Lina Liao

Interventions for accelerating orthodontic tooth movement A systematic review

OBJECTIVE To evaluate the effectiveness of interventions on accelerating orthodontic tooth movement. MATERIALS AND METHODS We searched the databases of PubMed, Embase, Science Citation Index, CENTRAL, and SIGLE from January 1990 to August 2011 for randomized or quasi-randomized controlled trials that assessed the effectiveness of interventions on accelerating orthodontic tooth movement. The processes of study search, selection, and quality assessment were conducted independently in duplicate by two review authors. Original outcome data, if possible, underwent statistical pooling by using Review Manager 5. RESULTS Through a predefined search strategy, we finally included nine eligible studies. Among them, five interventions were studied (ie, low-level laser therapy, corticotomy, electrical current, pulsed electromagnetic fields, and dentoalveolar or periodontal distraction). Six outcomes were evaluated in these studies (ie, accumulative moved distance or movement rate, time required to move tooth to its destination, anchorage loss, periodontal health, pulp vitality, and root resorption). CONCLUSION Among the five interventions, corticotomy is effective and safe to accelerate orthodontic tooth movement, low-level laser therapy was unable to accelerate orthodontic tooth movement, current evidence does not reveal whether electrical current and pulsed electromagnetic fields are effective in accelerating orthodontic tooth movement, and dentoalveolar or periodontal distraction is promising in accelerating orthodontic tooth movement but lacks convincing evidence.

Coronectomy vs. Total Removal for Third Molar Extraction A Systematic Review

The objective of this systematic review was to compare the outcomes between coronectomy and total removal for third molar extractions with high risk of nerve injury and to help practitioners make prudent decisions on whether and how third molars should be removed. PubMed, Embase, Web of Science, CENTRAL, and SIGLE were searched from January 1990 to October 2011 for randomized or non-randomized controlled trials. Four studies met our inclusion criteria. The pooled risk ratio (coronectomy vs. total removal) was 0.11 (95% CI = 0.03-0.36), 1.03 (95% CI = 0.54-1.98), 0.55 (95% CI = 0.28-1.05), and 1.14 (95% CI = 0.57-2.30) for inferior alveolar nerve injury, post-operative infection, dry socket, and pain at 1 wk after surgery, respectively. A relatively high rate of failed coronectomy in one study (38.3%, compared with 2.3%-9.4% in others) may be attributed to a higher proportion of narrowing roots and vertical impactions. Although root migration rate was high (13.2%-85.29%), the migration distances were short (3.06 ± 1.67 mm), and the directions were away from the nerves. Moreover, the rates of re-operation and root exposure were low. Therefore, coronectomy appears superior to total removal for reducing inferior alveolar nerve damage and could be used in clinical practice for third molar extractions with high risk of nerve injury.

Evaluation of pain in rats through facial expression following experimental tooth movement

This study was carried out to evaluate pain in rats by monitoring their facial expressions following experimental tooth movement. Male Sprague-Dawley rats were divided into the following five groups based on the magnitude of orthodontic force applied and administration of analgesics: control; 20 g; 40 g; 80 g; and morphine + 40 g. Closed-coil springs were used to mimic orthodontic forces. The facial expressions of each rat were videotaped, and the resulting rat grimace scale (RGS) coding was employed for pain quantification. The RGS score increased on day 1 but showed no significant change thereafter in the control and 20-g groups. In the 40- and 80-g groups, the RGS scores increased on day 1, peaked on day 3, and started to decrease on day 5. At 14 d, the RGS scores were similar in control and 20-, 40-, and 80-g groups and did not return to baseline. The RGS scores in the morphine + 40-g group were significantly lower than those in the control group. Our results reveal that coding of facial expression is a valid method for evaluation of pain in rats following experimental tooth movement. Inactivated springs (no force) still cause discomfort and result in an increase in the RGS. The threshold force magnitude required to evoke orthodontic pain in rats is between 20 and 40 g.

