Tooth Movement Research Articles

Minimally invasive prosthodontics using the concept of prosthetically guided orthodontics.

This case report aims to present how digital technology can be employed to plan the orthodontic movement of teeth into their final positions for prosthodontic rehabilitation. An interdisciplinary approach to treatment planning and the result of prosthodontic treatment involves the cooperation of an orthodontist and a prosthodontist. When planned to achieve optimal results for a minimally invasive and functional prosthodontic treatment, orthodontic pretreatment provides superior esthetic results and favorable long-term success. The orthodontic movements of the teeth were planned so that the prosthodontist could reconstruct an optimally functional and esthetic occlusion while preserving the hard dental tissues. The orthodontic pretreatment minimized the need to prepare the teeth, avoiding any mucogingival surgery to improve the gingival architecture. In complex clinical cases, it is essential to evaluate the advantages of an orthodontic pretreatment before starting a prosthodontic treatment. This pretreatment can help preserve dental tissues, reduce or eliminate the need for surgical intervention, and achieve long-term stability and esthetic results. This case clearly shows the benefits of orthodontic pretreatment for prosthodontic outcomes. With modern digital tools, such an orthodontic pretreatment should become standard clinical practice when planning a complex clinical case.

The effect of cacao bean extracts on the prevention of periodontal tissue breakdown in diabetic rats with orthodontic tooth movements

ObjectiveProper management of orthodontic treatment in diabetic patients is essential due to the heightened risk of periodontal tissue breakdown associated with hyperglycemia. Cacao bean extracts (CBE) are known to reduce the inflammatory response and increase synthesis and angiogenesis in periodontitis. Therefore, this study aims to examine the effect of CBE on preventing periodontal tissue breakdown in diabetes with orthodontic force. MethodsA total of 25 Wistar rats were divided randomly into 5 groups, including non-diabetes, diabetes, diabetes cacao 125, 250, and 500 mg/kg BW. Diabetic rats were induced with the stratified dose of Streptozotocin, and a 30-g-force from orthodontic device was applied in all groups. Diabetes cacao group was given CBE for 7 days using a gastric probe. GCF samples were used to analyze the eNOS level through the ELISA method. NFκB, Collagen-1, and FGF-2 expression were then assessed using the immunohistochemical method, while the number of fibroblasts and blood vessels was observed using hematoxylin-eosin stained tissue. The data obtained were analyzed with one-way ANOVA and post hoc tests, with p < 0.05. ResultsCBE at a dose of 250 mg/kg BW significantly increased eNOS level, Collagen-1, and FGF-2 expression, and the number of fibroblasts and blood vessels in diabetes groups. Meanwhile, the treatment decreased NFκB expression in diabetes groups (p < 0.05). ConclusionThis study proved that CBE increased periodontal ligament synthesis and angiogenesis and decreased inflammatory response, thereby preventing periodontal tissue breakdown in diabetic rat models with tooth movement.

Correlation of sex hormone levels with orthodontic tooth movement in the maxilla: a prospective cohort study.

Sex hormones secreted during the menstrual cycle and the application of orthodontic forces to teeth can affect the metabolism of periodontal ligaments. This study aimed to determine whether there are any differences in orthodontic tooth displacement during the menstrual cycle and when using hormonal contraceptives and whether the amount of female sex hormones influences the efficiency of tooth displacement. A total of 120 women aged between 20 and 30 years with Angle Class II requiring transpalatal arch (TPA) to derotate teeth 16 and 26 were included in this study. The participants were divided into two groups: group A, which included women with regular menstruation, and control group B, which included women taking monophasic combined oral contraceptives. Group A was divided into subgroups according to the moment of TPA activation: menstruation (A1), ovulation phase (A2), and luteal phase (A3) (examination I). On intraoral scans, measurement points were marked on the proximal mesial cusps of teeth 16 and 26, and the intermolar distance (M1) was determined. The change in the position of the measurement points 6 weeks after activation (examination II) made it possible to determine the derotating extent of teeth 16 (O16) and 26 (O26) and the widening of the intermolar distance (M2-M1). In examinations I and II, tooth mobility in the alveoli was assessed using Periotest based on the periotest values (PTV) PTV1 and PTV2, respectively. A significant difference in all parameters was observed among groups A1, A2, and A3 (P < 0.001). Group A3 showed the highest values of parameters O16, O26, and M2-M1, and group A2 showed the lowest values, which did not differ from the control group (P = 0.64). PTV2 and PTV1 were the highest in group A3 and the lowest in groups A1 and B. Intergroup differences were statistically significant (P < 0.001). With the quantification of changes in tooth mobility in the alveoli during the menstrual cycle in women undergoing orthodontic treatment, it was possible to determine that female sex hormones affect the effectiveness of orthodontic treatment, and the optimal moment for TPA activation is the luteal phase of the menstrual cycle.

