The use of Fluorohydroxyapatite:

Wang L, Zhang H, Deng Y, Luo Z, Liu X, Wei S. Study of oral microbial adhesion and biofilm formation on the surface of nano-fluorohydroxyapatite/polyetheretherketone composite. Zhonghua Kou Qiang Yi Xue Za Zhi. 2015 Jun;50(6):378-82. 

Abstract. Objective: To develop novel polyetheretherketone (PEEK) based nanocomposites which possess the favorable antibacterial property, and to investigate the oral microbial adhesion and biofilm formation on the surfaces of PEEK, nano-fluorohydroxyapatite (n-FHA)-PEEK and nano-hydroxyaptite (n-HA)-PEEK. Methods: The bacterial adhesion and biofilm formation on the surfaces of n-FHA-PEEK, n-HA-PEEK were investigated via microbial viability assay kit and laser scanning confocal microscope (LSCM), respectively, with pure PEEK as control group.....Conclusions: The combination of n-HA, especially for the n-FHA could inhibit the bacteria adhesion and accelerate the bacterial death, eventually may have an influence on the structure of biofilms and reduce the risk of peri-implantitis. Therefore, n-FHA-PEEK nanocomposites presented a good prospect for clinical applications as dental implant materials.

Tahriri M, Moztarzadeh F. Preparation, characterization, and in vitro biological evaluation of PLGA/nano-fluorohydroxyapatite (FHA) microsphere-sintered scaffolds for biomedical applications. Appl Biochem Biotechnol. 2014 Mar;172(5):2465-79. doi: 10.1007/s12010-013-0696-y. 

Abstract. In this research, the novel three-dimensional (3D) porous scaffolds made of poly(lactic-co-glycolic acid) (PLGA)/nano-fluorohydroxyapatite (FHA) composite microspheres was prepared and characterize for potential bone repair applications. We employed a microsphere sintering method to produce 3D PLGA/nano-FHA scaffolds composite microspheres. The mechanical properties, pore size, and porosity of the composite scaffolds were controlled by varying parameters, such as sintering temperature, sintering time, and PLGA/nano-FHA ratio. The experimental results showed that the PLGA/nano-FHA (4:1) scaffold sintered at 90 °C for 2 h demonstrated the highest mechanical properties and an appropriate pore structure for bone tissue engineering applications. Furthermore, MTT assay and alkaline phosphatase activity (ALP activity) results ascertained that a general trend of increasing in cell viability was seen for PLGA/nano-FHA (4:1) scaffold sintered at 90 °C for 2 h by time with compared to control group. Eventually, obtained experimental results demonstrated PLGA/nano-FHA microsphere-sintered scaffold deserve attention utilizing for bone tissue engineering.

Tahriri M, Moztarzadeh F. Preparation, characterization, and in vitro biological evaluation of PLGA/nano-fluorohydroxyapatite (FHA) microsphere-sintered scaffolds for biomedical applications. Appl Biochem Biotechnol. 2014 Mar;172(5):2465-79. doi: 10.1007/s12010-013-0696-y. 

Abstract. In this research, the novel three-dimensional (3D) porous scaffolds made of poly(lactic-co-glycolic acid) (PLGA)/nano-fluorohydroxyapatite (FHA) composite microspheres was prepared and characterize for potential bone repair applications. We employed a microsphere sintering method to produce 3D PLGA/nano-FHA scaffolds composite microspheres. The mechanical properties, pore size, and porosity of the composite scaffolds were controlled by varying parameters, such as sintering temperature, sintering time, and PLGA/nano-FHA ratio. The experimental results showed that the PLGA/nano-FHA (4:1) scaffold sintered at 90 °C for 2 h demonstrated the highest mechanical properties and an appropriate pore structure for bone tissue engineering applications. Furthermore, MTT assay and alkaline phosphatase activity (ALP activity) results ascertained that a general trend of increasing in cell viability was seen for PLGA/nano-FHA (4:1) scaffold sintered at 90 °C for 2 h by time with compared to control group. Eventually, obtained experimental results demonstrated PLGA/nano-FHA microsphere-sintered scaffold deserve attention utilizing for bone tissue engineering.

