Coverage of Miller Class I and II Recession Defects Using Enamel Matrix Proteins Versus Coronally Advanced Flap Technique: A 2-Year Report

Enhancing attachment of human gingival fibroblasts to periodontally compromised teeth: A comparative analysis of hyaluronic acid, EDTA, enamel matrix derivatives

Background

Gingival recession is a characteristic indicator of periodontitis and one of the factors that contributes to increased tooth clinical crown length. Patients with root exposure frequently undergo periodontal surgical procedures in addition to adjunctive therapy to increase root coverage area and soft tissue stability.

Purpose

This study aimed to evaluate fibroblast-root surface adhesion and determine whether periodontitis-damaged root surface microstructure can be restored using ethylenediaminetetraacetic acid (EDTA) and an enamel matrix derivative (EMD), individually or in combination.

Material and methods

Teeth extracted from patients with periodontal disease were used to create 60 samples, with each group containing six specimens. The test groups were provided root planing or root condition-specific materials (hyaluronic acid [HA], 24% EDTA, EMD, or EDTA/EMD) for varying treatment time periods. In contrast, the control group did not undergo any surface modifications. The samples and fibroblast cells were incubated for 72 h. The number of living cells on the root surface in each group was calculated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay (cell viability assessment).

Results

The control, root planing, and EMD groups showed that the root surfaces treated with EDTA for 4 min had significantly better cell adhesion. Surface EDTA treatment for 2 min significantly promoted cell attachment compared to root planing treatment. The root surfaces modified with EDTA/EMD for 2 and 4 min showed significantly improved cellular migration and adhesion compared to the root surface treated with root planing.

Conclusion

EDTA and EDTA/EMD substantially affected the root surface, which was related to the length of the treatment process. This effect shifts the surface properties, alters fibroblast interactions with the root surface, and recruits more cells to cover a larger area.

Efficacy of biologics in root coverage and gingival augmentation therapy: An American Academy of Periodontology best evidence systematic review and network meta-analysis

BACKGROUND

The aim of this systematic review was to assess the efficacy of three biologics, namely autologous blood-derived products (ABPs), enamel matrix derivatives (EMD) and recombinant human platelet-derived growth factor BB (rhPDGF-BB), in root coverage and gingival augmentation therapy.

METHODS

The protocol of this PRISMA 2020-compliant systematic review was registered in PROSPERO (CRD42021285917). After study selection, data of interest were extracted. A network meta-analysis (NMA) was conducted to assess the effect of different surgical interventions on the main clinical outcomes of interest (i.e., mean root coverage [MRC%], complete root coverage [CRC%], keratinized tissue width [KTW], gingival thickness [GT] change, and recession depth [RD] reduction).

RESULTS

A total of 48 trials reported in 55 articles were selected. All studies reported on the treatment of gingival recession defects for root coverage purposes. Forty-six treatment arms from 24 trials were included in the NMA. These arms consisted of treatment with coronally advanced flap (CAF) alone, EMD + CAF, platelet-rich fibrin (PRF) + CAF, and subepithelial connective tissue graft (SCTG) + CAF. Regarding MRC%, SCTG+CAF was associated with a significant higher estimate (13.41%, 95% CI [8.06-18.75], P <  0.01), while EMD+CAF (6.68%, 95% CI [-0.03 to 13.4], P = 0.061) and PRF+CAF (1.03%, 95% CI [-5.65 to 7.72], P = 0.71) failed to show statistically significant differences compared with CAF alone (control group) or with each other. Similarly, only SCTG+CAF led to a significantly higher CRC% (14.41%, 95% CI [4.21 to 24.61], P < 0.01), while treatment arms EMD + CAF (13.48%, 95% CI [-3.34 to 30.32], P = 0.11) and PRF+CAF (-0.91%, 95% CI [-15.38, 13.57], p = 0.81) did not show significant differences compared with CAF alone or with each other. Differences in the CI of PRF+CAF (symmetrical around a zero adjunctive effect) and EMD+CAF (non-symmetrical) suggest that EMD could have some additional value compared with PRF. Treatment with SCTG+CAF led to a statistically significant higher RD reduction (-0.39 mm, 95% CI [-0.55 to 0.22], P < 0.01), however EMD+CAF (-0.13 mm, 95% CI [-0.29 to 0.01], P = 0.08) and PRF+CAF (-0.06 mm, 95% CI [-0.23 to 0.09], P = 0.39) failed to show significant differences compared with CAF or with each other. While SCTG+CAF was associated with a statistically significant higher gain of KTW (0.71 mm, 95% CI [0.48 to 0.93], P < 0.01), EMD+CAF (0.24 mm, 95% CI [-0.02 to 0.51], P = 0.08) and PRF+CAF (0.08 mm, 95% CI [-0.23 to 0.41], P = 0.58) did not result into significant changes compared with CAF alone or with each other. Regarding the use of rhPDGF-BB+CAF, although available studies have reported equivalent results compared with SCTG+CAF, evidence is very limited.

CONCLUSIONS

The use of ABPs, EMD, or rhPDGF-BB in conjunction with a CAF for root coverage purposes is safe and generally promotes significant improvements respective to baseline clinical parameters. However, the adjunctive use of ABPs and EMD does not provide substantial additional improvements in terms of clinical outcomes and patient-reported outcome measures to those achieved using CAF alone, when baseline KTW is >2 mm. Both PRF+CAF and EMD+CAF rendered inferior MRC%, CRC%, RD reduction, and KTW gain compared with SCTG+CAF, which should still be considered the gold-standard in root coverage therapy. Although some studies have reported equivalent results for rhPDGF-BB+CAF compared with the gold-standard intervention, limited evidence precludes formal comparisons with CAF or SCTG+CAF that could be extrapolated to guide clinical practice.

