An automatic tooth preparation technique: A preliminary study

Applications and performance of artificial intelligence models in removable prosthodontics: A literature review

PURPOSE

In this narrative review, we present the current applications and performances of artificial intelligence (AI) models in different phases of the removable prosthodontic workflow and related research topics.

STUDY SELECTION

A literature search was conducted using PubMed, Scopus, Web of Science, and Google Scholar databases between January 2010 and January 2023. Search terms related to AI were combined with terms related to removable prosthodontics. Articles reporting the structure and performance of the developed AI model were selected for this literature review.

RESULTS

A total of 15 articles were relevant to the application of AI in removable prosthodontics, including maxillofacial prosthetics. These applications included the design of removable partial dentures, classification of partially edentulous arches, functional evaluation and outcome prediction in complete denture treatment, early prosthetic management of patients with cleft lip and palate, coloration of maxillofacial prostheses, and prediction of the material properties of denture teeth. Various AI models with reliable prediction accuracy have been developed using supervised learning.

CONCLUSIONS

The current applications of AI in removable prosthodontics exhibit significant potential for improving the prosthodontic workflow, with high accuracy levels reported in most of the reviewed studies. However, the focus has been predominantly on the diagnostic phase, with few studies addressing treatment planning and implementation. Because the number of AI-related studies in removable prosthodontics is limited, more models targeting different prosthodontic disciplines are required.

Robot-assisted surgery for dental implant placement: A narrative review

OBJECTIVE

To determine the current status and accuracy of robotic computer-assisted implant surgery (CAIS) applications by examining the associated clinical and experimental outcomes.

DATA AND SOURCES

PubMed, Medline, and Cochrane Library databases were searched for relevant studies published between January 2000 and November 2023, and focusing on robotic CAIS in dental implant surgery. All search results were then manually reviewed to identify only the pertinent articles. Only in vitro and clinical studies were included in this narrative review, with implant placement accuracy considered the main outcome.

RESULT

Based on our inclusion and exclusion criteria, we included 21 studies (with 1085 implant sites); of them, 8 were clinical studies, 12 were in vitro studies, and 1 included both an in vitro study and a case series. The ranges of the mean implant shoulder, apical, and angular deviations were respectively 0.43-1.04 mm, 0.53-1.06 mm, and 0.77°-3.77° in the clinical studies and 0.23-1.04 mm, 0.24-2.13 mm, and 0.43°-3.78° in the in vitro studies, respectively.

CONCLUSION

The accuracy of robotic CAIS in dental implant procedures appears to be within the clinically acceptable ranges. However, further relevant clinical trials validating the existing evidence are needed.

CLINICAL SIGNIFICANCE

Robotic CAIS can achieve clinically acceptable implant placement accuracy. This innovative technology may improve the precision and success rates of dental implant procedures, with benefit for surgeons and patients.

Robotics in Dentistry: A Narrative Review

Background: Robotics is progressing rapidly. The aim of this study was to provide a comprehensive overview of the basic and applied research status of robotics in dentistry and discusses its development and application prospects in several major professional fields of dentistry. Methods: A literature search was conducted on databases: MEDLINE, IEEE and Cochrane Library, using MeSH terms: [“robotics” and “dentistry”]. Result: Forty-nine articles were eventually selected according to certain inclusion criteria. There were 12 studies on prosthodontics, reaching 24%; 11 studies were on dental implantology, accounting for 23%. Scholars from China published the most articles, followed by Japan and the United States. The number of articles published between 2011 and 2015 was the largest. Conclusions: With the advancement of science and technology, the applications of robots in dental medicine has promoted the development of intelligent, precise, and minimally invasive dental treatments. Currently, robots are used in basic and applied research in various specialized fields of dentistry. Automatic tooth-crown-preparation robots, tooth-arrangement robots, drilling robots, and orthodontic archwire-bending robots that meet clinical requirements have been developed. We believe that in the near future, robots will change the existing dental treatment model and guide new directions for further development.

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

OBJECTIVES

To 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).

METHODS

Forty 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.

RESULTS

The 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).

CONCLUSIONS

The 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.

