Growth factor delivery for oral and periodontal tissue engineering

Abstract

The treatment of oral and periodontal diseases and associated anomalies accounts for a significant proportion of the healthcare burden, with the manifestations of these conditions being functionally and psychologically debilitating. Growth factors are critical to the development, maturation, maintenance and repair of craniofacial tissues, as they establish an extracellular environment that is conducive to cell and tissue growth. Tissue-engineering principles aim to exploit these properties in the development of biomimetic materials that can provide an appropriate microenvironment for tissue development. These materials have been constructed into devices that can be used as vehicles for delivery of cells, growth factors and DNA. In this review, different mechanisms of drug delivery are addressed in the context of novel approaches to reconstruct and engineer oral- and tooth-supporting structures, namely the periodontium and alveolar bone.

Figure 1. Gene therapy approaches

A. DNA and growth factors can be delivered to cells through different mechanisms, including direct injection to an in vivo site, transport to a site via a carrier matrix, or introduced ex vivo prior to cell transplantation. B. Genetic material can be transferred into cells using different vectors, the most common of which are plasmids, retroviruses, adenoviruses and adeno-associated viruses. C. Growth factor delivery by gene therapy strategies aim to modulate cell proliferation, migration, matrix synthesis and differentiation.

Figure 2. Specific examples of different strategies for tissue engineering craniofacial tissues

A. Growth factor delivery via an injectable system to stimulate regeneration of the cartilaginous articular disc of the temporomandibular joint. B. Cell transplantation of salivary gland cells on polymer scaffolds to restore a functionally deficient salivary gland. C. Combined approach of cell transplantation and growth factor delivery for bone regeneration using a growth factor-releasing scaffold as a cell carrier for osteo-progenitor cells. D. Gene therapy approach employed to regenerate the periodontium of a periodontal defect resulting from periodontal disease. E. Cell therapy approach using bone precursor cells as an autogenous bone graft to enable the placement of dental implants in an area that is commonly deficient in bone (below the maxillary sinus).