Intraoral Scanner Research Articles

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

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

Novel digital technique for measuring the volumetric healing process of free gingival grafts surrounding dental implants

The objective of the present study was to analyze and describe a new digital technique for analyzing the volumetric healing process of free gingival grafts in both donor and recipient locations surrounding a dental implant, as well as to compare the reliability of conventional and digital techniques for measuring the width of the free gingival graft in the recipient location throughout the healing process.Materials and methodsTen patients presenting with mucositis linked to a dental implant were included. A preoperative soft tissue width &amp;lt;2 mm, with probing pocket depth &amp;lt;5 mm, edema and inflammation and bleeding on probing was determined A digital impression was taken of both donor and recipient locations using an intraoral scan, generating a Standard Tessellation Language digital file both preoperatively (STL1) and after 1 week (STL2), 1 month (STL3), 3 months (STL4), and 6 months (STL5) of follow-up. Afterwards, the digital files (STL1-STL5) were aligned using a reverse engineering morphometric software, and Student's t-test was used to analyze changes in volume at the donor and recipient locations. Additionally, widths were measured both clinically and digitally so as to compare the reliability of these measurement techniques. The repeatability and reproducibility of both these measurement techniques were also analyzed using Gage R&amp;amp;R statistical analysis.ResultsGage R&amp;amp;R found that total variability of the digital technique was 0.6% (among the measures of each operator) and 7.6% (among operators); as variability was under 10%, the results were repeatable and reproducible. In addition, there were statistically significant differences between donor and recipient locations in healing process volume (mm3) after one week (p = 0.0110), one month (p = 0.0007), three months (p &amp;lt; 0.0001) and six months (p = 0.0004) of follow-up.ConclusionThe digital measurement technique provided accurate, repeatable, and reproducible results when analyzing the volumetric and lineal measures of the healing process in both the donor and recipient locations of a free gingival graft surrounding a dental implant, with significantly higher tissue volume in the recipient location.

The effect of imaging programs and segmentation methods on the accuracy of volume measurements of teeth

ObjectiveThis study investigated whether there are differences between software programs, voxel sizes, segmentation techniques, and intraoral scanners in terms of volume measurement in incisor teeth. Study DesignThirty extracted teeth were scanned using a 3D intraoral scanner. Physical volumes were measured using the water displacement method (WDM) as the gold standard. Cone Beam Computed Tomography (CBCT) images were taken in two voxel sizes (0.3- 0.4 voxel). The volumes of the teeth were calculated using the manual segmentation technique in the 3D Doctor and ImageJ (Fiji) Program, manual and automatic segmentation methods in the ITK-Snap program, and automatic segmentation methods in the 3D Slicer program. The data were analyzed using the Statistical Package for Social Sciences (SPSS, v 20.0). ResultsThere is a significant difference between WDM and 3D Doctor volume measurements at the voxel size of 0.4 (p <0.05). The 3D Doctor program showed more than 13% difference compared to the WDM. There is no significant difference between WDM, intraoral scanner, ITK-Snap, ImageJ (Fiji), 3D Slicer, and 3D-Doctor volume measurements at the voxel size of 0.3. ConclusionMeasurements with manual segmentation in ITK-Snap and ImageJ programs give the closest results to the physical volume measurements of the teeth. The automatic segmentation method in ITK-Snap and 3D Slicer programs may be preferred due to its ease of use and less time consuming. In the 3D Doctor software, volume measurements tend to increase with larger voxel size. Statement of Clinical RelevanceDifferent software programs, voxel size, and segmentation techniques used in CBCT images affect the measurement results of tooth volumes. Very close to physical volume was obtained with the intraoral scanner. Measurements obtained through manual segmentation yield more accurate results.

