Journal of Aligner Orthodontics, 01/2020

Objectives: The main goal of the present study was to find whether the use of nearly invisible aligners together with vibratory stimulation was able to shorten the lag times between aligner exchanges, reduce the number of refinements and thus reduce the total treatment time. Materials and methods: The study included 66 successive participants who gave agreement to specific treatment protocols. Each treatment included the use of aligners for durations shorter than those recommended by the manufacturer together with daily vibratory stimulation. The purpose of the analysis was to search for the: i) number of aligners used; ii) number of refinements required; iii) duration of aligner wear; iv) total treatment durations. Results: The protocols resulted in: i) a reduction of the expected number of refinements (less than two in 51 cases); ii) a reduction of the expected durations of aligner wear; iii) 60%, 44% and 20% reduction of the total treatment duration in aligner exchange series initially scheduled at 14-, 10- and 7-day intervals, respectively; this corresponded to median gains of 14, 7 and 2 months over the expected total treatment durations (P 0.001). Conclusion: The combination of nearly invisible aligners with vibration was able to shorten the lag times between visits. This was likely to have alleviated the workload of dental clinics per patient and increased patient satisfaction, at least with the total treatment duration. Keywords: AcceleDent Optima, accelerated osteogenic orthodontics, clear aligners, Invisalign system, orthodontic aligners, vibration

Background: In aligner orthodontics the relationship be- tween movement per step, material properties and generated forces is not immediately obvious. In complex cases, the attachment level of periodontally impaired teeth as well as the attachment shape and position must also be considered. Thus, one way to learn more about these conditions is to gain experience from daily clinical practice, the other way is to examine various situations in vitro. In the course of scientific investigations, several sophisticated devices have been developed using high-precision industrial three-axis force and moment sensors. The high costs of the sensors and the complexity of the interaction between software and hardware constitute an obstacle for extensive use in the educational area. Objective: To develop a low-cost sensor system for orthodontic force measurement for educational purposes. Material and methods: A simple, open source apparatus for three-axis force measurement using load cells is presented here. Comprehensive information about software and hardware as well as details about measurement quality are also presented. Additionally, an example illustrating the results derived from an experimental setup with intrusion/extrusion of a central incisor is also given. Results: The results of the calibration process and error measurement showed that it was possible to assemble an adequately accurate (ICC ≥ 0.999) device. The Dahlberg error was under 0.3 g, sensor readouts were linear and repeated measurements were accurate enough for the desired purpose. The measurement example demonstrated that it was possible to simulate a clinical situation. Conclusion: The presented apparatus may be a good starting point for further educational projects. Keywords: 3D printing, aligner, DIY, force measurement

The development of digital technology contributes to the diagnosis, treatment and therapeutic outcome analysis in orthodontics. The present case describes a female patient with a protrusive profile who sought clear aligners orthodontic treatment. She was skeletal Class II with maxillary protrusion and mandibular retrusion. The extraction of two maxillary first premolars and interproximal reduction of the mandibular anterior teeth were used to correct the situation. An incisors retraction was performed to improve the horizontal overlap. The anterior teeth were lowered to improve the patient's vertical overlap. After 28 months of orthodontic treatment, the patient convex facial profile was improved, and a normal horizontal overlap and vertical overlap were achieved. Keywords: clear aligners, digital model superimposition, digital technology, skeletal Class II

Clear aligner treatment has significantly improved throughout the last decade and is recommended for more complicated orthodontic treatment. However, torque movement is still challenging when achieved by clear aligners. In this case report, a 20-year-old patient who underwent orthodontic treatment during childhood, retained by a mandibular canine- to-canine fixed retainer, was referred to the clinic by a periodontist. Her mandibular right lateral incisor (tooth 42) was torqued in, and central incisor (tooth 41) was torqued out with a reciprocal torque difference. A 4-mm lingual recession and 6-mm labial recession was attributed to retainer-caused inadvertent tooth movement. Torque differences were also demonstrated on the maxillary central incisors (tooth 11 and tooth 21). An orthodontic correction of axial inclination of mandibular incisors and movement to their normal positions was planned. The patient was scheduled for periodontal free-gingival graft on the central incisor, post-orthodontic treatment. Within 18 months, the treatment with clear aligners, interproximal reduction and Class III elastics was successful, resulting in torque correction of teeth 41 and 42, and alignment of the dental arch teeth. Torque of teeth 11 and 21 was achieved. Fixed retainers were fabricated for six maxillary and mandibular anterior teeth combined with Essix nightwear retainers for long-term stability. A dead-soft passive wire was chosen to avoid retainer-caused complications. The graft surgery was postponed due to improved prognosis of the mandibular central incisor, significant reduction in gingival recession and the presence of a thin layer of keratinised gingiva. Orthodontists, general dental practitioners and patients should be aware of the possible complications of fixed retainers and orthodontic correction. Keywords: clear aligners, fixed retainer, free graft, gingival recession, Invisalign, mandibular incisors inclination, orthodontics, torque

In this issue of the JAO we have asked our affiliated scientific societies to provide their details, mission statements and board members, to help readers discover more about each group's work in the field of aligner orthodontics