Minimally Invasive Coronally Advanced Tunnel

A Novel Surgical Technique for Treatment of Multiple Recession Defects: A Case Series

Joann Pauline George, M.D.S.; Divya Khanna, B.D.S., M.D.S.

ABSTRACT

Perio-plastic surgeries are a continuously evolving and expanding field of research. A multitude of options are available for root coverage. Connective tissue grafts are the gold standard but have limitations, including patient morbidity, invasiveness and scar formation.

The aim of this study is to evaluate the effectiveness of a novel minimally invasive coronally advanced tunnel (MI-CAT) technique for treatment of multiple recession-type defects (MRTD). The technique involves a muco-periosteal tunnel and stabilization of the advanced gingival margin by using orthodontic buttons as anchor units for two weeks postsurgery.

After six months, enhanced root coverage (92.28%), excellent esthetics and significant improvement in periodontal parameters were achieved. The results indicate that the MI-CAT technique proved to be effective, minimally invasive and a predictable option for treatment of MRTD.

Gingival recession is a frequent finding, with an average 1 mm of recession in approximately 80% of the adult population. [1] The term denotes the oral exposure of root surfaces due to displacement of the gingival margin apical to the cementoenamel junction. [2] The condition results in unfavorable esthetics, a roller-coaster of soft- and hard-tissue anatomy, gingival clefts and fissures, loss of keratinized attached gingiva, increased root caries susceptibility and dentin hypersensitivity. [3,4]

Trauma from toothbrushing, malposition of teeth, periodontal disease, and ectopic insertion of freni and muscle attachment are the main etiological factors for Miller Class I and Class II recession defects. [5] Increasing age, periodontal disease and smoking are environmental factors that negatively influence gingival health, and recession is frequently seen in these individuals. [1] The affliction of multiple adjacent teeth with recession have been termed Multiple Adjacent Recession Type Defects (MARTD) [6] or Multiple Recession Type Defects (MRTD) interchangeably in scientific literature. [5]

Currently there are a multitude of perio-plastic surgical techniques for soft-tissue coverage of the exposed root surfaces in MRTDs. These include the coronally advanced flap (CAF), the modified CAF, [7] modified CAF with an subepithelial connective tissue graft (CAF+SCTG), [8,9] CAF with connective tissue graft (CAF+CTG), [9,10] CAF with orthodontic buttons, [6] expanded mesh technique, [11] vestibular incision subperiosteal tunnel access technique (VISTA), [12] CAF with and without vertically releasing incisions [13] and the pinhole surgical technique. [14] This is a continuously evolving and expanding field of research, and these surgical techniques have achieved complete root coverage (CRC) in 35% to 90% of recession defects. [5,9]

Among the various factors that influence the treatment outcome, the final position of the gingival margin (GM) [15] plays a critical role in achieving CRC. [16] Surgical anatomy and technique-related factors, such as flap thickness, [16] flap tension before suturing, [17] GM location at the end of surgery and the passivity with which it is displaced coronal to CEJ seem to dictate to a large extent the probability of achieving CRC. [18] The greater postoperative advancement of the GM under minimal tension favors a desirable outcome. [15,16]

Chao, in 2012, [14] reported a pinhole surgical technique (PST) that employed a vestibular incision to elevate a sub-periosteal tunnel that was freely movable, coronally displaced and stabilized with either a malleable bio-resorbable membrane or a collagen matrix. The surgical follow-up at 18 months showed a positive outcome. However, the lack of suturing and connective tissue barrier at the recession site may negatively influence the long-term stability of the results achieved, as noted by Marggraf et.al. [23]

Prevention of tissue collapse after the surgical procedure can better stabilize the flap during the critical two weeks of initial wound healing. This can be achieved by composite stops at the contact point [19] and orthodontic buttons. [6] Therefore, we propose a mimimally invasive coronally advanced tunnel technique (MICAT) that is a modification of the PST, wherein the freely movable tunnel is coronally advanced and sutured. This suturing technique was combined with orthodontic buttons to prevent the collapse of the suspended sutures. In the case series presented here for the first time, we have discussed the clinical outcome of this modification for enhanced root coverage and aesthetic results.

