# The Impact of Orthodontic Treatment on Pre-Existing Gingival Recessions: A Retrospective Study
## 3 Results
### Gingival Recession Change at Tooth Level  
718 teeth mesial to molars in 37 patients were evaluated before and after OT; of these, 114 (15.9%) teeth had GR on the vestibular surfaces. Most of the GRs were Miller class I (n = 110) and only four teeth with Miller class II. The distribution of GRs before OT in different groups of teeth is presented in Figure 6.  
Figure 6: Distribution of pre-treatment gingival recessions in different groups of teeth. The median GR improvement was 0.55 mm (Q1, Q3: 0.12, 0.96) (\(p\) = 0.001), with 58.7% (n = 67) gingival recessions improved. From those 67 gingival recessions that improved (the cut-off value defining improvement or worsening was established at 0.5 mm) 25 improved by \(\geq\)1.0 mm. Complete resolution of GR was observed in 15 teeth out of 67 that improved (22.4%) (Figure 7a-c and g-j). GR did not change in n = 41 (36%), and worsened in n = 6 (5.3%) teeth. None of Miller class II gingival recessions healed. Numbers and different groups of teeth with GR change is presented in Table 2. The percentage of improved GR was highest on maxillary canines (84.6%); however, the highest amount of GR improvement in millimetres was observed on maxillary and mandibular premolars (\(p<0.001\)). Healing of GR was mostly ob-served on maxillary incisors (46.7%). No recession was completely healed on mandibular incisors. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Tooth Group**} & \multicolumn{4}{c}{**Change of Gingival Recession**} \\ \cline{2-5}  & **Improved n (\%)** & **No Change n (\%)** & **Became Worse n (\%)** & **Total n (100\%)** \\ \hline Maximillary incisors & 10 (62.5) & 5 (31.3) & 1 (6.3) & 16 \\ \hline Maximillary canines & 11 (84.6) & 2 (15.4) & 0 (0.0) & 13 \\ \hline Maximillary premolars & 16 (53.3) & 13 (43.3) & 1 (3.3) & 30 \\ \hline Mandibular incisors & 7 (58.3) & 5 (41.7) & 0 (0.0) & 12 \\ \hline Mandibular canines & 10 (52.6) & 8 (42.1) & 1 (5.3) & 19 \\ \hline Mandibular premolars & 13 (54.2) & 8 (33.3) & 3 (12.5) & 24 \\ \hline Total & 67 (58.8) & 41 (36.0) & 6 (5.3) & 114 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Change of gingival recession in different groups of teeth. Figure 7: (a–c)—change of gingival recession when deep traumatic contact of tooth 23 was corrected by intrusion; (d–f)—no significant change of gingival recession of tooth 23 before, during and after orthodontic treatment; (g–j)—change of gingival recessions before and after orthodontic treatment of maxillary and mandibular anterior teeth due to more favorable centered position in the middle of alveolar bone. The percentage of improved GR was highest on maxillary amines (84.6%); however, the highest amount of GR improvement in millimeters was observed on maxillary and mandibular premolars (_p_ < 0.001). Healing of GR was mostly observed on maxillary incisors (46.7%). No recession was completely healed on mandibular incisors. Median GR change after OT at tooth level in relation to different pre-treatment factors could be seen in Table 3.  
The percentage of improved GR was highest on maxillary amines (84.6%); however, the highest amount of GR improvement in millimeters was observed on maxillary and mandibular premolars (_p_ < 0.001). Healing of GR was mostly observed on maxillary incisors (46.7%). No recession was completely healed on mandibular incisors. Median GR change after OT at tooth level in relation to different pre-treatment factors could be seen in Table 3.