Effect of celecoxib on emotional stress and pain-related behaviors evoked by experimental tooth movement in the rat

The efficacy of analgesics in controlling orthodontic pain: a systematic review and meta-analysis

Background

Patients who had gone through orthodontic treatment experienced pain and discomfort which could be the highest-ranking reason for treatment disturbance or early termination. Thus, this review aimed to assess the efficacy of analgesics on the relief of pain in orthodontic treatment.

Methods

A computerized literature search was conducted in the databases of EMBASE (via OVID, 1974 to 2019 Week 50), MEDLINE (via OVID, 1946 to Dec 2019), the Cochrane Central Register of Controlled Trials (CENTRAL) (December 2019). The Cochrane Collaboration’s Review Manager 5.3 software was applied in the present study. And methodological quality was evaluated by the Cochrane Risk of Bias Tool.

Results

We identified twelve publications including 587 patients in 19 randomized controlled trials. The results showed that the mean difference of naproxen in visual analogue scale (VAS) were − 1.45 (95% CI -2.72, − 0.19; P = .02), − 2.11 (95% CI -3.96, − 0.26; P = .03) and − 1.90 (95% CI -3.33, − 0.47; P = .009) in 2 h, 6 h and 24 h respectively. As for ibuprofen, the standard mean differences were − 1.10 (95% CI -1.49, − 0.71), − 1.63(95% CI -2.32, − 0.95) and − 1.34 (95% CI -2.12, − 0.55) at 2 h, 6 h, and 24 h, with the overall P values all < 0.001. The mean difference of acetaminophen is − 0.68, − 1.34, − 1.91 at three time points and the overall P values all < 0.01.

Conclusions

This meta-analysis suggests that the use of analgesics is effective for patients in controlling orthodontic pain. Ibuprofen and naproxen are both of stable analgesic effects which could peak at 6 h, while the analgesic effect of acetaminophen increases steadily from 2 h through 24 h. Compared with ibuprofen and acetaminophen, naproxen shows a stronger analgesic effect either at 2 h or 6 h, and its effect lasts to 24 h.

Different Therapeutic Effects of CO2 and Diode Laser Irradiation on Tooth Movement-Related Pain

Although orthodontic treatment is common, orthodontic force often induced pain. Low-level laser therapy (LLLT) has been investigated to improve therapeutic comfort. In dentistry, LLLT is mainly applied using two types of lasers, CO₂ and diode lasers, whose biological actions are thought to be associated with wavelength (CO₂: 10,600 nm; diode: 808 nm). The analgesic effect of LLLT on orthodontic treatment-related pain is widely reported but inconsistent. This study aimed to (1) determine whether irradiation with a CO₂ or diode laser attenuates orthodontic treatment-related pain using the jaw-opening reflex model, (2) elucidate the optimal irradiation protocol for both lasers to obtain the maximal analgesic effect, (3) evaluate the effects of laser irradiation on other biological features [e.g., tooth movement, glial fibrillary acidic protein (GFAP) expression, and temperature alterations] and (4) investigate the mechanism underlying the analgesic effect of laser irradiation. In this animal model, orthodontic treatment-induced pain manifested as a significantly reduced the threshold for inducing the jaw-opening reflex on the orthodontically treated side compared with the contralateral side. GFAP expression in the bilateral trigeminal ganglia (TGs) was significantly increased by the application of orthodontic force. CO₂ laser irradiation of the orthodontically treated region significantly increased the threshold for inducing the jaw-opening reflex and the peripheral temperature. Similar reductions in jaw-opening reflex excitability were induced by surface anesthesia and thermal stimulation but not, the diode laser. Neither CO₂ nor diode laser irradiation altered GFAP expression in the TGs. Infiltration anesthesia also significantly increased the threshold for inducing the jaw-opening reflex on each anesthetized side. Irradiation (30 s) by either laser immediately after orthodontic force application (preirradiation) significantly decreased jaw-opening reflex excitability and GFAP expression in the bilateral TGs the next day. However, thermal stimulation immediately after orthodontic force application failed to alter jaw-opening reflex excitability the next day. Laser irradiation did not alter tooth movement; however, an optimized irradiation protocol for aiding tooth movement is suggested. In conclusion, both CO₂ and diode lasers are able to prevent orthodontic treatment-related pain. Furthermore, the involvement of temperature alterations and surface anesthesia in the analgesic effect induced by CO₂ laser irradiation is suggested.

