Surgical Removal of an Orthodontic Mini-Screw Displaced Into the Lateral Pharyngeal Space: A Case Report and Review of Pertinent Literature.

Oral and maxillofacial surgeons are often faced with the clinical challenge of foreign body displacement into the perioral tissues and soft tissues of the head and neck. This mainly occurs either because of trauma or inadvertently during dental treatment. In addition to the maxillary sinus, iatrogenic foreign body displacement during dental treatment could happen into one of the 16 distinct fascial spaces of the head and neck region. Commonly displaced foreign bodies related to dental treatment include tooth roots or fragments, local anesthetic needles, implants and restorations. The clinical sequelae of a displaced foreign body depend on its size, shape, anatomic location and proximity to vital structures. Although patients may remain asymptomatic for a considerable amount of time, retained foreign bodies result in persistent pain, recurrent infection and scarring of soft tissue due to inflammation, all of which may complicate delayed retrieval. In addition to the history, imaging modalities such as plain radiographs and computed tomography (CT) help in locating the displaced foreign body and its subsequent retrieval. Surgical retrieval may be attempted through intraoral, transcervical and endoscopic approaches. Additionally, surgery may be aided by real-time imaging such as fluoroscopy. The present report aims to detail a case of inadvertent displacement of an orthodontic mini-screw, commonly used as a temporary anchorage device (TAD), into the lateral pharyngeal space, while attempting placement in the mandibular retromolar area. The case report also describes the surgical retrieval procedure of the TAD screw using an intraoral approach and with fluoroscopy guidance using C-Arm radiographic imaging. This case is reported along with the pertinent review of literature, as it not only explains a rare complication of orthodontic mini-screw placement but also details a modality to remove displaced foreign bodies from fascial spaces of the head and neck, which are otherwise directly inaccessible.

[The use of an individualized mini plate for the distalization of teeth]. / Ispol'zovanie individualizirovannoi miniplastiny dlya distalizatsii zubov.

The case of treatment of a 32-year-old patient with complaints about the aesthetics of a smile and the absence of teeth 17 and 46 is presented. During the examination, it was established: the retraction position of the teeth in the frontal part of the upper jaw, the closure of the molars according to the II class of the second subclass of Engl (distal bite), the vestibular position of the teeth 13, 23. To change the spatial position of the lower jaw, the fixation of the bracket system on the upper jaw was performed. and also an individualized mini-plate was installed in the area of the zygomatic alveolar ridge on the right and left, for distalization of the dentition of the upper jaw with the help of orthodontic traction applied from the teeth to the mini-plates. This clinical example demonstrates the possibility of using individualized mini-plates for distalization of the upper dentition, as an alternative and more stable method of treatment in such clinical cases.

Effect of Erbium:YAG Laser Recycling on Mechanical Characteristics of Retrieved Orthodontic Mini-screws.

Introduction: This study aimed to evaluate the influence of two recycling methods on the mechanical and surface characteristics of orthodontic mini-screws. Methods: Thirty-six retrieved mini-screws were randomly classified into two equal groups. In the first group (laser recycled group (LG)), the Er:YAG laser (2940 nm, 5.5 W, 275 mJ, perpendicular to the mini-screws at a distance of 7-10 mm, 25 s) was used to recycle mini-screws. In the second group (phosphoric acid and sodium hypochlorite recycled group (ASG)), the mini-screws were kept in 37% phosphoric acid gel (10 minutes) and then placed in 5.25% sodium hypochlorite for 30 minutes. Eighteen new mini-screws were selected as the control group (CG). Maximum insertion torque (MIT), maximum removal torque (MRT), and fracture torque (FT) of all mini-screws were measured. A sample from each group was examined for the surface changes of the mini-screw and tissue remnants under a scanning electron microscope (SEM). Results: The mean MIT was significantly higher in both LG and ASG groups than the CG (P<0.001 and P=0.002, respectively). However, no significant difference was shown between the LG and ASG groups. The mean values of MRT and FT showed no significant difference between the groups. The amount of tissue remnants in the ASG group was significantly higher than that in the LG group. The evidence of porosity and corrosion was observed on the ASG mini-screw surface, and there was an increase in roughness on the LG mini-screw surface. Conclusion: The Er:YAG laser recycling of mini-screws is a proper method causing minimum damage to the screw surface.

Evaluation of osseointegration of Ti-6Al-4V alloy orthodontic mini-screws with ibandronate-loaded TiO2 nanotube layer.