Therapeutic dosage of isotretinoin in rats may influence orthodontic tooth movement

Objective Isotretinoin, also known as 13-cis-retinoic acid, is an isomer of tretinoin, the oxidized form of Vitamin A. Orthodontic tooth movement (OTM) is the result of a cascade of inflammatory responses stimulated by a physical element that is the force generated by orthodontic appliances. Isotretinoin is mainly used among adolescents and young adults, and coincidentally it is this age group that also undergoes orthodontic treatment. Materials and Methods Fifty-five animals were used, and they were randomly divided into 11 groups, containing 5 animals in each group. Group 1: Control; Group 2: OTM for 7 days; Group 3: OTM for 14 days; Group 4: Treated with isotretinoin for 14 days with a dosage of 7.5 mg/kg/day; Group 5: Treated with isotretinoin for 14 days with a dosage of 1.0 mg/kg/day; Group 6: Treated with isotretinoin for 21 days with a dosage of 7.5 mg/kg/day; Group 7: Treated with isotretinoin for 21 days with a dosage of 1.0 mg/kg/day; Group 8: Treated with isotretinoin for 14 days with a dosage of 7.5 mg/kg/day and undergoing OTM for 7 days; Group 9: Treated with isotretinoin for 14 days with a dosage of 1.0 mg/kg/day and undergoing OTM for 7 days; Group 10: Treated with isotretinoin for 21 days with a dosage of 7.5 mg/kg/day and undergoing OTM for 14 days; Group 11: Treated with isotretinoin for 21 days with a dosage of 1.0 mg/kg/day and undergoing OTM for 14 days. In Groups 8, 9, 10 and 11, the animals were treated with isotretinoin for 7 days before OTM and maintained during the movement period in the respective groups.Results There was a significant difference in microtomographic parameters, including Trabecular Volume (BV/TV), Trabecular Thickness (Tb.Th), Number of Trabeculae (Tb.N), and Trabecular Separation (Tb.Sp), between the groups. The group that received orthodontic force in conjunction with isotretinoin treatment at a dosage of 7.5 mg/kg/day exhibited lower tooth displacement over a period of 21 days and 14 days. Conclusion Isotretinoin caused a reduction in tooth displacement during OTM when administered at a dose of 7.5 mg/kg/day and isotretinoin did change the microtomographic parameters of treated animals.

Beyond the ARCH: Examining mandibular third molar movements in response to premolar and single incisor extractions in orthodontic practice

Mandibular third molars have been the interest of the orthodontic professionals, not only because of their Position Eruptive pattern, also because of their possible role in the development of late incisor crowding. The impaction rate of the third molars (mandible &amp;#62; maxilla) is high compared to any other teeth. The impaction incidence of M3s may be lower in patients with orthodontic premolar extraction due to mesial movement of the posterior teeth. In this study angular and positional changes of mandibular 3 molars will be evaluated with premolars as well as single incisor extraction.: This study includes 30 Pre-treatment and post-treatment orthopantomogram (OPG) of patients seeking orthodontic treatment with extractions of premolars, single incisor are categorized into 2 groups -Group I includes premolar extractions, Group II includes single incisor extractions.The study concluded that extracting premolars or single incisors did not result in improved mandibular M3 angulation on both left and right sides during the observation period.The insignificant change in angulation suggests that there are other factors that play a role in the process of alteration of third molar angulation

Failure rate of infra-zygomatic crest (IZC) bone screws in orthodontics: A Systematic review

