Comparison of the Anesthetic Efficacy between Bupivacaine and Lidocaine in Patients with Irreversible Pulpitis of Mandibular Molar

Introduction: The purpose of this study was to compare the anesthetic efficacy of 0.5% bupivacaine with 1:200,000 epinephrine with that of 2% lidocaine with 1:100,000 epinephrine during pulpectomy in patients with irreversible pulpitis in mandibular posterior teeth. Methods: Seventy volunteers, patients with irreversible pulpitis admitted to the Emergency Center of the School of Dentistry at the University of Sao Paulo, randomly received a conventional inferior alveolar nerve block containing 3.6 mL of either 0.5% bupivacaine with 1:200,000 epinephrine or 2% lidocaine with 1:100,000 epinephrine. During the subsequent pulpectomy, we recorded the patients subjective assessments of lip anesthesia, the absence/presence of pulpal anesthesia through electric pulp stimulation, and the absence/presence of pain through a verbal analog scale. Results: All patients reported lip anesthesia after the application of either inferior alveolar nerve block. By measuring pulpal anesthesia success with the pulp tester, lidocaine had a higher success rate (42.9%) than bupivacaine (20%). For patients reporting none or mild pain during pulpectomy, the success rate of bupivacaine was 80% and lidocaine was 62.9%. There were only statistically significant differences to the success of pulpal anesthesia. Conclusions: Neither of the solutions resulted in an effective pain control during irreversible pulpitis treatments of mandibular molars. (J Endod 2012;38:594-597)

Neuropeptide Y in Rat Spiral Ganglion Neurons and Inner Hair Cells of Organ of Corti and Effects of a Nontraumatic Acoustic Stimulation

Neuropeptide Y (NPY) is an important neuromodulator found in central and peripheral neurons. NPY was investigated in the peripheral auditory pathway of conventional housed rats and after nontraumatic sound stimulation in order to localize the molecule and also to describe its response to sound stimulus. Rats from the stimulation experiment were housed in monitored sound-proofed rooms. Stimulated animals received sound stimuli (pure tone bursts of 8 kHz, 50 ms duration presented at a rate of 2 per second) at an intensity of 80 dB sound pressure level for 1 hr per day during 7 days. After euthanizing, rat cochleae were processed for one-color immunohistochemistry. The NPY immunoreactivity was detected in inner hair cells (IHC) and also in pillar and Deiters` cells of organ of Corti, and in the spiral ganglion putative type I (1,009 m3) and type II (225 m3) neurons. Outer hair cells (OHC) showed light immunoreaction product. Quantitative microdensitometry showed strong and moderate immunoreactions in IHC and spiral ganglion neurons, respectively, without differences among cochlear turns. One week of acoustic stimulation was not able to induce changes in the NPY immunoreactivity intensity in the IHC of cochlea. However, stimulated rats showed an overall increase in the number of putative type I and type II NPY immunoreactive spiral ganglion neurons with strong, moderate, and weak immunolabeling. Localization and responses of NPY to acoustic stimulus suggest an involvement of the neuropeptide in the neuromodulation of afferent transmission in the rat peripheral auditory pathway.

Short dental implants in posterior mandible

The rehabilitation with oral implants is, without any doubt, a consecrated technique. But often we face situations of high bone atrophy where the conventional installation of dental implants is not possible. The posterior mandible, when severely resorbed, generally requires complex techniques to be rehabilitated with implants, such as the lateralization of the inferior alveolar nerve. As an option for these cases, this paper proposes the use of short implants for the rehabilitation of severely resorbed posterior mandible. Copyright © 2013 by Mutaz B. Habal, MD.

Use of straight and curved 3-dimensional titanium miniplates for fracture fixation at the mandibular angle

PURPOSE: The aim of this follow-up study was to evaluate the clinical usefulness of a new type of 3-dimensional (3D) miniplate for open reduction and monocortical fixation of mandibular angle fractures. PATIENTS AND METHODS: In 20 consecutive patients, noncomminuted mandibular angle fractures were treated with open reduction and fixation using a 2 mm 3D miniplate system in a transoral approach. All patients were systematically monitored until 6 months postoperatively. Among the outcome parameters recorded were infection, hardware failure, wound dehiscence, and sensory disturbance of the inferior alveolar nerve. RESULTS: The mean operation time from incision to wound closure was 65 minutes. Two patients had a mucosal wound dehiscence with no consequences. None developed an infection requiring a plate removal. All but 2 patients had normal sensory function 3 months after surgery. Plate fracture occurred in one patient in whom a preceding surgical removal of the third molar had been the reason for the mandibular fracture. In the absence of clinical symptoms, the patient declined plate removal. On final follow-up, fracture healing was considered clinically complete in all patients. CONCLUSIONS: The 3D plating system described here is suitable for fixation of simple mandibular angle fractures and is an easy-to-use alternative to conventional miniplates. The system may be contraindicated in patients in whom insufficient interfragmentary bone contact causes minor stability of the fracture.