Comparison of adverse effects between lingual and labial orthodontic treatment A systematic review

OBJECTIVE To compare adverse effects between labial and lingual orthodontic treatments through a systematic review of the literature. MATERIALS AND METHODS The protocol of this systematic review (CRD42012002455) was registered in the International Prospective Register of Systematic Reviews (PROSPERO). An electronic search was conducted in PubMed, Embase, Web of Science, CENTRAL, SIGLE, ProQuest Dissertations & Theses, and ClinicalTrial.gov for articles published between January 1980 and December 2012. Primary outcomes included pain and caries; secondary outcomes were eating difficulty, speech difficulty, oral hygiene, and treatment duration. Meta-analyses were conducted in Comprehensive Meta-Analysis version 2.2.064. RESULTS Six studies were included, two randomized controlled trials and four clinical controlled trials; of these, four were medium quality and two were low quality in terms of the risk of bias. Five of the six outcomes were evaluated in the included studies, and treatment duration was not; pain, eating difficulty, speech difficulty were statistically pooled. Meta-analysis revealed that the pooled odds ratios were 1.20 (95% confidence interval [CI]  =  0.30-4.87) for overall pain, 32.24 (95% CI  =  14.13-73.55) for pain in tongue, 0.08 (95% CI  =  0.04-0.18) for pain in cheek, 0.11 (95% CI  =  0.03-0.42) for pain in lip, 3.59 (95% CI  =  1.85-6.99) for eating difficulty, and 8.61 (95% CI  =  3.55-20.89) for speech difficulty. Sensitivity analysis showed consistent results except for eating difficulty. No publication bias was detected. CONCLUSIONS The likelihood of overall pain was similar between the two modalities. Patients who underwent lingual orthodontic treatment were more likely to suffer from pain in the tongue and less likely to suffer from pain in the cheek and lip. Lingual orthodontic treatment increased the likelihood of speech difficulty. Eating difficulty, oral hygiene, caries, and treatment duration could not be compared in this systematic review.

Diagnostic accuracy of CBCT for tooth fractures: A meta-analysis

OBJECTIVES The objective of this meta-analysis was to determine the diagnostic accuracy of cone-beam computed tomography (CBCT) for tooth fractures in vivo. METHODS PubMed, Embase, Web of Science, ProQuest Dissertations & Theses, CNKI and SIGLE were searched from January 1990 to April 2013 for eligible studies. Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) was employed to assess the quality of the included studies. Meta-analyses were performed in MetaDisc 1.4, Stata 12.1 and StatsDirect 2.7.9. RESULTS Finally, 12 studies were included in this meta-analysis. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and summary receiver operating characteristic were 0.92 (95% CI=0.89-0.94), 0.85 (95% CI=0.75-0.92), 5.68 (95% CI=3.42-9.45), 0.13 (95% CI=0.09-0.18) and 0.94 (95% CI=0.90-0.98), respectively. The pooled prevalence of tooth fractures in patients with clinically-suspected but periapical-radiography-undetected tooth fractures was 91% (95% CI=83%-97%). Positive and negative predictive values were 0.98 and 0.43 (subgroup analysis: 0.98 and 0.28 for endodontically-treated teeth; 0.99 and 0.77 for non-endodontically-treated teeth). CONCLUSION We suggest that CBCT has a high diagnostic accuracy for tooth fractures and could be used in clinical settings. We can be very confident with positive test results but should be very cautious with negative test results, especially for endodontically treated teeth.

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.

The effectiveness of non-surgical maxillary expansion: a meta-analysis

OBJECTIVE To evaluate and compare the effectiveness of rapid maxillary expansion (RME) and slow maxillary expansion (SME). MATERIALS AND METHODS PubMed, Embase, Web of Science, CENTRAL, ProQuest Dissertations & Theses, ClinicalTrial.gov, and SIGLE were searched from January 1980 to October 2012 for randomized or non-randomized controlled trials. The processes of study search, selection, and quality assessment were conducted independently and in duplicate. Original outcome data underwent statistical pooling through Review Manager 5. RESULTS Fourteen eligible studies were finally included and two interventions (RME and SME) studied. Four outcomes (maxillary intermolar width, maxillary intercanine width, maxillary interpremolar width, and mandibular intermolar width) during three time periods (expansion, retention, and net change) were statistically pooled. The sensitivity analysis revealed that the results from the meta-analysis were generally robust. Eggers test and Beggs test detected no publication bias except for maxillary intercanine width in expansion period for SME versus control. CONCLUSIONS SME is effective in expanding maxillary arch, while we cannot determine its effectiveness in mandibular arch expansion. RME is effective in expanding both maxillary and mandibular arches. Furthermore, SME is superior to RME in expanding molar region of maxillary arch, while similar with RME in mandibular arch expansion. However, we cannot compare their effectiveness in maxillary anterior region.

