In vitro evaluation of membranes for regenerative procedures against oral bacteria

Abstract The current literature on guided bone regeneration (GBR) and guided tissue regeneration (GTR) membrane contamination reports that the physicochemical characteristics of these biomaterials might influence affinity to bacteria, which appears to be a major drawback for the clinical outcome of the regenerative procedures. Thus, this study aimed to evaluate, in vitro, a multispecies biofilm adherence and passage of bacteria through different types of commercially available membranes for GTR/GBR. Four types of membranes were tested (n=12): LC) Lumina Coat®; JS) Jason®; BG) Biogide®; and LP) Lumina PTFE®. Aluminum foil (AL) simulated an impermeable barrier and was used as the control. The membranes were adapted to specific apparatus and challenged with a mixed bacterial culture composed of A. actinomycetemcomitans b, S. mutans, S. mitis, and A. israelii. After 2 h or 7 days, bacterial adhesion and passage of bacteria were evaluated through CFU counting, which was analyzed by two-way ANOVA e post hoc Tukey, at a 5% significance level. Representative areas of two membranes of each group were analyzed through scanning electron microscopy (SEM) to assess the morphology and organization of the biofilm over the membrane fibers. LC and LP presented similar values of adhered bacterial cells (p > 0.05), significantly inferior when compared to the other groups, in both time points (p < 0.05). All the tested groups were permeable to bacterial cells, with no significant difference between the trial period of 2 h and 7 days (p > 0.05). SEM analyses demonstrated that adhered bacteria number increased throughout the time points (2 h < 7 days). Commercially available biological membranes demonstrated intense bacterial adherence and passage of bacteria, which increased throughout the trial period.

Resumo O objetivo deste estudo foi avaliar, in vitro, a aderência do biofilme multiespécie e a passagem de bactérias através dos diferentes tipos de membranas disponíveis comercialmente para RTG/ROG. Quatro tipos de membranas foram testados (n=12): LC) Lumina Coat®; JS) Jason®; BG) Biogide®; e LP) Lumina PTFE®. Papel alumínio (AL) simulou uma barreira impermeável e foi usado como controle negativo. As membranas foram adaptadas à um aparato específico e desafiadas com uma cultura bacteriana mista composta de A. actinomycetemcomitans b, S. mutans, S. mitis, e A. israelii. Após 2 h ou 7 dias, a aderência e passagem bacteriana foi avaliada através da contagem de UFCs. Duas membranas de cada grupo foram analisadas através da microscopia eletrônica de varredura (MEV). LC e LP apresentaram valores semelhantes de células bacterianas aderidas (p < 0.05), significativamente inferiores quando comparados aos outros grupos, em ambos os períodos experimentais (p < 0.05). Desde a análise inicial, todos os grupos testados foram permeáveis às células bacterianas, sem diferença significativa entre o período experimental de 2 h e 7 dias (p > 0.05). As análises em MEV demonstraram que o número de bactérias aderidas aumentou com o tempo (2 h < 7 days). Membranas biológicas comercialmente disponíveis demonstraram intensa aderência bacteriana e passagem de bactérias, que aumentou durante os períodos experimentais.

Effect of ship-shaped expanded polytetrafluoroethylene nasal prosthesis in rhinoplasty / 中华医学美学美容杂志

Objective:To investigate the effect of ship-shaped expanded polytetrafluoroethylene (e-PTFE) nasal prosthesis in rhinoplasty.Methods:From February 2016 to June 2021, 86 patients, including 9 males and 77 females, aged 18-47 (24±5) years old, were admitted to Chengdu High-tech Zone Xinyuerong Medical Aesthetic Clinic for cosmetic treatment of rhinoplasty. All patients underwent rhinoplasty with the application of ship-shaped e-PTFE and autologous cartilage. The postoperative complications, glabellar fullness, inverted brow triangle, nasal polygon aesthetic shape and patient satisfaction were evaluated. These data were measured and analyzed, including the nasal length, nasal tip height, nasal frontal angle and nasal facial angle before and after the operation.Results:In 86 patients, the incision healed in one stage after surgery, and 8 cases had nasal vestibular scar hyperplasia. All patients were followed up for 1-5 years: 84 cases obtained satisfactory nasal morphology, and 2 cases recovered naturally after adjusting and lowering the prosthesis height half a year after surgery because the interbrow area was too full. 74 patients (86%) were very satisfied, 10 cases (11.6%) were satisfied. The nasal length was (4.07±0.20) cm, the nasal tip height was (2.66±0.36) cm, the nasal frontal angle was (106.42±8.04)°, and the nasal face angle was (15.90±0.85)°before operation. The nasal length was (4.23±0.20) cm, the nasal tip height was (2.59±0.26) cm, the naso-frontal angle was (113.69±6.34)°, and the naso-facial angle was (21.57±0.78)° at eighteen months after operation. There were statistically significant differences in nasal length, naso-frontal angle and naso-facial angle ( t=-5.51, -5.96, -52.31, P<0.01), but no statistically significant differences in nasal tip height ( t=1.47, P=0.146). Conclusions:The ship-shaped e-PTFE can be shaped to reflect the aesthetic of the nose dorsum, which is similar to the anatomical structure of the nose dorsum, increase the stability and authenticity of the prosthesis, and is worthy of clinical application.