Recently, the use of orthodontic mini-screws as an anchorage for orthodontic treatment is increasing, and the degree of osseointegration of the mini-screws affects the performance of orthodontic treatment. This study aimed to evaluate the biocompatibility and osseointegration of Titanium 6Aluminum 4Vanadium (Ti-6Al-4V) alloy orthodontic mini-screws with an ibandronate-loaded TiO2 nanotube (TNT) layer. The TNT layer was formed on the surface of the Ti-6Al-4V alloy orthodontic mini-screws and loaded with ibandronate. The TNT formed by anodic oxidation formed a completely self-organized and compact structure and was stably released for 7 days after loading with ibandronate. Mini-screws loaded with ibandronate were implanted into both tibias of rats, confirming rapid initial bone regeneration. We demonstrate that the release of stable ibandronate from the TNT layer of Ti-6Al-4V alloy orthodontic mini-screws can effectively improve biocompatibility and osseointegration.

Anti-biofilm and bystander effects of antimicrobial photo-sonodynamic therapy against polymicrobial periopathogenic biofilms formed on coated orthodontic mini-screws with zinc oxide nanoparticles.

BACKGROUND: The present study evaluated the anti-biofilm and bystander effects of antimicrobial photo-sonodynamic therapy (aPSDT) on the polymicrobial periopathogenic biofilms formed on mini-screws coated with zinc oxide nanoparticles (ZnONPs). MATERIALS AND METHODS: Thirty orthodontic identical mini-screws were divided into 6 groups (n = 5) as follows: 1. negative control: uncoated mini-screw + phosphate-buffered saline (PBS), 2. positive control: uncoated mini-screw + 0.2% CHX, 3. coating control: coated mini-screw + PBS, 4. antimicrobial photodynamic therapy (aPDT): coated mini-screw+light emitting diode (LED), 5. Antimicrobial sonodynamic therapy (aSDT): coated mini-screw+ultrasound waves, and 6. aPSDT: coated mini-screw+LED+ultrasound waves. Electrostatic spray-assisted vapor deposition was employed to coat ZnONPs on titanium mini-screws. The biofilm inhibition test was used to assess the anti-biofilm efficacy against polymicrobial periopathogenic biofilms including Porphyromonas gingivitis, Prevotella intermedia, and Aggregatibacter actinomycetemcomitans, and the results were shown as the percent reduction of Log10 colony-forming unit (CFU)/mL. Following each treatment, the gene expression levels of TNF-α, IL-1ß, and IL-6 were evaluated on human gingival fibroblast (HGF) cells via quantitative real-time polymerase chain reaction (qRT-PCR) to reveal the bystander effects of aPSDT on HGF cells. RESULTS: A significant reduction in log10 CFU/mL of periopathogens was observed in groups treated with aPDT, aSDT, aPSDT, and 0.2% CHX up to 6.81, 6.63, 5.02, and 4.83 log, respectively, when compared with control groups (P<0.05). 0.2% CHX and aPSDT groups demonstrated significantly higher capacity in eliminating the periopathogen biofilm compared with other groups (P<0.05). The qRT-PCR showed that the expression level of inflammatory cytokines was significantly down regulated in aPDT, aSDT, and aPSDT groups (P<0.05). CONCLUSION: It was found that the ZnONPs-mediated aPSDT could significantly reduce periopathogen biofilm as well as the expression level of inflammatory cytokines.

Enhancement of bioactivity and osseointegration in Ti-6Al-4V orthodontic mini-screws coated with calcium phosphate on the TiO2 nanotube layer.

Objective: This study evaluated the effect of cyclic pre-calcification treatment on the improvement of bioactivity and osseointegration of Ti-6Al-4V mini-screws. Methods: The experimental groups were: an untreated group (UT), an anodized and heat-treated group (AH), and an anodized treatment followed by cyclic pre-calcification treatment group (ASPH). A bioactive material with calcium phosphate was coated on the mini-screws, and its effects on bioactivity and osseointegration were evaluated in in vitro and in vivo tests of following implantation in the rat tibia. Results: As a result of immersing the ASPH group in simulated body fluid for 2 days, protrusions appearing in the initial stage of hydroxyapatite precipitation were observed. On the 3rd day, the protrusions became denser, other protrusions overlapped and grew on it, and the calcium and phosphorus concentrations increased. The removal torque values increased significantly in the following order: UT group (2.08 ± 0.67 N·cm), AH group (4.10 ± 0.72 N·cm), and ASPH group (6.58 ± 0.66 N·cm) with the ASPH group showing the highest value (p < 0.05). In the ASPH group, new bone was observed that was connected to the threads, and it was confirmed that a bony bridge connected to the adjacent bone was formed. Conclusions: In conclusion, it was found that the surface treatment method used in the ASPH group improved the bioactivity and osseointegration of Ti-6Al-4V orthodontic mini-screws.

Improvement of osseointegration of Ti-6Al-4V ELI alloy orthodontic mini-screws through anodization, cyclic pre-calcification, and heat treatments.

