Effect of Treatment with Twin-Block Appliances on Body Posture in Class II Malocclusion Subjects: A Prospective Clinical Study

Cervical spine changes with functional appliance treatment: A systematic review and meta-analysis

Objective

Cervical spine posture is related to craniofacial morphology, airway, gait and body posture. This posture may be influenced by the changes in the mandibular position brought about by functional appliance therapy. Therefore, this systematic review aimed to assess the changes in the cervical spine posture with functional appliance treatment in Skeletal Class II subjects.

Methods

A search of studies in six electronic databases - Medline (via Pubmed), the Cochrane Library, OVID, LILACS, Scopus and Web of Science were performed until January 18, 2024 without any restriction in date or language of publication. Eligibility screening, study selection, and data extraction were performed by two reviewers independently. The risk of bias assessment of the included studies was performed with the Newcastle Ottawa scale and Cochrane RoB 2.0. Meta-analysis was performed using random effects model for assessment of changes in the cervical spine with removable and fixed functional appliances.

Results

Twelve articles that satisfied the eligibility criteria were included for systematic review and nine articles for meta-analysis. Five studies showed a low risk of bias, one as moderate and six as high risk of bias. GRADE assessment revealed a low quality evidence. Meta-analysis revealed a decrease of the upper cervical inclination by 1.16° (95 % CI of -2.68 to 0.35, I2 = 6 %), an increase of the middle cervical inclination by 2.20° (95 % CI of 0.46-3.94, I2 = 49 %), an increase in cervical curvature angle by 1.60° (95 % CI of 0.12-3.09, I2 = 89 %) and a decrease in cervical lordosis angle by 1.54° (95 % CI of -4.16 to 1.08, I2 = 0 %).

Conclusions

Minimal uprighting of the cervical spine was noted with functional appliances. Fixed functional appliances exerted a greater effect than removable functional appliances. Cervical hyperlordosis was reduced with removable functional appliance treatment. Though these changes are minimal, the clinical orthodontist should be aware that functional therapy also influences cervical spine posture. Due to the heterogeneity and low quality of evidence, the results are to be considered critically.

Comparison of Twin Block appliance and Herbst appliance in the treatment of Class II malocclusion among children: a meta-analysis

BACKGROUND

Our meta-analysis aimed to evaluate the efficacy of applying Herbst and Twin Block appliances in the treatment of Class II malocclusion among children.

METHODS

Databases, including PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI), China VIP Database (VIP), and Wanfang were thoroughly searched from inception to August 9, 2023. The outcomes included skeletal, dental, and soft tissue changes. The weighted mean difference (WMD) was used as the effect indicator, and the effect size was expressed with a 95% confidence interval (CI). The heterogeneity of each outcome effect size was tested, and the heterogeneity statistic I2 ≥ 50% was analyzed by the random-effect model, otherwise, the fixed-effect model was conducted. Sensitivity analysis was performed.

RESULTS

A total of 12 studies involving 574 patients were included in this meta-analysis. Herbst appliance had a statistically significant increase in mandibular body length (WMD: 1.44, 95% CI: 0.93 to 1.96, P < 0.001) compared with the Twin Block appliance. More increases in angle and distance of L1 to mandibular plane (MP) were found in the Herbst appliance compared with the Twin Block appliance. Significant and greater improvements in molar relationship (WMD: 0.79, 95% CI: 0.28 to 1.29, P = 0.002), posterior facial height (WMD: -1.23, 95% CI: -2.08 to -0.38, P = 0.005), convexity angle (WMD: -1.89, 95% CI: -3.12 to -0.66, P = 0.003), and Sella-Nasion plane angle (U1 to SN) (WMD: 3.34, 95% CI: 2.25 to 4.43, P < 0.001) were achieved in the Twin Block appliance. Herbst and Twin Block appliances produced similar effects in the skeletal and dentoalveolar changes including Sella-Nasion-point A (SNA), Sella-Nasion-point B, point A-Nasion-point B (ANB), overjet, and overbite.

