Evaluation of the influence of the impression technique, scanning direction and type of scanner on the accuracy of the final model / Avaliação da influência da técnica de impressão, direção de digitalização e tipo de scanner na precisão do modelo final

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)

Evaluation of marginal adaptation in three-unit frameworks fabricated with conventional and powder-free digital impression techniques

PURPOSE: The purpose of this in vitro study was to evaluate the marginal misfits of three-unit frameworks fabricated with conventional and digital impressions techniques. MATERIALS AND METHODS: Thirty brass canine and second premolar abutment preparations were fabricated by using a computer numerical control machine and were randomly divided into 3 groups (n=10) as follows: conventional impression group (Group Ci), Cerec Omnicam (Group Cdi), and 3shape TRIOS-3 (Group Tdi) digital impression groups. The laser-sintered metal frameworks were designed and fabricated with conventional and digital impressions. The marginal adaptation was assessed with a stereomicroscope at ×30 magnification. The data were analyzed with 1-way analysis of variances (ANOVAs) and the independent simple t tests. RESULTS: A statistically significant difference was found between the frameworks fabricated by conventional methods and those fabricated by digital impression methods. Multiple comparison results revealed that the frameworks in Group Ci (average, 98.8 ± 16.43 µm; canine, 93.59 ± 16.82 µm; premolar, 104.10 ± 15.02 µm) had larger marginal misfit values than those in Group Cdi (average, 63.78 ± 14.05 µm; canine, 62.73 ± 13.71 µm; premolar, 64.84 ± 15.06 µm) and Group Tdi (average, 65.14 ± 18.05 µm; canine, 70.64 ± 19.02 µm; premolar, 59.64 ± 16.10 µm) (P=.000 for average; P=.001 for canine; P.05). CONCLUSION: The three-unit frameworks fabricated with digital impression techniques showed better marginal fit compared to conventional impression techniques. All marginal misfit values were clinically acceptable.

Questionnaire survey for the clinical trial participants who experienced both digital and conventional impression

PURPOSE: The aim of this study was to assess the patients' perception, acceptance, and preference of the difference between a conventional impression and digital impression through questionnaire survey. MATERIALS AND METHODS: Thirteen (6 male, 7 female) subjects who experienced both digital and conventional impression at the same day were enrolled in this study. Conventional impression were taken with polyvinylsiloxane and digital impression were performed using a newly developed intra-oral scanner. Immediately after the two impressions were made, a survey was conducted with the standardized questionnaires consisting of the following three categories; 1) general dental treatment 2) satisfaction of conventional impression 3) satisfaction of digital impression. The perceived source of satisfaction was evaluated using Likert scale. The distribution of the answers was assessed by percentages and statistical analyses were performed with the paired t-test, and P < 0.05 was considered significant. RESULTS: There were significant differences of the overall satisfaction between two impression methods (P < 0.05). Digital impression showed high satisfaction in less shortness of breath and odor to participants compared to conventional impression. The use of an oral scanner resulted in a discomfort of TMJ due to prolonged mouth opening and in lower score of the scanner tip size. CONCLUSION: It was confirmed that the preference for the digital impression using intraoral scanner is higher than the conventional impression. Most survey participants said they would recommend the digital impression to others and said they preferred it for future prosthetic treatment.

Comparison of patient satisfaction with digital and conventional impression for prosthodontic treatment / 대한치과보철학회지

PURPOSE: The present study aims at researching the subjective satisfaction of patients who have experienced both conventional impression taking and digital impression taking to measure the possibility of wide clinical application of digital impression. MATERIALS AND METHODS: The study surveyed 170 adult patients over the age of 20, between October 2015 and April 2016, who voluntarily consented to participation and who experienced both conventional impression and digital impression at five dental hospitals that use intraoral digital impression. A total of 128 surveys were used for data analysis, involving frequency analysis, multiple response frequency analysis, descriptive statistics, and contingency table analysis, with the significance level set at 0.05. RESULTS: Responses on the reason for taking impressions using the digital method appeared in the order of 'for implant treatment' (43.8%), 'for crown treatment' (30.5%), and 'for inlay treatment' (15.6%). Patients satisfaction was higher for digital impression taking than conventional impression taking (P<.05). As the preferred choice of impression, digital impression (60.2%) was higher than conventional impression (11.7%). Responses on the reason for choosing digital impression taking appeared in the order of 'no vomiting reflex' (35.1%), 'reliability of 3D digital scanning' (33.8%), and 'short time' (33.8%). CONCLUSION: The patients preferred digital impression taking to conventional impression taking in terms of satisfaction.