Conventional Impression Methods Research Articles

In vitro evaluation of the impact of intraoral scanner, scanning aids, and the scanned arch on the scan accuracy of edentulous arches.

To assess the accuracy of complete maxillary and mandibular edentulous arch scans obtained using two different intraoral scanners (IOSs), with and without scanning aids, and to compare these results to those obtained using conventional impression methods. Two IOSs were used (TRIOS 4 [TRI] and Emerald S [EMR]) to scan maxillary and mandibular typodonts. The typodonts were scanned without scanning aids [TRI_WSA and EMR_WSA groups] (n = 10). The typodonts were then scanned under four scanning aid conditions (n = 10): composite markers [TRI_MRK and EMR_MRK groups], scanning spray [TRI_SPR and EMR_SPR groups], pressure indicating paste [TRI_PIP and EMR_PIP groups], and liquid-type scanning aid [TRI_LQD and EMR_LQD groups]. Conventional impressions of both arches were also made using irreversible hydrocolloids in stock trays [IHC] and using polyvinyl siloxane (PVS) impression material in custom trays (n = 10) which were digitized using a laboratory scanner. Using a metrology software program, all scans were compared to a reference scan in order to assess trueness and to each other to assess precision. Trueness and precision were expressed as the root mean square (RMS) of the absolute deviation values and the statistical analysis was modeled on a logarithmic scale using fixed-effects models to meet model assumptions (α = 0.05). The main effect of arch (p = 0.004), scanner (p < 0.001), scanning aid (p = 0.041), and the interaction between scanner and scanning aid (p = 0.027) had a significant effect on mean RMS values of trueness. The arch (p = 0.015) and scanner (p < 0.001) had a significant effect on the mean RMS values of precision. The maxillary arch had better accuracy compared to the mandible. The TRIOS 4 scanner had better accuracy than both the Emerald S scanner and conventional impressions. The Emerald S had better precision than conventional impressions. The scanning spray and liquid-type scanning aids produced the best trueness with the TRIOS 4 scanner, while the liquid-type scanning aid and composite markers produced the best trueness for the Emerald S scanner. The scanned arch and the type of scanner had a significant effect on the accuracy of digital scans of completely edentulous arches. The scanning aid had a significant effect on the trueness of digital scans of completely edentulous arches which varied depending on the scanner used.

Prosthetic Rehabilitation of a Maxillectomy Patient with Restricted Mouth Opening Using an Altered Cast Technique: A Case Report

Deformity in the maxillofacial region caused by surgical resection of a tumor have an adverse effect on the patient's ability to swallow, masticate, phonate, and psychological state. These patients may have restricted mouth opening capacity due to several surgical procedures and scar contracture resulting from radiation therapy. Therefore due to restricted access to the oral cavity prosthetic rehabilitation of these patients becomes a challenging task. A precise impression of the resection defect is necessary for accurate obturation. This is not practical for patients who have restricted mouth opening, hence this crucial first step in the making of a good prosthesis is frequently accomplished by altering the conventional impression method. This clinical report details the prosthetic rehabilitation of a patient who was diagnosed with Adenoid cystic carcinoma of the left maxillary sinus. Patient underwent maxillectomy for tumor removal, which was worsened by trismus as a result of the procedure and radiation therapy. For orofacial rehabilitation and defect obturation, the patient was restored with a removable dental prosthesis with a hollow bulb obturator. An altered cast technique was used in the final impression making. This rehabilitation approach was successful in restoring lost function and appearance of the patient. Keywords: Maxillectomy, Hollow Obturator, Altered cast technique

Evaluation of the accuracy of different digital scanning systems and intraoral scanning strategies: An in vitro study