The aim of this review is to provide a precise estimation of infra-zygomatic crest (IZC) bone screw failure rate during orthodontic treatment. Data were obtained using the Cochrane Central Register of Controlled Trails (central), PUBMED, EMBASE, google scholar, OVID, Wiley library till 1 January 2022. The titles and abstract of the electronic search were screened and evaluated by two observers according to the inclusion and exclusion criteria. This review was enrolled in PROSPERO (registration ID number CRD42020206610). There were 1725 records identified through electronic and 1 additional record identified through manual search. After 377 duplicate removal, 1349 studies were screened on the base of title and abstract the final sample included 9 studies that meet the primary inclusion criteria were selected. Each study was assessed using the evaluation method described in the Cochrane handbook for systematic reviews. All studier collectively included of the 1238 IZC miniscrews. Included studies ranged from 20 to 772 IZC miniscrews and the average number was approximate 137 IZC miniscrews per study. The diameter of inserted IZC miniscrews ranged from 1.2 to 2.3 mm and length ranged from 6 to 17 mm. The recorded failure rate ranged from 0% to 47.2%, and the average failure rate for IZC miniscrew was 9.45% (with 95% CI [58.91; 93.82]).IZC miniscrew has low failure rate which suggest that IZC miniscrew are clinically reliable. Miniscrew are a stable anchorage for orthodontic tooth movement and zygomatic buttress of maxilla is suitable region for skeletal anchorage device placement.

Transforming Adolescent Smiles: Correcting Skeletal Mandibular Retrusion and Bimaxillary Protrusion with Clear Aligners.

Maxillary protrusion combined with mandibular retraction is a highly prevalent but extremely complex maxillofacial deformity that can have a serious negative impact on patients' facial aesthetics and mental health. The traditional orthodontic treatment strategy often involves extracting 4 first premolars and conventional fixed techniques, combined with mini-implant screws, to retract the anterior teeth and improve facial protrusion. In recent years, an invisible orthodontic technique, without brackets, has become increasingly popular. However, while an invisible aligner has been used in some cases with reasonable results, there remain significant challenges in achieving a perfect outcome. This case report presents an adolescent patient with bimaxillary protrusion and mandibular retrognathia. Based on the characteristics of the invisible aligners and the growth characteristics of the adolescent's teeth and jawbone, we designed precise three-dimensional tooth movement and corresponding resistance/over-correction for each tooth, while utilizing the patient's jawbone growth potential to promote rapid development of the mandible, accurately and efficiently correcting bimaxillary protrusion and skeletal mandibular retrognathia. The patient's facial aesthetics, especially the lateral morphology, have been greatly improved, and various aesthetic indicators have also shown significant changes, and to the patient's great benefit, invasive mini-implant screws were not used during the treatment. This case highlights the advantages of using invisible aligners in adolescent maxillary protrusion combined with mandibular retraction patients. Furthermore, comprehensive and accurate design combined with good application of growth potential can also enable invisible orthodontic technology to achieve perfect treatment effects in tooth extractions, providing clinical guidance for orthodontists.

Root resorption in orthodontic treatment with clear aligners: A systematic review

The use of clear aligners in orthodontic treatment has grown in popularity because of its visual appeal and patient-friendly nature. In contrast to fixed appliance treatments (FAT), the relationship between external apical root resorption (ERR) and clear aligners is still unknown. The objective of this systematic review was to evaluate the frequency and severity of root resorption in clear aligner orthodontic treatment, compare it to fixed multi-bracket appliances, and determine the factors that contribute to this phenomenon. The review was conducted without regard to linguistic constraints, using PRISMA criteria and examining studies from 2000 to 2023. MEDLINE/PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials were among the databases that were searched. MeSH words about root resorption, aligners, and orthodontics were utilized. Cohort studies, case-control studies, randomized clinical trials, and comparative clinical studies assessing root resorption during clear aligner orthodontic therapy. Out of the 116 studies that were first found, 11 studies were included in the final analysis. While several trials revealed equal results or no significant differences, six reported decreased incidence and severity of ERR in clear aligner therapies (CAT) compared to FAT. A meta-analysis revealed that CAT had less severe ERRs than FAT. In both treatments, ERR frequently affected the maxillary lateral incisors. Potential significant factors included the mechanical distinctions between CAT and FAT, length of therapy, tooth movement velocity, degree of malocclusion, and extraction instances.The review indicates that there may be differences in the frequency and intensity of ERR between CAT and FAT. In multiple investigations, CAT demonstrated reduced ERR severity, although it did not completely eradicate its recurrence. Mechanical characteristics, length of therapy, degree of malocclusion, and number of extraction instances were factors affecting ERR. The included studies' quality assessment indicated a moderate to substantial risk of bias, highlighting the need for more thorough research using reliable measuring techniques, especially when utilizing CBCT imaging.