Clinical effect of integrated prosthesis on eyebrow arch augmentation / 中华医学美学美容杂志

Objective:To explore the feasibility and advantages of integrated prosthesis of expanded polytetra-fluoroethylene (e-PTFE) in eyebrow arch augmentation.Methods:The clinical data of 45 patients with low or flat brow arch and glabellar zone from June 2019 to October 2020 in Chengdu High-tech Zone Xinyuerong Medical Aesthetic Clinic were analyzed retrospectively, in which it included 45 women, whose ages ranged from 20 to 39 years with average 29.8 years. Forty-three cases underwent primary surgery, and 2 cases underwent repair. The e-PTFE was sculpted to be personalized integrated prosthesis according to the shape of the patient's eyebrow arch and glabellar zone. The incision was designed on the medial and lateral sides of the lower margin of the bilateral eyebrow to avoid the supraorbital foramen, and the lacunae were striped under the frontal periosteum, and the two sides were connected to cover the glabellar zone and inverted triangle area between the eyebrows. The carved e-PTFE was implanted into one side and pulled out from the other side. The prosthesis was smoothed by Venn pliers of the ventral and dorsal sides.Results:The 45 patients in this group were followed up for 6-18 months. The incisions of all the patients were healed Ⅰ/A, and the scar of the incisions was concealed. Slight scalp numbness occurred in 4 patients and returned to normal 3 months later. The prosthesis in the glabellar zone appeared in 1 case 3 months after operation and returned to normal after reoperation. The symmetry, radian, fullness, convexity and tactility of bilateral eyebrow arch were all satisfactory in 45 cases. 39 cases were very satisfied, accounting for 86.7%; 6 cases (13.3%) were satisfactory. The sagittal distance of the anterior surface of the cornea to the soft tissues overlying the supraorbital rims was (2.02±1.72) mm preoperatively and (6.5±1.19) mm in the last follow-up. The difference was statistically significant ( t=14.49, P<0.01). Conclusions:This design of integral e-PTFE in eyebrow arch augmentation is safe, effective and easy to operate. It can significantly increase the bony beauty and stereoscopic sense of the eyebrow arch and glabellar zone, effectively deepen the eye socket, improve the eye protrusion, and reduce the risk of asymmetry and prosthesis displacement, and therefore it is one of the ideal methods for eyebrow arch augmentation.

Fungal infective endocarditis of polytetrafluoroethylene pulmonary valve with Paecilomyces species following tetralogy of Fallot correction

Fungal infective endocarditis of the prosthetic pulmonary valve in non immunocompromised host is growing phenomena attributed to the increased use of prosthetic materials. High mortality and neurovascular sequalae is commonly seen in such case if treatment is delayed. Often misdiagnosed as bacterial endocarditis due to closely resembling clinical features and lack of inexpensive and readily available laboratory tests, the diagnosis is often delayed. High index of suspicion and early surgical intervention is needed for early diagnosis and management

Application of expanded polytetrafluoroethylene in filling nasal base / 中华医学美学美容杂志

Objective To investigate the effect and safety of PTFE filling on correction of nasal basal treatment of midfacial sag.Methods Top of the vestibular sulcus groove was cut along the alveolar mucosa under direct maxillary periosteum,and then face inward in depression and the side line of the scope of subperiosteal separation from near to the medial nasal spine and the lateral side of pyriform aperture;range of separation was the same of both sides as marked before operation,slightly larger than the prosthesis;then the arc being carved,which was consistent with the nasal triangle expansion,was implanted into sub-periosteal site along pear-shaped arc edge of the hole placement and the prosthesis was fixed;as the appearance was satisfied,the incision was sutured.Results Clinical follow-up lasted for 6 months,and all the wound healing was well in primary intention without infection,implant exposure and other complications and facial expressions were natural.The filled results were satisfactory.Conclusions For correction of midfacial depression without need of osteotomy,nasal application of PTFE filling is simple with good efficacy and it is worth promoting.