Periodontal CGRP contributes to orofacial pain following experimental tooth movement in rats

Calcitonin-related gene peptide (CGRP) plays an important role in orofacial inflammatory pain. The aim of this study was to determine whether periodontal CGRP contributes to orofacial pain induced by experimental tooth movement in rats. Male Sprague-Dawley rats were used in this study. Closed coil springs were used to deliver forces. Rats were euthanized on 0d, 1d, 3d, 5d, 7d, and 14d following experimental tooth movement. Then, alveolar bones were obtained for immunostaining of periodontal tissues against CGRP. Two hours prior to euthanasia on each day, orofacial pain levels were assessed through rat grimace scale. CGRP and olcegepant (CGRP receptor antagonist) were injected into periodontal tissues to verify the roles of periodontal CGRP in orofacial pain induced by experimental tooth movement. Periodontal CGRP expression levels and orofacial pain levels were elevated on 1d, 3d, 5d, and 7d following experimental tooth movement. The two indices were significantly correlated with each other and fitted into a dose-response model. Periodontal administration of CGRP could elevate periodontal CGRP expressions and exacerbate orofacial pain. Moreover, olcegepant administration could decrease periodontal CGRP expressions and alleviate orofacial pain. Therefore, periodontal CGRP plays an important role in pain transmission and modulation following experimental tooth movement. We suggest that it may participate in a positive feedback aiming to amplify orofacial pain signals.

Expression patterns of nociceptin in rats following experimental tooth movement

OBJECTIVES To determine the expression levels of nociceptin following experimental tooth movement. MATERIALS AND METHODS A total of 72 male Sprague-Dawley rats were divided into two groups: sham and experimental groups. For the experimental group, closed coil springs were used to mimic orthodontic force (80 g) between upper incisors and first molars, and the rats were killed at 0 hours, 4 hours, 12 hours, 1 day, 2 days, 5 days, 7 days, 10 days, and 14 days. All of these procedures were similar for the sham group, except for that no force was applied. The four rats killed at 0 hours without any intervention were used as the baseline control in each group. Trigeminal nucleus caudalis from both the ipsilateral and contralateral sides of force applications were obtained for immunostaining. RESULTS Nociceptin was expressed in both the ipsilateral and contralateral sides of each group. Its expression levels started to increase on day 2, peaked on day 7, and returned to baseline on day 10 in the experimental group, while expression levels started to decrease on day 1 and returned to baseline on day 10 in the sham group. Moreover, the expression levels were similar between the ipsilateral and contralateral sides in each group. CONCLUSION The expression levels of nociceptin were elevated following experimental tooth movement. The anesthetic agent used in this study (chloral hydrate) may have an antagonism with nociceptin. Due to bilateral innervation of anterior teeth and bilateral projection of nerve fibers, the expression levels of nociceptin were similar between ipsilateral and contralateral sides.

The effect of capsaicin on expression patterns of CGRP in trigeminal ganglion and trigeminal nucleus caudalis following experimental tooth movement in rats

ABSTRACT Objectives The aim of this study was to explore the effect of capsaicin on expression patterns of calcitonin gene-related peptide (CGRP) in the trigeminal ganglion (TG) and trigeminal subnucleus caudalis (Vc) following experimental tooth movement. Material and Methods Male Sprague-Dawley rats were used in this study and divided into small-dose capsaicin+force group, large-dose capsaicin+force group, saline+force group, and no force group. Closed coil springs were used to mimic orthodontic forces in all groups except for the no force group, in which springs were inactivated. Capsaicin and saline were injected into periodontal tissues. Rats were euthanized at 0 h, 12 h, 1 d, 3 d, 5 d, and 7 d following experimental tooth movement. Then, TG and Vc were obtained for immunohistochemical staining and western blotting against CGRP. Results Immunohistochemical results indicated that CGRP positive neurons were located in the TG, and CGRP immunoreactive fibers were distributed in the Vc. Immunohistochemical semiquantitative analysis and western blotting analysis demonstrated that CGRP expression levels both in TG and Vc were elevated at 12 h, 1 d, 3 d, 5 d, and 7 d in the saline + force group. However, both small-dose and large-dose capsaicin could decrease CGRP expression in TG and Vc at 1 d and 3 d following experimental tooth movement, as compared with the saline + force group. Conclusions These results suggest that capsaicin could regulate CGRP expression in TG and Vc following experimental tooth movement in rats.