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1.
Int J Prosthodont ; 34(1): 27-36, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33570517

RESUMEN

PURPOSE: To investigate the effect of training on scanning accuracy of complete arch scans (CAS) performed by first-time users, with a distinction made between specific training (repeated performance of CAS) and nonspecific training (simple use of an intraoral optical scanner for a sextant scan in the context of a CAD/CAM teaching module). MATERIALS AND METHODS: A total of 36 students with no experience in intraoral scanning were randomized into three groups (n = 12 per group) according to the number of CAS sessions: three sessions (3S), two sessions (2S), and one session (1S). Each student had to perform 10 CAS per scanning session. Sessions were scheduled at T0, T1, and T2 for group 3S; at T0 and T2 for group 2S; and at T2 for group 1S. Before the final scanning session in each group (ie, the first scanning session in group 1S), the students completed a CAD/CAM teaching module, which included fabrication of a monolithic crown in a fully digital chairside workflow. RESULTS: In all groups, repeated CAS resulted in improved scanning accuracy. Participation in the CAD/CAM module had a positive effect on initial accuracy for CAS. Mean absolute deviations in cross-arch distance were 84 µm (T0), 68 µm (T1), and 63 µm (T2) for group 3S; 79 µm (T0) and 61 µm (T2) for group 2S; and 67 µm (T2) for group 1S. CONCLUSION: To perform CAS with the best possible accuracy, specific training is highly recommended. In addition, nonspecific training leads to an improvement in initial scanning accuracy.


Asunto(s)
Diseño Asistido por Computadora , Coronas , Técnica de Impresión Dental , Modelos Dentales , Humanos , Imagenología Tridimensional , Flujo de Trabajo
2.
Int J Prosthodont ; 34(1): 21-26, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33570516

RESUMEN

PURPOSE: To investigate the effect of training on scanning times of complete-arch scans (CAS) performed by first-time users, with a distinction made between specific training (repeated practice of CAS) and nonspecific training (simple use of an intraoral scanner for a sextant scan in the context of a student CAD/CAM course). METHODS: Thirty-six students with no experience in intraoral scanning were randomized into three groups (n = 12 per group) according to the number of specific CAS training sessions: three sessions (3S), two sessions (2S), and one session (1S). Each student performed 10 CAS per scanning session. These sessions were scheduled at baseline (T0), T1 (2 weeks after T0), and T2 (4 weeks after T0) for group 3S; at T0 and T2 for group 2S; and at T2 for group 1S. Before the final scanning session in each group (ie, the first scanning session in group 1S), the students participated in a CAD/CAM course (3 weeks after T0) in which a monolithic crown was fabricated in a fully digital chairside workflow. The scanning time was measured as the time between the activation and termination of the scanning mode of the intraoral device. Data were analyzed using SPSS Statistics 25 (IBM). The level of significance was set to α = .05. RESULTS: A continual decrease in scanning time was observed for all groups as experience in intraoral scanning increased. The mean scanning times were as follows: for group 3S, 305 seconds at T0, 246 seconds at T1, and 233 seconds at T2; for group 2S, 380 seconds at T0 and 303 seconds at T2; and for group 1S, 355 seconds at T2. When compared to group 1S after it had received nonspecific training only, the effect of a single specific training session in groups 3S and 2S was not significant (P = .4428). However, two specific training sessions had a significant effect on scanning time compared to nonspecific training only (P = .0005). CONCLUSION: Training does affect the scanning time required for CAS. To perform such scans in a time-efficient manner, dental practitioners should undertake training that comprises at least 12 CAS.


Asunto(s)
Técnica de Impresión Dental , Odontólogos , Diseño Asistido por Computadora , Coronas , Humanos , Rol Profesional
3.
Int J Prosthodont ; 34(1): 61-69, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33570521

RESUMEN

PURPOSE: To compare the marginal and internal gap values of different types of ceramic crowns fabricated based on digital and conventional impression methods. MATERIALS AND METHODS: Ten noncarious extracted human teeth were prepared, and 60 restorations were made using six different impression and fabrication methods. Silicone replicas were obtained for marginal and internal gap evaluation. Statistical analyses were performed using Mann-Whitney U and Kruskal-Wallis tests (P < .05). RESULTS: Statistically significant differences were found among various impression and fabrication methods. The smallest gap value was shown by the monolithic zirconia indirect digital scanning group (31.13 µm), and the largest for the lithium disilicate indirect digital scanning group (90.09 µm). CONCLUSION: The marginal and internal gap values of the restorations in the present study were 31.13 to 90.09 µm. The marginal and internal discrepancies of the tested materials were considered clinically acceptable.