Robotic and Microrobotic Tools for Dental Therapy

Robotic and microrobotic tools such as dental operating microscopes and dental endoscopes are being used extensively in dental therapy, which have a significant impact on dental therapy and education. Herein, this paper reviews the state of the art of robotic and microrobotic tools for dental therapy. This article starts with a brief introduction of current robotic and microrobotic tools for dental therapy and then displays their applications in various dental problems; strengths and weaknesses are also surveyed. Lastly, the conclusion and outlook are discussed, referring to the emerging dental clinic problems and demands. This review is expected to provide guidelines for the therapeutic application of robotic and microrobotic tools and to promote the development of robots in dentistry.

Three-dimensional digital evaluation of thickness accuracy of mock-ups fabricated by silicone matrices: An in vitro study

PURPOSE

Although mock-ups have been widely used in dental esthetic rehabilitation, their accuracy has not been quantitatively evaluated, and the methods of fabricating mock-ups are various. This in vitro study investigated the thickness accuracy of mock-ups fabricated with different silicone matrices.

METHODS

Mock-ups of maxillary anterior teeth were respectively fabricated by 72 silicone matrices that were equally divided into four groups (n=18 for each group) according to two variables of the silicone matrices: labial margin position (equigingival or cover labial gingiva for 1-2 mm) and palatal notches (with or without notches on the palatal side of silicone matrices). The thickness accuracy of the mock-ups was analyzed using 3D scanning and 3D deviation analysis techniques compared with diagnostic waxing. The thickness change ratios of the mock-ups were compared using a two-way analysis of variance (ANOVA). One-way ANOVA and Kruskal-Wallis tests were used to compare differences in thickness change ratios between different teeth in each group.

RESULTS

The thickness accuracy of the mock-ups was significantly affected by the labial margin position and the palatal notches of the silicone matrices, respectively, in the labial area and the incisal area. The most accurate mock-ups were made using silicone matrices with equigingival labial margins and palatal notches. The thickness accuracy of the mock-ups was also inconsistent on different teeth.

CONCLUSIONS

The mock-ups fabricated by silicone matrices were thicker than the diagnostic waxing. The application of silicone matrices to equigingival labial margins and palatal notches was beneficial to the thickness accuracy of mock-ups.

A Novel Method for Adjusting the Taper and Adaption of Automatic Tooth Preparations with a High-Power Femtosecond Laser

This study explored the effect of the light-off delay setting in a robotically controlled femtosecond laser on the taper and adaption of resin tooth preparations. Thirty resin teeth (divided into six equal groups) were studied under different light-off delay conditions. Tapers from six vertical sections of the teeth were measured and compared among the light-off delay groups. The mean taper decreased from 39.268° ± 4.530° to 25.393° ± 5.496° as the light-off delay increased (p < 0.05). The average distance between the occlusal surfaces of the scanned data and the predesigned preparation data decreased from 0.089 ± 0.005 to 0.013 ± 0.030 μm as the light-off delay increased (p < 0.05). The light-off delay of the femtosecond laser is correlated with the taper and adaption of automatic tooth preparations; this setting needs to be considered during automatic tooth preparation.

Robot technology in dentistry, part one of a systematic review: literature characteristics

OBJECTIVES

To provide dental practitioners and researchers with a comprehensive and transparent evidence-based overview of the characteristics of literature regarding initiatives of robot technology in dentistry.

DATA

All articles in which robot technology in dentistry is described, except for non-scientific articles and articles containing secondary data (reviews). Amongst others, the following data were extracted: type of study, level of technological readiness, authors' professional background and the subject of interaction with the robot.

SOURCES

Bibliographic databases PubMed, Embase, and Scopus were surveyed. A reference search was conducted. The search timeline was between January 1985 and October 2020.

STUDY SELECTION

A total of 911 articles were screened on title and abstract of which 161 deemed eligible for inclusion. Another 71 articles were excluded mainly because of unavailability of full texts or the sole use of secondary data (reviews). Four articles were included after hand searching the reference lists. In total, 94 articles were included for analysis.

CONCLUSIONS

Since 2013 an average of six articles per year concern robot initiatives in dentistry, mostly originating from East Asia (57%). The vast majority of research was categorized as either basic theoretical or basic applied research (80%). Technology readiness levels did not reach higher than three (proof of concept) in 55% of all articles. In 84%, the first author of the included articles had a technical background and in 36%, none of the authors had a dental or medical background. The overall quality of literature, especially in terms of clinical validation, should be considered as low.

