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Biomedical subjects

A D Walmsley

Publications and source records attributed to A D Walmsley.

At least 37 records · Page 2Linked to original sources
PubMed2003

The use of the Internet within a dental school.

The Internet is an increasingly popular medium for delivering educational material. The aim of this study was to determine the attitudes of students and their clinical teachers to the use of the Internet within a dental school in the UK. Questionnaires were distributed to undergraduate dental students in the three clinical years and to all their clinical academic teachers. All students and staff have access to computers and Internet at the university. The majority (72%) of students have access to a computer and 53% also have access to the Internet at home. Of the academic staff, 91% have a computer and 68% have access to the Internet at home. The reasons for use of the Internet differed between staff and students. Whilst equal proportions of students used the Internet for dentistry (38%) and for pleasure (35%), a higher proportion of staff used the Internet more for dentistry (36%) than for pleasure (14%). Students highlighted cost and time as barriers to Internet use, whereas staff lacked confidence in their ability to use the Internet. Less than half (44%) of the students are confident in the accuracy of information from the Internet compared to almost two-thirds (64%) of staff. This study revealed differences in the attitudes of staff and students to the use of Internet as a resource for dentistry. Students are positive to the suggestion that lectures should be presented on the web. Most students (74%) did not see that this would influence attendance at lectures whilst 91% of staff stated that it would decrease lecture attendance. In conclusion, this study revealed differences in the attitudes of staff and students to the use of Internet as a resource for dentistry.

Attitude of Health Personnel↗
PubMed2003

Dental undergraduate expectations and opinions of Web-based courseware to supplement traditional teaching methods.

The rapid growth of Internet for the delivery of information has enabled teaching materials to be placed on websites allowing student access to course material. It is the aim of this paper to evaluate a cohort of dental undergraduate students who have used Web-based courseware in prosthetic dentistry for a semester. A questionnaire was distributed to clinical undergraduate students prior to the use of the prosthetics course to determine their experience of using the World Wide Web (WWW) and their expectations of an online course. A second questionnaire was distributed at the end of 6 months which asked about their usage and opinions of the prosthetics Web-based courseware. The main concerns raised at the beginning of the course were related to computer access, the ability to use computers, the time involved and their conception that the e-course would be an additional burden. The main potential benefits were perceived to be convenience, availability of information and the ability to reinforce or catch up on aspects of the module they did not understand or had missed. Feedback at the end of the year showed that most students had accessed the Web-based courseware site at least once a month and, generally, their comments were favourable, dispelling some of the initial perceived fears. They felt that the website was a quick and convenient way to access information and was a good additional resource. Access to the site and printing information were the main problems raised by the students who had to use a shared cluster. In conclusion, Web-based courseware was felt to be a useful additional resource for students. However, this research showed that sufficient computers and printers must be available for such a resource to become an integrated part of the dental course.

Adult↗
PubMed2002

Vibration characteristics of ultrasonic scalers assessed with scanning laser vibrometry.

OBJECTIVES: Scanning laser vibrometry is a non-invasive method of accurately measuring the vibratory characteristics of oscillating objects. The aim of this study was to observe, using a scanning laser vibrometer (SLV), the vibration patterns of dental ultrasonic scaler tips and to assess the effects of water flow rate and power setting on these patterns whilst operating the tips in an unloaded environment. METHODS: A 30kHz ultrasonic scaler (TFI-10, Dentsply) was fixed in position and a laser beam from the SLV was focused onto the tip. The laser, guided by a virtual measurement grid, was scanned over the oscillating tip surface. Scans were taken with the laser beam perpendicular to the long axis of the front face of the tip. RESULTS: Oscillation frequencies and the displacement amplitude at the unconstrained end of the tip were measured for various power/water settings. Vibration nodal positions were recorded for the various settings and were found to occur approximately 4mm from the free end of the tip. At low and medium power settings, tip displacement amplitude was reduced by increased water flow. At high power settings, combined with a high flow rate, the water leaves the body of the instrument as a jet. This left the tip relatively unconstrained, allowing it to oscillate at increased displacement amplitudes. CONCLUSIONS: This study shows that the SLV is able to accurately characterise the movement of oscillating ultrasonic scaler tips. The tips are affected by power setting and water flow rates.

