***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: The McGill consensus statement on overdentures ( 14 ) was published following a symposium held at McGill University in Montreal , Canada in 2002 . A panel of relevant experts in the field stated that : The evidence currently available suggests that the restoration of the edentulous m and ible with a conventional denture is no longer the most appropriate first choice prosthodontic treatment . There is now overwhelming evidence that a two-implant overdenture should become the first choice of treatment for the edentulous m and ible ( 14 ) . In 2009 , a further consensus statement was released as a support and follow-up to the McGill consensus statement . This report was jointly created by members of the BSSPD ( British Society for the Study of Prosthetic Dentistry ) Council and the panel of presenters at the BSSPD conference in York , UK in April 2009 ( 15 ) . This report also highlighted that since the McGill statement in 2002 , uptake by dentists of implant technology for complete denture wearers has been slow . The York statement concluded that ' a substantial body of evidence is now available demonstrating that patients ' satisfaction and quality of life with ISOD m and ibular overdentures is significantly greater than for conventional dentures . Much of this data comes from r and omised controlled trials ( 15 ) . Whilst it is accepted that the two-implant overdenture is not the gold st and ard of implant therapy it is the minimum st and ard that should be sufficient for most people , taking into account performance , patient satisfaction , cost and clinical time The aim of this study was to evaluate the effect of platelet-rich plasma ( PRP ) on remodeling of autologous bone grafts used for augmentation of the floor of the maxillary sinus . In five edentulous patients suffering from insufficient retention of their upper denture related to a severely resorbed maxilla , the floor of both maxillary sinus was augmented with an autologous bone graft from the iliac crest . R and omly , PRP was added to the bone graft used to augment the floor of the left or right sinus ( split-mouth design ) . Three months after the reconstruction , bone biopsies were taken with a trephine from the planned implant sites ( N=30 ) . Subsequently , three implants were placed in the left and right posterior maxilla . Microradiograms were made of all biopsies ( N=30 ) , whereafter the biopsies were processed for light microscopic examination . In addition , clinical parameters were scored . Wound healing was uneventful , clinical ly no difference was observed between the side treated with PRP or not . Also microradiographical and histomorphological examination of the biopsies revealed no statistical difference between the PRP- and non-PRP side . One implant placed in the PRP side of the graft was lost during the healing phase . Implant-retained overdentures were fabricated 6 months after implantation . All patients functioned well ( follow-up 20.2+/-4.3 months ) . In this study , no beneficial effect of PRP on wound healing and bone remodeling was observed . It is posed that PRP has no additional value in promoting healing of grafted non-critical size defects PURPOSE The aim of this systematic review is to address treatment outcomes of M and ibular implant overdentures relative to implant survival rate , maintenance and complications , and patient satisfaction . MATERIAL S AND METHODS A systematic literature search was conducted by a PubMed search strategy and h and - search ing of relevant journals from included studies . R and omized  Clinical  Trials ( RCT ) and comparative clinical trial studies on m and ibular implant overdentures until August , 2010 were selected . Eleven studies from 1098 studies were finally selected and data were analyzed relative to number of implants . RESULTS Six studies presented the data of the implant survival rate which ranged from 95 % to 100 % for 2 and 4 implant group and from 81.8 % to 96.1 % for 1 and 2 implant group . One study , which statistically compared implant survival rate showed no significant differences relative to the number of implants . The most common type of prosthetic maintenance and complications were replacement or reattaching of loose clips for 2 and 4 implant group , and denture repair due to the fracture around an implant for 1 and 2 implant groups . Most studies showed no significant differences in the rate of prosthetic maintenance and complication , and patient satisfaction regardless the number of implants . CONCLUSION The implant survival rate of m and ibular overdentures is high regardless of the number of implants . Denture maintenance is likely not inflenced substantially by the number of implants and patient satisfaction is typically high