Accuracy Of Digital Impressions Research Articles

The Accuracy of Digital Impressions versus Conventional Impressions in Neonates with Cleft Lip and/or Palate: A Laboratory-Based Study

Cleft lip and palate (CL/P) are a common congenital craniofacial anomaly requiring precise impressions for effective treatment. Conventional impressions (CIs) pose challenges in neonates with CL/P due to their delicate oral anatomy. While digital impressions (DIs) are increasingly recognised for their potential benefits over conventional methods in dentistry, their accuracy and application in neonates with cleft lip and palate (CL/P) remain underexplored. This study aimed to assess the accuracy of DIs compared to CIs in neonates with CL/P, using alginate and putty materials as references. A laboratory-based case–control study was conducted, utilising soft acrylic models resembling neonatal mouths with CL/P. Alginate and putty impressions were obtained conventionally, while digital impressions were captured using an intraoral scanner (IOS). A total of 42 models were analysed, divided evenly into three groups, with each group comprising 14 models. Superimposition and surface discrepancy analyses were performed to evaluate impression accuracy. The results revealed no statistically significant differences between the digital and conventional impressions in their intra-arch measurements and surface discrepancies. The mean measurement values did not significantly differ among groups, with p values indicating no significant variations (p > 0.05), confirmed by an analysis of variance. High intra-examiner reliability with Intra Class Coefficient (ICC) values close to 1 indicated consistent measurements over time. The current study demonstrates that DIs are equally accurate as conventional alginate and putty impressions in neonates with cleft lip and palate, offering a viable and less invasive alternative for clinical practise. This advancement holds promise for improving the treatment planning process and enhancing patient comfort, particularly in vulnerable neonatal populations. Further research is warranted to explore the clinical implications and factors affecting DI accuracy in this population.

The Accuracy of Digital Impressions versus Conventional Impressions in Neonates with Cleft Lip and/or Palate: A Laboratory-Based Study.

Cleft lip and palate (CL/P) are a common congenital craniofacial anomaly requiring precise impressions for effective treatment. Conventional impressions (CIs) pose challenges in neonates with CL/P due to their delicate oral anatomy. While digital impressions (DIs) are increasingly recognised for their potential benefits over conventional methods in dentistry, their accuracy and application in neonates with cleft lip and palate (CL/P) remain underexplored. This study aimed to assess the accuracy of DIs compared to CIs in neonates with CL/P, using alginate and putty materials as references. A laboratory-based case-control study was conducted, utilising soft acrylic models resembling neonatal mouths with CL/P. Alginate and putty impressions were obtained conventionally, while digital impressions were captured using an intraoral scanner (IOS). A total of 42 models were analysed, divided evenly into three groups, with each group comprising 14 models. Superimposition and surface discrepancy analyses were performed to evaluate impression accuracy. The results revealed no statistically significant differences between the digital and conventional impressions in their intra-arch measurements and surface discrepancies. The mean measurement values did not significantly differ among groups, with p values indicating no significant variations (p > 0.05), confirmed by an analysis of variance. High intra-examiner reliability with Intra Class Coefficient (ICC) values close to 1 indicated consistent measurements over time. The current study demonstrates that DIs are equally accurate as conventional alginate and putty impressions in neonates with cleft lip and palate, offering a viable and less invasive alternative for clinical practise. This advancement holds promise for improving the treatment planning process and enhancing patient comfort, particularly in vulnerable neonatal populations. Further research is warranted to explore the clinical implications and factors affecting DI accuracy in this population.

Comparison of Intraoral Scanning Modes in Three Distinct Full- Arch Digital Implant Impression Scenarios: An In Vitro Study.

