Treating Noncarious Cervical Aesthetic Zone Lesions: Using Acellular Dermal Matrix and Tunnel-Grafting Techniques

Using Acellular Dermal Matrix and Tunnel-Grafting Techniques

INTRODUCTION
A harmonious relationship between the teeth and the soft-tissue architecture is necessary to achieve a natural-appearing smile. Proper tooth size, shape, and tooth-to-tooth proportion is dependent on the gingival architecture.^1-3 Long-term success requires stable gingival margins. A thin periodontal biotype has been associated with a greater risk for developing gingival recession following surgical and restorative procedures.^4-7

Noncarious cervical lesions (NCCLs) are defects caused by the loss of dental hard tissue in the cervical part of the tooth not caused by caries. Etiologies of NCCL include erosion (chemical agents),^8,9 abrasion (physical agents),^10,11 and abfracture (occlusal forces causing tooth flexure).^12,13 A classification of NCCLs based on the depth of the cervical lesion and whether or not there is enamel involvement has been developed.¹⁴ Class I NCCLs have mild cervical defects, while Class IV have the deepest defects and loss of enamel.

Connective tissue grafting has been highly successful in achieving root coverage and increasing gingival thickness.^15-17 Tunnel techniques have reduced the risk of aesthetic problems by minimizing trauma to the interdental papillae.^18,19 Acellular dermal matrices (ADMs) have been shown to be effective in the management of multiple adjacent gingival recession defects.^20,21 Coverage of exposed root surfaces, including those with NCCLs, may be necessary to deliver aesthetic restorations with proper proportions.

The purpose of this case report is to demonstrate the use of a tunnel connective tissue grafting technique using an ADM to cover multiple NCCLs to permit proper restoration of teeth in the aesthetic zone.

CASE REPORT
Diagnosis and Treatment Planning
A 57-year-old nonsmoking female was concerned about progressive and severe gingival recession affecting her maxillary anterior teeth (Figure 1). She reported having had porcelain veneers placed 10 years earlier. To prevent tooth loss, the patient reported vigorously brushing her teeth with a hard toothbrush. The gingival recession started soon afterwards. She believed the gingival recession was a part of the aging processes and that little could be done to help the problem. The patient said she did drink soda on a regular basis, but denied bruxism.

Figure 1. Pre-op view shows teeth Nos. 6 to 11 with gingival recession, noncarious cervical lesions, and failing restorations.	Figure 2. Intrasulcular incisions were made; the interdental papillae were left intact.
Figure 3. Acellular dermal matrix (ADM), approximately 5.0 x 40.0 mm, was rehydrated in sterile saline.	Figure 4. ADM was positioned within the subgingival tunnel, with the exposed ADM yet to be covered.

Periodontal evaluation found teeth Nos. 6 to 11 to have Miller Class II to III gingival recession defects²² and Class II to III NCCLs.¹⁴ Tooth No. 9 had a full-coverage crown and a history of root canal therapy. The exposed root of tooth No. 9 had a dark shade. The exposed restoration margins were stained and failing. Probing depths were 1.0 to 3.0 mm. The patient was found to have a thin biotype. Probing the midfacial sulcus of the teeth revealed thin and translucent gingiva.

After discussing the findings, treatment options, and risks, the patient agreed to a treatment plan. First, teeth Nos. 6 to 11 would be treated with connective tissue grafting. Second, they would receive new restorations.

Figure 5. Mucogingival flap was secured over the ADM and root surfaces using a continuous suture.	Figure 6. At one week, the surgical site was healing well with complete root coverage.
Figure 7. Surgical site had healed well after 12 weeks with excellent root coverage, thicker gingiva, and natural gingival contours.	Figure 8. Re-evaluation one year after final restorations were placed, teeth Nos. 6 to 11.

