Background: Orthodontic treatments have evolved significantly, with clear aligners becoming increasingly popular due to their aesthetic appeal and ease of use. This study systematically reviewed the impact of clear aligners in the changes in the oral microbiota compared to traditional fixed appliances. Methods: Following PRISMA guidelines, a systematic review was conducted using two databases such as Scopus, Web of Science, and the PubMed search engine. The studies included were those published between 2010 and 2023, involving adults over 18 years using clear aligners and fixed appliances. The data on oral microbiota changes were extracted and analyzed. Results: The review included eight studies, highlighting the differences in microbial changes associated with clear aligners versus fixed appliances. Clear aligners were associated with fewer detrimental changes in the oral microbiota, potentially due to their removable nature allowing for better hygiene. Fixed appliances showed a tendency to harbor more pathogenic bacteria, which is likely due to their difficulty to clean. Conclusions: Clear aligners may offer a better alternative to fixed appliances in terms of maintaining a healthier oral microbiota. Their design and ease of hygiene contribute to less accumulation of pathogenic bacteria, showing a more positive impact on maintaining a balanced oral microbiota when compared to fixed appliances.

The purpose of this study was to assess the accuracy and reliability of tooth width measurements and Bolton Indices delivered by the Clin-Check Pro 6.0 software (Align Technology, San José, CA, USA). Fifty-four plaster casts were selected and measured with a manual calliper by a trained and calibrated observer. The data gathered were compared with those delivered by the software on the corresponding fifty-four virtual casts. The method reliability of the software was assessed by comparing the measurements performed by the software on 201 pairs of clin-checks corresponding to two consecutive treatment phases. Accuracy and reliability were statistically assessed using a mixed model. The software tends to provide larger widths compared with the manual method. Statistically significant differences were found in 23 teeth. At a global level, the mean difference between the methods was −0.19 mm, with a Dahlberg error of 0.24 mm and an intraclass correlation coefficient of 0.98. The Bolton Indices delivered by the two methods had a moderate correlation (ICC = 0.59; 0.69). The within method reliability of the software was extremely high. Tooth width measurements delivered by the software, despite the positive bias, can be considered accurate and clinically acceptable for all teeth except molars. The Bolton Indices made available by the software are not accurate and clinically acceptable, especially in the case of mandibular excess.

Background: The precision of bracket manufacturing is fundamental to ensure the correct expression of the inbuilt information. The objective of this study was to determine the actual tip and torque values of a pool of stainless steel brackets, pre-adjusted according to the MBT prescription values, and to compare these actual values with those stated by the manufacturers in order to test their compliance with the tolerance limits reported in the ISO 27020:2019. Methods: A sample of 360 stainless steel brackets, from 12 different providers, were evaluated. All brackets had a nominal slot size of 0.022 in., belonged to the upper right central incisor, and were manufactured with the metal injection molding technique (MIM). For each provider, three different batches of the same bracket series were tested. A single-blind design was used for bracket coding. Results: Only five systems displayed torque mean values that matched the declared values (p > 0.05). Only one system did not respect the tolerance limits established in the ISO 27020:2019 norm. The tip values were different from those declared in seven of the assessed systems; however, none exceeded the tolerance limits. The inter-batch variability in most cases was not statistically significant. Conclusions: In most of the assessed systems, there can be a difference between the actual and the declared torque values, while tip information is usually accurately incorporated into the bracket slot. Lack of precision in the manufacturing process can reduce the efficacy of the appliance and force the clinician to compensate for dimensional inaccuracy through wire bending.