Effectiveness of Functional Mandibular Advancer in Patients with Class II Malocclusion: A Systematic Review and Meta-analysis

Objective

We aimed to evaluate the effectiveness of functional mandibular advancer (FMA) in treating growing patients with Class II malocclusion.

Methods

Electronic searches were conducted in MEDLINE (via PubMed), Cochrane Library, Web of Science, Scopus, Embase, and Lilacs from 1945 to 30th November 2021. Studies were selected based on the following inclusion criteria: human studies, Class II growing patient treated with FMA, untreated control group or a comparable group treated with another fixed functional appliance, pre- and post-treatment lateral cephalograms/magnetic resonance imaging/cone-beam computed tomography, randomized clinical trials, prospective studies, and retrospective studies. Data extraction of the included articles was independently performed independently by two authors. The risk of bias was assessed using the ROBINS-I tool. Meta-analysis was performed using the inverse generic model.

Results

Seven articles met the criteria and were included in the systematic review and three articles were included in the meta-analysis. Three studies had at low risk of bias and four studies had a moderate risk of bias. All articles reported anterior positioning of the mandible along with an increase in mandibular length. The meta-analysis results indicated a negligible difference between FMA and other functional appliances for the parameters SNA [0.11, 95% confidence interval (CI) of -1.07 and 1.29] and ANB (-1.00, 95% CI of -1.34 and -0.65). The evidence was limited for soft tissue changes.

Conclusion

Class II correction with FMA involved a combination of skeletal and dentoalveolar changes and was similar to other fixed functional appliances.

Prevalence, etiology, clinical features and management associated with impacted and transmigrated mandibular canines: a systematic review

BACKGROUND

The occurrence of mandibular canine impaction and/ or transmigration is a rare clinical entity but diagnosis and treatment planning is of clinical significance. The associated etiological factors and the clinical guidelines for the management are still not clear. The aim of this systematic review was to summarize the available data to report the prevalence and identify the etiological factors, clinical features, and various treatment outcomes in patients with mandibular canine impaction and/or transmigration.

METHODS

The review protocol was registered in PROSPERO (CRD42021222566) and was conducted and reported according to the PRISMA and Cochrane Handbook / Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. A computerized search of studies published up to April 30, 2023, was conducted using the following databases: Medline, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Scopus, Web of Science, and Latin American and Caribbean Health Sciences Literature. A manual search of the reference and citation lists of eligible articles and existing systematic reviews for any additions were also conducted. The Newcastle-Ottawa Scale quality assessment tool was used to assess the studies' quality.

RESULTS

After removing 6 duplicates, 3700 articles were identified. For the final analysis, 19 studies published between 1985 and 2023 met all the eligibility criteria and were included. A total of 7 studies presented as good and 12 studies presented as satisfactory. Patients were screened in ten studies and diagnostic records from archives were retrieved in nine studies. The total number of diagnostic records screened was 138.394, and the total number of patients from the included studies was 43.127.

CONCLUSIONS

Based on the findings from this systematic review, the prevalence of mandibular canine impaction ranged from 0.008% to 1.29% while canine transmigration from 0.12% to 0.98%. Crowding of the mandibular arch, the presence of a retained deciduous canine, and odontoma or cyst are the etiological factors more commonly associated with mandibular canine impaction and or transmigration. Surgical extraction and surgical exposure followed by orthodontic traction are the two most frequently carried out treatment modalities in the management of mandibular canine impaction and or transmigration.

Antimicrobial efficacy of zinc oxide nanoparticle-coated aligners on Streptococcus mutans and Candidaalbicans

INTRODUCTION

This study aimed to assess the antimicrobial effect of zinc oxide (ZnO) nanocoating on aligners.

METHODS

Twenty-six samples of aligners were sputter-coated with ZnO nanoparticles and compared with 26 uncoated samples. The antimicrobial effect was assessed on Streptococcus mutans and Candida albicans. The thickness of the ZnO coating was standardized at 100 nm. The antimicrobial effect was evaluated for 7 days at the following time points: 6 hours, 12 hours, first day, second day, fourth day, and seventh day. Colony culture tests were performed for microbial evaluation.

RESULTS

ZnO-coated aligners showed significant antimicrobial efficacy against S mutans at all time points tested (P <0.001). The antimicrobial effect was observed up to 2 days after a decline. The activity against C albicans was minimal at all time points, and no statistical significance was observed (P >0.05).

CONCLUSIONS

ZnO-nanocoated aligners were effective against S mutans, with the maximum antibacterial effect observed until 2 days and lasting for 7 days. The effect against C albicans was minimal. ZnO-coated aligners appears to be a promising technique to facilitate antimicrobial efficacy against S mutans.

Prevalence of Body Dysmorphic Disorder among patients seeking orthodontic treatment

Background

Body Dysmorphic Disorder (BDD) is a psychiatric disorder with delusions about defects in appearance for which patients seek various treatments. Patients with BDD often seek cosmetic procedures, and orthodontic treatment is one among them. This is the first Indian study to determine the prevalence of BDD in an orthodontic outpatient department.

Materials and method

A total of 1184 patients with varying degrees of malocclusion completed the BDD-YBOCS questionnaire, while an experienced orthodontist assessed the severity of malocclusion with a rating scale.

