Sinus augmentation using absorbable collagen sponge loaded with Escherichia coli-expressed recombinant human bone morphogenetic protein 2 in a standardized rabbit sinus model: a radiographic and histologic analysis

Objectives: The purpose of this pilot study was to determine the osteoinductive effect of absorbable collagen sponge (ACS) loaded with Escherichia coli‐expressed recombinant human bone morphogenetic protein 2 (ErhBMP‐2) and evaluate structural stability of ACS in a standardized rabbit sinus model. Material and methods: The maxillary sinuses were prepared bilaterally in six male white rabbits. The windows were prepared using a 6 mm trephine bur, and circular bony windows were carefully removed. Following reflection of the sinus membrane, a saline‐soaked ACS alone and an ErhBMP‐2‐loaded ACS were inserted into the left and right maxillary sinuses, respectively. After a healing period of 8 weeks, sections of the augmented sinus and surrounding bone were made and analyzed by microcomputed tomography and histologically for signs of window closure and bone augmentation. Results: Radiographic analysis revealed new bone formation in both groups of augmented sinus (i.e., with and without ErhBMP‐2). The maximum augmented height did not differ significantly between the groups; however, window closure was significantly more advanced in the ErhBMP‐2 group than in the control group (P=0.02). The defect was significantly deeper in the control group than in the ErhBMP‐2‐treated group (P=0.02). Conclusions: In conclusion, ErhBMP‐2‐loaded ACS showed enhanced osteoinductive potential, particularly with regard to bone closure of a sinus window and facilitated maturation of the newly formed bone within the rabbit sinus cavity. However, the structural durability of ACS was not sufficient to maintain the augmented volume in the sinus.     

Bone formation of block and particulated biphasic calcium phosphate lyophilized with Escherichia coli-derived recombinant human bone morphogenetic protein 2 in rat calvarial defects

The objective of this study was to evaluate bone formation in rat calvarial defects after surgical implantation of block or particulated biphasic calcium phosphate (BCP) lyophilized with Escherichia coli-derived recombinant human bone morphogenetic protein 2 (ErhBMP-2). Critical-size calvarial osteotomy defects were created in 5 groups of Sprague-Dawley rats. Each group received one of the following: 1) sham surgery control; 2) biphasic calcium phosphate particles (CPP); 3) biphasic calcium phosphate block (CPB); 4) ErhBMP-2-coated CPP; or 5) ErhBMP-2-coated CPB. ErhBMP was coated on BCP by a stepwise lyophilizing protocol. The new bone formation was significantly greater in ErhBMP-2-treated groups compared with the untreated group. In particular, the ErhBMP-2/CPB group showed stability of augmented areas during the period of healing, due to relevant space-providing capacity. Thus, it can be concluded that CPP and CPB lyophilized with ErhBMP-2 enhance the formation of new bone, and CPB appears to be a suitable carrier for ErhBMP-2 in which a 3-dimensional structural integrity is an important consideration factor.     

Effect of recombinant human bone morphogenetic protein-2 on bone formation in the acute distraction osteogenesis of rat mandibles

Background: Distraction osteogenesis (DO) is a method of producing new bone directly from the osteotomy site by gradual traction of the divided bone fragments.
Aim: The purpose of the present study was to evaluate histomorphometrically whether acute DO would constitute a viable alternative to the conventional continuous distraction treatment and also to verify the capacity of a recombinant human BMP (rhBMP-2) associated with monoolein gel to stimulate bone formation in the acute distraction process.
Materials and methods: Forty-eight Wistar rats were assigned to three groups: Group 1, treated at a conventional continuous distraction rate (0.5 mm/day), Group 2, treated with acute distraction of 2.5 mm at the time of the surgical procedure, and Group 3, subjected to acute distraction associated with rhBMP-2. The animals from each experimental group were killed at the end of the second or fourth post-operative weeks and the volume fraction of newly formed bone trabeculae was estimated in histological images by a differential point-counting method.
Results: The results showed that after 2 and 4 weeks, bone volumes in the rhBMP-2 group were significantly higher than in the other groups ( P <0.05), but no significant difference was observed in the volume fraction of newly formed bone between the continuous and acute DO groups.
Conclusion: In conclusion, the study indicates that rhBMP-2 can enhance the bone formation at acute DO, which may potentially reduce the treatment period and complications related to the distraction procedure.     

