Using high-frequency vibration in orthodontic retention
Retention can be a frustrating process for orthodontists and patients alike. Relapse occurs for many reasons, ranging from patients who don’t replace their broken retainers to those who are simply noncompliant. Studies have shown that 40 percent to 90 percent of orthodontic patients have unacceptable dental alignment 10 years after treatment.1 Based on these statistics, there’s certainly room for improvement in this important aspect of orthodontic treatment. Therefore, when choosing our retention strategy and appliance, basing it on the individual and retention science can contribute to preserving a lasting and stable occlusion.
One of the reasons retention is difficult to maintain is because of the length of time it takes for the teeth to be adequately “settled” in their new positions. Pratt et al. noted that while retention varies based on tissue types, generally reorganization of the periodontal ligament occurs over three to four months, the gingival collagen–fiber network takes approximately four to six months to remodel, and the elastic supracrestal fibers remain deviated for more than seven months. The article notes that this reorganization phase is completed usually within a year of debonding.1
Bone-density changes occur during and after orthodontic treatment, as well. Yu et al. noted a 23 percent reduction in bone-mineral density around treated teeth after a seven-month period of active orthodontic treatment. After a two-year retention period, most patients’ alveolar bone density recovered; however, bone density around approximately 10 percent of teeth failed to recover to even 80 percent of its pretreatment state.2 This stresses the importance of the second phase: post-retention, lasting for the rest of the patient’s life.
Though still a relatively new orthodontic 
The lack of awareness of clear aligners’ benefits among dental practitioners has sometimes been attributed to a lack of scientific studies on this treatment modality. As aligner therapy has developed and been more widely adopted, however, increasing research into its effectiveness and patient satisfaction rates has been conducted. For example, a 2015 study published in the BMC Oral Health journal compared oral health status and satisfaction levels among patients who had received fixed appliances and those treated with the Invisalign system. It found that Invisalign patients were more satisfied overall and enjoyed greater periodontal health, with slightly lower levels of dental plaque. According to another study, conducted in 2013 and published in The Angle Orthodontist journal, compared with those treated with conventional edgewise brackets, patients who had received aligner therapy had significantly fewer dental visits, shorter treatment duration, fewer emergency visits and less overall chair time.
