Incidence of orthodontic brackets detachment during orthodontic treatment: A systematic review

Objectives: To evaluate the incidence of orthodontic brackets detachment during orthodontic treatment. Methods: Using electronic databases; eligible studies up to January 2018 were retrieved, independently reviewed, and screened. The Coleman Methodology Scoring System (CMS) and Cochrane Collaboration’s tool were used to assess quality and risk of bias in the included studies. Results: Of the seventeen studies included in the final synthesis, thirteen were categorized as randomized clinical trials (RCTs), one prospective cohort and retrospective survey each, whereas two studies could not be categorized. The number of patients in the selected studies ranged between 19 and 153; the mean age was between 10.5 to 38.7 years, and male to female ratio was 353:495. Almost all studies had a high risk of bias, and more than half of the studies had CMS score of 70 or above. The numbers of brackets examined in the studies ranged between 361 and 3336. The incidence of brackets detachment ranged from 0.6 to 28.3%. Conclusions: The incidence of brackets detachment during orthodontic treatment is high.


INTRODUCTION
Orthodontic treatment enhances patients' physical appearance by correcting malocclusion of teeth. The treatment also improves oral health conditions that are related to malocclusions. These conditions include, mastication difficulties with potential to cause digestion problems, speech impairments, abnormal loading of temporomandibular joints that can lead to severe inflammation and pain, headaches or pain in the patients' face and neck.
Orthodontists use various removable and fixed appliances to treat orthodontic problems. The main components of the fixed orthodontic appliances are brackets that are attached to the teeth using different types of adhesives. The movement of teeth depends on the wires and springs attached to these brackets. Therefore, it is of utmost importance that these brackets remain attached to the teeth during the course of orthodontic treatment. However, brackets detachment "debonding" from the teeth remains one of the major concerns during orthodontic treatment with fixed appliances. [1][2][3] The bracket bonding procedure plays a major role in achieving an optimal outcome during orthodontic corrective procedures, as the required tooth movement relies upon it. 4 Bracket detachment during corrective procedures may also lead to increased treatment duration, damage to tooth enamel, and increased chairside-time due to re-bonding procedure. 2,3 Consequently, it could also raise the costs of the overall orthodontic treatment. 4 Recent advancements in dental materials and bonding techniques has helped to make orthodontic brackets bonding easier, efficient, predictable, and effective. 6 Orthodontic bonding technique has changed significantly since it was first used in 1950s. 7 At present, there are direct and indirect bonding techniques used in orthodontic treatment with fixed appliances. 8,9 However, both the techniques have advantages and disadvantages in relation to bond failure rates. [10][11][12] Although indirect bonding technique has more advantages in terms of shorter initial bonding appointment, higher degree of precision, and more focused results, yet the majority of the orthodontists prefer the direct bonding technique to avoid laboratory involvement. 13 Bracket detachment is a major concern during orthodontic treatment with fixed appliances, as it can be irritating and in some instances critical in the overall success of the treatment. Presently, there is a tendency towards bonding brackets on all the teeth for providing full arch orthodontic treatment, thus making bracket detachment more critical. [14][15][16] Previous studies have reported varying incidence of bracket failure following orthodontic brackets bonding. 17,18 Several studies have also compared various techniques of orthodontic bonding and rates of brackets failure. [19][20][21][22][23][24][25][26][27] However, there are no systematic reviews available on incidence of orthodontic brackets detachment during orthodontic treatment. Therefore, the current study aimed to summarize the evidence regarding the incidence of orthodontic brackets detachment during orthodontic treatment.

Search Strategies:
The electronic databases, PubMed and Web of Science were searched from their inception up to January 2018. Only studies published in the English language were included. The databases were searched using the following keywords: ("Orthodontic treatment" OR "Dental procedures") AND ("Brackets detachment" OR "Bracket debonding" OR "Bracket bonding" OR "Bracket failure") AND ("Prevalence" OR "Incidence"). Additionally, the studies were searched manually from the reference lists of the studies identified through databases. Study Selection: All the studies investigating brackets detachment during orthodontic treatment with fixed appliances were included. Studies were required to report the incidence of brackets failure as one of the study outcomes. Data Extraction: Both authors independently screened the titles and abstracts to exclude irrelevant articles. Full texts of the potential articles were then evaluated to identify eligible studies. Following data were extracted from the included studies: author(s), year of publication, study design, bonding technique used, total number of brackets used, number and incidence of bracket failure, and conclusions. Both authors discussed and reached to an agreement on various items of the collected data. Quality Assessment: Both authors evaluated the quality of all the selected studies using the Coleman Methodology Scoring (CMS) system. 28 The CMS has ten sections with a total of 100 points. Additionally, the Cochrane Collaboration's tool was used to assess the risk of bias in the included studies. Risk of bias was presented as low, unclear, or high for the each included study. 29 Both the authors discussed and reached to an agreement on the quality assessment. Outcome Measure: The outcome evaluated in this systematic review was the incidence of brackets detachment during orthodontic treatment with fixed appliances.

Study Selection:
Based on the titles and abstracts, 222 articles were initially identified. After excluding duplicates and screening the abstracts, 189 studies were not found relevant to objective of this review. Further sixteen articles were excluded due to not matching the inclusion criteria. Therefore, a total of seventeen studies were included in the final synthesis. 1,4,[20][21][22][23][24]27,[30][31][32][33][34][35][36][37][38] The inter-assessor agreement was very good to excellent for initial screening and full-text eligibility (k = 0.81 and 0.94 respectively). Figure 1 presents details of study selection process and results of the literature search as per PRISMA guidelines. 24 Characteristics of Included Studies: Table-I   Only two studies 1,38 had CMS score of 50%. Two of the studies provided the justification for sample size and provided information about drop outs from the study. 22,27 None of the included studies reported the clinical importance of the results (Table-II). Risk of bias is presented as a graph in Figure 2. Almost all the included studies had a high risk of bias, 1,4,[20][21][22][23][24][30][31][32][33][34][35][36][37][38] while only one study had an unclear risk of bias. 27

DISCUSSION
As per our knowledge, this is the first systematic review on the incidence of brackets detachment during orthodontic treatment. An increase in incidence of bracket failure is expected with increase in the follow-up period. However, this was not evident from the results of the current review. Only one study reported very high incidence of brackets detachment (28.3%), 22   Out of the seventeen studies included in this review, eight studies 1,4,21,33,35-38 had low CMS score (≤ 60%), which indicates low methodological quality. Various items were not met by most of the included studies, therefore, future studies investigating incidence of brackets detachment after orthodontic treatment considering these items are recommended. The lack of information about the sample size estimation and dropouts could  limit the validity of the results. Additionally, a lack of information about the patient's description could also limit the generalizability of results.
Of the seventeen studies included in this review, almost all the included studies had a high risk of bias, 1,4,20-24,30-38 while only one study had an unclear risk of bias. 27 Several items including allocation concealment and blinding of participants, personnel and outcome assessor were not met by most of the included studies. A previous study has reported the importance of blinding to reduce the performance and detection bias. 39 Limitations: It was heterogeneity among the studies as related to patients' selection criteria, treatment techniques, outcome criteria, and length of follow-up, indicating lack of sufficient body of literature available on this topic. The present review did not assess the factors associated with brackets detachment during orthodontic treatment. Nevertheless, the present review has provided new evidence-based information on incidence of bracket failure during orthodontic treatment. Orthodontists need to adopt all the possible measures to prevent bracket failure during treatment with fixed orthodontic appliances.