The effect of a lidocaine/prilocaine topical anesthetic on pain and discomfort associated with orthodontic elastomeric separator placement

Systematic review on effects of experimental orthodontic tooth displacement on brain activation assessed by fMRI

BACKGROUND

Orthodontic treatment is often accompanied by discomfort and pain in patients, which are believed to be a result of orthodontic tooth displacement caused by the mechanical forces exerted by the orthodontic appliances on the periodontal tissues. These lead to change blood oxygen level dependent response in related brain regions.

OBJECTIVE

This systematic review aims to assess the impact of experimental orthodontic tooth displacement on alterations in central nervous system activation assessed by tasked based and resting state fMRI.

MATERIALS AND METHODS

A literature search was conducted using online databases, following PRISMA guidelines and the PICO framework. Selected studies utilized magnetic resonance imaging to examine the brain activity changes in healthy participants after the insertion of orthodontic appliances.

RESULTS

The initial database screening resulted in 791 studies. Of these, 234 were duplicates and 547 were deemed irrelevant considering the inclusion and exclusion criteria. Of the ten remaining potential relevant studies, two were excluded during full-text screening. Eight prospective articles were eligible for further analysis. The included studies provided evidence of the intricate interplay between orthodontic treatment, pain perception, and brain function. All of the participants in the included studies employed orthodontic separators in short-term experiments to induce tooth displacement during the early stage of orthodontic treatment. Alterations in brain activation were observed in brain regions, functional connectivity and brain networks, predominantly affecting regions implicated in nociception (thalamus, insula), emotion (insula, frontal areas), and cognition (frontal areas, cerebellum, default mode network).

CONCLUSIONS

The results suggest that orthodontic treatment influences beyond the pain matrix and affects other brain regions including the limbic system. Furthermore, understanding the orthodontically induced brain activation can aid in development of targeted pain management strategies that do not adversely affect orthodontic tooth movement. Due to the moderate to serious risk of bias and the heterogeneity among the included studies, further clinical trials on this subject are recommended.

Incisor torque expression characteristics in two passive self-ligating brackets placed at different heights. A finite element investigation

Objective

This study investigated torque expression in maxillary incisors using two passive self-ligating bracket types (Damon Q and Pitts 21) placed at different heights using the Finite element method.

Materials and methods

Two passive self-ligating brackets, Damon Q (Ormco, USA) and Pitts 21 (OC Orthodontics, USA) were 3D modeled using micro-computed tomography. Damon Q (0.022ˮ x 0.028″ slot size) and Pitts 21 (0.021ˮ x 0.021″ slot size) brackets were placed on a maxillary central incisor at predetermined vertical heights. Arch wires of size 0.019ˮ x 0.025″ stainless steel (Damon Q) and 0.020ˮ x 0.020" Titanium Molybdenum (Pitts 21) were placed in the bracket slots.

Results

Pitts 21 brackets showed higher torquing moments at all bonding heights as compared to Damon Q brackets. The minimum torquing moment was 9.03Nmm at 5 mm for Damon Q and the maximum torquing moment was 14.92Nmm for Pitts 21 at a bracket bonding height of 8 mm. Total deformation for Pitts 21 at a height of 5 mm from the incisal edge was 0.61 × 10-6mm as compared to that of Damon Q which was 0.41 × 10-6mm. Lowest Von Mises stress values were at 27.07 MPa in Damon Q brackets at a bracket height of 5 mm from the incisal edge. Highest Von Mises stress values were 36.80 MPa for Pitts 21 brackets at a bracket height of 8 mm from the incisal edge.

Conclusion

Pitts 21 brackets exhibited superior torquing characteristics compared to Damon Q. Total deformation in Pitts 21 was higher than Damon Q at all tested bracket bonding heights.

An in vitro evaluation of aligner force decay in artificial saliva

Background/purpose

The present study aimed to compare the force decay of invisible aligners for maxillary anterior teeth with 0.1 mm (D₁), 0.2 mm (D₂), and 0.3 mm (D₃) labial movement within a simulated oral environment over 7 days.

