Examining the ability of artificial intelligence-driven occlusal contact adjustment to improve virtual occlusal record trueness for implant restorations: An in vitro study.

This study aimed to evaluate the effect of print orientation on the dimensional accuracy of attachments in directly 3D-printed orthodontic aligners. For n = 10 patients, 34 single-tooth aligner segments were digitally designed (17 for tooth 1.1 and 17 for tooth 1.6) incorporating a planned 3mm horizontal rectangular buccal attachment. These aligners were printed in TC-85 DAC resin (Graphy Inc, Seoul, Korea) at different inclinations (8 in anterotation and 8 in postrotation, at 10° intervals from the horizontal) and used as templates to transfer attachments onto corresponding 3D-printed dental models. This models with transferred attachments were scanned with a laboratory scanner and superimposed onto the attachment surface of the master digital file. Percentage volume deviations of the transferred versus planned attachment were quantified using Geomagic Control software (v.2020.1.1, ©2020 3D Systems, Inc., Rock Hill, SC) and analysed with an unpaired two-tailed t-test (P < 0.05). For tooth 1.1, the mean volumetric deviation of transferred attachments was significantly lower in postrotation orientations (88.87% ± 4.13) than in anterotation (69.01% ± 4.33), indicating that positioning the template with the vestibular surface facing the build platform improves accuracy (p < 0.0001). For tooth 1.6, no statistically significant difference was found (p = 0.0992; 78.16% ± 2.26 vs. 79.99% ± 1.87). Composite attachments transferred with 3D-printed templates exhibited a volumetric alteration respect the master digital file and print orientation particularly affects anterior teeth's attachments. Aligners orientation during 3D-printing is crucial to ensure accurate attachments transfer, especially anterior regions.

Background/Objectives: Accurate full-arch implant impressions are essential for predictable digital prosthodontics, yet the performance of different intraoral scanners (IOSs) remains variable. This in vitro study compared the trueness and precision of three widely used IOSs-Sirona Primescan, 3Shape TRIOS Core, and Medit i700-in a standardized full-arch implant model. Methods: A maxillary model with six multi-unit implants was digitized using a high-accuracy laboratory scanner to obtain the reference dataset. Each IOS was used to perform ten scans, exported as unmodified STL files. Accuracy was evaluated in Geomagic Control X through a two-step alignment and a peri-implant region-of-interest deviation analysis. Trueness (mean absolute surface deviation, µm) and precision (SD) were compared using one-way ANOVA with Tukey’s test (α = 0.05). Results: Primescan and TRIOS Core showed comparable trueness (202.76 ± 13.89 µm and 204.21 ± 2.61 µm, respectively), while Medit i700 demonstrated significantly higher deviations (221.05 ± 6.28 µm) (p < 0.05). TRIOS Core exhibited the highest reproducibility across repeated scans. Conclusions: The three scanners demonstrated measurable accuracy differences under standardized conditions. Primescan and TRIOS Core performed similarly in trueness, with TRIOS Core achieving superior precision. Medit i700 showed higher deviation values but remained consistent in its performance. These findings highlight measurable differences in accuracy and reproducibility among intraoral scanners under standardized laboratory conditions and may assist clinicians in selecting appropriate devices for full-arch digital implant workflows; however, clinical validation is required to confirm their performance in vivo.

Surface and linear scan accuracy of intraoral and extraoral photogrammetry systems: An in vitro study.

ObjectiveThe study focused on drawing a comparative evaluation amongst four commercially available implant luting cements used to retain implant-supported zirconia restorations fabricated using a Computer-Aided Design-Computer-Aided Manufacturing (CAD-CAM) system.Materials and methodsA heat-activated polymethyl methacrylate (PMMA) model was fabricated to mount four implant abutment-analogue complexes. These complexes were scanned using a digital laboratory scanner to mill 60 zirconia copings using CAD-CAM software. The copings were divided into four groups depending on the type of implant luting cement used (n = 15). The zirconia copings were then cemented over titanium abutments and a tensile load at a crosshead speed of 1 mm/min was applied to the samples to perform a pull-out test using Universal Testing Machine. Thereafter, the load required to de-cement each coping was obtained, thus the retention for each coping was measured.Statistical analysisOne-way analysis of variance (ANOVA) was advocated to statistically analyse the results and the post hoc Bonferroni test was used for multiple comparison using Statistical Package for the Social Sciences (SPSS) software.ResultsMultilink implant showed highest tensile strength (2.24 ± 1.01 kgf/mm2) being statistically significantly different from the other three cements (p < 0.001). This was followed by TgImplaCem (0.82 ± 0.32 kgf/mm2) and Temp-Bond NE (0.71 ± 0.13 kgf/mm2). The lowest tensile strength was exhibited by ImplaLute (0.31 ± 0.10 kgf/mm2). Intergroup comparison between TgImplaCem, Temp-Bond NE, and ImplaLute cements did not show statistically significant difference in tensile strength values (p < 0.001).ConclusionIt was concluded that both non-eugenol zinc oxide provisional luting cement (TgImplaCem) and dual-curing resin-based implant cement (Temp-Bond NE) can be advocated to cement implant-supported prostheses since they both permit adequate retention with ease of retrievability.

