Development of a Novel Medical Device for Mucositis and Peri-Implantitis Treatment.

In spite of all the developments in dental implantology techniques, peri-implant diseases are frequent (prevalence up to 80% and 56% of subjects for mucositis and peri-implantitis, respectively) and there is an urgency for an effective treatment strategy. This paper presents an innovative electromedical device for the electromagnetic treatment of mucositis and peri-implantitis diseases. This device is also equipped with a measurement part for bioimpedance, which reflects the health conditions of a tissue, thus allowing clinicians to objectively detect impaired areas and to monitor the severity of the disease, evaluate the treatment efficacy, and adjust it accordingly. The design of the device was realized considering literature data, clinical evidence, numerical simulation results, and electromagnetic compatibility (EMC) pre-compliance tests, involving both clinicians and engineers, to better understand all the needs and translate them into design requirements. The reported system is being tested in more than 50 dental offices since 2019, providing efficient treatments for mucositis and peri-implantitis, with success rates of approximately 98% and 80%, respectively.

Bioimpedancemetry for the assessment of periodontal tissue inflammation: a numerical feasibility study.

In dentistry possible inflammatory episodes of oral cavity can be very frequent (periodontitis, mucositis, peri-implantitis) and they can have serious consequences. Indeed, peri-implantitis is still the principal cause of implant failure. Impedance values of biological tissues are related to the physiological/pathological state of the tissue itself. In fact, an inflamed site exhibits an impedance value lower than that of the corresponding healthy tissue. Based on these observations, the aim of this work is to determine if impedancemetric measurements are able to provide information about the inflammatory state of tissues. A numerical 3D model has been realized to simulate the measurement conditions present in the event of inflammation around a dental implant. The aim is to understand if it is possible to determine the presence of an inflamed tissue and to locate its site, so that the treatment could be specifically focused in that specific area. A simplified geometry reproducing the implant has been realized in order to validate the numerical model by means of experimental measurements. The obtained results are satisfactorily accurate, so the model can be considered reliable. Therefore, multiple simulations have been run on the original model to carry out a parametric study in terms of different conductivity values, different volumes of inflamed tissues and different measurement frequencies. The advantages and limits of such a method have been shown to properly define the main constraints for the system design.

Optimization of the excitation and measurement procedures in nondestructive testing using shearography.

This paper deals with the development of optimal procedures for nondestructive testing (NDT) inspections using shearography. In the new proposed method a parameter is adopted, the contrast-to-noise ratio (CNR), which allows the quantification of the contrast of the defect to the background in the image. During the calibration of the technique, on samples with known defects, the CNR also takes into account the size and location of the identified defects, compared to those expected. The optimal measurement and loading conditions (e.g., excitation temperature level, time between image acquisitions) are determined by experimental parametric analyses aimed at maximizing the CNR on specimens with known defects. In the present work the developed methodology is described and applied to the definition of best practices for the NDT analysis of aeronautical sandwich composites structures (used in the production of helicopters) by shearography inspection with thermal excitation. In this case the attention is focused on optimizing the thermal loading procedures, but it can be clearly extended to other types of excitation methods.

Stress distribution in fiber-reinforced composite inlay fixed partial dentures.

STATEMENT OF PROBLEM: Fiber-reinforced composite inlay fixed partial dentures (FRCIFPDs) may be a reliable prosthetic solution. Clinical procedures involved in their fabrication have been defined, but little is known about their mechanical behavior. PURPOSE: This in vitro study used the finite element (FE) method to investigate 3-dimensional (3-D) stress and strain distribution produced in a 3-unit FRCIFPD. MATERIAL AND METHODS: A 3-D FE model (227,768 3-D tetrahedral elements) of a 3-unit FRCIFPD cemented onto box-shaped prepared teeth was developed. Stress and strain distribution generated by a maximum load of 196 N applied vertically or laterally to the FRCIFPD centrally, on an area of 4 +/- 0.1 mm 2 , was analyzed. The specimen used to acquire the geometry of the model was also used for mechanical compressive tests, with vertical and lateral loads, to validate the numerical model. RESULTS: The peak values of stress, calculated on the outer and inner surfaces of the FRCIFPD, were localized in the connector areas. When a vertical load was applied, stress on the prepared teeth was concentrated at the cervical margin of the abutment preparation. CONCLUSION: Within the limitations of this in vitro study, the results suggest that within the FRCIFPD, stress concentrates at the connector areas, and that in the prepared teeth, peak stress is at the cervical margin of the box of the preparation.