Materials and Methods A total of 35 recession defects were selected in seven patients in the age group 25 to 55 years, with a mean age (46.12 ± 9.40 years). Subject inclusion criteria were as follows: 1) Multiple (at least two or three) Millers Class I and II or combined Class I and II recession defects [14] affecting adjacent teeth of the maxillary arch; 2) Patients with thick gingival biotypes >0.8mm;16 3) Presence of adequate keratinized tissue apical to recession > 1mm; [5] 4) Systemically healthy (American Society of Anesthesiologists Physical Status I or II) [14,20] ; 5) No contra-indications for periodontal surgery; [14] 6) Nonsmokers; [5,21] 7) Patients with esthetic concerns; [22] 8) Patients with history of compliance to oral hygiene instructions and a full-mouth plaque score of <10% (O Leary 1972).

Patients with the following criteria were excluded from the study: 1) Recession defects associated with caries/demineralization and deep abrasions (step >2mm); [6] 2) occlusal interferences; [6] 3) Teeth with evidence of pulpal pathology; [6] 4) Patients who have undergone previous periodontal surgical procedures at the involved sites; [14] 5) Pregnant and lactating women; 6) Patients on medications known to interfere with periodontal tissue health or healing. [13]

Detailed, thorough medical and dental histories were obtained, and each patient was subjected to comprehensive clinical and radiological examination. All patients were informed about the nature of the study, surgical procedure involved, potential benefits and risks associated with the surgical procedure; and a written informed consent was obtained from all patients.

The study was strictly conducted in accordance with the principles of World Medical Association, Declaration of Helsinki (version 2008), and the study protocol was reviewed and approved by the Institutional Ethical Committee and Review Board (REF:KCDS/168a/2013-2014) of Krishnadevaraya College of Dental Sciences and Hospital, Banglore, India, affiliated with Rajiv Gandhi University of Health Sciences (RGUHS).

The primary objective of this study was to evaluate the effectiveness and predictability of the MI-CAT surgical technique in the treatment of multiple adjacent recession defects. The secondary objective of the study was to assess the influence of these surgical procedures on the gingival and periodontal health.

The primary clinical outcomes assessed were: the difference in gingival recession depth (GRD); complete root coverage (CRC); root coverage esthetic score (RES); location of the gingival margin achieved immediately postsurgery; and gingival recession width (GRW). The secondary outcomes that were assessed were: difference in probing pocket depth (PD); clinical attachment level (CAL); and width of keratinized tissue (KTW).

Case Series

All patients received scaling and thorough root planing and oral hygiene instructions. A coronally directed roll technique for brushing was prescribed. Surgical treatment of the recession defects was scheduled after the patient demonstrated an adequate standard of supragingival plaque control (plaque score <10% O Leary 1972). Clinical parameters were recorded to the nearest millimeter using a UNC-15-probe (University of North Carolina -15periodontal probe – Hu Friedy, Chicago, IL) at baseline, six weeks, three months and six months.

Prior to starting the surgery, orthodontic buttons (PrimeOrthodontics, Inc., Portland, OR) were bonded to the middle of the middle one-third of the crown of the tooth with dental cement.* (Figure 1A) to prevent the future collapse of the suspensory sutures. A modification of the original PST, [14] however, with a different elevator was carried out. Under local anaesthesia, 2% lignocaine hydrochloride, † using a No. 15 scalpel (Bard Parker), a minimum horizontal incision of 2 mm to 3 mm was made in the alveolar mucosa near the base of vestibule, apical to recipient sites. Papilla elevator ‡ was inserted through the entry incision and sulcular incision, and a full thickness mucoperiosteal flap was elevated and extended coronally and horizontally to allow for elevation of two adjacent papillae on each side of denuded roots (Figure 1B). The mucoperiosteal flap elevation was extended beyond the MGJ in the surgical area and under each papilla. Muscle and collagen fibers under the mucoperiosteal flap were dissected in order to facilitate a passive coronal positioning of the flap and papilla (Figure 1D). The interproximal extension of flap resulted in a freely movable flap, which was then positioned coronally to extend beyond cementoenamel junction (CEJ).

Figure 1. (A) Application of orthodontic buttons. (B) Intraoperative view of minimally invasive incision and elevation of muco-periostealtunnel with TKN2 instrument. (C) Tucking of bioresorbable membrane intominimially invasive tunnel. (D) Passive coronal advancement of tunnelachieved. (E) Modified sling suturing technique using orthodonticbuttons as anchor units for coronally advanced tunnel. (F) Suturingcompleted with interdental sutures along with modified sling sutures.

Figure 2. Digimizer evaluation of: (A) Location of gingival margin before MI-CAT surgery; (B) Coronal advancement of gingival margin achieved by 1.715 ± 0.830 mm (p< 0.001) beyond CEJ immediately after MI-CAT surgery.

