patients with hematologic disorders are at a greater risk for prolonged bleeding ; therefore , it is important to reduce opportunities for bleeding during surgical implant procedures . prolonged bleeding can interfere with the initial process of osseointegration , and recurrent bleeding from a wound site leads to persistence of iron in the tissue . excessive tissue iron is associated with fibrosis , poor wound healing , and excessive angiogenesis1 . if bone apposition does not occur , fibrous - scar tissue is formed between the implant surface and the surrounding bone2 , which results in the absence of an anchoring function of the endosseous implant . additionally , a lack of white blood cells ( wbcs ) increases the amount of oral pathologic organisms , which might play a role as an etiological factor in late implant complications . aplastic anemia is a rare hematological disease characterized by pancytopenia and bone marrow hypoplasia , where normal hematopoietic tissue is replaced by fatty tissue . the incidence rate of aplastic anemia is two per one million persons per year , as reported by young3 . though the etiology of aplastic anemia is typically unknown , it can be inherited , idiopathic , or acquired . acquired aplastic anemia can be caused by intake of certain drugs and chemicals45 , radiation therapy6 , viral infection78 , or pregnancy . this characterization indicates that the immune system attacks the bone marrow , resulting in insufficient blood cell production . patients that suffer from aplastic anemia complain of general fatigue , shortness of breath , and pale appearance due to low red blood cell ( rbc ) count . in addition , thrombocytopenia increases the risk of severe bleeding at various sites and is associated with oral manifestations such as petechia , ecchymosis , hematoma , gingival bleeding , and bleeding after tooth extraction9 . in patients with severe aplastic anemia , infection and bleeding can be life threatening , and such patients have demonstrated a high mortality rate . although patients with moderate aplastic anemia might not require treatment , frequent and regular blood cell counting is important . recent therapeutic advances , such as immunosuppressive therapy with bone marrow transplantation , use of growth factor alone or in conjunction with immunesuppressive therapy after bone marrow transplantation , blood component transfusion , and improved infection control , have increased survival rates1011 of such patients . this study evaluated the following parameters ; 1 ) the amount of peri - implant bone resorption , 2 ) level of osseointegration as measured by the amount of fine trabecular bone in close contact with the fixture , 3 ) probing depth , and 4 ) periabutment gingival connective tissue contour . the purpose of this study was to demonstrate the effectiveness of implant - supported restoration in aplastic anemic patients by evaluating radiographic and clinical features . a 44-year - old woman presented to the department of oral and maxillofacial surgery of chonnam national university hospital ( gwangju , korea ) to evaluate missing teeth in the maxilla and the mandible and possible implant - supported restoration . the patient had been diagnosed with severe aplastic anemia at the department of hemato - oncology of chonnam national university hospital in july 1995 and had received immunosuppressive therapy . she has been under regular follow - up and had taken 1 mg of folin ( folic acid ) and 50 mg of pyridoxine ( vitamin b6 ) from may 2004 to june 2005 . a general assessment was performed based on panoramic radiograph and cone - beam computed tomography , and we planned to install 14 endosseous implants . ten implants were inserted in the mandible in the first stage , and four implants were inserted in the maxilla in the second stage , with elevation of both sinuses and autogenous bone grafts . during the preoperative evaluation , the department of hemato - oncology confirmed that the patient would be able to maintain a greater than 1,000 absolute neutrophil count and have lower chances of postoperative bleeding if she was able to maintain a greater than 80,000 platelet count during the surgery . a complete blood cell count investigation revealed that the patient had an rbc of 3.51 million , a wbc count of 3,000 , and a count of 84,000 platelets per milliliter of blood . these results indicated that both extraction of teeth # 17 , # 16 , # 26 , and # 27 with poor prognosis and implant surgery could be performed without any special consideration . after five months of healing , the full mucoperiosteal flap was elevated with a midcrestal incision and two vertical releasing incisions under intravenous sedation with midazolam ( 0.05 mg / kg ) and the local anesthesia lidocaine plus with epinephrine 1:100,000 . ten osstem us ii ( osstem implant co. , busan , korea ) implants were installed in the spaces left by teeth # 32 , # 33 , # 34 , # 36 , # 37 , # 42 , # 43 , # 44 , # 46 , and # 47 ( fig . a ) , and then provisional implants were placed in the sockets of teeth # 31 , # 35 , # 41 , # 45.(fig . d ) primary closure of the flap involved periosteal releasing incisions , and 3 - 0 vicryl ( ethicon inc . , cornelia , ga , usa ) was used as suture material . three months after implant installation , a second surgery was performed with an apically repositioned flap in order to produce keratinized gingiva , which helps maintain a healthier gingival environment.(fig . b ) four months postoperatively , the provisional prostheses were replaced with the final prostheses.(fig . c ) we obtained panoramic radiographs using the kodak 8000c system ( carestream health inc . , atlanta , ga , usa ) and evaluated all panoramic and periapical radiographs with piview star ( infinitt healthcare co. , ltd . , seoul , korea ) . marginal bone change was estimated from the border between the implant platform and implant abutment to the lowermost part of the absorbed marginal bone around the implant fixture , based on radiographs performed immediately after the operation . the magnification ratio on the radiographs was corrected by comparing the actual length of an implant fixture with that on the radiographic image . after two months of loading on the final mandible prostheses , bilateral sinus elevation was performed with ramal bone graft . the oval - shaped bony windows were removed from the lateral walls of the sinuses , and sinus membranes were carefully elevated , followed by bone grafting . particulated ramal bone graft material was used in combination with bio - oss ( geistlich pharma ag , wolhusen , switzerland ) , and four osstem us ii implants were simultaneously placed at sites # 16 , # 17 , # 26 , and # 27.