Mechanical and microstructural analysis of a new model of attachments for overdentures retained by mini-implants obtained by 3D printing with three different polymers

Influence of post-processing on the adhesion of dual-species biofilm on polylactic acid obtained by additive manufacturing

“…PLA has a hydrophobic surface, with a contact angle (CA) of approximately 80°, which promotes a greater affinity for adhesion of equally hydrophobic microorganisms ( Casalini et al, 2019 , Hall et al, 2021 ). This CA can be influenced by the printing parameters inherent in the protocol applied for each experiment since the literature reports the influence of the following on the physical and mechanical properties of PLA ( Brounstein et al, 2021 , de Campos and dos Reis, 2023 , de Campos et al, 2023 , García Plaza et al, 2019 ). Vidakis et al (2020) observed in the printed PLA specimens that the CA is altered depending on the roughness of the surface and the thickness of the layers, with results for 100 μm layers being 84.1° and 300 μm being 78.6° ( Vidakis et al, 2020 ).…”

“…Campos et al (2022) developed attachments for retaining overdentures with PLA using the FFF method and observed excellent retention, hardness, and compression properties. However, attachments are subject to microbial contamination because they are placed in an area that is difficult to clean, which can promote microbial adhesion and subsequent oral and systemic diseases ( de Campos et al, 2023 , de Campos and dos Reis, 2023 , de Campos and dos Reis, 2023 , de Campos et al, 2023 ).…”

“…PLA attachments by FFF have a high surface roughness, which can favor the adhesion of microorganisms since rougher surfaces tend to promote higher biofilm accumulation ( Alp et al, n.d. ; Batak et al, 2021; de Campos et al, 2023 , de Campos and dos Reis, 2023 , Mei et al, 2011 , Vidakis et al, 2020 ), due to the increase of the surface area or being associated with hydrophobicity, electrostatic interactions, and Van Der Waals forces that benefit microbial adhesion (Batak et al, 2021; Vidakis et al, 2020 ). Surface roughness has a major influence on microbial adhesion after the period of biofilm establishment because the microbes can find the best spaces to adhere, such as cracks and pores ( Mei et al, 2011 ).…”

“…Considering the medical and dental application of PLA obtained by FFF, the reduction of biofilm accumulation is paramount to prevent contamination, and infections, and improves hygiene to overcome the surface characteristics that favor microbial adhesion ( de Campos et al, 2023 , de Campos and dos Reis, 2023 ). This study aimed to evaluate the behavior of PLA obtained by FFF against dual-species biofilm, roughness, and wettability with chemical, thermal, and mechanical PP, with and without thermal aging.…”