Preservação do rebordo alveolar com perda óssea vestibular associada a biomaterial e membrana PTFE densa intencionalmente exposta ao meio bucal / Preservation of the alveolar ridge with buccal bone loss associated with biomaterial and d-PTFE membrane intentionally exposed to the buccal environment

O uso de membranas em casos de regeneração óssea guiada tornou-se comum e representa um recurso para ganho de tecido ósseo. As membranas de politetrafluoretileno denso (d-PTFE) são uma opção quando há necessidade de mantê-las expostas ao meio bucal. Neste estudo, relata-se a utilização de uma membrana d-PTFE para regeneração óssea em alvéolo pós-extração em região estética.

The use of membranes in cases of guided bone regeneration has become common and represents a resource for bone tissue gain. Dense polytetrafl uoroethylene (d-PTFE) membranes are an option when there is a need to keep them exposed in the oral cavity. In this study, we report the use of a d-PTFE membrane for bone regeneration in the post-extraction socket in the esthetic zone.

Estandarización de un método por HPLC para cuantificar diclofenaco en muestras de microdiálisis mediante fotoderivatización precolumna / Standardization of a HPLC method for quantitation of diclofenac in microdialysis samples through precolumn photoderivatization

Introducción: la cuantificación del diclofenaco en muestras de pequeño volumen y baja concentración de analito es compleja y requiere de un método analítico sencillo, altamente sensible y reproducible. Objetivo: estandarizar un método por cromatografía líquida de alta resolución (HPLC) con fotoderivatización precolumna, para cuantificar diclofenaco en muestras de pequeño volumen y baja concentración de analito. Métodos: se obtuvieron los fotoproductos del diclofenaco mediante irradiación de muestras a l= 254 nm en celdas de cuarzo, politetrafluoroetileno (PTFE) y polivinilcloruro (PVC), colocadas en diferentes posiciones del área de irradiación durante 6, 24 y 60 min respectivamente. Para la separación de los fotoproductos se utilizó una columna C-18 Agilent Eclipse Plus (5 µm; 150 mm; 4,6 µm id.), usando como fase móvil acetonitrilo (ACN): agua, acidulada con ácido fosfórico hasta pH= 3,0 en diferentes proporciones hasta encontrar la óptima; la temperatura empleada fue de 30 °C, el flujo de 1 mL/min y el volumen de inyección de 20 µL. Se detectaron los fotoproductos por fluorescencia a lambas de excitación y emisión de 286 y 360 nm respectivamente. Resultados: la fotodegradación del diclofenaco en celdas de PTFE ocurrió en 6 min cuando se irradiaron soluciones a 254 nm en el centro del área de irradiación. La separación de los tres fotoproductos principales se logró utilizando una fase móvil ACN: agua, acidulada con ácido fosfórico hasta pH= 3,0; 65:35. El fotoproducto que eluye a 3,4 min se produjo en concentraciones altas y estables las cuales presentaron una tendencia lineal en un gráfico de respuesta del equipo (área) vs. concentración de diclofenaco en un rango entre 1,25-500 ng/mL. Conclusiones: se logró estandarizar un método por HPLC para la cuantificación de diclofenaco presente en muestras de pequeño volumen y baja concentración, el cual podrá someterse a proceso de validación(AU)

