根据移植物的位置，使用改良的冠状先进隧道和上皮下结缔组织移植物治疗多发性牙龈退缩的评估

Procedure: A modified microsurgical tunnel technique. Initial sulcular incisions with a microsurgical blade are followed by a full-thickness buccal flap preparations till muco-gingival junction using the tunneling knives. Subsequently, the split-thickness preparation is extended into the mucosal tissue to gain sufficient flap mobility. The papillary regions are detached in their buccal aspects with the periosteum. The graft is inserted the /inner outer side into the tunnel and stabilized with absorbable suspensory sutures. The buccal flap is advanced coronally and stabilized with non-absorbable suspensory sutures.

21 participants were enrolled into the study, as it was designed to be a split mouth study

Procedure: A modified microsurgical tunnel technique. Initial sulcular incisions with a microsurgical blade are followed by a full-thickness buccal flap preparations till muco-gingival junction using the tunneling knives. Subsequently, the split-thickness preparation is extended into the mucosal tissue to gain sufficient flap mobility. The papillary regions are detached in their buccal aspects with the periosteum. The graft is inserted the /inner outer side into the tunnel and stabilized with absorbable suspensory sutures. The buccal flap is advanced coronally and stabilized with non-absorbable suspensory sutures.

21 participants were enrolled into the study, as it was designed to be a split mouth study.

Mean root coverage (MRC) was calculated as the percent change in gingival recession height from baseline to 6 months using the formula: (GR0 - GR6) / GR0 × 100%.

• GR-gingival recession height: distance between the cementoenamel junction (CEJ) and the gingival margin at the mid-buccal side
• GR0- before surgery
• GR6- 6 months after surgery

The analyzed metrics were calculated as follows:

GR change= GR0-GR6 (after 6 months); ) [millimetre] higher scores mean better outcome GT change = GT6-GT0 (after 6 months); [millimetre] higher scores mean better outcome KTW change = KTW6-KTW0 (after 6 months); [millimetre] higher scores mean better outcome

• GR-gingival recession height: distance between the cementoenamel junction (CEJ) and the gingival margin at the mid-buccal side
• GT- gingival thickness
• KTW- distance between the gingival margin and the muco-gingival junction (MGJ)
• 0- before surgery
• 6- 6 months after surgery

RES:The following variables were assessed:

1. GM - assessment rule: 0 points- root coverage failure, 3 points- partial root coverage, 6 points- complete root coverage;
2. marginal tissue contour (MTC) - assessment rule: 0 points - irregular gingival margin, not in line with the CEJ, 1 point- scalloped gingival contour, in line with the CEJ;
3. soft tissue texture (STT) - assessment rule: 0 points - scar formation, 1 point- absence of scars;
4. MGJ - assessment rule: 0 points - MGJ not aligned with the MGJ of adjacent teeth, 1 point- MGJ aligned with the MGJ of adjacent teeth;
5. gingival color (GC) - assessment rule: 0 points- color does not match adjacent teeth, 1 point- color matches adjacent teeth The maximum score for RES was 10, the minimum 0. Higher scores mean better outcome.