Effect of printing technology, layer height, and orientation on assessment of 3D-printed models.

BACKGROUND: Three-dimensional (3D) printing technologies have become popular in orthodontics. The aim of this study is to determine the effect of printing technology, orientation, and layer height on the accuracy of 3D-printed dental models. METHODS: The maxillary arch of a post-treatment patient was scanned and printed at different orientations (0°, 90°) and layer thicknesses (25 µm, 50 µm, 100 µm, and 175 µm) using two different printing technologies (digital light processing and stereolithography). The 120 models were digitally scanned, and their average deviation from the initial model was analyzed using 3D algorithm. A multivariable linear regression analysis was used to estimate the effect of all variables on the average deviation from the initial model for the common layer thicknesses (50/100 µm). Finally, one-way ANOVA and Tukey posthoc test was used to compare the stereolithography (SLA) 25 µm and digital light processing (DLP) 175 µm groups with the groups that showed the least average deviation in the former analysis. RESULTS: The multivariable linear regression analysis showed that the DLP 50 µm (mean ± SD: -0.022 ± 0.012 mm) and 100 µm (mean ± SD: -0.02 ± 0.009 mm) horizontally printed models showed the least average deviation from the initial model. Finally, the DLP 175 µm horizontally printed models (mean ± SD: 0.015 ± 0.005 mm) and the SLA 25 µm horizontally (mean ± SD: 0.011 ± 0.005 mm) printed models were more accurate. CONCLUSIONS: All the models showed dimensional accuracy within the reported clinically acceptable limits. The highest accuracy was observed with DLP printer, 175 µm layer thickness, and horizontal orientation followed by SLA printer, 25 µm layer thickness, and horizontal orientation.

The uses of 3-dimensional printing technology in orthodontic offices in North America.

INTRODUCTION: The purpose of this study was to examine the use of orthodontic 3-dimensional (3D) printing technology in North America and to understand why orthodontists are, or are not, incorporating 3D printing technology in their practices. METHODS: A survey questionnaire was delivered on a secure online platform, RedCap (Case Western Reserve University Clinical and Translational Science Award; no. UL1TR002548). The survey consisted of 14-34 items with branching logic. The association between participant demographics and in-house 3D printing was assessed using a chi-square test of independence. RESULTS: A total of 518 responses were recorded. The highest number of responses came from respondents in the 36-45-year age group. Most of the respondents were practice owners; 46.9% had 3D printers in their office. Chi-square tests of independence were performed on the data to see which associations existed. The strongest statistical associations with using an in-house 3D printer are seen with patient load, practice type, years since residency, and orthodontist's position. CONCLUSIONS: Approximately 75% of orthodontists use 3D printing technology in some capacity in North America. Major factors that influenced orthodontists to incorporate 3D printing technology into their office were self-interest and research. Major factors that have prevented orthodontists from not incorporating 3D printing technology into their office were space for equipment/ventilation and digital workflow training deficit. Orthodontists use their 3D printers mostly to make plastic retainers from printed models. The strongest associations with using in-house 3D printers are seen in patient load, practice type, years since residency, and orthodontist position. Increasing patient load and being in private practice increases the likelihood of having a 3D printer.

Comparing virtual setup software programs for clear aligner treatment.

BACKGROUND: The aim of this study was to compare the outcomes of the same amount of tooth movement among four different virtual setup software programs. METHODS: This retrospective study included 32 patients who underwent Invisalign treatment. Patients' initial stereolithography (STL) files were imported to three different software programs (SureSmile Aligner [Dentsply Sirona, Charlotte, NC], Ortho Insight 3D [Motion View software, Chattanooga, TN], and Ortho Analyzer [3Shape, Copenhagen, Denmark]). After virtually moving teeth based on the numbers from ClinCheck Pro (Align Technology, Inc., Santa Clara, CA) tooth movement tables, final STL files were exported from all four software programs. ClinCheck Pro final STL files were used as references, while final STL files from the other software programs were used as targets. Superimpositions were performed between references and target STL files using Geomagic Control X software (3D Systems, Rock Hill, SC), and color-coded maps were obtained to illustrate potential differences. RESULTS: Intraclass correlation coefficient showed a high degree of reliability for repeated methodology (0.995-0.997). The differences among absolute averages (Abs Avg.), averages of positive values (+Avg.), and negative values (-Avg.) for both upper and lower models were significant among all software programs (ClinCheck Pro, SureSmile Aligner, Ortho Insight 3D, and Ortho Analyzer), for both upper and lower STL files, the smallest difference was found between ClinCheck Pro and SureSmile Aligner with a median of (0.03, 0.31, -0.19) mm for upper and (0.02, 0.29, -0.17) mm for lower STL files (Abs Avg., +Avg. and -Avg.), respectively. The biggest difference was found to be between ClinCheck Pro and Ortho Analyzer with a median of (0.05, 0.46, -0.45) mm for upper and (0.06, 0.48, -0.40) mm for lower STL files. There were no significant differences in the number of aligners per patient. CONCLUSIONS: Final outcomes of the same amount of tooth movement in four different software programs differed significantly. The number of aligners per patient remained unchanged.

