Application of digital prosthesis in the repair of palatal fistula in rabbits / 中国组织工程研究

BACKGROUND: Digital impression technology has been widely used in the oral field. Compared with traditional impression technology, it is more convenient and accurate. OBJECTIVE: To explore the application of digital prosthesis for repairing palatal fistula in rabbits. METHODS: The rabbit models of palatal fistula were established by surgery. One month later, 10 rabbit models of palatal fistula were scanned by digital intraoral scanning system. The medical silicone rubber prosthesis for palatal fistula was manufactured by digital impression technology and digital design. After wearing the prosthesis, SUN LB, LAN YY, ZHOU HY, HUY. Application of digital prosthesis In me repair of palatal fistula In rabbits.  Zhongguo Zuzhi Gongcheng Yanjiu. 2020;24(14):2192-2196. DPI:10.3969/j.issn.2095-4344.2228 the accuracy, retention and sealing properties of the prosthesis were examined. The study was approved by the Laboratory Animal Ethical Committee of Hospital of Stomatology, Southwest Medical University. RESULTS AND CONCLUSION: After digital prosthesis repaired palatal fistula, the accuracy, retention and sealing properties of the prosthesis were good. To conclude, the digital prosthesis for palatal fistula repair by digital impression technology achieves accurate repair, and has certain clinical values.

Clinical application and research progress of digital complete denture / 华西口腔医学杂志

Digital technologies use high-precision three-dimensional scanning, intelligence-aided design software, and multi-axis numerical control milling or 3D printing, which can produce restorations with reliable precision and suitable function. However, the development of digital technologies in the field of complete denture restoration has been slow due to the complexity of prosthesis. This review article introduces the current research status and clinical applications of digital complete dentures in prosthodontic clinics and dental laboratories to provide beneficial references to prosthodontists and dental technicians.

Clinical performance of intraoral digital impression for fixed prosthodontics: a Meta-analysis / 华西口腔医学杂志

OBJECTIVES@#To analyze the clinical performance of the intraoral digital impression (IDI) in the fixed prosthodontics.@*METHODS@#Databases of Medline (Ovid), EMBASE, Cochrane Central Register of Controlled Trials, and CNKI were searched for randomized controlled trial (RCT) on the use of IDI in fixed prosthodontics until May 2020. Two reviewers independently screened literature, extracted data, and assessed the risk of bias of included studies. A Meta-analysis was conducted when available.@*RESULTS@#Eleven RCTs involving 618 patients were included in this study. A total of 2 and 3 studies had low and high risks of bias, respectively, and other included studies had a medium risk of bias. Results illustrated that the IDI group could shorten the impression-taken time [SMD=-5.63, 95%CI (-11.25, -0.01), @*CONCLUSIONS@#Evidence indicated a good clinical performance of IDI for fixed prosthodontics. Notably, high-quality studies are expected to further support the conclusion.

Digital workflow of immediate implant-supported restoration for atrophic edentulous patients / 口腔疾病防治

@#Rehabilitation and reconstruction of atrophic edentulous predicament represents significant challenges for implant dentists due to the anatomical conditions of the edentulous jaw. Implant-supported fixed complete dental prostheses represent a scientifically and clinically validated treatment for recovering patients, masticatory function and esthetic effect. However, the highly demanding implant surgical techniques and complex rehabilitation procedures for immediate functional reconstruction make it difficult to achieve the desired treatment outcomes. The application of digital and CAD/CAM technology in various stages of the treatment process is logical for patients and dentists. This article summarizes the workflow of digital-assisted implantation with immediate functional reconstruction of atrophic edentulous combined with a clinical case. Digital-assisted diagnosis, design, implantation, immediate reconstruction and final rehabilitation can optimize the implant surgery and immediate rehabilitation workflow, improve the accuracy of implant-supported immediate functional reconstruction, reduce the demand for a large amount of bone graft, and achieve higher patient satisfaction. The “prosthetic-oriented, begin with the end in mind” concept of edentulous jaw implant prosthetics can accurately and efficiently restore the patient,s beauty and chewing function in a minimally invasive manner, and is worthy of clinical promotion.