Efficacy of panoramic radiographs in the preoperative planning of posterior mandibular implants: a prospective clinical study of 1527 consecutively treated patients

OBJECTIVES: Various imaging techniques, including conventional radiography and computed tomography, are proposed to localize the mandibular canal prior to implant surgery. The aim of this study is to determine the incidence of altered mental nerve sensation after implant placement in the posterior segment of the mandible when a panoramic radiograph is the only preoperative imaging technique used. MATERIAL AND METHODS: The study included 1527 partially and totally edentulous patients who had consecutively received 2584 implants in the posterior segment of the mandible. Preoperative bone height was evaluated from the top of the alveolar crest to the superior border of the mandibular canal on a standard panoramic radiograph. A graduated implant scale from the implant manufacturer was used and 2 mm were subtracted as a safety margin to determine the length of the implant to be inserted. RESULTS: No permanent sensory disturbances of the inferior alveolar nerve were observed. There were two cases of postoperative paresthesia, representing 2/2584 (0.08%) of implants inserted in the posterior segment of the mandible or 2/1527 (0.13%) of patients. These sensory disturbances were minor, lasted for 3 and 6 weeks and resolved spontaneously. CONCLUSIONS: Panoramic examination can be considered a safe preoperative evaluation procedure for routine posterior mandibular implant placement. Panoramic radiography is a quick, simple, low-cost and low-dose presurgical diagnostic tool. When a safety margin of at least 2 mm above the mandibular canal is respected, panoramic radiography appears to be sufficient to evaluate available bone height prior to insertion of posterior mandibular implants; cross-sectional imaging techniques may not be necessary.

Computer-aided operation planning and 3-dimensional osteotomy guidance for alveolar distraction

Objectives: In alveolar distraction, in cases of severe atrophy in particular, it is often difficult to perform osteotomies in order to make a transport segment in optimal size and shape. Moreover care must be taken, not to damage the closely locating anato- mical structures such as the maxillary sinus, the inferior alveolar nerve, and the roots of the neighboring teeth. For setting ideal osteotomy lines exactly, we have developed a CT-based preoperative planning tool. Methods: 3-dimensional visual reconstruction of the jaw is created from the preoperative CT scans (1.0-mm slice thick- ness). Using the image-processing software Mimics (Materialise, Yokohama, Japan), various procedures of virtual cutting are simulated first to determine optimal osteotomy lines and to design an ideal transport segment. After the computer planning, data from the virtual solid model are transferred to a rapid prototype model, and a guiding splint is made to transfer the planned surgical simulation to the actual surgery. Results: The method was used in a case of severe atrophy of the anterior maxilla. The patient had a large maxillary sinus requir- ing a precise osteotomy in this critical area. Using the splint allowing a 3-dimensional guidance, alveolar osteotomies were easily done to achieve a transport segment in sufficient dimen- sion as planned, and any perforation of the maxillary sinus could be avoided. Finally the alveolar distraction of 10mm has suc- cessfully been performed. Conclusion: The preoperative planning method and the guiding splint described here are useful in problematic cases requiring an extremely precise osteotomy due to lack of bony space.

A Novel Approach to Intraoral Mandibular Nerve Anesthesia: Changing Reference Planes in the Gow-Gates Block Technique

Purpose: The Gow-Gates technique is said to have several advantages over traditional techniques to achieve mandibular nerve anesthesia; however, its routine use is quite limited, mainly due to complications during visual alignment of reference landmarks. The purpose of this study was to verify the validity and accuracy of a new method to reach the injection site. Material and Methods: Fifteen magnetic resonance images were captured. Distances from the ideal injection point in the condylar neck (puncture ideal) to the injection points located in the a and 0 plane intersection (Puncture Gow-Gates and puncture modified) were measured and compared. Results: Positive and significant (P <= .003) Pearson correlations between landmarks and injection points confirmed the validity of the modified technique. Paired t test showed that the segment line puncture ideal-puncture modified, 5.17 mm, was 3 times shorter (P < .001) than the segment line puncture ideal-puncture Gow-Gates, 17.91 mm. As calculated by linear regression, establishing the injection point of the modified technique depended only on the anteroposterior and lateromedial condyle positions. Conclusions: The modified technique proved to be valid and precise and has a determined and an effective injection site. (C) 2009 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 67:2609-2616, 2009