Introduction: the diclofenac quantitation in small volume and low analyte concentration samples is complex and requires a simple, highly sensitive and reproducible analytical method. Objective: to standardize a high performance liquid chromatography with precolumn photoderivatization to quantitate diclofenac in small volume and low analyte concentration samples. Methods: diclofenac photoproducts were obtained by irradiating samples at l= 254 nm in quartz polytetrafluoroethylene (PTFE) and polyvinyl chloride (PVC) cells placed in different positions of the irradiation area for 6, 24 and 60 minutes respectively. For the separation of photoproducts, a C-18 Agilent Eclipse Plus column (5 µm, 150 mm; 4.6 µm id.) was used, with a mobile phase containing a mixture of acetonitrile and water pH 3.0 adjusted with ortho-phosphoric acid, in different proportions until the optimal one was found; the flow rate of mobile phase was 1.0 mL/min with column temperature of 30 °C. The sample injection volume was 20 µL. Photoproducts were detected through fluorescence with excitation and emission wavelength at 286 and 360 nm respectively. Results: diclofenac photodegradation in PTFE cells occurs within 6 minutes when solutions are irradiated at 254 nm in the central part of the irradiation area. The separation of the three major photoproducts was accomplished using a mobile phase of acetonitrile: water adjusted with ortho-phosphoric up to pH= 3.0;65:35. The photoproduct at 3.4 minutes was eluted at high stable concentrations, with a linear trend presented in an area graph versus diclofenac concentration in the range of 1.25-500 ng/mL. Conclusions: a new HPLC-method for quantitation of diclofenac in small volume and low concentration samples was standardized; it may undergo validation process(AU)

Autologous nasal septal cartilage combined with expanded-polytetrafluoroethylene in the secondary nasal deformity correction surgery of postoperative cleft lip / 中华医学美学美容杂志

Objective To correct the nasal deformities of cleft lip by expanded-polytetrafluoroe thylene (e-PTFE) combined with autologous nasal septal cartilage.Methods e-PTFE was placed nearby verge of anterior nasal aperture to raise the fundament of nose.Autologous nasal septal cartilage was harvested and combined with e-PTFE to form a sandwich structure.Nasal tip and collapsed nasaI alar were repaired by this method.Results Fifty cases were treated by this method and 42 cases were followed up for about one year.The results were satisfying.The contour of the nose was similar to normal.Only 3 cases were relapsed after one year.Conclusions e-PTFE combined with autologous nasal septal cartilage is an ideal method to correct nasal deformities of cleft lip.

A Case of Hemolytic Anemia Associated with an Inverted Inner Felt Strip on a Proximal Anastomotic Site for Replacement of the Ascending Aorta for Acute Aortic Dissection / 日本心臓血管外科学会雑誌

A 62-year-old man underwent replacement of the ascending aorta for a Stanford type A acute aortic dissection. The proximal stump was reinforced with using internal and external PTFE felt strips, fibrin glue and cellulose fibers. However, hemolytic anemia and hematuria occurred postoperatively. ECG-gated reconstruction CT demonstrated that the hemolytic anemia was induced by collision of red blood cells on the inverted felt strip of the proximal anastomosis. The patient underwent a reparative procedure 1 week subsequent to the initial operation. During reoperation, half of the inner felt strip used for proximal stump fixation was found to be turned up and protruding into the inner lumen. An incision was made in the synthetic graft and the inverting felt material was removed as much as possible, and then a bovine pericardial patch was used as a means of covering the internal felt strip. Here, we report a rare case of hemolytic anemia at the site of an inverted inner PTFE felt strip used for reinforcement of proximal anastomosis. We found that an ECG-gated reconstruction CT is particularly useful in diagnosing this complication around a beating heart.

The Clinical Effect of Micro-Multiporous Expanded Polytetrafluoroethylene Insertion for Recurrent Pterygium

PURPOSE: To investigate the clinical effect of micro-multiporous e-PTFE insertion for severe recurrent pterygium with symblepharon. METHODS: The present study included a total of 13 cases of recurrent pterygium associated with symblepharon, motility restriction and diplopia which had undergone micro-multiporous e-PTFE insertion after pterygium excision, 0.02% mitomycin C application, human amniotic membrane transplantation (AMT) and/or conjunctivo-limbal autograft (CLAU) between September 2010 and February 2011. One month after surgery, the inserted e-PTFE was removed. Recurrence of pterygium and symblepharon, motility restriction, diplopia and injection of ocular surface were evaluated for 11.92 +/- 1.32 months of mean follow-up period. RESULTS: Pterygial recurrence was not observed in 12 out of 13 eyes, and the 1 eye which recurred showed conjunctival recurrence. No postoperative symblepharon recurrence was observed in any of the 13 eyes. Diplopia and motility restriction disappeared in 11 out of 13 eyes, and were improved in the other 2 eyes. VAS (Visual Analogue Scale) injection scores in the wound site decreased after surgery in all patients. CONCLUSIONS: Micro-multiporous e-PTFE insertion combined with mitomycin C application, AMT and CLAU can be a useful surgical method to lower the postoperative recurrence rate and to improve the pterygium-related symptoms in severe recurrent pterygium.

