The Influence of Printing Layer Thickness and Orientation on the Mechanical Properties of DLP 3D-Printed Dental Resin.

Technological advances are closely related to the development of new materials and their processing and manufacturing technologies. In the dental field, the high complexity of the geometrical designs of crowns, bridges and other applications of digital light processing 3D-printable biocompatible resins is the reason for the need for a deep understanding of the mechanical proprieties and behavior of these materials. The aim of the present study is to assess the influence of printing layer direction and thickness on the tensile and compression proprieties of a DLP 3D-printable dental resin. Using the NextDent C&B Micro-Filled Hybrid (MFH), 36 specimens (24 for tensile strength testing, 12 for compression testing) were printed at different layer angulations (0°, 45° and 90°) and layer thicknesses (0.1 mm and 0.05 mm). Brittle behavior was observed in all specimens regardless of the direction of printing and layer thickness for the tensile specimens. The highest tensile values were obtained for specimens printed with a layer thickness of 0.05 mm. In conclusion, both printing layer direction and thickness influence mechanical proprieties and can be used to alter the materials' characteristics and make the final printed product more suitable for its intended purposes.

FEM Analysis of Individualized Polymeric 3D Printed Guide for Orthodontic Mini-Implant Insertion as Temporary Crown Support in the Anterior Maxillary Area.

Either due to trauma, extraction or congenital factors, the absence of teeth has aesthetic, functional, financial and psychological consequences. The aim of the current study is to assess an individualized polymeric 3D printed digitally planned surgical guide designed to achieve precision and predictability in non-standard mini-implant orthodontic cases. Twenty-seven patient records with missing anterior teeth were selected from the database of a private clinic in Timisoara, Romania. Based on the analysis of the cases included in the research, a surgical guide for the insertion of mini-implants as provisional crown support was designed. An FEM simulation was performed using the Abaqus numerical analysis software. Finite element simulation revealed the maximum displacements and stresses that occur in the surgical guide. Mini-implant supported provisional crowns can be a simple and low-cost method to increase patient self-esteem and compliance with the orthodontic treatment. Computer aided mechanical simulation is a useful tool in analyzing different polymeric surgical guide designs before being used in clinical situations in order to avoid failure.

Perception and Knowledge of Dental Ergonomics among Romanian Dental Students.

Musculoskeletal disorders (MSDs) are among leading factors for early retirement of dental practitioners while the application of ergonomic principles is often overlooked during dental education. The article aims to assess the need for dental ergonomics modules as an integrated part of the dental school curriculum and to quantify the significance and role of ergonomics in reducing musculoskeletal stress generated while undergoing dental training. The study design consisted of a three-part original close-ended multiple-choice questionnaire carried out among 75 sixth year students from "Victor Babes" University of Medicine and Pharmacy, Timisoara, Romania. Questions focused on the basic knowledge of theoretical ergonomics, the ISO 11226 standard and means of improvement in undergraduate ergonomics training. Most students had an average level of knowledge regarding dental ergonomic principles. Data analysis showed that 62.16% agree that the information received in the second-year dental ergonomics course was helpful in regard to time organization. A high percentage (86%) also understood the correct positioning of the patient while performing dental procedures. Although implementation of ergonomic principles in the early dental training years has a high influence in the prevention of MSDs, students do not fully understand the impact this subject has on their future careers.

The use of baropodometric analysis in musculoskeletal disorders of dentists working in orthostatic posture - a series of 3 cases.

INTRODUCTION: Musculoskeletal disorders (MSDs) caused by incorrect working posture among dentists is a serious issue and one that leads to decreased productivity and quality of life. AIM: The aim of this study was to evaluate the impact of MSDs caused by postural errors in dental healthcare professionals on the body's center of gravity through a new and innovative technique - baropodometry. METHODS: In this study we included 3 oral healthcare specialists with over 20 years experience of practicing in orthostatism, with confirmed work-related MSDs, and performed a baropodometric analysis on them. RESULTS: According to the analysis, all 3 test subjects had alterations of the body's center of gravity, with uneven distribution of pressures on the feet being recorded by the baropodometer. CONCLUSION: In an effort to maintain a good field of view and workplace in orthostatism, the subject is forced to adopt an non-ergonomic position that leads to uneven weight distribution, shifted center of gravity that eventually cause musculoskeletal disorders.