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At least 685 records · Page 38Linked to original sources
PubMed2006

Bone remodeling is different in metaphyseal and diaphyseal-fit uncemented hip stems.

Femoral component stability in uncemented total hip arthroplasties depends on periprosthetic bone remodeling. Stem design is an important factor influencing bone remodeling, however the design that promotes the most bone remodeling is unclear. We examined metaphyseal and diaphyseal-fit stems to determine the effect of stem design on bone remodeling and stability. Twenty-three patients who had total hip arthroplasties (28 hips) with metaphyseal-fit stems were matched with 27 patients (32 hips) who had uncemented total hip arthroplasties with diaphyseal-fit stems. We assessed preoperative radiographs for canal fill, canal shape, and bone quality. We then assessed postoperative radiographs for periprosthetic bone remodeling including spot welds, cortical hypertrophy, and pedestal formation. Patients were examined clinically using a modified Harris hip score. Patients with metaphyseal stems had increased cortical hypertrophy 1 year postoperatively. However, there was no functional difference 2 years postoperatively. Both stem designs resulted in bone remodeling by 2 years postoperatively with similar clinical results.

Adult↗
PubMed1995

Granular dystrophy of the cornea. Contact lens fitting after phototherapeutic keratectomy.

We performed a phototherapeutic keratectomy using excimer laser 193-nm ablation in a patient with granular dystrophy of the cornea. The hyperopic shift caused by the 5-mm diameter tissue ablation could effectively be corrected by a high oxygen-transmissible, aspheric, rigid contact lenses 1 week after treatment. Corneal topographic analysis was used to monitor the changes in corneal shape after excimer treatment. The 3.5-D hyperopic shift did not change after 4 months, but corneal shape altered during this period. It was not necessary to adjust lens parameters. The central corneal area was clear, and visual acuity improved from 20/40 to 20/20.

Adolescent↗
PubMed1985

Temporary above-knee prostheses and training programme during chemotherapy.

A temporary prosthesis has been developed for above-knee amputees who receive long-term post-amputation chemotherapy. The temporary prosthesis has an adjustable laminated quadrilateral socket, the size of which is adjusted by metal screws. Fifteen patients were fitted with the temporary prosthesis. Initial fittings were carried out after a period averaging 46 days from amputation. All of the patients were able to walk with one crutch after about one month from initial fitting. Although patients often had to discontinue their prosthetic training owing to chemotherapy, they could resume wearing their prostheses simply by adjusting the socket. One patient, who was fitted with a cosmetic ultra-light prosthesis initially due to her poor general condition, was later fitted with the temporary prosthesis. She regained the ability to walk 60 days later and still wears it. Early fitting of temporary prostheses for these patients is not only of practical convenience but also improves their mental state.

Adolescent↗
PubMed1994

Effect of Ca/P coating resorption and surgical fit on the bone/implant interface.

The effect of coating resorption on bone apposition and attachment strength to resorbable hydroxyapatite (HA), nonresorbable HA-coated, and uncoated rough titanium implants was evaluated in interference- and noninterference-fit (gap of 2-3 mm) surgical models 2, 4, and 12 weeks postoperatively. Interference and noninterference fits showed differences in bone bridging. Bone apposition was circumferential around the implants in noninterference fit. Significantly greater bone apposition was seen to nonresorbable HA-coated implants than uncoated and resorbable HA-coated implants at 4 and 12 weeks. Only resorbable HA coatings showed significantly lower bone apposition for noninterference versus interference fit and from 4-12 weeks. At 2 weeks, strengths of bone attachment to resorbable HA-coated implants were greater than the other implants, and decreased to lower values (not significant) than the nonresorbable HA-coated implants at 4 and 12 weeks. Differences in push-out shear strengths between interference- and noninterference-fit surgical models were significant for uncoated implants at 4 weeks, but not for HA-coated implants at any time period. Significant differences were seen between the three implant types only for the noninterference-fit model, where the HA-coated implants showed greater strengths than the uncoated implants (significant at 2 and 4 weeks). This study showed that presence of resorbable or nonresorbable HA coatings is beneficial when a gap of 2-3 mm is present between the implant and the bone. The resorbable HA-coated implants showed greatest strengths at the early time period. At later time periods, resorbable HA-coated implants showed lower bone apposition and attachment strengths than nonresorbable HA coatings.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium↗
PubMed1996

Effects of improvements of poorly fitting dentures and new dentures on patient satisfaction.

