Gingival recession is defined as:
The displacement of the soft tissue margin apical to the cemento–enamel junction (Glossary of Periodontal Terms).
It is a frequent in patients with both good and poor standards of oral hygiene (Loe 1992). More than 50% of the population has one or more sites with gingival recession of 1 mm or more.
Classification of gingival recession
Sullivan and Atkins (1968) classified gingival recession into four categories: deep-wide, shallow-wide, deep-narrow, and shallow-narrow. Of these, they felt that deep-wide gingival recession was the most difficult to treat and offered the least predictability for attaining root coverage.
In 1985 Miller expanded this classification for gingival recession to take into account the nature and quality of gingival recession and its relationship to the adjacent interproximal tissue height. He proposed a classification system of recession based on extent of the recession itself, level of interdental periodontal support and position of the tooth in the arch. The level of interdental periodontal support (Miller 1985) is universally recognized to be very important for the outcome of root coverage and is one of the clinical indicators generally used to predict outcome. According to the Miller classification (Miller 1985), Class I and II type defects, in which the interdental bone support is intact, have the best potential for complete root coverage, while only partial root coverage is thought to be achievable in Miller Class III and IV type defects. These defects are associated with loss of interdental bone or malposition and only partial root coverage is achievable. However, a recent study (Aroca 2010) on Miller Class III recessions reported complete root coverage in 38% of patients treated with a modified tunnel ⁄ connective tissue graft technique, therefore challenging Miller’s dogma. Evidence on treating Miller Class III and IV defects is both scarce and weak and does not provide any clear indications on the potential of interproximal bone loss to impact on root coverage.
Indications for treatment of gingival recession
Despite the wide prevalence of gingival recession, their occurrence is not so detrimental to the longevity of the teeth. Most of the patients will be able to retain their teeth if further loss of attachment can be prevented by proper plaque control. However, patients may require treatment of gingival recession if:
- Patient is not pleased with the appearance of the recession area (Esthetic)
- The area affected by the recession presents hot/cold sensitivity (Dentinal hypersenstivity)
- The recession is progressing despite good oral hygiene (Progression despite treatment)
- Patient can not perform proper oral hygiene due to impinging of soft tissue (shallow vestibule, high frenum insertion, total absence of keratinized tissue).
Surgical technique for treatment of gingival recession
In broad terms, three different approaches can be identified from the published literature:
- The free gingival graft (FGG) (Sullivan & Atkins 1968),
- The coronally advanced flap (CAF) (Allen & Miller 1989),
- Combined procedures (CAF+), based on a coronally advanced flap with tissue (CT) or material (XG) interposed between the flap and the root surface.
The most common of the latter approaches are based on a coronally advanced flap plus a connective tissue graft (CAF+CT) (Langer & Langer 1985), a non-resorbable barrier (Pini Parto 1992), a bio-resorbable barrier (Pini Prato 1992), enamel matrix derivative (Rasperini 2000), platelet-rich gel (Keceli 2008), acellular dermal matrix (Harris 1998), or living tissue-engineered human fibroblast-derived dermal substitute (Wilson 2005, McGuire 2005).
Coronally Advanced Flap
This procedure can be performed with vertical incisions (single/multiple recessions) or without vertical incisions (Zucchelli & de Sanctis 2000) (multiple recessions only). This has been demonstrated to be a predictable procedure, with positive long-term outcome (Pini Prato 2012).
Indication: Single or multiple recessions. No need for a second surgical site (graft). Excellent esthetic result. Good chance to achieve root coverage. Good long-term predictability. High benefit/cost ratio.
Contraindications: Shallow vestibule. Limited or not keratinized tissue.
Coronally Advanced Flap + Connective Tissue
Historically the use of connective tissue grafts, either partially or completely covered by a coronally advanced flap, was suggested. These approaches consisted of thick and large connective tissue grafts sutured close to the cemento-enamel junction and resulted in a high prevalence of complete root coverage. However, excessive thickness of the graft might result in compromised esthetic results (too bulky). Recently, Zucchelli (Zucchelli 2003) proposed the use of thin (~1mm) connective tissue grafts with better esthetic outcome.
Indication: Single or multiple recessions. Good/Excellent esthetic result. High chance to achieve root coverage. Increase in keratinized tissue. Excellent long-term predictability and stability. Low financial cost.
Contraindications: Shallow vestibule. Donor site. Low benefit/cost ratio (increased chair time, increased morbidity).
