Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 138
Filtrar
1.
J Dent ; : 105256, 2024 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-39043329

RESUMO

OBJECTIVES: To present the first clinical application of a novel mixed reality-based dynamic navigation (MR-DN) system in the rehabilitation of a single tooth gap. METHODS: The protocol consisted of the following: (1) three-dimensional patient data acquisition using intraoral scanning (IOS) and cone-beam computed tomography (CBCT), (2) implant planning using guided surgery software, (3) holography-guided implant placement using the novel MR-DN system (ANNA®, MARS Dental, Haifa, Israel) and (4) placement accuracy verification. RESULTS: The novel MR-DN system was safe and time-efficient, as the surgery took 30 minutes from anaesthesia to suturing. The accuracy of implant placement was high with minimal deviations recorded in the three planes of space compared to the presurgical planning: the error at the entry point planar distance (XY) was 0.381 mm, and the entry point planar distance (Z) was 0.173 mm, for a 3D entry point distance (En) of 0.417 mm. A 3D apex deviation (An) of 0.193 mm was registered, with an angle difference of 1.852°. CONCLUSIONS: This proof-of-concept study demonstrated the clinical feasibility of MR-DN for guided implant placement in single tooth gaps. Further clinical studies on a large sample of patients are needed to confirm these positive preliminary results. Statement of clinical relevance: The use of MR-DN can change the perspectives of guided dental implant surgery as a possible alternative to the classic static and dynamic guided surgical techniques for the rehabilitation of single tooth gaps.

2.
Artigo em Inglês | MEDLINE | ID: mdl-38940681

RESUMO

AIM: The aim of this work is to present a new protocol for implant surgical planning which involves the combined use of artificial intelligence (AI) and mixed reality (MR). METHODS: This protocol involves the acquisition of three-dimensional (3D) patient data through intraoral scanning (IOS) and cone beam computed tomography (CBCT). These data are loaded into AI software which automatically segments and aligns the patient's 3D models. These 3D models are loaded into MR software and used for planning implant surgery through holography. The files are then exported and used to design surgical guides via open-source software, which are 3D printed and used to prepare the implant sites through static computer-assisted implant surgery (s-CAIS). The case is finalized prosthetically through a fully digital protocol. The accuracy of implant positioning is verified by comparing the planned position with the actual position of the implants after surgery. RESULTS: As a proof of principle, the present protocol seems to be to be reliable and efficient when used for planning simple cases of s-CAIS in partially edentulous patients. The clinician can plan the implants in an authentic 3D environment without using any radiology-guided surgery software. The precision of implant placement seems clinically acceptable, with minor deviations. CONCLUSIONS: The present study suggests that AI and MR technologies can be successfully used in s-CAIS for an authentic 3D planning. Further clinical studies are needed to validate this protocol.

3.
J Dent ; 146: 105052, 2024 07.
Artigo em Inglês | MEDLINE | ID: mdl-38734298

RESUMO

PURPOSE: This in vitro study aimed to compare the accuracy of dental implant placement in partially edentulous maxillary models using a mixed reality-based dynamic navigation (MR-DN) system to conventional static computer-assisted implant surgery (s-CAIS) and a freehand (FH) method. METHODS: Forty-five partially edentulous models (with teeth missing in positions #15, #16 and #25) were assigned to three groups (15 per group). The same experienced operator performed the model surgeries using an MR-DN system (group 1), s-CAIS (group 2) and FH (group 3). In total, 135 dental implants were placed (45 per group). The primary outcomes were the linear coronal deviation (entry error; En), apical deviation (apex error; Ap), XY and Z deviations, and angular deviation (An) between the planned and actual (post-surgery) position of the implants in the models. These deviations were computed as the distances between the stereolithographic (STL) files for the planned implants and placed implants captured with an intraoral scanner. RESULTS: Across the three implant sites, the MR-DN system was significantly more accurate than the FH method (in XY, Z, En, Ap and An) and s-CAIS (in Z, Ap and An), respectively. However, S-CAIS was more accurate than MR-DN in XY, and no difference was found between MR-DN and s-CAIS in En. CONCLUSIONS: Within the limits of this study (in vitro design, only partially edentulous models), implant placement accuracy with MR-DN was superior to that of FH and similar to that of s-CAIS. STATEMENT OF CLINICAL RELEVANCE: In vitro, MR-DN showed greater accuracy in implant positioning than FH, and similar accuracy to s-CAIS: it could, therefore, represent a new option for the surgeon. However, clinical studies are needed to determine the feasibility of MR-DN.


