Journal of Orofacial Orthopedics-Fortschritte Der Kieferorthopadie最新文献

Background: The present study aimed to assess the frequency and variation of 13 nonmetric dental crown traits (NDCT) in permanent and primary molars in German orthodontic patients.

Methods: Dental records from orthodontic patients were screened and evaluated. First and second permanent and primary upper and lower molars (from left and right sides) were assessed. Teeth with cavitated dental caries, occlusal wear, restorations and obvious dental deformities were not evaluated. The NDCT for permanent molars were identified and scored according to the odontoscopic system developed by Arizona State University Dental Anthropology System (ASUDAS). The NDCT for primary molars were identified and scored according to ASUDAS, Hanihara's method and Sciulli's method. The χ² test was used to investigate side preference and sexual dimorphism at a significance level of p ≤ 0.050.

Results: A total of 163 orthodontic patients (82 males and 81 females) aged 8-14 years were included. A sexual dimorphism was observed for the hypocone in first upper permanent molar (p = 0.041). The protostylid was observed in lower permanent molars (range 2.1-10%). Males presented more hypoconulid than females (p = 0.019). Only females presented the distal trigonid crest in lower first permanent molars (p = 0.002). The most common groove pattern in primary molars was Y; male presented more Y grade than females in the lower second primary molar (p = 0.039). Asymmetry was observed in some traits, ranging from 0 to 100%.

Conclusion: The present study showed the frequency of NDCT of molars in German orthodontic patients and demonstrated that some traits present sexual dimorphism.

Background: Acceleration of tooth movement has gained remarkable attention during the last decade. The aim of this study was to evaluate the effect of low-level laser therapy (LLLT) on en masse retraction of upper anterior teeth in adult women with bimaxillary dentoalveolar protrusion.

Materials and methods: In this two-arm parallel trial, 36 women with bimaxillary dentoalveolar protrusion were randomly divided into two equal groups. Eligibility criteria included class I Angle molar relationship, good general and oral health as well as no systemic disease or syndrome. Four temporary anchorage devices (TADs) were used in the upper and lower arches for anchorage purposes. A 0.019×0.025-inch stainless steel wire with crimped hooks just distal to the maxillary canines was inserted. Nickle titanium (NiTi) closed coil springs (200 g/side) were employed for en masse retraction following extraction of the first premolars. In the laser group (LG), retraction of the upper anterior teeth was done along with the application of LLLT on days 0, 3, 7, and 14 after extraction and then repeated biweekly until the end of retraction. Retraction was completed without LLLT application in the nonlaser group (NLG). Data concerning the rate of retraction as well as first molars and anterior positional changes were gained from digitized models and cone beam computed tomography (CBCT) scans taken just before extraction and at the end of retraction. Treatment-associated pain and root resorption were evaluated using visual analogue scale (VAS) and CBCT scans, respectively.

Results: Four patients dropped out prior to follow-up. The duration of retraction was 10.125 ± 2.876 and 13.643 ± 3.455 months in the LG and NLG, respectively. The LG showed a statistically significant faster rate of en masse retraction (0.833 ± 0.371 mm/month) compared to the NLG (0.526 ± 0.268 mm/month; P ≤ 0.035). The observed root resorption was significantly less in the LG (P ≤ 0.05) with comparable pain scores in both groups.

Conclusions: Within the constraints of the parameters of the LLLT used in the current study and despite the statistically significant results on the rate of en masse retraction and the associated root resorption, LLLT did not demonstrate a clinically relevant effect that justifies its use to enhance en masse retraction.

Name of the registry: Clinicaltrials.gov TRIAL REGISTRATION NUMBER: NCT05183451 DATE OF REGISTRATION: January 10, 2022, "Retrospectively registered" URL OF TRIAL REGISTRY RECORD: https://www.

Clinicaltrials: gov/study/NCT05183451.

Purpose: The purpose of this study was to analyze the biomechanical effects of four different designs of frog appliances for molar distalization using finite element analysis.

Methods: A three-dimensional finite element model including complete dentition, periodontal ligament, palatine, and alveolar bone was established. Four types of frog appliances were designed to simulate maxillary molar distalization: tooth-button-borne (Type A), bone-borne (Type B), bone-button-borne (Type C), and tooth-bone-borne (Type D) frog appliances. A force of 10 N was applied simulating a screw in the anteroposterior direction. To assess the von Mises stress distribution and the resultant displacements in the teeth and periodontal tissues, geometric nonlinear theory was utilized.

