## 1 Introduction  
Acrylic resins are used for various applications in dentistry, such as denture base materials. The most common material used for denture base is poly (methyl methacrylate) (PMMA) [1]. Among PMMA properties, surface roughness emerges as a clinically significant factor, directly or indirectly impacting microbial plaque retention in tissues in contact with the denture base. A clinical threshold, devoid of statistical relevance to microbial colonization, was established at 0.2 \(\upmu\)m [2]. Beyond this value, the potential for pathological conditions, such as prosthetic stomatitis and oral candidiasis, rises due to microbial accumulation. To counteract this, mechanical and chemical polishing processes on the prosthetic base surface are recommended to enhance the material's biocompatibility [3, 4, 5]. The surface roughness of dental acrylic resins is mainly affected by acrylic resins' inherent features, the polishing technique, and the operator's manual skills [1, 4, 6]. The authors of the present study propose a mechanical device for polishing acrylic resins, regardless of the individual operator's skills. When assessing surface roughness, this variable should be excluded [1]. Different surfaces exhibit different tribological properties, with surface roughness performing a major role [7]. Functional performance is significantly correlated with surface finish, encompassing surface texture, and the mechanical characteristics of the surface [8; 9]. Manipulating surface roughness affects the mechanism and structure of acrylic resins, not only from the visual aspect but also from a clinical perspective, since it extends to properties such as fatigue life, wear resistance, corrosion resistance, and micro-organism deposit formation or colonization on acrylic resins [9]. To characterize and classify different surfaces, surface roughness parameters were developed and standardized through the American National Standard Institute (ANSI) and the International Organization for Standardization (ISO) [10]. ISO 4288:1996 [11] has presented rules and procedures to assess surface texture. In general, profilometers are the most used contact instrument for measuring surface roughness, quantifying it based on the recorded surface height. The operating principle of the device consists of a diamond tip in contact with a surface that performs a straight-line scan, where height variations are converted into electrical signals, referred to as micrometric magnitudes. The measurements obtained only represent two dimensions (2D), considering that the tip only moves vertically and horizontally along a central line [12; 13]. From a graphical perspective, surface roughness corresponds to variations in height on a surface relative to a reference plane [10; 14; 15]. However, profile graphs do not provide the quantitative data required to estimate the functional value of a surface [14; 16]. Such data can be extracted from surface profile graphs by analyzing statistical parameters. These parameters measure the vertical (amplitude), the horizontal deviations (spatial), or a combination of both amplitude and spatial aspects [12; 13; 14]. This challenge emerges from the need to select suitable surface parameters for monitoring whether the desired functional surface properties are met [17]. The most common metric to analyze surface roughness is Ra (the arithmetic average of the absolute values of the profile height deviations from the mean line, recorded within the evaluation and length). Although this parameter provides a good overall description of height variations, it does not provide information relative to the shape of the surface and does not provide information about the frequency and regularity of their occurrence [1; 7; 14]. It also lacks details about wavelengths and is not responsive to minor changes in the profile. For example, different authors [10; 14] describe the possibility of the same Ra value for a surface with profiles of different shapes and frequencies.