Review question
The aim of this review was to evaluate the efficacy of different surgical procedures to cover exposed tooth roots, when the gum tissue has receded away from the tooth.
Background
Receding gums (also known as gingival recession) is the gradual loss of gum tissue, and if left untreated it can result in exposure of the tooth root, between the gum and the tooth. It can involve one tooth (single recession-type defect) or many teeth (multiple recession-type defects). It can affect the look of the teeth, and is also linked to tooth sensitivity. Exposure of the tooth root can be treated by cosmetic surgery; techniques include grafting and gum regeneration. Grafting involves taking tissue from another place in the mouth and stitching it over the area of the exposed root. With gum regeneration, biomaterials are used to regenerate gum tissue without the need for taking it from the roof of the mouth. Procedures used in gum grafting and gum regeneration include: free gingival grafts, coronally advanced flaps, acellular dermal matrix grafts, laterally positioned flaps and guided tissue regeneration. This review is an update of the original version that was published in 2009.
Study characteristics
Authors from Cochrane Oral Health carried out this review and the evidence is up to date to 15 January 2018. A total of 48 randomised controlled trials on 1227 adults were included with five studies evaluating multiple recession-type defects and the rest single gingival recessions. Most trials followed participants for 6 months to 12 months. The review looked at different interventions: free gingival grafts (FGG), coronally advanced flap (CAF) alone or associated to acellular dermal matrix grafts (ADMG), enamel matrix protein (EMP), guided tissue regeneration with resorbable membranes (GTR rm), guided tissue regeneration with non-resorbable membranes (GTR nrm), GTR rm associated with bone substitutes, platelet-rich plasma or fibrin (PRP or PRF), growth factors (rhPDGF-BB) associated to bone substitutes (b-TCP), subepithelial connective tissue grafts (SCTG) or xenogeneic collagen matrix (XCM). We did not find any trials evaluating laterally positioned flaps (LPF).
Key results
The results of this review have shown that most root coverage periodontal plastic surgery procedures led to gains in reduction of gingival recession. However, we are uncertain about which intervention is the most effective as all studies were judged to be at unclear or high risk of bias. Preferably, subepithelial connective tissue grafts, coronally advanced flap alone or associated with another graft or biomaterial and guided tissue regeneration can be used as root coverage procedures for treating recession-type defects. Limited data exist on how these interventions affect the appearance of the teeth. Adverse effects reported in the studies included discomfort and pain, but these were mainly related to the site where the tissue graft was taken, and occurred mainly within the first week after surgery with no influence on root coverage outcomes. Further research is needed on the results to be achieved from each root coverage periodontal plastic procedure.
Quality of the evidence
We judged the quality of the evidence to be low or very low mainly due to problems with the design of the studies.
Subepithelial connective tissue grafts, coronally advanced flap alone or associated with other biomaterial and guided tissue regeneration may be used as root coverage procedures for treating localised or multiple recession-type defects. The available evidence base indicates that in cases where both root coverage and gain in the width of keratinized tissue are expected, the use of subepithelial connective tissue grafts shows a slight improvement in outcome. There is also some weak evidence suggesting that acellular dermal matrix grafts appear as the soft tissue substitute that may provide the most similar outcomes to those achieved by subepithelial connective tissue grafts. RCTs are necessary to identify possible factors associated with the prognosis of each RCPPS procedure. The potential impact of bias on these outcomes is unclear.
Gingival recession is defined as the oral exposure of the root surface due to a displacement of the gingival margin apical to the cemento-enamel junction and it is regularly linked to the deterioration of dental aesthetics. Successful treatment of recession-type defects is based on the use of predictable root coverage periodontal plastic surgery (RCPPS) procedures. This review is an update of the original version that was published in 2009.
To evaluate the efficacy of different root coverage procedures in the treatment of single and multiple recession-type defects.
Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 15 January 2018), the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 12) in the Cochrane Library (searched 15 January 2018), MEDLINE Ovid (1946 to 15 January 2018), and Embase Ovid (1980 to 15 January 2018). The US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials (15 January 2018). No restrictions were placed on the language or date of publication when searching the electronic databases.
We included randomised controlled trials (RCTs) only of at least 6 months' duration evaluating recession areas (Miller's Class I or II ≥ 3 mm) and treated by means of RCPPS procedures.
Screening of eligible studies, data extraction and risk of bias assessment were conducted independently and in duplicate. Authors were contacted for any missing information. We expressed results as random-effects models using mean differences (MD) for continuous outcomes and odds ratios (OR) for dichotomous outcomes with 95% confidence intervals (CI). We used GRADE methods to assess the quality of the body of evidence of our main comparisons.
We included 48 RCTs in the review. Of these, we assessed one as at low risk of bias, 12 as at high risk of bias and 35 as at unclear risk of bias. The results indicated a greater reduction in gingival recession for subepithelial connective tissue grafts (SCTG) + coronally advanced flap (CAF) compared to guided tissue regeneration with resorbable membranes (GTR rm) + CAF (MD -0.37 mm; 95% CI -0.60 to -0.13, P = 0.002; 3 studies; 98 participants; low-quality evidence). There was insufficient evidence of a difference in gingival recession reduction between acellular dermal matrix grafts (ADMG) + CAF and SCTG + CAF or between enamel matrix protein (EMP) + CAF and SCTG + CAF. Regarding clinical attachment level changes, GTR rm + CAF promoted additional gains compared to SCTG + CAF (MD 0.35; 95% CI 0.06 to 0.63, P = 0.02; 3 studies; 98 participants; low-quality evidence) but there was insufficient evidence of a difference between ADMG + CAF and SCTG + CAF or between EMP + CAF and SCTG + CAF. Greater gains in the keratinized tissue were found for SCTG + CAF when compared to EMP + CAF (MD -1.06 mm; 95% CI -1.36 to -0.76, P < 0.00001; 2 studies; 62 participants; low-quality evidence), and SCTG + CAF when compared to GTR rm + CAF (MD -1.77 mm; 95% CI -2.66 to -0.89, P < 0.0001; 3 studies; 98 participants; very low-quality evidence). There was insufficient evidence of a difference in keratinized tissue gain between ADMG + CAF and SCTG + CAF. Few data exist on aesthetic condition change related to patients' opinion and patients' preference for a specific procedure.