## 4 Discussion  
The aim of the present study was to determine the prevalence of carotid artery calcification and its relationship with other risk factors of cardiovascular disease such as age, gender, systemic diseases (diabetes, hypertension), smoking along with the determination of alveolar bone loss and periodontal risk. To the best of our knowledge, this is perhaps the first study in Saudi Arabia to determine the relationship between CAC and periodontitis. Prior studies in Saudi Arabia focused on the prevalence of carotid artery calcification and risk factors in the general population [42; 43; 44]. However, we did not find studies in Saudi Arabia depicting the relationship between CAC and periodontitis in terms of the alveolar bone loss and periodontal risk. In 1981, [PERSON] and [PERSON] first detected carotid artery calcification in panoramic radiographs [33]. They highlighted the importance of assessing the carotid artery calcification in a panoramic radiograph in routine dental practice. Thereafter, many researchers began to study the relationship between CAC-associated risks and cardiovascular lesions using panoramic radiography thereby enhancing its use in detecting CAC [47; 48; 49; 50]. In this study, the prevalence of CAC was found to be 5%. This is in agreement with the findings of [PERSON] [42] who also reported similar prevalence of CAC in the general dental population in 2012 with the sample size (\(n=555\)) similar to that in the present study (\(n=500\)). Some studies have also reported lower prevalence of 2.9% [51], 3.1% [3] and 2.43% [52], while others have reported higher prevalence of 9% [53], 6.8% [54] and 9.4% [55]. This variation in prevalence could be due to the differences in the sample size, sample population, age, dietary habits and lifestyle. In our study, most of the detected cases of CAC were presented bilaterally (52%). A higher bilateral distribution was also reported by [PERSON] et al., 2015 [56], [PERSON], 2018 [54], and [PERSON] et al., 2009 [15]. In terms of unilateral distribution (right side or left side), more cases were observed on the left side compared to the right side (20%). Similar greater left-side distribution was also reported by [PERSON], 2012, [PERSON], 2015, and [PERSON] et al., 2005 [56; 57; 42]. However, some studies also reported more CAC on the right side [53; 58; 59]. CAC appears to be more often in female patients. In our study, higher prevalence of CAC (4.92%) was found in female patients as well. High female prevalence was also reported by other studies [54; 53; 54; 56; 57]. In our study, the difference between gender and CAC was statistically significant, which is similar to that in the study of [PERSON] et al. conducted on a Brazilian population [60]. This could be due to the changes in the estrogen level after menopause. Estrogen results in the formation of atheromatous plaque by acting on the lipoprotein metabolism. A reduction in the estrogen level after menopause precipitates this reduction in plaque [34]. [PERSON] et al. [59] studied the PRs of female patients with a history of amenorhea and found that 31% of the radiographs showed CAC. Similar findings were also reported by [PERSON] et al., 2015, with 22.9% prevalence of CAC in women in 1214 panoramic radiographs [61]. However, CAC predominance in males was also reported in some studies [62; 63; 42]. In their study, [PERSON] et al. [58] also had twenty-five female and eight male patients with CAC. This is similar to the present study's findings of twenty-three females and two males having CAC. The mean age of the patients in which CAC was absent (\(n=475\)) was 54 years, whereas, for the 25 patients in which CAC was found, their mean age was 56 years. This supports the findings of other studies in which the prevalence of CAC increased with age [3; 60; 64]. [PERSON] et al. also reported that CAC (+) is associated with increasing age, showing more CAC instances in the 50-70-year age group, with a mean age of 54 years [60].