## 4 Materials and Methods  
Four equine spongious bone blocks (10 \(\times\) 20 \(\times\) 5 mm) with collagen (OX Block; Osteoxenon; Biotech; Italy) were divided into 15 samples with a cubic shape (5 \(\times\) 4 \(\times\) 5 mm). To obtain the cubic shape, four osteotomies per sample were performed. A single cutting device was used for each sample. The devices for bone modeling used in this study can be seen in Figure 7.  
* Group A: One stainless steel diamond bur truncated conical shape (ISO diameter 016) Komet (Komet, Lemgo, Germany);* Group B: One round tungsten carbide bur Komet (ISO diameter 018) (Komet, Lemgo, Germany);
* Group C: One stainless steel Lindemann type bur Komet (ISO diameter 016) (Komet, Lemgo, Germany)
* Group D: One Merton OT12S tip mounted on a Piezonsurgery Touch (Mectron, Vicenza, Italy);
* Group E: One Sonosurgery SFS 101 mounted on a Sonosurgery (Komet Dental, Lemgo, Germany). The piezosurgery and sonosurgery tips were used with gentle scratching movements and very little pressure (Table 2). The Diamond bur and Lindemann bur were mounted on a high-speed handpiece (400,000 rpm) (Bien Air, Dental SA; Bienne, Switzerland). The round tungsten carbide was mounted on a low-speed handpiece (20,000-40,000 rpm) (W&H Dentalwer Burmoos GmbH, Bad Hofgastein, Austria). The uncut upper and lower part of the bone block was used as a control (Group F). Four SEM observations were performed for each sample in the test area as well as two observations in the control area. One operator, who was an oral surgeon with more than 10 years of routine practice in oral surgery and the usage of ultrasonic devices, was recruited for the sample creation. The block perimeter was previously marked with a pencil on the surface by using a titanium template. All osteectomies were performed following the manufacturer's instructions, and conducted under irrigation with cooled 0.9% sodium chloride solution. Each device and bur/tip was used in accordance with the manufacturer's recommended settings in order to obtain cuts on bone blocks with the following characteristics:  
* Minimal percentage variance between osteotomic track thickness and tip thickness;
* Osteotomized bone surface as smooth as possible;
* Microarchitecture integrity, limiting the presence of bone debris and avoiding thermal injuries to the bone; and
* Cutting time kept as short as possible. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Device** & **Frequency** & **Insert Tip** & **Thickness** & **Oscillation Amplitude** \\  & **(kHz)** & & **(mm)** & **(mm)** \\ \hline Piezonsurgery Touch & 24 \(<\) x \(<\) 36 & OT12S & 0.25 & 20 \(<\) x \(<\) 60 \\ Sonosurgery & 5 \(<\) x \(<\) 6.5 & SFS101 & 0.25 & 240 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Features of tips as reported by manufacturers. Figure 7: Tips/burs used for osteotomy in groups A, B, C, D, E.  
Samples were divided in groups of three for each bur/tip used. The 15 samples underwent SEM (Phenom Pro 5; Phenom-World B.V.; Eindhoven; Netherlands) observation to directly observe the macroscopical and microscopical structure. Specimen surfaces were analyzed at a 3072 \(\times\) 2304 pixel resolution with a magnification of 500\(\times\)\(\pm\) 50\(\times\)[36]. Within the same area of the sample, observations were conducted by taking random references from three default areas that were 500 \(\upmu\)m\({}^{2}\). Two calibrated observers independently analyzed the images on a high-definition 24-inch screen. The cut surface of each sample was randomly observed in three areas. The observational parameters were recorded following the scheme proposed by [PERSON] et al. as follows:  
* Cut precision (sharpness);
* Depth of incision (depth);
* Peripheral thermal damages (carbonization); and
* Presence of bone debris (bone fragments). For each parameter a score of 0 (very low grade), 1 (low grade), 2 (moderate grade), or 3 (high grade) was given [39]. Numerical data were expressed as means with standard deviation (S.D.)