Comparative evaluation of the effectiveness of acellular dermal matrix allograft and subepithelial connective tissue to coronally advanced flap alone in the treatment of multiple gingival recessions: A clinical study.

BACKGROUND: Obtaining predictable and esthetic root coverage has become an important part of periodontal therapy. Several techniques have been developed to achieve these goals with variable outcomes. The aim of this study was to appraise the effectiveness of acellular dermal matrix allograft (ADMA) and subepithelial connective tissue graft (SCTG) compared to coronally advanced flap (CAF) in the treatment of multiple gingival recessions.
MATERIALS AND METHODS: A total of 30 patients aged between 18 and 50 years, with multiple Miller's Class I and II recessions on labial or buccal surfaces of teeth were selected for this study. The patients were randomly assigned to CAF + ADMA, CAF + SCTG and CAF groups with 10 patients in each group. The clinical parameters assessed were probing pocket depth (PPD), clinical attachment level (CAL), gingival recession (GR), width of keratinized tissue, plaque index and papilla bleeding index at base line and 6 months after surgery.
RESULTS: Statistical analysis using One-way ANOVA suggested that the root coverage obtained was greater in the ADMA + CAF (89.83 ± 15.29%), when compared to SCTG + CAF (87.73 ± 17.63%) and CAF (63.77 ± 27.12%) groups. The predictability for coverage of >90% was greater in CAF + ADMA (65%) when compared with SCTG + CAF (61.66%) and CAF (31.17%). Improvements in the clinical parameters from baseline were found in all the three groups treated.
CONCLUSION: It was concluded that all three techniques could provide root coverage in Miller's class I and II gingival recessions; but greater % root coverage and predictability for coverage of >90% could be expected with CAF + ADMA and CAF + SCTG groups when compared with CAF alone.

RCT Entities:   Population Interventions Outcomes

INTRODUCTION

Root coverage procedures are frequently indicated to resolve a variety of patient-centered concerns including, but not limited to, root sensitivity, increased potential for root caries, difficulty in plaque control and esthetics.[1]

The coronally advanced flap (CAF) to cover denuded root surfaces has been considered to be a simple (because donor tissue does not need to be procured) and predictable method (a reported root coverage between 70% and 99%)[2] at both single and multiple recession sites with apparently satisfactory esthetic results.[3] The use of subepithelial connective tissue graft (SCTG) covered by a CAF has shown good predictability in the correction of multiple gingival recessions with mean root coverage ranging from 84% to 100%.[45] However, it involves a certain degree of patient morbidity because of two surgical sites.

The use of an acellular dermal matrix allograft (ADMA) as a substitute for palatal donor sites to increase the keratinized tissue (KT) around teeth, in addition to the treatment of alveolar ridge deformities and root coverage procedures has been reported in the literature. In vitro and clinical studies have suggested that ADMA is an acellular, nonimmunogenic scaffold that heals by repopulation and revascularization, rather than through a granulation process.[67] Previous studies have compared the results obtained with ADMA and the SCTG for the treatment of gingival recessions. However, no significant difference in recession reduction between the procedures was reported., Conversely, a study has shown that the SCTG produced a greater mean probing reduction and mean keratinized tissue increase than the ADMA.[8]

Within the limits of our knowledge, the effectiveness of CAF alone in the treatment of multiple gingival recessions has not been compared with that of CAF + SCTG and CAF+ ADMA procedures. Hence, the aim of the present controlled, parallel design study was to clinically evaluate the treatment of gingival recessions (Miller class I and II) by CAF alone or with either an ADMA or SCTG.

MATERIALS AND METHODS

Thirty systemically healthy patients aged 18–50 years (mean 29.7 ± 4.35 years) with multiple gingival recession defects, on labial or buccal surfaces of the teeth, classified as either Miller's class I or II, were selected among those seeking care at the Department of Periodontics, Sharad Pawar Dental College and Hospital, Wardha. Inclusion criteria used were the presence of >2 mm recession depth with a loss of clinical attachment level (CAL) >4 mm, having equal amount of keratinized gingiva apical to the recession and a radiographic evidence of sufficient interdental bone (distance between the crestal bone and the cementoenamel junction [CEJ] as < 2 mm). Patients’ agreed to participate in the study and gave their informed consent. The University's (Datta Meghe Institute of Medical Sciences University, Nagpur) Ethical committee approved the consent form and the study protocol.