TRPV1 and TRPV1-Expressing Nociceptors Mediate Orofacial Pain Behaviors in a Mouse Model of Orthodontic Tooth Movement

Orthodontic force produces mechanical irritation and inflammation in the periodontium, which is inevitably accompanied by pain. Despite its prevalence, treatment of orthodontic pain is ineffective. Elucidating underlying neural mechanisms is critical to improving the management of orthodontic pain. We have assessed the contribution of transient receptor potential vanilloid subtype 1 (TRPV1) and the TRPV1-expressing subset of nociceptive afferents to pain behaviors induced by orthodontic force in mice. Microfocus X-ray computed tomography analysis showed that application of an orthodontic force of 10 g to the maxillary first molar produced reliable tooth movement in mice. Mouse grimace scale (MGS) was evaluated as an indication of non-evoked spontaneous pain and bite force (BF) was measured for assessing bite-evoked nocifensive behaviors. Orthodontic force increased MGS and decreased BF, both of which were interpreted as increased levels of pain. These behaviors peaked at 1d and returned near to the sham level at 7d. Retrograde labeling and immunohistochemical assays showed TRPV1-expressing peptidergic afferents are abundantly projected to the periodontium. Direct injection of resiniferatoxin into trigeminal ganglia (TG) decreased TRPV1-expressing afferents by half in the targeted region of TG. The chemical ablation of TRPV1-expressing afferents significantly attenuated orthodontic pain behaviors assessed by MGS and BF. Consistently, the knockout of TRPV1 also attenuated orthodontic force-induced changes in MGS and BF. These results suggest that TRPV1 and TRPV1-expressing trigeminal nociceptors constitute a primary pathway mediating orthodontic pain behaviors in mice. This model will be useful for mechanistic studies on orthodontic pain aimed at developing novel approaches for painless orthodontics.

Correlation between pain and hyalinization during tooth movement induced by different types of force

OBJECTIVES

To evaluate the correlation between pain and tissue reactions during induced tooth movement (ITM).

MATERIALS AND METHODS

Forty-two male Wistar rats (Rattus norvegicus; ∼90 days of age, 300 g) were used. The animals were divided into seven groups of six rats each: one control group and six experimental groups subjected to ITM by continuous force (CF) or interrupted continuous force (ICF) for 1, 3, and 5 days. Hyalinization of the periodontal ligament (PL) and occurrence of pain were observed. Animal behavior (walking, climbing, immobile posture, resting/sleeping, and directed face grooming) and the presence of chemical mediators associated with nociception, cyclooxygenase-2 (COX-2), and interleukin-1 beta (IL-1β) in the PL were analyzed.

RESULTS

There was a moderate positive correlation between hyalinization and the presence of COX-2 (r_s = 0.404; P < .05) and IL-1β (r_s = 0.429; P < .05). There was a moderate negative correlation between hyalinization and exploratory behaviors (walking, r = -0.586, P < .01; climbing, r = -0.573, P < .01), and a moderate positive correlation between hyalinization and resting/sleeping (r = 0.467; P < .01).

CONCLUSIONS

The results suggest a correlation between pain and undesirable tissue reactions in ITM.

Orthodontic treatment-induced temporal alteration of jaw-opening reflex excitability