Results

Sixty-two patients (5.2%) were screened positive for BDD. Most of the BDD-positive patients were single (p value of 0.02) and had multiple previous consultations for orthodontic treatment (p value of < 0.00**) with a gender predilection toward males (p value of 0.00**), and age was not statistically significant with a p value of 0.3.

Conclusion

From our study, the prevalence of BDD among orthodontic patients was 5.2%. The orthodontist should be aware of the high prevalence of BDD among orthodontic patients and identify the expectations of the patient at the time of history taking and refer the patient to a psychiatrist for diagnosis and appropriate management.

Effect of functional appliances on the airway dimensions in patients with skeletal class II malocclusion: A systematic review

OBJECTIVES

The aim of the present systematic review was to assess the effect of functional appliances on the airway dimensions in patients with skeletal Class II malocclusion.

MATERIALS AND METHODS

Articles were identified through a literature survey carried out through the following databases: (1) PUBMED, (2) Google Scholar, (3) The Cochrane Library, (4) Embase, (5) Lilac, and (6) Web of Scholars. The systematic review analyzed 12 articles comprising removable functional appliances, 3 articles with fixed functional appliances, and 2 articles having both fixed and removable functional appliances.

RESULTS

Qualitative assessment was done for all the 17 studies. The effect of functional appliances in the dimensions of three airway spaces - nasopharynx, oropharynx, and hypopharynx were analyzed.

CONCLUSIONS

Significant increase in the dimensions of nasopharynx and oropharynx was observed with Activator. Significant increase in the nasopharynx and hypopharynx (male patients) was observed with Bionator. Insignificant increase in the oropharynx was observed with the same. Significant increase in the oropharynx and hypopharynx was observed with Twin Block. Insignificant increase in the nasopharynx was observed with the same. Significant increase was observed only in the hypopharynx for Frankel II. Decreased or insignificant change was observed with FMA, MPA IV, and Herbst appliances.

Sella turcica-Its importance in orthodontics and craniofacial morphology

The sella turcica is a structure which can be readily seen on lateral cephalometric radiographs and sella point is routinely traced for various cephalometric analyses. The search was carried out using the following key words (sella turcica, bridging of sella, size, shape of sella turcica) and with the following search engine (Pubmed, Cochrane, Google scholar). The morphology is very important for the cephalometric position of the reference point sella, not only for evaluating craniofacial morphology, but also when growth changes and orthodontic treatment results are to be evaluated. This makes it a good source of additional diagnostic information related to pathology of the pituitary gland, or to various syndromes that affect the craniofacial region. Clinicians should be familiar with the normal radiographic anatomy and morphologic variability of this area, in order to recognize and investigate deviations that may reflect pathological situations, even before these become clinically apparent. During embryological development, the sella turcica area is the key point for the migration of the neural crest cells to the frontonasal and maxillary developmental fields. The neural crest cells are involved in the formation and development of sella turcica and teeth. The size of sella turcica ranges from 4 to 12 mm for the vertical and 5 to 16 mm for the anteroposterior dimension. There are many classification systems regarding the shape of sella turcica. Majority of the studies show that about 67% of the subjects had normal appearance and about 33% showed variations. The prevalence of sella turcica bridging is high in class III malocclusions and dental anomalies.

Assessment of maximum voluntary bite force in adults with normal occlusion and different types of malocclusions

AIM

Maximum voluntary bite force (MVBF) was assessed in adults with class I normal occlusion and compared with different malocclusions.

MATERIALS AND METHODS

One hundred and ten subjects in the age group of 17 to 25 years were classified into various groups. Thirty subjects with class I normal occlusion (Group A), 20 subjects with Angle's class I malocclusion (Group B), 20 subjects with skeletal class II malocclusion (Group C), 20 subjects with hypodivergent facial morphology (Group D) and 20 subjects with hyperdivergent facial morphology (Group E). MVBF was measured with a bite force meter at the first premolar and first molar region bilaterally. The values were recorded and statistically analyzed.

RESULTS

Mean MVBF value in each of the groups in the molar and first premolar region were found to be 601.83N ± 60.80, 392N ± 31.43 (group A), 592.60N ± 37.66, 378.90N ± 23.00 (group B), 586.60N ± 49.26, 377N ± 29.38 (group C), 771.50N ± 27.24, 500.60N ± 18.25 (group D), 283.85N ± 26.41, 283.85N ± 26.41 (group E). Student paired t-test was done to analyze the difference between two groups and considered as significant at a p-value of < 0.05. Significant difference was found between group A and D and group A and E with a p-value of <0.0001. No significant difference was observed between group A and group B (p = 0.5481 and 0.1148) and group A and group C (p = 0.3551 and 0.0949). ANOVA showed that there was a significant difference among groups A, D and E. No significant difference was found among groups A, B and C. Males had a higher value than females.

CONCLUSION

Sagittal morphology does not significantly affect the MVBF value whereas there is a significant correlation with vertical morphology.

CLINICAL SIGNIFICANCE

Assessment of maximum voluntary bite force (MVBF) is a chairside procedure to evaluate masticatory muscle activity based on which treatment planning and mechanics can be known.