Journal of Orthodontic Science最新文献

Objective: To evaluate the efficiency of the self-etch primer co-curing protocol in retaining orthodontic brackets to tooth enamel.

Materials and methods: A self-etch orthodontic resin primer was pre-cured or co-cured together with the resin adhesive (Groups 1 and 2) to retain either non-coated or pre-coated orthodontic brackets (Subgroups 1 and 2) on the buccal surfaces of extracted premolars. The debonding shear stress values were evaluated immediately after bonding (Category 1) and after exposure to cyclic intraoral hydraulic, thermal, and mechanical stress simulations (Category 2). The adhesive remnant index (ARI) was also assessed for each test category.

Results: The co-cured primer provided higher immediate debonding stress values for both non- and pre-coated brackets (Tukey's, P < 0.05) than the pre-cured primer. However, after artificial aging and stress simulation, there was no difference in bonding values for the four test categories (Tukey's, P > 0.05). The delayed debonding stress values were lower than the immediately assessed values (Tukey's, P < 0.05) for both brackets. No difference (Mann-Whitney's, P > 0.05) was noticed in the ARIs of all test categories.

Conclusion: Although intraoral stress simulation reduced the brackets' debonding values, co-curing the self-etch orthodontic primer may offer clinically efficient bonding of both non- and pre-coated metal brackets with minimal harm to tooth enamel on debonding.

Introduction: Jaw mobility and oral function depend on the temporomandibular joint (TMJ), with the dimensions of the mandibular condyle and glenoid fossa being important for understanding dental and orthodontic conditions. Additionally, advanced imaging, like cone-beam computed tomography (CBCT), has improved the study of condylar morphology, aiding diagnosis and treatment planning.

Aim: To perform morphometric analysis of the TMJs using CBCT in all three dimensions in various skeletal malocclusions.

Materials and methods: CBCT images of 84 patients were collected for the study. FACAD (ILEXIS AB, Linköping, Sweden) software was used to divide the patients into Class I, II, and III skeletal malocclusions. Dolphin software was used to measure the width, length, and height of condyles and glenoid fossa of the patients from the CBCT images. The Shapiro-Wilk test was used to check normality. ANOVA test was performed to assess the statistical significance of the results between the 3 groups.

Results: The sample consisted of 30 patients with class I skeletal relation, 34 patients with class II relation, and 20 patients with class III relation. In class I relation, the average condylar height is found to be 16.32 mm ± 2.16 mm, width is 16.47 mm ± 2.61 mm, and length 7.65 mm ± 1.5 mm. The average dimensions of the glenoid fossa in class I skeletal relation were measured to be 19.93 mm ± 2.64 mm in width, 13.93 mm ± 1.45 mm in length, and 6.4 mm ± 1.49 mm in height.

Conclusion: A statistically significant difference was noted in the condylar width and condylar height among the various skeletal malocclusions. The morphological parameters assessed in this study require more investigation to fully understand the mechanisms underlying them and investigate the consequences for orthodontic treatment and TMJ health.

Objective: The aim of this study was to evaluate the prevalence of canine transmigration and impaction among patients at a tertiary dental health care center in India, using panoramic radiographs, and to introduce a novel classification system for mandibular canine transmigration.

Materials and methods: A retrospective analysis of digital orthopantomograms (OPGs) of 30,000 patients above the age of 12 years, obtained from a tertiary dental health care center was conducted to assess the prevalence of canine transmigration and canine impaction.

Results: A total of 30,000 OPGs were examined, revealing 341 transmigrated canines, with an overall prevalence of 1.1%. Transmigration was more common in the mandible (246 canines, 0.8%) than in the maxilla (95 canines, 0.3%), and slightly more prevalent in females, though not statistically significant. In the mandible, 235 cases were unilateral and 11 were bilateral. All maxillary cases were unilateral. The 246 transmigrated mandibular canines were categorized using the new MBS classification system: Group I (117), Group II (100), Group III (16), Group IV (2), and Group V (11).

Conclusions: Canine impaction was more prevalent in the maxilla, whereas transmigration was more prevalent in the mandible. The MBS classification system showed the highest prevalence in Group I (oblique), followed by Group II, with the lowest in Groups III (vertical) and Group IV. This system provides a more detailed and clinically useful framework than previous classifications.

Objective: Canine impaction isn't uncommon malocclusion and their treatment is complex and annoying to both patient and orthodontist. This study was aimed to determine the prevalence of impacted canine in orthodontic patients of Fallujah city with determining the related etiological factors.

Materials and methods: The study consisted of 590 patients (412 females and 178 males) coming to the clinic for orthodontic treatment. A panoramic radiograph was taken for each subject. Cone beam computed tomography was taken for each patient with an impacted canine for accurate localization of trapped teeth. Patients with impacted canines were examined for number, distribution, crown depth, angulation and apical position of impacted teeth, lateral incisor condition, and presence of associated local factors.

