Radiographic outcomes of lateral sinus floor elevation at sites without perforations and sites with perforations managed with a resorbable membrane: A retrospective study.

AIM: To evaluate the radiographic outcomes of lateral sinus floor elevation with simultaneous implant placement at sites without sinus membrane perforation (SMP) and sites with SMP managed with a resorbable membrane. MATERIALS AND METHODS: One hundred and thirty-nine patients and 170 implants (56 perforation, 114 non-perforation) were included. Cone-beam computed tomography (CBCT) images were taken before surgery (T0), immediately after surgery (T1) and 6 months after surgery (T2). Post-operative augmentation parameters, including endo-sinus bone gain (ESBG) along the implant axis, mean new bone height (NBH) surrounding the implant and augmentation volume (AV), were measured at T1 and T2. RESULTS: At T1, there were no significant differences in ESBG, NBH and AV between the two groups. At T2, although ESBG did not significantly differ between the two groups, NBH (8.50 ± 1.99 mm vs. 9.99 ± 2.52 mm, p = .039) and AV (519.37 ± 258.38 mm3 vs. 700.99 ± 346.53 mm3, p < .001) were significantly lower in the perforation group. The shrinkage of graft material from T1 to T2, including ΔESBG (p = .002), ΔNBH (p < .001) and ΔAV (p < .001), was higher in the perforation group. CONCLUSIONS: SMP during LSFE with simultaneous implant placement is associated with greater resorption of the grafted area at a 6-month follow-up.

Bone alteration and esthetics associated with implant-supported prostheses in the anterior maxilla under different implant placement timing: A retrospective clinical study of 1 to 3 years.

STATEMENT OF PROBLEM: Different factors influence alterations in facial bone thickness and esthetic outcomes after implant placement. Whether the timing of implant placement influences alterations in the bone dimensional and esthetic outcomes is unclear. PURPOSE: The purpose of this retrospective clinical study was to assess the influence of the timing of implant placement on alveolar bone alterations and esthetic outcome. MATERIAL AND METHODS: Data were collected from 40 patients who had received guided bone regeneration (GBR) performed simultaneously with immediate, early, or delayed single-tooth implant placement in the anterior maxilla. Facial and palatal horizontal bone thicknesses (FHBT, PHBT) and vertical bone level (FVBL, PVBL) immediately after surgery (T0), at 6 months after implant placement (T1), and at 1 to 3 years follow-up (T2) were measured, and the changes calculated. The pink esthetic score (PES) and white esthetic score (WES) were evaluated at the 1- to 3-year follow-up. The Kruskal-Wallis followed by the Dunn t test was applied to evaluate bone alteration among groups, and the Bonferroni method was used for adjusting multiple comparisons. The 1-way ANOVA test was used to determine any significance in the esthetic outcome in the 3 groups (α=.05). RESULTS: The reduction in the FHBT0 of the immediate, early, and delayed implant placement group (T2-T0) was -1.17 (-1.70, -0.61) mm, -1.53 (-1.69, -0.49) mm, and -1.47 (-2.30, -0.20) mm, respectively. The FHBT around the implant apices remained basically stable. No obvious changes in the PHBT around the implants of the immediate and delayed implant placement group were noted. The FVBL significantly decreased in each group during the follow-up period (-1.34 (01.88, -0.56) mm, immediate; -2.88 (-3.79, -1.07) mm, early; -1.26 (-2.52, -0.48) mm, delayed). The PVBL change in the early implant placement group (-2.18 (-3.26, -0.86) mm) was more significant than that in the immediate (-0.55 (-2.10, -0.17) mm) and delayed (-0.51 (-1.29, 0.02) mm) implantation groups (P =.013). The mean ±standard deviation PES/WES score of the immediate (15.6 ±1.84) and early (15.00 ±1.13) implant placement groups was higher than that of the delayed implant placement group (13.92 ±2.10) without significant difference. CONCLUSIONS: Similar bone changes and esthetic outcomes were found around implants of the immediate, early, and delayed implant placement groups.

Hair-Bearing Expanded Scalp Flap for Total Beard Reconstruction in Patients With Chin and Submental Postburn Scars.

