Platelet-rich plasma and connective tissue grafts in the treatment of gingival recessions: a histometric study in dogs

The effectiveness of locally injected platelet-rich plasma on orthodontic tooth movement acceleration

OBJECTIVES

To critically appraise the current evidence available from animal studies pertaining to the effectiveness of platelet-rich plasma (PRP) in accelerating orthodontic tooth movement.

MATERIALS AND METHODS

Electronic searches of nine databases were conducted up to June 2020, followed by a hand search of the reference list of eligible studies. The study design required was prospective controlled animal studies. The primary outcome assessed was the rate of orthodontic tooth movement. The secondary outcome evaluated was histological changes after PRP application. Following study retrieval and selection, relevant data were extracted. Risk-of-bias (RoB) assessment was done using the Systematic Review Center for Laboratory Animal Experimentation's Risk of Bias Tool (SYRCLE's Risk of Bias Tool). Two review authors conducted the work of searching, study selection, and quality assessment independently and in duplicate.

RESULTS

Of 193 studies, 5 animal studies were included in this systematic review. Three studies found a positive correlation between PRP injection and tooth movement acceleration, along with corresponding histological changes. Two studies detected no significant difference in tooth movement rate after PRP application.

CONCLUSIONS

Based on the current limited evidence, the efficacy of PRP on tooth movement acceleration remains debatable. More well-designed randomized controlled trials involving humans are called for to obtain more clinically significant conclusions.

Use of Platelet-Rich Fibrin Membranes With Single Implant Placement for Peri-Implant Mucosal Thickness Augmentation: A Case Series Study

INTRODUCTION

The use of platelet-rich fibrin (PRF) membranes has been evaluated for different purposes. However, few studies aimed to assess the effect of PRF membranes on peri-implant mucosal thickness augmentation. Thus, the aim was to evaluate whether the use of PRF membranes placed using the same surgical procedure of single implant installation in the anterior area of the maxilla can result in peri-implant mucosal thickness increase.

CASE SERIES

Eight patients received single maxillary implants (anterior area), covered by three PRF membranes (2,500 rpm/12 minutes, RCFmax = 719.71 g). Clinical parameters (baseline and 3 months postoperative) and patient-centered parameters were evaluated. The buccal peri-implant mucosal thickness (BMT) and ridge defect (RD) parameters showed a statistically significant difference, with a gain of 0.7 ± 0.3 mm in BMT and reduction of 0.8 ± 0.3 mm in RD. Supracrestal tissue height (STH) was >3 mm after 3 months. Postoperative pain and number of analgesics showed low values (0.95 ± 1.06 and 1.92 ± 2.75), respectively, using a visual analog scale (VAS).

CONCLUSION

The use of three PRF membranes along with single implant placement in the anterior maxilla led to an increase in the BMT.

Maxillary sinus lift response to platelet-rich plasma associated with autogenous bone, ceramic biphasic HA/β-TCP (70:30), or deproteinized bovine bone

BACKGROUND

This study evaluated the long-term effects of platelet-rich plasma (PRP) on bone formation and regeneration when associated with autogenous bone graft (AB), porous biphasic calcium phosphate (pBCP), or deproteinized bovine bone (DBB) in maxillary sinus augmentation (MSA) of rabbit.

METHODS

In 54 rabbits, bilateral MSA procedure was performed and randomly one sinus was filled with 200 mm³ material plus blood clot (AB/clot, DBB/clot, and pBCP/clot) and other with the same graft plus PRP (AB/PRP, DBB/PRP, and pBCP/PRP). After 30, 60, and 180 days, microtomographic were performed to analyze the three-dimensional MSA volume and histomorphometric analyses for the percentage of bone and soft tissues ingrowth. Data were compared by two-way ANOVA and the means were compared by the Tukey test, at p < 0.05.

RESULTS

The percentage of pBCP and DBB were nearly unchanged throughout the whole period and bone formation occurred in the spaces between particles. The MSA volume filled with DBB and pBCP agglutinated with clot and PRP maintained constant during all experimental periods (147.2 mm³ and 154.9 mm³, respectively, p = 0.7377), and no significant changes in the new formatted bone and soft tissue were observed between treatments. In AB/clot and AB/PRP, the MSA volume was similar at 30 days (140.3 mm³ and 137.9 mm³, respectively), but a higher and gradual reduction was observed until 180 days. In the AB/PRP, this reduction was significantly higher (44.2%) than AB/clot (22.5%) (p = 0.01792). Histologically, the addition of PRP to AB accelerated the new bone formation/remodeling maintaining the percentage of new bone similar to AB/clot during all experimental volume (p = 0.6406), while the AB particles showed a higher resorption in AB/PRP than AB/clot until 60 days (mean of 7.8% and 15.1%, respectively, p = 0.0396).

