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1.
Dent Mater ; 2024 Jun 29.
Artículo en Inglés | MEDLINE | ID: mdl-38945742

RESUMEN

OBJECTIVES: To assess the effects of different aging protocols on chemical, physical, and mechanical properties of an experimental ATZ composite compared to a zirconia. METHODS: Disc-shaped specimens were obtained through uniaxial pressing of commercial powders (Tosoh), ATZ comprised of 80%ZrO2/20%Al2O3 (TZ-3YS20AB) and 3Y-TZP (3Y-SBE). The specimens of each material were divided into different groups according to the aging protocol: immediate, autoclave aging and hydrothermal reactor aging. The aging protocols were performed at 134 ºC for 20 h at 2.2 bar. Crystalline evaluations were performed using X-Ray Diffraction. The nanoindentation tests measured the elastic modulus (Em) and hardness (H). Biaxial flexural strength was performed, and Weibull statistics were used to determine the characteristic strength and Weibull modulus. The probability of survival was also determined. The Em and H data were analyzed by one-way ANOVA and Tukey test. RESULTS: Diffractograms revealed the presence of monoclinic phase in both materials after aging. The hydrothermal reactor decreased the Em for ATZ compared to its immediate condition; and the H for both ATZ and 3Y-TZP regarding their immediate and autoclave aging conditions, respectively. The aging protocols significantly increased the characteristic strength for ATZ, while decreased for 3Y-TZP. No difference regarding Weibull modulus was observed, except for 3Y-TZP aged in reactor. For missions of up to 500 MPa, both materials presented a high probability of survival (>99 %) irrespective of aging condition. SIGNIFICANCE: The synthesized ATZ composite exhibited greater physical and microstructural stability compared to 3Y-TZP, supporting potential application of the experimental material for long-span reconstructive applications.

2.
Int J Mol Sci ; 25(11)2024 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-38892291

RESUMEN

Bone regeneration remains a significant clinical challenge, often necessitating surgical approaches when healing bone defects and fracture nonunions. Within this context, the modulation of adenosine signaling pathways has emerged as a promising therapeutic option, encouraging osteoblast activation and tempering osteoclast differentiation. A literature review of the PubMed database with relevant keywords was conducted. The search criteria involved in vitro or in vivo models, with clear methodological descriptions. Only studies that included the use of indirect adenosine agonists, looking at the effects of bone regeneration, were considered relevant according to the eligibility criteria. A total of 29 articles were identified which met the inclusion and exclusion criteria, and they were reviewed to highlight the preclinical translation of adenosine agonists. While preclinical studies demonstrate the therapeutic potential of adenosine signaling in bone regeneration, its clinical application remains unrealized, underscoring the need for further clinical trials. To date, only large, preclinical animal models using indirect adenosine agonists have been successful in stimulating bone regeneration. The adenosine receptors (A1, A2A, A2B, and A3) stimulate various pathways, inducing different cellular responses. Specifically, indirect adenosine agonists act to increase the extracellular concentration of adenosine, subsequently agonizing the respective adenosine receptors. The agonism of each receptor is dependent on its expression on the cell surface, the extracellular concentration of adenosine, and its affinity for adenosine. This comprehensive review analyzed the multitude of indirect agonists currently being studied preclinically for bone regeneration, discussing the mechanisms of each agonist, their cellular responses in vitro, and their effects on bone formation in vivo.


Asunto(s)
Regeneración Ósea , Agonistas del Receptor Purinérgico P1 , Receptores Purinérgicos P1 , Regeneración Ósea/efectos de los fármacos , Humanos , Animales , Receptores Purinérgicos P1/metabolismo , Agonistas del Receptor Purinérgico P1/farmacología , Agonistas del Receptor Purinérgico P1/uso terapéutico , Adenosina/análogos & derivados , Adenosina/farmacología , Adenosina/metabolismo , Transducción de Señal/efectos de los fármacos , Investigación Biomédica Traslacional
3.
Ann Plast Surg ; 93(1): 115-123, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38775371