Accuracy of 3D digital modeling of dental arches

ABSTRACT Objective: The aim of the study was to verify and compare the accuracy of full-arch digital impressions obtained using two intraoral scanners and three scanning methodologies. Methods: A resin model created with dental 3-D printing was scanned by a reference scanner (Zfx Evolution - Zimmer Biomet, Palm Beach Gardens, FL) in order to obtain a 3D reference; the same resin model was then scanned with two different intraoral scanners (Zfx IntraScan and Carestream 3600 - CS 3600®, Carestream, Rochester, NY, USA) using: Technique A (from tooth #27 up to tooth #17); Technique B (from tooth #11 up to tooth #17 and then from tooth #21 up to tooth #27) and Technique C (from tooth #22 up to tooth #17, and then from tooth #12 up to tooth #27 - the MeshLab software v. 1.3.3 was then used to match the two scans). The scans obtained were superimposed over the reference scan by means of a software, and the volumetric discrepancies were calculated. Results: The mean results for the Zfx Intrascan scanner were: Technique A = 302.47 ± 37.42 µm; Technique B = 180.45 ± 29.86 µm; Technique C = 147.34 ± 28.23 µm. The mean results for the Carestream 3600 scanner were: Technique A = 303.59 ± 40.20 µm; Technique B = 181.53 ± 29.61 µm; Technique C = 142.28 ± 35.33 µm. Technique C, used by both scanners, produced less volumetric discrepancies compared to the other techniques. Conclusions: The scanning technique had a statistically significant effect on the quality of the scan (p< 0.0001), whereas the scanner did not present any significant influence (p= 0.91).

RESUMO Objetivo: o objetivo do presente estudo foi verificar e comparar a precisão de modelos digitais de uma arcada dentária completa obtidos utilizando-se dois tipos de scanners e três metodologias de digitalização. Métodos: um modelo de resina feito com impressão 3D foi digitalizado em um scanner de referência (Zfx Evolution - Zimmer Biomet, Palm Beach Gardens, FL) para se obter uma referência em 3D; o mesmo modelo de resina foi, então, digitalizado com dois scanners intrabucais diferentes (Zfx IntraScan e Carestream 3600 - CS 3600®, Carestream, Rochester, NY, EUA) utilizando: Técnica A (do dente #27 ao dente #17); Técnica B (do dente #11 ao dente #17 e, em seguida, do dente #21 ao dente #27); e Técnica C (do dente #22 ao dente #17 e, em seguida, do dente #12 ao dente #27 - osoftware MeshLab v. 1.3.3 foi, então, usado para mesclar as duas leituras). Em seguida, as imagens digitalizadas foram sobrepostas à imagem de referência, utilizando-se um software, e as discrepâncias volumétricas foram calculadas. Resultados: a média dos resultados para o scanner Zfx Intrascan foram: Técnica A = 302,47 ± 37,42 µm; Técnica B = 180,45 ± 29,86 µm; Técnica C = 147,34 ± 28,23 µm. A média dos resultados para o scanner Carestream 3600 foram: Técnica A= 303,59 ± 40,20 µm; Técnica B = 181,53 ± 29,61 µm; Técnica C = 142,28 ± 35,33 µm. A Técnica C, utilizada em ambos os scanners, produziu as menores discrepâncias volumétricas, quando comparada às outras técnicas. Conclusões: a técnica de digitalização teve um efeito estatisticamente significativo sobre a qualidade do modelo digital (p< 0,0001), enquanto o tipo de scanner usado não apresentou qualquer influência significativa (p= 0,91).

Comparison of different impression techniques for edentulous jaws using three-dimensional analysis

PURPOSE: The purpose of this study was to compare two novel impression methods and a conventional impression method for edentulous jaws using 3-dimensional (3D) analysis software. MATERIALS AND METHODS: Five edentulous patients (four men and one woman; mean age: 62.7 years) were included. Three impression techniques were used: conventional impression method (CI; control), simple modified closed-mouth impression method with a novel tray (SI), and digital impression method using an intraoral scanner (DI). Subsequently, a gypsum model was made, scanned, and superimposed using 3D analysis software. Mean area displacement was measured using CI method to evaluate differences in the impression surfaces as compared to those values obtained using SI and DI methods. The values were confirmed at two to five areas to determine the differences. CI and SI were compared at all areas, while CI and DI were compared at the supporting areas. Kruskal-Wallis test was performed for all data. Statistical significance was considered at P value .05); the difference was .05). CONCLUSION: The CI, SI, and DI methods were effective in making impressions of the supporting areas in edentulous patients. The SI method showed clinically applicability.

