Sub-epithelial connective tissue graft for root coverage in nonsmokers and smokers: A pilot comparative clinical study.

BACKGROUND: Gingival recession is a common condition and is more prevalent in smokers. It is widely believed that root coverage procedures in smokers result in less desirable outcome compared to nonsmokers', and there are few controlled studies in literature to support this finding. Therefore, the purpose of this study was to evaluate and compare the outcome of root coverage with sub-epithelial connective tissue graft (SCTG) in nonsmokers and smokers.
MATERIALS AND METHODS: A sample of twenty subjects, 10 nonsmokers and 10 smokers were selected each with at least 1 Miller's Class I or II recession on a single rooted tooth. Clinical measurements of probing depth, clinical attachment level (CAL), gingival recession total surface area (GRTSA), depth of recession (RD), width of recession (RW), and width of keratinized tissue were determined at baseline, 3, and 6 months after surgery.
RESULTS: The treatment of gingival recession with SCTG and coronally advanced flap showed a decrease in the GRTSA, RD, RW, and an increase in CAL and width of keratinized gingiva in both the groups. However, the intergroup comparison of the clinical parameters showed no statistical significance. About 6 out of 10 nonsmokers (60%) and 3 smokers (30%) showed complete root coverage. The mean percentage of root coverage of 71.2% in nonsmokers and 38% in smokers was observed.
CONCLUSION: The results of the present study suggest that smoking may negatively influence gingival recession reduction and CAL gain. In addition, smokers may exhibit fewer chances of complete root coverage. Overall, nonsmokers showed better improvements in all the parameters compared to smokers at the end of 6 months.

INTRODUCTION

Periodontal therapy has historically been directed primarily at the elimination of disease and the maintenance of a functional, healthy dentition and supporting tissues.[1] Accordingly, the World Workshop in Periodontics 1989 has recommended the goals of periodontal therapy as immediate, ideal, pragmatic, and ultimate, mainly considering the disease status and patient's ability to maintain oral hygiene and comply with the periodontist's instructions.[2] While these goals still remain important and cogent, an acceptable esthetic outcome has been added as part of periodontal therapy in the last two decades. Patients are increasingly becoming conscious of a pleasing gingival display in addition to tooth form and color. Probably, one of the most common esthetic concerns associated with the periodontal tissues is gingival recession. Esthetics, progression of recession, hypersensitivity, or difficulties with oral hygiene may warrant the need to cover exposed roots.[1]

Among the numerous periodontal plastic surgery approaches documented in the literature for the treatment of gingival recession, sub-epithelial connective tissue graft (SCTG) combined with coronally advanced flap (CAF) is considered as the most predictable technique.[3]

Determinants of a successful root coverage procedure include operative technique, defect characteristics, and patient attributes.[4]

Among the patient related factors, cigarette smoking is known to negatively influence the healing outcome following periodontal surgical procedures including grafting for root coverage. Although the potential negative impact of smoking on the outcome of root coverage procedures was recognized by Miller[5] almost 20 years ago, there are few studies specifically designed to address the role of smoking in periodontal plastic surgery outcomes and the resulting evidence is conflicting.[6]

Gingival recession is a common finding in smokers and since smokers have the same esthetic needs as nonsmokers, the present study was therefore designed to evaluate the outcome of SCTG combined with CAF for root coverage of Miller Class I and II recession defects in nonsmokers and smokers.

MATERIALS AND METHODS

Patient selection

A sample of twenty subjects, ten nonsmokers who acted as control group and ten smokers who formed the test group were selected from patients attending Department of Periodontics and Implantology. The Institutional Ethical Committee has approved the study (VDC-RP/2011-21). All patients completed an informed consent document explaining all procedures involved in the protocol and the possible benefits associated with the proposed study.

Inclusion criteria included the presence of at least one Miller's Class I or II recession in a single rooted tooth; smokers were the subjects smoking on an average of ≥ 5 cigarettes/day for a minimum of 1 year but not smoked during the surgical phase of treatment; nonsmokers consisted of subjects who never smoked or who had quit smoking at least 5 years ago.

The following exclusion criteria were applied for both the groups: Patients with the history of potential medical conditions and those diagnosed with the same during routine investigations, teeth with active periodontitis, i.e., gingival bleeding and acute lesions such as an abscess, root surface restoration at the recession site, Class V carious lesions, teeth with excessive root prominence, teeth placed out of alignment, and thin palatal mucosa.

In a specially prepared proforma, patient's detailed case history was recorded which included among the other items such ashistory of smoking and the following clinical parameters – Plaque index (Silness J and Loe H, 1964), gingival index (Loe H and Silness J, 1963), probing depth (PD), clinical attachment level (CAL), gingival recession total surface area (GRTSA), depth of recession (RD), width of recession (RW), and width of keratinized gingiva (WKG) was determined.