again regardless os the number of implants STATEMENT OF PROBLEM There is a widespread belief that maxillary overdenture prostheses are associated with a higher frequency of complications and require more maintenance than fixed implant prostheses . PURPOSE This prospect i ve clinical study compared the treatment outcomes of fixed and removable implant-supported restorations in the edentulous maxilla with the main emphasis on the clinician 's point of view . MATERIAL AND METHODS Ten patients were treated with fixed screw-retained implant prostheses ( group 1 ) , and 10 patients were treated with removable implant-supported overdentures ( group 2 ) in the edentulous maxilla . Recall was scheduled at 6-month intervals to investigate the prosthodontic treatment outcomes , including implant survival , prosthesis time until retreatment , and maintenance issues . Clinical parameters gingival index ( GI ) , plaque index ( PI ) , the clinical attachment level , and radiographic marginal bone levels measured , along with any biologic and mechanical complications were recorded . RESULTS Patients were followed over a mean period of 39 months ( SD=7 ; group 1 ) and 27 months ( SD=10 ; group 2 ) after implant placement . Cumulative implant survival was 97.6 % for group 1 and 94.4 % for group 2 after an 18-month observation period . The mean time until retreatment after prostheses insertion was 23.4 months for group 1 and 19.8 months for group 2 ( n.s . ) . In both groups , the increase over time in the radiographically investigated bone level was found to be significant . The indices given for the mucosal health and oral hygiene status ( GI and PI ) were highly correlated in both groups at each recall appointment , but no significant differences were found between groups 1 and 2 . CONCLUSION In groups 1 and 2 , comparable prosthodontic treatment outcomes were achieved . The majority of mechanical complications could be managed chairside during recall visits and did not require additional appointments , so that the time and costs involved in providing maintenance were kept down OBJECTIVE Comparing treatment outcome of four and six bar-connected implants in the anterior maxillary region to support an overdenture during a 1-year follow-up period . MATERIAL AND METHODS Fifty edentulous patients with lack of retention and stability of the upper denture , but with sufficient bone volume to place implants in the anterior maxillary region , were selected . R and omization assigned patients to either four or six implants .  Implant survival , overdenture survival , clinical scores , radiographic bone height changes , and patients ' satisfaction were assessed . RESULTS Forty-nine patients ( one drop out ) completed the 1-year follow-up . After 1 year , implant survival was 100 % in the four implants group and 99.3 % in the six implants group ( one implant lost ) . Overdenture survival was 100 % in both groups . Mean clinical scores were low and did not differ between groups ( independent Student 's t-test ) . Mean marginal bone resorption was 0.24 ± 0.32 mm in the four implants group and 0.25 ± 0.29 mm in the six implants group . Patients ' satisfaction had improved in both groups ( paired Student 's t-test ) . CONCLUSION Bar-supported overdentures on four implants in the anterior maxillary region are not inferior to overdentures supported by six bar-connected implants . Implant survival was high , peri-implant conditions were healthy and patients ' satisfaction had increased significantly in both groups STATEMENT OF PROBLEM The results of the  implant overdenture treatment in the maxilla remains inferior to those in the m and ible . Different reasons have been alluded to , such as bone quality and quantity , number of implants , as well as the prosthesis design . PURPOSE To investigate the latter , a new design for the rehabilitation of the resorbed maxillae was set up . MATERIAL AND METHODS Thirteen patients were selected and provided with four endosseous maxillary implants  , splinted with a rigid-cast bar . RESULTS After a mean loading time of 3 years , six implants were lost ; three at abutment and another three shortly after abutment connection , result ing in a cumulative success rate of 88.6 % at year 4 . A mean marginal bone loss of 0.3 mm was observed within the first year . After the first year , the marginal bone level , the attachment level , and the Periotest scores hardly changed . The main prosthetic complication was the frequent need to renew or to activate the attachments . A strong improvement in patient satisfaction was observed when compared with the old conventional denture . CONCLUSIONS Within the limits of this study , the outcome confirmed that , on a medium-term base , implant-retained hinging overdentures on four implants were promising