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Biomedical subjects

J G Meechan

Publications and source records attributed to J G Meechan.

At least 73 records · Page 4Linked to original sources

The effect of storage temperature on the resistance to failure of dental local anesthetic cartridges.

This in vitro investigation studied the effect of storing dental local anesthetic cartridges at room temperature and at 37 degrees C on the forces required for cartridge failure under strong injection pressures. Storage for three hours at the higher temperature resulted in a significant reduction in the forces required to produce failure of plastic cartridges (leakage of solution around the bung). The forces needed to cause failure of glass cartridges did not differ between the two temperatures.

Anesthesia, Dental↗

A comparison of the effects of EMLA cream and topical 5% lidocaine on discomfort during gingival probing.

This investigation compared the use of a 5% eutectic mixture of local anesthetics (EMLA) cream to a "standard" intraoral topical anesthetic (5% lidocaine) as a means of anesthetizing the gingival sulcus in a double-blind, split-mouth study with human volunteers. A 5-min application of EMLA in a customized intraoral splint resulted in a significant increase in the depth of probing of the gingival sulcus without discomfort compared to a similar application of 5% lidocaine. Following application of EMLA, the pain-free probing depth measured at three sites in the upper premolar region increased by a mean total of 2.8 mm compared to an increase of 1.9 mm with lidocaine. This study suggests EMLA may be advantageous in providing periodontal anesthesia where manipulation of the gingiva is necessary.

Administration, Topical↗

Adhesion of composite resin to bone--a pilot study.

This pilot study investigated the adhesion of composite resin to pig calvarium using All-bond 2 dentine bonding agent in an in vitro model. The bone was subjected to different methods of preparation. Acid-etching decreased the bond strength between bone and composite. Roughening the bone with a surgical bur prior to application of the adhesive produced bond strengths in the range 11.1-16.1 MPa.

Animals↗

Self-medication for the control of dental pain: what are our patients taking?

As all dental practitioners are aware, patients suffering from dental pain often self-medicate with over-the-counter (OTC) analgesics in order to alleviate their symptoms: indeed, some patients seem to view the use of these drugs as a means of avoiding the need for dental attendance altogether. The use (and abuse) of such medication is entirely under the control of the patient. The study reported in this article shows which commonly available analgesics are chosen by patients and how effective they are considered to be. The authors also assess the overall pattern of analgesic self-medication, and discuss the problem of over-consumption.

Acetaminophen↗

The use of third molar surgery in clinical pharmacology.

This review discusses the various sequelae that arise after third molar surgery and their use for assessing the efficacy of a variety of therapeutic measures. The surgical procedure provides an opportunity to investigate onset, depth, duration and possible systemic effects of local anaesthetic solutions. Also, the anxiety which often accompanies such surgery lends itself to the appraisal of different anxiolytic agents and sedation techniques. The immediate postoperative sequelae of pain, buccal swelling and trismus provides a useful clinical model for evaluating the efficacy of analgesics and anti-inflammatory drugs. Third molar tooth sockets are susceptible to infection and this propensity enables the assessment of different antibiotic regimens. A further advantage of the third molar model is its application for crossover studies, with the patient acting as their own control. Very few surgical procedures afford this facility, which further adds to the value of this model in clinical pharmacology.

Analgesics↗

Juvenile xanthogranuloma of the oral cavity: a case report.

A 3 1/2-year-old girl presented with a symptomless lump on her tongue which had been present for 8 months. A provisional diagnosis of fibroepithelial polyp was made and no treatment was carried out. Six months later the lump had increased in size and it was excised. Histological examination led to a diagnosis of juvenile xanthogranuloma. One year later the lesion had not recurred.

Child, Preschool↗

Minor oral surgery for children: 1. Medical problems influencing management.

This is the first paper in a series which will deal with exodontia and minor oral surgery for child patients. This first article is concerned with medical conditions that influence the management of children; subsequent papers will consider methods of pain control and surgical techniques for young patients. The final article will give an account of our experience in the provision of exodontia and minor oral surgery for children under local anaesthesia and relative analgesia. Suggestions for further reading will be provided with the final paper.

Child↗

Aspiration in dental local anaesthesia.

When injecting into a blood vessel (for example during intravenous sedation) it is essential to aspirate blood into the syringe prior to drug administration to ensure that the tip of the needle is lying within a vein. By the same token, when the injection is intended to be extravascular it would appear to be wise to ensure that no blood is aspirated into the syringe before drug delivery. This procedure is employed routinely by medical and nursing staff, but is not universally accepted by dentists prior to the administration of dental local anaesthetics.

Anesthesia, Dental↗

The effects of two different local anaesthetic solutions administered for oral surgery on plasma potassium levels in patients taking kaliuretic diuretics.

The effects of two different dental local anaesthetic solutions, administered for oral surgery, on the plasma potassium levels of patients taking non-potassium sparing diuretics has been investigated. There was a significant reduction in plasma potassium concentration in eight subjects who received 4.4 ml of 2% lignocaine with 1:80,000 adrenaline; the mean reduction from baseline being 0.30 mmol.l-1 10 min following intraoral extravascular injection of the local anaesthetic. There was no significant difference from the pre-treatment plasma potassium concentration 10 min following similar injections of 3% prilocaine with 0.03 IU.ml-1 felypressin in 8 patients; the mean change in these subjects being -0.05 mmol.l-1. It is suggested that the use of adrenaline-free local anaesthetics would seem to be appropriate in patients receiving kaliuretic diuretics.

Aged↗

Effect of different storage methods on the performance of dental local anaesthetic cartridges.