Asunto(s)
Técnica de Impresión Dental , Adaptación Marginal Dental , Diseño Asistido por Computadora , Coronas , Porcelana Dental , Diseño de Prótesis Dental , Humanos
4.
Int J Prosthodont ; 34(1): 101-108, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33570525

RESUMEN

PURPOSE: To compare the accuracy of six intraoral scanners in two different partially edentulous maxillary models and to evaluate the effect of scanning sequence on accuracy. MATERIALS AND METHODS: Maxillary Kennedy Class I and Class IV situations were used as reference models. The reference datasets were obtained by scanning the models using a highly accurate industrial scanner (ATOS Core 80, GOM). The following six intraoral scanners were evaluated: Trios 3 (3Shape), iTero Element 2 (Align Technology), Emerald (Planmeca), CEREC Omnicam (Dentsply Sirona), CEREC Primescan (Dentsply Sirona), and Virtuo Vivo (Dental Wings). A total of 120 scans from both models were obtained using the six intraoral scanners and divided into two groups based on scanning sequence. Accuracy was evaluated by deviation analysis using 3D image processing software (Geomagic Studio 12, 3D Systems). Kruskal Wallis and Mann-Whitney U tests were performed (P ≤ .05) for statistical analysis. RESULTS: There were significant differences in the accuracy of digital impressions among intraoral scanners and scanning sequences. The trueness of the Trios scanner and the precision of the Trios, Primescan, and iTero scanners were significantly higher than for the other scanners. The Emerald had the lowest accuracy among the six intraoral scanners tested. Accuracy was affected by scanning sequence when using the Virtuo Vivo, Emerald, Primescan, and iTero. CONCLUSION: In Kennedy Class I and Class IV partially edentulous cases, it is useful to consider that the intraoral scanner used may affect the accuracy of the digital impression.


Asunto(s)
Técnica de Impresión Dental , Modelos Dentales , Diseño Asistido por Computadora , Arco Dental , Dentición , Imagenología Tridimensional
5.
J Biol Regul Homeost Agents ; 35(1): 161-169, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33435664

RESUMEN

For dental impression of a prepared tooth, the goal is a void-free negative representation from which an accurate cast of a tooth and its surrounding tissue can be reproduced. This in-vitro study assessed and compared the reproduction accuracies of surface detail obtained with three different dental elastomeric impression materials: vinyl polysiloxane (VPS), vinyl polyether silicone (VPES), and polyether (PE). A stainless-steel model with two abutments was used, with impressions taken 10 times for each material, for 20 abutment impressions per group, using a two-phase, one-step technique (heavy body/light body). The impressions were removed and assessed for numbers of enclosed voids and open voids visible on the surface. The defect frequency was 95% for impressions with the VPS and VPES materials, and 30% for the PE material. No significant differences were seen for number of impressions with defects for VPS versus VPES. Significant differences were seen for VPS and VPES versus the PE material (P <.05). No significant differences were seen for the defect type distributions across these three impression materials. The PE impression material showed better accuracy for reproduction of surface detail of these dental impressions compared to the VPS and VPES impression materials.


Asunto(s)
Materiales de Impresión Dental , Técnica de Impresión Dental , Modelos Dentales , Ensayo de Materiales , Reproducibilidad de los Resultados , Propiedades de Superficie
6.
Niger J Clin Pract ; 24(1): 1-7, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33473018

RESUMEN

In the domain of orthodontics, plaster models are contemplated as one of the important tools for diagnosis and treatment planning. In Dentistry, technological advancement has developed in the section of diagnostic devices, for example, the utilization of a 3D intraoral scanner, which can convert plaster models into digital models. With in-office utilization of this system, orthodontists can more meticulously and precisely construct custom braces, clear aligners, and orthodontic appliances. The digital data can be stored as a stereolithography file; it eliminates the disadvantages encountered with the storage of plaster models like breakage, space required, and distortion of the plaster models. ITero®element is the intraoral laser scanner (ILS) which utilizes parallel confocal scanning technology which maximizes the accuracy of the scan. By utilizing the iTero scanner, the dental measurement can be performed in OrthoCADTM software which is highly accurate. The objective of the contemporary study is to review the literature of studies on in-vivo and ex-vivo scanning with the iTero system.


