Keywords cell proliferation - gingiva - hyaluronic acid - open gingival embrasure - platelet-rich
fibrin - regeneration
Introduction
Inadequate interdental papillae are a challenge in modern dentistry. This condition
impacts the function and esthetics of natural teeth, restorations, and implants. Losing
interdental papillae increases the risk of periodontal disease and implant failure,
as the resulting gaps can accumulate plaque and food debris. Clinically, interdental
papillae loss can occur singly or in multiples with various etiologic factors. The
prevalence of interdental papillae loss in adults is 38%, based on a study of 119
cases, while in adolescents, the prevalence is 41.9% based on 129 cases. A loss of
papillary height of 2 mm poses a significant issue in orthodontics. Both dentists
and patients generally agree that a noticeable loss of 3 mm in tooth structure is
less esthetically pleasing. Achieving harmony between hard and soft tissues is essential
for stabilizing teeth and preventing plaque-related diseases, such as dental caries
and periodontal disease.[1 ]
Papillae reconstruction is a complex treatment procedure that requires careful case
selection and appropriate techniques and materials. The main goal of papillae reconstruction
is to surgically or nonsurgically modify the gingival biotype. The gold standard for
rebuilding papillae is surgical intervention combined with a gingival connective tissue
graft. However, this method can lead to discomfort for the patient, as it creates
a second surgical site at the donor location.[2 ]
In addition to surgical procedures, papillae reconstruction procedures can be performed
nonsurgically. A systematic review and meta-analysis showed that hyaluronic acid (HA)
injection can be an efficient nonsurgical treatment for narrow interdental papillae
loss[3 ] despite the low success rate of surgical procedures.[4 ] Nonanimal stabilized HA dermal fillers are currently accessible and have been approved
for tissue regeneration by the Food and Drug Administration in more than 60 countries,
including Indonesia. However, the clinical effectiveness of HA postinjection treatment
results is inconsistent, with side effects such as pain, intermittent edema, erythema,[5 ] and a burning sensation after the injection.[6 ] These HA allergic reactions can be treated with injectable platelet-rich fibrin
(PRF).[7 ] However, the quantity of injectable PRF is limited. Further research is required
to optimize the use of PRF, particularly for multiple black triangle therapy.
Leukocyte PRF (L-PRF) effectively repairs the loss of interdental papilla.[8 ] The conventional process for preparing L-PRF is relatively simple. A fixed-angle
centrifuge spins human blood at 2,700 rpm for 12 minutes. The subsequent fibrin clot
is sliced and compacted to form a dense, robust L-PRF membrane.[9 ] This membrane is applied using a variety of surgical procedures and has been shown
to totally or partially repair the papillae while improving patient comfort.[8 ]
Fibrin clot compression produces by-products, such as L-PRF exudate and buffy coat.
Unfortunately, these by-products are often discarded, even though the exudate still
contains valuable growth factors,[10 ] and the buffy coat that was known as concentrated PRF (C-PRF) is more affluent in
platelets and leukocytes than injectable PRF,[11 ] which is essential for regeneration. The effects of injecting the L-PRF by-product
layer into interdental papillae have yet to be studied, either in vivo or clinically. This study aims to compare the regenerative effects of various types
of L-PRF by-products (including L-PRF exudate, C-PRF, and a combination of C-PRF and
L-PRF) with HA as a nonsurgical treatment for the reconstruction of interdental papillae.
The regeneration parameters were evaluated clinically, histologically, and immunohistochemically.
Materials and Methods
PRF Preparation and Cell Count
The research protocol has been approved by the Research Ethics Commission of the Faculty
of Dentistry at Gadjah Mada University under the number 8/UN1/KEP/FKG-RSGM/EC/2023.
PRF was derived from healthy, nonsmoking individuals with a normal platelet count
ranging from 150,000 to 450,000 cells/µL in their blood who were not taking any medications
that could influence platelet function.
After signing the consent form, up to 10 mL of venous blood was drawn and placed in
a glass tube without anticoagulants. The blood was centrifuged for 12 minutes at 2,700 rpm
in a fixed-angle centrifuge.[9 ] Following centrifugation, the samples were allowed to stand for ∼3 minutes. This
study separated the PRF based on the layer produced using scissors and then stored
it in a labeled container.
