Pain and removal force associated with bracket debonding: a clinical study

Assessment of biofilm formation on ceramic, metal, and plastic brackets in orthodontic materials by new method using renG-expressing Streptococcus mutans

OBJECTIVE

Oral biofilm has a high acid-producing capacity, increases the risk of enamel demineralization around brackets, and has been identified as a problem in orthodontic treatment. Here, we assessed the risk of biofilm formation by Streptococcus mutans, which is associated with the development of white spot lesions (WSL) on tooth surfaces, using multibracket devices.

METHODS

Various types of brackets were used for the biofilm formation assay with S. mutans coated with human saliva, immersed in renG-expressing S. mutans UA159 (strain with the luciferase gene inserted), and incubated overnight at 37°C under aerobic conditions containing 5% CO2. The biofilm was washed twice with phosphate-buffered saline (PBS), and 200 μL of luciferin dissolved in PBS was added to each well. The mixture was light shielded and allowed to react for 20 min. Luminescence was measured as the amount of biofilm formed by live cells on the bracket surfaces using an optical emission spectrophotometer.

RESULTS

Biofilm formation was greater in plastic brackets than in ceramic and metal brackets in a number-dependent manner. However, biofilm formation was inhibited as the plastic bracket was coated with saliva.

CONCLUSION

For preventive treatments of WSL onset during orthodontic treatment, orthodontists should carefully select and customize brackets based on patient needs, goals, and biomechanical principles. This study developed a new measurement method using renG-expressing S. mutans UA159 to accurately assess active biofilm formation on bracket surfaces.

Does the pain experienced during orthodontic treatment and bracket removal depend on the architecture of the bracket or debonding method?

BACKGROUND

The fear of pain during the various stages of orthodontic treatment with fixed appliances is a common concern of patients. Therefore, the present research aimed to thoroughly investigate the impact of bracket architecture on pain perception during active treatment, debonding, and adhesive removal.

MATERIALS

One hundred consecutive patients who completed treatment with one of two bracket systems (2-slot brackets with an integral base or conventional twin brackets with foil mesh) were included in this prospective cohort study. Participants were asked to evaluate the level of pain encountered throughout their orthodontic treatment with the fixed appliances and during bracket and adhesive removal, utilizing a 0-10 numerical rating scale. Two different methods of bracket removal (bracket debonding pliers and Lift-Off Debonding Instrument) and adhesive removal (adhesive removal pliers and rotary instrument) were tested.

RESULTS

Our study found moderate and comparable levels of pain during active treatment in both groups (4.4 ± 1.6 in the 2-slot group and 3.9 ± 1.9 in the Twin group). Debonding of brackets with integral base caused more discomfort compared to conventional twin brackets and using bracket removal pliers elicited more pain sensations than when Lift-Off Debonding Instrument were employed. Patients are likely to prefer adhesive removal methods involving rotary instruments despite the sound and vibrations produced by contra-angle handpiece.

LIMITATIONS

The lack of randomization in patient grouping introduces an increased risk of bias.

CONCLUSIONS

The results of the present study suggest that the bracket architecture, particularly the construction of the bracket base, affects the level of discomfort experienced during debonding.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT06324162, Registered 20 March 2024-Retrospectively registered, https://clinicaltrials.gov/study/NCT06324162.

Effectiveness of high-frequency vibration, cotton rolls and elastomeric wafers in alleviating debonding pain of orthodontic metal brackets: a randomized clinical trial

This study aimed to evaluate the effectiveness of different pain mitigation methods during orthodontic debonding and to evaluate pain sensitivity across various regions of the dentition. A total of 144 participants (50 males and 94 females) with metal brackets were randomly assigned to one of four groups: High-Frequency Vibration (V), Cotton Roll (CR), Elastomeric Wafer (EW), and Open Mouth group (OM). Pain levels were measured using the Visual Analog Scale (VAS) across different sextants of the dentition. The Kruskal-Wallis test and post hoc analyses were conducted to compare VAS scores between groups. The Mann-Whitney test was used to analyse sex-based differences. The V group, utilizing high-frequency vibration, had the lowest total VAS score, indicating superior pain relief compared to CR, EW, and OM groups. No significant difference was observed between the CR and EW groups. Median VAS scores were highest in the lower front sextant, followed by the upper front sextants, and lowest in the posterior regions, indicating greater pain sensitivity in the anterior regions during debonding. High-frequency vibration was the most effective method for reducing pain during orthodontic debonding, particularly in the anterior dental regions. Both CR and EW methods were also effective but to a lesser extent. These findings suggest that high-frequency vibration could significantly improve patient comfort during orthodontic procedures. Utilizing high-frequency vibration for orthodontic debonding can enhance patient comfort, especially in the more sensitive anterior dental regions, thereby potentially improving treatment compliance and experience.Trial registration: NCT05904587.