RESUMEN

BACKGROUND: Velopharyngeal insufficiency (VPI) is a condition characterized by incomplete separation of the oral and nasal cavities during speech production, thereby leading to speech abnormalities and audible nasal emissions. Subsequently, this adversely impacts communication and potentially interpersonal social interactions. Autologous fat grafting (AFG) to the velopharynx, a minimally invasive technique, aims to improve oronasal separation by providing bulk and advancing the posterior pharyngeal wall toward the soft palate. Despite its potential, the relative novelty of AFG in treating VPI has resulted in reporting of inconsistent indications, varied surgical techniques, and mixed outcomes across existing literature. METHODS: This systemic review examined the evidence of AFG for VPI treatment over the past decade (2013-2023). A thorough search across five electronic databases yielded 233 studies, with 20 meeting the inclusion criteria (e.g., utilized fat injection as their selected VPI treatment, conducted study in human subjects, did not perform additional surgical procedure at time of fat injection). Selected studies encompassed patient and surgical intervention characteristics, perceptual speech assessment (PSA) scores, gap sizes, nasalance measurements, and complications. RESULTS: The majority of patients had a prior cleft palate diagnosis (78.2%), in which nasoendoscopy was the prevalent method for visualizing the velopharyngeal port defect. Fat harvesting predominantly occurred from the abdomen (64.3%), with an average injection volume of 6.3 mL across studies. PSA and subjective gap size scores were consistently higher preoperatively than postoperatively. PSA score analysis from seven studies revealed significant and sustained improvements postoperatively. Gap size score analysis from four studies demonstrated similar preoperative and postoperative differences. Complications were reported in 17 studies, yielding a 2.7% summative complication rate among 594 cases. CONCLUSIONS: Autologous fat grafting has emerged as a minimally invasive, safe, and effective treatment for mild to moderate VPI. However, challenges remain because of variability in patient selection criteria, diagnostic modalities, and outcome measurements. This review underscores the need for randomized control trials to directly compare AFG with standard-of-care surgical interventions, providing more conclusive evidence of its clinical efficacy.


Asunto(s)
Tejido Adiposo , Trasplante Autólogo , Insuficiencia Velofaríngea , Insuficiencia Velofaríngea/cirugía , Humanos , Tejido Adiposo/trasplante , Resultado del Tratamiento
4.
Artículo en Inglés | MEDLINE | ID: mdl-38727247

RESUMEN

Background: Non-perforated Polytetrafluoroethylene (PTFE) membranes are effectively utilized in guided bone regeneration (GBR) but may hinder cell migration due to limited interaction with the periosteum. This study compared bone regeneration using occlusive or perforated membranes combined with acellular collagen sponge (ACS) and recombinant human bone morphogenic protein-2 (rhBMP-2) in a canine mandibular model. Material and Methods: Male beagle dogs (n=3) received two mandibular defects each to compare ACS/rhBMP-2 with experimental (perforated group) and control (non-perforated group) membranes (n=3 defects/group). Tissue healing was assessed histomorphologically, histomorphometrically and through volumetric reconstruction using microcomputed tomography. Results: The perforated group showed increased bone formation and reduced soft tissue formation compared to the non-perforated group. For the primary outcome, histomorphometric analysis revealed significantly greater total regenerated bone in the perforated group (67.08 ± 6.86%) relative to the nonperforated group (25.18 ± 22.44%) (p = 0.036). Perforated membranes had less soft tissue infiltration (32.91 ± 6.86%) compared to non-perforated membranes (74.82 ± 22.44%) (p = 0.036). Conclusion: The increased permeability of membranes in the perforated group potentially enabled periosteal precursor cells greater accessibility to rhBMP-2. The availability may have accelerated their differentiation into mature bone-forming cells, contributing to the stimulation of new bone production, relative to the non-perforated group.

5.
J Craniofac Surg ; 2024 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-38738906

RESUMEN

This manuscript reviews the transformative impact of 3-dimensional (3D) printing technologies in the treatment and management of cleft lip and palate (CLP), highlighting its application across presurgical planning, surgical training, implantable scaffolds, and postoperative care. By integrating patient-specific data through computer-aided design and manufacturing, 3D printing offers tailored solutions that improve surgical outcomes, reduce operation times, and enhance patient care. The review synthesizes current research findings, technical advancements, and clinical applications, illustrating the potential of 3D printing to revolutionize CLP treatment. Further, it discusses the future directions of combining 3D printing with other innovative technologies like artificial intelligence, 4D printing, and in situ bioprinting for more comprehensive care strategies. This paper underscores the necessity for multidisciplinary collaboration and further research to overcome existing challenges and fully utilize the capabilities of 3D printing in CLP repair.

