A comparative clinical evaluation of acellular dermal matrix allograft and sub-epithelial connective tissue graft for the treatment of multiple gingival recessions.

BACKGROUND: Obtaining predictable and aesthetic root coverage has become an important part of periodontal therapy. Several techniques have been developed to obtain these results with variable outcomes. The aim of this study was to compare and evaluate the effectiveness of acellular dermal matrix allograft (ADMA) and subepithelial connective tissue graft (SCTG) in combination with coronally positioned flap in the treatment of multiple gingival recessions in aesthetic areas.
MATERIALS AND METHODS: Total 10 patients were selected for this study, aged between 18 to 40 years and were randomly assigned to one of the groups ADMA and SCTG. The clinical parameters including probing pocket depth, clinical attachment level, gingival recession, width of keratinized tissue were recorded at baseline and at 6 months after surgery and data was statistically analyzed.
RESULTS: No significant differences in gingival recession reduction were noted between ADMA and gold - standard SCTG. Within limits of this clinical study, the use of ADMA may represent an acceptable alternative to the SCTG for treating gingival recession. The use of ADMA eliminates the need for the palatal donor site thus represents a less invasive surgery for treating multiple gingival recessions.
CONCLUSIONS: These results suggest that ADMA may be a useful substitute instead of subepithelial connective tissue graft for root coverage.

RCT Entities:   Population Interventions Outcomes

INTRODUCTION

Recession of gingival margin remains a highly prevalent problem for its impact on esthetics[1] and dentine hypersensitivity.[23] The patients today are increasingly conscious of personal appearance and much attention has been focused on denuded roots that are exposed during smiling and are unaesthetic.[1] The main indications for root coverage procedures are aesthetic and/or cosmetic demands,[1] followed by the management of root hypersensitivity,[2] or whenever it hampers proper plaque removal.

Obtaining predictable root coverage has been an important part of periodontal therapy. Over the years, several surgical techniques have been described to address the isolated gingival recession, showing a high predictability in terms of root coverage.[4-6] When multiple gingival recessions involving adjacent teeth are present, an approach to address all recession defects at one single surgical time is the first choice. The coronally positioned flap is one of the most effective techniques for the treatment of Miller class I and II gingival recession.[7]

Apart from excellent esthetic results, it is technically simple to perform but the root coverage obtained by this procedure is associated with thin marginal soft tissue recession, at treated sites and thus questions the long-term predictability of coronally positioned flap (CPF) in the treatment of multiple gingival recessions.[8]

Langer and Langer[9] introduced subepithelial connective tissue graft (SCTG) in treating gingival recession, in which connective tissue graft combined with an overlying pedicle graft was used. The SCTG covered by a CPF is a frequently used procedure due to its high predictability.[10] However, this procedure requires a second surgical site that may cause certain degree of discomfort and increase the risk of post operative complications such as pain and hemorrhage. Therefore, the root coverage technique that allows treatment of multiple sites with minimum post-operative morbidity is desirable. In an effort to avoid second surgical site for harvesting the connective tissue graft from the palate, to reduce potential morbidity, and to treat wider array of defects, different biomaterials such as GTR, Emdogain, and acellular dermal matrix allograft (ADMA) with CPF have been tried.

Recently, the use of an ADMA has become an increasingly popular technique, as a substitute for SCTG in treating marginal tissue recession.[1112] In vitro as well as clinical studies suggested that ADMA is an acellular, non-immunogenic scaffold that heals by repopulation and revascularization, rather than through a granulation process maturing to scar.[13] The use of an ADMA has been reported to have a favorable clinical outcome in root coverage procedures with a range of mean root coverage from 86% to 99%.[14-18]

Therefore, the aim of this study was to compare the effectiveness of ADMA and SCTG in combination with CPF in the treatment of multiple gingival recessions in aesthetic areas with the following objectives:

To evaluate the effectiveness of ADMA with respect to root coverage, gain in clinical attachment level and increase in the width of keratinized gingiva.

To evaluate the effectiveness of SCTG in terms of root coverage, gain in clinical attachment level and increase in the width of keratinized gingiva.

To compare the effectiveness of ADMA with SCTG with reference to root coverage and gain in CAL as well as width of keratinized gingiva.

MATERIALS AND METHODS

Study population

Ten systemically healthy patients aged between 18 and 40 years (mean age22.5 ± 8.23 years) with multiple gingival recession defects on labial/buccal surface of teeth were selected from the Outpatient, Department of Periodontology and Implantology, Sharad Pawar Dental College, Sawangi (Meghe), Wardha, Maharashtra, India.

Inclusion criteria

Presence of multiple gingival recession (more than one) defects on the labial or buccal surfaces of the teeth either in maxilla or mandible classified as either Miller's Class I or II[7]

Presence of ≥2 mm gingival recession depth

Presence of width of keratinized gingiva apical to recession ≥2 mm.

Exclusion criteria

Use of tobacco products

Un-cooperative patients

Patients plaque score ≥1 after phase I therapy

History of periodontal surgery in selected gingival recession defects.

The surgical procedures were explained and written informed consent was taken prior to treatment by all the patients. The protocol of the study was approved by the ethical committee of the institution.

