Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Artículo en Inglés | MEDLINE | ID: mdl-33583693

RESUMEN

INTRODUCTION: This retrospective clinical study aimed to evaluate the efficacy of different types of incisor movements with clear aligners in the sagittal plane. METHODS: Pretreatment and posttreatment cone-beam computed tomography (CBCT) scans were collected from 69 patients who underwent nonextraction treatment with clear aligners (Invisalign; Align Technology, San Jose, Calif). Integrated 3-dimensional models of the virtual incisor position (ClinCheck; Align Technology) and the posttreatment incisor position (from posttreatment CBCT scans) were superimposed over the pretreatment position (from pretreatment CBCT scans) using Mimics software (Materialise, Leuven, Belgium). On the basis of the location of the rotation center, incisors showing pure tipping (>10°), controlled tipping (>10°), translation (>1 mm), or torque (>10°) movements were selected. Efficacy was determined by comparing the predicted and achieved incisor movement, and differences with efficacy were analyzed using Kruskal-Wallis and Shapiro-Wilk tests (α = 0.05). RESULTS: In measurements for 231 incisors, the mean efficacy of incisor movements in the sagittal plane was 55.58%. The most and least predictable movements were pure tipping (72.48%) and torque (35.21%), respectively. Labial root movement was significantly more predictable than lingual root movement, and labial movement of the mandibular incisors was significantly easier than that of the maxillary incisors. The type of tooth movement achieved was different from the type designed. CONCLUSIONS: The efficacy of incisor movement in the sagittal plane using clear aligners varies with designed movement type, and labial root movement appears to be more accurate than the lingual root movement. The biomechanics of clear aligners remains to be further elucidated to achieve more predictable treatment results.

2.
Shanghai Kou Qiang Yi Xue ; 25(5): 522-526, 2016 Oct.
Artículo en Chino | MEDLINE | ID: mdl-28116420

RESUMEN

PURPOSE: To investigate the influence of lyophilization on the biological activity of recombinant lentiviral vectors of bone morphogenetic protein 2(BMP-2). METHODS: Recombinant lenti-BMP-2 was constructed. lenti-BMP-2 was transfected with rat bone marrow stromal cells (BMSCs) by multiplicity infection (MOI) of 10, 25, 50, 100, 200. The infection efficiency was observed by X-gal staining. Under suitable conditions, the lenti-BMP-2 and 10% trehalose ratio of lyophilized protective agent was mixed into the lyophilization form. Before and after lyophilization, the effect of lenti-BMP-2 on the proliferation of BMSCs was evaluated by MTS assay. The expression of BMP-2 protein in the cells of lyophilized lenti-BMP-2 was detected by ELISA method. The expression of Runx-2, OCN, Col1 and OPN in BMSCs was detected by real-time PCR after transfection of lyophilized lenti-BMP-2. SPSS13.0 software package was used for statistical analysis. RESULTS: X-gal staining showed an MOI of 100 pfu/cell, and stable transfection efficiency. Before and after lyophilization, no significant change was observed in regard to the effect of lyophilized lenti-BMP-2 on BMSCs proliferation (P>0.05). ELISA method showed that BMSCs transfected by lyophilized lenti-BMP-2 could express BMP-2 protein continuously and stably at a high level. Before and after lyophilization, the result of real-time PCR showed that no significant difference in the expression of OPN,Col1,OCN and Runx-2 in BMSCs (P>0.05). CONCLUSIONS: Lyophilized lenti-BMP-2 with trehalose can maintain high activity for a long time as an effective and reliable storage method.


Asunto(s)
Proteína Morfogenética Ósea 2/genética , Vectores Genéticos , Animales , Células de la Médula Ósea , Proteína Morfogenética Ósea 2/metabolismo , Diferenciación Celular , Células Cultivadas , Galactósidos , Indoles , Células Madre Mesenquimatosas , Osteogénesis , Ratas , Reacción en Cadena en Tiempo Real de la Polimerasa , Proteínas Recombinantes , Transfección , Factor de Crecimiento Transformador beta
3.
Shanghai Kou Qiang Yi Xue ; 23(3): 333-6, 2014 Jun.
Artículo en Chino | MEDLINE | ID: mdl-25102878