Abstract Introduction: Differentiating between the various available digital impression systems in terms of accuracy could help in determining the most appropriate system to be used. Aim: The purpose of this in vitro study was to evaluate the accuracy of four different intraoral scanners, along with different intraoral scanning strategies (IOSs), and using the conventional impression method. Materials and Methods: A model with prepared teeth was scanned with a laboratory scanner. Following that, the model was scanned using the following four intraoral scanners (IOSs): TRIOS, CEREC AC Omnicam, Medit i700, and iTero Element 2. Three scanning strategies were used with each scanner during the intraoral scanning (C-motion, zig-zag, and wiggling strategies). Each strategy was repeated eight times resulting in 96 scans, along with eight conventional impressions. All three-dimensional test models were compared with the master model using Geomagic Control X. The master model was trimmed to isolate the teeth and was superimposed with all 104 test models. The data was statistically analyzed using the nonparametrical Kruskal–Wallis test. Results: Statistically significant differences were found when comparing all groups (the four IOSs and the conventional impression method) in terms of trueness and precision (P &lt; 0.001). For trueness, the i700 was the highest ranked IOS (35.68 ± 1.18 μm), excelling in all groups regardless of the strategy used. For precision results, the best IOS was the i700 (46.14 ± 1.43 μm) regardless of the strategy used. Conclusion: Medit’s i700 scanner exhibited better accuracy compared to the other three scanners. Meanwhile, the zig-zag strategy may provide the best scanning accuracy when used with the majority of the scanners.

Patient-reported outcome measures (PROMs) of digital and conventional impression methods for fixed dentures.

Digital impression technique or computer-aided impression (CAI) has been recently concluded as a clinically acceptable alternative to conventional impression method (CIM) in the fabrication of crowns, short fixed partial dentures (FPDs), and implant-supported crowns. The purpose of this study was to investigate the patients' opinion and subjective perception of two different ways of impression - digital and conventional. A total of 45 patients were treated with CAI and CIM for the fabrication of tooth or implant-supported crowns. They fulfilled a questionnaire including 11 questions regarding the treatment time, gag reflex, discomfort related to manipulation, and other aspects of treatment. CAI was considered the preferential method for future treatment in 53% of patients, whereas 28.9% of the respondents preferred CIM. The preference for the impression method was influenced by the total time spent with the procedure, discomfort during manipulation with the tray or scanning head, size of the tray or scanning head, maximal opening discomfort, and (the tendency towards) gag reflex. CAI was considered a more comfortable and preferential method. Discomfort or difficulties during CAI negatively affected the patients' attitude to CAI, whereas the difficulties associated with CIM did not have any influence on the preferred method.

Examination of the effect of aging process on marginal fit and fracture strength of temporary crowns prepared from different materials

AimThe aim of this study is to investigate the effect of the aging process on the marginal fit and fracture resistance of temporary crowns prepared using different materials. Materials and methodThe steel die to represent the maxillary first premolar used in this study was produced on a CNC turning machine to include an anatomical occlusal surface. A total of 160 epoxy resin dies were obtained by taking impressions with conventional impression methods on the metal die. Epoxy resin dies were randomly divided into four groups. Temporary crowns were prepared for each group from poly acrylic resin (Vita CADTemp®), bis-acryl composite resin (Protemp 4), poly methyl methacrylate (PMMA; Imident) and poly ethyl methacrylate (PEMA; Dentalon Plus) restorative materials. Half of the specimens (n = 20) in each group (n = 40) were randomly separated and the aging process was applied 5000 times in the device. Marginal gap measurements on epoxy resin dies were made using a stereomicroscope. The fracture strength test of the specimens was performed by using the Instron Universal Test Device. Jamovi 2.2.5 statistical program was used for statistical analysis. ResultsWhen compared to temporary crowns prepared from all other materials, poly acrylic resin (Vita CADTemp ®) temporary crowns observed significantly lower marginal gap values (59,05 μm) regardless of the aging process, and a significantly higher fracture resistance (478,44 N) in the presence of aging process (p < .05 for each). While the highest marginal gap value was detected in PMMA (Imident) (120.36 μm) temporary crowns with aging process, the lowest marginal gap value was observed in poly acrylic resin (Vita CADTemp®) (59.05 μm) crowns without non-aging process. The marginal fit and fracture resistance of all temporary crowns were negatively affected by the aging process. ConclusionOur findings revealed the superiority of poly acrylic resin (Vita CADTemp®) crowns to the temporary crowns prepared from all other materials in terms of the significantly lower marginal gap in the absence of aging process, and the significantly higher fracture resistance in the presence of aging process. Marginal fit and fracture resistance values for all materials were found to be within clinically acceptable limits.

The effect of cement and impression methods on the marginal and internal adaptation of the current monolithic blocks - 3D scanning evaluation.

