## 1 Introduction  
The marginal bone loss (MBL) of implants is one criterion used to determine the success rate of rehabilitation [1]. A reduction in MBL can reduce other complications, such as soft tissue recession, peri-implantitis, fractures and implant loss. Historically, MBL from 1.2 mm to 2.0 mm is reported during the first year of function, with a further loss of 0.1 mm every year, with the greatest bone loss occurring during the first three months of occlusal loading [2]. Studies demonstrate that implants with a Morse taper connection can preserve the bone even after second-stage surgery and initial loading [3, 4]. Recent implant systems, with one to five-year follow-ups reveal MBLs smaller than historically acceptable, as follows: 0.2 \(\pm\) 1.2 mm after one year with Morse taper [5]; 0.42 \(\pm\) 0.77 mm after three years with Morse taper [4]; and 0.47 \(\pm\) 0.65 mm with external hexagon and 0.15 \(\pm\) 0.33 mm with internal hexagon, after four years.  
Osseintegration has been defined as a direct and functional connection between the bone and an artificial implant. Both bone quality and quantity can influence the success of these procedures [6]. Height and density are two important parameters for a successful result in implantology. Bone compaction and the osseedensification technique positively affect the primary implant stability values in cancellous bone, which permitsa high insertion torque [7]. Insertion torque is the force required for the implant to lock in the bone structure, expressed in newton centimeters (Ncm) [8]. The optimal torque value depends on the manufacturer's recommendations, but it is usually between 30 and 40 Ncm [9], and the higher the insertion torque, the greater the tension in the region. This may be associated with peri-implant bone injury and difficulties in vascularization, contributing to osteocyte necrosis, and resulting in microfractures in the cortical bone, extensive bone remodeling and minimal bone formation [10].  
According to some theories [1,11], the absence of the functional load on the implants during the healing period represented a fundamental factor for the bone formation. It has been established that a healing period with no functional load on the mandible for three to four months or on the maxilla for five to six months is necessary for osseointegration. However, studies report a high success rate of implants with early and immediate loading, with no difference in the success rate and MBL compared with conventional loading [12,13].  
Diabetic patients show a trend for higher MBL. Chronic hyperglycemia can act on osteoblast synthesis and stimulate osteoclast function [14], reducing bone formation during the healing phase, which explains the higher failure rate during osseointegration.  
Pre-prosthetic MBL has been previously evaluated [5,15], but the factors that influence early MBL (pre- prosthetic) are not often mentioned. The objective of the study is to evaluate the relationship of early MBL around implants with (a) installation torque, (b) time between surgery and reopening, (c) general health (hypertension, diabetes and antihypertensive use), (d) sociodemographic factors (age and sex) and (e) the implant location (maximla or mandibular, anterior or posterior). The hypotheses tested are as follows: (1) early MBL occurs, (2) torques above 40 Ncm generate higher MBL compared with regular torques, (3) systemic and exogenous factors influence MBL, and (4) the location of the implant affects MBL.