Randomized Controlled Trials in Implant Dentistry: Assessment of the Last 20 Years of Contribution and Research Network Analysis.

The aim of this study was to evaluate the characteristics of randomized controlled trials (RCTs) regarding implant-supported single tooth or fixed partial dentures. We performed searches (PubMed/MEDLINE and Web of Science) to identify all RCTs published from 1996 to 2016 and assessed publication details, study characteristics, international collaboration networks, and characteristics related to the implant-supported treatment. Two reviewers independently screened the titles/abstracts and selected full texts. A total of 122 RCTs were included, and most of the authors were from Europe (72%). Most trials did not report a trial registering number (89.9%) or sample size calculation (58.2%). The use of the CONSORT Statement increased over the past 9 years. Trials were mostly conducted at universities (54.9%), and only 13.1% compared 2 or more implant brands. Loading protocol was the most prevalent main comparison among the included studies, and most of the RCTs did not clearly report whether they excluded patients with known risk factors. The studies reviewed here presented different methodological and publication characteristics, and many did not show aspects aligned with current research practices.

Influence of Cross-Section Design and Vertical Misfit on Stress Distribution in Overdenture Retaining System: 3-Dimensional Finite Element Analysis.

PURPOSE: To evaluate by 3-dimensional (3-D) finite element analysis the stress generated on overdenture-retaining bar system with different cross sections (round, ovoid, or Hader) and misfit levels (50, 100, and 200 µm) manufactured with different metallic alloys (Au type IV, Ag-Pd, Ti cp, and Co-Cr). MATERIALS AND METHODS: Three-dimensional finite element models were modeled using specific 3-D software (SolidWorks) and imported into mechanical simulation software (ANSYS). A displacement simulating the settlement of the screw was performed until the infrastructure was settled properly on the prosthetic platform. RESULTS: Higher misfit levels caused higher stress on the overdenture-retaining bar system components, where (1) Hader bar presented the highest values (bar = 730.71; screw = 59.66, and periimplant bone tissue = 42.96, in megapascal) and (2) round bars made with type IV Au alloy presented lower stress values on the bar framework (193.99 MPa) and screw (10.27 MPa). CONCLUSIONS: Higher vertical misfit increased the stress values on the overdenture-retaining bar system; complex cross-sectional designs increased stress values on the bar framework, prosthetic screw, and periimplant bone tissue; stiffer alloys caused higher stress values on all the studied conditions.

Influence of different mucosal resiliency and denture reline on stress distribution in peri-implant bone tissue during osseointegration. A three-dimensional finite element analysis.

OBJECTIVE: The aim of this study was to evaluate the influence of mucosal properties and relining material on the stress distribution in peri-implant bone tissue during masticatory function with a conventional complete denture during the healing period through finite element analysis. MATERIALS AND METHODS: Three-dimensional models of a severely resorbed mandible with two recently placed implants in the anterior region were created and divided into the following situations: (i) conventional complete denture and (ii) relined denture with soft lining material. The mucosal tissue properties were divided into soft, resilient and hard. The models were exported to mechanical simulation software; two simulations were carried out with a load at the lower right canine (35 N) and the lower right first molar (50 N). Data were qualitatively evaluated using Maximum Principal Stress, in MPa, given by the software. RESULTS: All models showed stress concentrations in the cortical bone corresponding to the cervical part of the implant. The mucosal properties influenced the stress in peri-implant bone tissue showing a different performance according to the denture base material. The simulations with relined dentures showed lower values of stress concentration than conventional ones. CONCLUSIONS: It seems that the mucosal properties and denture reline have a high influence on the stress distribution in the peri-implant bone during the healing period.

Cannabidiol in Dentistry: A Scoping Review.

Cannabidiol (CBD) has been gaining increased attention in contemporary society but seems to have been little explored in dentistry. This scoping review mapped the scientific and technological scenarios related to the use of CBD in dentistry. Peer-reviewed publications were searched in five international databases, patents were searched in five technological platforms. In total, 11 articles and 13 patents involving CBD in dentistry-related applications were included. The countries contributing to most articles were Brazil (27.3%) and USA (18.2%). The studies involved experiments on animals (63.6%) and/or using bacteria or cells (36.4%), and no clinical study was found. Three different applications of CBD were observed: periodontal therapy (45.4%), aid for bone regeneration (27.3%), and general use in oral therapies (27.3%). Patent inventors were based in China (53.8%) or USA (46.2%). The patent claims were mainly compositions for oral care, tooth whitening, injury repair, antifungal, anti-inflammatory, and analgesic effects. A total of 76.9% of the patents were filed in association with a company. In general, research suggests that CBD has promising biological properties for applications in dentistry, whereas patents indicate that the current interest of industry relies on compositions for oral care. There appears to be extensive room available for research and technological applications of CBD in dentistry.

COVID-19 pandemic and its impact on dental students: A multi-institutional survey.

PURPOSE/OBJECTIVES: To investigate dental students' perceptions and concerns regarding the COVID-19 pandemic, their coping strategies and support resources, and their perceived stress levels. METHODS: A customized 19-item survey and the perceived stress scale (PSS) were applied to undergraduate dental students from the US, Spain, Ireland, Chile, India, and Brazil between April 10 and July 5, 2020. Linear modeling and mediation analysis were used to explore the relationships among demographics, stressors, coping mechanisms, social support, and stress RESULTS: A total of 4475 students responded to the survey. The majority (72.4%) were women, and 52.3% had no COVID-19 training at the time of the survey. The students reported that they had to accommodate to changes in patient care (96.6%) and didactic learning (95.2%) activities, while 88.5% of the respondents indicated at least one of their courses moved online. Transition to online courses went "smoothly with some troubles" for 51.8% of the respondents, and 48.3% perceived the faculty as prepared for the online transition; however, 45.9% reported feeling extremely concerned about the impact of COVID-19 on their education. The average PSS score was 21.9 of 40 (moderate stress). Multivariate models were built for participants with full data (n = 3899). Being male, having completed more dental coursework, and perceiving a smoother transition were associated with lower PSS scores; more concern about academic progress was associated with higher PSS. Faculty support mediated the relationship between a smoothness of transition and concern about academic progress and PSS scores CONCLUSION: Stress caused by the pandemic may be alleviated by smoother transition and good faculty support.