Clinical Protocol
Profound local anesthesia was achieved using 2% lidocaine (1:100,000 epinephrine). Using a Bard-Parker No. 15 blade, initial intrasulcular incisions were made along the buccal surfaces of teeth Nos. 5 to 12. The interdental papillae were left intact among teeth Nos. 6 to 11 (Figure 2). An Orban knife was used to elevate a full-thickness gingival flap. Attaching gingival pouches were created facial to site Nos. 7 to 10. Only in the areas between teeth Nos. 5 and 6 and 11 and 12 was the buccal gingiva detached from the underlying interdental papillary bed. Once into the mucosal tissues, the mucogingival flap became mobile and was able to be coronally repositioned. A continuous submucosal tunnel was made that extended from teeth Nos. 6 to 11. Prominent root surfaces and root surface irregularities were reduced with manual scaling/root planing. No other root preparation techniques were employed.

An ADM (AlloDerm [BioHori­zons]) was trimmed to approximately 40.0 mm in length and 5.0 mm in height (Figure 3). The ADM was then inserted into the mucogingival tunnel where the gingiva had been detached between teeth Nos. 5 and 6. Using the Orban knife, the ADM was passed through the tunnel until it could be accessed through the gingival opening between teeth Nos. 11 and 12. The ADM was positioned in a coronal position adjacent to the cemento-enamel junction (Figure 4).

A continuous 4.0 chromic gut suture was secured to the buccal gingiva between teeth Nos. 3 and 4. By weaving this suture around the palatal of the teeth, the ADM and mucogingival flap were engaged on the buccal. The mucogingival flap was advanced and secured completely over the ADM and root surfaces. The suture was woven from the papillae, between teeth Nos. 3 and 4 to the papillae between sites Nos. 12 and 13, and then back. Each papilla between teeth Nos. 6 and 11 received 2 suture passes. The second knot was placed over the first knot over the papillae between teeth Nos. 3 and 4 (Figure 5).

The patient took ibuprofen (600 mg) every 6 to 8 hours, as needed for discomfort. The patient was prescribed amoxicillin (875 mg) every 12 hours for 10 days. The patient was instructed not to brush or floss the surgical site for 10 days. Instead, she was to rinse twice daily with 0.12% chlorhexidine gluconate (Peridex [3M ESPE]). After 10 days, the patient discontinued the rinse and began gentle tooth brushing and flossing.

At one week, the treatment sites were found to be healing well (Figure 6). Any remaining sutures were removed at this visit. The patient was instructed to gently brush the surgical site, in a downward motion with a soft bristle toothbrush, for about 5 weeks. After this, the patient was instructed to resume flossing and normal toothbrushing for one to 2 minutes using a soft bristle toothbrush. At 12 weeks, the treatment sites were found to have healed well with good root coverage, thicker gingiva, full interdental papillae, and a natural appearance (Figure 7).

The patient was then referred back to the general dentist to begin the restorative phase of her treatment.

Approximately one year after the delivery of the definitive restorations, the gingiva was found to be healthy with stable gingival margins. Periodontal probing depths were between 2.0 and 3.0 mm. Teeth Nos. 6, 7, 10, and 11 were restored with ceramic veneers (Procera [Nobel Biocare]). Teeth Nos. 8 and 9 were restored with full-coverage ceramic crowns (Procera). The patient reported being very happy with the much-improved aesthetics of her anterior teeth (Figure 8).

DISCUSSION
Winter and Allen¹⁴ classified NCCLs I through IV based on their severity of lesion depth and enamel involvement. Using this classification, Class I lesions are shallow in depth (< 0.5 mm). Class II lesions are moderate in depth (0.5 to 2.0 mm) without enamel involvement. Class III lesions are moderate in depth (0.5 to 2.0 mm) with enamel involvement. Class IV lesions are deep in depth (> 2.0 mm) with enamel involvement. Assu­ming the original veneers were placed entirely on enamel, it appears that the NCCLs in this case ranged from Class I to Class II. The appearance of the NCCL on tooth No. 9, which had a full-coverage crown, suggests the cervical portion of the rest was placed on dentin. Tooth No. 9 may have a Class III NCCL lesion. Based on the patient’s reported history of years of vigorous tooth brushing using a hard toothbrush, the primary etiology of the NCCLs was abrasion. Erosion from soda consumption may have been a secondary etiology.

