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Biomedical subjects

C W Barclay

Publications and source records attributed to C W Barclay.

12 recordsLinked to original sources
PubMed2006

Dental implantology education: a survey of opinion and experience of 106 general dental practitioners.

In the United Kingdom the National Health Service only provides dental implant treatment to patients who fulfil stringent clinical criteria outlined by the Royal College of Surgeons. Such treatment is normally in a hospital setting. The majority of dental implant work is otherwise carried out in the private sector. Concern about the quality of implant dentistry and training led the General Dental Council to convene a working group that set out to set training standards in implant dentistry for general dental practitioners (GDPs). The Faculty of General Dental Practitioners published this guidance in March 2006. This questionnaire based study set out to examine GDP attitudes to implant treatment and training and aims to contribute to the debate and review of appropriate training in dental implantology for GDPs.

Chi-Square Distribution↗
PubMed2006

Identification of dental implants through the use of Implant Recognition Software (IRS).

AIM: To develop computer software to allow general dental practitioners and others to identify unidentified implants in patients' mouths using a range of criteria. METHODS: Internet searches for implant manufacturing companies worldwide in all languages using terms: dental implants, dental implant manufacturers and dental implant companies. Once identified, all relevant information including images regarding dental implant products was collected even that for discontinued products. A program was then devised using key design factors to enable identification of individual implants. RESULTS: The searches produced details for 87 implant manufacturers based in 21 countries with 231 different implant designs. The resultant program has been successfully trialled and used in both general dental practice and for forensic identification. CONCLUSION: The program developed provides a valuable adjunct to the identification of implant systems present in patients' mouths.

Dental Implants↗
PubMed2005

Intra-oral temperatures during function.

There has been limited published research assessing the range of oral temperature that the dental hard and soft tissues are exposed to. The temperatures that tooth structure and dental restorations encounter affect the performance of dental materials within the oral environment. This study therefore assessed the range of temperatures that a selected group could tolerate when drinking and also assessed the range of temperatures encountered in various intra-oral sites. These temperature fluctuations are for very brief periods of time but have a wide and varied range. Miniature dataloggers allowed for accurate measurements and recording of temperature from selected sites. The range of temperature recorded amongst the individuals tested shows the protection afforded to the dental hard tissues by the soft tissues of the oral cavity. The maximum and minimum mouth temperatures recorded show that hot fluids can raise the intra-oral temperature of the front teeth to around 70 degrees C and the consumption of iced drinks lowers the same teeth to around 0 degrees C. The range of temperature of hot fluids that can be tolerated by a selected group vary, but this does not seem to be the case for cold fluids. The thermistor beads mounted on the buccal surface of the lower front teeth and the palatal of the upper front teeth are exposed to the greatest temperature fluctuations during drinking fluids from a cup. The importance of these temperatures recorded in terms of dental materials testing and the role of material conductivity warrants further investigation.

Adolescent↗
PubMed2004

Co-registration of magnetoencephalography with magnetic resonance imaging using bite-bar-based fiducials and surface-matching.

OBJECTIVE: To introduce a new technique for co-registration of Magnetoencephalography (MEG) with magnetic resonance imaging (MRI). We compare the accuracy of a new bite-bar with fixed fiducials to a previous technique whereby fiducial coils were attached proximal to landmarks on the skull. METHODS: A bite-bar with fixed fiducial coils is used to determine the position of the head in the MEG co-ordinate system. Co-registration is performed by a surface-matching technique. The advantage of fixing the coils is that the co-ordinate system is not based upon arbitrary and operator dependent fiducial points that are attached to landmarks (e.g. nasion and the preauricular points), but rather on those that are permanently fixed in relation to the skull. RESULTS: As a consequence of minimizing coil movement during digitization, errors in localization of the coils are significantly reduced, as shown by a randomization test. Displacement of the bite-bar caused by removal and repositioning between MEG recordings is minimal ( approximately 0.5 mm), and dipole localization accuracy of a somatosensory mapping paradigm shows a repeatability of approximately 5 mm. The overall accuracy of the new procedure is greatly improved compared to the previous technique. CONCLUSIONS: The test-retest reliability and accuracy of target localization with the new design is superior to techniques that incorporate anatomical-based fiducial points or coils placed on the circumference of the head.

Brain↗
PubMed2002

The effect of thermocycling on five adhesive luting cements.