Accuracy of digital and conventional dental implant impressions for fixed partial dentures: A comparative clinical study

PURPOSE: The newest technologies for digital implant impression (DII) taking are developing rapidly and showing acceptable clinical results. However, scientific literature is lacking data from clinical studies about the accuracy of DII. The aim of this study was to compare digital and conventional dental implant impressions (CII) in a clinical environment. MATERIALS AND METHODS: Twenty-four fixed zirconia restorations supported by 2 implants were fabricated using conventional open-tray impression technique with splinted transfers (CII group) and scan with Trios 3 IOS (3Shape) (DII group). After multiple verification procedures, master models were scanned using laboratory scanner D800 (3Shape). 3D models from conventional and digital workflow were imported to reverse engineering software and superimposed with high resolution 3D CAD models of scan bodies. Distance between center points, angulation, rotation, vertical shift, and surface mismatch of the scan bodies were measured and compared between conventional and digital impressions. RESULTS: Statistically significant differences were found for: a) inter-implant distance, b) rotation, c) vertical shift, and d) surface mismatch differences, comparing DII and CII groups for mesial and dist al implant scan bodies (P≤.05). CONCLUSION: Recorded linear differences between digital and conventional impressions were of limited clinical significance with two implant-supported restorations.

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.

A new method to measure the accuracy of intraoral scanners along the complete dental arch: A pilot study

PURPOSE: The purpose of this study is to assess the accuracy of three intraoral scanners along the complete dental arch and evaluate the feasibility of the assessment methodology for further in vivo analysis.MATERIALS AND METHODS: A specific measurement pattern was fabricated and measured using a coordinate measuring machine for the assessment of control distances and angles. Afterwards, the pattern was placed and fixed in replica of an upper jaw for their subsequent scans (10 times) using 3 intraoral scanners, namely iTero Element1, Trios 3, and True Definition. 4 reference distances and 5 angles were measured and compared with the controls. Trueness and precision were assessed for each IOS: trueness, as the deviation of the measures from the control ones, while precision, as the dispersion of measurements in each reference parameter. These measurements were carried out using software for analyzing 3-dimensional data. Data analysis software was used for statistical and measurements analysis (α=.05).RESULTS: Significant differences (P<.05) were found depending on the intraoral scanner used. Best trueness values were achieved with iTero Element1 (mean from 10 ± 7 µm to 91 ± 63 µm) while the worst values were obtained with Trios3 (mean from 42 ± 23 µm to 174 ± 77 µm). Trueness analysis in angle measurements, as well as precision analysis, did not show conclusive results.CONCLUSION: iTero Element1 was more accurate than the current versions of Trios3 and True Definition. Importantly, the proposed methodology is considered reliable for analyzing accuracy in any dental arch length and valid for assessing both trueness and precision in an in vivo study.

A retrospective study on the clinical outcomes of all-ceramic crowns restoration fabricated by oral digital impression / 口腔疾病防治

Objective @#To evaluate the clinical outcomes of all-ceramic crowns whose oral digital impressions were scanned by 3Shape Trios. @*Methods @#All the impressions were scanned by Trios and all the crowns were fabricated according to the standard procedure. The restoration quality were evaluated using modified United States Public Health Service (USPHS) criteria one year after treatment. Restoration integrity、 marginal adaptation、enamel wear、 color satisfaction and gingival index (GI) of the prostheses were evaluated according to the modified USPHS criteria. @*Results@#The clinical 1 year survival rate of 92 porcelain crowns fabricated by 3-shape Trios digital impression and made by CAD/CAM was 100%. The scored A rates of restoration integrity、 marginal adaptation、 enamel wear、 secondary caries、color satisfaction and gingival index of the prostheses were 100%、91.3%、 98%、95.6%、96.7% and 94.7% after 1 year, respectively.@*Conclusion@#The clinical outcomes of all-ceramic crowns whose oral digital impressions were scanned by 3Shape Trios and whose crowns were made by CAD-CAM are satisfying.

