Digital Cast Research Articles

Establishing a CAD-CAM workflow for stabilization appliances (Michigan splints).

Stabilization appliances (Michigan splints) are considered well-studied and widely adopted for managing bruxism and temporomandibular disorders (TMDs). Traditionally, these appliances have been fabricated by wax modeling and pressing resin onto casts made from irreversible hydrocolloid or silicone impressions. This article provides a detailed description of an all-digital workflow that uses intraoral scanning and computer-aided design (CAD) software to design a stabilization splint on a digital cast that can be manufactured autonomously by a computer-aided manufacturing (CAM) grinding machine in a subtractive procedure. The workflow is applicable to both dentists and technicians. Special attention is given to aspects and procedures that are important for the successful fabrication of the splint. Working without a cast can save time and money, and the use of CAD-CAM technology provides a homogeneous splint material quality.

Three-dimensional assessment on digital cast of spontaneous upper first molar distorotation after Ni-ti leaf springs expander and rapid maxillary expander: A two-centre randomized controlled trial.

The aim of this randomized controlled trial (RCT) was to evaluate the spontaneous distorotation of upper first permanent molars and the transverse dentoalveolar changes on digital casts in growing patients following maxillary expansion treatment using either the Leaf Expander® or the rapid maxillary expander (RME), both anchored to the deciduous second molar. This study was a two-arm, parallel-assignment, RCT with a dual-centre design conducted at two teaching hospitals in Italy. Inclusion criteria included maxillary transverse deficiency, prepubertal development stage (cervical vertebra maturation stage [CVMS] 1-2) and early mixed dentition with fully erupted upper first permanent molars. Exclusion criteria were systemic diseases or syndromes, CVMS 3-6, agenesis of upper second premolars, unavailability of the second deciduous molar for anchorage and Class III malocclusion. Patients were randomly assigned to the Leaf Expander® or RME group using a computer-generated randomization list created by a central randomization centre. Randomization was conducted immediately before the start of treatment. The intervention involved treatment with either the Leaf Expander® or the RME. Both devices were anchored to the second deciduous molars. Following randomization, patients were further categorized based on the presence of no crossbite, unilateral crossbite or bilateral crossbite. The primary outcome measure was the distorotation of the upper first molar (U6). Secondary outcomes included measurements of interdental linear dimensions, specifically upper inter-canine width (53-63), upper inter-molar width (MV16-MV26) and upper inter-deciduous second molar width (55-65). The examiner analysing the digital casts was blinded to the treatment groups to prevent detection bias and ensure objective assessment. However, due to the nature of the intervention, blinding was not feasible for the patients and clinicians involved in administering the treatment. A total of 150 patients were enrolled and randomly assigned to two groups: 75 to the Leaf Expander® group and 75 to the RME group. Recruitment started in November 2021 and was completed in November 2022. At the time of analysis, the trial was complete with no ongoing follow-ups. ANOVA tests revealed no significant differences between the three subgroups (no-cross, unilateral-cross and bilateral-cross) within both the Leaf Expander® and RME groups at T0. The Leaf Expander® demonstrated significantly greater distorotation in the unilateral crossbite subgroup compared to the RME (p = .014). In terms of total molar distorotation, the Leaf Expander® appliance showed a significantly greater effect (12.66°) compared with conventional RME (7.83°). Linear regression analysis demonstrated a significant correlation between the extent of expansion and the degree of molar rotation. Maxillary expansion resulted in significant spontaneous molar distorotation when the appliance was bonded to the second deciduous molars. The Leaf Expander® exhibited significantly greater molar distorotation compared with conventional RME. The degree of molar distorotation was correlated with the extent of expansion obtained on the second deciduous molar. The trial was registered at ClinicalTrials.gov (ID: NCT05135962).