Clinicians reline or replace dentures to improve occlusion, stability, retention and facial support. They believe that well-fitting dentures will maintain supporting tissues in good health and satisfy patients by improving oral function and self-esteem. In this study, satisfaction of 21 patients with poorly fitting dentures was assessed before and after the dentures were modified to improve occlusion, vertical dimension of occlusion, and retention and stability or the dentures were replaced with new ones. More than 55% of the patients were moderately to fully satisfied with their poorly fitting dentures. Most patients perceived improvements in chewing comfort, chewing ability, eating enjoyment, food choices, security, and speech after each denture modification and with new dentures. The relative importance of the four sequential modifications could not be determined because they were made sequentially and their effects became cumulative. Chewing ability, eating enjoyment, particles under dentures, and food choices were highly correlated with chewing comfort and overall patient satisfaction. The results support the belief of many clinicians that patients benefit from relining of poorly fitting dentures or replacement with new dentures. Improvements in chewing function were perceived by most patients despite the lack of improvement in masticatory performance or masseter muscle activity with modified or new dentures. It is likely that denture wearers perceive chewing ability in terms of chewing comfort rather than ability to comminute food, an objective measure of chewing performance. The latter is not altered markedly by the clinical excellence of dentures.

Adaptation, Physiological↗
PubMed2006

Incidence of rigid gas-permeable contact lens wear after keratoplasty for keratoconus.

PURPOSE: To review retrospectively the charts of all 190 patients who underwent penetrating keratoplasty for keratoconus in one hospital during a 5-year period (1995-2000), with special attention paid to contact lens fitting. METHODS: The frequency of postoperative contact lens use, the time to fit lenses after grafting, tolerance and visual acuity, and postoperative risks for the graft were studied. RESULTS: The authors successfully fitted large-diameter (12 mm) tricurve rigid gas-permeable contact lenses for 90 (47%) of 190 penetrating keratoplasty patients with good tolerance. There were nine dropouts, and 91 eyes were corrected in another way. Fitting contact lenses after grafting usually started after 8.5 months (range, 1-60 months). The average tolerance was 9.2 hours a day (range, 2-12 hours), and best-corrected visual acuity was 20/25 (range, 20/16-20/200). The average follow-up was at least half a year. The average age of the patient at the first lens fitting was 36.2 years (range, 14-75 years). There was no increased risk in graft rejection. CONCLUSIONS: Twelve-millimeter rigid gas-permeable contact lens wear was successful in 47% of patients who underwent penetrating keratoplasty for keratoconus. It does not interfere with the use of chronic postoperative topical medication, nor does it increase the risk of corneal graft rejection. It is necessary to recommend likely use of contact lenses to patients who have undergone grafting surgery.

Adolescent↗
PubMed2006

Biomechanically coupled curvature transfer in normal and keratoconus corneal collagen.

PURPOSE: To examine the hypotheses that a "pushed" biomechanically coupled intrafibrillar transfer of curvature may be involved in corneal warpage (pseudo cone) development, which is observed with superior cornea-bearing rigid contact lens fittings, and that a "pulled" biomechanically coupled intrafibrillar transfer of curvature may be involved in keratoconus cone development. METHODS: The mechanical properties of corneal stromal fibrils have been reviewed to examine the histologic basis for fibril inextensibility and the associated potential for them to demonstrate biomechanical coupling. DISCUSSION: The hypothesis that apical clearance rigid contact lenses may promote pushed biomechanical responses that aid cone development in some normal or keratoconic corneas is examined. CONCLUSIONS: Stromal fibrils that run limbus to limbus and have circumferential stability at the limbus, appear to be relatively inextensible: a finding that is consistent with the need for stable refraction. The property of inextensibility could also support intrafibrillar biomechanically coupled curvature transfer. For example, in some normal corneas, definite apical clearance fittings may be associated with biomechanically coupled push forces generated by midperipheral bearing that squeeze the central cornea to greater curvature. A disease-related biomechanically coupled pull mechanism for cone formation may be accelerated by an apical clearance fitting push mechanism, with additional synergy generated by subatmospheric pressure in the postlens tear pool. These fitting-related mechanisms appear likely to increase with the degree of apical clearance. Cone formation in keratoconus and models of external forces acting on the cornea (tonometry and contact lens-related) are mathematically analyzed for an idealized one-dimensional elastic model of a corneal stromal fibril. The classic theory of "elastic rods" is adopted, and despite the nonlinear nature of the differential equations involved, a method of dealing with biomechanically coupled curvature transfer in an "exact" manner is described and used to model the related clinical phenomena.