Enamel Matrix Derivatives for Periodontal Regeneration: Recent Developments and Future Perspectives

In the era of the growing population, the demand for dental care is increasing at a fast pace for both older and younger people. One of the dental diseases that has attracted significant research is periodontitis. Periodontal therapy aims to regenerate tissues that are injured by periodontal disease. During recent decades, various pioneering strategies and products have been introduced for restoring or regeneration of periodontal deficiencies. One of these involves the regeneration of tissues under guidance using enamel matrix derivatives (EMDs) or combinations of these. EMDs are mainly comprised of amelogenins, which is one of the most common biological agents used in periodontics. Multiple studies have been reported regarding the role of EMD in periodontal tissue regeneration; however, the extensive mechanism remains elusive. The EMDs could promote periodontal regeneration mainly through inducing periodontal attachment during tooth formation. EMD mimics biological processes that occur during periodontal tissue growth. During root development, enamel matrix proteins are formed on the root surface by Hertwig's epithelial root sheath cells, initiating the process of cementogenesis. This article reviews the challenges and recent advances in preclinical and clinical applications of EMDs in periodontal regeneration. Moreover, we discuss the current evidence on the mechanisms of action of EMDs in the regeneration of periodontal tissues.

Does the subepithelial connective tissue graft in conjunction with a coronally advanced flap remain as the gold standard therapy for the treatment of single gingival recession defects? A systematic review and network meta-analysis

BACKGROUND

The aim of this systematic review and network meta-analysis was to assess the efficacy of a bilaminar root coverage technique consisting of the combination of an autogenous subepithelial connective tissue graft (SCTG) and a coronally advanced flap (CAF) compared to the five most indicated alternative approaches for the treatment of single gingival recession defects (GRD).

METHODS

The protocol of this PRISMA 2020-compliant systematic review was registered in PROSPERO (CRD42020221362). Three electronic databases were searched up to September 30^th , 2021 to identify randomized controlled trials that involved the treatment of single GRD without interproximal tissue loss via root coverage procedures. A frequentist network meta-analysis was conducted for complete root coverage (CRC), mean root coverage (MRC) and keratinized tissue width (KTW) changes.

RESULTS

A total of 38 studies reporting on 830 patients and 1,265 GRD were included. SCTG+CAF was ranked as the most efficient treatment approach for MRC, CRC and KTW gain at 6 and 12 months after surgery, except for MRC at the 12-month follow-up where enamel matrix derivative (EMD) plus CAF exhibited superior results.

CONCLUSIONS

SCTG+CAF can be considered the gold standard for the treatment of single GRD. This article is protected by copyright. All rights reserved.

Effect of Root Surface Biomodification on Multiple Recession Coverage with Modified Coronally Advanced Tunnel Technique and Subepithelial Connective Tissue Graft: A Retrospective Analysis

To improve treatment efficacy of gingival recessions (GR), chemical preparation of the exposed root surface was advocated. The aim of this study was to compare the additional influence of root biomodifications with 24% ethylenediaminetetraacetic acid (EDTA) alone or with enamel matrix derivative (EMD) on the 12 month outcomes of modified coronally advanced tunnel (MCAT) with subepithelial connective tissue graft in the treatment of multiple GR. Average root coverage (ARC), complete root coverage (CRC), reduction in GR, reduction in recession width (RW), gain in clinical attachment level (CAL), increase in gingival thickness (GT), increase in keratinized tissue width (KTW) and changes in root coverage esthetic score (RES) were evaluated. A total of 60 patients with 215 GR were enrolled. In 70, GR root surfaces were treated with EDTA + EMD, in other 72, with EDTA, while in the remaining 73 saline solution was applied. ARC was 94%, 89%, and 91% in the EDTA + EMD, the EDTA and the saline groups, respectively (p = 0.8871). Gains in clinical attachment level (CAL; 2.1 ± 1.1 mm) and RES values (9.6 ± 0.9) were significantly higher in the EDTA + EMD group, when compared with two other groups. The differences between other preoperative and postoperative parameters showed statistical significance only within but not between groups. MCAT outcomes may benefit from adjunctive use of EDTA + EMD regarding 12 month CAL gain and professionally assessed esthetics using RES following treatment of GR.

Stability of biomaterials used in adjunct to coronally advanced flap: A systematic review and network meta-analysis

AIM

The objective of this network meta-analysis was to rank different biomaterials used in adjunct to coronally advanced flap (CAF), based on their performance in root-coverage for Miller's Class I and II gingival recessions.

MATERIALS AND METHODS

An electronic database search was carried out in PUBMED, CENTRAL, SCOPUS, and EMBASE to identify the eligible articles and compiled into the citation manager to remove the duplicates. The primary outcome was keratinized gingival tissue width (KGW) and percentage of root coverage (%RC). The treatment effect of different biomaterials was estimated using predictive interval plots and ranked based on biomaterials performance, using multidimensional scale ranking.

RESULTS

CAF + connective tissue graft (CTG), CAF + platelet concentrate matrix (PCM) and acellular dermal matrix (ADM) ranked at the top positions in performance in improving KGW. The highest ranked materials in improving percentage of root coverage in gingival recession were CAF + collagen matrix (CM) + gingival fibroblasts (GF), CAF + ADM + platelet rich plasma (PRP) and CAF + ADM, as compared to CAF alone.

CONCLUSION

CTG, ADM, platelet concentrates, and CM + GFs, when used in adjunct to CAF, showed improved stability over ≥12 months of follow-up, better percentage of root coverage, and improved keratinized gingival width.

Soft Tissue Regeneration at Natural Teeth

This article provides an overview of the best-documented surgical techniques for recession coverage and draws conclusions for the clinician. Use of a connective tissue graft with either coronally advanced flap (CAF) or tunnel is the most predictable technique for the treatment of single and multiple gingival recessions. Long-term results exist only for CAF with/without connective tissue graft providing evidence for long-term stability with only minor relapses. Soft tissue replacement materials and biologics may represent a valuable modality to additionally improve the clinical outcomes obtained with CAF alone or, in certain clinical situations, to serve as an alternative to autogenous tissue.