Assuntos
Implantação Dentária Endóssea , Implantes Dentários , Arcada Parcialmente Edêntula , Maxila , Modelos Dentários , Cirurgia Assistida por Computador , Humanos , Cirurgia Assistida por Computador/métodos , Implantação Dentária Endóssea/métodos , Maxila/cirurgia , Arcada Parcialmente Edêntula/cirurgia , Imageamento Tridimensional/métodos , Estereolitografia , Planejamento de Assistência ao Paciente , Tomografia Computadorizada de Feixe Cônico , Técnicas In Vitro
4.
J Dent ; 140: 104778, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-37951493

RESUMO

AIMS: The first aim of this study was to characterize the surface topography of a novel 3D-printed dental implant at the micro- and macro-level. Its second aim was to evaluate the osteogenic, angiogenic, and immunogenic responses of human oral osteoblasts (hOBs), gingival fibroblasts (hGFs), mesenchymal stem cells (hAD-MSCs), and monocytes to this novel implant surface. METHODS: A 3D-printed Ti-6Al-4 V implant was produced by selective laser melting and subjected to organic acid etching (TEST). It was then compared to a machined surface (CTRL). Its biological properties were evaluated via cell proliferation assays, morphological observations, gene expression analyses, mineralization assessments, and collagen quantifications. RESULTS: Scanning electron microscopy analysis showed that the TEST group was characterized by a highly interconnected porous architecture and a roughed surface. The morphological observations showed good adhesion of cells cultured on the TEST surface, with a significant increase in hOB growth. Similarly, the gene expression analysis showed significantly higher levels of osseointegration biomarkers. Picrosirius staining showed a slight increase in collagen production in the TEST group compared to the CTRL group. hAD-MSCs showed an increase in endothelial and osteogenic commitment-related markers. Monocytes showed increased mRNA synthesis related to the M2 (anti-inflammatory) macrophagic phenotype. CONCLUSIONS: Considering the higher interaction with hOBs, hGFs, hAD-MSCs, and monocytes, the prepared 3D-printed implant could be used for future clinical applications. CLINICAL RELEVANCE: This study demonstrated the excellent biological response of various cells to the porous surface of the novel 3D-printed implant.


Assuntos
Implantes Dentários , Células-Tronco Mesenquimais , Humanos , Porosidade , Monócitos , Osteoblastos , Fibroblastos , Células-Tronco Mesenquimais/metabolismo , Colágeno , Impressão Tridimensional , Titânio , Propriedades de Superfície
5.
J Dent ; 133: 104485, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36965859

RESUMO

PURPOSE: To present a novel protocol for authentic three-dimensional (3D) planning of dental implants, using artificial intelligence (AI) and augmented reality (AR). METHODS: The novel protocol consists of (1) 3D data acquisition, with an intraoral scanner (IOS) and cone-beam computed tomography (CBCT); (2) application of AI for CBCT segmentation to obtain standard tessellation language (STL) models and automatic alignment with IOS models; (3) loading of selected STL models within the AR system and surgical planning with holograms; (4) surgical guide design with open-source computer-assisted-design (CAD) software; and (5) surgery on the patient. RESULTS: This novel protocol is effective and time-efficient when used for planning simple cases of static guided implant surgery in the partially edentulous patient. The clinician can plan the implants in an authentic 3D environment, without using any radiological guided surgery software. The precision of implant placement looks clinically acceptable, with minor deviations. CONCLUSIONS: AI and AR technologies can be successfully used in guided implant surgery for authentic 3D planning that may replace conventional software. However, further clinical studies are needed to validate this protocol. STATEMENT OF CLINICAL RELEVANCE: The combined use of AI and AR may change the perspectives of modern guided implant surgery for authentic 3D planning that may replace conventional software.


