A novel injectable platelet-rich fibrin reinforced papilla reconstruction technique.

Formation of black triangles due to the loss of interdental papilla is one of the utmost perplexing esthetic problems of the periodontium. Many surgical and nonsurgical treatment options have been researched upon to obtain complete papillary fill, but minimally invasive procedures have always been the choice of treatment both for the operator as well as the patient. This article describes the use of injectable platelet-rich fibrin (i-PRF) as a novel nonsurgical technique for the reconstruction of deficient interdental papilla. This is probably the first article that describes the use of i-PRF for the nonsurgical treatment of black triangles. Six sites with the presence of deficient interdental papilla in four patients were selected for this case series. After completion and reevaluation of scaling and root planing, autologous i-PRF was injected at the base of the interdental papilla using the insulin syringe. Photographs obtained before the treatment and at 1, 3, and 6 months after the intervention were assessed by Image J software along with clinical measurements. The use of novel nonsurgical injectable PRF technique allows clinician to successfully treat deficient interdental papilla. Copyright:

INTRODUCTION

Existence and preservance of interdental papilla is one of the important points of concern in esthetic dentistry.[1] Loss of interdental papilla may lead to the formation of unappealing dark triangles, resulting in food impaction and plaque buildup. This soft tissue is delicate and fragile; is susceptible to inflammation leading to recession, bone loss or both and cannot be predictably filled when recessed, due to its low blood supply.[23]

Reconstruction of the interdental papilla in the esthetic region is challenging.[4] For reconstruction of deficient interdental papilla, several surgical procedures have been advocated. However, these methods are usually invasive and unpredictable.[56] Nonsurgical management using hyaluronic acid (HA) has been attempted in several studies and though the product is biocompatible and given good results with promising levels of patient's satisfaction, it may require repeated administration of injections and also requires some expense.[789]

Hence, a novel minimally invasive autologous approach known as the injectable- platelet-rich fibrin (i-PRF) reinforced papilla reconstruction technique (i-PRT) is proposed. The purpose of this article is to evaluate clinically, the efficacy of the new i-PRT in the treatment of black triangles.

CASE REPORT

Four patients with a chief complaint of poor esthetics and formation of unappealing black triangles in the anterior sextant were carefully chosen for the “i-PRF reinforced PRT” at the department of periodontology of the institute during March to May 2019. Patients having well-aligned maxillary teeth, no caries, no proximal restorations, fixed prosthesis or any orthodontic appliances with the presence of at least one class I or II interdental papilla loss in maxillary or mandibular anterior region,[10] <7 mm of distance between the contact point (CP) and inter-proximal bone crest and <4 mm of probing depth at the selected sites, plaque index,[11] and gingival index[12] scores <1 were selected for the study.

Case management

All the study participants were well-versed about the treatment protocol, and informed written consent was obtained. Ethical clearance was obtained from the Ethical Committee of the Institute before the initiation of the study. All the selected patients underwent full mouth scaling and root planing. At baseline, the following parameters were recorded:

A questionnaire for the assessment of patient's response including questions regarding patient's assessment of black triangle[7] [Table 1]

Table 1

Questionnaire response

Questions	Before treatment				Immediately after treatment				AT 6 months
	Patient 1	Patient 2	Patient 3	Patient 4	Patient 1	Patient 2	Patient 3	Patient 4	Patient 1	Patient 2	Patient 3	Patient 4
How do you feel with the black space showing between your teeth?	C	C	B	C	A	A	A	A	A	B	A	B
					Inference of question 1
A. Not at all noticeable  B. Slightly noticeable  C. Extremely noticeable	C: 3 out of 4 patients (75%) B: 1 out of 4 patients (25%)				A: 4 out of 4 patients (100%)				A: 2 out of 4 patients (50% B: 2 out of 4 patients (50%)
How do you feel witd your smile?	A	B	B	B	C	C	C	C	C	B	C	B
					Inference of question 2
A. Not at all impressive  B. Slightly impressive  C. Extremely impressive	A: 1 Out of 4 patients (25%) B: 3 Out of 4 patients (75%)				C: 4 Out of 4 patients (100%)				B: 2 out of 4 patients (50%) C: 2 out of 4 patients (50%)
Immediately after treatment
Having had this overall experience, would you choose to have the injection procedure again?	Not again: None				Once more: Patient 2				Surely undergo: Patient 1,3,4
					Inference of question 3
	Once more: 1 out of 4 patients (25%) Surely undergo: 3 out of 4 patients (75%)
How painful do you feel the procedure was Score (numeric rating scale) 0,1,2,3,4,5,6,7,8,9,10	Patient 1: 2				Patient 2: 3				Patient 3: 3		Patient 4: 2
					Inference of question 4: Mild pain
Are you still feeling pain or any sensation in the injected area	Yes: None				No: Patient 1,2,3,4
					Inference of question 5
	Response number: 4 out of 4 patients (100%)