Effect of 24% EDTA root conditioning on the outcome of modified coronally advanced tunnel technique with subepithelial connective tissue graft for the treatment of multiple gingival recessions: a randomized clinical trial

OBJECTIVES

To investigate effects of root conditioning with 24% ethylenediaminetetraacetic acid (EDTA) on the 12-month outcomes after treatment of multiple gingival recessions (GR) with modified coronally advanced tunnel (MCAT) and subepithelial connective tissue graft (SCTG).

MATERIALS AND METHODS

Twenty patients with 142 GR were treated (72 test sites: SCTG + EDTA and 70 control sites: SCTG). Average and complete root coverage (ARC, CRC), gain in keratinized tissue width (KTW), gain in gingival thickness (GT), root esthetic coverage score (RES), and patient-reported outcome measures (PROMs) were evaluated at 12 months post-operatively.

RESULTS

Differences between pre- and post-operative values were statistically significant only within but not between treatment modalities. At 12 months, ARC was 86.0% for SCTG + EDTA-treated and 84.6 for SCTG-treated defects (p = 0.6636). CRC was observed in 90.2% (tests) and 91.4% (controls) of all cases (p = 0.9903). Professional assessment of esthetic outcomes using RES showed highly positive results reaching the value of 8.9 in case of test sites and 8.7 for control sites (p = 0.3358). Severity of pain and swelling did not differ between sites, regardless of whether EDTA was used.

CONCLUSIONS

Test and control sites presented similarly positive outcomes related to root coverage, periodontal and esthetic parameters, and patient satisfaction and self-reported morbidity with no statistical differences between them 12 months after surgery. No significant differences in evaluated variables were observed between sites treated with and without 24% EDTA. Clinical relevance Considering the limitations of the present study, the use of 24% EDTA for root conditioning did not improve 12-month outcomes after treatment of multiple RT1 and RT2 gingival recessions with MCAT and SCTG. Trial registration ClinicalTrials.gov identifier: NCT03354104.

Does enamel matrix derivative application provide additional clinical benefits in the treatment of maxillary Miller class I and II gingival recession? A systematic review and meta-analysis

OBJECTIVE

This review aimed to evaluate the effects of enamel matrix derivative (EMD) in association with coronally advanced flap (CAF) or CAF + connective tissue graft (CTG) when compared with CAF alone or CAF + CTG for the treatment of gingival recessions (GR) in maxillary teeth.

METHODS

Five databases and gray literature were searched up to April 2020, to find randomized clinical trials comparing the clinical effects of CAF + EMD versus CAF alone (first group) or CAF + CTG + EMD versus CAF + CTG (second group) in the treatment of Miller class I and II or Cairo type I gingival recessions (GR). Random effects model of mean differences was used to determine the GR reduction, gain in keratinized tissue width (KTW), and gain in clinical attachment level (CAL). The trial sequential analysis (TSA) was implemented to determine the optimal information size (OIS) and imprecision using the GRADE approach. Bayes factors were calculated as complementary statistical evidence of p value.

RESULTS

From 1349 titles identified, 9 trials representing 336 GR were included. The meta-analysis showed a statistically significant difference for GR reduction and CAL gain in favor CAF + EMD (p ≤ 0.05). The additional effect of EMD showed a statistically significant difference in GR reduction in favor CAF + CTG + EMD (p ≤ 0.05). The differences in KTW gain proved to be not statistically significant in both comparison groups. The OIS were not met among meta-analyses. Evidence certainty according the GRADE approach proved to be moderate for GR reduction and gain in CAL, but very low for gain in KTW.

CONCLUSION

The adjunctive application of EMD in the treatment of GR in maxillary teeth either with CAF or CTG provided moderate certainty evidence in favor of their use for reduction in GR and gain in CAL at 6 and 12 months. However, their effect on the increase in keratinized tissue band height showed very low evidence certainty for its use.

CLINICAL RELEVANCE

To know if EMD could improve the results for root coverage.

Periodontal regeneration: a bibliometric analysis of the most influential studies

Aim: The aim of the present study is to identify the most influential research articles and their main characteristics in the specialty of periodontal regeneration. Materials & methods: The Web of Science database advance search was performed in the subject category of 'Dentistry, Oral surgery and medicine' from January 2004 to October 2018 to retrieve citations data. Results: The majority of the articles were published in journals dedicated to the specialty of periodontology. Among the top-cited articles most emphasized study types were randomized control trials (n = 25) and reviews (n = 20). Conclusion: The present bibliometric analysis provides comprehensive information regarding the contributions made in the advancement of regenerative periodontal research. The authors from developed countries and affiliated with interdisciplinary/multicenter institutions have predominantly contributed.

A 3-year prospective clinical and patient-centered trial on subepithelial connective tissue graft with or without enamel matrix derivative in Class I-II Miller recessions

BACKGROUND AND OBJECTIVE

The study compared clinical and patient-centered outcomes of subepithelial connective tissue graft (CTG) with and without enamel matrix derivative (EMD) in the treatment of Class I-II Miller periodontal recession defects.

MATERIAL AND METHODS

This prospective clinical study evaluated 80 patients over a 3 years follow-up in a private periodontal practice. A total of 144 maxillary and mandibular anterior teeth were divided into two groups: group 1 (CTG with EMD-80 teeth) and group 2 (CTG only-64 teeth). Recession (REC), keratinized tissue (KT) width, % root overage, patient-centered outcomes, and pain visual analog scale (P-VAS) were compared between the two groups.

