In vitro scanning electron microscopic comparison of inner surface of exposed and unexposed nonresorbable membranes

The purpose of this study was to analyze the attached tissues and the membrane surface condition according to barrier membrane exposure.

The selected patients underwent implant surgery with guided bone regeneration, then were surgically reentered to remove the membrane when the membrane was exposed early or when the second surgery of implant was done. The membranes used in the study included titanium mesh (Jeil Medical Co., Seoul, Korea), Frios titanium shield (Dentsply Friadent, Mannheim, Germany), and TR-Goretex membrane (W. L. Gore & Associates, CA, USA). Group 1 included 9 cases that had membranes that were exposed during an early period. Each membrane was removed in 3-6 weeks. Group 2 included 8 cases that had membranes that were not exposed and each membrane was removed in 12-24 weeks during the second surgery period of implants. Removed membrane samples were observed with scanning electron microscopy.

The membrane surface condition and the observed tissues were significantly different between the exposed membrane group and the unexposed membrane group (P < .05). In the majority of the cases of early exposed membranes, organic film and soft tissues were observed beneath the membrane. Bony debris was observed in only 1 sample from the exposed group. In the exposed group, the degree of membrane damage was more severe than in the unexposed group. The membrane surface condition and the observed tissues had no significant difference among the 3 kinds of membranes (P > .05).

The observed tissues and the membrane surface condition were affected by the membrane exposure. If the membrane is exposed, the soft tissue and organic film interfere with direct contact to the bone, and this affects the barrier membrane surface condition and bony tissues.