The fibrin clot's middle layer was compressed using a PRF box, resulting in a liquid
by-product called L-PRF exudate. The layer above the red blood cell layer is called
the buffy coat, or C-PRF, while the layer between the fibrin and the buffy coat comprises
a combination of L-PRF and C-PRF. The number of platelets and leukocytes was counted
in each layer to ensure that the centrifugation procedure in this study can separate
the PRF layer as effectively as in previous research.[11 ]
In vivo Study on Modified Open Gingival Embrasure Model and Data Analysis
This in vivo study employed a modified open gingival embrasure (OGE) model, as shown in [Fig. 1 ]. The sample size was determined using the formula E = N − T.[12 ] Based on this formula, the sample consists of 15 rats divided into five groups:
L-PRF exudate (n = 3), C-PRF (n = 3), a combination of L-PRF exudate and C-PRF (n = 3), HA (n = 3) as treatment groups, and phosphate-buffered saline (PBS) (n = 3) as the control group.
Fig. 1 Research flow of in vivo study on modified OGE model. The space of mandibular incisors is more expansive after
lateral force to confirm OGE. C-PRF, concentrated platelet-rich fibrin; HA, hyaluronic
acid; L-PRF, leucocyte platelet-rich fibrin; OGE, open gingival embrasure; PBS, phosphate-buffered
saline.
Sprague-Dawley male rats weighing between 250 and 300 g were kept in a breeding room
with a 12-hour light/dark cycle at 25°C and a humidity level ranging from 64 to 80°F.
During both the maintenance and treatment periods, the animals were provided with
a standard pelleted diet and ad libitum access to tap water. Before treatment, the
animals were anesthetized intramuscularly with ketamine hydrochloride (Ketamil; Ilium,
Troylab, Australia) at a dosage of 90 mg/kg of body weight and xylazine (Xyla, Interchemie,
The Netherlands) at a dosage of 10 mg/kg of body weight.[13 ]
This study modified the OGE model described in the previous study.[13 ]
[14 ] Unlike the previous study, this study induces the OGE using a U-shaped 20-mm-long,
0.016-gauge stainless steel wire looped onto the mandibular incisors and secured with
flowable composite resin. This wire was applied to produce lateral pressure and cause
space between the mandibular incisor (OGE width). On day 7 postinduction, clinical
parameters, which are OGE width and spring papilla distance (SPD), were measured using
a sliding caliper. Following OGE confirmation, 20 µL of various test materials were
injected 2 mm from the apex of the interdental papillae using a 30G syringe.
On day 14, the animals were euthanized, and the interdental papillae tissues between
the mandibular incisors were processed. The papillae height (SPD), histological (fibroblast,
blood vessels, collagen density, and epithelial thickness), and immunohistochemical
(proliferating cell nuclear antigen [PCNA] expression) parameters were used to determine
interdental papillae regeneration. The SPD on day 7 was analyzed statistically using
a one-way analysis of variance (ANOVA). The Kruskal–Wallis' test was used to analyze
the OGE width on days 7 and 14, and the SPD on day 14, which were not normally distributed.
The least significant level is less than 0.05.
Histological Study and Data Analysis
The number of fibroblasts, blood vessels, collagen density, and epithelial thickness
were assessed through histological examinations. Paraffin blocks were cut into slices
of 3-µm thickness and stained with Masson's Trichrome Goldner (Bio-Optica, Milano,
Italy). In a double-blind study, observations were conducted by two reliable independent
observers. Each preparation was evaluated in five fields of view at ×400 magnification
using an Optilab camera and ImageJ software. The histological data were normally distributed
and were analyzed statistically using a one-way ANOVA. Tukey's honestly significant
difference (HSD) test was employed to compare the differences between the two groups.
A significance level of less than 0.05 indicated a statistically significant difference.
Immunohistochemical Study and Data Analysis
To perform immunohistochemistry, a 3-µm-thick paraffin block is cut and dried at 37°C
before being heated in a heater at 60°C for 30 to 60 minutes. The tissue preparations
were performed, and the PCNA primary antibody was applied based on the instructions.
Two reliable, independent observers (reliability value >80%) counted the number of
brown cell nuclei in a double-blind method to detect positive PCNA expression.[14 ] All samples were evaluated in five fields of view at ×400 magnification using an
Optilab camera and Image J software. The immunohistochemical data followed a normal
distribution and were analyzed statistically using a one-way ANOVA. Tukey's HSD test
was used to compare the differences between the two groups. A significance level of
less than 0.05 indicated a statistically significant difference.
