Novel Membrane for the Treatment of Multiple Gingival Recession Defects-RCT

Introduction

Periodontal plastic surgery is used to treat a wide variety of procedures like gingival augmentation, coronal or apical root coverage, crown lengthening, removal of abnormal frena, prevention of ridge collapse associated with tooth extraction and correction of mucosal defects around implants.¹ Anatomic features includes bony dehiscence, thickness of the alveolar mucosa, muscle pull, position and anatomy of teeth in the dental arch, thin gingival biotype, buccal prominence of teeth, lack of keratinized tissue, abnormal frenum attachment, vigorous brushing or chronic gingival inflammation can contribute to gingival recession.² Defect number, defect dimensions, defect site, soft tissue anatomy, and tooth location factors play a critical role in determining the success of root coverage procedures.³

Treatment^4,5,6 of multiple gingival recession includes the use of a partial or full thickness flaps with various soft tissue grafts such as free gingival grafts (FGG) or sub-epithelial connective tissue graft (SCTG) with various types of Flaps.^7,8 The gold standard in the treatment for gingival recession is coronally advanced flap (CAF) done with connective tissue graft (CTG).⁹ Commercially available materials for root coverage have been explored from expanded Poly Tetra Fluoro Ethylene, Gore-(m-Tex), polyglactin, collagen membranes like BioMend, resolute, b=Bio Gide, colla tape, Aloderm, etc to collagen matrix such as human amniotic membrane, etc.^10,11

Ossix® Volumax is a collagen matrix that is sugar cross-linked using Glymatrix technology. It is a bioprogrammed thick and volumizing scaffold, easy to use. It expands when wet and has excellent handling properties.¹² Ossix® Volumax can undergo rapid ossification. In a case report using platelet concentrate, impregnated collagen sponge (Ossix®) has shown encouraging results.¹³ De novo bone in an alveolar ridge augmentation procedure using Ossix® Volumax has been demonstrated.¹⁴

Materials and Methods

Patients aged 22 to 54 years old exhibiting adjacent Millers class I and II gingival recession defects having a total of sixty gingival recession sites participated in the study. Patients satisfying the inclusion criteria, at least two or more teeth with multiple adjacent gingival recession sites with a full mouth plaque score ≤10% and full mouth bleeding score<10% and exclusion criteria, history of tobacco smoking and gingival biotype less than 0.8 mm were assessed. Patients were informed about the nature of the study and informed consents were obtained. This clinical trial followed Consolidated Standards of Reporting Trials (CONSORT) criteria revised in 2010. (Figure 1) The Clinical Trials.gov.in identity number is NCT04195737. Institutional Ethical Committee and Review Board (KCDS/Ethical Comm/008/2019- 2020) affiliated with Rajiv Gandhi University of Health Sciences has approved the study procedure.

The study had 80% confidence limit and 90% power with a total of sixty gingival recession defects. Calculation was obtained using SPSS Version 10.5(IBM), for data analysis. Computer-generated randomization sequence was obtained by an assistant (PP). Recession defects (n=60) were randomly assigned to either the test or control group. Post Hoc Scheffe‘s test was used to calculate mean standard deviation of the study population. For intra-group assessment, one-way analysis of Variance (ANOVA) was used to test the difference between time points. Gingival recession width (GRW), Gingival recession depth (GRD), mean root coverage (MRC), Root Coverage Esthetic Score System (RES), complete root coverage (CRC), probing pocket depth (PPD), keratinized tissue width (KTW) and attachment loss (CAL) were compared using Student ‘t’ test. P value < 0.05 was considered statistically significant.

GRD was measured as the distance from the CEJ to the gingival margin, GRW was measured as the distance between the mesial gingival margin and the distal gingival margin. Esthetic assessment was according to Root Coverage Esthetic Score System and CRC was measured at 6 weeks, 3 months, and 6 months and considered as primary clinical outcome. Parameters were recorded using a periodontal probe (Hu-Freidy) with an occlusal stent. Probing pocket depth (PPD), Clinical attachment level (CAL), Width of keratinized tissue (KTW), Plaque Index (PI), Gingival Index (GI) and Gingival Bleeding Index (GBI) were assessed as secondary outcomes. 