Materials and methods

The prepared invisible aligners were immersed in saliva (S) and subjected to applied force (F) for 7 days. The aligners were set and placed on the maxillary right central incisor with 0.1 mm (D₁), 0.2 mm (D₂), and 0.3 mm (D₃) labial movement. Thin-film pressure sensors were used to measure the aligner force changes. The data were collected and analyzed by statistical methods.

Results

Significant differences were observed in the initial and first-day force between the D₂ and D₃ groups under simulated oral environment force (SF) (P < 0.05). There was a significant difference in force decay between Day 1 and Day 7 for all groups (P < 0.05). The SFD₁ group showed a significant decrease in force on Day 5 (P < 0.05), while the SFD₂ and SFD₃ groups showed significant force decay on Day 4 (P < 0.05). The force decay ratio on Day 7 was higher in the SFD₃ group than in the SFD₁ and SFD₂ groups, but no significant difference was observed.

Conclusion

Larger labial movement of the aligners resulted in higher force decay under artificial saliva environments, and the force decay of invisible aligners was increased by immersion time in artificial saliva.

Effect of Injectable platelet-rich fibrin (i-PRF) on new bone formation in surgical expansion with mini-screw assisted rapid palatal expander: A dog model study

OBJECTIVES

The objective of the study is to test whether the local injection of i-PRF may affect osteoblast, blood vessels and new bone formation in surgically expanded mid palatal suture using maxillary skeletal expander.

MATERIALS AND METHODS

Eighteen adult male local breed dogs were divided randomly into three groups: group I (control), includes the expansion with maxillary skeletal expander that was done without corticotomy and i-PRF. Group II, involves the expansion that was done with mid palatal corticotomy but without i-PRF injection. Group III, has the expansion that was done with mid palatal corticotomy and has injection with 2 ml of i-PRF. Each group consisted of 6 dogs which were subdivided into 3 dogs. Three dogs were sacrificed after 15 days and the other 3 dogs were sacrificed after 45 days. The number of osteoblast, blood vessels and new bone formation percentage were statistically analyzed using Sigma plot platform. Mean and standard error, ANOVA and Duncan were performed among the different groups. Values of P ≤ 0.05 were considered significant.

RESULTS

After expansion, the i-PRF group demonstrated a considerable increase in the amount of new bone in the mid-palatal suture at 15 and 45 days compared with other 2 groups which were indicated by highest percentages of new bone formation (29.30% of 15 days and 76.55% at 45 days) if compared to control group which were (7.72% at 15 days and 22.30% at 45 days). The corticotomy groups were in between, 15.33% and 46.84% respectively. Moreover the number of osteoblasts was higher in corticotomy with i-PRF group on 15 days and decreased on 45 days than the other two groups, while the blood vessels were highest in this group than the other two groups both on 15 and 45 days.

CONCLUSION

I-PRF enhanced the production of osteoblast, blood vessels, and new bone in the surgically expanded mid palatal suture.

Altered spontaneous neural activity in experimental odontogenic pain: a resting-state functional MRI study

OBJECTIVE

This study aimed to evaluate the intrinsic cerebral activity alternations in experimental odontogenic pain with resting-state functional magnetic resonance imaging (fMRI).

MATERIALS AND METHODS

Forty-nine participants in an odontogenic pain group and 49 participants in control group underwent imaging using fMRI in this prospective study. Odontogenic pain was induced by experimental tooth movement. We calculated the fractional amplitude of low-frequency fluctuation (fALFF) value to evaluate regional cerebral function and compared it between the two groups utilizing a voxel-based two-sample t-test.

