## 1 Introduction  
The microimplant-assisted rapid palatal expansion (MARPE) treatment has been extensively described in the literature and noted for its ability to reduce excessive load on the buccal periodontal ligament of the teeth used as anchorage [1]. MARPE devices combine both bone and dental elements, achieving retention through four bicortical microscrews that penetrate the palatal cortical bone and extend to the nasal floor [2]. This technique is particularly effective for adult patients in which the ossification of the midpalatal suture hinders the separation of the maxillary halves when conventional expanders are the elective technique [3, 4].  
To ensure the correct placement of the expansion device and the bicorticality of microimplants, it is essential to conduct a thorough case study that must include a CBCT (Cone Beam Computed Tomography) scan of the patient [4]. Haga clic o pulse aqui para escribir texto. CBCT can be used to quantitatively evaluate the dental [5], skeletal [6], and upper airway [7] impacts of MARPE treatment. Additionally, it enables the generation of volumetric images, providing a detailed assessment of the anatomy without the overlap of adjacent structures [4]. Some of the disadvantages of CBCT include increased scattered radiation, the limited dynamic range of the X-ray area detectors, artefacts, and the lack of accuracy regarding Hounsfield units (HUs), compared with medical computed tomography (CT) [8]. HUs are defined as linear transformations of the X-ray attenuation coefficients measured from a material, referenced against water [9]. According to the scientific literature, it is feasible to use HUs based on the grey scale values shown in conventional computed tomography (CT), correlating them with bone density [10]; thus, a relationship has been established between the HU values calculated in conventional CT and the grey scale that can be studied in CBCT [8]. Because of all these characteristics and also due to its lower radiation dose compared to conventional CT, CBCT is nowadays considered the standard procedure to measure bone density in dental implantology [11].  
The outcome of MARPE is closely linked to the patient's age, with older patients facing lower success rates. Research indicates that younger individuals, particularly those between the ages of 15 and 19, experience a success rate of approximately 83.3%, whereas for those between 30 and 37, the rate decreases significantly to 20% [12]. Those results are consistent with other research studies [13,14]. This reduction is believed to be related to the increasing ossification and rigidity of the midpalatal suture as individuals age, which makes the suture less responsive to expansion forces. Additionally, other factors like the thickness and density of the posterior palatal bone could also contribute to success, with less ossified regions showing better outcomes [14,15].  
Sex, on the other hand, does not significantly appear to influence MARPE results. Studies have found no major differences in the success rates between males and females, suggesting that sex-specific anatomical variations do not substantially affect the procedure's efficacy [10,11].  
Thus, the maturation stage of the suture and the precise placement of mini-implants remain critical factors that can affect the outcome, highlighting the importance of thorough preoperative evaluation.  
As a result of all the above, the present investigation aims to examine whether the efficacy of midpalatal suture expansion, achieved through microimplant-assisted rapid palatal expansion (MARPE), is significantly influenced by variables such as age, sex, the maxillary width, or the suture bone density. Furthermore, this study seeks to analyze potential variations in bone density across the anterior, middle, and posterior regions of the midpalatal suture, and to evaluate the impact of these density disparities on the success or failure of the expansion process.