Modified Tunnel Technique and Double-Layer Acellular Dermal Matrix to Treat Multiple Teeth and Implant: 3.5-Year Results

Gingival recession has been defined as the apical shift of the gingival margin with respect to the ce-mentoenamel junction (CEJ).1 A thin periodon-tal biotype, absence of attached gingiva, and thin alveolar bone are considered risk factors for the development of gingival recession.2 Recession defects can also affect dental implant sites. Mucosal recession has been associ-ated with malpositioned implants and implants with buccal bone defects.3 Thin soft tissue may also lead to increased marginal bone loss around implant sites.4

Numerous techniques have been used to treat recession defects affecting teeth and implants.5 Tunnel techniques utilizing subepi-thelial connective tissue grafts (SCTGs) and acellular dermal ma-trices (ADMs) have been used to protect interdental papillae and promote esthetic results when treating gingival recession sites.6,7 A double layer of ADMs combined with tunnel techniques have been employed to treat multiple adjacent recession defects affecting teeth in the esthetic zone.8 The combination of a lateral pouch and a SCTG has been used to treat recession affecting multiple implants in the esthetic zone.9 Given the success shown in these reports, utilizing these techniques to treat recession defects affecting both implant and tooth sites seems logical. This case report describes the treatment of an implant and multiple teeth using a modified tunnel technique and a double-layer ADM.

A 64-year-old nonsmoking man presented with recession defects af-fecting the facial aspect of teeth Nos. 5 and 6 and implant No. 7. Ap-proximately 3 mm of the root surfaces of teeth Nos. 5 and 6 and 3 mm of the abutment on implant No. 7 were exposed. A cement-retained fixed partial denture (FPD) was supported by implants in sites Nos. 7 and 11 (Figure 1). Teeth Nos. 5 and 6 had facial noncarious cervical le-sions (NCCLs). The straight facial probing depths were approximately 2 mm. There was no bleeding on probing. The patient reported that the recession defects had deteriorated over the previous couple of years.

The clinician discussed the findings, along with treatment plan options and risks, with the patient. Due to concerns of pain and bleeding associated with a palatal donor site, the patient elected to have the recession defects treated with connective tissue grafting using an acellular dermal matrix.

Local anesthesia was achieved using 2% lidocaine with 1:100,000 epinephrine. Intrasulcular incisions were made on the facial of sites Nos. 4 through 8 using a Bard-Parker #15 blade. The interdental papillae were not included in the incisions. Vertical incisions were made mesial to sites Nos. 5 and 7. These incisions extended from the keratinized attached gingiva into the vestibule (Figure 2). The incision mesial to site No. 5 was made larger to permit placement of two layers of ADM (AlloDerm^®, BioHorizons, biohorizons.com). The smaller incision permitted ADM alignment.

The full-thickness mucogingival tunnel was initially elevated using an Orban knife. A straight periotome was used to extend the tunnel between sites Nos. 4 and 8. Split-thickness dissection into the muco-sal tissues permitted coronal repositioning of the flap. Tension-free coronal advancement was verified. Curettes were used to clean and smooth the root surfaces. Implant surfaces had minimal plaque and calculus accumulations. Implant surface decontamination was car-ried out by burnishing using cotton pellets soaked in 3% hydrogen peroxide for 1 minute and then with sterile saline for 1 minute, so as to not damage implant surfaces. The surgical design was intended to permit placement of the grafts and coronal movement of the muco-gingival tissues without disturbing the papillae (Figure 3).

The ADM was hydrated in sterile saline for 10 minutes, as per manufacturer recommendations. Two pieces of ADM were trimmed to approximately 30 mm in length and between 5 mm and 6 mm in width (Figure 4), and layered one on top of the other. The two layers of ADM were inserted into the prepared tunnel with the connective tissue side facing facially (Figure 5). When fully inserted, the ADMs laid over the facial of sites Nos. 5 through 7. Two inter-rupted 4.0 chromic gut sutures were used to close each vertical incision site. A continuous 4.0 chromic gut suture was secured to the interdental facial gingiva between teeth Nos. 3 and 4. The suture was then passed through the facial gingiva, engaging the ADM, and passed through the teeth toward the palatal side. By weaving the suture mesially then back distally, the ADMs were secured com-pletely beneath the mucogingival tissues and in a coronal position (Figure 6). The final suture knot was tied over the original knot.