BACKGROUND: Loss of beard in adult male caused by severe burn may cause cosmetic and psychological problems for these patients. Reconstruction of the beard with hair-bearing skin flaps in similar color and texture of the surrounding tissues remains a challenge. METHODS: Eight male patients suffered from submental postburn scar and beard loss were treated by using the hair-bearing expanded scalp flap. A 1000 mL nephroid tissue expander was first implanted under the frontal and mid scalp. After a 3 to 4-month tissue expansion, the expanded hair-bearing scalp flap based on bilateral superficial temporal vessels were raised and transferred for beard reconstruction, and the cutaneous pedicles were curled into tubes. Delay and division of the pedicles were performed 3 to 4 weeks after flap transfer. RESULTS: Eight male patients with postburn scar and beard loss were successfully treated with no major complication. One patient suffered from edge necrosis at distal end of the flap and healed after daily dressing change. Chin and submental areas were repaired by expanded scalp flap and total beard was reconstructed at the same time. All donor sites were closed directly without skin grafting. CONCLUSIONS: The modified expanded bipedicled scalp flap provides an easy and reliable way for total beard reconstruction and large-scale submental scars repairment.

Establishment of a Novel Mouse Model for Soft Tissue Expansion.

BACKGROUND: Despite its increasing use, not much is known about tissue expansion, and its complication rates are significantly high. Thus, there is an urgent need to establish a stable animal model to overcome the limitations and complications of tissue expansion. Although the mouse model has shown several advantages in the in-depth studies, an appropriate mouse expansion model has rarely been reported, likely because of its loose skin. MATERIALS AND METHODS: A micro expander was designed and implanted under the scalp of a mouse (expanded group); sterilized saline was regularly injected into the expander. In sham-operated mice (control group), a silicone sheet was implanted under the scalp. Skin samples were collected 5 wk after surgery. Histologic changes including epidermal and dermal thickness and collagen fiber arrangement were analyzed. In addition, vascular density and cell proliferation ratio were determined. An ultrastructural analysis was also performed. RESULTS: With the application of the expansion device, the skin became tight and showed area enlargement. The epidermal thickness of the expanded skin increased significantly (P < 0.01), whereas the thickness of the dermis decreased significantly (P < 0.05) as compared with the control skin. Masson staining demonstrated that collagen bundles were arranged more compactly in the expanded skin (P < 0.05) than in the controls. Furthermore, more proliferating cells (P < 0.05) and blood vessels (P < 0.01) were observed. Transmission electron microscopy showed that the fibers of expanded skin were stretched and broken into bundles of various diameters, with abundant active fibroblasts. CONCLUSIONS: A reliable mouse model of scalp skin expansion was successfully established, which may be a promising tool for in-depth studies on skin soft tissue expansion.

Ureteral anastomosis with a polyimide stent in rat kidney transplantation.

Background: Complications associated with ureteral anastomosis in kidney transplantation are highly prevalent, despite the development of various types of stents. The current stent materials and placement methods have several limitations. This study attempts to provide an alternative by investigating ureteral anastomosis with a polyimide stent and a modified placement method in a rat model of kidney transplantation.Methods: Sprague-Dawley rats were randomly divided into Group I: sham operation, Group II: autologous ureteral anastomosis, and Group III: isogenic kidney transplantation with ureteral anastomosis. For the anastomosis, a polyimide stent with a previously placed 11-0 silk was inserted into the ureter. The stent and ureter were fixed with 11-0 silk sutures. The kidney weight and serum creatinine were recorded. The ureteral and renal sections were taken for histological analysis.Results: None of the stents had migrated. Urethral patency was achieved. Further, there were no evident histological changes in the anastomosed ureters. The serum creatinine level in group III was significantly higher than the other two groups, but there was no significant difference in kidney weight among the groups at postoperative week 12. Finally, the histological structure of kidneys in groups II and III only showed minor changes.Conclusions: The current anastomosis method with polyimide stent causes minimal damage to the ureteral walls and minimizes the possibility of stent migration. Therefore, this method of ureteral anastomosis with the polyimide stent should be explored for its potential benefits in more animal kidney transplantation models, thus providing an alternative for the clinical setting.

The Influence of Cellulosic Polymer's Variables on Dissolution/Solubility of Amorphous Felodipine and Crystallization Inhibition from a Supersaturated State.

