Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 243
Filtrar
1.
Prim Dent J ; 8(3): 34-39, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31666171

RESUMO

AIM: The purpose of the present study was to assess the accuracy of intra-oral scans and conventional impression measured at various points on a single tooth preparation. METHODS: Ten conventional silicone impressions, and ten intra oral-scans using eight different digital intra oral digital scanners were taken of a prepared master tooth. The conventional impressions were directly digitised using a laboratory scanner. Each scan/impression was superimposed on a high-accuracy digital model of the prepared master tooth. For each superimposition, the deviation from the prepared master tooth was measured at six points on four two-dimensional cross-sections. Data was analysed using two-way analysis of variance (ANOVA). RESULTS: Most intra oral scanners had lower accuracy at the preparation margin compared to smooth surfaces. When only conventional impression and the latest intra oral scanners of various manufacturers are considered, the mean discrepancy at the preparation margin was 50µm (SD 16) for conventional impression, 15µm (SD 4) for trios 3, 26µm (SD 4) for LAVA TDS, 29µm (SD 7) for CEREC Omnicam, 30µm (SD 6) for CS 3600 and 64µm (SD 7) for GC aadva. The increased accuracy of trios 3 was statistically significant (p<0.05). CONCLUSIONS: At the preparation margin, Trios 3 performed significantly better than conventional impression and the other intra oral scanners. LAVA TDS, CEREC Omnicam and CS3600 showed similar accuracy at the margin, yet better than conventional impression and GC Aadva.


Assuntos
Desenho Assistido por Computador , Confiabilidade dos Dados , Técnica de Moldagem Odontológica/instrumentação , Dente Pré-Molar/diagnóstico por imagem , Materiais para Moldagem Odontológica , Técnica de Moldagem Odontológica/normas , Humanos , Imageamento Tridimensional , Incisivo/diagnóstico por imagem , Dente
2.
J Vis Exp ; (147)2019 05 30.
Artigo em Inglês | MEDLINE | ID: mdl-31205295

RESUMO

Digital workflows have actively been used to produce dental restorations or oral appliances since dentists started to make digital impressions by acquiring 3D images with an intraoral scanner. Because of the nature of scanning the oral cavity in the patient's mouth, the intraoral scanner is a handheld device with a small optical window, stitching together small data to complete the entire image. During the complete-arch impression procedure, a deformation of the impression body can occur and affect the fit of the restoration or appliance. In order to measure these distortions, a master specimen was designed and produced with a metal 3D printer. Designed reference geometries allow setting independent coordinate systems for each impression and measure x, y, and z displacements of the cylinder top circle center where the distortion of the impression can be evaluated. In order to evaluate the reliability of this method, the coordinate values of the cylinder are calculated and compared between the original computer-aided design (CAD) data and the reference data acquired with the industrial scanner. The coordinate differences between the two groups were mostly less than 50 µm, but the deviations were high due to the tolerance of 3D printing in the z coordinates of the obliquely designed cylinder on the molar. However, since the printed model sets a new standard, it does not affect the results of the test evaluation. The reproducibility of the reference scanner is 11.0 ± 1.8 µm. This test method can be used to identify and improve upon the intrinsic problems of an intraoral scanner or to establish a scanning strategy by measuring the degree of distortion at each part of the complete-arch digital impression.


Assuntos
Arco Dental/fisiologia , Técnica de Moldagem Odontológica/normas , Modelos Dentários/normas , Imageamento Tridimensional/métodos , Humanos
3.
Artigo em Inglês | MEDLINE | ID: mdl-30897832

RESUMO

The aim of this study was to two-dimensionally evaluate deviation errors at five digital cross-sections of single-tooth abutment in regards to data obtained from two intraoral scanners, and to evaluate accuracy of individual scanners. Two intraoral scanners, the Trios 3® (3 Shape, Copenhagen, Denmark) and EzScan® (Vatech, Hwaseong, Korea), were evaluated by utilizing 13 stone models. The superimposed 3D data files were sectioned into five different planes: buccal-lingual section (BL), mesial-distal section (MD), transverse high section (TH), transverse middle section (TM), and transverse low section (TL). Accuracy comparison between the two scanners in 5 groups was performed. BL vs. MD of each scanner, and three transverse groups (TH, TM, TL) of each scanner were analyzed for accuracy comparison. In comparison of 2-D analyses for two intraoral scanners, Trios 3® showed statistically significant higher accuracy in root mean square (RMS) at BL, TH, and TL (p < 0.05). For each scanner, RMS value showed that mesial-distal sections were more prone to error than buccal-lingual section, which exhibited statistically significant errors (p < 0.05) while the transverse groups did not. Two-dimensional analysis is more insightful than three-dimensional analysis on single-tooth abutment. In mesiodistal areas, rough prepped areas, and sharp edges where scanner accessibility is difficult, high deviation errors are shown.