RESUMEN

PURPOSE: To study the growth phases and quantities of mandible in Shanghai adolescents. METHODS: The samples included 480 Shanghai adolescents from 8-20 years of age, 240 were male and 240 were female. Both male and female groups were divided into 6 consecutive developmental periods according to cervical vertebral maturation stages. Their cephalometric radiographs were measured and analyzed. Independent-sample t test was conducted by SPSS 15.0 software package. RESULTS: The total mandibular length (Co-Gn) increased significantly from CVMS1 to CVMS2 and CVMS3 to CVMS4 in both male and female group. For male the maximum increase was from CVMS3 to CVMS4 (P<0.01,average 9.54 mm), while female was from CVMS1 to CVMS2(P<0.01,average 9.09 mm). The height of mandibular ramus (Co-Go) increased continuously from CVMS2 to CVMS5 in male group, the significant increase was observed from CVMS2 to CVMS3 (P<0.01, average 8.80 mm). The significant increase in female group was observed from CVMS1 to CVMS2 (P<0.01, average 6.51 mm). In male group, the greatest increase of the mandibular base length (Go-Pog) appeared from CVMS3 to CVMS4 (P<0.01, average 7.55 mm), while in female group, it occurred from CVMS1 to CVMS2 (P<0.01, average 5.73 mm). CONCLUSIONS: The growth amounts of total mandibular length (Co-Gn), mandibular base length (Go-Pog) and ramus length are different at every CVM stages in male and female groups. The present finding will help to make reasonable diagnosis and treatment planning.


Asunto(s)
Cefalometría , Mandíbula/crecimiento & desarrollo , Adolescente , China , Femenino , Humanos , Masculino
4.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 48(9): 550-3, 2013 Sep.
Artículo en Chino | MEDLINE | ID: mdl-24314282

RESUMEN

OBJECTIVE: To evaluate the design and manufacture accuracy of a domestic computer aided design (CAD) and computer aided manufacture (CAM) system, and to compare it with similar foreign products. METHODS: Thirty models of posterior-teeth-single-crown preparations were collected, and STL data of these preparations was collected by Denmark 3Shape scanner. Three copings were made for each preparation, the one designed and manufactured using commercial CAD/CAM system (3Shape CAD software and Wieland T1 CAM equipment) was assigned into control group T0, the one designed and manufactured using domestic CAD software (developed by Peking University School and Hospital of Stomatology and Nanjing University of Aeronautics and Astronautics) and Wieland T1 CAM equipment was assigned into experimental group TCAD for design accuracy evaluation, and the one designed and manufactured using 3Shape CAD software and domestic CAM equipment (developed by Peking University School and Hospital of Stomatology, Tsinghua University and ShanDong XinHua Incorporated Company of medical apparatus and instruments) was assigned into experimental group TCAM for manufacture accuracy evaluation. Finally, the marginal fitness were compared and evaluated by using 3D & Profile measurement microscope laser. RESULTS: The marginal fitness of TCAD was 27.98 (19.10, 46.57) µm in buccal, 32.67 (20.65, 50.82) µm in lingual, 27.38 (22.53, 52.61) µm in mesial, 29.50 (22.68, 53.65) µm in distal; of TCAM was 21.69 (15.87, 30.21) µm in buccal, 18.51 (13.50, 22.51) µm in lingual, 19.15 (15.42, 26.89) µm in mesial, 22.77 (18.58, 32.15) µm in distal; and there were no statistical differences compared with T0 [20.16 (17.16, 48.00) µm in buccal, 21.51 (17.05, 28.31) µm in lingual, 23.54 (17.89, 30.04) µm in mesial and 23.94 (17.93, 28.19) µm in distal] except lingual data of TCAD. CONCLUSIONS: The design and machining precision of this domestic CAD/CAM system is at the same level of those comparable foreign products.


Asunto(s)
Diseño Asistido por Computadora , Coronas , Programas Informáticos , China , Coronas/normas , Adaptación Marginal Dental , Humanos
6.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 48(6): 355-8, 2013 Jun.
Artículo en Chino | MEDLINE | ID: mdl-24120005