All assessments were carried out with University of North Carolina-15 periodontal probe and the measurements were recorded at baseline, 3, and 6 months after surgery.

All the subjects received initial treatment which consisted of scaling and root planing and oral hygiene instructions. The full mouth periodontal condition was ensured to be normal at least 1 week before the planned surgery. The recessions were treated surgically with a SCTG combined with a CAF using a standard surgical technique. The graft was obtained from palatal region of each patient. Smokers were placed under smoking cessation sessions and were advised to give up smoking completely or at least for 2 weeks from the day of surgery as smoking during this critical phase of treatment would undoubtedly result in failure of the same. Patients who did not comply with the smoking cessation were excluded from the study.

Surgical procedure

The surgical procedure was performed by a single operator for all the cases under local infiltration with 2% lignocaine containing adrenaline at a concentration of 1:200,000 at the recipient site. The local anesthetic solution was slowly injected at the recipient site to avoid any bulla formation. The donor palatal site was anesthetized by a greater palatine nerve block.

At the recipient site, a full thickness flap was elevated till the tooth root was exposed and then a partial thickness flap was elevated beyond the mucogingival junction [Figure 1]. At the base of flap, a cut back incision in periosteum was given so that the flap can be passively positioned coronally over the defect without tension [Figure 2]. The exposed root surfaces were thoroughly planed with curettes. Sterile aluminum foil was used to create a “template” that precisely fits the recipient bed.

Figure 1

Horizontal incisions placed at cemento-enamel junction, followed by crevicular incision. Vertical incisions extend upto mucogingival junction

Figure 2

Full thickness flap elevated till the tooth root was exposed and then partial thickness flap elevated beyond mucogingival junction

The trap door technique proposed by Langer and Langer[7] was used to harvest graft from palate [Figure 3]. The underlying connective tissue graft of adequate thickness (2 mm) and without epithelial collar was harvested [Figure 4]. The palatal flap was repositioned, and the donor site was compressed with wet gauze to eliminate dead space and control bleeding. The palatal flap was sutured with 3-0 silk suture [Figure 5].

Figure 3

Partial thickness flap elevated at donor site

Figure 4

Harvested connective tissue graft

Figure 5

Donor site sutured

The harvested graft was trimmed with a surgical blade, if necessary, and was introduced to the recipient area. The connective tissue graft was positioned with stabilizing sutures using a 4-0 Vicryl (Ethicon™) suture at the level of cemento-enamel junction [Figure 6]. The overlying partial thickness flap was advanced coronally covering the graft and sutured to respective lingual papillae with 4-0 Vicryl (Ethicon™) suture. The vertical incisions were then sutured with two direct interrupted sutures on either side [Figure 7]. The surgical site was covered with tin foil of suitable size, and a noneugenol periodontal dressing (Coe-Pak™) was placed.

Figure 6

Connective tissue graft placed at the recipient site at level of cemento-enamel junction, sutured and stabilized with 4-0 vicryl (Ethicon™)

Figure 7

Flap advanced coronally and stabilized by interrupted sutures using 4-0 vicryl (Ethicon™)

Postoperative care

All the subjects received postoperative antibiotics (amoxicillin 500 mg thrice daily for 5 days) and analgesics (combination of ibuprofen 400 mg, paracetamol 325 mg thrice daily for 3 days). Routine postoperative instructions were given. The patients were refrained from toothbrushing at the surgical site for 4 weeks and were instructed to rinse mouth with 0.2% chlorhexidine gluconate mouthwash daily for 6 weeks. They were asked to report immediately if periodontal dressing got displaced in <2 weeks or if they experienced any untoward bleeding from surgical area (donor and recipient).

In 2 weeks postoperative checkup, the periodontal dressing was removed and saline irrigation was done at surgical site. The sutures in donor site were removed.

From the 4th week of surgery, the patients were asked to start gentle brushing using a soft toothbrush in the operated area. The subjects were recalled monthly for 6 months postoperatively to reinforce oral hygiene instructions and plaque control.

Statistical analysis

Descriptive statistics was expressed as mean ± standard deviation. Statistical analysis of data was comparative and nonparametric. The Mann–Whitney U-test was used to determine the possible intergroup differences 3 and 6 months postoperatively. The Wilcoxon signed-rank test was used to analyze if the principle variables, i.e., GRTSA, RD, RW, and WKG were different between intervals of time (intragroup differences: Baseline–3 months, baseline–6 months, and 3–6 months). A level of significance of 5% was assumed (P < 0.05). Normality test using Shapiro–Wilk test was done.