RESULTS

At 3 years follow-up at a patient level, statistically significant changes in REC were achieved in both group 1 (4.65 ± 1.84 to 0.39 ± 0.19 mm) and group 2 (4.43 ± 1.11 to 0.92 ± 0.43 mm). Complete root coverage (CRC) was achieved in 66.4% of group 1 and 50.1% of group 2. At both patient and tooth level, the 3-year outcomes were superior for group 1 compared with group 2 in terms of % root coverage, REC, and KT width. Clinical attachment loss (CAL) was reduced in group 1 compared with group 2 at the tooth level analysis only (<.01). Significantly less pain was reported using the pain visual analog Scale (P < .001) at the two weeks follow-up post-surgery in group 1.

CONCLUSIONS

Addition of EMD results in improved root coverage outcomes and higher amounts of keratinized tissue width 36 months after treatment of multiple adjacent recessions on maxillary and mandibular anterior teeth. The adjunctive use of EMD also resulted in significantly reduced pain 14 days after the surgery.

Subepithelial connective tissue graft with or without enamel matrix derivative for the treatment of multiple Class III-IV recessions in lower anterior teeth: A 3-year randomized clinical trial

BACKGROUND

This study compared clinical and patient-centered outcomes of subepithelial connective tissue graft (CTG) with and without enamel matrix derivative (EMD) in the treatment of multiple Class III-IV Miller periodontal recession (REC) defects on mandibular anterior teeth.

METHODS

This randomized clinical study evaluated 41 patients at 3 years follow-up. One hundred and fifty-six teeth were divided into two groups: test (CTG-EMD, 79 teeth) and control (CTG only, 77 teeth). Clinical REC, keratinized tissue (KT) width, percentage of root coverage, patient-centered outcomes were compared between the two groups.

RESULTS

At 36 months follow-up, patient level analysis showed that REC in the test group reduced significantly (5.71 ± 0.58 mm to 1.57 ± 0.85 mm) compared with the control group (5.94 ± 0.46 mm to 2.51 ± 0.62 mm) (P < 0.001), while KT width increased in the test group (1.51 ± 0.26 mm to 4.18 ± 0.34 mm) and was significantly greater than the control group (1.65 ± 0.21 mm to 2.90 ± 0.20 mm) (P < 0.001). At 36 months, tooth level analysis (Class III and Class IV groups) found less residual REC and increased KT in the test group compared with the control group (P < 0.01). Significantly less pain was reported at 2, 7, and 14 days follow-up post-surgery in the test group (P < 0.001).

CONCLUSIONS

The addition of EMD to CTG results in improved root coverage outcomes and higher amounts of KT width 36 months after treatment of Class III-IV REC on mandibular anterior teeth. The adjunctive use of EMD also resulted in significantly reduced pain 14 days post-surgery.

Efficacy of Enamel Derivatives to Improve Keratinized Tissue as Adjunct to Coverage of Gingival Recessions: A Systematic Review and Meta-Analysis

Background: The systematic review was designed to answer the following focused question: Are enamel matrix derivatives able to improve the quantity of keratinized tissue (KT) around natural dentition in patients with recessions defects after their treatment with periodontal plastic procedures? Methods: Only Randomized Clinical Trials (RCT) in English language evaluating root coverage procedures in combination with enamel matrix derivatives (commercially known as Emdogain^®—EMD), with at least 10 subjects and a minimum duration of six months, were included. The search was applied to PUBMED and SCOPUS and it consists of a combination of MeSH terms and free text words (from January 2000 to June 2019). Risk of bias in individual studies and across studies was also evaluated. Results: After the full text analysis and the exclusion of further 18 articles, 12 articles were finally included. In total 639 recessions were treated (334 tests and 305 control). The recessions defects were classified according to the classification of Miller (Class I, II, III, IV). Only one trial included Miller Class III recessions (7 in total). Enamel matrix derivatives were applied in conjunction with Coronally Advanced Flap (CAF), Coronally Advanced Flap + Sub Epithelial Connective Tissue Graft (CAF + CTG), Semilunar Flap (SF). For the group CAF vs CAF + EMD the mean difference between the keratinized tissue gain in the two procedures was 0.40 mm (95% Confindence Interval Lower/Upper: 0.014–0.81) (p < 0.058); for the comparison CAF + CTG + EMD vs. CAF + CTG the mean difference between the two groups resulted in −0.06 mm (95% Confindence Interval Lower Upper −0.45 to 0.33) (p = 0.7603). Discussion: Randomized clinical trials included medium-low quality evidence. The application of Enamel Matrix Derivatives to surgical procedures aimed to cover gingival recessions does not add robust clinical benefit to conventional plastic procedure alone.

Effect of enamel matrix derivative on wound healing following gingival recession coverage using the modified coronally advanced tunnel and subepithelial connective tissue graft: a randomised, controlled, clinical study

OBJECTIVES

The potential effect of enamel matrix derivative (EMD) on wound healing following recession coverage surgery is still controversially discussed in the literature. The aim of this randomised, controlled, single blinded clinical study was, therefore, to investigate clinically and immunologically the potential effects of EMD on early wound healing and clinical results following treatment of single and multiple gingival recessions by the modified coronally advanced tunnel technique (MCAT) and subepithelial connective tissue graft (sCTG).

MATERIALS AND METHODS

A total of 40 systemically healthy patients with Miller class I, II or III single or multiple gingival recessions were treated with MCAT + sCTG with or without EMD. Patients were consecutively enrolled and randomly assigned to test or control treatment. Inflammatory markers (interleukin (IL)-1β, IL-8, IL-10 and matrix metalloprotease (MMP)-8) were measured at baseline, 2 days and 1 week postoperatively. The following clinical parameters were assessed at baseline and at 6 months postoperatively: Recession Depth (RD), Recession Width (RW), Width of Keratinized Tissue (KT) and Probing Depth (PD). Patient-reported outcomes were analysed by means of a visual analogue scale.

