Effect of Class II functional treatment on facial attractiveness, as perceived by professionals and laypeople

Long-term profile attractiveness of patients with Class I and II malocclusion treated with and without extractions: A 35-year follow-up

INTRODUCTION

The objective of this study was to compare the profile attractiveness in subjects treated with and without extractions after the long-term 35-year follow-up, according to laypeople, dentists, and orthodontists.

METHODS

A total of 40 patients with Class I and II malocclusion were divided into 2 groups, according to the treatment protocol: extraction (E) group, extractions of 4 premolars (n = 24), with mean pretreatment (T1), posttreatment (T2), and long-term posttreatment (T3) ages of 13.13, 15.50 and 49.56 years, respectively. The mean treatment time (T2 - T1) was 2.37 years, and the long-term follow-up (T3 - T2) was 34.19. Nonextraction (NE) group (n = 16), with mean ages at T1, T2, and T3 of 13.21, 15.07, and 50.32 years, respectively. The mean (T2 - T1) was 1.86 years, and the (T3 - T2) was 35.25 years. Lateral cephalograms were used to perform profile facial silhouettes, and an online evaluation was performed by 72 laypeople, 63 dentists, and 65 orthodontists, rating the attractiveness from 1 (least attractive) to 10 (most attractive). The intragroup comparison was performed with the repeated measures analysis of variance and Tukey tests. Intergroup comparison was performed with t tests, 1-way analysis of variance, and Tukey tests.

RESULTS

The E group had a longer treatment time than that of the NE group. In the pretreatment, posttreatment, and long-term posttreatment stages, the E and NE groups showed similar profile attractiveness. Laypersons and dentists were more critical than orthodontists.

CONCLUSIONS

At long-term posttreatment follow-up, profile attractiveness was similar in patients treated with and without extractions.

Towards Genetic Dissection of Skeletal Class III Malocclusion: A Review of Genetic Variations Underlying the Phenotype in Humans and Future Directions

INTRODUCTION

Skeletal abnormalities and malocclusions have varied features that impact populations globally, impairing aesthetics and lowering life quality. The prevalence of the Skeletal Class III disease is the lowest among all angle malocclusions, with varied prevalence across nations. Environmental, genetic, and societal factors play a role in its numerous etiologies. In this study, we conducted a thorough search across the published data relating to quantitative trait loci (QTL) and the genes associated with Class III progression in humans, discussed these findings and their limitations, and proposed future directions and strategies for studying this phenotype.

METHODS

An inclusive search of published papers in the PubMed and Google Scholar search engines using the following terms: 1. Human skeletal Class III; 2. Genetics of Human skeletal Class III; 3. QTL mapping and gene associated with human skeletal Class III; 4. enriched skeletal Class-III-malocclusion-associated pathways.

RESULTS

Our search has found 53 genes linked with skeletal Class III malocclusion reported in humans, genes associated with epigenetics and phenomena, and the top 20 enriched pathways associated with skeletal Class III malocclusion.

CONCLUSIONS

The human investigations yielded some contentious conclusions. We conducted a genome-wide association study (GWAS), an epigenetics-wide association study (EWAS), RNA-seq analysis, integrating GWAS and expression quantitative trait loci (eQTL), micro- and small-RNA, and long non-coding RNA analysis in tissues connected to skeletal Class III malocclusion phenotype in tissues connected with the skeletal phenotype. Finally, we invite regional, national, and international orthodontists and surgeons to join this effort by contributing human samples with skeletal Class III malocclusion following the accepted Helsinki ethical protocol to challenge these phenomena jointly.

Mechanical Characterization and Structural Analysis of Latex-Containing and Latex-Free Intermaxillary Orthodontic Elastics

Class II malocclusion is one of the most common dental anomalies and the use of intermaxillary elastomers is the standard method in its treatment. However, orthodontic elastics cannot exert continuous force over a period of time due to force degradation. Our goal was to mechanically characterize the different types of elastomers during static and cyclic loads, based on uniform methodology and examine the morphological changes after loading. Ten types of latex-containing and four latex-free intermaxillary elastics were examined from six different manufacturers. To determine the mechanical characteristics of the elastomers, tensile tests, cyclical tensile fatigue tests and 24 h relaxation tests were performed, and the elastics were also subjected to scanning electron microscopy (SEM) and Raman spectroscopy. Regardless of the manufacturer, the latex-containing elastomers did not show significant differences in the percentage of elongation at break during the tensile test. Only one type of latex-containing elastomer did not tear during the 24 h cyclical fatigue test. Fatigue was confirmed by electron microscopy images, and the pulling force reduced significantly. During the force relaxation test, only one latex-free ligature was torn; the force degradation was between 7.8% and 20.3% for latex ligatures and between 29.6% and 40.1% for latex-free elastomers. The results showed that dynamic loading was more damaging to ligatures than static loading, latex-containing elastomers were more resistant than latex-free elastics, and which observation could have clinical consequences or a potential effect on patient outcome.