Asunto(s)
Imagenología Tridimensional , Ortodoncia , Diseño Asistido por Computadora , Técnica de Impresión Dental , Modelos Dentales , Humanos , Aparatos Ortodóncicos , Cintigrafía
7.
Braz. dent. sci ; 24(1): 1-13, 2021. tab, ilus
Artículo en Inglés | LILACS, BBO - Odontología | ID: biblio-1145439

RESUMEN

Objective: The purpose of this study is to evaluate the influence of the type of scanner and scanning direction on the accuracy of the final cast. Material and Methods: A partial master cast was used as a reference. A total of 128 scans were obtained and divided into two groups: the conventional method and the digital method. The digital group was divided into three groups: TRIOS 3, Omnicam and CS 3600. Each of these groups was subdivided according to the scanning direction, and each scan was overlaid on the digital reference cast to measure the trueness and precision of the procedures. Results: The overall precision values for the type of impression were 59.89 ± 13.08 µm for conventional and 13.42 ± 4.28 µm for digital; the values for trueness were 49.37 ± 19.13 µm for conventional and 53.53 ± 4.97 µm for digital; the scanning direction trueness values were 53.05 ± 4.36 µm for continuous and 54.03 ± 5.52 µm for segmented; and the precision values were 14.18 ± 4.67 µm for continuous and 12.67 ± 3.75 µm for segmented (p> 0.05). For the scanner type, the trueness values were 50.06 ± 2.65 µm for Trios 3, 57.45 ± 4.63 µm for Omnicam, and 52.57 ± 4.65 µm for Carestream; and those for precision were 11.7 ± 2.07 µm for Trios 3, 10.09 ± 2.24 µm for Omnicam, and 18.49 ± 2.42 µm for Carestream (p <0.05). Conclusions: The digital impression method is the most favorable method regarding precision; in terms of trueness, there are no differences between the types of impressions. (AU)


Objetivo: O objetivo deste estudo é avaliar a influência do tipo de técnica de moldagem, tipo de escâner intraoral e direção do escaneamento na precisão do modelo final. Material e Métodos: Um modelo parcial mestre foi usado como referência. Um total de 128 escaneamentos foi obtido e dividido em dois grupos: o método convencional (n = 32) e o método digital (n = 96). O grupo digital foi dividido em três grupos: TRIOS 3 (n = 32), Omnicam (n = 32) e CS 3600 (n = 32). Cada um desses grupos foi subdividido de acordo com a direção do escaneamento (n = 16), e cada escaneamento foi sobreposto ao modelo de referência digital para medir a veracidade e precisão dos procedimentos. Resultados: Os valores gerais de precisão para o tipo de impressão foram 59,89 ± 13,08 µm para convencional e 13,42 ± 4,28 µm para digital; os valores de veracidade foram 49,37 ± 19,13 µm para convencional e 53,53 ± 4,97 µm para digital; os valores de veracidade para a direção de digitalização foram 53,05 ± 4,36 µm para contínua e 54,03 ± 5,52 µm para segmentada; e os valores de precisão foram 14,18 ± 4,67 µm para contínua e 12,67 ± 3,75 µm para segmentada (p> 0,05). Para o tipo de scanner, os valores de veracidade foram 50,06 ± 2,65 µm para Trios 3, 57,45 ± 4,63 µm para Omnicam e 52,57 ± 4,65 µm para Carestream; e os de precisão foram 11,7 ± 2,07 µm para Trios 3, 10,09 ± 2,24 µm para Omnicam e 18,49 ± 2,42 µm para Carestream (p <0,05). Conclusões: O método de moldagem digital é o método mais favorável em relação à precisão; em termos de veracidade, não há diferenças entre os tipos de impressão (AU)


Asunto(s)
Técnica de Impresión Dental , Precisión de la Medición Dimensional , Exactitud de los Datos
8.
Beijing Da Xue Xue Bao Yi Xue Ban ; 52(6): 1112-1116, 2020 Dec 18.
Artículo en Chino | MEDLINE | ID: mdl-33331323