Patients using tobacco in any form, uncooperative, with unacceptable oral hygiene after Phase I therapy, and with a history of periodontal surgery were excluded from the study. Recession defects associated with caries or restorations, as well as teeth with pulpal pathology, were excluded. Information concerning dietary status, systemic background, mouth cleaning habits, gingival and periodontal status along with other routine clinical data were recorded in the specially designed chart.

Full mouth plaque score was obtained by using Turesky-Gilmore-Glickman modification of Quigley-Hein (1970)[9] plaque index (PI), which revealed the presence of plaque. Full mouth bleeding score was obtained by using papillary bleeding index (PBI)[10] at baseline, 3 months and 6 months after surgery.

Study design

This study was a randomized, controlled, parallel designed, clinical study performed over a period of 6 months. Thirty patients with a total of 73 recession defects, with a minimum of 2 recession defects per patient were found suitable. The subjects were randomly assigned to CAF + ADMA, CAF + SCTG and CAF groups by computer generated tables, with 10 patients in each group. CAF + ADMA group (mean age 30.8 years, M: F 8:2) with 21 recession defects, CAF + SCTG group (mean age 23.5 years, M: F 8:2) with 23 recession defects and the CAF group (mean age 30.3 years, M: F 7:3) with 29 gingival recession defects were treated.

Initial therapy

Following selection, all patients were monitored in oral hygiene and instructed in proper toothbrushing, with roll-stroke technique being prescribed for teeth with recession-type defects. In order to achieve a regular and smooth surface, scaling and selective root planing were carried out. Coronoplasty was performed if required. At the end of therapy, before the surgical procedure, all patients had a plaque score of <1 and bleeding score of <1.

Clinical assessments

One calibrated examiner collected the following data at baseline, 3 months and 6 months postoperatively on the mid-facial aspect of the study tooth: Relative gingival margin level (RGML), probing pocket depth (PPD) and relative attachment level (RAL) with a computerized constant pressure probe that is, Florida disk probe (Florida probe corporation, Gainesville, FL, USA) with a constant force of 15 g (pressure-154 N/cm2), tip diameter of 0.40 mm, precision of 0.1 mm and a probe length of 20 mm. The RAL was recorded by placing the tip of the Florida probe at the base of the pocket and the disk base resting on the occlusal surface, the distance recorded as RAL. The distance from the occlusal level to the gingival margin was considered as RGML. The probing depth (PPD) was calculated by subtracting the RGML from RAL. GR was measured as the distance from the CEJ to the gingival margin with a William's graduated probe and width of keratinized tissue (WKT) was measured as the distance from the most apical point of the mucogingival junction to the gingival margin with a William's graduated probe.

Surgical procedure

Prior to the surgical procedure, intraoral asepsis was performed with 0.2% chlorhexidine gluconate (Hexidine - ICPA Health product Ltd, India) for 1 min. After local anesthesia (2% Lidocaine with adrenaline 1:100,000), the exposed root surfaces were planed with curettes and ultrasonic instruments. An intrasulcular incision was made with a #15C (Ribbel, New Delhi, India) blade on the buccal aspect of the involved teeth and extended horizontally to adjacent interdental areas. Two oblique releasing incisions were made from the mesial and distal extremities of the horizontal incision beyond the mucogingival junction. The trapezoidal mucoperiosteal flap was raised up to the mucogingival junction, after which a partial thickness flap was extended apically, as far as necessary, and hence that it could be coronally repositioned, at the CEJ, without tension. The facial portions of the interdental papillae were deepithelized to create a connective tissue bed. Abundant sterile saline irrigations were performed during the procedures. The flap was displaced coronally, without tension, to the CEJ level fully covering the recession. A 4-0 nonresorbable silk surgical suture (Ethicon, Johnson and Johnson Ltd., Somerville, NJ, USA) was used to secure the CAF at the CEJ level by utilizing horizontal suspension suturing technique. Interrupted sutures were placed to coapt the mesial and distal papillae as well as the lateral aspects of the flaps along the vertical incisions, and to facilitate tissue stabilization.

