Ultrasonic evaluation of dental implant osseointegration (original) (raw)

Influence of healing time on the ultrasonic response of the bone-implant interface

2012

The aim of the present study is to investigate the effect of bone healing on the ultrasonic response of coin-shaped titanium implants inserted in rabbit tibiae. The ultrasound response of the interface was measured in vitro at 15 MHz after 7 and 13 weeks of healing time. The average value of the ratio r between the amplitudes of the echo of the bone-implant interface and of the water-implant interface was determined. The bone-implant contact (BIC) was measured by histomorphometry and the degree of mineralisation of bone was estimated qualitatively by histologic staining. The significant decrease of the ultrasonic quantitative indicator r (p 5 2.10 24) vs. healing time (from r 5 0.53 to r 5 0.49) is explained by (1) the increase of the BIC (from 27% to 69%) and (2) the increase of mineralization of newly formed bone tissue, both phenomena inducing a decrease of the gap of acoustical impedance.

Proposal for an Ultrasonic Tool to Monitor the Osseointegration of Dental Implants

Sensors, 2007

The longevity of dental implants depends on osseointegration, which provides load-bearing capacity without putting the prosthesis at risk from micromotions at the implant-bone interface. This research involved an analysis of the viability of an ultrasonic evaluation tool to quantify osseointegration. Ultrasonic transmission is directly dependent on the difference between the acoustic impedance of materials in intimate contact with each other. The closer their acoustic impedances the more intense their transmission. Therefore, an analysis of the ultrasonic echoes would presumably allow for a quantitative evaluation of the bone tissue that has grown into the pores of the implant. In addition, the literature reports that bone fracture healing can be accelerated by the application of a controlled low-amplitude mechanical stimulus on the site of the lesion. In fact, acoustic pressure waves of low-intensity pulsed ultrasound are reportedly a secure technique for promoting mechanical stimulus without impairing the healing process. Many experimental and clinical trials have confirmed that daily transcutaneous ultrasound applications on the injured site are beneficial to the enhancement of fractured bone. This proposal aims to bring together the characteristics of ultrasound propagation and the positive effect of ultrasound on bone growth into a single tool that quantitatively monitors the evolution of the osseointegration process. The viability of a device with these features was investigated through simulations and experimentally. The initial simulations were conducted to explore the influence of waveguide shapes on the tool's sensitivity to changes in the implant supporting media. The waveguides were designed in two parts, one consisting of a screwshaped part to attach to the implant and the other a conical or step-shaped part to which the Sensors 2007, 7 1225 ultrasonic source was fixed in the first simulations. The step-shaped waveguide proved to be the more sensitive; intermediate stages of the osseointegration process were simulated and experiments were conducted with the step-shaped aluminum waveguide attached to a cylindrical aluminum nut embedded at different depths, so that the results obtained were only due to lateral attachment of the parts. These devices indicated that the transmission of ultrasound through the lateral surface of the implant by dilatational waves could render this tool suitable for monitoring the osseointegration of dental implants.

Ultrasonic Evaluation of Dental Implant Biomechanical Stability: An In Vitro Study

Ultrasound in Medicine & Biology, 2011

Dental implants are widely used for oral rehabilitation. However, there remain risks of failure that are difficult to anticipate. The objective of this ex vivo study is to investigate the potentiality of quantitative ultrasound (QUS) to assess the amount of bone in contact with titanium prototype cylindrical implants. Four groups of 10 rabbit femurs each are considered, corresponding to different amounts of bone in contact with the implant. The 10 MHz ultrasonic response of the implant is processed to derive a quantitative indicator I, based on the temporal variation of the signal amplitude. Analysis of variance (ANOVA) (p < 10(-5)) tests revealed a statistical distribution of I significantly correlated with the amount of bone in contact with the cylinders. An analytical model considering the propagation of lateral waves allows the understanding of the physical origin of the echoes. QUS technique may be used to investigate the amount of bone in contact with a cylinder implant.

Dental implantation: ultrasound transmission velocity to evaluate critical bone quality--an animal model

Ultraschall in der Medizin (Stuttgart, Germany : 1980), 2008

In dental implantology, preoperative evaluation of bone quality is an important aspect for the long-term success of the treatment. The insertion of implants into regions with a great portion of poorly mineralised cancellous bone, in particular, increases the risk of subsequent implant failure. The measurement of Ultrasound Transmission Velocity (UTV) proved to be a non-invasive and valid method for the assessment of mechanical properties of bone. The aim of this study was to correlate conventional histomorphometric bone properties with UTV-values from mandibular and iliac crest bone specimens in an animal model. 12 native (no sample preparation) porcine specimens from mandibular bone and 14 from iliac crest bone, respectively, were studied both by UTV measurement and by conventional histomorphometry. UTV-values were measured bicortically by three different investigators four times at each site. Bone samples from identical sites were obtained and ground down to a thickness of approx....