The collective impact of cellulosic polymers on the dissolution, solubility, and crystallization inhibition of amorphous active pharmaceutical ingredients (APIs) is still far from being adequately understood. The goal of this research was to explore the influence of cellulosic polymers and incubation conditions on enhancement of solubility and dissolution of amorphous felodipine, while inhibiting crystallization of the drug from a supersaturated state. Variables, including cellulosic polymer type, amount, ionic strength, and viscosity, were evaluated for effects on API dissolution/solubility and crystallization processes. Water-soluble cellulosic polymers, including HPMC E15, HPMC E5, HPMC K100-LV, L-HPC, and MC, were studied. All cellulosic polymers could extend API dissolution and solubility to various extents by delaying crystallization and prolonging supersaturation duration, with their effectiveness ranked from greatest to least as HPMC E15 > HPMC E5 > HPMC K100-LV > L-HPC > MC. Decreased polymer amount, lower ionic strength, or higher polymer viscosity tended to decrease dissolution/solubility and promote crystal growth to accelerate crystallization. HPMC E15 achieved greatest extended API dissolution and maintenance of supersaturation from a supersaturated state; this polymer thus had the greatest potential for maintaining sustainable API absorption within biologically relevant time frames.

[Clinical study of modified suspension reduction method combined with percutaneous vertebroplasty in the treatment of thoracolumbar osteoporotic compression fracture].

OBJECTIVE: To investigate the clinical effect of modified suspension reduction method combined with percutaneous vertebroplasty in the treatment of osteoporotic thoracolumbar compression fractures. METHODS: From February 2020 to October 2021, 92 patients with thoracolumbar osteoporotic compression fracture were treated by percutaneous vertebroplasty. According to different treatment methods, they were divided into the observation group and the control group. The observation group was treated with modified suspension reduction and then percutaneous vertebroplasty, while the control group was treated with percutaneous vertebroplasty alone. The observation group (47 cases), including 20 males and 27 females, the age ranged from 59 to 76 years old with an average of (69.74±4.50) years old, fractured vertebral bodies:T10(2 cases), T11(7 cases), T12(19 cases), L1(14 cases), L2(5 cases);the control group(45 cases), including 21 males and 24 females, the age ranged from 61 to 78 years old with an average of (71.02±3.58) years old, fractured vertebral bodies:T10(3 cases), T11(8 cases), T12(17 cases), L1(12 cases), L2(5 cases);The leakage of bone cement were observed, the visual analogue scale (VAS), Oswestry lumbar dysfunction index (ODI), anterior vertebrae height (AVH), Cobb angle of kyphosis and the amount of bone cement injected before and after operation were recorded and compared between the two groups. RESULTS: All patients were followed up, ranged from 6 to10 with an average of (8.45±1.73) months. Two patients ocurred bone cement leakage in observation group and 3 patients in control group. AVH of observation group increased (P<0.05) and Cobb angle of injured vertebrae decreased (P<0.05). Cobb angle of injured vertebrae and AVH of the control group were not significantly changed (P>0.05). Cobb angle of injured vertebrae of the observation group was lower than that of control group (P<0.05) and AVH was higher than that of the control group (P<0.05). In the observation group, VAS before operation and 1 week, 3 and 6 months after operation respectively were(7.32±1.05) scores, (3.56±1.18) scores, (1.83±0.67) scores, (1.27±0.34) scores, and ODI were(40.12±14.69) scores, (23.76±10.19) scores, (20.15±6.39) scores, (13.45±3.46) scores. In the control group, VAS before operation and 1 week, 3 and 6 months after operation respectively were(7.11±5.26) scores, (3.82±0.68) scores, (1.94±0.88) scores, (1.36±0.52) scores, and ODI were(41.38±10.23) scores, (25.13±14.22) scores , (20.61±5.82) scores, (14.55±5.27) scores . The scores of VAS and ODI after operation were lower than those before operation (P<0.05), but there was no significant difference between the two groups (P<0.05). CONCLUSION: Modified suspension reduction method combined with PVP surgery for osteoporotic thoracolumbar compression fractures has achieved good clinical results, which can effectively relieve lumbar back pain, restore vertebral height, correct kyphosis, improve lumbar function and patients' quality of life.

Montelukast Attenuates Retraction of Expanded Flap by Inhibiting Capsule Formation around Silicone Expander through TGF-ß1 Signaling.

