The impact of membrane perforation and L-PRF for vertical ridge augmentation with a xenogeneic block graft: an experimental study in a canine model.

OBJECTIVES: This study evaluated clinically and histologically the efficacy of modified perforated collagen membrane (PCM) and/or leukocyte- and platelet-rich fibrin (L-PRF) in combination with xenogeneic block bone graft in the vertical alveolar ridge augmentation. MATERIALS AND METHODS: Six adult mongrel dogs were enrolled in this randomized blinded study. After defect preparation, xenogeneic screw-fixed block graft was covered by an occlusive collagen membrane in group 1 that represented the control group (Block + CM). In group 2, L-PRF membrane was added first before top coverage by occlusive collagen membrane (Block + L-PRF + CM). Groups 3 (Block + PCM) and 4 (Block + L-PRF + PCM) were identical to the first two groups except that the occlusive collagen membrane was replaced by a perforated one. Following a healing period of 2 months, the dogs were submitted to the surgical reentry phase for clinical and histological evaluation. RESULTS: Clinically, no significant differences were found among all groups regarding vertical and horizontal ridge dimensions (p = 0.155, 0.492, respectively). Histomorphometric analysis revealed that the percentage of the total bone area and mature bone was significantly higher in group 4 (69.36 ± 2.72, 33.11 ± 5.18) compared to the control group (59.17 ± 4.27, 21.94 ± 2.86) (p = 0. 027, p = 0.029). CONCLUSION: The use of xenogenic block grafts in combination with a double-layered perforated collagen L-PRF membrane in vertical ridge augmentation appeared to improve the inductive power of this challenging defect type. CLINICAL RELEVANCE: Size and number of perforations may affect the mechanical and handling properties of the membrane.

Adjunctive effect of collagen membrane coverage to L-PRF in the treatment of periodontal intrabony defects: a randomized controlled clinical trial with biochemical assessment.

BACKGROUND: The innovation of leukocyte platelet-rich fibrin (L-PRF) has added enormous impact on wound healing dynamics especially the field of periodontal regeneration. The release of growth factors (GF) is thought to improve the clinical outcomes in infrabony defects. The aim of this study was to evaluate the clinical effect of covering L-PRF contained infrabony defects with collagen membranes (CM), and to compare their GF release profile to uncovered L-PRF defects and open flap debridement (OFD). METHODS: Thirty non- smoking patients with infrabony pockets participated to be randomly assigned to OFD group (n = 10), L-PRF group (n = 10), or L-PRF protected CM group (n = 10). Plaque index (PI), gingival index (GI), probing depth (PD), clinical attachment level (CAL) and the radiographic defect base fill (DBF) were measured at baseline and at 6 month following surgical intervention. Gingival crevicular fluid samples were obtained on days 1, 3, 5, 7, 14, 21 and 30 days following surgery for the Platelet Derived Growth Factor-BB (PDGF-BB) and Vascular Endothelial Growth Factors (VEGF) release profile evaluation. RESULTS: For all patients, a statistically significant (P ≤ 0.05) reduction in PI, GI, PD and CAL were reported throughout the study period. Differences between the three treatment modalities were not statistically significant. PRF + CM showed a statistically significant DBF compared to OFD and L-PRF groups at follow up. Quantitative analysis of PDGF-BB and VEGF levels demonstrated a statistically significant (P < 0.001) decline between measurement intervals for all groups with no statistically significant differences between the three groups. CONCLUSION: Within the limitations of this study, L-PRF coverage with CM may augment defect base fill through its mechanical protective effect without enhancement in the release profile of VEGF and PDGF. The non-significant intergroup differences question the validity of the claimed extra physiologic concentration of GF offered by L-PRF harvests. TRIAL REGISTRATION: The present study was registered at ClinicalTrials.gov (NCT05496608), (11/08/2022).

Guided tissue regeneration of intrabony defects with perforated barrier membranes, simvastatin, and EDTA root surface modification: A clinical and biochemical study.

BACKGROUND: Perforated barrier membranes (PBM) were suggested to enhance periodontal regeneration by allowing positive charity of wanted elements from the gingival tissue side. The present study was designed to evaluate clinically and biochemically the use of PBM combined with simvastatin (SMV) gel with and without an associated EDTA gel root surface etching as a suggested option that could improve SMV availability and clinical outcomes of PBM. METHODS: Forty patients having moderate-to-severe chronic periodontitis with 40 intrabony defects were randomly divided into four treatment groups (10 sites each). Patients in group 1 received 1.2% SMV gel and covering the defect with occlusive membrane (OM). Patients in group 2 received 1.2% SMV gel and covering the defect with PBM. Group 3 received 24% EDTA root surface etching, 1.2% SMV gel, and defect coverage with OM (eOM). Patients in group 4 were treated as in group 3 but the defect was covered with PBM (ePBM). Clinical parameters were recorded at baseline before surgical procedures and were reassessed at 6 and 9 months after therapy. The mean concentration of SMV in gingival crevicular fluid (GCF) was estimated by reverse-phase high-performance liquid chromatography at days 1, 7, 14, 21, and 30. RESULTS: At 6- and 9-month observation periods, groups 3 and 4 showed a statistically significant improvement in PD reduction and CAL gain compared with groups 1 and 2. Group 4 showed a statistically significant more defect fill compared with groups 1, 2, and 3 (P ≤ .05). Group 2 showed statistically significant higher defect fill compared with group 1 and group 3 (P < .05). Bone density was significantly increased with no significant difference between the four groups at 6- and 9-month observation periods. SMV-GCF concentration in group 4 showed the highest mean concentration with no significant difference than that of group 3. CONCLUSION: The use of perforated barrier membranes in association with SMV enhances the clinical hard tissue parameters compared with occlusive ones in treating intrabony periodontal defects. Moreover, EDTA root surface treatment could enhance SMV availability in the defect area.