CONCLUSION

The association of PRP with the autogenous graft accelerates the process of bone formation/remodeling in MSA, but not had influence on the pBCP and DBB groups.

Experimental and clinical studies on plastic periodontal procedures

We have compiled, in this Periodontology 2000 review, all Latin American literature on experimental and clinical studies of periodontal plastic procedures. The body of literature on this subject has led to a discussion of the features and treatment outcomes of root-coverage procedures. Over time, knowledge on periodontal plastic procedures has become less empirical and more supportive of the clinical management of recession-type defects. Gingival recession etiology, animal studies, free gingival grafts, pedicle flaps (semilunar, laterally positioned, and coronally positioned), and subepithelial connective tissue grafts are extensively reviewed. The use of allografts as an alternative to subepithelial connective tissue grafts, the treatment of multiple gingival recessions, and the rationale for use of guided tissue regeneration and enamel matrix derivative in plastic periodontal procedure is discussed. We also assess how smoking can affect the treatment outcomes in plastic surgery procedures. Minimally invasive procedures are of great value in improving the features of the final tissues. The following aspects identified in this compilation were of great interest: (a) some factors, anatomical in nature, favor the formation of root recessions, but it is the inflammatory process (caused by the presence of biofilm and/or by traumatic toothbrushing) that is responsible for the development of root recessions; and (b) pedicle flap procedures (especially the coronally positioned flap) are extremely versatile and have the most predictable outcome of all root-coverage procedures, especially when combined with subepithelial connective tissue grafting and/or allogeneic grafts. In summary: subepithelial connective tissue grafting is considered as the first option to augment gingival width and thickness, and it may provide better long-term results; the same principles of root-coverage procedures in individual sites appear be used in clinical practice also for multiple-recession type defects; an allograft is an efficient alternative to a subepithelial connective tissue graft and, when it is the treatment option of choice, the use of wide, extended flaps should be considered; because of the superiority of plastic periodontal procedures over guided tissue regeneration and the technical difficulty of the latter, guided tissue regeneration has become obsolete for root-coverage procedures; there is rather a large body of evidence attesting that smoking negatively influences root-coverage procedures, especially subepithelial connective tissue grafts; and minimally invasive techniques may be of great value for improving the results obtained with plastic periodontal procedures, but these techniques need to be better addressed in clinical trials, both in terms of the quality and quantity of the new tissue generated.

An in vitro long-term study of cryopreserved umbilical cord blood-derived platelet-rich plasma containing growth factors-PDGF-BB, TGF-β, and VEGF

PURPOSE

Umbilical cord blood-derived platelet-rich plasma (UCB-PRP) containing growth factors has attracted attention as a biomaterial useful for regenerative medicine. The osteoblastic differentiation of umbilical cord-derived mesenchymal stromal cells (UC-MSCs) can be induced by UCB-PRP.

MATERIALS AND METHODS

Nine samples of UC and UCB were used to conduct an in vitro study that determined the contents of three growth factors (i.e., platelet-derived growth factor, transforming growth factor β-1, and vascular endothelial growth factor) and that examined, by staining with Alizarin red, their ability to induce the osteoblastic differentiation of UC-MSCs at the baseline, 3 months, and 3 years of cryopreservation.

RESULTS

The contents of growth factors in cryopreserved UCB-PRP were markedly elevated compared to those found in UCB at baseline. The samples of UCB that were added with cryopreserved UCB-PRP and those with bone morphogenetic protein-2 were stained granularly with Alizarin red, thus indicating the presence of calcium. The samples of UCB that were not added with UCB-PRP were not stained with Alizarin red. The above-mentioned contents and ability were maintained at 3 years of cryopreservation. Cryopreserved UCB-PRP possibly and advantageously induced the osteoblastic differentiation of UC-MSCs.

CONCLUSION

The potential clinical application of cryopreserved UCB-PRP to regenerative medicine was suggested.

