High-density Polytetrafluoroethylene Research Articles

Alveolar Ridge Preservation with The Use of Demineralized Bone Matrix Putty: Clinical, Radiographic and Histological Observations in A Case Series

<p>Alveolar ridge preservation (ARP) can minimize alveolar ridge resorption following tooth ex¬traction and facilitate restorative-driven implant placement. Demineralized bone matrix (DBM) comprises a human allograft that is osteoinductive and osteoconductive. This report describes radiographic, histologic and clinical findings of ARP using DBM putty and non-resorbable high-density polytetrafluoroethylene (d-PTFE) membrane in three cases. </p> <p>Materials and Methods: From January 2018 to May 2018, three patients underwent the ARP procedure. The surgery involved atraumatic extraction, socket debridement, filling the socket with DBM putty, applying a d-PTFE membrane, and suturing with 5-0 nylon. After healing for 6–7 months, an implant was placed and biopsy specimens were collected simultaneously. Using the same customized surgical stent and computed tomography, the preoperative and postoperative alveolar ridge heights and widths were measured. Histological evaluations in¬cluding the percentage of newly formed bone, residual graft particles, and fibrous connective tissue were performed. </p> <p>Results: In all three cases, the health status of the hard and soft tissue improved (mean fol¬low-up: 54 months). Guided bone regeneration was not required during implant placement. Radiographically, the mean change was 0.5 mm in the alveolar ridge height and 1.2, 0.87, and 0.73 mm in the alveolar ridge width at 2, 4, and 6 mm apical to the initial vertical measure¬ment, respectively. Histologically, the mean percentage of new bone, residual graft particles, and fibrous connective tissue was 40.5±5.9%, 10.7±6.9%, and 48.8±9.6%, respectively, and the voids were not included in these calculations. </p> <p>Conclusion: This case series demonstrated the effectiveness of DBM putty as a biocompatible filler in extraction sockets for ridge preservation prior to implantation. Further longitudinal studies regarding the efficacy and stability of DBM putty in ridge preservation are required.</p> <p> </p>

New Perspective on the Mobilization of Microplastics through Capillary Fringe Fluctuation in a Tidal Aquifer Environment

The presence of plastic fragments in the environment is a growing global concern. In this study, we explored the effects of dynamic fluctuations of capillary fringe on the transport of microplastics (MPs) in the substrate combining various environmental and MP properties. Both experimental and Hydrus-2D modeling results confirmed that increasing cycles of water table fluctuation led to the rise of capillary fringe. An increase in the cycles of water table fluctuations did not significantly change the overall MP retention percentages in 0.5 mm substrate but altered the MP distribution along the column. In 1 and 2 mm substrate, the increase in cycle numbers enhanced the MP transport from substrate to the water below. In terms of the size of the MPs, more 20-25 μm polyethylene (PE2) were retained in the substrate compared to 4-6 μm polyethylene (PE1) under the same number of fluctuation cycles. High-density polytetrafluoroethylene (PTFE, 5-6 μm) exhibited higher retention percentages compared to PE1 particles. Ultraviolet aging for 60 days enhanced PE1 transport along the column, while 60 days of seawater aging did not affect PE1 transport greatly. For PTFE, ultraviolet and seawater aging enhanced its retention in the substrate. The retention percentages of both PE1 and PTFE in the column increased with the elevated ionic strength and the decrease of fluctuation velocity. This work highlights that capillary fringe fluctuation can serve as a pathway to relocate MPs to the tidal aquifer.

Reconstruction of vertical alveolar ridge deficiencies utilizing a high-density polytetrafluoroethylene membrane /clinical impact of flap dehiscence on treatment outcomes: case series/