Regenerative potential of cultured gingival fibroblasts in treatment of periodontal intrabony defects (randomized clinical and biochemical trial).

BACKGROUND: Defective cellular elements constitute an important challenge to achieve predictable periodontal regeneration. In an attempt to improve the cellularity of periodontal defects, gingival fibroblasts were implanted without their associated extracellular elements in periodontal defects to expose them to periodontal tissue mediators. In order to investigate the regenerative potential of gingival fibroblasts translocated into periodontal defects, the present study was designed to clinically and biochemically investigate the use of gingival fibroblasts (GF) and their associated mesenchymal stem cells (GMSC) in the treatment of intrabony periodontal defects. METHODS: A total of 20 subjects were randomly divided into two groups (n = 20). Group I: ten patients were included with ten intrabony periodontal defects that received ß-calcium triphosphate (ß-TCP) followed by collagen membrane defect coverage, while group II: (10 patients) ten periodontal defects received cultured gingival fibroblasts (GF) on the ß-TCP scaffold and covered by a collagen membrane. The clinical evaluation was carried out at the beginning and at 6 months. Gingival crevicular fluid (GCF) samples were collected directly from the test sites for the quantitative measurement of PDGF-BB and BMP-2 using the ELISA kit at 1, 7, 14, and 21 days after surgery. RESULTS: Group II reported a significantly greater reduction in vertical pocket depth (VPD) and CAL gain compared with group I after 6 months. Radiographic bone gain was statistically higher in group II compared with group I. A significantly higher concentration of PDGF-BB was observed in group II on days 1, 3, and 7 compared with group I. CONCLUSIONS: Translocation of gingival fibroblasts from gingival tissue to periodontal defects could be a promising option that increases cellular elements with regeneration potential. The concept of total isolation of gingival fibroblasts using occlusive membranes must be re-evaluated.

Lycopene solid lipid microparticles with enhanced effect on gingival crevicular fluid protein carbonyl as a biomarker of oxidative stress in patients with chronic periodontitis.

Lycopene (LP), a naturally occurring carotenoid in red-coloured fruits, especially tomatoes, has a pivotal role in counteracting the deleterious effect of oxidative stress on periodontal tissues. The aim of this study is to prepare solid lipid microparticles (SLMs) encapsulating LP and to assess their biochemical and clinical effects in the management of chronic periodontitis. Optimization of SLMs was performed by assessing particle size and LP entrapment efficiency. Clinical study included 16 chronic periodontitis patients allocated into two groups, Group I was managed by scaling and root planing (SRP) and local delivery of LP loaded SLMs, while Group II was managed by SRP only. Protein carbonyl (PC) levels as a biomarker of oxidative stress and drug concentration in gingival crevicular fluid (GCF) were assessed at different time intervals. Results revealed that optimum formula of SLMs had a particle size of 77.28 µm and entrapped 98.03% of LP. SLMs recorded 30 d of drug release with no burst effect. Patients treated with LP SLMs showed significantly lower levels of PC after SRP compared to those treated with SRP only, in addition to improvement in the measured clinical parameters. In conclusion, locally delivered LP SLMs along with SRP could have a protective effect over periodontal tissues and it has the ability to decrease oxidative damage of proteins in diseased periodontium.

Dimensional evaluation of blood clot gap distances within intrabony defects following grafting and EDTA root surface treatment-experimental study in dogs.

BACKGROUND: Because it is important to establish and maintain a firm blood clot to the surrounding tissues within the intrabony lesion; we have to investigate the potentials of different materials in resisting clot retraction that disrupt clot adhesion to the root surface. This study was designed to measure the gap distance created by clot retraction within the defect following intrabony defects grafting with and without root surface EDTA etching. METHODS: Eight mongrel dogs with surgically created acute-chronic bilateral mandibular interproximal intrabony defects in the premolar-molar areas were enrolled in this study (total 8 defects per dog). Intrabony defects were divided into four groups, the first group (OFD): control open flap debridement, the second group, (EDTA treated defects) in which debridement of the defects was followed by two minute root surface etching with a neutral 24% EDTA gel followed by two minute copious saline irrigation, the third group (only grafted defects): defects received closely packed ß-TCP of a particle size ranged from 150 to 500 mm, and the fourth group, (Graft + EDTA treated defects): defects were etched for 2 minutes with a neutral 24% EDTA gel and saline irrigation followed by intrabony defect fill of ß-TCP. Twenty four hours post treatment, animal euthanasia was carried out for histomorphometric analysis of the tooth and root side gap distances. RESULTS: EDTA treated group and EDTA + graft group showed statistically significant lower degree of clot shrinkage compared to both the control and only grafted group. Clot shrinkage in EDTA treated group showed no significant difference from that of the EDTA + graft group (p = 0.197). OFD and only grafted groups were found to show statistically higher clot retraction percnetage compared to both EDTA and EDTA+graft groups. CONCLUSION: following intrabony defect debridement, blood clot undergoes clot retraction creating a micro gap with the root surface. EDTA root surface etching before graft application into the defect area significantly reduced the amount of gap distance.

