Increasing Vertical Dimension of Occlusion (VDO): Review.

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.

Complete Removable Denture Retained by a Symphyseal Single Implant: A Case Report.

Complete denture is a real challenge for any practitioner. The aim of implantology is to optimize prosthetic balance and ensure that prostheses are perfectly integrated from a bio-functional viewpoint, despite an unfavorable anatomophysiological context. Here, we present a case managed in our department concerning a mandibular complete removable denture retained by a medial symphyseal implant. A 61-year-old fully edentulous mandibular patient with a Kennedy Applegate class I edentulous maxilla in good general health consulted for the renewal of his mandibular complete denture, which was deemed unstable and non-retentive. The exo-oral examination was normal. The mandibular crest was heavily resorbed, especially posteriorly, and covered with slightly inflammatory fibromucosa. The patient refused bone augmentation surgery. We performed a piezographic mandibular prosthesis retained by a single standard implant at the level of the mandibular symphysis. The prosthesis was stable and retentive. Masticatory comfort and efficiency were satisfactory and the psychological integration of the prosthesis was improved. Several studies have shown that a single symphyseal implant is a therapeutic alternative that completes the therapeutic range in specific cases. It should be limited to the mandibular arch in elderly patients with reduced bone volume. Given the lack of randomized controlled trials, routine use of this new approach is not recommended, and further studies are required.

Denture Base Resin Coated with Titanium Dioxide (TiO2): A Systematic Review.

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.

[Maxillomandibular relationship recording in removable partial petal dentures (RPMD)]. / Enregistrement du rapport maxillo-mandibulaire en prothèse amovible partielle métallique (PAPM).

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.

Impression techniques in Removable partial denture: epidemiological study.

INTRODUCTION: Various impression techniques are used in the realization of free-end extension partial denture, one of the imperatives is to respect the compressibility and behavior of the tissue during impression making as well as during function. AIM: To evaluate the knowledge and practices of private practitioners regarding secondary impressions made during the management of terminal edentulism with metallic removable partial denture, and to search for possible correlations between prosthetic complaints and non-compliance with the various final impression standards in terms of materials, equipment and techniques. METHODS: The study involved a sample of dentists practicing in the Rabat-Sale-Kenitra region in the Kingdom of Morocco. The paper questionnaire was filled out in face-to-face interviews or by the dentists themselves. The computerized questionnaire was sent to the dentists by e-mail or via various social network platforms. A descriptive and analytical statistical study was carried out to treat the data. RESULTS: Following the results of the statistical study: (57.6%) used the alginate as a secondary impression material, (66%) used individual trays, 17% used models from primary impressions for direct prosthesis fabrication, (17%) used the cast impression technique in free end mandibular edentulous. (77%) recorded the peripheral joint in Kennedy Applegate class I and II, concerning the complaints; practitioners who worked with more than one impression material or those who use solely the alginate encountered a combination of similar complaints (75%). CONCLUSION: The practices of the dentists differ in terms of materials and techniques used in the management of edentulous terminals by removable partial denture (RPD). The complaints expressed by patients were independent of the method used in the secondary impression. The results of our survey concur with the fact that until today there is no consensus to demonstrate that a technique, or a material can be more reliable for the stability and the success of the RPD.

Prosthetic management of gag reflex: Case report.

A relatively common oral health problem, gag reflex is a clinical challenge during dentures fabrication. In the current literature several techniques have been described regarding this clinical condition. The latter use either psychological, pharmacological and prosthetic therapies to treat these patients. The purpose of this case report is to highlight an original prosthetic strategy which consists on a progressive lengthening of the maxillary complete prosthesis allowing a patient with acute gag reflex to adapt to the denture palatal extension.

Prosthetic and surgical management of a sizeable epulis fissuratum: a case report.

This case report describes the management of a large-sized Epulis Fissuratum (EF) in a 70-year-old female patient using an original prosthetic technique. It consists of a combination of a tissue conditioning and a resection surgery. The patient´s main concern was a mucogingival tissue growth located on the left mandibular area. The interesting clinical findings deriving from this technique are: tissue conditioning is an important phase prior to the surgical resection of a large EF and occlusal functions can be maintained during the procedures with patient´s corrected dentures. After clinical, radiological and pathological examinations, the diagnosis was of an EF induced by an ill fitted mandibular denture. The intervention carried out was a combination of a 2 weeks tissue conditioning period followed by a cold blade surgical resection. After a 3 months follow-up period, a completely healed vestibular sulcus was observed with no scar tissue. The present technique facilitates the resection surgery by removing the inflammatory component of the EF. It also guides the post-surgical tissue healing, allowing the obtention of a deep vestibular sulcus, thus creating a better bearing surface for subsequent renewed dentures. Not depriving the patient of her dentures during the healing process helped to improve her quality of life and her cooperation.

The Prosthetic Management of a Case of Epulis Fissuratum by a Novel Technique / El manejo protésico de un caso de épulis fisurado con una técnica novedosa

ABSTRACT: The clinical management of the epulis involves the elimination of causal factors, excision of fibrous tissue excess accompanied by an appropriate prosthetic rehabilitation. The confection of interim prosthesis or the rectification of old prosthesis for the setting up of a tissue conditioner if necessary, to improve the healing and prevent the decrease of the vestibule depth after the surgical exeresis. Throughout this paper, we are going to present a new technique for the correction of old prostheses poorly adapted for the management of a case of the epulis fissuratum.

RESUMEN: El manejo clínico de un épulis comprende la eliminación de los agentes causales y la eliminación del tejido fibroso, acompañado de una adecuada rehabilitación protésica. Es necesaria la confección de una prótesis provisional o la rectificación de la prótesis vieja, para la colocación del acondicionador de tejidos si fuera necesario para mejorar el sanado y prevenir la disminución de la profundidad del vestíbulo después de la exéresis quirúrgica. En este artículo, presentaremos una nueva técnica para la corrección de la prótesis desajustada en el manejo de un caso de épulis fisurado.