The impairment of orofacial motor function during orthodontic treatment needs to be addressed, because most orthodontic patients experience pain and motor excitability would be affected by pain. In the present study, the temporal alteration of the jaw-opening reflex excitability was investigated to determine if orthodontic treatment affects orofacial motor function. The excitability of jaw-opening reflex evoked by electrical stimulation on the gingiva and recorded bilaterally in the anterior digastric muscles was evaluated at 1 (D1), 3 (D3), and 7 days (D7) after orthodontic force application to the teeth of right side; morphological features (e.g., osteoclast genesis and tooth movement) were also evaluated. To clarify the underlying mechanism of orthodontic treatment-induced alteration of orofacial motor excitability, analgesics were administrated for 1 day. At D1 and D3, orthodontic treatment significantly decreased the threshold for inducing the jaw-opening reflex but significantly increased the threshold at D7. Other parameters of the jaw-opening reflex were also evaluated (e.g., latency, duration and area under the curve of anterior digastric muscles activity), and only the latency of the D1 group was significantly different from that of the other groups. Temporal alteration of the jaw-opening reflex excitability was significantly correlated with changes in morphological features. Aspirin (300 mg·kg^-1·day^-1) significantly increased the threshold for inducing the jaw-opening reflex, whereas a lower dose (75-150 mg·kg^-1·day^-1) of aspirin or acetaminophen (300 mg·kg^-1·day^-1) failed to alter the jaw-opening reflex excitability. These results suggest that an increase of the jaw-opening reflex excitability can be induced acutely by orthodontic treatment, possibly through the cyclooxygenase activation.NEW & NOTEWORTHY It is well known that motor function is affected by pain, but the effect of orthodontic treatment-related pain on the trigeminal motor excitability has not been fully understood. We found that, during orthodontic treatment, trigeminal motor excitability is acutely increased and then decreased in a week. Because alteration of trigeminal motor function can be evaluated quantitatively by jaw-opening reflex excitability, the present animal model may be useful to search for alternative approaches to attenuate orthodontic pain.

Current advances in orthodontic pain

Orthodontic pain is an inflammatory pain that is initiated by orthodontic force-induced vascular occlusion followed by a cascade of inflammatory responses, including vascular changes, the recruitment of inflammatory and immune cells, and the release of neurogenic and pro-inflammatory mediators. Ultimately, endogenous analgesic mechanisms check the inflammatory response and the sensation of pain subsides. The orthodontic pain signal, once received by periodontal sensory endings, reaches the sensory cortex for pain perception through three-order neurons: the trigeminal neuron at the trigeminal ganglia, the trigeminal nucleus caudalis at the medulla oblongata and the ventroposterior nucleus at the thalamus. Many brain areas participate in the emotion, cognition and memory of orthodontic pain, including the insular cortex, amygdala, hippocampus, locus coeruleus and hypothalamus. A built-in analgesic neural pathway—periaqueductal grey and dorsal raphe—has an important role in alleviating orthodontic pain. Currently, several treatment modalities have been applied for the relief of orthodontic pain, including pharmacological, mechanical and behavioural approaches and low-level laser therapy. The effectiveness of nonsteroidal anti-inflammatory drugs for pain relief has been validated, but its effects on tooth movement are controversial. However, more studies are needed to verify the effectiveness of other modalities. Furthermore, gene therapy is a novel, viable and promising modality for alleviating orthodontic pain in the future.

Controlling pain during orthodontic fixed appliance therapy with non-steroidal anti-inflammatory drugs (NSAID): a randomized, double-blinded, placebo-controlled study

BACKGROUND

Despite all the technological advances in orthodontics, orthodontic treatment still seems to involve some degree of discomfort and/or pain. Pain control during orthodontic therapy is of great concern to both orthodontists and patients. However, there has been limited research into controlling such pain.

AIMS

The purpose of this work was to assess patient-perceived pain following fixed orthodontic treatment and to evaluate the comparative analgesic efficacy of non-steroidal anti-inflammatory drugs for controlling pain.

METHODS

A total of 45 patients about to undergo fixed appliance orthodontic treatment were enrolled in this double-blind prospective study. Patients were evenly and randomly distributed in a blinded manner to one of three groups as follows: paracetamol/acetaminophen 500 mg thrice daily; placebo in the form of empty capsules; and etoricoxib 60 mg once daily. Drug administration began 1 h before initiating the bonding procedure and archwire placement, and given until the day 3. The pain perceived was recorded by the patients on a linear and graded Visual Analogue Scale at time intervals of 2 h after insertion of the appliance; 6 h thereafter and again at nighttime of the same day of the appointment; 24 h later and on the 2nd day at nighttime; 48 h after the appointment and on day 3 at nighttime.

