***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND This retrospective study was set to assess the influence of systemic and local bone and intra-oral factors on the occurrence of implant loss from abutment connection up to 2 years . MATERIAL S AND METHODS The files of 700 patients , have been collected r and omly from the total patient group treated by means of endosseous Brånemark system implants ( Nobel Biocare , Gothenburg , Sweden ) at the Department of Periodontology of the University Hospital of the Catholic University of Leuven . The end point observation was evaluating the loss of the implants 2 years after abutment installation . The study involved all implants that did not encounter early loss and implants for which it was possible to evaluate its status 2 years after abutment surgery . Thus , data of 412 patients ( 240 females ) provided with 1514 implants were analyzed . For each patient , the medical history was carefully checked . Data collection and analysis were mainly focused on endogenous factors such as hypertension , coagulation problems , osteoporosis , hypo- hyperthyroidism , chemotherapy , diabetes type I or II , Crohn 's disease , some local factors [ e.g. bone quality and quantity , implant ( length , diameter , location ) , type of edentulism , PTV , radiotherapy ] , smoking habits , and breach of sterility during surgery . RESULTS Radiotherapy , implant ( diameter and location ) , and higher PTV at implant insertion and abutment connection , all affected significantly the implant loss . CONCLUSION Implant location in the oral cavity and radiotherapy seem predominant to explain the occurrence of implant loss . On the other h and , smoking and systemic health factors do not seem to be prominent players in the etiology of late implant loss PURPOSE Achieving primary implant stability in areas with poor bone density is often challenging to the clinician . Previous research has suggested that modified surgical protocol s might be beneficial in such situations . The objective of the present clinical study was to evaluate the survival rate of implants placed using undersized implant site preparation in areas with poor bone density . MATERIAL S AND METHODS A total of 52 implants were placed in 29 patients . Of the 52 implants , 26 were surgically placed according to the st and ard drilling protocol ( control group ) and 26 were placed in low-density bone using an adapted bone drilling method ( test group ) . The maximum insertion torque values and resonance frequency analysis measurements were also recorded . All implants were examined clinical ly and radiographically at follow-up visits during the study period . Oral hygiene status , bleeding on probing , peri-implant probing depth , and implant survival rate were assessed . RESULTS According to the survival criteria used in the present study , no failure was recorded , and the overall survival rate was 100 % for both groups after 12 months . The mean probing depth was 2.75 ± 0.75 mm in the test group and 2.87 ± 0.79 mm in the control group . The mean insertion torque value was 35.19 ± 4.79 Ncm in the test group and 34.62 ± 5.82 Ncm in the control group . The resonance frequency analysis value was 68.58 ± 4.81 implant stability quotient and 66.69 ± 5.41 implant stability quotient in the test and control groups , respectively . The observed differences were not statistically significant ( P > .05 ) . CONCLUSIONS The results of the present study suggest that placement of implants by an adapted drilling technique in sites with poor bone density is beneficial in enhancing primary implant stability and improving the implant survival rate BACKGROUND The survival rate of oral implants  in soft- quality bone has been demonstrated to be inferior to that of implants inserted in good- quality bone . A possible way to increase the survival rate in soft- quality bone may be to use a tapered implant . Such an implant has been developed and manufactured by Nobel Biocare AB , Gothenburg , Sweden . So far , there have been only a few publications regarding this implant . PURPOSE The aim of the study was to compare the outcome of using the tapered Brånemark System Mark IV fixture with the outcome of using earlier Brånemark fixtures in a controlled prospect i ve study . MATERIAL S AND METHODS The study was performed as a multicenter study including seven specialist centers . The material consisted of 40 patients in need of implant-supported bridges in the maxilla . Twenty-five patients belonged to the test group , in which the tapered Mark IV implants were inserted , and 15 patients belonged to the control group , in which Brånemark St and ard or Mark II implants were used . The patients were allocated to the test group or the control group according to r and omization schedules . The implants were inserted according to the guidelines for Brånemark implants . A two-stage surgical protocol was used , and abutment connection was made 6 months after fixture insertion . The test group comprised 97 Mark IV implants  , and the control group made up 92 implants .  