Animals↗
PubMedDate not supplied

Development of implantable right ventricular assist device.

Implantable ventricular assist devices (VADs) are indicated for long waiting periods before transplantation and also as a destination therapy. Meanwhile, right ventricular failure (RVF) is one of the four major complications observed in patients after left VAD (LVAD) implantation, with an incidence of approximately 20%. Preoperative prediction of the complication remains difficult, and the mortality is very high. To date, no implantable right VAD (RVAD) is available for the clinical situation. The possibility of realizing an implantable RVAD with Gyro centrifugal pump (PI-710 pump) was investigated. Eleven chronic animal experiments with LVAD and RVAD implantation were performed. Right heart bypass was established between right outflow and pulmonary trunk, and the pump was implanted in the preperitoneal space. The anatomic fit was good. The mean term of the experiments was 59 days, with excellent pump performance. Stable pulmonary hemodynamics and respiratory function were maintained during all of the experimental terms. No specific abnormal histologic findings of the lung were confirmed; however, tunica media hypertrophy was recognized in some cases. The PI-710 pump is feasible as a clinically implantable RVAD, but further study of histologic and pulmonary vascular changes after RVAD implantation is needed.

Animals↗
PubMed2001

NAL-NL1 procedure for fitting nonlinear hearing aids: characteristics and comparisons with other procedures.

A new procedure for fitting nonlinear hearing aids (National Acoustic Laboratories' nonlinear fitting procedure, version 1 [NAL-NL1]) is described. The rationale is to maximize speech intelligibility while constraining loudness to be normal or less. Speech intelligibility is predicted by the Speech Intelligibility Index (SII), which has been modified to account for the reduction in performance associated with increasing degrees of hearing loss, especially at high frequencies. Prescriptions are compared for the NAL-NL1, desired sensation level [input/output], FIG6, and a threshold version of the Independent Hearing Aid Fitting Forum procedures. For an average speech input level, the NAL-NL1 prescriptions are very similar to those of the well-established NAL-Revised, Profound procedure. Compared with the other procedures, NAL-NL1 prescribes less low-frequency gain for flat and upward sloping audiograms. It prescribes less high-frequency gain for steeply sloping high-frequency hearing losses. NAL-NL1 tends to prescribe less compression than the other procedures. All procedures differ considerably from one another for some audiograms.

Acoustic Stimulation↗
PubMed1996

On the influence of superstructure connection on implant preload: a methodological and clinical study.

In a combined in vitro and in vivo study strain gauges were used to register the deformation in two terminal implant abutment cylinders, when connecting three different prosthetic appliances. The prosthetic constructions were placed on the abutments and fastened in vitro and in vivo by using different torque sequences. Furthermore, in the in vitro situation the three medial abutments were replaced by abutments which were 100 microns shorter. The results show that even if the prosthetic constructions were judged to have a good clinical fit, relatively large External Preloads were registered both in vitro and in vivo. No significant differences in axial force or in bending movement were found between the torque sequences in vivo. There were, however, significant differences in axial force as well as in bending moment in the in vitro experiment. When the shorter medial abutments were used in vitro, a change in the axial force of approximately 200 N was registered. The results confirm that the methodological approach used in this study is valid when evaluating preloads.

Analysis of Variance↗
PubMed1996

Reliability and stability of various hearing-aid outcome measures in a group of elderly hearing-aid wearers.

Twenty elderly persons with hearing impairment were fit with binaural in-the-ear hearing aids and followed for a 6-month period post-fit. Several hearing-aid outcome measures were obtained at 0, 7, 15, 30, 60, 90, and 180 days post-fit. Outcome measures included (a) objective measures of benefit obtained with nonsense-syllable materials in quiet (CUNY Nonsense Syllable Test, NST) and sentences in multitalker babble (Hearing in Noise Test, HINT); (b) two subjective measures of benefit, one derived from pre-fit/post-fit comparisons on a general scale of hearing handicap (Hearing Handicap Inventory for the Elderly, HHIE) and the other based on a subjective scale of post-fit hearing-aid benefit (Hearing Aid Performance Inventory, HAPI); (c) a questionnaire on hearing-aid satisfaction; (d) an objective measure of hearing-aid use; and (e) a subjective measure of hearing-aid use. Reliability and stability of each measure were examined through repeated-measures analyses of variance, a series of test-retest correlations, and, where possible, scatterplots of the scores against their corresponding 95% critical differences. Many of the measures were found to be both reliable and stable indicators of hearing-aid outcome.

