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.

Investigation of variation factors in EMG measurement of swallowing: instruction can improve EMG reproducibility.

Variability in swallowing electromyography (EMG) has been reported to occur due to individual differences, even in studies with appropriate control of factors affecting EMG such as food type, properties, and posture. The increased variability broadens the confidence intervals of measures obtained from EMG, such as time and amplitude, and makes it difficult to detect differences in muscle activity. This makes it impossible to detect slight changes in swallowing function at an early stage, which is required for clinical examination. In this study, we focused on the tipper type and dipper type of oral swallows, which differ in the timing of muscle activity. The frequency of occurrence of both types varies between participants, and both types could occur in the same participant. In this study, we measured swallowing EMG wherein participants were instructed to swallow with a tipper and a dipper. The results showed that there was a significant difference in the between-participant duration between these two types of swallows. Within-participant variability was significantly lower in the tipper-dipper instruction condition compared to the baseline condition, which assumed a mixture of tipper-dipper swallowing. These results demonstrate that instructions on swallowing method are effective in improving the reproducibility of EMG.

Evaluation of musculoskeletal workload of manual operating tasks using a hydraulic jack based on ergonomic postural analysis and electromyography: A case study of non-professional young male users.

BACKGROUND: Manual operations of the hydraulic jack device can become ergonomic stressors for the musculoskeletal system because of the required operational forces, muscle activities, or working postures. However, the usability of the hydraulic jack has not been fully explored for non-professional personnel. OBJECTIVES: To evaluate the musculoskeletal loads during manual operations of a hydraulic jack based on the ergonomic postural analysis and electromyographyMETHODS:Nine men operated the lever of a hydraulic jack with three positions: parallel to and near (P-N), parallel to and far from (P-F), and orthogonal to the jack lever (O). Postural loads were evaluated by Loading on the Upper Body Assessment (LUBA), an ergonomic observational method, and were classified into action categories. The surface electromyogram of eight muscles and the subjective sense of burden were also measured. RESULTS: The initial force for lever pushing reached 40-80 N and exceeded the recommended forces for the unusual postures. The overall assessment of LUBA showed that 31% of working postures observed in O position require immediate consideration and corrective action and the maximum holding time estimated was < 1 minute. The postural load increased due to the shoulder joint abduction in the P-F and O positions and due to the trunk rotation in O position. CONCLUSIONS: The results suggest that operating the hydraulic jack cause considerable postural loads and manual forces insufficient for several minutes of manual task. Therefore, improving working methods and tool designs are needed to improve usability and decrease the risk of musculoskeletal disorders during jack operations.

Effects of age and gender on swallowing activity assessed by electromyography and laryngeal elevation.

BACKGROUND: Quantitative assessment of swallowing function is necessary to prevent swallowing impairment due to ageing. Though surface electromyography (EMG) has been widely used to measure swallowing activity, the relationship between EMG results and swallowing function is unclear. OBJECTIVE: This study examined the relationship between the temporal characteristics of muscle activity and laryngeal elevation (LE) during swallowing. METHODS: This study analysed 60 healthy volunteers in two age groups (young, between 20 and 38 years; old, between 65 and 75 years), each containing the same number of male and female participants. Surface EMG signals were recorded from the suprahyoid and infrahyoid muscle groups (SH-EMG and IH-EMG, respectively). LE was measured using an array of pressure sensors. The participants swallowed 3 mL of water under three swallowing speed conditions: fast, normal and slow swallowing. The EMG duration, EMG time intervals before and after the onset of LE (pre-LE and post-LE intervals, respectively), and the LE velocity were analysed. RESULTS: Both EMG duration and the post-LE interval of IH-EMG were significantly longer in the older group. As for the gender effect, the pre-LE interval of SH-EMG was significantly longer and the LE velocity was significantly higher in men than in women. Furthermore, there was a negative correlation between pre-LE interval and LE velocity in the fast swallowing condition. CONCLUSION: Though ageing slightly prolonged the muscle activity time, gender influenced swallowing activity in a more complex manner. Therefore, it is important to take gender into account when examining swallowing function with increasing age.

Buckling Force Variability of Semmes⁻Weinstein Monofilaments in Successive Use Determined by Manual and Automated Operation.