In vitro comparison of guide planes for removable partial dentures prepared with CAD-CAM-assisted templates, guiding rod templates, and freehand

ObjectivesThis study aimed to evaluate the accuracy of computer-aided design and computer-aided manufacturing (CAD-CAM)-assisted templates (CCAT), guiding rod templates (GRT), and freehand (FH) preparation of guide planes. MethodsForty-five identical maxillary resin casts were divided into three groups, in which the guide planes of the two abutment teeth were prepared using a CCAT (n=15), GRT (n=15), and FH (n=15). The CCAT and GRT were digitally designed on a digital cast of virtually prepared guide planes and fabricated using three-dimensional printing (3DP) technology. To assess the 3D trueness, the prepared guide planes were digitally scanned and compared to the virtually designed guide planes. The angle deviation was measured to assess the trueness of the direction of the guide plane preparation. Shapiro–Wilk and Levene's tests were used to check the normality and equivalence of the variance of the data. The data were compared by using the Kruskal‒Wallis H test (α=0.05). ResultsThe CCAT group exhibited significantly better 3D trueness (78.5±19.8 μm) than the GRT group (211.3±42.4 μm, p<0.05) and the FH group (198.9±44.3 μm, p<0.05). Additionally, the CCAT group (1.31±0.50°) showed significantly smaller direction trueness compared to the GRT (4.65±0.72°, p<0.05) and FH (5.64±0.70°, p<0.05) groups. ConclusionsThe novel CAD-CAM-assisted template significantly improved the quality of the guide planes compared with the GRT and FH procedures. This enhancement suggests that removable partial dentures can be predictably inserted immediately after guide plane preparation. Clinical SignificanceCAD-CAM-assisted templates improve the quality of guide plane preparation.

Validity of digital analysis versus manual analysis on orthodontic casts

As artificial intelligence within digital processes continues to advance and replace conventional manual workflows, it is crucial that digital data are consistent with analog data. The aim was to evaluate the validity and time efficiency of digital cast analysis on digital models in comparison with the manual, gold standard, cast analysis on plaster models. Cast analysis was performed on 30 patients in three various methods: manually measured variables on plaster models (MP), manually measured variables on digital three-dimensional models (MD), and automatically measured variables on digital three-dimensional models (AD) on digital models. Digital cast analysis was performed in CS Model+. Analyses included metrical and categorical variables and the required work time. Measurements in MD and AD were validated to MP. Validity of the metrical variables was analyzed with Bland-Altman, Dahlberg's formula, and paired sample t test. Categorical variables were validated by Cohen's Kappa. Work time was analyzed with Wilcoxon signed-rank test. Metrical variables had measurement errors ranging 0.4 to 1.4 mm between MP-MD, and 0.6 to 3.2 mm between MP-AD. Observations of categorical variables had a moderate to strong (0.65 to 0.9) level of agreement between MP-MD, and a weak to moderate (0.4 to 0.68) level of agreement between MP-AD. Data for dental stage, vertical, and transversal relation was not provided in AD. Cast analysis was performed quicker digitally, P ≤ 0.05. Digital cast analysis is consistent with manual cast analysis for metrical variables. Analyses of categorical variables show a weak level of agreement with automatic digital analysis, such as space conditions and midline assessments. Digital cast analysis optimizes time compared with manual cast analysis, with automatic analysis being the fastest.

Craniofacial Morphology and Knowledge of the Stability in Class III Malocclusion Growing Subjects

Introduction: to investigate the palatal and craniofacial relationship in Class III growing patients between successful and failed treated groups. Methods: Thirty-one patients treated with RME/FM/BB were enrolled (inclusion criteria: Caucasian ancestry, III Class malocclusion, maturation stage CS1-CS2, mixed dentition). Digital cast and cephalometric analysis were performed on pre-treatment and post-treatment records. Statistical analysis and a discriminant analysis was performed. GMM was used on digital dental casts with Procrustes analysis to assess the covariation between palatal and craniofacial morphology. Two groups (relapse, R, 19 and success S, 12) were identified. Results: R group showed a greater maxillary-anterior transversal width at T0. At T1 R showed a shorter maxillary-anterior length than S. A larger maxillary-anterior and posterior-transversal widths was found in both groups. S had greater maxillary-anterior and posterior-sagittal length. A larger mandibular-anterior and posterior-transversal widths was shown in R, while S showed no differences in mandibula. Maxillary-anterior and maxillary-posterior length were two predictive variables found by discriminant analysis. The PC1 showed significant changes in the palatal morphology and revealed differences for the craniofacial vertical components. Palatal and craniofacial shapes showed a significant covariation, linking the palatal width to skeletal divergence. Discussion: In Class III malocclusion increases in vertical divergence are correlated with a higher palatal vault and narrower width. A wider and shorter maxillary morphology could be a relapse factor for Class III orthopedic treatment, while the lack of mandibular modification could be predisposing for treatment success.

