## 3 Results and Discussion
### Initially Proposed Protocols (2014-2015)
#### 3.4.1 Exposed Neck Protocol  
Several research groups proposed the supracestal positioning of the implant neck, with partial exposition of the neck above the tissue levels, supported by case reports [43,44] and clinical studies [29, 30, 31, 32] and also considering multiple insertion and an immediate protocol [45]. The neck exposition for approximately 1.0 mm (and the flapless procedure) avoided the use of a second surgery to expose the neck. No healing screws have been used in accordance with the initial protocol. A preliminary study was dedicated to the anterior rehabilitation of elderly patients partially affected by periodontal disease [46]. The implants were placed with the flapless technique, and the implant neck profile (i.e., implant neck with 1.0 mm cover screw) was left exposed for 1.0-1.5 mm, and prosthetic phases were performed after 3 months and a cemented provisional, followed by a definitive crown, was fixed on customized abutments with no proper finishing line. By performing such a minimally invasive rehabilitation protocol, the use of a Prama implant was proposed for elderly patients [46] to reduce discomfort and rehabilitation time. To support the use of the neck position being exposed, a recent histological study demonstrated effectively that Prama implants placed subrestally showed greater bone loss and were afflicted with greater soft tissue recessions [9]. In agreement with this, a recent randomized 1-year clinical trial reported markedly higher MBL stability when convergent neck implants were placed with a non-submerged approach in comparison to platform switch submerged implants [21]. Both implants have different neck morphologies but the same surface texture, so they were rather comparable. Altogether, the 1-3 year MBL ranged from 0.12 mm to 0.44 mm [8,29, 30, 31, 32]. Interestingly, only marked MBL variations were observed after 6 years of loading; the MBL was 0.91 mm [17]. The study demonstrated that the exposed/transmucosal protocol is particularly useful when in the presence of aging patients, thus requiring only limited and low-invasiveness interventions. The elderly population (>65 years) is a widespread patient population that may benefit due to the presence of systemic diseases (cardiovascular disease, diabetes mel  
Figure 1: Minimally invasive protocol performed in 2014-2015. Implant insertion in different scenarios. (**a**) Implant positioned with neck partially exposed (transmucosal insertion technique); (**b**) in post-extractive areas; (**c**) in healed crests. Note the different neck heights, decided on the basis of the soft tissue thickness. litus, osteoporosis, rheumatic diseases, and poor nutrition), which could lead to worse oral health conditions, including aggressive dental decay and periodontal compromission [47]. In this way, it was possible to restore single dentulism in the esthetic areas without complex and invasive surgeries. Moreover, the transmucosal exposition of the neck can be tailored according to the clinical scenario (Figure 1). The concept of placing the implant with the neck exposed at the tissue level implies that the neck is just exposed and positioned approximately at the papilla level, with a \"half-moon\" gingival exposure. The larger part of the neck profile is situated just beneath the gingival contour, making it not visible but detectable with a probe [29; 30; 31; 32; 33; 346]. No-flap elevation was performed in some cases [17; 32; 46]. In such cases, the implant impression phases after a 3-month healing period were more easily performed as no surgical exposition of the neck was required. In addition, the implant abutment connection was internal to the prosthetic rehabilitation (Figure 2). The implant-abutment connection is described as a critical area susceptible to bacterial contamination [48], tissue inflammation [49; 50], mechanical stress [51], and bone loss [52].