Metal Inlay Research Articles

Numerical and Non-Destructive Analysis of an Aluminum-CFRP Hybrid 3D Structure

Advanced materials are widely used in many industries. They play an important role especially in the aeronautic and automotive sectors where weight reduction is required in order to reduce fuel consumption. Composite materials have a high strength to weight ratio and are applied in airplane construction. Nevertheless, sometimes it is not viable to replace all metal parts by composite ones due to the cost factor. In this sense, hybrid structures are highly welcome. In order to ensure the safety of these hybrid components during their entire life cycle, non-destructive testing evaluation (NDT&E) methods are used and sometimes they are the only option. In this study, we use infrared thermography (IRT) to inspect an aluminum-composite hybrid structure with a 3D shape. The sample has a composite part with a small metal inlay (EN AW-6082) overmolded with a thermoplastic layer. The inlay is bended to reach the desired 3D geometry. This sample was design to be used for the connection between an A- or B-pillar and a car roof made of carbon fiber reinforced polymer (CFRP). A dual-band infrared camera is used in order to capture images in two different spectral ranges. In addition, two data processing techniques for infrared images are applied to enhance the images: principal component thermography (PCT) and partial least squares thermography (PLST). Then, a signal-to-noise ratio analysis is performed with three randomly chosen previous known defects to assess the quality of the images and detected defects. Results showed that principal component thermography has a slight advantage over partial least squares thermography in our specific experiments. Specifically, for the long-wave infrared band, PCT presented, among the defects analyzed, PCT presented a mean value 12.5% higher while the standard deviation was almost three times lower than PLST. In parallel to the non-detructive analysis, a numerical finite element model was formulated in ANSYS® to analyze the total deformations to which the metal-composite-hybrid structure is subjected during a possible use. Results obtained with the numerical model indicate that the interface region between composite and metal parts is where the highest degree of deformation occur, which indicates possible regions where defects and failures may occur in real use cases.

Extraordinary Burial of Trikolsky Burial Ground in the Lower Reaches of the Belaya River

The article introduces into scientific discourse the materials of the burial 15 of the Trikolsky burial ground studied in 1978 by V.A. Ivanov. This burial featured finds unique for the entire Pyany Bor culture – a glass bowl and a cassolette. The burial also contained beads made of single-color and multi-colored glass and glass with a metal inlay, pendants made of adult moose incisors, bronze plaques, openwork overlays, temple pendants, etc. The authors concluded that the unique items came to the Pyany Bor population as a result of contacts with Sarmatian nomads in the 1st century AD. In addition, the study presents data on the manufacturing material of certain items obtained using natural scientific methods. It was determined that the cassolette was made of a sedimentary rock – argillite. Metal items, except a leaf-shaped pendant made of precious metal, are made of tin bronze. A “gum” sample discovered next to a glass bowl contains matter of vegetable origin. Its components are betulinic and tricyclic acids contained in birch bark and conifer resin (oleoresin), respectively.

The Influence of Cement Layer Thickness on the Stress State of Metal Inlay Restorations-Photoelastic Analysis.

The successful restoration of teeth requires a good connection between the inlay and natural tissue. A strong bond may improve retention and reinforce tooth structure. The purpose of this study was to evaluate the influence of cement layer thickness on contraction stress generated during photopolymerization, and to determine the changes in stress state of the cement occurring during aging in water (over 84 days). Two cements were used: resin composite cement (NX3) and self-adhesive resin cement (Maxcem Elite Chroma). A cylindrical sample made of CuZn alloy was used to imitate the inlay. The stress state was measured by photoelastic analysis. The contraction stress of the inlay restoration was calculated for cement layer thicknesses of 25 µm, 100 µm, 200 µm, and 400 µm. For both tested materials, the lowest contraction stress was observed for the thinnest layer (25 µm), and this increased with thickness. Following water immersion, a significant reduction in contraction stress was observed due to hygroscopic expansion. Applying a thin layer (approximately 25 µm) of composite and self-adhesive resin cements resulted in high levels of expansion stresses (over −6 MPa) after water aging.

