Mechanical Analysis and Clinical Application of Butterfly-Shaped Patellar Claw.

Memory alloy patella claws for treating patella fractures have been used for more than 30 years with many desirable features including fast healing, quick recovery, and avoidance of top abrasion of Kirschner wires and other complications. However, there are many models and it is difficult to choose the accurate claw for the patient. In this study, a finite element model of the butterfly-shaped patellar claw made of shape memory alloy was established, its mechanical structure was analyzed, and its clinical application was monitored. We used Solidworks Simulation software for modeling and mainly analyzed the force of the compression ring of the butterfly-shaped patellar claw. Clinically, we chose a closed fresh patella fracture case. After finite element analysis, the maximum stress that the compression ring of the butterfly-shaped patellar claw can withstand is 568.1 MPa. In this range, it always has elastic deformation resistance. The butterfly-shaped patella claw is fixed on the patella and will not break when subjected to a maximum force of 150 N on the encircling arm, and at the same time, there will be no pressure failure due to plastic deformation. A total of 27 cases were clinically used for the assessment of the clinical efficacy of the newly designed butterfly-shaped patella claws. The average follow-up time was 15.5 months, and the average fracture healing time was 8-12 weeks. All patients can get out of bed with crutches within 2 to 3 days after surgery. Among them, there were 15 cases with excellent functional ratings, 10 cases with good ratings, 2 cases with acceptable ratings, and no cases with poor ratings. The designed butterfly-shaped patella claws can provide an effective method for the treatment of patella fractures.

Computer aided drug discovery review for infectious diseases with case study of anti-Chagas project.

Neglected tropical diseases (NTDs) are parasitic and bacterial infections that are widespread, especially in the tropics, and cause health problems for about one billion people over 149 countries worldwide. However, in terms of therapeutic agents, for example, nifurtimox and benznidazole were developed in the 1960s to treat Chagas disease, but new drugs are desirable because of their side effects. Drug discovery takes 12 to 14 years and costs $2.6 billon dollars, and hence, computer aided drug discovery (CADD) technology is expected to reduce the time and cost. This paper describes our methods and results based on CADD, mainly for NTDs. An overview of databases, molecular simulation and pharmacophore modeling, contest-based drug discovery, and machine learning and their results are presented herein.

Diversifying chemical libraries with generative topographic mapping.

Generative topographic mapping was used to investigate the possibility to diversify the in-house compounds collection of Boehringer Ingelheim (BI). For this purpose, a 2D map covering the relevant chemical space was trained, and the BI compound library was compared to the Aldrich-Market Select (AMS) database of more than 8M purchasable compounds. In order to discover new (sub)structures, the "AutoZoom" tool was developed and applied in order to analyze chemotypes of molecules residing in heavily populated zones of a map and to extract the corresponding maximum common substructures. A set of 401K new structures from the AMS database was retrieved and checked for drug-likeness and biological activity.

BRADSHAW: a system for automated molecular design.

This paper introduces BRADSHAW (Biological Response Analysis and Design System using an Heterogenous, Automated Workflow), a system for automated molecular design which integrates methods for chemical structure generation, experimental design, active learning and cheminformatics tools. The simple user interface is designed to facilitate access to large scale automated design whilst minimising software development required to introduce new algorithms, a critical requirement in what is a very fast moving field. The system embodies a philosophy of automation, best practice, experimental design and the use of both traditional cheminformatics and modern machine learning algorithms.

Focused Library Generator: case of Mdmx inhibitors.

We present a Focused Library Generator that is able to create from scratch new molecules with desired properties. After training the Generator on the ChEMBL database, transfer learning was used to switch the generator to producing new Mdmx inhibitors that are a promising class of anticancer drugs. Lilly medicinal chemistry filters, molecular docking, and a QSAR IC50 model were used to refine the output of the Generator. Pharmacophore screening and molecular dynamics (MD) simulations were then used to further select putative ligands. Finally, we identified five promising hits with equivalent or even better predicted binding free energies and IC50 values than known Mdmx inhibitors. The source code of the project is available on https://github.com/bigchem/online-chem.

Prediction of formation force during single-point incremental sheet metal forming using artificial intelligence techniques.

