Browsing by Author "Rajesh, P"

Now showing 1 - 6 of 6
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    Combined Treatment Effects Using Bioactive-Coated Implants and Ceramic Granulate in a Rabbit Femoral Condyle Model
    (CLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, 2016) Preethanath, RS; Rajesh, P; Varma, H; Anil, S; Jansen, JA; van den Beucken, JJJP
    Background: Resolution of peri-implant defects resulting from implant placement in the freshly extracted site demands for a bone graft substitute that stimulates bone regeneration and hence facilitates implant integration. In view of this, the addition of silica to hydroxyapatite (HASi) could enhance the bioactive behavior of ceramic materials and implant surfaces coated with bioactive ceramics might benefit the interaction between bone and implant. Purpose: To evaluate the bone response to implants coated with hydroxyapatite-silica (HASi) or hydroxyapatite (HA) and either or not combined with HASi and HA ceramic bone substitute particles, respectively, on bone-to-implant contact (BIC) and bone formation using a rabbit femoral condyle implant model with a gap design. Material and Methods: A total of 32 custom-made, titanium implants (Ti: diameter 5 mm, length 8 mm) with two-sided gaps were fabricated and coated with either HASi or HA using pulsed laser deposition (PLD). The implants were installed bilaterally in the femoral condyles of 16 New Zealand white rabbits. According to a randomization protocol, one gap of HASi-coated and HA-coated implants was filled with HASi particles and HA particles, respectively, and the other gap was left empty. After an implantation period of 8 weeks, the retrieved specimens were analyzed via histology and histomorphometry (i.e., bone to implant contact [BIC] and bone volume [BV]). Results: The BIC and BV around the implants were analysed for HASi-and HA-coated implants with and without the use of HASi and HA bone substitute material. Comparison of HASi-and HA-coated implants showed similar BIC for HASi( 55.7 + 11.0) and HA-coated implants (50.3 + 19.7). When coated implants were combined with bone substitute materials, HASi-coated and particle-filled implants showed higher BIC (64.3 +/- 6.8%) compared with HA-coated and HA-filled implants (54.5 +/- 10.9%). Similarly, the BV within the region of interest showed significantly higher values for the HASi-coated and HASi-filled implants (21.1 +/- 1.7%) compared with HA-coated and HA-filled implants (12.8 +/- 4.9%). Conclusions and Clinical Implications: Within the limitations of this study, it can be concluded that silicon substitution in HA favors bone regeneration compared with HA, especially when used as bone substitute material. Further studies using different healing periods will elucidate the resorption pattern of HASi granules in comparison with HA.
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    Combined Treatment Effects Using Bioactive-Coated Implants and Ceramic Granulate in a Rabbit Femoral Condyle Model.
    (Clinical Implant Dentistry and Related Research, 2015-06) Reghunathan, SP; Rajesh, P; Varma, H; Sukumaran, AS; Jansen, JA; Beucken, JJP
    Background: Resolution of peri-implant defects resulting from implant placement in the freshly extracted site demands for a bone graft substitute that stimulates bone regeneration and hence facilitates implant integration. In view of this, the addition of silica to hydroxyapatite (HASi) could enhance the bioactive behavior of ceramic materials and implant surfaces coated with bioactive ceramics might benefit the interaction between bone and implant. Purpose: To evaluate the bone response to implants coated with hydroxyapatite-silica (HASi) or hydroxyapatite (HA) and either or not combined with HASi and HA ceramic bone substitute particles, respectively, on bone-to-implant contact (BIC) and bone formation using a rabbit femoral condyle implant model with a gap design. Material and Methods: A total of 32 custom-made, titanium implants (Ti: diameter 5 mm, length 8 mm) with two-sided gaps were fabricated and coated with either HASi or HA using pulsed laser deposition (PLD). The implants were installed bilaterally in the femoral condyles of 16 New Zealand white rabbits. According to a randomization protocol, one gap of HASi-coated and HA-coated implants was filled with HASi particles and HA particles, respectively, and the other gap was left empty. After an implantation period of 8 weeks, the retrieved specimens were analyzed via histology and histomorphometry (i.e., bone to implant contact [BIC] and bone volume [BV]). Results: The BIC and BV around the implants were analysed for HASi- and HA-coated implants with and without the use of HASi and HA bone substitute material. Comparison of HASi- and HA-coated implants showed similar BIC for HASi- (55.7 + 11.0) and HA-coated implants (50.3 + 19.7).When coated implants were combined with bone substitute materials, HASi-coated and particle-filled implants showed higher BIC (64.3 1 6.8%) compared with HA-coated and HA-filled implants (54.5 1 10.9%). Similarly, the BV within the region of interest showed significantly higher values for the HASicoated and HASi-filled implants (21.1 1 1.7%) compared with HA-coated and HA-filled implants (12.8 1 4.9%). Conclusions and Clinical Implications: Within the limitations of this study, it can be concluded that silicon substitution in HA favors bone regeneration compared with HA, especially when used as bone substitute material. Further studies using different healing periods will elucidate the resorption pattern of HASi granules in comparison with HA.