RESULTS

In comparison with the healthy controls, the participants in odontogenic pain group showed increased fALFF value in the left cerebellum, right posterior cingulate gyrus, and bilateral inferior temporal gyrus, as well as decreased fALFF in the medial prefrontal cortex, the left anterior cingulate cortex, bilateral angular gyrus, left inferior parietal cortex, middle temporal gyrus, and miscellaneous cerebral regions (P < 0.001 familywise error-corrected VOXEL > 100).

CONCLUSION

The present study showed abnormal cerebral activity in odontogenic pain, and reveled that the aberrant regional functional activities were mainly located within the default mode network. The finding could provide insight into the underlying neural mechanism of odontogenic pain. Registry of clinical trials (Trial number ChiCTR1800018589) - http://www.chictr.org.cn/showproj.aspx?proj=31424.

Qualitative and quantitative three-dimensional evaluation of maxillary basal and dentoalveolar dimensions in patients with and without maxillary impacted canines

Background

This study aimed to three-dimensionally evaluate the qualitative and quantitative maxillary basal, dentoalveolar, and dental dimensions in patients with unilateral or bilateral maxillary impacted canines relative to their normal peers.

Materials and methods

This is a retrospective comparative study. Cone-beam computed tomography images of one hundred and fifty adult patients were divided into three equal groups: unilateral, bilateral, and control groups. Each had 50 patients that were three-dimensionally analysed. The quantitative measurements involved three basal (molar basal width, premolar basal width, and arch depth), seven dentoalveolar (molar alveolar width, premolar alveolar width, inter-molar width, inter-premolar width, inter-canine width, arch length, and arch perimeter), and two dental (canine length and width) measurements. The qualitative measurements included four bone density areas (buccal, lingual, mesial, and distal) around the maxillary impacted canines.

Result

Differences between the three groups were statistically different for the quantitative measurements involving the two basal variables (molar basal width and premolar basal width) and all measured dentoalveolar variables; these were smaller in the unilateral and bilateral groups compared with the control group (p < 0.001). Unilateral and bilateral impacted canine groups showed significantly wider and shorter canines than the control group (p < 0.001). The qualitative measurements (the four bone density areas) around unilateral and bilateral impacted canine groups showed significantly greater density than the control group (p < 0.001). There was no significant qualitative or quantitative difference between the unilateral and bilateral impacted canines. The three groups had no significant variations in terms of arch depth.

Conclusion

Maxillary unilateral and bilateral canine impactions are associated with reduced basal and dentoalveolar dimensions as well as wider and shorter maxillary canines compared to normal peers. The quality of bone around unilateral and bilateral impacted maxillary canines is higher than in non-impacted cases. Unilateral and bilateral canine impactions have quite similar qualitative and quantitative parameters.

Evaluation of maxillary arch width and palatal volume and depth in patients with maxillary impacted canine by CBCT

Introduction

Canines are the second most common tooth in terms of impaction. Impacted teeth can be associated with some different indices of dental arch and dentoalveolar structures. The aim of this study was to evaluate maxillary arch width as well as volume and depth of palate in patients with maxillary impacted canine by cone beam computed tomography (CBCT).

Methods

In this cross-sectional study, 45 CBCT images of patients with unilateral maxillary impacted canines were examined. All patients had palatally impacted canines. Three parameters of maxillary arch width, palatal volume and palatal depth were assessed using axial and sagittal incisions on the CBCT images. Then all the measurements on the impacted side were compared with the non-impacted side. Data were entered into SPSS software and paired sample t-test and Student's t-test were used to comparison. The significance level of 0.05 was considered.

Results

The maxillary arch width on the impacted side was significantly less than the normal side (P < 0.001). The mean depth of the palate was 14.86 ± 3.53 mm. There was a significant correlation between canine impaction and Palatal volume (R = 0.728 and P-value< 0.001), but no significant correlation between canine impaction and Maxillary arch width was shown (R = 0.15 and p-value = 0.326).

Conclusion

The impacted canine was significantly associated with a reduction in the width of the maxillary arch on the affected side, and it made no difference if the impacted side was left or right. Also, impacted canine teeth were significantly associated with volume reduction on the affected side.