The prosthetic procedure followed the guidelines for Brånemark implants , and all patients were provided with full fixed maxillary bridges . The patients were followed up with clinical and radiographic records for 1 year after loading . RESULTS The survival rate was 96.9 % for the Mark IV implants and 98.9 % for the control implants . There was no significant difference between the two groups . There was a mean marginal bone loss of 0.2 mm during the observation period , and there was no difference between test implants and control implants . CONCLUSIONS With regard to survival rate and marginal bone level changes , no differences could be demonstrated between the Mark IV tapered implant and the Brånemark implants used earlier . However , compared with earlier results of Brånemark implants in soft- quality bone , the Mark IV implant demonstrated an improved survival rate BACKGROUND Osteoporosis has been called a potential risk factor for bone healing around implants . AIM The aim of this multicentre study was to verify the clinical performance of fluori date d implants in the maxilla of subjects with diagnosed systemic primary osteoporosis/osteopenia . MATERIAL AND METHODS Postmenopausal women in need of 2 - 8 splinted implants in maxilla underwent bone mineral density measurements in the hip and spine , using dual-energy X-ray absorptiometry scans . Based on their T-scores , they were divided into two study groups : Group O ( osteoporosis/osteopenia group ) subjects had a T-score ≤-2 , Group C ( control group ) had a T-score of ≥-1 , and subjects with a T-score < -1 but > -2 were excluded .  Implants were placed with a two-stage procedure and loaded 4 - 8 weeks after abutment surgery . At 6 months and 1 year after functional loading , clinical parameters ( including peri-apical radiographs ) were assessed . RESULTS One hundred and forty-eight implants were placed in 48 subjects ( mean age : 67 years ( range [ 59 - 83 ] ) . Sixty-three implants were placed in 20 osteoporosis subjects ( Group O , mean age : 69 years ; range [ 59 - 83 ] ) , and 85 were placed in control subjects ( Group C , mean age : 65 years ; range [ 60 - 74 ] ) . The cumulative survival rate , on an implant level , was 99.3 % ( Group O : 98.4 % ; Group C : 100.0 % ) . The cumulative survival rate , on a subject level , was 97.9 % ( Group O : 94.7 % ; Group C : 100.0 % ) . Marginal bone level ( MBL ) alterations from functional loading to the 1-year follow-up visit were measured on an implant level and a subject level . The overall MBL alteration on an implant level was -0.01 ± 0.51 mm ( Group O : -0.11 ± 0.49 mm ; Group C : 0.05 ± 0.52 mm ) . The overall MBL alteration on a subject level was -0.04 ± 0.27 mm ( Group O : -0.17 ± 0.30 mm ; Group C : 0.04 ± 0.23 mm ) . CONCLUSION Within the limitations of this prospect i ve , non-r and omized , controlled , multicentre study , it can be concluded that oral implant therapy in patients suffering from osteoporosis/osteopenia is a reliable treatment option with comparable integration rates as in healthy patients . Long-term follow of the study groups is necessary to compare marginal bone alterations and treatment outcomes AIM This study aim ed to assess the influence of systemic and local bone and intra-oral factors on the occurrence of early TiUnite implant failures . MATERIAL AND METHODS A total of 283 consecutive patients ( 187 females ; mean age 56.2 ) , who received a total of 720 TiUnite implants , at the Department of Periodontology of the University Hospital of the Catholic University of Leuven , were prospect ively followed . The following aspects were particularly assessed : hypertension , cardiac problems , gastric problems , osteoporosis , hypo- or hyperthyroid , hypercholesterolaemia , asthma , diabetes types I or II , Crohn 's disease , rheumatoid arthritis , chemotherapy , hysterectomy and intake of medication ( antidepressants , steroids , hormone replacement ) , radiotherapy of the concerned