Objectives: The aim of this in vitro study was to evaluate the accuracy of intraoral impressions obtained using the Trios 3Shape® (3Shape Trios, Copenaghen, Denmark) and Carestream CS 3600™ (Carestream Dental, Stuttgart, Germany) scanners, compared with traditional polyvinyl siloxane (PVS) impressions. A laboratory scanner served as the gold standard. Materials and Methods: The study was based on 3D-printed master models derived from partially edentulous clinical cases previously treated at our department (2017–2022). All cases required at least two implants. Data analysis was performed using one-way ANOVA and two-sample Z-tests (α = 0.05) to compare mean deviations and variability. Results: All techniques demonstrated high accuracy, with deviations from the reference point below 30 μm. The digital intraoral scanners (Trios 3Shape® and Carestream CS 3600®) showed superior accuracy compared with PVS analog impressions, with no statistically significant difference between the two IOS systems. Conclusions: Within the limitations of this in vitro study, both IOS systems and PVS analog impressions achieved clinically acceptable accuracy. Digital systems exhibited improved performance in terms of mean deviation and consistency. The higher accuracy and consistency of digital impressions may translate into improved clinical efficiency and prosthetic fit in implant rehabilitations. From a clinical perspective, these in vitro findings suggest that digital impressions may enhance prosthetic fit and workflow efficiency, though further in vivo validation is required. Clinical significance: This study supports the reliability of intraoral scanning compared with conventional impressions in implant-supported rehabilitations. By demonstrating high intrinsic accuracy, these findings contribute to optimizing digital workflows in implant dentistry and reinforce the potential of intraoral scanning in static computer-guided, flapless implant surgery. Trial registration: Ethical approval and trial registration were not applicable to the present in vitro investigation, as no patients were directly involved in the experimental phase. The digital data used to generate the laboratory master models originated from a separate clinical study conducted at ASST Santi Paolo e Carlo, Milan (Ethics Committee approval no. 1361, 12 July 2017; ClinicalTrials.gov registration, Unique Protocol ID 1361).

Background/Objective. The objective of this study is to test the hypothesis that there is no significant difference between intraoral scanners and in-lab scanners. An additional objective is to test the hypothesis that there is no significant difference between the accuracy of two types of polyvinyl siloxane PVS impression materials and between PVS impression materials and intraoral scanners. Material and Methods. Fourteen subjects received a set of maxillary and mandibular removable complete dentures [RCD]. Impressions of each RCD were obtained using two PVS impression materials (heavy [H] or medium [M] body with light [L] body). Each RCD was then scanned utilizing two intraoral scanners, Trios [TR] and Omnicam [OM]. The PVS impressions were sent to the lab to be further scanned by an in-lab scanner. STL files of the intraoral and in-lab scans were obtained and trimmed using the GeoMagic X Software. The files were merged [TR vs. OM] and [TR vs. in Lab], [HL vs. ML], [HL vs. TR] and [ML vs. TR] and the gap was measured in sixty points for each merged file. Results. There was no significant difference between [TR vs. OM] with a mean of 44 ± 10 μm. There was a statistically significant difference between [TR vs. In lab] with a mean of 62 ± 21 μm and [ML vs. TR] and [HL vs. ML] with means of 66 ± 24 μm and 50 ± 21 μm, respectively. There was no significant difference between [HL vs. TR] with a mean of 37 ± 10 μm. Conclusions. Intraoral scanners provide a similar quality of scans. The lab scanner depends on the impression materials used. The first null hypothesis was rejected. Using a heavy and light body PVS impression material provides more accurate and dimensionally stable impressions, particularly in full-arch applications, and is comparable to intraoral scanners. The second null hypothesis was rejected, there were significant differences between the PVS groups. These findings guide clinicians in selecting impression methods for complete dentures.