The purpose of this study was to analyze the effect of scanning modes on the accuracy of the Trios for full-arch digital implant impressions. The trueness and precision of the intraoral scanning mode (IOSM) and the intraoral edentulous scanning mode (IOEM) of the Trios were evaluated in three edentulous models, each featuring 4, 6, and 8 implant analogues. Reference scanning data were obtained by scanning each model with a desktop scanner. Each model was scanned 10 times using the IOSM and IOEM modes of the Trios to establish the test groups. The scan bodies in the test and reference scans were isolated and exported in the reverse engineering program. The scan bodies in each group were superimposed with the corresponding reference scan (trueness) or with each other (precision). The overall 3D deviation between the aligned scan bodies was computed by the root-meansquare (RMS) values. As a result of the trueness and precision evaluation, no significant difference was found between scanning modes in any of the models. When comparing models, the 8-implant model showed significantly lower trueness than the 4-implant model. However, it also exhibited significantly higher precision when compared to both the 4-implant and 6-implant models. There were no significant differences in other pairwise comparisons between the models. Trueness and precision values were similar between the IOSM and IOEM groups across all the models. An increase in the number of implants in complete edentulous arches may have a negative impact on digital impression accuracy.

Effect of different impression coping and scan body designs on the accuracy of conventional versus digital implant impressions: An in vitro study

ObjectivesThis in vitro study compared the accuracy of conventional versus digital impression techniques for angulated and straight implants using two different impression coping and scan body designs. MethodsTwo implant systems were used: Straumann and Dentegris. Two implants were placed for each system, straight and angulated at 15 degrees mesiodistally. Conventional impressions were made using the splinted open-tray technique using narrow impression coping (NIC) and wide impression coping (WIC). The stone casts produced from the conventional impression were digitized with a lab scanner (3Shape D2000). Digital impressions were made using four intraoral scanners (IOS): 3Shape Trios 3, Medit i700, Cerec Omnicam, and Emerald Planmeca using short scanbodies (SSB) and long scanbodies (LSB). The scanning was repeated ten times to generate the Standard Tessellation Language (STL) files. The distance and angle deviations between impression copings and scanbodies were measured in reference to the master model. ResultsThe trueness and precision of SSB and WIC were significantly better than LSB and NIC (p<0.001). The range trueness of the platform deviation was better with SSB (37.1 to 51.9) than LSB (89.6 to 127.9 μm) and for WIC than NIC in conventional impressions (58.2 and 75.1 μm, respectively). The trueness of the angle deviation of digital scans with SSB (0.11 to 0.25 degrees) was significantly better than scans with LSB (0.31 to 0.57 degrees) and for WIC than NIC (0.21 and 0.52 degrees, respectively). The precision of the platform deviation of digital scans with SSB (12.4 to 34.5 μm) was higher than other scans and conventional impressions (42.9 to 71.4 μm). The precision of the angle deviation of Medit i700 and Trios 3 with SSB (0.17 and 0.20 degrees, respectively) was higher than other scans with SSB and conventional impressions (0.54 to 1.63 degrees). ConclusionsDigital scans with SSB were more accurate than conventional splinted open-tray impressions. The type of impression coping and scanbody significantly affected the impression accuracy. Clinical significanceThe use of a short scanbody can increase the accuracy of digital impressions, and wide impression coping can increase the accuracy of conventional impressions, resulting in improved clinical outcomes.

Accuracy of Digital Impression Taking in Partial Dentures: an in Vitro Study on the Degree of Adaptation of Rests