Results
Cell Counts of L-PRF Layer
The standard procedure for preparing L-PRF resulted in four distinct layers above
the layer of red blood cells. Test findings indicated that the C-PRF layer contains
the highest concentration of platelets and leukocytes. Additionally, the combination
of C-PRF and L-PRF exudate had more platelets and leukocytes than the L-PRF exudate
layer alone. In contrast, the platelet-poor plasma layer lacked platelets and leukocytes
([Table 1 ]).
Table 1
Platelet and leucocyte count of PRF layers
PRF layer
Number of cells (109 )
Platelet
Leucocyte
PPP
0
0
L-PRF exudate
17
0.3
C-PRF + L-PRF exudate
32
3.9
C-PRF
44
9.1
Abbreviations: C-PRF, concentrated platelet-rich fibrin; L-PRF, leucocyte platelet-rich
fibrin; PPP, platelet-poor plasma.
Width of OGE
On day 0 following the OGE induction, the wire was positioned parallel to the gingival
margin, but a gap developed shortly after the wire was activated. By day 7 postinduction,
the interdental gap had widened, and the position of the wire had moved more coronally.
Notably, no pus or redness was observed on the interdental papillae. [Table 2 ] indicates that the width of the interdental space in all groups on day 7 (p -value = 0.105) and day 14 (p -value = 0.137) did not show any significant differences (p -value > 0.05).
Table 2
Comparison of clinical parameters in the modified OGE model
Parameter
Group
Descriptive
p -Value
OGE width on day 7
L-PRF exudate
1.3 (1.3–1.38)
0.105
C-PRF + L-PRF exudate
1.14 (1.1–1.2)
C-PRF
1.2 (1.14–1.3)
HA
1.3 (1.1–1.32)
PBS
1.32 (1.3–1.78)
OGE width on day 14
L-PRF exudate
1.58 (1.4–1.62)
0.137
C-PRF + L-PRF exudate
1.2 (1.2–1.4)
C-PRF
1.4 (1.2–1.7)
HA
1.32 (1.2–1.38)
PBS
1.54 (1.38–1.72)
SPD on day 7
L-PRF exudate
1.47 ± 0.35
0.422
C-PRF + L-PRF exudate
1.61 ± 0.45
C-PRF
1.71 ± 0.50
HA
1.34 ± 0.55
PBS
2.13 ± 0.68
SPD on day 14
L-PRF exudate
2.12 (2.10–2.54)
0.255
C-PRF + L-PRF exudate
2.36 (2.16–2.80)
C-PRF
2.2 (2.19–2.80)
HA
2.42 (2.4–2.84)
PBS
2.74 (2.66–2.84)
Abbreviations: C-PRF, concentrated platelet-rich fibrin; HA, hyaluronic acid; L-PRF,
leucocyte platelet-rich fibrin; OGE, open gingival embrasure; PBS, phosphate-buffered
saline; SPD, spring papilla distance.
Height of Interdental Papillae
The height of the interdental papillae was measured as the distance between the wire
and the tip of the papillae (referred to as SPD). [Table 2 ] indicates no significant differences in the height of interdental papillae across
all groups on day 7 (p -value = 0.422) and day 14 (p -value = 0.255).
Histological and Immunohistochemical Parameters
The ANOVA test displays significant differences in various parameters: the number
of fibroblast cells (p -value = 0.000), the number of blood vessels (p -value = 0.000), collagen density (p -value = 0.003), epithelial thickness (p -value = 0.045), and PCNA expression (p -value = 0.017), among the test groups. The histological parameters are shown in [Fig. 2 ], and Tukey's HSD test in [Fig. 3 ]. Significant differences between the two groups were observed at a p -value of less than 0.05.
Fig. 2 Comparison of histological parameters with Masson's Trichrome Goldner staining in
studied groups. C-PRF, concentrated platelet-rich fibrin; HA, hyaluronic acid; L-PRF,
leucocyte platelet-rich fibrin; PBS, phosphate-buffered saline.
Fig. 3 Comparison of histological and immunohistochemical parameters of interdental papillae
regeneration in studied groups. The significance of a difference (*) is indicated
when the p-value is less than 0.05. C-PRF, concentrated platelet-rich fibrin; HA,
hyaluronic acid; L-PRF, leucocyte platelet-rich fibrin; PBS, phosphate-buffered saline.