骨形态发生蛋白-2与碱性成纤维细胞生长因子在异位和原位成骨中的作用

目的通过骨髓基质细胞（BMSCs）的体外增殖和分化、异位成骨和原位成骨实验来观察骨形态发生蛋白-2（BMP-2）和碱性成纤维细胞生长因子（bFGF）在成骨过程中的作用。方法分别用含BMP-2、bFGF和BMP-2+bFGF的培养液体外培养Beagle犬的BMSCs,通过甲基噻唑基四唑（MTT）比色法测定细胞增殖水平,通过测定碱性磷酸酶（ALP）活性观察细胞的分化情况。将BMSCs与多孔磷酸钙（CPC）分别在含BMP-2、bFGF和BMP-2+bFGF的培养液中复合培养,制成复合材料,一部分植入裸鼠皮下,观察异位成骨情况,另一部分植入Beagle犬的种植体周围骨缺损区,经过荧光标记观察原位成骨情况。结果含有BMP-2+bFGF的培养液促进BMSCs增殖和分化的能力最强。异位成骨情况：BMP-2+bFGF组的成骨量较其他组明显增加,其新骨形成百分比为48.79%±11.31%,高于单一BMP-2组（30.71%±10.85%）和bFGF组（27.33%±9.67%）以及对照组（10.65%±6.05%）。原位成骨术后12周,BMP-2+bFGF组的矿化沉积率高于其他组,其差异有统计学意义（P<0.01）。结论在促进成骨方面,BMP-2和bFGF共同作用优于单一因子。     

Platelet-rich plasma and fibrin as delivery systems for recombinant human bone morphogenetic protein-2

The aim of the present study was (1) to test whether or not platelet-rich plasma (PRP) or commercially available fibrin can increase bone regeneration compared with non-treated defects and (2) to test whether or not PRP or fibrin increases bone regeneration when used as a delivery system for recombinant human bone morphogenetic protein-2 (rhBMP-2). In 16 New Zealand White rabbits, four evenly distributed 6 mm diameter defects were drilled into the calvarial bone. The following five treatment modalities were randomly allocated to all 64 defects: (0) untreated control, (1) fibrin alone, (2) PRP alone, (3) fibrin with 15 microg rhBMP-2 and (4) PRP with 15 microg rhBMP-2. For the fibrin gels and the PRP containing rhBMP-2, the 15 microg rhBMP-2 was incorporated by precipitation within the matrices before their gelation. After 4 weeks, the animals were sacrificed and the calvarial bones were removed for histological preparation. The area fraction of newly formed bone was determined in vertical sections from the middle of the defect by applying histomorphometrical analysis. A mean area fraction of newly formed bone was found within the former defect of 23.4% (+/-13.5%) in the control sites, of 28.4% (+/-17.4%) in the fibrin sites and of 34.5% (+/-17.4%) in the PRP sites. The statistical analysis revealed no significant difference in bone formation between the three groups (ANOVA). Addition of 15 microg rhBMP-2 in the fibrin gel (59.9+/-20.3%) and the PRP gels (63.1+/-25.3%) increased bone formation significantly. No significant difference was observed between sites, where PRP or fibrin has been used as a delivery system for rhBMP-2 (ANOVA). In conclusion, the application of fibrin gels or PRP gels to bone defects is not superior to leaving the defect untreated. Regarding the amount of bone formation, the application of 15 microg rhBMP-2 in bone defects enhances the healing significantly at 4 weeks. In this animal model, commercially available fibrin and autologous PRP gels are equally effective as delivery systems for rhBMP-2.     

Expression of bone morphogenetic protein in the course of osteoinduction by recombinant human bone morphogenetic protein-2

To clarify the mechanism of osteoinduction by recombinant human bone morphogenetic protein-2 (rhBMP-2), we examined the time-course localization of bone morphogenetic proteins (BMPs) immunostained by an anti-BMP-2 monoclonal antibody after implantation of pellets consisting of rhBMP-2 and collagen in rat calf muscle pouch. On day 3 after implantation, BMP was detected in the entire lump, and the intensity of staining for BMP around the implant on day 7 was weaker than that on day 3. The staining for BMP decreased with time and the region of staining for BMP remained more centralized in the implant. On day 10 after implantation, BMP was observed in part of the newly induced cartilage, especially around chondrocytes. On day 14 after implantation, BMP was localized in the newly induced woven bone. On day 21, BMP staining was found in osteoblasts at the surface of the newly induced bone. Especially, the staining for BMP decreased from day 10 to day 21. These results indicate that the woven bone was replaced with mature lamellar bone from day 14 to day 21. The present findings suggest that rhBMP-2 plays an important role in osteoinduction, especially at the early stage.     