RESULTS

Our results revealed that moderately intense pain is associated with routine orthodontic treatment, and that the amount of pain individuals perceive varies widely. We observed statistically significant differences in the pain control among the three groups, and that etoricoxib 60 mg proved most efficient.

CONCLUSION

Etoricoxib 60 mg is highly efficacious for controlling pain during fixed orthodontic appliance therapy.

Synergistic analgesia of duloxetine and celecoxib in the mouse formalin test: a combination analysis

Duloxetine, a serotonin and noradrenaline reuptake inhibitor, and celecoxib, a non-steroidal anti-inflammatory drug, are commonly used analgesics for persistent pain, however with moderate gastrointestinal side effects or analgesia tolerance. One promising analgesic strategy is to give a combined prescription, allowing the maximal or equal efficacy with fewer side effects. In the current study, the efficacy and side effects of combined administration of duloxetine and celecoxib were tested in the mouse formalin pain model. The subcutaneous (s.c.) injection of formalin into the left hindpaw induced significant somatic and emotional pain evaluated by the biphasic spontaneous flinching of the injected hindpaw and interphase ultrasonic vocalizations (USVs) during the 1 h after formalin injection, respectively. Pretreatment with intraperitoneal (i.p.) injection of duloxetine or celecoxib at 1 h before formalin injection induced the dose-dependent inhibition on the second but not first phase pain responses. Combined administration of duloxetine and celecoxib showed significant analgesia for the second phase pain responses. Combination analgesia on the first phase was observed only with higher dose combination. A statistical difference between the theoretical and experimental ED₅₀ for the second phase pain responses was observed, which indicated synergistic interaction of the two drugs. Concerning the emotional pain responses revealed with USVs, we assumed that the antinociceptive effects were almost completely derived from duloxetine, since celecoxib was ineffective when administered alone or reduced the dosage of duloxetine when given in combination. Based on the above findings, acute concomitant administration of duloxetine and celecoxib showed synergism on the somatic pain behavior but not emotional pain behaviors.

The use of different analgesics in orthodontic tooth movements

OBJECTIVE

To provide a semi-quantitative assessment of the effect of different analgesics (celecoxib, ketorolac, and paracetamol) on tooth movement and bone resorption using immunohistochemical staining of matrix metalloproteinase-13 (MMP-13).

MATERIALS AND METHODS

Forty white male rats (12-weeks old; body weight: 230-250 g) were divided into four groups (10 rats each) and were given the treatment once a day for 2 consecutive months. Group A (control group) rats were given the reverse osmosis water; group B rats were given 10 mg/kg celecoxib; group C rats were given 3 mg/kg ketorolac; and group D rats were given 150 mg/kg paracetamol. A precalibrated closed Sentalloy coil spring was placed inside each rat mouth to deliver a constant force of 50 cN. The magnitude of tooth movement was measured intraorally. After 2 months, the rats were sacrificed, and the sections were mounted on L-polylysine-coated glass slides. Slides from each specimen were stained with hematoxylin and eosin, and others were stained with MMP-13. Data were analyzed with the one-way analysis of variance (ANOVA).

RESULTS

Celecoxib, ketorolac, and paracetamol groups showed tooth movement of 1.81 ± 0.43 mm, 1.13 ± 0.28 mm, and 1.08 ± 0.27 mm, respectively. The mean number of MMP-13-positive osteoclasts was highest in celecoxib-treated group followed by the control group and was decreased in the ketorolac and paracetamol groups. Comparing all groups to the control revealed significant differences (P < .05).

CONCLUSION

Administration of celecoxib did not reduce bone resorption or interfere with tooth movement in rats compared to other analgesics tested (ketorolac and paracetamol).

Does chlorhexidine in different formulations interfere with the force of orthodontic elastics?

OBJECTIVE

To evaluate the effects of different concentrations of chlorhexidine on the decline in force of orthodontic elastics.