Influence of Khat Extract (Catha edulis) on corrosion resistance of Co-Cr dental alloys / Influência do extrato de Khat (Catha edulis) na resistência à corrosão de ligas dentais Co-Cr

Objective: The aim of this experimental study was to assess the effect of khat extract with different concentrations on the corrosion resistance of cobalt-chromium (Co-Cr) dental alloys used for removable denture. Material and Methods:The corrosion resistance of three Co-Cr alloys (Neobond II®, Kera 501® and PD Casta H®) was evaluated in artificial saliva in presence of three different concentrations of khat extracts. Fusayama-Meyer artificial saliva was used as a reference solution. The corrosion properties of the alloys were analyzed using potentiodynamic polarization, electrochemical impedance spectroscopy and surface analysis. The data was presented in means, standard deviations, and related figures. Comparison between the different concentrations was done using 1-way ANOVA test. The surface analysis was performed using scanning electron microscopy (SEM). Results: the results showed that the corrosion resistance of the three alloys tested (Neobond II®, Kera 501® and PD Casta H®) decreased in artificial saliva containing khat extract compared with that of the reference solution. Additionally, the corrosion resistance of the three Co-Cr dental alloys decreased by increasing the concentration of khat extract. Furthermore, the results indicate that Neobond II® alloy showed the least corrosion resistance compared with that of Kera 501® and PD Casta H® alloys. Conclusion: Khat extract with different concentrations had negative impact on the corrosion resistance of Cr-Co alloys. More in-vivo studies are highly recommended to confirm the results of the present study (AU)

Objetivo: O objetivo deste estudo experimental foi avaliar o efeito do extrato de khat em diferentes concentrações na resistência à corrosão de ligas dentárias de cobalto-cromo (Co-Cr) utilizadas em próteses removíveis. Material e Métodos:A resistência à corrosão de três ligas de Co-Cr (Neobond II®, Kera 501® e PD Casta H®) foi avaliada em saliva artificial na presença de três concentrações diferentes de extratos khat. A saliva artificial de Fusayama-Meyer foi usada como solução de referência. As propriedades de corrosão das ligas foram analisadas usando polarização potenciodinâmica, espectroscopia de impedância eletroquímica e análise de superfície. Os dados foram apresentados em médias, desvios-padrão e figuras relacionadas. A comparação entre as diferentes concentrações foi feita usando o teste One-way ANOVA. A análise de superfície foi realizada em microscopia eletrônica de varredura (MEV). Resultados: os resultados mostraram que a resistência à corrosão das três ligas testadas (Neobond II®, Kera 501® e PD Casta H®) diminuiu na saliva artificial contendo extrato khat em comparação com a solução de referência. Além disso, a resistência à corrosão das três ligas dentais Co-Cr diminuiu com o aumento da concentração de extrato de khat. Além disso, os resultados indicam que a liga Neobond II® apresentou a menor resistência à corrosão em comparação com as ligas Kera 501® e PD Casta H®. Conclusão: O extrato de Khat com diferentes concentrações teve impacto negativo na resistência à corrosão de ligas de Cr-Co. Mais estudos in vivo são altamente recomendados para confirmar os resultados do presente estudo. (AU)

Maintaining occlusal stability by selecting the most appropriate occlusal scheme in complete removable prosthesis.

The search of an adequate occlusal scheme that maximizes dentures' stability and patients' satisfaction is an ultimate objective in every complete prosthodontic treatment. Many studies compared occlusal schemes in terms of retention, comfort and masticatory performance. The purpose of this article is to review literature about different occlusal schemes related to complete dentures' stability and edentulous patients' satisfaction, in order to select the most appropriate occlusal scheme. Thus, an electronic search was performed from PubMed (MEDLINE), Scopus, Cochrane, Google Scholar and Sciencedirect databases. 65 articles were identified of which 56 were selected to compose the present article. Within the limitations of this review, it has been concluded that edentulous patients prefer anatomic occlusal schemes to non-anatomic teeth. Furthermore, canine guidance seems to be efficace in terms of chewing comfort and dentures' retention, as well as lingualized occlusion. However, bilateral balanced occlusion does not confer a long-term masticatory performance and satisfaction to edentulous patients.

Effects of sterilization and disinfection procedures on the corrosion of orthodontic ligature cutters.

OBJECTIVE: The objective of our study was to investigate the corrosion resistance of orthodontic ligature cutters subjected separately to two different sterilization procedures, namely, autoclaving and chemical disinfection with main focus on the cutting section of each instrument. MATERIALS AND METHODS: Twenty-four ligature cutters were obtained from three different manufacturers: Hu-Friedy, ETM, and Nadir & Co. The study included a control group (G0) and four experimental groups (G1-4). G1 was subjected to 50 autoclave sterilization cycles. G2, G3, and G4 were subjected to 50 chemical disinfection cycles using, respectively, Peridiol E, Hexanios G+R, and Steranios 2%. Manufacturer recommendations were followed. The instruments' blades were studied via SEM and X-ray microanalysis (EDX spectrum). RESULTS: These cutters have inserts made from various resistant alloys. SEM micrographs revealed different forms of corrosion depending on whether autoclaving or chemical disinfectant sterilization procedures were used, and depending on the alloys present. Chemical disinfection is more aggressive than autoclave sterilization, and is responsible for localized corrosion in the form of pitting. This is more detrimental to the lifespan of orthodontic cutters. CONCLUSION: Sterilization/disinfection procedures should be adapted to the chemical profile of the metal alloys present. Recommendations for use published by instrument manufacturers must be followed.