Influence of base designs on the manufacturing accuracy of vat-polymerized diagnostic casts using two different technologies

Statement of problemDiagnostic casts can incorporate different base designs and be manufactured using different vat-polymerization technologies. However, the influence of the interrelation between the base design and the 3D printing technology on the casts' final accuracy remains unclear. PurposeThe purpose of this in vitro study was to assess the influence of different base designs of 3D printed casts on the accuracy of 2 vat-polymerization technologies. Material and methodsA digital maxillary cast was obtained and used to generate 3 different base designs: solid (S group), honeycombed (HC group), and hollow (H group). The HC and H groups were subdivided based on the wall thickness of the cast design, resulting in 2 subgroups with thicknesses of 1 mm (HC1 and H1) and 2 mm (HC2 and H2) (N=100, n=10). Eleven reference cubes were added to each specimen for subsequent measurements. Specimens were manufactured by using 2 vat-polymerization 3D printers: Nextdent 5100 (ND group) and Sonic Mini 4K (SM4K group) and a resin material suitable for both 3D printers (Nextdent Model 2.0). A coordinate measuring machine quantified the linear and 3-dimensional discrepancies between the digital cast and each reference specimen. Trueness was defined as the average absolute dimensional discrepancy between the virtual cast and the specimens produced through additive manufacturing (AM), while precision was delineated as the standard deviation in dimensional discrepancies between the digital cast and the AM specimens. The data were analyzed using the Kruskal-Wallis and Mann-Whitney U pairwise comparison tests (α=.05). ResultsFor the NextDent group the trueness ranged from 21.83 µm to 28.35 µm, and the precision ranged from 17.82 µm to 37.70 µm. For the Phrozen group, the trueness ranged from 45.15 µm to 64.51 µm, and the precision ranged from 33.51 µm to 48.92 µm. The Kruskal-Wallis test showed significant differences on the x-, y-, and z-axes and in the 3D discrepancy (all P<.001). On the x-axis, the Mann-Whitney U test showed significant differences for the Phrozen group between the H-2 and H-1 groups (P=.001), H-2 and S groups (P<.001), and HC-2 and S groups (P=.012). On the y-axis, significant differences were found in the Phrozen group between the H-2 and H-1 groups (P=.001), the H-2 and S, H-1 and HC-1, and HC-1 and S groups (P<.001), the H-1 and HC-2 groups (P=.007), and the HC-2 and S groups (P=.009). The NextDent group exhibited significant differences, particularly among the HC-1 and H-2 groups (P=.004), H-1 (P=.020), and HC-2 (P=.001) groups; and on the z-axis significant differences were found in the Phrozen group between the H-2 and H-1 and S groups and the HC-2 group and H-1 and S groups (both P<.001). In the NextDent group, significant differences were found between the H-2 and HC-2 (P=.047) and HC-1 (P=.028) groups. For the 3D discrepancy analysis, significant differences were found in the Phrozen group between the H-2 and H-1 and S groups (P<.001), the H-1 and HC-2 groups (P=.001), the S and HC-1 and HC-2 groups (P<.001), and the H-1 and HC-1 groups (P=.002). In the NextDent group, significant differences were observed between the H-2 and HC-1 groups (P=.012). ConclusionsThe accuracy of digital casts depends on the manufacturing trinomial and base design of the casts. The honeycomb and hollow based designs provided the highest accuracy in the NextDent and Phrozen groups respectively for the material polymer tested. All specimens fell in the clinically acceptable range.

Effect of scan body designs and internal conical angles on the 3-dimensional accuracy of implant digital scans

