## 3 Results
The maximum temperature was lower in the zirconia group compared to the lithium disilicate group; however, there was only statistical difference in the third retrieval experiment (\(t\)-test, \(p=0.18\), \(p=0.34\), and \(p=0.003\) for first, second, and third retrieval, respectively). Changes in abutment surface area and cement gap as a result of additional tooth preparation prior to the third crown retrieval experiment are summarized in Table 3. The abutment surface area played an important role in the retrieval time in all cases (r = 0.67 to r = 0.86). In terms of retrieval time, both materials demonstrated similar correlations. The larger surface area was positively correlated to the longer retrieval time. The cement gap played little to no role in the zirconia group (r = 0.2), while in the lithium disilicate group, the larger cement gap correlated with the faster retrieval time (r = \(-\)0.43). In terms of temperature, the two materials behaved in the opposite direction with the weaker correlation compared to the retrieval time. Increasing the abutment surface reduced the temperature in the lithium disilicate group (r = \(-\)0.45 and r = \(-\)0.48), but the opposite was seen in the zirconia group (r = 0.56 and r = 0.69). The width of the cement gap had almost no role in the lithium disilicate group (r = 0.2), while the increased cement gap weakly increased the temperature in the zirconia group (r = 0.38). Visual examination of the crown and abutment tooth showed minor cement ablation and no visual cracks or damage to the material or tooth. The SEM analysis was made for one sample from each material group after each treatment (Figures 3 and 4). In the lithium disilicate and zirconia samples from all three experiments, some remaining cement particles were noted, however no noticeable surface damage, microcracks, or any other change was visible on the surface of teeth and crowns. Note that an additional lithium disilicate specimen was added and irradiated based on a published protocol proposed previously as the control [22]. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Sample, Grouping,** & **Abutment** & **Abutment** & **Cement Gap** & **Abutment** & **Abutment** & **Absutment** & **Cement Gap** \\
**and Surface** & **Surface LD1** & **Surface LD3** & **LD3** & **Surface Z1** & **Surface Z3** & **Z3** \\
**Area/Cement Gap** & **(mm\({}^{3}\))** & **(mm\({}^{3}\))** & **(\(\mu\))** & **(mm\({}^{3}\))** & **(mm\({}^{3}\))** & **(mm\({}^{3}\))** & **(\(\mu\)m)** \\ \hline
1 & 127.67 & 119.75 & 394 & 133.81 & 125.69 & 504 \\ \hline
2 & 179.7 & 164.02 & 297 & 150.22 & 125.03 & 210 \\ \hline
3 & 152.55 & 122.87 & 360 & 138.57 & 124.54 & 359 \\ \hline
4 & 141 & 133.89 & 362 & 136.36 & 120.96 & 282 \\ \hline
5 & 226.38 & 209.80 & 277 & 182.76 & 160.93 & 251 \\ \hline
6 & 161.14 & 146.33 & 251 & 150.72 & 133.90 & 301 \\ \hline
7 & 218.57 & 209.31 & 335 & 193.97 & 173.70 & 291 \\ \hline
8 & 130.92 & 117.32 & 385 & 171.32 & 149.56 & 331 \\ \hline
9 & 131.21 & 121.22 & 407 & 136.45 & 122.48 & 302 \\ \hline
10 & 173.66 & 155.30 & 317 & 202.87 & 186.48 & 366 \\ \hline
**Average** & 164.28 & 149.98 & 338.5 & 159.705 & 142.33 & 319.7 \\ \hline
**SD** & 35.54 & 35.18 & 52.26 & 25.99 & 23.91 & 79.89 \\ \hline
**Pearson Correlation** & & & & & & \\ \hline
**Each Factor and Retrieval Time** & 0.84 & 0.74 & \(-\)0.43 & 0.86 & 0.67 & 0.20 \\ \hline
**Each Factor and Retrieval Temperature** & \(-\)0.45 & \(-\)0.48 & 0.20 & 0.56 & 0.69 & \(-\)0.38 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Effects of tooth modification on retrieval times and temperature.