Single-point incremental forming (SPIF) is a technology that allows incremental manufacturing of complex parts from a flat sheet using simple tools; further, this technology is flexible and economical. Measuring the forming force using this technology helps in preventing failures, determining the optimal processes, and implementing on-line control. In this paper, an experimental study using SPIF is described. This study focuses on the influence of four different process parameters, namely, step size, tool diameter, sheet thickness, and feed rate, on the maximum forming force. For an efficient force predictive model based on an adaptive neuro-fuzzy inference system (ANFIS), an artificial neural network (ANN) and a regressions model were applied. The predicted forces exhibited relatively good agreement with the experimental results. The results indicate that the performance of the ANFIS model realizes the full potential of the ANN model.

Longitudinal Analysis of CAD/CAM Restoration Incorporation Rates into Navy Dentistry.

INTRODUCTION: Computer-aided design/computer-aided manufacturing (CAD/CAM) has gained increasing popularity since the first commercially viable dental system was introduced in the mid-1980s. Digitally milled dental restorations can be fabricated chairside in the course of one dental appointment, reducing time, cost, and manpower when compared with traditional laboratory-fabricated analog restorations. Clinical performance, physical properties, and esthetics of digital restorations have been shown to be comparable to traditional analog restorations. The Navy has incorporated CAD/CAM systems into dental clinics on multiple platforms to include ships. The efficiency of this technology has the potential to positively impact dental health and mission readiness. The objective of the present study was to evaluate placement rates of CAD/CAM restorations by Navy dental providers. MATERIALS AND METHODS: Placement rates of CAD/CAM restorations from October 2011 to June 2017 (Department of Defense created codes specific to CAD/CAM restorations in 2011) and of laboratory-fabricated analog restorations from January 2008 to June 2017 were queried from the Dental Common Access System (DENCAS) and Corporate Dental Access system (CDA) and evaluated. Scatterplots for each dental restoration category were generated using monthly production data and overlaid with simple linear regression lines and 95% confidence intervals. Regression analysis was performed to determine whether changes in the monthly percentages of placements before and after CAD/CAM were increasing or decreasing and to determine whether the monthly percent change from before CAD/CAM implementation and after CAD/CAM implementation was significantly different from one another. RESULTS: A total of 20,512 CAD/CAM restorations were placed by Navy providers over the 68-month period. A year-over-year increase in digitally fabricated restorations was observed. As a percentage of total indirect restorations, CAD/CAM units surged from 13.8% in 2012 to 38.1% in 2017. All ceramic restorations fabricated by the classical analog method also increased significantly through the period. Traditional analog porcelain fused to metal (PFM) restorations and large amalgam restorations, which frequently serve a similar clinical purpose as indirect or direct full or partial tooth coverage restorations, both decreased significantly after CAD/CAM productivity tracking was initiated. CONCLUSIONS: Implementation of CAD/CAM digital restorations has led to a significant decline in specific traditional analog procedures since productivity tracking of CAD/CAM was initiated in 2011. Navy dentistry has embraced CAD/CAM as an efficient means to prepare sailors and marines for deployments, improve operational dental readiness, and potentially decrease dental emergencies by reducing the need for provisional restorations. The trend toward increased utilization of digital dentistry is expected to continue for the following reasons: (1) incorporation of CAD/CAM technology into dental school curricula, (2) advancement of CAD/CAM systems equipped with fast-evolving user interfaces, (3) increased accessibility to CAD/CAM technology in Navy clinics, and (4) training of a greater proportion of dentists in digital CAD/CAM technology. Future studies should investigate the survival rate of CAD/CAM restorations placed within military settings, cost, and manpower of maintaining CAD/CAM units, and impact on military dental laboratories associated with increased CAD/CAM usage.

Surgery of complex craniofacial defects: A single-step AM-based methodology.

BACKGROUND AND OBJECTIVE: The purpose of the present paper is to pave the road to the systematic optimization of complex craniofacial surgical intervention and to validate a design methodology for the virtual surgery and the fabrication of cranium vault custom plates. Recent advances in the field of medical imaging, image processing and additive manufacturing (AM) have led to new insights in several medical applications. The engineered combination of medical actions and 3D processing steps, foster the optimization of the intervention in terms of operative time and number of sessions needed. Complex craniofacial surgical intervention, such as for instance severe hypertelorism accompanied by skull holes, traditionally requires a first surgery to correctly "resize" the patient cranium and a second surgical session to implant a customized 3D printed prosthesis. Between the two surgical interventions, medical imaging needs to be carried out to aid the design the skull plate. Instead, this paper proposes a CAD/AM-based one-in-all design methodology allowing the surgeons to perform, in a single surgical intervention, both skull correction and implantation. METHODS: A strategy envisaging a virtual/mock surgery on a CAD/AM model of the patient cranium so as to plan the surgery and to design the final shape of the cranium plaque is proposed. The procedure relies on patient imaging, 3D geometry reconstruction of the defective skull, virtual planning and mock surgery to determine the hypothetical anatomic 3D model and, finally, to skull plate design and 3D printing. RESULTS: The methodology has been tested on a complex case study. Results demonstrate the feasibility of the proposed approach and a consistent reduction of time and overall cost of the surgery, not to mention the huge benefits on the patient that is subjected to a single surgical operation. CONCLUSIONS: Despite a number of AM-based methodologies have been proposed for designing cranial implants or to correct orbital hypertelorism, to the best of the authors' knowledge, the present work is the first to simultaneously treat osteotomy and titanium cranium plaque.