In Vitro Comparative Analysis of Digital Versus Conventional Impressions in Fixed Prosthodontics

ABSTRACT Background: In the realm of fixed prosthodontics, the transition from conventional to digital impressions has been a subject of ongoing debate. This study aims to provide a comparative analysis of digital versus conventional impressions in terms of accuracy and efficiency. Materials and Methods: Twenty patients requiring fixed prosthodontic treatment were selected for this study. Each patient received both digital and conventional impressions. The digital impressions were obtained using an intraoral scanner, while conventional impressions were taken using polyvinyl siloxane material. The impressions were then used to fabricate fixed prostheses for each patient. Accuracy was assessed through measurement of marginal fit using a standardized technique, and efficiency was evaluated based on time taken for impression procedures. Results: The mean marginal discrepancy for digital impressions was found to be 38 micrometers (±5), whereas for conventional impressions, it was 45 micrometers (±7). Additionally, the average time taken for digital impressions was 12 minutes, compared to 20 minutes for conventional impressions. Conclusion: Digital impressions demonstrated superior accuracy and efficiency compared to conventional impressions in fixed prosthodontics.

Efficacy of clear aligners vs rapid palatal expanders on palatal volume and surface area in mixed dentition patients: A randomized controlled trial

This study aimed to evaluate the efficacy of Invisalign First Phase I treatment compared with tooth-borne rapid maxillary expansion (RME) in mixed dentition patients by examining changes in palatal volume, palatal surface area, and maxillary interdental transverse measurements. In this open-label, 2-arm, parallel, randomized controlled trial, patients with a posterior transverse discrepancy≤6 mm were allocated into the clear aligner therapy (CAT) group (Invisalign First Phase I treatment) and RME group (tooth-borne RME) according to a computer-generated randomization list immediately before the start of treatment. Digital models were obtained before the beginning of the treatment (T0) and at the end of the retention period/treatment (T1) using an intraoral scanner. Palatal volume was measured as the primary outcome, and palatal surface area and intermolar and intercanine transverse widths at the cusps and gingival level were measured as secondary outcomes. Patients and interventionists were not blinded because of the nature of the intervention. Out of 50 patients, 41 (19 males and 22 females; mean age, 8.12 ± 1.53 years) were enrolled and divided into 2 groups: 20 in the CAT group and 21 in the RME group. Two participants did not receive the allocated intervention for different reasons (1 patient discontinued the intervention in the CAT group, and another patient was lost to follow-up in the RME group). Thus, 19 patients (5 males and 14 females; mean age, 8.48 ± 1.42 years) were analyzed from the CAT group, and 20 patients (12 males and 8 females; mean age, 7.83 ± 1.19 years) from the RME group. Regarding intragroup comparisons, all outcome measures significantly increased from T0 to T1 in both groups. In terms of intergroup comparisons, there were no significant differences in the variation (Δ) of outcome measures between the 2 groups from T0 to T1, except for the intermolar width at the gingival level (P<0.005). The change in palatal volume was 532.01 ±540.52 mm³ for the RME group and 243.95 ± 473.24 mm³ for the CAT group (P = 0.084), with a moderate effect size (d = 0.57). RME showed trends favoring better outcomes compared with Invisalign First Phase I treatment across all assessed measures. The only parameter that showed statistically significant differences between the 2 groups was variation in intermolar width at the gingival level, suggesting the occurrence of buccal tipping in patients undergoing Invisalign First Phase I treatment. The trial was registered at ClinicalTrial.gov (no. NCT04760535).

Digital Comparison of Occlusal Vertical Contacts Between Direct Composite and Indirect Cad/Cam Restorations: An in vivo quantitative assessment

Objective: Clinical assessment of the static occlusal vertical contacts for direct composite and indirect Cad/Cam restorations, and evaluation of the clinical experience level's effect on contact registration. Methods: Sixty restorations on maxillary and mandibular molar teeth were investigated. Postgraduate students performed indirect Cad/Cam restorations (Cerasmart, GC Corp., n=20), and both undergraduate and postgraduate students performed direct composite restorations (Ganeial A’chord, GC Corp., n=20 for each). A single supervisor digitally analyzed the occlusal vertical contacts immediately after by using an intraoral scanner (iTero Element-5D, AlignTech) and OrthoCAD software. The tightness of contacts was assessed by counting the pixel numbers in Photoshop CC (Adobe) software. The statistical analyses were performed by Shapiro-Wilk, One-way ANOVA, Tamhane’s T2 test, Kruska-Wallis test, and Dunn tests (p

Effect of preparation design and scan pattern on the accuracy of intraoral scans for complete arch laminate veneers under simulated intraoral variables.