The importance of bond strengths between dental luting cements and dental restorative materials has become increasingly important as a result of the adhesive technologies that have been developed over recent years. This study investigated the effect on tensile bond strength at the metal to cement interface for a semiprecious alloy for different prepared surfaces, cements and ageing regimes. At 24 h following preparation, silicoating and C & B Metabond appear to have distinct advantages in terms of interfacial bond strength, which was also noted after storage for 7 days in buffered saline. After thermocycling only silicoating conferred greater interfacial tensile strength, and any advantage that the 4-Methacryloxyethyltrimellitic anhydride (4-META) chemistry may have had at 24 h was no longer apparent. The poorest performing cement regardless of the ageing regime was Aquacem, although in relative terms its performance improved after 24 h. This preliminary investigation indicated that in vitro environmental ageing including thermocycling erodes the claimed advantages of some more novel dental adhesives. This may have important clinical consequences in their usage, although it must be appreciated that current thermocycling methodology may not be an accurate predictor of in vivo performance.

Acrylic Resins↗
PubMed2001

A three-part bilateral swinglock design denture revisited.

This case was first reported by one of the authors in 1987, subsequent to the patient being treated using a combination of a hinge and split pin sectional denture. The same patient attended for review some 14 years later for assessment of this denture at which stage a replacement was made.

Aged↗
PubMed2000

A pilot study of intraoral temperature changes.

The aim of this in vivo pilot study was to record variations in temperature at various sites in a subject's mouth in response to a standardised thermal challenge and to determine a more realistic thermocycling regimen for future use. A volunteer who suffered from no dentinal hypersensitivity had modified study models prepared for constructing vacuum-formed PVC splints. Perforations 2 mm in diameter were placed for thermocouples facially and lingually in the midcoronal sites of the upper and lower central incisors, canines, second premolars, and second molars to measure temperatures at these sites. A standardised drinking regimen was followed of hot black coffee (72.5 degrees C) followed by cold orange juice (6.0 degrees C). Contralateral sites experienced similar temperature changes of short duration. A maximum of 68.0 degrees C and a minimum of 15.4 degrees C were recorded. Less extreme temperatures were experienced posteriorly, and little or no discernible changes were noted at the facial aspects of the upper second molars or lingually on the lower second molars. Most commonly used thermocycling regimens are clinically unrealistic, and temperatures vary widely throughout the mouth when hot or cold drinks are taken.

Analysis of Variance↗
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↗
PubMed1994

Case report: a restorative option in the management of hypodontia.

The treatment of hypodontia is a constant challenge to the dental profession but with the advent of bone grafting and implantology, and adhesive dental techniques, we now can offer more alternatives than simply the prosthetic replacement of the missing units. This case report demonstrates the use of modern adhesive techniques to provide a fixed, rather than removable solution.

Adult↗
PubMed1994

The tensile and shear bond strength of a conventional and a 4-meta self-cure acrylic resin to various surface finishes of CoCr alloy.

This study was designed to compare the tensile and shear bond strengths of two self-cure acrylic resins to cobalt-chromium alloy (CoCr) samples, prepared with six surface finishes. The strongest mean tensile bond strength was recorded between the 4-Meta acrylic resin and Silicoated cobalt-chromium alloy. The strongest mean shear bond strengths showed little variation between the 4-Meta acrylic resin and Silicoated, sandblasted and sandblasted/tinplated cobalt-chromium. This laboratory based study may have important implications for the future design of CoCr dentures.

Acrylic Resins↗
PubMedDate not supplied

The clinical assessment of a ceramic-coated transmucosal dental implant collar.

This study compared the superficial tissue responses to titanium and ceramic surfaces of transmucosal elements of established IMZ implants. In a splitmouth study on 14 patients with two mandibular implants and a bar-retained complete mandibular denture, a conventional titanium and a newly developed ceramic-coated transmucosal element were placed. A range of clinical parameters were recorded before transmucosal-element replacement and at 1, 4, and 12 weeks postplacement. A comparison of the recorded soft tissue responses revealed no significant differences between a group of implants fitted with ceramic-coated transmucosal elements and a group of contralateral implants fitted with titanium transmucosal elements. Further analysis suggested that the peri-implant soft tissues adjacent to titanium and ceramic surfaces may differ in features that are not apparent when routine clinical parameters are used. The plaque accumulation scores for ceramic-coated transmucosal elements were significantly lower than those recorded in titanium transmucosal elements. These results suggest that the further development of a ceramic implant transmucosal collar may assist plaque control at the soft tissue-implant interface and may favourably influence the tissues in this region. This investigation should be considered a pilot study in view of the duration of the observations and number of patients involved.

Adult↗