Two simple yet efficient biomechanics for correction of retroclined maxillary central incisors

Angle’s class II division 2 malocclusion is characterized by retroclined maxillary central incisors and increased overbite. The first step in the treatment of such cases involves the correction of incisor inclination and their intrusion. Conventional techniques for intrusion are taxing on the anchor teeth like molars and adjacent teeth like lateral incisors. Appropriate biomechanical use of temporary anchorage devices (TADS) will enable the clinician to avoid undesirable tooth movements. The following are two cases in which simple and efficient biomechanics have been performed with the use of TADS for the correction of incisor inclination and deep overbite. The case-specific use of single vs two mini implants as well as round vs rectangular wire for intrusion and proclination of central incisors has also been explained.

Comparison of Amount of Space Closure During En- Masse Retraction of Maxillary Anterior Teeth Using Three Accelerated Orthodontic Treatment Techniques- Micro Osteo-Perforation, Photo Bio-Modulation and Peizocision : A Retrospective Study

AIM: The study aimed at comparing the amount of space closure using peizocision (PZ) and micro- osteoperforation (MOP) and low-level laser therapy (LLLT). Materials and methods: A retrospective study consisted of 3 groups, sample number of minimum 8 patients per group were estimated using statistical model called an Analysis of Variance, or ANOVA model. Three sets of data were collected. Which included patients who were treated with upper first premolar extraction for en- masse retraction of maxillary anterior teeth using NiTi closed coil spring with regional acceleratory procedures. The data collected was divided into 3 groups, GROUP 1- micro osteo perforations (n=8), GROUP 2- photo bio modulation (n=8), GROUP 3- peizocision (n=8).sing digital Vernier calipers, a direct approach was used to measure all the stone casts obtained before canine retraction (T0) and after the retraction was completed after three months (T1). The statistical analysis was performed on the data acquired about the amount of space closure of en-masse retraction of maxillary anteriors in the PZ, LLLT, and MOP groups. Results: Compared to MOP (2.60mm) and LLLT (2.44mm), the PZ group had a greater mean amount of space closure (5.06mm). In conclusion, the quantity of space closure in piezocision was significantly higher than that in MOP and LLLT, although there was no statistically significant difference between the two. It is imperative that treatment duration be shortened. Finding the most effective and practical method to speed up tooth movement using the biomechanical mechanisms that are currently in place is therefore necessary

Comparison of treatment effects between clear aligners and fixed appliances in patients treated with miniscrew-assisted molar distalization.

The biomechanics in achieving molar distalization may differ between fixed appliances and clear aligners in the control of tooth movement. The objective of this study was to compare the treatment effects between clear aligners (CA) and fixed appliances (FA) in patients treated with miniscrew-assisted molar distalization. The sample consisted of 46 subjects with mild-to-moderate crowding. A total of 22 patients treated with clear aligners (age, 25.66 ± 6.11 years old) and 24 patients treated with fixed appliances (age, 24.04 ± 4.95 years old) for miniscrew-assisted molar distalization were included in this study. The dental and skeletal changes were evaluated by the pre- and post-treatment lateral cephalograms. Significant changes were found with the vertical variables SN-OP angle (2.24 ± 3.22°, P < .05) and SN-MP angle (0.73 ± 1.15°, P < .05) for the FA group when compared with the CA group (SN-OP angle 0.41 ± 2.26° and SN-MP angle -0.21 ± 1.38°, P > .05). Both treatment groups achieved a 2-3mm. molar distalization with significant intrusion of the upper molars. The CA group showed significantly less distal tipping of molars (U6^PP angle -2.29 ± 3.29° and L6^MP angle -2.92 ± 2.49°, P < .05) compared to the FA group (-5.24 ± 4.28° and -5.53 ± 5.03°, P < .05). In addition, significant retraction and lingual inclination of the upper and lower incisors were found in both groups. The changes of tooth position were evaluated by 2D lateral cephalograms, not 3D measurements. Compared to fixed appliances, clear aligners seemed to have better control of vertical dimension and distal tipping of molars in patients treated with miniscrew-assisted molar distalization.