(1) Objective: This study was conducted with the objective of characterizing the variability of a force on a simulated skin surface using the Semmes⁻Weinstein monofilament test (SWMT). (2) Research Design and Methods: Two distinct experiments were performed to determine the effects of human hand motion variability on the monofilament buckling force, and to determine the monofilament's mechanical properties using a positioning stage. (3) Results: In manual operation (by human hand motion), the buckling force over the ten compressions decreased by over 10%, and the human hand motion variations during the SWMT may have impacted the buckling force. When the SWMT was performed under manual control, the buckling force was closely correlated with the number of compressions. In automated operation (by positioning stage), the buckling force was affected not only by the number of compressions but also by both the velocity and the contact angle between the monofilament and the skin surface. (4) Conclusions: The buckling force decreased in ten successive compressions, independent of the hand motion. Hence, medical staff need to consider not only the operator's hand motion but also the effect of repeated trials.

Application of metal hydride paper to simple pressure generator for use in soft actuator systems.

Metal hydride (MH) actuators have a simple structure and a number of features that make them attractive for use in rehabilitation engineering and assistive technology. The MH actuator provides a high power-to-weight ratio, high-strain actuation, human-compatible softness, and noiseless operation, while being environmentally benign. On the other hand, there remain technical challenges to be overcome to improve the MH actuator regarding its speed of operation and energy efficiency, given the low heat conductivity of the MH powder that is used as the pressure generator for soft actuation. To overcome the issues of low heat conductivity and the handling of MH powder, we developed an MH paper, which is a special paper incorporating MH powder and carbon fiber, for use as a new pressure-generating element for a soft MH actuator system. In addition, the basic properties and structure of the proposed MH paper were investigated through scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and several thermodynamic experiments. The results of these experiments showed that the hydrogen absorption and desorption rates of the MH paper were significantly higher than those of the MH powder around room temperature.

Evaluation of the variation in sensory test results using Semmes-Weinstein monofilaments.

The purpose of this study is to examine the variability in sensory test of tactile results using Semmes-Weinstein monofilament (SWM). At present, several methods for measuring the tactile sensitivity are clinically used in diabetic peripheral neuropathy screening. One of these methods is a touch test that uses a device with nylon SWMs, i.e., SWMs embedded in a plastic handle. A small pushing force is applied at the handle to bow the filaments. Because of its ease and simplicity, the SWM test is conducted at the patient's bedside in a hospital. However, previous studies have reported some problems with this test. Studies have shown variations in the measured data, and it is uncertain whether these variations are caused by mechanical properties of the nylon fiber or by the motion of the operator's hands. We carried out two experiments to examine the effect of (1) the variability caused by the human operator conducting the SWM test on the test results and (2) the number of compressions of the SWM on the test results. In experiment 1, we measured the velocity of the operator's hand motion and the buckling force of the SWMs. The results showed variability in the hand motion of the operator conducting the SWM tests. In experiment 2, we measured the buckling force of the SWMs under a controlled velocity. We compared the buckling force of the SWMs through a number of trials. These results showed that the buckling force gradually decreases as the number of test cycles increase. In conclusion, we find that the accuracy of the SWM tests is a factor of the number of test cycles. Additionally, manual training for standardizing skills of medical staff members needs to be developed. Furthermore, the characteristics of the SWMs deteriorated over time. In future work, we aimto find a solution to minimize the variability in the SWM test results and develop a new testing system that uses tactile sensibility for diabetic peripheral neuropathy screening.

A pilot study of a plantar sensory evaluation system for early screening of diabetic neuropathy in a weight-bearing position.

The purpose of this study is to develop smart equipment to quantify plantar tactile sensibility for the early diagnosis and tracking of peripheral neuropathy caused by diabetes mellitus. In this paper, we offer a new testing system that is composed of a plantar tactile stimulation platform with a small moving contactor to stretch the skin tangentially, a response switch for each tactile stimulus, a motor control box, and a personal computer (PC) for psychophysical data processing. This quantitative sensory testing system has detailed measurements available and is easy to use compared with the conventional testing devices, such as von Frey monofilaments, pin-prick testing devices, and current perception threshold testers. When using our testing system in a weight-bearing position, we observed that the plantar tactile thresholds for the tangential stretching stimulus on the plantar surface of the foot ranged from approximately 10 um to 30 um for healthy subjects. However, the threshold for a subject with diabetes was nearly three times higher than that for healthy subjects. The significant difference between these values suggests that the plantar sensory evaluation system using the lateral skin stretch stimulation can be used for early diagnosis, for the accurate staging of diabetic neuropathy, and for evaluating its progression noninvasively in a clinic and at home.