Assuntos
Desenho Assistido por Computador/instrumentação , Técnica de Moldagem Odontológica/instrumentação , Dente , Adulto , Desenho Assistido por Computador/normas , Técnica de Moldagem Odontológica/normas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes
4.
Dent Med Probl ; 56(1): 67-74, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30888119

RESUMO

BACKGROUND: The dimensional accuracy of impression materials has been evaluated for a long time, but thus far, digital radiography has not been used for this purpose. The dimensional accuracy of impression materials is very important for the final adaptation of dental prostheses. OBJECTIVES: The objective of this study was to evaluate the effects of different disinfectant solutions and storage times on the dimensional stability of different impression materials by means of digital radiography. MATERIAL AND METHODS: Polyether (PE), hydrocolloid (IH), condensation silicone (CS), and addition silicone (AS) materials were used for preparing impressions, taken from an acrylic master model with 2 vertical and 2 horizontal reference points. Water (W), sodium hypochlorite (SH) and a disinfectant solution without aldehyde (Z) were applied on the impressions. Half of the impressions were poured over immediately and half of them - 1 day after. Digital radiography was used to determine the dimensional accuracy of the impression materials. The data was analyzed with a variance analysis and Tukey's multiple comparison test. RESULTS: While PE showed the smallest dimensional changes, IH showed the greatest in all lines. Applying SH and pouring 1 day after caused the greatest dimensional changes in all impression materials. CONCLUSIONS: Different disinfectant solutions and storage times had a different effect on the impressions, but the dimensional changes were clinically acceptable.


Assuntos
Materiais para Moldagem Odontológica , Técnica de Moldagem Odontológica , Desinfetantes , Radiografia Dentária Digital , Materiais para Moldagem Odontológica/normas , Técnica de Moldagem Odontológica/normas , Desinfetantes/farmacologia , Radiografia Dentária Digital/normas , Propriedades de Superfície/efeitos dos fármacos , Fatores de Tempo
5.
Artigo em Inglês | MEDLINE | ID: mdl-30769768

RESUMO

The aim of this in vitro study was to compare the quality of digital workflows generated by different scanners (Intra-oral digital scanners (I.O.S.s)) focusing on marginal fit analysis. A customized chrome-cobalt (Cr-Co) implant abutment simulating a maxillary right first molar was fixed in hemi-maxillary stone model and scanned by eight different I.O.S.s: Omnicam® (Denstply Sirona, Verona, Italy) CS3500®, CS3600®, (Carestream Dental, Atlanta, GA, USA), True Definition Scanner® (3M, St. Paul, MN, USA), DWIO® (Dental Wings, Montreal, Quebec, Canada), PlanScan® (Planmeca Oy, Helsinki, Finland), 3D PROGRESS Plus® (MHT, Verona, Italy), TRIOS 3® (3Shape, Copenhagen, Denmark). Nine scans were performed by each tested I.O.S. and 72 copings were designed using a dental computer-assisted-design/computer-assisted-manufacturing (CAD/CAM) software (exocad GmbH, Darmstadt, Germany). According to CAD data, zirconium dioxide (ZrO2) copings were digitally milled (Roland DWX-50, Irvine, CA, USA). Scanning electron microscope (SEM) direct vision allowed for marginal gap measurements in eight points for each specimen. Descriptive analysis was performed using mean, standard deviation, and median, while the Kruskal⁻Wallis test was performed to determine whether the marginal discrepancies were significantly different between each group (significance level p < 0.05). The overall mean marginal gap value and standard deviation were 53.45 ± 30.52 µm. The minimum mean value (40.04 ± 18.90 µm) was recorded by PlanScan®, then 3D PROGRESS Plus® (40.20 ± 21.91 µm), True Definition Scanner® (40.82 ± 26.19 µm), CS3500® (54.82 ± 28.86 µm) CS3600® (59,67 ± 28.72 µm), Omnicam® (61.57 ± 38.59 µm), DWIO® (62.49 ± 31.54 µm), while the maximum mean value (67.95 ± 30.41 µm) was recorded by TRIOS 3®. The Kruskal⁻Wallis tests revealed a statistically significant difference (p-value < 0.5) in the mean marginal gaps between copings produced by 3D PROGRESS Plus®, PlanScan, True Definition Scanner, and the other evaluated I.O.S.s. The use of an I.O.S. for digital impressions may be a viable alternative to analog techniques. Although in this in vitro study PlanScan®, 3D PROGRESS Plus® and True Definition Scanner® may have showed the best performances, all I.O.S.s tested could provide clinically encouraging results especially in terms of marginal accuracy, since mean marginal gap values were all within the clinically acceptable threshold of 120 µm.