Initial therapy

Each patient received initial therapy which included scaling and root planing, polishing, and oral hygiene instructions prior to surgical therapy. Every effort was made to modify the habits that may have been contributed to the recession's defects. Occlusal adjustment was done if needed. Plaque control instructions were given until patients achieved a plaque score of ≤1.

Oral hygiene status

Patient's oral hygiene status was evaluated at baseline, 3 months and at 6 months by using Full mouth Plaque index (FMPI)[19] and gingival health by Full mouth Papillary Bleeding index (PBI).[20]

Clinical parameters

The following clinical parameters were measured for assessment of the results in all the treated cases: probing pocket depth (PPD), clinical attachment level (CAL), gingival recession (GR) and width of keratinized gingiva (WKG) by using the periodontal probe*. All the probing measurements were recorded at maximum depth recession (Mid-facially per tooth) only on teeth to be treated at baseline and at 6 months postoperatively.

Study design and randomization

It was randomly assigned, by the flip of a coin, to one of the treatment groups:

SCTG group: CPF plus SCTG [Figure 1]

Figure 1

(a) Preoperative gingival recession on 23; (b) Horizontal and vertical incisions; (c) Flap reflection with split thickness; (d) SCTG harvested; (e) Surgical template placed on the palate; (f) Flap sutured coronally covering the entire SCTG; (g) Postoperative clinical view after 6 months

ADMA group: CPF plus ADMA [Figure 2]

Figure 2

(a) Preoperative gingival recession on 31 and 41; (b) Horizontal and vertical incisions; (c) Flap reflection with split thickness; (d) ADMA sutured in place; (e) Flap sutured coronally covering the entire ADMA; (f) Postoperative clinical view after 6 months

Surgical procedure

After obtaining local anesthesia, the exposed root surface was planed with hand and ultrasonic instruments.

Recipient site preparation for both the groups

Intrasulcular incision was made on the buccal/labial aspect of the involved tooth. Horizontal incisions were made at right angles to the adjacent interdental papillae, at the level of the cementoenamel junction without interfering with the gingival margin of the neighboring teeth. Two oblique vertical incisions were extended beyond the mucogingival junction and a trapezoidal mucoperiosteal flap was raised up to the mucogingival junction. After this point, a split thickness flap was extended apically, releasing the tension and favoring the coronal positioning of the flap. The epithelium on the adjacent papillae was de-epithelialzed. The root surface was instrumented with curettes and washed with saline solution. The root surfaces were not subjected to any chemical conditioning.

Harvesting of SCTG

A surgical template i.e., sterile tin foil was utilized to obtain the approximate dimensions and shape of the graft. The length of the surgical template was determined by the combined width of the teeth to be covered. Then the surgical template was placed on the palate where it was outlined by a shallow incision. A horizontal incision is made approximately 3 to 4 mm from the gingival margins of the maxillary teeth to the desired width. Vertical incisions were made on either side of the horizontal incision which will further facilitate the removal of the connective tissue graft and aid in wound closure. Primary flap was reflected to expose the underline connective tissue. The graft was excised and trimmed as necessary. The primary flap at the donor site was then placed back to its original position and sutured with 5-0 resorbable sutures†. The surgical site was dressed with periodontal dressing‡.

Placement of SCTG at the recipient site in SCTG group

The SCTG obtained from the donor site was placed at the recipient site at the level of CEJ, covering the entire defect and adjacent recipient bed and sutured to the interproximal papilla with resorbable sutures. The flap was then coronally positioned to completely cover the connective tissue graft and deepithelialized portion of the papilla. The coronal margin of flap were placed slightly coronal to CEJ and stabilized with simple interrupted 5-0 resorbable sutures laterally and continuous sling sutures coronally.

Placement of ADMA at the recipient site in the ADMA group

ADMA§ was hydrated for 10 min in a sterile dish containing saline, according to the manufacturer's instruction. A surgical template i.e., sterile tin foil was utilized to obtain the approximate dimensions of the graft. The ADMA graft was placed in such a way it will cover root surface up to CEJ and apically it will cover the bone at least 2-3 mm. The basement side was placed adjacent to bone and tooth and connective tissue side was placed facing the flap. The coronal-lateral border of ADMA was sutured to lingual gingival tissue with 5-0 resorbable sutures. The flap was then coronally positioned and sutured to completely cover the ADMA.

Subsequently, periodontal dressing was placed over the surgical site in both the groups.

Post-surgical care

After surgery, NSAID¶ Ibuprofen 200 mg + Paracetamol 400 mg, t.i.d. and systemic antibiotic Amoxicillin** 500 mg t.i.d. were prescribed for 7 days post-surgically. All patients were instructed not to brush around the surgical sites for the first 30 days after surgery. During this period, the plaque control was achieved with a 0.12% Chlorhexidine gluconate†† solution rinse twice daily. After 14 days, the periodontal dressing and sutures were removed. All the patients were examined weekly for first month and once a month for next 3 months for supragingival scaling and oral hygiene instructions until the end of the study. All patients were recalled after 6 months and clinical parameters were recorded.