Ibuprofen (600 mg) was prescribed for discomfort. Amoxicillin (500 mg) every 8 hours for 10 days was prescribed. The patient was instructed not to brush the surgical site for 7 days. Instead, he was told to use a 0.12% chlorhexidine gluconate rinse (Peridex^™, 3M Oral Care, 3m.com) twice daily. After 7 days, remaining sutures were removed. The patient was instructed to discontinue the rinse and begin gentle brushing of the surgical site in a coronal direc-tion only. After 6 weeks, the patient was told to maintain excellent oral hygiene and was instructed in the modified Bass technique.

At 12 weeks, the surgical site was found to have healed well (Figure 7). The mucogingival tissues appeared markedly thicker and all root and abutment surfaces were covered. The patient was referred back to the referring general dentist for recall and sup-portive therapy.

Due to deterioration of other sites, the patient was referred back to the author and was seen for evaluation 3 years and 7 months after the treatment of sites Nos. 5 through 7. The treated sites were found to be healthy with 2 mm facial probing depths (Figure 8). Minimal changes in the soft-tissue architecture were noted. The abutment was exposed by 1 mm. The teeth had complete root coverage.

This case report describes the use of a lateral pouch and SCTG to correct an edentulous facial ridge deformity.10 With this technique, the graft is placed within the mucogingival pouch via an opening made by a single vertical incision. The supraperiosteal envelope is developed to treat gingival recession sites while conserving existing gingiva.7 Using this technique, the graft is teased into the envelope through the small opening created when the gingival

margin of a recession defect site is lifted. The modified tunnel technique6 was developed by combining the strengths of the lateral pouch10 and supraperiosteal envelope7 techniques. This technique uses vertical incisions on both sides of the mucogingival tunnel. The vertical incisions provide adequate clearance for the place-ment of a large graft and mobilization of the mucogingival flap while preserving the integrity of the interdental papillae. Given the space requirements to place a double layer of an ADM to treat three recession sites, the modified tunnel technique was deemed advantageous in this case.

A higher rate of complete root coverage of exposed root surfaces was reported with SCTGs having a thickness of more than 2 mm.11 Given this finding, it was postulated that use of a double layer of an ADM might also have high success rates. Success rates for root coverage using a double layer of an ADM over 4 to 5 years that com-pare favorably with sites treated with SCTGs have been reported.12

The term noncarious cervical lesion refers to the loss of tooth substance at the cervical area by wear process unrelated to dental caries.13 Clinical appearance of NCCLs can vary depending on the type and severity of the etiological factors involved.14 The CEJ serves as the reference point for the diagnosis and treatment of gingival recession defects. In some cases, however, the CEJ is not identifiable due to the presence of a NCCL.15 In the present case, the presence of crown margins made the original position of the CEJ unclear. Classification of NCCLs, for determining treatment of associated gingival recession sites and understanding potential outcomes, has been described.15,16 Understanding that NCCLs negatively affect the probability of complete root coverage is important when it comes to offering the patient realistic outcomes in managing tooth sites. In this case, complete root coverage was maintained for at least 3.5 years.

The term peri-implant soft-tissue dehiscence/deficiency (PSTD) refers to implant mucosal recession, a grayish blue hue notice-able through the mucosa and/or a discrepancy in the length of the implant-supported crown compared with a homologous natural tooth.17 A classification of PSTDs was developed to help clinicians select the optimal treatment modality.17 In the present case, the implant could be classified as a class II PSTD, subclass b. A class II PSTD has a soft-tissue margin located more apical to the ideal position of the gingival margin of a homologous natural tooth, and the implant-supported crown profile is located inside the imaginary curve line that connects the profile of the adjacent teeth at the level of the soft-tissue margins. The implant in the present case is subclass B because its mesial papilla is less than 3 mm coronal to the ideal position of the soft-tissue margin.

Using this PSTD classification system, it is recommended that the site be treated by removing the crown, modifying or changing the abutment, and using a combined prosthetic-surgical approach. Given the expense of replacing the FPD, it was decided to treat implant site No. 7 without removing the prosthesis. Despite main-taining the FPD, only 1 mm of abutment exposure was present at 3.5 years and no grayish hue was noticeable through the mucosa.

The use of a modified tunnel technique with a double layer of ADM was shown to be a successful method of treating multiple adjacent recession defects affecting teeth and an implant.

Douglas H. Mahn, DDS
Private Practice limited to Periodontics and Implantology, Manassas, Virginia