Evidence analysis shows that the present knowledge about biologic width around implants is mainly derived from animal studies and that clinical controlled human studies are insufficient
PURPOSE The concept of biologic width forms a basis for successful peri-implant soft tissue integration around titanium implants .
Therefore , the objectives of this review are to determine and critically evaluate the present knowledge about biologic width around implants and to establish future research trends .
Influence of the size of the microgap on crestal bone changes around titanium implants. A histometric evaluation of unloaded non-submerged implants in the canine mandible.
BACKGROUND Endosseous implants can be placed according to a non-submerged or submerged approach and in 1- or 2-piece configurations . Recently , it was shown that peri-implant crestal bone changes differ significantly under such conditions and are dependent on a rough/smooth implant border in 1-piece implants and on the location of an interface ( microgap ) between the implant and abutment/restoration in 2-piece configurations . Several factors may influence the result ant level of the crestal bone under these conditions , including movements between implant components and the size of the microgap ( interface ) between the implant and abutment . However , no data are available on the impact of possible movements between these components or the impact of the size of the microgap ( interface ) . The purpose of this study was to histometrically evaluate crestal bone changes around unloaded , 2-piece non-submerged titanium implants  with 3 different microgap ( interface ) dimensions and between implants with components welded together or held together by a transocclusal screw . METHODS A total of 60 titanium implants were r and omly placed in edentulous m and ibular areas of 5 hounds forming 6 different implant subgroups ( A through F ) . In general , all implants had a relatively smooth , machined suprabony portion 1 mm long , as well as a rough , s and blasted , and acid-etched ( SLA ) endosseous portion , all placed with their interface ( microgap ) 1 mm above the bone crest level and having abutments connected at the time of first-stage surgery . Implant types A , B , and C had a microgap of < 10 microns , approximately 50 microns , or approximately 100 microns between implant components as did types D , E , and F , respectively . As a major difference , however , abutments and implants of types A , B , and C were laser-welded together , not allowing for any movements between components , as opposed to types D , E , and F , where abutments and implants were held together by abutment screws . Three months after implant placement , all animals were sacrificed . Non-decalcified histology was analyzed histometrically by evaluating peri-implant crestal bone changes . RESULTS For implants in the laser-welded group ( A , B , and C ) , mean crestal bone levels were located at a distance from the interface ( IF ; microgap ) to the first bone-to-implant contact ( fBIC ) of 1.06 + /- 0.46 mm ( st and ard deviation ) for type A , 1.28 + /- 0.47 mm for type B , and 1.17 + /- 0.51 mm for type C. All implants of the non-welded group ( D , E , and F ) had significantly increased amounts of crestal bone loss , with 1.72 + /- 0.49 mm for type D ( P < 0.01 compared to type A ) , 1.71 + /- 0.43 mm for type E ( P < 0.02 compared to type B ) , and 1.65 + /- 0.37 mm for type F ( P < 0.01 compared to type C ) . CONCLUSIONS These findings demonstrate , as evaluated by non-decalcified histology under unloaded conditions in the canine m and ible , that crestal bone changes around 2-piece , non-submerged titanium implants are significantly influenced by possible movements between implants and abutments , but not by the size of the microgap ( interface ) . Thus , significant crestal bone loss occurs in 2-piece implant configurations even with the smallest-sized microgaps ( < 10 microns ) in combination with possible movements between implant components
Evidence analysis shows that the present knowledge about biologic width around implants is mainly derived from animal studies and that clinical controlled human studies are insufficient
PURPOSE The concept of biologic width forms a basis for successful peri-implant soft tissue integration around titanium implants .
Therefore , the objectives of this review are to determine and critically evaluate the present knowledge about biologic width around implants and to establish future research trends .