What Biases Might Exist in In-Office Aligner Treatments?

In-office aligner treatments (performed and managed directly in the dental or orthodontic office) can involve several types of biases that could affect the results and evaluation of the treatment's effectiveness. Here are some of the biases that might be present in this context:

1. Selection Bias

   • Description: This bias occurs when the patients selected for in-office aligner treatment are not representative of the general population. It may be that only simpler cases or those perceived as more suitable for treatment are chosen, which could lead to an overestimation of the treatment's effectiveness.

   • Example: An orthodontist might select patients with mild or moderate malocclusion for aligner treatments, while more complex cases are treated with other methods, which could bias the results toward a higher success rate with aligners.

     
     

2. Confirmation Bias

   • Description: The orthodontist might interpret the treatment results with aligners in a way that confirms their prior expectations or beliefs about the method's effectiveness.

   • Example: If the orthodontist has a strong belief in the efficacy of aligners, they might be more inclined to see and report positive outcomes, even when the result is suboptimal or when there are limitations in the dental movement being attempted.

     
     

3. Observer Bias

   • Description: The evaluation of the treatment results may be influenced by the orthodontist's expectations. If the orthodontist knows that the treatment was carried out with in-office aligners, they might be more likely to evaluate the results positively due to their direct involvement in the process.

   • Example: The orthodontist might interpret a moderate improvement in dental alignment as a complete success of the treatment due to a positive expectation bias toward aligners.

     
     

4. Performance Bias

   • Description: Patients and the orthodontist may behave differently knowing that the treatment is being carried out in-office. This can include greater patient commitment to using the aligners or a higher degree of customization and adjustment of the treatment by the orthodontist.

   • Example: Patients might be more diligent in using their aligners correctly knowing they are being closely monitored by the orthodontist, which might not reflect the typical use of aligners in a less controlled environment.

     
     

5. Measurement Bias

   • Description: The results of the in-office aligner treatment may depend on the tools and evaluation methods used, which may not be completely objective or standardized.

   • Example: The evaluation of improvement in dental alignment might be based on visual impressions or dental models, which can be subjective and vary according to the orthodontist's criteria.

     
     

6. Publication Bias

   • Description: Successful cases of in-office aligner treatments are more likely to be published or presented at conferences, while less successful cases might not receive the same attention.

   • Example: An orthodontist might prefer to showcase only successful cases to colleagues and in publications, giving a more positive image of the effectiveness of aligner treatment than what is actually the case in everyday practice.

     
     

7. Attrition Bias

   • Description: If there is a loss of patient follow-up during treatment (e.g., if patients drop out of treatment or do not comply with follow-up visits), this could influence the evaluation of the results.

   • Example: Patients who experience difficulties or unsatisfactory results may be more likely to drop out of treatment, and if these dropouts are not considered in the final evaluation, the reported results might appear more favorable.

     
     

8. Information Bias

   • Description: The information provided to patients about the treatment and its follow-up can influence their perception and behavior, affecting the results.

   • Example: Patients who receive very positive explanations about the ease and effectiveness of aligners might be predisposed to report more favorable experiences and outcomes, even if they encounter difficulties.

     
     

Conclusion In-office aligner treatments can be subject to various biases that can influence the perception and evaluation of their effectiveness. These biases can affect both the selection of patients and the interpretation of the results and the way they are presented and reported. It is important for orthodontists to be aware of these biases and adopt measures to minimize them, such as standardizing selection criteria, ensuring objectivity in the evaluation of results, and transparently reporting both successful and unsuccessful cases. Understanding and controlling these biases are essential for an accurate and fair assessment of aligner treatments.