High-speed sintering has emerged as a promising innovation for enhancing the efficiency of dental prosthesis fabrication. However, its impact on marginal adaptation remains a critical factor in ensuring the long-term clinical success of restorations. The aim of the study to evaluate the marginal fit of high-speed and regular-speed-sintered zirconia crowns. A maxillary right second molar on a typodont was prepared for an all-ceramic crown. A PVS impression was taken and a Type V stone master cast was fabricated. This cast was scanned via a laboratory scanner to produce 20 milled zirconia crowns. The crowns were divided into two groups (n = 10). Group A was subjected to a fast-sintering program, whereas group B was sintered via a conventional-speed-sintering program. Marginal fit was assessed via a stereoscopic microscope at four well-defined points (mid-distal, mid-lingual, mid-mesial, and mid-buccal) on each crown. Three readings were taken at each point. The marginal gaps of both groups were compared via the Wilcoxon signed-rank test. Statistically significant difference between groups A and B (p < 0.001) was revealed. Although the mean marginal gap in both groups was below the clinically acceptable limit (< 90μm), the fast-sintering program produced restorations with a larger marginal gap than the restorations sintered via the conventional program. Crowns produced via both sintering programs were clinically acceptable, although the regular-speed-sintering program yielded a significantly superior marginal fit.

Accuracy of single implant scans with an intermediate abutment-healing cap system. An in vitro study.

Background: The adoption of three-dimensional (3D) printing in dentistry for prosthetic workflows is increasing. A crucial step in the indirect fabrication of laminate veneers involves creating accurate master castsfrom digital impressions. However, there is limited information available regarding the accuracy of dental 3D printers in fabricating these master casts when different tooth preparation designs for laminate veneers are employed.Purpose: This study aimed to assess and compare the accuracy (trueness and precision) of dental 3D printers in fabricating master casts for laminate veneers featuring three different incisal edge preparationdesigns (butt-joint, window, and palatal extension).Materials and Method:This in vitro, experimental study was conducted on three dental models made of polyether ether ketone (PEEK) with central incisor and canine teeth with three incisal preparation designs of window,butt-joint, and palatal extension for fabrication of laminate veneers. The models were scanned by the same laboratory scanner, and the standard tessellation language (STL) files were printed byfour printers: Prodent (material jetting [MJ]), Asiga (digital light processing [DLP]), Hunter (DLP), and Luminous (light-emitting diode [LED]), 30 times. A total of 120 printed models were scannedagain, and their scan files in STL format were compared with the reference model file to assess the trueness and precision of the printers. Data were analyzed using paired and independent t-tests,one-way analysis of variance (ANOVA), and Tukey test (α= 0.05).Results: Asiga printer showed significantly higher trueness and precision than other printers (p< 0.05). No significant difference was found among other printers in trueness or precision(p> 0.05). The precision of window preparation design was significantly lower than other preparation designs (p< 0.05). No significant difference was found among other preparationdesigns in precision (p> 0.05). The difference in trueness was not significant among the preparation designs (p> 0.05).Conclusion: Asiga printer showed significantly higher trueness and precision than other tested printers for fabrication of laminate veneers. Also, window preparation of the incisal edge resulted in significantly lower precision than butt-joint and palatal extension designs.

Unifying intraoral scanner, computer-aided manufacturing, and final crown accuracy: A virtual-fit method for marginal gap evaluation.