BACKGROUND: Tissue expansion has tremendous applications in plastic surgery, but flap retraction provides insufficient tissue for use. Inspired by the use of montelukast to suppress capsular contracture, the authors investigated the effects of montelukast on capsule formation around the expander and retraction of the expanded scalp of the rat. METHODS: Thirty-six male Sprague-Dawley rats were randomly divided into control and montelukast groups. In each group, 12 expanded flaps with or without capsules were harvested for histologic and molecular analysis; the six remaining expanded flaps were transferred to repair defects. Myofibroblast and transforming growth factor-ß1 expression in the capsule was determined using immunofluorescence. Capsule ultrastructure was observed using transmission electron microscopy. Related protein expression in the capsules was detected using Western blot analysis. RESULTS: A comparison of control and montelukast groups revealed that areas of the harvested expanded flaps with capsules were greater (2.04 ± 0.11 cm 2 versus 2.42 ± 0.12 cm 2 , respectively; P = 0.04); the retraction rate decreased (41.3% ± 2.16% versus 28.13% ± 2.17%, respectively; P < 0.01). However, the increased areas and decreased retraction disappeared after capsule removal. The number of myofibroblasts declined. Thin, sparse collagen fibers were observed in the capsules. The expression of COL1, COL3, TGF-ß1, EGR1, and phosphorylated ERK1/2 in the capsules decreased. Furthermore, the recipient area repaired by the transferred expanded flap was increased from 4.25 ± 0.39 cm 2 to 6.58 ± 0.31 cm 2 ( P < 0.01). CONCLUSION: Montelukast attenuates retraction of the expanded flap by inhibiting capsule formation through suppressing transforming growth factor-ß1 signaling. CLINICAL RELEVANCE STATEMENT: This study provides novel insights into a method for increasing the area of the expanded flap.

Septal extension graft for correcting short nose in East Asians: review of autologous cartilage grafts and postoperative stability.

Septal extension grafts (SEGs) are widely used to correct a short nose in Asians, but few studies to our knowledge have investigated the relationship between different graft materials and the stability of the aesthetic results in East Asians. In this review we discuss the performance of autologous cartilage grafts, with a focus on the critical factors for achieving a stable postoperative nose shape, and propose algorithms for graft material selection in treating Asian patients. Avoiding harvesting septal cartilage grafts and preserving the whole cartilage is helpful for maintaining tip support over the long term. For patients who have loose nasal skin, a cartilage framework with no significant defect, or a mildly short nose, autogenous conchal cartilage is an effective and stable material for primary rhinoplasty. Costal cartilage has good performance and is suitable for treating severe nasal deformities and revision surgery.

Electrochemical deposition of lithium coating on titanium implant with enhanced early stage osseointegration.

Recently, a large number of studies have reported that lithium (Li) displayed a positive effect on osteogenesis. However, only a few studies have investigated the Li-incorporated surfaces through electrochemical deposition. In this study, electrochemical deposition was conducted on a CHI600E electrochemical workstation. The characterization of electrochemical deposition (ECD) and ECD-Li surfaces were detected by field-emission scanning electron microscopy with energy-dispersive spectrometer. rBMSCs were cultured on two surfaces for subsequent adhesion, proliferation and live/dead assay. To evaluate the effects of Li-incorporated implants by electrochemical deposition on osseointegration in vivo, teeth extraction of two premolars and one first molar in bilateral mandible were performed on six male beagle dogs. After 3 months, ZDI and ZDI-Li implants were inserted into the bilateral mandible of each beagle dog. Micro Computed Tomography (Micro-CT) and hard tissue sectioning analysis were carried out to evaluate the osseointegration at 4- and 8-weeks post-implantation. Results showed that ECD-Li surface promoted adhesion and proliferation of BMSCs in the early stage. More importantly, through micro-CT analysis, the values of bone volume/total volume (BV/TV) (0.374 ± 0.015), bone-implant contact (BIC) (0.831 ± 0.025), and Tb.Th (0.412 ± 0.007) in ZDI-Li group was significantly higher than those of ZDI group (0.302 ± 0.009, 0.700 ± 0.023, 0.353 ± 0.001, p < .01) at 4 weeks. Similarly, ZDI-Li group manifested more bone contact with the implant surfaces at 4 weeks based on hard tissue sectioning analysis, whereas no significant difference was detected between two groups at 8 weeks. Therefore, incorporating Li into implant surface through ECD could enhance early osseointegration in vivo.

Antifouling poly(PEGMA) grafting modified titanium surface reduces osseointegration through resisting adhesion of bone marrow mesenchymal stem cells.

