A Comparative Evaluation of Silk Suture and Cyanoacrylate Adhesive in the Stabilization of Free Gingival Graft Harvested with Erbium: Yttrium-Aluminum-Garnet Laser: A Clinical Study.

BACKGROUND: The most common technique for gingival augmentation is free gingival graft (FGG). The aim of this study is to clinically compare the efficacy of FGG harvested with erbium: yttrium-aluminum-garnet (Er: YAG) laser stabilized with 5-0 silk suture in comparison to N-butyl-2-cyanoacrylate tissue adhesive in increasing the width of keratinized gingiva (WK) for the management of Miller's Class I and II gingival recession.
METHODOLOGY: Forty-eight gingival recession defects were divided into two Groups I and II. Group I sites were treated with FGG harvested using Er: YAG laser stabilized with 5-0 silk suture and Group II sites were treated with FGG harvested using Er: YAG laser stabilized with N-butyl-2-cyanoacrylate tissue adhesive. Clinical parameters such as gingival recession depth, clinical attachment level (CAL), gain in gingival tissue thickness, and WK were recorded at baseline and 3 and 6 months postoperatively.
RESULTS: A significant reduction in gingival recession defects, gain in CAL, increase in WK, and gain in gingival tissue thickness were observed in both the groups. Intergroup comparison of gingival recession defects, CAL, WK, and gingival tissue thickness yielded nonsignificant differences.
CONCLUSION: Within the limits of this study, it can be concluded that both 5-0 silk suture and n-butyl-2-cyanoacrylate were equally efficacious in the stabilization of FGG. N-butyl-2-cyanoacrylate was easy to apply, consumed less operating time, and had no adverse effect. Hence, cyanoacrylate can be used as an alternative to suture in stabilization of FGG. Copyright:

INTRODUCTION

Gingival recession affects almost all middle- and older-aged people to some degree.[1] Gingival recession is defined as the displacement of gingival margin apical to cementoenamel junction.[2] It results in root exposure which leads to clinical problems such as hypersensitivity, root caries, cervical abrasions, difficulty in plaque removal, and unpleasant esthetics.[3] For a patient, gingival recession usually creates an esthetic problem, especially when it affects the anterior teeth, and anxiety about tooth loss due to progressive destruction.[4]

The treatment of gingival recession with periodontal plastic surgery procedures is a feasible option in the present day. The ultimate goal of these periodontal procedures is to accomplish complete root coverage leading to pleasant esthetic outcomes.[5] The most classical clinical procedure in mucogingival surgery is free gingival grafting, which was introduced in 1968.[6] Free gingival graft (FGG) is widely used to increase the dimensions of attached gingiva.[7] One of the factors that are involved in the tissue healing process is the immobilization of gingival graft which leads to the success of grafting.[8]

Improper immobilization may cause a delay in the tissue revascularization process and eventually leads to tissue necrosis. Suturing is the conventional technique for stabilization of FGG at recipient site. However, it should be certain that the graft is correctly positioned and is immobile. In order to prevent any damage to the graft, the number of sutures must be reduced to minimum.[8] In 1949, Ardis synthesized and introduced tissue adhesives so as to eliminate the use of sutures. In 1959, Coover et al. chemically analyzed and examined the properties of cyanoacrylate adhesives and proposed their application in surgical procedures.[9] Hoexter in 1979 introduced the sutureless FGG technique. He gave credence to the hypothesis that even without the use of sutures, it is possible to achieve immobilization, asepsis, and hemostasis but only if the graft has been positioned and fixed correctly.[10]

To the best of our knowledge, only a few studies had compared the stabilization of FGG with suturing and tissue adhesive.[11] In this study, it was planned to compare 5-0 silk suture and n-butyl-2-cyanoacrylate adhesive in stabilization of FGG harvested with erbium: Yttrium-aluminum-garnet (Er: YAG) laser for augmentation of keratinized tissue in management of Class I and II gingival recession.