Background and Objectives: This study aimed to investigate the effect of the intraoral scanner, scanning technique, and implant position on the trueness measured by linear and angular deviations. Materials and Methods: An edentulous maxillary model with four implants was scanned using four intraoral scanners (Trios 5, Trios 3, Primescan, Medit i700) and four scanning techniques (unmodified, composite, eugenol, dental floss). Each intraoral scanner–scanning technique combination was repeated ten times, producing 160 test datasets. Master reference files were generated with a laboratory scanner. Linear and angular deviations were calculated after superimposing each test scan with its master file. A three-way ANOVA followed by Tukey’s HSD test was used to determine statistical differences. Significance was set at p < 0.05. Results: Significant effects of intraoral scanner, scanning technique, and implant position were found for both linear and angular deviations (p < 0.001). Trios 5 showed the highest linear deviation values, although these remained within clinically acceptable limits, while Primescan showed the lowest. Dental floss produced the highest linear and angular deviations, whereas eugenol demonstrated the lowest. Medit i700 demonstrated the lowest angular deviation. Conclusions: All intraoral scanners showed deviations within clinically acceptable thresholds, although Trios 5 showed the highest linear deviation. Among scanning techniques, dental floss resulted in the highest linear and angular deviations. Deviations were lower between adjacent implants and higher across 1–3, 1–4, and 2–4.

Aim – to compare the accuracy of two intraoral scanners common in modern dentistry when scanning dentition with partial tooth loss in vitro; to guide dentists in choosing a scanner for use in clinical practice. Material and methods. The study compared two scanners: Medit I700 (Medit Corp, Seoul, South Korea) and TRIOS 3 (3Shape A/S, Copenhagen, Denmark). At the outset, 18 analog dental impressions of patients were taken, from which plaster models were cast. The models were scanned with a laboratory scanner (ATOS Blue Light Triple Scan III, 8 megapixels, 100 mm lens, GOM mbh, Braunschweig, Germany) to obtain reference scanning data. Next, 18 dental rows of the same patients were scanned on the compared intraoral scanners. The sets of all scan data were uploaded to software for three-dimensional accuracy assessment (Geomagic Qualify, 2013, Morrisville, NC). Results. The smallest standard deviation in accuracy measurements between the reference dataset and the various intraoral scanner datasets was obtained using the Medit I700 (0.142 mm). The lowest arithmetic mean of all deviations was found in the TRIOS 3 scanner (0.005 mm). On average, the TRIOS 3 scanner showed more accurate results. However, there were no statistically significant differences between the two Medit I700 and TRIOS 3 scanners (p 0.05). Conclusion. In this in vitro study, both oral scanners demonstrated clinically acceptable results in terms of accuracy.

To assess the influence of the color and diameter of retraction cords or Teflon tape and intraoral scanner (IOS) technology/system on the accuracy of crown preparations digitized using three IOSs. A typodont with a crown preparation with an equigingival finish line was digitized using a laboratory scanner (control). Three groups were created: i700, TRIOS 5, and Aoralscan3. Six subgroups were developed depending on the retraction method: no cord (NC subgroup), purple 00 cord (Knittrax 00; Pascal Dental) (00-K subgroup), yellow-black 00 cord (Ultrapack 00; Ultradent) (00-U subgroup), yellow 02 cord (Knittrax 02) (02-K subgroup), green 02 cord (Ultrapack 02) (02-U subgroup), and Teflon tape (T subgroup) (n = 10). The control scan was used as a reference to measure the root mean square (RMS) error discrepancies with each experimental scan on the preparation and margin areas. Two-way ANOVA and pairwise multiple comparisons tests were used to analyze trueness. Levene and pairwise comparisons tests were used to analyze precision (α = 0.05). In the preparation area, trueness differences were found among groups (p < 0.001) and subgroups (p < 0.001), with a significant group×subgroup interaction (p < 0.001). The i700 and Aoralscan3 and the 00-U, 02-U, and T subgroups had the best trueness. In the margin area, trueness discrepancies were found among groups (p < 0.001) and subgroups (p < 0.001). The Aoralscan3 and 02-U and T subgroups demonstrated the best trueness. Finally, precision discrepancies were found only in the preparation area among groups (p < 0.001) and subgroups (p < 0.001). The i700 and Aoralscan 3 groups and 02-U and T subgroups had the best precision. The IOS and retraction technique tested influenced the trueness and precision of the single tooth preparation cast. The color and diameter of the retraction cord or Teflon tape used as the first cord in the double cord technique for digitizing a crown preparation with equigingival finish line did impact the scanning accuracy of the IOSs tested. However, the scanning discrepancies measured are not clinically relevant.