RESUMEN

OBJECTIVE: To evaluate clinical effects of computer aided design and computer aided manufacturing (CAD/CAM) milled zirconia crown in three aspects: aesthetic, contact wear and fracture. METHODS: Sixty patients were divided into two groups.In one group, 35 full contour CAD/CAM zirconia crown were made on molars of 30 patients. The manufacturing process of zirconia crown was as follow. First, the three dimensional(3-D) data of working models, antagonist impression and check records were acquired by 3-D laser scanning Dental wings S50. Then full contour zirconia crowns, which had functional occlusal contacts with antagonistic teeth, and appropriate contact with adjacent teeth were designed with Zeno-CAD(V4.2.5.5.12919) software. ZENOSTAR Zr pure zirconia material was milled in digital controlled machine WIELAND 4030 M1.In the end, the zirconia crown were completed with the method of second sintering and polishing. After clinical try-in, the crown was cemented.In the control group, thirty gold alloy full crown were made and cemented on molars of 30 patients. According to the modified U S Public Health Service Criteria(USPHS) evaluation standard, all crowns were evaluated on the same day, at three months, half a year, one year and two years following delivery. There were three aspects we were focusing on in the evaluation: aesthetic, contact wear(restoration and antagonist), and fracture. RESULTS: In all the prosthesis we evaluated during the 24 months, no fracture was found. Contact wear of crowns varies according to different antagonist teeth. CONCLUSIONS: The zirconia crowns show privilege in aesthesis, toughness and anti-wearing.However, there is contact wear on antagonistic natural teeth. Thus it is a good choice when full zirconia crowns are indicated on two antagonistic teeth in both jaws.


Asunto(s)
Diseño Asistido por Computadora , Coronas , Porcelana Dental , Diseño de Prótesis Dental , Circonio , Adulto , Alisadura de la Restauración Dental , Femenino , Humanos , Masculino , Persona de Mediana Edad , Diente Molar , Adulto Joven
7.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 48(5): 299-302, 2013 May.
Artículo en Chino | MEDLINE | ID: mdl-24004627

RESUMEN

OBJECTIVE: To measure the effect of laser fluence and scanning velocity on ablation efficiency of enamel and dentin. METHODS: Two extracted human incisors and two molars were cut transversely along the axial plane with a diamond saw to obtain dentin and enamel slices with thickness of about 1 mm. Samples were fixed on a motorized translation stage, the linear reciprocating movement in the plane perpendicular to the direction of laser incident was programmed by the controller, and the laser focused on the tooth surface, then 36 ablation lines on enamel and 48 ablation lines on dentin were produced. A femtosecond laser system with wavelength of 800 nm, pulse width 30 fs, repetition frequency 1000 Hz was used, and the diameter of the focused spot was approximately 25 µm. A group of different fluence (1.33, 1.77, 2.21, 4.42, 8.85, 17.69 J/cm(2) for enamel and 0.44, 0.66, 0.88, 1.33, 1.77, 2.21, 4.42, 6.63 J/cm(2) for dentin) and two scanning velocity (10 mm/s and 20 mm/s) were tested. Confocal laser scanning microscope was used to measure the ablation volume.Ablation efficiency for enamel and dentin was then calculated. RESULTS: Under the fluence of 8.85 J/cm(2) there was the highest ablation efficiency for enamel, 18.703×10(-3) mm(3)/J (20 mm/s), and the highest ablation efficiency for dentin was found under the fluence of 2.21 J/cm(2), ie.223.458×10(-3) mm(3)/J (20 mm/s). CONCLUSIONS: Fluence and scanning speed of this femtosecond laser can affect ablation efficiency for both enamel and dentin, and this suggests that with appropriate choice of fluence and scanning speed we can improve the ablation efficiency for enamel and dentin.


Asunto(s)
Esmalte Dental/efectos de la radiación , Dentina/efectos de la radiación , Rayos Láser , Humanos , Incisivo/anatomía & histología , Diente Molar/anatomía & histología
8.
Int J Oral Sci ; 5(3): 155-61, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23907676

RESUMEN

The article introduces a new method for three-dimensional reproduction of edentulous dental casts, and wax occlusion rims with jaw relation by using a commercial high-speed line laser scanner and reverse engineering software and evaluates the method's accuracy in vitro. The method comprises three main steps: (i) acquisition of the three-dimensional stereolithography data of maxillary and mandibular edentulous dental casts and wax occlusion rims; (ii) acquisition of the three-dimensional stereolithography data of jaw relations; and (iii) registration of these data with the reverse engineering software and completing reconstruction. To evaluate the accuracy of this method, dental casts and wax occlusion rims of 10 edentulous patients were used. The lengths of eight lines between common anatomic landmarks were measured directly on the casts and occlusion rims by using a vernier caliper and on the three-dimensional computerized images by using the software measurement tool. The direct data were considered as the true values. The paired-samples t-test was used for statistical analysis. The mean differences between the direct and the computerized measurements were mostly less than 0.04 mm and were not significant (P>0.05). Statistical significance among 10 patients was assessed using one-way analysis of variance (P<0.05). The result showed that the 10 patients were considered statistically no significant. Therefore, accurate three-dimensional reproduction of the edentulous dental casts, wax occlusion rims, and jaw relations was achieved. The proposed method enables the visualization of occlusion from different views and would help to meet the demand for the computer-aided design of removable complete dentures.