Molded bone augmentation by a combination of barrier membrane and recombinant human bone morphogenetic protein-2

OBJECTIVES: To provide the histological background to a new method of local bone augmentation, we examined the events occurring beneath a barrier membrane applied with recombinant human bone morphogenetic protein-2 (rhBMP-2). MATERIALS AND METHODS: The effects on bone augmentation of rhBMP-2, applied with a membrane mold (BMP-Memb), over surgically-induced bone defects in rat calvaria were examined histologically, and the results compared with those from application of rhBMP-2 (BMP) alone, or of a molded membrane (Memb) alone. RESULTS: At postoperative week 2, the BMP group showed the most marked bone formation. However, the bone diminished in size by week 8. The Memb group showed slow but continuous bone formation by week 8. In the BMP-Memb group, bone filled the space in the mold at week 2, and this was maintained until week 8. Moreover, the soft tissue that had intervened between newly formed bone and the membrane in the Memb group was not evident in the BMP-Memb group, in which bone had formed directly on the membrane. CONCLUSIONS: The results suggest that the combination of rhBMP-2 and barrier membrane has advantages in producing and maintaining bone in the intended shape by inducing osteoblasts directly on the inner surface of the membrane.     

Histologic and clinical evaluation for maxillary sinus augmentation using macroporous biphasic calcium phosphate in human

Objectives: This study evaluated both the clinical and histological aspects of bone formation in maxillary sinus augmentation using MBCP as the bone-grafting material.
Material and methods: MBCP was used as a primary bone substitute for maxillary sinus augmentation. Fifty-two patients were selected after a medical and dental examination, and were divided into the following three groups: those augmented with MBCP only; MBCP combined with irradiated cancellous bone; and MBCP combined with intraoral autogenous bone. After a healing period (average 6.78 months after surgery), bone cores were harvested for a histological evaluation and the implant fixtures were installed. These bone cores were evaluated via light microscope and implants were followed up for at least six months after loading.
Results: Four to ten months after surgery, new vital bone surrounding the MBCP particles was observed in 18 bone biopsies. Two out of the 130 implants installed were explanted due to a failure of osseointegration before the prosthetic procedure. All the remaining implants were functioning for 6 to 27 months (average 12.96 months). The cumulative survival rate of the implants was 98.46%.
Conclusion: These results show that MBCP can be used as a grafting material for sinus floor augmentation, whether combined with other bone graft materials or not, and lead to a predictable prognosis for dental implants in the posterior maxillary area where there is insufficient vertical height for fixture installation.     

Peri-implant bone regeneration using recombinant human bone morphogenetic protein-2 in a canine model: a dose-response study

The objective of this study was to evaluate the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) dose on alveolar ridge augmentation and dental implant osseointegration. Bilateral, 5 mm supraalveolar, peri-implant defects were surgically created in 6 beagle dogs. rhBMP-2 (0.05, 0.1 or 0.2 mg/ml) in an absorbable collagen sponge (ACS) carrier was molded around the fixtures and wounds were closed. Treatment variations were alternated between animals (incomplete block design). Animals were sacrificed at week 8 postsurgery. Nine of twelve jaw quadrants healed uneventfully. Two jaw quadrants exhibited wound failure by week 4 and one by week 8 postsurgery. Radiographic bone regeneration was observed in defects without wound failure from week 4 postsurgery. Radiolucent voids of variable size and shape were observed and regressed over time. In weeks 6 through 8, there was an apparent increase in bone density and trabecular structure, while bone height and volume decreased. Histometric analysis revealed limited differences in bone regeneration between experimental conditions. Bone regeneration area averaged (+/- SD) 1.0 +/- 0.5, 3.5 +/- 1.4 and 2.3 +/- 0.4 mm2 for the 0.05, 0.1 and 0.2 mg/ml dose, respectively. There were no significant differences in osseointegration. Osseointegration in newly formed bone averaged 19 +/- 4%, 18 +/- 10% and 21 +/- 6% for the 0.05, 0.1 and 0.2 mg/ml rhBMP-2 sites, respectively. Collectively, the data suggest that there are no dramatic differences in bone induction and osseointegration within the selected dose and observation interval.     

