Journal of Orthodontic Science最新文献

Objective: To determine the effect of the nose and chin on the cephalometric lip profile.

Methods and material: The pre-treatment lateral cephalograms of 177 adult patients with no history of orthodontic treatment were manually traced. The sample size was divided into three vertical and horizontal groups using angle ANB and MMA to assess the difference in nose and chin forms. The horizontal and vertical groups were analyzed using One-way ANOVA and Kruskal-Wallis. The Independent sample t-test and Mann-Whitney U were used for comparison between the two genders. The correlation of nose and chin with E, S line, and nasolabial angle was done using the Spearman correlation coefficient while the effect was assessed using linear regression analysis.

Results: Among the nasal variables, columellar length inversely affects the linear position of the upper lip and this was statistically significant. The nasolabial angle is also affected by the inclination of the nasal base and this was statistically significant. The linear distance of the soft tissue chin in relation to the maxilla has the most effect on the position of the upper lip. It is notable that all hard and soft tissue chin variables inversely affected the linear position of the upper and lower lips.

Conclusions: The quantitative measure of the effect of the nose and chin on lips is important as it allows clinicians to determine the overall effect of adjunctive procedures at pretreatment levels. Thus, corrective procedures such as rhinoplasty or genioplasty can be done at pre-orthodontic treatment stages to create a better treatment plan for patients.

Context: The mandibular canal (MC) is an essential landmark that should be considered before any surgeries. Therefore, accurately assessing the location and characteristics of the MC in cone beam computed tomography (CBCT) imaging is very important.

Aims: To determine the characteristics of the MC in relation to adjacent anatomical structures in CBCT projections.

Settings and design: The convenience sampling method.

Methods and material: This was a retrospective study of 112 CBCT images of Vietnamese patients aged 18 to 69 years, taken for clinical indications between 2018 and 2023. The evaluation was carried out by comparing and arranging the anatomical structures of different planes in three-dimensional space to assess and measure relevant dimensions.

Statistical analysis used: Independent samples T-test.

Results: The average diameter of the MC from the apex of the second premolar to the distal apex of the second molar, if there were no missing teeth in this segment, was 2.58 ± 0.52 mm (right) and 2.55 ± 0.54 mm (left). If there were a missing tooth in this segment, the measurements were 2.51 ± 0.79 mm (right) and 2.47 ± 0.45 mm (left). The difference between the two sides regarding the presence or absence of a missing tooth was not statistically significant.

Conclusions: The precise localization of the MC related to the tooth apex and the diameter of the MC can vary in each person. CBCT indications should be considered when establishing treatment planning to avoid damaging the inferior alveolar nerve in the MC.

Aim: The aim of this study was to make a laboratory assessment of pH influence on the kinetics of the release of nickel ions in artificial saliva.

Methods and material: In this study, 15 basic orthodontic appliances are immersed in 15 polyethylene tubes each containing 40 ml of artificial saliva. Tubes were divided into three sub-groups of 5 tubes depending on the pH: pH 5, pH 7 and pH 8. The release of nickel ions was measured using atomic absorption spectrometry in a sample of 5 ml of artificial saliva taken one hour, four hours and one hundred and sixty-eight hours after immersion in a water bath at 37°.

Statistical analysis used: Significance threshold P was set at 0.05. A Student T test and the 2-way Anova test (with a Bonferoni post-test) were used respectively to compare the means.

Results: The neutral pH causes a low release of nickel ions. The release kinetics of nickel ions is minimal for neutral pH, it increases when pH varies. After one hour of immersion, the nickel released did not reach the spectrometer quantification threshold as for neutral and acid pH. The alkaline pH causes an average release of nickel ions from the beginning without kinetic variation. As time passes (T3), the acidic pH causes more nickel ions release through a succession of oxidation-reduction reactions. After 168 hours, the average mass of nickel released is 0.30 µg for pH 7, 1.35 µg for pH 8 and up to 2.85 µg for pH 5.

Conclusions: Quantities released did not reach nickel toxicity threshold in humans. Orthodontists must consider the potential risk of hypersensitivity due to nickel in fixed orthodontic appliances.

Background: Bullying has a lasting effect on young, vulnerable minds, especially among school-aged youngsters. With the help of this study, we intended to examine how physical and dentofacial characteristics contribute to bullying among kids and how it affects their academic performance.

Methods: This retrospective cross-sectional study consisted of a self-reported anonymous, pretested questionnaire divided into three major domains, with due institutional ethical clearance being obtained before the study's commencement.