Analysis of Variance↗
PubMed2002

Assessment of the ultrasonic dental scaler insert.

The ultrasonic dental scaler is an invaluable tool in the fight against dental calculus and periodontal disease. The purpose of this study was to assess the natural frequency of the straight internal ultrasonic scaler insert 30K FSI-SLI-10S (Dentsply International, York, USA) and to measure the displacement observed at the tip when operated under different generator settings. Two approaches were used: finite element analysis and scanning laser vibrometry. The Finite Element Analysis method was employed to calculate the expected modes of vibration of the insert. Scanning laser vibrometry was used to measure displacements of the tip during operation. It was found the insert had two modes of vibration around the operating frequency of 30 kHz; these modes were first order bending in two orthogonal planes.

Dental Scaling↗
PubMed2002

Evaluation of smear layer removal by EDTAC and sodium hypochlorite with ultrasonic agitation.

AIM: To evaluate smear layer removal by different irrigating solutions under ultrasonic agitation. METHODOLOGY: Twenty recently extracted mandibular incisors with a single root canal were divided into four equal groups. Three groups were instrumented using the modified double-flared technique, the fourth remained unprepared. Each group was irrigated with either distilled water, 1.0% sodium hypochlorite alone or associated with 15% EDTAC between each file size. The final group was not instrumented but irrigated with 1.0% sodium hypochlorite and 15% EDTAC. A size 15 file energised by ultrasound was used with small amplitude filing movements against the canal walls in all groups. The teeth were split longitudinally and the roots measured to provide three sections of the same size (cervical, middle and apical). Samples were examined under the scanning electron microscope and assessed for the amount of smear layer by three independent and calibrated examiners. The scoring system ranged from 1 (no smear layer) to 4 (all areas covered by smear layer). Due to the non-parametric nature of the data, Friedman's test was used for statistical analysis. RESULTS: Canal walls were covered with smear layer in the group irrigated with 1% sodium hypochlorite alone and the group irrigated with distilled water. Canals irrigated with 1.0% sodium hypochlorite associated with 15% EDTAC had less smear layer throughout the canal (P < 0.001). There were no statistical differences for the amount of smear layer found on the cervical, middle and apical thirds when each group was analysed separately. CONCLUSIONS: Under ultrasonic agitation, sodium hypochlorite associated with EDTAC removed the smear layer from root canal walls, whereas irrigation with distilled water or 1.0% sodium hypochlorite alone did not remove smear layer.

Dental Pulp Cavity↗
PubMed2001

Scope of the OSCE.

Explore the source record for details and available documents.

Clinical Competence↗
PubMed2001

Plaque removal characteristics of electric toothbrushes using an in vitro plaque model.

BACKGROUND/AIM: The purpose of the study was to investigate and quantify the efficacy of plaque removal by commercially available electric toothbrushes using an in vitro system based on artificial plaque grown on glass slides. MATERIAL AND METHODS: Artificial plaque based on Streptococcus sanguis and Streptococcus mutans was cultured in a series of phosphate buffer solution, sucrose solution and brain heart infusion on sterile glass slides, for a period of 5 weeks. 7 different electric toothbrushes of current designs were operated in contact with the glass slides under loads of 1 or 2N for 10 s after which image analysis of the brushed slides was undertaken to calculate the absolute and relative areas of removal. RESULTS: The electric toothbrushes showed a larger area of plaque removal as loading force increased from 1 to 2N. The area of biofilm removed also depended on the head design and ranged from 258 mm(2) (1N, Interplak) and 314 mm(2) (2N, Interplak), to 30 mm(2) (1N, Braun 3D), and 148 mm(2) (2N, Blend-a-Dent). The area of biofilm removal was significantly different among all electric toothbrushes at p<0.01 (ANOVA). All electric toothbrushes removed more biofilm than the actual contacting tufted area of the head. CONCLUSION: The artificial plaque model system under different loading conditions showed differences in the absolute area of removal per electric toothbrush and also differences in the relative removal per unit contact bristle area. These differences on operating variables should be considered when evaluating new electric toothbrushes.

Algorithms↗
PubMed2001

Determination of acetonitrile and ethanol in water by guided microwave spectroscopy with multivariate calibration.