Asunto(s)
Modelos Dentales , Precisión de la Medición Dimensional , Imagenología Tridimensional/métodos , Registro de la Relación Maxilomandibular , Boca Edéntula , Análisis de Varianza , Diseño Asistido por Computadora , Diseño de Dentadura , Dentadura Completa , Humanos , Rayos Láser , Boca Edéntula/rehabilitación , Ceras
10.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 47(8): 486-9, 2012 Aug.
Artículo en Chino | MEDLINE | ID: mdl-23141659

RESUMEN

OBJECTIVE: To establish the femtosecond laser experimental platform in vitro for numerical controlled cavity preparation, and to evaluate the roughness quantitatively and observe the microscopic morphology of the cutting surface. METHODS: Enamel and dentin planes were prepared on human third molars. A universal motion controller was used to control the samples to do rectangle wave motion perpendicular to the incident direction of the laser at focus. The surface roughness was observed with confocal laser scanning microscope. RESULTS: Precise ablation of the dental hard tissues can be achieved with the established femtosecond laser numerical control platform. For enamel, the surface roughness of the cavity inside laser scanning line was 7.173 µm at the bottom and 2.675 µm on the wall of the cavity. The surface roughness of the cavity between laser scanning lines was 13.667 µm at the bottom and 33.927 µm on the wall. For dentin, the surface roughness of the cavity bottom was 51.182 µm and 25.629 µm for the wall. Scanning electron microscope images showed no micro-cracks or carbonization on enamel, while carbonization, cracks and a small amount of crystalline particles were observed on dentin. CONCLUSIONS: Precise tooth preparation can be achieved with femtosecond laser numerical control flatform. The surface roughness of cavity wall was less than that of the bottom and can meet the clinical needs. Suitable femtosecond laser output power should be set for different cutting objects, otherwise it may result in tissue damages.


Asunto(s)
Esmalte Dental/cirugía , Dentina/cirugía , Terapia por Láser/métodos , Tercer Molar/cirugía , Preparación de la Cavidad Dental/métodos , Esmalte Dental/ultraestructura , Dentina/ultraestructura , Dureza , Humanos , Microscopía Electrónica de Rastreo , Tercer Molar/ultraestructura , Propiedades de Superficie
11.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 45(8): 457-61, 2010 Aug.
Artículo en Chino | MEDLINE | ID: mdl-21122360

RESUMEN

OBJECTIVE: To introduce a method of digital modeling and fabricating removable partial denture (RPD) frameworks using self-developed software for RPD design and rapid manufacturing system. METHODS: The three-dimensional data of two partially dentate dental casts were obtained using a three-dimensional crossing section scanner. Self-developed software package for RPD design was used to decide the path of insertion and to design different components of RPD frameworks. The components included occlusal rest, clasp, lingual bar, polymeric retention framework and maxillary major connector. The design procedure for the components was as following: first, determine the outline of the component. Second, build the tissue surface of the component using the scanned data within the outline. Third, preset cross section was used to produce the polished surface. Finally, different RPD components were modeled respectively and connected by minor connectors to form an integrated RPD framework. The finished data were imported into a self-developed selective laser melting (SLM) machine and metal frameworks were fabricated directly. RESULTS: RPD frameworks for the two scanned dental casts were modeled with this self-developed program and metal RPD frameworks were successfully fabricated using SLM method. The finished metal frameworks fit well on the plaster models. CONCLUSIONS: The self-developed computer aided design and computer aided manufacture (CAD-CAM) system for RPD design and fabrication has completely independent intellectual property rights. It provides a new method of manufacturing metal RPD frameworks.