Enamel surface roughness after orthodontic adhesive removal: an in vitro study comparing four clearance methods

Purpose

Adhesive remnants removal is the last key step influencing orthodontic treatment outcomes. Four different clearance methods (CM) of orthodontic adhesive were evaluated to determine, which achieved the smoothest enamel surface in the shortest time.

Materials and methods

75 intact premolars extracted for orthodontic purposes were included, sixty had an orthodontic bracket bonded and subsequently removed, and fifteen served as the control group. Four CMs were used to clear the tooth surface of 15 premolars each: carbide bur (CB), carbide bur with titanium nitride surface treatment + fine carbide bur (CBCB), glass fiber-reinforced composite instrument (GFCB), zirconia bur + glass fiber-reinforced composite bur (ZBCB). The processing time was recorded. In ten premolars from each group, the enamel surface was evaluated by atomic force microscopy estimating mean roughness (Ra), roughness profile value (Rq), and roughness depth (Rt). Enamel Damage Index (EDI) was assessed with a scanning electron microscope on 5 remaining premolars.

Results

Significant differences were observed in all evaluated parameters - Ra (p<0.0001), Rq (p<0.0001), and Rt (p<0.0001). GFCB exhibited the smoothest surface in all parameters. The lowest EDI exhibited teeth treated by GFCB, however, the differences were not significant. Working with GFCB took the longest time (mean 116 s), and the shortest with CBCB (mean 49 s).

Conclusion

Using CB is the fastest clearance method, but the enamel surface roughness was highest. Clearing with a set of instruments CBCB proved to be a fast method with satisfying remaining enamel roughness.

Nociceptor mechanisms underlying pain and bone remodeling via orthodontic forces: toward no pain, big gain

Orthodontic forces are strongly associated with pain, the primary complaint among patients wearing orthodontic braces. Compared to other side effects of orthodontic treatment, orthodontic pain is often overlooked, with limited clinical management. Orthodontic forces lead to inflammatory responses in the periodontium, which triggers bone remodeling and eventually induces tooth movement. Mechanical forces and subsequent inflammation in the periodontium activate and sensitize periodontal nociceptors and produce orthodontic pain. Nociceptive afferents expressing transient receptor potential vanilloid subtype 1 (TRPV1) play central roles in transducing nociceptive signals, leading to transcriptional changes in the trigeminal ganglia. Nociceptive molecules, such as TRPV1, transient receptor potential ankyrin subtype 1, acid-sensing ion channel 3, and the P2X3 receptor, are believed to mediate orthodontic pain. Neuropeptides such as calcitonin gene-related peptides and substance P can also regulate orthodontic pain. While periodontal nociceptors transmit nociceptive signals to the brain, they are also known to modulate alveolar bone remodeling in periodontitis. Therefore, periodontal nociceptors and nociceptive molecules may contribute to the modulation of orthodontic tooth movement, which currently remains undetermined. Future studies are needed to better understand the fundamental mechanisms underlying neuroskeletal interactions in orthodontics to improve orthodontic treatment by developing novel methods to reduce pain and accelerate orthodontic tooth movement-thereby achieving "big gains with no pain" in clinical orthodontics.

Deep learning for virtual orthodontic bracket removal: tool establishment and application

OBJECTIVE

We aimed to develop a tool for virtual orthodontic bracket removal based on deep learning algorithms for feature extraction from bonded teeth and to demonstrate its application in a bracket position assessment scenario.

MATERIALS AND METHODS

Our segmentation network for virtual bracket removal was trained using dataset A, containing 978 bonded teeth, 20 original teeth, and 20 brackets generated by scanners. The accuracy and segmentation time of the network were tested by dataset B, which included an additional 118 bonded teeth without knowing the original tooth morphology. This tool was then applied for bracket position assessment. The clinical crown center, bracket center, and orientations of separated teeth and brackets were extracted for analyzing the linear distribution and angular deviation of bonded brackets.