As an alternative strategy to achieve the desired bone augmentation, tenting screw technology (TST) has considerably broadened the indications for implant treatment. Titanium tenting screws are typically used in TST to maintain the space for bone regeneration. However, a high degree of osteogenic integration complicate titanium tenting screw removal and impact the bone healing micro-environment. Previous efforts have been focused on modifying titanium surfaces to enhance osseointegration while ignoring the opposite process. Due to the vital role of bone marrow mesenchymal stem cells (BMSCs) in bone regeneration, it might be feasible to reduce osseointegration around titanium tenting screws by resisting the adhesion of BMSCs. Herein, poly(ethylene glycol)methyl ether methacrylate (poly(PEGMA)) with an optimal length of PEG chain was incorporated with a Ti surface in terms of surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (SI-ARGET ATRP). The cell apoptosis analysis showed that the new surface would not induce the apoptosis of BMSCs. Then, the adhesive and proliferative behaviors of BMSCs on the surface were analyzed which indicated that the poly(PEGMA) surface could inhibit the proliferation of BMSCs through resisting the adhesion process. Furthermore, in vivo experiments revealed the presence of the poly(PEGMA) on the surface resulted in a lower bone formation and osseointegration compared with the Ti group. Collectively, this dense poly(PEGMA) surface of Ti may serve as a promising material for clinical applications in the future. STATEMENT OF SIGNIFICANCE: The poly(ethylene glycol)methyl ether methacrylate (poly(PEGMA)) with an optimal length of PEG chain was grafted onto a Ti surface by surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (SI-ARGET ATRP). The PEGMA surface could reduce the osteogenic integration by preventing the adhesion of cells, resulting in a lower pullout force of the modified implant and thereby desirable and feasible applications in dental surgery.

Development of rabbit meniscus acellular matrix.

OBJECTIVE: To prepare a rabbit meniscus acellular matrix scaffold and explore the histomorphological and biomechanical properties of the scaffold. METHODS: Rabbit meniscuses were collected and acellularized using a modified eight-step detergent process with hydrogen peroxide, distilled water, Triton X-100, and sodium deoxycholate. Its color and texture were observed. Histomorphological assessment was performed using routine hematoxylin-eosin stain, toluidine blue stain, Saffron stain, Hoechst-33258 stain, and immunohistochemical staining of collagen I. The ultrastructure of the specimens was observed with inverted phase contrast microscopy. Transient recovery rate of deformation, maximal recovery rate of deformation, and maximal compressive strength were tested to determine the biomechanical properties of the scaffold. RESULTS: The processed meniscus was milk-white in color with loose structure. It histologically appeared cell-free, stained positively for collagen I, and had abundant micropores according to phase-contrast microscopy. The transient recovery rate of deformation was (76.65∓4.61)%, the maximal recovery rate of deformation was 100%, and the maximal compressive strength was (4.51∓0.69) N when the specimens were compressed 40%. CONCLUSIONS: The rabbit meniscus acellular matrix scaffold, with numerous micropores, is easy to be recovered from deformation and suitable for the adhesiveness and growth of breeding cells. This scaffold can be used as an ideal implant for future tissue engineering of the meniscus.

Study on the effect of surface characteristics of short-pulse laser patterned titanium alloy on cell proliferation and osteogenic differentiation.

Concise, low-cost preparation of titanium alloy implants with high cell proliferation and osteogenic differentiation is urgently needed. Nanosecond laser ablation of titanium alloy has the advantages of short processing time, less pollution, and non-contact. In this research, we adopt a nanosecond UV laser to process the closed groove and cross groove titanium alloys with length to width ratio of 1:1, 2.5:1, 4:1, and 6:1. The surface morphology, surface roughness, phase, element distribution, surface chemistry, and wettability were characterized. The effect of the patterned surface's properties on the adhesion, proliferation, and osteogenic differentiation of stem cells was studied. The results show the laser-ablated lattice structure's surface energy can increase rapidly in the natural environment. The cell adhesion of stem cells on a lattice structure with low roughness and high surface energy is optimal. The element concentration at the ablated edges is higher than at the bottom under Marangoni and surface tension. Stem cells preferentially adhere to the ablated edges with high roughness, element concentration, and hardness. Cell differentiation is chiefly affected by patterning structure. On the surface of the boss structure with a length to width ratio of 2.5:1, the proportion of cell length to diameter is about 2.5, and the cell area is greater. The osteogenic differentiation of cells is the highest on the surface.

Picosecond laser texturing on titanium alloy for biomedical implants in cell proliferation and vascularization.

