## 1 Introduction  
Skull base growth has a crucial effect on the position of the maxilla and mandible, which in turn affects the skeletal pattern and dental occlusion [1]. The cranial base forms the floor of the cranial cavity and affects the growth pattern of skull regions, which includes the nasal cavity, oral cavity, and pharynx [1]. Because of the cranial base's impact on craniofacial functions and esthetics, the relationship between the cranial base and malocclusion has been a subject of interest for researchers for many years [2].  
The cranial base has an impact on the sagittal relationship between the maxilla and mandible [3]. For instance, the cartilages formed in the anterior cranial base segment affect the formation and growth of the maxilla [4]. On the other hand, the size and shape of the posterior cranial base influence the anteroposterior position of the mandible [5]. Previous studies have investigated the cranial base and maxillomandibularbular relationship, but the results were inconclusive, and different hypotheses were suggested [6,7]. For example, a study found that class III malocclusion has smaller linear and angular cranial base measurements, while others failed to show a reduced cranial base length in skeletal class III [8,9]. It is important to mention that environmental context and ethnic variations in the genetic background could play a role in cranial base dimensions [10,11]. Given these controversial results, we focused on the Saudi Arabian population.  
The main limitation of previous studies was the use of two-dimensional (2D) cephalometric radiographs to estimate the relationship between the three-dimensional (3D) cranial base and malocclusion [7; 11]. Another limitation of the 2D cephalometric analysis was the superimposition of deep landmarks, such as Basion and Sella turcica [11]. Moreover, a meta-analysis reported no sufficient evidence regarding the relationship between the posterior cranial base and sagittal jaw discrepancies [7]. To the best of our knowledge, this is the first orthodontic research to investigate the relationship between the cranial base and maxillomandibular relationship using cone-beam computed tomography (CBCT) images. The study aims to obtain a more accurate reading by using CBCT radiographs in order to identify the relationship between the sagittal and transverse cranial base and maxillomandibular relationship. The null hypothesis in this study is that there is no association between the sagittal and transverse cranial base and maxillomandibular relationship. This study provides a vertical gain of knowledge in cranial base characteristics of different skeletal malocclusions and sets landmarks to improve orthodontic diagnosis and treatment planning. Since cranial base abnormalities might be associated with skeletal malocclusion occurrence, understanding cranial base morphological features might contribute to early diagnosis of skeletal malocclusion and create a good foundation for accurate treatment planning [12; 13; 14]. Therefore, this study provides various cephalometric characteristics for a specific racial group with particular reference to early orthodontic diagnosis and treatment planning.