INTRODUCTION: Dental pulp stem cells (DPSCs) have received much attention as a promising population of stem cells in regenerative endodontics. Securing a good blood supply during regeneration is a challenging task because of the constricted apical canal opening, which allows only a limited blood supply. The aim of this study was to investigate any potential synergistic effects of dental pulp stem cells and endothelial cells (ECs) on osteo-/odontogenic and angiogenic differentiation in vitro.
Discoveries of immunomodulatory functions in mesenchymal stem cells (MSCs) have suggested that they might have therapeutic utility in treating immune diseases. Recently, a novel MSC population was identified from dental pulp of human supernumerary teeth, and its multipotency characterized. Herein, we first examined the in vitro and in vivo immunomodulatory functions of human supernumerary tooth-derived stem cells (SNTSCs).
Odontoblasts are dentin-secreting cells that survive for the whole life of a healthy tooth. Once teeth are completely erupted, odontoblasts transform into a mature stage that allows for their functional conservation for decades, while maintaining the capacity for secondary and reactionary dentin secretion. Odontoblasts are also critically involved in the transmission of sensory stimuli from the dentin-pulp complex and in the cellular defense against pathogens. Their longevity is sustained by an elaborate autophagic-lysosomal system that ensures organelle and protein renewal.
Recent pain research advances show promise in their application to the relief of acute and chronic clinical dental pain. Regional electroanalgesia, or transcutaneous electrical stimulation, has been used successfully in the treatment of pain associated with peripheral nerve injuries. Electrical stimulation of teeth also may prove useful as a pain control technique during operative dentistry procedures. Another exciting research finding is the discovery of endogenous or natural pain-suppressing pathways in the brain.
This study evaluated the efficacy of hypnosis- and relaxation-induced suggestions for analgesia for reducing the strength and unpleasantness dimensions of pain evoked by noxious tooth pulp stimulation and by cold pressor stimulation. The Tellegen Absorption Questionnaire was used to assess hypnotic susceptibility for 28 subjects in order to match treatment groups according to sex and susceptibility scores. Tooth pulp stimulation consisted of a 1 sec train of 1 msec pulses at a frequency of 100 Hz, applied at 20 sec intervals to the central incisor.
Effects of electroacupuncture on the jaw opening reflex after tooth pulp stimulation were investigated in lightly anesthetized rats. Electroacupuncture stimulation (45 Hz, 5 msec) was delivered to 8 meridian points and 6 nonmeridian ones for 15 min so as to compare the degree of suppression elicited from each point. Significant suppressive effects on the reflex were observed in the cases of Yin-Hsiang, Ho-Ku and Shou-Sanli stimulation and these effects were antagonized by naloxone.
The analgesic effect of "external Qi" emitted from the Qigong practitioner was investigated in rats. In behavioral experiments, the rat's tail-flick and head-movement threshold measurements were used to determine if the "external Qi" had analgesic effect. The results were negative. In electrophysiological study, the "external Qi" shows no significant changes in the pain-related evoked cortical potentials to tooth-pulp stimulation. Thus the results of this study are different from those reported by other investigators.
Responses to electrical stimulation of the tooth pulp were obtained in both baseline and test sessions for subjects receiving acupuncture, 33 per cent nitrous oxide, or control conditions. A signal-detection analysis across sessions showed that both treatment groups demonstrated reduced sensitivity to stimulation, and increases in bias against reporting strong stimuli as painful. (Key words: Acupuncture; Anesthetics, gases, nitrous oxide; Measurement techniques, sensory decision theory; Pain, sensory decision theory).
To elucidate mechanisms involved in analgesia induced by effects of electro-acupuncture (EAP), effects of EAP on evoked potentials and release of substance P (SP) following tooth pulp stimulation (ST) in the superficial layers of the trigeminal nucleus caudalis (Vc-I-II) were studied in the rabbit. The potentials evoked by ST were composed of two main components with conduction velocity of ca. 30 m/sec (fast component) and ca. 12 m/sec (late component). The late component was significantly inhibited by morphine (10 mg/kg, i.v.) or CP-96,345 (5 mg/kg, i.v.), an SP antagonist.
We examined the effects of intravenous injection of several serotonin (5-HT) antagonists on the inhibitory action of electro-acupuncture (EAP) against the nociceptive responses in the trigeminal nucleus caudalis in rabbits. The inhibitory effect of EAP was suppressed by pindolol, methysergide and ICS 205-930, whereas NAN-190 and ketanserin amplified the EAP effect.