The anatomy of local anesthesia.

This article has attempted to present a realistic assessment of the complexities and variability of the anatomic structures related to the induction of profound clinical local anesthesia. By reviewing this material with a good atlas of anatomy (or preferably a human skull), the clinician can better visualize the important relationships described. The firm understanding of all of these relationships that will result is necessary to treating patients with maximum comfort, confidence, and safety.

The anatomy of local anesthesia.

The trigeminal nerve is the great sensory nerve of the facial portion of the head, and an intimate knowledge of this nerve and its surrounding structures is a prerequisite to the application of structures is a prerequisite to the application of profound local anesthesia without complication. In this review article, the classic description of the relevant anatomy is presented and updated with recently published research into anatomic variations that have an impact on the induction of clinical local anesthesia. Causes of both failure and complications of traditional local anesthetic techniques are explained, and recommendations for avoiding these pitfalls are made.

The anatomy of local anesthesia.

The trigeminal nerve is the great sensory nerve of the facial portion of the head, and an intimate knowledge of this nerve and its surrounding structures is a prerequisite to the application of profound local anesthesia without complication. In this review article, the classic description of the relevant anatomy is described and is updated with recently published research into anatomic variations that have an impact on the induction of clinical local anesthesia. Causes of both failure and complications of traditional local anesthetic techniques are explained, and recommendations for avoiding these pitfalls are made.

Solitary eosinophilic granuloma (histiocytosis X) of the gingiva. A report of two cases.

Two cases are reported in which the patients presented with solitary ulcers on the gingiva. The lesions were excised and examined histologically. A connective tissue infiltrate of large mononuclear cells was identified with immunohistochemical staining as Langerhans cells and a diagnosis of histiocytosis X was made. Further medical evaluation revealed no other lesions in one of the patients but did locate an infiltrate in the right mastoid of the other patient. Solitary lesions of histiocytosis in oral mucosa are extremely rare. The manifestations of the disease, pathogenesis, and treatment are discussed.

Incidence and extent of venous sequelae with intravenous diazepam utilizing a standardized conscious sedation technique. Part II: Effects of injection site.

The effects of site of venipuncture on the incidence of venous sequelae, utilizing a standard protocol, were assessed on 48 human subjects. Data were also recorded based on various demographic and clinical variables, including age, sex, race, vein diameter, dose, procedure time, IV fluid volume, injection pain and initial blood flow velocity. When the site of venipuncture was the antecubital fossa there was a significantly lower incidence of venous sequelae than when the venipuncture site was the dorsum of the hand, with the significant variables being venous diameter and procedure time. These findings further support the antecubital fossa as a preferred venipuncture site to the dorsum of the hand; however, there was a sufficient incidence of venous complications (37%) when the antecubital fossa was used to warrant consideration of contributory factors other than site. It appears that time of continuous infusion is a critical element and should be kept at a minimum. Also, subjects in whom Valium was injected demonstrated significantly more venous sequelae than those in whom 5% dextrose in water was injected, confirming previous reports that diazepam is irritating to the endothelial lining and thus is thrombogenic.

An analysis of the variations in position of the greater palatine foramen in the adult human skull.

Three hundred dry, adult human skulls, of East Indian ethnic background, and homogenous in arch form and full eruption of third molars, were examined to measure the location of the greater palatine foramen. The greater palatine foramen was found consistently to lie 1.5 cm from the palatal midline and 0.19 cm from the posterior border of the hard palate. This relationship is suggested as a more accurate method of locating the foramen clinically. The usually accepted description (opposite the second molar) of the relative position of the greater palatine foramen to the upper teeth held in only 9.7% of the skulls studied. This study shows the most common position of the foramen to be opposite or distal to the third molar (57%). The direction of opening of the foramen into the oral cavity was observed to be in an inferior or vertical direction in 247 (82%) of the 300 skulls; in 53 (18%) of the skulls the direction was anterior or horizontal. A bony projection, similar to the mandibular lingula, was observed extending from the posterior margin of the foramen in 95 (16%) of the 600 separate foramina examined. The bilateral symmetry between the sides of the skulls studied was remarkable.

Incidence of thrombophlebitis in humans with the diazepam vehicle.

Forty-one adult males volunteered for a study designed to investigate the thrombogenicity of the Valium® vehicle. Utilizing a standardized protocol, each subject received a sedative dose of Injectable Valium® in the antecubital fossa of one arm and an equivalent volume of vehicle in the contralateral arm. Both were administered with a continuous infusion drip of 5 per cent dextrose in water. Post-operative evaluation extended over 10 weeks and included clinical observation and palpation. Ultrasonic tests for occluded or impaired blood flow were performed with a Doppler Flowmeter.Five subjects (12.2 percent) had venous sequelae with the Valium® and two (4.8 percent) developed sequelae with the vehicle. The incidence of venous sequelae reported in the present study was considerably lower than in previous investigations (66.6 per cent and 37.5 per cent) utilizing the same protocol. The present study indicates that time of continuous infusion appears to contribute to thrombophlebitis subsequent to intravenous injection of Valium®. It also appears that the diazepam vehicle is not the major factor in the occurrence of thrombophlebitis.

Incidence and extent of venous sequelae with intravenous diazepam utilizing a standardized conscious sedation technique.

Twenty-four periodontal patients volunteered for a study designed to investigate the incidence of venous sequelae with Injectable Valium administered by a standardized conscious sedation technique. Sedative doses were injected into veins on the dorsum of the hand utilizing a continuous infusion drip of 5% dextrose in water. Postoperative evaluation extended over 12 weeks. Ultrasonic tests for thrombosis were performed with a Doppler Flowmeter. Independent variables considered included age, vein size, volume of drug, volume of intravenous solution, pain upon injection and initial venous flow velocity. Sixteen subjects (66.67%) experienced some form of venous sequelae. Thirteen sequelae advanced to thrombophlebitis. Those subjects who demonstrated no complications had significantly higher initial venous flow than those with complications. Those subjects with resolution of complications demonstrated a significantly greater initial venous flow than those without resolution of complications. Clinical variables of pain on injection, vein diameter, dose of diazepam and volume of infusion solution did not significantly differ across groups. However, those subjects with no complications were significantly older than those with complications. It is recommended that the larger veins of the forearm and antecubital fossa, with greater mean velocities of venous flow, be preferred for intravenous diazepam administration to attempt to decrease the nature and incidence of thrombophlebitis.

Electromyographic analysis of the "baccinator mechanism" in human beings.

Electromyography of the muscles of the "buccinator mechanism" was undertaken, utilizing indwelling fine-wire electrodes. Electromyograms were made of 14 subjects with normal occlusion during various oral activities. Several activities elicited simultaneous contraction of all muscles. Simultaneous activity represents a potential restraining force of this muscular band on the dentition.

Oral factitious injuries.

The subject of oral factitious injuries is reviewed and four cases are reported. It is noted that self-inflicted oral injuries are not limited to the soft tissue but may result in destruction of bone and tooth structure. While children are more often the subjects of self-injurious behavior about the oral cavity, adults may also exhibit similar conduct. Emotional problems are often co-existent with self-inflicted oral injuries, however, in some cases there does not seem to be a readily descernible emotional disturbance. Since factitious injuries often pose diagnostic problems for the dentist, some diagnostic suggestions are included.