AbstractThe objective of the study is to assess the precision of digital impressions in removable partial dentures through an in vitro study on the degree of abutment adaptation. A Kennedy Class III model with a prosthetic space between elements 43 and 47, featuring niches in the mesio-occlusal and cingulum regions, respectively. Conventional impressions were performed in subgroups CONC and CONM, while digital scanning was conducted in subgroups DIGC and DIGM. Simplified cobalt-chromium alloy frameworks were manufactured using the lost-wax technique on plaster and resin models. The degree of adaptation of the structures was evaluated by impressing the niches with condensation silicone, qualitatively assessing perforations, and quantitatively measuring the mold thickness under a stereomicroscope after cross-sectioning. Regular adaptation was more prevalent among the experimental groups. CONC showed a higher mean degree of abutment adaptation, while CONM had a lower mean. The study factors, impression technique, and type of abutment seat, were not statistically significant, with no interaction among the variables. Occlusal and cingulum abutment measurement points, in both impression techniques, showed no statistically significant difference. Digital scanning yielded better results in terms of abutment adaptation, with smaller average gaps between the abutment seat and the metal structure, making it clinically acceptable. The type of abutment seat and the impression technique did not have a statistically significant impact on abutment adaptation. The impression technique does not represent a factor influencing the adaptation of occlusal and cingulum abutments at different measurement points. Keywords: 3D Printing. Removable Partial Denture. Degree of Adaptation. Rest. ResumoO Objetivo do estudo é valiar precisão da impressão digital em próteses parciais removíveis, por meio de um estudo in vitro sobre o grau de adaptação dos apoios. Um modelo Classe III de Kennedy com espaço protético entre o elemento 43 e 47, nichos na região mésio-oclusal e na do cíngulo. Foram realizadas impressões convencionais nos subgrupos CONC e CONM, e digitalização nos subgrupos DIGC e DIGM, onde estruturas simplificadas de liga de Co-Cr foram fabricadas usando a técnica de fundição perdida nos modelos de gesso e resina. O grau de adaptação das estruturas foi avaliado pela impressão dos nichos com silicone de condensação, qualitativamente as perfurações e quantitativamente a espessura do molde em um estereomicroscópio após seção transversal. A adaptação regular foi mais prevalente entre os grupos experimentais. CONC maior média do grau de adaptação do apoio, enquanto CONM menor média. Os fatores do estudo, técnica de impressão e tipo de assento de apoio, não foram estatisticamente significativos, sem interação entre as variáveis. Pontos de medição de apoio oclusal e de cíngulo, em ambas as técnicas de impressão, sem diferença estatisticamente significativa. A digitalização mostrou melhores resultados em relação ao grau de adaptação dos apoios, com menores lacunas médias entre o assento de apoio e a estrutura metálica, sendo clinicamente aceitável. O tipo de assento de apoio e a técnica de impressão não interferem estatisticamente na adaptação dos apoios. A técnica de impressão não representa um fator que influencie a adaptação de apoios oclusais e de cíngulo em diferentes pontos de medição. Palavras-chave: Impressão 3D. Prótese Parcial Removível. Grau de Adaptação. Apoio.

Influence of scanbody design and intraoral scanner on the trueness of complete arch implant digital impressions: An in vitro study.

This study aimed to compare the accuracy of full-arch digital implant impressions using seven different scanbodies and four intraoral scanners. A 3D-printed maxillary model with six implants and their respective multi-unit abutments was used for this study. Seven scanbodies (SB1, SB2, SB3, SB4, SB5, SB6, and SB7) and four intraoral scanners (Primescan®, Omnican®, Trios 3®, and Trios 4®) were assessed. Each combination group was scanned ten times and a dental lab scanner (D2000, 3Shape) was used as a reference. All scans were exported as STL files, imported into Convince software (3Shape) for alignment, and later into Blender software, where their 3D positions were analyzed using a Python script. The 3D deviation, angular deviation, and linear distance between implants #3 and #14 were also measured. Accuracy was measured in terms of "trueness" (scanbody 3D deviation between intraoral scan and desktop scan). Kruskal-Wallis followed by the Bonferroni correction was used to analyze the data (⍺ = .05). The study found statistically significant differences in digital impression accuracy among the scanners and scanbodies (p<0.001). When comparing different intraoral scanners, the Primescan system showed the smallest 3D deviation (median 110.59 μm) and differed statistically from the others, while Trios 4 (median 122.35 μm) and Trios 3 (median 130.62 μm) did not differ from each other (p = .284). No differences were found in the linear distance between implants #3 and #14 between Trios 4, Primescan, and Trios 3 systems. When comparing different scanbodies, the lowest median values for 3D deviation were obtained by SB2 (72.27μm) and SB7 (93.31μm), and they did not differ from each other (p = .116). The implant scanbody and intraoral scanner influenced the accuracy of digital impressions on completely edentulous arches.

