## 3 Results  
Table 1 presents the average compressive strength values (cracking stage and destruction stage) in each group. The analysis of variance (ANOVA) showed a statistically significant difference, F = 121.25995, and the \(p\)-value was <0.00001 (Table 1). Figure 3: Samples subject to dynamic loading in a computer-controlled dual-axis chewing simulator (Chewing Simulator CS-4; SD-Mechatronik, Westerham, Germany). The results indicate that the arithmetic mean for Group A was statistically significantly different from those of Groups C and D. However, Group A did not show a significant difference from Group B. No statistical difference was found between the groups with lithium disilicate onlays and those with ceramic-infiltrated composite onlays. In contrast, a statistically significant difference was observed between onlays made of monolithic zirconia and those made of printed composite. The 3D-printed polymer-based composite resin onlays exhibited the highest resistance to breakage, followed closely by the monolithic zirconia onlays. Both of these groups displayed a statistically significant difference when compared to the other groups. The data indicate that the resistance of the restoration is influenced by the specific material used. All samples exhibited visible destruction of the adhesive bond and degradation of the monolithic restoration. A distinct pattern of fracture behaviour was observed: fractures predominantly occurred in the region of the cavity isthmus, with the fracture line appearing to be horizontal, leading to the inlay restoration being divided into two uneven halves. Additionally, the two proximal boxes became separated, and the cusp coverage fractured into numerous small pieces (Figure 4a,b). Group A consisted of monolithic lithium disilicate onlays, Group B included monolithic ceramic-infiltrated composite onlays, Group C consisted of 3D-printed polymer-based composite resin onlays, and Group D comprised monolithic zirconia onlays. Observations were conducted for each of the four groups, and an analysis of variance was performed to compare the compressive strengths of the onlays. The average force required for each group's cracking stage was as follows: Group A, 871; Group B, 728; Group C, 2655; and Group D, 2005. Additionally, the compressive strength (destruction stage), indicating the force at which the samples were completely destroyed, was as follows: Group A, 2516.5; Group B, 2266; Group C, 5670; and Group D, 3543. Based on these average values, it can be concluded that the materials used in Group C exhibited the greatest resistance (Figure 5a,b and Figure 6a,b). \begin{table}
\begin{tabular}{c c c} \hline \hline  & \multicolumn{2}{c}{**Compressive Strength Test**} \\ \hline
**Test Groups** & **Cracking Stage (N)** & **Destruction Stage (N)** \\ \hline Group A & 871.4 \(\pm\) 35.164 & 2516.5 \(\pm\) 242.402 \\ Group B & 728.1 \(\pm\) 18.573 & 2265.8 \(\pm\) 90.553 \\ Group C & 2654.8 \(\pm\) 115.424 & 5670.4 \(\pm\) 838.353 \\ Group D & 2005.3 \(\pm\) 315.436 & 3542.7 \(\pm\) 181.132 \\ \hline \multicolumn{3}{c}{**Tukey HSD Post Hoc Test**} \\ \hline
**Treatment Pair** & **Q Statistic** & \(p\)**-Value** & **Tukey HSD** \\ \hline A to B & 2.5587 & 0.2858986 & insignificant \\ A to C & 21.9313 & 0.0010053 & \({}^{**}\)\(p\)\(<\) 0.01 \\ A to D & 7.7999 & 0.0010053 & \({}^{**}\)\(p\)\(<\) 0.01 \\ B to C & 24.4899 & 0.0010053 & \({}^{**}\)\(p\)\(<\) 0.01 \\ B to D & 10.3585 & 0.0010053 & \({}^{**}\)\(p\)\(<\) 0.01 \\ \hline \hline \end{tabular}  
* The result is significant at \(p\)\(<\) 0.05.  
\end{table} 
Table 1: Mean values and standard deviations (SDs) for compressive strength test (cracking stage and destruction stage) and pairwise comparisons between group means.