Anaesthetic efficacy of bupivacaine 2-hydroxypropyl-ß-cyclodextrin for dental anaesthesia after inferior alveolar nerve block in rats.

Bupivacaine is a long-acting local anaesthetic that is widely used in medicine and dentistry. The duration and intensity of its sensory blockade in animal models is increased by its inclusion in complexes with cyclodextrins. The aim of the present study was to evaluate the anaesthetic efficacy of bupivacaine 2-hydroxypropyl-ß-cyclodextrin (HPßCD) inclusion complex for dental anaesthesia after inferior alveolar nerve block in rats. Thirty rats were each given an injection close to the mandibular foramen of 0.2ml of one of the following formulations: 0.5% bupivacaine alone; 0.5% bupivacaine with 1:200,000 epinephrine; and 0.5% bupivacaine-HPßCD inclusion complex (bupivacaine-HPßCD). The other sides were used as controls, with either 0.9% saline or anaesthetic-free HPßCD solution being injected. The onset, success, and duration of pulpal anaesthesia were assessed by electrical stimulation ("pulp tester") on inferior molars. Results were analysed using ANOVA (Tukey), log rank, and chi square tests (α=5%). There were no differences among the formulations in onset of anaesthesia (p=0.59) or between the bupivacaine plus epinephrine and bupivacaine plus HPßCD in duration of anaesthesia, but bupivacaine plus epinephrine gave significantly higher values than bupivacaine alone (p=0.007). Bupivacaine plus epinephrine was a better anaesthetic than bupivacaine alone (p=0.02), while Bupi-HPßCD gave intermediate results, and therefore did not differ significantly from the other 2 groups (p=0.18 with bupivacaine alone; and p=0.44 with bupivacaine plus epinephrine). The bupivacaine-HPßCD complex showed similar anaesthetic properties to those of bupivacaine with epinephrine.

Medial orbital wall fractures: classification and clinical profile.

This article reports our experience and proposes a clinical classification regarding medial orbital wall fractures. After a retrospective analysis of 2741 patients with facial fractures, we were able to evaluate 273 patients with 304 medial orbital wall fractures. The male-to-female ratio was 5:1, and most injuries involved the left orbit. Most fractures were caused by personal altercations, but more complex injuries were noted with automobile accidents and falls. Fractures were divided into types based on location and severity of injury: type I (confined to the medial orbital wall), type II (medial orbital wall continuous with floor), type III (medial orbital wall with floor-malar fractures), and type IV (medial orbital wall and complex midfacial injuries). Although visual loss (2%), diplopia (41%), and enophthalmos (12%) were seen, diplopia and enophthalmos were commonly observed with type II injuries. Imaging studies showed that about 52% of the fractures were associated with prolapse of orbital fat, but only 43% could be diagnosed with plain x rays. Type I fractures were generally explored through a frontoethmoid incision; other types were treated with subciliary or transconjunctival approaches. The usual treatment consisted of repositioning the fragments and repair of the wall with polyethylene mesh or cranial bone graft. Type I and type II fractures seemed best explained by the hydraulic mechanism of injury, whereas the type III and type IV fractures best fitted the buckling theory.