Effects of 16% Carbamide Peroxide on Optical Properties of Thermally Aged Monolithic CAD-CAM Glass Ceramics with Different Surface Treatments

This study aimed to investigate the effects of 16% carbamide peroxide (CP) on the relative translucency parameter (RTP) and color stability of thermally aged CAD-CAM glass-ceramics with glazing or polishing. Three different CAD-CAM blocks-feldspathic (VM), lithium disilicate (IPS), and zirconia-reinforced lithium silicate ceramic (VS)-were used in this study. The specimens were divided into two groups (n=10) according to surface treatments (glazing or polishing). Bleaching treatment with 16% CP was applied to the thermally aged specimens. A spectrophotometer (VITA Easyshade Advance) was used to measure the CIE L*a*b*coordinates of the specimens on white and black backgrounds, and RTP and color difference (ΔE00) values were calculated. The surface topography of the specimens and the atomic weight of the elements were analyzed with scanning electron microscopy and energy-dispersive x-ray. The data were analyzed by using the two-way ANOVA test for ΔE00 values and two-way repeated measures ANOVA test for RTP and color parameters values (a=0.05) and the Tukey post-hoc test was used for multiple comparisons of the groups. RTP values were statistically influenced by material type, bleaching, and finishing technique, and the interaction among these factors was found to be significant (p<0.05). ΔE00 values were statistically influenced by material type, finishing technique, and the interaction among these factors was also found to be significant (p<0.05). IPS presented significantly lower RTP and ΔE00 values for both glazed and polished surfaces (p<0.05). 16% CP bleaching agent caused changes in translucency of aged VM and IPS at different levels. Glazed surfaces presented higher color stability in comparison to mechanically polished surfaces for VS (p<0.05).

Influence of surface treatment and ageing on the bond strength of resin cement to hybrid and glass-ceramic CAD/CAM materials

The influence of different surface treatments and ageing on the shear bond strength (SBS) of computer-aided design/computer-aided manufacturing (CAD/CAM) materials is still contentious. Therefore, this study evaluated the effect of surface treatments and ageing on the SBS of resin cement to polymer-infiltrated ceramic network (PICN) and zirconia-reinforced lithium silicate (ZLS) CAD/CAM materials. Specimens of PICN (n=10) and ZLS (n=10) were submitted to four surface treatment groups: 1) 5% hydrofluoric acid etching (HF) + silanisation (SI); 2) Air abrasion (AB)+HF+SI; 3) HF + universal adhesive (UA); 4) AB+HF+SI+UA. The treated specimens were bonded with resin cement cylinders and tested in SBS after 24 h and one year of water storage. Data were assessed by "analysis of variance" (ANOVA) and Tukey test (α=0.05) and failure modes were classified. No significant differences were observed among treatments at each evaluation time (p>0.05). SBS decreased after one year of storage, except for PICN treated with HF+UA (p=0.068). Air-abraded groups displayed a lower SBS reduction for ZLS. PICN and ZLS exhibited predominantly adhesive and mixed failures, but at one year, PICN cohesive failures increased. In conclusion, HF+UA is an effective surface treatment for PICN, while the combination AB+HF+SI+UA was more appropriate for ZLS. The water storage for one year reduced the SBS for most groups.

A comprehensive technique using digital workflow to improve an unpleasant smile: A clinical report

By utilising open-source digital software, clinicians can create an integrative digital workflow composed of various technological systems. This report presents a clinical case that follows a comprehensive digital workflow to improve the smile of a 42-year-old female patient. The patient presented with minor attrition of maxillary anterior teeth and discoloured, asymmetrical composite restorations on central maxillary incisors. Her smile was rehabilitated by restoring her maxillary anterior teeth with lithium disilicate ceramic veneers. A smile design system was used to create a virtual simulation of the patient's desired treatment outcome. Utilising a 3D tooth library generated by the smile design system, extra-oral photographs, and intra-oral scans of the patient's maxillary and mandibular arches, a 3D model of the proposed smile design was created in an advanced 3D sculpting software. The resin casts that were fabricated with a 3D printer were used to fabricate a mockup and sent to the laboratory as reference for the final restoration. The specific shade recipe for the ceramic veneers was obtained using a special polar eye filter and digital shade matching software. There is no doubt that advancements in digital technology are providing clinicians with limitless treatment modalities. From intra-oral scanners and smile design systems to 3D sculpting software and even digital shade matching systems, continuous technological developments are paving the way for the complete digitalisation of dentistry. This case report presents an example of this digital revolution.

