***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 aim of this study of the present experiment was to study the marginal periimplant tissues at intentionally non-submerged ( 1-stage implants ) and initially submerged and subsequently exposed implants ( 2-stage implants ) . 5 beagle dogs , about 1-year-old , were used , 3 months after the extraction of the m and ibular premolars , fixtures of the Astra Tech Implants Dental System , the Brånemark System and the Bonefit -- ITI system were installed . In each m and ibular quadrant , 1 fixture of each implant system was installed in a r and omised order . The installation procedure followed the recommendations given in the manuals for each system . Thus , following installation , the bone crest coincided with the fixture margin of the Astra Tech Implants Dental System and the Brånemark System , whereas the border between the plasma sprayed and the machined surface of the Bonefit-ITI implant system was positioned at the level of the bone crest . Following a healing period of 3 months , abutment connection was carried out in the 2-stage systems ( the Astra Tech Implants Dental System and the Brånemark system ) . A 6-month period of plaque control was initiated . The animals were sacrificed and biopsies representing each important region dissected . The tissue sample s were prepared for light microscopy and exposed to histometric and morphometric measurements . The mucosal barrier which formed to the titanium surface following 1-stage and 2-stage implant installations comprised an epithelial and a connective tissue component , which for that 3 systems studied , had similar dimensions and composition . The amount of lamellar bone contained in the periimplant region close to the fixture part of the 3-implant systems was almost identical . It is suggested that correctly performed implant installation may ensure proper conditions for both and hard tissue healing , and that the geometry of the titanium implant seems to be of limited importance OBJECTIVES To ( i ) investigate the influence of different extensions of a laser microgrooved abutment zone on connective tissue attachment and ( ii ) assess the impact of a repeated abutment dis-/reconnection on soft- and hard-tissue healing . MATERIAL S AND METHODS Titanium implants were inserted epicrestally in the lower jaws of six dogs . Healing abutments with either partially ( LP ) or completely ( LC ) laser microgrooved margins or machined surface margins ( M ) were r and omly allocated either to a single (1 × )/repeated ( 2 × ) dis-/reconnection at 4 and 6 weeks ( test ) , respectively , or left undisturbed ( control ) . At 6 and 8 weeks , histomorphometrical ( e.g. most coronal level of bone in contact with the implant [ CBI ] , subepithelial connective tissue attachment [ STC ] ) and immunohistochemical ( Collagen Type-I [ CI ] ) parameters were assessed . RESULTS At control sites , LP/LC groups revealed lower mean CBL ( 8 weeks , 0.95 ± 0.51 vs. 0.54 ± 0.63 vs. 1.66 ± 1.26 mm ) , higher mean STC ( 8 weeks , 82.58 ± 24.32 % vs. 96.37 ± 5.12 % vs. 54.17 ± 8.09 % ) , but comparable CI antigen reactivity . A repeated abutment manipulation was associated with increased mean CBL ( 8 weeks , 1.53 ± 1.09 vs. 0.94 ± 0.17 vs. 1.06 ± 0.34 mm ) , decreased STC ( 8 weeks , 57.34 ± 43.06 % vs. 13.26 ± 19.04 % vs. 37.76 ± 37.08 % ) and CI values . CONCLUSIONS It was concluded that ( i ) LC > LP abutments enhanced subepithelial connective tissue attachment and preserved crestal bone levels , ( ii ) repeated abutment dis-/reconnection during the initial healing phase ( 4 - 6 weeks ) may be associated with increased soft- and hard-tissue changes and ( iii ) LP and LC should be considered using a one abutment , one time approach Limited information exists regarding soft tissue and hard tissue responses to abutments with different material composition . The aim of this study is to evaluate soft and hard tissue responses to titanium and polymer healing abutments over a 3-month period . Sixteen patients were included in this prospect i ve trial . Implants were provisionalized with either titanium or polymer healing abutments .  Changes of marginal bone level and soft tissue dimensions were recorded at implant installation and at 3 months Previous research has demonstrated the effectiveness of laser-ablated microgrooves placed on implant collars to support direct connective tissue attachments to altered implant surfaces . Such a direct connective tissue attachment serves as a physiologic barrier to the apical migration of the junctional epithelium and prevents crestal bone resorption . The current prospect i ve pre clinical trial sought to evaluate bone and soft tissue healing patterns when laser-ablated microgrooves were placed on the abutment . A canine model was selected for comparison to previous investigations that examined the negative bone and soft tissue sequelae of the implant-abutment microgap . The results demonstrate significant improvement in peri-implant hard and soft tissue healing compared to traditional machined abutment surfaces OBJECTIVE To evaluate the marginal soft and hard tissue healing at titanium and Polyetheretherketone ( PEEK ) healing implant abutments over a 4-month period . MATERIAL AND METHODS In six Labrador dogs , all m and ibular premolars and first molars were extracted . After 4 months of healing , flaps were elevated , and two implants were installed at each side of the m and ible , one in the premolar and the other in the molar regions . Four different types of healing abutments were positioned on the top of each implant : ( i ) titanium ( Ti ) ; ( ii ) PEEK material bonded to a base made of titanium ( Ti-P ) , r and omly positioned in the premolar region ; ( iii ) PEEK , pristine ( P ) ; and ( iv ) PEEK , roughened ( P-R ) , r and omly positioned in the molar region . The flaps were sutured to allow a non-submerged healing , and after 4 months , the animals were sacrificed and ground sections obtained for histological evaluation . RESULTS A higher resorption of the buccal bone crest was observed at the PEEK bonded to a base made of titanium abutments ( 1.0 ± 0.3 mm ) compared to those made of titanium ( 0.3 ± 0.4 mm ) . However , similar dimensions of the peri-implant mucosa