Assuntos
Desenho Assistido por Computador , Coroas/normas , Técnica de Moldagem Odontológica/normas , Adaptação Marginal Dentária/normas , Planejamento de Prótese Dentária/normas , Dente/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Canadá , Dinamarca , Feminino , Finlândia , Alemanha , Humanos , Itália , Masculino , Pessoa de Meia-Idade , Quebeque
6.
Clin Anat ; 32(3): 430-438, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30663815

RESUMO

The aim of this study was to evaluate the factors affecting intra-oral scanner accuracy by analyzing variation in measurements of a dental model according to scanning distance. A dental cast, including a prepared left mandibular first molar, was used. Rectangular frames measuring 20 × 30 mm with heights of 2.5, 5.0, and 7.5 mm were made. The model was scanned 10 times with a reference scanner to obtain the true value. Scanning was performed 10 times at four distances of 0, 2.5, 5.0, and 7.5 mm with the frame of each height using the following intra-oral scanners: TRIOS; CS 3500; and PlanScan. In the linear distance measurement method (2D), measurements were taken at five parameters using the Rapidform software. In the best-fit alignment method (3D), using the Geomagic Control X, the root mean square values of the two scan images were calculated. In the 2D comparison, the different from the reference value was the smallest at 2.5 and 5.0 mm. In the 3D comparison, 2.5 and 5.0 mm were the most accurate, and 0 mm was the least accurate among the four distances. To the best of our knowledge, this study was the first to evaluate the accuracy of scanning distances, and found a difference between the accuracy of the scanning distance and the accuracy of the scanner. Moreover, the results of this study indicated that the scanning distance was a variable affecting accuracy. Clin. Anat. 32:430-438, 2019. © 2019 Wiley Periodicals, Inc.


Assuntos
Precisão da Medição Dimensional , Processamento de Imagem Assistida por Computador/normas , Imageamento Tridimensional/normas , Desenho Assistido por Computador/normas , Técnica de Moldagem Odontológica/normas , Modelos Dentários , Humanos , Processamento de Imagem Assistida por Computador/instrumentação , Imageamento Tridimensional/instrumentação , Dente/diagnóstico por imagem
7.
Artigo em Inglês | MEDLINE | ID: mdl-31888225

RESUMO

AIMS: The study aims to assess the accuracy of digital planning in dentistry, evaluating the characteristics of different intraoral 3D scanners and comparing it with traditional imaging 2D recording methods. Specifically, using computer aided design (CAD) software and measuring inside CAD software, authors want to verify the reliability of different models obtained with different techniques and machines. METHODS: 12 patients that needed aesthetic restorative treatment were enrolled in the study. All the patients underwent recording data of the height and width dental elements 1.1, 1.2, and 1.3 size using different technologies and comparing 2D with 3D methods. A T test was then applied in order to verify whether there was a statistically significant difference between the measurements obtained, comparing the different tools data (Emerald, TRIOS, Photogrammetry and DSS (Digital Smile System)) with the reference values. RESULTS: No significant differences emerged in the measurements made with the different scanners (Trios 3Shape ®, Planmeca Emerald ®) and photogrammetry. Therefore, what should be underlined regarding the 2D measurements is the speed and simplicity compared to all 3D techniques, so this work can help to better define the field of application and the limits connected to 2D techniques, giving a good window of the technique. CONCLUSIONS: The low number of patients is not sufficient to provide statistically significant results, but the digital planning future prospects seem to be promising. This study results highlighted how a photogrammetric scanner for dental arches would only have a much smaller shooting field size and greater accuracy. Despite these considerations, the photogrammetric facial scanner provided excellent results for the measurement of individual teeth, showing a great versatility of use.


Assuntos
Desenho Assistido por Computador/normas , Arco Dental/diagnóstico por imagem , Técnica de Moldagem Odontológica/normas , Imageamento Tridimensional/normas , Fotografia Dentária/normas , Prostodontia/métodos , Realidade Virtual , Humanos , Reprodutibilidade dos Testes , Software/normas
8.
São José dos Campos; s.n; 2019. 98 p. il., tab., graf..
Tese em Português | BBO - Odontologia | ID: biblio-1024928

RESUMO

A otimização do tempo reabilitador é um benefício direto a saúde do paciente, pois previne o mesmo do contato com possíveis contaminações e ambientes que lhe causem estresse. Isso pode ser viabilizado pelo desenvolvimento de técnicas que diminuam etapas de execução de um determinado tratamento. Pensando nisso, esse trabalho tem por objetivo avaliar a desadaptação marginal de copings em liga de cobalto-cromo (Co-Cr) através da técnica da réplica de silicone (2D) e avaliação por varredura digital (3D), em 24 dentes humanos unirradiculares, com retentores intraradiculares (RIR) em Co-Cr, cimentados com cimento de fosfato de zinco. Divididos em dois grupos, ambos com término marginal em ombro 130º: grupo A obtidos pelo método convencional, com execução de RIR primeiro, para depois coping com retentor já cimentado e grupo B de moldagem única para obtenção de RIR e coping. Os resultados foram submetidos a uma análise do teste t e de variância ANOVA. A técnica da réplica de silicone, demonstrou as seguintes médias de valores marginais: 83,77±51,84µm (grupo A) e 77,09±31,65µm (grupo B) p=0,4477 E a varredura digital, os resultados positivos revelaram que as médias de todas as superfícies encontraram-se acima de 50 µm; e os negativos: revelaram que as médias encontraram-se abaixo de 100 µm. Este estudo concluiu que é possível obter RIR e coping através de moldagem única(AU)


