Tracking orthodontic tooth movement and associated biomechanics using an integrated clinical and in vitro mechanical approach

To determine minimal dose levels required for local inhibition of orthodontic relapse by recombinant OPG protein (OPG-Fc), while also determining effects of injected OPG-Fc on alveolar bone and long bone. The Department of Orthodontics and Pediatric Dentistry at the University of Michigan. Eighteen male Sprague Dawley rats. Maxillary molars were moved with nickel-titanium springs and then allowed to relapse in Sprague Dawley rats. Upon appliance removal, animals were injected with a single dose of 1.0 mg/kg OPG-Fc, 0.1 mg/kg OPG-Fc, or phosphate-buffered saline (vehicle) just distal to the molar teeth. Tooth movement measurements were made from stone casts, which were scanned and digitally measured. Alveolar tissues were examined by histology. Micro-computed tomography was used to quantify changes in alveolar and femur bone. Local injection of OPG-Fc inhibited molar but not incisor relapse, when compared to vehicle-injected animals. No significant differences in alveolar or femur bone were seen between the three treatment groups after 24 days of relapse. Our results demonstrate that a single local injection of OPG-Fc effectively inhibits orthodontic relapse, with minimal systemic bone metabolic effects. Our results also show that a single injection of OPG-Fc will influence tooth movement only in teeth close to the injection site. These findings indicate that OPG-Fc has potential as a safe and effective pharmacological means to locally control osteoclasts, for uses such as maintaining anchorage during orthodontic tooth movement and preventing orthodontic relapse in humans.

Corticotomy is a surgical procedure that induces injury to the cortical bone to accelerate tooth movement. This study aimed to increase the depth of corticotomy to the trabecular bone and to evaluate the amount and rate of tooth movement and alveolar bone changes in response to various degrees of cortical and trabecular bone injury. Seventy-eight male Wistar rats were randomly divided into four groups based on procedure used: (1) baseline control group of orthodontic tooth movement (OTM) only; (2) OTM + 4 corticotomies (CO); (3) OTM + 4 osteotomies (OS); and (4) OTM + 16 CO. A closed-coil nickel–titanium spring was placed to move the maxillary first molar mesially with a 10 g force. On days 0, 7, 14, and 21, alveolar bone alteration and tooth movement were measured using microcomputed tomography. Significant tooth movement was related to the number and the depth of the perforations. The OTM + 16 CO group showed a greater amount and rate of tooth movement than the OTM + 4 CO group. When osteotomy and corticotomy were compared with the same volume of bone removed, the OTM + 4 OS group had a faster rate of tooth movement than the OTM + 16 CO group during the first week, with significantly reduced bone volume. However, no significant difference was observed in the amount of tooth movement between the OTM + 4 OS and OTM + 16 CO groups at the end of the study. Extending the depth of corticotomy to trabecular bone increased the amount of tooth movement by accelerating the induction and completion of bone remodeling, which accelerated the rate of tooth movement during the initial stage.

Orthodontic treatment can last between 2 and 3 years. These long treatment times can significantly decrease patient cooperation and yield adverse effects. This review aimed to evaluate the clinical effect of low-level laser therapy (LLLT) on the acceleration of orthodontic tooth movement. We searched the Cochrane Library, PubMed, and EMBASE and included only studies evaluating the effect of LLLT on orthodontic human tooth movement, according to inclusion criteria. We included thirteen studies (three controlled clinical trials [CCTs], five randomized clinical trials [RCTs], and five systematic reviews or meta-analyses). Six of the eight clinical trials showed a statistically significant effect on orthodontic tooth movement toward a low-level laser application. Comparison between studies is difficult because of parameter variability (anchorage, orthodontic appliances, wavelength, and other laser parameters); however, LLLT may be an interesting method to accelerate orthodontic tooth movement. The highest-level studies show that LLLT can accelerate orthodontic movements, but other research must be pursued. This review of the literature seems to suggest concentrating future research regarding the relationship between LLLT and orthodontic tooth movement on wavelengths in infrared radiation approximately 780–810 nm, with a fluence of approximately 5 J/cm2.