Clinical measurement: Distance from the CP to papillary tip (PT) using the prepared stent [Table 2]

Table 2

Measurement using stent

Patient	Sites	Teeth	CP-PT
			Baseline	1 month	3 months	6 months	Papillary fill (%)
1	1	21, 22	4	0	0	0	4 (100)
2	2	11, 21	3	1	1	1	2 (66.6)
3	3	31, 41	3	0	0	0	3 (100)
	4	31, 32	3	0	0	1	2 (66.6)
	5	32, 33	3	0	0	0	3 (100)
4	6	31, 41	4	1	1	1	3 (75)

Percentage papillary fill= CP-PT: Contact point to papillary tip

Photographic measurement: A digital photograph of the selected site was taken by keeping the camera parallel to the required region with the axis of the lens of the camera being parallel/horizontal to the ground. The patient was made to sit in an upright position, looking directly ahead such that the Frankfort plane was parallel to the ground. The obtained photographs were transferred to the image J analysis software. Transferred images were calibrated using the length of the crown measured on the stone cast and the surface area of the lost papilla was measured[78] [Table 3].

Table 3

Photographic analysis (image J analysis)

Patient	Sites	Teeth	Area				Change in surface area (%)
			Baseline	1 month	3 months	6 months
1	1	21, 22	209	0	0	0	100
2	2	11, 21	228	42	46	49	78.5
3	3	31, 41	220	0	0	0	100
	4	31, 32	175	0	0	30	82.8
	5	32, 33	345	0	0	0	100
4	6	31, 41	384	60	74	75	80.4

Percentage change in surface area=

Injectable platelet-rich fibrin procurement

For the preparation of i-PRF, 10 ml of intravenous blood was withdrawn from antecubital region and was centrifuged using plastic tubes (without any additives) in a centrifuge (REMI® Laboratories, India) at 700 rpm for 3 min. Subsequently, the tubes were removed and the top most yellow-orange colored liquid attained was injectable PRF [Figure 1].[131415] Approximately 1 ml of the liquid form of PRF was prepared, using 10 ml of the withdrawn blood.[15] Obtained i-PRF was filled in the insulin syringes and was ready to use at the desired site. i-PRF remains in a liquid state for about 10–15 min, and thereafter, it forms a gel like membrane, because the liquid fibrinogen is converted to solid fibrin, thus, it is important to inject immediately.[1415]

Figure 1

Preparation of injectable platelet rich fibrin (a) Post centrifugation. (b) Collection of liquid injectable platelet rich fibrin from test tube. (c) Injectable platelet rich fibrin collected in insulin syringe

Injection technique

In all the six sites with loss of interdental papilla [Figures 2a and b, 3a and b, 4a, 5a and b], adequate anesthesia was obtained and the needle of the insulin syringe was inserted 2–3 mm apical to the PT directed coronally making an angle of 45° to the long axis of the tooth with its bevel facing apically [Figures 2c, 3c, 4b-d and 5c]. Post injection, the papilla was gently massaged in an incisal direction, for a minute using a gauze piece [Figures 2d, 3d and 5d]. Patients were instructed to use a soft toothbrush coronal to the gingival margin and prevent the use of interdental aids at the treated region. Patients were kept under a 6-month follow-up and observation phase and were recalled for follow up at 1, 3, and 6 months wherein the clinical and photographic parameters were re-recorded [Figures 2e-g, 3e-g, 4e, 5e-g].

