scholarly journals In vivo assessment of the effect of controlled high- and low-frequency mechanical loading on peri-implant bone healing

2012 ◽  
Vol 9 (72) ◽  
pp. 1697-1704 ◽  
Author(s):  
Xiaolei Zhang ◽  
Katleen Vandamme ◽  
Antonia Torcasio ◽  
Toru Ogawa ◽  
G. Harry van Lenthe ◽  
...  
Keyword(s):  
Mechanical Loading ◽  
Bone Healing ◽  
Ex Vivo ◽  
Low Frequency ◽  
Constant Strain Rate ◽  
Titanium Implants ◽  
Cortical Level ◽  
Bone Response ◽  
Custom Made ◽  
40 Hz

The aim of this study was to investigate the effect of controlled high- (HF) and low-frequency (LF) mechanical loading on peri-implant bone healing. Custom-made titanium implants were inserted in both tibiae of 69 adult Wistar rats. For every animal, one implant was loaded by compression through the axis of tibia (test), whereas the other one was unloaded (control). The test implants were randomly distributed among four groups receiving different loading regimes, which were determined by ex vivo calibration. Within the HF (40 Hz) or LF (2 Hz) loading category, the magnitudes were chosen as low- (LM) and high-magnitude (HM), respectively, leading to constant strain rate amplitudes for the two frequency groups. This resulted in the four loading regimes: (i) HF-LM (40 Hz–0.5 N); (ii) HF-HM (40 Hz–1 N); (iii) LF-LM (2 Hz–10 N); and (iv) LF-HM (2 Hz–20 N) loading. Loading was performed five times per week and lasted for one or four weeks. Tissue samples were processed for histology and histomorphometry (bone-to-implant contact, BIC; and peri-implant bone fraction, BF) at the cortical and medullar level. Data were analysed statistically with ANOVA and paired t -tests with the significance level set at 0.05. For the one-week experiments, an increased BF adjacent to the implant surface at the cortical level was exclusively induced by the LF-HM loading regime (2 Hz–20 N). Four weeks of loading resulted in a significant effect on BIC (and not on BF) in case of HF-LM loading (40 Hz–0.5 N) and LF-HM loading (2 Hz–20 N): BIC at the cortical level significantly increased under both loading regimes, whereas BIC at the medullar level was positively influenced only in case of HF-LM loading. Mechanical loading at both HF and LF affects osseointegration and peri-implant BF. Higher loading magnitudes (and accompanying elevated tissue strains) are required under LF loading to provoke a positive peri-implant bone response, compared with HF loading. A sustained period of loading at HF is needed to result in an overall enhanced osseointegration.

scholarly journals Influence of the Thermal Treatment to Address a Better Osseointegration of Ti6Al4V Dental Implants: Histological and Histomorphometrical Study in a Rabbit Model

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Antonio Scarano ◽  
Ezio Crocetta ◽  
Alessandro Quaranta ◽  
Felice Lorusso
Keyword(s):  
Thermal Treatment ◽  
Dental Implants ◽  
Bone Healing ◽  
Rabbit Model ◽  
Titanium Implants ◽  
Control Group ◽  
Left Femur ◽  
Bone Response ◽  
First Choice ◽  
Significant Difference

Background. Pure titanium continues to be the first choice for dental implants and represents the gold standard for their biocompatibility and physical and mechanical characteristics, while the titanium alloy (Ti6Al4V) has good mechanical properties. The surface structure of the titanium oxide layer formation on the surface influences and improves the bone response around dental implants. Purpose. The purpose of this study is to evaluate the influence of a thermal treatment of Ti6Al4V implant surfaces and the bone healing response in a rabbit model. Methods. Altogether sixteen implants with same design were inserted into the distal femoral metaphysis. A screw (13 mm long, 4 mm in diameter) was inserted in an implant bed. Each rabbit received two implants, one in the left femur and one in the right femur. The samples were histologically and histomorphometrically evaluated at 8 weeks. Results. A statistically significant difference (p = 0.000034) was present histologically in the percentages of bone-implant contact (BIC) between the test group (BIC = 69.25±4.49%.) and control group (BIC = 56.25 ± 4.8%) by one-way analysis of variance (ANOVA). Significance was set at p ≤ 0.05. Conclusions. The outcome of the present study indicates a novel approach to improving bone healing around titanium implants.