Influence of Thermomechanical Loads on the Corrosion Behavior of Metal-Polymer-Joints

Metal-polymer-joints can be found in multiple today’s major applications like in hybrid car parts in terms of lightweight construction or molded electrical contacts for high-voltage applications. Common to both is the harsh environment they are exposed to including elevated temperature changes inducing thermomechanical stresses based on the differences of the CTE values as well as corrosive media like salty water, solvents or electrolytes. Each promotes its own corrosion mechanism that in most cases comes along with a degradation of the material’s and therefore the part’s performance in service. Especially, two mechanisms have to be considered when dealing with corrosion of metal-polymer-joints. Firstly, corrosion processes of metal and polymer can influence each other as well as the metal-polymer interface layer depending on the material combination. Secondly, thermomechanical stress due to temperature changes can also have an effect on the material’s corrosion behavior. Studying both mechanisms would help to improve the service time of hybrid parts.The work introduces a new method to investigate corrosion processes in metal-polymer-joints combining the influence of corrosive media and thermomechanical load. A hybrid specimen consisting of a specially formed metal inlay fully surrounded by a potting polymer is used for the measurements. When exposed to cyclic temperature load in a test chamber mechanical stress is induced in the polymer due to the different CTE of the materials. For the measurements typical material combinations used in lightweight construction and high-voltage applications are used. The hybrid specimens are exposed to thermal shocking cycles while being fully surrounded by corrosive media. Throughout the experiment, the specimens are constantly monitored using electrochemical impedance spectroscopy (EIS). In addition, a visual inspection of the specimens takes place after certain times to analyze the overall condition and possible cracks. As a reference, the same setup is applied only to the metal inlays used in the hybrid specimens. By interpreting the results of the EIS measurements, possible corrosion processes of metal and polymer as well as their correlation can be characterized in detail. Additionally, the comparison of hybrid specimens and raw metal inlays reveals the influence of the thermomechanical load on the corrosion process. The experimental part is supported by FE-simulations, which are also supplementary presented in this investigation.

Association Of Age, Gender and Teeth Distribution in Patients Undergoing Class I Metal Inlay Restoration

Association Of Age, Gender and Teeth Distribution in Patients Undergoing Class I Metal Inlay Restoration

The clinical findings and managements in 44 cases of cracked vital molars

Background/purposeThe aim of this study was to evaluate the associations between the clinical findings and managements in cracked vital molars that were caused by various factors including restoration and occlusion. Materials and methodsThe subjects' gender, age, chief complaint, type of tooth, percussion test results, pulp vitality, restoration material and cavity classification, clinical depth of the crack, evaluation of occlusion, depth of periodontal probing, and final management were recorded. ResultsA total of 44 vital cracked teeth (molars) were diagnosed in 40 patients. Regarding the type of tooth, a greater number of mandibular molars were affected than maxillary molars. Nonworking-side interference (NWI) was recognized in 38 cases (86.4%). Eight teeth (18.2%) had not been restored. Thirty-six teeth (81.8%) had been restored; 26 teeth (72.2%) with a metal inlay, 6 (16.7%) with an amalgam, and 4 (11.1%) with a composite resin. Regarding the final treatment in the endodontically-treated group, all 17 teeth were covered with a metal full crown. Regarding the final treatment in the pulp-reserved group, 19 teeth (70.4%) were covered with a metal full crown, and the other managements were as follows: occlusal adjustment (n = 4, 14.8%), composite resin (n = 2, 7.4%), and only follow-up without treatment (n = 2, 7.4%). All of the cases showed a good clinical prognosis. ConclusionThe NWI group restored with 58% of metal inlay accounted for more than 86% of the cracked teeth. Thus, in order to achieve a good outcome, cracked teeth, particularly those originating due to occlusal interference should be protected with coverage-type restorations.

