Year : 2010 | Volume
: 21 | Issue : 2 | Page : 174--178
Evaluation of alteration in mucogingival line location following use of subepithelial connective tissue graft
Fariba Saleh Saber
Department of Prosthodontics, Dental faculty, Golgasht Ave, Tabriz, Iran
Fariba Saleh Saber
Department of Prosthodontics, Dental faculty, Golgasht Ave, Tabriz
Aim and Objective : The aim of this study is to evaluate the positional changes that occur in mucogingival line following the use of subepithelial connective tissue graft (SCTG).
Materials and Methods : In 19 Miller class I or II gingival recession defects, distance between mucogingival line (MGL) and cemento-enamel junction, also width of keratinized and attached gingiva, and clinical attachment level were measured. SCTG were used for covering the exposed roots. A fore mentioned parameters were repeated at 3, 6 and 12 months after surgery and alterations were measured. Paired t test was used to analyze the results.
Results : MGL had been moved in coronal direction (4.39 ± 0.77 mm on average) during surgical approach. After 1 year, MGL shifted 2.11 ± 0.7 mm apically. In accordance with this apical shift, a significant increase in the width of keratinized and attached gingival width (2.89 ± 0.63 mm and 2.82 ± 0.5 mm, respectively) was seen (P < 0.05).
Conclusion : MGL tended to revert back to its original position following the use of SCTG, and this reversion is accompanied with an increase in the keratinized and attached gingival width.
|How to cite this article:|
Saber FS. Evaluation of alteration in mucogingival line location following use of subepithelial connective tissue graft.Indian J Dent Res 2010;21:174-178
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Saber FS. Evaluation of alteration in mucogingival line location following use of subepithelial connective tissue graft. Indian J Dent Res [serial online] 2010 [cited 2021 Apr 17 ];21:174-178
Available from: https://www.ijdr.in/text.asp?2010/21/2/174/66628
Mucogingival line (MGL) is the borderline between the basal bone, which is determined genetically, and the alveolar bone, which forms simultaneously with tooth eruption.  Ainamo and Talari showed that the position of MGL remains stable with age in relation to fixed skeletal landmarks.  In another study, Ainamo et al. performed an apically repositioned flap procedure in the mandibular anterior tooth region and after 18 years showed that the MGL had regained its original position. 
Recent studies on MGL location alteration following coronally advanced flaps have shown that the MGL tends to regain its original position. , It is interesting to note that an increased gingival height is also reported following a coronally positioned flap procedure alone, ,, although some studies have reported a decrease in the width of keratinized gingiva in short term. ,,,
The changes in the position of MGL that occurs following the coronally positioned flap have been studied previously.  However, there is limited data about changes in the position of MGL and dimensional changes in keratinized and attached gingiva following subepithelial connective tissue graft. The purposes of the present study were evaluating the mucogingival line, clinical attachment level and keratinized and attached gingival width changes, at 3, 6 and 12 months following the use of subepithelial connective tissue graft, in Miller class I or II gingival recession defects.
Materials and Methods
Nineteen gingival recession defects in 10 patients aged between 28 and 58 years (mean 38.45 ± 9.23) who had referred to the periodontics section of Tabriz Faculty of Dentistry was included in this study. Informed consent was signed by each subject after thorough explanation of nature, risks and benefits of the clinical investigation and associated procedures. The patients have at least one Miller class I or II gingival recession with minimum height of 4 mm in incisors, canines or premolars. Patients with a history of smoking, alcoholic beverages drinking, full-mouth plaque and bleeding indices  scores >20% and any systemic diseases affecting the periodontal tissues were excluded.
After preparing an alginate impression and a surgical stent by a prosthodontist for reproducibility of measurements, the baseline clinical measurements were taken and rounded to the nearest 0.5 mm by using a UNC (University of North Carolina) periodontal probe. These measurements were carried out by a calibrated periodontist with 10 years of clinical experience. All surgeries were performed by another expert periodontist.
The following clinical parameters were assessed on the buccal aspect of all study teeth at baseline, 3, 6 and 12 months after surgery:
Recession depth (RD): distance between CEJ and gingival marginMucogingival line location (MGL): distance between CEJ and MGL (which was determined through visual method)Keratinized gingiva width (KGW): distance between gingival margin and MGLClinical attachment level (CAL): distance between CEJ and bottom of gingival sulcusClinical probing depth (CPD): distance between gingival margin and bottom of gingival sulcusAttached gingiva width (AGW): calculated by subtracting CPD from the width of keratinized gingiva
After local anesthesia (2% lidocaine with 1:80000 epinephrine) two horizontal incisions (extended 3 mm each in the mesial-distal direction) performed at a distance from the vertex of the anatomic papilla equal to the depth of the recession; and two bevelled vertical-releasing incisions that extended into the alveolar mucosa. A periosteal elevator was used to carefully reflect an initial full-thickness flap. A split-thickness flap was elevated and all muscle insertions were eliminated to facilitate its coronal displacement. The root surface was mechanically treated with the use of curettes. The papillae adjacent to the involved tooth were de-epithelialized.
