BACKGROUND: Dental injury is well-recognized as a potential complication of laryngoscopy and tracheal intubation. However, the frequency, outcomes, and risk factors for this problem have not been documented in a well-defined patient population. METHODS: The authors analyzed the dental injuries of 598,904 consecutive cases performed on patients who required anesthetic services from 1987 through 1997. Dental injuries were defined as perianesthetic events (those occurring within 7 days) that required dental interventions to repair, stabilize, or extract involved dentition or support structures. A 1:3 case-control study of 16 patient and procedural characteristics was performed for cases that occurred during the first 5 yr of the study. Conditional logistic regression was used for data analysis. RESULTS: There were 132 cases (1:4,537 patients) of dental injury. One half of these injuries occurred during laryngoscopy and tracheal intubation. The upper incisors were the most commonly involved teeth, and most injuries were crown fractures and partial dislocations and dislodgements. Multivariate risk factors for dental injury in the case control study included general anesthesia with tracheal intubation (odds ratio [OR] = 89), preexisting poor dentition (OR = 50), and increased difficulty of laryngoscopy and intubation (OR = 11). CONCLUSIONS: Based on these data from a large surgical population at a single training institution, approximately 1:4,500 patients who receive anesthesia services sustain a dental injury that requires repair or extraction. Patients most at risk for perianesthetic dental injury include those with preexisting poor dentition who have one or more risk factors for difficult laryngoscopy and tracheal intubation. (+info)
(2/90) Dental injury models: experimental tools for understanding neuroinflammatory interactions and polymodal nociceptor functions.
Recent research has shown that peripheral mechanisms of pain are much more complex than previously thought, and they differ for acutely injured normal tissues compared with chronic inflammation or neuropathic (nerve injury) pain. The purpose of the present review is to describe uses of dental injury models as experimental tools for understanding the normal functions of polymodal nociceptive nerves in healthy tissues, their neuroinflammatory interactions, and their roles in healing. A brief review of normal dental innervation and its interactions with healthy pulp tissue will be presented first, as a framework for understanding the changes that occur after injury. Then, the different types of dental injury that allow gradation of the extent of tissue damage will be described, along with the degree and duration of inflammation, the types of reactions in the trigeminal ganglion and brainstem, and the type of healing. The dental injury models have some unique features compared with neuroinflammation paradigms that affect other peripheral tissues such as skin, viscera, and joints. Peripheral inflammation models can all be contrasted to nerve injury studies that produce a different kind of neuroplasticity and neuropathic pain. Each of these models provides different insights about the normal and pathologic functions of peripheral nerve fibers and their effects on tissue homeostasis, inflammation, and wound healing. The physical confinement of dental pulp and its innervation within the tooth, the high incidence of polymodal A-delta and C-fibers in pulp and dentin, and the somatotopic organization of the trigeminal ganglion provide some special advantages for experimental design when dental injury models are used for the study of neuroinflammatory interactions. (+info)
(3/90) Survey of dental treatments for pediatric patients referred to the pediatric dental clinic of a dental school hospital.
This survey was conducted to clarify which dental treatments in children are regarded as difficult by general dentistry practitioners. The subjects were 615 children who first visited Tokyo Dental College Chiba Hospital from January 1995 to August 1999 with reference letters. There were 615 children in the study; 571 (92.8%) came from Chiba City where our hospital is located and the 11 regions surrounding Chiba City. The prime reasons for referral in the order of frequency were treatments of dental caries, malalignment/malocclusion, traumatized teeth, supernumerary teeth, retarded eruption/impacted teeth, abnormal direction of erupted teeth, congenitally missing teeth, prolonged retention of deciduous teeth, and abnormal frenulum. Patients with dental caries or traumatized teeth in the deciduous dentition period and those with malalignment/malocclusion, supernumerary teeth, or retarded eruption/impacted teeth in the mixed dentition period were often referred to medical organizations specializing in pediatric dentistry because of the difficulties in controlling the patients' behavior and in providing adequate treatment. The information about pediatric dental treatments considered difficult by general dentists revealed by this survey appears to be useful and needs to be incorporated in the programs for clinical training of undergraduate students and education of postgraduate students. (+info)
(4/90) A radiographic comparison of apical root resorption after orthodontic treatment with a standard edgewise and a straight-wire edgewise technique.
The purpose of this study was to compare the severity of apical root resorption occurring in patients treated with a standard edgewise and a straight-wire edgewise technique, and to assess the influence of known risk factors on root resorption incident to orthodontic treatment. The sample consisted of 80 patients with Angle Class II division 1 malocclusions, treated with extraction of at least two maxillary first premolars. Variables recorded for each patient included gender, age, ANB angle, overjet, overbite, trauma, habits, invagination, agenesis, tooth shedding, treatment duration, use of Class II elastics, body-build, general factors, impacted canines, and root form deviation. Forty patients were treated with a standard edgewise and 40 with a straight-wire edgewise technique, both with 0.018-inch slot brackets. Crown and root lengths of the maxillary incisors were measured on pre- and post-treatment periapical radiographs corrected for image distortion. Percentage of root shortening and root length loss in millimetres were then calculated. There was significantly more apical root resorption (P < 0.05) of both central incisors in the standard than in the straight-wire edgewise group. No significant difference was found for the lateral incisors. Root shortening of the lateral incisors was significantly associated with age, agenesis, duration of contraction period (distalization of incisors), and invagination, while root shortening of the central incisors was related to treatment group and trauma. (+info)
(5/90) Transient forces generated by projectiles on variable quality mouthguards monitored by instrumented impact testing.