ObjectiveThe goal of this study was to see how laser-sintered and regular cobalt-chromium bars affect how well they hold in place and how rough their surfaces are in lower jaw implant overdentures.Materials and MethodsThis study utilized a completely edentulous mandible model that was fabricated from epoxy resin. Implants were imbedded in the canine region in the model, then implant abutment were screwed on each implant. Scan bodies were inserted, then scanning of the 3D model was done using a laboratory scanner. CO-CR bars were divided into: Group A: Twelve bars that were fabricated using the laser sintering method. Group B: twelve bars were designed using CAD/CAM for the fabrication of a wax model, and then the bar was fabricated using a conventional lost wax-casting technique. Each bar and implant were loaded with a conventional acrylic resin denture. A universal testing machine was used to apply tensile load. Surface roughness was estimated by using a digital microscope with digital software. The data was collected and analyzed using statistical analysis.ResultsThere was a significant difference between group A and group B regarding the technique of fabrication of the implant bar in both retention and surface roughness.Conclusionchanging the technique for fabricating the implant bars has improved the retention and surface roughness of the implant-supported overdenture.

PurposeThis study aimed to evaluate the effect of implant angulation on the trueness and precision of intraoral scanning (IOS) using different prefabricated auxiliary device (PAD) designs and to compare the results with two photogrammetry (PG) systems.Materials and methodsThree master models with 5 implants were fabricated to simulate edentulous maxillary arches, featuring implant configurations including all implants parallel, one implant angulated 25° mesially, and one implant angulated 25° distally. Five digital impression techniques were evaluated: IOS (Cerec Primescan) without PADs (IOS), with crown-shaped PADs (IOS-C), with laterally extended PADs (IOS-LE), and two PG systems (ICam4D G3: PG-I, OxoCore: PG-O). Reference data were acquired using a laboratory scanner, and implant center coordinates in both reference and test datasets were determined in Geomagic Control X for deviation calculations. Linear deviations (LD), angular deviations (AD), and root mean squared error (RMS) values were calculated to assess trueness and precision, and were statistically analyzed.ResultsSignificant accuracy differences were observed between the PG systems, with PG-I exhibiting the lowest RMS values (18 ± 3.27 μm) across all models and maintaining deviations within clinically acceptable thresholds (P<0.01). IOS-LE showed significantly lower RMS and AD values compared to IOS and IOS-C. Implant angulation negatively affected the trueness of IOS, IOS-C, and PG-O, particularly with distal angulation (P<0.01), while PG-I and IOS-LE remained unaffected (P > 0.05). Implant angulation did not significantly affect precision (P = 0.328).ConclusionPG-I demonstrated the highest accuracy. Implant angulation compromised IOS trueness, but laterally extended PADs improved accuracy, making IOS comparable to PG systems.Clinical significanceThese findings indicate that, even in angulated full‑arch implant cases, photogrammetry (PG‑I) and IOS with laterally extended PADs provide clinically acceptable accuracy and may serve as reliable digital impression techniques in practice.

Dimensional stability of additively manufactured dental casts in bio-based resins: Influence of base design and storage conditions.

Comparison of wear behavior of occlusal device materials manufactured by different processes.

Effects of remaining tooth height and post space depth on the accuracy of a wireless intraoral scanner in post space scanning for maxillary incisor.

Despite the widespread use of surgical guides, there is no universal sterilization protocol. Surgical guides are often designed for single use, but can become contaminated, which increases the risks of infection and implant failure. This study evaluates the effects of alcohol immersion, alcohol spray, low temperature, and steam sterilization on the dimensional stability of surgical guides to ensure accurate implant placement and reduce failure. One standard dental model was scanned using a laboratory scanner. Ninety guides were printed and were then divided into six groups allocated as control, alcohol spray, alcohol immersion with ultrasonication, low-temperature dry sterilization, and two autoclave methods. Specimens were stored in dry–dark media and scanned at 0, 3, and 7 days, with dimensional changes assessed using CloudCompare. The Shapiro–Wilk, Levene’s, Repeated measures one-way ANOVA, and Tukey’s post hoc tests were used to determine statistical differences. Time significantly affects stability, with RMS values improving over time. Autoclave 121 °C and low-temperature 54 °C sterilization showed the lowest RMS values, indicating better stability. Within the limitations of the present study, the most effective approach for maintaining the dimensional stability of surgical guides was autoclaving at 121 °C, +1 bar for 20 min, and the second-best technique was low-temperature dry sterilization at 54 °C for 1 h.