Caffeine potentiates low frequency skeletal muscle force in habitual and nonhabitual caffeine consumers

2000 ◽  
Vol 89 (5) ◽  
pp. 1719-1724 ◽  
Author(s):  
Mark Tarnopolsky ◽  
Cynthia Cupido
Keyword(s):  
Skeletal Muscle ◽  
Maximal Voluntary Contraction ◽  
Calcium Release ◽  
Low Frequency ◽  
Voluntary Contraction ◽  
Ergogenic Effect ◽  
Metabolic Effects ◽  
Stimulation Protocol ◽  
Custom Made ◽  
40 Hz

The mechanism of action underlying the ergogenic effect of caffeine is still unclear. Caffeine increases the force of muscular contraction during low-frequency stimulation by potentiating calcium release from the sarcoplasmic reticulum. Studies have also suggested an enhancement of lipid oxidation and glycogen sparing as potential mechanisms. Given that several studies have found an ergogenic effect of caffeine with no apparent metabolic effects, it is likely that a direct effect upon muscle is important. Twelve healthy male subjects were classified as habitual ( n = 6) or nonhabitual ( n = 6) caffeine consumers based on a 4-day diet record analysis, with a mean caffeine consumption of 771 and 14 mg/day for each group, respectively. Subjects were randomly allocated to receive caffeine (6 mg/kg) and placebo (citrate) in a double-blind, cross-over fashion ∼100 min before a 2-min tetanic stimulation of the common peroneal nerve in a custom-made dynamometer (2 trials each of 20 and 40 Hz). Tetanic torque was measured every 30 s during and at 1, 5, and 15 min after the stimulation protocol. Maximal voluntary contraction strength and peak twitch torque were measured before and after the stimulation protocol. Caffeine potentiated the force of contraction during the final minute of the 20-Hz stimulation ( P < 0.05) with no effect of habituation. There was no effect of caffeine on 40-Hz stimulation strength nor was there an effect on maximal voluntary contraction or peak twitch torque. These data support the hypothesis that some of the ergogenic effect of caffeine in endurance exercise performance occurs directly at the skeletal muscle level.

scholarly journals Application of subject-specific adaptive mechanical loading for bone healing in a mouse tail vertebral defect

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Angad Malhotra ◽  
Matthias Walle ◽  
Graeme R. Paul ◽  
Gisela A. Kuhn ◽  
Ralph Müller
Keyword(s):  
Mechanical Loading ◽  
Bone Defect ◽  
Bone Healing ◽  
Three Dimensional ◽  
Patient Specific ◽  
Dependent Manner ◽  
Micro Computed Tomography ◽  
Computed Tomography Images ◽  
Bone Defect Healing ◽  
Subject Specific

AbstractMethods to repair bone defects arising from trauma, resection, or disease, continue to be sought after. Cyclic mechanical loading is well established to influence bone (re)modelling activity, in which bone formation and resorption are correlated to micro-scale strain. Based on this, the application of mechanical stimulation across a bone defect could improve healing. However, if ignoring the mechanical integrity of defected bone, loading regimes have a high potential to either cause damage or be ineffective. This study explores real-time finite element (rtFE) methods that use three-dimensional structural analyses from micro-computed tomography images to estimate effective peak cyclic loads in a subject-specific and time-dependent manner. It demonstrates the concept in a cyclically loaded mouse caudal vertebral bone defect model. Using rtFE analysis combined with adaptive mechanical loading, mouse bone healing was significantly improved over non-loaded controls, with no incidence of vertebral fractures. Such rtFE-driven adaptive loading regimes demonstrated here could be relevant to clinical bone defect healing scenarios, where mechanical loading can become patient-specific and more efficacious. This is achieved by accounting for initial bone defect conditions and spatio-temporal healing, both being factors that are always unique to the patient.

scholarly journals Comparison of the different voxel sizes in the estimation of peri-implant fenestration defects using cone beam computed tomography: an ex vivo study