A malleable bioresorbable collagen membrane § was then tucked with curved tissue forceps under the CAT (Figure 1C). Sling sutures with 5-0 (non-absorbable surgical sutures)** were used to suspend the central area of the flaps on the buttons. The second sutures, with 6-0 (non-absorbable surgical sutures), were performed to accomplish a precise adaptation of the buccal flap on the convexity of the underlying crown surface and permitted the stabilization of every

At the end of surgery, the flap margins were at least 2 mm coronal to achieved by 1.715 ± 0.830 mm (p< 0.001) beyond CEJ immediately after MI-CAT surgery.

CEJ of all teeth (Figure 2). Gentle digital pressure was applied for approximately five minutes. [14] Periodontal dressing† † was applied to avoid any mechanical trauma. [6]

Postoperative instructions recommended a 0.12% chlorhexidine gluconate mouthrinse and avoidance of brushing at surgical site for six weeks. Tab ibuprofen 400 mg thrice daily for three days and cap amoxicillin 500 mg thrice daily for seven days were prescribed.

The sutures, orthodontic buttons and periodontal dressing were removed 14 days after surgery. Clinical parameters were recorded at six weeks, three months and six months after surgical reconstruction.

* Dual Cure Glass Ionomer Cement 3M ESPE, USA.

† Lignox 2%, Indoco Remedies Ltd, Goa, India.

‡ TKN2, Hu Friedy, Chicago, IL, USA.

§ HealiguideTM, EnColl Corp. USA.

** Mersilk, Ethicon, Johnson & Johnson, Himachal Pradesh, India.

† † Coe Pack—Non-Eugenol Periodontal Dressing, GC America Inc. ALSIP, IL, USA.

Figure 3. Two different cases showing: (A) Preoperative view of recession defect; (B) Recession coverage achieved by MI-CAT surgery withstable results after six-month follow-up.

Figure 4. Third case. (A) Preoperative view of recession defect. (B) Recession coverage achieved by MI-CAT surgery with stable results aftersix-month follow-up.

Statistical Analysis

A software package SPSS‡ ‡ was used for statistical analysis. All parameters were assessed at baseline, six weeks, three months and six months by ANOVA. Pairwise comparison between different visits (baseline to six months) was performed using Tukey post-hoc analysis and Wilcoxon signed-rank test. Student “t” test was done to evaluate advancement of gingival margin achieved postoperatively. Difference associated with p value < 0.05 was considered statistically significant. Results were presented as mean ± SD.

‡ ‡ IBM SPSS Statistics 21.0; SPSS, Chicago, IL, USA.

Results

A total of seven patients with 35 multiple adjacent recession-type defects (MARTD) were included in the study. All patients included in the clinical trial completed the study. No patient reported any postoperative complications or adverse effects, such as severe edema, pain or sensitivity. Healing was noted to be uneventful in all cases. The results are summarized in Tables 1-3.

A statistically significant (p< 0.001) reduction in the gingival recession depth was noted from baseline to three months, after which the results were stable up to six months follow-up (Table 1). Similarly, the gingival recession width also showed a statistically significant reduction at six months (Table 1).

The mean root coverage (MRC) achieved at six weeks follow-up was 87.42%; at three months it was 92.28%; and it remained the same, 92.28%, at six months follow-up. Out of the 35 teeth treated with MICAT, 29 teeth, 82.9%, showed complete root coverage (CRC) at six months follow-up postsurgery (Figures 3, 4; Table 3).

Even though there was a minimal gain in the keratinized tissue noted from baseline to six months, it was not statistically significant (p= 0.930). The root coverage esthetic score was 9.83/10, which was highly satisfactory (Figures 3, 4; Table 3).

There was a statistically significant (p< 0.001) difference achieved in probing depth from baseline: 1.66 mm to 1 mm at six months. The clinical attachment gain of 2.60 ± 0.617 was noted from baseline to six months, which was statistically significant p< 0.001 (Table 1).

There was a statistically significant (p< 0.001) improvement noted in all periodontal health indices (Table 1).

