Fares Alshuraim, Christopher Burns, Darren Morganb, Luay Jabrb, Paul Emile Rossouw, Dimitrios Michelogiannakis
What did the authors aim to do in this study?
The primary aim of this study was to compare the orthodontic treatment (OT) outcome in adolescents undergoing non-extraction fixed OT with or without bonding of second molars using the score of the ABO's Cast Radiograph Evaluation (C-R-Eval).
How did the authors evaluate?
In this retrospective study, healthy adolescents with skeletal Class I or mild Class II/Class III malocclusion, normal or deep overbite (OB), and mild-to-moderate dental crowding (0.5 mm) who underwent non-extraction fixed OT were divided into two different groups as follows:
- “Bonded” group: Patients who received comprehensive full-arch fixed OT including bonding of maxillary and mandibular permanent second molars during the first 2 months of OT.
- “Not-bonded” group: Similar to bonded group, except that permanent second molars were not bonded during fixed OT.
All the patient's treatment records, pre- and post treatment digital models, lateral cephalograms, and orthopantomograms were assessed. The evaluated outcomes included the leveling of the curve of Spee (COS), OB, control of incisor mandibular plane angle (IMPA), number of emergency visits (related to poking wires and/or bracket failure of the terminal molar tubes), treatment duration, and C-R-Eval. All the treatment variables were compared across time points and among groups.
The statistical analysis was carried out by using the Independent and the paired - sample t -tests.
Table 1. Baseline malocclusion-related characteristics between study groups.
What did the authors find?
The sample included 30 patients in the bonded group and 32 patients in the not-bonded group. The mean overall C-R-Eval score was significantly higher in the not-bonded group than in the bonded group. There were no significant differences in mean changes of COS, OB, IMPA, or treatment duration among groups. The mean number of emergency visits was significantly higher in the bonded than the not-bonded group. The ABO C-R-Eval was adopted in this study as an indicator of the OT outcome as it has been well-established as a standardized and objective approach to assess OT outcomes, grade clinical case reports, and facilitate comparative analysis. The C-R-Eval combines variables that contribute toward the success of OT, including the alignment, buccolingual inclination, overjet, occlusal contacts, occlusal relationships, marginal ridges, interproximal contacts, and root parallelism.
The authors incorporated the measurements of OB, leveling of COS, and control of IMPA in the main study outcomes as they are intertwined with a functional and stable occlusal outcome and are not integrated in the C-R Eval score. Treatment duration and number of emergency visits were recorded to incorporate parameters of treatment efficiency and patient satisfaction. Bonding of the second molars during the initial phase of OT yielded a superior OT outcome, as documented by the significantly lower overall mean C-R-Eval score in the bonded than in the not-bonded group. This improvement did not lead to a prolonged treatment duration, as the mean duration of OT was comparable among groups. Comparison of the C-R-Eval total scores and scores from the second molars only per individual categories revealed that most significant differences among study groups were attributed to improved positioning of the second molars in the bonded group. Until recently, the belief that bonding the second molars improves OT outcomes remained largely anecdotal.
What did the authors conclude?
• It was concluded that the bonding of second molars enhances the outcome of non-extraction fixed OT as demonstrated by C-R-Eval, without increasing the treatment duration.
• An increased number of emergency visits might be expected in adolescents, who are undergoing the fixed OT with bonded second molars.
What do we think about it?
One of the dilemmas a clinician has whenever they start off orthodontic treatment in a patient is, if we need to bond the second molars or not. This decision is always influenced by numerous factors such as the treatment approach, appliance selection, and the decisions made during treatment. Other treatment factors that potentially influence the effectiveness of the treatment include the bracket slot size, mechanics used in space closure, type of ligation, the type of wires & the sequence of wires used. Inspite of all these factors, in orthodontics, this decision is purely taken according to the clinician's preference & beliefs. So, this particular study included & compared all the possible factors that influence this decision. Although the study did have limitations, such as the study sample selected was a retrospective convenience sample, so this limits the generalizability of the results. Also, the study had the risk of a selection bias that could not be ignored. But, overall the study helped understand the advantages that the second molar inclusion had in patients, because it included the analysis of numerous factors that influence the orthodontic treatment outcome, which guides the clinician to make an evidence based decision.
Alshuraim F, Burns C, Morgan D, Jabr L, Rossouw PE, Michelogiannakis D. The second molar dilemma in orthodontics: to bond or not to bond? Angle Orthod. 2024 May 1;94(3):320-327.
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