Use of a Porous Alumina Antibiotic-Loaded Ceramic to Treat Bone Defect and Bone Infection After Road Trauma

To describe the use of a porous alumina ceramic loaded with antibiotics for the reconstruction of bilateral tibial fractures in a patient who presented with bone loss and infection after a motorcycle road injury. A 70-year-old man presented open fractures of his both tibiae (proximal involvement on the right side and diaphyseal on the left side). After initial treatment with multiple débridements and the placement of bilateral external fixators, he had bone loss to both tibiae and had developed infections of both legs with multiple organisms identified (Stenotrophomonas maltophilia, Enterobacter cloacae, and Pseudomonas aeruginosa). We used a porous alumina ceramic, designed according to the defects to fill. This ceramic was loaded with antibiotics (gentamicin and vancomycin). The goal was to obtain locally high concentrations of antibiotics to eradicate bacteria that could have remain in the surgical wound. Ceramic parts were placed 4 months after the trauma. Local antibiotic concentrations largely exceeded the pharmacological parameters for antibiotics efficacy. External fixators were removed 3 months after implantation. After a follow-up of more than 1 year, there is no relapse of infection, and the patient resumed walking while ceramic parts were left in place and that bone started colonizing ceramic parts. This ceramic that combines strength and the possibility of antibiotic loading allows thinking of new ways to treat infected fractures with bone loss. Indeed, its mechanical strength provides primary stability, and antibiotics make it possible to secure implantation in an infected area.

Can brushing with regular and whitening dentifrices influence changes in color and micromorphologic surfaces of ceramic brackets subjected to coffee staining?

The aim of the present study was to evaluate the influence of brushing with regular or whitening dentifrices on the change in color and micromorphologic surface of ceramic orthodontic brackets subjected to coffee staining. Fifty ceramic brackets were subjected to cycles of coffee staining followed by brushing according to the following groups (n = 10): C, control (no brushing); DW, brushing with distilled water; CT, brushing with Colgate Total 12 Clean Mint (regular toothpaste); COW, brushing with Colgate Optic White (containing 1% hydrogen peroxide); and CUWA, brushing with Close-Up White Attraction (containing blue covarine). The color of the brackets was assessed using the Commission Internationale de l'Eclairage (CIE) L*a*b* system at 5 different timepoints: prior to staining (baseline) and after 1, 7, 14, and 21 days of staining and brushing cycles. The surface micromorphology of the brackets was assessed at the baseline timepoint and after 21 days. Kruskal-Wallis, Dunn, Friedman, and Nemenyi tests were applied (α = 0.05) for the statistical analysis. The C group demonstrated a significant reduction in L* and a significant increase in a* and b* values over time. For the DW group, the L* value was reduced but was higher than in the C group, and there were also significant increases in a* and b* from baseline values. A significant increase in the a* and b* values was observed in all groups (P < 0.05). Total color change (∆E*) increased over the period of evaluation for all whitening groups, although only the CT group presented significantly lower ∆E* than the other dentifrices. At the end of the test period, only the COW group exhibited a surface with higher porosity. None of the dentifrices prevented the brackets from staining, but they did reduce the magnitude of color change caused by coffee. The most significant difference was found in the CT group. Micromorphologic surface changes were observed when COW was employed.

In Vitro Performance of Different Universal Adhesive Systems on Several CAD/CAM Restorative Materials After Thermal Aging

OBJECTIVE

To evaluate the microshear bond strength (mSBS) of 10 universal adhesive systems applied on five different CAD/CAM restorative materials, immediately and after thermal aging.

METHODS AND MATERIALS

Five CAD/CAM materials were selected: 1) feldspathic glass ceramic (FeCe); 2) pre-polymerized reinforced resin composite (ReRC); 3) leucite-reinforced glass ceramic (LeGC); 4) lithium disilicate (LiDi); and 5) yttrium-stabilized zirconium dioxide (ZiDi). For each material, 15 blocks were cut into four rectangular sections (6 × 6 × 6 mm; n=60 per group) and processed as recommended by the respective manufacturer. For each indirect material, the following adhesive systems were applied according to the respective manufacturer's instructions: 1) AdheSE Universal [ADU]; 2) All-Bond Universal [ABU]; 3) Ambar Universal [AMB]; 4) Clearfil Universal Bond [CFU]; 5) Futurabond U [FBU]; 6) One Coat 7 Universal [OCU]; 7) Peak Universal Bond [PUB]; 8) Prime&Bond Elect [PBE]; 9) Scotchbond Universal Adhesive [SBU]; 10) Xeno Select [XEN, negative control]. After the application of the adhesive system, cylinder-shaped transparent matrices were filled with a dual-curing resin cement (NX3) and light cured. Specimens were tested in shear mode at 1.0 mm/ min (mSBS), after 24 hours and 10,000 thermal cycles (TC). All data were submitted to statistical analysis (α=0.05).

RESULTS

For FeCe, there was no significant decrease in mean mSBS for AMB, FBU, and SBU after TC when compared at 24 hours. For ReRC, AMB and SBU showed higher mean mSBS when compared to CFU and XEN, after 24 hours and TC. For LiDi, FBU and OCU showed higher mean mSBS when compared to CFU and XEN, after 24 hours and TC. For LeGC, AMB and PUB showed higher mean mSBS when compared to XEN, after 24 hours and TC. For ZiDi, OCU and SBU showed higher mean mSBS when compared to XEN, after 24 hours and TC. In addition, PBE and XEN showed the lowest mean mSBS after TC with higher percentage of bond strength reduction.

