3D-Printed Multifunctional Ag/CeO2/ZnO Reinforced Hydroxyapatite-Based Scaffolds with Effective Antibacterial and Mechanical Properties.

Conventional three-dimensional (3D)-printed hydroxyapatite (HA)-based constructs have limited utility in bone tissue engineering due to their poor mechanical properties, elevated risk of microbial infection, and limited pore interconnectivity. 3D printing of complex multiple components to fabricate fully interconnected scaffolds is a challenging task; here, in this work, we have developed a procedure for fabrication of printable ink for complex systems containing multinanomaterials, i.e., HAACZ (containing 1 wt % Ag, 4 wt % CeO2, and 6 wt % ZnO) with better shear thinning and shape retention properties. Moreover, 3D-printed HAACZ scaffolds showed a modulus of 143.8 GPa, a hardness of 10.8 GPa, a porosity of 59.6%, effective antibacterial properties, and a fully interconnected pore network to be an ideal construct for bone healing. Macropores with an average size of ∼469 and ∼433 µm within the scaffolds of HA and HAACZ and micropores with an average size of ∼0.6 and ∼0.5 µm within the strut of HA and HAACZ were developed. The distribution of fully interconnected micropores was confirmed using computerized tomography, whereas the distribution of micropores within the strut was visualized using Voronoi tessellation. The water contact angle studies revealed the most suitable hydrophilic range of water contact angles of ∼71.7 and ∼76.6° for HA and HAACZ, respectively. HAACZ scaffolds showed comparable apatite formation and cytocompatibility as that of HA. Antibacterial studies revealed effective antibacterial properties for the HAACZ scaffold as compared to HA. There was a decrease in bacterial cell density for HAACZ from 1 × 105 to 1.2 × 103 cells/mm2 against Gram-negative (Escherichia coli) and from 1.9 × 105 to 5.6 × 103 bacterial cells/mm2 against Gram-positive (Staphylococcus aureus). Overall, the 3D-printed HAACZ scaffold resulted in mechanical properties, comparable to those of the cancellous bone, interconnected macro- and microporosities, and excellent antibacterial properties, which could be utilized for bone healing.

Triple Function of Amelogenin Peptide-Chitosan Hydrogel for Dentin Repair.

Biomimetic strategies like peptide-guided collagen mineralization promise to enhance the effectiveness of dentin remineralization. We recently reported that rationally designed amelogenin-derived peptides P26 and P32 promoted apatite nucleation, mineralized collagen, and showed potential in enamel regrowth and dentin remineralization. To facilitate the clinical application of amelogenin-derived peptides and to uncover their effectiveness in repairing dentin, we have now implemented a chitosan (CS) hydrogel for peptide delivery and have investigated the effects of P26-CS and P32-CS hydrogels on dentin remineralization using 2 in situ experimental models that exhibited different levels of demineralization. The efficacy of the peptide-CS hydrogels in dentin repair was evaluated by characterizing the microstructure, mineral density, mineral phase, and nanomechanical properties of the remineralized samples. The new strategy of atomic force microscopy PeakForce quantitative nanomechanical mapping was used for direct visualization and nanomechanical analysis of repaired dentin lesions across the lesion depth. Results from the 2 models indicated the potential triple functions of peptide-CS hydrogels for dentin repair: building a highly organized protective mineralized layer on dentin, occluding dentinal tubules by peptide-guided in situ mineralization, and promoting biomimetic dentinal collagen remineralization. Importantly, peptides released from the CS hydrogel could diffuse into the dentinal matrix and penetrate the dentinal tubules, leading to both surface and subsurface remineralization and tubule occlusion. Given our previous findings on peptide-CS hydrogels' potential for remineralizing enamel, we see further promise for hydrogels to treat tooth defects involving multiple hard tissues, as in the case of noncarious cervical lesions.

Quantitative Description of Isomorphism in the Series of Simple Compounds.

