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

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.