METHODOLOGY

In this 6-month follow-up study, randomized, double-blind, clinical trial, a total of 48 systemically healthy subjects (26 males and 22 females with mean age of 29.4 years) with Miller's Class I and II gingival recession defects, reporting to the Outpatient Department of Periodontology and Oral Implantology at Genesis Institute of Dental Sciences and Research, Ferozepur, Punjab, India, were included in the study. The study was conducted from March 2015 to May 2016. After ethical approval of research protocol from the Institutional Ethical Committee and Review Board, all participants were verbally informed about the study protocol and written informed consent was obtained.

Patients with history of any systemic disease, taking medication which could affect periodontal therapy outcomes, smokers, pregnancy and lactating females, poor oral hygiene, mobile teeth, and cervical caries were excluded.

Presurgical protocol

A full-mouth supra- and subgingival scaling and root planing procedure was performed under local anesthesia. Six weeks after Phase I therapy, periodontal evaluation was done to confirm the desired sites for the study. Selected subjects were divided into two groups by coin flip method.

Clinical measurements

Clinical parameters recorded before surgical procedures included the following: (1) plaque index (PI), (2) gingival index (GI), (3) gingival recession depth (RD), (4) clinical attachment level (CAL), (5) width of keratinized gingiva (WK), and (6) gingival tissue thickness. All the clinical parameters were measured at baseline and 3 and 6 months postoperatively by an evaluator who was masked to the surgical procedure performed on patients.

Surgical procedure

During surgery, patients and the surgical team wore special laser eyeglasses to prevent injury. An Er: YAG laser was used to prepare the recipient area for the FGG, using the 3-W, 300-mJ, 10-Hz, and very long pulse (1000 μs) mode. Root surface modification was also performed with the Er: YAG laser, using the 1.20-W, 120-mJ, 10-Hz, and medium-short pulse (100 μs) mode. De-epithelization of the mucosa was performed with a scanning movement to prepare the recipient site. The tip was directed perpendicular to the tooth's long axis to avoid contact with the enamel. After measuring the recipient site with a UNC-15 probe, the measurements for harvesting graft were outlined on palate with the Er: YAG laser. The dissection was done with a no. 15 blade, kept parallel to the epithelial outer side of the graft. After excision of the graft, gauze moistened with saline was applied to the donor area to achieve hemostasis, and the harvested graft was immediately placed on the recipient area.

In Group I, FGG was sutured with 5-0 silk sutures; one suture was inserted on both the distal and mesial edges, and a suspensory recipient suture was used for graft stabilization, without penetrating the graft. The graft was firmly held in place using digital pressure for 5 min with gauze moistened with saline.

In Group II, FGG was stabilized with n-butyl-2-cyanoacrylate. Gentle pressure was applied to the graft for 5 min and then cyanoacrylate was applied using its special 0.25 ml pipette so that there was approximately 2 mm width of adhesive all along the graft borders. Excess drops flowing over were cleaned with gauze moistened with saline. It was then allowed to stand for 1–2 min to adhere the graft to the recipient site. A periodontal dressing was applied to protect the surgical area for 14 days.

Postoperative care

Suitable antibiotics and analgesics (500 mg amoxicillin, four times daily for 5 days, and 800 mg ibuprofen, three times daily) were prescribed, along with chlorhexidine digluconate rinses (0.12%) twice daily for 2 weeks. Periodontal dressing and sutures were removed 2 weeks postoperatively. Surgical wounds were gently cleansed with 0.12% chlorhexidine digluconate. Each patient was reinstructed in proper oral hygiene measures.

Statistical analysis

The collected data were put to statistical analysis using the Statistical Package for the Social Sciences (SPSS) software (SPSS Inc., Chicago, IL, USA, version 23.0 for Windows). The gingival recession, WK, gingival tissue thickness, and CAL were tested for normalcy by using Kolmogorov test. The gingival recession was compared by using Mann–Whitney U-test between the groups and mean change in the gingival recession within the group was compared by Wilcoxon rank-sum test. The WK, gingival tissue thickness, and CAL were compared by using unpaired t-test between the groups and mean change within the groups was compared by using paired t-test. P < 0.05 was considered statistically significant.

Measurements were recorded by a single examiner, and surgical procedure was done by the same operator. All patients completed the study and fully complied with the recall program.

RESULTS

Preoperative and postoperative parameters at 3 months and 6 months, ascertained clinically, for Group I and Group II are presented in Table 1.