The effect of orthodontic Force Application and Tooth Movement on Dental Pulp

This systematic review aimed to conclusively investigate the effect of continuous intrusive force application on human pulpal blood flow (PBF). It is a well-established fact that applying a severe orthodontic force for an extended period can cause irreversible pulpitis and necrosis in the pulp by accelerating the inflammation process. In contrast, utilizing moderate and intermittent forces allows for ample tooth movement, limits pulp damage, and facilitates pulp healing. Materials and methods: A comprehensive search of published studies was conducted in several electronic databases such as MEDLINE, PubMed, EMBASE, Scopus, Web of Science, CINAHL, and the Cochrane Database of Systematic Reviews, as well as Google Scholar. The search was conducted without limitations to find published studies. The results showed that orthodontic forces can lead to a decrease in pulpal blood flow, which causes a reduction in tooth sensitivity. This reduction is indicated by an increase in response thresholds and more negative responses to tooth sensitivity tests. Conclusion: applying a severe orthodontic force over a prolonged period of time can lead to irreversible pulpitis and necrosis in the pulp due to an increase in the inflammation process. However, using moderate and intermittent forces can facilitate sufficient tooth movement while minimizing damage to the pulp. This highlights the importance of the endodontic-orthodontic interface and the need to consider dental pulp health during orthodontic treatment to avoid dental trauma.

NF-κB Decoy Oligodeoxynucleotide-Loaded Poly Lactic-co-glycolic Acid Nanospheres Facilitate Socket Healing in Orthodontic Tooth Movement.

Orthodontic space closure following tooth extraction is often hindered by alveolar bone deficiency. This study investigates the therapeutic use of nuclear factor-kappa B (NF-κB) decoy oligodeoxynucleotides loaded with polylactic-co-glycolic acid nanospheres (PLGA-NfDs) to mitigate alveolar bone loss during orthodontic tooth movement (OTM) following the bilateral extraction of maxillary first molars in a controlled experiment involving forty rats of OTM model with ethics approved. The decreased tendency of the OTM distance and inclination angle with increased bone volume and improved trabecular bone structure indicated minimized alveolar bone destruction. Reverse transcription-quantitative polymerase chain reaction and histomorphometric analysis demonstrated the suppression of inflammation and bone resorption by downregulating the expression of tartrate-resistant acid phosphatase, tumor necrosis factor-α, interleukin-1β, cathepsin K, NF-κB p65, and receptor activator of NF-κB ligand while provoking periodontal regeneration by upregulating the expression of alkaline phosphatase, transforming growth factor-β1, osteopontin, and fibroblast growth factor-2. Importantly, relative gene expression over the maxillary second molar compression side in proximity to the alveolus highlighted the pharmacological effect of intra-socket PLGA-NfD administration, as evidenced by elevated osteocalcin expression, indicative of enhanced osteocytogenesis. These findings emphasize that locally administered PLGA-NfD serves as an effective inflammatory suppressor and yields periodontal regenerative responses following tooth extraction.

Esthetic outcomes in orthodontics through digital customization with a lingual appliance system.

Contemporary fixed orthodontic appliances are shifting from non-customized pre-adjusted appliances to custom-designed and printed appliances with novel digital setup systems. We are one step closer to precision dentistry and orthodontics using personalized mechanics and custom appliances. However, despite the evidential enhancement and other improvements to fixed appliances, tooth movement is still limited to five degrees of freedom. Opening or closing spaces still requires manually placing elastomeric chains or coil springs. In this article, we aimed to demonstrate how advancements in CAD/CAM technology, reverse engineering, and digital customization are helping orthodontics constantly evolve, enabling treatment with enhanced esthetics and minimal compliance. The clinical system (InBrace®, Irvine, CA) described in this article uses a patient-specific, digitally designed multiloop NITI wire that delivers friction-free, light, and continuous forces and activates automatically whenever the malocclusion deviates from the digital setup. Through digital customization, InBrace allows for automated tooth movement in all six degrees of freedom, including space opening or closure, via programmed non-sliding mechanics. Precision orthodontics and personalized treatment have been significant developments in orthodontics recently. This article focuses on how a technologically advanced lingual appliance system could achieve targeted cosmetic results methodically via automation and personalization.