RESULTS

All the patients completed the study, there being no dropouts. In none of the patients, any postoperative complications such as excessive pain, postsurgical bleeding from grafted or recipient site, necrosis of tissues was observed. Moreover, no sloughing of graft was seen. Patients were recalled regularly once in a month throughout the study period in order to reinforce oral hygiene. All measurements were made at baseline, 3rd, and 6th month.

The age of participants ranged between 19 and 58 years with the mean age 27.6 years for nonsmokers (27.6 ± 10.32) and 38.3 years for smokers (38.3 ± 12.03). There were 6 females and 4 males in nonsmoker group, whereas all the participants in smoker group were males.

Smoking history

The average number of cigarettes the subjects smoked ranged from at least 5 cigarettes/day to maximum of 20 cigarettes/day. All the subjects in test group were light to moderate smokers, 7 being light smokers (5–10 cigarettes/day), and 3 were moderate smokers (10–20 cigarettes/day). None of the patients were heavy smokers (>20 cigarettes/day). The number of years the patients smoked ranged from a minimum of 1 year to a maximum of 30 years. The mean pack years calculated was 3.27 years. Except for one patient who had a smoker's palate, none of the other smokers showed any oral lesions attributable to smoking.

Periodontal variables

The plaque score for nonsmokers was 0.42 ± 0.15 and 0.63 ± 0.28 for smokers and gingival score of nonsmokers was 0.36 ± 0.18 at baseline and 0.39 ± 0.19 for smokers at 3 months. Due to constant reinforcement of oral hygiene, the plaque score decreased to 0.39 ± 0.14 and 0.56 ± 0.27 in nonsmokers and smokers, respectively, and the gingival score of nonsmokers decreased to 0.27 ± 0.94 and to 0.33 ± 0.13 in nonsmokers at the end of 6 months. These differences in plaque and gingival score was not statistically significant between nonsmokers and smokers.

The percent of change in position of gingival margin from immediate postoperative period to 6 months are significant within groups. However, between the groups, there is no significant change.

The mean PD of concerned tooth at baseline was 1.41 ± 0.44 mm in controls and 2.18 ± 0.65 mm in test group [Table 1]. This did not change significantly throughout the study period. However, smokers had deeper PD which was statistically significant. The mean CAL in nonsmokers improved 3 months and 6 months. This gain in CAL was statistically significant from baseline to 3 months and also up to 6 months (P < 0.05). However, there was no difference in readings between 3rd and 6th month. In smokers, gain in CAL was statistically significant from baseline to 6 months (P < 0.05) but no difference was seen from 3 to 6 months [Table 2]. However, when compared within the two groups, the gain in CAL was higher in nonsmokers and the difference being statistically significant.

Table 1

Comparison of probing depth scores between smokers and nonsmokers at different time intervals

Table 2

Comparison of clinical attachment level scores between smokers and nonsmokers at different time intervals

Significant root coverage was observed in both nonsmokers [Figure 8a–c] and smokers [Figure 9a–c] in this study. About 6 out of 10 nonsmokers (60%) and 3 smokers (30%) showed total root coverage. The mean percentage of root coverage in nonsmokers was 71.2% and 38% in smokers. At the end of 6 months, the mean GRTSA [Table 3] reduced from 4.10 ± 1.96 mm2 to 1.18 ± 1.96 mm2 with a mean gain of 2.93 mm in nonsmokers and the mean GRTSA reduced from 4.20 ± 3.64 mm to 2.60 ± 3.03 mm with a mean gain of 1.60 mm in smokers. The mean RD [Table 4] and mean RW reduced with a mean gain of 1.5 mm and 1.85 mm, respectively, in smokers [Table 5].

Figure 8

(a) Miller's Class I recession in relation to 41; (b) 3 months postoperative view; (c) 6 months postoperative view

Figure 9

(a) Miller's Class I recession in relation to 23; (b) 3 months postoperative view; (c) 3 months postoperative view

Table 3

Comparative evaluation of mean gingival recession total surface area scores between the groups at different time intervals

Table 4

Comparative evaluation of mean recession depth scores between the groups at different time intervals

Table 5

Comparative evaluation of mean recession width scores between the groups at different time intervals

There was no statistically significant difference between the groups in increase in WKG from baseline to 3 months and baseline to 6 months but a statistical difference was seen from 3 to 6 months (P < 0.05) [Table 6].

Table 6

Comparative evaluation of mean width of keratinized gingival between the groups at different time intervals

DISCUSSION

The ultimate goal of a root coverage procedure is the complete coverage of the recession defect and an optimal integration of the covering tissue with the adjacent soft tissue. Complete root coverage enhances esthetics and reduces root sensitivity. Additional benefits that result from treating exposed roots include an increase in the width and thickness of the gingiva and prevention of progression of recession in areas where oral hygiene cannot be adequately maintained. Several surgical procedures have been employed over the years to achieve these goals with varying outcomes.