RESUMEN

OBJECTIVE: To assess the effect of disinfectant (Cavicide) with benzethon chloramine and isopropanol as main active ingredients disinfectant on dental impression accuracy. METHODS: The effect of Cavicide on three impression materials (alginate, polyether and vinylpolysiloxane) were assessed using a standard model. The standard model was digitized by an extraoral scanner (IScan D103i, Imetric). For each kind of impression materials, thirty impressions were taken following the manufactures' instruction in the same conditions. Subsequently, the impressions were randomly divided into three groups, with ten impressions in each group. After the impression taking was completed, the three groups underwent pure water rinse for 1 min (blank control, BC), 2% glutaraldehyde solution immersion disinfection for 30 min (glutaraldehyde, GD), and Cavicide solution spray disinfection for 5 min (Cavicide, CC), respectively. All the impressions were digitized by the extraoral scanner (IScan D103i, Imetric) after disinfection and exported to a dedicated three-dimensional analysis software (Geomagic Qualify 2014, Geomagic, USA). In the software, the digital models of the impressions were trimmed to teeth and then superimposed with the digitized standard model via best-fit alignment. Root mean square (RMS) was used to evaluate the deviations between the impression and the standard model. The deviation in the anterior and posterior regions was evaluated respectively. One-way ANOVA test and the LSD post-hoc test were used to compare the deviations between the three groups (P < 0.05). The color map of each superimposition was saved for visual analysis. RESULTS: For the polyether and vinylpolysiloxane materials, the difference between the three groups was not statistically significant (P=0.933, P=0.827). For the alginate material, the difference in posterior region between group GD and group BC, as well as group GD and group CC were statistically significant (GD vs. BC, P=0.001; GD vs. CC, P=0.002), while the difference between group BC and group CC was not statistically significant (P=0.854). The visual analysis showed an obvious deviation in the buccal-lingual direction in group GD. CONCLUSION: Disinfectant (Cavicide) with benzethon chloramine and isopropanol as main active ingredients using spray disinfection has no effect on the accuracy of the alginate, polyether and vinylpolysiloxane impressions.


Asunto(s)
Desinfectantes , 2-Propanol , Cloraminas , Materiales de Impresión Dental , Técnica de Impresión Dental , Modelos Dentales , Desinfección
9.
Evid Based Dent ; 21(4): 138-139, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-33339976

RESUMEN

Source of funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectorsType of study/design Randomised controlled trial (RCT) with parallel design.Subjects This RCT was conducted at the Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Centre of Dental Medicine, University of Zurich, Zurich, Switzerland. Ten patients, six women and four men, with a mean age of 62 years and an age range of 49-77 years, requiring posterior tooth-supported 3-unit fixed partial dentures (FPDs) were included in this RCT. The abutment teeth were six molars and six premolars in the maxilla and five molars and three premolars in the mandible. The patients fulfilled the following inclusion criteria: they all were >18 years, with a full mouth plaque score <25% and a full mouth bleeding score <25%. They all needed a posterior tooth-supported FPD, in which the third molar was not an abutment tooth. Only abutments with no extensive pretreatment were eligible. Adjacent and opposing teeth should be healthy or adequately restored.Treatment Three intraoral digital scanning systems (Lava C.O.S.; 3M [Lava], iTero; Align Technology Inc [iTero], Cerec Bluecam; Dentsply Sirona [Cerec]) and conventional light/regular body polyether impression in a stock tray were made on each of the included participants by the same clinician. The opposing arch impression was made in alginate. The sequence of the four techniques was computer generated and concealed in opaque sealed envelopes. Three calibrated experienced clinicians were involved in the treatment. They followed the published guidelines for preparing abutments that receive CAD/CAM ceramic FPDs. After interim prosthesis removal and double retraction cord application, the digital or the conventional impression procedure was started as dictated by the random sequence. Scans were done according to the manufacturer's guidelines, whereby Lava and Cerec required powdering of the teeth by titanium oxide and iTero did not.Main outcome Time needed for obtaining a scan or an impression was calculated. For digital scans it consisted of the time required for powdering, scanning and occlusal registration, while in conventional impression it started from the beginning of impression mixing till tray removal. The number of impression or scan remakes required until results fulfilling the quality criteria were obtained was also recorded. Visual analogue scale (VAS) was used to rate the perception of both, clinicians and patients for the procedures. Patients were asked to rate their comfort with the procedure, while clinicians rated both difficulty and comfort, where 0 indicated uncomfortable and simple and 100 difficult and comfortable. Subjective assessment of the time as judged by the clinicians and the patients was also reported.Main results Generally speaking, conventional impression was better than the three complete arch digital scans, regarding time required in seconds, difficulty for clinicians, comfort and time perception of both patients and clinicians. Number of remakes were highest in iTero (7), followed by Lava, conventional impression and finally Cerec (0). The time required for each technique differed significantly Polyether = 658 (95%CI 528-782) Cerec = 1776 (95%CI 804-2386) iTero = 1107 (785 - 2091). A significant difference was found neither among the three digital impressions, nor between the conventional impression and Lava (µ = 1091, 95%CI [717-1465]). The same findings were reported regarding difficulty for the clinicians. A significant difference was reported between conventional impression (µ = 15, 95%CI [7-24]) and both Cerec (µ = 67, 95%CI [58-77]) and iTero (µ = 43, 95%CI [25-62]). No significant difference was reported among the studied techniques regarding patients' comfort and time perceptions of both clinicians and patients except for a difference in the patients' time perception of Cerec and conventional impression, where P = .035. Regarding the clinicians' comfort a significant difference was only found between conventional impression (µ = 82, 95%CI [69-94]) and Cerec (µ = 32, 95%CI [18-46]).Conclusion Within the limitations of this RCT, it can be concluded that complete arch conventional impression is objectively less time consuming and subjectively preferred by both clinicians and patients when compared to digital scanning. Digital scanning techniques, requiring powdering, are more difficult for the clinicians than powderless ones and conventional impression.


