Progress of surface modifications of temporary anchorage devices: a review

Temporary anchorage devices (TADs) have evolved as useful anchorage providers for orthodontic tooth movements. To improve the stability of TADs, a number of modifications on their surface have been developed and investigated. This review comprehensively summarizes recent findings of clinically applied surface modifications of TADs and compared the biological improvement of these modifications. We focused on sandblasting, large-grit, acid etching (SLA), anodic oxidation (AO) and ultraviolet photofunctionalization (UVP). In vitro, in vivo and clinical studies of these surface modifications on TADs with clear explanations, low possibility of bias and published in English were included. Studies demonstrated that SLA, AO and UVP enhance cell attachment, proliferation, and differentiation in vitro. The biocompatibility and osteoconductivity of TAD surface are improved in vivo. However, in clinical studies, the changes are generally not so impressive. Furthermore, this review highlights the promising potential in combinations of different modifications. In addition, some other surface modifications, for instance, the biomimetic calcium phosphate coating, deserve to be proposed as future strategies.