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Evaluation of Titanium-nitride Coated Crown: Surface Hardness, Corrosion Resistance and Color Sustainability
Abstract
The purpose of this study was to compare surface hardness between titanium-nitride coated crowns (TiNCs) and stainless steel crowns (SSCs), and to evaluate the corrosion resistance and color sustainability of TiNCs. Ten TiNCs and 10 SSCs were used for the hardness test. Measurement was performed 30 times for each type of crowns, and the mean values were compared. Metallic raw material plates (before being processed into crowns) of TiNCs and SSCs were prepared for the corrosion resistance test. The total amounts of metal ion releases in the test solution were detected by inductively coupled plasma-optical emission spectrometry. Five TiNCs were subjected to the color sustainability test by applying repetitive brushing forces. The mean hardness values of TiNC group and SSC group were 395.53 ± 105.90 Hv and 278.70 ± 31.45 Hv respectively. Hardness of TiNCs were significantly higher than that of SSCs. The total amounts of metal ion releases from the materials of TiNCs and SSCs satisfied the criterion in International Organization for Standardization 22674. The results mean that TiNCs and SSCs were not harmful in an acidic environment. The golden coating was stable against the repetitive physical stimulations for a given period time.
... In the recent past Titanium-nitride coated (TiN) SSC has been introduced and available for use. TiN-coating makes the crown appear golden and yellow and the coating may play a role in strengthening hardness of the surface [7]. The golden colour of the crown tend to attract children's attention and seemed to be more likeable. ...
... Recently, a new full coverage crown has been introduced by Shinhung Co. Ltd. Titanium coated golden stainless-steel crown, they are stainless steel crown having natural golden luster through titanium coating which provides high quality esthetic finish [7]. The golden colour of the crown tends to more appealing and attractive to the children as well as parents instead of silver of Conventional SSC as the silver colour is less attractive than golden colour. ...
Background
All soft and solid surface structures in the oral cavity are covered by the acquired pellicle followed by bacterial colonization. This applies for natural structures as well as for restorative or prosthetic materials; the adherent bacterial biofilm is associated among others with the development of caries, periodontal diseases, peri-implantitis, or denture-associated stomatitis. Accordingly, there is a considerable demand for novel materials and coatings that limit and modulate bacterial attachment and/or propagation of microorganisms.
Objectives and findings
The present paper depicts the current knowledge on the impact of different physicochemical surface characteristics on bioadsorption in the oral cavity. Furthermore, it was carved out which strategies were developed in dental research and general surface science to inhibit bacterial colonization and to delay biofilm formation by low-fouling or “easy-to-clean” surfaces. These include the modulation of physicochemical properties such as periodic topographies, roughness, surface free energy, or hardness. In recent years, a large emphasis was laid on micro- and nanostructured surfaces and on liquid repellent superhydrophic as well as superhydrophilic interfaces. Materials incorporating mobile or bound nanoparticles promoting bacteriostatic or bacteriotoxic properties were also used. Recently, chemically textured interfaces gained increasing interest and could represent promising solutions for innovative antibioadhesion interfaces. Due to the unique conditions in the oral cavity, mainly in vivo or in situ studies were considered in the review.
Conclusion
Despite many promising approaches for modulation of biofilm formation in the oral cavity, the ubiquitous phenomenon of bioadsorption and adhesion pellicle formation in the challenging oral milieu masks surface properties and therewith hampers low-fouling strategies.
Clinical relevance
Improved dental materials and surface coatings with easy-to-clean properties have the potential to improve oral health, but extensive and systematic research is required in this field to develop biocompatible and effective substances.
Aim
To evaluate the occlusal bite force (OBF) changes 6 months after placement of preformed metal crowns PMCs on primary molars in children.
Method
Twenty-two subjects (aged 5.08 ± 0.92 years) participated and completed OBF records. Each patient received eight PMCs on their primary molars. OBF was recorded using a battery-operated portable type of OBF gauge at different time intervals: before placement, 1 week-, 1 month-, 2 months-, 3 months-, and 6 months after PMCs placement (T0–T5). A second group consisted of 22 caries-free children matched for age and gender were selected as a control sample and received no dental treatment. OBF was recorded in these subjects at T0 and T5 (6 months after).