Asunto(s)
Materiales de Impresión Dental , Técnica de Impresión Dental , Anciano , Cerámica , Dentadura Parcial Fija , Femenino , Humanos , Masculino , Persona de Mediana Edad , Suiza , Flujo de Trabajo , Circonio
10.
Am J Orthod Dentofacial Orthop ; 158(5): 759-766, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-33131565

RESUMEN

INTRODUCTION: The use of digital models in orthodontics is becoming increasingly widespread. This study aimed to evaluate the accuracy and performance of digital intraoral scanning under 4 different intraoral environmental conditions. METHODS: Four digital models were acquired with TRIOS intraoral scanner (3Shape, Copenhagen, Denmark) for 50 subjects. A total of 200 digital models were divided into 4 groups as follows: daylight and saliva (group 1), daylight with saliva isolation (group 2), reflector light and saliva (group 3), and relatively dark oral environment and saliva (group 4). The 4 digital models were superimposed, and the edges of the models were trimmed to create common boundaries (Geomagic Control X; 3D Systems, Rock Hill, SC). Group 2 models were used as a reference and superimposed separately with the models of the other 3 groups. Deviations between corresponding models were compared as means of negative deviation, means of positive deviation, in total area, out total area, positively positioned areas, and negatively positioned areas. In addition, all groups were compared in terms of scanning time, the total number of images, and the mesiodistal width of teeth. RESULTS: Overlapping of group 1 with the reference model (group 2), a surface deviation of 13.1% (out total area) was observed. This analysis revealed that a 13% deviation was caused by the presence of saliva alone. This rate was 12.6% in group 3 and 15.5% in group 4, respectively. The values for means of negative deviation were -55 µ in group 1,-63 µ in group 3, and -68 µ in group 4. Means of positive deviation values were distributed among groups as follows: 68 µ in group 1, 69 µ in group 3, and 78 µ in group 4. The total number of images was observed, at least in group 4. CONCLUSIONS: The intraoral scanner performance was affected by different environmental conditions, and that caused variations on the surface of digital models. However, the performance of the intraoral scanner was independent of the scanning time and mesiodistal width of the teeth.


Asunto(s)
Técnica de Impresión Dental , Saliva , Diseño Asistido por Computadora , Modelos Dentales , Humanos , Imagenología Tridimensional
11.
Shanghai Kou Qiang Yi Xue ; 29(4): 445-448, 2020 Aug.
Artículo en Chino | MEDLINE | ID: mdl-33089300

RESUMEN

PURPOSE: The aim of this study was to assess and compare patient satisfaction and time required between silicon rubber impression and intraoral scanning impression. METHODS: Six undergraduates participated in this study. silicon rubber impression and intraoral scanning impression were taken, the time required to obtain the impressions and the scores of visual analog scale(VAS) were recorded. SPSS 23.0 software package was used for statistical analysis. RESULTS: The time and patients satisfaction of silicon rubber impression were better than intraoral scanning impressions, and there were significant differences between the two groups(P<0.05). CONCLUSIONS: Using silicon rubber impression, the patient experience is better. To use intraoral scanning impression technology, dentists should be more skilled. With the role-playing method,dental interns can learn the operation key points and precautions of different impression-taking methods even better.