ObjectivesThe aim of this study was to evaluate the effects of membrane exposure during vertical ridge augmentation (VRA) utilizing guided bone regeneration with a dense polytetrafluoroethylene (d-PTFE) membrane and a tent-pole space maintaining approach by registering radiographic volumetric, linear and morphological changes.MethodsIn 8 cases alveolar ridge defects were accessed utilizing a split-thickness flap design. Following flap elevation VRA was performed with tent-pole space maintaining approach utilizing the combination of a non-reinforced d-PTFE membrane and a composite graft (1:1 ratio of autogenous bone chips and bovine derived xenografts). Three-dimensional radiographic evaluation of hard tissue changes was carried out with the sequence of cone-beam computed tomography (CBCT) image segmentation, spatial registration and 3D subtraction analysis.ResultsClass I or class II membrane exposure was observed in four cases. Average hard tissue gain was found to be 0.70 cm3 ± 0.31 cm3 and 0.82 cm3 ± 0.40 cm3 with and without membrane exposure resulting in a 17% difference. Vertical hard tissue gain averaged 4.06 mm ± 0.56 mm and 3.55 mm ± 0.43 mm in case of submerged and open healing, respectively. Difference in this regard was 14% between the two groups. Horizontal ridge width at 9-month follow-up was 5.89 mm ± 0.51 mm and 5.61 mm ± 1.21 mm with and without a membrane exposure respectively, resulting in a 5% difference.ConclusionsWith the help of the currently reported 3D radiographic evaluation method, it can be concluded that exposure of the new-generation d-PTFE membrane had less negative impact on clinical results compared to literature data reporting on expanded polytetrafluoroethylene membranes.

Histomorphometry of Bone after Intentionally Exposed Non-Resorbable d-PTFE Membrane or Guided Bone Regeneration for the Treatment of Post-Extractive Alveolar Bone Defects with Implant-Supported Restorations: A Pilot Randomized Controlled Trial.

Aim: The aim of the present study was to investigate quantitative histological examination of bone reconstructed with non-resorbable high-density polytetrafluoroethylene membrane (d-PTFE), left intentionally exposed in post extraction sockets grafted with anorganic bone material, and removed after four weeks, versus extraction and guided bone regeneration (GBR), performed two months later. Materials and Methods: This study was designed as a multicenter randomized controlled trial of parallel-group design. Patients were selected and consecutively treated in three centers in Italy. Patients randomly received intentionally exposed non-resorbable d-PTFE membrane (group A), or guided bone regeneration (group B), to treat post-extractive alveolar bone defects with implant-supported restorations. Outcomes were: the implant failure, any mechanical and biological complications, patient satisfaction, and qualitative and histomorphometric evaluation of the collected bone samples. Results: Eighteen patients were consecutively enrolled in the trial. Of these, six out of 18 patients were male. All the included patients were treated according to the allocated interventions, and no drop out occurred. No implant failure and no complications were experienced, and all the patients were fully satisfied with the function and aesthetic of their implant-supported restoration, without difference between groups. Morphological analysis revealed no sign of tissue reaction, such as fibrosis or necrosis. Regenerated bone was well mineralized in both groups, but it seemed more mature in group B than in group A. Three samples showed a minimal number of lymphocytes. Several blood vessels of small size occupied the medullary spaces, where the tissue resulted in more maturity, indicating the activity of the tissue in progress. The histomorphometric evaluation showed no statistically significant differences in the tissue volume fractions between the two groups of patients. Conclusions: With the limitation of the present study, buccal plate reconstruction with an intentionally exposed non-resorbable membrane is an effective and easy procedure for regenerating a resorbed buccal bone plate, reducing the need for guided bone regeneration.

Effect of Different Membranes on Vertical Bone Regeneration: A Systematic Review and Network Meta-Analysis.

This study is aimed at performing a systematic review and a network meta-analysis of the effects of several membranes on vertical bone regeneration and clinical complications in guided bone regeneration (GBR) or guided tissue regeneration (GTR). We compared the effects of the following membranes: high-density polytetrafluoroethylene (d-PTFE), expanded polytetrafluoroethylene (e-PTFE), crosslinked collagen membrane (CCM), noncrosslinked collagen membrane (CM), titanium mesh (TM), titanium mesh plus noncrosslinked (TM + CM), titanium mesh plus crosslinked (TM + CCM), titanium-reinforced d-PTFE, titanium-reinforced e-PTFE, polylactic acid (PLA), polyethylene glycol (PEG), and polylactic acid 910 (PLA910). Using the PICOS principles to help determine inclusion criteria, articles are collected using PubMed, Web of Science, and other databases. Assess the risk of deviation and the quality of evidence using the Cochrane Evaluation Manual, and GRADE. 27 articles were finally included. 19 articles were included in a network meta-analysis with vertical bone increment as an outcome measure. The network meta-analysis includes network diagrams, paired-comparison forest diagrams, funnel diagrams, surface under the cumulative ranking curve (SUCRA) diagrams, and sensitivity analysis diagrams. SUCRA indicated that titanium-reinforced d-PTFE exhibited the highest vertical bone increment effect. Meanwhile, we analyzed the complications of 19 studies and found that soft tissue injury and membrane exposure were the most common complications.

