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At least 613 records · Page 34Linked to original sources
PubMed2005

Removable rigid dressings versus soft dressings: a randomized, controlled study with dysvascular, trans-tibial amputees.

This study compares a standard soft dressing (SSD) with a removable rigid dressing (RRD) in a randomized, controlled trial using 50 dysvascular trans-tibial amputees. Both dressing types were applied immediately post-operatively and were only removed for wound dressing changes. Half the subjects were allocated prospectively by ballot to either the RRD group or the SSD group. There was a strong trend indicating that primary wound healing of the stump occurred almost 2 weeks earlier in subjects using the RRD (RRD = 51.2 days +/- 19.4; SSD = 64.7 days +/- 29.5; P= 0.07; RRD: n =17; SSD: n = 14.) There were no significant differences between the other parameters measured which included time to prosthetic fitting, length of hospital stay, incidence of stump breakdown, and time taken for stump volume to stabilize. The incidence of stump damage due to falls was also recorded, the results indicating that RRDs may protect the new stump from trauma.

Aged↗
PubMedDate not supplied

Marginal adaptation of fixed prosthodontics: a new in vitro 360-degree external examination procedure.

PURPOSE: This study evaluated the marginal fit of experimental and custom-made fixed prosthetic restorations through a new 360-degree external examination. The minimum number of gap measurements required to produce relevant results for gap analysis was also investigated. MATERIALS AND METHODS: The marginal fit of six experimental and eight custom-made crowns was observed microscopically by means of a mechanical device, and software was employed to measure the gap. Two crowns, chosen from among the 14 previously evaluated, were reanalyzed to determine the minimum number of gap measurements required to produce significant results for gap analysis. RESULTS: The precision obtained with the custom-made crowns differed from that of the experimental specimens. The minimum number of measurements required to produce a sample mean value within +/- 5 microm of the mean, calculated over 360 measurements, taking standard error of the means < or = 4 microm, was 18 for experimental and 90 for custom-made crowns, for both equidistant measurement spacing and randomly selected points. CONCLUSION: Differences in fit between experimental specimens and custom-made ones showed that experimental results might not always be obtained in clinical practice. Within the limitations of the protocol of this study, the minimum number of measurements required to ensure relevant results for gap analysis was 18 for experimental and 90 for custom-made crowns.

Crowns↗
PubMed1996

The effects of superstructure fit and loading on individual implant units: Part 2. The effects of loading a superstructure with varying degrees of fit.

This study investigated force transmission in an implant supported bridge with varying degrees of fit. The project utilised an in vitro model of five implant fixtures mounted linearly and rigidly. These supported a well-fitting cast gold superstructure via implant abutments fitted with strain gauges so as to function as force transducers. Gaps of 10-110 microns were created at the middle and one terminal abutment and loads of 50N applied over the cantilever and 230N between the terminal abutments. Force distribution was uneven, compression, tension and torque observed, and loading of the cantilever noted to generate large forces.

Bite Force↗
PubMedDate not supplied

Comparison of marginal fit of 3 different metal-ceramic systems: an in vitro study.

PURPOSE: The aim of this study was to compare the marginal adaptation of metal-ceramic crowns made with 3 different metal substructures. MATERIALS AND METHODS: Seventy-five gypsum dies were fabricated from a master steel die. They were randomly divided into 3 groups of 25 dies each. A metal coping was prepared on each die using a different technique for each group: composite alloy, electroforming, and cast high-noble alloy. Ceramic was baked on all of the samples following the same protocol and simulating the shape and size of a maxillary central incisor. All specimens were evaluated under a stereomicroscope at 200x magnification. The marginal gap was measured at 8 different points on each specimen before and after ceramic application and also on the master steel die. A total of 3,600 measurements was evaluated. The results were statistically elaborated by means of a t test and one-way analysis of variance (ANOVA). RESULTS: The ANOVA revealed a significant difference in mean marginal gap before and after ceramic application within each group. Electroforming (mean 32 microns) and high-noble alloy (mean 31 microns) showed better marginal fit after ceramic application and on the master steel die compared to composite alloy (mean 68 microns; P < 0.0001). CONCLUSION: Marginal gaps are influenced by the application of ceramic and by the alloy used for the substructure, and the values obtained were within the limits of clinical acceptability (70 microns).