6.
Biomed Mater Eng ; 35(4): 365-375, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38578877

RESUMEN

BACKGROUND: ß-tricalcium phosphate (ß-TCP) has been successfully utilized as a 3D printed ceramic scaffold in the repair of non-healing bone defects; however, it requires the addition of growth factors to augment its regenerative capacity. Synthetic bone mineral (SBM) is a novel and extrudable carbonate hydroxyapatite with ionic substitutions known to facilitate bone healing. However, its efficacy as a 3D printed scaffold for hard tissue defect repair has not been explored. OBJECTIVE: To evaluate the biocompatibility and cell viability of human osteoprecursor (hOP) cells seeded on 3D printed SBM scaffolds via in vitro analysis. METHODS: SBM and ß-TCP scaffolds were fabricated via 3D printing and sintered at various temperatures. Scaffolds were then subject to qualitative cytotoxicity testing and cell proliferation experiments utilizing (hOP) cells. RESULTS: SBM scaffolds sintered at lower temperatures (600 °C and 700 °C) induced greater levels of acute cellular stress. At higher sintering temperatures (1100 °C), SBM scaffolds showed inferior cellular viability relative to ß-TCP scaffolds sintered to the same temperature (1100 °C). However, qualitative analysis suggested that ß-TCP presented no evidence of morphological change, while SBM 1100 °C showed few instances of acute cellular stress. CONCLUSION: Results demonstrate SBM may be a promising alternative to ß-TCP for potential applications in bone tissue engineering.


Asunto(s)
Fosfatos de Calcio , Proliferación Celular , Supervivencia Celular , Ensayo de Materiales , Impresión Tridimensional , Andamios del Tejido , Fosfatos de Calcio/química , Fosfatos de Calcio/farmacología , Andamios del Tejido/química , Humanos , Supervivencia Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Materiales Biocompatibles/química , Materiales Biocompatibles/farmacología , Sustitutos de Huesos/química , Sustitutos de Huesos/farmacología , Ingeniería de Tejidos/métodos , Células Cultivadas
7.
ACS Biomater Sci Eng ; 10(5): 3097-3107, 2024 05 13.
Artículo en Inglés | MEDLINE | ID: mdl-38591966

RESUMEN

To develop a peri-implantitis model in a Gottingen minipig and evaluate the effect of local application of salicylic acid poly(anhydride-ester) (SAPAE) on peri-implantitis progression in healthy, metabolic syndrome (MS), and type-2 diabetes mellitus (T2DM) subjects. Eighteen animals were allocated to three groups: (i) control, (ii) MS (diet for obesity induction), and (iii) T2DM (diet plus streptozotocin for T2DM induction). Maxillary and mandible premolars and first molar were extracted. After 3 months of healing, four implants per side were placed in both jaws of each animal. After 2 months, peri-implantitis was induced by plaque formation using silk ligatures. SAPAE polymer was mixed with mineral oil (3.75 mg/µL) and topically applied biweekly for up to 60 days to halt peri-implantitis progression. Periodontal probing was used to assess pocket depth over time, followed by histomorphologic analysis of harvested samples. The adopted protocol resulted in the onset of peri-implantitis, with healthy minipigs taking twice as long to reach the same level of probing depth relative to MS and T2DM subjects (∼3.0 mm), irrespective of jaw. In a qualitative analysis, SAPAE therapy revealed decreased levels of inflammation in the normoglycemic, MS, and T2DM groups. SAPAE application around implants significantly reduced the progression of peri-implantitis after ∼15 days of therapy, with ∼30% lower probing depth for all systemic conditions and similar rates of probing depth increase per week between the control and SAPAE groups. MS and T2DM conditions presented a faster progression of the peri-implant pocket depth. SAPAE treatment reduced peri-implantitis progression in healthy, MS, and T2DM groups.


Asunto(s)
Periimplantitis , Ácido Salicílico , Porcinos Enanos , Animales , Porcinos , Periimplantitis/tratamiento farmacológico , Periimplantitis/patología , Ácido Salicílico/administración & dosificación , Ácido Salicílico/farmacología , Ácido Salicílico/uso terapéutico , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Hiperglucemia/tratamiento farmacológico , Masculino , Diabetes Mellitus Experimental/tratamiento farmacológico , Síndrome Metabólico/tratamiento farmacológico , Síndrome Metabólico/metabolismo , Implantes Dentales
8.
Bioengineering (Basel) ; 11(4)2024 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-38671741

RESUMEN

The energy state of endosteal implants is dependent on the material, manufacturing technique, cleaning procedure, sterilization method, and surgical manipulation. An implant surface carrying a positive charge renders hydrophilic properties, thereby facilitating the absorption of vital plasma proteins crucial for osteogenic interactions. Techniques to control the surface charge involve processes like oxidation, chemical and topographical adjustments as well as the application of nonthermal plasma (NTP) treatment. NTP at atmospheric pressure and at room temperature can induce chemical and/or physical reactions that enhance wettability through surface energy changes. NTP has thus been used to modify the oxide layer of endosteal implants that interface with adjacent tissue cells and proteins. Results have indicated that if applied prior to implantation, NTP strengthens the interaction with surrounding hard tissue structures during the critical phases of early healing, thereby promoting rapid bone formation. Also, during this time period, NTP has been found to result in enhanced biomechanical fixation. As such, the application of NTP may serve as a practical and reliable method to improve healing outcomes. This review aims to provide an in-depth exploration of the parameters to be considered in the application of NTP on endosteal implants. In addition, the short- and long-term effects of NTP on osseointegration are addressed, as well as recent advances in the utilization of NTP in the treatment of periodontal disease.