Robot technology in dentistry, part two of a systematic review: an overview of initiatives

OBJECTIVES

To provide dental practitioners and researchers with a comprehensive and transparent evidence-based overview of physical robot initiatives in all fields of dentistry.

DATA

Articles published since 1985 concerning primary data on physical robot technology in dentistry were selected. Characteristics of the papers were extracted such as the respective field of dentistry, year of publication as well as a description of its usage.

SOURCES

Bibliographic databases PubMed, Embase, and Scopus were searched. A hand search through reference lists of all included articles was performed.

STUDY SELECTION

The search timeline was between January 1985 and October 2020. All types of scientific literature in all languages were included concerning fields of dentistry ranging from student training to implantology. Robot technology solely for the purpose of research and maxillofacial surgery were excluded. In total, 94 articles were included in this systematic review.

CONCLUSIONS

This study provides a systematic overview of initiatives using robot technology in dentistry since its very beginning. While there were many interesting robot initiatives reported, the overall quality of the literature, in terms of clinical validation, is low. Scientific evidence regarding the benefits, results and cost-efficiency of commercially available robotic solutions in dentistry is lacking. The rise in availability of open source control systems, compliant robot systems and the design of dentistry-specific robot technology might facilitate the process of technological development in the near future. The authors are confident that robotics will provide useful solutions in the future but, strongly, encourage an evidence-based approach when adapting to new (robot) technology.

Dental Robotics: A Disruptive Technology

Robotics is a disruptive technology that will change diagnostics and treatment protocols in dental medicine. Robots can perform repeated workflows for an indefinite length of time while enhancing the overall quality and quantity of patient care. Early robots required a human operator, but robotic systems have advanced significantly over the past decade, and the latest medical robots can perform patient intervention or remote monitoring autonomously. However, little research data on the therapeutic reliability and precision of autonomous robots are available. The present paper reviews the promise and practice of robots in dentistry by evaluating published work on commercial robot systems in dental implantology, oral and maxillofacial surgery, prosthetic and restorative dentistry, endodontics, orthodontics, oral radiology as well as dental education. In conclusion, this review critically addresses the current limitations of dental robotics and anticipates the potential future impact on oral healthcare and the dental profession.

[Precise tooth preparation technique guided by 3D printing guide plate with quantitative hole]

The minimum amount of tooth preparation that can be fully controlled is crucial in achieving long-term, stable, and effective aesthetic restoration, which is also a major difficulty in aesthetic restoration. The tooth preparation can be imple-mented efficiently and accurately through digital technology based on the fixed-deep hole guiding technology. Prior the actual tooth preparation, the technology first designs the virtual contour, layering, and virtual occlusion of the prosthesis on the computer. Then, virtual tooth preparation is carried out by cutting back according to the virtual prosthesis. Next, the virtual drilling operation plan is designed according to the shape of the virtual tooth preparation and the contour of the abutment tooth. Finally, the tooth preparation guide plate is designed and printed in 3D. It realizes the whole process of quantitative and precise guidance of dental preparation, visualizes the restoration space, reduces the clinical operation time, and guarantees the quality of dental preparation. It also promotes the improvement of the teaching quality of digital practical exercises.

Dentronics: Towards robotics and artificial intelligence in dentistry

OBJECTIVES

This paper provides an overview of existing applications and concepts of robotic systems and artificial intelligence in dentistry. This review aims to provide the community with novel inputs and argues for an increased utilization of these recent technological developments, referred to as Dentronics, in order to advance dentistry.

METHODS

First, background on developments in robotics, artificial intelligence (AI) and machine learning (ML) are reviewed that may enable novel assistive applications in dentistry (Sec A). Second, a systematic technology review that evaluates existing state-of-the-art applications in AI, ML and robotics in the context of dentistry is presented (Sec B).