Analysis of Variance↗
PubMed2001

Verifying loudness perception after hearing aid fitting.

During the verification phase of a hearing aid fitting, clinicians often want to assess the extent to which loudness perceptions for amplified sounds are similar to those typical of normal hearers. This type of verification calls for a criterion for "normal" loudness perception of sounds presented in a sound field. This research sought to answer several questions about the parameters of a valid "normal" criterion for a verification procedure using the Contour test of loudness perception. Loudness data were obtained from 30 listeners with normal hearing. Results indicated that a loudness growth function obtained with earphone listening is not an appropriate normative reference for hearing aid fitting verification. Instead, the normative data should be based on sound field listening. Results also indicated that the same normative function could be used to assess both unilateral and bilateral fittings. Further, it is likely that the same normative function can be used for most frequency responses that are likely to be used in feasible fittings. Finally, it was found that a previously published normative function obtained using an automated test procedure was not faithfully replicated using a carefully executed fully manual test procedure. We concluded that, until a replicable normative function is established, practitioners will need to generate their own local norms to perform postfitting verification of loudness normalization.

Adult↗
PubMed1994

Effects of fit and bonding characteristics of femoral stems on adaptive bone remodeling.

Bone atrophy caused by stress-shielding may cause serious complications for the long-term fixation of hip stems. In particular, uncemented total hip arthroplasty is threatened by this problem, because the stems are usually larger and, as a consequence, stiffer than those of cemented implants. In the present study, the effects of fit and bonding characteristics of femoral hip stems were investigated, using the (nonlinear) finite element method in combination with adaptive bone remodeling theory to predict the bone density distribution in a bone or bone/implant configuration. Unknown parameters used in the theory, such as a reference equilibrium loading stimulus and a threshold (dead) zone of this stimulus, were established (triggered) by using the method to predict the density distributions in the natural femur and around fully coated uncemented implants. The computer simulation method can provide long term predictions of remodeling patterns around various implant configurations. Several cases were analyzed, whereby the coating conditions (fully, partly, or noncoated) and the fit characteristics (press fitted or overreamed) were varied. The computer predictions showed that partly coating can only significantly reduce bone atrophy relative to fully coated stems, when the coating is applied at a small region at the utmost proximal part of the stem. For smooth press-fit stems the predicted amount of bone loss (35 percent in the proximal medial region) was less than for a one-third proximally coated or a fully coated stem (50 to 54 percent predicted bone loss in the proximal medial region).(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed2004

Trends in cochlear implants.

More than 60,000 people worldwide use cochlear implants as a means to restore functional hearing. Although individual performance variability is still high, an average implant user can talk on the phone in a quiet environment. Cochlear-implant research has also matured as a field, as evidenced by the exponential growth in both the patient population and scientific publication. The present report examines current issues related to audiologic, clinical, engineering, anatomic, and physiologic aspects of cochlear implants, focusing on their psychophysical, speech, music, and cognitive performance. This report also forecasts clinical and research trends related to presurgical evaluation, fitting protocols, signal processing, and postsurgical rehabilitation in cochlear implants. Finally, a future landscape in amplification is presented that requires a unique, yet complementary, contribution from hearing aids, middle ear implants, and cochlear implants to achieve a total solution to the entire spectrum of hearing loss treatment and management.

Acoustic Stimulation↗
PubMed2002

Opting for two hearing aids: a predictor of long-term use among adult patients fitted after screening.