Eruption Cysts in the Neonate

Disturbances of the dental development may result in anomalies, which may be apparent as soon as the child is born. Eruption cysts are rarely observed in neonates considering that at this stage of the child`s life teeth eruption is uncommon. Thus, the aim of this report is to describe a case of eruption cysts in a neonate. A male neonate was brought to the emergency service with the chief complaint of an elevated area on the anterior region of the inferior alveolar ridge. The lesion was clinically characterized as a compressive and floating swelling. Through a radiographic exam two mandibular primary incisors could be seen superficially located. Due to the patient`s age and the initial diagnosis of eruption cysts the conduct adopted was clinical surveillance. Forty-five days after the first visit the lesions had significantly decreased in size, and completely disappeared after 4 months. at that age, both mandibular central incisors were already in the oral cavity exhibiting small hypoplastic areas in the incisal edges. The clinical and radiographic follow-up of eruption cysts in neonates appears to be an adequate conduct without differing from that recommended for older children.

Trigeminal nitric oxide synthase expression correlates with new bone formation during distraction osteogenesis

Nitric oxide synthase (NOS) has been reported to be involved with both bone healing and bone metabolism. The aim of this study was to test the null hypothesis that there is no correlation between new bone formation during mandibular distraction osteogenesis and NOS expression in the trigeminal ganglion of rats. Newly formed tissue during distraction osteogenesis and trigeminal NOS expression measured by the NADPH-diaphorase (NADPH-d) reaction were evaluated in 72 male Wistar rats by histomorphometric and histochemical methods. In animals submitted to 0.5 mm/day distraction osteogenesis, the percentage of bone tissue was higher in the basal area of the mandibles compared with the center and significantly increased through the experimental periods (P < 0.05). At the sixth postoperative week, the difference in bone formation between the continuous and acute distraction osteogenesis groups was the highest. Significant correlation between new bone formation by distraction osteogenesis and NADPH-d-reactive neurons was found, varying according to neuronal cell size (r = -0.6, P = 0.005, small cells strongly stained; r = 0.5, P = 0.018, large cells moderately stained). The results suggest that NOS may play a role in the bone healing process via neurogenic pathways, and the phenomenon seems to be neuronal cell morphotype-dependent. Further studies are now warranted to investigate the mechanistic link between the expression of trigeminal NOS and mandibular new bone formation by distraction osteogenesis.

Use of Rectangular Grid Miniplates for Fracture Fixation at the Mandibular Angle

Purpose: The aim of this study was to evaluate the clinical outcome of patients with mandibular angle fractures treated by intraoral access and a rectangular grid miniplate with 4 holes and stabilized with monocortical screws.Patients and Methods: This study included 45 patients with mandibular angle fractures from the Department of Oral and Maxillofacial Surgery São Paulo State University, Araraquara, Brazil, and from the Clinic of Oral and Maxillofacial Surgery at the University of Frankfurt, Germany. The 45 fractures of the mandibular angle were treated with a rectangular grid miniplate of a 2.0-mm system by an intraoral approach with monocortical screws. Clinical evaluations were postoperatively performed at 15 and 30 days and 3 and 6 months, and the complications encountered were recorded and treated.Results: The infection rate was 4.44% (2 patients), and in 1 patient it was necessary to replace hardware. This patient also had a fracture of the left mandibular body; 3 patients (6.66%) had minor occlusal changes that have been resolved with small occlusal adjustments. Before surgery, 15 patients (33.33%) presented with hypoesthesia of the inferior alveolar nerve; 4 (8.88%) had this change until the last clinical control, at 6 months.Conclusions: The rectangular grid miniplate used in this study was stable for the treatment of simple mandibular angle fractures through intraoral access, with low complication rates, easy handling, and easy adjustment, with a low cost. Concomitant mandibular fracture may increase the rate of complications. This plate should be indicated in fractures with sufficient interfragmentaty contact. (C) 2011 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 69:1436-1441, 2011

Clinical significance of supplementary innervation of the lower incisor teeth: a dissection study of the myelohyoid nerve

In view of the relevance of the mylohyoid nerve to clinical difficulties in achieving deep analgesia of the lower incisors, a dissection study was undertaken. Dissections from 29 adult cadavers of both sexes were studied with the aid of a dissecting microscope. The following observations were made: a supplementary branch of the mylohyoid nerve entered the mandible through accessory foramina in the lingual side of the mandibular symphysis in 50% of the cases; it generrally arose from the right side (76.9%) and entered the inferior retromental foramen (84.6%); the mylohyoid nerve branch either ended directly in the incisor teeth and the gingiva or joined the ipsilateral or contralateral incisive nerve. In view of this information concerning the high incidence of possible involvement of the mylohyoid nerve in mandibular sensory innervation, it is advisable to block it whenever intervention in the lower incisors is indicated. Routine mylohyoid injection is recommended after mental nerve block. If the inferior alveolar nerve is chosen for anesthetic purposes, additional mylohyoid injection should be given only if pain persists. The mylohyoid injection should be given at the inferior retromental foramen on the median aspect of the inferior border of the mandible through extraoral approach.