Results
OBF was reduced the first week after placement of PMCs. However, the OBF was restored and reached its original value at T4. At the 6-month recall visit (T5), maximum occlusal bite force (MOBF) was 148% and 136% of pre-treatment value on right and left sides, respectively. The mean MOBF difference between T5 and T0 was statistically significant (70.83N and 54.67N on the right and left sides respectively, p < 0.000).
Conclusion
OBF decreased 1 week after placement of PMC restoration and started to increase after 1 month reaching 136–140% of its original value after 6 months.
Surfaces of medical implants can be enhanced with the favorable properties of titanium-nitride (TiN). In a review of English medical literature, the effects of TiN-coating on orthopaedic implant material in preclinical studies were identified and the influence of these effects on the clinical outcome of TiN-coated orthopaedic implants was explored. The TiN-coating has a positive effect on the biocompatibility and tribological properties of implant surfaces; however, there are several reports of third body wear due to delamination, increased ultrahigh molecular weight polyethylene wear, and cohesive failure of the TiN-coating. This might be due to the coating process. The TiN-coating process should be optimized and standardized for titanium alloy articulating surfaces. The clinical benefit of TiN-coating of CoCrMo knee implant surfaces should be further investigated.
The purpose of this retrospective study was to compare the success rates of formocresol pulpotomy in primary molars restored with stainless steel crowns (SSC) to those restored with amalgam (AM).
Radiographs of pulpotomized primary molars restored with SSC or AM in the principal author's pediatric dentist practice were evaluated and defined as a "failure" when one or more of the following signs were present: internal (IR) or external (ER) root resorption and periapical (PR) or inter-radicular (IRR) radiolucency. Pulp canal obliteration was not regarded as failure. Three hundred and forty-one molars were available for follow-up evaluations ranging from 6 to 103 months.
Forty-seven (14%) teeth were defined as "failure," with a rate of 13% (36/287) for teeth restored with SSC and 20% (11/54) for AM. This difference was not statistically significant (P>0.1). Failure rates of 2 surfaces AM was 23% (7/30), much higher than that of one surface AM (10%, 2/20). Most of the failed teeth presented more than one pathologic finding, with IR being the most frequently observed (36%), followed by ER (31%), IRR (22%) and PR (11%). Pulp canal obliteration was detected in 80% of the teeth, with similar rates in both groups. Failures were observed initially after a mean follow-up of 27 and 29 months in teeth restored with AM and SSC, respectively.
Pulpotomized primary molars can be successfully restored with one surface amalgam if their natural exfoliation is expected within not more than two years.
This paper describesperforation/fracture tests performed perforation/fracture tests performed in large sandstone blocks in a triaxialstress cell to determine perforatinggeometry and perforating-fractureprocedures for optimal fracture procedures for optimal fracture initiation. Four-shot, 1800 phasedperforating guns, steel casing, and perforating guns, steel casing, and oilfield cement were used. In oneseries of experiments, the casing wascemented and cured while undertriaxial stress. Most tests were madewith pore pressure, and vertical andhorizontal wells were simulated. Ingeneral, the tests showed that(1) fractures initiate either at the baseof perforations or at the intersectionof the plane normal to the minimumhorizontal stress that passes throughthe axis of the wellbore and thewellbore surface and (2) fracture initiationdepended on perforation orientationwith respect to the plane normal tothe minimum horizontal stress andthe properties and injection rate ofthe fracture fluid. All fracturesreoriented into the plane normal to theminimum horizontal stress within onewellbore diameter; although multiplefractures were initiated, only primarysingle fractures propagated beyondone wellbore diameter.
Introduction
Laboratory simulation of fracturing throughcased and perforated wellbores generally hasbeen performed with one or more of thefollowing limiting conditions:scaled tests(rate effects ignored),artificial rock(cement, plaster of Paris, or hydrostone),isolation of the perforations from thewellbore (no pressurization between thescaled casing and the rock),noporoelastic effects (impermeable rock or poroelastic effects (impermeable rock or high-viscosity fracturing fluid),artificially scaled perforations(no perforation damage), andno pore pressure (impermeable ordry rock). Extrapolation of laboratory results todownhole situations must proceed withcaution whenever any of these conditions arepart of the laboratory experiment.
