Regeneration of alveolar bone with membrane techniques has become an integral part of implant dentistry. The aim of the present study was to determine if laser-modified titanium membranes are of value in the regeneration of so-called critical size defects in the rat model compared with titanium membranes that were coated with growth factors. A total of 24 rats were included in the study. Critical size defects were created bilaterally and covered by titanium membranes coated with (1). polylactide, (2). polylactide and clindamycin, (3). polylactide and growth factors, (4). polylactide, clindamycin and growth factors and (5). uncoated but laser-modified titanium membranes. All 18 control defects were covered by titanium membranes without any substrate. Four weeks after treatment the animals were killed. Laser-modified titanium membranes (group 5) showed new bone formation in many areas. Nevertheless, complete bridging was found only in one specimen. In contrast, in groups 3 and 4, most defects showed almost complete bridging of the defects. In particular, clindamycin had no inhibitory effect on bone healing. Furthermore, after 28 days, there was no significant difference between the individual groups (including controls) with respect to the total amount of lamellar bone. Growth-factor-coated membranes can significantly accelerate the healing process of bony defects in the rat mandibular model. Nevertheless, it is not possible to accelerate bone healing with laser-irradiated membranes or to enhance the quality of bone within the time period examined.