Aged↗
PubMed1994

Reconstructive amputation after grade IIIC open tibial fracture. One method of preserving residual limb length.

A high percentage of patients with grade IIIC open tibial fractures eventually undergo amputation. Maintaining an adequate residual limb length is advantageous with regard to biomechanics, energy expenditure, and prosthetic fitting. This case report presents new considerations for maintaining residual limb length in the presence of comminuted proximal tibial fractures. These considerations include (a) using an autogenous fibular strut graft for stabilizing the reconstructed residual limb and (b) determining the level of amputation based on soft-tissue integrity rather than on fracture level. We present one technique for preserving an adequate residual limb length in the face of significant proximal tibia comminution.

Accidents, Traffic↗
PubMed1993

Accuracy of fit of cobalt-chromium removable partial denture frameworks on master casts.

Fifty-six cobalt-chromium removable partial denture frameworks made to the same design were found to fit their master casts poorly. Spaces were significantly greater between palatal aspects of abutment teeth and palatal reciprocal arms, and between buccal aspects of occlusal rests and rest seats. Excessive contraction towards the centre of the palate was found. Expansion of the refractory investment may not have compensated adequately for solidification and cooling contraction of the cobalt-chromium alloy. Although dimensional changes in investment and casting are by volume, no evidence of anisotropic expansion of castings in a vertical direction was found.

Chromium Alloys↗
PubMed2005

[Gas permeable scleral lenses as a conservative treatment option for extreme corneal ectasias and severe dry eye].

PURPOSE: Due to their exclusive scleral contact zone, non-ventilated gas permeable scleral contact lenses can be used to correct extreme keratectasia, even if corneal fitted contact lenses failed previously. As the gap between the scleral lens and the cornea is filled with fluid substitutes, they also can be used for patients with severe aqueous-deficient dry eyes. PATIENTS, MATERIAL AND METHOD: Scleral lens fitting was attempted in 13 eyes (9 patients, group I) of patients with extreme corneal ectasia and 9 eyes (5 patients, group II) with severe ocular surface disease. Best corrected visual acuity, keratometry, Schirmer's test, foreign body sensation, and total daily lens wearing time were recorded prior to and after scleral lens fitting. RESULTS: Scleral lenses were successfully fitted and used on a long-term basis in 6 of 13 eyes (4 patients) of group I and 4 of 9 eyes of group II. In 9 eyes visual acuity increased by at least 2 lines, but long-term lens wear was not possible due to severe foreign body sensation or fornix shortening. CONCLUSIONS: Modern gas permeable scleral lenses can successfully be used for nonsurgical rehabilitation of severe corneal ectasia and dry eyes.

Adult↗
PubMed2001

The preferred number of channels (one, two, or four) in NAL-NL1 prescribed wide dynamic range compression (WDRC) devices.

OBJECTIVE: The recently introduced NAL-NL1 rationale for fitting WDRC devices prescribes a relatively high compression threshold and prescribes compression ratios lower than those prescribed by loudness normalization rationales. The aim of this study was to investigate whether the compression characteristic prescribed by NAL-NL1 is most effective in a single-channel scheme or in a multi-channel scheme. DESIGN: Twenty-four subjects with flat or steeply sloping hearing loss participated in the study. One, two, and four channels were implemented digitally in the laboratory and evaluated on the basis of a paired-comparison test and a speech recognition test. The test stimuli consisted of speech and noise presented at average input levels, and speech and noise alternating every 3 sec among different input levels. The single-channel and 2-channel NAL-NL1 prescriptions were also evaluated in individually selected everyday situations in the field using a digital 2-memory device. RESULTS: The three compression schemes produced no significant difference in speech recognition scores. Most subjects showed no preference for either scheme in the paired-comparison test. Those who did mainly selected the single-channel scheme. These preferences can be explained on the basis on audibility and quality. In the field all subjects with a steeply sloping loss, but one, preferred the 2-channel scheme. Among the subjects with a flat loss more preferred the single-channel scheme than preferred the 2-channel scheme. Statistical analyses showed that those who preferred the 2-channel scheme were fitted with significantly greater differences in the compression ratio in the high frequencies, and those who preferred the single-channel scheme were fitted with significantly greater differences in the high-frequency gain for a 65 dB input. CONCLUSIONS: Multi-channel compression prescribed according to NAL-NL1 in up to four channels showed no adverse effects on speech recognition relative to a single-channel scheme. The paired-comparison test showed a small, but explainable preference for the single-channel scheme. The field test revealed a preference for the 2-channel scheme by subjects with steeply sloping loss. When using the NAL-NL1 rationale it is recommended to use at

