Based on the investigation and analysis of the current situation for hearing aid fitting, some analysis results and suggestions for the development of the industry are presented, including manufacturer, association for medical devices industry and supervision division.
Health Care Sector ; Hearing Aids ; Prosthesis Fitting ; methods

At present, foreign standard knee joint prosthesis is mostly used in clinical practice; it can well represent the biological characteristic of knee joint on human being. So this paper adopts the reverse engineering technology in that connexion, presents novel positioning method of acquiring the point data on the surface of knee joint prosthesis, puts forward the algorithm of three-point angle method for removing the noise error and correcting the noise error based on the least squares plane to smooth point cloud. And then, the surface of knee joint prosthesis with better accuracy and smoothness can be generated. Finally, the knee joint prosthesis model can be generated. Thus, a basis is provided for the localization of knee joint prosthesis. This new algorithm is mainly used for the surface modeling based on point cloud smoothing, including the surface of knee joint prosthesis, the surface of regular shape, and the surface with gentle change in curvature.
Computer-Aided Design ; Humans ; Knee Joint ; anatomy & histology ; surgery ; Knee Prosthesis ; Prosthesis Design ; methods ; Prosthesis Fitting ; methods

In order to reduce the test time in real ear hearing-aid fitting for children, the validity of applying the average real ear to coupler differences (RECDs) in prefitting procedure using a 2cc coupler measurement system was evaluated by checking whether the majority of people's RECDs might occur within 5 dB of the average RECDs (N = 116) in each test frequency and age group. The percentages of occurrence were around 90% in test subjects' RECDs in saturation sound pressure levels (SSPLs) and around 70% in gain in each important test frequency. Appropriate test frequencies in prefitting are 500, 1000, 1500 and 2000 Hz.
Adolescence ; Adult ; Aged ; Child ; Child, Preschool ; Ear ; Hearing Aids* ; Human ; Infant ; Middle Age ; Otolaryngology/methods* ; Otolaryngology/instrumentation* ; Prosthesis Fitting/methods* ; Time Factors

OBJECTIVETo compare the influence of different investment materials, methods and crown height on the cast shrinkage of full crowns made of dental base metal alloy.

METHODSAll of the 288 wax patterns were made and divided into three groups according to their crown height. In every group, wax patterns were invested in metal rings and paper rings with three types investment material and cast with base metal alloys. Then the inside diameters of castings were measured and analyzed by statistical package SPSS.

RESULTSDifferences between groups invested with the three types of material were significant(P < 0.01). There were significant difference between the groups investing with metal rings and paper rings(P < 0.01).

CONCLUSIONThe component of investment material and invested ring can affect the cast shrinkage of dental base metal alloy apparently.

Crowns ; standards ; Dental Alloys ; standards ; Dental Casting Investment ; Dental Casting Technique ; instrumentation ; Humans ; Inlay Casting Wax ; chemistry ; classification ; Materials Testing ; instrumentation ; methods ; Metal Ceramic Alloys ; standards ; Prosthesis Fitting

Despite advances in surgical techniques and instrumentation, current intra-operative estimations of acetabular version in total hip arthroplasty are of limited accuracy. In the present study, two experienced orthopedic surgeons compared intra-operatively measured (using portable imaging) anteversions and vertical inclinations of acetabular components with those measured using standardized radiographs post-operatively in 40 patients. Of the all vertical inclinations measured from intra-operative radiographs, 72.5% (n=29) were within +/-2degrees, and 97.5% (n=39) were within +/-5degrees of those determined using post-operative radiographs, and for anteversion, 52.5% (n=21) were within +/-2degrees, and 97.5% (n=39) were within +/-5degrees. Post-operative radiographs demonstrated that 90.0% (n=36) of vertical inclinations and anteversions were within the adequate zone. Obviously, our method has its limitations, but the authors conclude that the method described in this article better allows surgeons to verify acetabular version intra-operatively. In particular, the described method is suitable in cases with a deformed acetabular anatomy and difficult revision surgery.
Acetabulum/radiography/*surgery ; Adult ; Aged ; Aged, 80 and over ; *Arthroplasty, Replacement, Hip ; Female ; Hip Joint/*radiography/surgery ; Hip Prosthesis ; Humans ; Imaging, Three-Dimensional/methods ; Intraoperative Care/*instrumentation/methods ; Male ; Middle Aged ; Prosthesis Fitting