A Soft Tooling Process Chain for Injection Molding of a 3D Component with Micro Pillars.

The purpose of this paper is to present the method of a soft tooling process chain employing Additive Manufacturing (AM) for fabrication of injection molding inserts with micro surface features. The Soft Tooling inserts are manufactured by Digital Light Processing (vat photo polymerization) using a photopolymer that can withstand relatively high temperaturea. The part manufactured here has four tines with an angle of 60°. Micro pillars (Ø200 µm, aspect ratio of 1) are arranged on the surfaces by two rows. Polyethylene (PE) injection molding with the soft tooling inserts is used to fabricate the final parts. This method demonstrates that it is feasible to obtain injection-molded parts with microstructures on complex geometry by additive manufactured inserts. The machining time and cost is reduced significantly compared to conventional tooling processes based on computer numerical control (CNC) machining. The dimensions of the micro features are influenced by the applied additive manufacturing process. The lifetime of the inserts determines that this process is more suitable for pilot production. The precision of the inserts production is limited by the additive manufacturing process as well.

Evaluating manufacturing process profile comparability with multivariate equivalence testing: Case study of cell-culture small scale model transfer.

This article studies the Generalized Mahalanobis Distance (GMD) approach proposed by Hoffelder which measures the dissimilarity of two multivariate Gaussian distributions with arbitrary covariance matrices and unequal sample sizes. This investigation demonstrated that, with appropriate adjustment, the GMD approach can achieve the targeted nominal Type I error and provide sufficient power for testing equivalence between two profile populations. The adjusted GMD approach was applied to examine the equivalence of harvest profiles between a 12L small scale model and 2000L manufacturing scale in a transfer study performed at Sanofi Specialty Care Framingham Biologics. The harvest profiles were evaluated based on three critical parameters (Productivity, Lactate Production, and Total Cell Density) and deemed practically equivalent using a pre-defined equivalence margin per the adjusted GMD approach. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:187-195, 2018.

Computational drug discovery for the Zika virus

Few Zika virus (ZIKV) outbreaks had been reported since its first detection in 1947, until the recent epidemics occurred in South America (2014/2015) and expeditiously became a global public health emergency. This arbovirus reached 0.5-1.3 million cases of ZIKV infection in Brazil in 2015 and rapidly spread in new geographic areas such as the Americas. Despite the mild symptoms of the Zika fever, the major concern is related to the related severe neurological disorders, especially microcephaly in newborns. Advances in ZIKV drug discovery have been made recently and constitute promising approaches to ZIKV treatment. In this review, we summarize current computational drug discovery efforts and their applicability to discovery of anti-ZIKV drugs. Lastly, we present successful examples of the use of computational approaches to ZIKV drug discovery.

Integration of Digital Dentistry into a Predoctoral Implant Program: Program Description, Rationale, and Utilization Trends.

A recently revised predoctoral implant curriculum at the University of Illinois at Chicago College of Dentistry integrated digital dentistry into both the preclinical dental implant course and clinical activities. Traditionally, competence in the didactic and clinical parts of predoctoral education in single tooth implant restorations has emphasized the analog impression technique and subsequent mounting of soft tissue working casts. However, computer-aided design/computer-aided manufacturing (CAD/CAM) implant restorations can play a significant role in predoctoral dental education utilizing digital technologies. The goal of the curriculum expansion is to transition from analog to partially digital and, finally, complete digital workflow. The aim of this article is to describe the specific components, implementation, and rationale for the new digitally integrated implant curriculum and present short-term clinical utilization trends.

Survey on the use of CAD-CAM technology by UK and Irish dental technicians.