A Study of the Metal Inlay Techniques Seen through the Institutional Prohibitions and Artisanship during the Goryeo Period

A Study of the Metal Inlay Techniques Seen through the Institutional Prohibitions and Artisanship during the Goryeo Period

Catastrophic Failure of a Metal-on-Metal Total Hip Arthroplasty Secondary to Metal Inlay Dissociation

Metal-on-metal bearing surfaces in total hip arthroplasty have been recently shown to have acceptable survivorship properties ( J Bone Joint Surg Am. 2006;88:1183; J Bone Joint Surg Am. 2006;88:1173), and they have certain advantages and disadvantages when compared to conventional metal-on-polyethylene bearing surfaces. Like traditional metal-on-polyethylene bearings, these metal-on-metal implants may also suffer from catastrophic failure. This case report represents an unusual situation in a 57-year-old man in which dissociation of a metal inlay in a metal-on-metal total hip arthroplasty resulted in articulation of the inferior aspect of the inlay with the femoral neck, leading to femoral neck notching, extensive periprosthetic soft tissue metallosis, osteolysis, and subsequent prosthetic catastrophic failure.

Bilateral simultaneous metal inlay dissociation from the polyethylene liner of a metal-on-metal hip replacement

Hard-on-hard bearings for total hip replacement may require a modular acetabular inlay for which polyethylene is often used in a sandwich-type configuration. However, differences in the elastic modulus of the materials make fixation of this metal insert uncertain. The aim of this study is to report a case of bilateral separation of the metal insert from the polyethylene sandwich in a metal-on-metal bearings prosthesis.A bilateral total hip arthroplasty was performed in two operations, four months apart, in a 53-year-old woman following a corticosteroid-induced osteonecrosis. The total hip replacement system included a cementless stem, and a press-fit hemispheric cup containing a polyethylene sandwich with a metallic insert (Sikomet).Three years later, the patient consulted because of abnormal noise in her right hip which appeared normal on conventional X-ray. Three months later she consulted again for persistent noise. Separation of the metal insert from the polyethylene sandwich was diagnosed and an acetabular revision was performed selecting a metal-on-polyethylene articulation system. The postoperative course, for this revision, was uneventful, but the patient returned with the similar symptoms in her left hip four months later, resulting in the same type of revision. During the revisions, osteolysis secondary to metallosis was diagnosed, requiring synovectomy and acetabular reconstruction with morcelized allograft impaction. The left side postoperative course included three dislocations in nine months which were conservatively treated and have not since recurred.This is the first reported case recording an almost simultaneous bilateral dissociation of a hard-on-hard inlay from its polyethylene sandwich. This bilateral case suggests that the fixation of the metal insert inside the polyethylene was probably defective. This case is also a reminder that mechanical complications (separation, implant fracture) should be searched for in presence of any abnormal noise occurring after hard-on-hard bearings prosthetic implantation. This confirms the necessity of periodical follow-up of hip arthroplasties and the importance of knowing their radiological features. The low carbon content of the Sikomet bearing may have been the cause of this failure by increasing frictional torque on the bearing surface, causing metallosis which has already been described in the literature in this type of hip replacement system.

口腔軟組織にインレーが迷入した2例

We report two rare cases of iatrogenic foreign bodies(inlay)in the upper lip and tongue induced during dental treatment.Case 1: A 48-year-old woman was referred to our hospital because of metal inlay impaction into the upper lip. The inlay could be touched from the oral side and was surgically removed without complications. Case 2: A 68-year-old woman was referred to our hospital because of a suspected foreign body in the mandible. An occlusal radiograph revealed a foreign body in the tongue. Inflammation was not present at the site of foreign body impaction. The foreign body was surgically removed without complications and was found to be inlay.

Clinical Survey on Type of Restoration in Deciduous Teeth

This study was conducted in 533 children with 1,634 treated teeth who visited the Pediatric Dentistry Department at the Chiba Hospital of Tokyo Dental College between January and December, 2003. Restorations on deciduous tooth were categorized by age of patient and tooth type. The following observations were made: Children aged 4 (17.9%) visited the clinic most frequently and this group had the highest number of deciduous restorations (21.3%). Among the 1,634 deciduous teeth restored, metal inlays were provided in 29.4% of total teeth restored, composite resin restorations in 27.2%, stainless-steel crowns in 25.7%, composite resin full crowns in 7.7%, glass-ionomer cement restorations in 6.6%, and amalgam restorations in 3.4%. By age, composite resin was most frequently used in children aged 1 to 3. In children aged 5 to 9, metal inlay was most frequently used. Those aged 4 received mostly stainless-steel crowns. Composite resin restorations were used mostly in anterior deciduous teeth, and metal inlays mostly in deciduous molars. Previous research indicated an increasing trend towards composite resin restorations and composite resin full crowns. The present study also confirmed such a trend. While the use of metal inlays and stainless-steel crowns tended to increase until 1987, the present study indicated a trend to decrease.