In vivo monitoring of implant osseointegration in a rabbit model using acoustic sound analysis

Journal of Orthopaedic Research, 2014

Implant osseointegration can currently only be assessed reliably post mortem. A novel method that relies on the principle of acoustic sound analysis was developed to enable examination of the longitudinal progress of osseointegration. The method is based on a magnetic sphere inside a hollow cylinder of the implant. By excitation using an external magnetic field, collision of the sphere inside the implant produces a sound signal. Custom-made titanium implants equipped thusly were inserted in each lateral femoral epicondyle of 20 New Zealand White Rabbits. Two groups were investigated: Uncoated, machined surface versus antiadhesive surface; and calcium phosphate-coated surface versus antiadhesive surface. The sound analysis was performed postoperatively and weekly. After 4 weeks, the animals were euthanized, and the axial pull-out strengths of the implants were determined. A significant increase in the central frequency was observed for the loose implants (mean pull-out strength 21.1 AE 16.9 N), up to 6.4 kHz over 4 weeks. In comparison, the central frequency of the osseointegrated implants (105.2 AE 25.3 N) dropped to its initial value. The presented method shows potential for monitoring the osseointegration of different implant surfaces and could considerably reduce the number of animals needed for experiments.

Evaluation of Dental Implant Osseointegration Using Ultrasonic Spectrometry : A Phantom Study

WSEAS Transactions on Signal Processing archive, 2014

One of the challenging and important problems that still needs solution within the field of dental implant surgery is to monitor the osseointegration process. Therefore, this work aims to achieve a reliable noninvasive automatic method to evaluate dental implant stability which is directly related to the grade of osseointegration. For this purpose, an experimental phantom study was performed to simulate this process and evaluate it. Ultrasonic spectrometry was proposed and used to take measurements that were processed and analyzed to estimate the stability of the simulated dental implant. The phantom that was designed and used in the experiments simulated a jawbone with a dental implant and was made of a little pool filled with soft-tissueequivalent material (with respect to ultrasound waves) and a solid cylinder of fresh oak-wood immersed into it to simulate the jawbone. A metal screw was used to simulate the dental implant. By screwing this screw into or out of the wooden cylinder, varying grades of stiffness and contact between the screw and the wooden tissues were obtained. And by this way, varying screw stability grades which simulate varying osseointegration grades were achieved. Pulse-echo ultrasound was used to measure the power spectra of the received ultrasonic echosignals. These power spectra were, at first, processed and normalized then analyzed by using the partial least squares method to estimate the corresponding implant stability or stiffness grades. The number of screwing turns (for the screw into or out of the wooden cylinder) was used as a measure of stiffness grade.The feasibility of this approach was investigated through experimental tasks and promising results were achieved. A coefficient of determination R 2 of 96.4% and a mean absolute error of ±0.23 screwing turns were achieved when comparing real and estimated stiffness-grade values, indicating the high efficiency and good accuracy of this approach.

Ultrasound imaging of dental implants

Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2012

Accurate measurement of soft tissue thickness is needed prior to dental implant placement and prior to surgical uncovering of the implant. Ultrasonography has many potential advantages for use in dental implant surgery, but has not yet been made suitable for clinical use. A 2D ultrasound imaging system and a mechanical positioning system were used to scan dental implants embedded in a porcine jaw, covered by soft tissue, submerged in a water tank. Results indicated that ultrasound can be used to accurately detect, locate, and measure dental implant fixtures and measure the thickness of the overlying soft tissue in an ex vivo environment.

Influence of Resonance Frequency Analysis (RFA) Measurements for Successful Osseointegration of Dental Implants During the Healing Period and Its Impact on Implant Assessed by Osstell Mentor Device

Open Access Macedonian Journal of Medical Sciences

AIM: This study aimed to investigate and assess primary and secondary dental implant stability during the osseointegration period. METHODS: A total of 77 implants were placed in 42 patients with 26 males and 16 females. The study was conducted by comparing the resonance frequency analysis (RFA) values of the implants inserted in the lower jaw. RFA was done immediately after implant insertion and after 12 weeks. Results were statistically evaluated using SPSS Statistics for Windows, Version 7.1. Level of significance was set at P < 0.05. RESULTS: Significant differences were detected between the primary and secondary stability values, respectively. Maximum RFA value of 88 and the minimum value of 52 were observed. Stability values increased during the following three months, and all implants were successfully integrated without complication. CONCLUSION: Our results indicate and suggest that there is a strong linear correlation between implant stability and ISQ values that can be d...