RESULTS

No statistically significant differences were detected between the 2 groups in terms of inflammatory markers and patient-reported outcomes during early wound healing. In the test group, RD was reduced from 4.0 ± 1.2 mm at baseline to 0.9 ± 1.3 mm at 6 months (p < 0.001), while the corresponding values in the control group were 4.5 ± 2.0 mm at baseline and 1.0 ± 1.0 mm at 6 months, respectively. At 6 months, mean root coverage measured 78 ± 26% in the test group and 77 ± 18% in the control group, respectively.

CONCLUSION

Within their limits, the present data have failed to show an influence of EMD on the clinical and immunological parameters related to wound healing following recession coverage surgery using MCAT and sCTG.

CLINICAL RELEVANCE

Early wound healing following recession coverage by means of MCAT and sCTG does not seem to be influenced by the additional application of EMD.

Efficacy of free gingival graft in the treatment of Miller Class I and Class II localized gingival recessions: A systematic review

Background

Currently, the leading theme in mucogingival surgery is the correction of gingival recession defects. Free gingival graft (FGG) has been successfully in use in this category of reconstructive therapeutic modality.

Objectives

The aim of this systematic review was to evaluate the literature with respect to efficacy of FGG in the management of Miller Class I and II localized gingival recessions.

Data Sources

Search strategies were performed via electronic database which included Pubmed-Medline, Google scholar and manual search using University library resources. Two reviewers assessed the eligibility of the studies.

Study Eligibility Criteria

Controlled clinical trials, randomized clinical trials and longitudinal studies evaluating recession areas treated by FGG with minimum of 6 months follow up were included. In-vitro and animal studies, studies mainly done on Miller Class III and IV gingival recession defect, studies on multiple gingival recessions and case series and case reports were excluded from the search.

Results

The electronic and manual search identified a total of 557 articles. A final screen consisted of 39 articles out of which 17 articles were selected for full-text assessment. Finally, 7 articles were selected for detailed evaluation for this systematic review. FGG has shown significant results in all the studies except for one study.

Conclusion

FGG produces substantial results, however, highly depends on the case selection and operator's skill and experience. FGG gives an impression of being the best alternative option in zones where gingival recession presents with inadequate width of attached gingiva and depth of vestibular fornix.

Root coverage procedures for treating localised and multiple recession-type defects

BACKGROUND

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.

OBJECTIVES

To evaluate the efficacy of different root coverage procedures in the treatment of single and multiple recession-type defects.

SEARCH METHODS

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.

SELECTION CRITERIA

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.

DATA COLLECTION AND ANALYSIS

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.

MAIN RESULTS

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.

AUTHORS' CONCLUSIONS

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.

Xenogenous Collagen Matrix and/or Enamel Matrix Derivative for Treatment of Localized Gingival Recessions: A Randomized Clinical Trial. Part I: Clinical Outcomes

BACKGROUND

Considering xenogeneic collagen matrix (CM) and enamel matrix derivative (EMD) characteristics, it is suggested that their combination could promote superior clinical outcomes in root coverage procedures. Thus, the aim of this parallel, double-masked, dual-center, randomized clinical trial is to evaluate clinical outcomes after treatment of localized gingival recession (GR) by a coronally advanced flap (CAF) combined with CM and/or EMD.

METHODS

Sixty-eight patients presenting one Miller Class I or II GRs were randomly assigned to receive either CAF (n = 17); CAF + CM (n = 17); CAF + EMD (n = 17), or CAF + CM + EMD (n = 17). Recession height, probing depth, clinical attachment level, and keratinized tissue width and thickness were measured at baseline and 90 days and 6 months after surgery.

RESULTS

The obtained root coverage was 68.04% ± 24.11% for CAF; 87.20% ± 15.01% for CAF + CM; 88.77% ± 20.66% for CAF + EMD; and 91.59% ± 11.08% for CAF + CM + EMD after 6 months. Groups that received biomaterials showed greater values (P <0.05). Complete root coverage (CRC) for CAF + EMD was 70.59%, significantly superior to CAF alone (23.53%); CAF + CM (52.94%), and CAF + CM + EMD (51.47%) (P <0.05). Keratinized tissue thickness gain was significant only in CM-treated groups (P <0.05).

CONCLUSIONS

The three approaches are superior to CAF alone for root coverage. EMD provides highest levels of CRC; however, the addition of CM increases gingival thickness. The combination approach does not seem justified.

Twenty years of enamel matrix derivative: the past, the present and the future

BACGROUND

On June 5th, 2015 at Europerio 8, a group of leading experts were gathered to discuss what has now been 20 years of documented evidence supporting the clinical use of enamel matrix derivative (EMD). Original experiments led by Lars Hammarström demonstrated that enamel matrix proteins could serve as key regenerative proteins capable of promoting periodontal regeneration including new cementum, with functionally oriented inserting new periodontal ligament fibres, and new alveolar bone formation. This pioneering work and vision by Lars Hammarström has paved the way to an enormous amount of publications related to its biological basis and clinical use. Twenty years later, it is clear that all these studies have greatly contributed to our understanding of how biologics can act as mediators for periodontal regeneration and have provided additional clinical means to support tissue regeneration of the periodontium.

AIMS

This review article aims to: (1) provide the biological background necessary to understand the rational for the use of EMD for periodontal regeneration, (2) present animal and human histological evidence of periodontal regeneration following EMD application, (3) provide clinically relevant indications for the use of EMD and (4) discuss future avenues of research including key early findings leading to the development of Osteogain, a new carrier system for EMD specifically developed with better protein adsorption to bone grafting materials.