9.
J Mech Behav Biomed Mater ; 154: 106533, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38598918

RESUMEN

The present work aims to develop a production method of pre-sintered zirconia-toughened-alumina (ZTA) composite blocks for machining in a computer-aided design and computer-aided manufacturing (CAD-CAM) system. The ZTA composite comprised of 80% Al2O3 and 20% ZrO2 was synthesized, uniaxially and isostatically pressed to generate machinable CAD-CAM blocks. Fourteen green-body blocks were prepared and pre-sintered at 1000 °C. After cooling and holder gluing, a stereolithography (STL) file was designed and uploaded to manufacture disk-shaped specimens projected to comply with ISO 6872:2015. Seventy specimens were produced through machining of the blocks, samples were sintered at 1600 °C and two-sided polished. Half of the samples were subjected to accelerated autoclave hydrothermal aging (20h at 134 °C and 2.2 bar). Immediate and aged samples were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Optical and mechanical properties were assessed by reflectance tests and by biaxial flexural strength test, Vickers indentation and fracture toughness, respectively. Samples produced by machining presented high density and smooth surfaces at SEM evaluation with few microstructural defects. XRD evaluation depicted characteristic peaks of alpha alumina and tetragonal zirconia and autoclave aging had no effect on the crystalline spectra of the composite. Optical and mechanical evaluations demonstrated a high masking ability for the composite and a characteristic strength of 464 MPa and Weibull modulus of 17, with no significant alterations after aging. The milled composite exhibited a hardness of 17.61 GPa and fracture toughness of 5.63 MPa m1/2, which remained unaltered after aging. The synthesis of ZTA blocks for CAD-CAM was successful and allowed for the milling of disk-shaped specimens using the grinding method of the CAD-CAM system. ZTA composite properties were unaffected by hydrothermal autoclave aging and present a promising alternative for the manufacture of infrastructures of fixed dental prostheses.


Asunto(s)
Óxido de Aluminio , Cerámica , Ensayo de Materiales , Óxido de Aluminio/química , Cerámica/química , Propiedades de Superficie , Circonio/química , Diseño Asistido por Computadora , Materiales Dentales
10.
J Orthop Res ; 2024 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-38598203

RESUMEN

Non-union during healing of bone fractures affects up to ~5% of patients worldwide. Given the success of recombinant human platelet-derived growth factor-B chain homodimer (rhPDGF-BB) in promoting angiogenesis and bone fusion in the hindfoot and ankle, rhPDGF-BB combined with bovine type I collagen/ß-TCP matrix (AIBG) could serve as a viable alternative to autografts in the treatment of non-unions. Defects (~2 mm gaps) were surgically induced in tibiae of skeletally mature New Zealand white rabbits. Animals were allocated to one of four groups-(1) negative control (empty defect, healing for 8 weeks), (2 and 3) acute treatment with AIBG (healing for 4 or 8 weeks), and (4) chronic treatment with AIBG (injection 4 weeks post defect creation and then healing for 8 weeks). Bone formation was analyzed qualitatively and semi-quantitatively through histology. Samples were imaged using dual-energy X-ray absorptiometry and computed tomography for defect visualization and volumetric reconstruction, respectively. Delayed healing or non-healing was observed in the negative control group, whereas defects treated with AIBG in an acute setting yielded bone formation as early as 4 weeks with bone growth appearing discontinuous. At 8 weeks (acute setting), substantial remodeling was observed with higher degrees of bone organization characterized by appositional bone growth. The chronic healing, experimental, group yielded bone formation and remodeling, with no indication of non-union after treatment with AIBG. Furthermore, bone growth in the chronic healing group was accompanied by an increased presence of osteons, osteonal canals, and interstitial lamellae. Qualitatively and semiquantitatively, chronic application of AI facilitated complete bridging of the induced non-union defects, while untreated defects or defects treated acutely with AIBG demonstrated a lack of complete bridging at 8 weeks.