Acoustic Stimulation↗
PubMed2005

Parental distress: the initial phase of hearing aid and cochlear implant fitting.

The results of previous cross-section studies suggest that childhood hearing impairment may lead to parental psychosocial stress. The present study investigated whether modifications in parental psychic state can be ascertained in connection with the child's treatment events and the child's hearing and speech status, in a prospective study design. Data were available on 116 fathers and mothers regarding the pre-cochlear implant examination or hearing aid fitting of their child. In the course of the child's treatment, parental quality of life improved from a low to a normal level. Among children who were at the stage of pre-examination for a cochlear implant, better hearing and speech capacity was linked to more severe impairment of the parental state. It is emphasized that the parents whose children showed comparatively good language development at the time of pre-examination for a cochlear implant were especially subjected to stress.

Child, Preschool↗
PubMed1995

Efficient soldering index materials for fixed partial dentures and implant substructures.

Multiple-unit fixed partial dentures routinely require an intraoral index to ensure accurate fit. One of the most commonly used materials is Duralay acrylic resin, which has yielded satisfactory clinical results, but one disadvantage has been a prolonged setting time. This study compared the setting times of two autopolymerizing resins, Duralay and G. C. Pattern resin. The dimensional accuracy of these materials was also compared with one light-cured resin, G.C. Unifast light-cure resin. All three materials were suitable to relate castings with clinically acceptable outcomes, and chairside time could be saved with the use of recently introduced indexing materials.

Dental Abutments↗
PubMed2004

Comparison of three procedures for initial fitting of compression hearing aids. III. Inexperienced versus experienced users.

We assessed whether gain requirements differ for experienced users and new users when fitted with multi-band compression hearing aids Three procedures for initial fitting were used: the Cambridge method for loudness equalization (CAMEQ), the Cambridge method for loudness restoration (CAMREST), and the desired sensation level input/output (DSL[i/o]) method. Twenty experienced hearing aid users and 20 new users with mild-to-severe sensorineural loss were fitted with Danalogic 163D digital hearing aids, using each procedure in turn in a counter-balanced order. The new users were given a pre-fitting with slightly reduced gains prior to the 'formal' fitting. Immediately after formal fitting with a given procedure, and 1 week after fitting, the gains were adjusted by the minimum amount necessary to achieve acceptable fittings. The amount of adjustment required provided the main measure of the adequacy of the initial fitting. On average, new users required decreases in gain for all procedures, the decreases being larger for DSL[i/o] than for CAMEQ or CAMREST. For experienced users, gain adjustments were small for CAMEQ and CAMREST, but were larger and mostly negative for DSL[i/o]. After these gain adjustments, users wore the aids for at least 3 weeks before filling out the Abbreviated Profile of Hearing Aid Benefit (APHAB) questionnaire and taking part in laboratory measurements of the speech reception threshold (SRT) for sentences in quiet and in steady and fluctuating background noise at levels of 60 and 75 dBSPL. The scores on the APHAB test and the SRTs did not differ significantly for the three procedures. We conclude that the CAMEQ and CAMREST procedures provide more appropriate initial fittings than DSL[i/o]. For inexperienced users, gains typically need to be reduced by about 3dB relative to those prescribed by CAMEQ or CAMREST, although the amount of reduction may depend on hearing loss. An analysis of gain adjustments as a function of order of testing provided some evidence for increased tolerance to high-frequency amplification with increasing experience during the 4-month course of the trial, but this effect did not differ for the experienced and new users.

Acoustic Stimulation↗