The optimization of the clinical appointment is a direct benefit to the health of the patient, because prevents it from the contact with possible contaminations and environments that cause stress. This can be possible by the development of techniques that may decrease the execution stages of a treatment. With this in mind, the aims of this study is to investigate the marginal adaptation of CobaltChromium alloy (Co-Cr) copings through silicone replica technique (2D) and digital evaluation (3D) in 24 human single rooted teeth with post-and-core in Co-Cr, cemented with zinc phosphate. Divided in to two groups, both having shoulder 130 degrees as marginal type: group A by the conventional method, impression and cementation of Co-Cr post-and-core first and then impression for the coping and group B single impression for coping and post and core. The results were analyzed by test t and one-way ANOVA. The silicone replica technique showed the following mean marginal values: 83.77 ± 51.84 µm (group A) and 77.09 ± 31, 65 µm (group B) p= 0,4477. The digital protocol, in the positive results revealed that the averages of all surfaces were above 50 µm; and the negatives: revealed that the averages were below 100 µm. This study concluded that it is possible to obtain post-and-core and coping through a single impression technique(AU)


Assuntos
Humanos , Adaptação Marginal Dentária , Técnica de Moldagem Odontológica/normas , Prótese Dentária/efeitos adversos
9.
Niger J Clin Pract ; 21(10): 1247-1253, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30297554

RESUMO

Aims: The aim of this study was to compare the dimensional accuracy of four different implant impression techniques of a mandibular edentulous model with five parallel implants. Materials and Methods: Five dental implants were placed in an edentulous mandibular model in parallel. A total of forty impressions were obtained using four different impression techniques. In Group 1 (G1) and Group 2 (G2), closed tray impressions with and without plastic caps, respectively, were used. In Group 3 (G3) and Group 4 (G4), open tray impressions with a direct splinted technique and an improved direct splinted technique, respectively, were used. All the impressions were poured with Type IV dental stone. Master model and study casts were scanned with a laser optical scanner and aligned by observing the superpositions of the anatomical landmarks using a software program. Statistical Analysis Used: Fifty measurements of the apical, coronal, and angular discrepancies of the master and study casts were obtained (n = 50) and statistically analyzed using a one-way analysis of variance and post hoc (least significant difference ) and Friedman's tests. Results: The lowest accuracy was obtained from G2 when the angular (1.48°), coronal (0.32 µm), and apical (0.14 µm) deviations were tested (P < 0.05), whereas no statistically significant differences were found among the other groups (P < 0.05). Conclusions: In cases with five parallel mandibular implants, improved accuracy was achieved using the direct splinted technique, the improved direct splinted technique, or the closed tray impression technique with snap on plastic caps.


Assuntos
Implantes Dentários , Materiais para Moldagem Odontológica/normas , Técnica de Moldagem Odontológica/normas , Técnica de Moldagem Odontológica/instrumentação , Materiais Dentários , Modelos Dentários , Humanos , Mandíbula
10.
BMC Oral Health ; 18(1): 117, 2018 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-29970056

RESUMO

BACKGROUND: Intraoral scanners are devices for capturing digital impressions in dentistry. Until now, several in vitro studies have assessed the trueness of digital impressions, but in vivo studies are missing. Therefore, the purpose of this study was to introduce a new method to assess trueness of intraoral scanners and digital impressions in an in vivo clinical set-up. METHODS: A digital impression using an intraoral scanner (Trios® 3 Cart wired, 3Shape, Copenhagen, Denmark) and a conventional alginate impression (Cavex Impressional®, Cavex, Haarlem, the Netherlands) as clinical reference were made for two patients assigned for full mouth extraction. A total of 30 teeth were collected upon surgery after impressions making. The gypsum model created from conventional impression and extracted teeth were then scanned in a lab scanner (Activity 885®, SmartOptics, Bochum, Germany). Digital model of the intraoral scanner (DM), digital model of the conventional gypsum cast (CM) and those of the extracted natural teeth (NT) were imported to a reverse engineering software (3-matic®, Materialise, Leuven, Belgium) in which the three models were registered then DM and CM were compared to their corresponding teeth in NT by distance map calculations. RESULTS: DM had statistically insignificant better trueness when compared to CM for total dataset (p = 0.15), statistically insignificant better trueness for CM when mandibular arches analyzed alone (p = 0.56), while a significantly better DM trueness (p = 0.013) was found when only maxillary arches were compared. CONCLUSIONS: Our results show that digital impression technique is clinically as good as or better than the current reference standard for study models of orthognathic surgery patients.