The purpose of the study was to investigate the influence of different preparation designs and scan patterns on the accuracy of intraoral scans for complete-arch maxillary laminate veneers. Three maxillary typodonts were used to obtain reference models with three different laminate veneer preparation designs: windows (W), beveled (B), and incisal overlap (IO). Reference scans were obtained with a desktop scanner. A total of 90 complete arch intraoral scans were made with an intraoral scanner (Medit i700) following three different scan patterns: straight motion (SM), zigzag motion (ZM), and combined motion (CM). Ten scans were made in each subgroup and exported as standard tessellation language (STL) files. Assessment of accuracy was conducted with a 3D software analysis program (Geomagic Control X). Each STL file was individually aligned with the reference scan using the best fit algorithm tool, and 3D differences were calculated using the root mean square (RMS) value. Two-way analysis of variance (ANOVA) followed by post hoc comparison tests were applied to analyze precision and trueness data (α = 0.05). Two-way ANOVA and post hoc comparison tests revealed significant differences among different preparation designs and scan patterns (p < 0.05). Regarding trueness, the IO when scanned with SM presented higher mean RMS than the other preparation designs (W and B) scanned with the same scanning pattern (p < 0.05). Regarding precision, the groups of W and IO presented significantly higher mean RMS than the group of B when scanned with ZM (p < 0.05). Accuracy of intraoral scans for complete-arch laminate veneers was affected by different laminate veneer preparation designs and scan patterns. Modifying scan pattern according to preparation design helps to improve scan accuracy for complete-arch laminate veneers.

Implementation of Patient-Individualized 3D-Printed Models in Undergraduate Students' Education for Various Prosthetic Treatments: A Cross-Sectional Survey Study.

Due to rapid changes in dental practice, digital technologies have become prominent in undergraduate dental education at German universities in recent years. This shift has prompted a re-evaluation of content as well as teaching methods, particularly in courses where students are prepared for patient treatment. Traditional training on standardized models with resin teeth cannot cover the complexity of individual dental arch configuration encountered in patient situations. This study explores the use of 3D printing technology to create individualized models for prosthetic treatment simulations, aiming to evaluate students' feedback towards their experience with this training setting. First, the study describes the design and fabrication of individualized models with exchangeable teeth based on intraoral scans, mounted on connected plates with distance holders that can be fixed to standard phantom heads. Second, students provided feedback through a questionnaire, assessing various aspects such as the effectiveness of the 3D-printed models compared to traditional frasaco models for preparation exercises. The results indicated that the design of the realized models was feasible for preparation training (question no. 4: 93% positive rating) and showed positive perceptions of the 3D-printed models, with students finding them effective for preparation exercises and beneficial in bridging the gap between simulation and real patient situations (question no. 6: 69% positive rating). The study suggests that 3D printing technology offers a valuable tool in dental education, providing realistic and patient-specific scenarios for students to enhance their skills and readiness for clinical practice. Further improvements in material properties in hand with cost-effective approaches are essential for widespread implementation.

Evaluating the accuracy of one-piece and three-piece 3D-printed indirect bonding transfer trays: An in vitro study.

Recent developments in computer-aided design/computer-aided manufacturing (CAD/CAM) and 3D printing have enabled the fabrication of digital indirect bonding (IDB) transfer trays. These modern products require thorough investigation. The aim of the study was to determine the accuracy of one-piece and three-piece IDB transfer trays in vitro. An initial dental scan (IDS) of a randomly selected patient with digitally positioned brackets served as the master scan (MS) for designing 16 IDB transfer trays of each type. They were 3D printed and used for bonding 448 brackets to the models. Subsequently, the models were scanned with a TRIOS® 3 Intraoral Scanner (3Shape A/S, Copenhagen, Denmark), producing actual scans (ASs). The accuracy of bracket positioning was measured digitally on both MSs and ASs. The measurements were compared to the Objective Grading System for dental casts provided by the American Board of Orthodontics (ABO). The 2 types of IDB transfer trays showed comparable accuracy. All linear errors were within the clinically acceptable range, whereas the angular measurements demonstrated significant variability, resulting in clinically unacceptable transfer errors that ranged from 3.3% to 90.3%. The study results cannot be unconditionally extrapolated to other types of IDB transfer trays due to the diversity of their properties and features. The study evaluated the in vitro accuracy of IDB transfer trays. The revealed number of errors may be even higher in vivo due to limitations in visibility, salivary flow, interference from the tongue, and difficulties in achieving a proper fit of the IDB transfer tray to the teeth.

