ABSTRACT
The need to increase the Vertical Dimension of Occlusion (VDO) to restore lost dental function or optimise specific dental treatments is a common occurrence in daily dental practice. The common belief that the Vertical Dimension at Rest (VDR) is fixed hinders the development of restorations with a VDO that encroaches on or surpasses the interocclusal rest space (IRS), thereby preventing potential tissue damage to the masticatory apparatus. Recent studies have shown that the mandible rest position falls within a range termed as the "comfort zone". The range of this zone may vary from one person to another and within the same person over time due to factors such as age or health status. In this review, we have concluded that a permanent increase in the VDO, once indicated, is a safe procedure for dentulous patients. However, it is important to minimise the extent of the increase to simplify the prosthodontics treatment process. An inter-incisal increase exceeding 5 mm is seldom needed. Moreover, it is important to consider the functional, aesthetic, and biological elements associated with VDO. The biological and functional environment closely related to the VDO had great adaptive capacities, which have for a historically been underestimated. Patient adaptation has been observed in dentate patients, edentulous patients, and even cases involving implant-supported prostheses. Muscle relaxation and changes in muscle length are likely the primary adaptation mechanisms, rather than the restoration of the original VDO through dentoalveolar maturation. Intervention with a fixed restoration is more predictable and results in a higher and more rapid level of adaptation. Finally, the increase should include the entire arch to prevent relapse of the VDO to its previous value, and changes in VDO should be assessed by utilising temporary diagnostic restorations for a period before implementing definitive prostheses, in order to evaluate the adaptive muscle response.
ABSTRACT
The recording of the maxillo-mandibular relationship (MMR) is an essential and unavoidable step that occurs at different stages of treatment during a prosthetic rehabilitation. Tissue duality is a major problem in metal partial dentures (MPD), especially in complete and large edentulisms, and is responsible for occlusal inaccuracies resulting in restorations that are not integrated with the patient's manducatory system. In order to perform this step, the practitioner must choose the right material, make the appropriate support, and adopt a reliable and reproducible technique that is adapted to the clinical situation and the prosthetic step. The objective of this work is to suggest a simple and codified approach, which guarantees a reliable recording of the maxillo-mandibular relationship, adapted to the particularities of the supporting structures and taking into consideration the clinical sequence for an optimal occlusal-functional integration of the future metallic partial denture.
Subject(s)
Denture, Partial, Removable , Denture DesignABSTRACT
Background: The main objective of this systematic review was to evaluate the effect of coating with titanium dioxide nanoparticles (TiO2 nanoparticle) on the surface condition of removable acrylic resin prosthetic base materials. Methods: Our review is registered in the PROSPERO database under the identification code CRD42023397170. Electronic database searches of PubMed, Scopus and Science Direct including studies from January 2009 to January 2023 were conducted and supplemented with manual searches. Research questions were generated in accordance with the PICO strategy. The modified Consolidated Standards of Reporting Trials (CONSORT) checklist was used to evaluate the quality of the selected studies. Results: Since the included studies were variable in design, a meta-analysis was not performed. The electronic searches retrieved 29 references that met the eligibility criteria, among which 5 studies matched the inclusion criteria for this review. Significant differences were detected between the TiO2 NP-coated and uncoated groups. The available data indicate that TiO2 NP coating elicits antimicrobial activity and improves the wear resistance of polymethylmethacrylate (PMMA) surfaces. Moreover, the nanoparticles provide high levels of glossiness and decelerate the process of color change of heat-cured acrylic resin, thus increasing the lifespan of dentures. Conclusion: The collective results clearly indicate that TiO2 nanoparticle coating induces alterations in the surface properties of pure PMMA, enhancing the mechanical, physical and biological characteristics of the denture base material. Further studies are essential to identify the optimal thickness of coating and concentrations of nanoparticles for clinical applications.