The Accuracy of Full-Arch Intraoral Optical Impressions (IOS): Clinical Pilot Study of the Influence of the Scan Strategy, Operator, and Intraoral Scanner.

To investigate the influence of a novel scanning strategy-using two new intraoral scanner devices with different operators-on the full-arch scanning accuracy for a dentate maxilla. Two scanning strategies, a test and a control strategy, were used to produce full-arch impressions of the dentate maxilla of a study patient. Two intraoral scanning (IOS) devices were used. Five expert operators performed a total of 40 scans. The scan time was recorded for each. A reference model was obtained from the patient's maxillary arch with an analog impression. The model was later scanned with a high-precision laboratory scanner to create a digital reference model (DRM). The scanning accuracy was analyzed with 3D-analysis software using a root mean square (RMS) calculation method, and qualitative analysis was executed using machine learning software. The mean RMS result for the test strategy was 82.8 ± 16 μm compared to 81.5 ± 16 μm for the control strategy. The mean RMS results were 84.7 ± 15 μm for Primescan (PS) and 79.6 ± 17 μm for 3Shape (3S). As such, the scanning strategies and IOS devices did not influence the scanning accuracy. Yet, a significant difference was found when the two strategies' scanning times were compared (P = .001), as well as the IOS devices (P = .001). The operator was found to have no influence on the scanning strategy. The accuracy of digital impressions is not influenced by different strategies, devices, or operators, in contrast with the scanning time, which is influenced by both strategies and devices.

Investigation of the effects of arch size and implant angulation on the accuracy of digital impression using two intraoral scanners: An in vitro study.

The aim of this in vitro study was to evaluate the effect of arch size and implant angulation on the accuracy of digital impression in two intraoral scanners of Trios (3shape) and CEREC (Omnicam). Four acrylic models each including six implants at sites 11, 12, 15, 17, 23, and 27 were used, including large with parallel implants, large with angled implants, small with parallel implants, and small with angled implants. After tightening the scan bodies, distance measurements were done using a coordinate measuring machine. Then, each model was scanned 10 times using each scanner. Trueness and precision measurements were finally computed. The trueness values ranged from 20 to 260 μm in CEREC Omnicam, and from 40 to 1030 μm in Trios. The precision values ranged from 30 to 190 μm in CEREC Omnicam, while from 50 to 770 μm in Trios. The multivariate test analysis indicated that the measured distances via two scanners and different models show different behaviors. Pairwise interactions between these three variables were significant (p < .05). Pairwise interactions between these variables were also significant. (p < .0001). Arch width could affect the accuracy of digital impression; by rotating toward the second quadrant and end points of the scan, errors have increased. However, the angulation of the implants had no effect on the accuracy of digital impression. The CEREC Omnicam scanner showed higher accuracy (trueness and precision) compared to the Trios (3shape) one.

Could various angulated implant depths affect the positional accuracy of digital impressions? An in vitro study.

The purpose of this in vitro investigation was to assess how implant depth could affect the three-dimensional positional accuracy of digital impressions made from angulated implants. Four modified maxillary models were printed and divided into four study groups. In each model, two angulated implant analogs were placed at the sites of the first premolar and first molar at four different depths of 1 (G1), 2 (G2), 3 (G3), and 4 (G4) mm from the models' edentate area. Scan bodies were connected to the analogs, and one operator made 10 full-arch scans for each master model using an intraoral scanner. Afterward, the marginal gingival part of all models was removed, and digital scans were performed for each model using a laboratory scanner to achieve a reference STL file as the control group. One-way ANOVA and Leven's tests were used to measure and compare the 3D distance deviations across research groups after the superimposing test and control scans. A significant difference between research groups was revealed by trueness and precision analysis (p<0.001). The trueness and precision results obtained for G1 and G4 were significantly better than those for G2 and G3 (p<0.05). This study demonstrated that implant depth could affect the digital implant impressions' 3D positional accuracy.