Relationship between the mandibular curve of Spee and the maxillary compensating curve with dentoskeletal morphology : Across-sectional study in Chinese young adults with normal occlusion.

The purpose of this cross-sectional study was to use multiple regression analysis to evaluate the relationship between the mandibular curve of Spee (COS) and the maxillary compensating curve with dentoskeletal morphology in young Chinese adults with normal occlusion. This study comprised 62young adults (31males, mean age: 24.1 ± 2.2years; 31females, mean age: 23.3 ± 3.3years) with Angle classI normal occlusion. For every subject, intraoral scan models of the maxillary and mandibular arches and lateral cephalograms were acquired. The depth of the COS and compensating curve were assessed on the intraoral scan models. Multiple dental arch dimensional and cephalometric variables were screened by univariate analysis. Subsequently, amultiple linear regression model (forward stepwise selection) was constructed to determine which variables were significantly correlated with the two curve depths. In the mandible, the COS depth was deepest at the mesiobuccal cusp of the first molar. Overjet, mandibular arch width and mandibular-occlusal plane angle significantly correlated with the COS depth (P < 0.05), accounting for 33.1% of the variation in the mandibular COS. In the maxilla, the deepest point of the compensating curve was at the distobuccal cusp of the first molar. Mandibular arch perimeter and overbite significantly correlated with the maxillary compensating curve (P < 0.05), explaining 23.3% of the variation. Overjet, overbite, mandibular-occlusal plane angle, mandibular arch width and perimeter should be considered when reconstructing occlusal curves in clinical orthodontic treatment and in prosthetic restoration.

The effect on the performance of a dynamic navigation system of superimposing a standard tessellation language (STL) file obtained with an intraoral scan on a cone beam computer tomograph (CBCT). An experimental in vitro study

ObjectivesTo compare the accuracy and operative time of implant placement using a dynamic computer assisted implant surgery (dCAIS) system based on a cone beam computer tomography (CBCT) image, with and without superimposing a standard tessellation language (STL) file of an intraoral scan of the patient. MethodsTen identical resin models simulating an upper maxilla with posterior edentulism were assigned to two groups. In the CBCT+STL group, a CBCT file and an intraoral STL file were superimposed and used for registration; in the CBCT group, registration was performed using CBCT images. Six implants were placed in each model using the Navident® dynamic navigation system. Anatomy registration was performed by tracing fiducial points on the CBCT or STL image, depending on the group. Preoperative and postoperative CBCT images were overlaid to assess implant placement accuracy. ResultsSixty implants were analyzed (30 implants in each group). 3D platform deviation was significantly lower (mean difference (MD): 0.17 mm; 95 % confidence interval (CI): 0.01 to 0.23; P = 0.039) in the CBCT+STL group (mean: 0.71 mm; standard deviation (SD): 0.29) than in the CBCT group (mean: 0.88 mm; SD: 0.39). The remaining accuracy outcome variables (angular deviation MD: -0.01; platform lateral deviation MD: 0.08 mm; apex global MD: 0.01 mm; apex depth MD: 0.33 mm) and surgery time (MD: 3.383 min.) were similar in both groups (p > 0.05). ConclusionsThe introduction of an intraoral scan (STL) seems to reduce deviations slightly in dental implant placement with dCAIS systems. However, the clinical repercussion of this improvement is questionable. Clinical significanceSuperimposing an intraoral scan on the CBCT image does not seem to increase the accuracy of dCAIS systems but can be useful when radiographic artifacts are present.

Novel AI-based automated virtual implant placement: Artificial versus human intelligence