Statement of the problem Digital workflows (CAD/CAM) have been introduced in dentistry during recent years. No published information exists on dental technicians' use and reporting of this technology.Purpose The aim of this cross sectional survey was to identify the extent digital technology has infiltrated the workplace and to investigate the factors affecting the use of CAD-CAM technology by dental laboratory technicians within Ireland and the UK.Materials and methods A web-based questionnaire was composed (Opinio, Object Planet Inc. Oslo, Norway) and distributed to UK and Irish dental technicians. Answers to all questions were anonymous and grouped such that general information was gathered initially, followed by branching of the survey into two sections depending on whether or not the respondent worked with CAD-CAM technology. Results were compiled and statistical analysis (Fisher's Exact test, SPSS, IBM, Armonk, New York, USA) was performed in order to investigate any correlation between various demographic variables and the answers provided.Results The survey was distributed to 760 UK technicians and 77 Irish technicians. The total number of completed surveys was 105, which yielded a total response rate of 14%. Most technicians reported using some form of CAD/CAM aspect in the workflow, and this was more significant for technicians working in large laboratories. Most training received was company-led. Large laboratories were also significantly correlated with less outsourcing of CAD/CAM work and a change in dental material use leading to the increase of zirconia and the decrease of noble alloys. Dental technicians did not report any significant change in working relationships and staffing as a result of CAD/CAM incorporation. High initial investment cost was the most common reason quoted from non-users, along with the lack of such technology in their working environment.

The use of patient-specific implants in orthognathic surgery: A series of 32 maxillary osteotomy patients.

The use of virtual surgery, patient-specific saw and drill guides, and custom-made osteosynthesis plates is rapidly spreading from deformity surgery to orthognathic surgery. Most of the commercially available systems are using computer-aided design/computer-aided manufacture (CAD/CAM) wafers to produce patient-specific saw guides. However, most plate systems provided are still the conventional "in stock" mini plates that can be individually designed by pre-bending according to the stereolithographic model of the patient. Custom made three-dimensional (3D) printed implants have earlier been demonstrated to be an ideal solution in deformity surgery and in reconstruction of complex posttraumatic cases. In this study, we report the novel use of patient-specific saw and drill guides combined with patient-specific 3D titanium alloy implants as a fixation system in maxillary movement after Le Fort I and bimaxillary osteotomies (n = 32). The implants were individually designed for each patient to follow anatomical structures and to provide exact positioning and stability of the repositioned maxilla.

Precision of Dental Implant Digitization Using Intraoral Scanners.

PURPOSE: The digitization of scanbodies on dental implants is required to use computer-aided design/computer-assisted manufacture processes for implant prosthetics. Little is known about the accuracy of scanbody digitization with intraoral scanners and dental lab scanners. This study aimed to examine the precision of different intraoral digital impression systems as well as a dental lab scanner using commercially available implant scanbodies. MATERIALS AND METHODS: Two study models with a different number and distribution of dental implant scanbodies were produced from conventional implant impressions. The study models were scanned using three different intraoral scanners (iTero, Cadent; Trios, 3Shape; and True Definition, 3M ESPE) and a dental lab scanner (D250, 3Shape). For each study model, 10 scans were performed per scanner to produce repeated measurements for the calculation of precision. The distance and angulation between the respective scanbodies were measured. The results of each scanning system were compared using analysis of variance, and post hoc Tukey test was conducted for a pairwise comparison of scanning devices. RESULTS: The precision values of the scanbodies varied according to the distance between the scanbodies and the scanning device. A distance of a single tooth space and a jaw-traversing distance between scanbodies produced significantly different results for distance and angle measurements between the scanning systems (P < .05). CONCLUSION: The precision of intraoral scanners and the dental lab scanner was significantly different. The precision of intraoral scanners decreased with an increasing distance between the scanbodies, whereas the precision of the dental lab scanner was independent of the distance between the scanbodies.

The Accuracy of Fit of Crowns Made From Wax Patterns Produced Conventionally (Hand Formed) and Via CAD/CAM Technology.

