Journal of Aligner Orthodontics, 04/2021

Artificial intelligence is now firmly established in society. Whether we are searching on Google (Mountain View, CA, USA), being guided by recommendation algorithms or using facial recognition or smart home software, artificial intelligence is a daily presence in our lives, and in almost all areas: business, science, medicine, and increasingly in orthodontics. What is artificial intelligence, what does it encompass, what can it already do in orthodontics and where is it taking us in the discipline? What opportunities does it offer and what negative effects does it have? In this article, the first in a three-part series, we will discuss these questions and strive to answer them. Keywords: aligner orthodontics, artificial intelligence, convolutional neural networks, deep learning, machine learning, neural networks

All orthodontic therapies are only effective when carried out in conjunction with systematic preventive dentistry. The latter must be based on the work of Axelsson and Lindhe. Both domestic and professional oral hygiene measures are critical to maintaining oral health and preventing therapy-related damage to dental hard substances and soft tissues. The systematic prevention workflow must be based not only on dental biofilm management, but also on the patient’s complex medical and dental conditions. Keywords: adult orthodontics, biofilm, periodontal disease, preventive dentistry

Objective: To compare the orthodontic forces delivered by aligners with regard to the amount of activation, material type and time, and to determine the influence of beverages and nicotine on these forces. Materials and methods: An experimental study was conducted on 120 aligners made of polyethylene terephthalate glycol and polyurethane. The study environments included room temperature without immersion, artificial saliva (Gum Hydral gel, Sunstar, Etoy, Switzerland), Coca-Cola (Coca-Cola Company, Atlanta, GA, USA), coffee (Nescafé Original, Nestlé, Vaud, Switzerland), white wine (La Vague, Cave de Bir Drassen, Bir Drassen, Tunisia) and nicotine liquid (Nicoboost 20mg/ml PG50/VG50, Readiy, Le Cannet, France). The forces were measured using a thin film pressure sensor (Force-Sensitive Resistor [FSR] – Small SEN-09673, Interlink Electronics, Camarillo, CA, USA). Results: The forces delivered by aligners increased significantly as the amount of activation increased. Polyethylene terephthalate glycol aligners showed significantly higher initial insertion forces than polyurethane aligners. After being immersed in artificial saliva for 24 hours, the aligners’ mean loss of efficiency was approximately 40%. Polyurethane aligners were more affected by various solutions (particularly hot coffee) compared with polyethylene terephthalate glycol aligners, which seemed to deliver more constant forces. The forces did not decrease in any of the studied cases. Conclusion: Aligner performance is conditioned by the initial insertion force and the working range. Consumption of beverages and nicotine during aligner treatment does not appear to reduce aligner efficiency. Keywords: aligners, beverages, orthodontic forces, thermoplastic materials

Hyperdivergent Class II malocclusion is one of the most challenging types of malocclusions to treat using fixed appliances because distalisation is not recommended, so the possible options are extraction treatment or careful vertical correction. Clear aligners can be a useful option for treating hyperdivergent Class II patients without the need for extraction because they offer efficient control of the undesired extrusion during distalisation as molar intrusion can be planned and performed to control vertical excess. In many cases, treatment of vertical Class II malocclusion should involve a combination of transverse, vertical and sagittal correction. The present case report illustrates the orthodontic treatment for a hyperdivergent Class II adult patient in which distalisation and transverse and vertical correction were simplified by means of micro-osteoperforations performed selectively, beginning in the posterior region before progressing to the lateral sectors and then the anterior teeth to stimulate the bone in specific areas according to the movement sequence, thus reducing the need for patient compliance in using elastics for anchorage. The digital setup (ClinCheck, Align Technology, San Jose, CA, USA) was designed to enable sequential distalisation, expansion and molar intrusion to occur simultaneously. Distalisation was combined with anterior extrusion following smile arc exposure, and the treatment was completed over a period of 12 months.The present alternative for the treatment of hyperdivergent Class II malocclusion, i.e., combining selective micro-osteoperforations in the posterior and anterior regions with clear aligners, appears to increase the predictability of molar vertical control when performed simultaneously to expansion and distalisation and to induce a counterclockwise rotation of the mandible. Arch development, molar distalisation and intrusion with consequent mandibular rotation can be achieved predictably in a way that respects the digital setup and that creates a proper Class I bilateral occlusion, thus reducing the need for patient compliance in using maxillomandibular elastics for anchorage since the anchorage is modulated by selective micro-osteoperforations and a consequent regional acceleratory phenomenon. Keywords: aligners, micro-osteoperforations, open bite

In interproximal reduction, to gain space in the maxilla and mandible, the use of mechanically oscillating systems, and in particular diamond-coated abrasive strips, such as Oscident Strips (Oscident, Bad Homburg vor der Höhe, Germany) or the Ortho-Strips system (Intensiv, Montagnola, Switzerland), has proven clinically successful. By modifying the working area of the oscillating diamond strips in the Ortho-Strips system and leaving a non-diamond grain–coated zone of 0.5 mm at the upper and lower margins, unwanted abrasion and cervical step formation can be prevented, thus significantly increasing safety when using this system. Keywords: enamel reduction, interproximal reduction, oscillating strips, stripping