Discussion

Coronally advanced flap techniques alone and with various modifications have been used widely and successfully for the treatment of MRTD. But these techniques have certain limitations, such as technique sensitivity, invasivity, long procedural time and high morbidity due to a second surgical site. These limitations have led to the need for a newer minimally invasive, practical, short-duration, single-site surgery and patient-centeed approach to the management of MRTD. Flap anchorage with sutures has always resulted in better outcomes [23-26] than techniques without sutures. [27]

Ozcelik et al., in 2011, reported treating 155 recession defects, in which test sites were treated with CAF and button application for stabilization of sutures and coronal stabilization of advanced flap [6] and achieved RC of 96.2% and 66% CRC. Aroca et al., in 2010, reported a new technique that included composite stops placed at the contact points of teeth to prevent collapse of suspended sutures into interproximal spaces, with MRC of 82% and CRC 38%. [28] The placement of orthodontic buttons in the current study helped stabilize the sutures.

In the current trial, GM advancement of 1.71±0.83mm was observed, which is statistically significant (Table 4) with a MRC of 92.28% and CRC of 82.9%. This was similar to the GM postoperative advancement achieved by Ozcelik et al., in 2011 of 1.7±1.3mm, who reported MRC of 96.2%. The rate of CRC outcomes of the present trial was in concordance with the results previously reported in root coverage of MRTDs by CAF+ buttons, VISTA, Zabaleugi et al. 1999, Ribero et al. 2008 and PST. [6,12,14,29,30]

There was a 0.25 mm gain in the KTW, which is similar to that reported by Aroca et al. in 2010. [28] The gain in KTW was insignificant and may be attributed to altered blood supply (Baldi et al. 1999, Pini Prato et al. 2000). [16,17] Also, gain in KTW is a slow phenomenon due to the tendency of the MGJ to regain its genetically determined position. [13,31] A longer follow-up of more than 12 months might have shown more conclusive outcomes. A significant decrease in PPD (2.45mm) was noted as well. The increase in the connective tissue biotype and KTW, which can provide long-term stability, needs to be assessed over a longer time period, and six-month follow-up is insufficient.

The Root Coverage Esthetic Score (RES) was proposed by Cairo et al. in 2009 to evaluate the esthetic outcome following root coverage surgeries, and has been used widely. [32] In the present clinical trial, RES was very high, which denotes a good esthetic outcome achieved at the six-month follow-up (9.83/10).

This surgical technique is minimally invasive, effective and encourages patient compliance. The lack of a second surgical site and vertical releasing incisions leads to a highly predictable esthetic outcome and patient cooperation. Although CAF+ CTG is the gold standard for recession coverage, it may not always be a feasible option, due to the inability to harvest large amounts of CTG for MRTDs in such situations. The proposed surgical technique can cover 8 to 10 recession defects by a minimally invasive approach, where two or three horizontal slit incisions (2-3 mm each incision) for access in the alveolar mucosa is made, and use of collagen membrane will eliminate need for a second surgical site.

Chao had reported the use of specially designed papilla elevators in the PST technique, but in our clinical observation, the TKN2 papilla elevator was effective in raising the coronally advanced tunnel. The use of suspended sutures around the orthodontic buttons provided good coronal stabilization of the flap during the first two weeks of the crucial wound healing period.

The lack of vertical releasing incisions and papilla dissection will lead to a better healing and culminate in better esthetic outcome. The apical vestibular incision was quite effective in aiding flap elevation with the help of tunnelling instruments in areas where recession was deep (>5 mm). This additional incision prevents damage to the GM during sulcular access for tunnelling. The incision was miminal (2 mm) and heals by primary intention uneventfully.

Limitations

The current study reports only seven cases with mean 2.3 mm recession, which is less than ideal for interpretation of quantitative data. The short-term follow-up of six months is another limitation of this study.

Conclusion

Within the limitations of the present study, MI-CAT proved to be an effective, minimally invasive and predictable surgical option for treatment of MRTD in the esthetically compromised maxillary anterior region.

Such advanced, newer, minimally invasive perio-plastic surgical techniques are here to stay. However, more controlled clinical trials reporting the effectiveness and stability of this procedure and its comparison with a control group, that is, the original PST, and with other known techniques of recession coverage in MRTD is needed. Recession defects of >3 mm depth with longer follow-up (>12 months to 5 years) should be considered for future trials. p

The authors report no potential conflict of interest relevant to this article nor source of support. Queries about this article can be sent to Dr. Khanna at drdivyakhanna31@gmail.com.

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Dr. George

Joann Pauline George, M.D.S., is professor, Department of Periodontology, Krishnadevaraya College of Dental Sciences & Hospital, Bangalore, Karnataka, India.

Dr. Khanna

Divya Khanna, B.D.S., M.D.S., is a member of the Department of Periodontology, Krishnadevaraya College of Dental Sciences & Hospital, Bangalore, Karnataka, India.