## 1 Introduction  
The implant-prosthetic treatment of partially edentulous patients has become in last 20 years a routine treatment procedure with reliable functional and esthetic results. Despite the evolution of implant dentistry, severely resorbed posterior mandible, due to periodontal disease or natural atrophy, remains a challenge even for experienced clinicians. A functional and stable mandibular implant-prosthetic restoration in posterior area can be compromised in the long term due to shape and orientation of the residual alveolar bone, improper sagittal intermaximillary relationships as well as the presence of mandibular inferior nerves. These clinical situations require the enhancement of the alveolar bone volume and quality for long-term success of the implant-prosthetic therapy. However, the high density and low vascularization of the mandibular cortical bone can hinder an effective grafting on the mandible body or regeneration processes of some bone chambers [1]. A various range of bone regenerative bone have been proposed to create conditions for long term success of the implant-prosthetic restorations in mandible posterior areas (guided bone regeneration (GBR), distraction osteogenesis, alveolar ridge splitting techniques, bone expansion techniques, bone grafting techniques) [2; 3]. Every surgical technique has advantages and disadvantages, but specialists should give priority to those procedures which are easy-to-use (according to the practical experience of the clinician), less invasive, have lower risk of complications, and allow osteointegration of dental implants within the shortest post-operatory time [4]. Data are controversial regarding the success rate on medium and long term due to low quality of methodology (poor sample size, undefined success criteria, short-term follow-up) [4]. A scientifically validated opinion on which is the best technique and grafting materials is hard to obtain, especially in posterior mandible area. Due to vertical and horizontal bone resorption, augmentation procedures require a minimal surgical technique aiming to avoid soft tissue dehiscence above the bone regeneration compartment. The use of minimally invasive tunneling technique in the reconstruction of horizontally bone defects is associated with difficulty in the positioning and maintenance of the grafted bone in coronal position to increase the area of the peri-implant soft tissues [5]. The success of the lateral ridge augmentation depends on the experience of operator and by ability to stabilize and maintain the graft at the alveolar crest. In large alveolar defects the maintaining of the stability of the grafted areas becomes even more difficult when using this technique [5]. The success of GBR techniques is more predictable when used to patients with mild to moderate horizontal alveolar bone resorption and small edentulous span that allows simultaneous placement of implants. Variants of GBR techniques that use tenting mechanisms can prevent collapse of the soft tissues and bone resorption [5]. Considering these issues, we focused our research on a particular technique used in our dental practice that allows us to obtain excellent results for mandibular edentulous patients with mild-to-moderate atrophy of alveolar bone [6; 7]. Screw-guided bone regeneration (S-GBR) is a technique derived from GBR that uses a membrane that delimitates the regenerative bone compartment supported by osteosynthesis screws or dental implants [7]. S-GBR is mostly recommended to the lateral augmentation of the mandibular alveolar bone with moderate or severe horizontal resorption, by using a combination of autograft, xenograft, resorbable or non-resorbable membranes. The significant difference between S-GBR technique and other techniques used in the horizontal augmentation of the alveolar crest is the system used for the maintenance of the regenerative bone space (osteosynthesis screws as space holders, pericardium membrane to protect the graft material from soft tissue invasion), with lower rate of complications.