PURPOSE To analyze maintenance service of fixed maxillary prostheses and overdentures based on conventional gold bars or titanium bars and frameworks fabricated with computer-aided design /computer-assisted manufacture ( CAD/CAM ) technology . MATERIAL S AND METHODS Forty-one patients participated ; 16 received an implant overdenture with a gold bar ( gold OD ) , 12 received a CAD/CAM-fabricated implant OD with a titanium bar ( Ti OD ) , and 13 received a  CAD/CAM implant-supported fixed prosthesis ( IFP ) . The bars and frameworks were screw-retained at the implant level . Maintenance service performed during the first 2 years was recorded and compared between the three groups . After this 2-year period , the Oral Health Impact Profile ( OHIP ) was administered . RESULTS For ODs ( gold , Ti ) most service consisted of activation of the matrices . Fractures of matrices and bar extensions occurred only in the gold OD group , and 65 % of these patients exhibited hyperplasia of the peri-implant mucosa . The maintenance rates were 1.24 ( gold OD ) , 1.36 ( Ti OD ) , and 0.98 ( IFP ) . These differences were not statistically significant . Retightening of occlusal screws was not necessary in any group . The probability that a complication occurred in the first year was high ( 60 % to 70 % ) and statistically not different between the three groups . The probability that a second complication occurred was significantly lower for the IFP group versus the gold OD group . The mean OHIP values were 1.7 ( IFP ) , 6.7 ( gold OD ) , and 7.3 ( Ti OD ) ; ratings in the IFP group were significantly better . CONCLUSIONS Maintenance service was typical for implant prostheses in the edentulous maxilla . Direct screw retention at the implant level without abutments had a favorable effect in all groups . A trend toward a reduction in problems was observed with the CAD/CAM superstructures . The OHIP confirmed high satisfaction , but quality of life appeared to be slightly higher with fixed prostheses OBJECTIVE The aim of this 5-year prospect i ve comparative study was to evaluate treatment outcome ( survival rate , condition of hard and soft peri-implant tissues , patient satisfaction , prosthetic and surgical aftercare ) of m and ibular overdentures supported by two or four implants .  MATERIAL AND METHODS Sixty edentulous patients with a m and ibular height between 12 and 18 mm participated . Thirty patients were treated with an overdenture supported by two IMZ implants ( group A ) and 30 patients were treated with an overdenture supported by four IMZ implants ( group B ) . St and ardised clinical and radiographic parameters were evaluated 6 weeks after completion of the prosthetic treatment and after 1 , 2 , 3 , 4 and 5 years of functional loading . Prosthetic and surgical aftercare was scored during the evaluation period . RESULTS One implant was lost ( group A ) during the healing period . There were no significant differences with regard to any of the studied clinical or radiographic parameters of the peri-implant tissues between the groups . None of the patients reported sensory disturbances in the lip or chin region . No differences in satisfaction were observed between the groups . With regard to aftercare , there was a tendency of a greater need of prosthetic interventions in group A , while correction of soft-tissue problems was restricted to patients of group B. CONCLUSION There is no difference in clinical and radiographical state of patients treated with an overdenture on two or four implants during a 5-year evaluation period . Patients of both groups were as satisfied with their overdentures The aim of this study was to evaluate the suitability of resorbable screws made of poly ( D.L-lactide ) acid ( PDLLA ) for fixation of autologous bone grafts related to graft regeneration and osseointegration of dental implants . In eight edentulous patients suffering from insufficient retention of their upper denture related to a severely resorbed maxilla , the floor of both maxillary sinus and width of the alveolar crest were augmented with an autologous bone graft from the iliac crest . R and omly , the bone graft used to augment the alveolar crest was fixed with two titanium screws on one side and two resorbable screws on the other side ( split-mouth design ) . Three months after the reconstruction , a bone biopsy was taken with a trephine including one resorbable screw ( N = 8) . Subsequently , six implants were placed in the left and 
    Output:
    
An implant-supported maxillary overdenture ( all studies ≥ 4 implants ) provided with a splinted anchorage is accompanied with a high implant and overdenture survival rate ( both > 95 % per year ) , while there is an increased risk of implant loss when ≤ 4 implants with a non-splinted anchorage are used