Coronally advanced flap with and without platelet-rich fibrin in the treatment of multiple adjacent recession defects: A randomized controlled split-mouth trial.

BACKGROUND: The objective of our study was to evaluate and compare the effectiveness of coronally advanced flap (CAF) with or without the use of platelet-rich fibrin (PRF) membrane in the treatment of multiple adjacent recession defects (MARD) clinically and by cone-beam computed tomography (CBCT).
MATERIALS AND METHODS: Twenty healthy patients having 75 MARD were allocated randomly to CAF with orthodontic button group (CAFB) or CAFB + PRF membrane group (CAFB + PRF). Clinical parameters such as gingival recession depth (GRD), probing depth (PD), and keratinized tissue width (KTW) were calculated at baseline, 3 months, and 6 months. The distance from the facial alveolar crest of bone to gingival margin bone and gingival thickness (GT) at three different points were assessed by CBCT at baseline and 6-month postsurgery. Esthetic outcome and postoperative discomfort were evaluated using root coverage esthetic score and visual analog scale, respectively.
RESULTS: Percent root coverage achieved in CAFB category was 93.17% ± 13.23% and that in CAFB + PRF group was 95.68% ± 10.13% at 6 months, with no notable difference. Similarly, no difference was found in either group in GRD reduction, PD, and CAL postoperatively. Use of PRF resulted in statistically highly significant (P < 0.001) increased GT at 6 months' time point as compared to participants treated with CAF without PRF, which indicates clinical and esthetic benefits achieved through the procedure.
CONCLUSIONS: CAFB can be used successfully to treat MARD with predictable outcome. Additional benefit in terms of gain in KTW and GT can be achieved when PRF membrane is used as an adjunct.

INTRODUCTION

Gingival recession is exposure of root surface of the tooth due to the apical migration of the marginal gingiva[1] Various risk factors related to gingival recession such as tooth malposition, alveolar bone dehiscence, frenal pull, and improper oral hygiene habits.

Although connective tissue graft (CTG) is an ideal approach, platelet-rich fibrin (PRF) can be used as an alternate means by keeping in mind the requirement of the second surgical site. Requirement of large amount of graft for treating multiple recession sites also makes CTG difficult and challenging treatment option.[2] The natural polymerization process in the preparation of PRF enables entrapment of growth factors, platelets as well as cytokines in the dense fibrin matrix, allowing release of growth factors for longer duration, enhancing both hard- and soft-tissue (ST) healing.[34] The fibrin clot protects the graft material and acts as a bond between all the bone particles. An added advantage of PRF is the existence of leukocytes and various cytokines that permits the self-modulation of the infectious and inflammatory processes.[1]

The position of marginal gingiva, at the end of the surgical procedure, appeared to be fundamental in attaining complete root coverage (CRC).[5] To achieve the maximum possible coronal positioning of the gingival margin (GM), suspending the sutures at contact point by placing composite stops interproximally or suspending the sutures with the help of orthodontic buttons bonded on the tooth have been used.[67] Composite stops have been used by various authors in the past to aid in the advanced GM location postsurgically.[89] However, the composite material does not work well in areas of the mouth where it is difficult to keep the tooth dry. Maroo et al. in their ortho-perio amalgamation study showed postoperative results of coronally advanced flap (CAF) combination with orthodontic button to be very successful amalgamation, even in cases of Miller's Class III recession.[10]

In mucogingival surgeries, initial gingival thickness (GT) is a critical factor related to CRC.[11] Techniques to measure GT, such as using needles, periodontal probes, ultrasonic devices, and parallel profile radiograph,[1213] have been questioned for reliability and applicability. Fu et al. compared and correlated clinical and cone-beam computed tomography (CBCT) measurements of ST along with bone thickness and found it as a reliable depiction of the thickness of labial gingiva as well as bone.[14] Januário et al. introduced a simple technique for measuring the GT and dimension of dentogingival unit using ST-CBCT.[15] This technique presents a clear visualization of both soft as well as hard periodontal anatomical structures.

