Novel rechargeable calcium phosphate nanoparticle-containing orthodontic cement

White spot lesions （WSLs）, due to enamel demineralization, occur frequently in orthodontic treatment. We recently developed a novel rechargeable dental composite containing nanoparticles of amorphous calcium phosphate （NACP） with long-term calcium （Ca） and phosphate （P） ion release and caries-inhibiting capability. The objectives of this study were to develop the first NACP- rechargeable orthodontic cement and investigate the effects of recharge duration and frequency on the efficacy of ion re-release. The rechargeable cement consisted of pyromellitic glycerol dimethacrylate （PMGDM） and ethoxylated bisphenol A dimethacrylate （EBPADMA）. NACP was mixed into the resin at 40% by mass. Specimens were tested for orthodontic bracket shear bond strength （SBS） to enamel, Ca and P ion initial release, recharge and re-release. The new orthodontic cement exhibited an SBS similar to commercial orthodontic cement without CaP release （P〉 0.1）. Specimens after one recharge treatment （e.g., 1 min immersion in recharge solution repeating three times in one day, referred to as ＂1 min 3 times＂） exhibited a substantial and continuous re-release of Ca and P ions for 14 days without further recharge. The ion re-release did not decrease with increasing the number of recharge/re-release cycles （P〉 0.1）. The ion re-release concentrations at 14 days versus various recharge treatments were as follows： 1 min 3 times〉3 min 2 times〉 1 min 2 times〉6 min 1 time〉3 min 1 time〉 1 min 1 time. In conclusion, although previous studies have shown that NACP nanocomposite remineralized tooth lesions and inhibited caries, the present study developed the first orthodontic cement with Ca and P ion recharge and long-term release capability. This NACP-rechargeable orthodontic cement is a promising therapy to inhibit enamel demineralization and WSLs around orthodontic brackets.

Calcium phosphate cements for bone engineering and their biological properties

Calcium phosphate cements （CPCs） are frequently used to repair bone defects. Since their discovery in the 1980s, extensive research has been conducted to improve their properties, and emerging evidence supports their increased application in bone tissue engineering. Much effort has been made to enhance the biological performance of CPCs, including their biocompatibility, osteoconductivity, osteoinductivity, biodegradability, bioactivity, and interactions with cells. This review article focuses on the major recent developments in CPCs, including 3D printing, injectability, stem cell delivery, growth factor and drug delivery, and pre- vascularization of CPC scaffolds via co-culture and tri-culture techniques to enhance angiogenesis and osteogenesis.

Biointerface engineering nanoplatforms for cancer-targeted drug delivery

Over the past decade,nanoparticle-based therapeutic modalities have become promising strategies in cancer therapy.Selective delivery of anticancer drugs to the lesion sites is critical for elimination of the tumor and an improved prognosis.Innovative design and advanced biointerface engineering have promoted the development of various nanocarriers for optimized drug delivery.Keeping in mind the biological framework of the tumormicroenvironment,biomembrane-camouflaged nanoplatforms have been a research focus,reflecting their superiority in cancer targeting.In this review,we summarize the development of various biomimetic cell membrane-camouflaged nanoplatforms for cancertargeted drug delivery,which are classified according to the membranes fromdifferent cells.The challenges and opportunities of the advanced biointerface engineering drug delivery nanosystems in cancer therapy are discussed.

Dentin-desensitizing biomaterials

Dentin hypersensitivity(DH)associated with dentinal tubule exposure is one of the most common causes of toothache with a rapid onset and short duration.Medication,filling repair,laser irradiation,crown therapy,and desensitizing toothpaste are standard clinical treatment strategies,but unsatisfactory treatment modalities are marked by long-term administration,poor dentinal tubule closure,microleakage,and the development of secondary caries.To improve the treatment efficiency of DH,numerous organic or inorganic biomaterials have been developed to relieve toothache and reverse the instability of desensitization.Biomaterials are expected to participate in dental remineralization to achieve desensitization.This review discusses various biomaterials for DH therapy based on different desensitization mechanisms,including dentinal tubule closure and dental nerve blockade,and presents a perspective on the underlying future of dentin regeneration medicine for DH therapy.

Functional biomaterials for comprehensive periodontitis therapy

Periodontitis is an inflammatory disease caused by bacterial infection directly, and the dysregulation of host immune-inflammatory response finally destroys periodontal tissues. Current treatment strategies for periodontitis mainly involve mechanical scaling/root planing(SRP), surgical procedures,and systemic or localized delivery of antimicrobial agents. However, SRP or surgical treatment alone has unsatisfactory long-term effects and is easy to relapse. In addition, the existing drugs for local periodontal therapy do not stay in the periodontal pocket long enough and have difficulties in maintaining a steady, effective concentration to obtain a therapeutic effect, and continuous administration always causes drug resistance. Many recent studies have shown that adding bio-functional materials and drug delivery systems upregulates the therapeutic effectiveness of periodontitis. This review focuses on the role of biomaterials in periodontitis treatment and presents an overview of antibacterial therapy, host modulatory therapy, periodontal regeneration, and multifunctional regulation of periodontitis therapy. Biomaterials provide advanced approaches for periodontal therapy, and it is foreseeable that further understanding and applications of biomaterials will promote the development of periodontal therapy.