Development of resurgent and persistent sodium currents in mesencephalic trigeminal neurons.

Sodium channels play multiple roles in the formation of neural membrane properties in mesencephalic trigeminal (Mes V) neurons and in other neural systems. Mes V neurons exhibit conditional robust high-frequency spike discharges. As previously reported, resurgent and persistent sodium currents (I and I , respectively) may carry small currents at subthreshold voltages that contribute to generation of spike firing.

Asymmetric Anterior Distraction for Transversely Distorted Maxilla and Midfacial Anteroposterior Deficiency in a Patient With Cleft Lip/Palate: Two-Stage Surgical Approach.

The present report describes a male patient with a unilateral cleft lip and palate who presented with midfacial anteroposterior and transverse deficiency. Correction involved a two-stage surgical-orthodontic approach: asymmetric anterior distraction of the segmented maxilla followed by two-jaw surgery (LeFort I and bilateral sagittal splitting ramus osteotomies). The present case demonstrates that the asymmetric elongation of the maxilla with anterior distraction is an effective way to correct a transversely distorted alveolar form and midfacial anteroposterior deficiency.

Protein kinase A regulates the long-term potentiation of intrinsic excitability in neonatal trigeminal motoneurons.

Although much is known about neuronal plasticity in the mammalian hippocampus and other cortical neurons, the subcellular mechanisms underlying plasticity at the level of motor pools are less well characterized. Protein kinase A (PKA) activation plays an essential role in long-term potentiation of intrinsic excitability (LTP-IE) in layer V (LV) visual cortical neurons and may be involved in other systems as well. Trigeminal motoneurons (TMNs) participate in rhythmical motor behaviors, such as suckling, chewing, and swallowing.

Role of endothelin receptor signalling in squamous cell carcinoma.

Endothelin plays important roles in various physiological functions including vascular constriction. Recent studies reported that the endothelin receptors ETA and ETB are highly expressed in lung and skin tumor tissues. In contrast, there are few reports on endothelin signalling in the proliferation of head and neck cancer.

Aerial dispersal of blood-contaminated aerosols during dental procedures.

Objectives: Dental procedures with high-speed instruments produce large amounts of aerosols. The present study aimed to clarify whether blood-contaminated aerosols were existent and floating in air during dental procedures and to evaluate the effect of an extraoral evacuator system.

Method And Materials: An extraoral evacuator system with a test filter was used for sample collection at distances from 50 cm (n = 102) and 100 cm (n =124) behind the patient.

Inferior alveolar nerve canal and branches detected with dental cone beam computed tomography in lower third molar region.

Purpose: To evaluate the course of the inferior alveolar nerve and its branches, the detectable branches were investigated with dental cone beam computed tomography (CBCT).

Materials And Methods: Patients in whom the lower third molar (M3) and inferior alveolar nerve canal showed overlapping in the initial panoramic image were included. One hundred twelve impacted lower M3s were extracted after examination with dental CBCT.

Floating aerial blood mists in the operating room.

High-speed surgical instruments and electric coagulator devices produce contaminated particles and aerosols. This study aimed to investigate the presence of blood-contaminated aerosol in a class 6 and 7 (ISO14644-1) operating room environment. Test filters were fitted to the extract ducts of a standard central air conditioning system, and were left in place for 1, 2, or 4 weeks.

Bone formation without lamina dura in the middle-aged and elderly: possible dependence on enamel.

Bone formation below the crown of mandibular horizontal incompletely impacted third molar is frequently seen in the middle-aged and elderly. The phenomenon shows lamina dura loss without radiolucency and we hypothesized the participation of mature enamel without any influence on the environmental oral status. In order to investigate the characteristics of the phenomenon based on the presence/absence of the lamina dura and radiolucency below the crown, we studied the relationship between 58 men and 43 women with a lamina dura without radiolucency, 12 men and 8 women without a lamina dura with radiolucency, 34 men and 16 women without a lamina dura without radiolucency, and the status of teeth in the ipsilateral mandible.

A comparison of the postnatal development of muscle-spindle and periodontal-ligament neurons in the mesencephalic trigeminal nucleus of the rat.

The trigeminal mesencephalic nucleus (Vmes) is known to include primary afferent neurons of jaw muscle spindles (MS neurons) and periodontal ligament receptors (PL neurons). The aim of this study was to clarify the postnatal development of Vmes neurons by comparing MS neurons with PL neurons using horseradish peroxidase labeling. We measured somal diameter and somal shape of MS and PL neurons in rats from postnatal day (P)7 to P70.

Occupational safety among dental health-care workers.

Compared to other health-care workers, dental health-care workers come in close contact with patients and use a variety of sharp and high-speed rotating instruments. It is important to understand the characteristics of the occupational accidents that occur. We reviewed incident reports from April 1, 2005, to March 31, 2010, at Matsumoto Dental University Hospital.

Age-related disruption of the lamina dura: evidence in the mandibular horizontal incompletely impacted third molar.

Changes in the lamina dura are associated with dental diseases around the root of the tooth and with systemic diseases; however, the lamina dura below the crown of horizontal, incompletely impacted third molars has not been studied. Using orthopantomography, we studied the age of subjects with and without the lamina dura in 419 subjects. The participants were between the ages of 21 and 89 years.

