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.

The Potential Use of Pharmacological Agents to Modulate Orthodontic Tooth Movement (OTM).

The biological processes that come into play during orthodontic tooth movement (OTM) have been shown to be influenced by a variety of pharmacological agents. The effects of such agents are of particular relevance to the clinician as the rate of tooth movement can be accelerated or reduced as a result. This review aims to provide an overview of recent insights into drug-mediated effects and the potential use of drugs to influence the rate of tooth movement during orthodontic treatment. The limitations of current experimental models and the need for well-designed clinical and pre-clinical studies are also discussed.

Are claims made in orthodontic journal advertisements evidence-supported?

OBJECTIVE: To examine the supporting evidence of advertisements published in six leading orthodontic journals. MATERIALS AND METHODS: The 2012-2013 printed issues of American Journal of Orthodontics and Dentofacial Orthopedics, Australian Orthodontic Journal, Journal of Orthodontics, European Journal of Orthodontics, Journal of Clinical Orthodontics, and Journal of Orofacial Orthopedics were screened for advertisements implying superior performance compared with competitor products. Advertisements were classified according to type of product, availability, and currency of supporting references. RESULTS: A total of 99 unique advertisements claiming clinical benefit or superiority were identified. The overwhelming majority of the identified advertisements promoted appliance products (62.6%), orthodontic materials (14.1%), and dental operatory equipment, including imaging systems (12.1%). Advertisements were found to provide references or not regardless of the product type. Half of the advertisements referred to at least one peer-reviewed publication, whereas unpublished studies were cited by 25% of the advertisements. Most of the referenced articles were published within the past 5 years. CONCLUSIONS: The scientific background of advertisements in the orthodontic literature appears limited. While surveillance of journal advertising needs to be regulated, clinicians are urged to critically appraise the claims being made in orthodontic print advertisements by consulting the associated existing evidence.

Effectiveness of non-conventional methods for accelerated orthodontic tooth movement: a systematic review and meta-analysis.

OBJECTIVES: To assess the available evidence on the effectiveness of accelerated orthodontic tooth movement through surgical and non-surgical approaches in orthodontic patients. METHODS: Randomized controlled trials and controlled clinical trials were identified through electronic and hand searches (last update: March 2014). Orthognathic surgery, distraction osteogenesis, and pharmacological approaches were excluded. Risk of bias was assessed using the Cochrane risk of bias tool. RESULTS: Eighteen trials involving 354 participants were included for qualitative and quantitative synthesis. Eight trials reported on low-intensity laser, one on photobiomodulation, one on pulsed electromagnetic fields, seven on corticotomy, and one on interseptal bone reduction. Two studies on corticotomy and two on low-intensity laser, which had low or unclear risk of bias, were mathematically combined using the random effects model. Higher canine retraction rate was evident with corticotomy during the first month of therapy (WMD=0.73; 95% CI: 0.28, 1.19, p<0.01) and with low-intensity laser (WMD=0.42mm/month; 95% CI: 0.26, 0.57, p<0.001) in a period longer than 3 months. The quality of evidence supporting the interventions is moderate for laser therapy and low for corticotomy intervention. CONCLUSIONS: There is some evidence that low laser therapy and corticotomy are effective, whereas the evidence is weak for interseptal bone reduction and very weak for photobiomodulation and pulsed electromagnetic fields. Overall, the results should be interpreted with caution given the small number, quality, and heterogeneity of the included studies. Further research is required in this field with additional attention to application protocols, adverse effects, and cost-benefit analysis. CLINICAL SIGNIFICANCE: From the qualitative and quantitative synthesis of the studies, it could be concluded that there is some evidence that low laser therapy and corticotomy are associated with accelerated orthodontic tooth movement, while further investigation is required before routine application.

The etiology of cleft palate formation in BMP7-deficient mice.

Palatogenesis is a complex process implying growth, elevation and fusion of the two lateral palatal shelves during embryogenesis. This process is tightly controlled by genetic and mechanistic cues that also coordinate the growth of other orofacial structures. Failure at any of these steps can result in cleft palate, which is a frequent craniofacial malformation in humans. To understand the etiology of cleft palate linked to the BMP signaling pathway, we studied palatogenesis in Bmp7-deficient mouse embryos. Bmp7 expression was found in several orofacial structures including the edges of the palatal shelves prior and during their fusion. Bmp7 deletion resulted in a general alteration of oral cavity morphology, unpaired palatal shelf elevation, delayed shelf approximation, and subsequent lack of fusion. Cell proliferation and expression of specific genes involved in palatogenesis were not altered in Bmp7-deficient embryos. Conditional ablation of Bmp7 with Keratin14-Cre or Wnt1-Cre revealed that neither epithelial nor neural crest-specific loss of Bmp7 alone could recapitulate the cleft palate phenotype. Palatal shelves from mutant embryos were able to fuse when cultured in vitro as isolated shelves in proximity, but not when cultured as whole upper jaw explants. Thus, deformations in the oral cavity of Bmp7-deficient embryos such as the shorter and wider mandible were not solely responsible for cleft palate formation. These findings indicate a requirement for Bmp7 for the coordination of both developmental and mechanistic aspects of palatogenesis.

The genetic basis of craniofacial and dental abnormalities.

The embryonic head development, including the formation of dental structures, is a complex and delicate process guided by specific genetic programs. Genetic changes and environmental factors can disturb the execution of these programs and result in abnormalities in orofacial and dental structures. Orofacial clefts and hypodontia/ oligodontia are examples of such abnormalities frequently seen in dental clinics. An insight into the mechanisms and genes involved in the formation of orofacial and dental structures has been gradually gained by genetic analysis of families and by the use of experimental vertebrate models such as the mouse and chick models. The development of novel clinical therapies for orofacial and dental pathological conditions depends very much on a detailed knowledge of the molecular and cellular processes that are involved in head formation.

N-terminal activation is an essential early step in the mechanism of action of the Bacillus thuringiensis Cry1Ac insecticidal toxin.

A variant form of the Bacillus thuringiensis Cry1Ac toxin that is not cleaved at the N terminus during proteolytic activation with trypsin was found to be incapable of forming pores in Manduca sexta brush border membrane vesicles in vitro and had reduced insecticidal activity in vivo. Binding studies indicated an altered binding pattern of the mutant toxin in that bound toxin could not be fully displaced by a high molar excess of fully trypsin-activated toxin. These results suggest that proteolytic removal of the N-terminal peptide of Cry1Ac is an important step in toxin activation.