The introduction of the notion of energy change resulting from the ion exchange in apatites leads to the question: how can some simple isomorphic series be described using the mentioned idea? We concentrated on the simple isomorphic series of compounds: apatite, bioapatite, calcite, aragonite, celestine, K-, Zn- and Cu-Tutton's salts. It was demonstrated in all the series, except Tutton's salts, that the change in energy and the change in the crystal cell volume are, in a simple way, dependent on the change in the ionic radii of the introduced ions. The linear relationships between the variations in energy and in the universal crystallographic dimension d were derived from the earlier equations and proven based on available data. In many cases, except the Tutton's salts, linear dependence was discovered between the change in energy and the sinus of universal angle Θ, corresponding to the change in momentum transfer. In the same cases, linear dependencies were observed between the energy changes and the changes in the volumes of crystallographic cells, and mutually between changes in the crystallographic cell volume V, crystallographic dimension d, and diffraction angle Θ.

Development of a new biomaterial based on cashew tree gum (Anarcadium occidentale L.) enriched with hydroxyapatite and evaluation of cytotoxicity in adipose-derived stem cell cultures.

Cashew tree gum is a polysaccharide material highly available in the Northeast region of Brazil. It has been explored for biocompatibility with human tissues. This research aimed to describe the synthesis and characterization of cashew gum/hydroxyapatite scaffold and evaluate the possible cytotoxicity in murine adipose-derived stem cells (ADSCs) cultures. ADSCs of the subcutaneous fat tissue of Wistar rats were collected, isolated, expanded, differentiated into three strains, and characterized immunophenotypically. The scaffolds were synthesized through chemical precipitation, lyophilized and characterized through scanning electron microscopy (SEM), infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermal analysis (TG and DTG), and mechanical testing. The scaffold presented a crystalline structure and pores with an average diameter of 94.45 ± 50.57 µm. By mechanical tests, the compressive force and modulus of elasticity were like the cancellous bone. The isolated adipose-derived stem cells (ADSCs) presented fibroblast morphology, adhesion capacity to plastic, differentiation in osteogenic, adipogenic and chondrogenic lineages, positive expression for the CD105 and CD90 markers and negative expression for the CD45 and CD14 markers. The MTT test showed increased cell viability, and the biomaterial showed a high level of hemocompatibility (<5 %). This study allowed the development of a new scaffold for future surgical applicability in tissue regeneration.

Marine-Inspired Approaches as a Smart Tool to Face Osteochondral Regeneration.

The degeneration of osteochondral tissue represents one of the major causes of disability in modern society and it is expected to fuel the demand for new solutions to repair and regenerate the damaged articular joints. In particular, osteoarthritis (OA) is the most common complication in articular diseases and a leading cause of chronic disability affecting a steady increasing number of people. The regeneration of osteochondral (OC) defects is one of the most challenging tasks in orthopedics since this anatomical region is composed of different tissues, characterized by antithetic features and functionalities, in tight connection to work together as a joint. The altered structural and mechanical joint environment impairs the natural tissue metabolism, thus making OC regeneration even more challenging. In this scenario, marine-derived ingredients elicit ever-increased interest for biomedical applications as a result of their outstanding mechanical and multiple biologic properties. The review highlights the possibility to exploit such unique features using a combination of bio-inspired synthesis process and 3D manufacturing technologies, relevant to generate compositionally and structurally graded hybrid constructs reproducing the smart architecture and biomechanical functions of natural OC regions.

Synthesis and Densification of Mo/Mg Co-Doped Apatite-type Lanthanum Silicate Electrolytes with Enhanced Ionic Conductivity.