CONCLUSIONS

The mean mSBS among the different universal adhesives varied widely for each CAD/ CAM material used. In addition, most universal adhesives underwent a statistically significant bond strength reduction after TC.

3D-printed, bioactive ceramic scaffold with rhBMP-2 in treating critical femoral bone defects in rabbits using the induced membrane technique

Although autogenous bone grafts are an optimal filling material for the induced membrane technique, limited availability and complications at the harvest site have created a need for alternative graft materials. We aimed to investigate the effect of an rhBMP-2-coated, 3D-printed, macro/microporous CaO-SiO2 -P2 O5 -B2 O3 bioactive ceramic scaffold in the treatment of critical femoral bone defects in rabbits using the induced membrane technique. A 15-mm segmental bone defect was made in the metadiaphyseal area of the distal femur of 14 rabbits. The defect was filled with polymethylmethacrylate cement and stabilized with a 2.0 mm locking plate. After the membrane matured for 4 weeks, the scaffold was implanted in two randomized groups: Group A (3D-printed bioceramic scaffold) and Group B (3D-printed, bioceramic scaffold with rhBMP-2). Eight weeks after implantation, the radiographic assessment showed that the healing rate of the defect was significantly higher in Group B (7/7, 100%) than in Group A (2/7, 29%). The mean volume of new bone formation around and inside the scaffold doubled in Group B compared to that in Group A. The mean static and dynamic stiffness were significantly higher in Group B. Histological examination revealed newly formed bone in both groups. Extensive cortical bone formation along the scaffold was found in Group B. Successful bone reconstruction in critical-sized bone defects could be obtained using rhBMP-2-coated, 3D-printed, macro/microporous bioactive ceramic scaffolds. This grafting material demonstrated potential as an alternative graft material in the induced membrane technique for reconstructing critical-sized bone defects.

Assessment of novel surgical procedures using decellularised muscle and bioactive ceramic: a histological analysis

Tissue regeneration and neovascularisation in cases of major bone loss is a challenge in maxillofacial surgery. The hypothesis of the present study is that the addition of resorbable bioactive ceramic Silica Calcium Phosphate Cement (SCPC) to Declluraized Muscle Scaffold (DSM) can expedite bone formation and maturation. Two surgical defect models were created in 18 nude transgenic mice. Group 1(n = 6), with a 2-mm decortication calvarial defect, was treated with a DSM/SCPC sheet over the corticated bone as an onlay then seeded with human Mesenchymal Stromal Cells hMSC in situ. In Group 2 (n = 6), a critical size (4 mm) calvarial defect was made and grafted with DSM/SCPC/in situ human bone marrow stromal cells (hMSCs). The control groups included Group 3 (n = 3) animals, with a 2-mm decortication defect treated with an onlay DSM sheet, and Group 4 (n = 3) animals, treated with critical size defect grafted with plain DSM. After 8 weeks, bone regeneration in various groups was evaluated using histology, immunohistochemistry and histomorphometry. New bone formation and maturation was superior in groups treated with DSM/SCPC/hMSC. The DMS/SCPC scaffold has the ability to augment and induce bone regeneration and neovascularisation in cases of major bone resorption and critical size defects.

Bacteriological Evaluation of Gingival Crevicular Fluid in Teeth Restored Using Fixed Dental Prostheses: An In Vivo Study

The present in vivo study determined the microbiological counts of the gingival crevicular fluid (GCF) among patients with fixed dental prostheses fabricated using three different techniques. A total of 129 subjects were divided into three study groups: first, cobalt-chrome-based, metal-ceramic prostheses fabricated by the conventional method (MC, n = 35); the second group consisted of cobalt-chrome-based, metal-ceramic prostheses fabricated by the computer-aided design and computer-aided manufacturing (CAD/CAM) technique (CC-MC, n = 35); the third group comprised zirconia-based ceramic prostheses fabricated using the CAD/CAM technique (CC-Zr, n = 35). The control consisted of 24 patients using prostheses fabricated with either MC, CC-MC, or CC-Zr. The GCF was obtained from the subjects before treatment, and 6 and 12 months after the prosthetic treatment. Bacteriological and bacterioscopic analysis of the GCF was performed to analyze the patients’ GCF. The data were analyzed using SPSS V20 (IBM Company, Chicago, IL, USA). The number of microorganisms of the gingival crevicular fluid in all groups at 12 months of prosthetic treatment reduced dramatically compared with the data obtained before prosthetic treatment. Inflammatory processes in the periodontium occurred slowly in the case of zirconium oxide-based ceramic constructions due to their biocompatibility with the mucous membranes and tissues of the oral cavity as well as a reduced risk of dental biofilm formation. This should be considered by dentists and prosthodontists when choosing restoration materials for subjects with periodontal pathology.