Table 1

Summary of values of mean and standard deviation of plaque index, gingival index, gingival recession depth, clinical attachment level, width of keratinized gingiva, and gingival tissue thickness at different study intervals for Group I and Group II

Clinical parameters (n=12)	Mean±SD
	Group I			Group II
	Baseline	3 months	6 months	Baseline	3 months	6 months
PI	1.48±0.41	1.55±0.59	1.63±0.52	1.46±0.45	1.53±0.48	1.60±0.55
GI	0.31±0.28	0.30±0.26	0.36±0.24	0.52±0.31	0.48±0.34	0.49±0.40
Gingival recession depth (mm)	3.50±1.38	1.12±1.20	0.58±0.73	2.92±0.99	1.33±1.07	0.87±0.71
Clinical attachment level (mm)	5.08±0.79	2.75±0.58	2.08±0.66	4.67±0.77	2.62±0.48	1.83±0.38
Width of keratinized gingiva (mm)	1.67±0.65	2.83±0.80	3.04±0.83	1.92±0.66	2.75±0.58	2.83±0.44
Gingival tissue thickness (mm)	0.67±0.06	2.05±0.09	2.23±0.09	0.72±0.03	2.06±0.04	2.27±0.08

SD: Standard deviation, N: Number of patients, GI: Gingival index, PI: Plaque index

Plaque index

Changes in mean PI scores at different time intervals in both the groups are shown in Table 2. From baseline to 3 and 6 months, nonsignificant difference in PI score was observed in both the groups. Mean changes in PI scores in intergroup comparison at different time intervals yielded statistically nonsignificant results (P > 0.05).

Table 2

Mean change and standard deviation of plaque index scores in Group I and Group II and their comparison at different time intervals

Time interval	Group	Mean change±SD	P	S	Mean difference	P	S
Baseline to 3 months	I	0.07±0.54	0.54 (>0.05)	NS	0.03	0.42 (>0.05)	NS
	II	0.07±0.56	0.55 (>0.05)	NS
Baseline to 6 months	I	0.15±0.54	0.79 (>0.05)	NS	0.02	0.38 (>0.05)	NS
	II	0.14±0.64	0.61 (>0.05)	NS
3 months to 6 months	I	0.08±0.43	0.36 (>0.05)	NS	0.02	0.38 (>0.05)	NS
	II	0.04±0.45	0.32 (>0.05)	NS

NS: Nonsignificant, SD: Standard deviation

Gingival index

Changes in mean GI scores at different time intervals in both the groups are shown in Table 3. From baseline to 3 and 6 months, nonsignificant difference in GI score was observed in both the groups. Mean changes in GI scores in intergroup comparison at different time intervals yielded statistically nonsignificant results (P > 0.05).

Table 3

Mean change in gingival index score in Group I and Group II and their comparison at different time intervals

Time interval	Group	Mean change±SD	P	S	Mean change	P	S
Baseline to 3 months	I	0.01±0.28	1.01 (>0.05)	NS*	0.03	0.31 (>0.05)	NS*
	II	0.04±0.39	0.48 (>0.05)	NS*
Baseline to 6 months	I	0.05±0.26	0.22 (>0.05)	NS*	0.02	0.13 (>0.05)	NS*
	II	0.03±0.39	0.51 (>0.05)	NS*
3 months to 6 months	I	0.06±0.29	0.11 (>0.05)	NS*	0.05	0.10 (>0.05)	NS*
	II	0.01±0.58	0.32 (>0.05)	NS*

*Nonsignificant (>0.05). SD: Standard deviation

Gingival recession depth

Mean change in gingival RD at different time intervals in both the groups is shown in Table 4. Mean change in gingival recession from baseline to 3 and 6 months was found to be statistically significant (P = 0.0001). However, the mean change in gingival recession was higher in Group I compared to Group II. The mean change in gingival recession from 3 months to 6 months was also found to be significant (P = 0.01) in both the groups.