CONCLUSION

As the findings revealed both Herbst and Twin Block appliances contributed successfully to the correction of Class II malocclusion. Compared with the Twin Block appliance, the Herbst appliance may have more advantages in mandibular bone movement. Twin Block therapy resulted in more improvement in the aesthetics of the face.

Evaluation and Comparison of Cervical Spine Posture in Class II Division I Patients Treated with Twin Block Appliances, Forsus Appliances, and Bilateral Sagittal Split Osteotomy: A Cephalometric Study

Background

It has been speculated that a change in cervical spine posture occurs due to forward repositioning of the mandible. Therefore, this study aimed to evaluate and compare the cervical spine posture in Class II division one patient treated with three different treatment modalities.

Materials and Methods

A retrospective cohort study was conducted using pre and post-treatment lateral cephalograms of Class II Division one patients who have undergone orthodontic therapy using twin block appliance, Forsus, and bilateral sagittal split osteotomy (BSSO). This study included a total of 57 subjects comprising 19 subjects in each group. Seven cervical, three sagittal, and one vertical parameters were compared within and between each group. The data were tested using the Dependent t-test, One-way analysis of variance, and Tukey's post hoc test.

Results

A significant difference existed between the pre- and post-treatment angular measurements within the three groups showing a change in the cervical spine posture with forward positioning of the mandible. A comparison of mean changes in angular measurements between the three groups showed a significant difference in SNA, SNB, ANB, and odontoid process tangent-cervical vertebral tangent (OPT-CVT), indicating a change in the cervical posture.

Conclusion

OPT-CVT angle predicts a change in cervical spine posture after treatment with a significant difference in the Twin Block group (P = 0.029) compared to Forsus and BSSO groups. Thus, the twin block group results in a more upright craniocervical posture than the other two treatment groups.

Relationship between Craniocervical Posture and Sagittal Position of the Mandible: A Systematic Review

Changes in craniocervical posture are a critical issue in modern society. Alterations of the mandible position in the anterior-posterior direction in association with head and neck posture are reported. The objective of the present review was to evaluate the relationship between craniocervical posture and sagittal position of the mandible and to evaluate the risk of bias inthe included studies. Electronic databases used to perform the search were PubMed, Wiley Online Library, and Cochrane. Only clinical trials that assessed sagittal craniocervical posture and mandible position in lateral cephalograms were included. Selected inclusion criteria were used to assess the finally selected studies. The upper and lower cervical spine was evaluated by seven and six studies, respectively. The risk of bias in the included studies varied from low to moderate. Literature research identified 438 records from 3 databases. Eventually, seven eligible clinical trials were included in this review. Evaluating the relationship between craniocervical posture and mandible position in the sagittal plane, it can be concluded that increased cervical inclination and head upright position are associated with the posterior position of the mandible. Attention to patients’ craniocervical posture should be paid as a part of clinical evaluation since it might be the reason for the changed mandible position.

Interaction between posture and maxillomandibular deformity: a systematic review

Maxillomandibular deformity (MMD) and body posture appear to be correlated. However, no systematic literature review of the available evidence to support this correlation has been performed to date. The aim of this study was to conduct a systematic literature review on posture and MMD. This systematic literature review was registered in the PROSPERO database. Systematic searches of the MEDLINE, Scopus, Cochrane Library, and Web of Science databases were performed. In total, 13 clinical studies were included. Nine found a significant association between MMD and body posture or body balance: two studies showed a correlation between increased cervical lordosis and skeletal class III MMD, two studies showed an interaction between mandibular deviation and scoliosis, four studies demonstrated a significant association between lumbar column and pelvis anatomy and MMD, and one study found a correlation between displacement of the centre of mass and MMD. However, the level of evidence is low; the methods used to evaluate body posture and MMD were inconsistent. Orthognathic surgery could modify body posture. Although there seems to be an interaction between body posture and facial deformity, the number of studies is too small and the level of evidence too low to strongly support this association.