Assuntos
Técnica de Moldagem Odontológica , Técnica de Moldagem Odontológica/normas , Humanos , Imageamento Tridimensional/métodos , Imageamento Tridimensional/normas , Mandíbula/diagnóstico por imagem , Maxila/diagnóstico por imagem , Reprodutibilidade dos Testes , Dente/diagnóstico por imagem
11.
J Prosthet Dent ; 120(3): 389-395, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29703675

RESUMO

STATEMENT OF PROBLEM: Although computer-aided design and computer-aided manufacturing (CAD-CAM) complete removable dental prostheses (CRDPs) have gained popularity, conventional impressions are still common for CAD-CAM CRDP treatment. These need to be digitized and converted into virtual edentulous casts with a laboratory impression scan protocol during prosthesis fabrication. How this can best be accomplished is unclear. PURPOSE: The purpose of this in vitro study was to compare the accuracy and reproducibility of virtual edentulous casts created by a dental laboratory laser scanner and a cone beam computed tomography (CBCT) scanner with a digitized master cast. MATERIAL AND METHODS: A master cast was digitized as the virtual reference cast. Ten polyvinyl siloxane impressions were made on the master cast and scanned with the dental laboratory laser scanner and CBCT scanner. The impressions were sprayed with antiglare spray and rescanned. Four groups of virtual study casts (N=40) were created from the impression scans. All virtual study casts and the reference cast were registered with surface-matching software, and the root mean square (RMS) values (representation of overall accuracy) and percentage of measurement data points within 1 standard deviation (SD) of mean RMS values (%, representation of overall reproducibility) among the 4 study groups were measured. Additionally, 95 numeric distance differences (representation of accuracy at each region) were measured in 5 distinct regions: the apex of the denture border, 6 mm from denture border, crest of the ridge, palate, and posterior palatal seal. The repeated-measures ANOVA and post hoc test (t grouping) were used to determine statistical differences (α=.05). RESULTS: The laboratory scanner group had a significantly larger RMS value (4.0 ±0.3 µm, P<.001) and smaller percentage of measurement data points within 1 SD of mean RMS value (77.5 ±1.0%, P<.001). The RMS values between the CBCT scanner (1.2 ±0.3 µm) and CBCT scanner-spray (1.1 ±0.2 µm) groups were not significantly different (P=.968), and the percentage of measurement data points within 1 SD of mean RMS values (90.1 ±1.1% versus 89.5 ±0.8%) were also not significantly different (P=.662). The numeric distance differences across 5 regions were affected by the scanning protocols (P<.001). The laboratory scanner and laboratory scanner-spray groups had significantly higher numeric distance differences at the apex of the denture border and crest of the ridge regions (P<.001). CONCLUSIONS: The CBCT scanner created more accurate and reproducible virtual edentulous casts, and the antiglare spray only significantly improved the accuracy and reproducibility of virtual edentulous casts created by the dental laboratory laser scanner. The accuracy of the virtual edentulous casts was different across 5 regions and was affected by the scanning protocols.


Assuntos
Técnica de Fundição Odontológica , Técnica de Moldagem Odontológica , Planejamento de Dentadura/métodos , Prótese Total , Desenho Assistido por Computador/normas , Tomografia Computadorizada de Feixe Cônico , Técnica de Fundição Odontológica/normas , Técnica de Moldagem Odontológica/normas , Planejamento de Dentadura/normas , Prótese Total/normas , Humanos , Reprodutibilidade dos Testes
12.
BMC Oral Health ; 18(1): 27, 2018 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-29471825

RESUMO

BACKGROUND: Several studies have evaluated accuracy of intraoral scanners (IOS), but data is lacking regarding variations between IOS systems in the depiction of the critical finish line and the finish line accuracy. The aim of this study was to analyze the level of finish line distinctness (FLD), and finish line accuracy (FLA), in 7 intraoral scanners (IOS) and one conventional impression (IMPR). Furthermore, to assess parameters of resolution, tessellation, topography, and color. METHODS: A dental model with a crown preparation including supra and subgingival finish line was reference-scanned with an industrial scanner (ATOS), and scanned with seven IOS: 3M, CS3500 and CS3600, DWIO, Omnicam, Planscan and Trios. An IMPR was taken and poured, and the model was scanned with a laboratory scanner. The ATOS scan was cropped at finish line and best-fit aligned for 3D Compare Analysis (Geomagic). Accuracy was visualized, and descriptive analysis was performed. RESULTS: All IOS, except Planscan, had comparable overall accuracy, however, FLD and FLA varied substantially. Trios presented the highest FLD, and with CS3600, the highest FLA. 3M, and DWIO had low overall FLD and low FLA in subgingival areas, whilst Planscan had overall low FLD and FLA, as well as lower general accuracy. IMPR presented high FLD, except in subgingival areas, and high FLA. Trios had the highest resolution by factor 1.6 to 3.1 among IOS, followed by IMPR, DWIO, Omnicam, CS3500, 3M, CS3600 and Planscan. Tessellation was found to be non-uniform except in 3M and DWIO. Topographic variation was found for 3M and Trios, with deviations below +/- 25 µm for Trios. Inclusion of color enhanced the identification of the finish line in Trios, Omnicam and CS3600, but not in Planscan. CONCLUSIONS: There were sizeable variations between IOS with both higher and lower FLD and FLA than IMPR. High FLD was more related to high localized finish line resolution and non-uniform tessellation, than to high overall resolution. Topography variations were low. Color improved finish line identification in some IOS. It is imperative that clinicians critically evaluate the digital impression, being aware of varying technical limitations among IOS, in particular when challenging subgingival conditions apply.