Craniofacial Orthodontic Experience in CODA-Accredited Orthodontic Residency Programs.

To evaluate orthodontic care for patients with craniofacial anomalies (CFA) by identifying orthodontic residents' preparedness to treat certain conditions and willingness to receive more training in CFA.A 12-question survey was sent through the American Association of Orthodontics (AAO) organization to orthodontic residents. Questions were primarily designed to obtain information on the frequency with which they dealt with patients with CFA in their training, specific craniofacial conditions that orthodontic residents feel comfortable treating.A total of 150 participants out of 1066 responded. Of the 150 responses, 35% were first-year residents, 43% second year, and 22% were third-year residents. Thirty nine percent of residents saw 3 or more CFA patients during their residency followed by 24% that saw no patients with CFA. Forty five percent reported that 1 to 3 hours of lecture time was devoted to CFA per month. Sixty percent felt their training in CFA was not sufficient to feel comfortable treating these patients in practice. Specifically, 62% felt comfortable treating Down syndrome, 84% unilateral cleft lip and/or palate, and 64% bilateral cleft lip and/or palate, while the majority did not feel comfortable treating Pierre Robin sequence (68%), Cleidocranial dysplasia (65%), Crouzon syndrome (75%), Pfeiffer syndrome (80%), Treacher Collins syndrome (76%), Apert syndrome (76%), CHARGE syndrome (84%), and DiGeorge sequence (84%). Seventy eight percent of residents reported that they would like more training in treating craniofacial.Orthodontic residents did not feel comfortable treating patients with CFA. Majority of the residents felt that they would like to learn more about CFA.

Cone-beam computed tomography assessment of maxillary anterior alveolar bone remodelling in extraction and non-extraction orthodontic cases using stable extra-alveolar reference.

OBJECTIVE: To explore alveolar cortical positional change in response to tooth movement in extraction and non-extraction orthodontic cases, using cone-beam computed tomography (CBCT) and stable extra-alveolar references. MATERIALS AND METHODS: The pre-treatment (T1) and post-treatment (T2) CBCT scans of 25 extraction (EXT) and matched 25 non-extraction (Non-EXT) orthodontic cases were imported into Dolphin Imaging 3D, and oriented uniformly. Sagittal and axial CBCT cross-sections were traced using customized software-generated guides. The displacement of teeth and alveolar bone cortices were automatically measured using the palatal plane (PP) and the line perpendicular to PP and passing Sella as reference. Intra- and inter-group differences between T1 and T2 were analysed. Subjects were also superimposed three-dimensionally using Geomagic Control X for qualitative analysis of cortical remodelling. RESULTS: The EXT group showed incisor retraction, while the Non-EXT group exhibited statistically significant incisor anterior tipping (P < .05). In EXT, both the labial and palatal cortices are resorbed. Non-EXT showed labial cortex anterior modelling, and statistically significant palatal cortex resorption (P < .05). In both groups, statistically significant decrease in total and palatal alveolar widths, increase in labial widths, and palatal dehiscence were observed. Comparatively, EXT showed significantly more incisal total and palatal width decrease and palatal vertical bone loss. CONCLUSION: Labial cortical remodelling was shown to follow anterior tooth movement, but the palatal cortical response to incisor retraction and labial cortical remodelling in general remained inconclusive. Narrowing of the alveolar housing and palatal dehiscence were observed regardless of extraction following orthodontic treatment.