All types of PRF demonstrate a higher number of fibroblasts compared with PBS and
HA. L-PRF exudate contains significantly more fibroblasts than PBS (p -value = 0.001) and HA (p -value = 0.003). Similarly, C-PRF shows a higher fibroblast count than PBS (p -value = 0.002) and HA (p -value = 0.005). Furthermore, the combination of L-PRF exudate and C-PRF exhibits
a more significant fibroblast number than PBS (p -value = 0.001) and HA (p -value = 0.002). However, there are no significant differences in fibroblast counts
between L-PRF exudate and C-PRF (p -value = 0.993), nor between the combination of both PRF types and the C-PRF group
(p -value = 0.971).
All types of PRF demonstrate a denser collagen structure compared with PBS. L-PRF
exudate contains significantly denser collagen than PBS, with a p -value of 0.018. Similarly, C-PRF shows greater collagen density than PBS, with a
p -value of 0.003. Additionally, the combination of L-PRF exudate and C-PRF exhibits
denser collagen than PBS, yielding a p -value of 0.022. However, there are no significant differences in collagen density
between L-PRF exudate and HA (p -value = 0.995), C-PRF and HA (p -value = 0.893), or between the combination of both types of PRF and HA (p -value = 0.984).
The C-PRF group exhibited a higher number of blood vessels compared with the PBS group
(p -value = 0), the HA group (p -value = 0.004), the L-PRF exudate group (p -value = 0.002), and a combination of both types of PRF (p -value = 0.004). No significant differences were observed among the other groups (p -value > 0.05).
The C-PRF had a thicker epithelial width than the PBS, with a p -value of 0.036. However, no significant differences were observed when comparing
C-PRF to the HA group (p -value = 0.848), the L-PRF exudate (p -value = 0.171), or a combination of both types of PRF (p -value = 0.355). No significant differences were found among the other groups, as
indicated by a p -value greater than 0.05.
This study showed that the expression of PCNA in the C-PRF group was significantly
higher compared with the PBS group (p -value = 0.014) and the L-PRF exudate (p -value = 0.041). However, there was no significant difference between the C-PRF group
and the HA group (p -value = 0.235) or between the C-PRF group and the combination of both PRFs (p -value = 0.427). Furthermore, the L-PRF exudate showed no significant differences
from the HA group (p -value = 0.775). Similarly, the combination of both PRFs also displayed no significant
difference compared with the HA group (p -value = 0.989).
Discussion
Papilla reconstruction procedures can be performed nonsurgically by injecting material
to enhance the gingival biotype. In this study, the injected PRF is a by-product of
the L-PRF membrane preparation. Specifically, these include L-PRF exudate, C-PRF,
and a combination of L-PRF exudate and C-PRF. This investigation focused on separating
the layers formed during the preparation, while a previous study examined the layers
formed per 1 mL of material.[11 ] By adjusting the separation process, this study achieved consistent results that
align with previous findings.
[Table 1 ] shows that the buffy coat layer, or C-PRF, contained the highest concentrations
of platelets and leukocytes, whereas the L-PRF exudate group exhibited the lowest
cell counts. In this study, we separate the PRF based on the layer produced. Unlike
the previous study, which separated the layer per milliliter,[11 ] this procedure is advantageous because it is simple and easy to implement in clinical
settings.
The regeneration process was assessed using a wire-induced OGE animal model. This
model is deemed optimal, as it can replicate clinical conditions while allowing for
examination of morphological and histological changes in the interdental papillae.[15 ] The measurements of the OGE space observed in all test groups did not differ significantly
after induction (day 7) or injection (day 14). It showed that the width of the interdental
papillae stayed consistent across the various test groups, allowing for effective
management of individual animal variability. Controlling the individual variety of
OGE space is important as this factor may influence the height of the interdental
papillae.
In this study, injecting L-PRF, C-PRF exudates, or a mixture of the two forms of PRF
increased interdental papillae fibroblast proliferation more than PBS. PRF is a biological
material derived from a patient's blood and is rich in growth factors. PRF promotes
the expression of key growth factors for gingival fibroblasts, including transforming
growth factor beta (TGF-β), vascular endothelial growth factor (VEGF), bone morphogenetic
protein 2,[16 ] and fibroblast growth factor.[17 ]
Human L-PRF exudate fluid enhances the number of fibroblasts within 3 days of injection.[10 ] It contains platelet-derived growth factor (PDGF) and TGF-β, which promote fibroblast
cell proliferation and migration.[18 ] C-PRF increases the production of PDGF and TGF-β while also stimulating proliferation
and migration activities.[19 ] However, the study found no significant difference (p > 0.05) in the number of fibroblast cells after injecting L-PRF exudate, C-PRF, and
combining both PRFs. This lack of difference may be influenced by individual variations
related to platelet counts and the time interval between blood collection and centrifugation.