Thirty defects received Ossix® Volumax (Figure 2), (MCAF with VCMX) were considered as Test group and the 30 remaining gingival recession defects received SCTG (MCAF with SCTG), were considered as a control group.

All defects were treated with a modified coronally advanced flap (MCAF) procedure a design as proposed by Zucchelli and De Sanctis.¹⁵ Extension of the flap was decided on the number of recession defects at both the mesial and distal end of the gingival recession (Figure 3). Interdental papilla tip was not reflected. Recession defects were treated with sub-marginal oblique incisions then connected with intrasulcular incisions along the mesial and distal gingival margins to finish designing the flap surgical papilla. The remaining soft tissue of the anatomic interdental papillae adjacent to sub-marginal incision was de-epithelialized. The full thickness flap apical recession defects and again a spilt thickness flap apically approximately 3 mm of periosteum was exposed (split-full-split) to mobilise flap coronal advancement. For the test group, Ossix® Volumax (VCMX) was placed in the recipient gingival recession defect and sutured. For the control group, sub-epithelial CTG was harvested using a parallel incision technique as described by Langer and Langer. All graft was sutured to the periosteum with (4-0 vicryl, Ethicon) sutures. Coronal advancement of the flap was done without tension with its margin located on the enamel and the wound closure was done using sling sutures. Surgical sites were protected with non-eugenol dressings (Coe-pack, GC America).

Post-operative pain and edema was controlled with analgesics (non-steroidal anti-inflammatory drugs and antibiotics (Cap, Amoxicillin 500 mg thrice daily for seven days). Patients were reinstructed in mechanical cleaning using a soft toothbrush and coronally directed roll technique of brushing for 1 month. The instructions were reinforced, in addition to light debridement with ultrasonic scaling at 2 and 4 weeks after suture removal and subsequently every 2 months until 6 months.

Results

Preoperative comparison of the test and control groups (Table 1) showed that the study parameters were significantly different (P <0.05) between the two groups. Healing was noted to be uneventful in all cases of clinical parameters comparisons are shown in Tables 1- 4.

Mean root coverage was 3.33 mm (SD = 0.49) in the control group and 3.90 mm (SD = 0.99) in the test group (P = 0.077). While mean root coverage (Graph 1) was found to be significantly better in the test group, complete root coverage scores were not statistically different between the two groups (P=.0833).

Discussion

Stability over time, complete root coverage (CRC), and concomitant increase in width and thickness of keratinized tissue of Sub-epithelial CTG (SCTG) has made it as the gold standard for the treatment of gingival recession.^15,16 However, because the graft must be harvested from the palate, the approach necessitates a second, more complex surgical procedure, which increases patient morbidity and surgical chair time.¹⁷ Furthermore, the amount of donor tissue available is limited. Because of these limitations of SCTG, physicians have developed other biomaterials for root-covering procedures. Researchers have been focusing on developing new alternatives to SCTG.

In our study, collagen matrix using collagen cross-linking technology has been used. Ossix® Volumax (VSCM) is one such biodegradable and biocompatible collagen membrane designed for use in guided bone regeneration and tissue regeneration procedures. Here, collagen was extracted from porcine tendons in an approved, controlled standardized procedure to prepare a collagen scaffold of 1.5 - 2 mm thick, which expands when wet and adheres to bone. The greatest advantage of Ossix® Volumax was that, if exposed it resists degradation which is allowed to occur slowly over a period of up to 6 months in its progress towards mineralisation and ossification. In the regenerative procedure, it restores the lost volume and provides a favourable emergence profile. When a collagen scaffold is placed in one or two layers, it obviates the need for a bone substitute material or a SCTG, although adding a bone substitute material is a valid option when indicated.¹⁸ GBR using VSCM has achieved a successful results for soft tissue augmentation around teeth and dental implants.^19,20 This study is the first of its kind for the treatment of multiple recession defects. Previously, Kontovazainitis. placed Ossix membrane (ColBar Life Science) and Platelet Concentrates (PCG) using coronally advanced Flap (CAF) for treatment of MADRs.¹³ There is very little systematic review addressing MARDs, when compared to those analysing localized recession. Similar to our study, Graziani concluded about limited evidence available for treatment for multiple gingival recession coverage.²¹

