Journal of Orthodontic Science最新文献

Objective: To evaluate the effects of Lactobacillus paracasei probiotic toothpaste, cetylpyridinium chloride (CPC) toothpaste, and amyloglucosidase-glucose oxidase toothpaste on the levels of Porphyromonas. gingivalis, Aggregatibacter actinomycetemcomitans, and plaque index in individuals undergoing fixed orthodontic treatment.

Materials and methods: A double-blind randomized controlled clinical trial was conducted using purposive sampling. Participants were randomly assigned to use one of the toothpaste types. Saliva samples were collected at baseline and one month after using the toothpaste. Bacterial levels were quantified using quantitative polymerase chain reaction, and plaque accumulation was assessed using the Orthodontic Plaque Index.

Results: All groups showed a reduction of P. gingivalis and A. actinomycetemcomitans following the intervention; however, no significant changes were observed in the plaque index. Statistical analysis using two-way repeated measures analysis of variance with sphericity assumed revealed no significant differences between the groups (p < 0.05).

Conclusion: Toothpastes containing L. paracasei, CPC, and amyloglucosidase-glucose oxidase enzyme show potential for reducing periodontal pathogens, suggesting a preventive benefit against periodontal complications in patients with fixed orthodontic appliances.

Theoretical and anatomical pathways suggest a connection between the stomatognathic and visual systems. However, the evidence for associations between dental occlusion, temporomandibular disorders (TMD), and visual function is fragmented and of uncertain quality. This study aimed to systematically review and critically appraise the evidence regarding associations between occlusal factors, TMD, and visual parameters. We conducted a systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We searched MEDLINE (via PubMed) from 1946 to March 2025 for English-language studies investigating occlusion/TMD and visual outcomes. Two reviewers independently screened records, extracted data, and assessed risk of bias using the Joanna Briggs Institute (JBI) critical appraisal tools. A narrative synthesis was performed due to clinical heterogeneity. Ten studies (*n* = 7 cross-sectional, *n* = 2 case reports, *n* = 1 experimental) met the inclusion criteria. Evidence suggested associations between Class II malocclusion and myopia, altered masticatory muscle activity in myopia, abnormal pupillary responses in TMD, and vergence disorders in TMD patients. However, the overall body of evidence was rated as very low certainty due to pervasive methodological limitations: All studies had a high risk of bias, small sample sizes (20--150), and a cross-sectional design. Most studies originated from a single research group. While some associations between occlusal factors, TMD, and visual function are reported, the current evidence is insufficient to establish causality or clinical significance. The high risk of bias, small sample sizes, and lack of independent replication preclude definitive conclusions. Future high-quality, prospective, and adequately powered studies are required.

Background: Maxillary midline diastema (MMD) is a gap between the maxillary central incisors, posing cosmetic and psychosocial concerns for most patients. MMD results from multifactorial causes, including labial frenum, microdontia, genetics, and various oral habits. The purpose of this article was to review MMD, analyze its prevalence, describe a new shape-based classification, and identify potential causes with a focus on evidence-based practice.

Materials and methods: This cross-sectional descriptive study utilized orthodontic clinical records of Saudi adults aged 18-30 years who had not sought orthodontic treatment. MMD presence was confirmed by examining dental models. Diastema size was measured at gingival, middle, and incisal levels using a Mitutoyo calliper with 0.1 mm accuracy. Pairs of Angle Class I models were used to ensure equivalent tooth size for specimens. Patient records were reviewed to determine etiologies, and Bolton's tooth size ratio was calculated for analysis. Statistical analyses included Z-test, Shapiro-Wilk test, paired/independent t-tests, and post-hoc Bonferroni tests, conducted using SPSS version 26.

Results: The overall prevalence of MMD was 25% (n = 96), with 67% occurring in males. Among malocclusions, MMD prevalence was 42% in Class I, 32% in Class II, and 26% in Class III. MMD size distribution was 0.5-1 mm (18%), 1-2 mm (38%), and >2 mm (44%). A new shape-based classification identified trapezoidal (44%), triangular (40%), rectangular (12%), inverted triangular (2%), and biconcave (2%) forms. Major contributors included labial frenum elongation (25%), microdontia (19%), and midline shifting (72%). No significant differences in tooth sizes were found between MMD cases and Angle Class I controls (P > 0.05). Differences at the three measurement levels were negligible (P > 0.05) for both gender and malocclusion.

Conclusion: This study highlights the polygenic nature of MMD and introduces a new shape-based classification. Key predisposing factors, such as midline shift and microdontia, were identified. These findings will guide clinicians in treating patients diagnosed with MMD.