Further research is needed to explore the differences in growth factors among the
various PRF layer groups and how they affect the proliferation of gingival interdental
papillae fibroblasts.
The number of fibroblasts in the PRF groups was higher than that in the HA group.
After the HA injection, the number of fibroblasts was similar to that observed in
the PBS group. This result contradicts previous research that suggested HA injection
can enhance the presence of gingival fibroblasts.[20 ] Several factors may have influenced this outcome, including the type of HA used,
its concentration, the injection technique, and the body's cellular response.[21 ]
The collagen density in the PRF group was higher than that in the PBS group. This
suggests that the PRF group plays a significant role in forming the extracellular
matrix during the regeneration of the interdental papilla. This finding aligns with
previous studies indicating that PRF enhances collagen formation in periodontal tissues.[20 ] Additionally, PDGF and TGF-β stimulate the proliferation and migration of fibroblasts
and collagen.[22 ]
The collagen density after PRF group injection did not differ significantly ([Fig. 1 ]). This finding suggests that all forms of liquid PRF used in this study have similar
potential to enhance collagen density despite variations in the cell's composition
of liquid PRF. Furthermore, the increased platelet count observed in C-PRF did not
impact collagen density at day 7. Notably, C-PRF, derived from human blood, gradually
releases its growth factor content over 10 days, with only a portion being released
by day 7 postinjection.[23 ]
It was also observed that C-PRF stimulates the production of type 1 collagen within
the first 10 days of using the test material. However, the limited observation period
of just 7 days in this OGE animal model poses challenges due to the physiological
movement associated with the eruption of mandibular incisor teeth.[15 ] Therefore, developing an animal model that allows for long-term studies of collagen
density is essential.
HA injection resulted in fewer fibroblasts than PRF; however, collagen density remained
consistent across all forms of PRF. This implies that although their mechanisms differ,
both materials can stimulate collagen fiber production equally. In the early stages
of wound healing, HA does not promote fibroblast cell proliferation but influences
collagen maturation and the remodeling of the extracellular matrix.[24 ]
Several mechanisms contribute to these effects, including HA's interaction with cell
surface receptors. This interaction activates signaling pathways that enhance fibroblast
activity and collagen formation.[25 ] Additionally, HA may promote chondrocyte activity and activate mechanotransduction
pathways, enabling cells to respond more effectively to mechanical stimuli within
the extracellular matrix.[26 ]
HA has been shown to stimulate collagen synthesis in the gingival area in experimental
OGE models.[15 ] Clinically, HA injection has been demonstrated to improve the height of interdental
papillae in cases of classes I and II papillae loss.[27 ] However, this treatment can also lead to swelling, discomfort, and a burning sensation
at the injection site.[5 ] The therapeutic application of HA in clinical practice remains uncertain due to
issues concerning predictability, long-term effects, and the stability of HA in tissues.
Rebuilding interdental papillae presents a challenge due to the narrow and delicate
area and the limited number of blood vessels.[28 ] In this study, the number of blood vessels significantly increased following the
injection of C-PRF compared with the PBS group, suggesting that C-PRF is more effective
in promoting vascularization. It is crucial for supplying oxygen and nutrients during
the regeneration process.[29 ]
C-PRF boasts platelet concentrations more than 1,500% higher than standard levels.[19 ] Centrifugation activates platelets, which release growth factors such as PDGF, TGF-β1,
endothelial growth factor, and VEGF from their α granules.[30 ] Additionally, C-PRF contained a higher concentration of leukocytes than both L-PRF
and C-PRF exudates, further enhancing its potential benefits.
The injection of C-PRF resulted in a significantly greater number of blood vessels
compared with HA. The number of blood vessels following HA injection was similar to
that observed in the PBS group. It indicates that only C-PRF can enhance vascularization
7 days after injection, while HA administration does not affect vascularization.
