## Materials and Methods
### Histological Assessment of Dentine Pulp Complex (DPC) Response  
The stained slides were blindly examined under the light microscope (Nikon E100, Tokyo, Japan) by two trained investigators based on parameters such as pulp tissue disorganization, infiltration of inflammatory cells, bacterial detection, and deposition of tertiary dentin as shown in Table 1.  
Measurements of the remaining dentin thickness (RDT) and the tertiary dentin formation (TDF) were performed for each slide image using ImageJ-J software (Java-based image processing program, Madison, WI, USA). RDT denotes to the thickness of the dentin left after cavity preparation which is between the pulp chamber and the cavity floor (excluding the tertiary dentin which was newly formed). The TDF was considered and calculated as the tertiary dentin thickness which is newly formed after the cavity preparation is performed (between the pulp and the regular dentin). The same parameters for the calculation of RDT and TDF were used for occlusal and cervical types of restorations. An example of RDT and TDF in a rat tooth restoration is shown in Figure 2a. The effects of c-GIC were  
\begin{table}
\begin{tabular}{c l} \hline \hline
**Score** & **Histological Characterization** \\ \hline
**A** & **Pulp tissue disorganization** \\ \hline
**0** & Normal tissue \\ \hline
**1** & Odontoblastic layer disorganized but normal central pulp \\ \hline
**2** & Disorganization of pulp tissue morphology \\ \hline
**3** & Pulp necrosis \\ \hline
**B** & **Inflammatory cell infiltration** \\ \hline
**0** & None or few scattered inflammatory cells present in the pulp area \\  & corresponding to the pulpal/axial wall, characteristic of normal \\  & connective tissue \\ \hline
**1** & Mild inflammatory cell infiltrate with polymorphonuclear (PMNs) or \\  & mononuclear leukocytes (MNLs) \\ \hline
**2** & Moderate inflammatory cell infiltrate involving the coronal pulp \\ \hline
**3** & Severe inflammatory cell infiltrate involving the coronal pulp or \\  & characterizing abscess \\ \hline
**C** & **Bacterial detection** \\ \hline
**0** & Absent or few scattered bacteria next to the area of pulp exposure or newly \\  & formed tertiary dentin \\ \hline
**1** & Presence of bacteria with a clearly visible amount in the coronal pulp \\ \hline
**D** & **Tertiary dentin deposition** \\ \hline
**0** & No or very mild tertiary dentin deposition **(0-49 \(\upmu\)m = Grade 0)** \\ \hline
**1** & Initial tertiary dentin deposition extending to not more than one-half of the \\  & cavity floor **(50–99 \(\upmu\)m = Grade 1)** \\ \hline
**2** & Moderate tertiary dentin deposition extending to more than one-half of the \\  & cavity floor but not completely closing the cavity floor **(100–249 \(\upmu\)m = Grade 2)** \\ \hline
**3** & Intense tertiary dentin deposition, extending entirely along the cavity floor **(250–500 \(\upmu\)m = Grade 3)** \\ \hline \hline \end{tabular}
\end{table}
Table 1: Criteria for scoring of dentin-pulp complex response after occlusal and cervical restorations modified from [PERSON] et al. [27] and [PERSON] et al. [31].  
assessed as a positive control group and TDF in second molars was taken as the negative control. An example of tertiary dentin formation in 2 nd molars is shown in Figure 2b.  
In all rat molars, mild tertiary dentin is usually formed in occlusal and cervical aspects due to the continuous tooth grinding nature of the rats and subsequently mild deposition of tertiary dentin [32]. Hence, we considered Grade 0 as tertiary dentin thickness ranging from 0 to 49 \(\upmu\)m (which was the maximum TDF observed in all 2 nd molars in our study) and considered normal, hence Grades 1, 2, and 3 were considered actual deposition of TDF induced by a particular restoration which was categorized as Grade 1 with 50-99 \(\upmu\)m of TDF, Grade 2 with 100-249 \(\upmu\)m and Grade 3 with 250-500 \(\upmu\)m of TDF as assessed with Image J analysis.