Borzabadi-Farahani A, Borzabadi E, Lynch E. Nanoparticles in orthodontics, a review of antimicrobial and anti-caries applications. Acta Odontol Scand. 2014 Aug;72(6):413-7. doi: 10.3109/00016357.2013.859728. 

Abstract. Nanoparticles (NPs) are insoluble particles smaller than 100 nm in size. In order to prevent microbial adhesion or enamel demineralization in orthodontic therapy, two broad strategies have been used. These are incorporating certain NPs into orthodontic adhesives/cements or acrylic resins (nanofillers, silver, TiO2, SiO2, hydroxyapatite, fluorapatite, fluorohydroxyapatite) and coating surfaces of orthodontic appliances with NPs (i.e. coating bracket surfaces with a thin film of nitrogen-doped TiO2). Although the use of NPs in orthodontics can offer new possibilities, previous studies investigated the antimicrobial or physical characteristic over a short time span, i.e. 24 hours to a few weeks, and the limitations of in vitro studies should be recognized. Information on the long-term performance of orthodontic material using nanotechnology is lacking and necessitates further investigation and so do possible safety issues (toxicity), which can be related to the NP sizes

Zhao H, Wang F, Chen X, Wei Z, Yu D, Jiang Z. The formation mechanism of the beta-TCP phase in synthetic fluorohydroxyapatite with different fluorine contents. Biomed Mater. 2010 Aug;5(4):045011. doi: 10.1088/1748-6041/5/4/045011. 

Abstract. Synthetic hydroxyapatite (HAP) and fluorohydroxyapatite (F(x)AP) products may form the beta-tricalcium phosphate (beta-TCP) phase in a calcination process. The beta-TCP phase has a greater tendency for degradation in vivo than HAP and F(x)AP. Hence, controlling the content of the beta-TCP phase in the apatite is a pivotal factor to affect their lifetime and stability in vivo. It is particularly important to explore the formation mechanism of the beta-TCP phase in synthetic apatite. In this work, F(x)AP products with a chemical composition of Ca(10)(PO(4))(6)(OH)(2-x)F(x) are synthesized, with x = 0, 0.4, 0.8, 1.2, 1.6 and 2.0, using a precipitation method and a calcination process. The effect of fluorine substitution for hydroxyl is investigated by using x-ray diffraction analysis, Fourier transform infrared spectroscopy, and thermogravimetry and differential thermal analysis. The results show that addition of fluorine forms F(x)AP that exhibits high thermal stability. The beta-TCP phase produced as a result of the structural refinement by heat treatment is gradually reduced and dramatically suppressed with the fluorine content.

Lee CY, Rohrer MD, Prasad HS, Stover JD, Suzuki JB. Sinus grafting with a natural fluorohydroxyapatite for immediate load: a study with histologic analysis and histomorphometry. J Oral Implantol. 2009;35(4):164-75. doi: 10.1563/1548-1336-35.4.164.

Abstract. The goal of this retrospective study was to evaluate the survival rates of dental implants placed in sinuses grafted with a 50:50 composite ratio of autogenous bone and a natural flourohydroxyapatite (FHA) combined with platelet-rich plasma (PRP) using an immediate-load protocol. The authors hypothesized that a 50:50 composite ratio of FHA and autogenous bone combined with PRP would permit immediate loading without compromising implant survival rates. Eleven patients with bilateral partial edentulism of the posterior maxilla were enrolled in this retrospective study. Autogenous bone used in the graft procedure was harvested from the tibia of the left lower extremity. Each patient was grafted with a 50:50 composite ratio of autogenous bone and FHA. Membranes were not used to cover the lateral wall osteotomy site. Platelet-rich plasma was added to the graft material to accelerate and enhance bone regeneration. Four to 6 months after the grafting procedure, 37 hydroxyapatite-coated dental implants were surgically placed and immediately loaded between 72 hours and 5 days later with custom titanium abutments and acrylic provisional restorations placed out of functional occlusion. Six months later, definitive ceramometal restorations were cemented on to the custom abutments. Patients were observed over a 52-week period. The overall implant survival rate was 97.3%. Histologic and histomorphometric analysis of core samples revealed formation of new vital bone in different graft specimens ranging from 23% to 34%. In each core bone sample, 100% of the bone sample was determined to be vital. In the grafted maxillary sinus, the natural FHA combined with autogenous bone in a 50:50 composite ratio with PRP is a suitable graft material permitting immediate load without compromising implant survival rates while decreasing the overall healing time.