Molecular mechanism in trigeminal nerve and treatment methods related to orthodontic pain

BACKGROUND

Orthodontic treatment is the main treatment approach for malocclusion. Orthodontic pain is an inevitable undesirable adverse reaction during orthodontic treatment. It is reported orthodontic pain has become one of the most common reason that patients withdraw from orthodontic treatment. Therefore, understanding the underlying mechanism and finding treatment of orthodontic pain are in urgent need.

AIMS

This article aims to sort out the mechanisms and treatments of orthodontic pain, hoping to provide some ideas for future orthodontic pain relief.

MATERIALS

Tooth movement will cause local inflammation. Certain inflammatory factors and cytokines stimulating the trigeminal nerve and further generating pain perception, as well as drugs and molecular targeted therapy blocking nerve conduction pathways, will be reviewed in this article.

METHOD

We review and summaries current studies related to molecular mechanisms and treatment approaches in orthodontic pain control.

RESULTS

Orthodontics pain related influencing factors and molecular mechanisms has been introduced. Commonly used clinical methods in orthodontic pain control has been evaluated.

DISCUSSION

With the clarification of more molecular mechanisms, the direction of orthodontic pain treatment will shift to targeted drugs.

The Medial Thalamus Plays an Important Role in the Cognitive and Emotional Modulation of Orofacial Pain: A Functional Magnetic Resonance Imaging-Based Study

The thalamus plays a critical role in the perception of orofacial pain. We investigated the neural mechanisms of orofacial pain by exploring the intrinsic functional alterations of the thalamus and assessing the changes in functional connectivity (FC) between the thalamic subregions with significant functional alterations and other brain regions in orofacial pain using the seed-based FC approach. There were 49 participants in the orofacial pain group and 49 controls. Orofacial pain was caused by orthodontic separators. The resting-state functional magnetic resonance imaging data of the two groups were analyzed to obtain the fractional amplitude of low-frequency fluctuations (fALFF) of the thalamus; the thalamic subregions with significant fALFF abnormalities were used as seeds for FC analysis. Student's t-tests were used for comparisons. Pearson's correlation analysis was performed using SPM software. Forty-four participants with orofacial pain (mean age, 21.0 ± 0.9 years; 24 women) and 49 age- and sex-matched controls (mean age, 21.0 ± 2.6 years; 27 women) were finally included. Compared with the control group, the orofacial pain group demonstrated the following: (1) increased function in the dorsal area of the thalamus and decreased function in the medial thalamus; (2) decreased FC between the medial thalamus and 12 brain regions (p < 0.05, family-wise error corrected, voxel > 100); and (3) potential positive and negative correlations between the medial thalamus-seeded FC and visual analog scale score changes (p < 0.05, AlphaSim corrected). The findings show that the medial and dorsal thalami play important roles in orofacial pain perception, and that the medial thalamus likely plays an important role in the cognitive and emotional modulation of orofacial pain.

Effects of ibuprofen and low-level laser therapy on orthodontic pain by means of the analysis of interleukin 1-beta and substance P levels in the gingival crevicular fluid

OBJECTIVE

The goal of this study was to compare the effects of ibuprofen and low-level laser therapy in alleviating orthodontic pain observed after elastomeric separator placement (ESP) by means of the analysis of interleukin 1‑beta (IL-1β) and substance P (SP) levels in gingival crevicular fluid (GCF) and visual analog scale (VAS).

MATERIALS AND METHODS

A total of 60 subjects requiring ESP for the banding of maxillary first molars were randomly assigned to the ibuprofen, laser, and control groups. The ibuprofen and control groups received, respectively, 400 mg ibuprofen and placebo lactose tablets orally 1 h before ESP; the laser group received a single low-level laser irradiation session immediately after ESP. GCF samples were collected immediately after ESP (day 0) and on days 1, 3, and 7. Pain intensity was evaluated using the VAS immediately after ESP (baseline) and at hours 2 and 6, as well as on days 1, 3, and 7.