MATERIALS AND METHODS

In a laboratory study, five groups of samples were tested, with one control group represented by distilled water (group 1) and four experimental groups: 0.12% manipulated chlorhexidine (group 2), 0.2% manipulated chlorhexidine (group 3), 0.12% chlorhexidine gluconate-based oral solution (0.12% Periogard; group 4), and 0.2% Cleanform mouthwash (formula and action; group 5). The test groups were submersed in artificial saliva at 37°C. Templates were used and submerged in the chlorhexidine solutions for 30 seconds twice a day. Force was measured with a digital dynamometer at six different time intervals: 0, 1, 7, 14, 21, and 28 days.

RESULTS

No statistical differences were found among the groups in the initial period, at 24 hours, and at 7 days (P > .05). There were statistical differences between groups 2 and 5 at 14 days of the experiment and between group 1 and the others at 28 days. In the initial period, the force was statistically higher than it was at any of the other periods of the experiment (P < .05).

CONCLUSION

In the present study, chlorhexidine showed no significant influence on the force degradation of the chain elastics tested.

Orthodontic tooth movement and root resorption in ovariectomized rats treated by systemic administration of zoledronic acid

INTRODUCTION

The effect of zoledronic acid, a potent and novel bisphosphonate, on tooth movement and orthodontically induced root resorption in osteoporotic animals systemically treated with zoledronic acid as similarly used in postmenopausal patients has not been elucidated. Therefore, this study was undertaken.

METHODS

Fifteen 10-week-old female Wistar rats were divided into 3 groups: ovariectomy, ovariectomy + zoledronic acid, and control. Only the ovariectomy and ovariectomy + zoledronic acid groups underwent ovariectomies. Two weeks after the ovariectomy, zoledronic acid was administered only to the ovariectomy + zoledronic acid group. Four weeks after the ovariectomy, 25-g nickel-titanium closed-coil springs were applied to observe tooth movement and orthodontically induced root resorption.

RESULTS

There were significant differences in the amounts of tooth movement and orthodontically induced root resorption between the ovariectomy and the control groups, and also between the ovariectomy and the ovariectomy + zoledronic acid groups. There was no statistically significant difference in tooth movement and orthodontically induced root resorption between the ovariectomy + zoledronic acid and the control groups. Zoledronic acid inhibited significantly more tooth movement and significantly reduced the severity of orthodontically induced root resorption in the ovariectomized rats. The ovariectomy + zoledronic acid group showed almost the same results as did the control group in both tooth movement and orthodontically induced root resorption.

CONCLUSIONS

Zoledronic acid inhibits excessive orthodontic tooth movement and also reduces the risk of severe orthodontically induced root resorption in ovariectomized rats.

Interventions for pain during fixed orthodontic appliance therapy. A systematic review

OBJECTIVE

To compare the different methods of pain control intervention during fixed orthodontic appliance therapy.

MATERIALS AND METHODS

A computerized literature search was performed in MEDLINE (1966-2009), The Cochrane Library (Issue 4, 2009), EMBASE (1984-2009), and CNKI (1994-2009) to collect randomized controlled trials (RCTs) for pain reduction during orthodontic treatment. Data were independently extracted by two reviewers and a quality assessment was carried out. The Cochrane Collaboration's RevMan5 software was used for data analysis. The Cochrane Oral Health Group's statistical guidelines were followed.

RESULTS

Twenty-six RCTs were identified and six trials including 388 subjects were included. Meta-analysis showed that ibuprofen had a pain control effect at 6 hours and at 24 hours after archwire placement compared with the placebo group. The standard mean difference was -0.47 and -0.48, respectively. There was no difference in pain control between ibuprofen, acetaminophen, and aspirin. Other analgesics such as tenoxicam and valdecoxib had relatively lower visual analog scale (VAS) scores in pain perception. Low-level laser therapy (LLLT) was also an effective approach for pain relief with VAS scores of 3.30 in the LLLT group and 7.25 in the control group.

CONCLUSIONS

Analgesics are still the main treatment modality to reduce orthodontic pain despite their side effects. Some long-acting nonsteroidal anti-inflammatory drugs (NSAIDs) and cyclo-oxygenase enzyme (COX-2) inhibitors are recommended for their comparatively lesser side effects. Their preemptive use is promising. Other approaches such as LLLT have aroused researchers' attention.