## 3 Results  
The results of the weighted Kappa revealed substantial agreement between the inter- and intra-examiner reliability (Kappa \(\geq\) 0.8). A total of 2226 pediatric patient records were reviewed. Of these, 1194 records met the inclusion and exclusion criteria and were included in this study. However, the final regression analysis was performed on full, complete records without missing data (\(n\) = 888) (Figure 1). Table 1 presents the demographical distribution of the study participants. The data contained an almost equal distribution of males and females (53% and 47%, respectively), with a mean age of 7.5- \(\pm\) 2-years-old. They were mostly Saudis (79%) who were healthy, with no significant medical history (91%). Based on the patient records, only 20% of the patients were identified as uncooperative (rated as negative or definitely negative on the FBRS). The means of the sound, decayed, and filled distal surfaces of the first primary molars were 1.64, 1.89, and 0.17, respectively. On the other hand, the means of the sound, decayed, and filled medial surfaces of the second primary molars were 1.91, 1.71, and 0.17, respectively (Figure 2). Table 2 presents the Pearson correlations between the distal surfaces of the first primary molars and the mesial surfaces of the second primary molars. There was a high positive correlation of 0.61 between the decayed distal surfaces of the first primary molars and the mesial surfaces of the second primary molars. Additionally, the sound surfaces and filled surfaces of the distal first primary molars were highly positively correlated with similar surface conditions in the mesial of the second primary molars (0.66 and 0.6, respectively). \begin{table}
\begin{tabular}{c c} \hline \(n\) (\%) & \\ \hline
**Gender \(n\) = 1194** & 634 (53.1) \\ Male & 560 (46.9) \\ Female & \\ \hline
**Nationality \(n\) = 1194** & 942 (78.9) \\ Saudi & 252 (21.1) \\ Non-Saudi & \\ \hline
**Medical History \(n\) = 1194** & 1087 (91.0) \\ Healthy & 107 (9.0) \\ Non-healthy & \\ \hline
**Patient Behavior \(n\) = 888** & 710 (80.0) \\ Cooperative & 178 (20.0) \\ Non-cooperative & \\ \hline
**Mean \(\pm\) SD** & \\ \hline Age (years) \(n\) = 1194 & 7.51 \(\pm\) 2.0 \\ \hline \end{tabular}
\end{table} 
Table 1: Description of the study participants. Figure 1: Flow chart of the study participants. Table 3 shows the linear regression models used to determine the influence of patient behavior on the association between similar adjacent surfaces of the primary molars. Based on the results from those models, B estimates of the sound, decayed, and filled distal surfaces of the first primary molars were the strongest predictors of similar sound, decayed, or filled surfaces in the mesial surfaces of the second primary molars (B = 0.62, 0.61, and 0.61, respectively). These estimates were statistically significant in crude and adjusted models. Compared to cooperative patients, the adjusted estimate of the mean decayed mesial surfaces of the second primary molars was estimated to increase significantly for non-cooperative patients by 0.1 (95% CI = 0.16-0.53), and the adjusted R-squared = 0.4. On the contrary, the adjusted estimate of the mean sound mesial surfaces of the second primary molars significantly decreased by 0.09 for non-cooperative patients, as compared to those who were cooperative, with a 95% CI of \(-\)0.52--0.15, and the adjusted R-squared = 0.4. However, patient cooperation did not significantly influence the mean estimate of the filled mesial surfaces of the second primary molars (adjusted B-estimate 0.01 with a 95% CI of \(-\)0.05-0.09), and the adjusted R-squared = 0.4. Additionally, an increase in patient age was associated with a 0.06 increase in carious mesial surfaces of the second primary molars in crude and adjusted models. Patient age only had an inverse relationship with the mean of the sound mesial surfaces of the second primary molars in the univariate model.