This study is a follow-up of patients fitted with one or two hearing aids, approximately 10 years previously. Our patients were identified through population screening for hearing difficulties when they were aged 50-65 years. At the time, they had a trial of unilateral and bilateral fittings, and then they made their own choice to keep one or two aids. We found that 10 of the 12 who had opted for two aids and were available for follow-up 10 years later continued using at least one aid (83%, 95% CI 55-95). Six of the 17 who opted for unilateral fitting and were available for follow-up used a hearing aid in the long term (35%, 95% CI: 17-59%). Therefore, this study suggests that people who are identified through population screening, are bilaterally impaired, are willing to try bilateral fitting, and choose to continue with two aids, are likely to become long-term users of (one or two) hearing aids. Those who choose to continue with one aid after a trial of bilateral fitting are at high risk of rejecting the aid in the long term. Our sample is small, and we took a number of steps in the analysis in order to clarify whether these findings are reliable. We could not identify any confounding factors. The patients' preference for continuing with bilateral or unilateral aids after fitting was the only predictor of long-term use in our sample. Remarkably, bilateral preference was a better predictor of long-term use than the degree of hearing impairment. We discuss how this study provides useful information for planning population screening for hearing difficulties in middle age.

Aged↗
PubMed1993

Thigh pain in cementless total hip replacement.

The incidence of thigh pain was investigated in 51 joints implanted with model Y or YII cementless total hip system. The 51 patients were followed for one or more years after surgery. Twenty-six out of 51 implanted with the model Y, and the other 25 with the model YII. Thigh pain appeared in 11 out of 26 patients (43%) replaced by model Y and in only 2 out of 25 (8%) replaced by model Y II. The difference in the incidence of thigh pain was attributed to the difference in the extent of the press fit of the stem, stress distribution and postoperative activity. To prevent thigh pain, a favorable press fit must be achieved during surgery, and the excessive weight-bearing must be restricted in postoperative course. In our improved stem design, stress is distributed uniformly on the interface between the bone and the stem resulting in reduction of thigh pain.

Adult↗
PubMed2002

Contact lens fitting to correct irregular astigmatism after corneal refractive surgery.

PURPOSE: To study a technique of contact lens fitting and its visual results in patients with irregular astigmatism induced by corneal refractive surgery. SETTING: Department of Cornea and Refractive Surgery, Instituto Oftalmológico de Alicante, Alicante, Spain. METHODS: This prospective noncomparative study comprised 29 eyes with irregular astigmatism after corneal refractive surgery. Different types of contact lenses were used to correct the astigmatism: hard, gas permeable, hybrid, and toric hydrophilic. Preoperative and postoperative data were analyzed for proper fitting including the preoperative keratometeric reading and corneal ablation zone. RESULTS: Proper contact lens fitting was achieved in 23 eyes (79.3%). In 6 eyes (20.7%), fitting was not possible despite an improvement in best corrected visual acuity (BCVA). Of the eyes with proper fitting, 14 (60.9%) had rigid gas-permeable lenses (9.80 mm), 6 (26.1%) had hydrophilic lenses (14.00 mm), and 3 (13.0%) had hybrid lenses (14.3 mm). Comparing the BCVA with that with spectacles, 23 eyes (79.3%) gained 2 lines or more of BCVA, 4 (13.8%) gained 1 line, and 2 (6.9%) maintained the same acuity as with spectacles. No eye lost lines of BCVA. CONCLUSIONS: Results indicate that contact lens fitting is a good-and sometimes the only-alternative for patients with induced irregular astigmatism. Rigid gas-permeable contact lenses provided the best visual performance and patient tolerance.

Adult↗
PubMed1998

[Hearing aid fitting in children treated at the Phoniatric Outpatient Clinic in Zabrze in years 1986-1990].

The purpose of this study was to evaluate the hearing aid fitting of 179 regularly controlled, hearing-disabled children from the Silesian area, first time admitted to Phoniatric Outpatient Clinic in Zabrze in years 1986-1990. The mean age of provision of a hearing aid was high. Children were supplied with hearing aids at mean age of 4,9 years (losses > 60 dB) and of 9,3 years (losses < or = 60 dB). There was a delay from 8,4 up to 12,5 months (losses < or = 60 dB) between the age of fitting and the issue of the hearing aid. It was also stated that the total amount of children wearing their aids binaurally decreased significantly from 118 to 74 during 5 years' period. As for the utilisation of hearing aids, prevalence of full-time users (57.9%) was demonstrated in confrontation to non-users (5.6%).

Adolescent↗
PubMed2005

A clinical evaluation of the clinical remount procedure.