Comparing a Fully Automated Cephalometric Tracing Method to a Manual Tracing Method for Orthodontic Diagnosis.

Background: This study aims to compare an automated cephalometric analysis based on the latest deep learning method of automatically identifying cephalometric landmarks with a manual tracing method using broadly accepted cephalometric software. Methods: A total of 100 cephalometric X-rays taken using a CS8100SC cephalostat were collected from a private practice. The X-rays were taken in maximum image size (18 × 24 cm lateral image). All cephalometric X-rays were first manually traced using the Dolphin 3D Imaging program version 11.0 and then automatically, using the Artificial Intelligence CS imaging V8 software. The American Board of Orthodontics analysis and the European Board of Orthodontics analysis were used for the cephalometric measurements. This resulted in the identification of 16 cephalometric landmarks, used for 16 angular and 2 linear measurements. Results: All measurements showed great reproducibility with high intra-class reliability (>0.97). The two methods showed great agreement, with an ICC range of 0.70−0.92. Mean values of SNA, SNB, ANB, SN-MP, U1-SN, L1-NB, SNPg, ANPg, SN/ANS-PNS, SN/GoGn, U1/ANS-PNS, L1-APg, U1-NA, and L1-GoGn landmarks had no significant differences between the two methods (p > 0.0027), while the mean values of FMA, L1-MP, ANS-PNS/GoGn, and U1-L1 were statistically significantly different (p < 0.0027). Conclusions: The automatic cephalometric tracing method using CS imaging V8 software is reliable and accurate for all cephalometric measurements.

Comparing 3D Tooth Movement When Implementing the Same Virtual Setup on Different Software Packages.

BACKGROUND/OBJECTIVES: The purpose of this study was to compare the differences in tooth movements when implementing the same virtual setup on the following four different software packages: ClinCheck® Pro, Ortho Analyzer®, SureSmile®, and Ortho Insight 3D®. MATERIALS/METHODS: Twenty-five adult patients treated with Invisalign® at the Case School of Dental Medicine (CWRU)'s department of orthodontics were retrospectively collected. Initial stereolithography (STL) files were obtained and imported into three software packages. The teeth were moved in order to replicate the virtual setup from ClinCheck® Pro. The final outcomes were exported from each software package. ClinCheck® Pro STL files were used as the reference while STL files produced by the other software packages were used as the targets. Best fit superimpositions were performed using Geomagic® Control X. Based on the results, tooth position was adjusted in the three software packages until the virtual setups from ClinCheck® Pro were replicated. Once confirmed, the tables containing the tooth movements were compared. The number of aligners and number of attachments automatically generated from each of the software packages were also evaluated. RESULTS: Extrusion/intrusion (p ≤ 0.0001) and translation buccal/lingual (p ≤ 0.0004) were significantly different among the software packages. ClinCheck® Pro and SureSmile® (p ≤ 0.000), SureSmile® and Ortho Insight 3D® (p ≤ 0.014), SureSmile® and Ortho Analyzer® (p ≤ 0.009), and Ortho Insight 3D® and Ortho Analyzer® (p ≤ 0.000) generated a significantly different number of maxillary aligners. The results varied slightly for mandibular aligners, with only ClinCheck® Pro and Ortho Insight 3D® (p ≤ 0.000), SureSmile® and Ortho Insight 3D® (p ≤ 0.000), and Ortho Insight 3D® and Ortho Analyzer® (p ≤ 0.000) exhibiting a significant difference. ClinCheck® Pro and SureSmile® (p ≤ 0.000) differed significantly in the number of attachments produced. CONCLUSIONS: There are statistically significant differences in extrusion/intrusion, translation buccal/lingual, the number of aligners, and the number of attachments when implementing the same virtual setup on different software packages. Clinicians may need to consider this when utilizing software programs for digital diagnosis and treatment planning.

Comparing different software packages for measuring the oropharynx and minimum cross-sectional area.

