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Biomedical subjects

J G Meechan

Publications and source records attributed to J G Meechan.

At least 19 recordsLinked to original sources
PubMed2006

A comparison of the aspirating abilities of re-usable and partly disposable dental cartridge syringes in vitro.

OBJECTIVES: To compare the ability of re-usable and partly disposable dental cartridge syringes to aspirate in vitro. METHODS: A laboratory investigation comparing two re-usable (Astra and Rotor) and one partly disposable (Ultra Safety-plus) dental cartridge syringes. Forces needed to move the cartridge plunger and forces required to produce aspiration of Bonney's Blue dye were measured using an Instron testing machine. RESULTS: There were significant differences in the forces needed to produce aspiration in the different systems (F = 194, p<0.001). The Astra system needed the least force to produce aspiration. The forces required to aspirate in the Rotor and Ultra Safety-plus systems did not differ. Each system aspirated effectively in vitro at the initial aspiration manoeuvre. The forces available for subsequent aspiration attempts varied with the speed of cartridge plunger movement. The volume of local anaesthetic cartridge used did not affect the force needed to produce aspiration in the Ultra Safety-plus syringe. The method of testing free-flow of solution through the needle affected the force generated at subsequent plunger movements. CONCLUSIONS: The re-usable and partly disposable syringes investigated aspirated effectively at the initial aspiration manoeuvre. The force available to produce aspiration at subsequent attempts varies with the speed of injection. The method of testing free-flow of solution through the needle in a loaded syringe affects the force available at the first aspiration manoeuvre.

Anesthesia, Dental↗
PubMed2005

Pressures generated in vitro during Stabident intraosseous injections.

AIM: To test the hypothesis that the Stabident intraosseous injection is a potentially high-pressure technique, which carries serious risks of anaesthetic cartridge failure. METHODOLOGY: A standard Astra dental syringe was modified to measure the internal pressure of local anaesthetic cartridges during injection. Intra-cartridge pressures were measured at 1 s intervals during slow (approximately 15 s) and rapid (<10 s) injections of 2% Xylocaine with 1:80,000 adrenaline (0.25 cartridge volumes) into air (no tissue resistance), or into freshly prepared Stabident perforation sites in the anterior mandible of freshly culled young and old sheep (against tissue resistance). Each injection was repeated 10 times over 3 days. Absolute maximum pressures generated by each category of injection, mean pressures at 1 s intervals in each series of injections, and standard deviations were calculated. Curves of mean maximum intra-cartridge pressure development with time were plotted for slow and rapid injections, and one-way anova (P<0.05) conducted to determine significant differences between categories of injection. RESULTS: Pressures created when injecting into air were less than those needed to inject into tissue (P<0.001). Fast injection produced greater intra-cartridge pressures than slow delivery (P<0.05). Injection pressures rose more quickly and to higher levels in small, young sheep mandibles than in larger, old sheep mandibles. The absolute maximum intra-cartridge pressure developed during the study was 3.31 MPa which is less than that needed to fracture glass cartridges. CONCLUSIONS: Stabident intraosseous injection conducted in accordance with the manufacturer's instructions does not present a serious risk of dangerous pressure build-up in local anaesthetic cartridges.

Age Factors↗
PubMed2003

General medicine and surgery for dental practitioners Part 9: haematology and patients with bleeding problems.

Disorders of the blood can affect the management of dental patients. Particular oral signs may be produced. In addition healing may be affected and the choice of anaesthesia for operative procedures will be influenced. Similarly, patients who have problems with haemostasis are a concern. Surgical procedures are obvious problems. However, restorative dentistry is not trouble-free as patients with bleeding problems may present difficulties regarding the choice of local anaesthesia, as regional block techniques may be contraindicated in some patients.

Anesthesia, Dental↗
PubMed2003

General medicine and surgery for dental practitioners. Part 8: Musculoskeletal system.

Disorders of the musculoskeletal system may impact on dental management in diverse ways. Diseases of the bones may have a direct influence on treatment and joint disorders can also cause difficulties. Cervical spine involvement may lead to poor neck extension causing difficulties in providing dental treatment under local anaesthesia or allowing the provision of a safe general anaesthetic. Muscular disorders may mitigate against safe general anaesthesia. As with all medical disorders a thorough history can help to prevent many of the possible problems which may occur secondary to musculoskeletal diseases.

Anesthesia, Dental↗
PubMed2003

General medicine and surgery for dental practitioners. Part 7: renal disorders.

Patients with kidney disorders are increasingly encountered in dental practice due to improvements in medical care leading to prolonged life expectancy. In order to provide appropriate and safe dental care for these patients it is important to have a working knowledge of renal disorders and related problems.

Candidiasis, Oral↗
PubMed2003

General medicine and surgery for dental practitioners. Part 5: liver disease.

The liver has a number of important functions. It metabolises drugs and endogenous substances and contributes to their excretion by the body. Plasma proteins are synthesised in the liver which also acts as a storage organ for glycogen and vitamin B12. The liver is also important in the production of clotting factors for normal haemostatic function.

Anesthesia, Dental↗
PubMed2003

General medicine and surgery for dental practitioners. Part 3: gastrointestinal system.

Diseases of the gastrointestinal (GI) system can be relevant to the dental surgeon for several reasons. The mouth may display signs of the disease itself, for example the cobblestone mucosa, facial or labial swelling of Crohn's disease, or the osteomata of Gardner's syndrome. These are well covered elsewhere and not discussed further here. The sequelae of GI disease, for example gastric reflux producing dental erosion, iron deficiency anaemia and treatment such as corticosteroid therapy may all have a bearing on management and choice of anaesthesia.

Anesthesia, Dental↗
PubMed2003

The interdisciplinary management of hypodontia: restorative dentistry.

This paper considers the role of restorative dentistry in the management of hypodontia. The paper describes the general restorative considerations common to patients with hypodontia and illustrates the variety of restorative techniques available in the restorative management of hypodontia and oligodontia.

Anodontia↗
PubMed2003

The interdisciplinary management of hypodontia: background and role of paediatric dentistry.

This paper is the first of a series on the comprehensive management of young people with hypodontia. The paper looks at the background to the condition, the possible aetiological factors, the prevalence of hypodontia and other related conditions. Lastly there is consideration of the role of the paediatric dentist in interdisciplinary management of the affected child and adolescent patient.

Adolescent↗