Periodontitis (PD) occurring during orthodontic treatment may interfere with the bone remodeling process. This study investigated the impact of PD on bone remodeling during orthodontic tooth movement (OTM) and explored the potential role of C-reactive protein (CRP) and the IL-6/JAK2/STAT3 signaling pathway in this process. Models for PD, OTM, and combined PD with OTM (PD+OTM) were created in Sprague-Dawley rats. Alveolar bone loss and activation of the CRP and IL-6/JAK2/STAT3 signaling pathway in periodontal tissues were observed at 7- and 14- days post-modeling. CRP knockout rats and local injection of the tyrosine kinase inhibitor AG490 used to downregulate the IL-6/JAK2/STAT3 pathway were applied to verify their regulatory roles in bone remodeling during OTM in the presence of PD. Alveolar bone resorption was significantly higher in the PD+OTM group than in the PD and OTM groups. Histological analysis revealed increased osteoclast accumulation and a higher RANKL/OPG ratio in the PD+OTM group, along with elevated CRP expression and activation of the IL-6/JAK2/STAT3 pathway. Both CRP knockout and AG490 treatment led to a reduction in osteoclasts and a decreased RANKL/OPG ratio in the PD+OTM model, as well as decreased expression of IL-6/JAK2/STAT3-related molecules. PD during OTM impairs bone remodeling, enhancing osteoclastic activity. CRP interactive with IL-6/JAK2/STAT3 expression in periodontal tissues during OTM, contributing to the imbalance in bone remodeling during OTM with PD. This study explored how periodontitis (PD) affects the way bone adjusts around teeth when the tooth is moving. Researchers used rats to mimic three situations: PD only, tooth movement only, and both conditions together. They found that when PD and tooth movement happened at the same time, it caused significantly more bone loss around the teeth than either condition alone. This was linked to more bone-removing cells and changes in key signaling molecules in the periodontal tissue, specifically CRP and a pathway involving IL-6, JAK2, and STAT3. Importantly, when the researchers either removed CRP or blocked the IL-6/JAK2/STAT3 pathway, they saw less bone loss and fewer bone-removing cells in the rats experiencing both PD and tooth movement. This shows that active PD disrupts healthy bone remodeling during orthodontic treatment, and that CRP and the IL-6/JAK2/STAT3 pathway play a key role in causing this extra damage. The findings highlight why treating periodontal disease is crucial before or during tooth movement treatment and point to potential targets for protecting bone health in orthodontic patients with periodontal problems.

Orthodontic tooth movement (OTM) is generated by a mechanical force that induces an aseptic inflammatory response in the periodontal tissues and a subsequent coordinated process of bone resorption and apposition. In this review, we critically summarize the current knowledge on the immune processes involved in OTM inflammation and provide a novel insight into the relationship between classical inflammation and clinical OTM phases. We found that most studies focused on the acute inflammatory process, which ignites the initial alveolar bone resorption. However, the exact mechanisms and the immune reactions involved in the following OTM phases remain obscure. Recent studies highlight the existence of a typical innate response of resident and extravasated immune cells, including granulocytes and natural killer (NK), dendritic, and γδT cells. Based on few available studies, we shed light on an active, albeit incomplete, process of resolution in the lag phase, supported by continuously elevated ratios of M1/M2 macrophage and receptor activator of nuclear factor κB ligand/osteoprotegerin ratio. This partial resolution enables tissue formation and creates the appropriate environment for a transition between the innate and adaptive arms of the immune system, essential for the tissue’s return to homeostasis. Nevertheless, as the mechanical trigger persists, the resolution turns into a low-grade chronic inflammation, which underlies the next, acceleration/linear OTM phase. In this stage, the acute inflammation dampens, and a simultaneous process of bone resorption and formation occurs, driven by B and T cells of the adaptive immune arm. Excessive orthodontic forces or tooth movement in periodontally affected inflamed tissues may hamper resolution, leading to “maladaptive homeostasis” and tissue loss due to uncoupled bone resorption and formation. The review ends with a brief description of the translational studies on OTM immunomodulation. Future studies are necessary for further uncovering cellular and molecular immune targets and developing novel strategies for controlling OTM by local and sustained tuning of the inflammatory process.