For the ADMA (Alloderm, Lifecell Corporation, New Jersey) and SCTG sites the procedures were identical to the one described, with the exception of addition of ADMA or CT graft. A CT graft in the proper dimensions (as measured with a template) was harvested from the palate (canine to first molar area) using the trap door approach[11] and trimmed as necessary after removal of excess fatty and glandular tissue. The graft dimensions were determined by the distance between the vertical incisions and by the distance of approximately 2–3 mm from the gingival margin. The flap was then repositioned to completely cover the donor site and sutured with 4-0 silk surgical sutures.

The CT graft was placed immediately over the exposed root (s) covering the entire defect and the adjacent recipient bed and sutured to the interdental papilla with 5-0 Vicryl [Ethicon, Johnson and Johnson, Waluj, Aurangabad, India] sutures. It was then covered with the CAF. The tissue flap was then positioned coronal to the CEJ and sutured using 4-0 nonabsorbable silk surgical sutures. Interrupted sutures were placed laterally, and continuous sutures coronally [Figures 1–5].

Figure 1

Clinical photograph showing preoperative recession in the coronally advanced flap and subepithelial connective tissue graft group

Figure 5

6 months postoperative photograph

Graft harvested from donor site

Suturing of the connective tissue graft at the recipient site

Flap coronally positioned and sutured

In the ADMA group, an ADMA was adapted after being aseptically rehydrated in sterile saline, according to manufacturer's instruction. A template was prepared and the graft was trimmed to a shape and size of the template designed to cover the root surface and the adjacent surrounding bone. The basement membrane side was placed adjacent to bone and tooth and connective tissue side was placed facing the flap. The coronal, lateral borders of ADM were sutured with sling sutures using resorbable sutures (Vicryl 5-0). The flap was coronally positioned and sutured with nonresorbable silk sutures (Ethicon 4-0) to completely cover the allograft [Figures 6–10].

Figure 6

Clinical photograph showing preoperative recession in the coronally advanced flap and acellular dermal matrix allograft group

Figure 10

6 months postoperative photograph

Measurement with tin foil at recipient site

Acellular dermal matrix allograft sutured at the recipient site

Flap coronally positioned and sutured

Postsurgical care

Postsurgery periodontal dressings (COE-PAK™, GC America Inc., ALSIP, IL, USA) were placed at the recipient sites. Patients were advised to discontinue all mechanical oral hygiene measures for 4 weeks and avoid any trauma to the surgical sites. Analgesics (Ibugesic - Ibuprofen and Paracetamol) were prescribed as required. A 0.2% chlorhexidine gluconate mouthwash was prescribed twice daily for 4 weeks.

One week postsurgery the periodontal pack was removed. All nonresorbable sutures were removed after 2 weeks. The areas were professionally cleaned as a supragingival prophylaxis was performed with a rubber cup at low speed and by using a prophylaxis paste, weekly, for 4 weeks and then monthly till the end of the study period. At 3 weeks, brushing was reinstituted with a soft toothbrush utilizing charter's method of brushing.

Statistical analysis

Statistical analysis was performed using statistical software (SPSS version 15.0, SPSS, Chicago, USA). Power analysis indicated more than 80% power. Results on continuous measurements were presented as mean ± standard deviation and results on categorical measurements were presented in number (%). Significance was assessed at 5% level of significance. Comparisons of the PI and PBI at baseline, 3 months and 6 months were made by Students paired t-test. If P > 0.05, the difference observed was considered nonsignificant and if <0.05, was considered statistically significant for all analyses. Repeated measures-ANOVA was used to make comparisons of various parameters used, from baseline to 6 months. Comparisons between multiple groups were done by One-way ANOVA, followed by nonparametric multiple comparison post-hoc Tukey's test. The mean intraexaminer standard deviation of differences in repeated PD measurements and CAL measurements were obtained using single passes of measurements with a UNC-15 probe (Hu-Friedy, Chicago, IL, USA) (correlation coefficients between duplicate measurements; r = 0.95).

RESULTS

In the CAF + ADMA group, 20 recession defects (16 were located on mandibular incisors, 2 on mandibular canine and 2 on maxillary premolar) were treated. Furthermore, in CAF + SCTG group 23 recession defects (17 were located on mandibular incisors, 3 on mandibular premolars and 3 on mandibular canine) were treated and in the CAF group, 29 recession defects (11 were located on mandibular incisors, 3 on maxillary premolars, 6 on mandibular canine, 2 on maxillary incisors, 3 maxillary canine and 4 on mandibular premolars) were treated.