This research aimed to evaluate the marginal and internal gaps of crowns, which were produced using both digital and conventional impression techniques and cemented with various types of cement. For the full ceramic crown restoration, an anatomically prepared acrylic first molar phantom tooth (Frasaco GmbH, Germany) was scanned with Scanner S600 ARTI (Zirkonzahn). 160 PMMA analogues produced from the milling unit. Two impression methods were used: digital impressions by intraoral scanner (Aadva Intra Oral 3D Scanner, GC) and PVS impression. Cerasmart, Initial LRF Block, Zirconia Prettau and ICE Zircon monolithic blocks milled with M1 Milling Unit (Zirkonzahn). Restorations cemented with light-cured and dual-cured cements. (n = 10) Pre and post-cementation 3D images overlap was performed using Geomagic Control X (3D Systems, NC, USA). Data were analysed by using SPSS 25.0. p<0.05 difference was considered significant. Digital impressions were significantly higher than PVS impressions in all groups (p<0.05). A significant difference was found between the materials (p<0.05). Cerasmart showed a significantly more marginal gap than the other groups. Prettau and ICE Zircon crowns with the conventional impression group showed a significantly smaller marginal gap than the others. Monolithic crowns fabricated by CAD-CAM using the digital and conventional impression methods had clinically acceptable marginal and internal gaps. Crowns cemented with dual-cured cements showed significantly more marginal gap than light-cure groups. Key words:3D scanning, Marginal accuracy, Marginal fit, Monolithic crown.

Comparative Analysis of Intraoral Scanners and Traditional Impression Methods in Full-Arch Implantology: A Systematic Review

Background: The comparative effectiveness of intraoral scanners (IOS) and conventional impression (CI) methods in full-arch implantology has been a topic of ongoing debate. This systematic review aimed to provide a comprehensive comparison of these methods across different applications and conditions. Methods: This systematic review was conducted in accordance with the PRISMA guidelines, with the search conducted across different online databases and the relevant studies were extracted, following which they underwent bias assessment and their relevance towards this review was examined. Results: Five in-vitro studies, encompassing various types of IOS and CI methods, were systematically reviewed. The review revealed that neither IOS nor CI could be deemed universally superior. Their relative effectiveness varied depending on several factors, including the specific application, the presence or absence of landmarks, and the type of dimensional analysis used. For instance, while digital techniques offered advantages in terms of minimal distortion for tilted implants, conventional methods demonstrated superior trueness in other scenarios. Conclusion: The findings underscored the importance of a context-specific approach in selecting between IOS and CI, thereby guiding clinical practice and informing future research. However, the transferability of the findings to clinical practice may be limited due to the in-vitro study design, the variety of IOS types, the unaccounted influence of operator skill, and the incomplete exploration of the role of landmarks. Future studies should address these limitations to further enhance our understanding of full-arch implantology.

The impact of digitization and conventional techniques on the fit of fixed partial dentures FPDs: systematic review and Meta-analysis

Purpose of the studyThe goal behind this study is to answer the question “In tooth-supported fixed partial dentures (FPDs), does the digital impression techniques compared to fabrications using conventional impression methods improve the marginal and internal fit?BackgroundThe incorporation of digital technology in the fabrication of fixed partial dentures (FPDs) has accelerated over the past decade. This study is directed at evaluating the marginal and internal fit of FPDs manufactured using digital approaches compared to conventional techniques. The need for updated data has encouraged this review.Materials and methodsAn electronic search was conducted in PubMed, Scopus, Web of Science, and the Grey Database to identify relevant studies. The Modified Methodological Index for Non-Randomized Studies (MINORS) was used to assess the risk of bias in in vitro experiments.The key results of this meta-analysis were the standard mean differences (SMDs) and 95% confidence intervals (CI) of each main variance, marginal fit, and internal fit between the digital and conventional techniques.Additional analyses were performed to assess the significance of three subgroup parameters: method of digitalization, cement spacer thickness, and span length, and their influence on the fit of the FPDs.ResultsBased on predefined criteria, of the seven articles included in this systematic review, only five were selected for the quantitative data analysis. The marginal fit results were (P = 0.06; SMD: -1.88; 95% CI: − 3.88, 0.11) (P > 0.05) and the internal fit results were (P = 0.02; SMD: -0.80; 95% CI: − 1.49, − 0.10) (P < 0.05).Regarding the subgroup analyses, the method of digitalization subgroup results were (P = 0.35; SMD: -1.89; 95% CI: − 3.89, 0.11) and (P = 0.80; SMD: -0.80; 95% CI: − 1.49, − 0.11) for marginal and internal fit, respectively. The span length results were (P = 0.10; SMD: -1.89; 95% CI: − 3.89, 0.11) for marginal fit and (P = 0.02; SMD: -0.80; 95% CI: − 1.49, − 0.11) for internal fit. The cement spacer thickness (P = 0.01; SMD: -1.89; 95% CI: − 3.89, 0.11) and (P = 0.04; SMD: -0.80; 95% CI: − 1.49, − 0.11) for marginal and internal fit, respectively.ConclusionTooth-retained fixed partial dentures FPDs produced by digital scanning and computer-aided design/computer-aided manufacturing (CAD/CAM) systems can significantly enhance the internal fit compared with those manufactured by traditional methods.Intraoral scanners can replace conventional impressions for the fabrication of FPDs because they minimize the operating time and reduce patient pain.Further clinical studies are required to obtain more conclusive results.Systematic review registrationThis systematic review and meta-analysis was registered in the International Prospective Register of Systematic Reviews (PROSPERO), registration number CRD42021261397.