area , breach of sterility during surgery , implant parameters , bone ( quality , quantity , dehiscence or perforation ) , type of edentulism , antibiotics prescription , fenestration of the implant in the sinus/nasal cavity , immediate implant placement , apical lesion detection and insertion torque . RESULTS AND CONCLUSION A global failure rate of 1.9 % was recorded . Owing to the very few failures , no definitive conclusion concerning statistical significance can be achieved . However , a tendency for more failures was noticed for apical lesions , vicinity with natural dentition , smoking , hormone replacement , gastric problems , Crohn 's disease , diabetes I and radical hysterectomy PURPOSE This prospect i ve clinical study evaluated the performance of 290 tapered , anodic oxidized ( TiUnite ) titanium implants placed in compromised bone in a consecutive series of 126 patients . MATERIAL S AND METHODS Inclusion criteria were : ( 1 ) a need for dental implants in either a single-tooth or partially edentulous segment , ( 2 ) sufficient medical fitness to undergo the procedure , ( 3 ) enough bone to enable placement of a 10-mm or longer implant , and ( 4 ) compromised bone , as judged by computerized tomography and confirmed by clinical findings , in at least one implant site .  Implants were placed and left unloaded for at least 6 months ( mean 9.9 + /- 3.9 months ) before placement of the first provisional prosthesis and followed for at least 3 years after loading . Marginal bone was measured by an independent radiologist . RESULTS A second-stage uncovering was required for approximately half the implants . Failure of osseointegration was observed for only two implants ; all other implants provided the intended prosthetic support during the entire observation period . The overall implant survival rate after 3 years of loading was 99.3 % . The average mean changes in the marginal bone level showed stability ( -2.70 mm , -2.67 mm , and -2.74 mm at 1 , 2 , and 3 years postloading , respectively ) . CONCLUSIONS Using a modified surgical technique that minimized the osteotomy dimensions , tapered implants with an oxidized surface proved to be a predictable support for fixed prostheses in both grafted and ungrafted compromised bone . Marginal bone levels were stable throughout at least 3 years of follow-up AIM To assess the failure and bone-to-implant contact rate of  dental implants placed on osteoporotic subjects . METHODS Extensive examination strategies were created to classify studies for this systematic review . MEDLINE ( via PubMed ) and EMBASE data base were examined for studies in English up to and including May 2014 . The examination presented a combination of the MeSH words described as follow : " osteoporosis " or " osteopenia " or " estrogen deficiency " AND " implant " or " dental implant " or " osseointegration " . Assessment of clinical and /or histological peri-implant conditions in osteoporosis subjects treated with titanium dental implants . The examination included a combination of the MeSH terms described as follow : " osteoporosis " or " osteopenia " or " estrogen deficiency " AND " implant " or " dental implant " or " osseointegration " . RESULTS Of 943 potentially eligible articles , 12 were included in the study . A total of 133 subjects with osteoporosis , 73 subjects diagnosed with osteopenia and 708 healthy subjects were assessed in this systematic review . In these subjects were installed 367 , 205 , 2981 dental implants in osteoporotic , osteopenic and healthy subjects , respectively . The failure rate of dental implant was 10.9 % in osteoporotic subjects , 8.29 % in osteopenic and 11.43 % in healthy ones . Bone-to-implant contact obtained from retrieved implants ranged between 49.96 % to 47.84 % , for osteoporosis and non-osteoporotic subjects . CONCLUSION Osteoporotic subjects presented higher rates of implant loss , however , there is a lower evidence to strengthen or refute the hypothesis that osteoporosis may have detrimental effects on bone healing . Consequently , final conclusions regarding the effect of o 
    Output:
    
The meta‐ analysis showed no significant difference between implant survival in patients with low and normal bone density 5 years after implant placement .
Conclusions .
Implant survival in patients with low bone density seems to be feasible with special pre caution s. Implant placement using special adopted techniques might provide equivalent implant stability , survival , and marginal bone loss to normal bone .