11.
J Biomed Mater Res B Appl Biomater ; 112(4): e35402, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38520704

RESUMEN

There is an ever-evolving need of customized, anatomic-specific grafting materials for bone regeneration. More specifically, biocompatible and osteoconductive materials, that may be configured dynamically to fit and fill defects, through the application of an external stimulus. The objective of this study was to establish a basis for the development of direct inkjet writing (DIW)-based shape memory polymer-ceramic composites for bone tissue regeneration applications and to establish material behavior under thermomechanical loading. Polymer-ceramic (polylactic acid [PLA]/ß-tricalcium phosphate [ß-TCP]) colloidal gels were prepared of different w/w ratios (90/10, 80/20, 70/30, 60/40, and 50/50) through polymer dissolution in acetone (15% w/v). Cytocompatibility was analyzed through Presto Blue assays. Rheological properties of the colloidal gels were measured to determine shear-thinning capabilities. Gels were then extruded through a custom-built DIW printer. Space filling constructs of the gels were printed and subjected to thermomechanical characterization to measure shape fixity (Rf) and shape recovery (Rr) ratios through five successive shape memory cycles. The polymer-ceramic composite gels exhibited shear-thinning capabilities for extrusion through a nozzle for DIW. A significant increase in cellular viability was observed with the addition of ß-TCP particles within the polymer matrix relative to pure PLA. Shape memory effect in the printed constructs was repeatable up to 4 cycles followed by permanent deformation. While further research on scaffold macro-/micro-geometries, and engineered porosities are warranted, this proof-of-concept study suggested suitability of this polymer-ceramic material and the DIW 3D printing workflow for the production of customized, patient specific constructs for bone tissue engineering.


Asunto(s)
Fosfatos de Calcio , Poliésteres , Ingeniería de Tejidos , Humanos , Poliésteres/farmacología , Polímeros , Regeneración Ósea , Geles , Andamios del Tejido , Impresión Tridimensional
12.
J Funct Biomater ; 15(3)2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38535253

RESUMEN

Three-dimensional printing (3DP) technology has revolutionized the field of the use of bioceramics for maxillofacial and periodontal applications, offering unprecedented control over the shape, size, and structure of bioceramic implants. In addition, bioceramics have become attractive materials for these applications due to their biocompatibility, biostability, and favorable mechanical properties. However, despite their advantages, bioceramic implants are still associated with inferior biological performance issues after implantation, such as slow osseointegration, inadequate tissue response, and an increased risk of implant failure. To address these challenges, researchers have been developing strategies to improve the biological performance of 3D-printed bioceramic implants. The purpose of this review is to provide an overview of 3DP techniques and strategies for bioceramic materials designed for bone regeneration. The review also addresses the use and incorporation of active biomolecules in 3D-printed bioceramic constructs to stimulate bone regeneration. By controlling the surface roughness and chemical composition of the implant, the construct can be tailored to promote osseointegration and reduce the risk of adverse tissue reactions. Additionally, growth factors, such as bone morphogenic proteins (rhBMP-2) and pharmacologic agent (dipyridamole), can be incorporated to promote the growth of new bone tissue. Incorporating porosity into bioceramic constructs can improve bone tissue formation and the overall biological response of the implant. As such, employing surface modification, combining with other materials, and incorporating the 3DP workflow can lead to better patient healing outcomes.

13.
J Biomed Mater Res B Appl Biomater ; 112(2): e35382, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38355936

RESUMEN

This in vivo study evaluated the bone healing response around endosteal implants with varying surface topography/chemistry in a preclinical, large transitional model induced with metabolic syndrome (MS) and type-2 diabetes mellitus (T2DM). Fifteen Göttingen minipigs were randomly distributed into two groups: (i) control (normal diet, n = 5) and (ii) O/MS (cafeteria diet for obesity induction, n = 10). Following obesity induction, five minipigs from the obese/metabolic syndrome (O/MS) group were further allocated, randomly, into the third experimental group: (iii) T2DM (cafeteria diet + streptozotocin). Implants with different surface topography/chemistry: (i) dual acid-etched (DAE) and (ii) nano-hydroxyapatite coating over the DAE surface (NANO), were placed into the right ilium of the subjects and allowed to heal for 4 weeks. Histomorphometric evaluation of bone-to-implant contact (%BIC) and bone area fraction occupancy (%BAFO) within implant threads were performed using histomicrographs. Implants with NANO surface presented significantly higher %BIC (~26%) and %BAFO (~35%) relative to implants with DAE surface (%BIC = ~14% and %BAFO = ~28%, p < .025). Data as a function of systemic condition presented significantly higher %BIC (~28%) and %BAFO (~42%) in the control group compared with the metabolically compromised groups (O/MS: %BIC = 14.35% and %BAFO = 26.24%, p < .021; T2DM: %BIC = 17.91% and %BAFO = 26.12%, p < .021) with no significant difference between O/MS and T2DM (p > .05). Statistical evaluation considering both factors demonstrated significantly higher %BIC and %BAFO for the NANO surface relative to DAE implant, independent of systemic condition (p < .05). The gain increase of %BIC and %BAFO for the NANO compared with DAE was more pronounced in O/MS and T2DM subjects. Osseointegration parameters were significantly reduced in metabolically compromised subjects compared with healthy subjects. Nanostructured hydroxyapatite-coated surfaces improved osseointegration relative to DAE, regardless of systemic condition.


