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Biomedical subjects

A N Stokes

Publications and source records attributed to A N Stokes.

At least 19 recordsLinked to original sources
PubMed1995

A survey of tooth injury experience and attitudes to prevention in a group of Singapore schoolboys.

A survey of 246 boys aged 12-17 years (mean 13.8 years) determined the sports played, dental injury experience, knowledge and usage of and attitudes towards mouthguard wearing. Most played basketball and soccer. Twenty-one suffered 1 injury episode, 7-2 and 10-3 or more tooth injuries. Twenty-six subluxations, 19 fractures and 1 avulsion were reported. The sports with the highest prevalence of dental injury were boxing and wrestling (33%), soccer (20%), and basketball (19%). While 144 (56%) of boys knew about mouthguards, none wore one. Only 64 (25%) would wear a mouthguard if given one. Most dental injuries were minor, but four high-risk sports (> 19% injury prevalence) would justify preventive measures, including education for injury prevention and encouragement of mouthguard use.

Adolescent↗
PubMed1992

Lay and professional knowledge of methods for emergency management of avulsed teeth.

Proper treatment during the first 30 minutes offers the best prognosis for traumatically avulsed teeth. This study sought to determine both lay people's and dental professionals' knowledge of and attitude to emergency procedures. A 12-question survey was administered to 5 groups: (a) parents of learner swimmers and (b) coaches of college sports teams (lay); (c) State Dental Nurses, (d) dentists and (e) dental nurse/receptionists (professional). Respondents totalled 184 (a 32, b 86, c 24, d 18, e 24) i.e. 118 lay and 66 professional. Data revealed that group b had the greatest personal experience of avulsed teeth and groups c and e the least. Public hospital accident and emergency services (A & E) were perceived by all groups as most available. 18% of lay groups could not cite an emergency service. Lay people thought first of A & E for management whereas profession groups preferred the victim's own dentist. Most professional people would replant avulsed permanent teeth and about 1/3 would replant deciduous teeth: 1/2 lay people would replant permanent teeth and 1/8 deciduous teeth. Where treatment was not straightforward lay people would seek advice before acting. Half of the lay groups would transport an avulsed tooth dry. All the professionals had had advice on management of avulsed teeth but only 1/4 of the lay groups. This study highlighted the need for educational campaigns aimed at members of the lay public likely to be involved in the emergency management of traumatically avulsed teeth.

Attitude of Health Personnel↗
PubMed1992

Effect of peroxide bleaches on resin-enamel bonds.

Human third molar teeth were divided into three groups: untreated control; enamel treated with 35% hydrogen peroxide for 2 hours; and enamel treated with 10% carbamide peroxide gel for 14 days. All teeth were ground to present a flat enamel surface, to which cylinders of light-cured composite resin were bonded. Shear bond strengths were determined for each specimen. The mean shear bond strengths of resin-enamel bonds after pretreatment with both 35% hydrogen peroxide and 10% carbamide peroxide were significantly lower than those for untreated controls. External bleaching with these materials prior to resin bonding procedures may reduce the quality of resin-enamel bonds.

Acrylates↗
PubMed1990

Effectiveness of sterilisation and disinfection procedures for dental amalgam carriers.

The potential for cross infection through dental amalgam carriers was investigated in 37 Dunedin dental practices and in the University of Otago School of Dentistry. Eighteen practitioners had autoclavable carriers, but only 2 autoclaved them at least daily. The School of Dentistry disinfected plastic carriers and autoclaved metal carriers. Microbiological examination, by culturing from the most commonly contaminated carrier site, showed that the School of Dentistry method for disinfection of plastic carriers was unreliable. Autoclaving was confirmed as the preferred method of sterilisation, but many existing carriers are not suited to this technique.

1-Propanol↗
PubMed1990

Influence of cavosurface configuration and composite resin type on impact fracture resistance of Class IV restorations.

