Comparison of bioabsorbable and bioinert membranes for guided bone regeneration around non‐submerged implants. An experimental study in the mongrel dog.

Abstract

The aim of this clinical investigation was to evaluate the effect of guided bone regeneration around non-submerged implants using different barrier membranes. Five adult mongrel dogs were used in this investigation. After having all premolars extracted and implant osteotomies performed in the regions of the former premolars, buccal bone defects were created. Subsequently, 3 implants were placed and the defects treated with 1 of the following 3 modalities: a) guided bone regeneration using an expanded polytetrafluoroethylene membrane, b) guided bone regeneration using a bioabsorbable membrane made from a synthetic copolymer of glycolide and lactide and c) no membrane application. Following implant and membrane placement, the mucoperiosteal flaps were repositioned and tightly sutured around the neck of the implants allowing for a non-submerged healing. After a healing period of 6 months, the animals were sacrificed and the specimens processed for histologic evaluation. The clinical pre-treatment defects between the different treatment groups were not statistically different (bioinert membrane group: 4.9 mm; control group: 4.8 mm; bioabsorbable membrane group: 4.5 mm). The remaining histological defects after 6 months of healing amounted to approximately 2.5 mm in the bioinert membrane group, 5.7 mm in the control group and 6.0 mm in the bioabsorbable membrane group. A significant difference was observed between the bioinert membrane group and the other 2 groups. The mineralized bone-to-implant contact in the bioinert membrane group was 51.5%, in the control group 46.3% and in the bioabsorbable membrane group 37.5%. The values between the bioinert membrane group and the bioabsorbable membrane group were statistically different. The results of this study indicate that bone regeneration with bioinert e-PTFE membranes around non-submerged implants is possible. The utilized absorbable polyglycolic/polylactid membrane did not show any bone regenerative effect and the results did not differ from the control group without membrane application.

Bone regeneration in dehiscence‐type defects at chemically modified (SLActive®) and conventional SLA titanium implants: a pilot study in dogs

“…Accordingly, the lack of new bone formation in the respective dehiscence-type defects at SLA implants might be explained by a partial or even full collapse of the blood clot within the first 2 weeks of healing, allowing the ingrowth of a poorly vascularized connective tissue inside the wound area. Similar results were reported by Kohal et al (1999), as non-submerged SLA implants also exhibited an increased DL from 4.8 AE 0.8 mm at baseline to 5.7 AE 1.1 mm after 6 months. However, previous histological observations in dogs have demonstrated that the blood clot adjacent to modSLA surfaces was generally substituted by a well-organized collagen-rich connective tissue at day 4.…”

“…In this context, it must be emphasized that the surgical creation of standardized buccal dehiscence-type defects in dogs is a commonly used procedure to evaluate bone regeneration adjacent to titanium implants (Becker et al 1990, Zablotsky et al 1991, Stentz et al 1997, Cho et al 1998, Hockers et al 1999, Kohal et al 1999, Casati et al 2002, Oh et al 2003). Within its limits, it was observed that modSLA implants exhibited a complete defect fill at 12 weeks following implant placement, while wound healing at SLA implants was merely characterized by the formation of a dense connective tissue at 2 and 12 weeks, without any increases in mean NBH, PLF, BIC-D or BF values.…”

Augmentation of Peri-implant Bone Defects with Different Bone Grafts and Guided Bone Regeneration:

“…The membrane technique in conjunction with the placement of dental implants has gained approving outcomes in clinical and experimental studies [15][16][17] . In the present study, both quantity and quality of regenerated bone in specimens without membrane's protection were superior to that of the specimens covered by titanium membrane.…”

Bioresorbable Collagen Membranes for Guided Bone Regeneration

“…Animal experiments (Gotfredsen et al 1993;Kohal et al 1999a) and clinical studies (Gher et al 1994;Simion et al1994;Hämmerle et al 1998) have shown that premature membrane exposure and wound dehiscence impair the amount of bone regeneration. Figure 4 presents the exposure and removal of an infected e-PTFE membrane.…”