INTRODUCTION: Several imaging software packages report the ability to measure the oropharynx and minimum cross-sectional area (MCA). This study aimed to compare 4 imaging software packages for measuring the oropharynx volume and MCA. METHODS: Twenty-eight randomly selected cone-beam computed tomography scans had oropharynx volume and MCA calculated by 2 experienced operators using 4 different programs: Dolphin 3D (version 11.95.8.64; Dolphin Imaging & Management Solutions and Management Solutions, Chatsworth, Calif), InVivo Dental (version 6; Anatomage Inc, San Jose, Calif), OnDemand3D (version 1.0.10.7510; CyberMed, Seoul, South Korea), and ITK-SNAP (version 3.8.0; www.itksnap.org). The measurements were repeated after 2 weeks, and intraclass correlation coefficients were used for the reliability tests. Analysis of variance with the Tukey post-hoc test was used to compare the measurements of oropharynx and MCA with different software programs. Paired t tests were used to compare measurements of both investigators and software programs. Bland-Altman analysis was used to assess interexaminer reliability and agreement between the software programs. RESULTS: The intraclass correlation coefficients revealed excellent repeatability for the 4 programs for both investigators. Analysis of variance showed no statistically significant difference between programs when comparing the oropharynx and MCA. There were no significant differences in software programs when measuring the airway. Bland-Altman showed the maximum difference as 4.1 cm3 for volume and 35 mm2 for MCA. Those differences were below the standard deviations of 5.33 cm3 for volume and 73.75 mm2 for MCA. CONCLUSIONS: The use of 4 different software packages to measure the airway for oropharynx volume and MCA showed high intraoperator and interoperator reliability, no statistically significant difference when using analysis of variance, Tukey post-hoc, paired t tests, and variations within one standard deviation when using Bland-Altman.

Pharyngeal airway dimensional changes after orthodontic treatment with premolar extractions: A systematic review with meta-analysis.

INTRODUCTION: The objective of this research was to evaluate the effect of orthodontic extraction on the pharyngeal airway volume and Minimum cross-sectional area (MCA) in growing and adult patients. METHODS: Seven databases, unpublished gray literature, and the references list of the identified articles were electronically searched for relevant studies that met our eligibility criteria. Included studies assessed the effect of dental extraction or sagittal dental movements on pharyngeal airway dimensions. The quality of the included studies was assessed using the methodological index for nonrandomized studies. In addition, a meta-analysis was conducted using the RevMan 5 (Nordic Cochrane Centre, Cochrane Collaboration, Copenhagen, Denmark). RESULTS: In 7 studies, 268 treated patients with a mean age of 19.1 ± 7.6 years and 342 nonextraction control group subjects with a mean age of 19.3 ± 7.2 years were included. Compared with the control group, no statistically significant difference was found in total, nasopharyngeal, glossopharyngeal, oropharyngeal volume, or MCA (P >0.05) in the extraction group except in oropharyngeal volume in which a statistically significant increase in the volume 0.41 cm3 (95% CI, 0.05-0.80; P = 0.03) was detected. The clinical significance of this increase is questionable. Included studies showed a moderate to high risk of bias. CONCLUSIONS: There is no strong evidence to support the concept that premolar extractions in bimaxillary protrusion or crowded growing and adult patients reduce either pharyngeal airway volume or MCA. Moreover, as the level of evidence was considered very low for all variables, the magnitude, and direction of the summaries have to be interpreted with caution. Future studies with better quality could significantly affect the direction and strength of the results. TRIAL REGISTRATION NUMBER: PROSPERO CRD42018089924.

Ten years of miniscrew use in a U.S. orthodontic residency program.

INTRODUCTION: Orthodontic miniscrews have become popular not only because they can provide an absolute form of anchorage, but also because they can reduce the required patient compliance when compared with traditional orthodontic anchorage. The objective of this study was to examine success rates of miniscrews placed by orthodontic residents and to evaluate which factors may affect insertion outcomes. METHODS: The sample consisted of 109 consecutive miniscrews placed in 60 patients (27 males and 33 females). Miniscrews were placed at 4 different insertion sites (anterior palate [n = 31], palatal alveolar process [n = 25], maxillary buccal alveolar process [n = 15], and mandibular buccal alveolar process [n = 38]). Analysis of variance tests were used to evaluate the influence of insertion sites and anchorage type (direct vs indirect) on the success rate. RESULTS: The overall success rate for miniscrews was 72.5%. The success rate was 83.9% in the anterior palate, 76% in the palatal alveolar process, 60% in the maxillary buccal alveolar process, and 65.8% in the mandibular buccal alveolar process. The success rate was significantly higher in indirect anchorage (84.2%) compared with direct anchorage (58.8%). CONCLUSIONS: Palatal miniscrews were more successful than buccal miniscrews. Indirect anchorage mechanics had a higher success rate than direct anchorage mechanics.

