Workflow of a fiber-reinforced composite fixed dental prosthesis by using a 4-piece additive manufactured silicone index: A dental technique

True horizontal or gravity plane registration for transferring the maxillary scan into the virtual articulator by using a facial scanner without the need for an additional device

Different reference planes can be used to transfer the maxillary cast into the analog articulator, including the true horizontal or gravity reference plane. Different techniques have been described to record the gravity reference plane for transferring the maxillary scan into the virtual articulator by using facial scanning techniques. However, these digital facebow procedures require the use of an extraoral scan body system, printed reference device, or orientation reference board. This manuscript describes a technique for recording the gravity reference plane by using a facial scanner without the use of an additional device. This technique aims to reduce the clinical time needed to capture a patient's digital data and minimize the laboratory time needed to integrate the virtual patient and transfer the maxillary scan into the virtual articulator.

Digital maxillomandibular relationship and mandibular motion recording by using an optical jaw tracking system to acquire a dynamic virtual patient

A technique for digitally recording the maxillomandibular relationship, including the maximum intercuspation and centric occlusion and the patient's mandibular motion, by using an optical jaw tracking system is described. Advantages of this technique include the digital registration of the maxillomandibular relationship and mandibular motion. This technique incorporates the mandibular motion into the 3-dimensional (3D) virtual patient representation to integrate the 3D dynamic virtual patient visualization.

Accuracy of the 3-dimensional virtual patient representation obtained by using 4 different techniques: An in vitro study

STATEMENT OF PROBLEM

Facial and intraoral scans can be aligned with or without the assistance of extraoral scan body systems to obtain a 3-dimensional (3D) virtual patient representation. However, the accuracy of the virtual patient remains uncertain.

PURPOSE

The purpose of this in vitro study was to measure the accuracy of the virtual patient representation obtained by superimposing facial and intraoral digital scans with 4 different techniques (with and without the usage of extraoral scan bodies) and to measure the operator influence on the accuracy of the virtual patient integration.

MATERIAL AND METHODS

Three markers were placed in the jaw simulation of a mannequin on the right (r), center (c), and left (l) surfaces. Five additional markers were attached to the mesiobuccal cusp of the right first molar (RM), cusp of the right canine (RC), buccal surface of the right central incisor (CI), cusp of the left canine (LC), and mesiobuccal cusp of the left first molar (LM). A reference scan (control scan) of the mannequin was obtained by using an industrial scanner (Gom ATOS Q 3D 12 M). Four different groups were created depending on the technique used: 3D scan body (3D scan body) (3D-SB group), AFT (AFT Dental System) (AFT group), Sat 3D (Sat 3D) (Sat3D group), and without using a scan body system (No-SB group). Additionally, a digital scan of the typodont was obtained with an intraoral scanner (TRIOS 4). The virtual patient integration was performed 10 times per group by 2 independent operators by using a software program (DentalCAD, Galway). Each operator obtained a total of 9 interlandmark measurements on the reference scan and on each virtual patient integration of each group with the measurement tool of the computer-aided design program. The data were analyzed by using 4-way ANOVA followed by the pairwise comparison Tukey tests (α=.05).

RESULTS

The group (P<.001), specimen (P<.001), and operator (P<.001) significantly influenced the trueness discrepancies obtained. Additionally, the 3D-SB group had the best trueness (244 μm), and the No-SB group had the worst trueness (346 μm). Operator 1 (279 μm) obtained significantly better trueness than operator 2 (295 μm). Group (P<.001), specimen (P<.001), and operator (P<.001) significantly influenced precision discrepancies, with the AFT (149 μm) and 3D-SB (154 μm) groups having the best precision and the No-SB group (269 μm) the worst precision. Operator 1 (176 μm) obtained significantly better precision than operator 2 (197 μm).

CONCLUSIONS

The techniques tested influenced the accuracy of the 3D virtual patient representation. The 3D-SB group had the best trueness, and the AFT and 3D-SB groups had the best precision, while the No-SB group showed the lowest trueness and precision values. Operator handling had a significant effect on the trueness and precision values of the virtual patient integrations tested.

Accuracy of the preparation depth in mixed targeted restorative space type veneers assisted by different guides: An in vitro study

PURPOSE

Most veneers are mixed targeted restorative space (MTRS)-type restorations that are partially within the original tooth and require inconsistent preparation depths. This study aimed to evaluate the accuracy of the preparation depth for MTRS veneer preparation.

METHODS

MTRS veneer preparation models were developed using the twisted maxillary central incisor (MCI) as the original tooth and the standard MCI as the waxing. Veneer preparations were performed using freehand (MF), silicone (MS), thermoplastic (MT), 3D-printed uniform (MD), and auto-stop (MA) guides. The prepared and original MCI were scanned and superimposed using a custom-made base. The mean absolute differences (MADs) were measured to evaluate the accuracy of the preparation depth. Statistical analysis was performed using the multivariate analysis of variance (MANOVA) test (α=0.05).

RESULTS

The accuracy of the preparation depth was 0.237±0.090, 0.191±0.099, 0.149±0.078, 0.093±0.050, and 0.059±0.040 mm in MF, MS, MT, MD, and MA, respectively. The MADs between the groups were significant (P<0.05). The accuracy of the trial restoration was 0.140±0.081 mm in the MS, and the accuracy of the guiding tube was 0.055±0.033, 0.036±0.011, and 0.033±0.010 mm in the MT, MD, and MA, respectively.

CONCLUSIONS

In MTRS veneer preparation for MCI, tooth preparation guides improved the accuracy of the preparation depth by visualizing the TRS profile and providing clear measurement points. The accuracy of the guide is influenced by its flexibility, and the accuracy of the preparation depth is affected by the accuracy of the measurement points.

