The biological response to three different nanostructures applied on smooth implant surfaces

Objective: To evaluate the biological effects of three calcium phosphate (CaP) coatings with nanostructures on relatively smooth implant surfaces. Material and methods: Stable CaP nanoparticle suspensions of different particle sizes and structures were coated onto implants by immersion and subsequent heat treatment. An uncoated implant was used as the control. After topographical and chemical characterizations, implants were randomly inserted into rabbit tibiae for removal torque (RTQ) testing. To confirm the biological reaction, implants were placed in the bilateral femurs of three rabbits. Results: The topographical characterization showed that each surface had different nanostructural characteristics and X‐ray photon spectroscopy showed various CaP compositions. The control and test groups had different nanotopographies; however, the differences among the test groups were only significant for Surfaces B and C and the rest were insignificant. The RTQ tests showed significantly higher values in two test groups (Surface A and Surface C). Histologically, no adverse effects were seen in any group. Histomorphometrical evaluation showed comparable or better osseointegration along the implant threads in the test groups. Conclusion: The three different CaP coatings with nanostructures on the implant surfaces had enhancing effects on osseointegration. Along with the surface nanotopography, the CaP chemistry might have influenced the biological outcomes.     

The influence of alendronate on osseointegration of nanotreated dental implants in New Zealand rabbits

Objectives: Growing clinical demands for stronger and faster bone bonding to the implant have motivated the development of methods enhancing osseointegration. Lately, the application of bisphosphonates (bis) in order to optimize bone healing has become a topic of great interest. N‐containing bis, such as alendronate (ALN), are the more potent drugs of this class. It was the aim of this study to determine the effect of ALN on the osseointegration of a well‐documented nanotreated implant system in a rabbit femoral condyle model. Material and methods: Thirty‐two adult female New Zealand White rabbits received one implant (3.25 mm in diameter and 10 mm in length) in their left femoral condyle, a week after they were ovariectomized. Half of them were saline treated (control, group A) and the other half were ALN treated (group B). Rabbits from both groups were euthanized after 6 and 12 weeks, respectively. Results: The specimens were evaluated histologically and histomorphometrically. Upon histological evaluation, no obvious differences were found between the control and the treatment group. Implants showed good integration into the bone tissue surrounding them. There were also no statistically significant differences in bone‐to‐implant contact and the amount of bone tissue in the immediate neighborhood of the implant at both healing periods. Conclusions: The systemic administration of ALN was not found to affect histological osseointegration of implants in animals with a hormonal status resembling that of postmenopausal healthy women. Further research will be needed to investigate this approach.     

Biofunctionalization of titanium implants with a biomimetic active peptide (P‐15) promotes early osseointegration

Objectives: The early stages of peri‐implant bone formation play an essential role in the osseointegration and long‐term success of dental implants. By incorporating bioactive coatings, this biofunctionalization of implant surfaces may enhance the attachment of the implant to the surrounding bone and stimulate bone regeneration. Material and methods: To demonstrate faster osseointegration, the surfaces of dental implants were grit‐blasted and acid‐etched. They were then coated with hydroxyapatite (HA) and experimental implants were further coated with a biomimetic active peptide (P‐15) in one of two concentrations. These biofunctionalized samples and controls with no peptide were placed in the forehead region of 12 adult pigs. Six animals were evaluated for a period of 14 or 30 days. Results: Histomorphometric analysis demonstrated that the implants with the high concentration of P‐15 had significantly higher percentage of bone‐to‐implant contact (BIC) at 14 (P=0.018) and 30 (P=0.015) days compared with the other groups. Both concentrations of P‐15 showed increased peri‐implant bone density compared to the control group at 30 days. Conclusion: Biofunctionalization of the implant surface with a biomimetic active peptide leads to significantly increased BIC rates at 14 and 30 days and higher peri‐implant bone density at 30 days. To cite this article:
Lutz R, Srour S, Nonhoff J, Weisel T, Damien CJ, Schlegel KA. Biofunctionalization of titanium implants with a biomimetic active peptide (P‐15) promotes early osseointegration.
Clin. Oral Impl. Res. 21 , 2010; 726–734.
doi: 10.1111/j.1600‐0501.2009.01904.x     

Influence of implant diameter on surrounding bone

OBJECTIVES: Implant osseointegration is dependent upon various factors, such as bone quality and type of implant surface. It is also subject to adaptation in response to changes in bone metabolism or transmission of masticatory forces. Understanding of long-term physiologic adjustment is critical to prevention of potential loss of osseointegration, especially because excessive occlusal forces lead to failure. To address this issue, wide-diameter implants were introduced in part with the hope that greater total implant surface would offer mechanical resistance. Yet, there is little evidence that variation in diameter translates into a different bone response in the implant vicinity. Therefore, this study aimed at comparing the impact of implant diameter on surrounding bone. MATERIAL AND METHODS: Twenty standard (3.75 mm) and 20 wide (5 mm) implants were placed using an animal model. Histomorphometry was performed to establish initial bone density (IBD), bone to implant contact (BIC) and adjacent bone density (ABD). RESULTS: BIC was 71% and 73%, whereas ABD was 65% and 52%, for standard and wide implants, respectively. These differences were not statistically different (P>0.05). Correlation with IBD was then investigated. BIC was not correlated with IBD. ABD was not correlated to IBD for standard implants (r2=0.126), but it was correlated with wide implants (r2=0.82). In addition, a 1 : 1 ratio between IBD and ABD was found for wide implants. It can be concluded, within the limits of this study, that ABD may be influenced by implant diameter, perhaps due to differences in force dissipation.     

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对患者进行种植修复时,上下颌骨种植区垂直向和(或)水平向骨质的吸收,无疑给医生提出了一个难题。为确保种植区符合种植条件,必要的剩余牙槽骨尤为重要。本文对近年来改善颌骨种植区骨量不足的外科手术技术及其研究进展进行综述,为临床操作提供帮助。