ObjectivesTo assess quality, clinical acceptance, time-efficiency, and consistency of a novel artificial intelligence (AI)-driven tool for automated presurgical implant planning for single tooth replacement, compared to a human intelligence (HI)-based approach. Materials and methodsTo validate a novel AI-driven implant placement tool, a dataset of 10 time-matching cone beam computed tomography (CBCT) scans and intra-oral scans (IOS) previously acquired for single mandibular molar/premolar implant placement was included. An AI pre-trained model for implant planning was compared to human expert-based planning, followed by the export, evaluation and comparison of two generic implants—AI-generated and human-generated—for each case. The quality of both approaches was assessed by 12 calibrated dentists through blinded observations using a visual analogue scale (VAS), while clinical acceptance was evaluated through an AI versus HI battle (Turing test). Subsequently, time efficiency and consistency were evaluated and compared between both planning methods. ResultsOverall, 360 observations were gathered, with 240 dedicated to VAS, of which 95 % (AI) and 96 % (HI) required no major, clinically relevant corrections. In the AI versus HI Turing test (120 observations), 4 cases had matching judgments for AI and HI, with AI favoured in 3 and HI in 3. Additionally, AI completed planning more than twice as fast as HI, taking only 198 ± 33 s compared to 435 ± 92 s (p < 0.05). Furthermore, AI demonstrated higher consistency with zero-degree median surface deviation (MSD) compared to HI (MSD=0.3 ± 0.17 mm). ConclusionAI demonstrated expert-quality and clinically acceptable single-implant planning, proving to be more time-efficient and consistent than the HI-based approach. Clinical significancePresurgical implant planning often requires multidisciplinary collaboration between highly experienced specialists, which can be complex, cumbersome and time-consuming. However, AI-driven implant planning has the potential to allow clinically acceptable planning, significantly more time-efficient and consistent than the human expert.

3D printed indirect bonding trays: transfer accuracy of bar vs shell design in a prospective, randomized clinical trial.

To compare the transfer accuracy of two different indirect bonding (IDB) trays. Digital IDB was performed on a total of 30 patients using one of two designs: shell and bar trays, with 15 patients in each group. Trays were designed with the Appliance Designer software (3Shape A/S, Copenhagen, Denmark). Angular (torque, tip, angulation) and linear (mesiodistal, buccolingual, occlusogingival) differences were compared between the bonded intraoral scans taken immediately after IDB and the virtually bracketed model prepared in Ortho Analyzer software (3Shape A/S) using open source GOM inspect software (GOM GmbH, Braunschweig, Germany). There were no significant differences found between the bar and shell groups. Within the groups, significant tip differences were found between the incisors, canines, and premolars in both groups (P = .0001). Additionally, a statistically significant torque difference was found in the canines and incisors in the shell group. The percentage of values that deviated from the clinical acceptance limit was relatively higher in the bar group. Although there was no statistical difference between groups, the shell tray showed better results according to clinical acceptability limits. This study is important as it is the first clinical study to compare directly printed transfer trays with different designs.

Efficacy of Conventional versus Cordless Displacement System on Gingival Retraction for Use with Intra-Oral Scanner: A Clinical Study.

The present clinical study aimed to assess the efficacy of conventional versus cordless displacement systems on gingival retraction for use with an intra-oral scanner and changes in periodontal indices. A total of 20 participants were selected for a split-mouth study (20 sites - Group Sc, 20 sites - Group Es). The outcomes were measured at day 0, day 1, and day 7 of follow-up in terms of Immediate horizontal displacement, Plaque Index, and Bleeding Index. Unpaired and Paired t-test was used as the parametric tests and statistical analysis was performed. A statistically significant change was observed in terms of BI on day 0, but no statistically significant change was observed for either group in terms of IHD and PI. The cordless material caused the least trauma to gingival tissue and was more compatible with intra-oral scanning devices.

Computer-assisted open exposure of palatally impacted canines for orthodontic eruption: A randomized clinical trial

ObjectiveThis randomized clinical trial aimed to assess the feasibility of computer-assisted open exposure of palatally impacted canines. Materials and methodsPatients aged 11–30 years who required orthodontic eruption for the full palatal impaction of their canines were included in this study. Exclusion criteria were psychosocial and dental contraindications of orthodontic treatment, congenital craniofacial disorders, and trauma in the patient's history in the vicinity of the surgical site. Virtual planning software was used to register the intraoral scans and cone-beam computed tomography data and to design a surgical template. In the test group, exposure of the canines was guided by a surgical template, whereas in the control group, the surgeon relied on the surgical plan to localize the impacted canine. The success of the intervention, duration of surgery, and complications, including excessive hemorrhage, damage to the canine or neighboring anatomical landmarks, and postoperative inflammation of the surgical site were assessed. Postoperative pain was reported by the patients using the visual analog pain scale (VAS). ResultsSurgery was deemed successful in all patients in both groups. During healing, no complications were observed. The duration of surgery decreased significantly in the test group (4 min 45.1 s ± 1 min 8.4 s) compared to that in the control group (7 min 22.3 s ± 56.02 s). No statistically significant differences were observed between the VAS scores of the two study groups. ConclusionsThe application of virtual planning and static navigation is a viable approach for the open exposure of palatally impacted canines. Clinical trial registration numberNCT05909254. Clinical significanceComputer-assisted surgery is a feasible method for open exposure of palatally impacted canines, which decreases the duration of surgery compared to the freehand method.

