# The \"Sling\" Technique for Horizontal Guided Bone Regeneration: A Retrospective Case Series
## 4 Discussion  
Tooth loss and consecutive bone resorption depend on local and systemic agents and also involve psychological factors. In the elderly, depression can be more severe due to dedentulous jaws and missing or decayed teeth as well as oral dryness. Therefore, people with depression or other systemic disorders may have impaired oral health [20; 21; 22]. Guided bone regeneration (GBR) is a procedure used with the rationale to increase alveolar bone volume in areas designated for future implant placement or around previously placed implants that were deficient or inadequate. To obtain predictable results, both considerable surgical skills and the full understanding of the biological mechanism that rules this technique are mandatory [23]. In particular, primary wound closures are required to ensure undisturbed (by external bacteria or other external injuries) wound healing as well as angiogenesis (to ensure an adequate blood supply with nutrients and bone growth factors), space maintenance/creation (to allow bone cells to grow and mature whilst excluding the faster proliferation of undesired soft tissues and to guide the bone regeneration into the detected position) and the stability of the wound (to improve the blood clot formation) [23; 24]. Although it is a well-established technique, it is a procedure that is sensitive to the technique used [25; 26; 27; 28]. Several bone regeneration techniques have been described such as using resorbable or non-resorbable barrier membranes [28]. The crucial element for the success of all of them is the achievement of a good vascularization, ensuring blood supply during surgery [26]. To reach this goal, an experienced operator is required. Several steps of these techniques, such as tension-free flap closure and the stability of the graft, need practical skills that can only be acquired after a long learning curve [25]. In addition, numerous post-surgical complications have been described following a GBR procedure, which in most cases can compromise the outcome [10; 29]. A recent systematic review highlighted that the most common post-surgical complication that occurs after GBR surgery is wound dehiscence, with an incidence rate of 9.9% (95% CI 6.4, 13.9, \(p\) < 0.01). This adverse healing results in the early or late exposure of the membrane as well as contamination, infection and the partial or total loss of the graft, with a significant negative effect on bone formation gain [30]. In a recent systematic review, [PERSON] et al. reported an overall membrane exposure rate of 22.7% in simultaneous GBR procedures with no significant difference between resorbable and non-resorbable membranes [29]. These results were also confirmed by another systematic review that showed no differences in post-surgical complications based on the type of membrane used [30]. Figure 17: After 12 days, the area was healing with a secondary intention. With our case series, we aimed to report on an innovative use of the e-PTFE membrane to maximize the performance of the non-resorbable membranes and to reduce the risk of biological complications related to its exposure. Following the application of the PASS principles to perform predictable GBR procedures, one of the key factors is to stabilize the membrane and, consequently, the underlying graft materials [23]. The primary stabilization of the graft materials is mandatory to obtain a successful regenerative procedure because micromotion of the bone particulate can lead to osteogenesis with the encapsulation of fibrous tissue [23]. For this reason, with our \"sling technique\", we maximized the compression of the graft material by stretching the non-resorbable e-PTFE membrane, pulling it from distal to mesial and fixing it with pins. In this way, the stability of blood clots improved; this is a necessary condition to recruit cytokines and growth factors as well as all the cells required to initiate the complex phenomena of bone formation and remodeling.