Paresthesia during orthodontic treatment: case report and review.

Paresthesia of the lower lip is uncommon during orthodontic treatment. In the present case, paresthesia occurred during orthodontic leveling of an extruded mandibular left second molar. It was decided to remove this tooth from the appliance and allow it to relapse. A reanatomization was then performed by grinding. The causes and treatment options of this rare disorder are reviewed and discussed. The main cause of paresthesia during orthodontic treatment may be associated with contact between the dental roots and inferior alveolar nerve, which may be well observed on tomography scans. Treatment usually involves tooth movement in the opposite direction of the cause of the disorder.

Prospective study of postoperative sensory disturbances after surgical treatment of mandibular fractures

Introduction: This present study's purpose is to evaluate the degree of paresthesia and recovery of inferior alveolar nerve in patients with mandible fractures who underwent surgical treatment. Material and methods: Nineteen patients were evaluated (27 hemimandibles) at six different times: preoperative (T1), postoperative 1 week (T2), postoperative 1 month (T3), postoperative 3 months (T4), postoperative 6 months (T5), and postoperative 1 year (T6). Subjective and objective methods were used for this evaluation. Results: The results were analyzed using likelihood ratio chi-square test for the hypothesis of no association between indicators of sensitivity and responses to the questionnaire, and the Cochran-Mantel-Haenszel test for equality hypothesis. All objective tests showed a statistically significant worsening in sensitivity at T2 (p < 0. 0001) and a significant improvement after T4 (α < 0. 05). The subjective tests showed an association with the objectives tests, and improvement in sensitivity after T4 (p < 0. 0001) was noted. Discussion: The first postoperative week is the period in which there are major changes with respect to sensitivity, and after 3 months postoperatively, the recovery reaches its apex with little difference observed after this period. In this research 100 % of the patients analyzed recovered all sensibility until T6. © 2012 Springer-Verlag.

Sagittal Mandibular Osteotomy for Removal of Intraosseous Lesion

The ramus sagittal split osteotomy or mandibular body is an established technique for correction of dentofacial deformities but can have an accurate indication in cases requiring surgical access to remove lesions or more teeth included in the region of the mandibular angle. The main advantages of this technique are the possibility of preservation of the inferior alveolar nerve bundle and significant reduction in postoperative morbidity. In this article, the authors show a case in which the sagittal osteotomy of the mandible was used to gain access for removal of a lesion (complex odontoma).

Cutaneous sensibility impairmentafter mandibular sagittal split osteotomy: a prospective clinical study of the spontaneous recovery

Purpose The aim of this prospective study was to objectively evaluate the inferior alveolar nerve (IAN) sensory disturbances in patients who underwent sagittal split ramus osteotomy (SSRO) and its spontaneous recovery and to define the incidence of sensibility loss, time, and area at which the recovery occurs. Patients and Methods Clinical evaluation of the IAN sensory disturbance was undertaken preoperatively and at the first week, fourth week, 2 months, and 6 months postoperatively in 30 patients who underwent SSRO at the Oral and Maxillofacial Surgery Division of the Araraquara Dental School--Unesp and at the Plastic Surgery Division of the Medical Sciences School--Unicamp. The 30 patients were examined at all periods regarding the IAN functionality by Semmes-Weinstein testing. Results The mean age of the patients included in this study was 29.36 years old. All patients showed sensibility loss at the 7-day evaluation time. The comparison between sides, gender, and age did not show any significant difference. In most of the examined zone, the data collected at 6 months were statistically similar to the data collected at the preoperative period. All zones presented significant recovery, starting from 30 days after surgery. Twenty patients had total spontaneous recovery at the final period, in all examined zones. Conclusions The SSRO presents the disadvantage of temporary paresthesia; however, spontaneous nerve function recovery does occur. The Semmes-Weinstein test is a reliable, inexpensive, and easy-to-apply tool, which can be used for clinical evaluation on a daily basis at offices and hospitals.