Dry coating is often used technology for preparation of solid pharmaceutical forms. It brings more benefits than the typically used wet coating technology. The powder, which is used as coating material, can be used immediately, has less environmental impact and enhances mechanical and aesthetic properties of final pharmaceutical form. Many technologies have been developed, being generally classified into the following types: compression coating, hot-melt coating, supercritical fluid coating, plasticizer dry coating, electrostatic dry coating, photocurable dry coating and modified plasticizer-electrostatic-heat dry coating. This review summarizes basic principles of dry coating technologies, their benefits and disadvantages and provides a comparison of them.
V orální implantologii se v současnosti ve velké šíři užívá kovový - technicky čistý titan nebo jeho slitiny. Tento materiál má optimální biologické vlastnosti, bohužel jeho technologické zpracování je obtížné a limitující pro výrobu některých forem dentálních implantátů. Příkladem obtížnosti jsou implantáty subperiostální. Cílem projektového výzkumu bylo nahrazení titanu, titanových slit, dobře zpracovatelnou chromkobaltovou slitinou povlakovanou keramickým materiálem ZrN nebo multivrst-vou Zr/ZrN a potvrzení její biokompatibility, dokonalé adhezivity a mechanické odolnosti. V práci prezentované výsledky prokazují vyhodnocení chemické odolnosti, která povlakováním podstatně snižuje uvolňování iontů chromkobaltové slitiny o 28-32 % v závislosti na drsnosti povrchu základní chromkobaltové slitiny. Výsledky se jeví pro implantace příznivě. Studie byla součástí grantového výzkumu IGA MZ ČR ND č. 7356-3 a následné činnosti Stomatologického výzkumného centra č. 1M0528.
In recent dental implantology, technically pure titanium or its alloys are broadly ušed as common metal materiál. The materiál possesses optimal biological characteristics. Unfortunately, its technological processing is difficult and limiting for production of some types of dental implants. Subperiostal implants might be pointed out in this respect. The objective of research project was to substitute titanium and titanium alloys for wellprocessed chromium-cobalt alloy coated with ceramic materiál ZrN or multilayered Zr/ZrN. Other objective was to prove its biocompatibility, full adhesivity and mechanical resistance. Results indicated high chemical resistan-ce, of the materiál that, thanks to coating, reduced ion relase from chromium —cobalt alloy by 28-32 % in relation to surface roughness. Such results are very promising for dental implantology. The study presented in this páper was supported by project No. 7356-3 provided by the IGA MZ ČR ND grant agency. The research was carried out within the frame of Stomatological Research Center numberlM0528 (SVC).
Acta orthopaedica Scandinavica ; Supplement Vol. 64. 255
58 s. : obr., tab. ; 25 cm
- MeSH
- Biocompatible Materials MeSH
- Hydroxyapatites MeSH
- Prostheses and Implants MeSH
- Dogs MeSH
- Foreign-Body Reaction MeSH
- Check Tag
- Dogs MeSH
- Conspectus
- Lékařské vědy. Lékařství
- NML Fields
- ortopedie
- transplantologie
The aim of this study was to develop a fast and reliable method for determination of tablet coating thickness. Tablets were coated with polymeric Pharmacoat® 606 in a laboratory coater. The coating thickness was measured by near-IR absorption of the coating material using calibration. The calibration and validation results afforded the following parameters: determination coefficient R2 > 0.97, the number of factors 6 and the standard error of crossvalidation 5.4 ?m at the coating thickness 25–125 ?m. The obtained results confirmed suitability of the method for evaluation of coating quality.