Figure 2

(a) Preoperative view showing interdental papillary loss in between 21 and 22. (b) Measurement of distance between contact point to papillary tip using stent and UNC-15 probe. (c) Injectable platelet rich fibrin injected at the base of deficient papilla between 21 and 21. (d) Immediate post injection view. (e) 1 month post injection view. (f) 3 months post injection view. (g) 6 months post injection view

Figure 3

(a) Preoperative view showing interdental papillary loss in between 11 and 21, (b) Measurement of distance between contact point to papillary tip using stent and UNC-15 probe. (c) Injectable platelet rich fibrin injected at the base of deficient papilla between 11 and 21. (d) Immediate post injection view. (e) 1 month post injection view. (f) 3 months post injection view. (g) 6 months post injection view

Figure 4

(a) Preoperative view showing interdental papillary loss in between 41 and 31-33. (b) Injectable platelet rich fibrin injected at the base of deficient papilla between 31 and 41. (c) Injectable platelet rich fibrin injected at the base of deficient papilla between 31 and 32. (d) Injectable platelet rich fibrin injected at the base of deficient papilla between 32 and 33. (e) 6 months post injection view

Figure 5

(a) Preoperative view showing interdental papillary loss in between 31 and 41. (b) Measurement of distance between contact point to papillary tip using stent and UNC-15 probe. (c) Injectable platelet rich fibrin injected at the base of deficient papilla between 31 and 41. (d) Immediate post injection view. (e) 1 month post injection view. (f) 3 months post injection view. (g) 6 months post injection view

Clinical outcome

The assessment of patient's response obtained through the questionnaire revealed that the patients were extremely satisfied with the result obtained [Table 1]. The measurements of the height of the black triangle revealed that there was an appreciable decrease in CP-PT distance and area of the black triangle measurements after 1, 3, and 6 months. On clinical examination, in three sites, 100% papillary fill was observed even after 6 months of injection. In one site, 75% papillary fill was observed, and in two sites, 66.6% papillary fill was observed [Table 2]. The reduction in the surface area of the black triangles, on photographic evaluation also correlated well with the clinical examination [Table 3].

DISCUSSION

The use of noninvasive biocompatible methods such as commercially available HA gel can replace the conventional invasive surgical approaches but requires expense and may require repeated injections.[789] Mansouri et al. in 2013 obtained 50% improvement in 10% of the sites at 3 months and 43% of sites demonstrated improvement in papillary coverage by over 50% at 6 months evaluation using HA for the treatment of black triangles.[8] Mean percentage reduction in surface area of the black triangle treated by HA were 36.5 ± 24.4% and 45.0 ± 28.5% from baseline to 3 months and 6 months, respectively, as reported by Abdelraouf et al. in 2019.[9] Autologous i-PRF is a liquid form of the PRF procured by altering the kind of the centrifugation tube, speed, and time of the centrifugation protocol that was used for PRF preparation. A greater number of platelets, leukocytes, and growth factors are obtained when i-PRF is prepared using low-speed centrifugation concept.[13141617] It takes approximately 10–15 min for liquid i-PRF to clot and transition into a gel, preserving its contents for sustained release in the tissues.[13] It has been stated that i-PRF may hasten healing of wound due to increase in vascularization.[16]

To enhance the concentration of platelets and leukocytes in i-PRF, either the time of centrifugation might be raised from 3 min to 4–8 min[17] and/or a horizontal centrifuge be used than the conventional fixed-angle centrifugation.[18] In order to increase the volume of resultant i-PRF from approximately 1–2 ml, the dimensions of the centrifugation tube be increased from 10 to 13 ml.[19] The resultant i-PRF has been termed as i-PRF + and now-a-days is anticipated to be more suitable for use in esthetic techniques. In the present case series, conventional centrifugation protocol suggested for females was used. A centrifugation time of 4 min has been proposed for males due to greater red cell counts in males as compared to females.[2021] Ozsagir et al. in 2020[22] obtained satisfactory increase in the thickness of gingiva with the use of i-PRF and i-PRF with microneedling. In the present case series, appreciable results were obtained both clinically and photographically in terms of papillary fill. Oswal and Kour[23] found a substantial improvement in the interdental papillary height and gingival thickness over a period of 6 months using free gingival graft and i-PRF.

The measurement of the linear dimension depicts the papillary enhancement, but the exact modification in black space cannot be assessed clinically.[7] Hence, in the present case series, photographic evaluation of the variation in the surface area of the black triangle was also done,[7] and as illustrated by the reduction in CP-PT distance clinically as well as decrease in the surface area of the black triangle photographically, it can be stated that optimal esthetic results and excellent soft tissue fill was obtained with the use of i-PRT. Future short- and long-term researches using a larger sample size should be conducted on this technique to evaluate its effectiveness.

i-PRF is an easy to procure, economical, autologous healing biomaterial and i-PRF reinforced PRT (i-PRT) appears to improve biotype and successfully treat black triangles.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.