The success of root coverage is determined by various factors including patient-related, site-related, technique-related factors, and operator experience.[8] One of the major patient-related factors that is known to interfere in the successful outcome has been smoking. In this study except smoking, all the other determinants were controlled in both the groups. A healthy periodontium, optimal oral hygiene, similar grades of gingival recession were seen in both groups. All the patients were in good systemic health. Their brushing techniques were supervised and controlled, and it was ensured that no other confounding factors such as trauma from occlusion, malpositioned teeth, and root prominence interfered with the outcomes.

The bilaminar technique followed in this study viz., CAF and SCTG has demonstrated a high percentage of root coverage with excellent color match and without significant postsurgical complications in many of the previous studies.[910] Hence, it can be categorically assumed that other than smoking, the two groups were similarly matched in all aspects.

The results of this study demonstrated improvements in all the parameters in both nonsmokers and smokers. The gingival and plaque index remained at acceptable level in both the groups. Whereas the PD of the patients in both the groups was steady throughout the study period, there was gain in CAL of 0.98 ± 0.67 mm in nonsmokers and 0.64 ± 0.52 mm in smokers. The better CAL gain in nonsmokers albeit small was nevertheless statistically significant. This is in tandem with the findings of previous studies.[1112]

The mean GRTSA reduced in both the groups. However, there was a greater root surface coverage (1.5 mm) in the control group, i.e., nonsmokers compared to the smokers. This is in accordance with the precious study thus showing a negative impact of smoking on the healing outcome though not completely jeopardizing the result.[11]

The mean RD decreased from 2.00 ± 0.41 mm to 0.50 ± 0.75 mm in controls with a mean gain of 1.50 mm and in test group, the mean RD decreased from 2.10 ± 0.81 mm to 1.10 ± 0.99 mm with a mean gain of 1.00 mm at the end of 6 months. In nonsmokers, the mean RW reduced from 3.25 ± 0.92 mm to 1.40 ± 1.90 mm with a mean gain of 1.85 mm and in smokers, the mean RW reduced from 3.70 ± 0.95 mm to 2.40 ± 1.96 mm with a mean gain of 1.30 mm at end of 6 months. Even though upon superficial perusal of these results show better root coverage in nonsmokers; however, there is no statistical significance. Similar contrasting results have been previously reported.[1314]

Two factors standout upon the analysis of the results in both the groups. The periodontal biotype was not taken into consideration in this study. It is known that a thicker biotype provides a better outcome than thinner ones. The second factor is the relative inexperience of the operator.

One difference between the present study and previously reported studies was that all the subjects in smokers group were light to moderate smokers. Most of the adverse results reported in the previous studies[5111516] were seen in heavy smokers (>20 cigarettes/day).

Hence, it can be concluded that smoking although a serious risk factor in poor outcome of the surgical procedures in mouth, better results can be expected in light smokers.

The precise mechanisms by which tobacco smoke interferes with healing are not completely understood, mainly due to the fact that there are thousands of toxins in tobacco smoke and most have not been evaluated for their effect on periodontal healing.[11] Smoking can negatively impact the gingival blood supply by causing vasoconstriction.[17] Nicotine decreases human gingival fibroblast (HGF) proliferation and collagen production by increasing HGF collagenase activity[18] and inhibiting HGF migration.[19] Nicotine is present on the surface of brushed teeth of smokers,[20] and it alters the nature of human fibroblast attachment to root surfaces.[21] Besides nicotine, volatile fractions of cigarette smoke are cytotoxic for HGF.[22] This altered function of fibroblasts due to nicotine exposure could also be the cause of the poor periodontal wound healing seen in cigarette smokers.[23]

Notwithstanding the somewhat variable results seen in this study, and within the limitations of the present study, i.e. small sample size, it can still be opined that smoking is a serious determinant in the poor outcome of root coverage procedures and smokers should be encouraged to quit the habit to ensure successful outcome of all operative procedures in the oral cavity.

Regardless of smoking, the importance of other determinants of successful outcome following root coverage procedures such as meticulous surgical technique, careful tissue handling, and optimal postsurgical care cannot be overemphasized.

CONCLUSION

The bilaminar technique of employing SCTG and CAF in Miller's Class I and II gingival recessions was found to be a predictable procedure and resulted in an acceptable outcome in terms of root coverage, increase in WKG and color match. While nonsmokers demonstrated a mean 71.2% of root coverage, the same was found to be 38% in smokers. Nonsmokers showed superior outcomes in all parameters viz., gain in CAL, RD, RW, WKG compared to smokers.

Thus, within the limitations of the present study, it can be concluded that root coverage with SCTG and CAF may to some extent be negatively affected by smoking and jeopardize the treatment outcome.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.