The fracture behaviours of intact maxillary central incisor teeth, and teeth restored by five different composite resins utilising uninstrumented fractured etched margins and bevelled etched margins, were determined by a pendulum impact method. It was established that: 1. Intact teeth fractured in a predictable manner when struck by a pendulum hammer at predetermined points on the labial surfaces close to incisal angles. 2. The impact resistance of teeth with bevelled margin restorations was significantly greater than that of teeth restored using the uninstrumented fractured margins. 3. Differences in impact resistance between intact teeth and teeth restored with bevelled margins were not significant. 4. There was no significant difference in fracture energy between any of the composite resin materials in either the uninstrumented joint or bevelled joint modes. 5. For all restorations placed on uninstrumented margins, the fracture paths were at or near the adhesive interface; no restorations failed cohesively. 6. Fracture paths in the bevelled joint mode were variable, with fracture occurring either entirely in enamel, or entirely in composite resin, or at the interface.

Acrylic Resins↗
PubMed1990

Eye protection in dental practice.

A survey of Southland dental practices showed that eye protection for dentists, dental surgery assistants, and patients did not generally meet currently recommended standards. The prevalence of eye injuries was low but, because of the random nature of many eye injuries, all practitioners should maintain proper protective procedures.

Adolescent↗
PubMed1989

Thermocycling, silane priming, and resin/porcelain interfaces interfaces--an electrical leakage study.

High 24-hour tensile and shear bond strengths have been reported for silane-primed resin/porcelain interfaces, but bonds often failed after prolonged water storage. This study was designed to determine the influences of both a silane primer and thermocycling on interfacial leakage between a light-cured BisGMA resin and dental porcelain. Porcelain discs measuring 10 mm in diameter and 1.5 mm in thickness were fired. Axial cylindrical cavities were prepared through the discs with a diamond bur. Four groups of eight discs each were restored in the following modes: groups 1 and 2 with light-cured bonding agent and light-cured microfilled resin, and groups 3 and 4 with a silane primer followed by the same bonding agent and resin. Specimens were water-stored for 24 hr, after which those in groups 2 and 4 were thermocycled 200 times between 4 degrees C and 60 degrees C. Specimens were then sealed to steel anodes and placed in 1% KCl, maintained at 21 degrees C, around a stainless steel cathode. Leakage currents were recorded daily for 30 days and after six months, by application of a 10 V potential difference between the cathode and each anode. Positive and negative controls gave massive and nil readings, respectively. The mean leakages were consistently greatest in group 2 (being significantly greater than for the other groups). Results suggest that silane priming minimizes leakage at the resin/porcelain interface after thermal cycling.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1989

Influence of casting procedure on silver-palladium endodontic posts.

Silver-palladium alloys have been endorsed on clinical grounds as substitutes for gold alloys in posts and cores. However, carbon absorption during heating and casting can adversely affect the mechanical properties of silver-palladium alloys. In this study the tensile characteristics of endodontic posts cast in silver-palladium alloy using either a graphite or a ceramic crucible were determined. Graphite crucibles were associated with a significantly lower (2P less than 0.00001) percentage elongation than were ceramic crucibles. The need for a carbon-free casting environment for silver-palladium alloys was confirmed. The configuration of the cylindrical, serrated, vented post used in these tests resulted in mechanical properties lower than those achieved with standard metallurgical test procedures.

Ceramics↗
PubMed1987

Impact-fracture energy of human premolar teeth.

The fracture strength of contralateral pairs of premolar teeth was determined by an in vitro method wherein impact loads of equal energy were applied to the medial aspects of the buccal cusps. Absorbed energy values quantified the fracture resistance of unprepared teeth and teeth restored with MOD amalgams, MOD amalgam overlays, MOD gold overlays, and full gold crowns. It was established that unprepared lower premolar teeth had a greater resistance to fracture than upper premolar teeth, and lower first premolar teeth were more resistant to fracture than the other premolar teeth; the fracture resistance of premolar teeth restored with MOD amalgams was significantly reduced compared with unprepared control teeth; MOD amalgam overlays in premolar teeth produced fracture resistances not significantly different from those for the unprepared controls; and restoration of premolar teeth with MOD gold overlays and full gold crowns enhanced fracture resistance to a level much greater than that of the unprepared control teeth.

Bicuspid↗