Introducing specific textures to titanium alloy implant surface is helpful to modify the surface properties of materials. In this article, biomedical TC4 (Ti-6Al-4V) alloy was textured by a 10-ps infrared laser. Laser parameters that directly affected the detailed dimension of textures and its characteristics were optimized within laser power, defocusing amount, and scanning parameters via response surface methodology. These textures consisted of groove array about 30-90 µm in depth and 100 µm in width were prepared and their surface property (including surface morphology, element composition, wetting behavior, and biocompatibility) was analyzed. Surface characteristic analysis indicated that picosecond laser texturing improved surface properties and biocompatibility mainly by altering the microstructure and morphology of materials. In addition, laser textured groove array promoted contact area and hydrophobicity of material surface. Cell culture experiments and animal studies showed that titanium alloy implants with 30- and 60-µm-deep groove arrays on the surface-enhanced cell proliferation and adhesion. Meanwhile, compared to the polished samples, these groove arrays promoted the growth of new blood vessels and enhanced the combination of blood vessel and implants in vivo. That is, the deeper groove array was, and the better vascularizing effect the blood vessel exhibited.

ATRAID regulates the action of nitrogen-containing bisphosphonates on bone.

Nitrogen-containing bisphosphonates (N-BPs), such as alendronate, are the most widely prescribed medications for diseases involving bone, with nearly 200 million prescriptions written annually. Recently, widespread use of N-BPs has been challenged due to the risk of rare but traumatic side effects such as atypical femoral fracture (AFF) and osteonecrosis of the jaw (ONJ). N-BPs bind to and inhibit farnesyl diphosphate synthase, resulting in defects in protein prenylation. Yet, it remains poorly understood what other cellular factors might allow N-BPs to exert their pharmacological effects. Here, we performed genome-wide studies in cells and patients to identify the poorly characterized gene, ATRAID Loss of ATRAID function results in selective resistance to N-BP-mediated loss of cell viability and the prevention of alendronate-mediated inhibition of prenylation. ATRAID is required for alendronate inhibition of osteoclast function, and ATRAID-deficient mice have impaired therapeutic responses to alendronate in both postmenopausal and senile (old age) osteoporosis models. Last, we performed exome sequencing on patients taking N-BPs that suffered ONJ or an AFF. ATRAID is one of three genes that contain rare nonsynonymous coding variants in patients with ONJ or an AFF that is also differentially expressed in poor outcome groups of patients treated with N-BPs. We functionally validated this patient variation in ATRAID as conferring cellular hypersensitivity to N-BPs. Our work adds key insight into the mechanistic action of N-BPs and the processes that might underlie differential responsiveness to N-BPs in people.

Effect of the Wnt signal-RANKL/OPG axis on the enhanced osteogenic integration of a lithium incorporated surface.

Bone remolding involves the formation of new bone by osteoblasts and the absorption of old bones by osteoclasts. Due to the vital role of osteoblasts and osteoclasts during bone regeneration, it might be feasible to promote osseointegration around the titanium implants by stimulating osteoblasts and inhibiting osteoclasts by modifying the surfaces of the implants. Lithium is used in the treatment of psychiatric patients, and it may be associated with osteogenesis. In this study, lithium was incorporated with sandblasted, large-grit and acid-etched titanium implants via a hydrothermal treatment. In vitro, the nano-scale surface enhanced the adhesion and proliferation of bone marrow mesenchymal stem cells (BMSCs). Moreover, the SLA-Li surface displayed a negative effect on the process of osteoclastogenesis. Further mechanism analysis indicated that the canonical Wnt/ß-catenin signaling pathway was activated according to the results of RT-PCR and western blotting. More importantly, the RANKL/OPG signaling axis was also involved in these effects on the SLA-Li surface. The experiments in vivo proved that the SLA-Li surface could induce the bone formation and osseointegration during the early osseointegration after the dental implant surgery. These results suggested that bone homeostasis could be manipulated by an SLA-Li surface, which implied that this new surface might serve as a promising material for clinical application in the future.

Double helical conformation and extreme rigidity in a rodlike polyelectrolyte.

The ubiquitous biomacromolecule DNA has an axial rigidity persistence length of ~50 nm, driven by its elegant double helical structure. While double and multiple helix structures appear widely in nature, only rarely are these found in synthetic non-chiral macromolecules. Here we report a double helical conformation in the densely charged aromatic polyamide poly(2,2'-disulfonyl-4,4'-benzidine terephthalamide) or PBDT. This double helix macromolecule represents one of the most rigid simple molecular structures known, exhibiting an extremely high axial persistence length (~1 micrometer). We present X-ray diffraction, NMR spectroscopy, and molecular dynamics (MD) simulations that reveal and confirm the double helical conformation. The discovery of this extreme rigidity in combination with high charge density gives insight into the self-assembly of molecular ionic composites with high mechanical modulus (~ 1 GPa) yet with liquid-like ion motions inside, and provides fodder for formation of other 1D-reinforced composites.