Digital workflow feasibility for the fabrication of intraoral maxillofacial prosthetics after surgical resection: a systematic literature review.

To evaluate the current evidence of digital workflow feasibility based on the data acquisition methods and the software tools used to fabricate intraoral prostheses for patients with partial or total maxillary and mandibular defects. An electronic search was performed in PubMed, SCOPUS, and Web of Science using a combination of relevant keywords: digital workflow, digital designing, computer-assisted design-computer aided manufacturing, 3D printing, maxillectomy, and mandibulectomy. The Joanna Briggs Institute Critical Appraisal Tool was used to assess the quality of evidence in the studies reviewed. From a total of 542 references, 33 articles were selected, including 25 on maxillary prostheses and 8 on mandibular prostheses. The use of digital workflows was limited to one or two steps of the fabrication of the prostheses, and only four studies described a complete digital workflow. The most preferred method for data acquisition was intraoral scanning with or without a cone beam computed tomography combination. Currently, the fabrication process of maxillofacial prostheses requires combining digital and conventional methods. Simplifying the data acquisition methods and providing user-friendly and affordable software may encourage clinicians to use the digital workflow more frequently for patients requiring maxillofacial prostheses.

How does the consecutive use of intraoral scanners affect musculoskeletal health? A preliminary clinical study

BackgroundMinimizing muscle strain and reducing the risk of musculoskeletal disorders associated with intraoral scanner (IOS) usage require ergonomic awareness, device selection, and workplace adjustments in dental practice. This preliminary clinical study aimed to simulate intraoral scanning tasks using wired and wireless IOSs and assess muscle activation and fatigue for both types.Materials and methodsFourteen participants performed intraoral scanning tasks using wired and wireless IOSs (i700; MEDIT), with weights of 280 g and 328 g, respectively. The same computer system and software conditions were maintained for both groups (N = 14 per IOS group). Electrodes were placed on arm, neck, and shoulder muscles, and maximal voluntary contraction (MVC) was measured. Surface electromyography (EMG) was performed during the simulation, and EMG values were normalized using MVC. The root mean square EMG (%MVC) and muscle fatigue (%) values were calculated. Statistical comparisons were performed using the Mann–Whitney U and Friedman tests, with the Bonferroni adjustment for multiple comparisons (α = 0.05).ResultsArm (flexor digitorum superficialis) and neck muscles (left sternocleidomastoid and left splenius capitis) showed significantly higher EMG values with wireless IOS (P < 0.05). The neck (left sternocleidomastoid and right levator scapulae) and shoulder muscles (right trapezius descendens) demonstrated significantly higher muscle fatigue with wireless IOS (P < 0.05).ConclusionsThe consecutive use of heavier wireless IOS may increase the risk of muscle activation and fatigue in certain muscles, which may have clinical implications for dentists in terms of ergonomics and musculoskeletal health.

Predictability of expansion movements performed by clear aligners in mixed dentition in both arches: a retrospective study on digital casts