Apatite-type lanthanum silicate (LSO) electrolyte is one of the most promising candidates for developing intermediate-temperature solid oxide electrolysis cells and solid oxide full cells (IT-SOECs and SOFCs) due to its stability and low activation energy. However, the LSO electrolyte still suffers from unsatisfied ionic conductivity and low relative density. Herein, a new co-doped method is reported to prepare highly purified polycrystalline powders of Mg-Mo co-doped LSO (Mg/Mo-LSO) electrolytes with high excellent densification properties and improved ionic conductivity. Introducing the Mo6+ and Mg2+ ions into the LSO structure can increase the number of interstitial oxide ions and improve the degree of densification at lower sintering temperatures, more importantly, expand the migration channel of oxide ions to enhance the ionic conductivity. As a result, the relative density of the fabricated Mo/Mg-LSO electrolytes pellets could achieve more than 98 % of the theoretical density after sintering at 1500 °C for 4 h with a grain size of about 1-3 µm and the EIS results showed the ionic conductivity increased from 0.782 mS ⋅ cm-1 for the pristine LSO to 33.94 mS ⋅ cm-1 for the doped sample La9.5 Si5.45 Mg0.3 Mo0.25 O26+δ at 800 °C. In addition, the effect of different Mo6+ doping contents was investigated systematically, in which La9.5 Si5.45 Mg0.3 Mo0.25 O26+δ possessed the highest ionic conductivity and relative density. The proposed Mo/Mg co-doped method in this work is one step forward in developing apatite-structured electrolytes offering excellent potential to address the common issues associated with the fabrication of dense, highly conductive, and thermochemically stable electrolytes for solid oxide electrolysers and fuel cells.

Measurements of Energetic States Resulting from Ion Exchanges in the Isomorphic Crystals of Apatites and Bioapatites.

Developments in the field of nanostructures open new ways for designing and manufacturing innovative materials. Here, we focused on new original ways of calculating energy changes during the substitution of foreign ions into the structure of apatites and bioapatites. Using these tools, the energetic costs of ion exchanges were calculated for the exemplary cases known from the literature. It was established that the most costly were ion exchanges of some cations inside apatites and of anions, and the least costly exchanges in tetrad channel positions. Real energy expenses for bioapatites are much smaller in comparison to mineral apatites due to the limited involvement of magnesium and carbonates in the structure of hard tissues. They are of the order of several electron volts per ion. The rigorous dependences of the energy changes and crystallographic cell volumes on the ionic radii of introduced cations were proved. The differentiation of the positioning of foreign ions in locations of Ca(I) and Ca(II) could be calculated in the case of a Ca-Pb reaction in hydroxyapatite. The energetic effects of tooth aging were indicated. The ability of energy change calculation during the ion exchange for isomorphic substances widens the advantages resulting from X-ray diffraction measurements.

Crystallographic and Physicochemical Analysis of Bovine and Human Teeth Using X-ray Diffraction and Solid-State Nuclear Magnetic Resonance.

Dental research often uses bovine teeth as a substitute for human teeth. The aim of this study was to evaluate differences in the crystalline nanostructures of enamel and dentin between bovine and human teeth, using X-ray diffraction (XRD) and solid-state nuclear magnetic resonance (NMR). The crystallite size (crystallinity) and microstrains were analyzed using XRD with the Rietveld refinement technique and the Halder-Wagner method. The 31P and 1H NMR chemical environments were analyzed by two-dimensional (2D) 1H-31P heteronuclear-correlation (HETCOR) magic-angle spinning (MAS) NMR spectroscopy. Enamel had a greater crystallite size and fewer microstrains than dentin for both bovine and human teeth. When compared between the species, the bovine apatite had a smaller crystallite size with more microstrains than the human apatite for both dentin and enamel. The 2D HETCOR spectra demonstrated that a water-rich layer and inorganic HPO4- ions were abundant in dentin; meanwhile, the hydroxyl group in the lattice site was more dominant in enamel. A greater intensity of the hydroxyl group was detected in human than in bovine for both dentin and enamel. For 31P projections, bovine dentin and bovine enamel have wider linewidths than human dentin and human enamel, respectively. There are differences in the crystallite profile between human and bovine. The results of dental research should be interpreted with caution when bovine teeth are substituted for human teeth.

Hierarchy of Bioapatites.

Apatites are one of the most intensively studied materials for possible biomedical applications. New perspectives of possible application of apatites correspond with the development of nanomaterials and nanocompounds. Here, an effort to systematize different kinds of human bioapatites forming bones, dentin, and enamel was undertaken. The precursors of bioapatites and hydroxyapatite were also considered. The rigorous consideration of compositions and stoichiometry of bioapatites allowed us to establish an order in their mutual sequence. The chemical reactions describing potential transformations of biomaterials from octacalcium phosphate into hydroxyapatite via all intermediate stages were postulated. Regardless of whether the reactions occur in reality, all apatite biomaterials behave as if they participate in them. To conserve the charge, additional free charges were introduced, with an assumed meaning to be joined with the defects. The distribution of defects was coupled with the values of crystallographic parameters "a" and "c". The energetic balances of bioapatite transformations were calculated. The apatite biomaterials are surprisingly regular structures with non-integer stoichiometric coefficients. The results presented here will be helpful for the further design and development of nanomaterials.