Lai et al addresses root coverage procedures for multiple recessions.²² Contrary to our study, this review concludes collagen matrix (CM) is effective but less satisfactory than CTG in the management of MARDs. The mean Root Coverage (MRC) noted in Lai’s review was 71% for CM as opposed to 90% for SCTG. Similarly, in our study, MRC noted for the Volumax group was 60% and for SCTG was 85% at 6 months. The CRC (Test 80%) of our study is in disagreement with Lai’s review, thereby showing superior result for Ossix® Volumax.

Reduction in gingival recession depth (GRD) from baseline to 6 months in both test (2.6 mm) and control study groups (2.53 mm) was noted. Highly significant recession reduction was seen in both groups at all interval time. Meta-analysis shows greater recession depth reduction with mCAF and CTG.²³ Our study showed contrary results to this, thereby suggesting mCAF with Ossix® Volumax had highly significant recession depth reduction. In our study, complete root coverage was higher in the test group (80%) when compared to the control group (60%). Root coverage was lower in the test group (60.80%) in comparison to the control group (85.12%). Reduction in gingival recession width (GRW) in the test group was 3.4 mm as compared to control group with 2.33 mm. The percentage reduction in width (GRW) achieved was greater for the test at all intervals (P<0.001) between the two groups. Hägewald et al., found 2.9 mm of recession reduction in Emdogain and CAF groups with 80% root coverage at 12 months after therapy.²⁴ Kontovazainitis reported 80% root coverage for Platelet Concentrate group (PCG) at 8 months.¹³ Similar to these studies, our results showed recession depth reduction and width reduction with complete root coverage (CRC) for Ossix® Volumax group as 80% at 6 months post therapy.

Esthetic outcome at 6 months did not show a statistically significant difference but showed enhanced gain in KTW. Root coverage esthetic score was 5.99/10 for the test and 6.71/10 for the control group was noted. Both groups observed satisfactory RES (esthetic score), similar to those obtained by Atieh and Steffanani.^25,26 The overall PD reduction achieved at 6 months was 1.32 mm in the control group and 1.43 mm in the test group. There was no statistical significance between the groups or within the time interval. These results are in accordance with Sangiorgio (0.18 mm).²⁷ Attachment gain (CAL) of 2.33 mm for the control group and 2.97 for the test group was noted. The CAL gains between both groups were similar. CAL gain over a period of 6 months in both groups was statistically significant. The present study was similarly in accordance with Castro et al.²⁸ Here, the parameters PI, GI, and GBI also showed no statistically significant difference in both groups.

The limitation of our study was the smaller sample size and short-term follow-up time. A radiographic measurement (CBCT) to assess the real volume can be suggested to assess at 3 months and 6 months. Among clinical parameters, gingival thickness was not assessed. The outcomes were assessed only on clinical parameters, which were in exact nature can only be evaluated histologically. Our clinical trial is an initial attempt to extrapolate these findings.

As Ossix, Volumax is a volume-stable collagen matrix with clinically acceptable aesthetics. Using VSCM, good clinical parameters have been achieved. Volumax reduced surgical time compared to SCTG and this reduction was expected to reduce postoperative discomfort and promote wound healing.^29,30

The use of Collagen Matrix (CM) offered a less traumatic and predictable alternative to root coverage in MARDs compared to SCTG. VSCM signifies an alternative to SCTG by reducing surgical time and less postoperative morbidity. Lack of need for a donor area, shorter surgical time, shorter time to recovery, and better patient perception are the potential advantage of Ossix® Volumax in the treatment of multiple gingival recessions.

Conflict of interest

Nil

Acknowledgement

We would like to acknowledge all study participants and our Institutional Ethical Committee and review board (KCDS/Ethical Comm/008/2019-2020).