Assuntos
Realidade Aumentada , Implantes Dentários , Cirurgia Assistida por Computador , Humanos , Implantação Dentária Endóssea/métodos , Inteligência Artificial , Cirurgia Assistida por Computador/métodos , Imageamento Tridimensional , Desenho Assistido por Computador , Tomografia Computadorizada de Feixe Cônico/métodos
6.
J Dent ; 127: 104323, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36241044

RESUMO

PURPOSE: To report on the results obtained with computer-aided-design/ computer-assisted-manufacturing (CAD/CAM) custom-made synthetic hydroxyapatite/beta-tricalcium-phosphate (HA/beta-TCP) bone grafts in alveolar ridge augmentation for dental implant placement. METHODS: The procedure included: (1) cone-beam computed tomography (CBCT) of the bone defect; (2) virtual design of the custom-made onlay bone grafts; (3) milling of grafts from a pre-formed block of synthetic HA/beta-TCP; and (4) bone reconstructive surgery. Implants were placed 8 months later. The patients were followed for 3 years. The study outcomes were: (1) intra- and immediate post-operative complications; (2) 8-month vertical and horizontal bone gain; (3) implant survival; (4) implant-crown success; and (5) peri-implant marginal bone loss (MBL). RESULTS: Twenty-six patients underwent ridge augmentation with custom-made CAD/CAM HA/beta-TCP onlay grafts. Eight months later, these patients were rehabilitated with dental implants. During surgery, 25/26 (96.1%) of the grafts adapted well to the bone defect. Immediate post-operative complications were pain and swelling (2/26 patients: 7.6%), and bone graft exposure (3/26: 11.5%); one exposure led to infection, removal of the graft, and failure of the procedure. Excellent integration of the other grafts was observed 8 months after the regenerative procedure, with mean vertical and horizontal bone gains of 2.10 mm (± 0.35) and 2.96 mm (± 0.45), respectively. Twenty-five implants were placed and restored with single crowns. Three years later, all implants were in function. The 3-year implant crown success rate and peri-implant MBL were 92.0% and 0.7 mm (±0.19), respectively. CONCLUSIONS: With custom-made CAD/CAM synthetic HA/beta-TCP onlay grafts reconstruction of small vertical and/or horizontal defects of the alveolar ridge was obtained; this enabled implant placement, with high implant-crown success rate after 3 years. Further studies are needed to validate this technique. STATEMENT OF CLINICAL RELEVANCE: Custom-made CAD/CAM synthetic HA/beta-TCP onlay grafts may represent an option for regeneration of small bone defects prior to implant placement.


Assuntos
Aumento do Rebordo Alveolar , Implantes Dentários , Humanos , Aumento do Rebordo Alveolar/métodos , Estudos Retrospectivos , Seguimentos , Transplante Ósseo/métodos , Computadores , Implantação Dentária Endóssea/métodos , Resultado do Tratamento
7.
Molecules ; 27(17)2022 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-36080495

RESUMO

In this paper, we report on the preparation of Imidazole-functionalized glass surfaces, demonstrating the ability of a dinuclear Cu(II) complex of a macrocyclic ligand to give a "cascade" interaction with the deprotonated forms of grafted imidazole moieties. In this way, we realized a prototypal example of an antimicrobial surface based on a supramolecular approach, obtaining a neat microbicidal effect using low amounts of the described copper complex.


Assuntos
Antibacterianos , Cobre , Antibacterianos/farmacologia , Vidro , Imidazóis/farmacologia , Ligantes
8.
Artigo em Inglês | MEDLINE | ID: mdl-35805602

RESUMO

BACKGROUND: In more than three decades of work of the Retrieval Bank of the Laboratory for Undemineralized Hard Tissue Histology of the University of Chieti-Pescara in Italy, many types of biomaterials were received and evaluated. The present retrospective review aimed to evaluate the histological and biological aspects of the evaluated bone substitute biomaterials. METHODS: In the present study, the authors prepared a retrospective analysis after the screening of some databases (PubMed, Scopus, and EMBASE) to find papers published from the Retrieval Bank of the Laboratory for Undermineralized Hard Tissue Histology of the University of Chieti-Pescara analyzing only the papers dealing with bone substitute biomaterials and scaffolds, in the form of granules and block grafts, for bone regeneration procedures. RESULTS: Fifty-two articles were found, including in vitro, in vivo, and clinical studies of different biomaterials. These articles were evaluated and organized in tables for a better understanding. CONCLUSIONS: Over three decades of studies have made it possible to assess the quality of many bone substitute biomaterials, helping to improve the physicochemical and biological properties of the biomaterials used in daily clinical practice.


