Expression of substance P, calcitonin gene-related peptide, ß-endorphin and methionine-enkephalin in human dental pulp tissue after orthodontic intrusion: a pilot study.

OBJECTIVE: To determine the levels of two sensory neuropeptides (substance P [SP] and calcitonin gene-related peptide [CGRP]) and two endogenous opioids (methionine-enkephalin [Met-Enk] and ß-endorphin [ß-End]) in dental pulp tissue samples subjected to controlled orthodontic intrusive forces. MATERIALS AND METHODS: Sixteen healthy premolars were selected from eight patients who were undergoing extraction for orthodontic purposes. Eight were randomly used as controls, and the other eight were assigned to an experimental group (controlled orthodontic intrusive forces applied for 24 hours). After this period, teeth were extracted, and pulp samples were obtained. All samples were processed to quantify the expression levels of SP, CGRP, Met-Enk, and ß-End using commercial radioimmunoassay kits. RESULTS: All samples exhibited basal levels of both neuropeptides and endogenous opioids. After 24 hours of the intrusive stimulus, all patients reported a tolerable discomfort localized at the involved premolar. Only SP was significantly increased (P<.05). For the other molecules, no statistically significant differences were observed (P>.05); however, they expressed important increasing trends. CONCLUSIONS: The expression levels of SP and CGRP in dental pulp samples from the experimental group support the positive correlation between the symptomatic clinical scenario and increased expression levels of neuropeptides, clarifying the role of neurogenic inflammation in early injury response.

Effect of experimentally induced occlusal trauma on substance p expression in human dental pulp and periodontal ligament.

INTRODUCTION: The purpose of this study was to quantify the effect of occlusal trauma experimentally induced with occlusal interferences on substance P (SP) expression in healthy human dental pulp and periodontal ligament. METHODS: Twenty-eight human dental pulp and periodontal ligament samples were obtained from healthy premolars in which extraction was indicated for orthodontic reasons. Before extraction, occlusal trauma was induced with experimental occlusal interferences in half of these premolars by placing a resin block over their occlusal surface and submitting patients to chew gum for 30 minutes. The remaining healthy premolars were extracted without occlusal trauma and served as a control group. All dental pulp and periodontal ligament samples were processed, and SP was measured by radioimmunoassay. RESULTS: There was 45% and 120% greater SP expression in dental pulp and periodontal ligament, respectively, of teeth with experimentally induced occlusal trauma. Paired t test showed statistically significant differences for both human dental pulp and periodontal ligament (P = .02 and P < .001, respectively) of teeth submitted to occlusal trauma when compared with control group values. CONCLUSIONS: SP expression in human dental pulp and periodontal ligament increases when teeth are submitted to occlusal trauma experimentally induced with occlusal interferences.

The effect of three different rotary instrumentation systems on substance P and calcitonin gene-related peptide expression in human periodontal ligament.

INTRODUCTION: The purpose of this study was to quantify the effect of three different rotary root canal preparation systems on substance P and calcitonin gene-related peptide expression in healthy human periodontal ligament. METHODS: Fifty periodontal ligament samples were obtained from healthy premolars in which extraction was indicated for orthodontic reasons. Before extraction, 40 of these premolars were equally divided into four groups, and root canals were prepared using four different systems: the ProTaper Universal rotary system, the RaCe rotary system, the Mtwo rotary system, and the hand instrumentation technique. The remaining 10 healthy premolars that were extracted without treatment served as a negative control group. All periodontal ligament samples were processed, and SP and CGRP were measured by radioimmunoassay. RESULTS: Greater SP and CGRP expression were found in the ProTaper Universal group followed by the hand instrumentation group, the RaCe, and the Mtwo groups. The lower SP and CGRP values were for the negative control group. The Kruskal-Wallis test showed statistically significant differences between groups (p < 0.0001). Post hoc Least Significant Difference (LSD) tests showed statistically significant differences in SP and CGRP expression between the negative control group and all the other groups except the Mtwo group. Hand instrumentation also showed statistically significant differences with all the other groups, except the ProTaper Universal group. Differences between the three rotary systems were also statistically significant. CONCLUSION: SP and CGRP expression in periodontal ligament increases when teeth are prepared with ProTaper Universal and RaCe rotary instrumentation systems as well as with hand instrumentation. Mtwo maintains SP and CGRP levels.

The effect of different vasoconstrictors and local anesthetic solutions on substance P expression in human dental pulp.