Small nucleolar RNA host gene 5 plays a role in orthodontic tooth movement by inhibiting osteoclast differentiation.

The alveolar bone remodelling promoted by reasonable mechanical force triggers orthodontic tooth movement (OTM). The generation of osteoclasts is essential in this process. However, the mechanism of mechanical force mediating osteoclast differentiation remains elusive. Small nucleolar RNA host gene 5 (SNHG5), which was reported to mediate the osteogenic differentiation of bone marrow mesenchymal stem cells in our previous study, was downregulated in human periodontal ligament cells (hPDLCs) under mechanical force. At the same time, the RANKL/OPG ratio increased. Based on this, we probed into the role of SNHG5 in osteoclast formation during OTM and the relevant mechanism. SNHG5 and the RANKL/OPG ratio under different compressive forces were detected by western blotting (WB) and qRT-PCR. Impact of overexpression or knockdown of SNHG5 on osteoclast differentiation was detected by qRT-PCR, WB and transwell experiments. The combination of SNHG5 and C/EBPβ was verified by RNA immunoprecipitation and RNA pull-down assays. The expression of SNHG5 and osteoclast markers in gingiva were analysed by qRT-PCR and the paraffin sections of periodontal tissues were used for histological analysis. Compressive force downregulated SNHG5 and upregulated the RANKL/OPG ratio in hPDLCs. Overexpression of SNHG5 inhibited RANKL's expression and osteoclast differentiation. SNHG5 combined with C/EBPβ, a regulator of osteoclast. The expression of SNHG5 in periodontal tissue decreased during OTM. SNHG5 inhibited osteoclast differentiation during OTM, achieved by affecting RANKL secretion, which may provide a new idea to interfere with bone resorption during orthodontic treatment.

Increased TGF-β1 level after cocoa administration during orthodontics tooth movement in Cavia cobaya

Background: Orthodontic tooth movement (OTM) is a process of tooth movement in the alveolar socket through a bone remodeling process. Cocoa contains caffeine as a bioactive component. The number of studies on the effects of caffeine on orthodontic tooth movement is rising. Purpose: This study aimed to determine the effect of caffeine in cocoa administration on TGF-β1 levels in the pressure side during orthodontic tooth movement. Methods: Twelve Cavia cobaya were divided into 4 groups: control group (ONC), treatment group with 2.3 mg caffeine in cocoa (OWC1), 3.45 mg dose (OWC2) and 4.6 mg dose (OWC3) (n=3). A NiTi open coil spring with light force was applied to two lower incisors tooth of Cavia cobaya. TGF-β1 level in GCF of the pressure side was analyzed using ELISA on days 0, 1, 7, and 14. Data were analyzed using the Two-way ANOVA test (p&lt;0.05) and the LSD Post-Hoc test. Results: Research indicated improvement of TGF-β1 level from the control group with the least average followed group caffeine in cocoa 2.3 mg (OWC1), 3.45 mg (OWC2), and 4.6 mg (OWC3) (p&lt;0.05). Conclusion: This study confirmed that caffeine in cocoa administration increase TGF-β1 level during orthodontics tooth movement on Cavia cobaya in the pressure side.

Change in the Spatial Position of Mini-implants During Distal Movement of the Entire Maxillary Dentition: An Observational CBCT Study.

To determine the change in the sagittal and vertical position of mini-implants placed in the maxilla during distal movement of the entire maxillary dentition. Overall, 28 mini-implants (1 placed on each side in 14 patients) were evaluated in healthy patients aged 15 to 25 years old. CBCTs were taken immediately after leveling and aligning prior to distalization (T1) and after 6 months (T2) to evaluate the distal movement of the maxillary teeth and position of the mini-implants. The vertical and sagittal angulation of each mini-implant was measured at T1 and T2. The linear distance between the mini-implant and the alveolar crest, the maxillary sinus, the maxillary second premolar, and the maxillary first permanent molar were measured. The change in angulation and the linear displacement of the miniimplant were evaluated in the vertical and sagittal plane. Wilcoxon signed rank test was performed to determine if there was a statistically significant change in the position of the mini-implant. Vertically, there was a significant change in the linear distance between the mini-implant and the alveolar crest on the right side (P ≤ .006) as well as the miniimplant and the maxillary sinus on the left side (P ≤ .003). Sagittally, there was a statistically significant rotation of the miniimplant occlusally (left side P ≤ .004 and right side P ≤ .002). The head and tip of the mini-implant were displaced toward the maxillary second premolar and away from the maxillary first permanent molar, respectively. There was a significant relative displacement of the mini-implant anteriorly away from the maxillary first permanent molar (left side P ≤ .026 and right side P ≤ .041) and closer to the maxillary second premolar (left side: P ≤ .011 and right side: P ≤ .002). There was a statistically and clinically significant rotation of the mini-implant in the vertical and sagittal direction during distal movement of the entire maxillary arch. The linear displacement of the mini-implant was more pronounced in the sagittal direction than the vertical direction.

