Journal of Aligner Orthodontics, 01/2018

Objectives: The objective of this study was to analyse the changes produced in each of the five variables of the Peer Assessment Rating (PAR) index in patients treated with the Invisalign System. Methods: In total, 77 patients (23 males and 54 females) with a mean age of 37.7 years (standard deviation 12.7), attending a private office and treated with the Invisalign System were selected. The same operator treated all patients. Initial and final virtual models obtained by the intraoral scanner iTero were selected. Using the Ortocad programme, the five parameters of the PAR index were measured in the virtual models: maxillary/mandibular anterior segments alignment, posterior occlusion, overjet, overbite, and discrepancy of the centre line. The degree of improvement was calculated from the differences between the initial and final PAR values. Results: Measurement reproducibility results showed an intra- observer coefficient of variation lower than the inter-observer coefficient (1.2% and 2.1%, respectively). The intra-class coefficient was 0.98 for intra-observer measurements and 0.91 for inter-observer measurements. 44.2% of the sample varied their PAR index in less than 10 points, 36.4% between 11 and 20 points, 14.3% between 21 and 30 points, and 5.2% decreased by almost 40 points in the PAR index. The total mean variation of the initial and final PAR index in patients treated with the Invisalign System was 13 points, an improvement of 57%. Conclusion: The variables of the PAR index with the greatest improvement after Invisalign System treatment were maxillary/ mandibular anterior segments alignment, overjet, overbite, and discrepancy in the centre line. Keywords: Invisalign, PAR, Peer Assessment Rating index

Objective: The aim was to conduct a semi-objective analysis of phonetic alterations in patients during the first 24 h after being fitted with F22 aligners. Our secondary objective was to analyse the patients' perception of any speech impediments caused by the aligners, and the impact of such alterations on their daily lives. Methods: Thirty patients were given the Fanzago articulation test at three different time points defined as T0 (before aligner fitting), T1 (immediately after aligner fitting) and T2 (24 h after aligner fitting), and results were evaluated independently by three speech therapists. Patients were also asked to fill in a questionnaire consisting of six items on their perception of any phonetic alterations provoked by the aligners, and the influence of this on their daily lives. Results: The results of the semi-objective analysis based on the Fanzago articulation test revealed the alteration of only three phonemes of the 28 assessed, specifically "s", "ts" and "ʃ". Furthermore, these alterations were only found in four out of 30 patients at T1, and three out of 30 patients at T2. The questionnaire revealed that 28 out of 30 patients perceived some speech anomalies, but that this had no significant impact on their daily lives. Conclusions: These findings show that F22-aligner therapy has no significant impact on patients' phonetic articulation; the alterations detected were slight and involved only three phonemes, "s", "ts" and "ʃ". Keywords: F22 aligner, orthodontic aligners, phonetic alterations

Objective: To establish a better understanding of the role of composite attachments in resultant displacement patterns during aligner-based rotational tooth movement. Methods: Computer assisted design (CAD) geometry of the upper right canine, the periodontal ligament (PDL), composite attachment and plastic aligner segment were digitally modelled and subsequently imported to ANSYS 16.1 finite element analysis (FEA) software. A 3-degree mesio-lingual rotation was imposed on the aligner segment, simulating aligner-based mechanics and clinical performance, with and without attachments. Results were compared to establish the role of composite attachments during aligner-based tooth rotation. Results: Intrusive displacement of canines was observed during aligner-based tooth rotation without attachment. The intrusive force was 2.5× greater when attachments were not included in simulation. A distinct "lag" was observed between aligner and tooth rotations, which reduced from 25% to 5% when attachments were added to the FEA simulation. Concentrated contact pressure areas were observed on the mesial and distal slopes of the incisal ridge. Conclusion: During aligner-based canine rotation, in the absence of attachments, intrusive forces as well as a "lag" between aligner rotation and the resultant movement of the tooth were observed. When specialised composite attachments were utilised, intrusive tendency and aligner-tooth rotational "lag" were significantly reduced, improving clinical predictability of aligner-based orthodontic systems. Keywords: aligner orthodontics, biomechanics, plastic aligners, rotation

In patients with premature loss of baby teeth and insufficient retention of spaces, the Leeway space can be reduced due to undesired neighbouring tooth migration and space could become insufficient for the eruption of all permanent teeth. Various orthodontic treatment options may be used to reopen spaces and avoid potential extractions in the permanent dentition. One option is treatment with the Invisalign Teen System, which allows an almost invisible and comfortable way of treating patients, with fewer potential side effects than with conventional fixed appliances. Several examples will be presented in this article to show how Invisalign treatment procedures in early years can avoid potential extraction treatments. Keywords: aligner orthodontics, case reports, ClinCheck Software, extractions, interceptive treatment, Invisalign, lack of space, mixed dentition, teen treatment