Split-mouth evaluation of connective tissue graft with or without enamel matrix derivative for the treatment of isolated gingival recession defects in dogs

OBJECTIVES

The potential additive effect of an enamel matrix derivative (EMD) to a subepithelial connective tissue graft (CTG) for recession coverage is still controversially discussed. Therefore, the aim of this study was to histologically evaluate the healing of gingival recessions treated with coronally advanced flap (CAF) and CTG with or without EMD in dogs.

MATERIALS AND METHODS

Gingival recession defects (5 mm wide and 7 mm deep) were surgically created on the labial side of bilateral maxillary canines in 7 dogs. After 8 weeks of plaque accumulation and subsequent 2 weeks of chemical plaque control, the 14 chronic defects were randomized to receive either CAF with CTG (CAF/CTG) or CAF with CTG and EMD (CAF/CTG/EMD). The animals were sacrificed 10 weeks after reconstructive surgery for histologic evaluation.

RESULTS

Treatment with CAF/CTG/EMD demonstrated statistically significantly better results in terms of probing pocket depth reduction (P < 0.05) and clinical attachment level gain (P < 0.001). The length of the epithelium was statistically significantly shorter in the CAF/CTG/EMD group than in the CAF/CTG group (1.00 ± 0.75 mm vs. 2.38 ± 1.48 mm, respectively, P < 0.01). Cementum formation was statistically significantly greater in the CAF/CTG/EMD group than following treatment with the CAF/CTG group (3.20 ± 0.89 mm vs. 1.88 ± 1.58 mm, respectively, P < 0.01). The CAF/CTG/EMD group showed statistically significantly greater complete periodontal regeneration (i.e., new cementum, new periodontal ligament, and new bone) than treatment with CAF/CTG (0.54 ± 0.73 mm vs. 0.07 ± 0.27 mm, respectively, P < 0.05).

CONCLUSION

Within their limits, the present findings indicate that the additional use of EMD in conjunction with CAF + CTG favors periodontal regeneration in gingival recession defects.

CLINICAL RELEVANCE

The present findings support the use of EMD combined with CTG and CAF for promoting periodontal regeneration in isolated gingival recession defects.

Biodegradable gelatin/beta-tricalcium phosphate sponges incorporating recombinant human fibroblast growth factor-2 for treatment of recession-type defects: A split-mouth study in dogs

BACKGROUND AND OBJECTIVE

Tissue engineering by using recombinant human (rh) growth factor technology may offer a promising therapeutic approach for treatment of gingival recession. Fibroblast growth factor-2 (FGF-2) has shown the ability to promote periodontal regeneration. Gelatin/beta-tricalcium phosphate (gelatin/β-TCP) sponges have been developed to control the release of growth factors. The present study evaluated the periodontal regenerative efficacy of rhFGF-2 by comparing gelatin/β-TCP sponges incorporated with rhFGF-2 to the scaffolds alone in artificially created recession-type defects in dogs.

MATERIAL AND METHODS

Critically sized buccal gingival recession defects were surgically created on maxillary canine teeth of five dogs. In each animal, defects were randomized to receive either a gelatin/β-TCP sponge soaked with rhFGF-2 (gelatin/β-TCP/rhFGF-2) or phosphate-buffered saline (gelatin/β-TCP). Eight weeks after surgery, biopsy specimens were obtained and subjected to microcomputed tomography and histological analyses.

RESULTS

Complete root coverage was achieved in both groups. Microcomputed tomography revealed significantly greater new bone volume in the gelatin/β-TCP/rhFGF-2 group. Histologically, both groups achieved periodontal regeneration; however, gelatin/β-TCP/rhFGF-2 sites exhibited more tissue regeneration, characterized by significantly larger amounts of new cementum and new bone. Gelatin/β-TCP sites featured increased long junctional epithelium and connective tissue attachment. In the gelatin/β-TCP/rhFGF-2 sites, new bone exhibited many haversian canals and circumferential lamellae as well as remarkably thick periosteum with blood vascularization and hypercellularity.

CONCLUSION

Within the limitations of this study, rhFGF-2 in gelatin/β-TCP sponges exhibits an increased potential to support periodontal wound healing/regeneration in canine recession-type defects.

Healing of localized gingival recessions treated with a coronally advanced flap alone or combined with an enamel matrix derivative and a porcine acellular dermal matrix: a preclinical study

OBJECTIVE

This study aimed to evaluate the effects of a porcine acellular dermal matrix (PADM) with or without an enamel matrix derivative (EMD) on gingival recession defects treated with a coronally advanced flap (CAF) in dogs.

