# Evaluation of Proximal Contact Tightness and Contact Area of Posterior Composite Resin Restorations
## 3 Results  
The contact tightness values in N (\(\pm\) obtained from the PDPM system are shown in Table 1, and the values obtained from the histogram analysis are shown in Table 2. The tightest contact area was an average of 254.91 \(\pm\) 65.69 N in the distal approval area in the PM group, while an average of 126.96 \(\pm\) 56.84 N was found in the distal approval area in the OM group, and 69.01 \(\pm\) 24.99 N voltage was determined in the distal approval area in the IM group (Table 1). When the contact tightness in the distal approval areas of the teeth was examined, the differences between all groups were statistically significant (\(p\) < 0.05). In addition, when the contact tightness in the distal approval areas of the relevant teeth was examined, higher tension values were obtained in the distal contacts in the PM group, while the tension in the mesial region was higher in the other groups (Table 1). Additionally, the tightest contact area in the mesial region was obtained as an average of 228.26 \(\pm\) 59.17 N in the PM group, and an average tension of 145.96 \(\pm\) 40.81 N was detected in the mesial approximal area in the OM group and 74.65 \(\pm\) 19.18 N in the mesial approximal area in the IM group (Table 1). When the contact tightness in the mesial approximal areas of the teeth was examined, the differences between all groups were statistically significant (\(p\) < 0.05). Class II cavity design contact tightness in Class II (MOD) restorations was found to be lesser when compared to Class II OM and Class II OD restorations (\(p\) < 0.05). In addition, for all matrix types and cavity designs, mesial contact tightness was found to be higher than the distal contact tightness values; however, no statistical significance was found for Class II MOD restorations between the mesial and distal surfaces in all groups (\(p\) > 0.05). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Matrix Type** & \multicolumn{4}{c}{**Cavity Design**} \\ \hline  & **Class II (OM)** & **Class II (OD)** & \multicolumn{2}{c}{**Class II (MOD)**} & \multicolumn{1}{c}{\multirow{2}{*}{_p_}} \\  & **Mesial** & **Distal** & **Mesial** & **Mesial** & **\(p\)** \\ \hline
**Palodent Plus** & \(-\)228.257 & \(-\)254.913 \({}^{\text{a}}\) & \(-\)205.478 & \(-\)204.647 \({}^{\text{a}}\) & \\
**(PM)** & (59.17) & (65.69) & (23.65) & (27.89) & \\
**OmniMatrix** & \(-\)145.961 \({}^{\text{b}}\) & \(-\)126.372 & \(-\)133.256 & \(-\)120.487 \({}^{\text{b}}\) & \\
**(OM)** & (40.80) & (56.83) & (42.86) & (35.33) & \\
**Ivory Matrix** & \(-\)74.650 & \(-\)69.004 & \(-\)67.885 & \(-\)64.753 & \\
**(IM)** & (19.18) & (24.99) & (21.85) & (20.02) & \\
**Control** & 189.687 & 202.411 & 189.687 & 202.411 & 0.764 \\  & (15.48) & (17.75) & (15.48) & (17.75) & \\ \hline \hline \(p\) & 0.003 \({}^{\text{a}}\) & 0.001 \({}^{\text{a}}\) & 0.001 \({}^{\text{a}}\) & 0.001 \({}^{\text{a}}\) & \\ \hline \hline \end{tabular} \({}^{\text{a}}\)The statistically significant differences between groups presented with the same superscripts in the same row. Standard deviations are given in parentheses.  
\end{table} 
Table 1: Contact tightness values (N) obtained from the study. When the values are generalized among all matrix groups in which contact tightness is examined, regardless of the cavity design, the best results are observed in the PM group, followed by OM and IM groups, respectively (\(p<0.05\)). The histogram exhibited that black pixel (void) density in the IM group was calculated more than any other group except in class II MOD restorations (\(p<0.05\)), which shows that this matrix is inadequate in contour creation compared to other matrix types. Additionally, there was a difference in terms of contour between the mesial and distal areas only in the PM group (\(p<0.05\)), while no significant difference was found among the other groups (\(p>0.05\)). When the groups were compared with each other, it was determined that there was a difference in both the mesial and distal approximal areas in all three groups (\(p<0.05\)).