# Effects of Surgically Assisted Rapid Palatal Expansion on Facial Soft Tissues: A Systematic Review
## 3 Results
### Study Characteristics  
Out of the 15 studies, 1 was a randomized clinical trial [17], 2 were prospective non-randomized controlled clinical trials [18; 19], 8 were retrospective cohorts [28; 29; 30; 20; 21; 22; 20; 22; 23; 24; 25; 26; 27], and 5 were uncontrolled studies [23; 24; 25; 26; 27] (specifically 1 retrospective before-after study [23], 2 prospective studies with a repeated measures design [24; 25], and 2 retrospective studies with a repeated measures design [26; 27]). Study design, eligibility criteria, and sample characteristics of the included studies have been uploaded separately as supplementary files (Supplementary Table S1). Seven studies included pterygomaxillary disjunction in their surgical technique [17; 18; 19; 23; 25; 28; 31], while remaining seven studies did not [20; 21; 22; 24; 27; 29; 30]. [PERSON] et al. did not clarify whether this procedure was included in the surgical technique [26]. Four studies applied alar cinch sutures [17; 23; 26; 31], five studies applied alar base V-Y sutures [17; 20; 23; 26; 27], one study applied both alar cinch and alar base V-Y sutures [21], two studies applied neither alar cinch nor alar base V-Y sutures [24; 25], while the remaining studies did not clarify whether they included these techniques in the surgery. Eight studies used a tooth-borne expander [21; 22; 23; 24; 25; 26; 27; 28; 30], three used a bone-anchored appliance [25; 28; 31], three used both [18; 19; 20], and one was unclear in relation to the expander [17]. Seven studies included a comparator [17; 18; 19; 20; 21; 22; 31]. Two studies compared SARPE with rapid maxillary expansion (RME) [21; 22], one compared SARPE with miniscrew-Assisted rapid palatal expansion (MARPE) [31], one compared different sutures within the framework of SARPE [17], one compared two dissection tools [17], and four studies compared two types of expanders (again, within the framework of SARPE) [18; 19; 20; 21]. The details of the undertaken orthog  
Figure 1: PRISMA study flow diagram. nathic procedures, the expander, and the expansion protocols as well as the comparison groups have been uploaded separately as supplementary files (Supplementary Table S2). As far as the study outcomes are concerned, three studies included nasal measurements [26; 27; 30], four included nasolabial measurements [20; 21; 22; 23; 24], one included labial measurements [17], five studies included various facial measurements [18; 19; 22; 25; 28] and two studies included various nasal and soft tissue measurements [29; 31]. The evaluation of the changes was two dimensional in six studies [17; 21; 22; 26; 27; 29] and three dimensional in nine studies [18; 19; 20; 23; 24; 25; 30; 31]. The outcomes were measured clinically with a caliper in two studies [26; 27], via laser scan in one study [25], via three-dimensional photogrammetry in three studies [19; 23; 28], via lateral cephalometric analysis in one study [21], via calibrated two-dimensional photography in one study [22], via CBCT in five studies [20; 24; 29; 30; 31], and via a combination of lateral cephalometric analysis and clinical evaluation with a caliper in two studies [17; 19]. All studies included measurements before intervention. Post-SARPE soft-tissue evaluations were carried out at 2 months in three studies [24; 25; 31], at 6 months in seven studies [17; 23; 25; 26; 27; 29], at 12 months in two studies [25; 26], and at 24 as well at 36 months in one study [27]. Three CBCT studies re-evaluated the patients after 18 [24] or 22 months [18; 19]. One study measured the outcomes at specific stages of orthodontic treatment [22]. One study had a minimum of 6 months follow up [20] and three studies did not specify the time of re-evaluation [21; 28; 30]. The details of the studies' outcomes, outcome measures, and time of measuring are presented in Table 3.