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Mehmet Hakan Kurt ◽  
Nilsun Bağış ◽  
Cengiz Evli ◽  
Cemal Atakan ◽  
Kaan Orhan
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Ex Vivo ◽  
Statistical Significance ◽  
Area Under The Curve ◽  
Titanium Implant ◽  
Bone Defects ◽  
Titanium Implants ◽  
Cone Beam ◽  
Voxel Size

Abstract Background To examine the influence of voxel sizes to detect of peri-implant fenestration defects on cone beam computed tomography (CBCT) images. Materials and methods This study performed with three sheep heads both maxilla and mandible and two types of dental implant type 1 zirconium implant (Zr40) (n = 6) and type 2 titanium implant (Ti22) (n = 10). A total of 14 peri-implant fenestrations (8 buccal surfaces, 6 palatal/lingual surface) were created while 18 surfaces (8 buccal, 10 palatal/lingual) were free of fenestrations. Three observers have evaluated the images of fenestration at each site. Images obtained with 0.75 mm3, 0.100 mm3, 0.150 mm3, 0.200 mm3, and 0.400 mm3 voxel sizes. For intra- and inter-observer agreements for each voxel size, Kappa coefficients were calculated. Results Intra- and inter-observer kappa values were the highest for 0.150 mm3, and the lowest in 0.75 mm3 and 0.400 mm3 voxel sizes for all types of implants. The highest area under the curve (AUC) values were found higher for the scan mode of 0.150 mm3, whereas lower AUC values were found for the voxel size for 0.400 mm3. Titanium implants had higher AUC values than zirconium with the statistical significance for all voxel sizes (p ≤ 0.05). Conclusion A voxel size of 0.150 mm3 can be used to detect peri-implant fenestration bone defects. CBCT is the most reliable diagnostic tool for peri-implant fenestration bone defects.

scholarly journals Low-frequency oscillations in cortical level to help diagnose task-specific dystonia

2021 ◽  
pp. 105444
Author(s):  
Chun-Chuan Chen ◽  
Antonella Macerollo ◽  
Hoon-Ming Heng ◽  
Ming-Kuei Lu ◽  
Chon-Haw Tsai ◽  
...  
Keyword(s):  
Low Frequency ◽  
Cortical Level ◽  
Low Frequency Oscillations

scholarly journals Analysis of the effects of spaceflight and local administration of thrombopoietin to a femoral defect injury on distal skeletal sites

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Ariane Zamarioli ◽  
Zachery R. Campbell ◽  
Kevin A. Maupin ◽  
Paul J. Childress ◽  
Joao P. B. Ximenez ◽  
...  
Keyword(s):  
Bone Loss ◽  
Mechanical Loading ◽  
Bone Healing ◽  
Space Flight ◽  
Bone Fracture ◽  
Local Administration ◽  
Systemic Effects ◽  
Human Presence ◽  
Femoral Defect ◽  
Healing Agent

AbstractWith increased human presence in space, bone loss and fractures will occur. Thrombopoietin (TPO) is a recently patented bone healing agent. Here, we investigated the systemic effects of TPO on mice subjected to spaceflight and sustaining a bone fracture. Forty, 9-week-old, male, C57BL/6 J were divided into 4 groups: (1) Saline+Earth; (2) TPO + Earth; (3) Saline+Flight; and (4) TPO + Flight (n = 10/group). Saline- and TPO-treated mice underwent a femoral defect surgery, and 20 mice were housed in space (“Flight”) and 20 mice on Earth for approximately 4 weeks. With the exception of the calvarium and incisor, positive changes were observed in TPO-treated, spaceflight bones, suggesting TPO may improve osteogenesis in the absence of mechanical loading. Thus, TPO, may serve as a new bone healing agent, and may also improve some skeletal properties of astronauts, which might be extrapolated for patients on Earth with restraint mobilization and/or are incapable of bearing weight on their bones.

scholarly journals Extra-gastric expression of the proton pump H+/K+-ATPase in the gills and kidney of the teleost Oreochromis niloticus