A retrospective study on the clinical outcomes of all-ceramic crowns restoration fabricated by oral digital impression / 口腔疾病防治

Objective @#To evaluate the clinical outcomes of all-ceramic crowns whose oral digital impressions were scanned by 3Shape Trios. @*Methods @#All the impressions were scanned by Trios and all the crowns were fabricated according to the standard procedure. The restoration quality were evaluated using modified United States Public Health Service (USPHS) criteria one year after treatment. Restoration integrity、 marginal adaptation、enamel wear、 color satisfaction and gingival index (GI) of the prostheses were evaluated according to the modified USPHS criteria. @*Results@#The clinical 1 year survival rate of 92 porcelain crowns fabricated by 3-shape Trios digital impression and made by CAD/CAM was 100%. The scored A rates of restoration integrity、 marginal adaptation、 enamel wear、 secondary caries、color satisfaction and gingival index of the prostheses were 100%、91.3%、 98%、95.6%、96.7% and 94.7% after 1 year, respectively.@*Conclusion@#The clinical outcomes of all-ceramic crowns whose oral digital impressions were scanned by 3Shape Trios and whose crowns were made by CAD-CAM are satisfying.

Comparison of the accuracy of digital impressions and traditional impressions: Systematic review / 대한치과보철학회지

PURPOSE: This study systematically examines literatures on the suitability of prostheses and accuracy of obtained impressions to see if digital impressions using intraoral scanners can replace traditional impressions. MATERIALS AND METHODS: A MEDLINE/PubMed search and manual search was performed for studies written in English about accuracy of digital impression published in dental journals from August 1, 1997, to July 31, 2017. Depending on criteria, the data for the selected articles were independently organized into standardized spreadsheets by 2 reviewers. RESULTS: Among the total 35 studies met the inclusion criteria, there were 26 studies comparing the suitability of prostheses, and 9 studies comparing the accuracy of impressions through scan data without prostheses. Most studies used prostheses to compare the accuracy of impression techniques. CONCLUSION: This review suggests that making single crown or mesio-distally short prostheses with digital impressions is clinically reliable in natural teeth. However, there is still a limit to making mesio-distally long prostheses with digital impressions from the lack of related studies. Digital impression cannot fully replace traditional impressions in implant prostheses yet.

Comparative study on quality of scanned images from varying materials and surface conditions of standardized model for dental scanner evaluation

PURPOSE: The purpose of this study is to evaluate the image acquisition ability of intraoral scanners by analyzing the comprehensiveness of scanned images from standardized model, and to identify problems of the model. MATERIALS AND METHODS: Cast models and 3D-printed models were prepared according to international standards set by ISO12836 and ANSI/ADA no. 132, which were then scanned by model scanner and two different intraoral scanners (TRIOS3 and CS3500). The image acquisition performance of the scanners was classified into three grades, and the study was repeated with varying surface conditions of the models. RESULTS: Model scanner produced the most accurate images in all models. Meanwhile, CS3500 showed good image reproducibility for angled structures and TRIOS3 showed good image reproducibility for rounded structures. As for model ingredients, improved plaster model best reproduced scan images regardless of the type of scanner used. When limited to 3D-printed model, powdered surface condition resulted in higher image quality. CONCLUSION: When scanning structures beyond FOV (field of view) in standardized models (following ISO12836 and ANSI/ADA 132), lack of reference points to help distinguish different faces confuses the scanning and matching process, resulting in inaccurate display of images. These results imply the need to develop a new standard model not confined to simple pattern repetition and symmetric structure.

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.

Reliability study in the measurement of the cusp inclination angle of a chairside digital model / 华西口腔医学杂志

OBJECTIVE@#This study aims to evaluate the reliability of the software Picpick in the measurement of the cusp inclination angle of a digital model.@*METHODS@#Twenty-one trimmed models were used as experimental objects. The chairside digital impression was then used for the acquisition of 3D digital models, and the software Picpick was employed for the measurement of the cusp inclination of these models. The measurements were repeated three times, and the results were compared with a gold standard, which was a manually measured experimental model cusp angle. The intraclass correlation coefficient (ICC) was calculated.@*RESULTS@#The paired t test value of the two measurement methods was 0.91. The ICCs between the two measurement methods and three repeated measurements were greater than 0.9. The digital model achieved a smaller coefficient of variation (9.9%).@*CONCLUSIONS@#The software Picpick is reliable in measuring the cusp inclination of a digital model.

