Mucogingival Considerations Following Orthodontic Therapy: A Case Report

Poor oral hygiene, worn or abraded teeth, fibrotic tissues, gingival marginal discrepancies, presence of black triangles, and uneven crown lengths will jeopardize the esthetic appearance of the teeth following therapy. Hence, it becomes imperative to analyze the periodontal tissues prior to initiating orthodontics to avoid adverse effects.

Periodontal tissue inflammation, levels of plaque control, presence of periodontal pockets, status of alveolar bone, and condition of the mucogingival apparatus need to be assessed in detail. Alterations in the mucogingival complex have been seen to occur during orthodontic tooth movement based on two aspects²:

1. modifications in the gingival dimensions and the requirement of a certain gingival thickness for maintenance of the integrity of the periodontium

2. changes in the position of the soft-tissue margins and development of soft-tissue recessions

It is postulated that an adequate amount of attached gingiva is essential for gingival health and to allow appliances to deliver orthodontic treatment without causing bone loss and gingival recession.¹ Isolated gingival recession is one of the most common complications during and after orthodontic therapy.^3-7 Lingual tooth movement results in an increased buccolingual thickness of the tissues at the facial aspect of the tooth, which results in a coronal migration of the soft-tissue margin.^8-10 Conversely, facial tooth movement will result in a reduced buccolingual tissue thickness and, thereby, a reduced height of the free gingival position. The risk for development of recession-type defects in conjunction with orthodontic tooth movement is present only if the tooth has been moved out of the alveolar housing by creating an alveolar dehiscence. The integrity of the periodontium can be maintained during orthodontic therapy also in areas of minimal gingival dimensions by keeping in mind the direction of tooth movement and the buccolingual thickness of the gingiva.

This article illustrates a clinical case in which gingival recession subsequent to orthodontic therapy was seen. A periodontal plastic surgical management technique for the defect is also discussed.

Case Report

A 20-year-old woman reported to the outpatient department (OPD) of the Department of Periodontics at Dr. H.S.J. Institute of Dental Sciences and Hospital, Panjab University, Chandigarh, India in March 2009 with a chief complaint of downward movement of the gums in relation to her lower anterior teeth, which she found esthetically displeasing. Clinical history revealed a long-term orthodontic therapy spanning a period of 4 years. The patient exhibited skeletal Class II normo-divergent deep bite with Angle’s Class II division 1 malocclusion. She had an overjet of 10 mm and an overbite of 90% with proclined upper and normally placed lower incisor teeth with incompetent lips. There was also the presence of an ectopically erupted upper right canine and palatally displaced lower right central incisor.

The patient had undergone all first premolar extractions and had used headgear for the correction of this severe malocclusion. Orthodontics not only helped in achieving a significant improvement in her dental and facial profile but also provided her with an acceptable and stable occlusion. However, during the therapy, alignment of her lower anterior teeth resulted in a Miller’s Class III recession on her lower right central incisor (Figure 1).¹¹ An intraoral periapical radiograph revealed a moderate amount of interproximal bone loss between the two lower central incisors (Figure 2). The recession depth was 4 mm with 2 mm of probing pocket depth, resulting in 6 mm of clinical attachment loss. The width of the attached gingiva was barely 1 mm with an inadequate depth of the labial vestibule. A periodontal mucogingival surgical procedure comprising of subepithelial connective tissue graft to correct the gingival recession was planned.^12,13

The recession site was surgically prepared by raising a split thickness flap extending up to one tooth on either side of the recession defect using submarginal horizontal incisions terminating not less than 0.5 mm away from the gingival margin on the adjacent teeth to avoid development of recession. Next, vertical incisions were made perpendicular to the horizontal incisions starting at the termination point of horizontal incisions and extending into the alveolar mucosa (Figure 3). The partial thickness flap was elevated to such an extent so as to be coronally repositioned without any tension. A subepithelial connective tissue graft was harvested from the palatal aspect of premolars, not extending beyond half the maxillary first molar to cover the recession site (Figure 4). Hand instruments were used to clean and plane the root surface, and fine diamond burs were used to flatten the root convexity. A slurry of tetracycline hydrochloride (125 mg/ml) was used for 3 minutes to condition the root surface, after which the connective tissue graft was stabilized to the recipient site using sling sutures of 5-0 vicryl1⁴ (Figure 5).

The partial thickness flap was then coronally and laterally advanced to cover as much of the underlying connective tissue graft as possible without creating an excessive pull on the vestibular fold to enable maximum blood supply and nourishment. The graft was sutured again using 5-0 vicryl sutures (Figure 6). Tissue tension was relieved using a small horizontal incision at the depth of the vestibule. A periodontal dressing was placed over the surgical site for a period of 2 weeks. After 14 days, sutures were removed and the patient was instructed to avoid mechanical tooth cleaning for 1 month and to use chlorhexidine (0.12%) as a mouth rinse twice daily and clean the wound site with cotton applicator tips as a means of plaque control.