Effect of milling, fitting adjustments, and hydrofluoric acid etching on the strength and roughness of CAD-CAM glass-ceramics: A systematic review and meta-analysis

STATEMENT OF PROBLEM

Whether procedures performed before the cementation of computer-aided design and computer-aided manufacturing (CAD-CAM) glass-ceramic restorations, including milling, fitting adjustment, and hydrofluoric acid etching introduce defects on the ceramic surface that affect the mechanical and surface properties is unclear.

PURPOSE

A systematic review and meta-analysis were conducted to assess the effect of milling, fitting adjustments, and hydrofluoric acid etching (HF) on the flexural strength and roughness (Ra) of CAD-CAM glass-ceramics.

MATERIAL AND METHODS

Literature searches were performed up to June 2020 in the PubMed/MEDLINE, Web of Science, and Scopus databases, with no publication year or language limits. The focused question was "Do milling, fitting adjustments, and hydrofluoric acid etching affect the flexural strength and roughness of CAD-CAM glass-ceramics?" For the meta-analysis, flexural strength and Ra data on milling, fitting adjustment, and HF etching versus control (polishing) were analyzed globally. A subgroup analysis assessed the effect of etching parameters (HF concentration and time) on the flexural strength and roughness of CAD-CAM glass-ceramics with different microstructures. Comparisons were performed with random-effect models at 5% significance.

RESULTS

Fourteen studies from 2764 potentially relevant records were included in the qualitative syntheses, and 12 in the meta-analysis. Milling and fitting adjustments increased roughness and reduced the flexural strength of CAD-CAM glass-ceramics. The effect of HF etching was dependent on the glass-ceramic microstructure, HF concentration, and etching time. For feldspathic- and leucite-reinforced ceramics, HF 5% applied for between 30 and 120 seconds increased roughness without affecting flexural strength. For lithium disilicate glass-ceramics, HF concentrations greater than 4.9% used for 20 seconds or more reduced the strength without affecting the surface roughness.

CONCLUSIONS

The flexural strength of CAD-CAM glass-ceramic is reduced by grinding procedures such as milling and fitting adjustment. Ceramic microstructure, HF concentration, and etching time determined the effect of hydrofluoric acid etching on the flexural strength and surface roughness of glass-ceramic materials.

Challenges in Bone Tissue Regeneration: Stem Cell Therapy, Biofunctionality and Antimicrobial Properties of Novel Materials and Its Evolution

An aging population leads to increasing demand for sustained quality of life with the aid of novel implants. Patients expect fast healing and few complications after surgery. Increased biofunctionality and antimicrobial behavior of implants, in combination with supportive stem cell therapy, can meet these expectations. Recent research in the field of bone implants and the implementation of autologous mesenchymal stem cells in the treatment of bone defects is outlined and evaluated in this review. The article highlights several advantages, limitations and advances for metal-, ceramic- and polymer-based implants and discusses the future need for high-throughput screening systems used in the evaluation of novel developed materials and stem cell therapies. Automated cell culture systems, microarray assays or microfluidic devices are required to efficiently analyze the increasing number of new materials and stem cell-assisted therapies. Approaches described in the literature to improve biocompatibility, biofunctionality and stem cell differentiation efficiencies of implants range from the design of drug-laden nanoparticles to chemical modification and the selection of materials that mimic the natural tissue. Combining suitable implants with mesenchymal stem cell treatment promises to shorten healing time and increase treatment success. Most research studies focus on creating antibacterial materials or modifying implants with antibacterial coatings in order to address the increasing number of complications after surgeries that are mostly caused by bacterial infections. Moreover, treatment of multiresistant pathogens will pose even bigger challenges in hospitals in the future, according to the World Health Organization (WHO). These antibacterial materials will help to reduce infections after surgery and the number of antibiotic treatments that contribute to the emergence of new multiresistant pathogens, whilst the antibacterial implants will help reduce the amount of antibiotics used in clinical treatment.

Tolerance and safety of 45S5 bioactive glass used in obliteration procedures during middle ear surgery: Preliminary results

OBJECTIVE

Otologists face many disadvantages after extensive mastoid drilling and canal wall down technique in cholesteatoma surgery. Mastoid and epitympanic cavity obliterations or reconstructions after canal wall down procedure using bioactive glass seem to be an interesting solution to overcome some of these disadvantages. Bioactive glass offers many benefits including the availability when there are no sufficient autologous materials for obliteration, its antibacterial activity in chronic infected ear and decreasing the recidivism of cholesteatoma. The objective of this study is to evaluate the tolerance and safety of 45S5 bioactive glass as a filing bone-synthetic material by clinical, audiological and radiological examinations.

METHODOLOGY

A retrospective study of 42 patients who had undergone obliteration of mastoid or/and epitympanic cavity with 45S5 bioactive glass between, November 2017 to January 2019. Data from clinical follow-ups, audiological assessment, CT-scan and MRI were analyzed.

RESULT

The patients' mean age was 49.8 years old. Microscopic examinations showed dry well-healed tympanic membranes and external auditory canals for 95.2% of the patients after 1 year. Inner ear injuries after obliteration were not observed by comparing pre and post-operative bone conduction audiometry (p value 0.457). No facial palsy was reported post-operatively. One-year postoperative radiological assessments did not reveal any silent implantation of cholesteatoma or residual disease.

