[Evaluation of the effects of TF and S3 nickel-titanium instruments in severely curved molar root canal preparation].

Purspose: To compare the shaping ability and dental cracks of Twisted File and S3 in severely curved molar root canal preparation.

Methods: Sixty extracted mandibular molars with mesiobuccal canals (canal curvature angles beyond 25°) were selected and divided randomly into 2 groups with 30 canals in each group. The canals were scanned by cone-beam CT(CBCT) before and after root canal preparation .

A pilot study on transient ischemic stroke induced with endothelin-1 in the rhesus monkeys.

Endothelin-1 (ET-1), a vasoconstrictor, has recently been used to induce focal ischemia in rodents and marmoset monkeys. The rhesus monkey, however, has numerous advantages to the rodent and marmoset that make it a superior and irreplaceable animal model for studying stroke in the brain. In the present study, after mapping the preferred hand representation in two healthy male monkeys with intracortical micro-stimulation, ET-1 was microinjected into the contralateral motor cortex (M1) to its preferred hand.

[Impact of particle size and morphology on zinc cation adsorption by hydroxyapatite and dentifrice containing hydroxyapatite].

Objective: To study the influence of particle size and morphology on zinc cation adsorption by hydroxyapatite (HA) and dentifrice containing HA.

Methods: Four HAs with different particle sizes and morphologies, HA-containing dentifrice and blank dentifrice were prepared into suspensions of serial concentrations. Zinc ion solutions with an initial concentration of 10 mg/L was mixed with the suspensions and kept for 24 h for adsorption reaction.

[Establishment of tree shrew chronic morphine dependent model].

The clinical use of morphine to reduce pain is limited because of its drug tolerance, dependence and addiction. In the present study, the tree shrews (Tupaia belangeri chinensis) developed morphine tolerance and chronic morphine dependence by morphine injections with increasing doses (5, 10, 15, 20 mg/kg body weight for 7 days). Meanwhile, the naloxone (1.

[Nanoleakage at the resin-dental interface of four self-etching adhesives].

Objective: To evaluate the nanoleakage and ultramorphology of four self-etching adhesives.

Methods: Sixteen freshly extracted, caries-free human third molars were selected. A flat dentin surface was exposed by removing occlusal enamel.

[Experimental study on pulp revitalization of Beagle dog's immature permanent teeth after pulpectomy].

Objective: To observe the process of pulp revitalization of immature permanent teeth after pulpectomy.

Methods: Thirty-two single-rooted teeth with open apices from 4 Beagle dogs aged 4 months were included in the study. The pulpal tissues of 8 front teeth with single root of each dog were removed, and a blood clot was produced to the level of the cementoenamel junction followed by a double seal of mineral trioxide aggregate and composite resin.

Differently lasting effects of prenatal and postnatal chronic clozapine/haloperidol on activity and memory in mouse offspring.

Unlabelled: We evaluated the behavioral effects of chronic haloperidol (HAL) and clozapine (CLO) during gestation and CNS development, compared with transient treatments that stopped 1-3 weeks before the test.

Results: 1) Chronic HAL (6 mg/l in drinking water) but not HAL-withdrawal caused hypo-activity in open-field test on postnatal days (PNDs) 35, 42 and 56. However, hyper-activity was found in both CLO (90 mg/l) and CLO-withdrawal pups.

[Methods for single unit recording in behavioring morphine craving rat].

In this paper, one method was introduced, which was a combination of the cue-related morphine addiction model and a technique for obtaining chronic extracellular recordings of single unit in freely moving rats. With the combination and improvement of this technique, we have successfully applied this new method to study the neuronal activity of the hippocampus CA1 region in morphine withdrawal rats. In all, we found some more accurate and objective cellular characteristics of hippocampal neurons, and considered these characteristics as one of electrophysiological indexes of morphine addiction rats.