Results: For the total sample, forty patients (40) had impacted canines with a mean age of 22.6 years. Female to male ratio was 1.5:1. The maxilla represented 80.6% of total impaction cases. Palatally impacted canines represented 72.6% and were mostly seen bilaterally. The mandible formed 19.4% of impacted canines. Mesially and vertically angulated impacted teeth represented the majority of the cases for upper and lower jaws respectively. The impaction depth was recognized as D2 at the maxilla and D1 at the mandible as the commonest impaction level. Apical mislocation was presented in 21% of cases.

Conclusion: The prevalence of impacted canines was 6.8%. Retained primary canines were associated with 76% of total impacted canines. About 32% of total maxillary impacted canines were associated with anomalous or missing lateral incisors.

Introduction: In recent years, Saudi Arabia has experienced a considerable increase in the yearly inflow of dentistry graduates. This has led to expectations of a corresponding increase in postgraduate study applications. Consequently, postgraduate program directors have been compelled to continuously refine their selection criteria, using a combination of objective and subjective measures. Despite the importance of the topic, very little research exists on the selection process for orthodontic programs. Moreover, no studies have been performed to investigate this process in Saudi Arabia. This study aims to describe the applicant selection criteria for orthodontic specialty programs in Saudi Arabia, offering insights from the perspectives of orthodontic program directors.

Method: This study surveyed orthodontic program directors in Saudi Arabia to collect data on program operations, application details, the interview process, selection criteria, and demographic characteristics of program directors. A self-administered questionnaire, distributed through Google Forms, was used to collect responses. Statistical analyses included descriptive statistics and ranking of responses.

Results: The majority of programs (75%) were located in hospitals, primarily in central and western Saudi Arabia. Interview ratings, class rank, and recommendation letters were the most influential factors in the selection process, with research experience and clinical attachments also playing an important role. Interviews were mandatory and typically lasted 15 min. Positive applicant characteristics included maturity, professional attire, and analytical thinking skills. Selection committees, composed of program directors and faculty members, held primary responsibility for admitting applicants.

Conclusion: This study offers valuable insights for dentists aiming to apply for the Saudi Board of Orthodontics. Gaining a clear understanding of the selection criteria, prioritizing training in preferred orthodontic departments, and emphasizing research in orthodontics can improve applicants' chances. The findings aim to enhance the transparency and fairness of the selection process, ultimately strengthening orthodontic education in Saudi Arabia.

Background: Contemporary society places a strong emphasis on the importance of facial esthetics. This perception of esthetics is inherently related to facial symmetry. Esthetics of soft tissues plays an important role in the selection of the therapeutic strategy; thus, the subjective evaluation of chin asymmetry is of great significance for clinical treatment.

Aim: The objective of the study is to evaluate: 1. The degree of chin asymmetry on esthetics perception in frontal view and 2. To analyze the critical evaluation of chin asymmetry by dental professionals and laypersons with frontal facial photographs.

Methodology: Chin asymmetries were analyzed through a series of edited frontal photographs of two subjects (male and female). The position of the chin was digitally altered from 0° (no alteration) to 6° (most severe alteration). Participants' responses were collected from laypersons (n = 100), general dentists (n = 50), and orthodontists (n = 51), and the photographs were graded according to esthetic appeal using a visual analog scale. Statistical analysis showed the diagnostic threshold levels for identifying chin asymmetries.

Results: General dentists and laypersons showed similar threshold for diagnosing chin asymmetry in male and female subjects of 4°, whereas orthodontists could diagnose transverse chin asymmetry in male and female subjects at a 3° deviation. All the groups rated the 0° and 1° as the most attractive and 5° and 6° as the least attractive.

Conclusions: Laypersons and general dentists had a relatively same accuracy in diagnosing transverse chin asymmetries in both female and male subjects, whereas orthodontists have relatively higher accuracy compared with other groups.

Aim of the study: This research paper was intended to quantify the stresses and the displacement distribution pattern released by Omega-loop transpalatal arch (TPA) activated in the Burstone geometries (II, III, and V) within two different materials.

Materials and methods: Three-dimensional solid models of the maxilla and maxillary teeth were created using CBCT data for a 20-year-old man. A molar band and Omega-loop TPA were constructed. Force application was pretended virtually to geometry II, III, and V within stainless-steel and Armco β-titanium (TMA) (titanium-molybdenum-aluminum) material.

Results: The schemes for stresses and the displacements were alike for both stainless-steel and TMA alloy Omega-loop TPAs. The stresses and displacements for the stainless-steel Omega-loop TPAs were higher than those for the TMA. Mesial tipping was seen in the unit with a large moment, distally in the opposite side. The highest displacement values were seen around the x-axis, which represent the tipping molar movement.

