## 2 Materials and Methods  
The present pilot study was approved by the Ethics Committee of the School of Medicine and Surgery at the Milano Bicocca University, (protocol n. 11/17), and derived from the approval of Italian National Institute of Health (ISS), protocol 30 July 2007-0040488, and it was conducted in accordance with the Declaration of Helsinki. In this study we evaluated implants with rough surfaces, to assess their clinical performance over a period of years. In particular, we considered two types of rough surface:  
* Ti-Unite(tm) implant surface: This surface was introduced in 2000 (Nobel Biocare, Gothenburg, Sweden). It is characterized by a moderately rough thickened titanium oxide layer; the productive process leads to a duplex oxide structure through spark anodization in an electronic solution, that results in an outer barrier with numerous pores (depth between 4 and 10 microns) and an inner barrier layer without pores; moreover, it enhances osteoconduction, with faster anchorage to bone matrix, thanks to its high crystallinity and phosphorus content [25] [Figures 1 and 2]. * Ossean(r) implant surface: Ossean(r) is a moderately rough Ti-Al-V surface obtained through the resorbable blasted medium (RBM) process, followed by the incorporation of a low amount of CaP. Figure 1: TiUnite(tm) implant surface: low-magnification transmission electron micrograph. Reproduced with permission from [26], Copyright Springer, 2015. The surface roughness was designed to obtain micro and nano irregularities, which should enhance implant biocompatibility compared to traditional surfaces, increasing the available contact surface and potentially improving the mineralizing cell attachment and expansion [27] [Figure 3]. The incorporation of a low amount of CaP may improve the surface biointeractivity during the initial osseointegration processes through the apatite nucleation on its surface without the abovementioned detrimental effects; however, no information on the apatite nucleation ability of the implant has been reported [28]. For the selection of implants, we established the following inclusion criteria: both male and female, non-smoking history, absence of allergies, absence of uncontrolled systemic disease, absence of pregnancy or lactation, absence of abuse of alcohol or drugs, and acceptance of the maintenance protocol and laser-assisted treatments proposed. Exclusion criteria were presence of allergies, presence of uncontrolled systemic disease, presence of pregnancy or lactation, abuse of alcohol or drugs, and non-acceptance of the maintenance protocol and laser-assisted treatments by signing an informed consensus. Our sample consisted of 67% male patients and 33% female in the Ti-Unite group of implants; for the Ossean group of implants we selected 45% male patients and 55% female patients. Figure 3: Ossean® implant surface [29]. Figure 2: TiUniteTM implant: dark-field transmission electron micrograph of the depression on the surface. Reproduced with permission from [26], Copyright Springer, 2015. The average mean age of patients that received Ti-Unite implants was 61 years, while the average mean age for Ossean implants was 55 years. In our study we analysed a total of 500 implants for the Ti-Unite surface, and 1000 implants for the Ossean surface. Implants with the Ti-uniteTM surface--273 in the upper arch and 227 in the mandible--had been inserted, for 65% of patients, in regenerated bone (PRF (platelet-rich fibrin), 45%; Bio-Oss(r), 45%; and autogeneous bone, 10%); 179 in the upper arch with regenerated bone and 146 in the mandible with regenerated bone [Table 1]. All implants had a follow-up period of more than 10-years. ([PERSON] 2018). There were a total of 1000 implants with the Ossean(r) surface, 556 in the upper arch and 444 in the mandible. For 63.9% of patients, this type of implant had been inserted in regenerated bone; 351 in the upper arch and 288 in the mandible (Table 1). All implants had a follow-up of more than 10-years. ([PERSON] 2018).