PURPOSE OF THE STUDY The hydroxyapatite coating of an implant surface provides osteoactive conditions that can support osteointegration of cement-less joint arthroplasties. However, the possibilities of hydroxyapatite degradation, resorption and delamination that may become responsible for failure of total hip arthroplasty (THA) have been reported. The aim of the study was to assess the properties of Arbond hydroxyapatite coating by comparing the long-term survival of implants identical in construction but different in surface coating. MATERIAL One group (HA) comprised 86 patients (100 THAs) with an average age of 45.14 years (range, 22.3 to 77.4 years) at the time of surgery who received a femoral stem (Walter) with a coating of Arbond sprayed over the proximal half. The other group (control) included 92 patients (100 THAs) with an average age of 49.7 years (range, 33 to 68.7) who had an identical femoral component without coating. In both groups the conical-shaped acetabular cup (Walter) and femoral head made of sintered ceramics were used. The patients in whom one or both components were replaced or extracted were not included in the final clinical evaluation (Harris Hip Score). For the statistical analysis of survival, a stable component still in place at the date of the revision procedure was regarded as surviving; a lose component at the same date was considered a failure. Finally, 71 hips of the HA group followed up for an average of 15.51 (range, 5.6 to 18.56) years and 39 control hips at an average follow-up of 14.19 (range, 6.24 to 18.48) years were clinically evaluated. The data of patients who died in the course of study (HA group, 11; control group, 14) were included in the clinical evaluation with the date of their last follow-up. METHODS For both groups, the Kaplan-Meier survival curves were constructed for overall survival and for the survival of acetabular and femoral components separately. Differences in survival curves were evaluated with the use of Gehan?s Wilcoxon test. Component survival was also calculated using 15-year life-table survivorship analysis. Differences in variables under study were assessed with the use of the two-tailed Student?s t-test. A p value of less than 0.05 was considered significant. RESULTS A total of 29 % hips were revised in the HA group, 27 % for aseptic loosening of the acetabular cup, in 2 % both components were removed because of deep infection. In the control group revision procedures were performed in 61 % of the hips. Except for one case of deep infection (1 %), the reason was cup loosening in 30 %, stem loosening in 12 % and both components loosening in 18 % of the hips. The HA group showed a significantly longer survival of both total hip prostheses and individual components. The final HHS was significantly better than the initial score in both groups. There was no difference in the degree of improvement between the two groups. The radiographic data showed full osteointegration of stems in the HA group. The control group, on the other hand, had 87 % of the stems with translucent lines in zone I and zone VII according to Gruen?s classification. DISCUSSION The significantly longer survival of hips in the HA group gives support to the use of hydroxyapatite coating in total hip arthroplasty. The poorer results in grit-blasted implants, as compared with the literature data, can be explained by alow degree of roughness of the Walter implant surfaces. CONCLUSIONS The combined Arbond hydroxyapatite coating improves conditions for implant osteointegration in the bone.
- MeSH
- Coated Materials, Biocompatible MeSH
- Adult MeSH
- Durapatite MeSH
- Kaplan-Meier Estimate MeSH
- Hip Prosthesis MeSH
- Middle Aged MeSH
- Humans MeSH
- Arthroplasty, Replacement, Hip MeSH
- Osseointegration MeSH
- Prosthesis Design MeSH
- Reoperation MeSH
- Prosthesis Failure MeSH
- Aged MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Aged MeSH
INTRODUCTION: The main purpose of this study is to evaluate the efficacy of the plasma sprayed, combined porous titanium alloy/HA coating in promoting bony ingrowth and mechanical stabilization of total hip implants. The performance of the titanium alloy/HA type coated hip prostheses and the one of the same shape but without any coating, is compared in this paper. MATERIAL AND METHODS: The implants were manufactured from titanium alloy VT-6 (ASTM F-136). The hip stems utilized in the control group were identical to those subsequently coated. The coating consists of a plasma deposited first layer of porous titanium alloy (TiAl(6)V(4)), similar in composition to the forged substrate and a plasma deposited second layer of over-sprayed hydroxyapatite, Ca(10)(PO(4))6(OH)2. Coating is located in the critical area of the hip stems, where high fixation interface strength is desired, i.e. in the proximal area of the stem where the highest stresses occur. The porous titanium alloy/hydroxyapatite (HA) coated femoral stems were implanted in 50 patients. The results were compared with a control group of 50 patients with the same type of endoprosthesis, but without the porous titanium alloy/HA coating. Both groups of patients were operated on and evaluated by the same orthopedic surgeons with a mean follow up of 11.4 years in the HA group and 10.6 years in the control group. RESULTS: HHS in the control group was preoperatively 35.5 points (range 26-49) and 85.1 points (range 54-100) in the time of the last control. HHS in the HA group was preoperatively 34.1 points (range 27-56) and 94.4 points (range 89-100) in the time of the last control. In 28 cases (56%) of the control group a range of translucencies were obvious. These translucent lines, however, did not appear with any of the patients in the coated implant group except one infection stem migration. CONCLUSION: Experience with the HA-type coated hip implants demonstrates substantially higher degree and quality of osteointegration in the porous titanium alloy/HA type implants.
- MeSH
- Coated Materials, Biocompatible MeSH
- Adult MeSH
- Durapatite MeSH
- Hip Prosthesis MeSH
- Middle Aged MeSH
- Humans MeSH
- Osseointegration MeSH
- Prosthesis Design MeSH
- Aged MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Randomized Controlled Trial MeSH