Coronally Advanced Flap + Grafting Material
Barrier membranes have been proposed and tested by many authors. Both animal and human histology studies demonstrate the potential of this approach to regenerate periodontium with formation of cementum, bone and periodontal ligament coronal to the baseline position of the gingival margin. Animal and human histology studies have proven the potential of enamel matrix derivative associated with coronally advanced flap therapy to induce periodontal regeneration.Acellular dermal matrix has been proposed to treat recession defects in combination with advanced flaps to avoid the need to harvest connective graft from the palate, thereby eliminating the second surgical site and consequently decreasing morbidity.
Indication: Multiple recessions. Excellent esthetic result (Emdogain only). High chance to achieve root coverage (Emdogain). Increase in keratinized tissue (Emdogain). High benefit/cost ratio (no morbidity, reduced chair time).
Contraindications: Shallow vestibule. Donor site. Low benefit/cost ratio (increased chair time, increased morbidity). Long term predictability and stability unknown. Increased cost.
Free Gingival Graft + Coronally Advanced Flap:
This is a procedure in two steps. The first step consists in placing a FGG in the area that presents gingival recession. After 4-6 weeks a CAF procedure is performed to achieved coverage of the exposed root surface. More info on the Free Gingival Graft procedure can be found in this post.
Indication: Single or multiple recessions. Good chance to achieve root coverage. Good long-term predictability. Low financial cost. Increase vestibular depth. Increase in keratinized tissue.
Contraindications: Second surgical site (graft). Poor esthetic result on short-term. Two surgical procedure.
Factors that contribute to the predictability of root coverage procedures
Factors affecting the predictability of root coverage procedures can be divided into three different categories: patient-related factors, tooth ⁄ site-related factors and technique-related factors.
Poor oral hygiene will negatively influence the success of root coverage (Caffesse 2000). Traumatic toothbrushing will also affect the success of root coverage (Wennstrom & Zucchelli 1996). A recent systematic review (Chambrone) concluded that smoking may negatively influence gingival recession reduction and clinical attachment gain. However, another study did not find a difference between smokers and non-smokers. In most of the study cited by Chambrone smoking was a secondary outcome variable, meaning that the study was not designed to study the influence of smoking on root coverage.
Many tooth-related factors, commonly associated with reduced root coverage, such as: root concavity, cervical lesion, tooth malpositioning, depth of the vestibule, tooth vitality, etc, have never been investigated in clinical study. Therefore most of this criteria are arbitrarily considered risk factors. Probably the most cited factor is the interdental bone level (Miller 1985). The level of the interproximal bone and soft tissue seems to dictate the coronal level of root coverage achievable. Flap thickness is also significantly associated with root coverage. A flap thickness of >0.8 mm was associated with complete root coverage (Baldi 1999). Presence of keratinized tissue has also been associated with complete root coverage (Pini Prato 2012). Each millimeter of additional keratinized tissue at baseline is associated with an increment of 0.23 mm of recession reduction at the follow-up visit.
Mechanical root instrumentation seems to be an important factor in achieving root coverage. Ultrasonic and hand instruments seem to provide similar results in this regard. Moreover, Pini Prato assessed the influence of polishing vs scaling and root planing and no significant difference was found. This would favor a more conservative approach of the root surface (only polishing). Handling of the soft tissue also plays a role in achieving complete root coverage. The use of vertical releasing incision might influence the vascularity of the flap. The vascularization of the pedicle flap when performing a coronally advanced flap can be improved if vertical releasing incisions are avoided. Zucchelli & De Sanctis proposed a surgical technique to treat multiple adjacent recession defects based on an envelope type of flap without vertical releasing incisions. Tension free adaptation of the flap (0 to 0.4 g) is also an important factor (Pini Prato). The same author proved that the position of the gingival margin in relation to the cemento–enamel junction is an important factor in achieving complete root coverage with coronally advanced flap therapy. Coronal displacement of the flap of ≥2 mm was associated with complete root coverage in 100% of the patients. Operator skill is another important factor.
Different agents are used for root biomodification (citric acid, tetracycline-HCl, EDTA). These agents have been used to remove the smear layer produced by root instrumentation, to expose the collagen fibrils of the dentin matrix facilitating the formation of new connective tissue attachment and to remove cytopathic substances from infected cementum that inhibit human gingival fibroblast growth. Two systematic reviews (Oates 2003, Roccuzzo 2002) concluded that there are no significant differences in terms of root coverage between sites treated with root planing alone and sites treated with combined chemical ⁄ mechanical treatment.