Objective: Assessment of total root volume, root length, labial bone height, and amount of intrusion for three different intrusive mechanics; orthodontic miniscrews, utility arch, and the nitinol reverse curve archwire (RCA).

Patients and methods: Twenty-one deep bite orthodontic patients (male and female, age range 12-16 years old), were involved in the current study. According to the method of intrusion for lower incisors, the patients were randomly subdivided into three groups; Group (A): patients received an intrusive force delivered by elastics from two mini-screws between mandibular lateral incisor and mandibular canine. Group (B): patients received an intrusive force delivered by intrusive utility arch. Group (C): patients received an intrusive force delivered by RCA. Cone beam computed tomography (CBCT) was taken just before and after completion of intrusion of the lower anterior segment. Statistical analysis was done with Statistical Package for Social Sciences (SPSS) version 18; Bonferroni's post hoc test was used for pair-wise comparisons when the ANOVA test is significant. The significance level was set at P ≤ 0.05.

Results: A statistically significant difference in root length reduction was found among the three groups. Post hoc analysis revealed no significant difference between group A and group B with mean difference (-0.97 mm, -0.93 mm). However, root length reduction in group A and group B was significantly greater than that of group C, which showed the least mean difference (-0.81 mm) in root length reduction.

Conclusions: The nitinol RCA produce adverse effects as a root resorption and reduction of labial bone height during intrusion of the lower anterior segment more than that produced by the orthodontic miniscrews with elastics and utility arch as intrusive mechanics.

Objective: This study aims to demonstrate the correlation between anterior tooth retraction and changes in the dimensions of the pharyngeal airway in cases of bimaxillary protrusion.

Materials and methods: Changes in dental parameters and the width of the upper and lower pharyngeal airways from 46 lateral cephalometric radiographs that met the inclusion criteria were measured. Changes were tested for significance using the paired t-test, and correlations were tested using the Pearson correlation test.

Results: Significant changes were observed in dental parameters and in the width of the upper pharyngeal airway following orthodontic treatment (P < 0.05). However, no significant change was found in the width of the lower pharyngeal airway (P = 0.166). There was no significant correlation between changes in the upper incisor parameters and upper pharyngeal airway width (P = 0.130 and P = 0.738), nor between changes in the lower incisor parameters and lower pharyngeal airway width (P = 0.911 and P = 0.614).

Conclusion: Anterior tooth retraction does not significantly correlate with changes in the width of the pharyngeal airway. Therefore, premolar extraction for anterior tooth retraction can be considered a safe orthodontic approach in cases of bimaxillary protrusion.

Objective: To assess the diagnostic accuracy of artificial intelligence-based models in the determination of tooth extraction in orthodontic treatment planning.

Materials and methods: A comprehensive literature search was conducted in multiple databases (PubMed, LILACS, Web of Science, Scopus, EBSCO, and Google Scholar) up to June, 2024. Studies that met the inclusion criteria based on the PIRD (Participants, Index test, Reference test, Diagnostic) framework were selected. The risk of bias of included studies was assessed using the QUADAS-2 tool, and their methodological quality was evaluated as well using a standardized checklist.

Results: Out of 361 retrieved records, eleven studies were included in this review. Nine of these studies achieved a score of over 50% on the AI quality checklist, indicating acceptable methodological quality. However, a comprehensive assessment using the QUADAS-2 tool revealed that all studies had some level of risk of bias, particularly in patient selection, the conduct of AI-based predictions, and the reference standard used.

Conclusion: Neural networks and classifier models demonstrated the high level of accuracy ranging from 82% to 94% in determining the optimal tooth extraction protocol. However, to ensure reliable predictions, artificial intelligence-based models should be rigorously trained, incorporating a comprehensive range of factors.

Objective: To evaluate and compare the expression levels of Receptor Activator of Nuclear Factor Kappa B Ligand (RANKL) and Osteoprotegerin (OPG) in canine periodontal tissues subjected to periodontal distraction versus conventional retraction at different treatment time points.

Materials and methods: The study involved 40 cuspids from 20 patients (9 males, 11 females) randomly allocated to either the periodontal distraction (PD) group or the conventional retraction group. Appliances were applied by a single practitioner in a split-mouth design. In Group 1 (PD), a trans-palatal arch and Hyrax expanders were used following premolar extraction with osteotomies performed to facilitate distraction. Group 2 (conventional retraction) used MBT brackets with sectional archwires and elastic chains. Gingival crevicular fluid samples were collected on the first day (D0), after 1 week (W1), and 6 weeks (W6) and OPG and RANKL levels were analyzed using ELISA test.

