Competency based surgery.
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Competency-Based Education↗
Biomedical subjects
T Renton
Publications and source records attributed to T Renton.
Simplifying the assessment of the recovery from surgical injury to the lingual nerve.
OBJECTIVE: To determine the sensitivity of conventional sensory assessment in monitoring lingual nerve recovery subsequent to third molar surgery and to evaluate if the assessment methods can be predictive of injury outcome. METHOD: A prospective case series of 94 patients presenting with lingual nerve injuries evaluated using objective mechanosensory and subjective methods during the recovery period of up to 12 months. RESULTS: The conventional tests were often unable to diagnose the presence of injury due to variability and they were not predictive of outcome. As a result of this study, we are able to identify patients more likely to have permanent rather than temporary lingual nerve injury at four to eight weeks post injury, using patient reported subjective function. The subjective function test also minimises the requirements for specialist training or equipment providing an ideal method for general dental practice. CONCLUSIONS: The development of these simple subjective tests may enable us to identify which patients are at risk of permanent lingual nerve injuries in the early post injury phase, thus allowing expeditious therapy when indicated.
Cranial Nerve Injuries↗
Sodium channel Nav1.8 immunoreactivity in painful human dental pulp.
BACKGROUND: The tetrodotoxin-resistant voltage-gated sodium channel Nav1.8 (SNS1/PN3) is expressed by nociceptors and may play a role in pain states. METHODS: Using specific antibodies for immunohistochemistry, we studied Nav1.8 immunoreactivity in human dental pulp in relation to the neuronal marker neurofilament. Human tooth pulp was extracted from teeth harvested from a total of twenty-two patients (fourteen without dental pain, eight patients with dental pain). RESULTS: Fibres immunoreactive for Nav1.8, were significantly increased on image analysis in the painful group: median (range) Nav1.8 to Neurofilament % area ratio, non-painful 0.059 (0.006-0.24), painful 0.265 (0.13-0.5), P = 0.0019. CONCLUSION: Nav1.8 sodium channels may thus represent a therapeutic target in trigeminal nerve pain states.
Journal Article↗
A randomised controlled clinical trial to compare the incidence of injury to the inferior alveolar nerve as a result of coronectomy and removal of mandibular third molars.
We randomised 128 patients who required operations on mandibular third molars and who had radiological evidence of proximity of the third molar to the canal of the inferior alveolar nerve to one of two operations: extraction [n=102], and coronectomy [n=94]. Some roots were dislodged during intended coronectomy and were therefore removed, resulting in two subgroups (successful coronectomy n=58, and failed coronectomy n=36). The mean (S.D.) follow up was 25 (13) months. Nineteen nerves were damaged (19%) after extraction, none after successful coronectomy, and three (8%) after failed coronectomy (p=0.01). The incidence of dry socket infection was similar in the three groups (10/102, 10%, 7/58, 12%, and 4/36, 11%, respectively). No root required removal or reoperation. To our knowledge this is the first clinical trial of the efficacy of coronectomy in preserving the inferior alveolar nerve. The length of follow up was about 2 years, which for the assessment of delayed eruption of the root fragments is not sufficient as this process may continue for up to 10 years. However, it seems that coronectomy reduces the incidence of injury to the inferior alveolar nerve without increasing the risk of dry socket or infection.
Adult↗
Objective evaluation of iatrogenic lingual nerve injuries using the jaw-opening reflex.
The extent of reflex inhibition of masseteric electromyographic activity, after an electrical stimulus applied to lingual mucosa, was used as a test of the ability of the lingual nerve to conduct nerve impulses and this was compared with the results of standard clinical tests. Two groups of subjects were assessed: healthy subjects (n=10) and patients with lingual nerve injuries (n=17). The patients were tested 8-9 weeks after their injury and retested 6 months later when they were retrospectively allocated to either a temporary injury or a permanent injury group. The group measure of reflex inhibition after stimulation of the tongue on the opposite side to the injury was no different from the same measure in controls, whereas two-point discrimination did differ. Group measures of inhibition and of subjective function after stimulation on the side of the injury were significantly different from controls whereas light touch and two-point discrimination were not. There was good agreement between quantified masseteric inhibition and subjective function, but it was not possible at 8-9 weeks after the injury to differentiate between those that would recover and those that would be permanent.
Adult↗
New method for the objective evaluation of injury to the lingual nerve after operation on third molars.
Existing tests of function of the lingual nerve are either subjective or, when they elicit the jaw-opening reflex, are dependent on the cooperation of the subject. We report a study in 12 healthy volunteers and 12 patients with iatrogenic injury to the lingual nerve. A bite block (containing stimulating electrodes) was held between the teeth and the tongue was held on to the electrodes by suction. When the lingual nerve was intact, an electrical stimulus elicited brief inhibition of masseteric electromyographic activity. Local analgesia and iatrogenic injury to the lingual nerve altered nerve conduction and caused a reduction in reflex inhibition. Two methods, compatible with limited numbers of applications of the stimulus, were used to quantify responses. One used an indirect measurement of intervals between action potentials of muscle and the other used a measurement of rectified signals falling below the mean amplitude before and after the stimulus. Both methods gave values that correlated with subjective sensations. The first gave an estimate of the probability of defining major malfunction of the nerve objectively; the second gave a linear measurement that allowed recovery of the nerve to be followed.
Action Potentials↗
Quantitative thermosensory testing of the lingual and inferior alveolar nerves in health and after iatrogenic injury.
