The Two by Four appliance: a nationwide cross-sectional survey.

Aim: The aim of the study was to investigate how widespread is the use of the 2 x 4 appliance among Italian general dentists and specialists in orthodontics, as well as the type of treatment employed and length of use.

Materials And Methods: We conducted a nationwide cross-sectional survey from July 14, 2016 to January 12, 2017 using an online questionnaire of 8 multiple choice questions, created by the SurveyMonkey® Company, on a population of Italian dentists and specialists in orthodontics affiliated with the Italian Society of Paediatric Dentistry (SIOI). This was made to assess how many clinicians knew and used this device in their clinical practice. We included 200 Italian dentists, 99 specialists in orthodontics and 101 general dentists of a mean age of 45 ± 15 years.

Results: Results show that 93.94% of orthodontists have knowledge of and use this device in their clinical practice, while only 51.49% of the general dentists have knowledge of and use it (p<0.001). The 51.92% of dentists and the 52.13% of orthodontists used the 2x4 appliance to treat both space management and incorrect overjet. Most of general dentists and orthodontists combined the 2x4 appliance with pre-adjusted brackets and accessory components such as coil springs and power chains. While most of dentists (45.90%) used the 2x4 in association with appliances for space management, most of specialists (46.15%) applied the 2×4 in combination with both appliances for space management and high-pull headgear. Statistically significant differences were found also for the answers to the question "what is the average time of treatment?" among general dentists: the 32.79% used the 2 x 4 for less than 6 months of treatment, and the 67.21% used the 2 x 4 for more than 6 months of treatment. On the other hand 49.46% of orthodontists used the 2 x 4 for less than 6 months of treatment, and 50.54% of them for more than 6 months of treatment (p=0.041).

Conclusions: We conclude that the 2 x 4 appliance is widespread among orthodontists and about half of the general dentists, 93.94% and 51.49% (p<0.001) respectively. We found that 67.21% of general dentists used the 2 x 4 for a more than 6 months of treatment. As far as the orthodontists, 49.46% used the device for less than 6 months of treatment and 50.54% of them for more than 6 months of treatment. These differences were statistically significant (p=0.041).