2020 ◽  
Vol 223 (16) ◽  
pp. jeb214890
Author(s):  
Ebtesam Ali Barnawi ◽  
Justine E. Doherty ◽  
Patrícia Gomes Ferreira ◽  
Jonathan M. Wilson
Keyword(s):  
Oreochromis Niloticus ◽  
Cellular Localization ◽  
Ex Vivo ◽  
Uptake Inhibition ◽  
Custom Made ◽  
Potassium Regulation ◽  
Immunohistochemical Techniques ◽  
Collecting Tubules ◽  
First Time

ABSTRACTPotassium regulation is essential for the proper functioning of excitable tissues in vertebrates. The H+/K+-ATPase (HKA), which is composed of the HKα1 (gene: atp4a) and HKβ (gene: atp4b) subunits, has an established role in potassium and acid–base regulation in mammals and is well known for its role in gastric acidification. However, the role of HKA in extra-gastric organs such as the gill and kidney is less clear, especially in fishes. In the present study in Nile tilapia, Oreochromis niloticus, uptake of the K+ surrogate flux marker rubidium (Rb+) was demonstrated in vivo; however, this uptake was not inhibited with omeprazole, a potent inhibitor of the gastric HKA. This contrasts with gill and kidney ex vivo preparations, where tissue Rb+ uptake was significantly inhibited by omeprazole and SCH28080, another gastric HKA inhibitor. The cellular localization of this pump in both the gill and kidney was demonstrated using immunohistochemical techniques with custom-made antibodies specific for Atp4a and Atp4b. Antibodies against the two subunits showed the same apical ionocyte distribution pattern in the gill and collecting tubules/ducts in the kidney. Atp4a antibody specificity was confirmed by western blotting. RT-PCT was used to confirm the expression of both subunits in the gill and kidney. Taken together, these results indicate for the first time K+ (Rb+) uptake in O. niloticus and that HKA is implicated, as shown through the ex vivo uptake inhibition by omeprazole and SCH28080, verifying a role for HKA in K+ absorption in the gill's ionocytes and collecting tubule/duct segments of the kidney.

Long-Term (9–12 Years) Outcomes of Titanium Implants With an Oxidized Surface: A Retrospective Investigation on 209 Implants

2015 ◽  
Vol 41 (4) ◽  
pp. 437-443 ◽  
Author(s):  
Marco Mozzati ◽  
Giorgia Gallesio ◽  
Massimo Del Fabbro
Keyword(s):  
Survival Rate ◽  
Bone Remodeling ◽  
Titanium Implants ◽  
Pocket Depth ◽  
Long Term Study ◽  
Bone Response ◽  
Single Tooth ◽  
Clinical Records

The aim of this paper is to retrospectively assess the long-term clinical and radiological results in a group of patients treated with Brånemark TiUnite implants supporting mostly single-tooth and partial restorations. The clinical records of 90 consecutive patients (mean age 55.9 years; range 21–82 years), treated with 209 Brånemark System MkIII or MkIV TiUnite implants (72 maxillary/137 mandibular; 26 anterior intercanine/183 posterior sites), were analyzed. Indication types were single tooth (n = 21 implants), partial (n = 180) and full arches (n = 8). A delayed loading protocol was applied in 128 implants, while 81 were immediately loaded. Cumulative survival rate and marginal bone remodeling were evaluated. Marginal bone level was evaluated by an independent radiologist from periapical radiographs taken at implant insertion and at long-term follow up. Plaque, probing pocket depth and peri-implant mucosa conditions were also assessed. The results showed the mean follow-up duration was 11.0 years (range 9.6–12.4 years): 181 implants (90.5%) reached at least 10 years follow-up, 100 implants 11 years, and 17 implants 12 years. Overall, 6 implants failed in 4 patients (5 during the first year and 1 after 2 years) resulting in a 97.1% survival rate after 12 years. Mean bone levels at implant insertion and at the last follow up were −0.90 ± 1.16 mm (mean ± SD; n = 169) and −1.49 ± 0.95 mm (n = 195), respectively. Mean marginal bone remodeling from implant insertion to the last follow-up was −0.60 ± 1.17 mm (n = 168). At the last available follow-up, mean pocket depth was 1.65 ± 0.84 mm. Peri-implant mucosa was normal for the majority (97%) of implants. In conclusion, this retrospective long-term study showed excellent survival rate of TiUnite implants as well as favorable marginal bone response and soft tissue conditions.

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