## 2 Methodology  
The research was conducted at the Department of Prosthodontics, Faculty of Dentistry, AlZulfi, Al Majmaah University. The research sample consisted of maxillary and mandibular dental casts from patients who required fixed prostheses.  
Inclusion criteria:  
* Dental casts belonged to patients of Saudi Arabian nationality.
* Both mandibular and maxillary dental casts contain both canines.
* All permanent canines did not exhibit any developmental shape anomalies, including double tooth and microdontic.
* All permanent canines showed no signs of caries, loss of tooth structure due to occlusal wear or trauma, or dental or occlusal abnormalities.
* The complete eruption of all canines. Exclusion criteria:
* Dental casts belonged to the non-Saudi Arabian population.
* Dental casts did not have any of the four permanent canines.  
Any of the permanent canines displayed developmental abnormality.
* Any of the permanent canines dental caries and loss of tooth structures due to occlusal wear and dental trauma or dental/oclusal abnormalities.
* Partially erupted or impacted canines. Measurements:  
Maxillary were assigned as 13 and 23, and mandibular canines were assigned as 33 and 43, respectively. Mesiodistal and cervicoincisal crown dimensions (Figure 1) of maxillary and mandibular canines were measured using were recorded with the help of calibrated (0-200 mm/0-8'') digital caliper (0-150 mm/0-6'') (INSIZE Company, Derio, Spain, made in China). A single examiner performed the measurements, and Kappa statistics were used to evaluate intra-examiner reliability. The measured dimensions included were (i) the mesiodistal (MD) width of the maxillary and mandibular canines has been defined as the maximum expanse between the proximal aspects of the crown. (ii) The cervicoincisal (CI) width of maxillary and mandibular canines was defined as the maximum expanse between the cervical and incisal aspects of the crown. Canine measurements on both sides of both arches were recorded. The maximum expanse between the crown's cervical and occlusal aspects is the codimension of the maxillary and mandibular canines. A pilot study was performed using ten maxillary and mandibular dental casts after a two-week washout period. The same examiner repeated the measurements, including mesiodistal and cervicoincisal widths of the canines. These dental casts were not involved in the final study.  
Statistical Analysis:  
Descriptive statistics were used for continuous and non-normally distributed data. Sensitivity and specificity calculations were performed for clinical case definitions. The collected data were statistically analyzed using SPSS software (Version 22.0). The mean, range, and standard deviation were calculated for the size of the teeth. To calculate sexual dimorphism, discriminant statistical analysis and Student's \(t\)-test were used. The Spearman correlation was employed for data analysis to identify the correlation between four permanent canine dimensions. Sex dimorphism in mandibular canines was calculated using the formula by [PERSON] et al. [19]. Sex dimorphism = (Xm \(\div\) Xf \(-\) 1) \(\times\) 100, where Xm  
Figure 1: Illustrating the measurements used to estimate sex dimorphism among the study population.  
represents the mean width of male canines and Xf denotes the mean width of female canines. The statistical analysis was conducted on mesiodistal and cervicoincisal dimensions for teeth 13, 23, 33, and 43, along with an exploration of sex dimorphism. The accuracy percentage of sex identification through this method was later substantiated by contrasting the means and medians of teeth 13, 23, 33, and 43 with the established. A Student's \(t\)-test was used to compare the mean difference of all measurements between males and females. [PERSON]'s correlation matrix was used to identify the correlation of mesiodistal and cervicoincisal widths of all permanent canines. The significance level was set at \(p<0.05\).