OBJECTIVES: (a) To determine the force-time trace that occurs when a spring mounted simulated upper jaw is impacted; (b) to examine if mouthguards of variable quality have significant influence on such force-time traces; (c) to attempt to relate physical events to the profile of the force-time traces recorded. METHODS: A simulated jaw, consisting of ceramic teeth inserted into a hard rubber arch reinforced with a composite jawbone, was fitted with various mouthguards as part of a previous round robin study. A clinical assessment distinguished good, bad, and poor mouthguards, and these were each fitted to the jaw, which was then submitted to instrumental impact tests under conditions expected to produce tooth fractures. The force-time trace was recorded for such impact events. RESULTS: The spring mounting method caused two distinct peaks in the force-time trace. The initial one was related to inertia effects and showed an increase in magnitude with impactor velocity as expected. The second peak showed features that were related to the differences in the mouthguards selected. CONCLUSIONS: The use of a force washer within a conical ended impactor enabled force-time traces to be recorded during the impact of a spring mounted simulated jaw fitted with mouthguards of variable quality. The spring mounting system causes an initial inertial peak followed by a second peak once the spring mount has fully compressed. Good fitting guards, which keep most teeth intact, result in high stiffness targets that in turn generate high reaction forces in the impactor. If the spring mounting is omitted, the two peaks are combined to give even higher reaction forces. The force-time trace offers some potential for assessing both overall mouthguard performance and individual events during the impact sequence. Mouthguards with good retention to the jaw remained attached during the impact event and helped to preserve the structural integrity of the target. This in turn developed high forces in the second part of the force-time trace. Guards that detached during impact and allowed tooth fractures showed lower forces in the second part of the test. The force profile measured offered some quantitative support to, and agreement with, the observed clinical quality of the mouthguards. (+info)
(6/90) E- and N-cadherin distribution in developing and functional human teeth under normal and pathological conditions.
Cadherins are calcium-dependent cell adhesion molecules involved in the regulation of various biological processes such as cell recognition, intercellular communication, cell fate, cell polarity, boundary formation, and morphogenesis. Although previous studies have shown E-cadherin expression during rodent or human odontogenesis, there is no equivalent study available on N-cadherin expression in dental tissues. Here we examined and compared the expression patterns of E- and N-cadherins in both embryonic and adult (healthy, injured, carious) human teeth. Both proteins were expressed in the developing teeth during the cap and bell stages. E-cadherin expression in dental epithelium followed an apical-coronal gradient that was opposite to that observed for N-cadherin. E-cadherin was distributed in proliferating cells of the inner and outer enamel epithelia but not in differentiated cells such as ameloblasts, whereas N-cadherin expression was up-regulated in differentiated epithelial cells. By contrast to E-cadherin, N-cadherin was also expressed in mesenchymal cells that differentiate into odontoblasts and produce the hard tissue matrix of dentin. Although N-cadherin was not detected in permanent intact teeth, it was re-expressed during dentin repair processes in odontoblasts surrounding carious or traumatic sites. Similarly, N-cadherin re-expression was seen in vitro, in cultured primary pulp cells that differentiate into odontoblast-like cells. Taken together these results suggest that E- and N-cadherins may play a role during human tooth development and, moreover, indicate that N-cadherin is important for odontoblast function in normal development and under pathological conditions. (+info)
(7/90) Involvement of the NMDA-nitric oxide pathway in the development of hypersensitivity to tactile stimulation in dental injured rats.
To investigate mechanisms in pathological pain conditions as the hyperalgesia and allodynia observed after dental surgery, we employed a rat dental-injury model involving the simultaneous pulpectomy to a lower incisor and extraction of an ipsilateral upper incisor. We found that hypersensitivity to tactile stimulation developed on both ipsilateral and contralateral sides in the dental-injured rats 5 days after the surgery and that this lasted for at least 30 days. Recovery from hypersensitivity to tactile stimulation was achieved by the intraperitoneal (i.p.) administration of MK-801 (0.05 mg/kg) or N(G)-monomethyl-L-arginine monoacetate (L-NMMA: 10 - 100 mg/kg), but not attained by N(G)-monomethyl-D-arginine monoacetate (D-NMMA: 100 mg/kg). This recovery effect of L-NMMA (50 mg/kg) was inhibited by pretreatment with L-arginine (600 mg/kg). In the trigeminal nucleus caudalis (SpVc), the changes in nitric oxide (NO) levels invoked by the intravenous (i.v.) administration of N-methyl-D-aspartate (NMDA; 10 mg/kg) were found to be significantly larger in the dental-injured rats than in sham-operated rats. The number of neuronal NO synthase (nNOS)-positive neurons increased in layers I-II and III-IV in the SpVc on both sides of the dental-injured rats. These results suggest that hypersensitivity to tactile stimulation developed following dental injury, and that NMDA receptor/NOS/NO production pathways in the SpVc may be involved in pathological conditions. (+info)
(8/90) The avoidability of head and neck injuries in ice hockey: an historical review.
The number of minor traumatic brain injury (mTBI), cerebral concussions, is increasing and cannot be eliminated by any kind of equipment. Prevention strategies, such as the introduction of "checking from behind" rules have become effective in decreasing the number of severe spinal injuries. A new "head checking" rule should reduce mTBI in the same way in the following years. Mouthguards should be mandatory as an effective device for the prevention of dental and orofacial injuries, as well as reducing the incidence and severity of mTBI. A new internet database system, the International Sports Injury System (ISIS) should improve epidemiological analysis of head, face, and spinal injuries worldwide. ISIS should provide an internationally compatible system for continuous monitoring of risk factors, protective effects of equipment, and protective effects of equipment and effects of changes in rules through the years. (+info)