Intraoral scanners in children: evaluation of the patient perception, reliability and reproducibility, and chairside time-A systematic review.

The aim of this systematic review is to evaluate the perception of the patient, the chairside time, and the reliability and/or reproducibility of intraoral scanners for full arch in pediatric patients. A data search was performed in four databases (Medline-Pubmed, Scopus, ProQuest and Web of Science) in accordance with the PRISMA 2020 statements. Studies were classified in three categories (patient perception, scanning or impression time and reliability and/or reproducibility). The resources, the data extraction and the quality assessment were carried out independently by two operators. The variables recorded were population characteristics, material and methods aspects and included country, study design and main conclusion. A quality assessment of the selected studies was performed with QUADAS-2 tool, and Kappa-Cohen Index was calculated to analyze examiner agreement. The initial search obtained 681 publications, and finally four studies matching inclusion criteria were selected. The distribution of the studies in the categories was three for the analysis of the patient's perception and scanning or impression time; and two items to assess the reliability and/or reproducibility of intraoral scans. All included studies have a repeated measures-transversal design. The sample size ranged between 26 and 59 children with a mean age. The intraoral scanners evaluated were Lava C.O.S, Cerec Omnicam, TRIOS Classic, TRIOS 3-Cart and TRIOS Ortho. The quality assessment of the studies using QUADAS-2 tool revealed a low risk of bias while evaluating patient perception, but an unclear risk of bias in the analysis of accuracy or chairside time. In relation to the applicability concerns, the patient selection was of high risk of bias. All studies agreed that the patient perception and comfort is better with intraoral scanners in comparison with the conventional method. The accuracy or reliability of the digital procedure is not clear, being clinically acceptable. In relation with the chairside time, it depends on the intraoral scanner, with contradictory data in the different analyzed studies. The use of intraoral scanners in children is a favorable option, finding a significantly higher patient perception and comfort with intraoral scanners compared to the conventional impression method. The evidence for reliability or reproducibility is not strong to date, however, the differences between the intraoral measurements and the digital models would be clinically acceptable.

Conventional and Digital Impressions for Fabrication of Complete Implant-Supported Bars: A Comparative In Vitro Study.

Obtaining accurate models and well-fitting prostheses during the fabrication of complete implant-supported prostheses has been a significant challenge. Conventional impression methods involve multiple clinical and laboratory steps that can lead to distortions, potentially resulting in inaccurate prostheses. In contrast, digital impressions may eliminate some of these steps, leading to better-fitting prostheses. Therefore, it is important to compare conventional and digital impressions for producing implant-supported prostheses. This study aimed to compare the quality of digital intraoral and conventional impressions by measuring the vertical misfit of implant-supported complete bars obtained using both types of techniques. Five digital impressions using an intraoral scanner and five impressions using elastomer were made in a four-implant master model. The plaster models produced with conventional impressions were scanned in a laboratory scanner to obtain virtual models. Screw-retained bars (n = five) were designed on the models and milled in zirconia. The bars fabricated using digital (DI) and conventional (CI) impressions were screwed to the master model, initially with one screw (DI1 and CI1) and later with four screws (DI4 and CI4), and were analyzed under a SEM to measure the misfit. ANOVA was used to compare the results (p < 0.05). There were no statistically significant differences in the misfit between the bars fabricated using digital and conventional impressions when screwed with one (DI1 = 94.45 µm vs. CI1 = 101.90 µm: F = 0.096; p = 0.761) or four screws (DI4 = 59.43 µm vs. CI4 = 75.62 µm: F = 2.655; p = 0.139). Further, there were no differences when the bars were compared within the same group screwed with one or four screws (DI1 = 94.45 µm vs. DI4 = 59.43 µm: F = 2.926; p = 0.123; CI1 = 101.90 µm vs. CI4 = 75.62 µm: F = 0.013; p = 0.907). It was concluded that both impression techniques produced bars with a satisfactory fit, regardless of whether they were screwed with one or four screws.