Enhanced vertical alveolar bone augmentation by recombinant human bone morphogenetic protein-2 with a carrier in rats

This study aimed to evaluate the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) on vertical bone regeneration of edentulous ridge. Bilateral upper first and second molars of 8-week-old Wistar rats were extracted and the ridges were allowed to heal for 3 weeks. Compressed poly(lactic-co-glycolic acid) copolymer/gelatin sponge (PGS) was used as a carrier of rhBMP-2. PGS alone (control group) or PGS with 5 mug rhBMP-2 (test group) was implanted at the top part of alveolar ridge. The sham group received no implantation. The rats were killed at 1, 2, 4, 8 and 12 weeks after implantation and examined histologically and histomorphometrically. In the test group, significant bone augmentation was evident on the alveolar ridge throughout the experimental period. Histomorphometric analysis revealed greater tissue volume and height of alveolar bone in the test group compared with the control and sham groups (P < 0.05) from 4 weeks onward and the augmented tissues (5 mm3 in tissue volume and 1.5 mm in bone height) were maintained until 12 weeks. Osteoblast surface increased at 2 and 4 weeks and osteoid thickness reached a peak (25 microm) at 2 weeks. Dynamic variables, which represented calcification, were higher in the test group than the control and sham groups at 4 and 8 weeks (P < 0.05). These results suggest that use of rhBMP-2/PGS may achieve vertical bone augmentation, and stabilizes denture prosthesis or makes up for inadequate bone mass for implant prosthesis.     

Effect of aging on bone formation induced by recombinant human bone morphogenetic protein-2 combined with fibrous collagen membranes at subperiosteal sites

This study was designed to examine the effect of aging on bone formation induced by recombinant human bone morphogenetic protein-2 (rhBMP-2) combined with a fibrous collagen membrane (FCM). Implantation was done subperiosteally in bilateral palatal grooves in 34 male Wistar rats divided into three age groups: a 10-week-old group (10w group), a 30-week-old group (30w group) and a 70-week-old group (70w group). RhBMP-2-combined FCMs were implanted on the left palatal grooves as BMP-implanted sites (BMP site), while rhBMP-2 was not implanted on the right palatal grooves as control sites. The rats were sacrificed 6 weeks after implantation, and histometric evaluations were performed. New bone formation was observed in every site of each age group and the new bone was almost completely continuous with the original bone. The new bone volume (NBV) of the BMP site was significantly higher than that of the control site in each age group. The NBV of both the control and BMP sites were highest in the 10w group and lowest in the 70w group. The disparity of NBV between the control and BMP sites, which indicated the response to implanted BMP excluding the effect of skeletal growth and surgical stimulation, did not significantly differ among the age groups. These results indicate that rhBMP-2-combined FCM has the ability to induce new bone formation continuous with original bone even in senescent rats. Furthermore, it appeared that, in the case of palatal subperiosteal implantation, the responsiveness to implanted BMP was independent of age, although the total volume of newly formed bone declined with aging.     

重组人血管内皮生长因子和重组人骨形态发生蛋白-7对大鼠成骨细胞增殖能力的影响

目的研究重组人血管内皮生长因子（recombinant human vascular endothelial growth factor,rhVEGF）和重组人骨形态发生蛋白-7（recombinant human bone morphogenetic protein-7,rhBMP-7）对成骨细胞增殖能力的影响。方法取大鼠颅盖骨组织块,采用改良组织块混合酶消化法培养成骨细胞,分成4组,第1组、第2组、第3组分别加3．125ng／mL不含血清的rhVEGF培养液、50．000ng／mL不含血清的rhBMP-7培养液、3．125ng／mL不含血清的rhVEGF和50．000ng／mL不含血清的rhBMP-7培养液,第4组加不含血清的培养液作为对照组,采用细胞培养技术,应用光镜、四甲基偶氮唑盐（methyl thiazolyl tetrazotium,MTT）法,分析不同浓度的rhVEGF和rhBMP．7对成骨细胞增殖的影响。结果与对照组相比,3．125ng／mL rhVEGF和50.000ng／mLrhBMP-7单独或者联合作用,在1、3、5d均有促进细胞增殖的作用,与对照组的差异均有统计学意义（P〈0.05）,各组间比较差异也有统计学意义（P〈0．05）。其中,3．125ng／mLrhVEGF和50．000ng／mL rhBMP-7单独或者两者联合作用于第3天时,成骨细胞增殖最显著。结论一定剂量的rhVEGF和rhBMP-7可明显促进成骨细胞的增殖。     