Inhibition of 12/15-lipoxygenase reduces orthodontically induced root resorption in rats.

To investigate whether the inhibition of 12/15-lipoxygenase (12/15-LOX), one of the core enzymes of the arachidonic acid cascade, suppresses orthodontically induced root resorption (OIRR), and examine the involvement of the hyaline degeneration of periodontal ligament cells and odontoclast differentiation. The left maxillary first molars of 10-week-old male Wistar rats were moved mesially for 14 days using a closed-coil spring (25 cN) inserted between the first molar and incisor. The rats were intraperitoneally administered with a 12/15-LOX specific inhibitor (ML-351; 0.05 mmol/kg) daily in the experimental group or vehicle (dimethyl sulfoxide) in the control group. Tooth movement was measured using microcomputed tomography on day 14. The appearance of OIRR, hyaline degeneration, osteoclasts, and odontoclasts was evaluated via histological analysis. Immunohistochemical staining for receptor-activated NF-kB ligand (RANKL) and osteoprotegerin was performed. OIRR observed on day 14 in the control group was strongly suppressed by ML-351 treatment. Hyaline degeneration observed on the compression side on day 3 and the appearance of osteoclasts and odontoclasts on days 3 and 14 were significantly suppressed by ML-351. RANKL expression on day 3 was significantly suppressed by ML-351. These key processes in OIRR were substantially suppressed by ML-351 treatment. Inhibition of 12/15-LOX reduced OIRR by suppressing hyaline degeneration and subsequent odontoclast differentiation.

Creative biomechanics for complex cases

Orthodontic biomechanics play a crucial role in achieving successful outcomes, especially in complex cases requiring precise control of tooth movements. This article explores force system analysis based on the moments and forces around the center of resistance and emphasizes traditional and contemporary approaches in orthodontic biomechanics, focusing on key tooth movements such as bite opening, space closure, retraction, protraction, intrusion, and extrusion.In complex borderline cases involving nonsurgical treatment, this article addresses the significance of total arch distalization for maximum retraction, total arch intrusion for vertical control, total arch extrusion for enhancing maxillary incisor display, lever arm mechanics for achieving incisor torque control, and total arch protraction for improving the maxillary incisor show.Patient-specific factors, efficient biomechanics, and a comprehensive understanding of the limitations of treatment modalities are emphasized in pursuit of optimal orthodontic outcomes.

Inadvertent Tooth Movement from a Bonded Mandibular Lingual Retainer—A Case Report with a Follow-Up 3D Analysis of Tooth Movement and a Microscopic Evaluation of the Wire

Background: One of the rarest complications of fixed orthodontic retention is inadvertent tooth movement of the teeth bonded to the retainer. A 25-year-old patient presented at the orthodontist as she was preoccupied about the position of the lower teeth. The aim of this case report was to present a follow-up of anterior teeth alignment after fixed retainer removal and to analyze the structure of the removed fixed orthodontic retainer in a patient suffering from a twist effect. Materials and Methods: The retainer that caused inadvertent movement has been removed, and subsequent teeth displacement was assessed with scan superimposition. The retainer structure and diameter were analyzed with a laser confocal microscope. Results: The superimposition showed significant improvements in the position of the teeth. The sole removal of the activated retainer resulted in a partial self-correction of the twist effect. Under microscopic observation, changes in the dimensions of the wire were found but were too small to cause significant changes in tooth position. Conclusions: A fixed retainer should always be removed when a twist effect is diagnosed. The wire sections covered with composite are less likely to untwist. In the presented case, the changes in the dimensions of the round retainer wire could not have led to changes in the teeth’s positions.