Comparison of Dentoskeletal Changes, Esthetic, and Functional Efficacy of Conventional and Novel Esthetic Twin Block Appliances among Class II Growing Patients: A Pilot Study

Objective

A twin block appliance used for correction of skeletal Class II malocclusion suffers from undesirable dental effects and bulkiness. To overcome these limitations and the need for more esthetic appearance of this appliance, an esthetic twin block was designed and used in patients. This study aimed to compare dentoskeletal changes and esthetic and functional efficacy in patients treated with conventional and newly designed esthetic twin block (CTB and ETB) appliances using cephalometric measurements and a questionnaire.

Methods

A pilot study with a 2-arm parallel-randomized double-blind clinical trial was conducted on 24 patients (20 males, 4 females) in the age group of 11-13 years. Subjects were treated with CTB (group 1 [G1]: n=12; mean age=11.67±0.49 years) and ETB (group 2 [G2]: n=12; mean age=11.75±0.62 years) appliances. A modified Pancherz analysis was performed to evaluate skeletal and dental changes. The esthetic and functional efficacy was evaluated by a questionnaire using Likert scale. Wilcoxon and Mann-Whitney U tests were employed for intra and intergroup comparisons respectively (p<0.05).

Results

In G1, a significant increase in lower incisor inclination was observed (p<0.05) whereas it was insignificant in G2. The changes were predominantly skeletal in G2 whereas they were both skeletal and dental in G1. ETB was found to be esthetically and functionally acceptable in all the patients while CTB patients were esthetically conscious, lacked confidence and had discomfort and difficulty in eating, chewing and speaking.

Conclusion

ETB had greater skeletal effects with a reduced tendency of lower incisor proclination, was esthetically acceptable, and functionally more comfortable than the CTB.

The inconclusiveness of research on functional pathologies of the temporomandibular system and body posture: Paths followed, paths ahead: A critical review

Objective: Literature on the functional pathologies of the temporomandibular system (FPTS) in its relationships with body posture is plagued with inconclusiveness. Despite being sometimes altogether disregarded, the issue is most relevant, due to its clinical implications. This paper aims for a deeper understanding of the origins of the inconclusiveness of research on such relationships by means of a critical analysis of the scientific literature on the subject, in order that clinicians may better treat patients with FPTS.Methods: Analysis of over 100 studies, published from 1918 through March 2018 in the PubMed database, using descriptors temporomandibular joint disorders and posture.Results: The analysis of the paths followed by researchers allowed for pinning down several methodological issues that may have led to the prevailing ambiguity on the matter.Conclusion: This review then proposes certain standardization of procedures in future studies, to be conducted by a proposed consortium of researchers.

Relationship between foot posture and dental malocclusions in children aged 6 to 9 years: A cross-sectional study

The aim of this study was to determine the association, if any, between foot posture and dental malocclusions in the anteroposterior plane, in children.The study population consisted of 189 children (95 boys and 94 girls) aged 6 to 9 years. In every case, previous informed consent was requested and obtained from the parent/guardian and the study was approved by the Ethics Committee of the University of Málaga (CEUMA 26/2015H).This observational, descriptive, cross-sectional analysis is based on a study population (STROBE). Qualified personnel conducted a podiatric and dental examination of each child, recording the Clarke angle and the foot posture index (FPI) as an outcomes measure in the feet, and also dental malocclusions, according to Angle classification.A significant correlation was observed for the FPI scores (for right foot) as well as the Clarke angle (for right foot), in relation to dental malocclusions as determined by Angle classification (P < .001). Of all the supinated feet analyzed, 38.46% were Class II according to Angle classification, and none were Class III. Of the pronated feet, 48.57% were Class III, 42.85% were Class I, and 8.57% were Class II.The Clarke angle decreases with the progression from Class I to III, whereas the FPI increases with that from Class I to III. These findings suggest there is a relation between the Clarke angle and FPI, on the one hand, and dental malocclusion on the other.