Validation of Digital Impressions' Accuracy Obtained Using Intraoral and Extraoral Scanners: A Systematic Review.

At present, the evidence regarding digital impressions' accuracy recorded by using digital scanners is lacking. This systematic review aimed to evaluate whether the type of scanning (intraoral/extraoral) affects the Accuracy of Digital Impressions. Two independent reviewers performed a systematic search in the database both electronically and manually (PubMed, Ebsco HOST, the Cochrane Library, and Google Scholar) for articles published from 1 January 2010 to 1 December 2022. This study was registered with the International Prospective Register of Systematic Reviews (PROSPERO CRD42020188765) and followed the PRISMA statement. The question in focus was as follows: Does the type of scanning (intraoral or extraoral) affect the accuracy of digital impression? A total of 449 papers were obtained by searching electronically and manually. In total, 15 complete-text papers qualified for assessment based on eligibility criteria. After reading the full-text articles, five studies were excluded. Ten studies were selected for the qualitative analysis. The qualitative data reported that the accuracy of both types of scanners (intraoral and extraoral) lies within the range of clinical acceptability. Nevertheless, the intraoral scanners seem to be more accurate when compared to the extraoral scanners for a partial arch situation. Scanning type affects the accuracy of the digital impression. Various factors influence the scanning ability. Intraoral scanners seem to be more accurate compared to extraoral scanners for a partial arch situation. More studies comparing the accuracy of the intraoral scanner and extraoral scanner for a complete arch scan and in an in vivo study setting are needed.

Effects of scan body number on digital impression accuracy

Effects of scan body number on digital impression accuracy

Influence of Implant Adjacent Teeth on the Accuracy of Digital Impression.

The aim of this study was to evaluate the effect of adjacent teeth patterns on the accuracy of digital scans of parallel and divergent implants for three-unit prostheses. A maxillary typodont model with implants in the locations of the first premolars and first molars was used to develop three clinical scenarios for three-unit prostheses: (S1) Partially edentulous arch with missing first premolars and first molars only; (S2) partially edentulous arch with missing first premolars, second premolars and first molars; and (S3) partially edentulous arch with missing canines, first premolars, second premolars, first molars, and second molars. On one side, the implants were parallel, and for the other side, the implants had a 15-degree buccolingual angle. With the aid of scan bodies, 10 digital impressions were taken for each scenario and for each side. To evaluate the accuracy, a reverse engineering software was used to measure trueness, precision, and interimplant distance. The best trueness for parallel implants was observed for S2 (30.0 µm), followed by S3 (67.3 µm) and S1 (74.8 µm) (p < 0.001). Likewise, S2 had the best precision for parallel implants (31.3 µm) followed by S3 (38.0 µm) and S1 (70.3 µm) (p < 0.001). For the divergent implants, S2 exhibited the best trueness (23.1 µm), followed by S3 (48.2 µm) and S1 (59.4 µm) (p = 0.007). Similarly, the S2 had the best precision (12.3 µm) followed by S3 (62.1 µm) and S1 (66.9 µm) (p < 0.001). The S2 had the least interimplant distance deviation followed by S1 and S3. The difference was significant for parallel implants (p = 0.03), but insignificant for divergent implants (p = 0.15). Regardless of the presenting scenario, digital implant impressions for three-unit prostheses appear to be clinically accurate. A clear interimplant area between scan bodies enhanced the accuracy of digital impressions. This observation can be attributed to more accessible axial surface scanning of the scan body.