Effect of inter-dental abutment distance on the impression accuracy of digital and conventional methods.

This study aimed to examine the effect of inter-dental abutment distance on the accuracy of digital and conventional impression methods. Five maxillary and mandibular models were prepared with different inter-dental abutment distances. Digital scans were obtained using an extraoral laboratory scanner as reference data. Each group was scanned 8 times using the intra-oral scanner for the digital method. For the conventional impression method, 8 additional silicone impression material was used to generate the stone casts from each group. Then casts were scanned. In the next step, stereolithography (STL) data was exported from the scans. The STL files were super-imposed on the reference scans using 3shape dental designer software to make the measurement. Kolmogorov-Smirnoff was used to determine if the data were normally distributed. In the digital impression method, as the abutment distance increased, the accuracy decreased. Various inter-dental abutment distances in digital groups showed significant differences (p=0.016) in impression accuracy, while the difference among conventional groups was not statistically significant (p=0.822). In the digital method, the mean inter-dental abutment between the 4-5 and 3-7 groups, 4-6 and 3-7 groups had a significant difference (p<0.05). However, the conventional method revealed no significant differences (p>0.05) between groups. In conclusion, when the inter-dental abutment distance exists and is surrounded by soft tissue, the possibility of error in the digital impression method is higher than in the conventional impression method.

DEVELOPMENTS IN CAD/CAM TECHNOLOGY: POSSIBILITIES FOR DENTAL APPLICATION

Examining CAD/CAM technology and their use in dental treatments is the goal of this study. The computer-controlled technology known as computer-aided design and computer-aided production (CAD/CAM) allows for the design of the material to be generated in 3-dimensions on the computer monitor. Since the 1950s, it's primarily been employed in the aerospace and industrial sectors. The development of CAD/CAM technology in dentistry has made it possible to construct restorations out of high-performance materials that were previously difficult to shape. In the past 20 years, dental CAD/CAM systems have grown in popularity. Since 1984, several CAD/CAM systems have been created, including the Cerec, E4D, Procera, Everest, DCS President, Cercon, and Lava systems. In contrast to conventional impression methods, the advancement of such systems makes it possible to create the restoration in accordance with the features of the restoration and innate dental anatomy, generate the restoration quickly at the patient 's bedside, guarantee the peripheral and inner harmony of the restoration, boost its resistance properties, and offer an improved look and feel.

Evaluation of the accuracy of digital and conventional implant-level impression techniques for maxillofacial prosthesis.

This study aims to evaluate the accuracy of digital impression making based on trueness and precision measurements of dental implants placed in maxillofacial lesions to produce Maxillofacial prosthesis substructures. Two intra-oral scanners (Trios 3 and CS 3700) and one Desktop scanner (open technology) were examined in this study. A Model of a patient with a lesion in the ear region was created as a reference. The reference model was scanned by each scanner 10 times. Standard Tessellation Language files were provided from each scanner and were examined in terms of Trueness and Precision aspects. In Distance 1, in the one-way analysis of variance test, there was a significant difference between the three scanners. The Trios group has less deviation than the Open Technology group (P = 0.015) compared with the CareStream (CS) group that showed more deviation (P < 0.000). There is a statistically significant difference in distance 2 among scanners. The Trios group showed more deviation as compared with the Open Technology group (P < 0.000). While this deviation is not statistically significant compared with the CS group (P = 0.0907). Open Technology Group compared with the CS group also has less deviation in distance 2, which has been statistically significant (P < 0.000). The preparation of a precise model of maxillofacial lesions is still difficult for some Intraoral scanners. There were significant statistical differences in Trueness and Precision among scanners. Used scanners can be applied as an alternative to conventional impression methods.