Asunto(s)
Diseño Asistido por Computadora , Dentadura Parcial Removible , Humanos , Rayos Láser , Programas Informáticos
12.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 45(10): 631-4, 2010 Oct.
Artículo en Chino | MEDLINE | ID: mdl-21176603

RESUMEN

OBJECTIVE: To establish the computer aided design (CAD) software platform of individualized abutment for the maxilla central incisor. METHODS: Three-dimentional data of the incisor was collected by scanning and geometric transformation. Data mainly included the occlusal part of the healing abutment, the location carinae of the bedpiece, the occlusal 1/3 part of the artificial gingiva's inner surface, and so on. The all-ceramic crown designed in advanced was "virtual cutback" to get the original data of the abutment's supragingival part. The abutment's in-gum part was designed to simulate the individual natural tooth root. The functions such as "data offset", "bi-rail sweep surface" and "loft surface" were used in the process of CAD. RESULTS: The CAD route of the individualized all-ceramic abutment was set up. The functions and application methods were decided and the complete CAD process was realized. CONCLUSIONS: The software platform was basically set up according to the requests of the dental clinic.


Asunto(s)
Cerámica , Diseño Asistido por Computadora , Diseño de Prótesis Dental , Coronas , Implantes Dentales , Porcelana Dental , Humanos , Incisivo , Maxilar
13.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 44(2): 117-20, 2009 Feb.
Artículo en Chino | MEDLINE | ID: mdl-19563048

RESUMEN

OBJECTIVES: To develop a mathematical algorithm and a software package for the process of electronically surveying a scanned point cloud cast. To provide a principal premise to the subsequent computer aided design and computer aided manufacture (CAD/CAM) of removable partial denture framework, and to provide a method to improve quality control in the dental laboratory. METHODS: Point cloud data of a partially edentulous cast, a mandibular Kennedy Class II Modification 2 arch, was captured using an optical scanning system with projective grating and high-resolution digital camera. Using commercial CAD/CAM software system (Geomagic Studio 6), this point cloud data was processed and the 3-D digital model of partially edentulous cast was reconstructed. From a suggested surveying angle the contour points of height were identified, and then the digital surveying lines were traced using Projection and Contour Extraction software package. The depth of undercut was measured and defined to determine the clasp termination of retainer. RESULTS: Electronic surveying line of 3-D digital dentition defect model was achieved. Digital surveying line defined the cast into undercut and non-undercut areas. Different virtualized paths of insertion could be automatically suggested when the cast was surveyed and analyzed from different angles. The depth of undercut was automatically measured and the retentive clasp termination was determined. CONCLUSIONS: The mathematical algorithm and the software package in this study can be used to survey and analyze 3-D digital models of dentition defects, and to identify an electronic surveying line.


Asunto(s)
Diseño Asistido por Computadora , Modelos Dentales , Dentadura Parcial Removible , Algoritmos , Dentición , Imagenología Tridimensional , Programas Informáticos
14.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 44(1): 46-9, 2009 Jan.
Artículo en Chino | MEDLINE | ID: mdl-19489260

RESUMEN

OBJECTIVE: To examine the shear and microtensile bond strength between a newly developed dental machinable composite resin (polymethylmetacrylate/nano SiO2-ZrO2, PNSZ) and dentin cemented using three resin luting systems and to select the most suitable one. METHODS: The shear and microtensile bond strength between the machinable composite resin and dentin cemented using three resin luting systems (Group A:RelyX ARC, Group B:Panavia-F,Group C:Variolink II) were tested. The broken specimens were observed with a stereomicroscope (x 50) to compare their failure modes. RESULTS; In the shear tests, no significant difference was found in bond strength among Group A [ (14. 07 +/- 4. 67) MPa] ,Group B[ (13.17 +/- 4. 63) MPa] and Group C [ ( 12. 10 +/- 2.18) MPa] (P > 0.05) . In the microtensile tests, no significant difference was found in bond strength among Group A [(11.49 +/- 4.90) MPa],Group B[(9.66 +/- 4.15) MPa].and Group C[(10.11 +/- 4.20) MPa](P > 0. 05).The failure modes of all the three resin cements were predominantly adhesive failures at the dentin/cement interface. CONCLUSIONS: The three types of resin cements showed similar results in bond strength between the dental machinable composite resin and dentin. Bonding at the resin/cement interface was stronger than that at the dentin/cement interface.