Asunto(s)
Goma , Silicio , Diseño Asistido por Computadora , Técnica de Impresión Dental , Humanos , Cintigrafía
12.
Quintessence Int ; 51(10): 838-843, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32954391

RESUMEN

The proposed denture replication method shows a predictable workflow for fabricating complete dentures for patients with existing dentures. The replication technique is a method of fabricating new removable complete dentures utilizing the existing prosthesis as the foundation for a new denture. The technique has some advantages such as allowing the clinician to copy the tooth shape and contours of the existing prosthesis while modifying borders and intaglio surfaces. The denture replication method links proven methods of obtaining functional impressions using soft reline materials to a straightforward digital process. Utilizing the new "copy-denture" feature in the 3Shape software, it is possible to significantly reduce the number of appointments and laboratory labor involved in denture fabrication. The denture replication method protocol is increasing efficiency by reducing the amount of clinical procedures and visits, resulting in decreased treatment time and costs while providing a satisfactory clinical solution.


Asunto(s)
Implantes Dentales , Diseño de Dentadura , Técnica de Impresión Dental , Dentadura Completa , Dentadura Parcial , Humanos
13.
J Oral Sci ; 62(4): 439-443, 2020 Sep 26.
Artículo en Inglés | MEDLINE | ID: mdl-32908080

RESUMEN

This study evaluated the effect of a modified tray design on the accuracy of implant impressions in comparison with the non-splinted and splinted impression techniques. Two titanium frameworks were produced to fit two parallel implants and two divergent implants with a 15o angle. According to the frameworks employed, two acrylic resin master models were fabricated. For each model, 10 impressions were taken with every technique. The maximum framework principal strain was calculated for every generated cast. For the parallel implant model, the strains of the non-splinted (118.4 µÎµ), splinted (89.0 µÎµ), and modified tray design impression (49.4 µÎµ) techniques were statistically similar (P = 0.16). For the divergent implant model, all the impression techniques showed a considerably higher strain than the parallel implant model. The splinted (287.0 µÎµ) and the modified (262.9 µÎµ) tray design impression techniques showed similar strains for the divergent implant model, which were significantly less than the strains for the non-splinted impression (518.0 µÎµ) technique (P < 0.05). Therefore, for two parallel implants, all the impression techniques exhibited similar accuracy. When angulation existed between the implants, the splinted and the modified tray design impression techniques were more accurate than the non-splinted impression technique.


Asunto(s)
Implantes Dentales , Técnica de Impresión Dental , Materiales de Impresión Dental , Modelos Dentales , Prótesis Dental de Soporte Implantado
14.
J Orofac Orthop ; 81(6): 427-439, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32897413

RESUMEN

PURPOSE: This study investigates the accuracy of abutment transfer with current impression materials and provides a concise overview, including other relevant factors, in order to enable clinicians to make an informed decision about the optimal impression for this treatment procedure. METHODS: In all, 96 impressions of a cadaver head with two orthodontic miniscrews in place were taken with four common impression materials by two observers and using two methods of application. After pouring with a standard type IV stone and abutment transfer, all models and the upper jaw (which had been separated from the head) were scanned in a standard model scanner (Zirkonzahn® [Zirkohnzahn GmbH, Gais, Italy] S600 ARTI) and evaluated using a computer-aided design (CAD) program (GOM-Inspect [Gesellschaft für optische Messtechnik m.b.H., Braunschweig, Germany]). The deviations were measured at six points per screw and statistically evaluated with SPSS® (IBM, Chicago, IL, USA). RESULTS: Optimal values were obtained with biphasic polyvinylsiloxane, while monophasic polyvinylsiloxane, alginate and polyether also resulted in acceptable accuracy. Observer experience showed no effect and the method of application had only a minor effect on accuracy. CONCLUSIONS: Within the limitations of this study, it seems that all impression materials are suitable for miniscrew abutment transfer, provided that methods of intraoral adaptation of the orthodontic appliance can be employed. If higher accuracy is needed or for clinicians with less experienced, a biphasic polyvinylsiloxane impression with the putty-wash technique should be used as this combination reduces setting time. The most cost-effective version, alginate, can be used if the consequences of greater deviations can be handled. Caution is advised with polyether if undercuts are present.


Asunto(s)
Técnica de Impresión Dental , Modelos Dentales , Materiales de Impresión Dental , Alemania , Italia
15.
Bull Tokyo Dent Coll ; 61(3): 169-178, 2020 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-32801261

RESUMEN

Victim identification following disasters is an important task for the dentist. Use of records of previous dental treatment proved effective in victim identification after the crash of Japan Airlines Flight 123 in 1985. This dental identification procedure can be problematic, however. In exceptional cases, the victim may have had very little or no prior treatment, making identification by this means impossible. The purpose of this study was to establish a new method of dental identification based on morphological comparison of the oral cavity, rather than on evidence of prior dental treatment. This new method involves superimposing 3-dimensional (3-D) models created by digital impression-taking devices, use of which is becoming increasingly widespread in present-day dental treatment. A total of 75 dental models were used to obtain 3-D models. These were then used in a total of 77 superimposition tests. The results demonstrated that the degree of similarity was 98.03-41.30%, and the degree of difference 0.17-29.69%. This indicated that differences among the dental models could be identified with 100% precision. Personal identification by superimposition of such 3-D models offers a useful tool that could compensate for the shortcomings of standard dental identification.


