Abstract : Objective: To measure and compare the extent of root resorption in the maxillary incisors following microimplant-assisted rapid palatal expansion (MARPE) and to identify risk factors of root resorption after expansion. Methods: Cone-beam computed tomography images were obtained from a total of 60 patients both before expansion (T1) and 3 to 6 months after expansion (T2). Measurements taken included tooth length, root length, crown length and center of resistance. Resorption length (RL) and resorption length percentage (RLp), resorption volume (RV) and resorption volume percentage (RVp) and the amount of expansion were calculated. Results: A significant difference in tooth length and volume was observed in both the central and lateral incisors before and after expansion. The resorption index (RL, RLp, RV, RVp) was significantly higher in the central incisors than in the lateral incisor. There was a significant correlation between several factors: age and RLp of the central incisors, the amount of expansion and RVp of the central incisors, tooth length of the central incisors and RL, RLp of the central incisors, root/crown ratio of the central incisors and RL of the central incisors, as well as tooth length of the lateral incisors and the RL of the lateral incisors. Conclusions: Significant root resorption occurs in maxillary incisors following MARPE, with central incisors root resorption being significantly higher than lateral incisors. Key risk factors for root resorption after MARPE include advanced age, a larger amount of expansion, initial tooth length, and a root/crown ratio.
Abstract : Objective: This study aimed to evaluate the association between low tongue position (LTP) and the volume and dimensions of the nasopharyngeal, retropalatal, retroglossal, and hypopharyngeal segments of the upper airway. Methods: A total of 194 subjects, including 91 males and 103 females were divided into a resting tongue position (RTP) group and a LTP group according to their tongue position. Subjects in the LTP group were divided into four subgroups (Q1, Q2, Q3, and Q4) according to the intraoral space volume. The 3D slicer software was used to measure the volume and minimum and average cross-sectional areas of each group. Airway differences between the RTP and LTP groups were analyzed to explore the association between tongue position and the upper airway. Results: No significant differences were found in the airway dimensions between the RTP and LTP groups. For both retropalatal and retroglossal segments, the volume and average cross-sectional area were significantly greater in the patients with extremely low tongue position. Regression analysis showed that the retroglossal airway dimensions were positively correlated with the intraoral space volume and negatively correlated with A point-nasion-B point and palatal plane to mandibular plane. Males generally had larger retroglossal and hypopharyngeal airways than females. Conclusions: Tongue position did not significantly influence upper airway volume or dimensions, except in the extremely LTP subgroup.
Abstract : Objective: To evaluate the effects of an electric toothbrush with vibrational frequencies of 125 Hz and 150 Hz on the orthodontic tooth movement (OTM) rate and the production of prostaglandin E2 (PGE2). Methods: Out of thirty patients (aged 18–25 years; 16 females and 14 males), ten patients each formed Group A and B, who used electric toothbrushes with 125 Hz and 150 Hz vibrations, respectively. The remaining ten patients (Group C) served as the control group and did not use electric toothbrushes. The rate of OTM and levels of PGE2 using microcapillary pipettes were calculated before the start of retraction (T0), on the 30th day (T1), on the 60th day (T2), and on the 90th day (T3) from the start of retraction in all the groups. Results: There was a statistically significant difference in the mean OTM values and PGE2 levels in all three groups at different time intervals, with the maximum difference seen in Group B compared to Group A and least in Group C at T1, T2 and T3. Conclusions: The rate of OTM and levels of PGE2 were highest in patients who used an electric toothbrush with 150 Hz mechanical vibration compared to those who used an electric toothbrush with 125 Hz mechanical vibration and least in patients who did not use an electric toothbrush. Mechanical vibration led to an increase in the PGE2 levels and accelerated the OTM.