Asunto(s)
Implantes Dentales , Diabetes Mellitus Tipo 2 , Síndrome Metabólico , Humanos , Porcinos , Animales , Oseointegración , Porcinos Enanos , Propiedades de Superficie , Obesidad , Durapatita/farmacología , Titanio , Implantación Dental Endoósea
14.
J Biomed Mater Res B Appl Biomater ; 112(1): e35347, 2024 01.
Artículo en Inglés | MEDLINE | ID: mdl-38247237

RESUMEN

Bone tissue has the capacity to regenerate under healthy conditions, but complex cases like critically sized defects hinder natural bone regeneration, necessitating surgery, and use of a grafting material for rehabilitation. The field of bone tissue engineering (BTE) has pioneered ways to address such issues utilizing different biomaterials to create a platform for cell migration and tissue formation, leading to improved bone reconstruction. One such approach involves 3D-printed patient-specific scaffolds designed to aid in regeneration of boney defects. This study aimed to develop and characterize 3D printed scaffolds composed of type I collagen augmented with ß-tricalcium phosphate (COL/ß-TCP). A custom-built direct inkjet write (DIW) printer was used to fabricate ß-TCP, COL, and COL/ß-TCP scaffolds using synthesized colloidal gels. After chemical crosslinking, the scaffolds were lyophilized and subjected to several characterization techniques, including light microscopy, scanning electron microscopy, and x-ray diffraction to evaluate morphological and chemical properties. In vitro evaluation was performed using human osteoprogenitor cells to assess cytotoxicity and proliferative capacity of the different scaffold types. Characterization results confirmed the presence of ß-TCP in the 3D printed COL/ß-TCP scaffolds, which exhibited crystals that were attributed to ß-TCP due to the presence of calcium and phosphorus, detected through energy dispersive x-ray spectroscopy. In vitro studies showed that the COL/ß-TCP scaffolds yielded more favorable results in terms of cell viability and proliferation compared to ß-TCP and COL scaffolds. The novel COL/ß-TCP scaffold constructs hold promise for improving BTE applications and may offer a superior environment for bone regeneration compared with conventional COL and ß-TCP scaffolds.


Asunto(s)
Fosfatos de Calcio , Colágeno Tipo I , Bovinos , Animales , Humanos , Fosfatos de Calcio/farmacología , Regeneración Ósea , Microscopía Electrónica de Rastreo
15.
J Craniofac Surg ; 35(1): 261-267, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-37622526

RESUMEN

Computer-aided design/computer-aided manufacturing and 3-dimensional (3D) printing techniques have revolutionized the approach to bone tissue engineering for the repair of craniomaxillofacial skeletal defects. Ample research has been performed to gain a fundamental understanding of the optimal 3D-printed scaffold design and composition to facilitate appropriate bone formation and healing. Benchtop and preclinical, small animal model testing of 3D-printed bioactive ceramic scaffolds augmented with pharmacological/biological agents have yielded promising results given their potential combined osteogenic and osteoinductive capacity. However, other factors must be evaluated before newly developed constructs may be considered analogous alternatives to the "gold standard" autologous graft for defect repair. More specifically, the 3D-printed bioactive ceramic scaffold's long-term safety profile, biocompatibility, and resorption kinetics must be studied. The ultimate goal is to successfully regenerate bone that is comparable in volume, density, histologic composition, and mechanical strength to that of native bone. In vivo studies of these newly developed bone tissue engineering in translational animal models continue to make strides toward addressing regulatory and clinically relevant topics. These include the use of skeletally immature animal models to address the challenges posed by craniomaxillofacial defect repair in pediatric patients. This manuscript reviews the most recent preclinical animal studies seeking to assess 3D-printed ceramic scaffolds for improved repair of critical-sized craniofacial bony defects.


