. characteristics of the implant surface include the topographical characteristics of the surface , thickness of the titanium oxide layer , porosity of the surface , and chemical composition of the surface .
surface treatment is known to stabilize blood clot formation , increase fibrin attachment , and promote migration and differentiation of cells , which influences bone formation at early stages12 .
however , evaluation of various methods is still ongoing in an effort to establish the optimal surface treatment .
most of the studies to date that have been conducted on implant surface treatments are based on cell or animal experiments .
furthermore , there has been little work with regard to the analysis of the bone - implant contact ( bic ) ratio , which is closely related to the implant surface treatment method .
the purpose of this study was to analyze the bic ratio of a resorbable blasting media ( rbm ) surface - treated implant retrieved from humans , and to compare this with the bic ratio of implants using other surface treatment methods .
a 78-year - old female patient visited the hospital complaining about gingival pain and swelling in an implant of the left mandibular molar region .
a radiograph that showed the rbm surface of the implant ( osstem , busan , korea ) was obtained , and crestal bone loss was observed.(fig .
1 ) the dental prosthesis in the coronal portion of the implant was removed , and her progress had been observed for one year . the patient continued to complain of discomfort and asked for removal of the implant . a trephine bur was used to remove implants # 36 and # 37 .
the resulting bone defect was resolved with bio - oss ( geistlich pharma ag , wolhusen , switzerland ) before being covered with bio - gide ( geistlich pharma ag ) .
a 46-year - old male patient visited the hospital , complaining that the screw of implant fixture # 46 had loosened after the implant was placed in a dental clinic one year previously . according to the examination
, the rbm surface of the implant ( osstem ) was found to be slanted toward the center of a circle , while the implant platform had lost its original form .
2 ) a trephine bur was used to remove the implant , and the material exfuse ( hanmi inc . ,
seoul , korea ) was used for the bone graft ; bio - gide ( geistlich pharma ag ) was then used for coverage .
after 18 months , an implant was placed again . immediately after the implant was removed ,
it was placed into 10% formalin solution for fixation , soaked in 70% alcohol for further fixation for six days , and then washed in running water for 24 hours . for dehydration ,
next , the implant was embedded with a glycomethacrylate resin ( spurr low - viscosity embedding media , polyscience , pa , usa ) and polished to a thickness of approximately 200 m , parallel to the major axis of implant , which was to the manufacturer ' s specifications .
after villanueva osteochrome bone stain ( sbt , sans clemente , ca , usa ) was performed , an optical microscope ( olympus bx51 ; olympus , tokyo , japan ) was used to analyze the bic ratio of the two specimens that were manufactured for each implant .
the bic ratio was calculated from the highest point of remaining bone using the following equation .
bic ratio ( % ) = ( length of bone in contact with implant surface / total length of implant surface)100 ring - shaped bone loss was observed surrounding implant # 36 .
however , the first screw line of the implant was not exposed . in several parts
, the implant was found to be separated from bone , which seemed to be a defect created during specimen manufacturing .
interposition of connective tissue was not found between implant and bone , and it was observed that a solid bone with a small medullary cavity was formed . the bic ratio measured in the two specimens was 78% and 75% , respectively.(fig .
3 ) bone resorption of implant # 37 was in progress up to the second screw line , and a degree of bone resorption was found in the specimen .
bone separation was found on both sides of the specimen , which was attributable to a defect in the process of manufacturing .
4 ) a significant bone loss was found in implant # 46 , due to an inappropriate occlusal force .
the defect created when the implant was removed led to the specimen in which the implant was observed to be separated from bone .
new bone was formed densely between screw lines , and the bic ratio measured in the two specimens was 52% and 68% , respectively .
a 78-year - old female patient visited the hospital complaining about gingival pain and swelling in an implant of the left mandibular molar region .
a radiograph that showed the rbm surface of the implant ( osstem , busan , korea ) was obtained , and crestal bone loss was observed.(fig .