Backgroundto evaluate the predictability of expansion achieved in patients in early mixed dentition treated with Clear Aligners (CA), analyzing the efficiency of the expansion at the end of the first set of aligners and at the end of the therapy in the upper and lower arch.Methods36 patients (20 F, 16 M; mean age 8.3 ± 1.5 years) were selected retrospectively from the Department of Orthodontics of the Hospital of Rome “Tor Vergata”. All subjects were treated with CA with no other auxiliaries than attachments. For each patient a standardized sequential expansion protocol was planned for both arches. Digital dental casts were created at three observation periods from an intraoral scanner: prior to treatment (T0), at the end of the first set of aligners (T1), at the end of treatment (T2). The 3D models in planned position determined by the first Clincheck (CC) were obtained for comparison with T1 and T2. Six linear transversal measurements were used to evaluate the dimensional changes and the predictability of expansion movements, comparing T1-CC and T2-CC.Resultsa statistically significant increase within the pre-treatment and the final outcomes for all the variables examined was found. In the upper arch, the greatest level of predictability was detected at the level of the first (46.44%) and second deciduous molar width (44.95%) at T1. The analysis of T2-CC changes showed a significant increase in the percentage of predictability of expansion at the level of the first permanent molars, at mesial (54.86%) and distal (58.92%) width. In the lower arch, a higher percentage of predictability than the upper arch was reported at T1-CC and T2-CC, with the greatest values at the level of second (T1-CC: 48.70%; T2-CC: 75.32%) and first deciduous molar width (T1-CC: 45.71%; T2-CC: 72.75%).ConclusionsCA can induce significant transversal increments. The predictability of expansion is variable, but it did not exceed the 50% during the first set of aligners. It was necessary to apply refinement set to achieve a good predictability for expansion of about 70%. The expansion in the lower arch was observed to be more predictable than in the upper arch.

Effect of different instrumental techniques and clinical experience on shade matching.

Many factors can affect the aesthetics of dental restorations, including the instrumental techniques used in shade matching, and can lead to clinical failure. The aim of this study was to investigate the effectiveness of using the cross-polarization digital photograph technique and intraoral scanners for shade matching, and also evaluate the effect of the level of clinical experience on shade matching success. Color analysis was performed on the maxillary right central incisors of 10 subject models with Vita Easyshade. Intraoral scanning was performed 10 times on each model using TRIOS 3 and color analysis was performed from the same spot. Then cross-polarized and non-polarized photographs of the models were taken with standard settings using a gray reference card. Each shade tab of the Vita System 3D-Master scale was also photographed with two different polarization techniques. Four groups (n = 12), including prosthodontics faculty staff, postgraduate students in prosthodontics, undergraduate students, and dental technicians matched the shade tabs and the model photographs obtained with both techniques on a standardized computer screen. Finally, the color differences between the shade tabs and maxillary central incisors matched by observers from four different groups were recorded using a colorimeter, Classic Color Meter, in accordance with the CIELAB system and CIEDE2000 (ΔE00) values were calculated. The data were compared with the acceptability threshold of 1.80 for ΔE00. The data obtained from the observers were analyzed with IBM SPSS Statistics 26.0 Release Notes program. Independent Samples t-test was used to compare normally distributed data according to binary groups. The level of significance was 0.05. A statistically significant difference was found in the shade matching on photographs taken with different techniques in postgraduate students (p = 0.02). Also, there was a statistically significant difference in success between the groups that made shade matching based on photographs obtained with the non-polarization technique (p = 0.00). The undergraduate students achieved statistically significantly lower results than all other groups (ΔE00 = 5.57±1.07). The kappa value between the intraoral scanner and spectrophotometer results was 0.10, and this value was not statistically significant (p = 0.32). The cross-polarization technique used especially for shade matching is not superior to the non-polarization technique. Academic and clinical experience might be correlated with shade-matching success with the non-polarization technique. The clinical acceptability threshold could not be achieved in the shade matchings made on digital photographs taken with both techniques. Shade matching performed with an intraoral scanner did not yield reliable results.

Digital intraoral and radiologic records in forensic identification: Match with disruptive technology

While clinical dentistry has seamlessly integrated the digital revolution, there is a gap in the technological capabilities of forensic dentistry.The study aimed to compare the superimposition accuracy of two different three-dimensional record formats, namely the intraoral scanner and cone beam computer tomography, in the context of forensic identification.The sample consisted of randomly selected adults (n=10) of both sexes aged between 20 and 50 years. Following the acquisition of data using the Medit i700 wireless scanner and the iCAT Tomograph with InVivo software, the records were analysed and compared through superimposition using Medit Scan Clinic software to assess the technical precision of anatomical identification details.The results obtained through the superimposition of dental and bone records following intra- and inter-observer analysis enabled an accurate comparison and identification of an individual. This method can differentiate between positive and negative matches, achieving exclusion results and offering a potential solution to overcoming the absence of a standardisation procedure in human identification.