International Orthodontics最新文献

This case report describes a complex full-step class II case in a young adult patient treated with lingual straight-wire appliance and upper first molar extraction. As the patient refused a surgical treatment, she was offered the best possible camouflage with the double aim of obtaining an ideal occlusal relationship and maintaining the profile; appropriate biomechanical strategies, including extraction choice and anchorage control during space closure, were needed to achieve the planned results. This case report demonstrates the possibility of successfully resolving severe sagittal discrepancies in an adult patient without surgical treatment by means of a completely invisible non-compliance technique, with the extraction of the most compromised teeth. This report also underlines the need for careful planning during both diagnostic and treatment phases, in order to obtain the best results.

Background

Facial soft tissue analysis is becoming increasingly emphasized in orthodontic diagnosis and treatment planning. While traditional cephalometry primarily focuses on hard tissues, recent non-invasive imaging techniques offer the potential to comprehensively evaluate three-dimensional (3D) facial soft tissues. The aim of the study was to establish the geometrical 3D and cephalometric divergence between Cone Beam Computed Tomography (CBCT) derived images and scanned soft tissues. Crucial for enhancing orthodontic diagnosis, minimizing patient exposure to ionizing radiation and providing facial cephalometric parameters.

Material and methods

A cross-sectional study was conducted from January 2020 to May 2023. CBCT and 3D facial scans were obtained simultaneously using a specialized imaging system. Reproducible landmark points were selected for both cephalometric and soft tissue analysis. Angular and linear measurements were recorded, and correlations between CT and facial scans were statistically assessed.

Results

Comparisons between 10 CBCT-derived and 10 facial scan-based soft tissue representations resulted into 1.8 mm mean root median square (RMS). Angular measurements, such as ANB, right gonial angle, and left gonial angle, exhibited a 0.9° of difference with their respective soft tissue variables. In contrast, linear measurements of total anterior facial height showed a lower correlation coefficient, equal to 0.51. The correlation between soft tissues and underlying hard tissues was more pronounced for gonial angles.

Conclusion

Facial soft tissue analysis using either 3D facial scans or CBCT-derived offers similar results for orthodontic diagnosis and treatment planning. These findings support the use of non-invasive diagnostic tools in orthodontics, although further investigations are needed to comprehensively understand the complexity of hard and soft tissue relationships.

Objective

This study aimed to evaluate how the addition of resveratrol nanoparticles (RNPs), which act as an antimicrobial agent, affects the strength of acrylic resin used in orthodontics.

Methods

According to ISO 20795-1-2013, 76 cold cure acrylic resin samples (65 × 10 × 3.3 mm) were prepared. The samples were divided into four groups (19 samples in each group) based on RN concentrations added to 1 mL acrylic monomer (0 for control, 256, 512, and 1024 μg/mL). Flexural strength was assessed in megapascal (MPa) using a universal testing machine. Data analysis involved nonparametric Kruskal-Wallis analysis of variance and pairwise post-hoc Dunn's test.

Results

The flexural strength decreased as the concentration of RNPs increased, with the lowest value observed at 1024 μg/mL (63.06 ± 5.33 MPa). The control group exhibited the highest mean of flexural strength (88.43 ± 4.41 MPa), followed by the groups with RNPs at the concentrations of 256 μg/mL (82.69 ± 4.41 MPa) and 512 μg/mL (76.02 ± 4.59 MPa).

Conclusion

In conclusion, the addition of RNs to orthodontic acrylic resin had a dose-dependent impact on its flexural strength. Based on the findings, we recommend incorporating RNs at a concentration of 256 μg/mL as an antimicrobial agent in orthodontic acrylic resin. However, further research is necessary to assess the long-term effects and clinical applications of this approach.

Non-surgical treatment of Class II subdivision may involve complex mechanics or asymmetric tooth extraction in its resolution. This report demonstrates the result and the short-term stability of Class II subdivision treated with asymmetrically installed Herbst appliance followed by conventional fixed orthodontic appliance. The approach allowed the correction of the unilateral Class II molar relationship and increased overjet, as well as the deviation of dental midlines, with improvement in lip posture and facial profile. The results remained stable two years after treatment, confirming the treatment success.

Introduction

Detailed insight regarding the use of temporary anchorage devices (TAD) in Australia and the United Kingdom (UK) is lacking. The primary aim of the present cross-sectional survey was to investigate TAD usage among UK-based and Australian-based orthodontists. The secondary objectives were to compare TAD-related preferences and protocols between orthodontists in the two countries.

Methods

A pilot-tested electronic questionnaire was distributed to members of the British Orthodontic Society and the Australian Society of Orthodontists. Questions pertained to their demographic details, and current use of TADs including protocols, treatment objectives and factors influencing their use.

Results

A total of 192 responses were recorded (Australia: 122; UK: 70). One hundred and forty-two respondents (74.0%) reported using TADs as part of their orthodontic treatment, 77.0% in Australia (n = 94) and 68.6% in the UK (n = 48). Molar protraction was the most common procedure for which TADs were reportedly used (Australia: n = 118; 87.2%, UK: n = 36; 75.0%). “Loosening” was the most prevalent reported complication overall (n = 124; 90.1%). “Confidence”, “insufficient postgraduate education” and “availability of equipment” were the factors that most influenced the decision not to provide TADs.

Conclusions

Most orthodontists in both countries provided TADs. TAD protocols of orthodontists in both countries were reported. Similarities and differences regarding TAD-related clinical practices and procedures, complications and factors influencing the use of TADs and reasons for not using TADs were explored. Information from the present study can provide baseline data for future related studies in each country and for comparison of TAD usage in other countries.

Date of birth

24/09/1998; sex: female.

Pre-treatment documents

13 years 5 months old; 07/03/2012.

Diagnosis

Skeletal Class I with biretrusion, hypodivergent facial pattern; angle's Class II division 1 with overbite; moderate dento-maxillary discrepancy; maxillary incisor malposition.

Treatment planning

Bimaxillary buccal fixed appliance with Class II elastics. Active treatment duration: 25 months.

Post-treatment documents

15 years 7 months old; 09/05/2014.

Post-retention documents

(minimum 1 year) 16 years 9 months old; 08/07/2015. Retention period: unlimited.

Introduction

This study aimed to discover the genetic and environmental factors that contribute to the mandibular development of untreated monozygotic and dizygotic twins.

Material and methods

The sample, taken from the Forsyth Moorrees Twin Study, included 52 untreated monozygotic twins (36 male, 16 female) and 46 untreated dizygotic twins (23 male, 23 female). At the ages of 12 and 17, lateral cephalograms were collected and traced to assess total mandibular length, mandibular ramus length, mandibular corpus length, gonial angle, SNB, and bony chin prominence. The genetic and environmental components of variation were assessed using multilevel mixed-effects structural equation modelling.

Results

At 12 years of age, high additive genetic influences were observed for total mandibular length (74%), gonial angle (76%), SNB (41%), and bony chin prominence (64%), whereas strong dominant genetic components were observed for corpus length (72%), and mandibular ramus length was under unique environment influence (54%). At 17 years of age, only total mandibular length (45%), ramus length (53%), gonial angle (76%), and bony chin prominence (68%) were under strong additive genetic control, while the remainder were under strong dominant genetic control.

Conclusions

Although monozygotic and dizygotic twins share at least a portion of their DNA, additive, dominant, or environmental components were discovered during adolescence. Nonetheless, by the age of 17, the majority of the mandibular traits are under either additive or dominant genetic impact.