Assuntos
Técnica de Moldagem Odontológica , Desenho Assistido por Computador , Coroas , Técnica de Moldagem Odontológica/normas , Modelos Dentários , Planejamento de Prótese Dentária/métodos , Planejamento de Prótese Dentária/normas , Humanos , Imageamento Tridimensional , Técnicas In Vitro , Imagem Óptica/métodos , Reprodutibilidade dos Testes
13.
In. Gutiérrez Segura, Mildred. Prótesis estomatológica clínica. La Habana, Editorial Ciencias Médicas, 2018. , ilus.
Monografia em Espanhol | CUMED | ID: cum-70898
14.
Am J Orthod Dentofacial Orthop ; 152(3): 420-425, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28863923

RESUMO

INTRODUCTION: Our objectives were to evaluate and compare the digital dental models generated from 2 commercial intraoral scanners with manual measurements when performing 3-dimensional surface measurements along a curved line (curvilinear). METHODS: Dry mandibles (n = 61) with intact dentition were used. The mandibles were digitized using 2 chair-side intraoral scanners: Cadent iTero (Align Technology, San Jose, Calif) and Lythos Digital Impression system (Ormco, Orange, Calif). Digitized 3-dimensional models were converted to individual stereolithography files and used with commercial software to obtain the curvilinear measurements. Manual measurements were carried out directly on the mandibular teeth. Measurements were made on different locations on the dental arch in various directions. One-sample t tests and linear regression analyses were performed. To further graphically examine the accuracy between the different methods, Bland-Altman plots were computed. The level of significance was set at P <0.05. RESULTS: There were no significant differences between any of the paired methods; this indicated a certain level of agreement between the methods tested (P >0.05). Bland-Altman analysis showed no fixed bias of 1 approach vs the other, and random errors were detected in all comparisons. Although the mean biases of the digital models obtained by the iTero and Lythos scanners, when compared with direct caliper measurements, were low, the comparison of the 2 intraoral scanners yielded the lowest mean bias. No comparison displayed statistical significance for the t scores; this indicated the absence of proportional bias in these comparisons. CONCLUSIONS: The intraoral scanners tested in this study produced digital dental models that were comparatively accurate when performing direct surface measurements along a curved line in 3 dimensions.


Assuntos
Técnica de Moldagem Odontológica , Imageamento Tridimensional/métodos , Algoritmos , Arco Dental/anatomia & histologia , Arco Dental/diagnóstico por imagem , Técnica de Moldagem Odontológica/normas , Modelos Dentários , Humanos , Processamento de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/normas , Mandíbula/anatomia & histologia , Mandíbula/diagnóstico por imagem , Reprodutibilidade dos Testes , Dente/anatomia & histologia , Dente/diagnóstico por imagem
15.
J Am Dent Assoc ; 148(9): 654-660, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28601188

RESUMO

BACKGROUND: The authors evaluated and quantified clinically detectable errors commonly seen in impressions sent to commercial laboratories and determined possible relationships between finish line errors and other factors involved. METHODS: The authors visited 3 large and 1 small commercial dental laboratories over a 12-month period. Three calibrated examiners evaluated the impressions. The examiners evaluated all impressions for errors by using ×2.5 magnification loupes under ambient room lighting without the aid of additional illumination. RESULTS: The authors evaluated 1,157 impressions; 86% of the examined impressions had at least 1 detectable error, and 55% of the noted errors were critical errors pertaining to the finish line. The largest single error categories evaluated were tissue over the finish line (49.09%), lack of unprepared stops in dual-arch impressions (25.63%), pressure of the tray on the soft tissue (25.06%), and void at the finish line (24.38%). The factors blood on the impression (odds ratio, 2.31; P < .001) and tray type (odds ratio, 1.68; P < .001) were associated significantly with finish line errors. CONCLUSIONS: Marginal discrepancies made up the largest category of error noted in impressions evaluated. The authors noted an increase in errors at the finish line with dual-arch impression techniques and in the presence of blood. PRACTICAL IMPLICATIONS: Dentists have ethical, moral, and legal obligations bestowed on them by the profession and need to evaluate critically the work they send to laboratories. The authors strongly recommend an improvement in technique and reviewing of all impressions and working casts.