Accuracy of Three-Dimensional Upper Airway Prediction in Orthognathic Patients Using Dolphin Three-Dimensional Software.

BACKGROUND: Orthodontists and surgeons have been looking for more accurate methods to predict surgical outcomes in patients with skeletal discrepancies. METHODS: The sample consisted of 20 patients from the surgical clinic of a graduate orthodontic program who had been treated with Le Fort I maxillary movement, bilateral sagittal split osteotomy, with or without genioplasty. All patients had to have preoperative (T0) and at least 6 months postoperative (T1) cone-beam computed tomographies that were imported to Dolphin 3-dimensional (3D) software. The 3D voxel-based superimposition on the cranial base was performed for T0 and T1 to accurately measure the skeletal surgical movements. A virtual orthognathic surgery was performed on T0 to mimic the actual skeletal osteotomies using the treatment simulation tool in Dolphin 3D. A prediction 3D soft-tissue image (Tp) was generated based on the Dolphin virtual skeletal planning. The upper airway was segmented and exported as stereolithography surface files in both T1 and Tp. The measurements of the 3D volume of the airway were calculated and compared among T1 and Tp by using surface superimposition technique. Mean and standard deviations of upper airway volume were compared and correlated using paired t-test. RESULTS: There was no statistically significant difference between the upper airway volume of T1 and Tp. CONCLUSION: Dolphin 3D delivers accurate airway prediction which is an important step in 3D virtual planning.

Comparison of the Pharyngeal Airway Volume Between Patients With Ectodermal Dysplasia and Unaffected Controls: A Cone-Beam Computed Tomography Study.

PURPOSE: Ectodermal dysplasias (EDs) are a diverse set of hereditary conditions in which 2 or more ectodermal structures develop abnormally. The purpose of this study was to use cone-beam computed tomography (CBCT) scans to measure the pharyngeal airway volume and minimum cross-sectional area (MC) among patients with ED and compare them with healthy controls. PATIENTS AND METHODS: The pretreatment CBCT scans of 9 individuals with ED and 61 controls were analyzed. Lateral cephalograms were created from the CBCT volumes and then traced and compared between the 2 groups. Airway volumes were evaluated by Dolphin 3D software (Dolphin Imaging, Chatsworth, CA) to compare the total pharyngeal volume, nasopharyngeal volume, oropharyngeal volume, hypopharyngeal volume, and MC. The mean airway volumes of the 2 groups were compared, and the odds ratio and relative risk of having an MC of less than 100 mm2 in the ED group were calculated. RESULTS: Intraclass correlation analysis showed excellent inter-rater reliability. All cephalometric features of controls were within the norms of patients with ideal skeletal-dental relationships. Patients with ED displayed significantly lower values for SNA (angle between sella-nasion and nasion-A point) (P = .018), ANB (angle between nasion-A point and nasion-B point) (P = .002), L1-MP (angle between long axis of mandibular incisor and gonion-menton plane) (P = .013), and L1-NB (distance between mandibular incisor and perpendicular line between nasion and B point) (P < .001). Although the ED group exhibited slightly smaller airway volumes for all subregions, the differences were not statistically significant for total pharyngeal volume, nasopharyngeal volume, oropharyngeal volume, hypopharyngeal volume, or MC (P > .05). The odds of having an MC of less than 100 mm2 were almost 3 times greater among ED patients, and the relative risk of an MC of less than 100 mm2 among ED patients was double that of controls. CONCLUSIONS: Although the craniofacial structures of individuals with ED are characterized by maxillary and midface deficiency, the airway volumes among affected individuals may not be significantly different from those of unaffected controls. However, patients with ED displayed a higher risk of having an MC of less than 100 mm2, which may be of clinical significance and warrants further investigations with larger samples.

Accuracy of Three-Dimensional Soft Tissue Prediction in Orthognathic Cases Using Dolphin Three-Dimensional Software.

