## 4 Discussion
In some cases, the bone atrophy and the bone itself are asymmetrical, so planning a prosthesis might be challenging. Then, a careful patient evaluation, both on CBCT scans and plaster models is required. The volume of bone and any asymmetry are also related to the residual dentition. It seems that in the authors' work, stereolithographic models based on patients' 3D CBCT scans are accurate enough to plan any prosthodonic treatment; however, the presented study on maxillary asymmetry revealed that even if asymmetry is present, its degree should influence any treatment at all, while teeth loss during time teeth volume and shape might vary. Important bone volume is necessary to maintain the proper stable position for denture fixtures and dental implants. It seems that, most commonly, bone needs special regenerative techniquesto improve its volume and shape for any dental implant placement. In [PERSON] et al. 's study, the individualism of all bone resorption and its volume indicated that the majority of 56.5% needed additional guided bone regeneration procedures, and 43.5% required sinus augmentation procedures [27]. Similar findings related to bone loss and jaw atrophy are important in cases of implant planning then the limited amount of bone is troublesome for denture fixation. Similar to the bone height and proper value, proximity also affects important structures, such as the nasopalatine canal or inferior border of the nasal cavity, and can be troublesome for proper dental implant placement. Anatomical studies indicate that multiple variations of the nasopalatine canal regarding the buccal bone wall and shape/size towards the anterior maxillary plate also influence proper dental implant placement. Furthermore, in edentulous patients, the position of the nasopalatine canal might vary. At first, the degree of the bone condition is related to the presence of teeth. Over time, bone can change and be atrophic. Therefore, the anterior maxillary dimension made by the authors indicates that more anterior palatal depth CBCT remains the diagnostic tool of choice for proper dental planning. So far, no adequate studies on the comparison of CBCT 3D and in vivo specimens of 3D stereolithographic models have been published. Even though anterior and posterior maxillary symmetry is derived not only from the presence of teeth but also from individual bone architecture. CBCT is an accurate tool to investigate the residual bone ridge in the edentulous maxilla for dental implant therapy. The bucco-palatal crest width and coronal bone height in a CBCT measurable study by [PERSON] and [PERSON] [28] estimated that many of the dimensions were too narrow and required additional bone-guided surgery [28,29]. So far, many studies discuss adequate bone volume for dental implant rehabilitation in edentulous patients [29]. The aging process greatly influences dedentulous bone, which results in different maxillary alveolar process volumes. A detailed study by [PERSON] et al. [12] on 100 dry skull specimens described the role of aging/edentulousness on the maxillary arch, the size of the alveolar process, and the shape and thickness of the hard palate in South Indians and explained and customized a more appropriate treatment of elderly edentulous patients. The authors concluded that bone resorption results in a reduction of the width and depth of the alveolar arch concomitant with the alteration of the hard palate. A lack of proper facial vertical height related to edentulous patients and adequate dental treatment or lack of dental prosthesis increases poor facial appearance. Other studies seem to confirm this [13]. It seems that palatal depth and accurate bone dimensions influence denture position. This topic was frequently evaluated world-wide to establish the type of ideal edentulous patient profile for those who require additional bone regenerative procedures or others, to improve their prosthetic rehabilitation. Palatal shape, size, and proportions are also used in other branches of medicine.