All the patients tolerated the surgical procedures well, experienced no postoperative complications, and complied with the study protocol. PI scores remained below score 1 (P < 0.05) and a statistically significant reduction in PBI scores from baseline to 6 months were observed [Table 1]. Statistically significant changes from baseline were found for all the parameters in all the three groups. Moreover, when the techniques were compared at 6 months, the difference was significant in favor of the CAF + ADMA and CAF + SCTG groups when compared with CAF alone [Table 2].

Table 1

Comparison of clinical parameters at baseline and 6 months follow-up in ADMA + CAF, SCTG + CAF and CAF groups (MV + SD; in mm)

Table 2

Comparison of clinical parameters at baseline, 3 months and 6 months follow-up in ADMA + CAF, SCTG + CAF and CAF groups (MV + SD; in mm)

In the CAF + ADMA group, a statistically significant reduction of gingival recession from baseline was found [Table 2] corresponding to mean root coverage of 89.83 ± 15.29% [Table 3]. In the SCTG + CAF group, a mean change in recession of-86.5 from baseline was found [Table 2]. This result was statistically significant and corresponded to mean root coverage of 87.73 ± 17.63% [Table 3]. However, in the CAF group a mean change in gingival recession of only − 61.7 [Table 2] (statistically significant) was seen corresponding to mean root coverage of 63.77% ±27.12% [Table 3].

Table 3

Comparison of percentage root coverage in three groups of patients studied

At 6 months, when the results were compared, mean reduction in the gingival recession and root coverage were significantly greater in the CAF + ADMA group when compared with the CAF group. Similarly, when comparison was made between CAF + SCTG and CAF groups, the results were in favor of the CAF + SCTG group [Tables 2 and 3]. When comparisons between CAF + ADMA and CAF + SCTG groups were made, a higher recession reduction and greater root coverage was demonstrated in the CAF + ADMA group, the difference, however, was not statistically significant.

In all the three groups, the mean PPD reduction when compared to baseline was statistically significant [Table 2]. However, when intergroup comparisons were made at 6 months, the differences were not statistically significant [Table 2].

A statistically significant gain in the attachment was seen in all the three groups studied when compared to the baseline [Table 2]. When the mean attachment gain in the CAF + ADMA group was compared to CAF, significantly higher gain was found in the CAF + ADMA group [Table 2]. Similarly, when the mean attachment gain in CAF + SCTG group was compared to CAF group, it was significantly higher in CAF + SCTG group [Table 2]. The results did not reach a level of statistical significance when comparison was made between CAF + ADMA and CAF + SCTG groups [Table 2].

An increase in WKT was found in all the treated groups from baseline [Table 2]. At 6 months, the mean increase in WKT in both the CAF + ADMA and CAF + SCTG groups were greater than in CAF group and the differences were statistically significant [Table 2]. However, when comparison of WKT increase between CAF + ADMA and CAF + SCTG groups were made at 6 months, the result was statistically significant in favor of the CAF + SCTG group [Table 2].

In the CAF + ADMA, CAF + SCTG and CAF groups, on average 89.83% ±15.29%, 87.73% ±17.63% and 63.77% ±27.12% respectively, of the root surfaces initially exposed due to recession were covered with soft tissue at 6 months postsurgery. The predictability for coverage of > 90% was 65% ± 33.75% that is, 13 of 20 defects in CAF + ADMA, 61.66 + 45.85% that is, 15 of 23 defects in CAF + SCTG, and 31.17% ± 42.93% that is, 9 of 29 defects in CAF groups. The number and mean percentage of the defects with complete root coverage were statistically significant in all the three groups at 6 months follow-up. The percentage of root coverage in all groups is shown in Table 3. Moreover, the number of defects with more than 3 mm recession reduction was found to be greater in CAF + ADMA group when compared to CAF + SCTG and CAF groups [Table 4].

Table 4

Comparison of GR reduction in three groups of patients studied

DISCUSSION

When multiple gingival recession defects affecting adjacent teeth are present in the esthetic areas of the mouth, they have to be treated at the same time to achieve the best esthetic results.[12] The experimental design in the present study included three groups, treated by CAF in multiple recessions differing only by the presence of either an ADMA (currently not available in India) or SCTG. Considering the group's homogeneity at baseline, the differences in the clinical outcome can be attributed to the treatments employed. A statistically significant reduction in the PI and PBI scores, from baseline, was found in all the three groups.

