PubMed Health⌕ Search

Biomedical subjects

G M Carter

Publications and source records attributed to G M Carter.

At least 19 recordsLinked to original sources
PubMed2000

The Postgraduate Diploma in Clinical Dental Technology.

The Dental Act 1988 included requirements for the registration of clinical dental technicians, a new category of dental health worker. Despite the Act containing provision for a course of training in clinical dental technology, 11 years elapsed before the first candidates would graduate in this discipline. This paper describes the development and implementation of the new Postgraduate Diploma in Clinical Dental Technology, PGDipCDTech(Otago). Diplomates of the inaugural course in 1999 were the first students, other than students of dentistry, to obtain a clinical qualification from the School of Dentistry. Overall the course was very successful, but the provisions of the Dental Act inhibit flexible approaches to the teaching of clinical dental technology.

Credentialing↗
PubMed2000

A clinically detailed risk information system for cost.

The authors discuss a system that describes the resources needed to treat different subgroups of the population under age 65, based on burden of disease. It is based on 173 conditions, each with up to 3 severity levels, and contains models that combine prospective diagnoses with retrospectively determined elements. We used data from four different payers and standardized the cost of most services. Analyses showed that the models are replicable, are reasonably accurate, explain costs across payers, and reduce rewards for biased selection. A prospective model with additional payments for birth episodes and for serious problems in newborns would be an effective risk adjuster for Medicaid programs.

Adolescent↗
PubMed1999

novel Award First Prize Paper. Orthotic management of plantar pressure and pain in rheumatoid arthritis.

OBJECTIVE: To investigate the effectiveness of foot orthoses in the management of plantar pressure and pain in subjects with rheumatoid arthritis. DESIGN: A repeated measures study in which the independent variable was orthosis design. Dependent variables, including pressure, gait and pain parameters, were examined using analysis of variance and correlation statistics. BACKGROUND: The aim of orthotic management of the rheumatoid foot is to relieve metatarsalgia through the reduction of metatarsal head pressure. Few studies have investigated the relative effectiveness of different orthosis designs. To date, no studies have examined the relationship between plantar pressure and second metatarsal head pain in rheumatoid arthritis subjects. METHODS: Twelve rheumatoid arthritis subjects with foot involvement and second metatarsal head pain were tested. Four styles of foot orthosis (prefabricated, standard custom moulded, custom with metatarsal bar, custom with metatarsal dome) were compared to a shoe only control. An EMED Pedar system was used to measure plantar pressure during repeated trials of comfortable cadence walking and quiet standing. Reports of subjective pain were recorded for each orthosis as were orthosis preferences. RESULTS: All orthoses significantly reduced pressure beneath the first and second metatarsal heads compared to the shoes only control. The custom moulded orthosis with metatarsal dome was the most effective orthosis for reducing subjective ratings of pain. A significant correlation (r=0.562) was found between ratings of pain and average pressure beneath the second metatarsal head. CONCLUSIONS: Results from this study suggest that average pressure measurement may be a useful indicator in the management of metatarsalgia in RA. Further study is required to improve understanding of the relationship between rheumatoid foot mechanics and pain. RELEVANCE: Appropriate foot orthosis design can substantially improve comfort in RA patients with symptomatic feet. A custom moulded foot orthosis incorporating a metatarsal dome was the most effective design for subjects with painful second metatarsal heads. Foot pressure measurement technology can be a useful adjunct to research and clinical management of the painful rheumatoid foot.

Aged↗
PubMed1998

Where is the financial safety net for managed care physicians?

OBJECTIVE: Empiric research on mechanisms by which managed care physicians attempt to mitigate financial risk is lacking. We assumed the perspective of a managed care plan in investigating the relationship between risk sharing and the match between a physician's capitation payments and costs of care. DESIGN: The study design was a family of payment simulations using 2 years of managed care claims data. METHODS: Claims from a cohort of 82,525 managed care patients were used, with year 1 data determining a capitation rate for year 2 primary care services. The net provider payment in year 2 was examined under scenarios that might modify financial outcomes, including stop-loss insurance, age- and gender-adjustment of capitation, and risk pooling within independent practice associations. RESULTS: The size of a provider's patient panel was positively correlated with net per capita payment (r = 0.22; P < 0.0001 without risk modification strategies). The variance of the ratio of net to total revenue was utilized as a proxy for the degree of risk assumed in caring for a panel of capitated enrollees. Risk modification strategies reduced this variance measure, with risk pooling producing the largest effect, especially for providers of panels of fewer than 135 patients. In contrast, age- and gender-adjustment of capitation payments had little effect on reimbursement outcomes. CONCLUSIONS: Short of increasing the pool of capitated patients, risk modification strategies appear limited in their ability to produce more equitable reimbursement to providers with small patient panels. With many providers assuming substantial risk in pursuing managed care contracts, these dynamics may favor organizational forms of medical practice that facilitate large patient panels within a single plan.

Capitation Fee↗
PubMed1997

Variations in cataract extraction rates in Medicare prepaid and fee-for-service settings.

