Are there differences in treatment effects between labial and lingual fixed orthodontic appliances? A systematic review and meta-analysis

Lever arm on bracket vs. lever arm on archwire: A 3D finite element method study of mechanics of miniscrew-supported lingual en-masse retraction of maxillary anterior teeth

OBJECTIVE

To compare the deformation of the main archwire and 3D movements of maxillary anterior teeth during miniscrew-supported en-masse retraction with the lever arm on the archwire and on the brackets in lingual orthodontic treatment in finite element analysis (FEM) simulation.

MATERIAL AND METHODS

A 3D dental-alveolar model with bonded 0.018×0.025-inch slot lingual brackets and a 0.017×0.025-inch dimension stainless-steel archwire was created. Four FEM models were created based on a 3D dental-alveolar model: in Models A and C, the lever arms were attached to the lingual bracket, while in Models B and D, the lever arms were attached to the archwire. Meanwhile, in Models A and B, the miniscrews were placed in between the molars, while in Models C and D, the miniscrews were positioned on the palatal roof. After a 1.5N retraction force was applied from the miniscrew to the end of the lever arm, the initial movements in the sagittal, transversal, and vertical planes were recorded and analysed for maxillary anterior teeth.

RESULTS

In Models B and D, smaller deformation of the main archwire and less prominent bowing effect were noticed in both sagittal and vertical directions compared to their counter groups. In Models C and D, the central incisors showed less torque loss in the sagittal direction and more canine intrusion vertically.

CONCLUSIONS

For the same lever arm-miniscrew retraction configuration, the lever arm on the bracket showed less deformation of the main archwire and more body movement of the teeth than the lever arm on the archwire group. With the same level arm height, the transverse and vertical bowing effect is reduced when the lever arm was placed distal to the central incisor and the miniscrews placed next to the palatal suture.

ACTIVATION OF FIXED LABIAL APPLIANCES, BRIEFLY AT INITIATION, MAY REDUCE MASTICATORY PERFORMANCE AND BITE FORCE

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

Duarte L, Bezerra AP, Flores-Mir C, De Luca Canto G, Pereira LJ, Vega Gonçalves TMS. Activation and installation of orthodontic appliances temporarily impairs mastication. Angle Orthod. 2022 Mar 1;92(2):275-286. doi: 10.2319/061,221-469.1. PMID: 34,878,525; PMCID: PMC8887415.

SOURCE OF FUNDING

Not reported.

TYPE OF STUDY/DESIGN

Systematic review with meta-analysis of data.

Antifungal therapy in the management of fungal secondary infections in COVID-19 patients: A systematic review and meta-analysis

Objectives

The prevalence of fungal secondary infections among COVID-19 patients and efficacy of antifungal therapy used in such patients is still unknown. Hence, we conducted this study to find the prevalence of fungal secondary infections among COVID-19 patients and patient outcomes in terms of recovery or all-cause mortality following antifungal therapy (AFT) in such patients.

Methods

We performed a comprehensive literature search in PubMed^®, Scopus^®, Web of Sciences^™, The Cochrane Library, ClinicalTrial.gov, MedRxiv.org, bioRxiv.org, and Google scholar to identify the literature that used antifungal therapy for the management fungal secondary infections in COVID-19 patients. We included case reports, case series, prospective & retrospective studies, and clinical trials. Mantel Haenszel random-effect model was used for estimating pooled risk ratio for required outcomes.

Results

A total of 33 case reports, 3 case series, and 21 cohort studies were selected for final data extraction and analysis. The prevalence of fungal secondary infections among COVID-19 patients was 28.2%. Azoles were the most commonly (65.1%) prescribed AFT. Study shows that high survival frequency among patients using AFT, received combination AFT and AFT used for >28 days. The meta-analysis showed, no significant difference in all-cause mortality between patients who received AFT and without AFT (p = 0.17), between types of AFT (p = 0.85) and the duration of AFT (p = 0.67).

Conclusion

The prevalence of fungal secondary infections among COVID-19 patients was 28.2%. The survival frequency was high among patients who used AFT for fungal secondary infections, received combination AFT and AFT used for >28 days. However, meta-analysis results found that all-cause mortality in COVID-19 patients with fungal secondary infections is not significantly associated with type and duration of AFT, mostly due to presence of confounding factors such as small number of events, delay in diagnosis of fungal secondary infections, presence of other co-infections and multiple comorbidities.

Effects of Skeletally Supported Anterior en Masse Retraction with Varied Lever Arm Lengths and Locations in Lingual Orthodontic Treatment: A 3D Finite Element Study

Objective

This study is aimed at analyzing different points of force application during miniscrew supported en masse retraction of the anterior maxillary teeth to identify the best line of action of force in lingual orthodontic treatment.

Materials and Methods

Three-dimensional (3D) finite element models were created to stimulate en masse retraction with different heights and positions of the miniscrew and lever arm to change the force application points; a 150 g retraction force was applied from the miniscrew to the lever arms, and the initial tooth displacements were analyzed.

Results

Lingual crown tipping and occlusal crown extrusion were seen at all heights and positions of the miniscrew and lever arm, but when the miniscrew height was at 8 mm and the power arm was located between the lateral incisors and canines, these tipping patterns were less than those obtained with a 4.5 mm high miniscrew and a lever arm located distal to the canines.

Conclusion

All miniscrew heights and lever arm positions showed initial lingual crown tipping and labial root tipping with occlusal crown extrusion. However, the 8 mm miniscrew height and the lever arm located between the lateral incisor and canine showed fewer amounts of these tipping patterns than a 4.5 mm miniscrew height and lever arm located distal to the canines. Therefore, this could be the preferred point of force application during en masse retraction in lingual treatment with additional torque control methods.