INTRODUCTION: Orthodontists and surgeons have been looking for more accurate methods to plan and predict surgical outcomes in patients with skeletal discrepancies. METHODS: The sample consisted of 20 subjects from the surgical clinic of a graduate orthodontic program who had been treated with Le Fort I maxillary movement, bisagittal split osteotomy, with or without genioplasty. All subjects had to have preoperative (T0) and at least 6 months postoperative (T1) cone-beam computed tomographies that were imported to Dolphin three-dimensional (3D) software version 11.9 in digital imaging and communications in medicine format. Three-dimensional voxel-based superimposition on the cranial base was performed for T0 and T1 to accurately measure the skeletal surgical movements. A virtual orthognathic surgery was performed on T0 to mimic the actual skeletal osteotomies using the treatment simulation tool in Dolphin 3D. A prediction 3D soft tissue image (Tp) was generated based on the Dolphin virtual skeletal planning. The differences between Tp and T1 for all patients were measured using linear and angular measurements visualized by surface mapping. RESULTS: Significant differences were found between Tp and T1 in Nasolabial angle, Soft tissue A point, and Subalar area. CONCLUSIONS: The soft tissue prediction accuracy after double jaw surgery using Dolphin 3D is limited in some areas, especially upper lip and base of the nose.

Anatomic assessment of the mandibular buccal shelf for miniscrew insertion in white patients.

INTRODUCTION: Cortical bone thickness, bone width, insertion depth, and proximity to nerves are important factors when planning and placing orthodontic miniscrews. The objective of this study was to anatomically assess the mandibular buccal shelf in a white patient population as the insertion site for orthodontic miniscrews by investigating these 4 variables. METHODS: Measurements were made on cone-beam computed tomography scans of 30 white patients (18 girls, 12 boys; mean age, 14.5 ± 2 years). All measurements were taken adjacent to the distobuccal cusp of the first molar, and the mesiobuccal and distobuccal cusps of the second molar. Additionally, bone depth was measured at 2 height levels, 4 and 8 mm from the cementoenamel junction. Stereolithographic models of patients were superimposed on the cone-beam computed tomography volumes to virtually create an outline of the soft tissue on the cone-beam computed tomography image to allow identification of the purchase point height (mucogingival junction). The inferior alveolar nerve was digitally traced. Miniscrews (1.6 × 10 mm) were virtually placed at the buccal shelf, and their insertion depths and relationships to the nerve were assessed. Analysis of variance with post hoc analysis was used for data analysis. RESULTS: Insertion sites and measurement levels had significant impacts on both cortical bone thickness and bone width. Cortical bone thickness was typically greatest at the distobuccal cusp of the second molar. Bone width was also greatest at the distobuccal cusp of the second molar 8 mm from the cementoenamel junction. The greatest insertion depth was found again at the distobuccal cusp to the second molar, whereas the miniscrews had the greatest proximity to the nerve at this site also. CONCLUSIONS: The distobuccal cusp level of the mandibular second molar is the most appropriate site for miniscrew insertion at the buccal shelf in white patients.

Reliability of linear and angular dental measurements with the OrthoMechanics Sequential Analyzer.

INTRODUCTION: The aim of this study was to evaluate the reliability of newly developed software in the assessment of orthodontic tooth movement 3 dimensionally. METHODS: The sample consisted of pretreatment and posttreatment computed tomography scans and plaster dental models of 20 orthodontic patients treated with a hyrax palatal expander as a part of their comprehensive orthodontic treatment. Dental-arch measurements, including arch widths, tooth inclinations, and angulation parameters, were measured on the scans using InvivoDental 3D imaging software (version 5.1; Motionview, Hixson, Tenn). The plaster dental models were laser scanned and superimposed, and measurements were obtained digitally using the new software. Agreement between the digital models and the computed tomography measurements was evaluated with intraclass correlation coefficients, paired t tests, and Bland-Altman plots. A P value of ≤0.05 was considered statistically significant. RESULTS: High agreement, a nonsignificant paired t test, and no indication of agreement discrepancies were observed for most of the measured parameters. CONCLUSIONS: The results confirmed that the new software program offers a reliable tool for dental-arch measurements obtained from 3-dimensional laser-scanned models.