CONCLUSION

Mastoid and epitympanic obliterations with 45S5 bioactive glass seem to be a tolerable and safe option in cholesteatoma surgery with favorable outcomes similar to other member of bioactive glass especially the S53P4.

Mixed ceramic combinations in primary total hip arthroplasty achieved reassuring mid-to-longterm outcomes

INTRODUCTION

Ceramic-on-ceramic couplings demonstrated to be reliable bearings in primary total hip arthroplasty (THA), with long-term remarkable results. Like-on-like configurations were widely described. On the contrary, mixed material combinations from the same manufacturer, Delta-on-Forte or Forte-on-Delta, were poorly studied. In particular, it is unknown whether mixed ceramic combinations are more at risk of ceramic fractures. Thus, a registry study was conducted to investigate the long-term survival rates and reasons for revision of mixed ceramic combinations. A comparison with Delta-on-Delta couplings was also performed.

MATERIALS AND METHODS

The regional arthroplasty registry RIPO was enquired about three cohorts of ceramic bearings (head-on-liner: Delta-on-Forte, Forte-on-Delta, Delta-on-Delta). Demographics, survival rates and reasons for revision were evaluated and compared.

RESULTS

In total, 346 (1.5%) implants had a Delta-on-Forte coupling (mean follow-up: 6.4 years). In total, 1163 (5%) THAs had a Forte-on-Delta articulation (mean follow-up: 8.2 years). Delta-on-Delta surfaces were implanted in 21,874 (93.5%) hips (mean follow-up: 3.9 years). Mixed material combinations were implanted between 2003 and 2007. The survival rates of the three cohorts were similar and were higher than 95% at 10 years. In Forte-on-Delta group, four liners failed (0.3% of the implants), whereas ceramic fractures occurred in 15 cases (0.1%) in Delta-on-Delta couplings (3 heads and 12 liners). Considering ceramic fracture as endpoint, there was no significant difference between the three survival rates.

CONCLUSIONS

Mixed ceramic bearing configurations from the same manufacturer in primary THA showed mid-to-longterm dependable outcomes, not inferior to the most recent like-on-like ceramic bearings. No additional risks of ceramic fractures were evident. Thus, closer follow-ups are not required.

Fracture Resistance of New Metal-Free Materials Used for CAD-CAM Fabrication of Partial Posterior Restorations

Background and Objectives: To evaluate in vitro the fracture resistance and fracture type of computer-aided design and computer-aided manufacturing (CAD-CAM) materials. Materials and Methods: Discs were fabricated (10 × 1.5 mm) from four test groups (N = 80; N = 20 per group): lithium disilicate (LDS) group (control group): IPS e.max CAD^®; zirconium-reinforced lithium silicate (ZRLS) group: VITA SUPRINITY^®; polymer-infiltrated ceramic networks (PICN) group: VITA ENAMIC^®; resin nanoceramics (RNC) group: LAVA™ ULTIMATE. Each disc was cemented (following the manufacturers’ instructions) onto previously prepared molar dentin. Samples underwent until fracture using a Shimadzu^® test machine. The stress suffered by each material was calculated with the Hertzian model, and its behavior was analyzed using the Weibull modulus. Data were analyzed with ANOVA parametric statistical tests. Results: The LDS group obtained higher fracture resistance (4588.6 MPa), followed by the ZRLS group (4476.3 MPa) and PICN group (4014.2 MPa) without statistically significant differences (p < 0.05). Hybrid materials presented lower strength than ceramic materials, the RNC group obtaining the lowest values (3110 MPa) with significant difference (p < 0.001). Groups PICN and RNC showed greater occlusal wear on the restoration surface prior to star-shaped fracture on the surface, while other materials presented radial fracture patterns. Conclusion: The strength of CAD-CAM materials depended on their composition, lithium disilicate being stronger than hybrid materials.

Bioactive Pore-Forming Bone Adhesives Facilitating Cell Ingrowth for Fracture Healing

The effectiveness of commercial bone adhesives is known to be hampered by the weak efficacy of cell ingrowth. The strategy of macropore-forming, especially bioactive macropores, holds considerable promise to circumvent this problem, thereby promoting fracture healing. Herein, a class of bioactive glass-involved macropore-embedded bone adhesives is developed, which is capable of facilitating the migration of bone-derived mesenchymal stromal cells into the adhesive layer and differentiation into osteocytes. The integration of bioactive glass-particle-encapsulated porogens in the bone adhesives is key to this approach. A robust instant bonding on the bone adhesive and a high efficiency of bone regeneration on a mouse skull are observed, both of which are vital for clinical applications and personalized surgical procedures. This work represents a general strategy to design biomaterials with high cell-ingrowth efficacy.