OBJECTIVE: To compare rates of cataract extraction in 2 prepaid health settings and in traditional fee-for-service (FFS) settings. DESIGN: A cross-sectional analysis using 1993 health maintenance organization (HMO) Medicare claims and encounter files, the Health Care Financing Administration (HCFA) 5% Medicare Part B provider/supplier file, and the HCFA October 1992 100% Medicare population file. SETTING: Southern California Medicare FFS settings and the staff-model and independent practice association (IPA) plans of a large California HMO. PATIENTS: 1993 Medicare beneficiaries aged 65 years and older. The study included 43387 staff-model HMO enrollees, 19050 IPA enrollees, and 47 150 FFS beneficiaries (a 5% sample of all Southern California FFS beneficiaries). MAIN OUTCOME MEASURE: Age and risk-factor adjusted rates of cataract extraction per 1000 beneficiary-years. RESULTS: After controlling for age, sex, and diabetes mellitus status, FFS beneficiaries were twice as likely to undergo cataract extraction as were prepaid beneficiaries (P<.01). Female FFS beneficiaries were nearly twice as likely to undergo the procedure as were male FFS beneficiaries (P<.001); there were no extraction rate differences by sex in the prepaid settings. CONCLUSION: Because of the potential implications for vision care in the elderly, the significantly different rates of cataract extraction in FFS and prepaid settings warrant further clinical investigation to determine whether there is overuse in FFS vs underuse in prepaid settings. Such investigations must assess the appropriateness of cataract surgery by evaluating its use relative to clinical need.

Age Distribution↗
PubMed1997

Factors influencing the retention of cemented implant-supported crowns.

This study is a retrospective analysis of the influence of cement, coping type, and fixture site on the cementation failure of 36 selected implant-supported single crowns placed between 1991 and 1995. Fisher's exact test and a log linear analysis were performed on the data. Crowns constructed with a milled-metal coping, cemented with a temporary cement, or placed in the maxillary premolar site were more likely to be associated with cement failure than those cemented with zinc phosphate, constructed with cast metal or ceramic copings, or placed in the anterior maxilla. We were unable to account for some variables-for example, bite force or oral habits. For this reason we consider that we would overstate the strength of this case analysis if we drew general conclusions from our results. However, we have altered our treatment protocol to reduce the initial cost and the maintenance associated with recementing implant-supported crowns, discontinuing the use of the milled-gold cylinder in view of the lack of any clear clinical advantage and the results of this study. In addition, and because only one internal gold screw in our series of patients has loosened, we now use a permanent cement.

Confidence Intervals↗
PubMed1996

Modified capitation and treatment incentives for end stage renal disease.

This study developed a modified capitation payment method for the Medicare end stage renal disease (ESRD) program designed to support appropriate treatment choices and protect health plans from undue financial risk. The payment method consists of risk-adjusted monthly capitated payments for individuals on dialysis or with functioning kidney grafts, lump sum event payments for expected incremental costs of kidney transplantations or graft failures, and outlier payments for expensive patients. The methodology explained 25 percent of variation in annual payments per patient. Risk adjustment captured substantial variations across patient groups. Outlier payments reduced health plan risk by up to 15 percent.

Capitation Fee↗
PubMed1995

A lifetime-based optical CO2 gas sensor with blue or red excitation and stokes or anti-stokes detection.

We describe the fabrication and characterization of an optical CO2 sensor based on the change in fluorescence lifetimes due to fluorescence resonance energy transfer from a pH-insensitive donor, sulforhodamine 101, to a pH-sensitive acceptor, either m-cresol purple or thymol blue, entrapped in an ethyl cellulose film. A phase transfer agent allows incorporation of the dyes and water into the film, while providing an initially basic environment for the acceptor. Diffusion of CO2 into the water entrapped in the film produced carbonic acid, causing a pH-dependent decrease in the spectral overlap of the acceptor absorbance with the donor emission, and decreased energy transfer, resulting in increased SR101 donor lifetimes. The lifetime changes were detected as a change in the phase of the emission, relative to the modulated excitation, and were insensitive to excitation intensities and emission signal levels. In addition to an externally modulated 442-nm light source, we excited the sensor with a directly modulated 635-nm laser diode and detected the anti-Stokes emission. The CO2 sensor is not fragile and can provide stable readings for weeks. The use of fluorescence resonance energy transfer, along with the simple entrainment procedure, allows facile change of the CO2 response range through change of the acceptor dye and the use of laser diode excitation sources.

Chromogenic Compounds↗
PubMed1995

Stress relaxation properties of human dentin.

OBJECTIVES: This study compared the stress relaxation properties of moist and air-dried human dentin to determine if air drying modifies this mechanical property. METHODS: Cylindrical dentin specimens, prepared from human canine and maxillary incisor teeth, were subjected to a controlled compressive stress applied at a constant strain rate to a predetermined maximum value, and the stress relaxation response recorded. Groups of moist and air-dried specimens were tested at both low and high stress. After a period of 1 wk, the incisor specimens were retested. RESULTS: The dentin exhibited a linear stress relaxation with the logarithm of time. Air-dried dentin consistently demonstrated a decreased stress relaxation. When subjected to a second high load, the air-dried dentin displayed significantly slower stress relaxation. Air-dried incisor dentin was found to be significantly stiffer than air-dried canine dentin. SIGNIFICANCE: These data suggest that the stress relaxation properties of human dentin are modified by air drying and by previous exposure to a constant compressive strain.