The present study was planned to evaluate and compare the efficacy of CAF plus orthodontic button application (CAFB) with and without PRF membrane for the surgical therapy of multiple adjacent recession defects (MARD) clinically and by CBCT.

MATERIALS AND METHODS

Twenty patients, aged 22–47 years, were selected on a successive basis and treated at the department of periodontics and implantology between June 2016 and December 2017. The research protocol was reviewed and accepted by the Ethics Committee of the Institute. Written informed consent was obtained from all the patients (Clinical Trials Registry–India, CTRI/2017/10/010148).

Sample size was calculated with an expected parameter (percentage of complete root coverage- CRC) with estimate difference of 23.6% ratio of root coverage between Group I and Group II.[6] The minimum sites required were 69 with relative precision of 10% and 95% confidence level.

Patients were enrolled on the basis of following inclusion criteria: Systemically healthy participants with adjacent multiple Millers Class I or II gingival recession in the maxillary anterior region (15–25) with ≥1 mm of attached gingiva and probing depth (PD) of <3 mm at gingival recession sites with presence of identifiable CEJ.[16] Patients with the history of any systemic disease or drug usage, smokers, recession defects associated with caries and pulpal pathology, pregnant or lactating mothers, and periodontal therapy performed in the past 6 months were excluded from this trial.[171819]

The patients were randomly allocated by computer-generated random numbers into two treatment groups. The participants in Group I were allocated to CAF and orthodontic button treatment protocol, whereas the participants in Group II were treated by CAFB with PRF (CAFB + PRF).

Presurgical therapy

Initial visits consisted of oral hygiene instructions, ultrasonic scaling, and polishing, carried out a month before surgery in both the groups. For assessment of oral hygiene and overall gingival health, Plaque Index[20] and Gingival Index[21] Scores were obtained at all time intervals. Following clinical parameters were recorded at all time intervals postsurgery:

(1) Gingival recession depth (GRD) calculated as distance between the apical-most point of the CEJ and GM, (2) PD calculated as the distance from GM to the base of the gingival sulcus, (3) clinical attachment level (CAL) calculated as the distance from the CEJ to the bottom of the sulcus and (4) apicocoronal width of keratinized tissue (KTW) measured as the distance from the mucogingival junction (MGJ) to the GM, with the MGJ location determined using a visual method. These measurements were calculated using periodontal probe (PCP-UNC 15 periodontal probe, Hu-Friedy, Chicago, IL). Percentages of mean root coverage (MRC) and CRC were determined at 3 and 6 months after surgery according to standard formulae.[22]

Cone-beam computed tomography analysis

CBCT readings were taken for both the groups at baseline and 6 months on CBCT scans (KODAK 9000C 3D Extraoral Imaging System, Carestream Health, Rochester, NY, USA), analyzed in the parasagittal section.

The parameters measured on CBCT included:

Distance from facial alveolar bone crest to GM bone (GMB) [Figure 1a]. This was measured on the facial aspect of the tooth parallel its long axis

Figure 1

Cone-beam computed tomography measurements. (a) Gingival margin bone-distance of the facial alveolar bone crest to the gingival margin. (b) Gingival thickness 1-gingival thickness measured 1 mm apical to the alveolar bone crest. Gingival thickness 2-gingival thickness measured at the alveolar bone crest. Gingival thickness 3-gingival thickness measured 1 mm coronal to alveolar bone crest

Facial GT was measured on facial aspect at three different points:

GT1 was measured 1 mm apical to crest of alveolar bone, GT2 at alveolar bone crest, and GT3 at 1 mm coronal to alveolar crest [Figure 1b]. These measurements were performed perpendicular to the long axis.

Surgical procedure

In both groups, before beginning the surgery, orthodontic buttons (Zhejiang Protect Medical Equipment Co., Ltd., Zhejiang Province, China) were placed on all the teeth with GRD with dental composite which was light cured.