Until date, although robust body of evidence exists regarding the use of CAF for single recession defects,[13] very few studies are currently available on the use and the outcomes of CAF for the treatment of multiple gingival recessions.[141516] A systematic review[13] on the treatment of recession by CAF reported better results for CAF + SCTG than CAF alone, when the outcome variables considered were complete root coverage and recession reduction. These findings were similar to the results in this study. In reports of studies of at least 6 months duration with a minimum of 10 patients per group,[17] the range of defect resolution in sites treated with CAF was 55% to 98% (mean 77%), while for CAF + SCTG treated sites it was 52–99% (mean 82%). The root coverage of 87% in CAF + SCTG group and 63% in CAF group in the present study falls within the range of these aforementioned studies.[17] In addition, all the studies considered in the systematic review reported better outcomes in terms of CAL gain and increase in the width of keratinized gingiva for CAF + SCTG when compared to CAF alone[13] as in the present study.

When CAF + ADMA and CAF groups were compared in terms of recession reduction, greater reduction was found in the CAF + ADMA group when compared to CAF alone. These reports are comparable to those reported by several studies, which have compared CAF + ADMA and CAF in multiple gingival recessions.[181920] However, recently a systematic review reported non-significant difference between the two, taking into consideration two studies[1921] comparing the two procedures. The predictability of root coverage of >90% for the CAF + ADMA group was 65% in the present study; whereas, a predictability of 72% has been reported[22] based on several published articles on ADMA.

When the root coverage obtained was compared between CAF + ADMA and CAF + SCTG groups, greater coverage was obtained in CAF + ADMA (89.83%) group when compared to CAF + SCTG (87.73%). However, the results were not statistically significant. These results are comparable to those obtained in previous studies.[2324]

The results in the present study indicate that all the three treatment modalities, CAF, CAF + SCTG and CAF + ADMA groups showed good improvement in the studied clinical parameters with respect to baseline, indicating that all the three procedures can be used in clinical practice. The root coverage obtained in this study was found to be greater in CAF + ADMA (89.83%) group when compared to both CAF + SCTG (87.73%) and CAF (63.77%) groups. The root coverage obtained in both CAF + ADMA and CAF + SCTG groups were greater than that obtained with CAF alone, and the results were statistically significant. The observations are in accordance with several reported studies comparing the use of CAF alone, with either CAF + ADMA[1921] or CAF + SCTG.[1625] At present, within the limits of our knowledge, there are no reported studies comparing the effectiveness of all the above mentioned three procedures in the treatment of multiple gingival recession defects.

The gain in CAL was found to be greater in the CAF + ADMA group when compared to CAF + SCTG and CAF groups. The type of healing obtained between the soft tissue and the denuded root surface can be only speculated on, since no histological evaluations are available. Animal studies have demonstrated that new connective tissue attachment is made up of 44-50% of the successfully covered recession defects following the use of ADMA with CAF procedures.[26] Although, the observed clinical changes probably represent a combination of new connective tissue attachment in the apical half of the defect and long junctional epithelium in the coronal half as reported in previous histological studies on ADMA[26] and SCTG.[27] Furthermore, the treatment procedures in the present study did not result in the formation of deep periodontal pockets (mean PPD in CAF + ADMA = 0.80 mm, CAF + SCTG = 0.81 mm, and CAF = 0.72 mm).

In the present study, all the treatment groups resulted in significant increase in the WKT. The CAF + SCTG showed significantly greater increase in the WKT of 2.21 mm, when compared to CAF + ADMA (1.6 mm) and CAF (1.00 mm) groups. However, since there are no reported studies comparing the three treatment procedures, we can take into account studies that have compared CAF + SCTG and CAF + ADMA,[2328] which have reported a significant increase in keratinized tissue in the CAF + SCTG group, similar to the findings in the present study. Furthermore, it has been reported that ADMA resulted in the lesser extent of attached gingiva due to considerable shrinkage during healing.[29]

CONCLUSION

It can be said that all three techniques could provide root coverage in Miller's class I and II gingival recessions; nonetheless a greater % of root coverage and predictability for coverage of >90% can be expected with CAF + ADMA and CAF + SCTG groups when compared with CAF alone.