Klongnoi B, Rupprecht S, Kessler P, Zimmermann R, Thorwarth M, Pongsiri S, Neukam FW, Wiltfang J, Schlegel KA. Lack of beneficial effects of platelet-rich plasma on sinus augmentation using a fluorohydroxyapatite or autogenous bone: an explorative study. J Clin Periodontol. 2006 Jul;33(7):500-9. doi: 10.1111/j.1600-051X.2006.00938.x. 

Abstract. Background: Maxillary sinus augmentation is frequently necessary before placement of dental implants in the posterior maxilla. Besides autogenous bone graft, various bone substitutes have been used, with favourable results. Although platelet-rich plasma (PRP) has been used in the field of oral and maxillofacial surgery for years, its beneficial effects on osseous regeneration still remain unclear. The aim of this study was to evaluate the short and long time effects of PRP on single-stage sinus augmentation using autogenous bone or a fluorohydroxyapatite (Algipore) in a randomized prospective animal study....Results: The grafting materials chosen showed increasing levels of BIC and newly formed bone throughout the period of observation in both PRP and non-PRP groups. Adding PRP resulted in lower BIC and newly formed bone compared with autogenous bone grafts or Algipore alone. However, a statistical significance was not found. The percentages of the remaining bone substitute in both the PRP and non-PRP groups were closely comparable in all observation periods. Conclusions: The application of PRP could not reveal significant beneficial effects on the BIC, the percentage of the newly formed bone and the remaining bone substitute in this study.

Schopper C, Moser D, Sabbas A, Lagogiannis G, Spassova E, König F, Donath K, Ewers R. The fluorohydroxyapatite (FHA) FRIOS Algipore is a suitable biomaterial for the reconstruction of severely atrophic human maxillae. Clin Oral Implants Res. 2003 Dec;14(6):743-9. doi: 10.1046/j..2003.00959.x. 

Abstract. Grafting of the maxillary sinus is an established treatment modality to provide sufficient bone for the fixation of dental implants. We stated the hypothesis that the porous fluorohydroxyapatitic (FHA) biomaterial FRIOS Algipore could be used as a suitable biomaterial for sinus grafting in severely atrophic maxillae. To investigate the accuracy of our hypothesis, 69 trephine specimens from 26 patients who received maxillary sinus grafting with FRIOS Algipore were retrieved during the installation of dental implants. The specimens were processed undecalcified and subjected to histomorphological and histomorphometrical examination. After a mean healing time of 7 months, 23.0% (+/-8.3) new bone had formed around the implanted particles. Bone formation was also evident within the pores of the particles. Statistical analysis indicated that bone formation originated from the sinus floor. Particles provided scaffolding for the promotion of newly formed bone towards apical sinus portions. Mineral dissolution from the walls of the pores was observed prior to and during bone apposition. Thereafter, portions of the particles were resorbed during bone remodeling and replaced by newly formed bone. The present investigation shows that the biomaterial FRIOS Algipore is a suitable biomaterial for sinus grafting of severely atrophic maxillae.

Effects of incorporation of nano-fluorapatite or nano-fluorohydroxyapatite on a resin-modified glass ionomer cement.
Lin J, Zhu J, Gu X, Wen W, Li Q, Fischer-Brandies H, Wang H, Mehl C.
Acta Biomater. 2011 Mar;7(3):1346-53. doi: 10.1016/j.actbio.2010.10.029.

Alshemary AZ, Pazarçeviren EA, Dalgic AD, Tezcaner A, Keskin D, Evis Z. Nanocrystalline Zn2+ and SO42- binary doped fluorohydroxyapatite: A novel biomaterial with enhanced osteoconductive and osteoinconductive properties. Mater Sci Eng C Mater Biol Appl. 2019 Nov;104:109884. doi: 10.1016/j.msec.2019.109884. Epub 2019 Jun 12. PMID: 31500005.