Luminescent Citrate-Functionalized Terbium-Substituted Carbonated Apatite Nanomaterials: Structural Aspects, Sensitized Luminescence, Cytocompatibility, and Cell Uptake Imaging.

This work explores the preparation of luminescent and biomimetic Tb3+-doped citrate-functionalized carbonated apatite nanoparticles. These nanoparticles were synthesized employing a citrate-based thermal decomplexing precipitation method, testing a nominal Tb3+ doping concentration between 0.001 M to 0.020 M, and a maturation time from 4 h to 7 days. This approach allowed to prepare apatite nanoparticles as a single hydroxyapatite phase when the used Tb3+ concentrations were (i) ≤ 0.005 M at all maturation times or (ii) = 0.010 M with 4 h of maturation. At higher Tb3+ concentrations, amorphous TbPO4·nH2O formed at short maturation times, while materials consisting of a mixture of carbonated apatite prisms, TbPO4·H2O (rhabdophane) nanocrystals, and an amorphous phase formed at longer times. The Tb3+ content of the samples reached a maximum of 21.71 wt%. The relative luminescence intensity revealed an almost linear dependence with Tb3+ up to a maximum of 850 units. Neither pH, nor ionic strength, nor temperature significantly affected the luminescence properties. All precipitates were cytocompatible against A375, MCF7, and HeLa carcinogenic cells, and also against healthy fibroblast cells. Moreover, the luminescence properties of these nanoparticles allowed to visualize their intracellular cytoplasmic uptake at 12 h of treatment through flow cytometry and fluorescence confocal microscopy (green fluorescence) when incubated with A375 cells. This demonstrates for the first time the potential of these materials as nanophosphors for living cell imaging compatible with flow cytometry and fluorescence confocal microscopy without the need to introduce an additional fluorescence dye. Overall, our results demonstrated that Tb3+-doped citrate-functionalized apatite nanoparticles are excellent candidates for bioimaging applications.

Use of nano-hydroxyapatite serum and different finishing/polishing techniques to reduce enamel staining of debonding after orthodontic treatment : A randomized clinical trial.

PURPOSE: The aim of this study was to assess the effect of nano-hydroxyapatite serum and different finishing, polishing techniques on color alterations of enamel caused by debonding procedures after comprehensive orthodontic treatment by use of a spectrophotometer. METHODS: This randomized clinical trial recruited 20 participants with previous non-extraction orthodontic treatment and acceptable hygiene to evaluate enamel staining after orthodontic debonding. The usage of a carbide bur alone, as the conventional method, and the combination use of carbide burs and Sof-Lex discs (3M™ ESPE, St. Paul, MN, USA) were compared to each other followed by 10 days application of nano-hydroxyapatite after debonding. Then the enamel staining was evaluated by a reflectance spectrophotometer in three periods: immediately, and 2 and 4 months after debonding. RESULTS: The comparison of the groups showed a significant interaction between Sof-Lex groups and the control side after the first interval of the study (p = 0.042). Application of nano-hydroxyapatite demonstrated no significant difference in color parameters between upper and lower arches of the participants at all intervals of this study (p > 0.05). The mean total color change (ΔE) in all groups and between all intervals had been clinically perceptible (ΔE > 3.3). CONCLUSIONS: The applied concentrations of nano-hydroxyapatite had no significant effect in reducing tooth color changes after debonding in orthodontic treatment. Sof-Lex discs can significantly reduce tooth color changes in a short time.

Fabrication and characterization of a bioactive polymethylmethacrylate-based porous cement loaded with strontium/calcium apatite nanoparticles.