The severity of gingival recession can be described using the Miller Classification.²² Miller classifications increase from I to IV as the gingival recession defects extend past the mucogingival junction and with the amount of interdental attachment loss. As the severity of the gingival recession defect increases, less root coverage is anticipated with connective tissue grafting. The amount of root coverage that may be expected given the anatomic conditions has been described as the maximum root coverage level (MRC).²³ In this case, the teeth ranged from Miller Class I to III. The canines and central incisors had the greatest amount of gingival recession.

Zucchelli et al²⁴ proposed a decision-making process for treating NCCLs associated with gingival recession defects based upon the topographic relationship between the MRC and NCCL. In this case series study, 5 NCCL types categorized gingival-NCCL defects. The NCCL type 1 defect had the MRC > 1.0 mm to the most coronal extension of the NCCL. The NCCL type 5 defect had the MRC located at the level or apical to the most apical extension of the NCCL. This study recommended that NCCL type 1 defects be treated exclusively periodontally. NCCL type 5 defects should be treated exclusively restoratively. Considering the amount of root coverage achieved, the teeth treated in this case would be categorized NCCL types 1 and 2. The primary purpose of the restorations was not to cover root surfaces, but to restore the teeth with well properly fitting and aesthetic restorations.

A thin gingival biotype has been associated with a greater risk of developing gingival recession following surgical and restorative procedures.^4-7 One method of assessing the gingival biotype is with a visual measurement using a periodontal probe.^6,7 If the periodontal probe color can be seen through the gingival collar, the gingival biotype is considered thin. While this method is subjective and can only identify gingiva as being thick or thin, it has been shown to have a high degree of reliability.⁷ In this case, probing the gingival sulcus indicated a thin biotype. Given the NCCL classifications, Mil­ler classifications, and thin gingival biotype, this case was deemed aesthetically challenging.

Connective tissue grafting ad­dresses 2 restorative goals. First, connective tissue grafting increases the thickness of the facial gingiva. This effectively transforms a thin biotype to a thicker biotype.^6,7 ADMs are supplied with a uniform thickness be­tween 0.89 and 1.65 mm. Second, connective tissue grafting is an effective method of achieving root coverage.^16-18 The use of connective tissue allografts permits treatment of multiple adjacent teeth.^20,21 Tunnel techniques further enhance the aesthetic results by protecting the interdental papillae.^25-29 The handling characteristics and uniformity of the ADM makes it an ideal material for use with a tunnel technique.^25-29 In this case, the use of an ADM with a tunnel grafting technique resulted in the desired root coverage and increased gingival thickness without shrinkage of the interdental papillae.

Similar to clinical crown lengthening cases, the area was allowed to heal for 12 weeks before tooth preparation and impression taking was permitted. Lanning et al30 found the position of the free gingival margin, attachment, and bone levels re­mained stable between 3 and 6 months. They did note, however, that healing must be closely monitored and that positional changes could occur beyond 6 months.

CONCLUSION
The use of an ADM with a tunnel-grafting technique can be an effective method of covering root surfaces with NCCLs. In the aesthetic zone, this treatment modality can be used to develop a soft-tissue architecture that will permit delivery of restorations that are natural in appearance.

Acknowledgement
The final restorations delivered by Thomas Sentz, DDS, Warrenton, Va.

References

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Dr. Mahn is a periodontist in private practice in Manassas, Va. He graduated from the State University of New York at Stony Brook Dental School in 1990 and completed his periodontal residency at the Medical College of Virginia, School of Dentistry in 1992. He also completed a residency on temporomandibular disorders/orofacial pain at New York University College of Dentistry in 1996. His practice emphasizes perioplastic, regenerative, and dental implant therapies. He has participated in many publications and has lectured on these topics. In 2004, he was listed in Washingtonian Magazine’s Best Dentists List. He can be reached at (703) 392-8844 or via email at dmahn@cox.net.

Disclosure: Dr. Mahn reports no disclosures.