## 4 Discussion
[11], who observed complete RC in 38% of patients (8/20 patients) after treating Miller class III recessions with the modified tunnel technique combined with an enamel matrix derivative and CTG. While the coverage efficiency was low, the fact that their technique addressed the challenge of Miller class III recessions should be noted. [PERSON] et al. [36] also treated a total of 14 isolated Miller class II and III recessions in mandibular incisors in 10 patients using a coronally advanced flap (CAF) and CTG. At 11.7 months after surgery, the mean RC was 90.22% \(\pm\) 12.36% for all recessions treated. In Miller class II defects, the mean RC was 94.04% \(\pm\) 10.45%, while a complete RC was reached in five (71.42%) out of seven defects. In class III recessions, the mean RC amounted to 86.41% \(\pm\) 13.70% and a complete RC was obtained in three out (42.85%) of seven defects. Statistical analysis revealed no differences between the two groups. In the present study, if we limit the analysis to the results for Miller class III defects, a mean RC of 76.4% \(\pm\) 24.2% was obtained, which is lower than the values reported in the study by [PERSON] and colleagues [36] (around 86%) and higher than the results of the study by [PERSON] et al. [11] (around 40%). A recent systematic review [37] included 18 articles with 399 Miller class I and II isolated gingival recessions that were treated using the CAF technique. In this review, 43 gingival recessions affected mandibular central incisors and 26 affected mandibular lateral incisors; the mean root coverage obtained ranged from 86.28% to 91.04%, and complete root coverage varied from 53.8% to 75%. The high variability in the percentage of complete root coverage may be explained by the challenging anatomical conditions present in the mandibular anterior region. The results obtained with the double lateral sliding bridge flap technique with CTG in Miller class II and III defects are promising for the treatment of isolated and multiple mandibular recessions located in the anterior region. However, it should be noted that the results are highly dependent on a careful selection of patients: in particular, whether heavy smokers are included or not [38], and the level of oral hygiene [6]. Therefore, the importance of prescribing chlorhexidine spray after the operation should be stressed, due to its bactericidal and bacteriostatic properties, as well as its vital role in reducing gingival inflammation and in soft-tissue healing [39]. Recently, [PERSON] et al. [40] performed a randomized clinical trial comparing the outcome of the modified tunnel technique with CTG with and without recombinant human platelet-derived growth factor (rhPDGF-BB) in 24 Miller class I and III mandibular multiple recessions. At 6 months, the mean reduction in recession depth was greater in the test group (2.08 \(\pm\) 0.90 mm) than in the control group (1.83 \(\pm\) 0.93 mm) and the mean RC was 82.6% \(\pm\) 23.69% in the test group and 56.3% \(\pm\) 28.55% in the control group. A mean KTW gain of 0.58 and 0.75 mm was observed for the control and test groups, respectively. In the present study, similar results to those of [PERSON] [40] were observed in terms of recession depth reduction (2.5 mm vs. 2.1 mm in Test and 1.8 mm in the control). Our findings on root coverage were also comparable (80.5% \(\pm\) 23%) to those observed by [PERSON] and colleagues (82.6% \(\pm\) 23.69%) in the test group. This evidence suggests that although plasma improves healing, comparable results can be obtained with the technique described here. To analyze the esthetic results after root coverage surgery, the RES index proposed by [PERSON] et al. [26] was used. In our study, a mean score of 7.4 was observed, which is higher than that observed by [PERSON] et al. [41] (6.8) for the treatment of multiple maxillary and mandibular recessions. After a 6-month follow-up, [PERSON] et al.