Development of Implant/Interconnected Porous Hydroxyapatite Complex as New Concept Graft Material

Abstract

BackgroundDental implant has been successfully used to replace missing teeth. However, in some clinical situations, implant placement may be difficult because of a large bone defect. We designed novel complex biomaterial to simultaneously restore bone and place implant. This complex was incorporated implant into interconnected porous calcium hydroxyapatite (IP-CHA). We then tested this Implant/IP-CHA complex and evaluated its effect on subsequent bone regeneration and implant stability in vivo.Methodology/Principal FindingsA cylinder-type IP-CHA was used in this study. After forming inside of the cylinder, an implant was placed inside to fabricate the Implant/IP-CHA complex. This complex was then placed into the prepared bone socket in the femur of four beagle-Labrador hybrid dogs. As a control, implants were placed directly into the femur without any bone substrate. Bone sockets were allowed to heal for 2, 3 and 6 months and implant stability quotients (ISQ) were measured. Finally, tissue blocks containing the Implant/IP-CHA complexes were harvested. Specimens were processed for histology and stained with toluidine blue and bone implant contact (BIC) was measured. The ISQs of complex groups was 77.8±2.9 in the 6-month, 72.0±5.7 in the 3-month and 47.4±11.0 in the 2-month. There was no significant difference between the 3- or 6-month complex groups and implant control groups. In the 2-month group, connective tissue, including capillary angiogenesis, was predominant around the implants, although newly formed bone could also be observed. While, in the 3 and 6-month groups, newly formed bone could be seen in contact to most of the implant surface. The BICs of complex groups was 2.18±3.77 in the 2-month, 44.03±29.58 in the 3-month, and 51.23±8.25 in the 6-month. Significant difference was detected between the 2 and 6-month.Conclusions/SignificanceWithin the results of this study, the IP-CHA/implant complex might be able to achieve both bone reconstruction and implant stability.

A stability evaluation of a novel titanium dental implant/interconnected porous hydroxyapatite complex under functional loading conditions

“…In the present results, the ISQ of an implant/IP-CHA complex placed in a mandible after 6 months of healing was over 60. The values are compatible with those in a previous study 13) . On the other hand, those in the control implant group were observed to be 70 or more, and significant differences were observed with respect to the test group.…”

“…To evaluate the osseointegration of the implant/IP-CHA complex, implant stability and the BIC ratio were measured. A previous study demonstrated that placing an implant/IP-CHA complex in the femur resulted in ISQ and BIC values as successful as those of the control implants that were placed in the preexisting bone 13) . ISQ measurements using a RFA have been shown to be an effective method of measuring implant stability [17][18][19] .…”

“…The implant/IP-CHA complex was fabricated in accordance with a previous study 13) . Briefly, the implant screw thread was prepared at the inner surface of a hollow cylinder of IP-CHA using a special electric engine (Nobel Biocare Japan, Tokyo, Japan) with serial cutting drills and a screw tap; then, countersinking was performed in the upper section.…”

“…Measurements were performed three times from two different directions, and the values obtained for each implant were averaged. The ISQ measurements were carried out according to previous studies 13,14) .…”

“…Specifically, the implant/IP-CHA complex consists of a dental implant fixture surrounded by a block of IP-CHA. Our previous study results demonstrated that an implant/IP-CHA complex could simultaneously achieve superior osteoconduction and implant stability 13) . Osseointegration could be detected at the bone-implant interface with the implant/IP-CHA complex after 6 months.…”