Abstract : Objective: External apical root resorption (EARR) is characterized by permanent loss of dental structure at the root apex. This study aimed to systematically review gene polymorphisms associated with EARR in orthodontic patients. Methods: Electronic database searches were performed across several databases. Results: This systematic review included 21 studies. Outcome measures were based on tooth dimensions observed on radiographs obtained before and after treatment. Polymorphisms in the following genes were genotyped using polymerase chain reaction-restriction fragment length polymorphism analysis: purinergic-receptor-P2X, ligand-gated ion channel 7 (P2RX7), caspase-1/interleukin-converting enzyme (CASP1/ICE), caspase-5 (CASP5), IL-1beta (IL1B), IL-1alpha (IL1A), interleukin-1 receptor antagonist gene (IL1RN), tissue non-specific alkaline phosphatase (TNSALP), tumor necrosis factor-alpha (TNFα), tumor necrosis factor receptor superfamily gene member 11a (TNFRSF11A), secreted phosphoprotein 1 (SPP1), tumor necrosis factor receptor superfamily gene member 11b (TNFRSF11B), interleukin 17A (IL17), interleukin 6 (IL6), receptor activator of nuclear factor-kappa B (RANK), osteoprotegerin (OPG), stromal antigen 2 (STAG2), vitamin D receptor (VDR), cytochrome P450 family 24 subfamily A member 1 (CYP24A1), cytochrome P450 family 27 subfamily B (CYP27B1), group-specific component (GC), and interleukin-1 receptor-associated kinases 1 (IRAK1). Conclusions: Almost all studies suggested that IL1 gene is associated with EARR. Additionally, P2RX7 may be an important factor contributing to the etiopathogenesis of EARR. TNFRSF11A, SPP1, IL1RN, IL6, TNFRSF11B, STAG2, VDR, IRAK1, IL-17, CASP1/ICE and CASP5 have been identified in isolated studies. Further observational studies are needed to better explain the association between these genes and EARR.
Abstract : Objective: To determine the correlation between dentoskeletal parameters related to craniofacial morphology and the upper airway (UA) volume. Methods: Cone-beam computed tomography images of 106 randomly selected orthodontic patients were analyzed using NemoFab Ortho software. The dentoskeletal variables assessed were anterior facial height (AFH), posterior facial height (PFH), PFH/AFH ratio, hyoid position, maxillary width (MW), and palatal depth. The UA volume (evaluation in anatomical regions and as a whole) was also assessed using the same software. We also evaluated potential differences in UA variables between age and sex groups. The correlation between the dentoskeletal parameters and UA volume was calculated using the Pearson correlation coefficient (R). Analysis of variance and Student’s t test were performed to assess differences between age and sex for UA variables. Statistical analyses were performed using SPSS software (version 26 for Windows). Results: This study found that PFH, AFH, and MW were the dentoskeletal parameters most strongly correlated with UA volume. However, the ANB angle did not show any significant correlation with UA volume. Additionally, differences in UA volumes were observed between age groups. Sex differences were found in both the “8–12” and “≥ 16” age groups for oropharyngeal and pharyngeal volumes. Conclusions: In conclusion, our findings indicate a significant correlation between UA volume and dentoskeletal parameters, particularly those related to facial height and MW.
Abstract : Objective: To assess the color stability and translucency of full cubic stabilized zirconia (FSZ) following orthodontic bonding with different surface treatments and coffee thermocycling (CTC). Methods: This in vitro study was conducted on 120 disc-shaped specimens of FSZ. Thirty specimens were selected as the control group and remained intact. The remaining specimens were randomly divided into three groups based on the type of surface treatment (n = 30): airborne particle abrasion (APA), silica-coating (CoJet), and carbon dioxide (CO2) laser. After metal bracket bonding in the test groups, debonding and polishing were performed. Subsequently, all specimens underwent CTC (10,000 cycles). Color parameters, color difference (ΔE00), and translucency parameter (TP) were measured three times at baseline (t0), after debonding and polishing (t1), and after CTC (t2). Data were statistically analyzed (α = 0.05). Results: Significant difference existed among the groups regarding ΔE00t0t2 (p < 0.001). The APA group showed minimum (ΔE00 = 1.15 ± 0.53) and the control group showed maximum (ΔE00 = 0.19 ± 0.02) color stability, with no significant difference between the laser and CoJet groups (p = 0.511). The four groups were significantly different regarding ΔTPt0t2 (p < 0.001). Maximal increases in TP were noted in the CoJet (1.00 ± 0.18) and APA (1.04 ± 0.38) groups while minimal increase was recorded in the control group (0.1 ± 0.02). Conclusions: Orthodontic treatment makes zirconia restorations susceptible to discoloration and increased translucency. Nonetheless, the recorded ΔE00 and ΔTP did not exceed the acceptability threshold.