Group I – CAF procedure as illustrated by Zucchelli et al. in 2009,[23] a modification for MARD of the protocol described by De Sanctis and Zucchelli[24] for isolated recession defects was adopted in Group I (Control group). The technique involves a split-full-split thickness flap design [Figure 2]. For suturing, 5–0 resorbable sutures were used. At the beginning, two interrupted periosteal sutures were placed at apical-most extension of the vertical releasing incision which proceeded coronally with remaining interrupted sutures; it proceeded coronally with other interrupted sutures (Nylon monofilament, Ethicon, Johnson and Johnson, Woluwe, Belgium). Sling sutures were placed to suspend the center portion of the flaps on the orthodontic buttons and for stabilization of each and every papilla over the interdental connective tissue region

Figure 2

Surgical procedure in coronally advanced flap with orthodontic button group. (a) Patient from coronally advanced flap with orthodontic button group with baseline multiple gingival recession. (b) Orthodontic buttons applied. (c) Oblique incisions and creation of new surgical papillae. (d) Elevation of split-full-split thickness flap. (e) Coronal advancement of the flap by suspended sutures around the orthodontic button at teeth. (f) Periodontal dressing applied. (g) Three months follow-up. (h) Six months follow-up

Group II – For test group, just before surgery, intravenous blood was collected in a 10-ml test tube and a PRF membrane was prepared. Standard PRF was prepared according to Choukroun's PRF protocol. The surgical protocol applied at test sites was same as that applied for the control group. After reflection of the flap, the previously prepared PRF membrane[3] was placed on the recession defects, immediately below the CEJ. The flap was coronally advanced and sutured [Figure 3].

Figure 3

Surgical Procedure in coronally advanced flap with orthodontic button + platelet-rich fibrin group. (a) Patient from coronally advanced flap with orthodontic button + platelet-rich fibrin group with baseline multiple gingival recession. (b) Orthodontic buttons applied. (c) Oblique incisions and creation of new surgical papillae. (d) Elevation of split-full-split thickness flap and placement of platelet-rich fibrin membrane. (e) Coronal advancement of the flap by suspended sutures around the orthodontic button at teeth. (f) Periodontal dressing applied. (g) Three months follow-up. (h) Six months follow-up

Postoperative care

The patients were advised to take analgesic (Ibuprofen 400 mg) thrice daily for 5 days and antibiotics (amoxicillin 500 mg) thrice every day for 5 days postsurgery and instructed to refrain from brushing and flossing at surgical site until removal of sutures.[25] They were also instructed to rinse with chlorhexidine mouthwash (0.12%) twice daily for a period of 1 month. The suture removal was done after 14 days postsurgery.

Postsurgical evaluation

Postsurgery discomfort and esthetics were evaluated on a 10 cm visual analog scale (VAS).[26] VAS scores for pain and VAS esthetic score was evaluated at 1 week and 6 months, respectively. The patient satisfaction with overall treatment outcomes was 8 on VAS scale ranging 1 (not pleased) to 10 (very pleased). Root coverage esthetic score was assessed at 6 months.[27]

Statistical analysis

The data were analyzed using STATA 14.0 version (StataCorp LP, Texas, USA). P < 0.05 was considered statistically significant. Descriptive statistical analysis was described using mean ± standard deviation for all the study parameters. GRD, PD, CAL, and KTW were compared at different time period by performing repeated one-way ANOVA test. Multiple comparisons were performed by applying Bonferroni multiple test. CBCT parameters GMB, GT1, GT2, and GT3 were compared between baseline and 6 months by performing paired t-test and difference between these parameters between Group I and Group II were assessed by utilizing independent t-test. MRC and CRC were compared between Group I and Group II by applying independent t-test.