Assessment of salivary pro inflammatory cytokines profile level in patients treated with labial and lingual fixed orthodontic appliances

The secretions of certain cytokines, chemokines and growth factors are triggered by orthodontic appliances, which often affect the remodelling of periodontal tissues. Critical cumulative forces are applied by various types of orthodontic appliances to the periodontium. The secretion of such molecules is probably responsible, through molecular and cellular communications, for the optimal resorption of hard tissues in the periodontal setting, which therefore enables the coordination of multiple movements of tooth. This study assessed and compared a wide range of cytokines, cellular marker analysis and defensins present in the saliva samples of human subjected to orthodontic treatment with two different treatment modalities, i.e., conventional lingual and labial fixed orthodontic appliances. A total 40 samples of saliva were obtained, of which 20 were treated with traditional lingual appliances and 20 were treated with labial fixed appliances. After 21 days of treatment, all salivary samples were collected from the subjects. In order to analyse a broad range of soluble cytokine levels in saliva by flow cytometry, a bead-based immunoassay was performed. Cell surface markers were analysed by flow cytometry. Protein levels of saliva for defensins were quantified by ELISA. Non-significant differences were observed in the cytokine levels in the saliva except for the significant effects for CCL2, IL-17A and IL-6. Cellular markers CD45 and CD326 showed high percentage in conventional lingual samples. Defensin levels were found to be lower in conventional lingual patients. Subjects with conventional lingual appliances had significantly higher salivary protein levels of IL-1β, CCL2, IL17A, and IL-6, higher CD45+ and CD326+ cells and lower defensin levels than subjects with fixed labial appliances. The current study provided a clear basis for the development of innovative methods to aid in the improvement of various procedural treatments and orthodontic equipment of next generation.

Comparation of three methods for measuring the Edge Bevel Radius of rectangular orthodontic wires: An in-vitro study

OBJECTIVE

To establish a simplified method for measuring the edge bevel radius of 0.019×0.025-in steel rectangular orthodontic wires, achievable in the clinical environment, and to compare it with the photographic method.

MATERIALS AND METHODS

Aided by the AutoCAD™ 2016 software, the theoretical mathematical relationship was determined between the edge rounding radius and cross-sectional dimensions (height, width, diagonals), through rectangle drawings that represent cross-sections. Two hundred segments (n=20) were obtained from the posterior portions of 100 archwires from 10 brands (Dentaurum™; American-Orthodontics™; GAC™; 3M-Unitek™; Abzil™; Morelli™; Orthometric™; Aditek™; A-Company™; Orthomundi™). The cross-sectional measures of each segment were obtained with a micrometer and a caliper, and the edge bevel radii of these segments were calculated with the use of a mathematical formula. For the "gold standard", the segments were included longitudinally in a phenolic resin cylinder, cross-sectioned, polished, and photographed in scanning electron microscope (SEM). The images were amplified 770× and the radii were measured with an acetate template. The micrometer and caliper measuring methods were subjected to Bland-Altman analysis and compared with the gold standard (SEM), considering ±10μm as the maximum acceptable difference between methods.

RESULTS

In the micrometre measurement, 95% of the differences from the standard were within the limits of agreement (-7.21 and 5.56μm). For the caliper method, 95% of the differences were between -5.46 and 19.83μm, which exceeded the fixed limit ±10μm.

CONCLUSION

The calculation method with micrometre measurements is equivalent to the photographic method, but there is no such equivalence for the caliper measurements.

Lingual orthodontics in an adult patient with upper premolar extraction: Case report

OBJECTIVE

To show with this case report that lingual orthodontics can be a solution in complex adult situation and with interdisciplinary approach.

MATERIALS AND METHODS

The patient presented a dental and skeletal high angle class II division 1 with a previous extraction of one mandibular incisor. The strategy of treatment was upper first premolar-extraction to obtain a correction of the incisal-class II relationship with a normal lip function, a class II molar relationship on the right side and a class I on the left side. A lingual appliance and miniscrews were used.

RESULTS

The lingual orthodontic treatment with miniscrews responded to the occlusal objectives with a good upper incisors torque and retraction control.

DISCUSSION

Limits and advantages of lingual orthodontics were discussed.

CONCLUSION

Lingual mechanics can provide good results from both an aesthetic and function point of view in adult complex extractions case. It ensures aesthetics during treatment, incisor control during retraction. Miniscrews were also useful to overcome the periodontal limits and enhance the anchorage.

Effectiveness of lingual versus labial fixed appliances in adults according to the Peer Assessment Rating index

INTRODUCTION

The purpose of this study was to compare the effectiveness of lingual treatment and labial fixed appliances in the treatment of adult orthodontic patients.

METHODS

We conducted a retrospective study of 72 patients. The Peer Assessment Rating (PAR) index was measured at the start (T0) and end (T1) of treatment. Significant differences between treatment means were determined by means of analysis of variancewith the Bonferroni correction or with the use of Fisher exact test.

RESULTS

The lingual group had a mean pretreatment age of 28.6 ± 6.7 years, and the labial group had a pretreatment age of 26.6 ± 9.5 years. This difference was statistically not significant. The mean pre- and posttreatment PAR scores in the labial group were 22.9 ± 6.2 and 2.1 ± 2.3, respectively, and the mean pre- and posttreatment PAR scores in the lingual group were 26.5 ± 8.3 and 2.3 ± 2.5. There were no significant differences between the treatment groups.

CONCLUSIONS

Lingual and labial appliances produced similar reductions in PAR scores. There was no difference in the posttreatment PAR scores between the lingual and labial treatment groups. Further studies involving larger sample sizes and longer follow-up periods are required to confirm the results obtained.