Results: The study population consisted of 269 schoolchildren, with 49.8% being males and the majority (55.0%) residing in Ajman. Among the schoolchildren, 35.7% reported being victims of bullying. The majority of bully victims (27.1%) skipped school because of bullying. Additionally, 64.3% of the students had a nickname, primarily used by siblings, and approximately half of the bully victims disliked their nicknames. In terms of happiness, 45.0% of students were neither happy nor unhappy in classes, while 10.8% were very unhappy. Outside of school, 56.9% of participants were very happy, and only 1.1% were very unhappy. Most students (58.7%) did not believe that bullying harms their grades, while 19.7% believed it does. Furthermore, 71.7% of students did not experience bullying due to good grades or showing interest in schoolwork.

Conclusion: Based on results, physical and dentofacial features in bullying among schoolchildren and its impact on school performance, sociodemographic patterns, and factors associated with bullying victimization highlight the need for targeted interventions and preventive strategies to address this issue. Thus, can create a safe and supportive school environment that promotes the well-being and academic success of all schoolchildren.

Objective: To evaluate and compare the skeletal and dental treatment effects of Class II malocclusion cases using skeletally anchored Forsus (miniscrew-anchored FRD or miniplate-anchored FRD), with conventional Forsus FRD.

Materials and methods: Unrestricted electronic search of six databases and additional manual searches were performed up to July 2023. Randomized controlled trials having one treatment arm with skeletal anchored Forsus FRD in treatment of Class II malocclusion and another matched treatment group treated with conventional Forsus FRD were included in this review. Risk of bias assessment was performed using Cochrane's Risk of Bias Tool. No restrictions were set concerning treatment duration, or the cephalometric analysis used. Skeletal and dentoalveolar outcomes data were extracted by two authors independently.

Results: Three studies using miniscrews as means of skeletal anchorage were evaluated and qualified for the final review and meta-analysis. Three other studies using miniplates were considered in the systematic review but were not qualified for a meta-analysis. The data gathered from the miniscrews anchored FRD papers included a total of 93 Class II patients (46 treated with miniscrew-anchored Forsus FRD, 47 treated with conventional Forsus FRD). The meta-analysis showed a statistically significant reduction in the SNA angle in favor of miniscrew-anchored Forsus FRD (mean difference: -0.26, CI: -0.50 to -0.02), a nonsignificant difference in the SNB (mean difference: 0.17, CI: -0.06 to 0.39), a statistically significant increase in the SN-MP angle in favor of miniscrew-anchored Forsus FRD (mean difference: 0.53, CI: 0.06-1.00)-a statistically significant reduction in the L1-MP angle in favor of miniscrew-anchored Forsus FRD (mean difference: -2.12, CI: -4.96 to -2.12). Data from miniplate-anchored FRD included 31 Class II patients treated with mini plate anchored FRD. Although meta-analysis was not applicable to these studies, lower incisor inclination was observed to be less.

Conclusions: Based on the existing evidence, the use of skeletal anchorage could not enhance forward mandibular growth. However, miniscrew-anchored Forsus FRD could minimize mandibular incisor protrusion while miniplates could even retract the mandibular incisor position with a headgear effect on the maxilla.

Objectives: As patients are instructed to wear thermoplastic retainers for the rest of their lives, the durability of the materials is a critical factor in evaluating whether the expense is justified. This study examined the physical and mechanical properties of three different thermoplastic retainer materials before and after thermoforming (BT and AT).

Materials and methods: Clear Advantage Series I, Clear Advantage Series II, and Leone types were used, with each material having a thickness of 1 mm. The materials' tensile force, hardness, and water absorption tests have been measured for 90 thermoformed and 90 non-thermoformed specimens (30 specimens from each material).

Results: The tensile force, hardness, and water absorption values of all the materials differed significantly (P ≤ 0.05) BT. Additionally, the majority of the materials showed significant differences in water absorption, hardness, and tensile force (P ≤ 0.05) AT, except the Leone materials, and Clear Advantage Series I did not significantly differ in the case of hardness value. All studied materials showed an increase in hardness and water absorption AT (P ≤ 0.05). At the same time, all of the studied materials showed a significant decrease in tensile force after thermoforming.

Conclusion: Thermoforming increases the material's water absorption while decreasing its stiffness, affecting its mechanical and physical properties. Clear Advantage Series II (PP) stood out with superior flexibility, wear resistance, and minimal water absorption compared to other materials, highlighting its durability and superiority.