The effects of two different patterns on the precision of zirconia all-ceramic crowns / 口腔疾病防治

Objective@#The objective of this study was to compare the early clinical effects of zirconia all⁃ceramic crowns using two different impression methods. Zirconia ceramic crowns were produced using digital models based on either a silicone rubber impression perfusion model in vitro or a 3D mouth scanner.@*Methods @#A total of 50 patients with a planned restoration of the first permanent molar with zirconia all⁃ceramic crowns after root canal therapy were se⁃ lected and randomly divided into two groups: a digital impression by intraoral 3D scanning group and a digital impres⁃ sion by extraoral scanning after silicone rubber impression group. Zirconia all⁃ceramic crowns were created by CAD/ CAM in both groups. Marginal adaptation, proximal contact, and occlusal contact were compared between groups. @*Results@#There was no significant difference between the two groups in marginal adaptation (P > 0.05). For proximal con⁃ tact and occlusal contact, no significant differences regarding the number of cases for the criteria of level A and level B were found between two groups (P > 0.05), while the misfit value in level B was smaller in the first group than in the second group (P < 0.05). @*Conclusion@#Zirconia all⁃ceramic crowns with intraoral 3D scanning show excellent early clinical performance.

The immediate implant and immediate restoration in the anterior maxilla with the digital technique: case report and literature review / 口腔疾病防治

Objective @#To describe a novel workflow for the anterior dental esthetics in immediate implant and immediate aesthetic restoration with digital technique. @*Methods @#Before the implant placement, a intra-oral optical scan(IOS) combined with CBCT was performed to virtually design the 3D implant position and restoration. A surgical guide and an individualized Ti abutment restoration was CAD/CAM-fabricated out of the PMMA-based in a fully digital workflow and seated at the stage of minimal invasive surgery.@*Results @#The technique achieved immediate implant and immediate restoration after tooth extraction. Immediate restoration of temporary crown could be completed immediately in second patient visit after the operation, finally realized the aesthetic implantation with preserved soft tissue contour. @*Conclusin @# The fully digital technique changed the conventional workflow which achieves more efficiency and better aesthetic effect.

Immediate loading of mandibular single implant by using surgical guide and modeless digital prosthesis: a case report

In this case report, immediate loading of an implant-supported single-tooth prosthesis through complete digital workflow. A patient presented for restoration of missing a single tooth in the mandibular first molar. The digital impression was made with intraoral scanner and implant was placed using surgical guide pre-fabricated with pre-operative computed tomography (CT) and scan data. After 1 week later, prefabricated customized abutment and provisional restoration were connected for immediate loading. After 8 weeks later, abutment level impression was taken by intraoral scanner. At 3 months later from implant installation, monolithic zirconia crown were fabricated. This clinical report presents satisfying result in accuracy and patient satisfaction. A completely modeless digital procedure met expectations regarding precision, esthetics, and functionality.

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.

Comparative analysis on reproducibility among 5 intraoral scanners: sectional analysis according to restoration type and preparation outline form

PURPOSE: The trueness and precision of acquired images of intraoral digital scanners could be influenced by restoration type, preparation outline form, scanning technology and the application of power. The aim of this study is to perform the comparative evaluation of the 3-dimensional reproducibility of intraoral scanners (IOSs). MATERIALS AND METHODS: The phantom containing five prepared teeth was scanned by the reference scanner (Dental Wings) and 5 test IOSs (E4D dentist, Fastscan, iTero, Trios and Zfx Intrascan). The acquired images of the scanner groups were compared with the image from the reference scanner (trueness) and within each scanner groups (precision). Statistical analysis was performed using independent two-samples t-test and analysis of variance (α=.05). RESULTS: The average deviations of trueness and precision of Fastscan, iTero and Trios were significantly lower than the other scanners. According to the restoration type, significantly higher trueness was observed in crown and inlay than in bridge. However, no significant difference was observed among four sites of preparation outline form. If compared by the characteristics of IOS, high trueness was observed in the group adopting the active triangulation and using powder. However, there was no significant difference between the still image acquisition and video acquisition groups. CONCLUSION: Except for two intraoral scanners, Fastscan, iTero and Trios displayed comparable levels of trueness and precision values in tested phantom model. Difference in trueness was observed depending on the restoration type, the preparation outline form and characteristics of IOS, which should be taken into consideration when the intraoral scanning data are utilized.