Biomechanical Phenomena↗
PubMed1995

Sensing oxygen through skin using a red diode laser and fluorescence lifetimes.

The most difficult impediments to transcutaneous optical sensing are the absorbance and scatter of light caused by skin and the lack of fluorescent sensing probes which can be excited at wavelengths over 600 nm. Furthermore, current optical sensing techniques rely on absorbance or fluorescence intensity measurements, both of which are sensitive to drifts in lamp intensity, changes in probe concentration and inner filter effects. We demonstrate oxygen sensing through a layer of skin by using red light which readily penetrates skin as diffusely scattered light. The oxygen sensitive osmium-ligand complex used in this study can be excited at 635-680 nm. In addition, we measure fluorescence lifetimes, which are inherently unaffected by factors that limit absorbance and fluorescence intensity measurements. By using phase fluorimetry and long lived fluorophores, we are able to demonstrate the potential for subdermal oxygen sensing with simple and inexpensive instrumentation. This work describes a paradigm for future non-invasive measurements of other analytes.

Biosensing Techniques↗
PubMed1995

Alterations to mandibular form following motor denervation of the masseter muscle. An experimental study in the rat.

The form of the mandible in young rats was studied following denervation of the masseter muscle. Wistar-derived male rats aged 27 d were randomly assigned either to experimental, sham-operated or control groups. The main trunk and initial branches of the masseteric nerve were resected on one side in each experimental animal. The nerve was exposed, but not resected, in the sham-operated group. No surgery was performed on the control group. All animals were killed at 69 d of age, examined and standardised contact radiographs taken of the cleaned and dried mandibles. Radiographic measurements describing the form and size of the mandibles were compared. On the operated side in the experimental animals the masseter muscle was smaller and the temporalis muscle larger as compared with the unoperated side. The angular process and the subcondylar incisure were also smaller and the coronoid process was positioned more rostrally. The most striking feature was that relatively little change accompanied denervation of masseter in the growing experimental rats. It is concluded that some of the changes previously attributed to muscle denervation may be due to other causes.

Analysis of Variance↗
PubMed1995

Six years' experience with Brånemark osseointegrated implants.

Over 6 years of the implant programme in the University of Otago School of Dentistry, the rate of use of osseointegrated implants to support or retain a dental prosthesis has increased. This increased use has been most marked in young adults who have required the restoration of a single space in the anterior maxillae. The treatment outcome is unequivocally positive, with an overall fixture retention rate of over 99 percent.

Adolescent↗
PubMed1994

Use of diagnosis-related groups by non-Medicare payers.

Medicare's prospective payment system (PPS) for hospital cases is based on diagnosis-related groups (DRGs). A wide variety of other third-party payers for hospital care have adapted elements of this system for their own use. The extent of DRG use varies considerably both by type of payer and by geographical area. Users include: 21 State Medicaid programs, 3 workers' compensation systems, the Civilian Health and Medical Program of the Uniformed Services (CHAMPUS), more than one-half of the Blue Cross and Blue Shield Association (BCBSA) member plans, several self-insured employers, and a few employer coalitions. We describe how each of these payers use DRGs. No single approach is dominant. Some payers negotiate specific prices for so many combinations of DRG and hospital that the paradigm that payment equals rate times weight does not apply. What has emerged appears to be a very flexible payment system in which the only constant is the use of DRGs as a measure of output.

Data Collection↗
PubMed1994

Implant-based treatment for the loss of a single tooth.

This article describes the authors' experience in the provision of single-tooth replacement by means of Brånemark implant treatments. Over a 5-year period, 45 treatments have been undertaken with a current fixture retention rate of 100 percent. Careful planning and attention to detail in surgical, prosthodontic, and technical aspects have resulted in an excellent functional and aesthetic treatment with high acceptance by patients.

Bicuspid↗
PubMed1994

Success and failure in partial edentulism treated with implant-supported bridges.

This report describes success and failure in the use of fixed bridges supported by Brånemark implants, placed in the mandible bilaterally in one patient and unilaterally in the other. The non-intrusive nature and excellent functional characteristics of such bridges make them an attractive alternative to a removable partial denture in making good the loss of posterior mandibular teeth. However, there are biomechanical principles which must be considered in the design of such appliances. In particular, designs which minimise bending moments should be chosen to avoid the type of failure described in one of our patients. Repeated loosening of screw components should be considered as a possible indicator of bending overload. Where space permits, this problem is most easily overcome by placing three implants in staggered formation.

Adult↗
PubMed1993

Fractures and dislocations of fingers and toes. Principles, tips and pitfalls.

If each injury is carefully assessed on its merits good outcomes will be achieved. If any kind of unusual situation is met advice should be sought early rather than late. Balancing competing concepts, especially with regard to mobilisation and immobilisation of the injured part, makes treatment of digital injuries a challenge to our ingenuity.

Finger Injuries↗