1 ) the dental prosthesis in the coronal portion of the implant was removed , and her progress had been observed for one year . the patient continued to complain of discomfort and asked for removal of the implant . a trephine bur was used to remove implants # 36 and # 37 .
the resulting bone defect was resolved with bio - oss ( geistlich pharma ag , wolhusen , switzerland ) before being covered with bio - gide ( geistlich pharma ag ) .
a 46-year - old male patient visited the hospital , complaining that the screw of implant fixture # 46 had loosened after the implant was placed in a dental clinic one year previously . according to the examination
, the rbm surface of the implant ( osstem ) was found to be slanted toward the center of a circle , while the implant platform had lost its original form .
2 ) a trephine bur was used to remove the implant , and the material exfuse ( hanmi inc . ,
seoul , korea ) was used for the bone graft ; bio - gide ( geistlich pharma ag ) was then used for coverage .
immediately after the implant was removed , it was placed into 10% formalin solution for fixation , soaked in 70% alcohol for further fixation for six days , and then washed in running water for 24 hours . for dehydration
next , the implant was embedded with a glycomethacrylate resin ( spurr low - viscosity embedding media , polyscience , pa , usa ) and polished to a thickness of approximately 200 m , parallel to the major axis of implant , which was to the manufacturer ' s specifications .
after villanueva osteochrome bone stain ( sbt , sans clemente , ca , usa ) was performed , an optical microscope ( olympus bx51 ; olympus , tokyo , japan ) was used to analyze the bic ratio of the two specimens that were manufactured for each implant .
the bic ratio was calculated from the highest point of remaining bone using the following equation .
bic ratio ( % ) = ( length of bone in contact with implant surface / total length of implant surface)100 ring - shaped bone loss was observed surrounding implant # 36 .
however , the first screw line of the implant was not exposed . in several parts ,
the implant was found to be separated from bone , which seemed to be a defect created during specimen manufacturing .
interposition of connective tissue was not found between implant and bone , and it was observed that a solid bone with a small medullary cavity was formed . the bic ratio measured in the two specimens was 78% and 75% , respectively.(fig .
3 ) bone resorption of implant # 37 was in progress up to the second screw line , and a degree of bone resorption was found in the specimen .
bone separation was found on both sides of the specimen , which was attributable to a defect in the process of manufacturing .
4 ) a significant bone loss was found in implant # 46 , due to an inappropriate occlusal force .
the defect created when the implant was removed led to the specimen in which the implant was observed to be separated from bone .
new bone was formed densely between screw lines , and the bic ratio measured in the two specimens was 52% and 68% , respectively .
however , the first screw line of the implant was not exposed . in several parts ,
the implant was found to be separated from bone , which seemed to be a defect created during specimen manufacturing .
interposition of connective tissue was not found between implant and bone , and it was observed that a solid bone with a small medullary cavity was formed . the bic ratio measured in the two specimens was 78% and 75% , respectively.(fig .
3 ) bone resorption of implant # 37 was in progress up to the second screw line , and a degree of bone resorption was found in the specimen .
bone separation was found on both sides of the specimen , which was attributable to a defect in the process of manufacturing .
a significant bone loss was found in implant # 46 , due to an inappropriate occlusal force .
the defect created when the implant was removed led to the specimen in which the implant was observed to be separated from bone .
new bone was formed densely between screw lines , and the bic ratio measured in the two specimens was 52% and 68% , respectively .
sandblasted with large grit and acid etching ( sla ) surface treatment method consists of acid etching after media blasting .
the method is to create uniform roughness and increase surface porosity , which reduces the time to bone integration 3 .
such a porous structure is known to be formed layer by layer with a thickness of 1 to 100 m .
surface treatment with hydroxyapatite ( ha ) is known to reduce the time to bone integration because of its biocompatibility .
ha has a high binding force between serum protein and growth factor and thus can promote attachment and proliferation of osteoblasts . as a result ,
brunel et al.9 reported that the bic ratio of ha - coated implant was 74% .