Asunto(s)
Dentina , Cementos de Resina , Resistencia al Corte , Resinas Acrílicas , Resinas Compuestas , Recubrimiento Dental Adhesivo , Porcelana Dental , Análisis del Estrés Dental , Humanos , Poliuretanos
15.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 44(10): 629-33, 2009 Oct.
Artículo en Chino | MEDLINE | ID: mdl-20079313

RESUMEN

OBJECTIVE: To develop a method of three-dimensional computer aided design (CAD) of post-and-core restoration. METHODS: Two plaster casts with extracted natural teeth were used in this study. The extracted teeth were prepared and scanned using tomography method to obtain three-dimensional digitalized models. According to the basic rules of post-and-core design, posts, cores and cavity surfaces of the teeth were designed using the tools for processing point clouds, curves and surfaces on the forward engineering software of Tanglong prosthodontic system. Then three-dimensional figures of the final restorations were corrected according to the configurations of anterior teeth, premolars and molars respectively. RESULTS: Computer aided design of 14 post-and-core restorations were finished, and good fitness between the restoration and the three-dimensional digital models were obtained. Appropriate retention forms and enough spaces for the full crown restorations can be obtained through this method. CONCLUSIONS: The CAD of three-dimensional figures of the post-and-core restorations can fulfill clinical requirements. Therefore they can be used in computer-aided manufacture (CAM) of post-and-core restorations.


Asunto(s)
Diseño Asistido por Computadora , Técnica de Perno Muñón , Diseño de Prótesis Dental/métodos , Humanos
16.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 44(12): 763-6, 2009 Dec.
Artículo en Chino | MEDLINE | ID: mdl-20193297

RESUMEN

OBJECTIVE: To develop a method of surveying the digitalized partially dentate cast in order to accomplish computer aided design (CAD) of removable partial denture (RPD) frameworks. METHODS: The stone cast of a partially dentate patient was scanned using a three-dimensional laser scanner. Points on the surface of the digitalized cast, termed as a "point cloud", were obtained. The point cloud was then imported into self-developed Tanglong software to sample and uniform. New module of identifying the surveying lines was specially written in Tanglong using C++. A straight line was created in the center of the cloud point. Then the cloud point surrounding the straight line was divided into many parts. Local coordinates were established to indicate the information of angle and distance of every point to the straight line. Surveying lines were produced step by step electronically by identifying the closest and farthest points relative to the straight line and then connected together. Different surveying lines were obtained by adjusting the angle of the straight line. After the surveying lines were decided, the undercut areas could be marked and the depth of undercut was calculated automatically. The blockout of the undercuts could also be achieved by moving the location of the point cloud in undercut area. RESULTS: Survey lines of digitalized partially dentate casts were generated in computer. The undercut area and its depth were identified and the undercut could be blocked out. The shape of survey lines on the digitalized casts was similar to that on the physical casts drawn using traditional method. CONCLUSIONS: The new module in Tanglong software was developed specifically for surveying partially dentate casts. It had a user-friendly interface with the easy-to-understand menus. The success of surveying dental casts digitally would make it possible to CAD of RPD frameworks.


Asunto(s)
Diseño Asistido por Computadora , Modelos Dentales , Dentadura Parcial Removible , Programas Informáticos , Humanos
17.
Beijing Da Xue Xue Bao Yi Xue Ban ; 40(6): 654-7, 2008 Dec 18.
Artículo en Chino | MEDLINE | ID: mdl-19088843

RESUMEN

The concept of computer-aided design/computer aided manufacturing (CAD/CAM) was first mentioned decades ago in the field of dentistry. The technology to make dental restorations has found wide application recently and developed rapidly in prosthodontics and oral implantology, for it could save patients' time and manpower, have precision on prostheses' edging, etc. Until now there are several commercial CAD/CAM systems on market. With the use of CAD/CAM technology in dentistry, it has broken the traditional pattern of making dentures manually. Meanwhile, it brings opportunity for material science. The machinable/milled materials in dentistry should have not only excellent biocompatibility, but also machining and physical properties. Both of them are important. Nowadays, a great number of blocks are made from feldspar ceramics, glass-ceramics, alumina oxide, zirconium oxide, titanium, composite materials, wax and so on. Lots of researchers have had their focus on metal-free materials, because it can make the restorations look more natural and not show the inside metal color. However, strength like feldspar ceramics has its own disadvantages. It has strict indications, otherwise the restoration may fail. The technique called In-Ceram has been used long time ago. It also has long clinical experience and excellent long-term prognosis. People have explored this technique in CAD/CAM restorations. Studies have manifested that it can be utilized this way. At first, alumina was milled with pores; then, glass was infiltrated to the milled material. After zirconia had its success used in orthopedics, it became more and more popular to investigate whether this stuff was suitable in dentistry or not. Luckily, it has been proved adaptable for making single crown in posterior area, fixed partial dentures, in particular, and milling it using CAM equipment, due to the partially sintered block's hardness like chalk. Several milled polymer materials are made for temporary crowns or bridges. In recent years, because of the phenomenon about microleakage of the direct filling composite resin intraoral, indirect filling method, inlay, by the adhesive agent has bonded the tooth tissue and the material to eliminate the microleakage. It is the chemical bonding. As a result of this, maybe composite material made inlay will be prospective. As the aging phenomenon of the polymers are inevitable, and the resin matrix are polymers, it is not suitable for cosmetic restorations. Metal materials for CAD/CAM have some commercial products. But few scholars do the studies about it. In this article you will find that many investigators abroad do the research about the commercial blocks on their physical and clinical study. On the other hand, domestic scholars pay attention to the basis of the material research. It provides the overview of the materials for CAD/CAM in dentistry.