Statement of problemAxial displacement is inevitable when connecting scan bodies to implants for digital scans using intraoral scanners, and axial displacement may reduce implant position accuracy in digital casts. However, studies assessing scan body type and accuracy are lacking. PurposeThe purpose of this in vitro study was to assess the linear and angular displacements of implants in digital casts using 2 scan body types with or without a vertical stop to minimize the axial displacement and 2 internal conical connection implants (ICCIs) with different internal conical angles. Material and methodsTwo identical reference casts were fabricated from epoxy resin by duplicating a partially edentulous mandibular dentiform. Each cast received 3 implants in the left first premolar, first molar, and second molar regions. One cast received an ICCI with a 7-degree internal conical angle (7-degree ICCI), and the other received an ICCI with an 11-degree internal conical angle (11-degree ICCI). A 10-mm polyetheretherketone (PEEK) cube was attached to the buccal area of the mandibular second premolar of each reference cast. A vertical stop was used in the experimental scan bodies to minimize the axial displacement, and conventional scan bodies were hand tightened to the implants in the reference casts. An intraoral scanner was used to fabricate 4 digital cast groups (2 implant types and 2 scan body types; each group had 10 casts). A coordinate measuring machine and digital inspection software program were used to measure the implant platform centroids (x, y, z) and projection angles (θXY, θYZ, θZX) of implant long axes in the reference and digital casts, respectively. One-way analysis of variance (ANOVA) and linear mixed model both with Tukey post hoc and 2-way ANOVA tests were performed to assess the significance of linear and angular displacements between groups (α=.05). ResultsSignificant differences were noted in all linear displacement variables among the 4 digital cast groups, except for Δx in the left first premolar implant. For the 7-degree ICCI, the linear displacement was statistically similar in the experimental and conventional scan bodies. However, for the 11-degree ICCIs, the experimental scan body group resulted in significantly smaller Δy, Δz, and Δd (Δd2=Δx2+Δy2+Δz2) than the conventional scan body group (P<.05). Overall, the 11-degree ICCIs demonstrated a significantly greater linear displacement than the 7-degree ICCI, regardless of the scan body type (P<.05). Significant differences between the test groups were observed for 10 of the 12 angular displacement variables (P<.05). ConclusionsThe 11-degree ICCIs demonstrated significantly greater linear displacements in Δy, Δz, and Δr than the 7-degree ICCIs. The experimental scan bodies with a vertical stop demonstrated significantly smaller linear displacements in the 11-degree ICCIs.

Accuracy of orthodontic movements with 3D printed aligners: A prospective observational pilot study.

Owing to the availability of 3D software, scanners, and printers, clinicians are encouraged to produce in-office aligners. Recently, a new directprinting resin (Tera Harz TC-85DAC) has been introduced. Studies on its mechanical characteristics and biological effects have been published; however, evidence on its efficacy in orthodontic treatment remains scarce. This pilot study aimed to investigate the accuracy of teeth movement achieved with directprinted aligners. Seventeen patients (eight males and nine females) with a mean age of 27.67 ± 8.95 years, presenting with dental rotations < 30° and spaces/crowding < 5 mm, were recruited for this study. The teeth movement was planned starting from a T0 digital dental cast. The 3D direct-printed aligners were produced using Tera Harz TC-85DAC resin. Once the orthodontic treatment was completed, a final digital cast was obtained (T1). The planned teeth positions were then superimposed onto the T0 and T1 digital models. The differences between the programmed movements and the achieved overall torque, tip, rotation, and transverse dimensions were assessed using the paired t test or Wilcoxon's signed rank test. The overall accuracies for torque, tip, and rotation were 67.6%, 64.2%, and 72.0%, respectively. The accuracy of the change in transverse diameter was 99.6%. Within the limits of the present pilot study (difficulties with abnormally shaped teeth and use of attachments), it can be concluded that 3D printed aligners can be successfully printed in-house and utilized for mildly crowded cases, with a comparable accuracy of tooth movement to that of other aligners.

A digital workflow for designing and manufacturing metal frameworks and removable partial dentures: A novel dental technique.

The purpose of this technical report is to demonstrate a fully digital workflow for designing and fabricating metal frameworks and removable partial dentures. After obtaining a digital cast of the dental arch with bilateral distal extension defect, computer-aided design software and 3D printing technology are used for the design and fabrication of the removable partial denture frameworks, denture teeth, and denture bases, instead of the traditional workflow. The assembly of the three components is facilitated through a meticulously structured framework. The technology, which prints metal frameworks, denture bases, and denture teeth through different processes with different materials, achieves full 3D printing technology for making removable partial dentures.

Trueness evaluation of three intraoral scanners for the recording of maximal intercuspal position.