Clinical Comparative Study for Validation of Digital Impression Reliability with the Gypsum Check: A Simple and Fast Way to Evaluate the Trueness and Accuracy of Implant-Supported Rehabilitation

Despite many advantages, digital impressions, when compared to the conventional one, produce contrasting results and their complete substitution is still under debate. This comparative study aims to test a way to perform a clinical evaluation of digital impression Accuracy and Trueness with a gypsum check. After calculating the Trueness, Precision, and Accuracy of the digital impressions, a gypsum check was fabricated and screwed on implant abutments. The impression was not considered reliable if the gypsum check fractured during the insertion. The gypsum check test was correlated to a cut-off of 100 µm Trueness. Mean Trueness was 151.19 ± 37.23 µm of the first optical impression and 125.47 ± 41.90 µm of the second optical impression. The Precision mean was 39.76 ± 10.89 µm. The mean Accuracy percentage was 98.69 ± 0.29%. The gypsum checks fractured 10 times on 42 tests, and in any case, the Trueness value was above the 100 µm cut off, with a p = 0.001. A gypsum check screwed onto an implant abutment could be considered a way to perform clinical measurement of Trueness, allowing the clinician to understand if the Trueness value is higher or lower than 100 µm and reflecting the reliability of digital impressions.

Techniques to Improve the Accuracy of Intraoral Digital Impression in Complete Edentulous Arches: A Narrative Review

Complete edentulous arches have been considered as one of the main limitations of intraoral scanners (IOSs). In these clinical scenarios, the accuracy of IOSs can be reduced because of several anatomical factors. To overcome these limitations, some studies have proposed several techniques to increase the accuracy of the impressions by means of various materials and instruments. The aim of this narrative review was to describe these techniques and to compare the obtained results to understand if it is currently feasible to increase the accuracy of the digital impressions of complete edentulous arches. An accurate analysis of the literature was performed using PubMed (National Library of Medicine) as well as manual searching without time and language restrictions. The results showed that there are few articles in the indexed literature on this topic, and that all are in vitro studies. Although the results of the analyzed studies were encouraging and reported useful in vitro results for artificial landmarks as well as for the use of an auxiliary geometry part related to the splinting of intraoral scan bodies (ISBs), clinical trials are needed to confirm that these techniques are feasible in daily clinical practice.

Influence of the implant scan body modifications on trueness of digital impressions

Background/purposeEffects of implant angulation on digital impression accuracy remain controversial. The purpose of this study was to assess the relationship between the alteration of implant scan bodies and the trueness of digital impressions. Materials and methodsA maxillary typodont without the right premolars and first molar was scanned with a laboratory scanner and saved as a standard triangular language (STL) file. A model from the STL file was fabricated with a 3-dimensional printer. Two implants were placed into the first premolar and first molar sites of the model, followed by the insertion of two scan bodies onto the implants. These scan bodies were divided into four test groups, based on the surface modifications. A digital impression of each typodont was made with three different intraoral scanners. An abutment was digitally seated on each implant. 120 STL files (30 for each group) of the typodont with two implants and two corresponding abutments were used for statistical analysis. ResultsA total of 240 values (two implants for each typodont) were obtained after each sample (4 groups) was scanned 10 times by utilizing three intraoral scanners. The overall linear and angular discrepancies were analyzed. Group 1 showed the lowest linear discrepancy of 14.9 ± 5.4 μm while Group 4 reported the highest linear discrepancy of 137.5 ± 41.7 μm, yielding a statistical significance (P < 0.05). ConclusionIt has been concluded that the more adjustments made to the scan bodies, the greater the linear and angular deviations occur, compromising the trueness of the digital implant impression.

ACCURACY OF DIGITAL IMPRESSIONS - A REVIEW

To simplify the oral rehabilitation procedure, digital techniques like intra oral scanners and extra oral scanners have been introduced in dentistry for impression making. Dental impressions, whether traditional or digital, are primarily used to get an impression of one or more prepared teeth, as well as neighbouring and antagonist teeth and inter occlusal relationship.