Assuntos
Substitutos Ósseos , Materiais Biocompatíveis/química , Regeneração Óssea , Substitutos Ósseos/química , Substitutos Ósseos/uso terapêutico , Itália , Estudos Retrospectivos
9.
Biomimetics (Basel) ; 7(1)2022 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-35323189

RESUMO

Ten years ago, for the first time in humans, thanks to the DLMS (direct metal laser sintering) technique, we designed, built and inserted an immediate post-extraction custom-made root-analogue implant in Ti-6Al-4v with platform switching. The implant was inserted into the post-extraction socket, respecting the biological width. After 10 years, we wanted to evaluate the dimensional stability of the implant and the eventual crestal bone resorption. The evaluation was performed clinically with periodontal parameters and radiographically by means of an intraoral X-ray with the parallel technique measuring the distance between the base of the bone crest and the implant shoulder. It appears that the implant has maintained dimensional stability of the peri-implant soft tissues, and the crestal resorption is 0 mm. This could represent a step forward to make this experimental method a valid alternative to the current immediate post-extraction implant procedures in use.

10.
J Dent ; 116: 103886, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34762988

RESUMO

AIM: This in vitro study aimed to compare the mechanical performance of 3D printed versus milled zirconia blocks, when subjected to uniaxial compression load, and to investigate the microstructural characteristics of the 3D printed samples, before and after the application of the load. METHODS: Twenty zirconia blocks (5 × 5 × 5mm3) were prepared: 10 (tests) were 3D printed with a Lithography-based Ceramic Manufacturing (LCM) printer (Cerafab S65®, Lithoz, Vienna, Austria), and 10 (controls) were milled with a 5-axis milling machine (DWX-52D®, DGShape, a Roland Company, Hamamatsu, Japan). Compression tests were carried out on all samples, using a load cell of 30 kN and crosshead speed of 0.5 mm/min, in according to the ASTM C1424-15. The elastic modulus of the material was calculated from stress/strain curve by taking compressive stress values between 50 MPa and 100 MPa. Compression data obtained were plotted as stress-strain curves. Finally, the 3D printed test samples were also observed by VEGA3 Tescan scanning electron microscope (SEM) to detect the presence of eventual defects on surface before and after compression. A statistical analysis was performed to compare the elastic modulus and the deformation in compression at maximum load of the test samples that did not break and the control samples. RESULTS: Under mechanical compression, four of the test samples reached failure, whereas all the control samples did not reach failure at the limit of the load cell. However, the 3D printed samples that did not break revealed interesting properties, such as a better modulus of elasticity (p = 0.15) and a lower tendency to deformation under compression (p<0.001), when compared to the milled ones. CONCLUSIONS: Within the limits of this study (experimental setting, in vitro design, only one type of force applied) milled zirconia blocks were found more resistant to compression forces than 3D printed ones.


Assuntos
Desenho Assistido por Computador , Zircônio , Cerâmica/química , Porcelana Dentária/química , Análise do Estresse Dentário , Teste de Materiais , Zircônio/química
11.
Materials (Basel) ; 14(18)2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34576532

RESUMO

Titanium specimens have been proven to be safe and effective biomaterials in terms of their osseo-integration. To improve the bioactivity and develop customized implants titanium, the surface can be modified with selective laser melting (SLM). Moreover, the design of macro-porous structures has become popular for reaching a durable bone fixation. 3D-printed titanium (Titanium A, B, and C), were cleaned using an organic acid treatment or with electrochemical polishing, and were characterized in terms of their surface morphology using scanning electron microscopy. Next, Dental Pulp Stem Cells (DPSCs) were cultured on titanium in order to analyze their biocompatibility, cell adhesion, and osteoconductive properties. All tested specimens were biocompatible, due to the time-dependent increase of DPSC proliferation paralleled by the decrease of LDH released. Furthermore, data highlighted that the open cell form with interconnected pores of titanium A, resembling the inner structure of the native bone, allows cells to better adhere inside the specimen, being proteins related to cell adherence highly expressed. Likewise, titanium A displays more suitable osteoconductive properties, being the profile of osteogenic markers improved compared to titanium B and C. The present work has demonstrated that the inner design and post-production treatments on titanium surfaces have a dynamic influence on DPSC behavior toward adhesion and osteogenic commitment.

