The effects of menstrual phase on orthodontic pain following initial archwire engagement

Orthodontic pain is related to oral health-related quality of life in orthodontic patients

INTRODUCTION

Orthodontic pain (OP) is a subjective experience induced by prolonged force on the teeth in fixed orthodontic treatment. OP acts as a predictor of aspects related to oral health-related quality of life (OHRQOL). It is important to understand the extent of the impact of OP on a patient's daily life, especially on stomatognathic function and social impact.

OBJECTIVE

To assess the correlation between OP and OHRQOL in fixed orthodontic treatment patients.

MATERIAL AND METHODS

The comparative pain rating scale is used to assess pain intensity, while the oral health impact profile-14 (OHIP-14) assesses the impact of OP severity on OHRQOL of 57 patients undergoing fixed orthodontic treatment in the early stages of treatment (1-3 months of treatment) at the Dental Hospital, Universitas Airlangga. Gender, age, and malocclusion classifications were also analyzed for their influence. The data were analyzed using Spearman correlation and two-way analysis of variance (ANOVA).

RESULTS

In the initial phase of treatment, most of the patients (53%) experienced mild OP and moderate OP (39%), and OP was reduced over a week. The overall OHRQOL score was 17.4 ± 8, which indicates a negative impact on OHRQOL. There were also positive correlation dimensions of OHRQOL, which include the dimensions of physical limitations, psychological discomfort, and psychological limitations (r > 0.50). There was a significant difference between age groups in OP perception and OHRQOL (P < 0.05).

CONCLUSIONS

There was a positive correlation between OP intensity and OHRQOL experienced by fixed orthodontic patients at the Dental Hospital, Universitas Airlangga.

The effects of orthodontic treatment type, depression, and treatment need on perceived pain intensity

Objectives:

The objectives of this study were to evaluate how orthodontic treatment type, treatment need, and depression affect perceived pain intensity (PPI).

Material and Methods:

This prospective study included 172 patients (80 girls and 92 boys, mean age 14.32 ± 1.57 years) treated at the Sivas Cumhuriyet University Faculty of Dentistry, Department of Orthodontics. The patients were divided into three groups: the first group was treated with fixed orthodontic appliances, the second group was treated with twin blocks, and the third group was treated with rapid maxillary expansion and reverse headgear (RME/RH). Data were collected and classified with the Index of Orthodontic Treatment Need-Dental Health Component (DHC), Children’s Depression Scale, and Visual Analog Scale. PPI was recorded in the 1st week (T0), 2nd week (T1), the 1st month (T2), 2nd month (T3), 3rd month (T4), and the 6th month (T5).

Results:

PPI was higher in boys at T1 (P = 0.005) compared with girls. There was a significant difference of PPI between the treatment groups at T2 (P = 0.036), T3 (P = 0.012), T4 (P = 0.000), and T5 (P = 0.006). A statistically significant positive correlation was found between DHC and PPI at T3 (r = 0.182; P = 0.000), T4 (r = 0.161; P = 0.03), and T5 (r = 0.189; P = 0.000) time periods. There was no significant correlation between depression and PPI.

Conclusion:

Girls were more resistant to pain than boys. The type of treatment and the need for treatment both had an effect on PPI. Further studies are needed to investigate the effects of psychological states on PPI during orthodontic treatment.

Comparison of pain perception, anxiety, and impacts on oral health-related quality of life between patients receiving clear aligners and fixed appliances during the initial stage of orthodontic treatment

BACKGROUND AND OBJECTIVES

Clear aligner is an advanced orthodontic method with benefits of comfort, aesthetics, and convenience. This study aimed to compare pain perception, anxiety, and impacts on oral health-related quality of life (OHRQoL) between adult patients receiving clear aligners and fixed appliances during the initial stage of orthodontic treatments.

MATERIAL AND METHODS

The two groups were well matched by ages, gender, and levels of malocclusion severity. Pain perception, anxiety, and OHRQoL were assessed through visual analogue scale, state-trait anxiety inventory, and oral health impact profile-14 (OHIP-14), respectively. And the comparison of above scores was performed by two-way analysis of variance.

RESULTS

A total of 110 patients (55 pairs) were enrolled in this study. Orthodontic pain levels peaked on the first day and decreased gradually afterwards in both groups, which were significantly higher in the fixed group on the first, second, fourth, and fifth days. Likewise, anxiety levels peaked on the first day and decreased thereafter, with significant difference on the 1st, 3d, 5th, 7th, and 14th days. Moreover, the OHIP-14 scores increased and peaked on the first day and then gradually decreased for both groups, which were also significantly higher in the fixed group on the 1st, 7th, and 14th days.

LIMITATIONS

More malocclusion types should be used for group matching. The effect of exclusion of small groups should be taken into consideration in sample size calculation. Income was significantly unbalanced between two groups due to higher cost of clear aligners, and random assignment of treatment modalities was unfeasible.

CONCLUSIONS

Patients treated with clear aligners experienced lower pain levels, less anxiety, and higher OHRQoL as compared to those receiving fixed appliances.

