Oral Surgery and Osteoradionecrosis in Patients Undergoing Head and Neck Radiation Therapy: An Update of the Current Literature.

Osteoradionecrosis (ORN) is a serious long-term complication of head and neck radiotherapy (RT), which is often triggered by dental extractions. It results from avascular aseptic necrosis due to irradiated bone damage. ORN is challenging to treat and can lead to severe complications. Furthermore, ORN causes pain and distress, significantly reducing the patient's quality of life. There is currently no established preventive strategy. This narrative review aims to provide an update for the clinicians on the risk of ORN associated with oral surgery in head and neck RT patients, with a focus on the timing suitable for the oral surgery and possible ORN preventive treatments. An electronic search of articles was performed by consulting the PubMed database. Intervention and observational studies were included. A multidisciplinary approach to the patient is highly recommended to mitigate the risk of RT complications. A dental visit before commencing RT is highly advised to minimize the need for future dental extractions after irradiation, and thus the risk of ORN. Post-RT preventive strategies, in case of dento-alveolar surgery, have been proposed and include antibiotics, hyperbaric oxygen (HBO), and the combined use of pentoxifylline and tocopherol ("PENTO protocol"), but currently there is a lack of established standards of care. Some limitations in the use of HBO involve the low availability of HBO facilities, its high costs, and specific clinical contraindications; the PENTO protocol, on the other hand, although promising, lacks clinical trials to support its efficacy. Due to the enduring risk of ORN, removable prostheses are preferable to dental implants in these patients, as there is no consensus on the appropriate timing for their safe placement. Overall, established standards of care and high-quality evidence are lacking concerning both preventive strategies for ORN as well as the timing of the dental surgery. There is an urgent need to improve research for more efficacious clinical decision making.

Novel 3D printing method to reinforce implant-supported denture fiberglass as material for implant prosthesis: A pilot study.

OBJECTIVES: Despite a large amount of materials and methods to make an implant-supported denture, nowadays there is no gold standard. Every solution has pros and cons that guide the clinician and the technician to choose the best solution for a single case. The aim of this study was to evaluate the mechanical characteristics of the fiber-reinforced composite superstructure made by using a novel three-dimensional (3D) printing technology able to create a reinforcing structure patient-specific, more reliable, structurally optimized, and faster than conventional methods. MATERIALS AND METHODS: To evaluate mechanical performances of 3D-printed fiberglass, mechanical characterization of 3D-printed material was performed. Before proceeding with the realization of the final prosthesis, five specimens were created on which the tensile test and volumetric fiber content measurement were performed. Then denture reinforcement 3D printing process began. Initially, the robot prints layers of fiber. Finally, the obtained 3D-printed reinforcement structure was finalized in the lab. RESULTS: The prosthesis obtained through this process was lighter than a traditional prosthesis, there was a greater chemical adhesion between resin and 3D-printed reinforcement structure and a better result was obtained from an esthetic point of view. CONCLUSIONS: The outcomes we obtained endorse its performance both mechanical and esthetic. The entire process is automatic and does not require human operation thanks to specific software programming.

Topological optimization of implant-prosthetic structures.

AIM: The aim of the present study was to verify the possibility of obtaining an optimized prosthetic substructure using generic software, respecting the distribution loads and forces involved. What is considered to be original and innovative in this study is the possibility of designing the prosthetic substructure on the basis of the individual patient's chewing biomechanics, with the purpose of obtaining an even greater efficiency than a prosthesis designed according to a traditional method. MATERIALS AND METHODS: The starting standard triangulation language (STL) file was processed with Rhinoceros software and the tOpos plugin. It was decided to submit the entire prosthetic solution, intended as total volume, to structural analysis and topological optimization because the entire prosthesis is subjected to load during the chewing act. The software program was provided with information on the material, modulus, and direction of the applied forces. The objective was to optimize stiffness by maximizing volume. RESULTS: The volume of the final structure was 2% compared with the starting model and was a completely different design compared with the traditional model. This new design was characterized by trabeculations that reflect the normal bone architecture. The material was distributed on the basis of the load points as well as the direction and modulus of the applied force. CONCLUSIONS: After assessing the applicability of the proposed workflow and the results obtained thus far, the most important clinical implication is represented by the greater efficiency and the same resistance of the prosthesis obtained with topological optimization compared with that obtained with the traditional method.

Characterization of induced mucosal connective tissue separation--a comparison of six different techniques.

BACKGROUND: Artificial separation of oral mucosa into epithelium and connective tissue represents the first step in investigating both the basement membrane zone and its two components (epithelium and connective tissue) separately. It is a useful tool in analysing the possible role of hepatitis C virus in the pathogenesis of oral lichen planus (OLP). The aim of the present study was to test different methods to separate the epithelium from the connective tissue of oral mucosa affected by OLP as a preliminary step for further immunohistochemical or molecular investigations. PATIENTS AND METHODS: Fourteen tissue biopsies of the oral mucosa of clinically and histopathologically confirmed OLP lesions underwent epithelial connective separation (ECS) using six different reagents. RESULTS AND CONCLUSIONS: Among the separation methods tested, CaCl2 1 M at 37 degrees C for 30 min, NaCl 1 M at 4 degrees C for 26 h and elastase at 4 degrees C for 22 h allowed good ECS without structural alteration or tissue loss. The present study provides useful information regarding techniques to separate the epithelium from the connective tissue as a preliminary step to investigate oral mucosa affected by OLP from an immunohistochemical or molecular viewpoint.