The feasibility of using guided microwave spectroscopy (GMS) utilizing the frequency range 0.25-3.20 GHz, was combined with multivariate calibration for the determination of acetonitrile or ethanol concentration in water. A wide range of different concentrations was used (up to 30% v/v). Partial least squares (PLS) and weighted ridge regression (WRR) was applied to generate a model for prediction, based upon the microwave spectra. A high level of collinearity was observed in both of the sample data sets and this was reduced by background subtraction. The prediction ability for the two types of regression models were found to be comparable with the percentage error of prediction (PEP) being approximately 2.5% for the acetonitrile samples and 1.1% for ethanol samples.

Journal Article↗
PubMed2001

Magnets in prosthetic dentistry.

Magnetic retention is a popular method of attaching removable prostheses to either retained roots or osseointegrated implants. This review chronicles the development of magnets in dentistry and summarizes future research in their use. The literature was researched by using the Science Citation Index and Compendex Web from 1981 to 2000. Articles published before 1981 were hand researched from citations in other publications. Articles that discussed the use of magnets in relation to prosthetic dentistry were selected.

Dental Prosthesis Retention↗
PubMed2000

Investigations into the use of an ultrasonic chisel to cut bone. Part 1: Forces applied by clinicians.

OBJECTIVES: To measure in vitro the direction and force of applied loads applied by clinicians when using both a conventional slow surgical handpiece (CH) and an ultrasonic chisel (USC) for cutting bone. STUDY DESIGN: Five clinicians were asked to cut bovine bone using either an USC or a CH. The bone was placed on a force measurement system that could measure both longitudinal and downward loads. The rate of cut was calculated over a fixed time-period and the depth of cut measured using a penetratometer. RESULTS: The magnitude of the longitudinal forces generated varied between 1.48 and 3.22 N (USC) and 0.04 and 4.56 N (CH). The CH had a pulling force directed towards the operator. Both instruments produced a similar range of downward forces although there was intra- and inter-operator variability. The rate of cut varied in a similar manner, however, the CH produced a significantly greater depth of cut (p < 0.05). CONCLUSIONS: The force measurement system demonstrated differences in the way clinicians used the USC and CH instruments to cut bone. Of the two cutting methods investigated, the rotary bur is more efficient than the ultrasonic chisel. An ultrasonic chisel does cut bone in a different manner from a conventional bur and clinicians may require training before using it clinically.

Analysis of Variance↗
PubMed2000

Investigations into the use of an ultrasonic chisel to cut bone. Part 2: Cutting ability.

OBJECTIVES: Ultrasound may offer a possible alternative to rotary instruments for removing bone. This study was undertaken to analyse in vitro the various factors that influence the cutting of bone by an ultrasonic chisel. STUDY DESIGN: A block of bovine femur was moved in a longitudinal direction under a stationary ultrasonic chisel. The force and depth of the cut was recorded for cutting rates of 28-112 mm/min and with increasing rake angles of 0 to +20 degrees. The pressure exerted by the chisel was recorded for different cutting rates. RESULTS: When the cutting rate increases there is a corresponding increase in the downward force which is followed by a decrease in the force at rates greater than 56 mm/min. The depth of the cut increases up to a rate of 56 mm/min after which it decreases. Both the longitudinal and downward forces do not change when the rake angle changes from 0 to +10 degrees. The downward force decreases when the rake angle increases from +10 to +20 degrees. CONCLUSIONS: The bone is cut slowly with the ultrasonic chisel, but this would assist in precision. Where such an instrument is used for cutting bone the clinicians should be aware that both low forces and cutting rates are required, and the instrument should be held at a low rake angle.

Animals↗
PubMed2000

Development and evaluation of a stand-alone web-based CAL program. A case study.