The effect of fibroblast growth factor-2 on the osteoinductive activity of recombinant human bone morphogenetic protein-2 in rat muscle

To clarify the effect of recombinant human basic fibroblast growth factor (FGF-2) on the osteoinductive activity of recombinant human bone morphogenetic protein-2 (BMP-2) in vivo, different amounts of FGF-2 (0, 16, 80 and 400 ng, and 2, 10 and 50 micro g: n=10 in each group), BMP-2 (2 micro g) and type I collagen as a carrier were mixed and implanted into rat calf muscles. Three weeks after implantation, compared with the controls, the radiopaque shadows of the implants were increased in the 16, 80 and 400 ng FGF-2-treated groups, but decreased in the 2, 10 and 50 micro g FGF-2-treated groups. In addition, alkaline phosphatase activity was increased in the 16, 80 and 400 ng FGF-2-treated groups but decreased in the 50 micro g FGF-2-treated group. Histological examination revealed increased bone formation in the 16, 80 and 400 ng FGF-2-treated groups. These results show that combined treatment with FGF-2 and BMP-2 has a biphasic effect on osteoinductive activity, i.e. it increases with low doses of FGF-2 and decreases with high doses of FGF-2.     

胰岛素样生长因子-Ⅰ和骨形态发生蛋白-2对人牙周膜细胞增殖的作用

目的：重组人胰岛素样生长因子－Ｉ（ｒｈＩＧＦ－Ｉ）、重组人骨形态发生蛋白－２（ｒｈＢＭＰ－２）分别或联合应用对人牙周膜（ＰＤＬ）细胞增殖的影响。方法：采用组织块法体外培养人ＰＤＬ细胞,ＭＴＴ法测定ＰＤＬ细胞在不同生长因子刺激下的增殖情况。结果：ｒｈＩＧＦ－Ｉ、ｒｈＢＭＰ－２都可促进人ＰＤＬ细胞的增殖,这种促增殖作用呈一定的浓度依赖性,ｒｈＩＧＦ－Ｉ与ｒｈＢＭＰ－２联合应用对人ＰＤＬ细胞的增殖有协同作用,且与单独应用相比相差显著。结论：ｒｈＩＧＦ－Ｉ、ｒｈＢＭＰ－２可望作为牙周再生的生物活性介质,ｒｈＩＧＦ－Ｉ与ｒｈＢＭＰ－２联合应用对ＰＤＬ细胞的促增殖作用更强。     

Cyclooxygenase-2 inhibitor reduces simvastatin-induced bone morphogenetic protein-2 and bone formation in vivo

BACKGROUND AND OBJECTIVE: Simvastatin, a cholesterol-lowering drug, also stimulates oral bone growth when applied topically, without systemic side-effects. However, the mechanisms involved in vivo are not known. We hypothesized that bone morphogenetic protein-2, nitric oxide synthase, and cyclooxygenase-2 are involved, based on prior in vitro evidence. MATERIAL AND METHODS: A rat bilateral mandible model, where 0.5 mg of simvastatin in methylcellulose gel was placed on one side and gel alone on the other, was used to quantify nitric oxide, cyclooxygenase-2 and bone morphogenetic protein-2 (via tissue extraction, enzyme activity or immunoassay), and to analyze the bone formation rate (via undecalcified histomorphometry). Cyclooxygenase-2 and nitric oxide synthase inhibitors (NS-398 and L-NAME, respectively) were administered intraperitoneally. RESULTS: Simvastatin was found to stimulate local bone morphogenetic protein-2, nitric oxide and the regional bone formation rate (p < 0.05), whereas NS-398 inhibited bone morphogenetic protein-2 and reduced the bone formation rate (p < 0.05). CONCLUSION: These data suggest an association between simvastatin-induced bone morphogenetic protein-2 and bone formation in the mandibular microenvironment, and the negative effect of cyclooxygenase-2 inhibitors on bone growth.     

