Bone augmentation at peri‐implant dehiscence defects comparing a synthetic polyethylene glycol hydrogel matrix vs. standard guided bone regeneration techniques

Objectives The aim of the study was to test whether or not the use of a polyethylene glycol (PEG) hydrogel with or without the addition of an arginylglycylaspartic acid (RGD) sequence applied as a matrix in combination with hydroxyapatite/tricalciumphosphate (HA/TCP) results in similar peri‐implant bone regeneration as traditional guided bone regeneration procedures. Material and methods In 12 beagle dogs, implant placement and peri‐implant bone regeneration were performed 2 months after tooth extraction in the maxilla. Two standardized box‐shaped defects were bilaterally created, and dental implants were placed in the center of the defects with a dehiscence of 4 mm. Four treatment modalities were randomly applied: i)HA / TCP mixed with a synthetic PEG hydrogel, ii)HA / TCP mixed with a synthetic PEG hydrogel supplemented with an RGD sequence, iii)HA / TCP covered with a native collagen membrane ( CM ), iv)and no bone augmentation (empty). After a healing period of 8 or 16 weeks, micro‐ CT and histological analyses were performed. Results Histomorphometric analysis revealed a greater relative augmented area for groups with bone augmentation (43.3%–53.9% at 8 weeks, 31.2%–42.8% at 16 weeks) compared to empty controls (22.9% at 8 weeks, 1.1% at 16 weeks). The median amount of newly formed bone was greatest in group CM at both time‐points. Regarding the first bone‐to‐implant contact, CM was statistically significantly superior to all other groups at 8 weeks. Conclusions Bone can partially be regenerated at peri‐implant buccal dehiscence defects using traditional guided bone regeneration techniques. The use of a PEG hydrogel applied as a matrix mixed with a synthetic bone substitute material might lack a sufficient stability over time for this kind of defect.