Does Adjunctive Use of Growth Factors Improve Clinical Outcomes of Soft Tissue Grafting at Miller Class III Recession Defects? A Review of Current Evidence

Focused Clinical Question In patients with gingival recession that is classified as Miller Class III, does adjunctive use of local growth factors with gingival grafting procedures improve clinical outcomes? Clinical Scenario A 31-year-old female presents with a chief complaint of gingival recession (GR) at teeth #4 to #13 (Fig. 1). Interproximal bone loss coronal to the level of the buccal GR is present. She is concerned about esthetics and would like to maximize her chance for complete root coverage. Her medical history is non-contributory, and she has no contraindications to routine dental care. Because of the number of teeth involved and the difficulty in harvesting autogenous tissues, she is treated with acellular dermal matrix^§ and enamel matrix derivative^‖ with a coronally advanced flap at teeth #4 to #13 (Figs. 2 and 3). Final results reveal significant root coverage on all teeth and complete root coverage on teeth #7 to #10. This results in an esthetically acceptable result (Fig. 4).

Periodontal soft tissue root coverage procedures: a systematic review from the AAP Regeneration Workshop

BACKGROUND

This paper aims to create a "bridge" between research and practice by developing a practical, extensive, and clinically relevant study that translates evidence-based findings on soft tissue root coverage (RC) of recession-type defects to daily clinical practice.

METHODS

This review is prepared in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement based on the proposed focused questions. A literature search with no restrictions regarding status or the language of publication was performed for MEDLINE and EMBASE databases up to and including June 2013. Systematic reviews (SRs), randomized clinical trials, controlled clinical trials, case series, and case reports evaluating recession areas that were treated by means of RC procedures were considered eligible for inclusion through the three parts of the study (part I, an overview of the base of SRs; part II, an alternative random-effects meta-analyses on mean percentage of RC and sites exhibiting complete RC; and part III, an SR of non-randomized trials exploring other conditions not extensively evaluated by previous SRs). Data on Class I, II, III, and IV recessions, type of histologic attachment achieved with treatment, recipient- and donor-site anatomic characteristics, smoking-related outcomes, root surface conditions, tooth type and location, long-term effectiveness outcomes, unusual conditions that may be reported during conventional daily practice, and patient-centered outcomes were assessed as well.

RESULTS

Of the 2,456 potentially eligible trials, 234 were included. Data on Class I, II, III, and IV gingival recessions, histologic attachment achieved after treatment, recipient- and donor-site anatomic characteristics, smoking-related outcomes, root surface conditions/biomodification, tooth type and location, long-term effectiveness outcomes and unusual conditions that may be reported during conventional daily practice, and patient-centered outcomes (i.e., esthetic, visual analog scale, complications, hypersensitivity, patients perceptions) were assessed. Subepithelial connective tissue (CT)-based procedures and coronally advanced flap plus acellular dermal matrix grafts, enamel matrix derivative, or collagen matrix led to the best improvements of recession depth, clinical attachment level (CAL) gain, and keratinized tissue (KT). Some conditions, such as smoking and use of magnification, may affect RC outcomes.

CONCLUSIONS

All RC procedures can provide significant reduction in recession depth and CAL gain for Miller Class I and II recession-type defects. Subepithelial CT graft-based procedures provided the best outcomes for clinical practice because of their superior percentages of mean and complete RC, as well as significant increase of KT.

Evaluation of recession defects treated with coronally advanced flaps and either recombinant human platelet-derived growth factor-BB plus β-tricalcium phosphate or connective tissue: comparison of clinical parameters at 5 years

BACKGROUND

In a previously reported split-mouth, randomized controlled trial, Miller Class II gingival recession defects were treated with either a connective tissue graft (CTG) (control) or recombinant human platelet-derived growth factor-BB + β-tricalcium phosphate (test), both in combination with a coronally advanced flap (CAF). At 6 months, multiple outcome measures were examined. The purpose of the current study is to examine the major efficacy parameters at 5 years.

METHODS

Twenty of the original 30 patients were available for follow-up 5 years after the original surgery. Outcomes examined were recession depth, probing depth, clinical attachment level (CAL), height of keratinized tissue (wKT), and percentage of root coverage. Within- and across-treatment group results at 6 months and 5 years were compared with original baseline values.

RESULTS

At 5 years, all quantitative parameters for both treatment protocols showed statistically significant improvements over baseline. The primary outcome parameter, change in recession depth at 5 years, demonstrated statistically significant improvements in recession over baseline, although intergroup comparisons favored the control group at both 6 months and 5 years. At 5 years, intergroup comparisons also favored the test group for percentage root coverage and change in wKT, whereas no statistically significant intergroup differences were seen for 100% root coverage and changes to CAL.

CONCLUSIONS

In the present 5-year investigation, treatment with either test or control treatments for Miller Class II recession defects appear to lead to stable, clinically effective results, although CTG + CAF resulted in greater reductions in recession, greater percentage of root coverage, and increased wKT.

Coronally advanced flap alone or with connective tissue graft in the treatment of single gingival recession defects: a long-term randomized clinical trial

BACKGROUND

Numerous surgical approaches for the treatment of single gingival recession (GR) defects are documented in the literature. The aim of this 5-year, split mouth-design, randomized clinical trial was to evaluate the effectiveness of coronally advanced flap (CAF) alone versus CAF with connective tissue graft (CAF+CTG) in the treatment of single Miller Class I and II GR defects.

METHODS

Thirty-seven patients with 114 bilateral, single Miller Class I and II GR defects were treated with CAF on one side of the mouth and CAF+CTG on the other side. Clinical measurements (GR length [REC], keratinized tissue width [KT], complete root coverage [CRC], and percentage of root coverage [PRC]) were evaluated before surgery and after 6, 12, 24, and 60 months.

RESULTS

There was a significant reduction of REC and increase of KT after surgery in both groups. CAF+CTG showed significantly better results for all evaluated clinical parameters in all observed follow-up periods. Miller Class I defects showed better results in terms of REC, CRC, and PRC, whereas Miller Class II showed better results in KT, both in favor of CAF+CTG. Miller Class I defects showed better results than Miller Class II GR defects regardless of the surgical procedure used.