RESULTS

This tool performed virtual bracket removal in 2.9 ms per tooth with accuracies of 98.93% and 97.42% (P < 0.01) in datasets A and B, respectively. The tooth surface and bracket characteristics were extracted and used to evaluate the results of manually bonded brackets by 49 orthodontists. Personal preferences for bracket angulation and bracket distribution were displayed graphically and tabularly.

CONCLUSIONS

The tool's efficiency and precision are satisfactory, and it can be operated without original tooth data. It can be used to display the bonding deviation in the bracket position assessment scenario.

CLINICAL SIGNIFICANCE

With the aid of this tool, unnecessary bracket removal can be avoided when evaluating bracket positions and modifying treatment plans. It has the potential to produce retainers and orthodontic devices prior to tooth debonding.

Effect of Solitaire FR Stent Thrombectomy Combined with the Suction Thrombus on the Clinical Effect and Prognosis of Acute Middle Cerebral Artery Occlusion

To determine the curative effect and prognosis of Solitaire FR stent thrombectomy integrated with the suction thrombus on the treatment of acute middle cerebral artery occlusion (AMCAO). Based on the treatment, patients suffering from AMCAO were separated into the Solitaire FR group (Solitaire FR stent + suction thrombus) and suction group (suction thrombus). Modified thrombolysis in cerebral infarction grading, National Institutes of Health Stroke Scale (NIHSS) score, modified Rankin Scale score, and safety performance were compared between the two groups. The operation time in the suction group was obviously shorter than the Solitaire FR group (P < 0.05). Significant differences were observed in the NIHSS scores 1 week and 4 weeks after the operation between the Solitaire FR group and the suction group (P < 0.05). The NIHSS scores 1 week and 4 weeks after operation were significantly lower than those before operation (P < 0.05). NIHSS scores 1 week after operation did not show obvious difference (P > 0.05). The Solitaire FR group showed obvious lower NIHSS scores than the suction group 4 weeks after surgery (P < 0.05). Statistically obvious difference in cerebral infarction grading of modified thrombolysis between the Solitaire FR group and the suction group were observed (P < 0.05). The recanalization rate of the Solitaire FR group was obviously higher than the suction group (P < 0.05). The difference in the monthly modified Rankin Scale score was obvious (P < 0.05). The good prognosis rate of the Solitaire FR group was obviously higher than the suction group (P < 0.05). No obvious differences in the incidence of internal bleeding, reocclusion, and 3-month postoperative mortality were observed (P > 0.05). These results showed that the treatment of the Solitaire FR stent + suction thrombus in AMCAO patients has a good thrombus recanalization rate and is helpful in improving the prognosis and safety performance.

Do different orthodontic pliers used in bracket debonding have different effects on pain and sensitivity? A prospective split-mouth study

OBJECTIVES

The assessment of whether different orthodontic pliers used in bracket debonding have different effects on pain and sensitivity experience.

MATERIALS AND METHODS

Thirty-three patients (17 females, 16 males) with metal brackets were included in the study. Compressed air and freshly melted ice water were applied to each tooth (6-6) in upper and lower arch before bracket debonding (T0), just after debonding (T1), and 1 week after debonding (T2). Bracket remover plier (BRP) and Weingart plier (WP) were used to debond brackets. A numeric rating scale (NRS) was used to assess sensitivity for each tooth at T0, T1, and T2. Tooth pain was assessed for each tooth using NRS during bracket debonding.

RESULTS

Statistically higher pain scores were found in teeth U4 (upper first premolar) (p = 0.017) and L6 (lower first molar) (p = 0.026) in Weingart plier group. No statistically significant difference was found during debonding in the other teeth between groups. Statistically high sensitivity score was found at T1 time point in tooth U3 (upper canine) by applying air stimulus in Weingart plier group (p = 0.024). There was no statistically significant difference between the sensitivity scores measured at T2 time point by applying air and cold stimuli between groups.

CONCLUSIONS

Although the debonding pain scores were statistically significant in two teeth and the sensitivity score in one tooth, there was no clinical significance between the two pliers in terms of pain and sensitivity.

CLINICAL RELEVANCE

Both debonding pliers gave clinically similar results in terms of pain and sensitivity.