Bioglass/PLGA associated to photobiomodulation: effects on the healing process in an experimental model of calvarial bone defect

Bioactive glasses (BG) are known for their ability to bond to bone tissue. However, in critical situations, even the osteogenic properties of BG may be not enough to induce bone consolidation. Thus, the enrichment of BG with polymers such as Poly (D, L-lactic-co-glycolic) acid (PLGA) and associated to photobiomodulation (PBM) may be a promising strategy to promote bone tissue healing. The aim of the present study was to investigate the in vivo performance of PLGA supplemented BG, associated to PBM therapy, using an experimental model of cranial bone defect in rats. Rats were distributed in 4 different groups (Bioglass, Bioglass/PBM, Bioglas/PLGA and BG/PLGA/PBM). After the surgical procedure to induce cranial bone defects, the pre-set samples were implanted and PBM treatment (low-level laser therapy) started (808 nm, 100 mW, 30 J/cm²). After 2 and 6 weeks, animals were euthanized, and the samples were retrieved for the histopathological, histomorphometric, picrosirius red staining and immunohistochemistry analysis. At 2 weeks post-surgery, it was observed granulation tissue and areas of newly formed bone in all experimental groups. At 6 weeks post-surgery, BG/PLGA (with or without PBM) more mature tissue around the biomaterial particles. Furthermore, there was a higher deposition of collagen for BG/PLGA in comparison with BG/PLGA/PBM, at second time-point. Histomorphometric analysis demonstrated higher values of BM.V/TV for BG compared to BG/PLGA (2 weeks post-surgery) and N.Ob/T.Ar for BG/PLGA compared to BG and BG/PBM (6 weeks post-surgery). This current study concluded that the use of BG/PLGA composites, associated or not to PBM, is a promising strategy for bone tissue engineering.

Supplementation with 45S5 Bioactive Glass Reduces In Vivo Resorption of the β-Tricalcium-Phosphate-Based Bone Substitute Material Vitoss

Compared to other materials such as 45S5 bioactive glass (BG), β-tricalcium phosphate (β-TCP)-based bone substitutes such as Vitoss show limited material-driven stimulation of osteogenesis and/or angiogenesis. The unfavorable degradation kinetics of β-TCP-based bone substitutes may result in an imbalance between resorption and osseous regeneration. Composite materials like Vitoss BA (Vitoss supplemented with 20 wt % 45S5-BG particles) might help to overcome these limitations. However, the influence of BG particles in Vitoss BA compared to unsupplemented Vitoss on osteogenesis, resorption behavior, and angiogenesis is not yet described. In this study, Vitoss and Vitoss BA scaffolds were seeded with human mesenchymal stromal cells before subcutaneous implantation in immunodeficient mice for 10 weeks. Scaffold resorption was monitored by micro-computed tomography, while osteoid formation and vascularization were assessed by histomorphometry and gene expression analysis. Whilst slightly more osteoid and improved angiogenesis were found in Vitoss BA, maturation of the osteoid was more advanced in Vitoss scaffolds. The volume of Vitoss implants decreased significantly, combined with a significantly increased presence of resorbing cells, whilst the volume remained stable in Vitoss BA scaffolds. Future studies should evaluate the interaction of 45S5-BG with resorbing cells and bone precursor cells in greater detail to improve the understanding and application of β-TCP/45S5-BG composite bone substitute materials.

Current Stage of Marine Ceramic Grafts for 3D Bone Tissue Regeneration

Bioceramic scaffolds are crucial in tissue engineering for bone regeneration. They usually provide hierarchical porosity, bioactivity, and mechanical support supplying osteoconductive properties and allowing for 3D cell culture. In the case of age-related diseases such as osteoarthritis and osteoporosis, or other bone alterations as alveolar bone resorption or spinal fractures, functional tissue recovery usually requires the use of grafts. These bone grafts or bone void fillers are usually based on porous calcium phosphate grains which, once disposed into the bone defect, act as scaffolds by incorporating, to their own porosity, the intergranular one. Despite their routine use in traumatology and dental applications, specific graft requirements such as osteoinductivity or balanced dissolution rate are still not completely fulfilled. Marine origin bioceramics research opens the possibility to find new sources of bone grafts given the wide diversity of marine materials still largely unexplored. The interest in this field has also been urged by the limitations of synthetic or mammalian-derived grafts already in use and broadly investigated. The present review covers the current stage of major marine origin bioceramic grafts for bone tissue regeneration and their promising properties. Both products already available on the market and those in preclinical phases are included. To understand their clear contribution to the field, the main clinical requirements and the current available biological-derived ceramic grafts with their advantages and limitations have been collected.

A traditional hip implant is as effective as newer types for people over 65

The studyFawsitt C, Thom H, Hunt L. Choice of prosthetic implant combinations in total hip replacement: cost-effectiveness analysis using UK and Swedish hip joint registries data. Value Health 2019;22:303-12.This study was funded by the NIHR Research for Patient Benefit Programme (project number PB-PG-0613-31032).To read the full NIHR Signal, go to https://discover.dc.nihr.ac.uk/content/signal-000771/a-traditional-hip-implant-is-as-effective-as-more-expensive-newer-types-for-older-people.