Results: Compared to the conventional tooth-borne frog appliance (Type A), the bone-borne frog appliances showed increased first molar distalization with enhanced mesiolingual rotation and distal tipping, but the labial inclination and intrusion of the incisors were insignificant. When replacing the palatal acrylic button with miniscrews (Types B and D), more anchorage forces were transmitted from the first premolar to palatine bone, which was further dispersed by the assistance of a palatal acrylic button (Type C).

Conclusions: Compared to tooth-borne frog appliances, the bone-borne variants demonstrated a clear advantage for en masse molar distalization. The combined anchorage system utilizing palatal acrylic buttons and miniscrews (Type C) offers the most efficient stress distribution, minimizing force concentration on the palatine bone.

Purpose: This in vitro study aimed to compare the shear bond strength (SBS) and Adhesive Remnant Index (ARI) scores of two-step orthodontic bonding systems: self-etching primer (SEP) and a self-adhesive composite. Both systems were compared to a control group with a conventional three-step adhesive.

Methods: A total of 72 extracted maxillary and mandibular premolars were randomly divided into four groups (n = 18): group 1(XT), the control group, used Transbond™ XT (conventional adhesive; 3M Unitek, Monrovia, CA, USA); group 2 (GC) used GC Ortho Connect™ (self-adhesive composite; GC Orthodontics Inc., Tokyo, Japan); group 3 (GCP) used GC primer with GC Ortho Connect™; and group 4 (SEP) used Transbond™ Plus Self-Etching Primer with Transbond™ XT. Teeth were stored in water at 37 °C for 24 h prior to SBS testing using an Instron 5543 device (Instron, Norwood, MA, USA), and ARI scores were assessed under a stereomicroscope. Data were analyzed using analysis of variance (ANOVA) and nonparametric tests.

Results: In total, 60 samples were analyzed. The GCP group exhibited the highest SBS (8.35 MPa ± 1.99), significantly higher than the XT (4.99 MPa ± 1.32, p < 0.001) and SEP (5.69 MPa ± 2.10, p = 0.001) groups. The GC group (7.50 MPa ± 1.92) also showed higher SBS than XT (p = 0.003) and the SEP group (p = 0.048). ARI scores showed no significant difference between groups overall (p = 0.303), but the GCP group had significantly higher ARI scores than the SEP group (p = 0.023).

Conclusion: GC Ortho Connect™ with or without primer demonstrated superior bond strength compared to conventional and self-etching systems, making it a viable alternative for clinical use. Further in vivo studies are needed to confirm these findings.

Purpose: This study aimed to evaluate the accuracy of different mixed dentition analysis methods in predicting the mesiodistal diameters (MDD) of unerupted permanent canines and premolars (PCP) in a Turkish population and to determine the most reliable method for clinical application.

Methods: This research represents a retrospective, population-based cross-sectional study. Seven commonly used maxilla (Mx) and mandible (Md) unerupted PCP mesiodistal diameter prediction methods (Tanaka-Johnston, Moyers, Tränkmann, Legovic, Gross-Hasund, Bachmann, and Melgaço methods) were compared. The study included 120 Turkish children (60 males, 60 females) aged 13-16 years. MDD was measured using digital dental models. The predicted values were analyzed for accuracy by comparing them with the actual tooth diameters. Statistical analyses assessed the differences between the methods and their reliability in male and female subjects.

Results: For the investigated Turkish population, the Gross-Hasund (Mx female: 0.32 ± 1.07 mm; Mx male: 0.22 ± 0.79 mm; Md female: 0.29 ± 0.79 mm; Md male: 0.55 ± 0.80 mm) and Bachmann methods (Mx female: 0.26 ± 1.04; Mx male: 0.24 ± 0.82 mm; Md female: 0.17 ± 0.72 mm; Md male: 0.52 ± 0.83 mm) provided the most accurate predictions, with minimal deviation from actual tooth sizes. The Tanaka-Johnston and Moyers methods tended to overestimate tooth sizes in males and underestimate them in females. The Tränkmann method showed the highest prediction error, particularly in males (Mx: 2.98 ± 1.40 mm; Md: 3.05 ± 0.78 mm). Sex differences were statistically significant in most methods, highlighting the necessity for population- and sex-specific adjustments in mixed dentition analyses.

