The Laterally Closed Tunnel Versus Modified Coronally Advanced Tunnel for Mandibular Anterior Gingival Recession Defects

Gingival recession is defined as the displacement of the soft tissue margin apical to the cementoenamel junction.Different predisposing anatomic features can result in recession such as position and anatomy of teeth in the dental arch, bony dehiscence, thickness of the alveolar mucosa, muscle pull, orthodontic treatment, thin gingival biotype, buccal prominence of teeth, lack of keratinized tissue, high frenum attachment, or patient related factors such as vigorous brushing or chronic gingival inflammation.

It is a common finding in patient with a high standard of oral hygiene as well as in periodontally untreated populations with poor oral hygiene.The migration of the marginal tissue to an apical position may lead to esthetic concern, dentin hypersensitivity, root caries, and cervical wear.

Mandibular gingival recession defects present significant therapeutic challenges such as shallow vestibular depth, high frenal attachment, thin soft tissue biotypes leading to thin coronally advanced flaps, and thin often dehisced labial bone.Due to these factors the mandibular sites suffers strong and constant tension in comparison to the maxilla, hence there is lack of predictability in the mandibular sites.

Various surgical techniques have been proposed for the treatment of isolated mandibular recessions including the use of fully or partially epithelized free gingival grafts (FGG) or sub epithelial connective tissue graft in conjunction with various types of flaps eg: (envelope, coronally or laterally positioned flap, double pedicle flap (DPF) or tunnelling (TUN) alone or combined with laterally positioned pedicle flaps (LPPF).

Coronally advanced flap (CAF) +connective tissue graft (CTG) is considered as the gold standard treatment in reducing or eliminating gingival recession. Tunnel technique was first introduced by Allen in 19949, and its modifications by Zabalegui in 199910, Modified Coronally Advanced Tunnel (MCAT) by Azzi et al 2002 and Microsurgical CAT by Zuhr 2007.

However, in deep isolated mandibular recessions located in the anterior area, tension free coronal displacement of the flap can be extremely difficult and may result in decreased vestibular depth and flap dehiscence due to increased flap tension.

Therefore a new clinical approach of The Laterally Closed Tunnel (LCT), specifically designed for deep isolated anterior Mandibular Millers class I, II and III recession has been introduced to predictably cover recession and minimize the risk for post operative complications caused by unfavourable anatomical situations.

The important aspect of LCT is the wide mesiodistal and apical mobilisation of the tunnel which enables tension free lateral movement of the flap margins to cover the graft and the recession. The tension free lateral movement and the passive lateral closure of the tunnel margins maybe advantageous in the treatment of isolated deep recessions located in areas with inserting frenula or shallow vestibule, which makes a coronal tension free advancement of the flap extremely difficult.

Beside the tension free flap preparation, the use of SCTG plays a key role in increasing flap thickness and blood clot stability and in providing the cells needed for soft tissue regeneration and keratinization.

Inclusion criteria

• Isolated Miller's class I, II, III or combined recession defects in mandibular arch.
• Age >/= 18 years.
• Patients with healthy or treated periodontal conditions.
• Patients willing to participate in the study.
• Absence of uncontrolled medical conditions.
• Full mouth plaque score </= 10%(O'Leary 1972).
• Full mouth bleeding score <10%(Ainamo and Bay 1975).
• Patients with esthetic concerns.

Exclusion criteria

• Pregnant or lactating females.
• Tobacco smoking.
• Uncontrolled medical conditions.
• Untreated periodontal conditions.
• Use of systemic antibiotics in the past 3 months.
• Patients treated with any medication known to cause gingival hyperplasia.
• Drug and alcohol abuse.
• No occlusal interferences.