The purpose of this study was to quantify the effect of the infiltration injection of different vasoconstrictor and anesthetic solutions on substance P (SP) expression in healthy human dental pulp. Thirty pulp samples were obtained from healthy upper premolars in which extraction was indicated for orthodontic reasons and were randomly assigned into three groups of 10 samples each: 2% lidocaine with 1:80,000 epinephrine (Lido group), 3% Prilocaine with 1:200000 felypressin (Prilo group); and 4% Prilocaine without vasoconstrictor (Prilo-no-VC group). All teeth were extracted 10 minutes after anesthetic application. Pulp samples were processed and SP was measured by radioimmunoassay. SP expression for the Lido, Prilo, and Prilo-no-VC groups were 616.49, 663.76, and 760.79 pmol/mg pulp tissue, respectively. Analysis of variance showed statistically significant differences between groups (p = 0.001). Tukey Honestly Significant Difference (HSD) post hoc tests showed significant statistical differences between the Prilo-no-VC group and the Lido group (p < 0.01) and between the Prilo-no-VC group and the Prilo group (p < 0.05). It can be concluded that infiltration injection of local anesthetics with vasoconstrictor attenuate SP expression in human dental pulp.

Semisynthesis of a homogeneous glycoprotein enzyme: ribonuclease C: part 1.

Seven in one blow: The efficient formation of mixed disulfides on the thiol-rich fusion protein A followed by subsequent intein cleavage gave the fragment B with all seven cysteines protected against oxidation. The native chemical ligation of B with synthetic glycopeptide thioesters provides glycoproteins.

The effect of tooth bleaching on substance P expression in human dental pulp.

The purpose of this study was to quantify the effect of tooth bleaching on substance P (SP) expression in healthy human dental pulp. Forty pulp samples were obtained from healthy premolars in which extraction was indicated for orthodontic reasons. Thirty of these premolars were assigned into three different tooth-bleaching protocols: group 1 (n = 10): Opalescence Xtra Boost (Ultradent Products, South Jordan, UT) (38% H(2)O(2)) for 15 minutes; group 2 (n = 10): Lase Peroxide (DMC, Brazil) (35% H(2)O(2)) activated with infrared laser diode (Biolux; BioArt, Brazil) for 3 minutes, and group 3 (n = 10): Zoom! Whitening System (Discuss Dental, Culver City, CA) (25% H(2)O(2)) light activated for 20 minutes. The remaining 10 healthy premolars serve as a control group. Teeth were anesthetized immediately after bleaching and were extracted 10 minutes later. All pulp samples were processed and SP was measured by radioimmunoassay. Greater SP expression was found in the Zoom! Whitening System, followed by the Lase Peroxide group, Opalescence Xtra Boost, and the lower SP values were for the control group. Analysis of variance showed statistically significant differences between groups (p = 0.0001). Tukey HSD post hoc tests showed significant differences in the light (p < 0.01) and laser (p < 0.05) activated bleaching systems when compared with control values. It can be concluded that light- and laser-activated tooth-bleaching systems increase SP expression in human dental pulp significantly higher than normal values.

Variation in the expression of insulin-like growth factor-1 in human pulp tissue according to the root-development stage.

Insulin-like growth factor-1 (IGF-1) plays an important role in cell proliferation and differentiation. It actively participates during odontogenesis and mineralization of dental hard tissues. The purpose of this study is to use a radioimmunoassay (RIA) to determine whether there are differences in the expression of IGF-1 in human pulp from teeth having incomplete or complete root development. Twenty-six pulp samples were obtained from freshly extracted human third molars, half of them from teeth with incomplete root development. All of the samples were processed and labeled using an IGF-1 RIA kit. Results showed IGF-1 presence in all human pulp samples with a statistically significant higher expression in pulps having complete root development. The present findings are consistent with the hypothesis that IGF-1 contributes toward forming and mineralizing dental tissues in teeth with incomplete root development as well as in pulp-repairing process in teeth with complete root development.

The effect of cavity preparation on substance P expression in human dental pulp.

Substance P (SP) plays an important role during neurogenic inflammation of dental pulp. The purpose of this study was to use a radioimmunoassay for determining the effect of cavity preparation on SP expression in healthy human dental pulp. Ten pulp samples were obtained from healthy premolars where extraction was indicated for orthodontic reasons. Deep cavity preparation (<1 mm remaining dentine thickness) was performed before extraction in five of these bicuspids. All samples were processed and I-SP labeled; SP was quantified by competition assay. The results revealed SP expression in all human pulp samples. Mann-Whitney's U test revealed statistically significant higher expression in pulp from teeth where cavity preparation had been performed compared to control values (p < 0.05). These findings suggest that SP is released during common dental procedures (such as cavity preparation) and its expression may have an important clinical significance in terms of experiencing inflammation and pain.

Expression of insulin-like growth factor-1 receptor in human pulp tissue.

Insulin-like growth factor-1 (IGF-1) plays an important role in cell proliferation and differentiation. The purpose of this study was to use a radioreceptor assay to evaluate whether IGF-1 receptors are present in human pulp and to determine whether differences in its expression are found in the pulp tissue of teeth having incomplete or complete root development. Twenty pulps were obtained from freshly extracted human third molars; they were then processed and labeled with I-IGF-1. The results showed IGF-1 receptor expression in all human pulp samples. t test revealed statistically significant higher expression in the pulps from teeth having incomplete root development (P <0.005). Given the functions of this growth factor system in other tissues, the present findings are consistent with the hypothesis that IGF-1 contributes toward forming and mineralizing dental tissues as well as in pulp-repairing processes.