Effectiveness of the NOLA Dry Field device as an isolation system for bonding lower lingual retainers

The retention stage has been the most controversial phase of orthodontic treatment, as there are no specific guidelines regarding the type, mode and duration of retention. The detachment of a retainer creates urgency, necessitates additional consultation time and increases the risk of tooth movement. Therefore, ensuring the stability of a retainer and preventing detachment is crucial, particularly as saliva moisture poses a risk during bonding.

This pilot study employs an epidemiological, observational, descriptive and longitudinal design to compare the failure rates of lower lingual retainers cemented with the NOLA retractor against those cemented with the Spandex retractor. The sample comprised 32 participants, with 16 each in the NOLA group and the relative isolation group. The NOLA group included 10 men (62.5%), while the isolation group had only 3 men (18.7%). The normality of the data was assessed using the Shapiro-Wilk test, and the Student's t-test was applied to compare changes between the NOLA and relative isolation groups.

The failure rate was higher in the relative isolation group (37.5%) compared with the NOLA group (25.0%), although this difference was not statistically significant (p = 0.446). A progressive and significant increase in the Little's Irregularity Index values was observed in both groups over time. While there was a greater increase in values in the NOLA group, the difference did not reach statistical significance (p = 0.108 at 3 months and p = 0.284 at 6 months).

Both isolation methods demonstrated similar success rates in retaining fixed retainers over the analysed time period. Key words:Orthodontic Retainers, Fixed Orthodontic Appliance, Removable Orthodontic Appliances, Periodontal Index.