Evaluation of accuracy of photogrammetry with 3D scanning and conventional impression method for craniomaxillofacial defects using a software analysis

BackgroundFacial mutilation and deformities can be caused by cancer, tumours, injuries, infections, and inherited or acquired deformities and has the potential to degrade one’s quality of life by interfering with fundamental tasks like communication, breathing, feeding, and aesthetics.Depending on the type of defect, producing maxillofacial prostheses for the rehabilitation of patients with various defects can be challenging and complex. The prosthesis is used to replace missing or damaged parts of the cranium and face, like the nose, auricle, orbit, and surrounding tissues, as well as missing areas of soft and hard tissue, with the primary goal of increasing the patient’s quality of life by rehabilitating oral functions such as speech, swallowing, and mastication.Traditional maxillofacial prosthesis impression and fabrication processes include a number of complicated steps that are costly, time-consuming, and uncomfortable for the patient. These rely on the knowledge of the maxillofacial team, dental clinicians, and maxillofacial technician.The foundation of the impression is the keystone for creating a prosthesis. However, this is the most time-consuming and difficult chair-side operation in maxillofacial prosthesis manufacturing since it requires prolonged interaction with the patient. The field of prosthesis fabrication is being transformed by the digital revolution. Digital technology allows for more accurate impression data to be gathered in less time (3 to 5 min) than traditional methods, lowering patient anxiety. Digital impressions eliminate the need for messy impression materials and provide patients with a more pleasant experience. This method bypasses the procedure of traditional gypsum model fabrication. This eliminates the disparity caused by a dimensional distortion of the impression material and gypsum setting expansion. Traditional dental impression processes leave enough room for errors, such as voids or flaws, air bubbles, or deformities, while current technology for prosthesis planning has emerged as an alternative means to improve patient acceptability and pleasure, not only because the end result is a precisely fitted restoration but also because the chair-side adjustments required are reduced.The most frequent approaches for creating 3D virtual models are the following. To begin, 3D scanning is employed, in which the subjects are scanned in three dimensions, and the point cloud data is used to create a virtual digital model.MethodsIt will be a hospital-based randomised control trial, carried out at the Department of Prosthodontics, Sharad Pawar Dental College, Sawangi (Meghe), Wardha, a part of Datta Meghe Institute of Medical Sciences (Deemed University). A total of 45 patients will be selected from the outpatient department (OPD) of the Department of Prosthodontics. All the patients will be provided written consent before their participation in the study.Methodology1. Patient screening will be done, and the patient will be allocated to three techniques that are the conventional manual method, photogrammetry method, and 3D scanning in a randomised manner2. The impression of the defect will be recorded by conventional manual method, photogrammetry method, and 3D scanning3. The defect will be modelled in three ways: first is as per the manual dimension taken on the patient, second is the organisation of photographic image taken with lab standards and third is plotting of point cloud data to generate the virtual 3D model4. For photogrammetric prosthesis design, finite photos/images will be taken at multiple angles to model the 3D virtual design. With the use of minimum photographs, the 3D modelling can be performed by using freeware, and a mould is obtained5. The CAD software was used to design the prosthesis, and the final negative mould can be printed using additive manufacturing6. The mould fabricated by all three methods will be analysed by a software using reverse engineering technologyStudy design: Randomised control trialDuration: 2 yearsSample size: 45 patientsDiscussionRodrigo Salazar-Gamarra1, Rosemary Seelaus, and Jorge Vicente Lopes da Silva et al., in the year 2016, discussed, as part of a method for manufacturing face prostheses utilising a mobile device, free software, and a photo capture protocol, that 2D captures of the anatomy of a patient with a facial defect were converted into a 3D model using monoscopic photogrammetry and a mobile device. The visual and technical integrity of the resulting digital models was assessed. The technological approach and models that resulted were thoroughly explained and evaluated for technical and clinical value.Marta Revilla-León, Wael Att, and Dr Med Dent et al. (2020) used a coordinate measuring equipment which was used to assess the accuracy of complete arch implant impression processes utilising conventional, photogrammetry, and intraoral scanning.Corina Marilena Cristache and Ioana Tudor Liliana Moraru et al. in the year 2021 provided an update on defect data acquisition, editing, and design using open-source and commercially available software in digital workflow in maxillofacial prosthodontics.This research looked at randomised clinical trials, case reports, case series, technical comments, letters to the editor, and reviews involving humans that were written in English and included detailed information on data acquisition, data processing software, and maxillofacial prosthetic part design.Trial registrationCTRI/2022/08/044524. Registered on September 16, 2022

