# The Impact of Orthodontic Treatment on Pre-Existing Gingival Recessions: A Retrospective Study
## 4 Discussion
Therefore, lingual movement of the lower incisor crowns, in order to compensate Class III malocclusion, may result in labial movement of incisor roots, thereby causing or worsening GR [32]. Maximally anterior teeth usually undergo proclination due to dentoalveolar compensation in Class III patients, which has also been found to induce the development or worsening of GR [42]. Therefore, the net effect is that Class III patients have a risk of GR worsening during OT. Even if the percentage of worsened GRs in the present study was small (both at patient and tooth levels), it is hard to make conclusions. It is important to know that most of the worsened GRs were in patients with Angle class III dental relationship or reduced pretreatment overbite. No difference in GR change after OT was found between teeth with pretreatment labial tooth position due to crowding, labial/buccal root inclination or unfavorable occlusal contacts with antagonist teeth [12]. Interestingly, GR improvements were somewhat similar despite etiologic factor suggesting that recession improvement may be reached by correction of malocclusion, knowing that the main key is trying to retain the roots within the alveolar bony envelope [28; 44]. The results of the present study reveal that orthodontic tooth movements favoring better position of tooth roots in the alveolar bony envelope by lineually moving labially positioned teeth, or lineually inclining tooth roots (e.g., by selecting appropriate bracket torque), which may increase width of apico-coronal dimension of gingival tissue has to be the primary aim in treating subjects with GRs [2; 21; 22]. Moreover, the use of CBCT, especially in cases with thin periodontal phenotype, has been recommended by American Academy of Periodontology for planning orthodontic tooth movements, especially when labial/buccal movements are needed. As comprehensive orthodontic treatment induces changes in the buccal aspect of alveolar bone, CBCT provides three-dimensional information about alveolar bone thickness and defects and serves for both: planning of orthodontic movements and timing of periodontal augmentation procedures, where needed [45]. It is important to know that orthodontic treatment, especially debonding of fixed appliances, can be linked with a higher sensitivity usually in the anterior teeth, as shown by recent research [46]. The clinical relevance of the present study is that orthodontic movements, together with some related factors, may induce GR change. The results of the present article show the merit of OT in adult patients with pre-treatment GRs. Therefore, confirming the necessity of interdisciplinary collaboration. The tendency of GRs to be improved may be expected in the normal/deep overbite cases, however more in maxillary teeth. However, GRs in open bite and Class III cases, also on mandibular anterior teeth, if present before OT, may need soft tissue augmentation, especially when planning unfavorable camouflage movements in relation to the alveolar bone envelope. This decision is more critical in thin gingival biotype cases [22]. Since 58.8% (n = 67) of GRs improved, and 22.4% (n = 15) of them were completely healed, the null hypothesis was rejected. Limitations of the present study included retrospective design and the measurements performed on plaster models, which were fabricated directly after bracket debonding. The use of plaster models can be problematic as they can be damaged and result in inaccurate measurements, which could influence the results. Also, we can't guarantee that during 12 years exactly the same materials were used for impressions. However, only good quality plaster models were included in the present study and GR measurements were performed with a digital caliper. In a prospective study, we would recommend to wait 3-6 months after OT and perform direct measurements of GR or to perform measurements using digital models [35]. Another limitation is that gingival biotype evaluation was performed on intraoral photographs.