Asunto(s)
Diseño Asistido por Computadora , Materiales Dentales , Cerámica/química , Resinas Compuestas/química , Diseño de Prótesis Dental , Humanos , Circonio/química
18.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 43(12): 748-51, 2008 Dec.
Artículo en Chino | MEDLINE | ID: mdl-19134353

RESUMEN

OBJECTIVE: To compare the microstructure and mechanical properties of pure titanium specimens fabricated using laser melted rapidly solidified forming (LMRSF) and casting, and to provide scientific evidence for the new method of laser rapid forming in prosthodontic field. METHODS: Six pure titanium specimens were fabricated from pure titanium powder using LMRSF technology, and six pure titanium casting specimens were used as the controls. The tensile strength was measured and the microstructures and natural fracture surface of the pure titanium specimens made in two different ways were observed. RESULTS: Compared to that in the casting specimen, the microstructure of the LMRSF titanium specimens was denser and acicular structure distributed more uniformly. The tensile strength and the microhardness of the pure titanium specimens were (510.0 +/- 21.2) MPa and (201.4 +/- 14.5) MPa respectively, which were much higher than those of the dental pure titanium castings [(425.0 +/- 35.1) MPa and (186.5 +/- 9.5) MPa] (P < 0.01). CONCLUSIONS: The microstructure and mechanical properties of the pure titanium specimens fabricated using LMRSF are better than that of the pure titanium castings. Therefore, the LMRSF will provide titanium framework with better quality for removable dental restoration.


Asunto(s)
Materiales Dentales , Rayos Láser , Titanio/química , Técnica de Colado Dental , Análisis del Estrés Dental , Dureza , Ensayo de Materiales
20.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 42(6): 324-9, 2007 Jun.
Artículo en Chino | MEDLINE | ID: mdl-17888244

RESUMEN

OBJECTIVE: To explore a computer aided design (CAD) and rapid prototyping (RP) approach for fabrication of complete denture and to develop relevant programs for implementing it. METHODS: Automatic crossing section scanner was used to scan artificial teeth and 3D graphic database of artificial teeth that could be aligned with parameters was established. A 3D laser scanner was used to scan upper and lower edentulous jaw casts and rims made in clinic. The vertical and horizontal relations were recorded before scanning with a patient instrument. Based on Imageware 11, tooth-arrangement curves, coordinate system, and landmark points for positioning were created, and construction cure and shape-controlling curve for base plate were constructed as well. Three-dimensional integrated design of complete denture, including artificial tooth automatic arrangement, aesthetic and individualized design of base plate, and artificial gingival, were finished. The programs were developed following the approach and the CAD platform was established. The virtual molds of complete dentures were constructed according to the above data in design and RP technology was used to make the plaster molds. Finally, the teeth were inserted and the complete denture was finished by dental technician. RESULTS: The approach for the complete denture CAD/RP was confirmed and the CAD software platform was developed. A complete denture was manufactured. CONCLUSIONS: The rules for complete denture in textbooks were expressed in design process with the CAD program developed by researcher. The 3D data of rims were utilized in design so that the digital, intelligentized and individualized design and manufacture process for complete denture was implemented.


Asunto(s)
Diseño Asistido por Computadora , Dentadura Completa , Humanos , Diseño de Software
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...