Effects of human relaxin on orthodontic tooth movement and periodontal ligaments in rats

To examine the mechanical properties and the usefulness of titanium-niobium-aluminum (Ti-Nb-Al) wire in orthodontic tooth movement as compared with nickel-titanium (Ni-Ti) wire. The load deflection of expansion springs was gauged with an original jig. The gradient of the superelastic region was measured during the unloading process. Expansion springs comprising the two types of alloy wires were applied to upper first molars of rats. The distance between the first molars was measured with micrometer calipers. The force magnitude of the Ti-Nb-Al expansion spring was lower than that of the Ni-Ti expansion spring over the entire deflection range. The initial force magnitude and the gradient in the superelastic region of the Ti-Nb-Al expansion springs were half those of the Ni-Ti expansion springs. Thus, Ti-Nb-Al expansion springs generated lighter and more continuous force. Tooth movement in the Ni-Ti group proceeded in a stepwise fashion. On the other hand, tooth movement in the Ti-Nb-Al group showed relatively smooth and continuous progression. At 17 days after insertion of expansion springs, there were no significant differences between the Ti-Nb-Al and Ni-Ti groups in the amount of tooth movement. These results indicate that Ti-Nb-Al wire has excellent mechanical properties for smooth, continuous tooth movement and suggest that Ti-Nb-Al wire may be used as a practical nickel-free shape memory and superelastic alloy wire for orthodontic treatment as a substitute for Ni-Ti wire.

Impact of bisphosphonate drug burden in alveolar bone during orthodontic tooth movement in a rat model: A pilot study

Literature review There is a paucity of information on the concise relationship between endodontics and orthodontics during treatment planning decisions. This relationship ranges from effects on the pulp from orthodontic treatment and the potential for resorption during tooth movement, to the clinical management of teeth requiring integrated endodontic and orthodontic treatment. This paper reviews the literature based on the definition of endodontics and the scope of endodontic practice as they relate to common orthodontic-endodontic treatment planning challenges. Literature data bases were accessed with a focus on orthodontic tooth movement and its impact on the viability of the dental pulp; its impact on root resorption in teeth with vital pulps and teeth with previous root canal treatment; the ability to move orthodontically teeth that were endodontically treated versus nonendodontically treated; the role of previous tooth trauma; the ability to move teeth orthodontically that have been subjected to endodontic surgery; the role of orthodontic treatment in the provision for and prognosis of endodontic treatment; and, the integrated role of orthodontics and endodontics in treatment planning tooth retention. Orthodontic tooth movement can cause degenerative and/or inflammatory responses in the dental pulp of teeth with completed apical formation. The impact of the tooth movement on the pulp is focused primarily on the neurovascular system, in which the release of specific neurotransmitters (neuropeptides) can influence both blood flow and cellular metabolism. The responses induced in these pulps may impact on the initiation and perpetuation of apical root remodelling or resorption during tooth movement. The incidence and severity of these changes may be influenced by previous or ongoing insults to the dental pulp, such as trauma or caries. Pulps in teeth with incomplete apical foramen, whilst not immune to adverse sequelae during tooth movement, have a reduced risk for these responses. Teeth with previous root canal treatment exhibit less propensity for apical root resorption during orthodontic tooth movement. Minimal resorptive/remodelling changes occur apically in teeth that are being moved orthodontically and that are well cleaned, shaped, and three-dimensionally obturated. This outcome would depend on the absence of coronal leakage or other avenues for bacterial ingress. A traumatized tooth can be moved orthodontically with minimal risk of resorption, provided the pulp has not been severely compromised (infected or necrotic). If there is evidence of pulpal demise, appropriate endodontic management is necessary prior to orthodontic treatment. If a previously traumatized tooth exhibits resorption, there is a greater chance that orthodontic tooth movement will enhance the resorptive process. If a tooth has been severely traumatized (intrusive luxation/avulsion) there may be a greater incidence of resorption with tooth movement. This can occur with or without previous endodontic treatment. Very little is known about the ability to move successfully teeth that have undergone periradicular surgical procedures. Likewise, little is known about the potential risks or sequelae involved in moving teeth that have had previous surgical intervention. Especially absent is the long-term prognosis of this type of treatment. During orthodontic tooth movement, the provision of endodontic treatment may be influenced by a number of factors, including but not limited to radiographic interpretation, accuracy of pulp testing, patient signs and symptoms, tooth isolation, access to the root canal, working length determination, and apical position of the canal obturation. Adjunctive orthodontic root extrusion and root separation are essential clinical procedures that will enhance the integrated treatment planning process of tooth retention in endodontic-orthodontic related cases.