RESULTS

Although IL-1β levels increased significantly on days 1, 3, and 7 compared to day 0, intergroup comparison results revealed insignificant differences. SP levels indicated insignificant within-group differences. Only the SP levels of the ibuprofen group showed a significant decrease on days 0 and 1 compared to the laser and control groups. In all groups, VAS scores increased from baseline to a peak level on day 1, followed by a significant decrease on days 3 and 7. Intergroup comparison results of VAS scores indicated less pain intensity in the ibuprofen group compared to the control group at baseline.

CONCLUSIONS

Only the ibuprofen group exhibited significant decreases in SP levels on days 0 and 1, as well as in VAS scores at baseline.

Topical anesthesia for stainless steel crown tooth preparation in primary molars: a pilot study

Background

Placement of full-coverage restorations such as stainless steel crowns (SSCs) for pulpectomy treated primary molars is essential for successful outcomes. The tooth preparation process for SSCs can cause discomfort to gingival tissues since the crown should be seated 1 mm subgingivally. The purpose of this prospective trial was to compare the effectiveness of subgingival and transmucosal application of topical anesthetics on dental pain during SSC tooth preparation among 6- to 8-year-old children.

Methods

A consecutive sample of 27 children, aged 6-8 years, who required an SSC after pulp therapy in primary molars were randomly divided into three groups. Group A received infiltration anesthesia before tooth preparation for SSC placement, whereas in Group B and C, only topical anesthesia was applied subgingivally and transmucosally. Wong-Bakers Faces pain rating scale (WBFPS) scores were recorded after tooth preparation. Faces, Legs, Activity, Cry and Consolability (FLACC) scores were evaluated by two blinded and calibrated investigators through video recordings of the patient during tooth preparation. Data were tabulated, and inter-group comparisons were performed using the Kruskal-Wallis and analysis of variance tests.

Results

Out of the 27 participants, 48% were boys and 52% were girls, with an overall mean age of 6.83 years. Group A showed the least pain scores according to both the scales, followed by Group B and Group C. The pain intensity was statistically significant on both the pain scales with P = 0.003 for FLACC and P < 0.001 for WBFPS.

Conclusion

Subgingival application of topical anesthesia reduced pain to a certain extent but not as effectively as infiltration anesthesia during SSC tooth preparation in primary molars. Transmucosal application of topical anesthesia did not reduce discomfort when compared to the other two interventions.

Pharmacological interventions for pain relief during orthodontic treatment

BACKGROUND

Pain is a common side effect of orthodontic treatment. It increases in proportion to the amount of force applied to the teeth, and the type of orthodontic appliance used can affect the intensity of the pain. Pain during orthodontic treatment has been shown to be the most common reason for people wanting to discontinue treatment, and has been ranked as the worst aspect of treatment. Although pharmacological methods of pain relief have been investigated, there remains some uncertainty among orthodontists about which painkillers are most suitable and whether pre-emptive analgesia is beneficial. We conducted this Cochrane Review to assess and summarize the international evidence relating to the effectiveness of analgesics for preventing this unwanted side effect associated with orthodontic treatment.

OBJECTIVES

The objectives of this review are to determine:- the effectiveness of drug interventions for pain relief during orthodontic treatment; and- whether there is a difference in the analgesic effect provided by different types, forms and doses of analgesia taken during orthodontic treatment.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: the Cochrane Oral Health Trials Register (to 19 June 2017), the Cochrane Central Register of Controlled Trials (CENTRAL;the Cochrane Library 2016, Issue 7), MEDLINE Ovid (1946 to 19 June 2017), Embase Ovid (1980 to 19 June 2017) and CINAHL EBSCO (Cumulative Index to Nursing and Allied Health Literature; 1937 to 19 June 2017). The US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched on the 19 June 2017 for ongoing studies. We placed no restrictions on language or date of publication when searching the electronic databases.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) relating to pain control during orthodontic treatment. Pain could be measured on a visual analogue scale (VAS), numerical rating scale (NRS) or categorical scale.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the search results, agreed the studies to be included and extracted information from the included studies regarding methods, participants, interventions, outcomes, harms and results. We planned to resolve any discrepancies or disagreements through discussion. We used the Cochrane 'Risk of bias' tool to assess the risk of bias in the studies.

