“…wound healing potential, immune system, oral hygiene, defect morphology, smoking habits) (Tonetti et al 1995, Kornman & Robertson 2000, Cortellini & Tonetti 2000, there is strong evidence that membrane specific problems (e.g. Although the strict plaque control regimens of previous controlled clinical studies appeared to prevent a harmful effect of postoperative membrane exposures on the attachment gain (Becker et al 1996, Christgau et al 1997b, membrane exposures dramatically increase the risk for bacterial contamination and penetration of the exposed membrane parts (Grevstad & Leknes 1993, Nowzari et al 1995, Nowzari et al 1996, Chen et al 1997, MacDonald et al 1998). Bacterial contamination of the membranes can have a detrimental effect on the periodontal regeneration (Nowzari et al 1995, Slots et al 1999.…”