Alveolar ridge augmentation by open healing with high-density polytetrafluoroethylene membrane

Non resorbable polytetrafluoroethylene membranes find great use in everyday oral surgery treatments. We aimed to verify the performance of high-density polytetrafluoroethylene (hdPTFE) membrane in open healing after alveolar ridge augmentation at two patients. For that reason, we raised full thickness flap and grafted with different xenograft granules that were covered with resorbable collagen membrane. Then the grafted area was covered with high-density polytetrafluoroethylene membrane (permamem®) and stabilized with sutures by leaving it partially exposed. Six weeks after open healing, the permamem® was removed and successful post-operative healing with no complications were observed. The newly formed soft tissue grew under the membrane and completely covered the new alveolar ridge volume. There were no signs of dehiscence or infection, and the patients had no pain or discomfort, neither after suture nor the membrane removal. Also, there were no visible signs of bacterial plaque on the membrane after its placement and during removal. After eight months implants were successfully installed, and full mouth prosthetic reconstruction was following the osseointegration. In conclusion, the high-density polytetrafluoroethylene membrane efficiently supported open healing and led to successful alveolar ridge augmentation.

Socket preservation with high-density polytetrafluoroethylene barrier membrane during open healing

Bone volume loss appears after tooth extraction and socket preservation is the most applied procedure to prevent an alveolar resorption. The aim of this study was to retrospectively analyse three socket preservation cases with high-density polytetrafluoroethylene barrier membrane (permamem®) for open healing with and without the use of additional dental regeneration biomaterials. Here no bacterial plaque was present and the soft tissue completely re-epithelialized, which allowed new bone formation and implant treatment. The current findings indicate that the use of this membrane, leads to successful socket treatment during open healing.

Effectiveness of bilayer porous polyethylene membrane for alveolar ridge preservation: A randomized controlled trial.

Porous polyethylene has been successfully used in several medical applications with good outcomes. Based on this, a new bilayer porous polyethylene membrane (B-PPM) was developed for possibly being used as a membrane in alveolar ridge preservation. To evaluate the clinical efficacy of a new B-PPM in comparison to high-density polytetrafluoroethylene membrane (d-PTFE) in alveolar ridge preservation. Thirty patients were randomized into two groups according to the membranes used to cover the socket (B-PPM or d-PTFE). Wound healing was monitored at day 1, 3, 7, 14, 28, and 4 months postoperatively. Dimensional changes of alveolar ridge were measured immediately after tooth extraction and at 4 months later using intraoral scanner and cone beam computed tomography. Bone cores were harvested before implant placement. Implant stability at insertion and prior to prosthesis delivery were also measured. No significant difference in socket wound closure between groups was observed excepting at day 14 that B-PPM showed a faster wound closure than d-PTFE (P = .03). Greater bone resorptions were seen on buccal than lingual side and on coronal than apical part of the alveolar ridge. No significant difference in dimensional changes of alveolar ridge, new bone formation, connective tissue content, residual bone grafts, and implant stability between two groups. B-PPPM was safe and effective for alveolar ridge preservation.

Guided bone regeneration in staged vertical and horizontal bone augmentation using platelet-rich fibrin associated with bone grafts: a retrospective clinical study