(fig . e ) fibrin glue was injected into the bone graft site to enhance the bone healing process . all of the procedures were performed under intravenous sedation and local anesthesia with a vasoconstrictor , and the medications were the same as listed above . seven months after implant installation in the sinus elevation site , prosthetic loading was applied , and peri - implant bone change was evaluated in panoramic and periapical radiographs . after one year and three months of prosthetic loading on the lower jaw , marginal bone change was evaluated around the implants using panoramic and periapical radiographs ( fig . f ) , which revealed peri - implant bone resorption of 1.37 mm on # 16 , 1.73 mm on # 17 , 1.30 mm on # 26 , 1.11 mm on # 27 , 1.32 mm on # 32 , 1.70 mm on # 33 , 1.89 mm on # 34 , 1.0 mm on # 36 , 0.86 mm on # 37 , 0.50 mm on # 42 , 0.72 mm on # 43 , 1.0 mm on # 44 , 2.52 mm on # 46 , and 2.12 mm on # 47 . tranexamic acid at a concentration of 500 mg/5 ml was available for perioperative bleeding . however , no severe bleeding occurred intraoperatively or postoperatively , and no postoperative complications were noted . on follow - up , the marginal bone had not changed significantly one year and three months after prosthetic loading . in periapical radiographs , fine trabecular bone was observed around each fixture , which indicates that osseointegration was successful for all of the implants . we measured the probing depth , which is the distance from the gingival margin to the periodontal pocket , on the mesiobuccal and distobuccal sides of each tooth . the average of the measured values for each tooth was calculated , and a mean probing depth of 1.66 mm was obtained using the williams colorvue probekit ( hu - friedy , chicago , il , usa ) . all procedures , from surgery to restoration , were uneventful over a follow - up period of seven years.(fig . f ) no implants showed mobility , and the patient did not complain of pain or discomfort during the seven - year follow - up period . in addition , there was no evidence of peri - implant radiolucency seven years after implant installation . finally , only two implants ( # 46 , # 47 ) showed marginal bone resorption greater than 2 mm after seven years of follow - up . implant - supported restoration has become common practice in dentistry and is associated with long - term successful outcomes . this could increase the popularity of implant - supported restoration among dentists and the general public even though its effect in medically compromised patients , especially those with bleeding disorders , has not been thoroughly demonstrated . special considerations for these medically compromised patients include bleeding control during operative and postoperative periods in order to avoid life - threatening situations , achieving successful osseointegration , and long - term implant maintenance . an extended period of adequate hemostatic function is necessary to accommodate the normal healing process , probably because the risk of hemorrhage is increased by vascular remodeling and angiogenesis during the healing process12 . furthermore , patients with aplastic anemia are susceptible to peri - implant infection as aplastic anemia is characterized by marked hypoplastic bone marrow and pancytopenia ( anemia , leucopenia , and thrombocytopenia ) . we were not able to collect data regarding specific blood management strategies for successful implant placement in cases of aplastic anemia , so we followed the general guidelines . we prepared a blood transfusion to maintain platelet count during surgery , since a platelet count less than 25,000/ml indicates a high risk of spontaneous oral bleeding9 . tranexamic acid was also prepared for prolonged retention of intact weak blood clots and to prevent bleeding in plasminrich areas such as the oral cavity . tranexamic acid can significantly reduce blood loss after oral surgery in patients with hemophilia and can be used topically or systemically13 . radiographic examinations with implant mobility tests are the most reliable for assessing osseointegration . although two of the present implants showed moderate peri - implant bone resorption , observed while loading dental prostheses , other implants were well - maintained , fulfilling the success criteria cited by albrektsson et al.14 . the first two implants were categorized into group ii ( satisfactory survival ) , and the others into group i ( success , optimum health ) , according to the health scale developed by the international congress of oral implantologists consensus conference for implant success in pisa in 200715 . fine trabecular bone structure was observed around all of the implant fixtures , which created sufficient anchorage necessary for long - term implant maintenance . stable , rigid , fixated implants have been reported with pocket depths ranging from 2 to 6 mm15 ; in the presented case , the mean probing depth was 1.66 mm after 21.4 months of prosthetic loading . thus , based on these results , implant surgery can be performed safely even for patients with hematologic disorders by applying three principles of implant installation ; induction of initial hemostasis , maintenance of hemostasis during the healing period , and immobilization of the implant . these can be achieved through appropriate systemic treatment and precise management of local soft tissue .
the purpose of this study was to investigate implant - supported restoration as a technique for restoring missing teeth in patients with aplastic anemia . 
 recurrent bleeding from wound sites leads to persistent release of iron in the tissue . 
 excessive iron in tissue is related to clinical findings , including fibrosis , poor wound healing , and high level of angiogenesis , which are possible etiological factors of reduced osseointegration . 
 a 44-year - old female patient with aplastic anemia was treated with multiple endosseous implants throughout the mandible and in the posterior region of the maxilla . 
 after 14 implants were placed , radiological and clinical parameters were assessed during the follow - up period . 
 marginal bone did not change significantly during the follow - up period . the fine trabecular bone in intimate contact and enclosing the implant fixture was sufficient for successful osseointegration . 
 none of the 14 implants were associated with compilations during the seven - year experimental period . 
 this study suggests that dental implant procedures are a safe and reliable treatment option for restoration of missing dentition in patients with aplastic anemia .