**3. Results**

#### *3.1. Study Selection*

A total of 572 articles were identified in the first phase of the research. During the second phase, 94 articles were considered, and after full-text evaluation 16 studies were included in the review. Finally, five articles of interest were obtained through manual research obtaining a total of 21 articles were included in this review [17–37] (Figure 2).

**Figure 2.** Flow diagram of study inclusion.

#### *3.2. Study Methods and Characteristics*

Four studies were RCT [20,24,33,35], 2 were NRCT [21,28], 2 were prospective studies [22,32] and 13 were case series [17–19,23,25–27,29–31,34,36,37] and all of them were published between 2001 and 2021 (Table 1).

The studies were conducted in nine different countries, the total number of patients included was 382 (137 males, 193 females, and 52 non-specified) and a total of 416 titanium meshes.

There were four articles in which the gender was not specified [20,33–35]. The study with a higher number of patients was Miyamoto et al. (N = 41) [17] while the one with fewer patients was Ciocca et al. [29] with a total of nine patients. The mean age was 53.4 and four articles did not specify the mean age [24,27,34,35].

Regarding the characteristics of the surgeries performed, it was quantified the number of sites, and whether if it was in mandible or maxilla. In five studies, the number of sites was not specified [18,28,30,34,35], of which 164 sites belong to the maxilla and 129 to the mandible.

In 16 studies the graft material used was autologous bone; in six of them it was the only material used [17,18,20,21,23,28] (N = 120), and in the other 10 articles, autologous bone was associated with other graft materials such as inorganic bovine bone (ABB) [19,22,25,26,32,35,37] (N = 91), thermoplastic mouldable allograft paste (TMAP) [33] (N = 28), bovine porous bone protein (BPBM) [21] (N = 3), demineralized bovine bone mineral (DBBM) [27] (N = 13) or Hydroxyapatite [29] (N = 21). There were five studies in which autologous bone was not used and the regeneration was performed only with the use of ABB [24,30,34] (N = 67) or TMAP (36,31) (N = 39).

The removal of the mesh and the quantification of bone gains was performed during the second-stage surgery or also called in most studies as healing period, which was performed on average at 6.5 months.

#### *3.3. Quality Assessment and Risk of Bias within Studies*

The risk of bias of the RCT is presented in Table 2. Three RTCs were considered as having a low risk of bias even though there were some concerns about the blinding of participants and researchers [24,33,35] and Atef et al. did not report the blinding of outcome assessment and selective outcome reporting, potentially introducing selection bias [35]. One study was considered as having a high risk of bias since there were some concerns about the random sequence generation, the allocation concealment, and the blinding of participants and researchers [20].


**Table 2.** Risk of Bias of included randomized clinical trials.

L: Low; (?): Unclear; H: High.

Two non-randomized clinical trials were included, and the risk of bias is represented in Table 3. These two articles were considered as having a low risk of bias but there were some concerns about potential bias in the classification of interventions [21,28] and also due to deviations from intended interventions [21].

**Table 3.** Risk of Bias of included non-randomized clinical trials.


L: Low; (?): Unclear; H: High.

(The systematic review was reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) scale [13]) with 21 items.

*3.4. Characteristics of the Mesh*

Different types of meshes were used in the studies, all of them are summarized in Table 4.

**Table 4.** Characteristics of the meshes used.


NE: Not evaluated.