Polymethylmethacrylate (PMMA)-based cements are used for bone reparation due to their biocompatibility, suitable mechanical properties, and mouldability. However, these materials suffer from high exothermic polymerization and poor bioactivity, which can cause the formation of fibrous tissue around the implant and aseptic loosening. Herein, we tackled these problems by adding Sr2+ -substituted hydroxyapatite nanoparticles (NPs) and a porogenic compound to the formulations, thus creating a microenvironment suitable for the proliferation of osteoblasts. The NPs resembled the structure of the bone's apatite and enabled the controlled release of Sr2+ . Trends in the X-ray patterns and infrared spectra confirmed that Sr2+ replaced Ca2+ in the whole composition range of the NPs. The inclusion of an effervescent additive reduced the polymerization temperature and lead to the formation of highly porous cement exhibiting mechanical properties comparable to the trabecular bone. The formation of an opened and interconnected matrix allowed osteoblasts to penetrate the cement structure. Most importantly, the gas formation confined the NPs at the surface of the pores, guaranteeing the controlled delivery of Sr2+ within a concentration sufficient to maintain osteoblast viability. Additionally, the cement was able to form apatite when immersed into simulated body fluids, further increasing its bioactivity. Therefore, we offer a formulation of PMMA cement with improved in vitro performance supported by enhanced bioactivity, increased osteoblast viability and deposition of mineralized matrix assigned to the loading with Sr2+ -substituted hydroxyapatite NPs and the creation of an interconnected porous structure. Altogether, our results hold promise for enhanced bone reparation guided by PMMA cements.

Biomorphic Transformations: A Leap Forward in Getting Nanostructured 3-D Bioceramics.

Obtaining 3-D inorganic devices with designed chemical composition, complex geometry, hierarchic structure and effective mechanical performance is a major scientific goal, still prevented by insurmountable technological limitations. With particular respect to the biomedical field, there is a lack in solutions ensuring the regeneration of long, load-bearing bone segments such as the ones of limbs, due to the still unmet goal of converging, in a unique device, bioactive chemical composition, multi-scale cell-conducive porosity and a hierarchically organized architecture capable of bearing and managing complex mechanical loads in a unique 3D implant. An emerging, but still very poorly explored approach in this respect, is given by biomorphic transformation processes, aimed at converting natural structures into functional 3D inorganic constructs with smart mechanical performance. Recent studies highlighted the use of heterogeneous gas-solid reactions as a valuable approach to obtain effective transformation of natural woods into hierarchically structured apatitic bone scaffolds. In this light, the present review illustrates critical aspects related to the application of such heterogeneous reactions when occurring in the 3D state, showing the relevance of a thorough kinetic control to achieve controlled phase transformations while maintaining the multi-scale architecture and the outstanding mechanical performance of the starting natural structure. These first results encourage the further investigation towards the biologic structures optimized by nature along the ages and then the development of biomorphic transformations as a radically new approach to enable a technological breakthrough in various research fields and opening to still unexplored industrial applications.

Synthesis and characterization of silver substituted strontium phosphate silicate apatite using solid-state reaction for osteoregenerative applications.

Strontium phosphosilicate is one of the fastest-growing apatite in bone regeneration application due to the presence of strontium and silica components in the parent materials. However, bacterial infections cause setbacks to the bone regeneration process often leading to surgical revisions, and is a big issue that needs to be addressed. Silver on this front has proven to be a great substituent as seen in the case of calcium phosphate-based ceramics that addresses the bactericidal properties of a biomaterial. Apatite strontium phosphosilicate substituted with a stoichiometric amount of silver as a dopant was synthesized using a high-temperature solid-state reaction. The phase formation was characterized by XRD and FT-IR coupled with morphological features visualized using Electron Microscopy. Antibacterial properties were investigated quantitatively using Colony-forming unit method against both Gram-positive as well as Gram-negative bacteria. Cytotoxicity assay was performed against MG-63 Cell lines and it showed excellent biocompatibility at 25ug/ml with optimal doping of 2% silver. Further, apatite seeding and formation were characterized after immersion in simulated body fluid solution which showed apatite phase formation initiated after 4 days of treatment characterized by XRD and FT-IR studies. This apatite formation was also visualized and confirmed using SEM.

Structural phase formation and in vitro bioactivity evaluations of strontium phosphosilicate for orthopedic applications.

