Biomaterials, Current Strategies, and Novel Nano-Technological Approaches for Periodontal Regeneration

Abstract

Periodontal diseases involve injuries to the supporting structures of the tooth and, if left untreated, can lead to the loss of the tooth. Regenerative periodontal therapies aim, ideally, at healing all the damaged periodontal tissues and represent a significant clinical and societal challenge for the current ageing population. This review provides a picture of the currently-used biomaterials for periodontal regeneration, including natural and synthetic polymers, bioceramics (e.g., calcium phosphates and bioactive glasses), and composites. Bioactive materials aim at promoting the regeneration of new healthy tissue. Polymers are often used as barrier materials in guided tissue regeneration strategies and are suitable both to exclude epithelial down-growth and to allow periodontal ligament and alveolar bone cells to repopulate the defect. The problems related to the barrier postoperative collapse can be solved by using a combination of polymeric membranes and grafting materials. Advantages and drawbacks associated with the incorporation of growth factors and nanomaterials in periodontal scaffolds are also discussed, along with the development of multifunctional and multilayer implants. Tissue-engineering strategies based on functionally-graded scaffolds are expected to play an ever-increasing role in the management of periodontal defects.

Keywords: bioactivity; bioceramics; composites; dental implants; dental materials; nanomaterials; nanotechnology; periodontal tissue engineering; polymers.

Figure 1

Schematic representation of the key parameters involved in the periodontal regeneration.

Figure 2

Schematic representation of an engineered ceramic scaffold developed for peri-prosthetic infection prevention. The functionalization of the ceramic scaffold with a pectin-chitosan hydrogel allows the control of antibiotic release, inhibits bacterial proliferation and biofilm formation, and promotes osteoblast proliferation. Optical and scanning electron microscopy pictures courtesy of Giorgio Iviglia.

Figure 3

In vitro cell response of a ceramic granulate (Synergoss^®; see also [116]) coated with a biomimetic collagen layer. This ‘bio-design’ approach improves the expression of osteogenic markers and reduces the inflammation response by macrophages.

Figure 4

Schematic representation of a layer-by-layer surface treatment in which collagen fibrils are combined with hyaluronic acid and vancomycin. This multifunctional surface elicits a sustained antibacterial activity and a pro-osteogenic response (see also [222]).

Figure 5

Moldable composite scaffold (pectin/chitosan hydrogel + biphasic calcium phosphate particles) for alveolar bone regeneration: the material promotes osteoblast adhesion and proliferation with a 3-fold higher ALP gene expression at one week compared to the control. Reproduced with permission from [225].

Figure 6

Li-doped MBGs for potential use in periodontal regeneration: SEM analysis of 0Li-MBG (a), 2Li-MBG (b), and 5Li-MBG (c) scaffolds before and after seeding of human periodontal ligament-derived cells (hPDLCs) on them. Reproduced with permission from [224].

Figure 7

Effects of Li-doped MBG scaffolds on the expression of some of the bone-related genes such as ALP (a), OPN (b), OCN (d), cementum-specific markers of CEMP1 (c), and CAP (e) for hPDLCs. *: significant difference (p < 0.05) for the 5Li-MBG group in comparison to the other two groups at day 3. **: significant difference (p < 0.05) for the 5Li-MBG group in comparison to the other two groups at day 7. Reproduced with permission from [224].