Assuntos
Coroas , Técnica de Moldagem Odontológica/normas , Coroas/normas , Prótese Parcial Fixa/normas , Humanos , Laboratórios Odontológicos/estatística & dados numéricos
16.
J Prosthet Dent ; 117(3): 410-418, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27677213

RESUMO

STATEMENT OF PROBLEM: Studies that evaluated the effect of dental technician disparities on the accuracy of presectioned and postsectioned definitive casts are lacking. PURPOSE: The purpose of this in vitro study was to evaluate the accuracy of presectioned and postsectioned definitive casts fabricated by different dental technicians by using a 3-dimensional computer-aided measurement method. MATERIAL AND METHODS: An arch-shaped metal master model consisting of 5 abutments resembling prepared mandibular incisors, canines, and first molars and with a 6-degree total angle of convergence was designed and fabricated by computer-aided design and computer-aided manufacturing (CAD-CAM) technology. Complete arch impressions were made (N=110) from the master model, using polyvinyl siloxane (PVS) and delivered to 11 dental technicians. Each technician fabricated 10 definitive casts with dental stone, and the obtained casts were numbered. All casts were sectioned, and removable dies were obtained. The master model and the presectioned and postsectioned definitive casts were digitized with an extraoral scanner, and the virtual master model and virtual presectioned and postsectioned definitive casts were obtained. All definitive casts were compared with the master model by using computer-aided measurements, and the 3-dimensional accuracy of the definitive casts was determined with best fit alignment and represented in color-coded maps. Differences were analyzed using univariate analyses of variance, and the Tukey honest significant differences post hoc tests were used for multiple comparisons (α=.05). RESULTS: The accuracy of presectioned and postsectioned definitive casts was significantly affected by dental technician disparities (P<.001). The largest dimensional changes were detected in the anterior abutments of both of the definitive casts. The changes mostly occurred in the mesiodistal dimension (P<.001). CONCLUSIONS: Within the limitations of this in vitro study, the accuracy of presectioned and postsectioned definitive casts is susceptible to dental technician differences.


Assuntos
Desenho Assistido por Computador , Técnica de Fundição Odontológica , Técnica de Moldagem Odontológica , Planejamento de Prótese Dentária/métodos , Técnicos em Prótese Dentária , Análise de Variância , Dente Suporte/normas , Materiais para Moldagem Odontológica/química , Técnica de Moldagem Odontológica/instrumentação , Técnica de Moldagem Odontológica/normas , Adaptação Marginal Dentária/normas , Modelos Dentários , Humanos , Imageamento Tridimensional , Mandíbula , Polivinil , Siloxanas
17.
J Dent Educ ; 80(10): 1229-1236, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27694297

RESUMO

Preclinical fixed prosthodontics is taught by Department of Prosthodontics faculty members at Virginia Commonwealth University School of Dentistry; however, 86% of all clinical cases in academic year 2012 were staffed by faculty members from the Department of General Practice. The aims of this retrospective study were to quantify the quality of impressions, accuracy of laboratory work authorizations, and most common errors and to determine if there were differences between the rate of errors in cases supervised by the prosthodontists and the general dentists. A total of 346 Fixed Prosthodontic Laboratory Tracking Sheets for the 2012 academic year were reviewed. The results showed that, overall, 73% of submitted impressions were acceptable at initial evaluation, 16% had to be poured first and re-evaluated for quality prior to pindexing, 7% had multiple impressions submitted for transfer dies, and 4% were rejected for poor quality. There were higher acceptance rates for impressions and work authorizations for cases staffed by prosthodontists than by general dentists, but the differences were not statistically significant (p=0.0584 and p=0.0666, respectively). Regarding the work authorizations, 43% overall did not provide sufficient information or had technical errors that delayed prosthesis fabrication. The most common errors were incorrect mountings, absence of solid casts, inadequate description of margins for porcelain fused to metal crowns, inaccurate die trimming, and margin marking. The percentages of errors in cases supervised by general dentists and prosthodontists were similar for 17 of the 18 types of errors identified; only for margin description was the percentage of errors statistically significantly higher for general dentist-supervised than prosthodontist-supervised cases. These results highlighted the ongoing need for faculty development and calibration to ensure students receive the highest quality education from all faculty members teaching fixed prosthodontics.


Assuntos
Técnica de Moldagem Odontológica/normas , Educação em Odontologia , Prostodontia/educação , Odontologia , Controle de Qualidade , Estudos Retrospectivos
18.
Int J Prosthodont ; 29(5): 467-72, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27611750

RESUMO

A model with simulated flabby tissue was fabricated by modifying the standard maxillary edentulous acrylic resin cast to evaluate the effect of maxillary impression tray design on the displacement of flabby tissue. Seven groups of trays were fabricated using different combinations of relief spaces and escape holes. After impression taking, test and control casts were scanned and three-dimensional digital models were superimposed. Negative deviations were recorded at the point of the alveolar crest, the posterior part of the flabby tissue, and the middle of the palate, while positive deviations were recorded at the point of the anterior part of flabby tissue. The amount and characteristics of tissue displacement differed with tray design and the relief method used.


