## 2 Materials and Methods
### Histological Processing: Non-Decalcified Bone Samples Embedded in Plastic  
The bone samples obtained following the slaughter of the experimental animals were preserved in formalin for fixation and conservation. Since these bone samples were non-decalcified, they were washed in water and sawn to macroscopically delimit the study areas. The samples were then dehydrated by immersion in ethanol solutions of increasing concentration (70\({}^{\circ}\), 80\({}^{\circ}\), 90\({}^{\circ}\), and 95\({}^{\circ}\)), soaking for 24 h in each solution until reaching absolute ethanol, where they remained for 2 days. The samples were then placed for 15 days under agitation in liquid polymethyl metacrilate (PMMA) at 4 \({}^{\circ}\)C. After 15 days of immersion, the bone samples were transferred to glass cylinders with a base of solid PMMA and filled with liquid PMMA. The tubes were sealed with parafilm and kept in an oven at 32 \({}^{\circ}\)C for 5-6 until polymerization. The polymerized block with the bone sample was then cut with a microtome (Microm HM 350 S). The first sections were made with a thickness of 30 \(\upmu\)m until reaching the study area, where 5 \(\upmu\)m sections were cut and placed on gelatinized slides, covered with polyethylene film and pressed and dried at 60 \({}^{\circ}\)C for 24 h.  
For histological staining, the sections were deplasticized by immersion in methyl acetate for 55 min, then washed in decreasing alcohol solutions until distilled water. The stain used was Goldner's Trichrome, which allows osteoid to be distinguished from calcified bone, as well as the study of the morphology and distribution of cells in the tissues. Microscopic images of histological samples were captured using a Nikon Digital Sight DS-smc camera coupled to a Nikon Eclipse 90i optical microscope. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Sinus**} & **Sinus Wall** & \multicolumn{2}{c}{**Elevation**} & \multicolumn{2}{c}{**Membrane**} & \multicolumn{2}{c}{**Membrane**} & \multicolumn{2}{c}{**Elevation of**} \\  & **Thickness** & **Height** & **Perforated** & **during** & **Perforated** & **All Layers. ** \\  & **(mm)** & **Measured with** & **CBCT (mm)** & **during** & **during** & **during** & **Histological** \\  
Figure 2: (**a**) Distribution of the mean elevation height with the CBCT (mm) in the maxillary sinus floor thickness groups. (**b**) Osteotomy, elevated mucosa 100 \(\upmu\)m. (**c**) Elevation start zone 100 \(\upmu\)m. (**d**) Periosteum 100 \(\upmu\)m.  
In 100% of cases, perforations do not occur during aperture or in the elevation of the wall. There was histological elevation in all layers in 53.33% of the \(>\)10.63 mm height group compared to 46.67% of the \(<\)10.63 mm height group (\(p\) = 1.0000); there was no elevation in 86.67% of the \(>\)10.63 mm height group compared to 13.33% in the \(<\)10.63 mm height group. In the global sample, there was histological elevation in 73.33% compared to 26.66% non-elevation (\(p\) = 0.0268) (see Table 3, Figure 3a,b). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \multicolumn{4}{c}{**Global Sample**} \\ \hline
**Variables** & \(n\) & \% & _p-Value_ \\ \hline Membrane perforated & & 15 & 100.00 & \\ during aperture (no) & & 15 & 100.00 & \\ \hline Membrane perforated & & 15 & 100.00 & \\ during elevation (no) & & & & \\ \hline Elevation of all layers. & & 4 & 26.66 & \\ Histological analysis (no) & & & & 0.0268 \\ \hline Elevation of all layers. & & 11 & & 73.33 & \\ \hline \multicolumn{1}{c}{} & & & & \\ \hline \multicolumn{1}{c}{} & & & & \\ \hline \multicolumn{1}{c}{} & & & & \\ \hline \multicolumn{1}{c}{} & & & & \\ \hline \multicolumn{1}{c}{} & & & & \\ \hline \multicolumn{1}{c}{} & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Distribution and comparison of membrane perforation and histology within groups for maxillary membrane height and global sample. Figure 3: _Cont_. Microscopic images of the histological samples did not reveal ruptures or laceration of the membranes in any of the samples.