Effects of use of anabolic steroids on the masticatory system: a pilot study.

The use of androgenic anabolic steroids (AAS) has increased significantly among athletes in Brazil and other countries. These drugs alter the physiological behavior of bone and muscles, also affecting these structures in masticatory system. This paper aims to evaluate bone and dental changes in users of AAS, as well as the incidence of temporomandibular dysfunction (TMD), compared to athletes not using AAS. Eight athletes were equally divided in two groups, AAS users and non-users. The groups were evaluated using Helkimo index, McNamara cephalometric tracing and cast analysis. The AAS users presented more intense TMD signs and symptoms (Di total value, P = 0.096, Mann-Whitney test), increased cephalometric measures (Co-A, P = 0.020, Mann-Whitney test) and Angle Class II malocclusion, compared to the non-users. These results suggested that the use of AAS alters masticatory structures and increases the incidence of TMD.

Adaptation of overdenture-bars casted in different metals and their influence on the stress distribution: a laboratory and 3D FEA.

Adaptation at the implant/abutment interface is important to the long-term success of prosthetic rehabilitations. The aim of this study was to evaluate the adaptation of overdenture bar frameworks casted with different materials and the stress distribution of ill-fitted frameworks placement through 3-D finite element analysis (FEA). Thirty overdenture bar frameworks (n=10) were casted in different materials (Co-Cr, Ni-Cr, Ti). Vertical misfit of both abutments was examined using a single screw test and, after both screws were tightened, using a scanning electron microscope (SEM). The misfit values of each group were used to construct 3-D models, and a displacement with the same extent observed in SEM was applied to the non-tightened abutment to simulate the effect of prosthetic tightening. von Mises stress for prosthetic components, and the maximum principal stress and microstrain for bone tissue were evaluated. The misfit in the non-tightened abutment during the single screw test ranged from 145 to 211 µm. Different bar framework materials did not present significant differences in regard to adaptation. An increase in the misfit values in the other abutment was observed after the final settlement of the bars in Ni-Cr and Ti frameworks. The stress values on prosthetic screw and implant were not influenced by the bar framework material. However, Ti caused lower stress in the bar framework itself and strain in the bone tissue. The bar framework material does not affect the implant/abutment adaptation. Titanium frameworks presented the best behavior for the bar framework itself and bone tissue compared to the other materials.

Stress distribution in fixed-partial prosthesis and peri-implant bone tissue with different framework materials and vertical misfit levels: a three-dimensional finite element analysis.

The purpose of this study was to evaluate the influence of superstructure material and vertical misfits on the stresses created in an implant-supported partial prosthesis. A three-dimensional (3-D) finite element model was prepared based on common clinical data. The posterior part of a severely resorbed jaw with two osseointegrated implants at the second premolar and second molar regions was modeled using specific modeling software (SolidWorks 2010). Finite element models were created by importing the solid model into mechanical simulation software (ANSYS Workbench 11). The models were divided into groups according to the prosthesis framework material (type IV gold alloy, silver-palladium alloy, commercially pure titanium, cobalt-chromium alloy, or zirconia) and vertical misfit level (10 µm, 50 µm, and 100 µm) created at one implant-prosthesis interface. The gap of the vertical misfit was set to be closed and the stress values were measured in the framework, porcelain veneer, retention screw, and bone tissue. Stiffer materials led to higher stress concentration in the framework and increased stress values in the retention screw, while in the same circumstances, the porcelain veneer showed lower stress values, and there was no significant difference in stress in the peri-implant bone tissue. A considerable increase in stress concentration was observed in all the structures evaluated within the misfit amplification. The framework material influenced the stress concentration in the prosthetic structures and retention screw, but not that in bone tissue. All the structures were significantly influenced by the increase in the misfit levels.

Cleaning methods for removable dentures: a critical reviewof the literature

A literature review was performed including studies that evaluated the use of cleaning protocols for removable dentures through questionnaires, clinical trials, randomized clinical trials, and systematic reviews. Twenty studies were included and the results showed that bad preservation of the prostheses is mainly due to low knowledge about cleaning habits and methods. Also, a wide variety of effective cleaning methods were presented. However, there is no standard protocol for all patients and it should be customized for each patient. It is important to highlight that dentists should give adequate instructions concerning maintenance and hygiene of the prosthesis.

Uma revisão da literatura foi realizada incluindo estudos que avaliaram o uso de protocolos de limpeza para próteses removíveis através de questionários, ensaios clínicos, estudos clínicos randomizados e revisões sistemáticas. Vinte estudos foram incluídos e os resultados mostraram que a má preservação das próteses é principalmente devido ao baixo conhecimento sobre os hábitos e métodos de limpeza. Além disso, foram apresentados uma grande variedade de métodos de limpeza eficazes. No entanto, não existe um protocolo padrão para todos os pacientes, devendo ser personalizado para cada paciente. É importante destacar que os dentistas devem dar instruções adequadas quanto a manutenção e higiene das próteses.