Conclusion: The findings suggest that currently available prediction methods may not fully apply to the Turkish population without modifications. The Gross-Hasund and Bachmann methods were the most dependable, whereas the Tränkmann method showed significant discrepancies. Developing population-specific regression equations may improve the accuracy of mixed dentition analysis and enhance orthodontic treatment planning in Turkish individuals.

Purpose: This study aimed to compare the accuracy of orthodontic tooth movements achieved with three-dimensionally (3D) printed aligners (Noxi, Sweden&Martina, Due Carrare, Padova, Italy) using a 12 h/day protocol with that of thermoformed aligners (F22 aligner, Sweden&Martina, Due Carrare, Padova, Italy) using a 22 h/day protocol.

Methods: Of the 40 white adult patients (12 men and 28 women, mean age 30.1 years) undergoing orthodontic treatment with aligners selected based on specific inclusion criteria, 20 patients were treated with Noxi aligners using a 12 h/day protocol (study group), and the remaining 20 patients were treated with F22 aligners using a 22 h/day protocol (control group). Pretreatment, ideal posttreatment (as planned in the setup), and real posttreatment digital models were analyzed using VAM software (Vectra, Canfield Scientific, Fairfield, NJ, USA). Angular and linear measurements were evaluated to measure mesiodistal tipping, vestibulolingual tipping, and rotational movements for 1120 teeth. Data were compared to evaluate treatment accuracy for each tooth, with statistical analysis of the results.

Results: No statistically significant differences in accuracy emerged between the study group (64.2%) and the control group (65.4%) for any type of tooth movement or tooth category. In the study group, vestibulolingual tipping showed the highest predictability (69.63%), followed by mesiodistal tipping (65.38%) and rotation (60.5%). In the control group, the vestibulolingual and mesiodistal movements showed the highest predictability, with a mean accuracy of about 67%, followed by rotation (62.3%).

Conclusion: Despite the reduced collaboration request, the group treated with Noxi aligners did not show any significant differences compared to the group treated with F22 aligners with regard to percentage accuracy for all analyzed orthodontic movements.

Purpose: The indication for orthodontic treatment in children and adolescents is based on severity of tooth and jaw malocclusions that lead to limitations in oral health-related quality of life (QoL). We have already shown how overbite and overjet deviations negatively affect QoL. However, few studies have investigated the influence of anterior crowding in the upper jaw on QoL.

Methods: We selected 734 children and adolescents aged 11-14 years from a population-based longitudinal cohort study (LIFE Child). The data used in this study were retrospectively analyzed. Evaluable jaw models were available for 554 subjects in which we performed three orthodontic space analyses: (i) purely visual assessment of the crowding of the incisors in the upper jaw (VA), (ii) the Little index (LI), and (iii) the Lundström analysis (LA). Limitations in QoL were determined using the German version of the Child Perceptions Questionnaire (CPQ-G-11-14), taking into account the effects of age, gender, socioeconomic status (Winkler score), orthodontic treatment, oral hygiene, overbite/overjet, and dental caries (decayed, missing, filled teeth [DMFT] index) as possible influencing factors.

Results: The percentage of individuals with crowding in our cohort was 11% according to VA, 14.3% according to LI, and 7.3% according to the LA. Within the three analyses, the groups of individuals with crowding did not fully overlap. The CPQ score (subscales: "emotional and social well-being") was significantly higher in subjects with crowding independent of the type of crowding analysis (p < 0.05), gender, or socioeconomic status (multivariable linear regression analysis).

Conclusion: Children and adolescents with crowding had significantly more QoL impairments, especially related to emotional and social well-being. It is necessary to perform more than one crowding analysis in order to find more affected individuals with a reduced QoL due to crowding.

Purpose: The effects of caffeine on bone metabolism and orthodontic tooth movement are largely inconsistence. This study investigated the dual effect of caffeine on receptor activator of nuclear factor κΒ ligand (RANKL)-induced osteoclastogenesis in RAW 264.7 cells and the role of adenosine receptors in these effects.

Methods: RAW 264.7 cells were treated with RANKL with or without 1-300 μM of caffeine. Cell viability and the numbers of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells were evaluated. The effect of caffeine on osteoclast activity was validated by bone resorption assays to measure the release of a fluorescent probe, resorption pit areas, and visualization by scanning electron microscope (SEM). The role of adenosine receptor (AR) subtypes in caffeine-, inducing or -inhibiting osteoclast differentiation were analyzed using AR antagonists.