This clinical study aimed to assess the trueness of three intraoral scanners for the recor-ding of the maximal intercuspal position (MIP) to provide a reference for clinical practice. Ten participants with good occlusal relationship and healthy temporomandibular joint were recruited. For the control group, facebow transferring procedures were performed, and bite registrations at the MIP were used to transfer maxillary and mandibular casts to a mechanical articulator, which were then scanned with a laboratory scanner to obtain digital cast data. For the experimental groups, three intraoral scanners (Trios 3, Carestream 3600, and Aoralscan 3) were used to obtain digital casts of the participants at the MIP following the scanning workflows endorsed by the corresponding manufacturers. Subsequently, measurement points were marked on the control group's digital casts at the central incisors, canines, and first molars, and corresponding distances between these points on the maxillary and mandibular casts were measured to calculate the sum of measured distances (DA). Distances between measurement points in the incisor (DI), canine (DC), and first molar (DM) regions were also calculated. The control group's maxillary and mandibular digital casts with the added measurement points were aligned with the experimental group's casts, and DA, DI, DC, and DM values of the aligned control casts were determined. Statistical analysis was performed on DA, DI, DC, and DM obtained from both the control and experimental groups to evaluate the trueness of the three intraoral scanners for the recording of MIP. In the control group, DA, DI, DC, and DM values were (39.58±6.40), (13.64±3.58), (14.91±2.85), and (11.03±1.56) mm. The Trios 3 group had values of (38.99±6.60), (13.42±3.66), (14.55±2.87), and (11.03±1.69) mm. The Carestream 3600 group showed values of (38.57±6.36), (13.56±3.68), (14.45±2.85), and (10.55±1.41) mm, while the Aoralscan 3 group had values of (38.16±5.69), (13.03±3.54), (14.23±2.59), and (10.90±1.54) mm. Analysis of variance revealed no statistically significant differences between the experimental and control groups for overall deviation DA (P=0.96), as well as local deviations DI (P=0.98), DC (P=0.96), and DM (P=0.89). With standardized scanning protocols, the three intraoral scanners demonstrated comparable trueness to traditional methods in recording MIP, fulfilling clinical requirements.

Comparative Analysis of Tooth Measurements on Conventional and Digital Study Model – Validity Reliability Study

Abstract Aim: The aim of the study was to assess the accuracy, consistency, and reproducibility of tooth measurements by comparing conventional dental cast models with their digital equivalents. Materials and Methods: The research sample consisted of 50 before-treatment, diagnostic, conventional cast models utilized for study and evaluation. Tooth measurements on the dental cast models were done using a digitized Vernier caliper (Precision, IP54). Three-dimensional (3D) model tooth measurements were obtained through scanning the conventional cast models using the Maestro 3D Dental Scanner (Italy). The comparison of validity and reliability between conventional and digital cast models was done through independent t-tests, Cronbach’s alpha test, and intraclass correlation coefficient (ICC). Results: The Independent t-test showed no statistically significant difference between conventional and digital cast models. Cronbach’s alpha test demonstrated high reliability between conventional and digital cast models, surpassing 0.9 in this study. Intraexaminer reliability (ICC) was nearly perfect agreement ranging from 0.82 to 0.99. Conclusion: The digital cast models exhibited user-friendly features and were shown to be a feasible substitute for conventional dental cast models, providing similar levels of accuracy and effectiveness. Consequently, the dental arch tooth measurements of digital cast models were equally accurate and consistent when compared to those obtained from conventional dental cast models.

Effect of splinting scan bodies on the trueness of complete arch digital implant scans with 5 different intraoral scanners