Table 4

Mean change in recession depth in Group I and Group II and their comparison at different time intervals

Time interval	Group	Mean change±SD	P	S	Mean difference	P	S
Baseline to 3 months	I	2.37±0.56	0.0001	S	0.79	0.12	NS
	II	1.58±0.51	0.0001	S
Baseline to 6 months	I	2.91±0.84	0.0001	S	0.87	0.06	NS
	II	2.04±0.49	0.0001	S
3 months to 6 months	I	0.54±0.62	0.01	S	0.08	0.11	NS
	II	0.46±0.45	0.01	S

S: Significant, NS: Nonsignificant, SD: Standard deviation

Intergroup comparison of mean change in gingival RD at different time intervals yielded statistically nonsignificant difference when values were compared from baseline to different study intervals (P > 0.05).

The root coverage percentage of RD of Group I and Group II at different time intervals is depicted in Table 5. When 3-month and 6-month results were compared to baseline, there was a statistically significant reduction (P < 0.05) in gingival RD for both the groups.

Table 5

Mean root coverage percentage of recession depth of Group I and Group II at different time intervals

Time interval	Group	Mean (%)	P	S
Baseline to 3 months	I	73.6	0.0001	S†
	II	59.6	0.0001	S†
Baseline to 6 months	I	86.4	0.0001	S†
	II	73.4	0.0001	S†

†Statistical significance

Clinical attachment level

Changes in mean CAL at different time intervals in both the groups are shown in Table 6. In Group I, a gain in mean CAL from baseline to 3 months was 2.33 ± 0.61 mm (statistically significant, P < 0.05), from baseline to 6 months was 3.00 ± 0.95 mm (statistically significant, P < 0.05), and 0.66 ± 0.61 mm from 3 to 6 months which was statistically significant (P < 0.05). A gain of 2.29 ± 0.81 mm in mean CAL was recorded in Group II from baseline to 3 months (statistically significant, P < 0.05). A gain of 2.83 ± 0.93 mm (statistically significant, P < 0.05) from 3 to 6 months and 0.79 ± 0.58 mm (statistically significant P < 0.05) thereafter from 3 to 6 months was recorded.

Table 6

Mean change in clinical attachment level in mm in Group I and Group II and their comparison at different time intervals

Time interval	Group	Mean change±SD (mm)	P	S	Mean difference	P	S
Baseline to 3 months	I	2.33±0.61	0.0001	S	0.04	0.67	NS
	II	2.29±0.81	0.0001	S
Baseline to 6 months	I	3.00±0.95	0.0001	S	0.17	0.97	NS
	II	2.83±0.93	0.0001	S
3 months to 6 months	I	0.66±0.61	0.003	S	0.13	0.47	NS
	II	0.79±0.58	0.001	S

S :Significant, NS: Nonsignificant, SD: Standard deviation

Intergroup comparison of mean change in CAL at different time intervals yielded statistically nonsignificant difference [Table 6].

Width of keratinized gingiva

Mean change in WK at different time intervals in both the groups is shown in Table 7. In Group I, a gain in mean WK from baseline to 3 months was 1.16 ± 0.53 mm (P < 0.05), from baseline to 6 months was 1.37 ± 0.43 mm (P < 0.05), and from 3 months to 6 months was 0.20 ± 0.25 mm (P < 0.05). A gain of 0.83 ± 0.32 mm (P < 0.05) from baseline to 3 months, 0.91 ± 0.46 mm (P < 0.005) from baseline to 6 months, and 0.08 ± 0.41 mm (P > 0.05) between 3 months and 6 months was observed in Group II.

Table 7

Mean change in width of keratinized gingiva in mm in Group I and Group II and their comparison at different time intervals

Time interval	Group	Mean change±SD (mm)	P	S	Mean change	P a	S
Baseline to 3 months	I	1.16±0.53	0.0001	S	0.33	0.19	NS
	II	0.83±0.32	0.0001	S
Baseline to 6 months	I	1.37±0.91	0.0001	S	0.46	0.07	NS
	II	0.91±0.46	0.0001	S
3 months to 6 months	I	0.20±0.25	0.01	S	0.12	0.79	NS
	II	0.08±0.41	0.50	NS

S: Significant, NS: Nonsignificant, SD: Standard deviation

Intergroup comparison yielded statistically nonsignificant difference in WK (P > 0.05) from baseline to 3 months and from baseline to 6 months. Statistically nonsignificant difference was observed from 3 months to 6 months.