in most of the cases , the ha - coated implant was placed in the maxillary molar region .
anodic oxidation coating enables the ability to increase the thickness of the titanium oxide layer and maintain ions on the surface . when the anodic oxidation coating is used , it is possible to increase the thickness of the titanium oxide layer from 1,000 nm up to 5,000 nm and incorporate active ions of mg , ca , and p on the surface of the titanium oxide layer .
it has been known that the reaction of positive ions can promote aggregation and attachment of initial protein and ligand - mediated reaction1112 .
tiunite ( nobelbiocare , gteborg , sweden ) implant is a typical p - incorporated implant . in particular
, sul11 reported that the bic ratio of implants incorporated with calcium and phosphorus ions increased by 2.7 times and 2.3 times , respectively , compared to those of the existing machined implant .
especially , rocci et al.13 reported that the bic ratio of anodized surface implants ranged from 67.1% to 95.5% on posterior mandibular area .
dual - acid etched method is used to surface - treat an implant with two or more mixed methods or to surface - treat implants using complex methods separately for upper and lower components .
a typical implant is osseotite ( biomet 3i implant innovations , palm beach gardens , fl , usa ) that is treated with acid .
davies14 reported that the osseotite surface treatment technique could reduce the healing period to eight weeks .
in addition , that report showed that the technique enabled fibrin to attach well to the surface of the implant , which stabilized the blood clot and helped resist micromovement of the implant .
the bic ratio for these implants ranged from 48.6% to 81.5%151617 . on the rbm surface ,
bone - compatible material was used as blasting media for etching the implant , which increased the surface area and bic ratio strength .
recently , many surface treatment methods have emerged that are sub - categorized according to the particle component used for rbm surface treatment , roughness , condition of processing temperature , and post - processing . according to studies on stability of implants
, there is a high correlation between implant removal torque values and the bic ratio , and between the bic ratio and resonance frequency analysis value31819 .
kim et al.19 conducted a study on the stability of an implant that was treated with rbm and placed in the maxillary molar region .
these researchers reported that the implant stability quotient was 63.6 for implant placement and 74.4 for the second surgery .
these researchers also reported that no significant alveolar bone resorption was found , indicating excellent clinical results . in this study ,
the bic ratio of rbm - treated implants retrieved from humans was 69.0%9.1% on average , which was similar to the range for sla or ha coating .
although the second case report showed that bone resorption in the surroundings of the implant was relatively high , the bone resorption was believed to be attributable to traumatic occlusion , rather than to inflammation in the surroundings of the implant .
as changes have been made in the content of calcium and phosphorus and the blasting method of the rbm implant , many comparative studies have been conducted recently .
the study of the characteristics of the implant surface has immense potential and could be used to expedite development of implants in the future .
therefore , it has been impossible to confirm successful results from a histological perspective , which is a major limitation of studies conducted to date .
consequently , it is necessary to verify study results with clinical data that are collected over an extended time period . in conclusion , even though the number of implants examined in this study was small , it was clear that rbm surface - treated implants placed in humans do not show a large difference in bic ratio compared to other surface - treated implants .
 the purpose of this study is to evaluate the degree of osseointegration of resorbable blasting media ( rbm ) surface implants retrieved from humans . 
 three implants in the mandibular molar region that were surface - treated with rbm were retrieved from two patients . 
 the implants were used to manufacture specimens in order to measure the bone - implant contact ( bic ) ratio . the bic ratios of the three implants were found to be an average of 69.0%9.1% . in conclusion , that rbm surface implants are integrated into the host environment with histological significance and the bic ratio of the rbm surface - treated implant was not significantly different from that of other surface - treated implants . 
I. Introduction
II. Cases Report
1. Case 1
2. Case 2
3. Specimen processing and measurement of BIC ratio
1) Case 1
2) Case 2
III. Discussion