MATERIALS AND METHODS

Miller class II gingival recession defects (5 mm wide and 7 mm deep) were surgically created on the labial side of bilateral maxillary canines in 12 dogs. After 8 weeks of plaque accumulation, the 24 chronic defects were randomly assigned to one of the following 4 treatments: CAF, CAF with PADM (CAF/PADM), CAF with EMD (CAF/EMD), and CAF with EMD and PADM (CAF/EMD/PADM). The animals were sacrificed 10 weeks after surgery for histologic evaluation.

RESULTS

In all groups, root coverage was obtained to a varying degree. PADM was well incorporated in gingival connective tissue in the CAF/PADM and in the CAF/EMD/PADM groups. The height of newly formed bone was significantly greater in the CAF/EMD/PADM group than in the CAF and CAF/PADM groups. New cementum with periodontal ligament-like tissue was predominantly found in the CAF/EMD and CAF/EMD/PADM groups. The CAF/EMD/PADM group showed the greatest amount of new cementum among the groups examined, although the difference was not statistically significant.

CONCLUSION

Within the limitations of the present study, it can be concluded that CAF/EMD/PADM treatment may promote periodontal regeneration in gingival recession defects.

CLINICAL RELEVANCE

The present results suggest that the combination of EMD and PADM in conjunction with CAF may represent a promising approach for treating single Miller class II gingival recessions.

Platelet preparations in dentistry: How? Why? Where? When?

The aim of this article is to review the outcomes of platelet preparations in dentistry. A structured electronic search discovered 348 articles, which described the use of autologous platelet concentrates with a relevance to clinical dentistry. Among these articles, 220 articles investigated platelet rich plasma, 99 investigated platelet rich fibrin, 22 investigated plasma rich in growth factors and 7 investigated the use of concentrated growth factors. Several studies reported beneficial treament outcomes in terms of enhanced bone and soft tissue regeneration.

Platelet-rich plasma, low-level laser therapy, or their combination promotes periodontal regeneration in fenestration defects: a preliminary in vivo study

BACKGROUND

This study histomorphometrically analyzes the influence of platelet-rich plasma (PRP), low-level laser therapy (LLLT), or their combination on the healing of periodontal fenestration defects (PFDs) in rats.

METHODS

PFDs were surgically created in the mandibles of 80 rats. The animals were randomly divided into four groups: 1) C (control) and 2) PRP, defects were filled with blood clot or PRP, respectively; 3) LLLT and 4) PRP/LLLT, defects received laser irradiation, were filled with blood clot or PRP, respectively, and then irradiated again. Animals were euthanized at either 10 or 30 days post-surgery. Percentage of new bone (NB), density of newly formed bone (DNB), new cementum (NC), and extension of remaining defect (ERD) were histomorphometrically evaluated. Data were statistically analyzed (analysis of variance; Tukey test, P <0.05).

RESULTS

At 10 days, group PRP presented ERD significantly lower than group C. At 30 days, group PRP presented NB and DNB significantly greater than group C. Groups LLLT, PRP, and PRP/LLLT showed significant NC formation at 30 days, with collagen fibers inserted obliquely or perpendicularly to the root surface. NC formation was not observed in any group C specimen.

CONCLUSIONS

LLLT, PRP, or their combination all promoted NC formation with a functional periodontal ligament. The combination PRP/LLLT did not show additional positive effects compared to the use of either therapy alone.

Platelet-rich plasma in the treatment of Class II furcation defects: a histometrical study in dogs

Objective

This study was designed to evaluate the potential adjunctive benefits of platelet-rich plasma (PRP) when used with guided-tissue regeneration (GTR) and bioactive glass (BG) in the treatment of Class II furcation lesions.

Material and Methods

Bilateral Class II furcation lesions were surgically created and allowed to become chronic in the mandibular third premolars of 9 dogs. The defects were randomly assigned to: A) GTR+BG and B) GTR+BG+PRP. Similar defects were created in the maxillary third premolars and received the same treatments after 45 days. Dogs were sacrificed 90 days after the first treatment. The histometric parameters evaluated were: connective tissue adaptation, new cementum, new bone, mineralized bone area, non-mineralized bone area, and residual BG particle area.

Results

Data analysis showed a superior length of new cementum and a greater mineralized bone area for group B in both periods (p<0.05). The non-mineralized bone area was greater in the control group (p<0.05) in both periods.