Gingival tissue thickness

Changes in gingival tissue thickness at different time intervals in both the groups are expressed in Table 8. In Group I, a gain in mean gingival thickness from baseline to 3 months was 1.38 ± 0.07 mm (P < 0.05), from baseline to 6 months was 1.55 ± 0.08 mm (P < 0.05), and from 3 months to 6 months was 0.17 ± 0.06 mm (P < 0.05). A gain of 1.33 ± 0.05 mm (P < 0.05) from baseline to 3 months, 1.54 ± 0.10 mm (P < 0.05) from baseline to 6 months, and 0.21 ± 0.07 mm (P < 0.05) between 3 months and 6 months was observed in Group II.

Table 8

Mean change in gingival tissue thickness in mm in Group I and Group II at different time intervals

Time interval	Group	Mean change±SD (mm)	P	S	Mean change	P	S
Baseline and 3 months	I	1.38±0.07	0.0001	S	0.05	0.08	NS
	II	1.33±0.05	0.0001	S
Baseline and 6 months	I	1.55±0.08	0.0001	S	0.01	0.76	NS
	II	1.54±0.10	0.0001	S
3 months and 6 months	I	0.17±0.06	0.0001	S	0.04	0.23	NS
	II	0.21±0.07	0.0001	S

S: Significant, NS: Nonsignificant, SD: Standard deviation

Intergroup comparison of mean change in gingival tissue thickness at different time intervals yielded statistically nonsignificant differences.

DISCUSSION

Gingival recession is an intriguing and complex phenomenon due to which patients are concerned about sensitivity and poor esthetics. In the current practice of periodontics, clinicians face the challenge of not only addressing biological and functional problems present in the periodontium, but also providing therapy that result in acceptable esthetics.[12]

Insufficient width of attached gingiva is a major mucogingival problem when the existing attached gingiva does not enable effective patient plaque control. Existing clinical and histological data suggest that any dimensions which enable maintenance of healthy periodontium can be regarded as adequate rather than a certain width in millimeters.[1314] FGG is widely used to increase the dimensions of attached gingiva.[7] Its autogenous character, maintenance of keratinization, predictability of surgical outcomes, and ease of technique together with the possibility of implementation in a group of teeth lead FGG to be accepted as the gold standard to increase the dimensions of attached gingiva.[14]

So far, a concerted effort has been made in the field of root conditioning to improve the outcome of regenerative periodontal therapies by favoring the attachment of the regenerated periodontal structures. Recently, the application of laser irradiation to periodontal therapy is being investigated. Advantages of laser include surface sterilization, good hemostasis, reduced bleeding intraoperatively, patient comfort, and less postoperative pain. Studies have demonstrated that the Er:YAG laser has a considerable ability to remove lipopolysaccharides from root surfaces and also to facilitate the removal of the smear layer after root planing.[151617] Thus, in this study, the Er:YAG laser was chosen as it can be used both on soft tissue for de-epithelization and on hard tissue for root surface modification.

Factors disrupting the continuity of graft nutrition play a major role in graft shrinkage. According to Sullivan and Atkins, graft thickness, atraumatic surgical technique, and quick stabilization of the graft are vital to protect graft vessels from damage and dehydration, thereby decreasing the shrinkage.[6] Suture technique is also highly important for minimizing trauma to the graft tissue. Factors, which act during stabilization of FGG, affect “avascular plasmatic circulation” and eventually enhance graft shrinkage. Therefore, sutureless stabilization techniques could help to decrease or even prevent graft shrinkage and adhesives may be a method for achieving this goal.

Cyanoacrylates are used as tissue adhesives in pediatric surgery, general surgery, and dentistry. N-butyl-2-cyanoacrylate is a bacteriostatic, biodegradable, hemostatic cyanoacrylate with a long half-life and good tissue compatibility.[18] It can adhere in moist environment and is available in a formulation appropriate to be used in the oral cavity.

