A randomized clinical trial design was employed to assess the effectiveness of high-frequency vibration in reducing debonding pain compared to other methods. Additionally, the study explored the influence of sex and location of the dentition on pain perception.
This study utilized simple randomization with a random code generator and ensured allocation concealment to avoid selection bias and increase the generalizability of the study findings. To avoid performance bias and increase the objectivity, reliability, and credibility of the study, patient blinding was implemented. Participants were not informed about the potential effectiveness of any of the pain management methods used in the study. Instead, they were instructed to report their pain scores based solely on their subjective experience during the debonding procedure. This approach aimed to minimize any preconceived notions about the effectiveness of the methods, thereby that the pain scores accurately reflected the participants’ genuine pain experiences.
There was no attrition bias in this study, as there were no drop outs. consequently, the statistical power was increased to 86% and the ability to detect meaningful differences between groups was maintained. All outcomes were measured, analysed, and reported, which supports the conclusion that the study had a low risk of reporting bias.
The sex-based comparison of VAS scores using the Mann–Whitney U test revealed no significant differences. It is worth noting that, despite the lack of statistical significance, females reported higher pain scores across the entire dentition.
The GAD-7 questionnaire was selected for its simplicity and reliability in measuring anxiety levels, as endorsed by multiple scholars28,29,30. By utilizing the GAD-7 as a criterion for participant selection, the study aimed to identify individuals with generalized anxiety disorder (GAD), a condition associated with heightened pain perception in previous research31,32. According to Spitzer et al. (2006), a GAD-7 score of 10 or higher indicates moderate anxiety, while scores from 5 to 9 suggest mild anxiety33. For this study, participants with scores of 7 or lower were recruited, specifically chosen from the lower half of the mild anxiety range to minimize potential confounding effects of elevated anxiety on pain perception. The impact of this criterion was reflected by having a very weak and non-significant correlation between GAD-7 scores and VAS scores for the whole dentition; in other words, the impact of anxiety on the measured pain scores was minimized.
VAS was selected due to its reduced susceptibility to individual beliefs or distress and its ability to provide a more comprehensive assessment of pain intensity compared to other scales34,35. It’s important to note that the potential variability in patient-reported outcomes due to the subjective nature of pain assessment cannot be entirely eliminated, even when using the VAS.
In this study, the angled bracket remover plier was specifically chosen for the debonding process because of its versatility in accessing both anterior and posterior regions of the dentition. This decision ensured consistency in instrument use throughout the study and is supported by its widespread acceptance and use for debonding orthodontic brackets in previous studies12,16,18,20,36. To minimize interoperator variability, a single operator (AIM) performed all debonding procedures using the same designated technique for all the study participants. The single-operator design, minimizes interoperator variability, but it introduces the risk of operator bias. The uniformity of the debonding technique across all participants is a strength, but it also means that any unconscious biases or variations in technique by the operator could have systematically influenced the results. To mitigate this risk, the study employed a sufficiently large sample size, which helps to reduce the impact of individual operator bias on the overall findings.
The influence of external factors, such as the environment in which the debonding procedures were performed, cannot be entirely ruled out. To address this, several measures were implemented to standardize conditions across all recruitment centres. Each establishment was equipped with a designated dental chair specifically for the study, and all debonding procedures were conducted between 9:00 and 11:00 p.m. to minimize the impact of circadian rhythms on pain perception. These steps were implemented to ensure a more consistent and accurate evaluation of the pain management methods.
Utilizing CR or similar materials to provide an intrusive force during debonding has been advocated in literature due to their effectiveness in addressing occlusal variations. Although Celebi et al. (2021) did explore the CR method13, direct comparisons with our study may not be entirely suitable due to differing methodologies. Their split-mouth design raises concerns about potential carry-over effects37. Hence, a more robust study design was chosen to assess the CR method potential for pain reduction.
Bavbek et al. (2016) found that finger pressure was more effective than EW in reducing debonding pain. Notably, this conclusion was reached after adjusting the VAS scores; before the adjustment, there was no significant difference between the pain control methods. This discrepancy could be attributed to the small sample size (21 participants per group), which may have limited the reliability of the initial results12. In contrast, Iqbal et al. (2023) reported that biting on an EW reduced debonding pain more effectively than finger pressure38. This discrepancy may stem from variations in the thickness of the wafer used, Iqbal et al. folded the wafer four times before employing it for biting and also included a larger sample size (55 participants per group) in their two-arm study. Therefore, there is a need to assess the effectiveness of EW and compare it to that of the CR, as both methods aim to alleviate debonding pain by applying simple intrusive force.