For part of the laboratory experiment. For example, Condition 3 is unrealistic downholeand Condition 5 may apply only in specialsituations of high underbalance perforating. Conditions 4 and 6, however, may simulatea well with extensive wellbore andperforation damage. To the best of our knowledge, perforation damage. To the best of our knowledge, Warpinski's mineback experiments, inwhich annulus fractures were observed, were the only experiments conducted in theabsence of these conditions. The experiments discussed in this paperwere planned to evaluate the effect ofperformations on fracture initiation. Because of performations on fracture initiation. Because of the limiting-condition issues discussedabove, fill-scale experiments wereconducted in sandstone rock in a large triaxial stressframe that simulated downhole conditions.
Test Fixture
The fracture-initiation experiments wereperformed in 27×27×32-in. sandstone performed in 27×27×32-in. sandstone blocks in Terra Tek's 8, psitriaxial stress frame. The circular frame andits top and bottom platens surround the rockand provide reactions for three independentpairs of flat jacks. Flat-jack efficiency was pairs of flat jacks. Flat-jack efficiency was measured at 91 %; all applied stress datause this correction. Access to the centralwellbore is provided through the top loadingplate. Pore pressure was applied by placing plate. Pore pressure was applied by placing the rock in a stainless-steel can with rubberseals on the top and bottom faces. The canallowed the placement of about 0.25 in. ofbauxite beads around the four faces. Theborehole was cored to 4% in., and 3-in. OD × 2 1/2 -in. ID) steel tubing was cementedin place. Through-tubing, 1 11/16-in. orin., 4-shot/ft (SPF), 180 degs phased guns withthree or four shots were used. Table 1 givesthe rock properties.
Experimental Procedure
Three sets of tests were conducted (Table2). Experimental techniques were enhancedwith each additional set. Rock saturation andpore pressure were added to Set 2. An in-situ pore pressure were added to Set 2. An in-situ pore pressure gauge, a large 2.38-gal pore pressure gauge, a large 2.38-gal intensifier, and casing cemented and cured understress were added to Set 3. The general test procedure was as follows.1. Vacuum saturate the rocks with 3%brine, flowing brine from the uncasedwellbore to the rock sides (Sets 2 and 3 only).2. Cement casing into rock and allow tocure (Sets 1 and 2 only).3. Place rock into test frame. For Set 3, casing was cemented in place before theframe was closed and cured while understress.4. Place perforating gun in wellbore.5. Close frame, apply desired flat-jackand pore pressures; the wellbore is ventedto atmosphere.6. Fire gun. For Set 3, the casing cementcured for a minimum of 24 hours before thegun was fired.7. Flow brine at 2,000 psi from the beadpack through perforations; measure flow pack through perforations; measure flow rate8. Perform various prefractureprocedures depending on test set. procedures depending on test set. 9. Fracture rock with red dye used infracture fluids.10. Remove, cut open, and examine rock.
Experimental Results
Set 1, Torrey Buff Sandstone. Equipmentfailure prevented on of the specimensin this set. After perforation, the wellborewas flushed with brine, and on Tests 2 and4, brine was injected at low pressure throughthe perforations to saturate the rock locallynear the wellbore.
JPT
P. 608
Six samples of cold work tool steel were used as substrates for physical and chemical vapour deposition coatings. Three of them were made of a powder metallurgy steel called Vanadis-4, the other three were Carmo steel. Both are commercial Swedish tool steels. TiN and CrN coatings were deposited onto both steels using physical vapour deposition. The TiC coating was deposited onto Vanadis-4 and a TiC/CrC composite coating was deposited onto Carmo using chemical vapour deposition. The area law of mixture model was used to estimate the hardnesses of the investigated coatings. These values were reasonably close to the experimental coating hardnesses measured at 10 or 25 g load which were still affected by substrate deformation. The increase in coating thickness due to the rougher substrate surface caused an increase in coating hardness. The shape and behaviour of lateral cracking in the indentation impressions for different coatings was studied.
