Nanotechnology and its role in the management of periodontal diseases.

With the unstoppable trend of an increasing agingpopulation in both the developing and developedcountries, scientists in the field of regenerativemedicine and tissue engineering are continuallylooking for new ways to apply the principles of celltransplantation, materials science, and bioengineer-ing to construct biological substitutes that will restoreand maintain normal function in diseased andinjured tissues (2). In addition, the development ofmore refined means of delivering medications attherapeutic levels to specific sites is an importantclinical issue. Applications of such technology indentistry, and periodontics in particular, are noexception as periodontal destruction can be found toincrease in prevalence with increasing age (42, 52).The traditional clinical procedures of scaling, rootplanning and periodontal flap surgery, if followed byan adequate postoperative supportive periodontalcare, results, in most cases, in successful manage-ment of progressive periodontal diseases (27, 62, 65).More recently, the regenerative treatment of perio-dontal defects with an agent, or procedure, hasattracted enormous interest from materials scientistsand also from both private companies and govern-ment organizations because of its considerable eco-nomic potential (4, 43) and scientific significance.One of the emerging areas is tissue engineering thatseekstodeveloptechniquesandmaterialstoaidintheformation of new tissues to replace damaged tissues(4). Guided tissue engineering has been successfullyused in the treatment intrabony defects (14) and fur-cationdefects(45,65).Amoregeneralreview oftissueengineering concepts in terms of periodontal regen-eration has been carried out by Bartold et al. (4).The necessary strategies for complete regenerationof human tissues should be the ultimate endpoint forthe field of regenerative medicine and engineering.However, for many tissues this goal remains elusive(74). Nonetheless, there has been significant progressmade in recent years with the development andintroduction of various metallic and polymericmaterials structured in nanoscales (17, 46, 75, 84) andthe development of many biomaterials that formideal interfaces with tissues (7, 84). Using naturalprocesses as a guide, substantial advances have beenmade at the interface of nanomaterials and biology,including the fabrication of nanofiber materials forthree-dimensional cell culture and tissue engineering(84). One example of such applications in the man-agement of periodontal diseases is the evaluation oftwo typical cellular components of a hard ⁄ soft tissueinterface such as the periodontal ligament ⁄ mandibleand patellar tendon ⁄ tibia (7). Tissue engineering ofsuch complex interfaces requires a contiguous scaf-fold system with at least two cell types associatedwith the engineering of both hard and soft connectivetissues.In the pharmaceutical domain, liposomes andpolymer-based micro- and nanoparticles are thesubject of current intense research and development(72). In addition, metallic particles, which were firstintroduced in the first half of the 1980s, are nowexperiencing a renaissance. A very new generation ofbiosensors based on the optical properties of col-loidal gold nanocrystals and nanoparticles is readyto be implemented in diagnosis and medical ima-ging (72) as well as tagging DNA sandwich assays(19, 57). Concerning therapeutic applications, thepotential of metallic and polymeric nanoparticles tohelp fulfill the need for timely and accurate con-trolled release of drugs can be explored by syn-thesizing materials of tailor-designed structures,such as hybrid hollow spheres (9) and core-shellstructures (11).