Survivorship and Retrieval Analysis of Sikomet Metal-on-Metal Total Hip Replacements at a Mean of Seven Years

Second-generation metal-on-metal total hip replacements were introduced in the early 1990s with the aim of eliminating polyethylene wear and the resulting complications of osteolysis and aseptic loosening. The goal of the present study was to evaluate the intermediate-term results in a series of patients who were managed with one of these implants. Between 1994 and 2002, we performed 640 total hip replacements in 591 patients with use of a Bicon-Plus cementless threaded cup with a polyethylene liner housing a metal inlay made of Sikomet low-carbon cobalt-chromium-molybdenum alloy that articulates with a Sikomet metal femoral head. Clinical and radiographic evaluation was performed retrospectively at a mean of 7.1 years postoperatively. Histologic analysis was performed on specimens retrieved from seventeen hips that were revised, and wear measurements were made for six hips that were revised. Thirty-four hips (thirty-four patients) were revised because of infection (six hips), aseptic loosening (twenty-three hips), pain without loosening (two hips), or other reasons (three hips). The survival rate of the prosthesis as a whole at ten years, with revision for any reason as the end point, was 0.91 (95% confidence interval, 0.88 to 0.95). The survival rate of the cup was 0.94 (95% confidence interval, 0.90 to 0.97), and that of the stem was 0.96 (95% confidence interval, 0.94 to 0.98). Linear or expansile osteolysis, or both, was observed on the radiographs of sixteen (64%) of the twenty-five hips that were revised because of aseptic loosening and/or pain. Histological analysis of pericapsular tissue was performed for seventeen of the twenty-five hips that were revised because of aseptic loosening and/or pain. Thirteen of these seventeen hips demonstrated a hypersensitivity-like reaction with aseptic inflammatory changes accompanied by moderate to extensive diffuse and perivascular infiltration of lymphocytes. In the six retrieved specimens that were subjected to wear analysis, the main wear mode was abrasive wear. The mean cumulative linear wear for the bearing was 31.3 microm, and the mean annual wear rate was 6.3 microm/yr. The mean clearance was 87.6 microm. After a mean duration of follow-up of seven years, aseptic loosening was the major reason for failure of Sikomet metal-on-metal prostheses. The histological findings and the prevalence of osteolysis suggest the possibility of a hypersensitivity-like immunological response to wear particles.

Dissociation of the metal inlay from the polyethylene liner in an uncemented threaded cup

We describe a case of spontaneous dissociation of the metal inlay from the polyethylene cup of a sandwiched metal-on-metal total hip prosthesis manufactured from Co-28Cr-6Mo SM 21 alloy. The patient, a 51-year-old active woman, started to feel groin pain 50 months postoperatively. The pain progressed after a slight trauma and led to final revision after 66 months in situ. No signs of impingement were observed. The polyethylene cup showed an approximately 2 mm-deep groove in the superior wall, and the head was heavily worn on the lateral side. In addition to the typically observed abrasive wear patterns, several types of severe wear defects were noticed. Extensive metallosis and necrosis were observed histologically. This unusual case of substantial deformation of the head and the cup was presumed to have occurred as a result of the increased friction and consequent high wear of the metal head.

The Artek cup for total hip replacement of dysplastic hip joints.

