Evaluation of four instruments with different working motion using artificial plastic model with C-shaped single canal.

The purpose of this study was to evaluate four instruments with different working motion for preparation of a C-shaped single canal wall using the same artificial plastic models reproduced from a human tooth. One tooth with root canal morphology C1 (the shape is an uninterrupted "C" with no separation or division) was selected among three-dimensional micro-computed tomography (micro-CT) imaging data of extracted human teeth. Imaging data were then converted into STL form data, and twenty-four C-shaped root canal model blocks were manufactured using this STL form data.

Removal of root canal filling materials using Er:YAG laser irradiation.

The purpose of this study was to examine the ability of Er:YAG laser to remove root canal filling materials. The root canals of 21 extracted human anterior teeth were enlarged, and then obturated with gutta-percha points and sealer by lateral condensation. Filling materials were removed from root canals using Er:YAG laser irradiation at three energy output levels (30, 40, and 50 mJ/ pulse), and the corresponding time required for material removal at each energy output level was recorded.

Energy output reduction and surface alteration of quartz and sapphire tips following Er:YAG laser contact irradiation for tooth enamel ablation.

Background: Despite the recent increase in application of Er:YAG laser for various dental treatments, limited information is available regarding the contact tips. This study examined the changes in energy output and surface condition of quartz and sapphire contact tips after Er:YAG laser contact irradiation for tooth enamel ablation.

Materials And Methods: Ten sets of unused quartz or sapphire contact tips were employed for contact irradiation to sound enamel of extracted teeth.

Clinical investigation of patients who develop neuropathic tooth pain after endodontic procedures.

Introduction: This study aimed to determine the characteristics of patients with neuropathic tooth pain (NTP) who were selected from a group of patients who developed persistent pain after undergoing endodontic procedures.

Methods: Of 271 patients who had chronic persistent pain that did not respond to previous endodontic procedures and were referred to the Endodontic Team of the Nippon Dental University Hospital, 16 patients (5.9%; mean age, 46.

Setting properties and sealing ability of hydraulic temporary sealing materials.

This study sought to investigate the setting progress and sealing ability of hydraulic temporary sealing materials used in endodontic treatment: Lumicon, Caviton, and HY-Seal. To evaluate setting progress, the materials were filled into glass tubes with one end sealed and immersed in water. After immersion, a measurement apparatus was inserted from the non-immersed end and the set area was determined by subtracting the unset area from the sample thickness.

Association of odor from infected root canal analyzed by an electronic nose with isolated bacteria.

Infected root canals usually cause foul odor. On sensory testing, objective evaluation of the odor is difficult because of the subjectivity of the examiner. In this study, the odor of the canal content was analyzed by an electronic nose.

Tooth-pulp-evoked rostral spinal trigeminal neuronal excitation is attenuated by the activation of 5-HT3 receptors via GABAergic interneurons in the rat.

The effect of iontophoretic application of the 5-HT3 receptor agonist, phenylbiguanide (PBG), on the excitation of the trigeminal spinal nucleus oralis (TSNO) neurons to tooth-pulp (TP) stimulation was examined. The PBG application inhibited the TP-evoked TSNO neuronal excitation, and this inhibition was completely blocked by co-application of a GABAA receptor antagonist, bicuculline. The results suggest that the activation of 5-HT3 receptors elicits GABA release in the TSNO.

Differential expression and localization of WNTs in an animal model of skin wound healing.

Wound healing is a dynamic process, and a variety of growth factors have a significant impact on the process. Although the WNT family has a multitude of effects on the state of various physiological pathways, the expression and role of WNT in wounded tissue have remained an enigma. The aim of this study was to assess the expression and localization of WNTs in a murine model of wound healing.

Tooth-pulp-evoked rostral spinal trigeminal nucleus neuron activity is inhibited by conditioning sciatic nerve stimulation in the rat: possible role of 5-HT3 receptor mediated GABAergic inhibition.

The purpose of the present study was to determine whether modulation of the trigeminal spinal nucleus oralis (TSNO) neurons related to tooth-pulp (TP)-evoked jaw-opening reflex (JOR) after electrical stimulation of the sciatic nerve (SN) is mediated by the descending serotonergic (5-HT(3)) inhibitory system activated by inhibitory GABAergic interneurons. In 30 anesthetized rats, the activity of TSNO neurons (87.5%, 35/40) and all digastric muscle electromyograms (dEMG, n=30) in response to TP stimulation (at an intensity of 3.

Electron probe micro-analysis of a contact probe after Er:YAG laser tooth ablation.

The purpose of this study was to investigate the contact probes of Er:YAG laser before and after tooth ablation. Three kinds of contact probe were prepared. The first was an unused probe (NE).

Adhesion of Er:YAG laser-irradiated dentin and composite resins: application of various treatments on irradiated surface.

Background And Objectives: The investigation of adhesion between an Er:YAG laser-irradiated surface and composite resin is very important to ensure the best clinical results. The purpose of this investigation is to determine if the application of various treatments on Er:YAG laser-irradiated dentin surface affects the tensile bond strength between dentin and composite resins.

Study Design/materials And Methods: In this investigation, the application of phosphoric acid, ultrasonic scaler, air-scaler, and air-powder polisher were tested as techniques to increase the bond strength of composite resins to Er:YAG laser-irradiated dentin surface.