OBJECTIVE: The aim of this study was to compare the marginal and internal fit accuracy of crowns constructed using three different wax production methods; conventional, milled, and 3D printed and utilizing three different cement gap thicknesses. METHODS: 15 identical stone dies were made for each method. Wax patterns were produced and then cast into metal crowns, which were assessed for differences in accuracy of both marginal and internal fit. Measurement points were 4 points per crown; occlusal, axial, marginal gap, and marginal discrepancy points. A silicone impression technique and conventional cementation technique were employed to facilitate the measurements. RESULTS: There was no significant difference (p > 0.05) in accuracy between the digitally and manually produced crowns, with the 3D printed crowns being slightly more accurate. Whereas, statistically significant differences were noticed between the conventional versus printed groups, in occlusal and marginal gap points (p < 0.05). CONCLUSION: The marginal and internal fit of 3D printed wax patterns is more accurate than the other two production methods. The milling of wax crowns is as accurate as the conventional hand carved production in terms of internal and marginal fit. The manufacturer recommended offset/die-spacer of 30 µm produced the most accurate internal and marginal fits.

3D fitting accuracy evaluation of CAD/CAM copings - comparison with spacer design settings.

OBJECTIVES: The accuracy of computer-aided design/computer- aided manufacturing (CAD/CAM) systems is linked to their technical characteristics and reliability for manufacturing the restoration designed. The aim of this study was to compare the accuracy of fit of zirconia copings manufactured with different CAD/CAM systems and their capacity to conform to pre-established spacer design settings. METHODS: Sixty zirconia copings were manufactured by three CAD/CAM systems, with their spacers set as recommended by their manufacturer on occlusal, axial, and marginal surfaces. The 3D triple-scan optical technique was used to obtain a fit mapping and to analyze the marginal and axial accuracy of fit. The reliability of the 3D measurement method was estimated using intraclass correlation and repeatability coefficients. The preparation coping interface width results were statistically analyzed using non-parametric analysis (Kruskal-Wallis, one-way ANOVA, and Wilcoxon signedrank tests) (P < 0.05). RESULTS: The repeatability coefficient was 6, 8, and 15 µm for axial, marginal, and occlusal interface width measurements, respectively. For the three systems tested, no differences were found in the marginal area of the copings studied, with a mean fitting accuracy ranging from 54.3 to 66.6 µm interface width. Statistically significant differences between groups were observed for the fitting accuracy measured in axial and occlusal areas. With the spacers set in the different areas, mean fit measurements of the zirconia copings were significantly larger, with an increased fit width ranging from 30 to 73 µm. SIGNIFICANCE: The three CAD/CAM systems evaluated allowed similar marginal accuracy but failed to reproduce the pre-established spacer parameters, with larger spacing showing throughout.

Influência do agente cimentante e desajuste interno na adaptação marginal de coroas em resina nanocerâmica / Influence of the cement agent and internal mismatch in the marginal adaptation of nanoceramic resins crowns

A adaptação marginal é um dos requisitos fundamentais para a longevidade e o sucesso das restaurações. O objetivo desse estudo foi avaliar a influência do desajuste interno associado à diferentes agentes cimentantes na desadaptação marginal de coroas em resina nanocerâmica (Lava Ultimate 3M ESPE) confeccionadas pelo sistema CAD-CAM. A partir do escaneamento de um preparo de coroa total em um pré-molar, foram obtidos 36 modelos em metal. Esses foram divididos em seis grupos de acordo com o desajuste interno (70 µm ou 100 µm) e o cimento (Fosfato de zinco- SS White, Cimento de ionômero de vidro- Ketac Cem 3M/ESPE e Cimento resinoso- Relyx Ultimate 3M/ESPE). Após escaneamento de todos os modelos as coroas foram confeccionadas a partir da fresagem de blocos de resina nanocerâmica (Lava Ultimate 3M/ESPE). Com auxílio de microscópio óptico comparador (40X) foram medidas as desadaptações marginais prévia e posteriormente à cimentação, sendo considerados 8 pontos ao longo do término em todas as faces do corpo de prova. Os valores obtidos após serem submetidos aos testes two-way anova e teste t, demonstraram que as coroas confeccionadas com desajuste interno de 70 µm apresentam desadaptação marginal inferior estatisticamente significante às coroas com desajuste interno de 100 µm. Para o desajuste interno de 70 µm o grupo do cimento fosfato de zinco apresentou o menor gap marginal, sendo que este valor não foi estatisticamente diferente em relação ao grupo do Ketac Cem. Ainda com esse desajuste, o grupo do Ketac Cem não apresentou diferença estatística significante em relação ao grupo do Relyx Ultimate, no entanto esse último promoveu "gap" marginal estatisticamente maior em relação ao grupo do cimento fosfato de zinco. Para o desajuste interno de 100 µm não houve diferença estatisticamente significante no "gap" marginal entre os três cimentos avaliados. O presente estudo demonstrou através da metodologia utilizada, que a menor desadaptação marginal observada nas restaurações de Lava Ultimate, foi proveniente do desajuste interno de 70 µm. Neste grupo os cimentos de fosfato de zinco e de ionômero de vidro demonstraram melhor comportamento comparado ao cimento resinoso, embora o cimento de ionômero de vidro numericamente, mas não estatisticamente tenha apresentado resultado inferior ao do fosfato de zinco