Analysis of the impact of various finish line designs and occlusal morphologies on the accuracy of digital impressions

Background/purposeRecent advancements in dental technology has led clinicians to convert from traditional methods to digital workflows. The purpose of this study was to analyze the effect of various finish line designs and occlusal morphologies on the accuracy of digital impressions. Materials and methodsSix maxillary molar crown preparations were designed by using a digital sculpting software program. The samples differed in finish line design and occlusal surface morphology. Three different finish line designs (shoulder, chamfer, and shoulder with internal round angle) and two different occlusal morphologies (sharp and rounded) were used, giving six groups. Using three different intraoral scanners, each group was scanned and compared with a reference scan obtained from an industrial scanner. The accuracy of each scan was studied, and the data were statistically analyzed. ResultsA total of 180 scans were acquired by utilizing three different intraoral scanners. The reference scan was compared with the scans from each group and overall differences (marginal, axial, and occlusal) were assessed. A crown preparation with a chamfer finish line showed the lowest marginal discrepancy of 13.2 ± 4.18 μm while preparation with a shoulder finish line reported the highest discrepancy of 34.8 ± 7.9 μm (P < 0.05). Also, the occlusal discrepancies of the samples with rounded and sharp occlusal morphologies were 12.55 ± 3.09 μm and 19.13 ± 2.3 μm, respectively (P < 0.05). ConclusionIt has been suggested that chamfer finish line design and rounded occlusal anatomy may produce more accurate digital impression for single crown restorations.

Accuracy of digital impressions for implant-supported complete-arch prosthesis when using an auxiliary geometry device

Background/purposeDigital impressions using intraoral scanners have recently gained popularity. The aim of the present study was to evaluate the fit of full-arch screw-retained cobalt-chromium frameworks fabricated via two different digital impression methods. Materials and methodsAn edentulous resin master model with four dental implants was fabricated. Forty cobalt-chromium superstructures were fabricated and evaluated according to four groups. In Group 1, the superstructures were evaluated using an intraoral scanner to generate digital impressions. Group 2 relied on the help of an auxiliary geometric appliance in generation of digital impressions via intraoral scanner. The traditional method of splinted open-tray conventional impressions was designated for Group 3. Finally, the control group (Group 4) relied on scanning of the master model directly with a laboratory scanner. Vertical marginal discrepancy was evaluated, and data obtained were statistically analyzed. ResultsThe highest mean vertical marginal gap value (80.86 ± 50.06 μm) was observed for Group 1 and statistically higher than Group 2, 3, and 4 (P < 0.05). The lowest mean vertical marginal gap value (41.98 ± 26.33 μm) was measured from Group 4 and statistically similar to Group 2 and 3 (P > 0.05). ConclusionIt has been suggested that the use of auxiliary geometric appliances yields increased scanning accuracy. Frameworks fabricated using the traditional splinted open-tray technique were more reliable compared to those frameworks from digital impressions.

Effect of abutment tooth location on the accuracy of digital impressions obtained using an intraoral scanner for removable partial dentures.

To verify the effect of abutment tooth location on the accuracy of digital impressions obtained using an intraoral scanner (IOS) for removable partial dentures (RPDs). The target abutment teeth included the left first premolar (#34), second molar (#37), and right second premolar (#45) in a mandibular Kennedy class II model and the left and right second molars (#37, #47) in a class III model. Only #37 was isolated from the remaining teeth by the mucosal area in both models. Digital impressions were obtained using a desktop scanner (reference data) and an IOS (IOS data; scanning origin #37; n=10). The general trueness based on the entire model superimposition (TG), local trueness (TL) of an individual tooth, and dimensional accuracy (coordinate and linear accuracy) of the IOS data of the target abutment teeth were compared (α=0.05). In both models, #37 showed significantly inferior TG (P<0.01), superior TL (P<0.01), and mesial coordinate displacement (P<0.01 and P<0.05 in class II and III models, respectively). Intra-model comparisons showed that #45 in the class II model and #47 in the class III model had significantly inferior linear accuracy (P<0.05 and P<0.01, respectively) and buccal coordinate displacement (P<0.05 and P<0.01, respectively) compared with the other target teeth. In digital impressions of RPDs, isolation of abutment teeth by mucosal areas can reduce general trueness based on the entire dental arch and mesial tooth displacement, whereas increased distance from the scanning origin can adversely affect local trueness and dimensional accuracy.

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.