One specific difficulty in total hip replacement for developmental dysplasia of the hip is a shallow acetabulum with a short anteroposterior diameter. In a prospective cohort study we investigated the short-term results of the Artek cup, designed with a shallow outline and a height-reduced metal inlay for a large size 38 mm metal head, in a group of female patients with mild dysplasia of the hip. Fourteen consecutive patients with 17 dysplastic hip joints were included in the study. Their average age was 42 years. Fourteen hips had dysplasia Crowe grade I; 3 hips had dysplasia Crowe grade II. The femoral head centre was localized according to Pagnano in zone 1 in 3 cases, in zone 3 in 6 cases, and in zone 4 in 8 cases. The Harris hip score was 49 points (range 30-68 points). Mean follow-up was 20 months (range 14-24 months). The Harris hip score improved to a mean of 91 points (range 78-98 points). The postoperative radiographic measurements showed an inclination angle of 52.1 degrees (range 43-66 degrees ). The femoral head centre was in Pagnano zone 1 in 13 cases, in zone 2 in 1 case, in zone 3 in 1 case, and in zone 4 in 2 cases. The mean postoperative deviation from the approximative rotational centre was 0.17 mm (range -15 to 13 cm) in the superior direction and 5.3 mm (range -5 to 17 mm) in the lateral direction. In a small series of 17 implantations, stable press-fit fixation without screws or bone grafting was achieved despite acetabular defects. The complication rates were high. Inclination angles up to 54 degrees were not correlated with complications. Inclination angles of 60 degrees and more led to subtotal or complete dislocation. Mid-term results are still to follow concerning wear, dislocation rate, loosening and revision.

Cavity preparation for metal inlay by experimental tip for Er:YAG laser

The dental Er:YAG laser which is mainly used for dental hard tissue cutting was recently developed. In restorative dentistry, this laser has usually been used in composite resin restoration, but not for cast metal inlay restoration. This is because it is difficult to make the cavity form, such as retention form and convenience form, by using laser irradiation. At the 6th ISLD meeting, we reported an experimental chisel-shaped contact tip (ECSC tip) for use in cavity preparation for cast metal inlays. In this study, we examine a newly developed, modified experimental tip in inlay cavity preparation using an Erwin (ML22:HOYA & MORITA). This tip is composed of an arrangement of seven optical fibers having 0.2 or 0.3 mm diameter in a single row. The tooth-cutting efficacy of this tip was examined using extracted human and bovine teeth, and the irradiated sites were observed with SEM. The cutting efficacy of the experimental tip for both enamel and dentin was better than that of the ECSC tip. However, the surface flatness after cutting using experimental tip was poorer than the of the ECSC tip. It is suggested that inlay cavity preparation is possible using Erwin with this tip.

Effects of metal-inlay thickness in polyethylene cups with metal-on-metal bearings.

A way to prevent polyethylene wear in total hip replacements is to use metal-on-metal bearings. The cup design of these bearings may be a metal inlay in a polyethylene cup. However, these metal inlays are relatively thin and may deform on loading. The purpose of the current study was to determine whether these potential problems become actual for a realistic range of metal-inlay components having a thickness greater than 1 mm. For this purpose, the effects of thickness variation of a metal inlay in an ultrahigh molecular weight polyethylene cup were determined using three-dimensional finite element techniques. The results showed no indications for jamming of the bearing assuming a realistic inlay thickness (3-5 mm), even with a small clearance (25 microm). The metal inlay acted rigidly beyond a thickness of approximately 5 mm. Metal inlays thinner than 1.5 mm led to a considerable increase in contact area and a reduction in contact peak stress, which may be beneficial for the bearing performance. Currently, these thin liners have too many unknown characteristics and therefore the current authors recommend using rigid metal liners that have a thickness greater than 5 mm.

Posterior bridges retained by resin-bonded cast metal inlay retainers: a report of 60 cases followed for 6 years.

