Influence of synthetic polyethylene glycol hydrogels on new bone formation during mandibular augmentation procedures in Goettingen minipigs

Polyethylene glycol hydrogels (PEG) have been used as slow release carrier for osteoinductive growth factors in order to achieve a retarded delivery. However, there have been concerns about negative effects on bone regeneration. This study aims to test whether PEG hydrogels themselves affect new bone formation (NBF), when used as a carrier during mandibular augmentation procedures. In a randomized split-mouth design, bilateral mandibular bone defects were surgically created in 12 Goettingen minipigs, and subsequently augmented, using PEG hydrogel on one side of the mandible. The contralateral sides, without PEG, served as controls. After 4 and 12 weeks, bone formation was evaluated in six animals each. A comparison of the data, using a three-way analysis of variance (ANOVA), revealed a significant effect of the healing time and the region of the graft on the distribution and enhancement of NBF (P < .0001, respectively). Although a 0.3% (95%-CI [-5.5; 4.8]) lower volume density of newly formed bone could be observed over all PEG hydrogel sections, in contrast to the contralateral controls, the analysis revealed no clinically significant effects of the PEG hydrogel treatment on the total level (P = 0.90), and the distribution of NBF (P = 0.54). In conclusion, PEG hydrogels do not affect NBF when used as a carrier for osteoinductive growth factors during mandibular augmentation procedures.