Previous studies on the impact of HA on vascularization have produced conflicting
results. Although HA can promote angiogenesis, its effectiveness is largely influenced
by its molecular size and cross-linking properties.[31 ] High-molecular-weight HA is known for its anti-inflammatory characteristics, suppressing
the body's immune response, supporting tissue healing,[32 ] and inhibiting angiogenesis while ensuring blood vessel stability.[33 ] Conversely, HA with a molecular weight of less than 200 kDa can trigger inflammation
and angiogenesis by interacting with specific receptors and the receptor for hyaluronan-mediated
apoptosis (RHAMM). Additionally, HA attracts stromal cells, fostering cell proliferation
and migration.[34 ]
This study found that C-PRF stimulated vascularization more effectively than other
PRF groups. C-PRF contained a higher concentration of platelets and leukocytes compared
with L-PRF exudates. While L-PRF exudates have platelets and leukocytes, their concentrations
are lower than those in the L-PRF membrane: 6% platelets and 0.9% leukocytes.[35 ]
Additionally, there were differences in the release of growth factors between the
two types of PRF. C-PRF releases growth factors steadily starting on day 3 and continuing
beyond that,[10 ] whereas L-PRF exudates exhibit significant growth factor release on day 3 but in
smaller amount than L-PRF membranes.[36 ] The difference in growth factor release might influence gingival regeneration, as
the growth factor induces a complex series of cellular and molecular events essential
for cell proliferation. Further studies are needed to explore the variations in growth
factor release among L-PRF, C-PRF, and L-PRF exudates over time.
Loss of interdental papillae can increase the risk of inflammation in periodontal
tissues. The epithelium is crucial in defending periodontal tissue as a barrier against
microbial invasion.[37 ] Unlike previous studies on wound healing, this study observed epithelialization
occurring in the uninjured area of the papilla apex. [Fig. 1 ] shows that C-PRF injection increased epithelial thickness and PCNA expression at
the papilla apex compared with PBS treatment. This suggests that C-PRF may stimulate
the proliferation of epithelial cells, thereby enhancing the thickness of the epithelial
layer in interdental papillae.
These findings align with earlier research indicating a relationship between PCNA
expression and localization in epithelial cells[38 ] and fibroblasts.[25 ] Platelet growth factors, such as EGF, have been shown to influence epithelial proliferation
as active signaling molecules.[39 ] Additionally, the bioactive components of PRF regulate fibroblast proliferation
and collagen production, fostering epithelial cell regeneration.[40 ]
The height of the interdental papillae was not significantly different across all
test groups. It suggests that the injection of the test material does not influence
the clinical morphology, particularly the increase in the height of the interdental
papillae observed on day 7 postinjection.[15 ]
In the present study, the wire was positioned parallel to the apex of the papillae
during the induction of OGE. However, after the induction, it appeared to have migrated
more incisively. The physiological process of vertical tooth eruption can shift the
observation point. Another potential contributing factor is the lateral mechanical
movement observed in the OGE model. This movement promotes lateral rather than coronal
regeneration as the body responds to the resulting damage or lesion.
Rat animal models have been widely used to observe short-term interdental papillae
regeneration.[15 ] This study observed regeneration parameters on day 14, the seventh day following
injection. This represents the peak of cell proliferation. However, the regeneration
of interdental papillae is about immediate improvements and the sustainability of
the results. Regrettably, this animal study could not be observed for an extended
period due to the limitations of this animal model. This animal could not fully replicate
the human condition because tight tooth contact was lost afterward when papillary
augmentation was attempted, and only the short-term effects were validated due to
the natural eruption of the incisors.[15 ] An appropriate experimental animal model is necessary to evaluate the effects of
the test substance administration over an extended period.
The results of this study indicate that PRF by-products can enhance fibroblast proliferation
and increase collagen density. Additionally, C-PRF offers better vascularization than
HA. Despite this study's limitations, the findings are expected to provide valuable
insights for optimizing the use of L-PRF in restoring interdental papillae, particularly
in cases of multiple papilla loss. PRF membranes can be applied surgically in clinical
settings, while the by-products generated during their preparation can also be utilized
for nonsurgical purposes.
Some clinical studies showed that the injectable PRF was applied several times and
observed longer to achieve the reconstruction effect. Clinical trials, especially
longitudinal studies that monitor patients over extended periods, can assess the stability
of interdental papillae height and esthetic outcome.
Conclusion
This study found that the by-products of L-PRF membrane preparation—specifically,
L-PRF exudate, C-PRF, and a mixture of the two—significantly increased the proliferation
of gingival fibroblasts in the interdental papillae compared with HA. Among these,
only C-PRF could promote vascularization in the interdental papillae while also stimulating
epithelial proliferation, leading to an increase in epithelial thickness at the apex
of the interdental papillae.
However, the observed cellular and molecular changes peaked on day 7 postinjection
and did not result in alterations to collagen density or the height of the interdental
papillae. To determine the clinical significance of these findings, a more comprehensive
clinical trial with a longer observation period is needed to evaluate the potential
of L-PRF as a nonsurgical therapy for reconstructing interdental papilla.