Conventional and digital complete-arch implant impression techniques: An in vitro study comparing accuracy

Statement of problemVarying complete-arch digital-implant–scanning techniques have been described, but their accuracy remains uncertain. PurposeThe purpose of this in vitro investigation was to assess the effect of the implant angulation and impression method (conventional, intraoral digital scan, intraoral scan with a splinting framework, and combining cone beam computed tomography [CBCT] and intraoral scan) on the accuracy of complete arch implant recording. Material and methodsThe following 2 casts were obtained: one with 4 parallel (P group) and the other with 4 angled (up to 30 degrees) implant abutment analogs (NP group). Both the casts were digitized (7Series Scanner) (control file). The following 4 subgroups were created: conventional polyether impression with a splinted framework (CNV subgroup), intraoral scan (IOS subgroup), intraoral scan with a splinting framework (S-IOS subgroup), and intraoral scan combined with CBCT scan (CBCT-IOS subgroup) (n=10). For each file, an implant-supported bar was designed and imported into a program (Netfabb) to perform linear and angular interimplant abutment measurements. Two-way ANOVA (Analysis of Variance) and Tukey tests were selected to examine the data (α=.05). ResultsImplant angulation (P=.010) and impression method (P=.003) significantly influenced the linear trueness. The P group (112 μm) obtained better linear trueness than the NP group (144 μm). The CNV subgroup obtained the best linear trueness, while the IOS and CBCT-IOS showed the worst trueness. Group (P<.001) significantly influenced angular trueness. Group (P=.009) and subgroup (P<.001) influenced the linear precision. The P group (72 μm) obtained better linear precision than the NP group (91 μm). The IOS subgroup obtained the best linear precision. Group (P=.034) significantly influenced the angular precision. The P group (0.46 degrees) had higher angular precision compared with the NP group (0.60 degrees). ConclusionsImplant angulation and the impression methods tested, impacted the accuracy of the complete-arch implant recording. Parallel implants had better trueness and precision values than nonparallel implants. The conventional impression method showed the best trueness and precision. Among the digital implant scan methods assessed, the S-IOS and CBCT-IOS subgroups acquired significantly better trueness and precision than the IOS subgroup.

Effect of the implant-supported provisional restoration on the accuracy of digital peri-implant mucosa replication-A clinical study.

This study aimed to quantitatively evaluate the effect of implant-supported provisional restorations (ISPRs) on the accuracy of the intraoral scanned peri-implant soft-tissue profile in the esthetic area. Sixteen patients with a single ISPR in the maxillary central incisor's region were recruited for this study. Three impression methods were sequentially used in each patient: (1) an intraoral scanning (IOS) with the ISPR, (2) a conventional impression using the ISPR as impression coping, and (3) a routine IOS without the ISPR. The stereolithography files of the three impression methods obtained from the same patient were superimposed, and the conventional impression method was used as the reference model. Two-dimensional (2D) and three-dimensional (3D) analyses were performed to measure the peri-implant soft-tissue deviation between the reference models and IOS from the groups with or without the ISPR, respectively. Data were presented as the means±standard deviations. Two-way analyses of variance with post hoc Sidak's multiple comparisons and paired t-tests were performed for 2D and 3D analyses, respectively. The significance level was set at p<.05. The peri-implant mucosa without the ISPR immediately collapsed (<20s), particularly on the palatine side of the labial mucosa and labial side of the palatine mucosa. Consequently, the IOS without the ISPR led to 414.7±116.0μm of overall dimensional deformation in the cuff-like submucosal region, which was significantly larger (p<.0001) than that in the IOS with the ISPR (230.6±85.5μm). Implant-supported provisional restorations are important for accurate replication of the intraorally scanned peri-implant soft-tissue profile.

Accuracy of the Intra- and Extra-Oral Scanning Technique for Transferring the Intaglio Surface of a Pontic of Provisional Restorations to Definitive Restorations.