Results of Bypass Surgery in Patients with Atherosclerosis Obliterans of the Lower Extremities / 고신대학교의과대학학술지

OBJECTIVES: This study was performed to study the outcomes of operations in the patients with atherosclerosis obliterans of lower extremities. METHODS: Forty patients underwent vascular bypass operations from January 2006 to December 2010 and were analyzed retrospectively with clinical records. RESULTS: Forty six bypassing procedures were performed in 40 limbs. The type of operations were femoro-popliteal bypass in 29 limbs, femoro-femoral bypass in 15 patiens and popliteo-posterior tibial bypass in 2 limbs. Forty three procedure were done with polytetrafluoroethylene(PTFE) graft and 3 were done with great saphenous vein. The cumulative patency rates of 5years was 58.9% respectively. In two patients, amputations of the lower extremities were done. Reoperations were performed in 9 patients. CONCLUSIONS: A thoughtful management can prevent the progress of atherosclerosis obliterans(ASO) and may preserve the function of lower limb. In this study, bypass surgery using PTFE and great saphenous vein as conduit revealed acceptable patency rate.

Guided bone regeneration using two types of non-resorbable barrier membranes

INTRODUCTION: Guided bone regeneration (GBR) is a common procedure for the treatment of bone defects and bone augmentation. The non-resorbable barriers are well-documented barriers for GBR because of their stability and malleability. However, few GBR studies have focused on the different types of non-resorbable barriers. Therefore, this study examined the clinical results of different non-resorbable barriers for GBR; expanded polytetrafluoroethylene (e-PTFE) (TR-Gore Tex, Flagstaff, AZ, USA), and high-density polytetrafluoroethylene (d-PTFE) (Cytoplast membrane, Oraltronics, Bremen, Germany). MATERIALS AND METHODS: The analysis was performed on patients treated with GBR and implant placement from January 2007 to October 2007 in the department of the Seoul National University Bundang Hospital. The patients were divided into two groups based on the type of non-resorbable barrier used, and the amount of bone regeneration, marginal bone resorption after prosthetics, implant survival rate and surgical complication in both groups were evaluated. RESULTS: The implants in both groups showed high survival rates, and the implant-supported prostheses functioned stably during the follow-up period. During the second surgery of the implant, all horizontal defects were filled with new bone, and there was no significant difference in the amount of vertical bone defect. CONCLUSION: In bone defect areas, GBR with non-resorbable barriers can produce favorable results with adequate postoperative management. There was no significant difference in bone regeneration between e-PTFE and d-PTFE.

Axillary arteriovenous fistula for hemodialysis: case report

Na confecção de fístula arteriovenosa (FAV) para hemodiálise, condutos venosos autógenos demonstram performance superior quando comparados com material protético em relação à perviedade primária ou secundária. A prótese de politetrafluoroetileno (PTFE) é reservada para casos de falência de material autógeno e é geralmente utilizada em fístulas em membros superiores. Descrevemos o caso de uma paciente de 52 anos que, após falência de acessos para hemodiálise e impossibilidade de realização de diálise peritoneal em razão de peritonite bacteriana, foi submetida à confecção de FAV entre a artéria axilar direita e a veia cava inferior com prótese de PTFE de 6 mm. O acesso foi utilizado para hemodiálise 1 mês após sua criação e permanece pérvio após 24 meses. Até o momento, não houve complicações infecciosas, sinais de insuficiência cardíaca ou síndrome de roubo em membro superior direito.

With regards to the creation of an arteriovenous fistula (AV fistula) for hemodialysis, autogenous venous grafts clearly show high performance when compared with prosthetic material in terms of primary or secondary patency. Polytetrafluoroethylene (PTFE) grafts for the reconstruction of AV fistulae must be restricted to cases of failure of the autogenous material, which is generally used in upper limb fistulae. We describe a case of a 52-year-old patient, who, after access failure for hemodialysis and the impossibility of performing peritoneal dialysis due to bacterial peritonitis, underwent the reconstruction of an AV fistula between the right axillary artery and the cava vein using a 6-mm PTFE prosthesis. One month after surgery, this AV fistula started to be used for hemodialysis. The AV fistula remains patent 24 months after its creation. No infectious complications, cardiac insufficiency symptoms, or steal syndromes of right upper limb were detected.