The effect of orthodontic treatment on facial attractiveness: a systematic review and meta-analysis

BACKGROUND

Facial and smile attractiveness are significant motivating factor for patients to seek orthodontic treatment. Although there is a general belief that orthodontic treatment improves facial appearance, this has yet not been systematically evaluated.

OBJECTIVE

The objective of this study was to assess the current evidence on the effect of orthodontic treatment on facial attractiveness.

SEARCH METHODS

Systematic and unrestricted search of nine databases were performed up to January 2022.

SELECTION CRITERIA

Studies evaluating facial attractiveness before and after orthodontic treatment.

DATA COLLECTION AND ANALYSIS

Extracted data included study design and setting, sample size and demographics, malocclusion type, treatment modality, and method for outcome assessment. Risk of bias was assessed with the ROBINS-I tool for non-randomized studies and with RoB-2 for randomized controlled trials (RCTs). Random-effects meta-analyses of mean differences and their 95% confidence intervals (CIs) were performed.

RESULTS

Twenty studies were included in data synthesis; three randomized controlled clinical trials and 17 non-randomized clinical studies of retrospective or prospective design. One of the RCTs was found to have low risk of bias, one presented some concerns and the third showed a high risk of bias. All non-randomized studies showed either unclear or high risk of bias. Data syntheses showed that orthodontic treatment improved facial attractiveness ratings by 9% when compared with untreated controls (MD: 9.05/95% CI: 4.71; 13.39). A combination of orthodontics and orthognathic surgery also showed a positive effect of 5.5% (MD: 5.51/95% CI: 1.55; 9.47) when compared with orthodontic treatment alone. There was no difference in effect between extraction and non-extraction treatments (MD: -0.89/ 95% CI: -8.72; 6.94) or between different types of Class II correctors (MD: 2.21/95% CI: -16.51; 20.93).

LIMITATIONS

With the exception of two RCTs, included studies were of unclear or low quality.

CONCLUSIONS

Orthodontic treatment has a clinically weak effect on facial attractiveness when compared to no treatment. The same is true when a combined orthodontic/surgical treatment is compared to orthodontics alone.

REGISTRATION

PROSPERO #: CRD42020169904.

Soft tissue profile changes during treatment of patients with Class II malocclusion

Introduction/Objective. The class II malocclusion results in disbalanced facial harmony, primarily noticeable in the profile and the lower facial third. Aside from skeletal evaluation, orthodontic diagnosis and treatment planning should include facial soft tissue analysis. The aim of the study was to identify the soft tissue profile outcomes of orthodontic treatment of Class II, division 1 malocclusion patients and to determine if these changes are related with the different treatment protocol. Methods. The first group was the non-extraction group (25 patients) treated first with the Herbst appliance, and the second group was four premolars extraction group (25 patients) treated with a multibracket appliance. The patients? cephalograms and pre- and post-treatment profile photographs were used. Results. The improvement in the non-extraction group was evident in the decrease of the nasomental angle, the angle representing the projection of the upper lip to the chin, as well as the upper lip angle. In the extraction group, the nasolabial angle showed a significant increase. Soft tissue variables showed significant differences between the groups: the total facial angle or facial convexity including the nose and the angle presenting the projection of the upper lip to chin. Conclusion. The patients treated without extractions showed a significant improvement of the convex profile and favorable soft tissue changes in the lower third of the face.

Genes and Pathways Associated with Skeletal Sagittal Malocclusions: A Systematic Review

Skeletal class II and III malocclusions are craniofacial disorders that negatively impact people’s quality of life worldwide. Unfortunately, the growth patterns of skeletal malocclusions and their clinical correction prognoses are difficult to predict largely due to lack of knowledge of their precise etiology. Inspired by the strong inheritance pattern of a specific type of skeletal malocclusion, previous genome-wide association studies (GWAS) were reanalyzed, resulting in the identification of 19 skeletal class II malocclusion-associated and 53 skeletal class III malocclusion-associated genes. Functional enrichment of these genes created a signal pathway atlas in which most of the genes were associated with bone and cartilage growth and development, as expected, while some were characterized by functions related to skeletal muscle maturation and construction. Interestingly, several genes and enriched pathways are involved in both skeletal class II and III malocclusions, indicating the key regulatory effects of these genes and pathways in craniofacial development. There is no doubt that further investigation is necessary to validate these recognized genes’ and pathways’ specific function(s) related to maxillary and mandibular development. In summary, this systematic review provides initial insight on developing novel gene-based treatment strategies for skeletal malocclusions and paves the path for precision medicine where dental care providers can make an accurate prediction of the craniofacial growth of an individual patient based on his/her genetic profile.