Assuntos
Técnica de Moldagem Odontológica/instrumentação , Gengiva/patologia , Arcada Edêntula/patologia , Maxila/patologia , Processo Alveolar/patologia , Atrofia , Técnica de Moldagem Odontológica/normas , Modelos Dentários , Desenho de Equipamento , Humanos , Imageamento Tridimensional/métodos , Técnicas In Vitro , Lasers , Teste de Materiais , Imagem Óptica/métodos , Palato/patologia
19.
Int J Prosthodont ; 29(5): 514-21, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27611759

RESUMO

PURPOSE: The aim of this study was to detail and assess the capability of a novel methodology to 3D-quantify tooth wear progression in a patient over a period of 12 months. MATERIALS AND METHODS: A calibrated stainless steel model was used to identify the accuracy of the scanning system by assessing the accuracy and precision of the contact scanner and the dimensional accuracy and stability of casts fabricated from three different types of impression materials. Thereafter, the overall accuracy of the 3D scanning system (scanner and casts) was ascertained. Clinically, polyether impressions were made of the patient's dentition at the initial examination and at the 12-month review, then poured in type IV dental stone to assess the tooth wear. The anterior teeth on the resultant casts were scanned, and images were analyzed using 3D matching software to detect dimensional variations between the patient's impressions. RESULTS: The accuracy of the 3D scanning system was established to be 33 µm. 3D clinical analysis demonstrated localized wear on the incisal and palatal surfaces of the patient's maxillary central incisors. The identified wear extended to a depth of 500 µm with a distribution of 4% to 7% of affected tooth surfaces. CONCLUSION: The newly developed 3D scanning methodology was found to be capable of assessing and accounting for the various factors affecting tooth wear scanning. Initial clinical evaluation of the methodology demonstrates successful monitoring of tooth wear progression. However, further clinical assessment is needed.


Assuntos
Modelos Dentários/normas , Imageamento Tridimensional/normas , Imagem Óptica/normas , Desgaste dos Dentes/diagnóstico , Sulfato de Cálcio/normas , Revestimento para Fundição Odontológica/normas , Materiais para Moldagem Odontológica/normas , Técnica de Moldagem Odontológica/normas , Progressão da Doença , Feminino , Seguimentos , Humanos , Incisivo/patologia , Pessoa de Meia-Idade , Aço Inoxidável/normas , Atrito Dentário/diagnóstico , Atrito Dentário/patologia , Coroa do Dente/patologia , Desgaste dos Dentes/patologia
20.
PLoS One ; 11(7): e0158800, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27383409

RESUMO

Intraoral digital impressions have been stated to meet the clinical requirements for some teeth-supported restorations, though fewer evidences were proposed for larger scanning range. The aim of this study was to compare the accuracy (trueness and precision) of intraoral digital impressions for whole upper jaws, including the full dentitions and palatal soft tissues, as well as to determine the effect of different palatal vault height or arch width on accuracy of intraoral digital impressions. Thirty-two volunteers were divided into three groups according to the palatal vault height or arch width. Each volunteer received three scans with TRIOS intraoral scanner and one conventional impression of whole upper jaw. Three-dimensional (3D) images digitized from conventional gypsum casts by a laboratory scanner were chose as the reference models. All datasets were imported to a specific software program for 3D analysis by "best fit alignment" and "3D compare" process. Color-coded deviation maps showed qualitative visualization of the deviations. For the digital impressions for palatal soft tissues, trueness was (130.54±33.95)µm and precision was (55.26±11.21)µm. For the digital impressions for upper full dentitions, trueness was (80.01±17.78)µm and precision was (59.52±11.29)µm. Larger deviations were found between intraoral digital impressions and conventional impressions in the areas of palatal soft tissues than that in the areas of full dentitions (p<0.001). Precision of digital impressions for palatal soft tissues was slightly better than that for full dentitions (p = 0.049). There was no significant effect of palatal vault height on accuracy of digital impressions for palatal soft tissues (p>0.05), but arch width was found to have a significant effect on precision of intraoral digital impressions for full dentitions (p = 0.016). A linear correlation was found between arch width and precision of digital impressions for whole upper jaws (r = 0.326, p = 0.034 for palatal soft tissues and r = 0.485, p = 0.002 for full dentitions). It was feasible to use the intraoral scanner to obtain digital impressions for whole upper jaws. Wider dental arch contributed to lower precision of an intraoral digital impression. It should be confirmed in further studies that whether accuracy of digital impressions for whole upper jaws is clinically acceptable.


Assuntos
Arco Dental/anatomia & histologia , Técnica de Moldagem Odontológica/normas , Maxila/anatomia & histologia , Palato/anatomia & histologia , Dente/anatomia & histologia , Adulto , Sulfato de Cálcio , Desenho Assistido por Computador , Materiais para Moldagem Odontológica , Técnica de Moldagem Odontológica/instrumentação , Modelos Dentários , Dentição , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/métodos , Masculino , Reprodutibilidade dos Testes , Software , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...