Infection of an orthopedic prosthesis is undesirable and causes a decrease in the success rate of an implant. Reducing the adhesion of a broad range of bacteria could be an attractive means to decrease infection and allow for subsequent appropriate tissue integration with the biomaterial surface. In this in vitro study, nanometer sized topographical features of titanium (Ti) surfaces, which have been previously shown to enhance select protein adsorption and subsequent osteoblast (bone-forming cell) functions, were investigated as a means to also reduce bacteria adhesion. This study examined the adhesion of Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa on conventional Ti, nanorough Ti produced by electron beam evaporation, and nanotubular and nanotextured Ti produced by two different anodization processes. This study found that compared to conventional (nano-smooth) Ti, the nanorough Ti surfaces produced by electron beam evaporation decreased the adherence of all of the aforementioned bacteria the most. The conventional and nanorough Ti surfaces were found to have crystalline TiO(2) while the nanotubular and nanotextured Ti surfaces were found to be amorphous. The surface chemistries were similar for the conventional and nanorough Ti while the anodized Ti surfaces contained fluorine. Therefore, the results of this study in vitro study demonstrated that certain nanometer sized Ti topographies may be useful for reducing bacteria adhesion while promoting bone tissue formation and, thus, should be further studied for improving the efficacy of Ti-based orthopedic implants.
This article focuses on the surface engineering of ventricular assist devices (VADs) for the treatment of heart failure patients, which involves the modification of surfaces contacting blood in order to improve the blood compatibility (hemocompatibility) of the VADs. Following an introduction to the categorization and the complications of VADs, this article pays attention on the hemocompatibility, applications and limitations of six types of surface coatings for VADs: titanium nitride coatings, diamond-like carbon coatings, 2-methacryloyloxyethyl phosphorylcholine polymer coatings, heparin coatings, textured surfaces and endothelial cell linings. In particular, diamond-like coatings and heparin coatings are the most commonly used for VADs owing to their excellent hemocompatibility, durability and technical maturity. For high performance and a long lifetime of VADs, surface modification with coatings to ensure hemocompatibility is as important as the mechanical design of the device.
Titanium and its alloys are increasingly important in dentistry. Thin titanium nitride (TiN) coatings improve properties of metallic material for industrial purposes. Recently TiN coatings have been advocated in dentistry. In a survey of the literature, aspects of biological, mechanical and corrosive behaviour are assessed. Moreover, specific problems for clinical application are indicated. It is concluded that as long as the integrity of the TiN coating is not guaranteed under critical conditions, one should be cautious with its clinical application, and in no situation can it be used to improve deficient dental alloys.
The most durable and reliable method of retaining a primary molar in the mouth after a pulpotomy procedure is complete-coverage restoration with a preformed stainless steel crown. This paper describes a method for performing pulpotomy and stainless steel crown restoration of a primary molar. Neither formocresol, glutaraldehyde, nor calcium hydroxide is used during the pulpotomy phase of the treatment.
The sensing and pacing performance of pacemaker electrodes is characterized by the electrochemical properties of the electrodes/tissue layer; the usually smooth metallic electrode surface results in a high pass filter characteristic. Consequently, the detected intracardiac signals, which control the implantable systems, are not optimally matched to the spectral contents of the depolarisation signal. To avoid interference caused by noise (EMI, muscle potentials, etc.) a shift of the frequency of the band pass towards the lower frequency spectrum is required. As previously reported, the electrochemical properties of sintered and surface-treated electrodes prove the predicted improvement of sensing performance if titanium-nitride coated electrodes are used. Our results demonstrate their superiority above all the other electrodes presently known. The advantages can be referred to the micro-crystalline surface structure achieved by sputter-deposited electrode coatings and the kinetics of the ionic exchange. Furthermore, the acute thresholds achieved with the TiN-systems were significantly better than those of the smooth metallic surface. These results were also confirmed for chronic implants and are attributable to the known biocompatibility of titanium and its alloys.