Quantitative testing of the sensory thermal thresholds testing was applied at sites innervated by the third division of the trigeminal nerve in 20 patients with no reported sensory impairment and in 20 subjects with iatrogenic nerve injuries after third molar surgery. In the control group sensitivity to cooling was significantly greater than the sensitivity to warming at all sites. The labial mucosa innervated by the inferior alveolar nerve was significantly more sensitive to thermal changes than either the mental region or the lingual mucosa. At sites supplied by nerves that had been injured, there were raised thresholds to both warming and cooling compared with the control group, and with uninjured contralateral sites. The results indicate that this test can identify iatrogenic lingual and inferior alveolar nerve injury with reference to a control group but because of spatial variation selection of control sites for comparison should be done cautiously.
Adolescent↗
Differential diagnosis and treatment of autosomal dominant osteosclerosis of the mandible.
A 20-year-old patient who presented with concerns about her large mandible was found to have a generalized mild cortical sclerosis. She was treated successfully with staged orthognathic surgery, despite the dense sclerosis of the jaws.
Adult↗
Factors predictive of difficulty of mandibular third molar surgery.
AIM: Historically the difficulty of third molar surgery has been judged using radiologically assessed dental factors specifically tooth morphology and position. This study investigated additional factors that have a bearing on the difficulty of extraction. STUDY DESIGN: A prospective study undertaken by three clinical assistant grade surgeons who removed 354 single mandibular third molar teeth under day case anaesthesia over the 4-year period (1994-1998). METHOD: Data relating to patient, dental and surgical variables were collected contemporaneously as the patients were treated. The difficulty of extraction was estimated by the surgeons pre-operatively using dental radiographic features and compared by the same surgeon within the actual surgical difficulty encountered at surgery. Operation time strongly related to both pre and post treatment assessments of difficulty and proved to be the best measure of surgical difficulty. RESULTS: Univariate analysis identified increased patient age, ethnic background, male gender, increased weight, bone impaction, horizontal angulation, depth of application, unfavourable root formation, proximity to inferior alveolar canal and surgeon as factors increasing operative time. Multivariate analysis showed that increasing age (P = 0.014), patient weight (P = 0.024), ethnicity (P = 0.019), application depth (P = 0.001), bone impaction (p=0.008) and unfavourable root formation (P = 0.009) were independent predictors for difficulty of extraction. CONCLUSIONS: Half of the six independent factors that predicted surgical difficulty of third molar extraction were patient variables.
Adolescent↗
Evaluation of factors predictive of lingual nerve injury in third molar surgery.
The aim of this study was to investigate risk factors for temporary and permanent lingual nerve injury after extraction of mandibular third molars. It was based on a 4-year prospective study of 2134 consecutive mandibular third molar operations in 1384 consecutive day case patients. During the study period (1994-1998) data were collected prospectively on patient, dental and surgical factors and correlated with lingual nerve injury using Student's t test, xi(2) and multiple logistic regression analysis. The incidence of temporary and permanent lingual nerve injury was 1 and 0.3%, respectively, per tooth. Factors that predicted temporary and permanent lingual nerve injury by univariate analysis were age, depth of application, difficulty of operation, surgeon and surgical technique used. Independent risk factors identified by multivariate analysis for temporary lingual nerve injury were perforation of the lingual plate, exposure of the nerve and increased difficulty of operation. The predictors for permanent lingual nerve injury in order of importance were perforation of the lingual plate, surgeon, increased difficulty of operation, exposure of the nerve and increased age of the patient. Surgical factors are the main contributors to lingual nerve injury during third molar extraction, but patient and dental factors are also involved.
Adolescent↗
Radiographic protocols.
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Clinical Protocols↗
An investigation into the efficacy of intravenous diclofenac in post-operative dental pain.
OBJECTIVE: To evaluate the efficacy of single doses of intravenous diclofenac sodium (25, 50 and 75 mg) in patients with post-operative pain after third-molar surgery in a randomised, placebo-controlled study. METHODS: Two hundred and sixty-nine patients (168 females) who required the removal of their impacted third molars participated in the study, which had received prior ethical approval. Surgery was completed under general anaesthesia and, during the early post-operative period, patients received either a single intravenous dose of diclofenac (25, 50 or 75 mg) or matched placebo in random, double-blind order. Pain intensity was assessed on 10-cm visual analogue scales at fixed time points throughout a 4-h investigation period. Other efficacy variables obtained included time until rescue medication and overall assessment at 4, 6, 12 and 24 h after dosing. RESULTS: Throughout the 4-h investigation period, patients treated with diclofenac reported significantly less pain than those treated with placebo (P < 0.001). No differences were observed among the three doses of diclofenac (P = 0.22). Similar results were observed at 6, 12 and 24 h after dosing. Significant differences were also noted between the placebo group and all the diclofenac treatment groups with respect to time until rescue medication (P < 0.001) and the proportion of patients taking such medication. CONCLUSION: Single doses of i.v. diclofenac (25, 50 and 75 mg) provide significant pain relief after third-molar surgery. The efficacy of this preparation does not appear to be dose related.
Adult↗
More to consider in nerve injury debate.
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Anesthesia, Dental↗
Direct referral day case oral surgery for dental practitioners: a pilot investigation.
Direct referral of patients for day case surgery by general medical practitioners (without hospital assessment) has become widely accepted but few facilities exist for this form of referral from general dental practice. In order to evaluate whether direct access day surgery is applicable to dentistry, the quality of referral by GDPs and hospital consultant clinics was compared in a prospective study (1994-1997) involving 1581 patients.
Ambulatory Surgical Procedures↗