The marginal adaptation is one of the basic requirements for the longevity and success of restorations. The aim of this study was to evaluate the influence of the internal imbalances associated with different luting agents on marginal leakage of crowns Nanoceramic resin ( Lava Ultimate 3M ESPE) made by CAD-CAM system. From the scanning of a full crown preparation in a pre molar were obtained 36 metal models. These were divided into six groups according to the internal imbalances ( 70 or 100 micrometres) and cement (SS White Zinc phosphate, glass ionomer cemet Ketac Cem 3M/ Espe and resinous cement Relyx Ultimate 3M / Espe). After scanning all models crowns were made from milling Nanoceramic resin blocks (Lava Ultimate 3M / Espe). With the aid of optical comparator microscope (40X) were measured prior marginal mismatches and after the cementation, being considered 8 points along the end in all specimen faces. The values were submitted to ANOVA two-way test and t test. Results showded that crowns made with internal imbalances of 70 uM show statistically significant lower marginal leakage to the crows with internal imbalances of 100 micrometres. For the internal imbalances 70 uM zinc phosphate cement group showed the lowest "gap" marginal, and this figure does not show a statistically significant difference compared to Ketac Cem gropu. Even with this misfit, Ketac Cem group showed no statistically significant difference in relation to Relyx Ultimate group, though the latter showed a statistically significant difference compared to zinc phosphate cement group. For the internal imbalances of 100 micrometres there was no statistically significant difference in the "gap" marginal among the three cements. This study demostrated through the methodology used, the lower marginal leakage oberved in Lava Ultimate restorations, was from the inner misfit 70 micrometers...

Uso do cad-cam no tratamento cirúrgico e protético de ameloblastoma mandibular: relato de caso / Cad-cam use in the surgical and prosthetic treatment of mandibular ameloblastoma: case report

A introdução da tecnologia CAD-CAM no dia-a-dia das especialidades Odontológicas, em particular da Cirurgia Bucomaxilofacial e da Prótese Dentária, abriram um novo horizonte de possibilidades terapêuticas para o tratamento de diversas patologias bucais que culminam com perda de estrutura óssea e edentulismo parcial. Este trabalho faz um relato de caso clínico, no qual um paciente acometido de ameloblastoma mandibular recebeu tratamento cirúrgico e protético auxiliado pelo CAD-CAM (AU)

The introduction of CAD-CAM technology in a daily basis into Dental specialities, particularly in Oral Surgery and Prosthodontics, has opened a new horizon of therapeutic possibilities for the treatment of many oral pathologies that lead to loss of bone structure and partial edentulism. This paper brings a case report of a patient with mandibular ameloblastoma which received surgical and prosthetic treatment with the use of CAD-CAM technology (AU)

Reliability and validity of intraoral and extraoral scanners.

BACKGROUND: This study evaluated the reliability and validity of one extraoral [Ortho Insight 3D™ (Motionview Software, Hixson, TN/USA)] and two intraoral [ITero™ (Align Technologies, San Jose, CA/USA) and Lythos™ (Ormco Corp., Orange, CA/USA)] scanners. METHODS: Fifteen dry human mandibles were scanned twice with each of the scanners, and digital models were generated. Five measurements were made on the dry mandibles and on each of the generated models, including intermolar width, intercanine width, posterior arch length, premolar crown diameter, and canine height. Systematic and random errors were evaluated based on replicate analyses. Differences were assessed using paired Student's t tests. RESULTS: Replicate analyses showed statistically significant systematic errors for only one measure (intermolar width measured from Ortho Insight 3D scans). Measurements taken from all three scanners were highly reliable, with intraclass correlations ranging from .926 to .999. Method errors were all less than 0.25 mm (averaged ≈ 0.12 mm). Posterior arch length and canine height were significantly smaller when measured on the Ortho Insight 3D scans than when measured on the dry mandibles and significantly smaller than when measured from the ITero and Lythos models. CONCLUSIONS: While all three scanners produced reliable measures, Ortho Insight 3D systematically underestimated arch length and canine height.