CONCLUSIONS

Both surgical procedures were effective in the treatment of single Miller Class I and II GR defects. The CAF+CTG procedure provided better long-term outcomes (60 months postoperatively) than CAF alone. Long-term stability of the gingival margin is less predictable for Miller Class II GR defects compared to those of Class I.

Coronally advanced flap and combination therapy for root coverage. Clinical strategies based on scientific evidence and clinical experience

During the past three decades, several surgical techniques have been proposed to treat single and multiple gingival recessions. Evidence indicates that coronally advanced flap-based approaches result in the best clinical results. Among all the different techniques, the use of a graft under a coronally advanced flap results in the best short- and long-term outcomes in terms of root coverage and gain in keratinized tissue. The use of a coronally advanced flap + connective tissue graft would appear to be the best choice for root coverage. However, harvesting a graft from the palate adds morbidity, surgical chair-time and requires increased surgical skills. A potential alternative could be the use of enamel matrix derivatives under a coronally advanced flap, and this achieves similar clinical outcomes and is less invasive, but adds economic costs to the treatment. Evidence shows that a coronally advanced flap alone in many instances results in complete root coverage and is stable over time. A coronally advanced flap is less invasive for the patient, requires less chair-time and probably less surgical skill. It would therefore be desirable to use a coronally advanced flap approach when indicated. It has been hypothesized that a coronally advanced flap approach alone could be successfully applied when the residual gingiva is thick and wide, although existing evidence does not support this hypothesis in full. Accordingly, the adjunctive use of a graft or enamel matrix derivatives could be restricted to sites at which there is thin and narrow residual gingiva.

Ten-year results following treatment of intrabony defects with an enamel matrix protein derivative combined with either a natural bone mineral or a β-tricalcium phosphate

BACKGROUND

The purpose of the present study is to evaluate the 10-year results following treatment of intrabony defects treated with an enamel matrix protein derivative (EMD) combined with either a natural bone mineral (NBM) or β-tricalcium phosphate (β-TCP).

METHODS

Twenty-two patients with advanced chronic periodontitis and displaying one deep intrabony defect were randomly treated with a combination of either EMD + NBM or EMD + β-TCP. Clinical evaluations were performed at baseline and at 1 and 10 years. The following parameters were evaluated: plaque index, bleeding on probing, probing depth, gingival recession, and clinical attachment level (CAL). The primary outcome variable was CAL.

RESULTS

The defects treated with EMD + NBM demonstrated a mean CAL change from 8.9 ± 1.5 mm to 5.3 ± 0.9 mm (P <0.001) and to 5.8 ± 1.1 mm (P <0.001) at 1 and 10 years, respectively. The sites treated with EMD + β-TCP showed a mean CAL change from 9.1 ± 1.6 mm to 5.4 ± 1.1 mm (P <0.001) at 1 year and 6.1 ± 1.4 mm (P <0.001) at 10 years. At 10 years two defects in the EMD + NBM group had lost 2 mm, whereas two other defects had lost 1 mm of the CAL gained at 1 year. In the EMD + β-TCP group three defects had lost 2 mm, whereas two other defects had lost 1 mm of the CAL gained at 1 year. Compared with baseline, at 10 years, a CAL gain of ≥3 mm was measured in 64% (i.e., seven of 11) of the defects in the EMD + NBM group and in 82% (i.e., nine of 11) of the defects in the EMD + β-TCP group. No statistically significant differences were found between the 1- and 10-year values in either of the two groups. Between the treatment groups, no statistically significant differences in any of the investigated parameters were observed at 1 and 10 years.

CONCLUSION

Within their limitations, the present findings indicate that the clinical improvements obtained with regenerative surgery using EMD + NBM or EMD + β-TCP can be maintained over a period of 10 years.

Early and late studies of EMD use in periodontal intrabony defects

BACKGROUND AND OBJECTIVE

The clinical efficacy of EMDs for the treatment of periodontal infrabony defects has been reported. However, recent publications have questioned the validity of results from early findings. Hence, the purpose of this study was to compare the results obtained from early and late studies when EMD was used as an adjunct in treating human intrabony defects during flap surgery. The aim of this meta-analysis was to evaluate the validity of results published from early studies compared with those published from later studies.

MATERIAL AND METHODS

PubMed and MEDLINE searches were performed. The evaluation period was 1997-2010 and it was divided into two groups of equal periods of time: early studies (1997-2003) and late studies (2004-2010). The clinical parameters assessed were clinical attachment level (CAL), probing pocket depth and bone gain (BG; measured as a percentage or in mm).

RESULTS

No statistically significant difference was found between the results obtained from early studies (1997-2003) and late studies (2004-2010) with regards to CAL gain, probing pocket depth reduction and BG. Nonetheless, both study periods showed a benefit for using EMD to treat periodontal infrabony defects when compared with the groups without EMD during open flap surgery.

CONCLUSIONS

The results obtained from this study failed to show any potential differences between the results published from early studies and late studies with regards to the clinical effectiveness of EMD in treating periodontal infrabony defects.

Enamel matrix protein derivatives: role in periodontal regeneration

The role of regenerative periodontal therapy is the reconstitution of lost periodontal structures, ie, new formation of root cementum, periodontal ligament, and alveolar bone. The outcome of basic research has pointed to the important role of enamel matrix protein derivative (EMD) in periodontal wound healing. Histologic results from animal and human studies have shown that treatment with EMD promotes periodontal regeneration. Moreover, clinical studies have indicated that treatment with EMD positively influences periodontal wound healing in humans. The goal of this paper is to review the existing literature on EMD.

Periodontal regeneration with enamel matrix derivative in reconstructive periodontal therapy: a systematic review

BACKGROUND

Enamel matrix derivative (EMD) is commonly used in periodontal therapy. The aim of this systematic review is to give an updated answer to the question of whether the additional use of EMD in periodontal therapy is more effective compared with a control or other regenerative procedures.