Statement of problemThe absence of fixed reference points can affect the trueness of complete arch intraoral digital implant scans. The effect of splinting intraoral scan bodies (ISBs) or the inclusion of artificial landmarks (AL) on the trueness of complete arch digital implant scans is still unclear. PurposeThe purpose of this study was to analyze the effect of splinting ISBs or the inclusion of AL on the trueness of complete arch digital implant scans with 5 intraoral scanners (IOSs). Material and methodsSix tissue-level dental implants (Straumann Tissue Level) were placed in an edentulous patient, and the correspondent definitive cast was digitized with a desktop scanner (IScan4D LS3i) to obtain the reference digital cast. Digital scans (n=10) were performed with 5 IOSs: TRIOS 4, Virtuo Vivo, Medit i700, iTero Element 5D, and Cerec Primescan. Three different scanning techniques were evaluated: conventional (cIOSs), splinted (sIOSs), and AL (AL-IOSs). The scan data obtained were imported into a metrology software program and superimposed to the reference digital cast by using a best-fit algorithm. The overall deviations of the positions of the ISBs were evaluated by using the root-mean-square (RMS) error (α=.05). ResultsThe mean ±standard deviation trueness values for the cIOSs, sIOSs, and AL-IOSs groups were 48 ±8 µm, 53 ±7 µm, and 49 ±11 µm, respectively, with no statistically significant differences (P=.06). Significant differences were found for the IOSs used with each technique (P<.001). Primescan (27 ±4 µm cIOSs; 28 ±3 µm sIOSs; 31 ±3 µm AL-IOSs) showed significantly higher trueness than iTero 5D (47 ±5 µm cIOSs; 47 ±4 µm sIOSs; 50 ±6 µm AL-IOSs) (P=.002) and TRIOS 4 (93 ±18 µm cIOSs; 76 ±18 µm sIOSs; 107 ±13 µm AL-IOSs) (P=.001) for all techniques. In addition, no significant differences were found between the techniques by using iTero 5D or Primescan (P=.348 and P=.059, respectively). ConclusionsThe cIOSs, sIOSs, and AL-IOSs techniques showed similar trueness. The IOS used influenced the trueness of complete arch digital implant scans.

Impact of internal design on the accuracy of 3-dimensionally printed casts fabricated by stereolithography and digital light processing technology

Statement of problemAltering the internal design of 3-dimensionally (3D) printed dental casts may help to reduce material and time consumption. However, it remains unclear whether such changes would compromise the accuracy of the casts. Further research is also needed to determine the optimal internal design that would maximize printing accuracy. PurposeThe purpose of this in vitro study was to evaluate the impact of internal design on the accuracy (trueness and precision) of 3D printed dental casts fabricated by stereolithography (SLA) and digital light processing (DLP) technology. Material and methodsA reference digital cast was obtained by scanning a maxillary typodont with an intraoral scanner to create 4 types of internal designs, including hollow interior with perforated base (HWB), hollow interior without base (HB), all solid (S), and internal support structure with perforated base (SWB). Digital casts with different internal designs were printed by two 3D printers with different technologies (SLA and DLP). The printed casts were scanned by a desktop scanner to obtain standard tessellation language (STL) format research digital casts. All reference and research digital casts were imported into a software program for comparison and analysis of accuracy. Differences between the reference and research digital casts were quantitatively indicated by the root mean square (RMS) value. The Kruskal-Wallis 1-way ANOVA was used to test significant differences between the different internal design types and the Mann-Whitney U test was used to test significant differences between the two 3D printers (α=.05). ResultsThe Kruskal-Wallis 1-way ANOVA revealed significant differences in the trueness and precision of different internal design types (all P<.001) for casts printed by both 3D printers. The trueness and precision were significantly worse for the HB design than for the other design types for casts printed by both 3D printers (all P<.05). Regardless of the design type, the trueness was significantly better for casts printed by the SLA-based printer than for casts printed by the DLP-based printer (all P<.05). The precision was significantly worse for casts printed by the SLA-based printer than for casts printed by the DLP-based printer (all P<.05). ConclusionsThe internal design may affect the accuracy of 3D printing. The base is necessary to ensure the accuracy of 3D printed dental casts, whereas the internal support structure did not affect the accuracy of 3D printed dental casts. An all-solid design led to higher precision, but not higher trueness. Dental casts printed with SLA technology have higher trueness and lower precision than those printed with DLP technology.

Anchorage Loss Evaluation during Maxillary Molars Distalization Performed by Clear Aligners: A Retrospective Study on 3D Digital Casts

The purpose of the research was to analyze the premolar and canine anchorage loss observed during maxillary molars distalization in subjects with Class II malocclusion treated with clear aligners. A total of 49 subjects (27 females, 22 males, mean age 14.9 ± 6 years) derived from the Department of Orthodontics of the University of Rome “Tor Vergata” were selected according to the following inclusion criteria: Caucasian ancestry, Class I or minor Class II skeletal malocclusion, Class II occlusal relationship, permanent dentition with fully erupted second molars, and good compliance with aligners. Each patient underwent the same non-extractive molar distalization protocol with no auxiliaries other than attachments and Class II elastics. Prior to treatment (T1) and at the end of the first maxillary molars distalization movement (T2), digital dental casts were taken by using an iTero intraoral scanner. Linear measurements were performed in order to evaluate the anchorage loss at the level of the second and first premolars and the canines. The statistical comparison of T2 and T1 values was obtained using a paired t-test (p &lt; 0.05). A statistically significant distalization of the maxillary first permanent molars (2.5 mm) was observed; a slight and not significant anchorage loss of the first and second premolars was assessed, while a statistically significant mesial movement of upper canines (1.33 mm) was highlighted. Clear aligner treatment was effective in obtaining a molar distalization movement. However, during molar distalization, an anchorage loss at the level of upper canines was observed.

