THE CE ANSWER SHEET APPEARS ON PAGE 37 based on the origin of the donor material: autografts, allografts, allo- plasts, and xenografts.3 Autografts and allografts are associated with human donors. An autograft is tissue taken from and placed in the same individual. These have the highest potential for success because the tissue is obtained from the recipient. Unfortunately, this is not always an option, leaving an allograft as the next option. Allografts are retrieved from a donor and placed in a different individual of the same species. They typically consist of tissue that is taken from a cadaver. Similar to the autograft, allograft studies have shown high success rates and enhanced tissue growth.3 Alloplasts are synthetic tissue substitutes made of nonvital materials. They offer a support system for surrounding structures and encourage tissue to grow around them, but they do not contain factors for cells to induce bone (unlike a tissue-derived graft). Alloplasts carry no risk of disease transmission and the patient does not have to undergo addi- tional procedures to collect donor tissue. Xenografts are tissue substi- tutes taken from a different species, such as bovine.3 Because L-PRF is an autologous biologic modifier obtained from the patient’s blood, it provides a condensed network of fibrin that is satu- rated with cytokines, growth factors and platelets.4 In short, it speeds up the initial healing process of tissue repair and is capable of generat- ing soft tissue and bone; L-PRF can be used alone or in conjunction with a bone substitute. There are many circumstances in which tissue growth needs to be supported for the success of a procedure. PROCEDURAL STEPS An L-PRF procedure is relatively simple and begins with a blood draw. Approximately 9 to 10 ml of blood is drawn with a 24-gauge butterfly needle and placed in a glass tube.2 clot polymerization.5 The glass tube is needed to achieve Correct handling of the blood is a significant fac- tor in L-PRF treatment success. The blood must be immediately trans- ferred to a centrifuge, which is activated for approximately 12 minutes, without the addition of an anticoagulant.6,7 During the centrifuge process, the blood coagulates and separates into three layers. Com- posed of red blood cells, the bottom layer is discarded. The top layer is cell-free and is also discarded. The middle layer is a mesh network that contains the majority of the platelets and fibrin. Within this middle layer, platelets lead to synthesizing growth factors in response to clot- ting.8 The fibrous middle layer also acts as a scaffold when placed for surgical dental treatment, leading to the initiation of tissue response.9 This layer can be compressed into a membrane or shaped into a plug, depending on the treatment needed. This clot can be converted into a membrane by compression between two sterile gauzes or by using a specific tool for collection.1 The fibrin is easily manipulated and placed, allowing it to be used with many dental treatment options. Once placed, the L-PRF continues to release growth factors for up to seven days, which speeds up healing time. The cost for this proce- dure is lower than other options for patients because fewer materials are needed and the patient supplies his or her own blood for the pro- cedure. Additionally, because the tissue (i.e., blood) is taken from the patient, its use reduces the risk of infection and disease transmission, which diminishes the chance of rejection. DecisionsInDentistry.com APPLICATIONS AND RESEARCH The L-PRF technique has numerous clinical applications, including soft tissue and bone regeneration, extraction socket and alveolar ridge preservation,6 ment of three-wall infrabony defects,10 placement,2 tion defects,12 periodontal tissue regeneration,11 assisting with repair of mandibular fracture sites,8 horizontal and vertical ridge augmentation, improve- sinus lift procedures for implant improvement of furca- and stimulation of enhanced repair when used in combination with bone substitute or autologous bone.13–15 Temmerman et al6 conducted a case study to determine the success conducted a study with 15 patients that analyzed the placement of L-PRF in an extraction site while simultaneously plac- ing an implant. Similar to other studies, each patient rinsed with chlorhexidine gluconate prior to the procedure. A flap was reflected and the tooth extracted. The socket was then irrigated and curetted thoroughly. Each site for implant insertion was continuously irrigated while being drilled to necessary dimensions based on implant size. Implants were inserted 2 to 3 mm beyond the original apex level to aid in stability. Following this, the space left between the socket wall and implant was packed with deproteinized bovine bone material, and an L-PRF membrane positioned and sutured in place.16 JOSEPH W. EVANS, DDS, is an associate professor of dental hygiene at Western Kentucky University in Bowling Green. He has worked in private practice and public health, and his research interests include forensic dentistry, sports dentistry, dental radiology and abnormalities of the developing dentition. He can be reached at [email protected]. KYNDALL A. HUDSON, RDH, is a dental hygienist in a Brentwood, Tennessee, private practice. The authors have no commercial conflicts of interest to disclose. December 2017 • Decisions IN DENTISTRY 41 of placing L-PRF in an extraction site to aid in alveolar ridge preserva- tion. The study included 22 subjects who were monitored after extrac- tions. It utilized a split-mouth randomized controlled clinical approach that compared a control group using no membrane in the extraction sites with sites undergoing the L-PRF membrane. Alveolar ridge levels of the extraction sites were compared using cone beam computed tomography. Each tooth was extracted and blood drawn to be cen- trifuged. The L-PRF membrane was isolated, compressed, and placed in the extraction sites with subsequent suturing. Patients were pre- scribed a 0.12% chlorhexidine spray for use twice a day and seen seven days later to monitor healing and remove sutures.6 At the follow-up appointment, patients reported discomfort follow- ing the procedure. The majority of extraction sites revealed a healing site that showed no signs of abnormality. Cone beam computed tomo- grams were taken immediately after the extraction and three months after treatment to track the progress. These images were then super- imposed to analyze the measurement of alveolar ridge present imme- diately after the extraction and at the three-month follow-up visit. Data showed that the sites where L-PRF was placed had a statistically higher success rate than those sites without. The researchers found a strong statistical correlation associated with the placement of L-PRF in extrac- tions sites with improved healing when compared to those without.6 El Kenawy et al16