原核表达重组人骨形态发生蛋白-7对牙槽骨修复再生的实验研究

目的研究原核表达重组人骨形态发生蛋白- 7（rhBMP- 7）对牙槽骨修复再生的影响。方法采用新西兰白兔建立动物模型,以明胶海绵作为载体,将大肠杆菌原核表达的rhBMP- 7与之复合后植入即刻拔除牙齿的牙槽窝内进行干预治疗,术后2、4、8及12周处死动物,取标本进行大体观察、扫描电镜分析、碱性磷酸酶（ALP）活性测定。结果大体观察结果显示,实验组和对照组牙槽嵴高度的吸收差异有显著性;扫描电镜观测显示,实验组的骨创愈合比对照组大约提前4～6周;ALP活性测定显示实验组均明显高于对照组,其差异有统计学意义（P<0.05）。结论原核表达rhBMP- 7具有促进新骨修复再生、防止牙槽骨吸收的作用。     

Alveolar ridge augmentation using implants coated with recombinant human bone morphogenetic protein-2: radiographic observations

Objectives: Effective carrier technologies and dosing appear critical for the successful use of bone morphogenetic proteins (BMPs). This study evaluated radiographically the potential of a purpose‐designed titanium porous‐oxide implant surface combined with recombinant human BMP‐2 (rhBMP‐2) to stimulate alveolar ridge augmentation. Material and methods: Twelve young‐adult Labrador dogs were used. Three 10‐mm titanium implants per jaw quadrant were placed 5 mm into the alveolar ridge following extraction of the premolar teeth and reduction of alveolar ridge. Six animals received implants coated with rhBMP‐2 at 0.75 or 1.5 mg/ml randomized to contralateral jaw quadrants. Another six animals received implants coated with rhBMP‐2 at 3 mg/ml or uncoated control using the same split‐mouth design. The mucoperiosteal flaps were advanced, adapted, and sutured to submerge the implants. Radiographic registrations were made immediately postsurgery (baseline), and at weeks 4 and 8 (end of study). Results: rhBMP‐2‐coated implants exhibited robust radiographic bone formation extending to and above the implant platform from week 4 (P<0.01). Some rhBMP‐2‐coated implants showed voids within the newly formed bone that gradually resolved and/or implant displacement, being severe in two animals receiving implants coated with rhBMP‐2 at 3 mg/ml. Controls showed limited, if any, new bone formation at weeks 4 and 8 postsurgery. There were no significant differences among the rhBMP‐2 groups in bone gain. Conclusions: The titanium porous‐oxide surface serves as an effective carrier for rhBMP‐2, showing a clinically significant potential to stimulate local bone formation. With the carrier technology used, therapeutic dosage appears to be in the range of 0.75–1.5 mg/ml.     

Effect of recombinant human bone morphogenetic protein-2 on bone regeneration and osseointegration of dental implants

Recombinant human bone morphogenetic protein-2 (rhBMP-2) induced bone regeneration and osseointegration was evaluated in bony defects created within the hollow chamber of endosseous dental implants in 14 foxhound dogs. Bilateral extractions of mandibular premolars were performed and surgical implantation of 104 hollow cylinder implants followed after 8 weeks of healing. Experimental implants had their hollow chamber filled with 20 microg of rhBMP-2 delivered with a bovine collagen carrier, whereas the control implants had their apical chamber left empty. Dogs were followed for 2, 4, 8 and 12 weeks. Histomorphometric evaluation and immunohistochemical analysis were performed. Minimal bone was regenerated at 2 weeks for both groups. At 4 weeks, bone fill averaged 23.48% for the rhBMP-2 and 5.98% for the control group (P<0.05). At 8 weeks, mean bone fill was 20.94% and 7.75% for the rhBMP-2 and the controls, respectively (P<0.05). At 12 weeks, mean bone fill was 31.39% and 24.31% for the rhBMP-2 and control implants, respectively (P>0.05). Bone-implant contact (BIC) increased for both groups over time and at 8 weeks the rhBMP-2 BIC value was 18.65% and for the control 7.22% (P<0.05). At 12 weeks, the BIC was 43.78% and 21.05% for the rhBMP-2 and the control group, respectively (P<0.05). Immunohistochemical staining for type II collagen was positive only for parts of the collagen carrier and formation of cartilaginous intermediate was not observed in any of the specimens. The results suggest that, in confined defects adjacent to dental implants, rhBMP-2 can induce bone regeneration in close apposition to the implant surface.