N/OFQ modulates orofacial pain induced by tooth movement through CGRP-dependent pathways

BACKGROUND

Nociceptin/orphanin FQ (N/OFQ) has been revealed to play bidirectional roles in orofacial pain modulation. Calcitonin gene-related peptide (CGRP) is a well-known pro-nociceptive molecule that participates in the modulation of orofacial pain. We aimed to determine the effects of N/OFQ on the modulation of orofacial pain and on the release of CGRP.

METHODS

Orofacial pain model was established by ligating springs between incisors and molars in rats for the simulation of tooth movement. The expression level of N/OFQ was determined and pain level was scored in response to orofacial pain. Both agonist and antagonist of N/OFQ receptor were administered to examine their effects on pain and the expression of CGRP in trigeminal ganglia (TG). Moreover, gene therapy based on the overexpression of N/OFQ was delivered to validate the modulatory role of N/OFQ on pain and CGRP expression.

RESULTS

Tooth movement elicited orofacial pain and an elevation in N/OFQ expression. N/OFQ exacerbated orofacial pain and upregulated CGRP expression in TG, while UFP-101 alleviated pain and downregulated CGRP expression. N/OFQ-based gene therapy was successful in overexpressing N/OFQ in TG, which resulted in pain exacerbation and elevation of CGRP expression in TG.

CONCLUSIONS

N/OFQ exacerbated orofacial pain possibly through upregulating CGRP.

CGRP Modulates Orofacial Pain through Mediating Neuron-Glia Crosstalk

Calcitonin gene-related peptide (CGRP) plays a crucial role in the modulation of orofacial pain, and we hypothesized that CGRP mediated a neuron-glia crosstalk in orofacial pain. The objective of this study was to elucidate the mechanisms whereby CGRP mediated trigeminal neuron-glia crosstalk in modulating orofacial pain. Orofacial pain was elicited by ligating closed-coil springs between incisors and molars. Trigeminal neurons and satellite glial cells (SGCs) were cultured for mechanistic exploration. Gene and protein expression were determined through immunostaining, polymerase chain reaction, and Western blot. Orofacial pain was evaluated through the rat grimace scale. Our results revealed that the expressions of CGRP were elevated in both trigeminal neurons and SGCs following the induction of orofacial pain. Intraganglionic administration of CGRP and olcegepant exacerbated and alleviated orofacial pain, respectively. The knockdown of CGRP through viral vector-mediated RNA interference was able to downregulate CGRP expressions in both neurons and SGCs and to alleviate orofacial pain. CGRP upregulated the expression of inducible nitric oxide synthase through the p38 signaling pathway in cultured SGCs. In turn, L-arginine (nitric oxide donor) was able to enhance orofacial pain by upregulating CGRP expressions in vivo. In cultured trigeminal neurons, L-arginine upregulated the expression of CGRP, and this effect was diminished by cilnidipine (N-type calcium channel blocker) while not by mibefradil (L-type calcium channel blocker). In conclusion, CGRP modulated orofacial pain through upregulating the expression of nitric oxide through the p38 signaling pathway in SGCs, and the resulting nitric oxide in turn stimulated CGRP expression through N-type calcium channel in neurons, building a CGRP-mediated positive-feedback neuron-glia crosstalk.

Thermo-Mechanical Properties of Glass Fiber Reinforced Shape Memory Polyurethane for Orthodontic Application

OBJECTIVES

Glass fiber reinforced shape memory polyurethane (GFRSMPU) has great potential to be an alternative kind of material for orthodontic archwires for overcoming the disadvantages of metal wires in terms of esthetic and allergy and deficiency of pure shape memory polyurethane (SMPU) wires in mechanical properties. The objective of this study was to investigate the thermo-mechanical properties and shape recovery functions of GFRSMPU and evaluate the feasibility of using this composite for orthodontic archwires.

MATERIAL AND METHODS

GFRSMPU were made from short cut glass fibers and SMPU by mixing extrusion. Scanning electron microscope (SEM) and differential scanning calorimetry (DSC) were performed to investigate the distribution of glass fibers in the mixture and glass transition temperature (T_g). Then the thermo-mechanical properties, including tensile modulus, flexural modulus and stress relaxation effects, were measured. Furthermore, shape recovery functions of GFRSMPU characterized by the shape recovery ratio and force were investigated through shape recovery tests, typodont models and finite element analysis (FEA).

RESULTS

SEM images indicated that an excellent dispersity of glass fibers was obtained after double-extrusion. DSC experiments showed T_g was not enormously affected with the existence of glass fibers, but the mechanical properties of GFRSMPU were greatly improved. Shape recovery tests showed reduction of shape recovery ratio of the GFRSMPU material with the addition of glass fibers, but dentition aligning time was reduced by 50% in the simulation performed on identical typodont models with GFRSMPU archwires filled with 30 wt.% glass fibers. The FEA results illustrated that the reacting forces of GFRSMPU archwires with 30 wt.% glass fiber was increased by 96.36% compared with pure SMPU archwires.

CONCLUSIONS

The mechanical properties of GFRSMPU can be considerably improved by adding glass fibers, and the shape memory function would be well preserved too. Enhanced SMPU owns a good application prospect in orthodontics for dentation aligning on the preliminary stage, as well as other medical fields.