Statistical analysis

In the present study, the mean and standard deviation (Mean±SD) values were calculated for all the parameters. The mean data was analyzed for the statistical significance by the standard statistical method. Students paired t-test was used to compare data from baseline to those at 6 months for each group. Comparisons between treatment groups at baseline and 6 months were accomplished with student's unpaired t-test. Comparisons of the PI and PBI at baseline, 3 months and 6 months were made by students paired t-test. If the probability value (P) was more than 0.05, the difference observed was considered non-significant and if less than 0.05, it was considered significant.

RESULTS

During the course of the study, wound healing was uneventful. The periodontal dressing remained in place until the first post-operative appointment. There were no postoperative complications in any patient. None of the selected patients dropped out before the termination of the study and all the patients were satisfied with the results.

Clinical indices

The decrease in the mean Plaque index score and the mean Papillary bleeding index score at baseline and 6 months post-operatively in both groups indicated improvement in gingival condition throughout the study.

Clinical outcomes at 6 months post-operatively:

Results indicate no significant difference between the two groups at baseline and at 6 months post-operatively in term of reduction in depth of GR, PPD, CAL gain, and WKG showed a significant increase in both groups post-operatively [Table 1]. Additional information regarding the mean percent root coverage was calculated. Mean percent root coverage in SCTG group was 97% and in ADMA group was 94% indicating no significant difference in mean percent root coverage [Table 2].

Table 1

Comparison of clinical parameters between SCTG and ADMA groups at baseline and 6 months

Table 2

Mean reduction of gingival recession with percentage of root coverage in individual patients in SCTG and ADMA groups

DISCUSSION

When multiple gingival recession defects affecting adjacent teeth in aesthetic areas of the mouth are present, they should all be treated at the same time to achieve the best aesthetic results.[21] Therefore, this study was carried out to evaluate the effectiveness of Subepithelial connective tissue graft (SCTG) and Acellular dermal matrix allograft (ADMA) with coronally positioned flap in the treatment of multiple gingival recession in one sitting.

A total of 20 buccal/labial recession defects in 10 patients were treated. There was no sign of allergy, infection or any other complication in any patient after the use of ADMA graft, which indicates that the product ADMA was well tolerated.

The clinical outcomes of various forms of surgical interventions are influenced by general level of oral hygiene. In this case series, both mean plaque index (PI) and papillary bleeding index (PBI) were significantly reduced at 6 months as compared to baseline. The results presented here indicate that treatment modalities, SCTG, and ADMA group showed good improvement in the studied clinical parameters with respect to baseline and at 6 months [Table 1]. Successful root coverage was found in both the treated groups with mean percent root coverage in the SCTG group being 97% and in the ADMA group was 94% [Table 2]. These findings are in agreement with previously reported studies. Hirsch et al.[16] observed 99% root coverage for SCTG group and 95% for ADMA group. Rahmani et al.[11] also observed mean root coverage of 70% for SCTG and 70% for the ADMA group.

In the present study, the mean gain in clinical attachment level in both the groups was 2.7 mm. The type of healing obtained between the ADMA and previously denuded root surface can only be speculated on, since no histological evaluations were available. Based on the reports of ADMA, matrix would revascularize via preserved vascular channel and that it would integrate into the host tissue.[2223] At the same time, ADMA may also act as a barrier equivalent to selective cell repopulation membrane, thus encouraging periodontal-guided tissue regeneration. The observed clinical changes probably represent a combination of new connective tissue attachment in the apical half of the defect and the presence of long junctional epithelial attachment in the coronal half.[24] In the case of connective tissue graft, based on histological evidence, healing has been shown to be mediated through a long junctional epithelium along the major portion of the root with an extremely limited area of new attachment and bone formation at the base of the recessions.[25] Although a new connective tissue attachment mostly fails to form in the entire depth of the defect in previous histological studies on ADMA and SCTG, the treatment procedures used in the present case series did not result in formation of a deep periodontal pocket.

In the present study, we observed an increase in the width of keratinized gingiva in both the groups. The mean increase in the width of keratinized gingiva in the SCTG group was 1.2 mm and 1 mm in the ADMA group. Similar observations have been made by Hirsch et al.[16] and Haim et al.[26] in a clinical trial comparing SCTG and ADMA with a coronally positioned flap. In a comparative study on the effectiveness of ADMA to increase width of attached gingiva, Wei et al.[27] reported that ADMA produced a lesser extent of attached gingiva in comparison to SCTG. They believed that the difference could be attributed due to considerable shrinkage of ADMA during the healing phase.

Our study presented two-main limitations: one was the 6 month short-term evaluation (since creeping attachment occurs highest during 9-12 months, which may further improve the root coverage[28]) and the second was the lack of histological evaluation.

CONCLUSIONS

The root coverage obtained by both procedures although satisfactory, clinical relevance in terms of patient's satisfaction was especially with the use of ADMA as most of the patients were treated with aesthetic request. One of the advantage of ADMA is that the need for palatal donor material is eliminated, which reduces post-operative morbidity. In addition, it provides an unlimited supply of graft material thus permitting multiple site root coverage that can be extended for a sextant, quadrant, or even a full mouth arch at one time.