## 2 Materials and Methods
The product was then transferred to a dark glass bottle and stored in a freezer at a temperature of \(-20\)\({}^{\circ}\)C.  
Infiltration: One gram of Hardener 1 was added to 250 mL destabilized MMA and mixed for 1 h using a magnetic stirrer. Then, 20 g of PMMA (powder) was added gradually to the mixture. Each portion was added after the complete dissolution of the previous one, i.e., after a clear solution was obtained. Complete dissolution of the powder took approximately 2 h. The product was transferred to a dark glass bottle and stored in a freezer at a temperature of \(-20\)\({}^{\circ}\)C.  
Stock solution A: Eighty grams of PMMA were added gradually to 400 mL destabilized basic solution in a graduated glass beaker. Each portion was added after the complete dissolution of the previous one, i.e., after a clear solution was formed. Complete dissolution of the powder took approximately 6 h. Then, 3 g of Hardener 1 was added to the solution, and it was stirred for another hour. A destabilized basic solution was added to the 500 mL beaker mark and stirred for 30 min. The product was transferred to a dark glass bottle and stored in a freezer at a temperature of \(-20\)\({}^{\circ}\)C.  
Stock solution B: Thirty milliliters of the destabilized basic solution was added to 4 mL of Hardener 2 and stirred for 1 h in a graduated glass beaker. Then, 2 mL of the regulator was added to the solution and stirred for 30 min. The beaker was filled up to the 50 mL mark with the destabilized basic solution, and the mixture was stirred for another 30 min. The final product was transferred to a dark glass bottle and stored in a freezer at a temperature of \(-20\)\({}^{\circ}\)C.  
Polymerization solution: After cooling, Stock Solutions A and B were mixed in a 9:1 ratio in a glass beaker. The mixture was stirred gently for 1 min, and then it was ready for immediate use. **Polymerization:**  
Part of the polymerization mixture was poured into pre-cooled polyethylene embedding models. The infiltrated tissues were then placed in the molds using plastic tweezers and covered with the polymerization solution. The loaded embedding molds were transferred to a pre-cooled desictor (at 4 \({}^{\circ}\)C). Oxygen was withdrawn from the desiccator via rough vacuum (200 mBar, for 10 min) and, thus, the air bubbles formed during the pouring were evacuated. The filled molds were closed and pressed using a dental flask clamp, and placed in a freezer at a temperature of \(-20\)\({}^{\circ}\)C. After 3 days, the samples were put in a refrigerator (4 \({}^{\circ}\)C) for 24 h. The following day, the molds were placed at room temperature for another 24 h before they were opened. **Sectioning:**  
Sectioning the samples at an appropriate thickness is essential for optimal light transmission. Sometimes the bone histology of specimens containing dental and orthopedic implants requires unconventional section thickness. The hard MMA blocks containing the tissue were placed under a laboratory fume hood overnight for evaporation of the residual monomer. Then, the blocks were sectioned down to approximately 800 \(\upmu\)m using a precision sectioning saw (Isomet 1000, Buehler Ltd., Lake Bluff, IL, USA). Sections were glued to acrylic microscope slides (Exakt, Norderstedt, Germany) using UV glue Technovit 7210 VLC (Technovit7210 VLC, Heraeus Kulzer, Germany). The sections were then reduced in thickness to 20-40 \(\upmu\)m on a grinder/polisher (EcoMet30, Buehler, Leinfelden-Echterdingen, Germany) using Silicone Carbide abrasive papers (with grit sizes P400, P800, P1200, P1500) (CarbiMet, Buehler Ltd., Alzenau, Germany) and 0.05 \(\upmu\)m polishing suspension (MasterPrep, Buehler Ltd., Germany). **Toluidine blue staining:**  
The samples thus prepared were divided into eight groups. There were a total of 120 samples--15 samples per group. The first group was stained with toluidine blue (Diapath, Italy) according to a protocol introduced by [PERSON] and [PERSON] (2005) for staining cement lines [30] (Table 2).