M a r c e l M .HL In d e B r a e k t , D .D .S. P h .D. J a a p C. M a l t h a , P h .D. A n n e M. K u ij p e r s-J a g t m a n , D .D .S ., P h .D. This article reports on the histologic findings from a larger study that was designed to investigate whether the attachment of scar tissue to underlying bone* which is normally found after palatal surgery, can be prevented by using biodegradable poly-(L-lactic) acid membranes. Von Langenbeck's procedure was simulated in 12-week-old beagle dogs without clefts. In one group normal wound healing was allowed. In two groups, membranes were inserted immedi ately after surgery or 3 weeks thereafter. Sham and control groups were also included. Histologic evaluation was carried out at regular intervals. Reports have been published on other aspects, such as clinical wound healing, contraction and maxillary arch development in beagle dogs following this treatment. After direct impiantation of membranes, wound healing was retarded. Disintegration of the membranes started soon after implantation and remaining particles were surrounded by a fibroblastic sheath and a fibrous capsule. At sites where mem brane particles persisted, attachment of the scar tissue to the underlying bone by Sharpey's fibers was prevented.