In orthodontics, vibration devices are categorized by frequency: low-frequency (≤ 45 Hz) and high-frequency (≥ 90 Hz). The AcceleDent device operates at a low-frequency, while the VPro device functions at high-frequency39. Vibration analgesia, as described by Hollins et al. (2014)40, involved using vibration to alleviate pain. As vibration was shown to reduce pain41. Casale and Hansson (2022) noted that high-frequency vibration align well with the gate control theory because it activates large-diameter A-β fibers, which are non-noxious mechanoreceptors and transmit impulses quickly due to their myelination. When these fibers are stimulated, they produce an inhibitory response that can close the “pain gate,” preventing pain signals from being sent to the brain. This results in a reduction of pain sensation26. In contrast, low-frequency vibration are less effective at stimulating A-β fibers and therefore do not have the same analgesic effect. In contrast, low-frequency vibration are more likely to increase motor output rather than modulate pain42.
Jayapal et al. (2020) found that low-frequency vibration from the AcceleDent device reduced debonding pain21. Conversely, high-frequency vibration has also been effective in pain reduction during orthodontic treatment, as concluded in the latest meta-analysis by Li et al. (2024)25. Given the documented efficacy of high-frequency vibration and the lack of research on its use for debonding pain, the VPro device was selected for this clinical trial.
Regardless of the method used, median VAS scores were highest in the lower anterior sextant, followed by the upper anterior sextants, and lowest in the upper and lower posterior regions. The increased VAS scores in the anterior region suggest that this area of the jaw is more sensitive to pain during debonding, a finding corroborated by previous studies2,18,43,44,45,46. The tactile sensory threshold of the anterior region is 1 g compared to 5 to 10 g in the posterior region of the dental arch16. This heightened sensitivity could be attributed to the anatomic location and root morphology of teeth in these regions. Teeth in the upper and lower anterior sextants typically have a single root with less surface area and are housed in a thinner cortical boundary, making them more susceptible to force during debonding compared to multirooted teeth in the posterior sextants, which are housed in a thicker cortical boundary2.
Notably, the VAS scores for the anterior region were the lowest when using the high-frequency vibration method compared to other methods. The V method showed a reduced VAS scores by 10–15 points as compared to other methods, which highlights its clinical significance22. Statistically significant differences in VAS scores were observed across various areas of the dentition among all groups. The intergroup comparison revealed that the V group had the lowest VAS scores compared to the other groups. It demonstrated a statistically significant difference in pain reduction in the anterior region as compared to the CR and OM methods. The V method had significantly lower VAS scores for the upper and lower dentition as well as the whole dentition. This suggests that the V method could be more effective for pain management than CR and EW methods.
Furthermore, significant differences in VAS scores were observed between the CR-OM group, and EW-OM group for the total dentition, indicating that these methods can be used to alleviate pain. However, there was no significant difference in VAS scores between the CR and EW groups, which suggests that they may be equally reliable in pain management during debonding.
The V method is a user-friendly and efficient approach to pain control. However, the requirement for specialized equipment may limit its availability in all orthodontic clinics. The CR and EW methods function by applying an intrusive force to the incisal or occlusal surface of the tooth. This could stabilize the tooth and mitigate the torsional and peeling forces exerted on the periodontal ligament during debonding. Additionally, these methods provide a proprioceptive stimulus that is thought to alleviate pain based on the gate control theory. Although the CR and EW methods were statistically equivalent in effectiveness, the CR method’s lower VAS score and its widespread availability could make it serve as a viable alternative to the V method.
Limitations
A potential limitation of the study is its focus on a specific ethnic population (Iraqi Arabs), which may limit the generalizability of the findings to other populations or clinical settings. Ethnicity has been shown to influence pain perception47,48, Additionally, variables such as bracket type (manufacturer) and adhesive type were not accounted for. These factors could potentially confound the study results, warranting caution when interpreting and extrapolating findings to broader populations or clinical contexts.