## 4 Discussion  
This systematic review and meta-analysis was conducted to evaluate the performance of multiple root coverage by comparing mean root coverage, probing depth, and width of keratinized tissue between collagen matrix and subepithelial connective tissue. The findings of the present study revealed that disparities were seen between collagen matrix and subepithelial connective tissue with respect to root coverage and width of keratinized tissue. In general, subepithelial connective tissue exhibited more favorable results. Gingival recession is generally characterized by the displacement of the gingival margin apical to the cementoenamel junction, resulting in the loss of periodontal connective \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Variables**} & \multicolumn{2}{c}{**Original Analysis**} & \multicolumn{2}{c}{**Trim-and-Fill Analysis**} & \multicolumn{1}{c}{**Egger’s Regression Test**} \\ \cline{2-5}  & **SMD/RR (95\% CI)** & **SMD/RR (95\% CI)** & **Added Studies/Total Studies** & \(p\)**-Value** \\ \hline MRC & \(-0.48\) (\(-0.69\) to \(-0.26\)) & \(-0.48\) (\(-0.69\) to \(-0.26\)) & \(0/9\) & \(0.81\) \\ CRC & \(0.68\) (\(0.49\) to \(0.94\)) & \(0.88\) (\(0.56\) to \(1.38\)) & \(3/11\) & \(0.02\) \\ KTW & \(-0.75\) (\(-1.25\) to \(-0.26\)) & \(-0.58\) (\(-1.15\) to \(-0.01\)) & \(1/9\) & \(0.10\) \\ PD & \(-0.27\) (\(-0.65\) to \(0.11\)) & \(0.13\) (\(-0.35\) to \(0.60\)) & \(3/9\) & \(0.01\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Analysis for publication bias. tissue fibers along the root cement and the subsequent loss of alveolar bone. The classification system developed by [PERSON] categorizes gingival recession based on its relationship to the mucogingival junction and the extent of soft/hard tissue loss in the interproximal area [28]. There are four distinct types in this classification [28]. In [PERSON]'s Class I, marginal tissue recession does not extend to the mucogingival junction and is not accompanied by alveolar bone loss in the interdental area. Class II is characterized by marginal tissue recession that extends to or beyond the mucogingival junction. Class III involves marginal tissue recession that extends to or beyond the mucogingival junction, along with alveolar bone loss in the interdental area. Class IV is distinguished by marginal tissue recession that extends to or beyond the mucogingival junction and is accompanied by gross alveolar bone loss in the interdental area. In general, it has been reported that complete root coverage can be achieved in both Class I and Class II cases [30]. In a more recent report, the achievement of complete root coverage in Miller class III recessions was shown to be possible through surgical approaches; however, the long-term stability of such outcomes cannot be predicted with certainty [31; 32]. Recession type 1 is defined as the gingival recession with no loss of interproximal attachment and in this case, the interproximal cemento-enamel junction was clinically not detectable at both mesial and distal aspects of the tooth [29]. In this study, most of the recessions were either Miller class I or II or recession type 1 [29]. Subepithelial connective tissue grafts are widely regarded as the optimal solution for achieving root coverage due to their high predictability and excellent esthetic outcomes [33]. Subepithelial connective tissue grafts exhibit excellent tissue compatibility and facilitate the regeneration of periodontal tissues, resulting in stable, long-lasting coverage of exposed roots [34]. The use of subepithelial connective tissue grafts can be more technically challenging and time-consuming due to the requirement of harvesting tissue from the palate [35]. The outcomes of employing collagen matrix versus connective tissue graft for root coverage in gingival recession did not reveal substantial variations in vascular flow [36].