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    Enhancement of wettability and antibiotic loading/release of hydroxyapatite thin film modified by 100 MeV Ag7+ ion irradiation
    (MATERIALS CHEMISTRY AND PHYSICS, 2012) Elayaraja, K; Rajesh, P; Joshy, MIA; Chandra, VS; Suganthi, RV; Kennedy, J; Kulriya, PK; Sulania, I; Asokan, K; Kanjilal, D; Avasthi, DK; Varma, HK; Kalkura, SN
    The effect of swift heavy 100 MeV Ag7+ ions irradiation was studied on hydroxyapatite (HAp) thin film prepared by pulsed laser deposition technique (PLD). The GIXRD analysis confirmed the absence of any phase in the HAp phase due to irradiation. In addition, there was a considerable decrease in crystallinity and crystallite size on irradiation. There was no significant variation in the stoichiometry of the irradiated films. Irradiation seemed to decrease the optical band gap energy of HAp thin films. The surface roughness, wettability and bioactivity were improved on irradiation of the samples. Amount of amoxicillin loading/release increased (10%) in ion beam irradiated (1 x 10(12) ions cm(-2)) sample. Irradiated sample showed fast rate of amoxicillin (AMX) release than the pristine. Bactericidal effect was found to increase on irradiation. Surface modified and antibiotics incorporated HAP coated titanium implants may be used to prevent post-surgical infections and to promote bone-bonding of orthopedic devices. (C) 2012 Elsevier B.V. All rights reserved.
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    Finger tapping activates spikes in benign epilepsy with centro-temporal spikes
    (NEUROLOGY INDIA, 2002) Rajesh, P; Vinayan, KP; Thomas, SV
    A case of benign epilepsy with centro-temporal spikes (BECT) is reported, in whom tapping of fingures activated typical spikes.
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    Formation of hydroxyapatite coating on titanium at 200A degrees C through pulsed laser deposition followed by hydrothermal treatment
    (BULLETIN OF MATERIALS SCIENCE, 2011) Komath, M; Rajesh, P; Muraleedharan, CV; Varma, HK; Reshmi, R; Jayaraj, MK
    Pulsed laser deposition (PLD) has emerged as an acceptable technique to coat hydroxyapatite on titanium-based permanent implants for the use in orthopedics and dentistry. It requires substrate temperature higher than 400A degrees C to form coatings of good adhesion and crystallinity. As this range of temperatures is likely to affect the bulk mechanical properties of the implant, lowering the substrate temperature during the coating process is crucial for the long-term performance of the implant. In the present study, hydroxyapatite target was ablated using a pulsed Nd:YAG laser (355 nm) onto commercially pure titanium substrates kept at 200A degrees C. The coating thus obtained has been subjected to hydrothermal treatment at 200A degrees C in an alkaline medium. The coatings were analysed using microscratch test, optical profilometry, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and infrared spectroscopy (FTIR). XRD, EDS and FTIR showed that the as-deposited coating contained amorphous calcium phosphate and the hydrothermal treatment converted it into crystalline hydroxyapatite. The micro-morphology was granular, with an average size of 1 micron. In the micro-scratch test, a remarkable increase in adhesion with the substrate was seen as a result of the treatment. The plasma plume during the deposition has been analysed using optical emission spectroscopy, which revealed atomic and ionic species of calcium, phosphorous and oxygen. The outcomes demonstrate the possibility of obtaining adherent and crystalline hydroxyapatite on titanium substrate at 200A degrees C through pulsed laser deposition and subsequent hydrothermal treatment.
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    Pulsed laser deposition of hydroxyapatite on nanostructured titanium towards drug eluting implants
    (Materials Science and Engineering: C. 2013, 2013-04) Rajesh, P; Mohan, N; Yokogawa, Y; Varma, HK