Forehead and Temporal Augmentation with Medium Porosity and High Density ePTFE

In augmentation surgery, one of the important considerations is the selection of artificial implants. Recently, medium-porosity and high-density expanded polytetrafluoroethylene(ePTFE), which has high biocompatibility without gradual loss of volume, has been used as an implant, however, there are not many cases and reports on the post-operative complications and patient satisfactions. Between 2006 and 2009, a total of 23 patients with a flat or depressed forehead/temple underwent augmentation with medium-porosity and high-density ePTFE at our hospital. During follow up periods, 15 patients visited the clinic to fill out a survey and receive a physical examination for any complications, whereas 8 patients underwent a survey on the phone. The patients were asked questions to score their satisfaction rates on a scale of 1 to 10 points. There were no post-operative complications, and, the average score of satisfaction rates on the survey was 8.3 points. Since there were no complications and high rates of satisfaction during follow up periods, this medium-porosity and high- density ePTFE could be considered as a durable implant.

Usefulness of PTFE Graft in Above-Knee Femoropopliteal Artery Bypass

PURPOSE: Which graft material is appropriate for the above-knee femoropopliteal (AK fem-pop) bypass has been a controversy. We were to evaluate the usefulness of PTFE graft in AK fem-pop bypass by comparing the results of autogenous vein graft in below-knee femoropopliteal bypass. METHODS: This was a retrospective study of data for Fem-Pop bypass from August 1999 to August 2008. The median follow-up was 59.9+/-27.3 months. The demographic data, patency rate, secondary procedures, and amputation rate were compared, and statistical comparison was performed by Kaplan-Meier method, Log-rank test, and Chi-square test. RESULTS: Seventy-three bypasses were performed in 63 patients: PTFE graft in 48 cases (Group A), autogenous vein in 25 cases (Group B). Sixty-one patients (96.81%) were men. The mean age was 67.3+/-8.0 years. The indication for surgery was intermittent claudication in 27 cases (37.0%), critical limb in 46 cases (63.0%). The 6-yr primary patency rates were 28.1%; 60.3%, the 6-yr secondary patency rates were 37.2+/-8.4%, 67.0+/-14.7% in Group A and Group B, respectively (P<0.05). The number of secondary procedures was 31 and 3, respectively (P<0.05). Major amputation at later periods was not needed in Group B, but there were 9 cases in group A (P<0.05). CONCLUSION: PTFE graft for above-knee femoropopliteal bypass shows poor long-term patency with a large number of secondary procedures and a higher amputation rate than vein graft in BK Fem-Pop bypass. PTFE graft should be limited to patients with high operative risk, or poor venous graft.

The effect of human demineralized freeze-dried xenograft on vertical bone formation in beagle dogs / 대한치주과학회지

PURPOSE: The purpose of this study was to evaluate exophytically vertical bone formation in the mandibular premolar area of beagle dogs by the concept of guided bone regeneration with a titanium reinforced e-PTFE membrane combined with human demineralized freeze-dried bone. MATERIALS AND METHODS: Four one-year old beagle dogs were divided into control and experimental group. All mandibular premolars were extracted and surgical vertical defects of 5 mm in height were created in the extracted sockets. At 8 weeks after the extraction, TR e-PTFE membrane sized with 8 mm in length, 5 mm in width, and 4 mm in height was placed on the decorticated mandible, fixed with metal pins and covered with full-thickness flap and assigned as control group. In experimental group, decorticated mandibule was treated with TR e-PTFE membrane and human demineralized freeze-dried bone. The animals were sacrificed at 16 weeks after the regenerative surgery, and new bone formation was assessed by histomorphometric as well as statistical analysis. RESULTS: Average of new bone formation was 38% in the control group, whereas was 25% in the experimental group (p<0.05). Average of connective tissue formation was 42% in the experimental group, whereas was 30% in the control group (p<0.05). The lamellar bone formation with haversian canals was observed in the both groups. In the experimental group, the particles of human demineralized freeze-dried bone were observed after 16 weeks and complete resorption of graft was not observed. CONCLUSION: On the basis of these findings, we conclude that titanium reinforced e-PTFE membrane may be used alone for vertical guided bone regeneration, but demineralized freeze-dried bone has no additional effect on vertical guided bone regeneration.