13.
Int J Comput Dent ; 24(3): 331-343, 2021 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-34553897

RESUMO

OBJECTIVES: To present a solid index (SI), a 3D-printed replica of a patient's preexisting complete denture, which allows the dentist to accurately capture the position of the implants and the dental technician to model a bar for overdenture (OD) in CAD software with the use of reverse implant libraries. MATERIALS AND METHODS: A patient in need of rehabilitation of a fully edentulous mandible was restored with an implant OD supported by a polyetheretherketone (PEEK) milled bar. The position of the implants was captured through a physical impression using an SI, with the transfers screwed in. The analogs were then connected, and the SI was scanned upside down to directly capture the position of the implants in the space. This scan was used to design the bar in CAD software using reverse implant libraries, without the need for pouring any SI-derived cast or for using any scanbody. The bar was milled in PEEK. RESULTS: When delivered to the patient, the bar was clinically precise, screwing perfectly onto the implants without any tension or misfit. CONCLUSIONS: The present proof-of-concept article supports the use of an SI and reverse implant libraries for the fabrication of a bar for OD. Further clinical studies are needed to confirm these results.


Assuntos
Implantes Dentários , Arcada Edêntula , Prótese Dentária Fixada por Implante , Retenção de Dentadura , Revestimento de Dentadura , Humanos , Mandíbula
14.
Front Bioeng Biotechnol ; 9: 614325, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33937211

RESUMO

Introduction: Dental implant placement can be challenging when insufficient bone volume is present and bone augmentation procedures are indicated. The purpose was to assess clinically and histologically a specimen of 30%HA-60%ß-TCP BCP 3D-printed scaffold, after 7-years. Case Description: The patient underwent bone regeneration of maxillary buccal plate with 3D-printed biphasic-HA block in 2013. After 7-years, a specimen of the regenerated bone was harvested and processed to perform microCT and histomorphometrical analyses. Results: The microarchitecture study performed by microCT in the test-biopsy showed that biomaterial volume decreased more than 23% and that newly-formed bone volume represented more than 57% of the overall mineralized tissue. Comparing with unloaded controls or peri-dental bone, Test-sample appeared much more mineralized and bulky. Histological evaluation showed complete integration of the scaffold and signs of particles degradation. The percentage of bone, biomaterials and soft tissues was, respectively, 59.2, 25.6, and 15.2%. Under polarized light microscopy, the biomaterial was surrounded by lamellar bone. These results indicate that, while unloaded jaws mimicked the typical osteoporotic microarchitecture after 1-year without loading, the BCP helped to preserve a correct microarchitecture after 7-years. Conclusions: BCP 3D-printed scaffolds represent a suitable solution for bone regeneration: they can lead to straightforward and less time-consuming surgery, and to bone preservation.

15.
Materials (Basel) ; 14(9)2021 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-33922799

RESUMO

Maxillary sinus augmentation is often necessary prior to implantology procedure, in particular in cases of atrophic posterior maxilla. In this context, bone substitute biomaterials made of biphasic calcium phosphates, produced by three-dimensional additive manufacturing were shown to be highly biocompatible with an efficient osteoconductivity, especially when combined with cell-based tissue engineering. Thus, in the present research, osteoinduction and osteoconduction properties of biphasic calcium-phosphate constructs made by direct rapid prototyping and engineered with ovine-derived amniotic epithelial cells or amniotic fluid cells were evaluated. More in details, this preclinical study was performed using adult sheep targeted to receive scaffold alone (CTR), oAFSMC, or oAEC engineered constructs. The grafted sinuses were explanted at 90 days and a cross-linked experimental approach based on Synchrotron Radiation microCT and histology analysis was performed on the complete set of samples. The study, performed taking into account the distance from native surrounding bone, demonstrated that no significant differences occurred in bone regeneration between oAEC-, oAFMSC-cultured, and Ctr samples and that there was a predominant action of the osteoconduction versus the stem cells osteo-induction. Indeed, it was proven that the newly formed bone amount and distribution decreased from the side of contact scaffold/native bone toward the bulk of the scaffold itself, with almost constant values of morphometric descriptors in volumes more than 1 mm from the border.