BackgroundThe use of guided bone regeneration (GBR) for vertical and horizontal bone gain is a predictable approach to correct the bone defects before implant installation; however, the use of different protocols is associated with different clinical results. It is suggested that platelet-rich fibrin (PRF) could improve the outcomes of regenerative procedures. Thus, this study aimed to describe the bone gain associated with GBR procedures combining membranes, bone grafts, and PRF for vertical and horizontal bone augmentation.Materials and methodsEighteen patients who needed vertical or horizontal bone regeneration before installing dental implants were included in the study. The horizontal bone defects were treated with a GBR protocol that includes the use of a mixture of particulate autogenous and xenogenous grafts in the proportion of 1:1, injectable form of PRF (i-PRF) to agglutinate the graft, an absorbable collagen membrane covering the regenerated region, and leukocyte PRF (L-PRF) membrane covering the GBR membrane. The vertical bone defects were treated with the same grafted mixture protected by a titanium-reinforced non-resorbable high-density polytetrafluoroethylene (d-PTFE-Ti) membrane and covered by L-PRF. The bone gain was measured using a cone-beam computed tomography at baseline and after a period of 7.5 (± 1.0) months.ResultsAll patients underwent surgery to install implants after this regenerative protocol. The GBR produces an increase in bone thickness (p < 0.001) and height (p < 0.005) after treatment, with a bone gain of 5.9 ± 2.4 for horizontal defects and 5.6 ± 2.6 for vertical defects. In horizontal defects, the gain was higher in the maxilla than in mandible (p = 0.014) and in anterior than the posterior region (p = 0.033). No differences related to GBR location were observed in vertical defects (p > 0.05).ConclusionGBR associated with a mixture of particulate autogenous and xenogenous grafts and i-PRF is effective for vertical and horizontal bone augmentation in maxillary and mandibular regions, permitting sufficient bone gain to future implant placement.Trial registrationREBEC, RBR-3CSG3J. Date of registration—19 July 2019, retrospectively registered. http://www.ensaiosclinicos.gov.br/rg/RBR-3csg3j/

Vertical-guided bone regeneration with a titanium-reinforced d-PTFE membrane utilizing a novel split-thickness flap design: a prospective case series

ObjectivesTo evaluate the feasibility of a newly proposed minimally invasive split-thickness flap design without vertical-releasing incisions for vertical bone regeneration performed in either a simultaneous or staged approach and to analyze the prevalence of adverse events during postoperative healing.Materials and methodsFollowing preparation of a split-thickness flap and bilaminar elevation of the mucosa and underlying periosteum, the alveolar bone was exposed over the defects, vertical GBR was performed by means of a titanium-reinforced high-density polytetrafluoroethylene membrane combined with particulated autogenous bone (AP) and bovine-derived xenograft (BDX) in 1:1 ratio. At 9 months after reconstructive surgery, vertical and horizontal hard tissue gain was evaluated based on clinical and radiographic examination.ResultsTwenty-four vertical alveolar ridge defects in 19 patients were treated with vertical GBR. In case of 6 surgical sites, implant placement was performed at the time of the GBR (simultaneous group); in the remaining 18 surgical, sites implant placement was performed 9 months after the ridge augmentation (staged group). After uneventful healing in 23 cases, hard tissue fill was detected in each site. Direct clinical measurements confirmed vertical and horizontal hard tissue gain averaging 3.2 ± 1.9 mm and 6.5 ± 0.5 mm respectively, in the simultaneous group and 4.5 ± 2.2 mm and 8.7 ± 2.3 mm respectively, in the staged group. Additional radiographic evaluation based on CBCT data sets in the staged group revealed mean vertical and horizontal hard tissue fill of 4.2 ± 2.0 mm and 8.5 ± 2.4 mm. Radiographic volume gain was 1.1 ± 0.4 cm3.ConclusionVertical GBR consisting of a split-thickness flap and using titanium-reinforced non-resorbable membrane in conjunction with a 1:1 mixture of AP+BDX may lead to a predictable vertical and horizontal hard tissue reconstruction.Clinical relevanceThe used split-thickness flap design may represent a valuable approach to increase the success rate of vertical GBR, resulting in predicable hard tissue regeneration, and favorable wound healing with low rate of membrane exposure.

Ridge Preservation Procedures: Review of Current Literature

Alveolar ridge preservation (ARP) procedures have become one of the most commonly performed surgical procedures in dentistry, due to increased demand for dental implant therapy. Previous studies have repeatedly shown a naturally healed socket could lose up to 50% of its buccolingual width, which in turn would negatively impact the future implant placement. ARP procedures have been shown to consistently reduce the amount of post-extraction horizontal and vertical bone loss; however, it is still not conclusive which biomaterial or technique is the most superior. The purpose of this article is to review current evidence on various ARP procedures. The electronic database search was limited to the past 3 years (publication dates between January 1, 2017, and February 29, 2020) and to human clinical studies (including controlled clinical trials and randomized controlled trials) investigating dimensional changes in alveolar sockets after various ARP techniques with outcomes measured from 3 to 6 months postoperatively. A total of 31 articles were reviewed, with approximately half of the selected studies using bovine (14) bone substitutes. Other biomaterials used in the studies included porcine bone substitutes, allografts (both freeze-dried and solvent-dehydrated), alloplasts (biphasic calcium phosphate, β-tricalcium phosphate, and hydroxyapatite), biologics (platelet-rich fibrin and recombinant bone morphogenetic protein-2), collagen and high-density polytetrafluoroethylene membranes, and micro-titanium stent. Collagenated deproteinized bovine bone matrix (DBBM-C) was the most studied biomaterial in the past 3 years. Most studies showed DBBM-C plus barrier membranes resulted in comparable clinical and radiographic outcomes with DBBM and allografts. Consistent with previous studies, most of the ARP procedures reviewed in this article demonstrated effective reduction of alveolar ridge dimensional changes. Based on the selected articles and recent systematic reviews and meta-analysis, ARP procedure using bovine and porcine xenografts, as well as allografts, in conjunction with either collagen membranes or high-density polytetrafluoroethylene membranes gives similar results and should be considered when indicated.