An increased number of adult individuals are seeking orthodontic treatment due to improved awareness of dental esthetics and function. Adult patients present with unique challenges for the orthodontist such as extensive restorative work, missing teeth, thin alveolar bone, and bone loss. Additionally, they demand efficiency in scheduling and speedy treatment. Periodontally accelerated osteogenic orthodontics (PAOO) or surgically facilitated orthodontics (SFO) is a surgical procedure to accelerate orthodontic tooth movement and minimize the resultant periodontal complications. It works by applying a series of vertical cuts in the cortical part of the alveolar bone and applying bone graft to the area. The resultant inflammation accelerates bone turnover and the resultant orthodontic tooth movement. The corticotomy along with bone graft is believed to improve alveolar bone thickness, expanding the range of orthodontic tooth movements. Though the effects of SFO are documented in terms of tooth movement, in this case report we present the benefits of SFO on alveolar bone height and width with the use of CBCT, along with timing of orthodontic treatment and tooth movement.

To evaluate the effects of bone regeneration materials and orthodontic tooth movement (OTM) timing on tooth movement through alveolar bone defects treated with guided bone regeneration (GBR) utilizing xenografts (Bio-Oss) and alloplast (β-TCP). Twenty-four standard alveolar bone defects in six male beagle dogs were treated by GBR using either Bio-Oss or β-TCP (experimental), whereas the control defects were left empty. The defects were further grouped into early or late subgroups, depending on OTM timing after GBR (ie 1 month or 2 months, respectively). Rates of OTM were measured intraorally, while computed tomography scan images were used to assess bone density, alveolar bone height, second premolar displacement, and tipping tendency. Generally, the Bio-Oss early and Bio-Oss late subgroups recorded the lowest amount of tooth movement compared with other modes of GBRs assessed. Before OTM, the control group registered significantly lower bone height compared with the Bio-Oss and β-TCP groups ( P < .01). The control group was inferior on bone density and bone height compared with Bio-Oss and β-TCP. The Bio-Oss group had favorable radiologic features (higher alveolar bone level and bone density with less premolar tipping) but showed slower OTM than the control group. The late OTM subgroup had favorable radiologic features and showed faster tooth movement than the early OTM in the β -TCP group.

Introduction With an increasing demand for orthodontic treatment for adult patients, orthodontic professionals are constantly seeking novel strategies and technologies that can accelerate tooth movement in order to shorten the treatment period. For instance, in recent years, the influences of different surgical techniques on orthodontic tooth movement in the ipsilateral side of surgery were intensively investigated. Here, we attempt to examine if corticotomy could also affect the rate of tooth movement in the contralateral side of the surgery by using a rodent model. Materials and Methods 72 eight-week-old Sprague-Dawley rats were randomly divided into three groups as follows: the Control group (orthodontic treatment devices delivered only, no tooth movement), the orthodontic tooth movement (OTM) group (orthodontic treatment devices delivered and orthodontic treatment performed), and the Corticotomy + OTM group (remote corticotomy performed, orthodontic treatment devices delivered, followed by orthodontic treatment). The surgical procedure was conducted on the right side of the maxilla at the time of appliance placement and a force of 60 g was applied between the maxillary left first molar and maxillary incisors using nickel-titanium springs to stimulate OTM. The OTM distance and speed were tracked at 3, 7, 14, and 28 days post-surgery, followed by histological and immunohistochemical assessments. Results In comparison with orthodontic treatment only, the contralateral corticotomy significantly accelerated OTM. Furthermore, animals undergoing corticotomy + OTM presented with a greater number of osteoclasts on the compression side, stronger staining of the osteogenic marker on the tension side, and higher expression of an inflammatory marker than the OTM group animals. Conclusion Our current study demonstrates that remote corticotomy effectively accelerates alveolar bone remodeling and OTM. The study enriches our understanding of the regional acceleratory phenomenon (RAP) and offers an alternative strategy for accelerating OTM to shorten the orthodontic treatment period.

Autophagy of periodontal ligament inhibits inflammation and reduces the decline of bone density during orthodontic tooth movement of mice

Molecular effects of low-energy laser irradiation during orthodontic tooth movement

MOPs and accelerated tooth movement: A biased conclusion?