Structural features of apatites make them one of the most promising candidates for bone tissue regenerative applications. The unique structure and availability of mobile Metal ion as well as other components help interaction with biological fluids and can promote as well as stimulate bone regeneration with correct components. The present study focusses on Strontium phosphosilicate, an apatite analogue to Calcium phosphate-based HAP only loaded with better composition replacing Calcium with stimulatory Strontium and co-existent Silicate alongside phosphate both known to stimulate osteogenesis. Bulk particles were synthesized as powders with Acidic medium as well as the Basic medium of reaction mixture via Sol-Gel and Co-precipitation techniques respectively and phase formation was studied with respect to temperature further detailed by TGA-DSC studies. Secondary phases were also indexed based on which Acidic medium samples sintered at 800°C were comparatively better from the Basic medium on account of the presence of silicate phase forming agglomerated Strontium phosphosilicate. Hemolysis assay and MG-63 based cytotoxicity assay were carried out to study biocompatibility and antibacterial properties were also elucidated in Gram-positive and Gram-negative bacteria. Apatite seeding and bone mineralization studies were carried out with Simulated body fluid and characterized structurally and morphologically.

Thermodynamic and thermoelastic data of georesources raw minerals: Zinc sulphide and apatite.

This article reports a dataset on the thermodynamic and elastic properties of two important raw minerals exploited in georesources and ore mining. The presented data refers to two zinc sulphide polymorphs, namely zinc-blende (low-pressure polymorph, space group F 4 - 3 m ) and rock-salt (high-pressure polymorph, space group F m 3 - m ) [1], and of type-A carbonated apatite, [CAp, Ca10(PO4)6CO3, space group P1] [2]. The data here reported were calculated from ab initio quantum mechanical simulations at the DFT/B3LYP level, all-electron Gaussian-type orbitals basis sets and from the analysis of the phonon properties of the zinc sulphide polymorphs and of type-A CAp by means of the quasi-harmonic approximation. In addition, a correction to take into account the effects of dispersive forces was considered to obtain the dataset of type-A carbonated apatite. This dataset, which was validated against experimental thermodynamic data reported in literature, has been employed to construct the phase diagram between the two zinc sulphide polymorphs and discuss their stability over the temperature and pressure range 0-800 K and 0-25 GPa. The thermodynamic and thermoelastic data of CAp were obtained between 0 and 600 K and 0-3 GPa, below the temperature of thermal decomposition of the mineral. The reported data can be of use in several application fields, for instance fundamental georesource exploration and exploitation, and also in applied mineralogy, geology, material science, and as a reference to assess the quality of other theoretical approaches. Furthermore, the data of type-A carbonated apatite could be useful for designing and processing new biomaterials with tailored properties.

Vibrational spectral fingerprinting for chemical recognition of biominerals.

Pathologies associated with calcified tissue, such as osteoporosis, demand in vivo and/or in situ spectroscopic analysis to assess the role of chemical substitutions in the inorganic component. High energy X-ray or NMR spectroscopies are impractical or damaging in biomedical conditions. Low energy spectroscopies, such as IR and Raman techniques, are often the best alternative. In apatite biominerals, the vibrational signatures of the phosphate group are generally used as fingerprint of the materials although they provide only limited information. Here, we have used first principles calculations to unravel the complexity of the complete vibrational spectra of apatites. We determined the spectroscopic features of all the phonon modes of fluoroapatite, hydroxy-apatite, and carbonated fluoroapatite beyond the analysis of the phosphate groups, focusing on the effect of local corrections induced by the crystalline environment and the specific mineral composition. This provides a clear and unique reference to discriminate structural and chemical variations in biominerals, opening the way to a widespread application of non-invasive spectroscopies for in vivo diagnostics, and biomedical analysis.

Novel Approach to Tooth Chemistry: Quantification of Human Enamel Apatite in Context for New Biomaterials and Nanomaterials Development.