An update on the utilization of high-density polytetrafluoroethylene (d-PTFE) membranes for guided bone regeneration

Guided bone regeneration (GBR) procedure has produced acceptable results while utilizing various barrier membranes. Among the membranes used, expanded PTFE (e-PTFE) was the first material to demonstrate successful outcomes and it became the gold standard for GBR. However, early bacterial infection with membrane exposure affecting bone regeneration was the main drawback of e-PTFE. On the contrary, high density polytetrafluoroethylene (d-PFTE) ensures a good bone regeneration process in spite of membrane exposure in the oral cavity, and it also presents with a lower risk of early infection after surgical procedures. The purpose of this review is to provide an amendment to the existing knowledge about the GBR with special emphasis on the d-PTFE barrier membrane used for GBR. The relevant literature for this review was identified through a PubMed, MEDLINE, Scopus, and the Cochrane Library database search. Eleven articles that evaluated the use of d-PTFE as a barrier membrane for GBR were identified: two experimental studies and nine clinical studies. Considering the potential benefit they offer, d-PTFE is a favorable candidate for GBR. However, a careful surgical approach and thorough knowledge of the materials and management of complications significantly contribute to the success of GBR while utilizing d-PTFE.

Çekim Soketlerinin Ogmentasyonunda Primer Kapamaya Karşı Açık Membran Tekniği

Objectives: Funakoshi is the first one who reported 'Open Barrier Membrane' technique by using non-expanded, highdensity polytetrafluoroethylene(d-PTFE) membrane in 2005. d-PTFE membranes are impenetrable for bacteria invasion because of its surface characteristics and surgeon can leave the d-PTFE membrane intentionally exposed. The objective of this study was to investigate the clinical results of 'Open Barrier Membrane' technique in Guided Bone Regeneration (GBR) of the extraction sockets by using xenogenic bone graft and d-PTFE membranes. In this clinical study, open barrier membrane technique was compared to GBR technique. The comparison was made between the cases where the primary coverage of extraction site was obtained and the cases who completed the 6-month recovery period without exposure in terms of total bone gain. Material and Methods: Fifteen patients who were reported to have exposure in incision line during 6-month recovery period were included in open membrane group as study group (Group A). Fifteen patients who completed the 6-month recovery period without exposure were analyzed in primary coverage group as control group (Group B). The main groups were also divided into subgroups as horizontal and vertical augmentation. The amount of total bone gain was statistically compared between the groups based on the cone beam computerized tomography measurements. Results: Vertical and horizontal bone gain amounts (the main outcome variable) were statistically compared between Group A and B. There was no statistically significant difference between these groups in terms of bone gain (p=0.237 for comparison of vertical augmentation; p=0.482 for comparison of horizontal augmentation). Conclusion: Open barrier membrane technique can be considered as an alternative minimal invasive technique for both horizontal and vertical alveolar augmentation procedures.

Microbiological and FE-SEM Assessment of d-PTFE Membrane Exposed to Oral Environment after Alveolar Socket Preservation Managed with Granular nc-HA