One hundred patients were treated with complete dentures. The patients were divided into two equal groups; the first group (50 patients) received complete dentures and a clinical remount procedure was performed, while the second group received complete dentures without a clinical remount. A four point, nine scale Patient Denture Satisfaction questionnaire was used to evaluate the patients' satisfaction with their dentures. When the clinical remount procedure was used, results have shown a highly significant improvement in the comfort of the upper dentures and in the fit and comfort of the lower dentures. There was a significant improvement in the chewing ability as well. In conclusion it is highly recommended the clinical remount procedure be used because it improves the patient's satisfaction with their dentures in many important aspects as shown in this study.

Aged↗
PubMed2003

Overnight orthokeratology: visual and corneal changes.

PURPOSE: To achieve an optimal fit with reverse geometry Contex OK lenses and to determine a time course for and the stability of visual and corneal changes in achieving maximal refractive, corneal curvature, and corneal thickness changes after overnight wear of OK B and D series lenses. METHODS: This investigation was conducted under an Food and Drug Administration IDE G000059. Both eyes of 10 subjects were fitted with the lenses, and uncorrected visual acuity, refractive correction, contrast sensitivity, corneal curvature, and corneal thickness were measured at baseline and at 1 day, 1week, 1 month, and 3 months after lenses were worn. Except for baseline, data were collected at four different times during the day, immediately following lens removal and 4, 8, and 12 hours after lens removal. RESULTS: The results from eight subjects showed that uncorrected visual acuity, refractive correction, contrast sensitivity, and corneal curvature all changed significantly (P=0.01) overnight. By the end of 1 week, all corneal and visual changes had reached a maximal level and remained fairly stable during the day. These changes were sustained at 3 months. The epithelial thickness data from four subjects showed that the corneal epithelial thickness was reduced by approximately 19 microm after 3 months of lens wear. CONCLUSIONS: Successful fitting of OK B and D series lenses requires a thorough understanding of the lens-cornea relationship. Full effect of overnight orthokeratology is achieved by the end of 1 week. The visual and corneal changes remain stable for all waking hours of the day and allow patients to enjoy excellent device-free vision (20/20).

Adult↗
PubMed2003

RK4 (reverse-geometry) contact lens fitting after penetrating keratoplasty.

PURPOSE: We evaluated the performance of the RK4 (reverse-geometry) contact lens in patients with flat central and steep peripheral corneal topography after penetrating keratoplasty (PK). METHODS: A retrospective study was performed of post-PK patients fitted with RK4 lenses on the Cornea Service at Wills Eye Hospital, between March 2000 and February 2002. RESULTS: Fifteen eyes of 13 post-PK patients were fitted with RK4 lenses and monitored for more than two months (range, 2.1-23.5 months; mean, 8.1 +/- 7.0 months). The average number of lens refits per eye was 1.0 +/- 1.2 (range, 0-4). Ninety-three percent (14/15) of the eyes that were fitted achieved at least 20/30 visual acuity, and 53% (8/15) of eyes achieved 20/20 visual acuity. A comparison of prefitted and post-fitted corrected visual acuity demonstrated a statistically significant improvement (P < 0.01). RK4 lenses were successfully worn full time or part time in all cases. CONCLUSIONS: The RK4 lens can provide well-tolerated visual correction in cases with central flat, peripheral steep corneal contour following PK.

Adult↗
PubMed2005

Over-the-counter decorative contact lenses: Cosmetic or Medical Devices? A Case Series.

PURPOSE: To illustrate the implications of the unauthorized sale and unmonitored wearing of decorative cosmetic contact lenses resulting in ocular complications and to determine the prevalence of the use of cosmetic contact lenses obtained from unlicensed providers by adolescents. METHODS: Observational case report, structured interview, and survey in a retrospective, observational, clinical practice setting. Reported sources of contact lenses were categorized as provider and nonprovider, and associations within the data were reviewed by using a Pearson correlation and chi-square test. RESULTS: Twelve patients (eight female and four male) were seen urgently for acute eye pain and redness after wearing plano decorative contact lenses. None of the patients had previously worn a contact lens. None of the lenses were dispensed by eye care professionals. Four patients developed blinding infections requiring hospital admission. Causative organisms included staphylococci, Pseudomonas, and acanthamoeba. One patient required a penetrating keratoplasty. One hundred fifty-nine patients were surveyed. Thirty-seven (23%) used decorative contact lenses. Lenses were obtained from an unlicensed provider 51% of the time. Education about lens care and handling was significantly associated with acquiring lenses from licensed providers (R = 0.74, P < 0.0001). CONCLUSIONS: Colored noncorrective contact lenses are being dispensed without a prescription or fitting from unlicensed vendors. Patients who acquire lenses from unauthorized providers are significantly less likely to be instructed on appropriate lens use and care. Consequently, uninformed lens wearers are experiencing acute vision-threatening infections and inflammation.