Objectives: To evaluate the effectiveness of mini-implant (MI) anchorage versus conventional anchorage for the treatment of skeletal class II malocclusion.

Materials and methods: The study was conducted on 64 patients with skeletal class II malocclusion. The patients were divided into two groups: 1) 32 patients underwent conventional anchorage, and 2) 32 patients underwent MI anchorage. Cephalometric radiographs were taken pre-treatment, and the data were compared with post-treatment measurements.

Results: The age and gender distribution between the conventional and MI anchorage groups was similar, and the differences were statistically significant. The SNA and SNB angles post-treatment were reduced compared to pre-treatment measurements in both groups. The MI anchorage demonstrated a superior subsidence effect, reducing the level of forward displacement of the first molars in the maxilla. The MI group also exhibited less extrusion of the molars compared to the conventional group. In skeletal class II cases, especially in patients with a high mandibular angle using MI anchorage helped prevent the mandible from rotating counterclockwise, thus improving aesthetics rather than worsening them after treatment. In 75% of the cases in the MI anchorage group, the outcome was assessed as "greatly improved" based on the PAR index.

Conclusions: MI anchorage was more effective than conventional anchorage. It allows for greater posterior movement and intrusion of the maxillary incisors while maintaining or rotating the mandibular plane counterclockwise.

The era of printed aligners has just began in the orthodontic field. Orthodontists have become more interested in 3D-printed in-office aligners. Treatment due to this technology can become faster and more efficient. Advantages highlighted by newly introduced materials for manufacturing processes of 3D aligners present the possibility of overcoming limitations faced by thermoformed aligners, making them a potential replacement of thermoformed aligner. Advances in aligner material, especially shape memory polymers, have the potential to bring about radical transformations in the clinical applications of clear aligner therapy. Safety and cytotoxicity of printable resins along with its mechanical properties must be scientifically studied extensively before it is cleared for clinical use. In addition, with the increased use of aligners, awareness of the environmental burden of plastic waste should be emphasized. Attention should be directed into the development of recyclable materials for aligners along with establishing clear recycling guidelines and patient education programs on proper recycling methods. With the introduction of Graphy's clear biocompatible photocurable resin, which is equipped with a shape-memory function and is printed in an environmental friendly way by reducing carbon emissions. Direct 3D printing represents the future of clear aligner therapy, and more studies to test these new technologies and materials are required.

Objective: This study aimed at determining the effect of pH changes on nickel titanium wire seen based on the corrosion rate and surface roughness of the wire after immersion in pandan leaves extract.

Material and methods: The sample used nickel titanium wire of 0.016 inches diameter and 5 cm length and consists of five treatment groups: control group, 0.2% chlorhexidine, and 1000 ppm, 2000 ppm, and 4000 ppm pandan leaves extract. The solutions were put into an incubator for 7, 14, and 21 days at 37 °C and removed according to the sample immersion time. The corrosion rate was determined using the weight-loss method, and microstructure roughness was analyzed using a scanning electron microscope.

Results: Kruskal-Wallis test showed that there was a significant difference in corrosion rate of orthodontic wires of nickel titanium after control submersion, 0.2% chlorhexidine, and pandan leaves extract on 7, 14, and 21 days (P ≤ 0.05), and pandan leaves extract submersion shows that the surface structure is not as bad as artificial saliva and 0.2% chlorhexidine.

Conclusions: Pandan leaves extract could inhibit the corrosion rate of nickel titanium orthodontic wire, which might be due to tannin content as an active antioxidant.

Objective: This study aimed to comparatively evaluate the perceptions of laypeople and orthodontists regarding the usefulness of orthodontic practice websites (OPWs) and Internet-based social media (ISM) and to assess whether the content, features, and design of these online information sources meet the expectations of laypeople compared to orthodontists.

Material and methods: A cross-sectional, nationwide study was conducted using a pretested and validated electronic questionnaire administered separately to specialist orthodontists and laypeople. A total of 136 orthodontists and 1038 laypeople voluntarily participated. The willingness of specialists to adopt a modern approach to promoting OPWs is explored, and the essential information that should be included in ISM is identified.

Results: Most orthodontists (52.9%) and laypeople (88.2%) preferred face-to-face communication over online content searching. Both groups consistently identified "contact details" and "types of treatment" as crucial information to be presented on OPWs. Facebook and Instagram were the most popular platforms among both orthodontists and laypeople.

Conclusions: Both specialist orthodontists and laypeople should increasingly utilize OPWs due to their comprehensive benefits.