Comparison of palatal volume and surface changes between bone-borne and tooth-tissue-borne maxillary expansion on cone beam computed tomography digital cast models.

To compare the changes of palatal volume and area in patients treated with tooth-tissue-borne palatal expanders (conventional Haas) and miniscrew-supported palatal expanders (modified Haas). The sample included casts of 22 patients treated as part of a clinical study at the Department of Orthodontics, Al-Azhar University, to correct their crossbite malocclusion. Patients were divided equally into two groups upon arrival. The first group, with a mean age of 12 years and 6 months, received the miniscrew-supported palatal expander. The second group, with a mean age of 12 years and 2 months, received the Haas design-palatal expansion appliance. Pre- and post-expansion dental casts were cone beam computed tomography scanned and the slices were constructed into 3D volumes. Fully automated superimposition was done for pre- and post-expansion 3D models. Palatal volume and area were determined, and all measurements were carried out blindly. Paired t-test was used to assess the mean differences within each group and Welch's t-test was applied to assess the mean changes between the two groups. Shapiro-Wilk test was used to test for the normality of the data. There were no statistical differences in volume changes either within each group or between the groups. Although area changes were statistically significant within each group, the difference between the groups was not significant. Changes that result from the use of either method to expand the upper arch occur primarily in the shape of the palate, but not in its size.

Difference in Incisal sum analysis in STL models and DICOM files of University of Cuenca students

A cross-sectional study was carried out among the students of the 7th cycle of the State University of Cuenca where the incisal sum of each student was analyzed by using STL models with the Nemocast program and by using tomographies with the Sidexis 4 program. It was possible to use a wide universe previously obtained from a database of 40 students, provided by the University of Cuenca, of which 19 were randomly chosen to be able to analyze the data without the aim of distorting and manipulating the data released. Through a meticulous evaluation of the analyzed data of the incisal sum of the 19 people, we proceeded to order the values ​​and standardize them, however, for a greater impact and veracity in the study, we proceeded to analyze the data and propose an alternative hypothesis: which would be corroborated through the "T Student" method. Finally, it was possible to find the values ​​of the mean and variance of each data grouping (format and incisal sum). Theoretical framework: To carry out this study, it is important to know that different orthodontic measurement parameters and different software used were used. These elements will be disclosed below. Mayoral analysis: This method can be used in permanent occlusion and allows estimation of the relative distances between the grooves that separate the buccal cusps from the lingual cusps of maxillary first and second premolars, and between the midline grooves where the mandibular cusps meet, the first molars of the maxilla. converge and normal patients should have dimensions of 35, 41, and 47 mm, respectively. When the value obtained is lower than the norm, a diagnosis of transverse micrognathism is obtained, and when a higher value is obtained, a diagnosis of transverse micrognathism is. [1] The disadvantage of this method is that the cross-sectional assessment is only performed in the maxilla and not in the mandible. [1] Nemoceph: NemoCast is an orthodontic software that allows you to perform digital cast analysis, digital diagnosis and planning, and export and print products.

A digital workflow to predict facial aesthetics in patients with maxillofacial trauma with implant retained prostheses.

Purpose To introduce a digital workflow for the prediction of facial aesthetics, especially in patients with dentation deformity caused by maxillofacial trauma.Methods Cone-beam computed tomography (CBCT) and three-dimensional facial scans of patients with radiographic prostheses were collected. The aforementioned data were uploaded to ProPlan CMF software and merged to generate a virtual patient with craniofacial hard tissue, realistic facial soft tissue, and remaining dentition. The radiographic prostheses were scanned to form a digital cast, which was fitted with its CBCT image to create the virtual prostheses. Postoperative facial soft tissue was simulated according to the movement of the virtual prostheses. An appropriate virtual diagnostic prosthesis plan was selected by the patient and dentist. Subsequently, prosthetically driven implant guide and restoration were designed and fabricated.Conclusions A virtual patient was successfully constructed. A 4-mm protrusion of the virtual prosthesis was chosen. Subsequently, implant surgery was performed, and dental prostheses were fabricated based on this location. The fusion of the postoperative facial scan and preoperative facial prediction was found to be coincident. This technique can effectively predict facial aesthetic features of patients with maxillofacial trauma, facilitate communication with patients, reduce chairside time, and guide the multidisciplinary design of implant placement and restoration fabrication.