Adolescent↗
PubMed2003

Computer aided design of large-format prefabricated cranial plates.

The authors' objective in this project was to replace current state-of-the-art manual methods for preoperative production (i.e., prefabrication) of large-format (>100 cm2) cranioplasties with a system for computer-aided design and direct computer-aided manufacture of the implant's shape. This system uses standard 3D CT data, requires no specialized training, and produces an accurately fitting cranioplasty that can be recast in the physician's material of choice (e.g., polymethylmethacrylate [PMMA] or pre-bent titanium plating). The authors begin by locating the cranial defect margin on a skull surface image generated from a 3D head CT-scan. A right-to-left mirrored or average 3D skull surface template image is then fit to the patient's skull surface image. The area around the defect is cut out and stitched to the previously isolated defect margin. This defect-filling surface is then tapered and 3D printed. The 3D printed implant model is then recast in a biocompatible material. Manually generated cranial implants produced for five patients were compared with implants resulting from this new computer-based method. All five computer-generated implants were better fitting and more cosmetically suitable than the manually generated skull plates received by these patients. These well-fitting implants are more likely to protect the brain from trauma and infection. Therefore, the authors conclude that their new production method provides a better result with less expense than current methods for preoperative or intraoperative fabrication of large-format cranioplasties.

Adult↗
PubMed2005

The tapered press fit total hip arthroplasty: a European alternative.

The tapered rectangular press fit femoral component design of Karl Zweymüller remains highly successful since its inception in 1979. The longitudinal taper and rectangular cross-section provide unequaled primary stability, which promotes consistent secondary osseointegration to the grit-blasted titanium surface, even in osteoporotic bone. The "fit without fill" concept provides for bone conservation and preservation of the intraosseous blood supply by compaction, rather than removal, of the metaphyseal cancellous bone. The surgical technique is simple and forgiving, allowing for infinite adjustability in stem height and anteversion. Numerous long-term studies report excellent clinical results with a negligible incidence of loosening, thigh pain, osteolysis, or significant stress shielding and survivorships approaching 100% at 10 years.

Arthroplasty, Replacement, Hip↗
PubMed2002

Effect of lens base curve on subjective comfort and assessment of fit with silicone hydrogel continuous wear contact lenses.

PURPOSE: To study the effect of base curve on subjective comfort of silicone hydrogel extended wear lenses. METHODS: Ninety-five subjects were first trial fitted with 8.6-mm base curve lotrafilcon A (Focus Night & Day) lenses and then with 8.4-mm lenses only if poor subjective comfort or poor fit was present. Comfort and fit were assessed after 15 min. Subjects with discomfort or signs of poor fit were then trial fitted with 8.4-mm lenses. RESULTS: Of 190 eyes, 74.2% were fitted with 8.6-mm lenses, and 23.7% required 8.4-mm lenses. Two (2.1 %) subjects could not be fitted with either base curve. Mean steep keratometry (K) reading for eyes dispensed with 8.6-mm lenses was 43.88 D and 45.56 D for eyes dispensed in the 8.4-mm lenses (p < 0.001). CONCLUSIONS: A clinically useful criterion showing the need for 8.4-mm lenses was steep K of > or = 45.50 D; 77% of these eyes required the steeper lens for good comfort and fit. Subjective discomfort with 8.6-mm lenses was also a useful signal for the need of a steeper lens; mean comfort scores for those subjects rose from 6.33 with 8.6-mm lenses to 9.44 with the 8.4-mm lenses for eyes requiring the steeper lens (p < 0.001).

Adult↗