In order to harvest connective tissue graft a second surgical site was created on the palate. The incisions were placed between the distal aspect of the canine and the midpalatal region of the first molar area with the trap-door technique. A connective tissue graft in an adequate size of 1.5 mm thickness was harvested, and pressure was applied to the donor area with gauze soaked in saline after the graft was taken.
The donor area was closed with silk 4-0 sling sutures. Then the graft was trimmed with a sharp surgical blade and was introduced to the recipient area in such a way that its coronal part would lie on the CEJ of the considered tooth.
Subsequently, the graft was fixed using 5-0 chromic gut suture and the flap was displaced coronally, completely covering the graft, and fixed with a nonresorbable suture and a sling suturing technique [Figure 1]. Finally, interrupted sutures were placed at the vertical incisions to facilitate tissue stabilization. No periodontal dressing was used.
The patients were instructed to rinse with 0.2% chlorhexidine digluconate for 1 minute twice a day for 3 weeks; furthermore, Ibuprofen 400 mg every 6 hours for 2 days for pain relief and amoxicillin 500 mg every 8 hours for one week were prescribed. Sutures were removed after 1 week. Patients were instructed to resume tooth brushing 3 weeks after surgery, using a gentle roll technique with a soft toothbrush. Recall appointments for professional supragingival tooth cleaning were scheduled every week for the first month, 2 months after surgery and every 2 months thereafter.
Data were analyzed using statistical software (SPSS version 13). The significance level established for all analyses was 5% (P<0.05). Clinical parameters at baseline and 3, 6 and 12 months were compared using paired Student t test.
The Kolmogorov-Smirnov test of baseline data showed a homogenous distribution of the data. [Table 1] shows the frequency distribution of recession defects with respect to tooth and jaw type. The values of clinical parameters at the baseline and 3, 6 and 12 months after surgery are reported in [Table 2]. The mean plaque and gingival scores were low throughout the 1-year follow-up period (13% ± 7% and 11% ± 6%, respectively).
The distance between MGL and CEJ immediately after surgery was 1.55 ± 0.58 Millimeter (mm). During the recall periods all the measurements indicated a gradual shift of MGL apically. At 3, 6 and 12-month follow-up periods the mean apical displacement of mucogingival line were 1.58 ± 1.02 mm, 1.79 ± 0.83 mm, and 2.11 ± 0.7 mm, respectively.
The width of the keratinized gingiva was 1.55 ± 0.76 mm at baseline, which increased to 2.78 ± 0.53 mm, 3.07 ± 0.47 mm and 3.44 ± 0.49 mm at 3, 6 and 12 months after surgery, respectively.
The width of the attached gingiva increased from 0.36 ± 0.62 mm at baseline to 1.63 ± 0.54 mm, 2.05 ± 0.52 and 2.18 ± 0.50 at 3, 6 and 12 months, respectively.
Clinical attachment level was 5.81 ± 0.88 mm prior to surgery, that at 3, 6 and 12 months, improved to 1.52 ± 0.65 mm, 1.34 ± 0.44 mm and 1.55 ± 0.57 mm, respectively.
All clinical measurements changed significantly between baseline and three-month period (P<0.05). The attached gingiva also increased significantly between 3 and 6 month follow-up (P<0.05). Differences between 3 and 6 months as well as 6 and 12 months in other clinical parameters were not statistically significant.
The results of this study showed a gradual reversion of MGL apically following the use of subepithelial connective tissue graft. The distance from MGL to CEJ was 5.94 ± 0.88 mm at baseline. MGL moved 4.39 ± 0.65 mm in the coronal direction during the surgery. The apical movement of the mucogingival line was 1.58 ± 1.02 mm at 3 months, 0.21 ± 0.16 mm from 3 to 6 months and 0.31 ± 0.11 mm from 6 to 12 months. The maximum apical displacement of MGL was in the interval between baseline and 3 month, which was significant.