The aim of this study was to analyze, by the aid of microbiological analysis and the field emission scanning electron microscopical (FE-SEM) analysis, the role of high-density polytetrafluoroethylene (d-PTFE) membranes in avoiding the microbial colonization of a nanocrystalline hydroxyapatite (nc-HA) bone graft and the involvement of this colonization in the healing process. Six patients underwent extraction of unrecoverable teeth, and a socket preservation technique was carried out with nc-HA synthetic bone graft and then covered with a d-PTFE membrane. After 28 days from surgery, FE-SEM analysis and BioTimer assay technique to assess the microbiological count of streptococci species were carried out. Data were collected and analyzed by the Student's t test (confidence interval: 95%). The mean amount of bacteria measured on the upper side of the membrane was 6.52 ± 0.50 CFU, while on the lower side, it was 6.59 ± 0.40 CFU. Significant differences were not found between the two sides of the membrane or between the different sectors (p > 0.05). The FE-SEM analysis revealed structured biofilms on both sides of the membrane: species of cocci, bacilli, and fusobacteria were recognizable in occasional settled vegetations. Since the amount of bacteria found was low, the improved impermeability of the d-PTFE membrane permitted the healing process to proceed uneventful and without signs of infection or inflammation. The infection of the graft site could lead to a failure of the socket preservation technique which could delay or compromise the rehabilitation following procedures. The use of d-PTFE can improve the bone regeneration thanks to its antimicrobial properties.

Periosteal Inhibition Technique for Alveolar Ridge Preservation as It Applies to Implant Therapy.

Alveolar ridge preservation procedures have been shown to significantly reduce the loss of ridge dimension of an extraction socket. As of yet, none of the alveolar ridge preservation techniques have been proven totally effective in preserving ridge morphology. The Periosteal Inhibition technique for alveolar ridge preservation involves placing a high-density polytetrafluoroethylene (d-PTFE) membrane between the periosteum and the buccal bone plate of an extraction socket. The authors hypothesize that the nonresorbable d-PTFE membrane, because of its much smaller pore diameter as compared to the size of the osteoclast precursor cells, inhibits the migration of the osteoclast precursor cells from the periosteum to the bony surface and, subsequently, their fusion to form osteoclasts. As a result, osteolytic activity on the outer surface of the socket is inhibited. The Periosteal Inhibition technique for alveolar ridge preservation is presented along with immediate implant treatment results using this treatment concept. The resulting stable ridge dimensions in these cases demonstrate a possibility that the d-PTFE membrane may effectively prevent modeling of the extraction socket by inhibiting the formation of osteoclasts on the outer bony surface.

Management Of 80 Complications In Vertical And Horizontal Ridge Augmentation With Nonresorbable Membrane (d-PTFE): A Cross-Sectional Study.

Vertical and horizontal guided bone regeneration with nonresorbable membranes is a regenerative alternative for treating bone defects in edentulous zones. Its indication and good outcomes have been confirmed by different authors; however, this procedure remains highly technique sensitive and might lead to complications. The purpose of this study was to describe the management of complications such as exposures and infections following vertical and horizontal guided bone regeneration with titanium-reinforced high-density polytetrafluoroethylene (PTFE) nonresorbable membranes carried out using a new management protocol for complications related to this type of membrane. Complications in vertical and horizontal guided bone regeneration were evaluated by the same surgeon in a private practice between 2010 and 2017. They were classified and managed according to whether they were exposures and/or infections, and also according to their size, sagittal location, and coronal position of the alveolar ridge of the exposures. Descriptive analyses were conducted to evaluate the influence of age, sex, clinical characteristics of the complication, time of appearance, location, membrane size, anatomical and sagittal location, pink ceramic use, and definitive restoration, both before and after management protocol application. Eighty complications were evaluated. The sextant with the highest number of complications was the anterior maxilla (35/80, 43.75%), followed by the mandibular left side area (16/80, 20.00%). The majority (56/80, 70.00%) of all complications appeared before 2 months. In relation to the sagittal location of exposures, 43.64% (24/55) were located coronal to the alveolar ridge. Statistically significant differences were found between exposures with or without purulent exudate, related to the coronal location of the exposure (P ± .05). A new protocol for managing complications with titanium-reinforced high-density PTFE nonresorbable membranes is proposed based on the follow-up of 80 complications. These steps can help prevent total graft loss, allowing patients to reach final rehabilitation without multiple additional surgeries. Infections continue to be the most common cause of bone loss in guided bone regeneration. Long-term results and follow-up studies are necessary to assess the stability of soft and hard tissues in patients rehabilitated using this complication management protocol.