Results: There was a significant difference in canine retraction duration between methods (P < 0.001), with periodontal distraction taking 24.1 ± 2.08 days versus 110.5 ± 4.84 days for conventional retraction. RANKL levels showed no baseline difference, but were significantly higher in the periodontal distraction group at weeks 1 and 6 (P = 0.010 and P = 0.001, respectively). OPG levels were initially similar, but by weeks 1 and 6, they were significantly lower in the periodontal distraction group (P = 0.001).

Conclusion: The periodontal distraction method significantly reduces the duration of canine retraction and enhances osteoclastic activity, as evidenced by increased RANKL and decreased OPG levels, facilitating accelerated tooth movement through efficient bone resorption and remodeling.

Objective: This scoping review aims to evaluate the efficacy and limitations of clear aligner therapy (CAT), particularly Invisalign, in the transverse development of the maxillary arch. With increasing demand for esthetic, removable orthodontic alternatives, clear aligners are used beyond mild crowding to manage arch expansion and crossbites.

Materials and methods: A comprehensive search of PubMed, Scopus, Web of Science, Google Scholar, Elsevier, and National Center for Biotechnology Information was conducted to identify English-language studies published between 2020 and 2024. Keywords used included "maxillary arch development," "CAT," and "Invisalign." After applying inclusion and exclusion criteria, eight studies were included from an initial 3,190 identified records. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework guided the selection process.

Results: The included studies demonstrated that clear aligners can achieve maxillary expansion primarily through buccal tipping of posterior teeth. However, bodily movement remains limited. The predictability of expansion outcomes varied, with cusp width changes being more reliable than root or gingival-level movements. One study found an expansion efficiency of over 90% at the first premolar cusp, while others noted discrepancies between planned and achieved outcomes.

Conclusion: Clear aligners demonstrate moderate effectiveness for maxillary arch expansion through dental tipping, especially in mild to moderate cases. However, they are less predictable for bodily movement or large-scale skeletal changes. Further high-quality, controlled trials are required to validate these outcomes and optimize treatment protocols.

Class III malocclusion in mixed dentition often involves maxillary retrusion. Conventional orthopedic treatments, such as facemask or chin cup therapy, aim to redirect craniofacial growth but frequently cause dentoalveolar compensation and unfavorable vertical changes. Bone-anchored maxillary protraction (BAMP) provides skeletal traction to enhance maxillary advancement while limiting vertical side effects. This review compares the skeletal, dentoalveolar, and soft-tissue outcomes of BAMP versus conventional orthopedic treatment or natural growth in children under 12 years. The protocol was prospectively registered in PROSPERO (CRD420251042103). A systematic search of PubMed, Scopus, Embase, Web of Science, and the Cochrane Library was conducted up to April 2025 following PRISMA 2020 guidelines. Studies evaluating BAMP against conventional Class III therapies or untreated controls in children younger than 12 years were included. Four quantitative and four qualitative studies were synthesized. Risk of bias was assessed using RoB 2.0 and ROBINS-I. Across 116 patients in the quantitative studies, BAMP consistently improved SNA (+1.9° to +6.17°) and ANB (+1.4° to +6.83°), enhanced Wits appraisal, and demonstrated minimal increases in SN-MP angles, indicating superior vertical control. Overjet gains (+5.97 mm) and stable upper incisor inclination suggested reduced dental compensation. Soft-tissue improvements included enhanced midface projection. The qualitative studies supported these trends. Current evidence indicates that BAMP achieves greater skeletal correction and vertical control with fewer dentoalveolar side effects compared with conventional Class III therapies or observation. Further long-term studies are required.

Introduction: Cephalometrics is the most frequently utilized clinical tool for assessing sagittal jaw relationships. There have been numerous linear and angular measures employed to diagnose these anteroposterior discrepancies. Each of the methods demonstrates its intrinsic characteristics based on the variation of variables besides the jaw relationship itself. The objective of this study is to make a comparative evaluation of 23 parameters, which includes linear and angular measurements of sagittal discrepancy in detail.

Materials and methods: About 150 lateral cephalograms were gathered from subjects obtained in natural head position. This comparative study evaluated the mean and standard deviation, the reliability, and the correlation between various parameters and their sensitivity and specificity were calculated.

Results and conclusion: All the measurements are statistically highly significant in determining the sagittal skeletal discrepancy. Recent angles like Beta angle, Yen angle, and Pi analysis have lots of accuracy and consistency associated with them. However, the human population exhibits significant variability, making it impossible for a single cephalometric examination to reliably determine true skeletal relationships in every circumstance. Therefore, the spectrum of cephalometric analysis must be understood by clinicians so that it can be used appropriately according to the patient's needs.