16.
Dalton Trans ; 50(5): 1620-1630, 2021 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-33470269

RESUMO

The extraction of technetium, present in nitric acid medium as pertechnetate anion, is an issue in solvent extraction processes used to recover uranium and plutonium. In the present study, a complexing agent is added in the aqueous nitric acid solution to bind selectively the pertechnetate anion and prevent its extraction into the organic phase or to back extract it in the aqueous phase. Several azacryptands with the addition of hydrophilic groups were synthesized to improve the solubility of the previously studied cage molecule in nitric acid medium. Solvent extraction tests reveal that all the synthesized ligands have a similar complexation strength towards pertechnetate and are able to maintain this anion in the aqueous phase (0.5 M HNO3). These ligands are able to overcome the Hofmeister bias and selectively bind technetium in nitric acid solution. The azacryptand concentration can be increased by a factor of three in the liquid-liquid extraction conditions compared to our previous work. Coordination studies using microcalorimetry, Single Crystal X-Ray Diffraction (SC-XRD), infrared and Raman spectroscopies show the formation of an inclusion complex with hydrogen bonds stabilizing the oxo-anion within the cavity. This solubility improvement is promising for the introduction of this kind of macrocyclic azacryptands in a solvent extraction process.

17.
Chemistry ; 27(4): 1306-1310, 2021 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-33064343

RESUMO

Benzene is a highly toxic aromatic hydrocarbon. Inhaling benzene can cause dizziness, vertigo, headaches, aplasia, mutations and, in the most extreme cases, cancer. Trans,trans-muconic acid (t,t-MA) is one of the metabolization products of benzene. Although different analytical methods have been reported for the determination of t,t-MA, these are often expensive, require trained personnel, are not suitable for on-site measurements, and use hazardous organic solvents. For these reasons, the development of reliable, selective and sensitive methods for rapid and in situ detection of t,t-MA are of importance. Addressing this challenge, a nanodevice for the selective and sensitive quantification of t,t-MA in urine is reported. The nanodevice used is achieved using mesoporous silica nanoparticles loaded with a dye reporter and capped with a dicopper(II) azacryptand. Pore opening and payload release is induced rapidly (10 min) and selectively with t,t-MA in urine, using a simple fluorimeter without sample pretreatment.


Assuntos
Benzeno , Nanopartículas , Biomarcadores , Dióxido de Silício/química , Ácido Sórbico/análogos & derivados , Ácido Sórbico/química , Ácido Sórbico/metabolismo
18.
Int J Periodontics Restorative Dent ; 40(6): e211-e227, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33151185

RESUMO

For decades, the histologic evidence about osseointegration and the bone-implant interface has been discussed in the literature. In this review, the effectiveness of dental implants retrieved for different causes was evaluated. A literature search was performed in databases for papers about implants retrieved from humans published by the Implant Retrieval Center of the University of Chieti-Pescara, Italy. Sixty-eight articles were selected into categories based on topics. The data indicated high level of bone-to-implant contact, lamellar bone close to the surface, roughness related to an increased bone response, organized and remodeled bone after loading, and peri-implant interfaces subjected to a continuous dynamic function.


Assuntos
Implantes Dentários , Osso e Ossos , Implantação Dentária Endóssea , Humanos , Itália , Osseointegração , Estudos Retrospectivos , Propriedades de Superfície
19.
BMC Oral Health ; 20(1): 263, 2020 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-32962680