Retrospective comparative clinical study for silk mat application into extraction socket

BackgroundSilk mats have been approved for clinical trials by the Korean Food and Drug Administration as membranes for guided tissue regeneration (GTR). In this study, silk mat application was compared to high-density polytetrafluoroethylene (dPTFE) membrane application or no membrane group.MethodsTo compare the silk mat group to the dPTFE group or the no membrane group, a retrospective sample collection was conducted. Bony defects were measured at the time of extraction (T0) and then at 3 months (T1) and 6 months after extraction (T2) on a digital panoramic view. Bone gain (BG) was calculated by subtracting from the bony defect at T0 to the bony defect at each follow-up.ResultsThe BG at T2 was 2.44 ± 2.49 mm, 4.18 ± 1.80 mm, and 4.24 ± 2.05 mm in the no membrane group, silk mat group, and dPTFE group, respectively. Both membrane groups had significantly higher BG than BG in the no membrane group at T2 (P < 0.05).ConclusionsBoth membrane groups showed higher BG than the no membrane group.

Clinical Study for Silk Mat Application into Extraction Socket: A Split-Mouth, Randomized Clinical Trial

Silk mat originates from the cocoon of the silkworm and is prepared by a simple method. The material has been used for guided bone regeneration (GBR) in animal models. In this study, the silk mat used for a clinical application was compared with a commercially available membrane for GBR. A prospective split-mouth, randomized clinical trial was conducted with 25 patients who had bilaterally impacted lower third molars. High-density polytetrafluoroethylene (dPTFE) membrane or silk mat was applied in the extraction socket randomly. Probing depth (PD), clinical attachment level (CAL), and bone gain (BG) were measured at the time of extraction (T0) and then at three months (T1) and six months after extraction (T2). There was no missing case. GBR with silk mat was non-inferior to GBR with dPTFE for PD reduction at T1 and T2 (pnon-inferiority &lt; 0.001). PD and CAL were significantly decreased at T1 and T2 when compared with those at T0 in both membrane groups (p &lt; 0.001). BG at T2 was 3.61 ± 3.33 mm and 3.56 ± 3.30 mm in the silk mat group and dPTFE group, respectively. There was no significant complication from the use of silk mat for the patients. The results for patients undergoing GBR with silk mat for third-molar surgery were non-inferior to GBR with dPTFE for PD reduction.

Photoluminescence of the integrating sphere walls, its influence on the absolute quantum yield measurements and correction methods

Determination of the absolute quantum yield (QY) of photoluminescence (PL) or electroluminescence is commonly performed using an integrating sphere (IS) – versatile device for radiometry applications. The key feature of IS is very high diffused reflectance of its internal surface. Two materials are commonly used: (a) the sintered high-density polytetrafluoroethylene (Spectralon) and (b) materials based on barium sulphate (Spectraflect). Using PL-micro-spectroscopy we show that both materials reveal PL from localized centers excitable by UV, blue and green light emitting broad PL spectrum extending up to the red spectral region. The main effect of PL from IS-walls is introduction of non-constant parasitic background which is mixed with PL from a tested sample during the QY measurements. We develop theoretical description of QY determination which includes effects of PL from IS walls. This allows us to propose and test a reliable and universal correction for the IS-related PL background. Finally, a method of “black sample” is proposed and applied to estimate PL QY of Spectraflect which is shown to decrease from 0.09 to 0.015% for excitation shift from 320 to 440 nm.

In Vivo Analysis of the Biocompatibility and Macrophage Response of a Non-Resorbable PTFE Membrane for Guided Bone Regeneration.

The use of non-resorbable polytetrafluoroethylene (PTFE) membranes is indicated for the treatment of large, non-self-containing bone defects, or multi-walled defects in the case of vertical augmentations. However, less is known about the molecular basis of the foreign body response to PTFE membranes. In the present study, the inflammatory tissue responses to a novel high-density PTFE (dPTFE) barrier membrane have preclinically been evaluated using the subcutaneous implantation model in BALB/c mice by means of histopathological and histomorphometrical analysis methods and immunohistochemical detection of M1- and M2-macrophages. A collagen membrane was used as the control material. The results of the present study demonstrate that the tissue response to the dPTFE membrane involves inflammatory macrophages, but comparable cell numbers were also detected in the implant beds of the control collagen membrane, which is known to be biocompatible. Although these data indicate that the analyzed dPTFE membrane is not fully bioinert, but its biocompatibility is comparable to collagen-based membranes. Based on its optimal biocompatibility, the novel dPTFE barrier membrane may optimally support bone healing within the context of guided bone regeneration (GBR).