Between May 1989 and July 1994, 60 adhesive fixed partial posterior dentures retained by resin-bonded cast metal inlays were placed under controlled conditions. The influence of various prognostic factors on the event free and overall service duration was investigated with univariate and multivariate analysis. The majority of the failures (16 of 18) were caused by loss of adhesion at the metal cement interface and were observed either as debonding of the restorations completely or dislodgement of a single retainer. The other two failures appeared as secondary caries. Univariate analysis demonstrated that, retainer type, approximal configuration and dentine exposition had no effect on the event free service duration. On the other hand, gingival finishing level and luting agent were found to have an effect. Univariate testing was also conducted for the overall service duration and none of the variables were found to have an effect. Multivariate Cox Regression Analysis was performed to estimate the influence of categorical covariates: type of retainer, approximal preparation modification, gingival finishing level, preparation depth and luting agent on survival rates of event free and overall service duration. Luting agent was found to be the single independent prognostic variate (P < 0.0001) for the event free service duration and the other covariates were rejected. For overall service duration, none of the variables were found to be effective.

Posterior bridges retained by resin‐bonded cast metal inlay retainers: a report of 60 cases followed for 6 years

summary Between May 1989 and July 1994, 60 adhesive fixed partial posterior dentures retained by resin‐bonded cast metal inlays were placed under controlled conditions. The influence of various prognostic factors on the event free and overall service duration was investigated with univariate and multivariate analysis. The majority of the failures (16 of 18) were caused by loss of adhesion at the metal cement interface and were observed either as debonding of the restorations completely or dislodgement of a single retainer. The other two failures appeared as secondary caries. Univariate analysis demonstrated that, retainer type, approximal configuration and dentine exposition had no effect on the event free service duration. On the other hand, gingival finishing level and luting agent were found to have an effect. Univariate testing was also conducted for the overall service duration and none of the variables were found to have an effect, Multivariate Cox Regression Analysis was performed to estimate the influence of categorical covariates: type of retainer, approximal preparation modification, gingival finishing level, preparation depth and luting agent on survival rates of event free and overall service duration. Luting agent was found to be the single independent prognostic variate (P &lt; 0·0001) for the event free service duration and the other covariates were rejected. For overall service duration, none of the variables were found to be effective.

Current status of the cast metal inlay: a survey of dental schools in the UK and Hong Kong.

This study reports on the current status of the gold inlay in the undergraduate curriculum of Dental Schools in the UK and at the Prince Philip Dental Hospital, Hong Kong, to determine if the decline in the use of the cast gold inlay over the past 20 years is reflected in teaching at undergraduate level. A questionnaire, which was mailed to all the heads of departments of conservative dentistry in the UK, was designed to determine current teaching in respect of cast inlays. The results show that although the majority of UK dental schools continue to teach direct and indirect inlay techniques, a minority (4 and 5 respectively) no longer incorporate a practical exercise in this teaching. Reasons cited for the discontinuation of the technique are varied but the availability of simpler, more conservative techniques is emphasized. Examination of the treatment records at the Prince Philip Dental Hospital, Hong Kong, where the Class II inlay technique is taught both theoretically and practically, shows that only a small proportion of all posterior cast restorations fitted between May 1983 and April 1988 were inlays (4.6 per cent).

Qualification of Connectors Manufactured with Diffused Gold R156 Inlay Contacts

A qualification test has been performed to determine the long-term reliability of two inlay materials used in contacts for printed circuit board (PCB) connect0rs. The contacts were fabricated from diffused gold R156 (DGR156) and Western Electric No. 1 Metal (# 1) inlay materials.. The qualification of the DGR156 inlay materials is especially important, since implementation of this material system results in a considerable cost reduction for this family of PCB con~ nectors. The performance of the two inlay materials was compared against a hard gold electroplated finish. The contact was tested in a mated condition against gold-p!ated 0.025-in square coined backplane :pins. Test samples were subjected to two wear levels of 50 and 200 insertion/withdrawal cycles. Different sets of test contacts were then submitted to a wear evaluation, mechanical vibration test, andthe following accelerated aging tests: high humidity with temperature cycling, thermalaging, temperature cyel!ng, and two BTL corrosion gas tests. Theresults of the wear evaluation, mechanical tests, and accelerated aging tests show satisfactory performanc9 for the contact system. Thus we have recommended that DGR156 inlay material be substituted for the Co hardened Au finish used inthe PCB family of connector codes. This will result in considerable cost savings without significant decrease in reliability