RESULTS

A systematic literature research in pubmed yielded in a total of 558 results. 41 studies related to ML, 53 studies related to AI and 49 original research papers on robotics application in dentistry were included. ML and AI have been applied in dental research to analyze large amounts of data to eventually support dental decision making, diagnosis, prognosis and treatment planning with the help of data-driven analysis algorithms based on machine learning. So far, only few robotic applications have made it to reality, mostly restricted to pilot use cases.

SIGNIFICANCE

The authors believe that dentistry can greatly benefit from the current rise of digital human-centered automation and be transformed towards a new robotic, ML and AI-enabled era. In the future, Dentronics will enhance reliability, reproducibility, accuracy and efficiency in dentistry through the democratized use of modern dental technologies, such as medical robot systems and specialized artificial intelligence. Dentronics will increase our understanding of disease pathogenesis, improve risk-assessment-strategies, diagnosis, disease prediction and finally lead to better treatment outcomes.

[Recent progress of robots in stomatology]

With the development of industrial robot technology, robotics has entered the medical field, and the research and development of new robots for many medical applications have become a significant research direction in global robotics. Robots are widely used in various aspects of dentistry, such as prosthodontics, orthodontics, implants, endodontics, and oral surgery. This article mainly introduces the application of robots in stomatology from the above five aspects.

Osteoblast differentiation of bone marrow stromal cells by femtosecond laser bone ablation

This study examines the osteogenic effect of femtosecond laser bone ablation on bone mesenchymal stromal cells (BMSCs). Three-week old Sprague-Dawley (SD) rats were selected for experiments. Right tibias were ablated by a 10-W femtosecond laser (treated group), whereas left tibias were not subjected to laser ablation (control group). After ablation, BMSCs of both tibias were cultured and purified separately. Cell proliferation was then analyzed, as well as the expressions of RNA and several proteins (alkaline phosphatase (ALP), runt-related transcription factor 2 (RUNX2) and osteocalcin (OCN)). The results suggest that femtosecond laser ablation promotes the differentiation of BMSCs and up-regulates the expression of ALP, RUNX2, and OCN, without affecting BMSC proliferation.

Advanced laser scanning for highly-efficient ablation and ultrafast surface structuring: experiment and model

Ultra-short laser pulses are frequently used for material removal (ablation) in science, technology and medicine. However, the laser energy is often used inefficiently, thus, leading to low ablation rates. For the efficient ablation of a rectangular shaped cavity, the numerous process parameters such as scanning speed, distance between scanned lines, and spot size on the sample, have to be optimized. Therefore, finding the optimal set of process parameters is always a time-demanding and challenging task. Clear theoretical understanding of the influence of the process parameters on the material removal rate can improve the efficiency of laser energy utilization and enhance the ablation rate. In this work, a new model of rectangular cavity ablation is introduced. The model takes into account the decrease in ablation threshold, as well as saturation of the ablation depth with increasing number of pulses per spot. Scanning electron microscopy and the stylus profilometry were employed to characterize the ablated depth and evaluate the material removal rate. The numerical modelling showed a good agreement with the experimental results. High speed mimicking of bio-inspired functional surfaces by laser irradiation has been demonstrated.

Regulation and Measurement of the Heat Generated by Automatic Tooth Preparation in a Confined Space

OBJECTIVE

The aim of this study was to assess and regulate heat generation in the dental pulp cavity and circumambient temperature around a tooth during laser ablation with a femtosecond laser in a confined space.

BACKGROUND DATA

The automatic tooth preparing technique is one of the traditional oral clinical technology innovations. In this technique, a robot controlled an ultrashort pulse laser to automatically complete the three-dimensional teeth preparing in a confined space. The temperature control is the main measure for protecting the tooth nerve.

METHODS

Ten tooth specimens were irradiated with a femtosecond laser controlled by a robot in a confined space to generate 10 teeth preparation. During the process, four thermocouple sensors were used to record the pulp cavity and circumambient environment temperatures with or without air cooling. A statistical analysis of the temperatures was performed between the conditions with and without air cooling (p < 0.05).

RESULTS

The recordings showed that the temperature with air cooling was lower than that without air cooling and that the heat generated in the pulp cavity was lower than the threshold for dental pulp damage.

CONCLUSIONS

These results indicate that femtosecond laser ablation with air cooling might be an appropriate method for automatic tooth preparing.