Clinical and radiographic evaluation of bioactive glass in posterior cervical and lumbar spinal fusion

INTRODUCTION

Spinal surgery of degenerative painful segments is a valuable treatment option in the management of chronic cervical and low back pain. The surgery consists in stabilizing and fusing painful vertebral segment(s). The objective of the study was to report our experience with 45S5 bioactive glass (BAG) to obtain inter-vertebral fusion in the context of posterior spine surgery.

MATERIAL AND METHOD

In this retrospective study, 30 patients with a wide range of degenerative and traumatic conditions of the cervical or lumbar spine underwent spinal fusion utilizing a synthetic bone graft substitute of BAG (GlassBone™, Noraker, Lyon-Villeurbanne, France). The pain was evaluated by VAS score, and graft consolidation was assessed on according radiographic images at 1-year post-op.

RESULTS

All patients underwent posterior spinal fusion either in the cervical or the thoraco-lumbar spine. Multi-level fusions represented the majority of the cohort (43% of patients with more than seven levels treated). Radiographic imaging demonstrated excellent fusion rates (93%) at final follow-up, equivalent to the outcomes reported in the literature for autogenous bone, with excellent bone bridging and no spinal implant loosening. Only two cases of non-union were encountered. Additionally, 90% of the patients demonstrated recovery at 1 year after surgery with a pain reduction of 60%.

CONCLUSION

The results of this retrospective study suggest that the 45S5 BAG may be an interesting alternative option to autologous graft, in terms of safety and bone fusion efficiency.

LEVEL OF EVIDENCE

IV Retrospective study.

Epidermal growth factor enhances spinal fusion: Posterolateral lumbar fusion model on rats

Objective

The aim of this study was to investigate the effects of human recombinant epidermal growth factor (EGF) on posterolateral lumbar fusion in a rat model.

Methods

36 male Sprague Dawley rats underwent posterolateral fusion at L4-5 level. They were randomly assigned to 3 groups: 1- Sham control group where no local augmentation was made, 2- Local Hydoxyapatite β-tricalcium phosphate (HA/β-TCP) augmentation group and 3- Local HA/β-TCP + EGF augmentation group. Rats were euthanized at 8 weeks post-surgery. 6 rats from each group were selected for manual palpation examination, micro-computed tomography analysis and histologic analysis; and the rest was used for biomechanical analysis.

Results

Based on manual palpation, there was no fusion in the sham control group. Fusion rate was 33.3% in the HA/β-TCP group and 66.7% in the HA/β-TCP + EGF group (p = 0.085). Micro-CT results revealed that new bone formation was higher in the HA/β-TCP + EGF group (BV/TV: 40% vs. 65%) (p = 0.004). Histologically newly formed bone tissue was more pronounced in the EGF group and compacted and bridging bone spicules were observed. The median maximum bending moment values were 0.51 Nmm (0.42–0.59), 0.73 Nmm (0.49–0.88) and 0.91 Nmm (0.66–1.03) in the sham control, HA/β-TCP and HA/β-TCP + EGF groups, respectively (p = 0.013). The median stiffness values were 1.69 N/mm (1.12–2.18), 1.68 N/mm (1.13–2.74) and 3.10 N/mm (1.66–4.40) as in the previous order (p = 0.087).

Conclusion

This study demonstrates that EGF enhances posterolateral lumbar fusion in the rat model. EGF in combination with ceramic grafts increased the fusion rates. Our findings may provide insights to further studies, investigating EGF's clinical usage as an alternative fusion enhancer.

Polish retention of ceramic-polymer CAD/CAM materials

New ceramic-polymer millable materials that may be less resistant to the abrasive effects of toothbrushing than glass-ceramic materials have been introduced recently. The purpose of this study was to evaluate the polish retention of ceramic-polymer materials after mechanical toothbrush abrasion. Four ceramic-polymer materials (Enamic, Lava Ultimate, CeraSmart, and Block HC) were compared to a lithium disilicate glass-ceramic material (IPS e.max CAD). After 10 specimens of each material were polished, baseline area surface roughness (Sa) measurements were made. Specimens were then placed in a toothbrushing machine for 60,000 strokes, simulating 8 years of brushing. Surface roughness measurements were repeated after 30,000 and 60,000 brush strokes. At the end of the brushing, IPS e.max CAD and Enamic had the lowest mean Sa values (0.50 [SD 0.17] and 0.55 [0.13] µm², respectively), while Block HC had the greatest (1.10 [0.10] µm²). Lava Ultimate and CeraSmart demonstrated intermediate Sa values (0.81 [0.14] and 0.72 [0.11] µm², respectively). Only IPS e.max CAD had no statistically significant increase in surface roughness after toothbrushing.

