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Background: White spot lesions (WSLs) are common adverse effects in fixed orthodontic treatment. Remineralising agents are widely used to prevent WSLs formation and are the first-line treatment for existing WSLs. Previous systematic reviews have evaluated the effectiveness of remineralisation agents in the management of WSLs. However, their conclusions were contradictory. The objective of this study will be to compare the effectiveness and safety of current remineralising agents used in the management of WSLs in patients treated with fixed orthodontic appliances in any orthodontic setting., Methods: Literature searches will be conducted in several electronic databases (from inception onwards): MEDLINE (via Ovid), Scopus, Embase, the Web of Science, and the Cochrane Central Register of Controlled Trials (CENTRAL), among others. Grey literature will be identified through searching clinical trials registries. Randomised controlled trials that compared the effectiveness of different remineralisation agents in the prevention and treatment of WSLs will be included. Two researchers will independently screen all citations, full-text articles, and abstract data. The study risk bias will be appraised using an appropriate tool. The primary outcomes will be WSLs incidence and severity of WSLs. Secondary outcomes will be subjective measures of WSLs and adverse effects. The mean difference (MD) and relative risk (RR) with corresponding 95% confidence intervals (CI) will be chosen as effect measures for continuous and binary outcomes, respectively. If feasible, fixed and random-effects pairwise meta-analyses and frequentist network meta-analyses will be conducted where appropriate., Discussion: This network meta-analysis will compare the effectiveness of remineralising agents in the prevention and treatment of orthodontically induced WSLs. By integrating the evidence from direct and indirect comparisons and ranking all evaluated interventions, our findings have the potential to help clinicians make more accurate treatment decisions., Systematic Review Registration: PROSPERO CRD42019116852, registered on March 15, 2019.

In the process of orthodontic treatment, root parallelism is related to the relapse of extraction spaces, black triangles, and periodontal health. However, there are few studies on root parallelism in extraction cases with different types of appliances. The objective was to compare the root parallelism in extraction cases treated with clear aligners vs. those treated with fixed appliances by measuring the differences per extraction site and to access the root-movement control capacity of both orthodontic appliances. A retrospective study was conducted on cases in which the first premolars were extracted, treated by clear aligner appliance ("Invisalign" system, 28 patients) or fixed appliance (30 patients). The angulations of the tooth axis (canines, the second premolars, the first molars, and the second molars) were measured to analyze and compare the difference in root parallelism between the two orthodontic appliances. The percentage of root parallelism between the canine and second premolar in both groups had no significant difference. However, judging from the average angle difference value, the fixed appliance might have a greater range in root angulation adjustment than the aligner. In the angulation categories, the aligner mainly showed root apical divergence, while the fixed appliance mainly showed root apical convergence. The dental crown of the molars was mainly non-tipping in both groups, but it could be observed that the dental crown of the maxillary molars had a tendency toward mesial inclination. In conclusion, the same root parallelism and root inclination were obtained in tooth extraction cases whether treated by clear aligners or fixed appliances. This study provides clinicians with more information on the performance of clear aligners and fixed appliances. [ABSTRACT FROM AUTHOR]

An orthodontic traction technique with a miniscrew-anchored cantilever spring was used for the traction of a deeply impacted maxillary third molar to substitute its adjacent second molar with severe root resorption. A 30-year-old woman sought multidisciplinary treatment planning for a second molar with severe root resorption caused by a deeply impacted third molar. Panoramic radiographs and cone-beam computed tomographic images showed that the third molar was located on the apical and palatal side of the second molar and that the second molar had severe root resorption. The second molar was removed, and the impacted third molar was orthodontically tractioned occlusally with the aid of a miniscrew-anchored cantilever spring. After 12 months of orthodontic treatment, the maxillary left third molar was successfully tractioned occlusally and well aligned with adjacent teeth for the substitution of the second molar. The patient was satisfied with the treatment outcome. A palatal miniscrew-anchored cantilever spring is an effective and viable technique for the orthodontic traction of deeply impacted third molars to substitute second molars with severe root resorption. [ABSTRACT FROM AUTHOR]

To measure the palatal thickness of both hard and soft tissues and to determine safe regions for the placement of mini-implants. The influences of sex and age on palatal thickness were also examined. Cone-beam computed tomography images of 30 patients (12 males, 18 females), including 15 adults and 15 adolescents, were used in this study. The thicknesses of palatal hard tissue, soft tissue, and hard+soft tissues were measured at the coronal planes of first premolars, second premolars, first molars, and second molars (P1, P2, M1, and M2 planes, respectively). The hard tissue was thickest at the P1 plane, followed by at the P2, M1, and M2 planes, while the thickness of soft tissue was similar among the four planes. The trends in the changes of palatal thickness from midline to the lateral sides (V-pattern) were similar for the four planes. Palatal thickness was influenced by sex, age, and their interaction. Mapping of recommended and optimal sites for palatal mini-implants was accomplished. Sex and age factors could influence palatal thickness. Therefore, the findings might be helpful for clinicians in guiding them to choose the optimal sites for palatal mini-implants. [ABSTRACT FROM AUTHOR]