Conclusions: This study results have shown that Omega-loop TPA can effectively derotate upper first molars. Anchorage reinforcement for the opposite molar should be kept in the orthodontist mind to avoid the unwanted movement as a result of the reactive forces for the active unit, especially when it is decided to use a high force to correct unilateral molar rotation.

Context: Numerous studies worldwide have shown that there is a significant difference between tongue volume and pharyngeal airway volume in skeletal patterns Class I, Class II, and Class III. It is closely related to the position, size of the jaw bone and volume of the oral cavity. This distinction plays an important role in orthodontic evaluation and treatment planning, especially in patients at risk for airway obstruction during sleep.

Objective: To evaluate the volume of the tongue and pharyngeal airway in adults with different malocclusion conditions, in order to clarify the relationship between tongue volume, pharyngeal airway volume and oral cavity volume.

Material and methods: A cross-sectional descriptive prospective study analysis was conducted on 120 patients with varying skeletal patterns who sought examination and treatment at the Department of Dentistry and Maxillofacial Surgery, Can Tho University of Medicine and Pharmacy Hospital. Imaging data from these patients were used to evaluate the volume of the tongue and pharyngeal airway in adults with different malocclusion conditions.

Results: The average volumes of TV (Tongue volume) and TPV (Total pharynx volume) in Class III malocclusion were the largest, with values of 57820.86 cm³ and 28385.33 cm³, respectively. In contrast, the smallest volumes were observed in Class II, with values of 50380.48 cm³ and 23414.58 cm³, respectively.

Conclusions: An inverse correlation has been established between the TV/OCV (Tongue volume/Oral cavity volume) ratio and pharyngeal airway volume. This finding suggests that tongue volume, oral cavity volume, and their ratio influence airway patency. Understanding the relationship between the tongue and the airway in orthodontic treatment planning, particularly in improving airway space for patients with Class II malocclusion.

Objective: Literature suggests that the mode of ligation and use of elastomeric chains for achieving orthodontic space closure may result in a significant increase in microbial colonisation. The objective of the present study was to evaluate and compare the rates of microbial colonization on nickel-titanium (NiTi) closed-coil springs and active tie-backs used for orthodontic space closure in the maxillary premolar extraction site.

Materials and methods: Thirty-two participants, including 14 males and 18 females, were enrolled in the present split-mouth study. In Group I, NiTi closed-coil springs (Nitinol, 3M Unitek) were used, while in Group II, active tie-backs [stainless steel ligature wire (0.009') threaded through an elastic module (3M Unitek) were used. After a period of 3 weeks, the NiTi closed-coil springs and active tie-backs were carefully removed and transferred to brain heart infusion broth (BHI Broth). The BHI broth samples were then incubated and inoculated into different media, followed by sub-culturing with various specific media. The colony-forming unit per millilitre were measured using a colony counter (HiMedia Laboratories Private Limited, Mumbai, Maharashtra, India). Finally, the various isolated colonies were submitted for phenotypic characterization using BIOMÉRIEUX VITEK^® MS, an automated mass spectrometry microbial identification system based on proteomics-based detection.

Results: The observations made in the study suggested an increased number of microbial colonies in the NiTi closed-coil spring group (46437.50 ± 11848.34 CFU/mL) compared to the active tie-back group (31031.25 ± 8204.97 CFU/mL), with the difference being statistically highly significant (P < 0.000).

Conclusion: Based on the findings of the present study, it can be concluded that using active tie-backs resulted in significantly reduced pathogenic adherence compared to NiTi closed-coil springs. However, further research is necessary to validate these findings before active tie-backs can be recommended as a suitable means for orthodontic space closure, especially in patients with compromised oral hygiene due to any given reason.

Objective: The goal of this study was to determine the prevalence of midline shift in relation to gender, location, and classification of malocclusion.

Material and methods: A total of 150 dentistry students aged 18-25 (93 females and 57 males) were picked at random from Mustansiriyah University. Dental midline shifting is evaluated by comparing the positions of the maxillary and mandibular dental midlines to the face midline, with the philtrum serving as a reference point.

Results: About a quarter of the total sample had dental midline shift (26%) which was more prevalent in mandibular arch. The prevalence of dental midline shift was more common in females (60,5%). In general, dental midline deviation was more common in angle's Class I and Class II than Class III, while for the maxillary arch, it was common in angle's Class I and Class II, Divison 1, and for the mandibular arch, it was more common in angle's Class I and Class III. The deviation was more common to the right side in both arches.

Conclusions: A quarter of the total sample had dental midline shift, most of them were females, and the deviation was more common in the mandibular arch in Class I angle's classification.