and similar locations of the soft tissues in relation to the implant shoulder were observed . No statistically significant differences were seen in the outcomes when the pristine PEEK was compared with the roughened PEEK abutments . The mean apical extension of the junctional epithelium did not exceed the implant shoulder at any of the abutment types used . CONCLUSIONS The coronal level of the hard and soft tissues allows the conclusion that the use of PEEK as healing abutments may be indicated OBJECTIVE Microorganisms harboring the oral cavity , mainly those related to periodontal diseases , are the most potential etiologic factor of failure in long-term implant treatment . The material used for abutment components may influence the adhesion and colonization of microbial species . The aim of this in vivo investigation was to evaluate the biofilm formation on machined ( MPT ) or cast titanium ( CPT ) and zirconia abutments ( Zc ) . METHODS Six healthy subjects were enrolled in this r and omized crossover clinical investigation . The study was conducted in three phases according to abutment surface evaluated . Each subject used an individual oral splint containing four disks of the same tested substrate , two located in the anterior and two in the posterior region , totalizing 12 specimens for subject . Participants were asked to use the removable intraoral splint during 24 h.  DNA checkerboard hybridization  method was used to identify and quantify 38 bacterial species colonizing formed biofilm on the abutment substrates . RESULTS Pathogens and non-pathogens species were found colonizing the three substrates surfaces . Fusobacterium nucleatum , Neisseria mucosa , Porphyromonas aeruginosa , Peptostreptococcus anaerobios , Staphylococcus aureus , Streptococcus gordonii , Streptococcus parasanguinis , and Tanerella forsythia were the only species with no significant differences over the tested material s ( P > 0.05 ) . All the other target species presented significant differences sought by Friedman test ( P < 0.0001 ) . CONCLUSIONS There was a significant difference in the total bacterial count between the three groups . CPT presented the higher mean counts , followed by MPT and Zc . CPT group also showed a higher mean incidence of species than MPT and Zc . The anterior or posterior region of disks placement did not show significant differences in relation to bacterial adhesion OBJECTIVE The aim of the present study was to analyze the soft tissue barrier formed to implant abutments made of different material s. MATERIAL AND METHODS Six Labrador dogs , about 1 year old , were used . All m and ibular premolars and the first , second and third maxillary premolars were extracted . Three months later four implants ( OsseoSpeed , 4.5 x 9 mm , Astra Tech Dental , Mölndal , Sweden ) were placed in the edentulous premolar region on one side of the m and ible and healing abutments were connected . One month later , the healing abutments were disconnected and four new abutments were placed in a r and omized order . Two of the abutments were made of titanium ( Ti ) , while the remaining abutments were made of ZrO(2 ) or AuPt-alloy . A 5-months plaque control program was initiated . Three months after implant surgery , the implant installation procedure and the subsequent abutment shift were repeated in the contra-lateral m and ibular region . Two months later , the dogs were euthanized and biopsies containing the implant and the surrounding soft and hard peri-implant tissues were collected and prepared for histological analysis . RESULTS It was demonstrated that the soft tissue dimensions at Ti- and ZrO(2 ) abutments remained stable between 2 and 5 months of healing . At Au/Pt-alloy abutment sites , however , an apical shift of the barrier epithelium and the marginal bone occurred between 2 and 5 months of healing . In addition , the 80-mum-wide connective tissue zone lateral to the Au/Pt-alloy abutments contained lower amounts of collagen and fibroblasts and larger fractions of leukocytes than the corresponding connective tissue zone of abutments made of Ti and ZrO(2 ) . CONCLUSION It is suggested that the soft tissue healing to abutments made of titanium and ZrO(2 ) is different to that at abutments made of AuPt-alloy OBJECTIVES To investigate ( i ) the impact of different  titanium implant surfaces  on soft tissue integration over 6 months , and ( ii ) the influence of frequent clinical probing during the healing phase on the established mucosal seal . MATERIAL AND METHODS St and ardized clinical probing was r and omly performed ( 12 dogs , probing versus control ) at different transmucosal surfaces [ machined ( M ) , s and -blasted/acid-etched ( SLA ) , and chemically modified acid-etched ( modA ) , modSLA ] at 2 , 4 , 8 , and 12 weeks ( i.e. 1 x , 2 x , 3 x , and 4 x ) . Histomorphometrical analysis ( e.g. mucosal margin ( PM ) - apical extension of the junctional epithelium ( aJE ) , PM - coronal level of bone-to-implant contact ( CBI ) was performed at 4 , 8 , 12 , and 24 weeks . RESULTS While M and SLA groups revealed a split formation , epithelial cells and connective tissue were in close contact to modA and modSLA surfaces . Frequent clinical probing ( i.e. 3 x and 4 x ) increased mean pocket depths , PM-aJE , and aJE-CBI values in all groups and markedly disrupted the epithelial and connective tissue attachment . CONCLUSIONS It was concluded that irrespective of the surface characteristics , a frequent clinical probing at short intervals during the healing phase was associated with dimensional and structural changes of the mucosal seal 
    Output:
    
Comparable results in terms of peri-implant attachment dimensions between test and control groups were found , except for a significantly higher apical junctional epithelium to coronal bone to implant ( ajE-CBI ) distance for chemically modified acid-etched compared with titanium machined surfaces .
Non-meta-analyzable and /or qualitative results highlighted some improved properties also for microgrooved and oxidized surfaces .
Limited data from animal studies suggest that some characteristics of the transmucosal implant components may affect peri-implant soft-tissue adhesion and stabilization but do not allow definitive conclusions .