A systematic review and meta-analysis of the clinical performance of implant-supported overdentures retained by CAD-CAM bars

Currently, there is no consensus on the indications and clinical performance of implant-supported overdentures (IODs) involving computer-aided design and manufacturing (CAD-CAM) bars. Objective: To evaluate the performance of IODs involving CAD-CAM bars. Methodology: A comprehensive search of studies published until May 2023 was conducted in many databases, including PubMed/MEDLINE, Web of Science, Cochrane Library, and SciELO, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The population, intervention, comparison, outcome (PICO) question was: “How do IODs retained by bars fabricated by CAD-CAM technology perform in daily clinical practice?” The meta-analysis included clinical studies based on effect size and a two-tailed null test with a 95% confidence interval (CI). Results: Ten studies were included in the meta-analysis. Among them, nine reported a 100% implant survival rate for all CAD-CAM milled bars. Complications were reported in two studies with CAD/CAM-milled titanium bars, and one study reported more fractures in soldered gold bars used in maxillary rehabilitation. However, no fractures were observed in IODs retained by PEEK and zirconia bars. According to six studies, biological complications, including peri-implantitis, were minimal in the BioHPP and PEEK bar groups, while no cases were reported in the titanium or zirconia bar groups. CAD-CAM-milled zirconia bars had higher plaque and bleeding indices compared with titanium bars, as evidenced by findings from five studies. All four studies that evaluated Oral Health Impact Profile (OHIP) scores showed a positive effect of IODs retained by CAD-CAM milled titanium bars on quality of life. Patient satisfaction and acceptance by prosthodontists were significantly high, according to the results of five studies. Conclusion: Overdentures retained with CAD-CAM milled titanium bars show great potential for use in daily clinical practice. Moreover, patient and practitioner satisfaction was very high when this method was used

Synthetic and Biological adhesives influence on the ability of Candida albicans in forming biofilms on different PMMA surfaces

A aderência de microrganismos aos materiais que constituem as próteses e aos tecidos bucais é um fator determinante para a colonização microbiana, o que pode desencadear, em principal, infecções como a estomatite protética (EP). A aderência de microorganismos a superfície da prótese esta relacionada as características de superfície da resina acrílica, assim, a fim de minimizar esta aderência o objetivo do presente estudo foi avaliar se adesivos a base ethil cianocrilato possui efeito sobre a adesão de C. albicans por 7, 14 e 30 dias e se a incorporação de Punica Granatum e digluconato de clorexidina no biopolimero de fibrina a base de veneno de cobra possui efeito sobre a formação de biofilme de C. albicans após 24, 48 e 72 horas sobre superfície de resina termo e pré polimerizada (Cad-Cam). Amostras circulares (10 × 2 mm), com uma rugosidade superficial de 2-3 m, foram produzidas. Para ensaios com ethil cianoacrilato, os espécimes foram divididos em 3 grupos: controle (sem tratamento prévio), ethil cianoacrilato convencional e ethil cianoacrilato gel. Foram aplicadas duas camadas contendo 50 L de cada material. O ensaio de unidades formadoras de colônias (UFC) foi utilizados para quantificar as células vivas do biofilme em resina acrílica termopolimerizável pré-tratada, após 7, 14 e 30 dias de desenvolvimento de biofilme. Os dados foram avaliados usando ANOVA e teste de Tukey para análise post hoc (P = 0,05). Para ensaios com o biopolimero de fibrina, os espécimes foram divididos em 4 grupos: CT (grupo controle), sem tratamento de superfície; revestimento de biopolímero de fibrina (FB); biopolímero de fibrina com Punica Granatum (FBPg); biopolímero de fibrina com digluconato de clorexidina (FBCh). As amostras foram inoculadas com C. albicans SC5314 (1x107 células / mL) e incubadas por 24, 48 e 72 horas. Para quantificar a biomassa total do biofilme e as células vivas do biofilme em todas as amostras foram realizados ensaios de UFS e cristal violeta (CV). Uma análise qualitativa foi realizada utilizando microscopia confocal de varredura a laser. Os dados foram analisados estatisticamente por ANOVA 3 critérios (p <0,05). Ambos os adesivos de ethil cianoacrilato reduziram significativamente a formação de biofilme (P <0,05) em comparação com o controle em todos os períodos avaliados (24, 48e 72 horas). Os grupos FBPg e FBCh apresentaram capacidade inibitória nos biofilmes de Candida albicans em todos os períodos e em ambos os materiais avaliados, destacando o FBCh que apresentou melhor desempenho (p <0,05). Todos os grupos apresentaram um aumento no desenvolvimento de biofilme após 72 horas de desenvolvimento de biofilme (p <0,05). Não foi encontrada diferença estatística entre os diferentes materiais a base de PMMA, exceto no grupo FB. Observou-se um potencial para prevenir e controlar a formação de biofilme fúngico sobre PMMA com o revestimento com adesivos a base de ethil cianocrilato e com biopolímero de fibrina incorporado com digluconato de clorexidina e P. granatum.The adherence of microorganisms to the base materials of dentures and on oral tissues is a determining factor for microbial colonization. This can trigger infections such as denture stomatitis (DS). The adhesion of microorganisms to the surface of the prosthesis is related to the surface characteristics of the acrylic resin. Therefore, in order to minimize this adhesion, the present study aimed to evaluate whether adhesives based on ethyl cyanoacrylate had an effect on the adhesion of Candida. albicans after 7, 14, and 30 days, and whether the incorporation of Punica Granatum and chlorhexidine in a fibrin biopolymer derived from snake venom had an effect on the formation of C. albicans biofilm after 24, 48, and 72 h on a heat-polymerized and pre-polymerized resin (computer-assisted design/computer assisted manufacturing/Cad-Cam). Circular samples (10 × 2 mm) with a surface roughness of 2-3 m were produced. For tests with ethyl cyanoacrylate, the specimens were divided into three groups: control (without previous treatment), conventional ethyl cyanoacrylate, and ethyl cyanoacrylate gel. Two layers containing 50 L of each material were used. Colony-forming units assay was used to quantify the living cells of the biofilm in pre-treated thermopolymerized acrylic resin after 7, 14, and 30 days of biofilm development. The data were evaluated using one-way analysis of variance (ANOVA) and Tukeys post-hoc test for post hoc analysis (P = 0.05). For tests with the fibrin biopolymer, the specimens were divided into four groups: CT (control) without surface treatment, fibrin biopolymer (FB) coating, fibrin biopolymer with Punica Granatum (FBPg), and fibrin biopolymer with chlorhexidine digluconate (FBCh). The samples were inoculated with C. albicans SC5314 (1 × 107 cells/mL) and incubated for 24, 48, and 72 h. The tests of colony-forming units and violet crystals were used to quantify the total biomass of the biofilm and the living cells of the biofilm in all the samples. Qualitative analysis was performed using confocal laser-scanning microscopy. The data were analyzed statistically using ANOVA with three factors (p <0.05). Ethyl cyanoacrylate adhesives significantly reduced biofilm formation (P <0.05) compared to the control in all the evaluated periods (24, 48, and 72 h). The FBPg and FBCh groups showed an inhibitory capacity to the biofilms of C. albicans in all the periods. Both materials evaluated highlighting the FBCh showed the best performance (p <0.05). All groups showed an increase in biofilm development after 72 h (p <0.05). No statistical difference was found between the different materials based on polymethylmethacrylate (PMMA), except in the FB group. There was a potential to prevent and control the formation of fungal biofilms on PMMA coated with adhesives based on ethil cyanocrilate and fibrin biopolymer incorporated with chlorhexidine digluconate and P. granatum