Journal of Aligner Orthodontics, 03/2019

With the spread of intraoral scanners and three-dimensional (3D) printers in the orthodontic practice, it is possible to realise a complete digital workflow for the production of aligners in the laboratory. Both intraoral scanners and cast scanners provide highly accurate virtual models for diagnosis and further use as virtual working models with reduced horseshoe base. Using appropriate software, the teeth can be segmented after tooth repair of the STL file and tooth movements simulated. This defines treatment goals (visual treatment objective). After disassembly into individual steps (staging), the individual working models can be produced with a 3D printer. For this purpose, digital light processing (DLP) or fused filament fabrication (FFF) printers can be used. The latter have specific advantages and disadvantages, but are seen as an interesting alternative. Further technical aspects and printing materials in FFF printing are discussed in detail. Clinical case studies illustrate the technical explanations. These show that FFF printers are suitable for the production of working models for aligner technology. Keywords: 3D printing, aligner, CAD/CAM, fused filament fabrication, in-office workflow, intraoral scanning

Objective: To evaluate differences in pain and discomfort between patients treated with clear aligners and those treated with traditional fixed orthodontic appliances. Materials and methods: 20 adult nonextraction patients were included in the fixed orthodontic appliances group (8 males, mean age 19.4 ± 4.4 years) and 20 in the clear aligners group (9 males, mean age 23.8 ± 4.4 years). Firstly, patients were asked to record their level of pain, intolerability and fatigue sensations during the first appointment (T0). Subsequently, patients were provided with a written diary to measure every day for one week (T1) their level of pain, speech difficulties, discomfort while eating, soft tissue decubitus and ulceration, difficulty in home oral hygiene, encumbrance of the tongue position and analgesic drugs consumption. The same diary was provided again after the adjustment appointment (T2). The data collected at T0 were analysed by means of an independent sample t test. For the remaining data, a two-way ANOVA was conducted. Sidak multiple comparison test was performed to compare the two groups at each time point. The level of significance was set at P 0.05. Results: Patients in the fixed orthodontic appliances group reported significantly more pain and intolerability at T0 (P = 0.035). Discomfort while eating, soft tissue decubitus and ulceration and home oral hygiene were statistically significantly lower in the clear aligners group at T1 than at T2. Conclusions: Therapy with traditional fixed orthodontic appliance caused more discomfort to the patients, as compared to clear aligner therapy. Keywords: brackets, clear aligners, orthodontic appliances

The purpose was to assess the aesthetic perception of laypersons belonging to different age groups on interproximal wear in the maxillary and mandibular incisors as an adjunct to orthodontic treatment. Photographs of smiles were taken from patients exhibiting normal occlusion and then manipulated to simulate wear in the mesiodistal width of maxillary and mandibular incisors with 25 different images being generated. These images were shown to laypersons aged 15 to 19, 35 to 44, and 65 to 74 years old, so that they could assess smile aesthetics. The participants used a visual analogue scale to give scores to the images. Peer comparisons were performed using the Mann-Whitney test. Statistical analyses were performed with a 95% confidence level. The vast majority of the participants failed to notice differences between the images presented, with no distinction between sexes or age. The average score given to the different photographs ranged from 6.48 to 6.81. The individuals of the oldest age group (65 to 74 years old) gave higher scores than the individuals of the younger age groups. Thus, the interproximal wear in the maxillary and mandibular incisors as an adjunct to orthodontic treatment did not affect smile attractiveness. Keywords: aesthetic perception, interproximal wear, smile attractiveness, orthodontic treatment

This article describes single-retainer resin-bonded fixed dental prostheses as an excellent minimally invasive alternative to other tooth replacements, and how orthodontic pretreatment with aligners might help to utilise this treatment modality. Two cases are presented in which the required space for the singleretainer resin-bonded fixed dental prostheses was not present initially; but by using a corresponding aligner, pretreatment predictably could be created. Keywords: aligner pretreatment, resin-bonded fixed dental prostheses (RBFDPs), single tooth replacement

Class III malocclusion cases can be some of the most difficult cases to treat, especially in non-growing patients. Many patients prefer to avoid surgical treatment if possible, and are interested in more conservative treatment options if available. In this case report, a Class III malocclusion was treated using the Invisalign appliance in combination with auxiliary devices as well as micro-osteoperforation to facilitate first molar space closure. The challenges of this Class III case include skeletal mandibular unilateral prognathism, missing mandibular left first molar, chin deviation, as well as lateral functional shift. Detailed diagnosis including cone beam computed tomography and clinical examination, as well as alternative treatments, are discussed. The results showed improvement in the patient's profile and occlusion as well as closure of the space of the mandibular left first molar. Limitations and criticism of the treatment outcome are also discussed. Keywords: chin deviation, Class III skeletal, clear aligners, functional shift, malocclusion, micro-osteoperforation

In this and future issues of the JAO we will be asking our affiliated scientific societies a series of questions to enable readers to discover more about each group's work in the field of aligner orthodontics.