Self-aspirating dental local anaesthetic syringe systems rely on deformation of rubber diaphragms contained in the anaesthetic cartridges to produce the aspirating force. A test has been developed which can examine the performance of these rubber diaphragms under functional conditions. This method could be useful in the production of standards for dental local anaesthetic cartridges. The test has been used to determine the influence of storage conditions on the performance of dental local anaesthetic cartridges. The results show that, with the cartridges investigated, storage at 37 degrees C increased the amount of distortion per unit force of the aspirating diaphragms in comparison with storage at room temperature. However recovery of the diaphragms was unaffected. Storage at the higher temperature decreased the amount of force required to initiate movement of the cartridge rubber bung during injection. Soaking cartridges in alcohol did not affect the distortion of the aspirating diaphragms or the force needed to move the bung during injection, but did increase the degree of recovery of the diaphragm in the bung of self-aspirating cartridges.

Anesthesia, Dental↗

Intraligamentary anaesthesia.

The introduction of specialized syringes in the late 1970s and early 1980s has led to an increase in the use of intraligamentary anaesthesia as a means of pain control in dentistry. This paper reviews the technique and its efficacy and considers the advocated advantages and disadvantages of the method in the light of the published scientific evidence. It is concluded that intraligamentary anaesthesia has a role to play in modern dental local anaesthesia but it does not fulfil all the requirements of a primary technique.

Anesthesia, Dental↗

Metabolic responses to oral surgery under local anesthesia and sedation with intravenous midazolam: the effects of two different local anesthetics.

The effects of epinephrine-free and epinephrine-containing local anesthetic solutions on plasma potassium and blood glucose concentrations were investigated in 20 patients undergoing oral surgery with intravenous midazolam sedation. Ten patients were randomly assigned to receive 4.4 mL of 2% lidocaine with 1:80,000 epinephrine as a local anesthetic and 10 were given 4.4 mL of 3% prilocaine with 0.03 IU/mL felypressin. There were significant changes from baseline potassium and glucose concentrations both within and between treatments in the early postinjection period. The epinephrine-containing local anesthetic significantly reduced the plasma potassium concentration 10 min after injection, by 0.16 +/- 0.20 mmol/L (mean +/- SD), and increased the blood glucose concentration at 10, 20, and 30 min (by 0.46 +/- 0.37, 0.63 +/- 0.45, and 0.56 +/- 0.28 mmol/L, respectively). Conversely, plasma potassium increased and blood glucose decreased 10, 20, and 30 min following the administration of the epinephrine-free solution. At 30 min potassium was increased by 0.24 +/- 0.16 mmol/L, and glucose was decreased by 0.23 +/- 0.16 mmol/L. It is concluded that epinephrine-free and epinephrine-containing local anesthetics differ in their metabolic effects during oral surgery with midazolam sedation.

Adult↗

The effects of dental local anaesthetics on blood glucose concentration in healthy volunteers and in patients having third molar surgery.

The effects of adrenaline-containing and adrenaline-free dental local anaesthetic solutions on blood glucose concentration were investigated in single-blind cross-over studies in ten healthy volunteers and in ten patients having lower third molar surgery. The solutions compared were 2% lignocaine containing 1:80,000 adrenaline (Xylocaine) and 3% prilocaine with 0.03 IU/ml felypressin (Citanest). In all cases, 4.4 ml of solution was used. In the volunteer study the blood glucose concentration increased from 4.48 +/- 0.72 mmol/litre immediately before the injection of Xylocaine to 5.07 +/- 0.99 mmol/litre 30 minutes following the injection; with Citanest the pretreatment concentration of 4.56 +/- 0.92 mmol/litre changed to 4.24 +/- 0.62 mmol/litre at 30 minutes. This increase in blood glucose concentration following the administration of Xylocaine was significant (t = 3.39, P less than 0.01), as was the difference between treatments (t = 2.64, P less than 0.05). In the patient study, the blood glucose level prior to the injection of Xylocaine was 4.56 +/- 1.59 mmol/litre and this increased to 5.24 +/- 0.86 mmol/litre 30 minutes after the local anaesthetic was injected. The pretreatment blood glucose level of 4.52 +/- 0.82 mmol/litre in patients when Citanest was used changed to 4.33 +/- 0.71 mmol/litre 30 minutes following the injection. The difference at 30 minutes in the changes in blood glucose concentration between local anaesthetic regimes in patients having third molar surgery was significant (t = 2.60, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

The biochemical and haemodynamic effects of adrenaline in lignocaine local anaesthetic solutions in patients having third molar surgery under general anaesthesia.

The effects of adrenaline-containing and adrenaline-free lignocaine local anaesthetic solutions injected in doses consistent with clinical practice on plasma potassium concentration, blood glucose levels and haemodynamic responses were investigated in 20 patients having third molar surgery under general anaesthesia. All patients received a standard general anaesthetic regime. Ten patients were given 4.0 ml of 2% lignocaine as an inferior dental and long buccal block during their general anaesthetic and the other 10 received 4.0 ml of 2% lignocaine containing 1:80000 adrenaline in the same manner. There were no significant differences between treatments in blood pressure or heart rate. However, there were significant differences between treatments in plasma potassium concentration and blood glucose levels.

Adult↗

Plastic dental local anaesthetic cartridges: a laboratory investigation.

The pressures applied to the bungs of glass and plastic dental local anaesthetic cartridges which were necessary to cause failure of the system were measured. Plastic cartridges did not fracture, but they failed due to leakage of solution around the bung at pressures less than those needed to break glass cartridges. At the peak injection pressures which may be obtained during intraligamentary injections, it was established that the theoretical incidence of failure was 1.4% for glass and 75.1% for plastic cartridges.

Anesthesia, Dental↗