare to a non-resorbable membrane (which has been documented) and if any would lead to any substantial clinical advantages.
Therefore, the proposed research project will answer the following question:
What are the dimensional changes of the hard and soft tissues encountered following molar extractions with ridge preservation using FDBA and a collagen wound dressing?