Abstract : Objective: This study aimed to evaluate the zygomaticotemporal suture (ZTS) maturation, analyze the age distribution patterns of ZTS maturation stages, and investigate the relationship between ZTS and cervical vertebral maturation (CVM). Methods: A total of 261 patients who underwent cone-beam computed tomography (112 males, mean age, 13.1 ± 3.3 years; 149 females, mean age, 13.7 ± 3.1 years) were examined to evaluate the ZTS stages. The ZTS stages were defined based on a modified method from previous studies on zygomaticomaxillary sutures. Differences between groups and correlations between indicators were analyzed using the Spearman correlation test, intraclass coefficient of correlation (ICC), one-way analysis of variance and rank sum test. Statistical significance was set at p < 0.05. The diagnostic value of CVM stages in identifying ZTS maturation stages was evaluated using positive likelihood ratios (LRs). Results: A positive relationship was found between the ZTS and CVM stage (r = 0.747, ICC = 0.621, p < 0.01) and between the ZTS stage and chronological age (r = 0.727, ICC = 0.330, p < 0.01). Positive LRs > 10 were found for several cervical stages (CSs), including CS1 and CS2 for the diagnosis of stage B, CS1 to CS3 for the diagnosis of stages B and C, and CS6 for the diagnosis of stages D and E. Conclusions: The ZTS maturation stage may be more relevant to the CVM stage than to the chronological age. The CVM stages can be good indicators for clinical decisions regarding maxillary protraction, except for CS4 and CS5.
Abstract : Objective: Miniscrew-assisted maxillary expansion devices are frequently used for patients with calcified midpalatal sutures. This study aimed to evaluate the effects of two bone-borne maxillary expansion appliances on the cranial and circummaxillary sutures by comparing cone-beam computed tomography (CBCT) images before and after transverse maxillary expansion. Methods: A total of 81 patients (women = 58, men = 23) were treated with either a C-expander (n = 44) or an ATOZ expander (n = 37). CBCT images were obtained before (T0) and after (T1) maxillary expansion, and the widths of 10 circummaxillary sutures were measured in the sagittal, coronal, and axial planes. The Wilcoxon signed-rank test was used to compare the changes in suture width between the C-expander and ATOZ groups, and statistical significance was set at P < 0.05. Results: The frontonasal, frontomaxillary, pterygomaxillary, nasomaxillary, internasal, intermaxillary, and midpalatal suture widths increased significantly after maxillary expansion in both the ATOZ and C-expander groups (both P < 0.05). The frontozygomatic, zygomaticomaxillary, and temporozygomatic suture widths decreased in the C-expander group (P < 0.05), whereas the frontozygomatic suture width increased significantly in the ATOZ group (P < 0.05). The width changes of the frontozygomatic, zygomaticomaxillary, temporozygomatic, pterygomaxillary, internasal, intermaxillary, and midpalatal sutures differed significantly between the two groups (P < 0.05). Conclusions: Both the C- and ATOZ expanders affected the suture width in the naso-maxillo-zygomatic region. The C-expander decreased the circum-zygomatic suture widths, whereas the ATOZ expander widened the frontozygomatic suture with no effect on other circummaxillary sutures.