RESULTS

A total of 20 patients (16 males and 4 females) with the mean age of 32.6 years were treated in this clinical trial. Group I and II included 150 MARD which were treated by CAFB and CAFB + PRF, respectively. The results of our study show statistically increased width of keratinized tissue (KTW) and gingival tissue thickness (GT). The results demonstrated highly significant mean reduction in the GRD for the surgical sites at 3 and 6 months in the test and control groups as against baseline measurements; however, intergroup difference was nonsignificant [Table 1]. In Group I, mean KTW obtained: 2.56 ± 0.49 mm at baseline, 3.21 ± 0.50 mm at 3 months, and 3.44 ± 0.64 mm at 6 months. In Group II, mean KTW: 2.48 ± 0.52 mm at baseline, whereas it was 3.34 ± 0.60 mm and 3.62 ± 0.61 mm at 3 and 6 months, respectively. A significantly increased KTW was seen in Group II as compared to Group I at 3 months and 6 months [Table 1]. In Group I, MRC was 79.49% ± 21.83% and 93.17% ± 13.23% at 3 and 6 months, respectively. In Group II, the MRC was 80.15% ±19.65% at 3 months and 95.68% ± 10.13% at 6 months, respectively [Table 2].

Table 1

Clinical and radiographic parameters at various time intervals in Group I and Group II

	Group I (n=75)	Group II (n=75)	P
GRD (mm)
Baseline	2.93±0.77	2.98±0.76	0.6896
3 months	0.73±0.72	0.62±0.71	0.1423
6 months	0.21±0.41	0.17±0.38	0.4022
PD (mm)
Baseline	1.70±0.26	1.69±0.46	0.8700
3 months	1.45±0.50	1.42±0.49	0.6894
6 months	1.34±0.47	1.37±0.48	0.9950
CAL (mm)
Baseline	4.64±0.72	4.66±0.77	0.8697
3 months	2.18±0.83	2.08±0.74	0.0716
6 months	1.56±0.62	1.53±0.52	0.6805
KTW (mm)
Baseline	2.56±0.49	2.48±0.52	0.3338
3 months	3.21±0.50	3.34±0.60	0.0412¶
6 months	3.44±0.64	3.62±0.61	0.0309¶

¶Statistically significant (P<0.05). All values presented as mean±SD (range). n – Number of sites treated; GRD – Gingival recession depth; PD – Probing depth; CAL – Clinical attachment level; KTW – Keratinized tissue width; SD – Standard deviation; mm – Millimeter; P – P-value

Table 2

Comparison of percentage root coverage and percentage complete root coverage in Group I and Group II

Time (months)	Group I	Group II	P
Percentage MRC (in mm)
3	79.49±21.83	80.15±19.65	0.8170
6	93.17±13.23	95.68±10.13	0.2925
Percentage CRC (in mm)
3	42.66	50.66	0.326
6	78.66	82.66	0.535

Percentage of mean root coverage presented as mean±SD (range). Statistically nonsignificant (P>0.05). MRC – Mean root coverage; CRC – Complete root coverage; SD – Standard deviation; P – P-value

CRC was accomplished in 32 out of 75 (42.66%) in Group I and 38 out of 75 (50.66%) treated sites in Group II at 3 months, whereas it was achieved in 59 out of 75 (78.66%) treated sites in Group I and 62 out of 75 (82.66%) treated sites in Group II at 6 months. Although Group II exhibited more sites with CRC than Group I, the difference was nonsignificant statistically [Table 2].

CBCT assessment showed an increase in mean GMB in Group II as against Group I at 6 months. Marked increase of GT in Group II in comparison with Group I at 6 months [Table 3]. Root coverage esthetic score and Visual Analog Scale (VAS) in both the groups were recorded [Table 4].

Table 3

Comparison of cone-beam computed tomography parameters in Group I and Group II (n=75)

	Mean±SD (mm)		P
	Group I	Group II
GMB (mm)
Baseline	2.36±0.55	2.47±0.56	0.2268
6 months	3.58±0.51	3.77±0.46	0.2554
GT1 (mm)
Baseline	1.15±0.56	1.06±0.31	0.2253
6 months	1.85±0.53	2.30±0.61	<0.001#
GT2 (mm)
Baseline	1.47±0.45	1.29±0.35	0.2262
6 months	2.02±0.36	2.44±0.61	<0.001#
GT3 (mm)
Baseline	1.11±0.36	1.10±0.35	0.8633
6 months	1.73±0.39	2.23±0.65	<0.001#