Conclusion

Within the limits of this study, it can be concluded that the use of PRP in the treatment of Class II furcation defects may enhance the amount of new cementum and provide a more mineralized bone in a shorter period of time.

Platelet-rich plasma plus bioactive glass in the treatment of intra-bony defects: a study in dogs

OBJECTIVE

This study was designed to evaluate, histomorphometrically, the association of platelet-rich plasma (PRP) and bioactive glass (BG) in the treatment of periodontal intrabony defects.

MATERIAL AND METHODS

Nine mongrel dogs were included in the study. Three-wall intrabony defects were surgically created at the mesial and distal aspect of first mandibular molar and exposed to plaque accumulation for 1 month. The defects were randomly assigned to the groups: control, BG, PRP, PRP+BG. Dogs were sacrificed 90 days after the surgeries. The histometric parameters evaluated were: length of sulcular and junctional epithelium, connective tissue adaptation, new cementum, new bone, defect extension and area of new bone filling the defect.

RESULTS

A superior area of new bone was observed in PRP+BG and BG (13.80 ± 2.32 mm² and 15.63 ± 2.64 mm², respectively) when compared to the other groups (8.19 ± 1.46 mm² and 8.81 ± 1.47 mm² for control and PRP, respectively). No statistically significant differences were observed in the remaining parameters.

CONCLUSIONS

Within the limits of this study, it may be concluded that PRP failed to provide statistically significant improvements in the histometric parameters.

Mucogingival surgery: where we stand today

Mucogingival problems are developmental and acquired aberrations in the morphology, position, and/or the amount of gingiva surrounding teeth. According to an academic report by American Academy of Periodontology, mucogingival therapy should be advocated for gingival augmentation and to create adequate vestibular depth in areas with insufficient attached gingiva. This paper provides an overview on mucogingival surgical procedures from its inception to the current time.

The effect of platelet-rich plasma on healing of palatal donor site following connective tissue harvesting: a pilot study in dogs

BACKGROUND

Peri-implant plastic surgery includes soft tissue enhancement by connective tissue grafting. The palatal donor site provides peri-implant keratinized mucosa and soft tissue height. Platelet-rich plasma (PRP) contains growth factors that may enhance early healing.

PURPOSE

The present animal study investigated the effect of PRP on wound healing of palatal donor site after connective tissue harvesting.

MATERIALS AND METHODS

In 12 mongrel dogs, bilateral palatal connective tissues of 10 × 15 mm were harvested. At test site, PRP was applied into the wound, and the contralateral site served as control. The healing was evaluated clinically and histologically at 1 week, 2 weeks, and 4 weeks after surgeries. Exact binomial probability and Wilcoxon signed-rank test were used to compare the clinical and histologic measurements.

RESULTS

No statistically significant differences between PRP and control sites were measured with regard to clinical healing (p = 1.000) and histologic variables, including inflammatory cells (p = .750), collagen fibers (p = .375), and granulation tissue (p = .500) at any time interval.

CONCLUSION

The addition of PRP to palatal mucosal wound sites did not accelerate wound healing.

Clinical and histological evaluation of an acellular dermal matrix allograft in combination with the coronally advanced flap in the treatment of Miller class I recession defects: an experimental study in the mini-pig

OBJECTIVES

To study the wound healing of acellular dermal matrix (ADM) allografts when used together with coronally advanced flaps (CAF) in the treatment of localized gingival recessions in the mini-pig experimental model.

MATERIAL AND METHODS

Dehiscence defects 4 x 5 mm were surgically created in one buccal root surface in each quadrant of PI, II, or III in three mini-pigs. They were then treated with CAF and the interposition of either a connective tissue graft (CTG) or ADM. As the primary outcome, the histological interface between the ADM and the root surface was studied and was compared with CTG. As secondary outcomes, we assessed the amount and quality of the keratinized tissue and clinical outcomes in terms of root coverage and recession reduction.

RESULTS

At 3 months, the CTG group attained a mean 76% root coverage, versus 62% in the ADM group. The histological interface with the root surface was similar in both groups. The apical migration of the epithelium was 1.79+/-0.46 mm for the CTG and 1.21+/-0.35 mm for ADM. Newly formed cementum was observed with both treatments. New bone and a newly formed periodontal ligament were shown in five specimens in the ADM group and in three in the CTG group.

CONCLUSION

Both materials showed similar clinical and histological outcomes.