Analysis of the impact of the facial scanning method on the precision of a virtual facebow record technique: An in vivo study

STATEMENT OF PROBLEM

Virtual facebow record techniques typically record the relationship of a maxillary digital scan to facial landmarks by aligning it to a 3-dimensional face scan. Three-dimensional face scans can be acquired with different facial scanning methods, but the impact of the facial scanning method on the accuracy (trueness and precision) of a virtual facebow record technique remains unclear.

PURPOSE

The purpose of this in vivo study was to assess the impact of the facial scanning method on the precision under the repeatability conditions (repeatability) of a virtual facebow record technique.

MATERIAL AND METHODS

Repeatability of the virtual facebow record technique with the following 3 clinical-grade facial scanning methods was determined and compared: a professional handheld scanner based on structured blue light scanning technology (PHS method); an attachment-type 3-dimensional sensor camera connected to a tablet and controlled with a mobile application (3DSC-T method); and a smartphone with an integrated 3-dimensional sensor camera controlled with a mobile application (3DSC-S method). To determine the repeatability of the virtual facebow record technique with each facial scanning method, 8 virtual facebow records of a completely dentate adult with class I occlusion and mesoprosopic facial form were obtained (8×3=24 in total); with these, 8 locations of a maxillary digital scan with respect to a common 3-dimensional face scan were obtained. Repeatability was determined in terms of deviations between located maxillary digital scans, determined, in turn, by calculating the distances between corresponding vertices for each of the possible nonrepeating combinations of pairs of located maxillary digital scans (8C2=28). Finally, the repeatability of the virtual facebow record technique with the different facial scanning methods was compared by using the Welch ANOVA test and the post hoc Games-Howell test (both α=.05).

RESULTS

The repeatability of the virtual facebow record technique with PHS, 3DSC-T, and 3DSC-S facial scanning methods resulted in 0.243 ±0.094 mm, 0.437 ±0.171 mm, and 1.023 ±0.399 mm, respectively. Comparison of these results revealed that the facial scanning method had a statistically significant effect on the repeatability of the virtual facebow record technique (P<.001) and that its repeatability was statistically significantly greater with the PHS facial scanning method than with the 3DSC-T and 3DSC-S facial scanning methods and greater with the 3DSC-T facial scanning method than with the 3DSC-S facial scanning method (P<.001 for all pairwise comparisons).

CONCLUSIONS

This study found that the facial scanning method had a great impact on the repeatability of the virtual facebow record technique and that the virtual facebow record technique was more repeatable with more accurate facial scanning methods.

The state of additive manufacturing in dental research - A systematic scoping review of 2012-2022

Background/purpose

Additive manufacturing (AM), also known as 3D printing, has the potential to transform the industry. While there have been advancements in using AM for dental restorations, there is still a need for further research to develop functional biomedical and dental materials. It's crucial to understand the current status of AM technology and research trends to advance dental research in this field. The aim of this study is to reveal the current status of international scientific publications in the field of dental research related to AM technologies.

Materials and methods

In this study, a systematic scoping review was conducted using appropriate keywords within the scope of international scientific publishing databases (PubMed and Web of Science). The review included related clinical and laboratory research, including both human and animal studies, case reports, review articles, and questionnaire studies. A total of 187 research studies were evaluated for quantitative synthesis in this review.

Results

The findings highlighted a rising trend in research numbers over the years (From 2012 to 2022). The most publications were produced in 2020 and 2021, with annual percentage increases of 25.7% and 26.2%, respectively. The majority of AM-related publications in dentistry research originate from Korea. The pioneer dental sub-fields with the ost publications in its category are prosthodontics and implantology, respectively.

Conclusion

The final review result clearly stated an expectation for the future that the research in dentistry would concentrate on AM technologies in order to increase the new product and process development in dental materials, tools, implants and new generation modelling strategy related to AM. The results of this work can be used as indicators of trends related to AM research in dentistry and/or as prospects for future publication expectations in this field.

Virtual 3-dimensional representation of a completely edentulous patient for computer-aided static implant planning

A technique is described to create a virtual 3-dimensional representation of an edentulous patient by aligning the facial, intraoral, and cone beam computed tomography scans guided by an additively manufactured scan body. Having the virtual patient facilitated the prosthetically driven implant planning, the additive manufacturing of the surgical implant guides, and the interim dental restorations.

A guide for maximizing the accuracy of intraoral digital scans. Part 1: Operator factors

OBJECTIVES

To describe the factors related to the operator skills and decisions that influence the scanning accuracy of intraoral scanners (IOSs). A new classification for these factors is proposed to facilitate dental professionals' decision making when using IOSs and maximize the accuracy and reliability of intraoral digital scans.

OVERVIEW

Each IOS system is limited by the hardware and software characteristics of the selected device. The operator decisions that can influence the accuracy of IOSs include the scanning technology and system selection, scanning head size, calibration, scanning distance, exposure of the IOS to ambient temperature changes, ambient humidity, ambient lighting conditions, operator experience, scanning pattern, extension of the scan, cutting off, rescanning, and overlapping procedures.

CONCLUSIONS

The knowledge and understanding of the operator factors that impact scanning accuracy of IOSs is a fundamental element for maximizing the accuracy of IOSs and for successfully integrating IOSs in daily practices.

CLINICAL SIGNIFICANCE

Operator skills and clinical decisions significantly impact intraoral scanning accuracy. Dental professionals must know and understand these influencing operator factors for maximizing the accuracy of IOSs.