#Statistically highly significant (P<0.001). n – Number of sites treated; mm – Millimeter; GMB – Bone crest to gingival margin; GT – Gingival thickness; SD – Standard deviation; P – P-value

Table 4

Distribution of root coverage esthetic score and visual analog scale in Group I and Group II

Variable	Group I	Group II	P
RES	8.69±1.46	8.84±1.41	0.5332
VAS-P	70.0±29.91	65.0±28.56	0.5581
VAS-E	72.5±25.52	75.0±25.64	0.7546

All values presented as mean±SD (range). Statistically nonsignificant (P>0.05). RES – Root coverage esthetic score; VAS – Visual analog scale; VAS-P – VAS pain; VAS-E – VAS esthetic; P – P-value

DISCUSSION

The results of our split-mouth randomized controlled trial in CAFB group are similar with the previously reported studies, but we obtained more MRC,[67] probably due to the differences in morphology of the defects treated and the treatment protocol.

Postoperative position of marginal relative to CEJ is essential for achieving CRC.[5] The suspending sutures around the bonded orthodontic buttons provide an anchorage for stabilizing the flap coronally, during first 2 weeks of crucial wound healing period.[28] The significant reduction in recession depth and higher percent root coverage, 6 months from baseline could be due to this modified suturing technique. The technique involves a split-full-split thickness flap design which enables greater mobilization of the flap. It provides a better opportunity for root coverage by elevating a full-thickness mucoperiosteal flap apical to the recession defect thus preserving the maximum keratinized tissue, reducing the chances of flap perforation. The surgical papillae created by this technique gives better esthetics.

A positive relationship between baseline measurements of GT and treatment type and outcome was observed and areas with thick biotype (>0.8 mm) exhibited clinical outcomes with better final esthetics.[29] In our study, the treatment sites had thick periodontal biotype (≥1.06 mm) which could be the reason for obtaining good MRC even in CAFB group.

We observed more MRC and CRC at 3 and 6 months in Group II as against Group I which showed advantage of use of PRF along with CAFB, similar to the previous studies.[2530] However, no statistically significant difference was seen in GRD, MRC, and CRC between both the groups.

Contrary to our findings, Aroca et al. observed significant increase in measurements of MRC and CRC in CAF alone as compared to CAF + PRF membrane group at 6 months.[31] They stored PRF membrane at 4°C until surgery, which can affect platelet morphology. Studies have demonstrated that exposure of platelet to cold temperatures compromises their in vivo survival. Choukroun et al.[32] advised PRF administration at surgical site soonest possible for optimal success of the treatment and same method was used in our study.

In our study, we observed a significant increase in the KTW over the period of 6 month in both the groups, due to an inherent tendency of mucogingival line to gain back its originally decided position. The coronal improvement of the marginal gingiva level was attributed to creeping attachment effect over time and might be obtained by thick gingival tissue achieved after positioning of PRF membrane.[33]

Growth factors liberated from platelets and leukocytes within the PRF stimulate angiogenesis through fibroblast growth factor and vascular endothelial growth factor.[34] PRF also acts as a fibrin glue to stabilize the flap. It has the property of reduced necrosis and shrinkage of the flap and contains thrombin which polymerizes fibrinogen into fibrin that favors wound healing.[35]

Owing to the high predictability of CAF combined with CTG, many authors compared the efficacy of PRF membrane with CTG.[223637] Therefore, it is advised that for treatment of multiple recession defects PRF membrane may be an effective alternative means without requirement of additional surgery. The significant differences were not obtained for GRD reduction, but for the GT of tissue obtained in CAFB + PRF group.

There are however a few limitations of this study in terms of a smaller sample size which may have resulted in insignificant difference between groups with regard to percentage root coverage and separate results for Miller's Class I and Class II gingival recession defects were not measured.

CONCLUSIONS

Findings of this study indicate that CAFB + PRF membrane can contribute beneficial effects in achieving better results with respect to of GRD reduction, MRC, increased KTW, and GT. These parameters ultimately lead to an enhanced gingival esthetics, which is an important result in root coverage procedures. However, additional clinical trials with longer observation period are desirable.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.