Tissue Eng Part B Rev. 2018 Feb 5. doi: 10.1089/ten.TEB.2017.0429. [Epub ahead of print]

Scaffold-based TMJ tissue regeneration in experimental animal models: a systematic review.

Helgeland E¹, Shanbhag S², Pedersen TO³, Mustafa K⁴, Rosén A⁵.

Abstract

Reconstruction of degenerated temporomandibular joint (TMJ) structures remains a clinical challenge. Tissue engineering (TE) is a promising alternative to current treatment options where the TMJ is either left without functional components, or replaced with autogenous, allogenic, or synthetic grafts. The objective of this systematic review was to answer the focused question: in experimental animal models, does the implantation of biomaterial scaffolds loaded with cells and/or growth factors (GFs) enhance regeneration of the discal or osteochondral TMJ tissues, compared to scaffolds alone, without cells or GFs? Following PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analysis) guidelines, electronic databases were searched for relevant controlled preclinical in vivo studies. Thirty studies reporting TMJ TE strategies in both small- (rodents, rabbits; n=25) and large-animals (dogs, sheep, goats; n=5) reporting histologic and/or radiographic outcomes were included. Twelve studies reported ectopic (subcutaneous) implantation models in rodents, while 18 studies reported orthotopic, surgically-induced defect models in large animals. On average, studies presented with an unclear-to-high risk of bias. In most studies, mesenchymal stem cells or chondrocytes were used in combination with either natural or synthetic polymer scaffolds, aiming for either TMJ disc or condyle regeneration. In summary, the overall preclinical evidence [ectopic (n=6) and orthotopic TMJ models (n=6)] indicates that addition of chondrogenic and/or osteogenic cells to biomaterial scaffolds enhances the potential for TMJ tissue regeneration. Standardization of animal models and quantitative outcome evaluations (biomechanical, biochemical, histomorphometric and radiographic) in future studies, would allow more reliable comparisons and increase the validity of the results.