Bioactive Injectable Hydrogels Containing Desferrioxamine and Bioglass for Diabetic Wound Healing

Diabetic wound is hard to heal mainly because of the difficulty in vascularization in the wound area. Accumulating results have shown that desferrioxamine (DFO) can promote secretion of hypoxia inducible factor-1 (HIF-1α), thereby upregulating the expression of angiogenic growth factors and facilitating revascularization. Our preliminary study has demonstrated that Si ions in bioglass (BG) can upregulate vascular endothelial growth factor (VEGF) expression, thus promoting revascularization. It is hypothesized that the combined use of BG and DFO may have a synergistic effect in promoting VEGF expression and revascularization. To prove this, we first determined DFO concentration range that had no apparent cytotoxicity on human umbilical vein endothelial cells (HUVECs). Then, the optimal concentration of DFO promoting tube formation of HUVECs was determined by cell migration and tube formation assays. In addition, we demonstrated that combination use of BG and DFO improved the migration and tube formation of HUVECs as compared with the use of either BG or DFO alone as BG and DFO could synergistically upregulate VEGF expression. Furthermore, a sodium alginate hydrogel containing both BG and DFO was developed, and this hydrogel better facilitated diabetic skin wound healing than the use of either BG or DFO alone as BG and DFO in the hydrogels worked synergistically in promoting HIF-1α and VEGF expression and subsequently vascularization in the wound sites. Therefore, in this study, the synergistic effect in promoting revascularization between BG and DFO was first demonstrated and an injectable hydrogel simultaneously containing BG and DFO was developed for enhancing repair of diabetic chronic skin defects by taking advantages of the synergistic effects of BG and DFO in promoting revascularization. The study opens up a new prospect for the development of skin repair-promoting biomaterials.

Marginal Adaptation and Fracture Resistance of Lithium Disilicate Laminate Veneers on Teeth with Different Preparation Depths

The purpose of this study was to evaluate the marginal adaptation and fracture load of ceramic laminate veneers on teeth with different preparation depths. A total of 75 extracted intact human maxillary central incisors were prepared with three different preparation depths (P) and assigned to the following five groups (n = 15): P1 (0.3-mm depth of preparation; preparation entirely in enamel); P2 (0.5-mm depth of preparation; preparation in enamel and dentin complex); P3 (1-mm depth of preparation; preparation entirely in dentin); P4 (no preparation, only surface roughening); and P5 (unrestored, intact teeth as control). A total of 60 lithium disilicate laminate veneers were fabricated. The marginal adaptation of the veneers was evaluated by light microscope and scanning electron microscope after cementation with resin cement. Finally, the veneers were loaded until fracture at a 90-degree angle to the lingual surface of the tooth. Statistical analyses were performed using analysis of variance and Tukey multiple range test. There was a significant difference between the marginal gap value of the distocervical measurement points of P1 and P2 and the distal measurement points of P3 and P4 (P = .33 and P = .017, respectively). The highest fracture resistance values were observed in the P5 group (mean: 389.55 ± 22 N) and the P2 group (mean: 322.86 ± 79.38 N), and the lowest values were observed in the P3 group (mean: 219.21 ± 60.74 N). The marginal adaptation of the laminate veneer restorations was not related to the depth of preparation. Mean fracture resistance of laminate veneers with 0.5-mm preparation depth was greater than that of the 0.3-mm and 1-mm preparation depth laminate veneers and those with no preparation.

Effect of Different Computer-aided Design/Computer-aided Manufacturing (CAD/CAM) Materials and Thicknesses on the Fracture Resistance of Occlusal Veneers

The aim was to evaluate, in vitro, the influence of different computer-aided design/computer-aided manufacturing (CAD/CAM) materials (IPS e.max CAD, Vita Enamic, and Lava Ultimate) and thicknesses (0.6 mm and 1.5 mm) on the fracture resistance of occlusal veneers. Sixty human third molars were prepared to simulate advanced erosion of the occlusal surface, and the teeth were randomly divided into six experimental groups (n=10) according to the material and thickness used to build the veneers. Ten sound teeth formed the control group. The veneers were adhesively luted and submitted to mechanical cyclic loading (1 million cycles at 200-N load). The fracture resistance test was performed in a universal testing machine. The failures were classified as "reparable" and "irreparable." According to two-way analysis of variance and the Tukey test, the interaction (material × thickness) was significant ( p=0.013). The highest fracture resistance was obtained for IPS e.max CAD at a 1.5-mm thickness (4995 N) and was significantly higher compared to the other experimental groups ( p<0.05). The lowest fracture resistance was obtained for Vita Enamic at 0.6 mm (2973 N), although this resistance was not significantly different from those for IPS e.max CAD at 0.6 mm (3067 N), Lava Ultimate at 0.6 mm (3384 N), Vita Enamic at 1.5 mm (3540 N), and Lava Ultimate at 1.5 mm (3584 N) ( p>0.05). The experimental groups did not differ significantly from the sound teeth (3991 N) ( p>0.05). The failures were predominantly repairable. The occlusal veneers of IPS e.max CAD, Vita Enamic, and Lava Ultimate, with thicknesses of 0.6 mm and 1.5 mm, obtained fracture resistances similar to those associated with sound teeth.