MAIN RESULTS

We identified 32 relevant RCTs, which included 3110 participants aged 9 to 34 years, 2348 of whom we were able to include in our analyses. Seventeen of the studies had more than two arms. We were able to use data from 12 trials in meta-analyses that compared analgesics versus control (no treatment or a placebo); nine that compared non-steroidal anti-inflammatories (NSAIDs) versus paracetamol; and two that compared pre-emptive versus post-treatment ibuprofen for pain control following orthodontic treatment. One study provided data for the comparison of NSAIDs versus local anaesthetic.We found moderate-quality evidence that analgesics effectively reduced pain following orthodontic treatment when compared to no treatment or a placebo at 2 hours (mean difference (MD) -11.66 mm on a 0 to 100 mm VAS, 95% confidence interval (CI) -16.15 to -7.17; 10 studies, 685 participants), 6 hours (MD -24.27 mm on a VAS, 95% CI -31.44 to -17.11; 9 studies, 535 participants) and 24 hours (MD -21.19 mm on a VAS, 95% CI -28.31 to -14.06; 12 studies, 1012 participants).We did not find any evidence of a difference in efficacy between NSAID and paracetamol at 2, 6 or 24 hours (at 24 hours: MD -0.51, 95% CI -8.93 to 7.92; 9 studies, 734 participants; low-quality evidence).Very low-quality evidence suggested pre-emptive ibuprofen gave better pain relief at 2 hours than ibuprofen taken post treatment (MD -11.30, 95% CI -16.27 to -6.33; one study, 41 participants), however, the difference was no longer significant at 6 or 24 hours.A single study of 48 participants compared topical NSAIDs versus local anaesthetic and showed no evidence of a difference in the effectiveness of the interventions (very low-quality evidence).Use of rescue analgesia was poorly reported. The very low-quality evidence did not show evidence of a difference between participants taking ibuprofen and participants taking paracetamol (relative risk (RR) 1.5, 95% CI 0.6 to 3.6). Nor did we find evidence of a difference between groups in likelihood of requiring rescue analgesia when ibuprofen was taken pre-emptively compared to after treatment (RR 0.8, 95% CI 0.3 to 1.9).Adverse effects were identified in one study, with one participant developing a rash that required treatment with antihistamines. This was provisionally diagnosed as a hypersensitivity to paracetamol.

AUTHORS' CONCLUSIONS

Analgesics are more effective at reducing pain following orthodontic treatment than placebo or no treatment. Low-quality evidence did not show a difference in effectiveness between systemic NSAIDs compared with paracetamol, or topical NSAIDs compared with local anaesthetic. More high-quality research is needed to investigate these comparisons, and to evaluate pre-emptive versus post-treatment administration of analgesics.

Methodologies in Orthodontic Pain Management: A Review

Introduction:

Patients experience pain and discomfort during active orthodontic treatment with fixed appliances. Pain is considered a subjective response to noxious stimuli. It can vary from person to person and is influenced by certain factors such as age, gender, previous pain experiences, stress or anxiety, and type of appliance.

Objective:

The objective of this literature review was to discuss conventional versus recently introduced treatment modalities used in pain management for orthodontic patients.

Discussion:

According to the reviewed articles, both pharmacological and non-pharmacological methods were introduced in orthodontic pain management. However, orthodontists must use their best professional judgment to assess each case individually and select an appropriate treatment modality based on pain threshold level of an individual.

Conclusion:

Nevertheless, further investigations are required in this field.