Results: Caffeine at concentrations 1-100 μM did not affect cell viability. The number of TRAP positive cells, which represent osteoclast differentiation, increased with RANKL treatment and further increased with low concentrations of caffeine (1-10 µM). However, higher concentrations (30-300 µM) inhibited RANKL-induced TRAP formation. Similarly, the release of fluorescent probes and the formation of resorption pit areas, which represented osteoclast activity, increased at low concentrations and were reduced at high concentrations of caffeine. SEM micrographs demonstrated a pattern similar to the pit assay. In addition, the A_2AR antagonist tended to increase osteoclast differentiation, while the A₁R antagonist inhibited the caffeine effect.

Conclusion: Caffeine has a dual effect depending on the concentration. At low concentrations, caffeine enhanced osteoclast differentiation and activity, while higher concentrations diminished osteoclastogenesis. The A₁R receptor may be responsible for caffeine-induced osteoclast differentiation.

Objective: To comparatively evaluate the in vitro cytotoxicity of three commercially available silver solder materials in different forms-traditional silver solder with flux, silver solder incorporated with flux, and silver solder paste with flux-on Balb/c 3T3 fibroblast cell lines.

Materials and methods: Ninety-six samples were categorized into four groups: group 1 (only cell culture medium), group 2 (silver solder + flux), group 3 (universal silver solder), and group 4 (silver solder paste with flux). Each group had 24 samples assessed at three intervals: 24 h (T1), 7 days (T2), and 30 days (T3). Cytotoxicity was evaluated using the neutral red uptake assay, measuring optical density at 540 nm. Data were analyzed using one-way analysis of variance (ANOVA), Tukey's post hoc test, and paired t‑tests (p < 0.05).

Results: All test groups exhibited increased cytotoxicity over time, with the highest toxicity observed at 24 h. Group 4 (solder paste with flux) showed the greatest cytotoxicity (96.75% nonviable cells), followed by group 2 (76.13%) and group 3 (71.83%). The control group showed minimal change (16.4%). ANOVA revealed significant differences between groups at all-time points (p < 0.001). Post hoc analysis confirmed that the solder paste group was significantly more cytotoxic than the others. Time-dependent reductions in cell viability were observed, particularly between T2 and T3.

Conclusion: All tested silver solder materials demonstrated cytotoxic effects on Balb/c 3T3 fibroblasts. The silver solder and flux displayed the lowest cytotoxicity, followed by universal silver solder, and silver solder paste with flux demonstrating the highest cytotoxicity. These findings highlight the need for careful material selection in orthodontic appliance fabrication to minimize adverse biological effects.

Purpose: The aim of this study was to investigate the difference in enamel loss, composite residue, and time during removal of fixed orthodontic retainers using ultraviolet (UV) light compared to standard white light.

Methods: A nickel-chromium retainer was bonded to 4 bovine teeth using a fluorescence-modified composite (Aligner Flow Composite, Voco, Cuxhaven, Germany); 20 models were created. In a split-mouth design, 2 teeth per retainer were removed using standard white light (non-FIT) and 2 teeth using the fluorescence-aided identification technique (FIT) with UV light. Removal time was recorded for each tooth. Intraoral and optical coherence tomography (OCT) scans were taken of the tooth before bonding (T0) and after retainer removal (T1). The intraoral scans were analyzed using the software Avizo to quantify enamel loss (T0-T1) and composite residue (T1-T0). The OCT scans were evaluated using a dichotomous scoring system for enamel loss and a four-point scoring system for composite residue.

Results: There was no significant difference in removal time for the two groups. The overlay of intraoral scans showed significantly less enamel loss in area (39.35 ± 39.98 mm² vs. 65.44 ± 58.11 mm², p = 0.0235) and volume (3.41 ± 6.15 mm³ vs. 8.86 ± 11.65 mm³, p = 0.0116), as well as less composite residue in area (8.22 ± 16.04 mm² vs. 30.87 ± 49.65 mm², p = 0.0083) and volume (0.41 ± 0.87 mm³ vs. 2.34 ± 3.94 mm³, p = 0.0037) in the FIT group compared to standard white light. While OCT scans showed no significant difference in enamel loss, it proved that the amount of composite residue was significantly less in the FIT group compared to the standard light controls (5.88 ± 10.54 vs. 22.66 p = 0.0072).

Conclusion: Although the FIT method does not reduce the removal time of orthodontic fixed retainers, it has been shown to be beneficial in preserving enamel and leaving less composite residue.