Asunto(s)
Técnica de Impresión Dental , Modelos Dentales , Diseño Asistido por Computadora , Imagenología Tridimensional , Japón
16.
Eur J Prosthodont Restor Dent ; 28(3): 128-141, 2020 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-32750237

RESUMEN

PURPOSE: To present the results obtained with the "Continuous Scan Strategy" (CSS), a direct intraoral scanning technique based on the connection of the implant scan bodies (SBs) with thermoplastic resin. METHODS: 40 patients were restored with 45 long-span monolithic implant-supported zirconia restorations (10 partial prostheses [PP] and 35 full arches [FA]) fabricated via a full-digital workflow after the capture of an intraoral impression (Trios3®) using the CSS technique. The primary outcomes were the marginal adaptation and passive fit of the superstructures, checked at T0 (intraoral try-in of polyurethane or metal replica of the final prosthesis) and T1 (delivery of the final zirconia restoration). The secondary outcomes, registered at T2 (2 years after the delivery of the final prosthesis), were implant survival, prosthetic success, and complications. A throughout statistical analysis was performed. RESULTS: At T0, 40/45 replicas demonstrated a perfect passive fit and adaptation. At T1, one prosthesis had fractured, and at T2, an additional prosthesis had fractured and one had chipped. The implant survival rate was 100%. The prosthetic success was 93.3%. CONCLUSIONS: CSS seems to represent a viable option for capturing accurate intraoral digital impressions for the fabrication of precise long-span implant-supported restorations.


Asunto(s)
Diseño Asistido por Computadora , Prótesis Dental de Soporte Implantado , Técnica de Impresión Dental , Diseño de Prótesis Dental , Humanos , Flujo de Trabajo
17.
J Am Dent Assoc ; 151(9): 684-690, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32711806

RESUMEN

BACKGROUND: Microstomia is a principal clinical symptom in patients with scleroderma. It is characterized by an abnormally small mouth opening, which makes traditional prosthetic rehabilitation difficult. METHODS: First, the primary impression and jaw relation record were acquired using an intraoral scanning technique and the primary diagnostic dentures were fabricated using 3-dimensional printing (3DP). The definitive impression and jaw relation were obtained and digitally scanned. The second diagnostic denture was also made to confirm the esthetic and occlusal effects. Next, the adjusted dentition parts were scanned and milled from a cross-linked polymethyl methacrylate disk. In addition, the titanium alloy frameworks were also fabricated using 3DP. With flasking, the milled dentition parts were inserted and the definitive dentures were finally fabricated and delivered to the patient. RESULTS: The authors constructed the definitive removable partial dentures successfully using the digital methods of intraoral scanning, computer-aided design, and 3DP. CONCLUSIONS AND PRACTICAL IMPLICATIONS: These digital methods provide an alternative option for prosthetic rehabilitation in scleroderma patients with severe microstomia.


Asunto(s)
Dentadura Parcial Removible , Microstomía , Diseño Asistido por Computadora , Técnica de Impresión Dental , Diseño de Dentadura , Humanos
18.
Int J Prosthodont ; 33(4): 410-417, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32639701

RESUMEN

PURPOSE: To evaluate the dimensional accuracy of impressions made using a new fast-setting polyether material. MATERIALS AND METHODS: A metallic reference model with two crown preparations, one inlay preparation, and three stainless steel precision balls was digitized to create a digital reference model. Sixteen one-step impressions were made for each of the four study groups, differing in impression material (regular-setting polyether [RSP] vs fast-setting polyether [FSP]) and technique (monophase vs dualphase), for a total of 64 specimens. Plaster casts fabricated from these impressions were digitized using 3D scans. Global accuracy was studied by evaluating distance and angle deviations between the replica and the reference model. Local accuracy was described in terms of trueness and precision of the aligned individual abutment tooth surfaces. RESULTS: For all impression materials and techniques, the local accuracy at the abutment tooth level was excellent. For surfaces prepared for crowns, mean trueness was < 10 µm, and mean precision < 12 µm. Inlay surfaces were associated with higher inaccuracies (mean trueness < 21 µm and mean precision < 37 µm). The greatest global inaccuracies were generally measured for the cross-arch span, with mean distance changes between -55 µm and -94 µm. For all aspects of studied accuracy, impressions with FSP were at least comparable to those fabricated with RSP. CONCLUSION: Within the limitations of this study, all tested polyether materials would allow for clinically acceptable impression making. The new fast-setting material could be an alternative to regular-setting polyether materials, especially for single crowns and small fixed partial dentures.