Crevicular Fluid Growth Factors Release Profile Following the Use of Platelet-Rich Fibrin and Plasma Rich Growth Factors in Treating Periodontal Intrabony Defects: A Randomized Clinical Trial.

BACKGROUND: The open, usually contaminated nature of periodontal defects could negatively affect availability and activity of platelet concentrate-suggested growth factors (GF). The aim of this study is to test this hypothesis and investigate concentrations of: 1) vascular endothelial growth factor (VEGF) and 2) platelet-derived growth factor (PDGF-BB) in gingival crevicular fluid (GCF) from localized intrabony defects treated with platelets rich in growth factors (PRGF) or platelet-rich fibrin (PRF) compared with a control xenograft defect filling. METHODS: Thirty non-smoking patients suffering severe chronic periodontitis were allocated to this randomized, prospective, single-masked trial. Each patient had one interproximal defect randomly distributed to: 1) group 1: bone-substitute grafting control (n = 10); 2) group 2: experimental PRGF (n = 10); or 3) group 3: PRF (n = 10). Clinical parameters were measured at baseline and 6 and 9 months following therapy. GCF samples were obtained on days 1, 3, 7, 14, 21, and 30 after therapy for evaluation of VEGF and PDGF-BB levels. RESULTS: On days 1, 3, and 7 following surgery, mean levels of VEGF and PDGF-BB at sites treated with PRGF and PRF were not significantly different versus the control. Levels of PDGF-BB and VEGF were higher in the PRGF-treated group, but differences were not significant. Growth factor levels decreased significantly in samples collected on days 14, 21, and 30 with non-significant differences among the three groups. No significant clinical differences were reported among the three groups during the two observation periods (early period: days 1, 3, and 7; and later period: days 14, 21, and 30). CONCLUSIONS: Within the limits of the present study, it can be concluded that PRF and PRGF platelet concentrate failed to augment clinical effects achieved with the xenograft alone in treating intrabony defects. Periodontal defects could not retain extraphysiologic levels of GF suggested to be associated with platelet concentrate.

A novel approach for enhanced nanoparticle-sized bone substitute adhesion to chemically treated peri-implantitis-affected implant surfaces: an in vitro proof-of-principle study.

BACKGROUND: The objective of this study is to evaluate micro and nano-hydroxyapatite (NHA) blended clot adhesion to citric acid-conditioned peri-implantitis-affected surfaces. METHODS: Forty hopeless implants with peri-implantitis designated for removal were included in this study. Implants were divided into eight groups of five each: group 1 (G1) test areas were coated with hydroxyapatite of a microparticle size (MHA); group 2 (G2) test areas were coated with NHA; group 3 (G3) implants were coated with MHA after surface conditioning using citric acid; group 4 (G4) samples were treated in the same manner as in G3 except for the use of NHA; group 5 (G5) samples were coated without surface treatment with MHA mixed with whole human blood; group 6 (G6) implant samples were treated in the same manner as in G5 except for the use of NHA; group 7 (G7) implant samples were treated in the same way as in G5 plus surface conditioning using citric acid; and group 8 (G8) samples were treated in the same manner as in G7 except for the use of NHA. All implants in all groups were agitated for 3 minutes in phosphate-buffered saline. All samples were prepared for scanning electron microscopy evaluation. RESULTS: G1 and G2 non-etched implants coated with MHA or NHA sizes were devoid of any bone particle adhesion to the peri-implantitis-affected surfaces. Contrary to the lack of microparticle adhesion to the root surface that was seen in G3, G4 acid-treated and NHA-coated samples revealed nearly complete coverage of the peri-implantitis-affected parts by the graft material. G5 non-etched, clot-blended MHA showed some areas of clot-blended graft adhesion covering 6.7% of the examined surfaces. G6 non-etched, clot-blended NHA showed NHA retention within the fibrin strands in areas where the implant surface pores were exposed (24.3%). G7 acid-treated and clot-blended MHA-treated implant surfaces showed partial coverage of the implant surface with detached fibrin clot-blended graft material (31.4%). G8 acid-treated and NHA clot-blended graft-coated implants showed complete coverage of the implant surface by the clot-blended graft material (93.4%). CONCLUSION: Peri-implantitis-affected surface conditioning with citric acid improves NHA-blended clot adhesion to titanium implant surfaces.