Asunto(s)
Ingeniería de Tejidos , Andamios del Tejido , Animales , Humanos , Niño , Ingeniería de Tejidos/métodos , Regeneración Ósea , Huesos , Osteogénesis , Impresión Tridimensional
16.
J Esthet Restor Dent ; 36(2): 381-390, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37676053

RESUMEN

PURPOSE: To evaluate the reliability and failure modes of ultrathin (0.5 mm) lithium disilicate, translucent and ultra-translucent zirconia crowns for posterior teeth restorations. MATERIALS AND METHODS: Fifty-four mandibular first molar crowns of three ceramic materials: (1) Lithium disilicate (e.max CAD, Ivoclar Vivadent), (2) 3Y-TZP (Zirconn Translucent, Vipi), and (3) 5Y-PSZ (Cercon XT, Dentsply Sirona), with 0.5 mm of thickness were milled and cemented onto composite resin abutments. Eighteen samples of each group were tested under mouth-motion step-stress accelerated life testing in a humid environment using mild, moderate, and aggressive profiles. Data was subjected to Weibull statistics. Use level curves were plotted and reliability was calculated for a given mission of 100,000 cycles at 100, 200, and 300 N. Fractographic analyses of representative samples were performed in scanning electron microscope. RESULTS: Beta (ß) values suggest that failures were dictated by material's strength for lithium disilicate and by fatigue damage accumulation for both zirconias. No significant differences were detected in Weibull modulus and characteristic strength among groups. At a given mission of 100,000 cycles at 100 N, lithium disilicate presented higher reliability (98% CB: 95-99) regarding 3Y-TZP and 5Y-PSZ groups (84% CB: 65%-93% and 79% CB: 37&-94%, respectively). At 200 N, lithium disilicate reliability (82% CB: 66%-91%) was higher than 5Y-PSZ (20% CB: 4%-44%) and not significantly different from 3Y-TZP (54% CB: 32%-72%). Furthermore, at 300 N no significant differences in reliability were detected among groups, with a notable reduction in the reliability of all materials. Fractographic analyses showed that crack initiated at the interface between the composite core and the ceramic crowns due to tensile stress generated at the intaglio surface. CONCLUSIONS: Ultrathin lithium disilicate crowns demonstrated higher reliability relative to zirconia crowns at functional loads. Lithium disilicate and zirconia crown's reliability decreased significantly for missions at higher loads and similar failure modes were observed regardless of crown material. The indication of 0.5 mm thickness crowns in high-load bearing regions must be carefully evaluated. CLINICAL SIGNIFICANCE: Ultraconservative lithium disilicate and zirconia crowns of 0.5 mm thickness may be indicated in anterior restorations and pre-molars. Their clinical indication in high-load requirement regions must be carefully evaluated.


Asunto(s)
Coronas , Porcelana Dental , Reproducibilidad de los Resultados , Ensayo de Materiales , Cerámica , Circonio , Análisis del Estrés Dental , Fracaso de la Restauración Dental , Diseño Asistido por Computadora
17.
J Mech Behav Biomed Mater ; 150: 106311, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38128470

RESUMEN

This study aimed to develop a recycling process for the remnants of milled 3Y-TZP and enhance their properties using glass infiltration. 3Y-TZP powder was gathered from the vacuum system of CAD-CAM milling equipment, calcined and sieved (x < 75 µm). One hundred twenty discs were fabricated and pre-sintered at 1000 °C/h. These specimens were then divided into four groups, categorized by glass infiltration (non-infiltrated [Zr] or glass-infiltrated [Zr-G]) and sintering temperature (1450 °C [Zr-1450] or 1550 °C [Zr-1550]/2h). After sintering, the specimens were characterized by X-Ray Diffraction (XRD), relative density measurement, and scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS). The biaxial flexural strength test was performed according to the ISO 6872 and followed by fractographic analysis. Subsequent results were analyzed using Weibull statistics. Relative density values of the sintered specimens from Zr-1450 and Zr-1550 groups were 86.7 ± 1.5% and 92.2 ± 1.7%, respectively. Particle size distribution revealed particles within the range of 0.1-100 µm. XRD analysis highlighted the presence of the ZrO2-tetragonal in both the Zr-1450 and Zr-1550 groups. Glass infiltration, however, led to the formation of the ZrO2-monoclinic of 9.84% (Zr-1450-G) and 18.34% (Zr-1550-G). SEM micrographs demonstrated similar microstructural characteristics for Zr-1450 and Zr-1550, whereas the glass-infiltrated groups exhibited comparable infiltration patterns. The highest characteristic strength was observed in the glass-infiltrated groups. Fractographic analyses suggested that fracture origins were related to defects on the tensile side, which propagated to the compression side of the samples. Both the sintering temperature and glass infiltration significantly influenced the mechanical properties of the 3Y-TZP recycled.