Asunto(s)
Técnica de Impresión Dental , Modelos Dentales , Coronas , Materiales de Impresión Dental , Incrustaciones
19.
Artículo en Inglés | MEDLINE | ID: mdl-32630132

RESUMEN

Due to the high prevalence of periodontitis, dentists have to face a larger group of patients with periodontally compromised dentitions (PCDs) characterized by pathologic tooth migration and malocclusion. Impression taking in these patients is challenging due to several undercuts and extensive interdental areas (IAs). The aim of this clinical trial was to analyze the ability of analog and digital impression techniques to display the IAs in PCDs. The upper and the lower jaws of 30 patients (n = 60, age: 48-87 years) were investigated with one conventional impression (CVI) using polyvinyl siloxane and four digital impressions with intraoral scanners (IOSs), namely True Definition (TRU), Primescan (PRI), CS 3600 (CAR), and TRIOS 3 (TIO). The gypsum models of the CVIs were digitalized using a laboratory scanner. Subsequently, the percentage of the displayed IAs in relation to the absolute IAs was calculated for the five impression techniques in a three-dimensional measuring software. Significant differences were observed among the impression techniques (except between PRI and CAR, p-value < 0.05). TRU displayed the highest percentage of IAs, followed by PRI, CAR, TIO, and CVI. The results indicated that the IOSs are superior to CVI regarding the ability to display the IAs in PCDs.


Asunto(s)
Diseño Asistido por Computadora , Técnica de Impresión Dental , Imagenología Tridimensional , Periodontitis , Anciano , Anciano de 80 o más Años , Sulfato de Calcio , Humanos , Persona de Mediana Edad , Periodontitis/complicaciones , Polivinilos , Programas Informáticos
20.
BMC Oral Health ; 20(1): 189, 2020 07 06.
Artículo en Inglés | MEDLINE | ID: mdl-32631333

RESUMEN

BACKGROUND: Chairside systems are becoming more popular for fabricating full-ceramic single restorations, but there is very little knowledge about the effect of the entire workflow process on restoration fit. Therefore, this study aimed to compare the absolute marginal discrepancy (AMD) and the full internal fit (FULL) of all-ceramic crowns made by two chairside systems, Planmeca FIT and CEREC, with detailed and standard mill settings. METHODS: One upper molar was prepared for an all-ceramic crown in human cadaver maxilla. Full-arch scans were made by Emerald or Omnicam four times each. Twenty-four e.max crowns were designed and milled by the Planmill 30s or 40s or CEREC MCXL mills with either detailed or standard settings. The cadaver tooth was extracted, and each crown was fixed on it and scanned by a high-resolution microCT scanner. The AMD and FULL were measured digitally in mesio-distal and bucco-lingual 2D slices. The actual and predicted times of the milling were also registered. RESULTS: No differences were observed between detailed or standard settings in either system. The AMD was significantly higher with CEREC (132 ± 12 µm) than with either Planmill 30s (71 ± 6.9 µm) or 40s (78 ± 7.7 µm). In standard mode, the FULL was significantly higher with CEREC (224 ± 9.6 µm) than with either Planmill 30s (169 ± 8.1 µm) or 40s (178 ± 8.5 µm). There was no difference between actual and predicted time with the two Planmeca models, but with CEREC, the actual time was significantly higher than the predicted time. The 30s had significantly higher actual and predicted times compared to all other models. Across all models, the average milling time was 7.2 min less in standard mode than in detailed mode. CONCLUSIONS: All fit parameters were in an acceptable range. No differences in fit between Planmeca models suggest no effect of spindle number on accuracy. The detailed setting has no improvement in the marginal or internal fit of the restoration, yet it increases milling time.


Asunto(s)
Cerámica , Diseño Asistido por Computadora , Coronas , Adaptación Marginal Dental , Diseño de Prótesis Dental , Cadáver , Técnica de Impresión Dental/instrumentación , Humanos
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