A series of linear profiles of the elements of the enamel in human molar teeth were made with the use of an electron microprobe and a Raman microscope. It is postulated that the enamel can be treated as the superposition of variable "overbuilt" enamel on the stable "core" enamel at the macro-, micro- and nanoscale level. The excessive values characterize the "overbuilt enamel". All the profiles of excessive parameters along the enamel thickness from the enamel surface to the dentin enamel junction (DEJ) can be approximated very precisely with the use of exponential functions, where Ca, P, Cl and F spatial profiles are decaying while Mg, Na, K and CO32- ones are growing distributions. The "overbuilt" apatite formed on the boundary with DEJ, enriched in Na, Mg, OH and carbonates, reacts continuously with Ca, Cl and F, passing into an acid-resistant form of the "overbuilt" enamel. The apparent phases arriving in boundary regions of the "overbuilt enamel" were proposed. Microdiffraction measurements reveal relative variation of energy levels during enamel transformations. Our investigations are the milestones for a further new class of biomaterial and nanomaterial development for biomedical applications.

Application of low-crystalline carbonate apatite granules in 2-stage sinus floor augmentation: a prospective clinical trial and histomorphometric evaluation.

PURPOSE: The purpose of this study was to elucidate the efficacy and safety of carbonate apatite (CO3Ap) granules in 2-stage sinus floor augmentation through the radiographic and histomorphometric assessment of bone biopsy specimens. METHODS: Two-stage sinus floor augmentation was performed on 13 patients with a total of 17 implants. Radiographic assessment using panoramic radiographs was performed immediately after augmentation and was also performed 2 additional times, at 7±2 months and 18±2 months post-augmentation, respectively. Bone biopsy specimens taken from planned implant placement sites underwent micro-computed tomography, after which histological sections were prepared. RESULTS: Postoperative healing of the sinus floor augmentation was uneventful in all cases. The mean preoperative residual bone height was 3.5±1.3 mm, and this was increased to 13.3±1.7 mm by augmentation with the CO3Ap granules. The mean height of the augmented site had decreased to 10.7±1.9 mm by 7±2 months after augmentation; however, implants with lengths in the range of 6.5 to 11.5 mm could still be placed. The mean height of the augmented site had decreased to 9.6±1.4 mm by 18±2 months post-augmentation. No implant failure or complications were observed. Few inflammatory cells or foreign body giant cells were observed in the bone biopsy specimens. Although there were individual differences in the amount of new bone detected, new bone was observed to be in direct contact with the CO3Ap granules in all cases, without an intermediate layer of fibrous tissue. The amounts of bone and residual CO3Ap were 33.8%±15.1% and 15.3%±11.9%, respectively. CONCLUSIONS: In this first demonstration, low-crystalline CO3Ap granules showed excellent biocompatibility, and bone biopsy showed them to be replaced with bone in humans. CO3Ap granules are a useful and safe bone substitute for two-stage sinus floor augmentation.Trial Registration: ICTRP Identifier: JPRN-UMIN000019281.

A randomised clinical trial on the efficacy of 5% fluorocalcium phosphosilicate-containing novel bioactive glass toothpaste.

Dentine hypersensitivity (DH) is a common and harrowing dental condition. A novel BioMin-F technology that contains 5% fluorocalcium phosphosilicate bioactive glass has been introduced. It forms fluorapatite, which is more stable towards acid erosion. There is a lack of literature with the utility of this toothpaste in treating DH. Therefore, the authors of this randomised clinical trial have aimed to compare and evaluate the efficacy of 5% fluorocalcium phosphosilicate with an 8% arginine and calcium carbonate and placebo toothpaste. A total of 75 patients clinically diagnosed with DH were randomly divided into three groups: Group A, 5% fluorocalcium phosphosilicate; Group B, 8% arginine and calcium carbonate; and Group C, placebo. The DH was evaluated by tactile and evaporative stimuli, and a visual analogue scale (VAS) was used for evaporative stimuli at pre-baseline, baseline (15 days) and post-baseline (1 month). The results showed symptoms of DH were reduced in all three groups. However, Group A showed a better reduction of DH than the other two groups. The toothpaste containing 5% fluorocalcium phosphosilicate was reported to be more efficacious than the other two toothpastes in managing DH. This novel development opens up a unique opportunity in the prevention and management of DH and may also be beneficial in preventing acid erosion of the tooth surface and in the maintenance of oral hygiene by reducing the effects of plaque accumulation and gingival inflammation.