Objectives: This 6‐month prospective clinical study assessed the impacts of Invisalign appliances on the oral bacterial community and oral health of patients. Methods: Salivary samples were obtained from twenty‐five adult patients receiving Invisalign aligner treatment before the treatment (Group B) and at a 6‐month follow‐up (Group P). The bacterial composition of each sample was determined using Illumina MiSeq sequencing of the bacterial 16S rRNA. Intra‐ and intergroup biodiversity was analyzed. Clinical periodontal parameters and daily oral hygiene habits were recorded. Results: Reduction in plaque, increased daily brushing frequency, and decreased dessert intake were observed in Group P compared with that in Group B. A total of 1,853,952 valid reads were obtained from the 50 salivary samples, with 37,904 sequences per sample. No significant differences were detected in the intra‐ and intergroup biodiversity comparisons between the two groups. By clustering, 8,885 OTUs were identified and categorized into six major phyla: Firmicutes, Proteobacteria, Bacteroidetes, Fusobacteria, Actinobacteria, and Candidate_division_TM7_norank. At the genus level, compared with Group B, Group P demonstrated significantly increased Bacillus abundance and decreased Prevotella abundance. Conclusions: Our results suggested that the general biodiversity and salivary microbial community structure did not change significantly and that patients had increased beneficial oral hygiene habits and awareness during the first six months of Invisalign treatment. Hence, on the basis of this study, it appears that Invisalign aligner treatment did not induce deterioration of oral health nor significant biodiversity changes in oral bacterial communities, assuming that detailed oral hygiene instructions for both teeth and aligners were provided. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effect of occlusal plane control on the hyoid bone position and pharyngeal airway of hyperdivergent skeletal Class II patients during orthodontic treatment. Materials and Methods: Cephalograms of 47 hyperdivergent skeletal Class II subjects with occlusal plane control (OPC), and another 50 subjects without occlusal plane control (NOPC) were selected to compare the effects of the occlusal plane control procedure. Lateral cephalograms before treatment (T1), immediately after treatment (T2), and an average of 12 months after treatment (T3) were obtained, and 17 measurements were analyzed in each group and compared between groups. Results: With respect to the T2−T1 changes, the sagittal discrepancies in both groups were alleviated. In the OPC group, both the occlusal and mandibular plane angles decreased, accompanied by anterior and superior movement and counterclockwise rotation of the hyoid bone. The overall changes from T3 to T1 in each group exhibited trends similar to that induced by treatment. As for pharyngeal airway space alterations, no significant difference in OPC group was presented throughout treatment or retention periods. Conclusions: The customized occlusal plane control procedure was effective for hyperdivergent skeletal Class II patients: The occlusal plane rotated counterclockwise, followed by a counterclockwise rotation of the mandibular plane. The hyoid bone moved anteriorly and superiorly, accompanied by its counterclockwise rotation. However, this procedure did not induce significant alteration of the pharyngeal airway space. [ABSTRACT FROM AUTHOR]

This study was carried out to evaluate pain in rats by monitoring their facial expressions following experimental tooth movement. Male Sprague-Dawley rats were divided into the following five groups based on the magnitude of orthodontic force applied and administration of analgesics: control; 20 g; 40 g; 80 g; and morphine + 40 g. Closed-coil springs were used to mimic orthodontic forces. The facial expressions of each rat were videotaped, and the resulting rat grimace scale ( RGS) coding was employed for pain quantification. The RGS score increased on day 1 but showed no significant change thereafter in the control and 20-g groups. In the 40- and 80-g groups, the RGS scores increased on day 1, peaked on day 3, and started to decrease on day 5. At 14 d, the RGS scores were similar in control and 20-, 40-, and 80-g groups and did not return to baseline. The RGS scores in the morphine + 40-g group were significantly lower than those in the control group. Our results reveal that coding of facial expression is a valid method for evaluation of pain in rats following experimental tooth movement. Inactivated springs (no force) still cause discomfort and result in an increase in the RGS. The threshold force magnitude required to evoke orthodontic pain in rats is between 20 and 40 g. [ABSTRACT FROM AUTHOR]

Background: Cervical vertebral maturation (CVM) is widely used to evaluate growth potential in the field of orthodontics. This study is aimed to develop an artificial intelligence (AI) system to automatically determine the CVM status and evaluate the AI performance. Methods: A total of 1080 cephalometric radiographs, with the age of patients ranging from 6 to 22 years old, were included in the dataset (980 in training dataset and 100 in testing dataset). Two reference points and thirteen anatomical points were labelled and the cervical vertebral maturation staging (CS) was assessed by human examiners as gold standard. A convolutional neural network (CNN) model was built to train on 980 images and to test on 100 images. Statistical analysis was conducted to detect labelling differences between AI and human examiners, AI performance was also evaluated. Results: The mean labelling error between human examiners was 0.48 ± 0.12 mm. The mean labelling error between AI and human examiners was 0.36 ± 0.09 mm. In general, the agreement between AI results and the gold standard was good, with the intraclass correlation coefficient (ICC) value being up to 98%. Moreover, the accuracy of CVM staging was 71%. In terms of F1 score, CS6 stage (85%) ranked the highest accuracy. Conclusions: In this study, AI showed a good agreement with human examiners, being a useful and reliable tool in assessing the cervical vertebral maturation. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "The effectiveness of laceback ligatures during initial orthodontic alignment: a systematic review and meta-analysis," by P. S. Fleming et al, published in a 2012 issue.