Size selection of the laryngeal mask airway (LMA) Classic based on actual body weight remains a common practice. However, ideal body weight might allow for a better size selection in obese patients. The purpose of our study was to compare the utility of ideal body weight and actual body weight when choosing the appropriate size of the LMA Classic by a randomized clinical trial. One hundred patients with age 20 to 70 yr, body mass index > or =25 kg/m2, and the difference between LMA sizes based on actual weight and ideal weight were allocated to insert the LMA Classic using either actual body weight or ideal body weight in a weight-based formula for size selection. After insertion of the device, several variables including insertion parameters, sealing function, fiberoptic imaging, and complications were investigated. The insertion success rate at the first attempt was lower in the actual weight group (82%) than in the ideal weight group (96%), even it did not show significant difference. The ideal weight group had significantly shorter insertion time and easier placement. However, fiberoptic views were significantly better in the actual weight group. Intraoperative complications, sore throat in the recovery room, and dysphonia at postoperative 24 hr occurred significantly less often in the ideal weight group than in the actual weight group. It is suggested that the ideal body weight may be beneficial to the size selection of the LMA Classic in overweight patients (Clinical Trial Registry, NCT 01843270).
Adult ; Aged ; *Body Weight ; Equipment Design ; Female ; Human Engineering/*methods ; Humans ; Ideal Body Weight/*physiology ; Laryngeal Masks/*classification ; Male ; Middle Aged ; Overweight/*physiopathology ; Prosthesis Fitting/*methods ; Reproducibility of Results ; Republic of Korea ; Sensitivity and Specificity ; Young Adult

OBJECTIVETo evaluate the long-term changes in the quality of life (QOL) scores in elderly patients after aortic valve replacement, and assess the impact of prosthesis-patient mismatch on the QQL of the patients.

METHODSA prospective cohort study was conducted involving 100 consecutive elderly patients above 70 years of age, who underwent isolated aortic valve or simultaneous aortic valve-coronary artery bypass graft (CABG) procedures between August 10, 1995 and August 19, 1998. Patient-prosthesis mismatch (PPM) was defined as a prosthetic aortic valve EOAI of 0.85 cm2/m2 or less. The clinical follow-up examinations were carried out at 4 weeks and 6 months after the operation, and then annually afterwards. Cumulative and comparative analyses of the long-term outcomes and gradient pressure of the prosthetic valve were performed. The QOL of the patients was evaluated using the Short Form 36-Item Health Survey (SF-36) questionnaire.

RESULTSThe mean age of the patients at prosthesis implantation was 74.7-/+5.7 years (range 70-87 years). The patients were followed up for a mean of 7.3-/+4.5 years. The thirty-day mortality was 6.3% in the mismatch group, and 3.3% in the matching group. The freedom from death showed no significant difference between the two groups at the first, third and fifth years after the prosthetic implantation, but differed significantly at the seventh year. The echocardiographic data showed significant differences in the mean gradient pressure between the two groups at the first and fifth years postoperatively. At most of the time points for follow-up examination, the general health and energy/vitality of the patients all improved from the preoperative levels, but no significant improvement was found at the third, fifth, and seventh years in the role emotional, social role, or general mental health; at the first postoperative year, however, the role emotional, social role, and particularly mental health, presented with significant improvements in comparison with the preoperative levels. No obvious difference in the QOL was noted between the two groups at the time points of observation.

CONCLUSIONSAortic vale replacement improves the QOL of the elderly patients, but the degree of improvements do not seem to be influenced by PPM. The interpretation of the impact of PPM on the clinic outcome of the patients still remains controversial.

Aged ; Aged, 80 and over ; Aortic Valve ; physiopathology ; surgery ; Aortic Valve Insufficiency ; surgery ; Aortic Valve Stenosis ; surgery ; Bioprosthesis ; Female ; Heart Valve Prosthesis ; Heart Valve Prosthesis Implantation ; methods ; Humans ; Male ; Postoperative Period ; Prospective Studies ; Prosthesis Design ; Prosthesis Fitting ; adverse effects ; Quality of Life ; Ventricular Dysfunction, Left ; physiopathology