When taking the final impression for a three-unit fixed partial denture (FPD), the intaglio surface of the pontic of provisional restoration cannot be transferred accurately to that of definitive restoration. The intra- and extra-oral scanning (IEOS) technique, a method for accurately reproducing the submucosal morphology of the superstructure of an implant, has been reported using an intraoral scanner. In the present study, we evaluated the difference between the conventional impression method using impression material and the IEOS technique in reproducing the morphology of the surface of the pontic of a definitive FPD. There was a significant difference in the trueness of the intaglio surface morphology of the pontic between the conventional method and the IEOS technique; however, no significant difference in precision was observed. As a result, the intaglio surface of the pontic of the three-unit FPD could be transferred to definitive restorations more accurately with the IEOS technique than with the conventional method. These results suggest that the IEOS technique can duplicate the intaglio surface of the pontic more reproducibly to the definitive restorations compared with the conventional method.

Patient-reported experiences and preferences with intraoral scanners: a systematic review.

Intraoral scanners have become an increasingly popular alternative to conventional impression methods. Although their accuracy and validity have been examined thoroughly, patient-reported information including experiences, preferences, and satisfaction has not yet been investigated in a systematic way. The objective of this systematic review is to investigate the available data and appraise the evidence on patient-reported experiences and preferences following impression taking with intraoral scanners. Unrestricted search of seven databases (Pubmed, CENTRAL, Cochrane reviews, Scopus, Web of Science, Clinical Trials, and ProQuest) and grey literature were conducted until October 2020. Detailed search strategies were developed for each database. Studies involving individuals of any gender or age, subjected to full arch impression taking with conventional and intraoral scanning methods were eligible for inclusion. Following the retrieval and selection of the studies, data extraction was performed. Risk of bias assessment was performed using the RoB 2 and ROBINS-I tools. From the initially identified records, nine studies [eight crossover (two of them randomized) and one parallel group] were eventually included in the present systematic review. Randomized studies were shown, overall, to have some concerns regarding bias, whereas the non-randomized studies were found to be at serious risk, mainly because of bias due to confounding. All studies demonstrated some benefit in favour of intraoral scanning compared with conventional techniques. More positive feelings were generally observed with the intraoral scanners regarding smell, taste, sound, vibration, nausea, and queasiness. Overall, comfort assessment mostly favoured digital methods. No differences were found concerning the level of anxiety between the two methods. Among the included studies, time perception was a parameter leading to contradictory results. These emerge due to the nature and characteristics of the information retrieved from the included studies. The validation of the instruments to capture patient-reported outcomes needs to be further elaborated. Intraoral scanners seem to be a promising new asset in the orthodontic office from the perspective of individuals' experiences and preferences. Nevertheless, to investigate patient-reported outcomes correctly, further high-quality studies are required in the future. Open Science Framework (https://osf.io/ayug2/).

Comparison between conventional and digital impression techniques in prosthetic dentistry: a literature review

INTRODUCTION: In modern prosthetic dentistry, there are mainly two approaches when manufacturing any prosthetic restoration: conventional and digital. In these approaches, the methods for reproducing the prosthetic field can be divided into: conventional impression methods, digital impression methods, and combined impression methods. AIM: The aim of the present literature review is to identify the advantages and disadvantages of taking a digital impression over conventional impression, and to determine whether the digital impression is as accurate as a conventional one. MATERIALS AND METHODS: A total of 209 articles were analyzed. The electronic databases of ResearchGate, Embase, Google Scholar, PubMed, and Scopus were used. The search was limited to entire articles written in English and published in peer-reviewed scientific journals. RESULTS: The studied articles were published in the period from 1961 to 2019 and over 60% of them were in the last 10 years. Among these studies, 10 are previous literature reviews, 85 are in vivo clinical trials, 6 are randomized controlled/crossover studies, 11 are controlled comparative studies, 7 are clinical case reports, and 90 are in vitro comparative studies. CONCLUSION: The present study has its limitations due to the fact that it is a literature review. However, we can conclude that the digital impression technique has a number of advantages over the conventional impression technique, one of the most important of which is the reduced patient discomfort.

In Vitro Evaluation of the Marginal and Internal Accuracy of Different Types of Dental Ceramic Restorations Fabricated Based on Digital and Conventional Impressions.

To compare the marginal and internal gap values of different types of ceramic crowns fabricated based on digital and conventional impression 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). 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). 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.