Novel model-less fully digital workflow for implant superstructures in an esthetic zone: A technical report.

This report introduces a fully digital workflow for the fabrication of implant superstructures in an esthetic zone using an intraoral scanner (IOS), computer-aided design/computer-aided manufacturing (CAD/CAM) technology, and monolithic multilayer zirconia. Digital impressions of scan bodies and occlusal registration were made in the esthetic zone using an IOS. The provisional restoration in the oral cavity was scanned, and the provisional restoration with an optimized surface morphology of the subgingival contour was scanned outside the oral cavity. These morphological data were integrated into the CAD software to generate a digital cast. The morphology of the final superstructure was generated based on morphological data of the provisional restoration. The final superstructure was fabricated from monolithic multilayer zirconia using a CAM machine, sintered, colored with a stain material, and subsequently bonded to a titanium base using resin cement. The superstructure was successfully fabricated using a model-less, fully digital workflow, and delivered to the patient. No clinical complications were reported. Thus, within the limitations of this report, the novel developed superstructure fabrication techniques can change the clinical and laboratory workflows from analog to digital in the esthetic zone.

Changes in digital cast measurements related with two types of rapid maxillary expanders, tooth-borne versus hybrid one

Objectives: This study compared digital study casts from tooth-borne and hybrid Rapid Maxillary Expansion (RME) using 3D virtual models scanned with a 3Shape laser scanner. Methods: A total of thirty patients with narrow maxilla were distributed into two equal groups using sequential randomization. The hybrid hyrax group (11 females and 4 males) had a mean age of 14.5 years, whereas the conventional hyrax group (10 females and 5 males) had a mean age of 13.96 years. Cone beam computed tomography and orthodontic casts were obtained before expansion and six months after the last activation. Eight parameters were measured, and the data was analyzed. Results: A paired t-test was used to evaluate the mean differences between pre-expansion and post-expansion measurements. Interdental distance (IDD) and rotations at first molar and premolars showed a statistically significant increase post-treatment compared to preoperative values, whereas arch depth and incisor inclination showed a statistically significant decrease. Furthermore, group B had statistically significant higher postoperative values and a greater IDD change (P≤0.05). Conclusion: RME with hybrid hyrax achieved skeletal effects and broaden the arch with only a slight increase in IDD compared to traditional RME. Regardless of the appliance, arch depth may be decreased following RME.

Preparing guiding planes for removable partial dentures: an in vitro comparison between assisted CAD-CAM template procedure and freehand preparation

ObjectivesTo compare the trueness of computer-aided design and computer-aided manufacturing (CAD-CAM) assisted procedure and freehand procedure for preparing guiding planes for removable partial dentures (RPDs). MethodsForty identical mandibular resin casts were divided into two groups in which the guiding planes of two abutment teeth were prepared freehand (control group, n = 20) and using rigidly constrained templates (test group, n = 20). The template was designed on a digital cast of virtually prepared guiding planes and fabricated by selective laser melting using cobalt-chromium alloy. To assess the 3D trueness, all prepared guiding planes (Test data) were digitized using a laboratory scanner and compared to the virtually designed guiding planes (Reference data). The angle deviation between the Test data and the designed direction of the path of placement was measured for assessing the direction trueness of guiding plane preparation. ResultsThe 3D trueness of guiding plane preparation was significantly better in the Test group (48.4 ± 12.9 μm) than in the Control group (128.5 ± 37.6 μm, p < 0.01). The direction trueness of guiding plane preparation was also significantly better in the Test group (1.20 ± 0.55°) than in the Control group (7.68 ± 3.00°, p < 0.01). ConclusionsThe CAD-CAM template assisted procedure can significantly improve tooth preparation of the guiding planes compared to the freehand preparation. The CAD-CAM template could help clinicians prepare parallel guiding planes in a predictable manner.