METHODS

A literature search in MEDLINE (PubMed) for the use of EMD in periodontal treatment was performed up to May 2010. The use of EMD in treatment of intrabony defects, furcations, and recessions was evaluated. Only randomized controlled trials with ≥1 year of follow-up were included. The primary outcome variable for intrabony defects was the change in clinical attachment level (CAL), for furcations the change in horizontal furcation depth, and for recession complete root coverage.

RESULTS

After screening, 27 studies (20 for intrabony defects, one for furcation, and six for recession) were eligible for the review. A meta-analysis was performed for intrabony defects and recession. The treatment of intrabony defects with EMD showed a significant additional gain in CAL of 1.30 mm compared with open-flap debridement, EDTA, or placebo, but no significant difference compared with resorbable membranes was shown. The use of EMD in combination with a coronally advanced flap compared with a coronally advanced flap alone showed significantly more complete root coverage (odds ratio of 3.5), but compared with a connective tissue graft, the result was not significantly different. The use of EMD in furcations (2.6 ± 1.8 mm) gave significantly more improvement in horizontal defect depth compared with resorbable membranes (1.9 ± 1.4 mm) as shown in one study.

CONCLUSIONS

In the treatment of intrabony defects, the use of EMD is superior to control treatments but as effective as resorbable membranes. The additional use of EMD with a coronally advanced flap for recession coverage will give superior results compared with a control but is as effective as a connective tissue graft. The use of EMD in furcations will give more reduction in horizontal furcation defect depth compared with resorbable membranes.

Treatment of class III multiple gingival recessions: a randomized-clinical trial

BACKGROUND

The aim of this controlled randomized split-mouth study was to evaluate whether a modified tunnel/connective tissue graft (CTG) technique - enamel matrix derivative (EMD) combination will improve the treatment of multiple class III recession when compared with the same technique alone.

MATERIALS AND METHODS

Twenty healthy subjects with a mean age of 31.7 years, were enrolled for the trial in a university periodontal clinic. Patients with at least three adjacent gingival recessions on both sides of the mouth were treated with a modified tunnel/CTG technique. On the test side, an EMD was used in addition. Clinical parameters were measured at baseline, 28 days, 3, 6 and 12 months after the surgery. Results are presented at the subject level.

RESULTS

The mean root coverage from baseline to 1 year post-surgery was 82% for the test group and 83% for the control group. Complete root coverage was achieved at 1 year in eight (38%) of the 20 surgeries (experimental and control group).

CONCLUSIONS

One-year results indicate that the modified tunnel/CTG technique is predictable for the treatment of multiple class III recession-type defects. The addition of EMD does not enhance the mean clinical outcomes.

Root coverage procedures for the treatment of localised recession-type defects

BACKGROUND

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 periodontal plastic surgery (PPS) procedures.

OBJECTIVES

To evaluate the effectiveness of different root coverage procedures in the treatment of recession-type defects.

SEARCH STRATEGY

The Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE and EMBASE were searched up to October 2008. The main international periodontal journals were handsearched. There were no restrictions with regard to publication status or language of publication.

SELECTION CRITERIA

Only randomised controlled clinical trials (RCTs) of at least 6 months' duration evaluating recession areas (Miller's Class I or II > 3 mm) and that were treated by means of PPS procedures were included.

DATA COLLECTION AND ANALYSIS

Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted independently and in duplicate. Authors were contacted for any missing information. Results were expressed as random-effects models using mean differences for continuous outcomes and risk ratios for dichotomous outcomes with 95% confidence intervals.

MAIN RESULTS

Twenty-four RCTs provided data. Only one trial was considered to be at low risk of bias. The remaining trials were considered to be at high risk of bias. The results indicated a significant greater reduction in gingival recession and gain in keratinized tissue for subepithelial connective tissue grafts (SCTG) compared to guided tissue regeneration with resorbable membranes (GTR rm). A significant greater gain in the keratinized tissue was found for enamel matrix protein when compared to coronally advanced flap (0.40 mm) and for SCTG when compared to GTR rm plus bone substitutes. Limited data exist on aesthetic condition change related to patients' opinion and patients' preference for a specific procedure.

AUTHORS' CONCLUSIONS

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 the treatment of localised recession-type defects. In cases where both root coverage and gain in the keratinized tissue are expected, the use of subepithelial connective tissue grafts seems to be more adequate. Randomised controlled clinical trials are necessary to identify possible factors associated with the prognosis of each PPS procedure. The potential impact of bias on these outcomes is unclear.

Treatment of gingival recession with coronally advanced flap procedures: a systematic review

BACKGROUND

The treatment of buccal gingival recessions is a common requirement due to aesthetic concern or root sensitivity. The aim of this manuscript was to systematically review the literature on coronally advanced flap (CAF) alone or in combination with tissue grafts, barrier membranes (BM), enamel matrix derivative (EMD) or other material for treating gingival recession.

MATERIAL AND METHODS

Randomized clinical trials on treatment of Miller Class I and II gingival recessions with at least 6 months of follow-up were identified. Data sources included electronic databases and hand-searched journals. The primary outcome variable was complete root coverage (CRC). The secondary outcome variables were recession reduction, clinical attachment gain, keratinized tissue gain, aesthetic satisfaction, root sensitivity, post-operative patient pain and complications.

RESULTS

A total of 794 Miller Class I and II gingival recessions in 530 patients from 25 RCTs were evaluated in this systematic review. CAF was associated with mean recession reduction and CRC. The addition of connective tissue graft (CTG) or EMD enhanced the clinical outcomes of CAF in terms of CRC, while BM did not. The results with respect to the adjunctive use of acellular dermal matrix were controversial.

CONCLUSIONS

CTG or EMD in conjunction with CAF enhances the probability of obtaining CRC in Miller Class I and II single gingival recessions.