RESUMO

BACKGROUND: The literature has not yet validated the use of intraoral scanners (IOSs) for full-arch (FA) implant impression. Hence, the aim of this in vitro study was to assess and compare the trueness of 12 different IOSs in FA implant impression. METHODS: A stone-cast model of a totally edentulous maxilla with 6 implant analogues and scanbodies (SBs) was scanned with a desktop scanner (Freedom UHD®) to capture a reference model (RM), and with 12 IOSs (ITERO ELEMENTS 5D®; PRIMESCAN® and OMNICAM®; CS 3700® and CS 3600®; TRIOS3®; i-500®; EMERALD S® and EMERALD®; VIRTUO VIVO® and DWIO®; RUNEYES QUICKSCAN®). Ten scans were taken using each IOS, and each was compared to the RM, to evaluate trueness. A mesh/mesh method and a nurbs/nurbs method were used to evaluate the overall trueness of the scans; linear and cross distances between the SBs were used to evaluate the local trueness of the scans. The analysis was performed using reverse engineering software (Studio®, Geomagics; Magics®, Materialise). A statistical evaluation was performed. RESULTS: With the mesh/mesh method, the best results were obtained by CS 3700® (mean error 30.4 µm) followed by ITERO ELEMENTS 5D® (31.4 µm), i-500® (32.2 µm), TRIOS 3® (36.4 µm), CS 3600® (36.5 µm), PRIMESCAN® (38.4 µm), VIRTUO VIVO® (43.8 µm), RUNEYES® (44.4 µm), EMERALD S® (52.9 µm), EMERALD® (76.1 µm), OMNICAM® (79.6 µm) and DWIO® (98.4 µm). With the nurbs/nurbs method, the best results were obtained by ITERO ELEMENTS 5D® (mean error 16.1 µm), followed by PRIMESCAN® (19.3 µm), TRIOS 3® (20.2 µm), i-500® (20.8 µm), CS 3700® (21.9 µm), CS 3600® (24.4 µm), VIRTUO VIVO® (32.0 µm), RUNEYES® (33.9 µm), EMERALD S® (36.8 µm), OMNICAM® (47.0 µm), EMERALD® (51.9 µm) and DWIO® (69.9 µm). Statistically significant differences were found between the IOSs. Linear and cross distances between the SBs (local trueness analysis) confirmed the data that emerged from the overall trueness evaluation. CONCLUSIONS: Different levels of trueness were found among the IOSs evaluated in this study. Further studies are needed to confirm these results.


Assuntos
Técnica de Moldagem Odontológica , Modelos Dentários , Desenho Assistido por Computador , Arco Dental , Imageamento Tridimensional , Maxila/diagnóstico por imagem
20.
Artigo em Inglês | MEDLINE | ID: mdl-32650587

RESUMO

PURPOSE: Several studies showed that the sintering temperature of 1250 °C could affect the formation of α-Ca3(PO4)2, which is responsible for the reduction of the hardness value of biphasic calcium phosphate biocomposites, but they did not evaluate the inference of the sintering time at peak temperature on transition of ß-Ca3(PO4)2 to α-Ca3(PO4)2. This analysis explored, in an innovative way, inferences and correlations between volumetric microstructure, mechanical properties, sintering temperature, and time at peak temperature in order to find the best sintering conditions for biphasic calcium phosphate composites grafted in severe alveolar bone defects. METHODS: Sintered biphasic calcium phosphates (30%-hydroxyapatite/70%-tricalcium phosphate) were tested by microCT imaging for the 3D morphometric analysis, by compressive loading to find their mechanical parameters, and by X-ray diffraction to quantify the phases via Rietveld refinement for different sintering temperatures and times at the peak temperature. Data were analysed in terms of statistical inference using Pearson's correlation coefficients. RESULTS: All the studied scaffolds closely mimicked the alveolar organization of the jawbone, independently on the sintering temperatures and times; however, mechanical testing revealed that the group with peak temperature, which lasted for 2 hours at 1250 °C, showed the highest strength both at the ultimate point and at fracture point. CONCLUSION: The good mechanical performances of the group with peak temperature, which lasted for 2 hours at 1250 °C, is most likely due to the absence of the α-Ca3(PO4)2 phase, as revealed by X-ray diffraction. However, we detected its presence after sintering at the same peak temperature for longer times, showing the time-dependence, combined with the temperature-dependence, of the ß-Ca3(PO4)2 to α-Ca3(PO4)2 transition.


Assuntos
Substitutos Ósseos , Hidroxiapatitas , Materiais Biocompatíveis , Durapatita , Difração de Raios X
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...