Long-term potentiation of intrinsic excitability in trigeminal motoneurons.

Trigeminal motoneurons (TMNs) relay the final output signals generated within the oral-motor pattern-generating circuits to the jaw muscles for execution of various patterns of motor activity. Activity-dependent plasticity, referred to as long-term potentiation (LTP), in the central nervous system has been the subject of many studies. The mechanisms of plasticity in the trigeminal system, an important component of the oral-motor system underlying mastication, swallowing, and other behaviors, remain to be fully elucidated.

High incidence of blood exposure due to imperceptible contaminated splatters during oral surgery.

Purpose: To evaluate the incidence of blood exposure during outpatient oral surgery from splattering caused by use of high-speed rotary instruments at the Referral and Teaching Center, University Dental Hospital.

Materials And Methods: Twenty-five consecutive patients who had impacted mandibular third molars were selected. The attending surgeon wore an operation gown and visor mask, and carried out the tooth extraction with the regular procedure.

Possible involvement of neurons in locus coeruleus in inhibitory effect on glossopharyngeal expiratory activity in a neonatal rat brainstem-spinal cord preparation in vitro.

In this study, we found that a certain motor branch of glossopharyngeal (IX) motor nerves stably exhibits not only inspiratory activity but also expiratory activity with pons removal in neonatal rat brainstem-spinal cord preparations in vitro. Because this finding indicates that IX expiratory activity is masked by an inhibitory mechanism operating in the pons, we sought to determine the candidate neurons that exert an inhibitory effect on IX expiratory activity. IX expiratory activity was observed when only the pons was perfused with noradrenaline (NA) or clonidine (alpha2 adrenergic receptor agonist), but not when NA and yohimbine (alpha2 adrenergic receptor antagonist) were perfused together.

Comparison of surgical and nonsurgical treatment of bilateral condylar fractures based on maximal mouth opening.

This study presents a comparative analysis of the open surgical and nonsurgical treatment of patients with bilateral condylar fractures. Sixty-seven (67) patients were treated, and the completed data on 55 patients were reviewed to compare both therapeutic modalities, which consisted of nonsurgical and surgical treatment in 37 and 18 patients, respectively. In the nonsurgical group, 23 patients (23/37, 62%) had normal mouth opening.

NR3 protein expression in trigeminal neurons during postnatal development.

The N-methyl-d-aspartate (NMDA) receptor plays an important role in the generation of rhythmical oral motor activities. To compliment our previous studies, we examined the developmental regulation of NR3A and NR3B expression in trigeminal motoneurons (Mo5) and mesencephalic trigeminal neurons (Me5). NR3A-immunoreactive neurons were observed at all ages in both nuclei, decreasing in Mo5 and caudal Me5 after P14, and increasing in rostral Me5.

Azithromycin as prophylaxis for the prevention of postoperative infection in impacted mandibular third-molar surgery.

Rotational use of antimicrobials is one of the strategies that have been suggested to reduce the development of drug-resistant bacteria. Cycling of homogeneous antimicrobial exposure is, however, unlikely to control the emergence of antimicrobial resistance. Penicillins and cephalosporins have been extensively used for therapeutic and prophylactic management of oral infection.

Prenatal development of NMDA receptor composition and function in trigeminal neurons.

The prenatal development of neural circuits for rhythmical oral-motor behaviors used for feeding is essential for the survival of the newborn mammal. The N-methyl-D-aspartate (NMDA) receptor plays a critical role in brainstem circuits underlying postnatal oral-motor behaviors. To understand a role for the NMDA receptor in the emergence of sucking behavior we conducted physiological and immunohistochemical experiments using fetal rats.

Oral-motor patterns of rhythmic trigeminal activity generated in fetal rat brainstem in vitro.

Development of neural circuits generating fetal oral-motor activity was characterized in an in vitro isolated brainstem block preparation. Rhythmical trigeminal activity (RTA) at E20-E21 resembled either the pattern or rhythm of neonatal RTA. Conversely, at E18-E19, RTA displayed a different pattern of discharge from neonatal RTA, and output was not regular but intermittent with another slow rhythm.

Localization of premotoneurons for an NMDA-induced repetitive rhythmical activity to TMNs.

The localization or characteristics of the premotoneurons for trigeminal rhythmical activity have not been clarified. We investigated the localization of premotoneurons generating an NMDA-induced repetitive rhythmical activity to trigeminal motoneurons (TMNs). The minimal circuitry for this rhythmical activity was determined using a fragmented slice preparation of the isolated brain stem from neonatal rats (0-3 days old).

Differential discharge patterns of rhythmical activity in trigeminal motoneurons during fictive mastication and respiration in vitro.

Rhythmical activity in trigeminal motoneurons (TMNs) was studied in an in vitro neonatal rat brainstem preparation that retains functionally active circuits for oral-motor behaviors. Whole-cell current-clamp recording from TMNs demonstrated rhythmical activities during both spontaneously generated respiratory activity and neurochemically induced rhythmical oral-motor activity. TMNs showed spontaneous rhythmical (0.