Gurgan et al. studied MGL changes following use of "coronally advanced flap" technique.  The position of MGL was moved coronally to as much as 2.31 ± 0.72 mm during surgery. The results showed that MGL has moved 1.3 mm apically during 60 months and the greatest amount of reversion occurred between baseline and 1 month after surgery (0.3 mm). In Gurgan's study, MGL moved 0.51 mm (21%) apically after a period of 1 year, which is less than the finding of the present study (2.1 mm or 48% of reversion). This difference may be due to a different type of gingival recession defects and the amount of coronal displacement of MGL between the two studies. In Gurgan's study, Miller Class I defects with an average depth of 2.43 ± 0.75 mm were treated, but in the present study, Miller Class I and II with an average depth of 4.39 ± 0.65 mm were included. Furthermore in the present study, connective tissue graft was used under coronally positioned flap that could be considered as another reason for differences in the results.
Wennstrom and Zucchelli used coronally advanced flap with connective tissue graft in 35 Miller Class I gingival recession defects with a minimum depth of 3 mm.  During surgery, MGL was moved 4 mm coronally on average, which was displaced 2.9 mm apically at 2 years (72.5% of reversion), which is greater than the findings of the present study. This difference can be explained by the longer follow-up period of Wennstrom's study.
Zucchelli et al. used coronally advanced flap with connective tissue graft to treat 18 Miller Class I and II gingival recession defects and moved MGL as much as 5.6 mm in coronal direction at surgery.  One year following the surgery, MGL reverted back 3.4 mm on average (60% reversion), which is in agreement with the results of the present study.
Keratinized gingival width was 1.55 ± 0.76 mm at baseline, which increased to 2.87 ± 0.53 mm, 3.07 ± 0.47 mm and 3.44 ± 0.49 mm at 3, 6 and 12 months after surgery respectively. The greatest level of increase occured between baseline and 3 months after surgery (1.23 ± 0.47 mm). Only the changes between baseline and 3 months were significant (P<0.05).
In Gurgan's et al. study, the width of keratinized gingiva was 3.68 ± 1.17 mm at baseline, which reduced to 2.96 ± 1.19 mm within 1 year after treatment, which is in contrast with the results of present study.  This difference may be due to the fact that in Gurgan's study, only the CPF technique was used, while in the present study CPF with connective tissue graft was used, which may have inductive effects on overlying mucosa and cause an increase in KG width. On the other hand, in his study root coverage percentage was much less than the present study (54% versus 94% at 12 months after surgery).
In Wennstrom and Zucchelli's study in which a similar method as the present study was used, the width of KG increased significantly from 0.9 ± 0.5 mm to 3.7 ± 0.6 mm 2 years after-surgery, which is in agreement with the findings of the present study. 
Chambrone and Chambrone used subepithelial connective tissue graft in the treatment of multiple gingival recession defects and reported a significant increase in keratinized gingival width (from 1.66 ± 1.09 mm at baseline to 3.82 ± 0.91 mm 6 months after surgery). 
The healing events in the marginal tissues may be responsible for increasing the width of keratinized gingiva. It has been shown that granulation tissues originating from periodontal ligament could form a connective tissue similar to gingival connective tissue and with the potential to induce keratinization of the covering epithelium. , Also, the tendency of the MGL to regain to its "genetically" defined position could expose underlying connective tissue graft, which would be turned to keratinized tissue.
It can also be attributed to the inductive effect of connective tissue graft, which is harvested from hard palate or may be due to apical movement or recession of the overlying flap.
Furthermore, the findings of this study indicate a significant increase in the width of attached gingiva as much as 1.82 ± 0.78 mm during 1-year follow-up [Figure 2]. The maximum and minimum increases were seen between baseline and 3 months (1.27 mm), and between 6 and 12 months (0.13 mm), respectively. Since the clinical probing depth was stable during the follow-up period, there is a close relation between the increased level of the width of keratinized and attached gingiva, and some researchers believe that the improvement in these two parameters is of great importance, which reduces the risk of recession defects recurrence. ,
Clinical attachment level (CAL) improved 4.29 ± 0.91 mm between baseline and 3 months after surgery and since then it almost remained unchanged. Since the CPD was low and almost remained stable during the follow-up period so there is a close relationship between amount root coverage (94.5%) and the improvement of CAL. Similar results have been reported in other studies. ,,
Finally, the results of this study showed that MGL tends to revert back to its primary position following placement of connective tissue graft with coronally positioned flap, and this reversion is accompanied by an increase in the width of keratinized gingiva. This apical displacement was faster in the first three months after surgery but subsequently it occurs slowly. Nonetheless, in this study MGL had not reverted back to its original position even after 12 months after surgery. Reversion of MGL may complete in longer periods of time. Further long-term studies recommended evaluating this phenomenon.
After the use of SCTG technique, MGL tended to revert back to its original position and this reversion is accompanied with an increase in the keratinized gingival width.
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