## 4 Discussion  
PMMA remains the predominant choice for denture base materials. Additives such as polymerization initiators, accelerators, bonding agents, and colorants have been incorporated into the base composition. These additives play a crucial role in shaping the physical and chemical properties of these materials. Among these properties, surface roughness influences the retention of microbial plaque in tissues in contact with the denture base [1; 6; 19]. The inherent physical characteristics of surface roughness are influenced by factors such as the operator's manual dexterity, the polishing protocol employed, and the inherent composition of the material itself. In the literature [4; 21], there is a lack of knowledge concerning the development of an effective mechanical protocol for polishing acrylic resin surfaces. To overcome this  
Figure 4: Height distribution curve—filtered profile ((**A**) Control sample; (**1A**) Mechanized polished samples; (**2A**) Manually polished samples); unfiltered profile ((**B**) Control sample; (**1B**) Mechanized polished samples; (**2B**) Manual polished samples). deficiency, a prototype was developed [1]. The authors proved its validity by determining significant differences between resin groups polished with the prototype (\(p\) = 0.031) [1]. Nevertheless, only differences in average roughness values (Ra) between the groups were assessed. One limitation was the absence of other height parameters to compare both polishing techniques (mechanized and manual). Selecting the most suitable and pertinent surface roughness parameters to monitor desired surface properties is challenging. The need to promptly identify a subset of parameters that correlate with surface functionality has been emphasized [17]. As studied for other materials, the present authors propose the introduction of a primary profile to the analyses of a surface. The primary profile is the most critical aspect of evaluating surface roughness because it directly represents surface details, including peaks and valleys and all height variations [10,14,15]. The main parameter used to characterize the surface roughness of acrylic resins is Ra. It is an optimal value for evaluating the effect of surface polishing and finishing protocols because it considers variations in height and depth roughness [4,9,15,19,21]. However, it only addresses the profile's vertical deviation, failing to offer insights into the slopes, shapes, asperity sizes, or the frequency and regularity of their occurrence [15,16]. These features directly define the functionality of a surface in relation to bacterial adhesion, microbial growth, and stress [17,22]. Pa, directly extracted from the primary profile, can be considered an extension of Ra to the profile, as shown in Table 3. Both represent the deviation of each point's height from the arithmetical mean in different profiles [23]. From a clinical perspective, the significance of Pa is relevant because it addresses the actual profile of the resin surface. Pa represents the average of unfiltered peak and valley distances from the mean surface profile. The observed differences are comparable to the Ra results of the filtering operation, eliminating the deepest asperities of the surface [21]. Significant differences were found in three groups (\(p\) < 0.01) for Ra; however, the heterogeneity among samples for Pa makes it difficult to determine these significant differences. Specific parameters, such as skewness and kurtosis, are described to differentiate surfaces with different shapes and the same value for Pa [14], as described in the values for the mechanical and manual techniques (1.49 \(\pm\) 0.50 \(\upmu\)m) (Table 5). Figure 4(1B,2B), show differences between the distribution curves, respectively.