Thus, in this study, it was planned to compare 5-0 silk suture with n-butyl-2-cyanoacrylate adhesive in stabilization of FGG harvested with Er: YAG laser for augmentation of keratinized tissue in management of Class I and II gingival recession.

Statistically nonsignificant difference in PI was observed over the study intervals in both the groups. These results may be attributed to reinforcement of oral hygiene and regular monitoring of the patient at different study intervals and also elucidate successful patient motivation and compliance to the instructions rendered. Results of the present study are in compliance to the study done by Hangorsky and Bissada[19] and Dorfman et al.[20]

Both the groups showed statistically nonsignificant difference in GI. Results may be attributed to oral hygiene instructions rendered to the patients and patient compliance to those. These results also suggest that both 5-0 silk suture and n-butyl-2-cyanoacrylate did not enhance gingival inflammation and are well tolerated by host tissue. Results of the present study are in agreement with the findings of Hangorsky and Bissada[19] and Dorfman et al.[20]

In Group I, statistically significant achievement in mean gingival recession reduction of 2.37 mm and 2.91 mm was reported from baseline to 3 months and baseline to 6 months, respectively. A statistically significant reduction in mean gingival recession of 1.58 mm and 2.04 mm was reported from baseline to 3 months and baseline to 6 months, respectively, in Group II. The results are parallel to the studies conducted by Paknejad et al.,[8] Deeplakshmi and Balu,[21] and Gumus and Buduneli.[11]

There was an increase in recession coverage of 0.54 mm and 0.46 mm from 3 months to 6 months, respectively, in both the groups; the difference was statistically nonsignificant. Similar results had been reported in previous studies by Matter,[22] Hangorsky and Bissada,[19] and Dorfman et al.[20] This finding might be because of creeping attachment. This creeping attachment is a postoperative migration of the gingival marginal tissue in a coronal direction, covering partially or totally a previously denuded root. The gingival tissue becomes firmly attached to the root surface, and the probing does not show any sulcular depth.

A statistically significant gain in CAL of 2.33 mm and 3.00 mm in Group I from baseline to 3 months and from baseline to 6 months, respectively, was reported. Group II had a statistically significant gain in CAL of 2.29 mm and 2.83 mm from baseline to 3 months and from baseline to 6 months, respectively. Similar results were recorded by Barbosa et al.[23] and Gumus and Buduneli.[11] A gain in CAL may suggest new attachment, reattachment, or periodontal regeneration.

There was a statistically significant gain in WK of 1.16 mm and 1.37 mm in Group I from baseline to 3 months and baseline to 6 months, respectively. Group II had a statistically significant gain in WK of 0.83 mm and 0.91 mm from baseline to 3 months and baseline to 6 months, respectively. The results are parallel to the studies conducted by Popova and Boyarova,[24] Anand et al.,[25] and Gumus and Buduneli.[11] In both the groups, a statistically significant gain in WK could be the outcome of recession coverage attained. Intergroup comparison yielded statistically insignificant difference in WK (P > 0.05) from baseline to 3 months and from baseline to 6 months.

In the present study, it was planned to assess the alteration in gingival tissue thickness after gingival recession treatment. Gingival tissue thickness is an important factor that could be relevant in increasing the risk for gingival recession and can affect the outcome of the treatment. A significant increase in the gingival tissue thickness was observed from baseline to end of study period in both the groups. Similar results were observed in the findings of Silva et al.[26] and Aroca et al.[27]

A few advantages of n-butyl-2-cyanoacrylate over silk suture observed during the course of the study were ease of application, less operating time, no adverse reaction during the entire process of graft healing, and better patient compliance. Similar results were observed in the findings of Zenóbio et al.[28] and Gumus and Buduneli.[11]

CONCLUSION

During the course of the study, it was observed that n-butyl-2-cyanoacrylate was easy to apply, consumed less operating time, and had no adverse reaction during the entire process of graft healing. The present study had few limitations which include smaller sample size, shorter follow-up period, and noninclusion of histological evidence.

Despite the limitations of the study, it can be concluded that both 5-0 silk suture and n-butyl-2-cyanoacrylate were equally efficacious in the stabilization of FGG harvested with Er:YAG laser for augmentation of keratinized tissue in the management of Class I and II gingival recession.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.