Changes in Polytetrafluoroethylene and Dacron GraftDiameters after Arterial Bypass Surgery

PURPOSE: We compared postoperative diameter changes between polytetrafluoroethylene (PTFE) and Dacron grafts after aortic reconstruction and femoropopliteal bypass. METHOD: We analyzed 173 PTFE grafts and 73 Dacron grafts (165 aortic grafts, 81 peripheral grafts). The mean follow-up period was 28.4 months. RESULT: The mean diameter change in the Dacron grafts (6.6+/-3.0 SD mm) was larger than that in the PTFE grafts (3.7+/-1.8 SD mm). There was a statistically significant difference in the diameter change of PTFE and Dacron aortic grafts (p<0.001). The diameter changes in PTFE peripheral grafts were not significant (p=0.065). There was a significant linear correlation between diameter changes in the Dacron aortic grafts and follow-up duration (correlation coefficient=0.238, p=0.043). Diameter changes in the PTFE grafts showed no linear correlation with follow-up duration, irrespective of grafting range (aortic grafting correlation coefficient=0.048, p=0.646; peripheral grafting correlation coefficient=0.011, p=0.925). CONCLUSION: This study suggests that PTFE has superior durability compared to Dacron, and the change in graft diameter should be taken into consideration when the diameter of the graft needed for aortic reconstruction is selected.

The effect of maintenance period of non-resorbable membrane on bone regeneration in rabbit calvarial defects / 대한치주과학회지

When clinicians faced with an insufficient volume of supporting bone on ideally esthetic and biomechanical position for dental implantation, guided bone regeneration(GBR) was indicated. Although GBR has wide application at clinic, proper time of membrane removal remains qustionable in using non-resorbable membrane, such as non-expanded polytetrafluoroethylene(PTFE). The aim of this study was to compare the effect of maintenance period of PTFE membrane on bone regeneration in rabbit calvarial defects. Eight adult New Zealand white female rabbits were used in this study. Four defects were surgically made in their calvaria. Using a trephine bur, 4 'through and through' defects were created and classified into 3 groups, which were consisted of control group(no graft), experimental group 1(autogenous bone)and experimental group 2(deproteinized bovine bone; OCS-B(R)). The defects were covered with PTFE membrane(Cytoplast(R)). Membranes were removed after 1, 2, 4 and 8 weeks post-GBR procedure in 2 rabbits repectively. All rabbits were sacrificed after 8 week post-GBR procedure. Specimens were harvested and observed histologically. The results were as follow; 1) The use of graft material and membrane was necessary in GBR procedure. 2) When PTFE membranes were removed early, the most favorable bone regeneration was revealed in experimental group I, followed by experimental group II and control group. 3) On GBR, it is recommended that membrane should maintain for 4 weeks with autogenous graft. As well, the use of xenograft need longer maintenance period than autogenous bone. Further evaluations will be needed, such as histomorphologic research, more species and different kinds of graft materials. And on the basis of these studies, clinical researches would be required.

Valor comercial y eficacia de la cinta de politetrafluoretileno (PTFE) para la remoción de la biopelícula dental interproximal comparado con la seda dental de nylon en adolescentes y adultos jóvenes / Price and the efficacy of the polytetrafluoroethylene (PTFE) tape for the removal of the proximal dental biofilm compared to the common nylon dental floss in adolescents and young adults

Objetivo: Identificar el valor comercial y la eficacia de la cinta de politetrafluoretileno (PTFE) como método de higiene oral para la remoción de la biopelícula dental interproximal, comparado con la seda dental de nylon en adolescentes y adultos jóvenes. Métodos: Se utilizó la cinta de PTFE para remover la biopelícula dental interproximal. Por muestreo aleatorio simple el tamaño de la muestra fue de 87 (31 hombres y 56 mujeres) con un rango de edades entre 16 y 28 años. A los participantes se les suspendió toda clase de higiene oral durante un período de 12 horas, posteriormente se realizó una tinción con revelador de placa bacteriana y se llevó a cabo la remoción tanto con la cinta de PTFE como con la seda dental mediante la misma técnica y por el mismo operador. La recolección de datos se hizo con base en la división coronal (por tercios) del índice de higiene de Greene y Vermillion, pero se modificó para evaluar solamente las caras interproximales. Resultados: En el grupo de seda dental la presencia de la biopelícula dental interproximal fue 72.6% antes y 11.2% después de la remoción y en el grupo de PTFE fue 72.9% antes y 11% después; al comparar la remoción de la biopelícula con los dos métodos no hubo diferencias estadísticamente significativas (p>0.05). El valor comercial del PTFE es en promedio 2.7 veces más económico que el de la seda dental de nylon. Conclusiones: La similitud en la remoción de la bio-película interproximal de la cinta de PTFE frente a la seda dental fue significativa. Gracias a su buena bio-compatibilidad, tolerancia y bajo costo, la cinta de PTFE sirve como un método alternativo para retirar la bio-película interproximal. Los resultados de este estudio abren una puerta para investigar técnicas poco ortodoxas, pero eficaces, en el mantenimiento de la salud bucal con el único propósito de mejorar la calidad de vida en las poblaciones menos favorecidas.

