International Orthodontics最新文献

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.

Objective

The main objective of this review was to evaluate the effects of orthodontic intrusion on patients with reduced periodontium. Additionally, this review aims to explore the potential for attachment gain and tissue regeneration in these patients and identify optimal therapeutic conditions to mitigate any negative effects of intrusion.

Methods

A systematic review was conducted according to the PRISMA 2020 statement. Duplicate electronic searches of the PubMed, Cochrane, EMC Premium, and Science Direct databases were performed by two independent reviewers. Data extraction and quality assessments, including risk of bias evaluation using the Cochrane and ROBINS-I tools were conducted.

Results

From an initial pool of 418 articles, 29 were selected after title and abstract screening for full-text review. Following thorough full-text reading, 15 studies were ultimately included in the analysis. The total number of patients included in the studies is 528, who underwent orthodontic intrusion on reduced periodontium. Studies indicated a decrease in periodontal pocket depth and an increase in clinical attachment with ortho-periodontal treatment. Alveolar bone level outcomes varied, showing both increases and losses. Authors generally observed improved papillary regeneration and reduced gingival recessions.

Conclusion

Clinical studies involving combined ortho-periodontal treatment showed that orthodontic intrusion on a reduced but healthy periodontium can be considered a beneficial treatment for the periodontium, provided that potential adverse effects are carefully monitored.

Objective

The aim of this study is to compare the accuracy of cone beam computed tomography (CBCT) for dental model scanning to the accuracy of model scanners.

Methods

Subjects from private practice were collected and scanned according to specific selection criteria. A total of 10 STL files were produced and used as reference files. They were printed with a three-dimensional (3D) printer and then scanned with CBCT and model scanner. For trueness evaluation, all models were scanned once with both equipments. Each file derived from each scan was compared with the corresponding reference model file. For the precision measurements, the physical model from the first master reference model file was scanned 10 times with each equipment and compared with the reference STL file. A reverse engineering software was used for all 3D best-fit comparisons.

Results

With regard to the measurement of trueness of each method, the calculated mean root mean square (RMS) value was 0.06 ± 0.01 mm for the CBCT, and 0.15 ± 0.02 mm for the model scanner. There was a significant difference between the two methods (P < 0.01). For the evaluation of precision of each scanner, the mean RMS value was 0.0056 ± 0.001 mm for the CBCT, and 0.153 ± 0.002 mm for model scanner. There was a significant difference between the two methods (P < 0.01).

Conclusions

Cone Beam Computed Tomography seems to be an accurate method for scanning dental models. CBCT performs better than model scanners to scan dental models in terms of trueness and precision.

This case report describes a 19-year-old man presented with a 5.7-mm deep overbite, Class II division 2 malocclusion with the right upper maxillary canine completely buccal ectopia, deviated midline in the upper arch, severe crowding and retroclination of the maxillary and mandibular incisors. The patient was treated with clear aligners to correct the Class II relationship and the deep overbite. A series of clear aligners were used to move bilateral maxillary molars distally with unilateral mini-screw anchorage. The final results showed that clear aligners with mini-screws could effectively achieve the required upper distal molar movement thanks to a reasonable design of the stages and anchorage. The treatment was completed in 19 months and the patient was satisfied with the treatment outcome in this context of mild to moderate Class II division 2 malocclusion.

Purpose

This study aimed to evaluate the influence of different manufacturing procedures (Eli annealed – hot work versus cold worked – cold work) of the raw material under mechanical properties and morphological characteristics of orthodontic miniscrews (MS).

Material and methods

Thirty MS were randomly separated into 3 types (n = 10) according to manufacturer and manufacturing process of the raw material: type A – SIN® annealed (control group); type B – Dentfix® annealed; and, type C – Dentfix® cold worked. MI were inserted in artificial bone blocks, through the manufacturer's specific manual key attached to the digital torquemeter stabilized via custom device. Data of fracture's occurrence was performed using Fisher's exact test. Comparisons between the other two types regarding insertion torque and removal torque were performed using the Mann-Whitney test. Data of fracture torque, shear stress, normal stress and torque ratio was submitted to Kruskal Wallis and Dunn tests (α = 0.05). Representative images of surface morphology and fractures were selected.

Results

Type C showed statistically the lowest fracture torque (N.cm) (26.11 ± 0.41) (P = 0.0012) and highest torque ratio (%) (98.74 ± 0.85) (P = 0.0007). Type C showed statistically higher calculated shear (MPa) (2,432.73 ± 508.41) and normal stress (MPa) (1,403.86 ± 293.39) than type B and type A, showing that they differed in relation to the mechanical strength of the material with which they were made (P = 0.0007).

Conclusion

Type A fractured completely inside the most apical bone. Type B and type C fractured closer to the transmucosal profile. Cold worked process should be more prone to fractures than those annealed raw manufactured.