Asunto(s)
Resistencia Flexional , Circonio , Temperatura , Ensayo de Materiales , Circonio/química , Itrio/química , Propiedades de Superficie , Materiales Dentales , Cerámica/química
18.
Materials (Basel) ; 16(24)2023 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-38138684

RESUMEN

Dental zirconias have been broadly utilized in dentistry due to their high mechanical properties and biocompatibility. Although initially introduced in dentistry as an infrastructure material, the high rate of technical complications related to veneered porcelain has led to significant efforts to improve the optical properties of dental zirconias, allowing for its monolithic indication. Modifications in the composition, processing methods/parameters, and the increase in the yttrium content and cubic phase have been presented as viable options to improve zirconias' translucency. However, concerns regarding the hydrothermal stability of partially stabilized zirconia and the trade-off observed between optical and mechanical properties resulting from the increased cubic content remain issues of concern. While the significant developments in polycrystalline ceramics have led to a wide diversity of zirconia materials with different compositions, properties, and clinical indications, the implementation of strong, esthetic, and sufficiently stable materials for long-span fixed dental prostheses has not been completely achieved. Alternatives, including advanced polycrystalline composites, functionally graded structures, and nanosized zirconia, have been proposed as promising pathways to obtain high-strength, hydrothermally stable biomaterials. Considering the evolution of zirconia ceramics in dentistry, this manuscript aims to present a critical perspective as well as an update to previous classifications of dental restorative ceramics, focusing on polycrystalline ceramics, their properties, indications, and performance.

19.
ACS Biomater Sci Eng ; 9(12): 6586-6609, 2023 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-37982644

RESUMEN

The field of craniomaxillofacial (CMF) surgery is rich in pathological diversity and broad in the ages that it treats. Moreover, the CMF skeleton is a complex confluence of sensory organs and hard and soft tissue with load-bearing demands that can change within millimeters. Computer-aided design (CAD) and additive manufacturing (AM) create extraordinary opportunities to repair the infinite array of craniomaxillofacial defects that exist because of the aforementioned circumstances. 3D printed scaffolds have the potential to serve as a comparable if not superior alternative to the "gold standard" autologous graft. In vitro and in vivo studies continue to investigate the optimal 3D printed scaffold design and composition to foster bone regeneration that is suited to the unique biological and mechanical environment of each CMF defect. Furthermore, 3D printed fixation devices serve as a patient-specific alternative to those that are available off-the-shelf with an opportunity to reduce operative time and optimize fit. Similar benefits have been found to apply to 3D printed anatomical models and surgical guides for preoperative or intraoperative use. Creation and implementation of these devices requires extensive preclinical and clinical research, novel manufacturing capabilities, and strict regulatory oversight. Researchers, manufacturers, CMF surgeons, and the United States Food and Drug Administration (FDA) are working in tandem to further the development of such technology within their respective domains, all with a mutual goal to deliver safe, effective, cost-efficient, and patient-specific CMF care. This manuscript reviews FDA regulatory status, 3D printing techniques, biomaterials, and sterilization procedures suitable for 3D printed devices of the craniomaxillofacial skeleton. It also seeks to discuss recent clinical applications, economic feasibility, and future directions of this novel technology. By reviewing the current state of 3D printing in CMF surgery, we hope to gain a better understanding of its impact and in turn identify opportunities to further the development of patient-specific surgical care.


Asunto(s)
Impresión Tridimensional , Prótesis e Implantes , Estados Unidos , Humanos , Regeneración Ósea , Materiales Biocompatibles
20.
Materials (Basel) ; 16(20)2023 Oct 10.
Artículo en Inglés | MEDLINE | ID: mdl-37895615

RESUMEN

Non-resorbable dental barrier membranes entail the risk of dehiscence due to their smooth and functionally inert surfaces. Non-thermal plasma (NTP) treatment has been shown to increase the hydrophilicity of a biomaterials and could thereby enhance cellular adhesion. This study aimed to elucidate the role of allyl alcohol NTP treatment of poly(tetrafluoroethylene) in its cellular adhesion. The materials (non-treated PTFE membranes (NTMem) and NTP-treated PTFE membranes (PTMem)) were subjected to characterization using scanning electron microscopy (SEM), contact angle measurements, X-ray photoelectron spectroscopy (XPS), and electron spectroscopy for chemical analysis (ESCA). Cells were seeded upon the different membranes, and cellular adhesion was analyzed qualitatively and quantitatively using fluorescence labeling and a hemocytometer, respectively. PTMem exhibited higher surface energies and the incorporation of reactive functional groups. NTP altered the surface topography and chemistry of PTFE membranes, as seen through SEM, XPS and ESCA, with partial defluorination and polymer chain breakage. Fluorescence labeling indicated significantly higher cell populations on PTMem relative to its untreated counterparts (NTMem). The results of this study support the potential applicability of allyl alcohol NTP treatment for polymeric biomaterials such as PTFE-to increase cellular adhesion for use as dental barrier membranes.

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