Postoperative assessment at 3 months revealed 50% coverage of the gingival recession (Figure 7), and at 18 months postoperative assessment elucidated an almost complete coverage of the recession site (Figure 8). The patient maintained good oral hygiene and was on regular periodic recalls.

Discussion

Alterations in the mucogingival dimensions may occur during, as well as following, orthodontic therapy. Contrary to past theories, these changes are independent of the apicocoronal width of the keratinized and attached gingiva. Instead, it is the buccolingual thickness (volume) that may be the determining factor for the development of gingival recession and attachment loss during orthodontic therapy.² A tooth that is facially positioned within the alveolar process may show an alveolar bone dehiscence with a thin covering soft tissue. When such a tooth is moved lingually during orthodontic therapy, the gingival dimensions on the labial aspect will increase in thickness. Furthermore, because the mucogingival junction is a stable anatomical landmark and the gingiva is anchored to the supracrestal portion of the root, it will follow the tooth movement leading to gingival augmentation labially.

Orthodontic movement of teeth away from the genetically determined envelope of the alveolar process presents risk for development of mucogingival problems, particularly in thin bone and tissues.¹ During frontal and lateral expansion of teeth tension may develop in the marginal tissues due to forces applied to the teeth. The labial orthodontic tooth movement will not cause soft-tissue recession, per se. However, the thin overlying gingival tissue that will be the consequence of such movement may serve as a locus minoris resistentia to developing soft-tissue defects in the presence of plaque and/or mechanical trauma.²

In the case described, during the orthodontic treatment first premolars were extracted to relieve the anterior crowding; however, for the alignment of the lower teeth the basal arch remained limited. Hence, some amount of lower anterior proclination was built into the occlusion to achieve an ideal overjet and overbite. Any propensity towards recession of the lower anterior teeth during the proclination as part of therapy should have been assessed, and Class II forces delivered through arch wires should have been minimized and root control more critically observed. Use of a preadjusted system also warrants case-to-case assessment regarding the crown position and maintenance of the root position in the alveolar housing.

Pre-orthodontic therapy assessment of the mucogingival apparatus on the pressure side of all teeth that need to be moved should be done with the help of transgingival probing to help determine the thickness of the overlying soft tissue as well as the position of the underlying alveolar bone margin. When tissues are delicate and thin, careful instructions in adequate plaque control measures should be provided to the patient and controlled before and during treatment as well as after therapy in order to reduce the risk of development of labial gingival recession.

In this case, the gingival recession could have been avoided with a better planned and more strategic movement of the lower anterior teeth; if the assessment warranted a movement of the tooth out of its confines of the alveolar housing, then a soft-tissue augmentation procedure to increase the gingival thickness could have been planned prior to tooth movement.

The correction of the Miller’s Class III defect¹¹ on the lower right lateral incisor was, however, done following completion of orthodontic therapy in order to attain optimum function and esthetics. Subepithelial connective tissue grafting is one of the most reliable techniques of obtaining root coverage in wide and deep recessions.¹³ Langer’s technique of connective tissue grafting was performed and an almost complete coverage (75%) of the root was achieved at 18 months postoperative (Table 1).

Conclusion

Poorly executed orthodontic treatment can lead to periodontal tissue breakdown. The combination of inflammation, orthodontic forces, and occlusal trauma may sabotage the status of the periodontium and its associated mucogingival apparatus. Bone dehiscences are known to occur due to uncontrolled expansion of teeth through the cortical plate leading further to soft-tissue deficiencies. It is possible to prevent these defects from being established through a thorough clinical and radiological assessment prior to initiating orthodontic therapy and a timely intervention during tooth movement.

About the Authors

Rashi Chaturvedi, MDS, DNB
Reader
Department of Periodontics
Dr. H.S.J. Institute of Dental Sciences and Hospital
Panjab University
Chandigarh, India

Tarun Das, MDS
Senior Lecturer
Department of Orthodontics
Dr. H.S.J. Institute of Dental Sciences and Hospital
Panjab University
Chandigarh, India

Jyoti Gupta, MDS
Senior Lecturer
Department of Periodontics
Dr. H.S.J. Institute of Dental Sciences and Hospital
Panjab University
Chandigarh, India

Ashish Jain, MDS
Professor and Head
Department of Periodontics
Dr. H.S.J. Institute of Dental Sciences and Hospital
Panjab University
Chandigarh, India