The use of web browser technology allows the construction of computer-aided learning programs which will have a familiar interface to dentists. This paper reports on the evaluation of a web-based CAL program which covered the topic of tooth wear with an emphasis on the rôle of erosion in its aetiology. Evaluation of the software was made by 50 dentists contacted by an electronic mailing list. They completed a questionnaire which evaluated aspects of the functionality of the program educational objectives. The average age of the dentists was 39 years (range 24-70) and 82% were male. The average time of use was 1 h 10 min (range 15 min to 3 h). A significant change in their knowledge of tooth wear before and after using the program was recorded. Both the use of patient cases and leaflets scored highly with other aspects such as treatment planning and patient advice receiving high marks. All dentists commented that they had gained greater knowledge with particular reference to treatment and advice of tooth wear problems. 34 dentists (68%) found the web interface easy to use. Negative comments were mainly attributed to the quality of the pictures (4/50) which were corrected in the final release version. Respondents were asked to compare the program to other educational media on the same subject. 80% rated this CAL program as better than video, and 14% claimed it was as good as video. 84% rated it better than books, and 14% said it was as good as books. 98% preferred it to audio tapes and 86% preferred it to journals. The average amount that they would pay for a CAL package such as "tooth wear" would be 42 ECU. It is concluded that web browser software is a suitable medium for the use of a CAL program and this is reflected in its ease of use by dentists.

Adult↗
PubMed2000

Walmsley's Web watch.

The ADEE site serves as a portal to other educational sites around the world. The address can be book-marked and used as a focus to explore and use the Web in a constructive way without becoming overwhelmed with the large amount of information that is present. There are, of course, many other sites that act as a resource and contain links to other web pages. This site is simple to use, contains links to web pages that are of high quality and will prove useful to people wishing to update their current knowledge.

Dentistry↗
PubMed2000

Walmsley's web watch.

Explore the source record for details and available documents.

Education, Dental, Continuing↗
PubMed1999

Ultrasound-enhanced diffusion into coupling gel during phonophoresis of 5-fluorouracil.

PURPOSE: To investigate the competitive transport across skin and back-diffusion of 5-fluorouracil into coupling gel under the influence of ultrasound, heat-alone and Azone enhancement. METHODS: The ultrasound effect on 5-fluorouracil penetration through whole rat skin was investigated in modified diffusion cells using a commercial ultrasound generator which was calibrated with a bilaminar membrane hydrophone. RESULTS: Ultrasonic dosimetry measurements demonstrated that the skin membrane was subjected to a complex and unpredictable standing wave field which induced physiologically acceptable heating of the tissue. Surprisingly, ultrasonication produced a decrease in percutaneous drug penetration. Quantification studies indicated that this effect was due to the diffusive loss of the hydrophilic substance 5-fluorouracil from the skin surface into the overlying volume of coupling gel. This phenomenon could be duplicated by the application of conductive heating, indicating that the thermal effects of ultrasound were probably responsible for accelerated 5-fluorouracil diffusion through the gel. CONCLUSION: This study acutely demonstrates how formulation design of the donor vehicle/coupling gel may radically affect therapeutic efficacy in phonophoretic systems.

Animals↗
PubMed1999

Acoustic microstreaming: detection and measurement around ultrasonic scalers.

BACKGROUND: Acoustic microstreaming (AMS) may be useful to the clinician when using the ultrasonic scaler to remove particulate matter from the teeth. The aim of this study was to detect and measure the effects of AMS produced by ultrasonic scalers. METHODS: For the study, an ultrasonic generator was selected with 4 differently shaped scaling tip inserts (TFI-3, TFI-9, TFI-1, and P-12). A plaque substitute (0.2 mm thick soft cream cheese) was coated onto a microscope slide and immersed in water. The ultrasonic scaler tip was placed in the water and orientated either perpendicular or parallel to the slide. The instrument was operated both contacting the slide under a load of 0.3 N and non-contacting at various distances from the slide surface. This was repeated with the tip parallel to the slide. The area of medium removed was quantified by digital image analysis. RESULTS: It was found that AMS removed the plaque substitute from around the tip. The TFI-9 insert significantly removed more material with increasing displacement amplitude (P <0.05). Significantly larger areas of plaque substitute were removed when the tips of the TFI-3, TFI-9, and P-12 inserts were orientated perpendicularly to the slide compared to the parallel orientation (P <0.05). Of the 4 inserts used, the TFI-9 insert removed the most material while the straight tip produced no apparent removal. Removal by AMS required the presence of a water medium and such forces were found to decrease with distance from the scaling tip. No plaque substitute removal was seen at a distance of 7 mm for the TFI-9 insert at 37.5 microm displacement with the tip orientation parallel to the slide. CONCLUSIONS: It is concluded that AMS occurs around ultrasonic scalers and this depends on the displacement amplitude, tip orientation, and presence of a water medium. AMS may play a role in disruption of subgingival biofilms associated with periodontal disease.

Acoustics↗