The requirements for successful joint arthroplasty are particularly exacting; a balanced combination of mechanical properties together with good biocompatibility are essential. Co-Cr based alloys have been used for many years on account of their relative inertness, good load bearing properties and excellent wear resistance. There is, however, concern that a slow accumulation of metal ions such as cobalt and chromium can lead to adverse clinical reactions; modern cementless fixation techniques may exacerbate this problem. In an attempt to reduce the release of potentially harmful metal ions from Co-Cr-Mo based surgical implants, a thin coating of TiN has been applied via Physical Vapour Deposition (PVD). In vitro corrosion performance has been investigated using electrochemical techniques, and also by atomic absorption analysis. The release of cobalt and chromium ions is shown to be reduced by the presence of the TiN coating, and these results are discussed in terms of the electrochemistry and microstructure of the coating and substrate.
Many choices are available to the practitioner of restorative dentistry for children. With the introduction of several new classes of restorative materials in recent years, some confusion has been created about what these materials are, making it difficult to identify their appropriate clinical use. This paper reviews glass-ionomer materials, resin-modified (reinforced) glass ionomers, compomers, and composite resins for the practitioner. Definitions of these materials, a general description of their contents, and usage-selection criteria are provided. Although more choices for tooth restoration can make the selection of the right material more difficult, a better understanding of the components and the strengths and weaknesses of each category of materials offers the opportunity to select the right material for the right situation.
The aim of this study was to investigate the relation between clenching strength and occlusal force distribution in primary dentition. Twenty healthy children with normal occlusions: 11 boys and 9 girls, ages 3.2-5.8 years (avg. 4.5 years) were selected. Setting the bilateral masseter muscular activity at maximum clenching in full intercuspation as 100%, the occluding forces at 20, 40, 60, 80 and 100% clenching were recorded with pressure-sensitive sheets (Dental Prescale 50H, type R, Fuji Photo Film Co.), and the force of each primary tooth was analysed by computer (Occluzer FPD703). Occlusal force distribution was expressed as a percentage of the total occlusal force of each tooth and was compared between each clenching. There were no significant differences between various clenching strengths in the occlusal force distribution in primary dentition [one-way repeated-measures analysis of variance (ANOVA)]. Thus, the results of the present study suggest that the distribution of occluding forces on a primary dental arch had its own pattern and that the clenching strength had no effect on that pattern. These patterns may be useful in determining occlusal function in children.
To prospectively report on the survival of resin-modified glass ionomer cement (RMGIC), photac-fil and pre-formed stainless steel crown (SSC) restorations in primary molar teeth placed over a seven-year period in a specialist paediatric dental practice under private contract of remuneration.
All primary molar restorations placed by a specialist paediatric dentist over a seven-year period were reviewed and the outcome results recorded. Data were recorded at review visits until June 30, 2003. Data recorded included Class I restorations, Class II restorations and SSC. The Class II cavities were either mesial or distal, with or without buccal/palatal extensions. If both proximal surfaces were decayed or if after cavity preparation the resultant outline form was significantly larger than the minimal classical form, RMGIC was not used; an SSC was placed instead. Stainless steel crown preparation followed conventional guidelines. The crowns were cemented with reinforced zinc oxide and eugenol (Kalzinol). The status was recorded as satisfactory restoration, tooth exfoliated, tooth extracted for orthodontic reasons with the date of extraction, or needing replacement. If replaced then the reason for replacement was also recorded.
A total of 544 Class I RMGICs, 962 Class II RMGICs, and 1,010 SSCs were placed. At the last review of each restoration, 98.3% of Class I, 97.3% of Class II RMGICs and 97.0% of SSCs were either satisfactory or withdrawn intact.
Under the conditions of private specialist practice-based study SSCs continued to prove very successful for the restoration of larger cavities and for pulp-treated primary molar teeth. For the smaller cavities RMGIC were also very successful.
New results on the relationship between hardness and fracturetoughness of WC-Co hard metal
- Dgf O'quigley
- S Luyckx
- M N James
O'Quigley DGF, Luyckx S, James MN : New results on the
relationship between hardness and fracturetoughness of
WC-Co hard metal. Mater Sci Eng, 209:228-230, 1996.