Objective: To identify the price and the efficacy of the polytetrafluoroethylene PTFE tape as an oral hygiene method for the removal of the proximal dental biofilm, compared to the common nylon dental floss in adolescents and young adults. Methods: The polytetrafluoroethylene tape was used as a method for the removal of the proximal dental biofilm. By a randomized procedure the sample size was of 87 (31 men and 56 women) between 16 and 28 years old. The oral hygiene of the participants was suspended during a period of 12 hours. A suitable disclosing solution was used to paint the dental surfaces. The removal of the biofilm was made by the same operator who used the same technique with the two materials (polytetrafluoroethylene tape and nylon dental floss). The information was collected using the coronal division (in thirds) of the Greene and Vermillion Oral Hygiene Index. This index was modified to evaluate proximal surfaces only. Results: In the group of dental floss the presence of the proximal biofilm was 72.6% before and 11.2% after its removal. In the group of PTFE was 72.9% before and 11% after. After the comparison of the two methods the differences are not significant. PTFE price is 2.7 times lower than common nylon dental floss. Conclusions: The similarity in the removal of the proximal biofilm of the PTFE tape when compared to the nylon floss was significant. Thanks to its biocompatibility, tolerance and its low price, the PTFE tape is an alternative method for the removal of the biofilm in these proximal areas. Results of this study open a way for the investigation on non orthodox techniques, but effective, for the maintenance of the oral health with the only purpose of improving life quality of poor populations.

Surgical Treatment of Infected Prosthetic Dialysis Arteriovenous Graft

PURPOSE: Hemoaccess using a polytetraflouroethylene (PTFE) graft is widely performed when primary arteriovenous access is unavailable. An infection of a PTFE graft is a common complication and a major cause of hemoaccess failure. This study reviewed the infected case of PTFE grafts in our hospital, and evaluated the incidence, surgical treatment, progress and outcome. METHODS: From March 2000 to February 2005, among 1,067 patients who received PTFE graft surgery in Soonchunhyang University Hospital, 58 patients were treated graft infection. These patients were managed by a total graft excision (TGE), a subtotal graft excision (SEG), and a partial graft excision (PEG) with a bypass graft. Usually, SGE is defined as the removal of all of the graft except for 2~3 mm from the arterial anastomosis. However, in our cases, SGE was performed with 1~1.5 cm of the arterial remnants, according to the operative risk, and either the surgical technique or the patient's medical condition. All the records were reviewed retrospectively. RESULTS: The mean age of the patients was 55 years, and 36 patients had a history of diabetes. The PTFE graft placed in the brachiobrachial position of the upper arm was encountered most frequently (72%). 23 graft infections located within the body of the graft, 20 of these were documented to be at a recent puncture site for hemodialysis access. The most common presentation (29%) was purulent discharge. Among the 58 patients treated for a graft infection, 40 patients received SGE, PGE was replaced by a new graft in 15 patients, TGE was performed in 2 patients, and incision and drainage was performed in 1 patient. After surgery, all the patients were treated with antibiotics. The bacterial cultures were positive in 38 cases. Of the 38 culture positive wounds, the most common organism was Staphylococcus aureus (33 cases). 15 cases developed infectious complications: pneumonia, systemic sepsis, duodenal ulcer with or without bleeding, and septic arthritis. The overall mortality was 8% (5 patients). Among the SGE patients, 11 patients evolved an infection of the remnant prosthesis, and a surgical procedure was required. CONCLUSION: Infections are one of a serious complications of PTFE graft that can progress more graft failure or death. There are many treatment options. These include 1) Incision and drainage, 2) TGE, 3) SGE and 4) PGE. TGE should be performed if the graft is not well incorporated or the entire graft was infected. In our experience with infected peripheral bypass grafts, a subtotal graft excision was used if the arterial anastomosis was intact and encased in scar tissue. A risky dissection of an artery encased in scar tissue was avoided by oversewing 1~1.5 cm rather than a 2~3 mm cuff of the remainder of the graft.