BACKGROUND: Mini-screws are widely used as temporary anchorages in orthodontic treatment, but have the disadvantage of showing a high failure rate of about 10%. Therefore, orthodontic mini-screws should have high biocompatibility and retention. Previous studies have demonstrated that the retention of mini-screws can be improved by imparting bioactivity to the surface. The method for imparting bioactivity proposed in this paper is to sequentially perform anodization, periodic pre-calcification, and heat treatments with a Ti-6Al-4V ELI alloy mini-screw. MATERIALS AND METHODS: A TiO2 nanotube-structured layer was formed on the surface of the Ti-6Al-4V ELI alloy mini-screw through anodization in which a voltage of 20 V was applied to a glycerol solution containing 20 wt% H2O and 1.4 wt% NH4F for 60 min. Fine granular calcium phosphate precipitates of HA and octacalcium phosphate were generated as clusters on the surface through the cyclic pre-calcification and heat treatments. The cyclic pre-calcification treatment is a process of immersion in a 0.05 M NaH2PO4 solution and a saturated Ca(OH)2 solution at 90 °C for 1 min each. RESULTS: It was confirmed that the densely structured protrusions were precipitated, and Ca and P concentrations, which bind and concentrate endogenous bone morphogenetic proteins, increased on the surface after simulated body fluid (SBF) immersion test. In addition, the removal torque of the mini-screw fixed into rabbit tibias for 4 weeks was measured to be 8.70 ± 2.60 N cm. CONCLUSIONS: A noteworthy point in this paper is that the Ca and P concentrations, which provide a scaffold suitable for endogenous bone formation, further increased over time after SBF immersion of the APH group specimens. The other point is that our mini-screws have a significantly higher removal torque compared to untreated mini-screws. These results represent that the mini-screw proposed in this paper can be used as a mini-screw for orthodontics.

The effects of different antiseptic mouthwash on microbiota around orthodontic mini-screw.

OBJECTIVE: This study aims to investigate the effects of different antiseptic mouthwash on microbiota around the mini-screw applied to patients undergoing fixed orthodontic treatment. MATERIALS AND METHODS: From patients who have been undergoing fixed orthodontic treatment and who have mini-screws in their mouth, a total of 38 patients were selected for the study consisting of 4 groups, each of which has 15 mini-screws. The patients were selected from the following groups: no use of mouthwash (Group 1), use of 0.12% chlorhexidine gluconate-containing mouthwash (Group 2), use of essential oils-containing mouthwash (Group 3), and use of 7.5% povidone-iodine-containing mouthwash (Group 4). Plaque indices and gingival indices of the patients were measured at the beginning (T0) and at their appointments 3 weeks later (T1). In addition, biological samples were collected from the sulcus around the mini-screw with the help of sterile paper point. RESULTS: The total number of microorganisms around the mini-screw in Group 2, Group 3, and Group 4 decreased significantly compared to Group 1. A significant decrease in Streptococcus oralis, Streptococcus mitis, Candida parapsilosis, total bacteria, plaque index, and gingival index count was observed in T1compared to T0. CONCLUSION: Antiseptic mouthwash in Group 2, Group 3, and Group 4 can be used to reduce the number of microbial microbiota around the mini-screw and to improve oral hygiene.

Mini-screw implant-supported pontics for the transitional management of missing permanent maxillary lateral incisors in children and adolescents: a review of currently available evidence.

AIM: To review currently available evidence regarding the use of mini-screw implant (MSI)-supported pontics for the transitional management of missing permanent maxillary lateral incisors in children and adolescents. METHODS: Indexed databases were searched until October 2019. The following inclusion criteria were imposed: (a) children and adolescents with missing permanent maxillary lateral incisor/s; (b) temporary replacement of missing permanent maxillary lateral incisors with MSI-supported pontics; (c) clinical and radiographic assessment of the outcome [MSI stability and/or alveolar bone (ALB) development]; and (d) follow-up after pontic placement. Commentaries, letters to the Editor, reviews, and studies in adult patients and/or patients with systemic/genetic diseases, with no follow-up, and without clinical and radiographic assessment of the outcome were excluded. RESULTS: Six out of 225 initially-identified studies were included. All studies were case-reports/series. A variability was observed among studies-assessed regarding the treatment protocol such as in the MSI dimensions, loading time and pontic retention protocol. Results from the included studies indicate that the MSI-supported pontics remained stable, with no infraocclusion and angular bony defect formation, ALB levels and bone density were maintained, and there was vertical ALB development during the follow-up period which ranged up to 99 months. Reported complications included MSI loss due to mobility, crown repair/replacement due to discoloration, and gingival impingement. CONCLUSIONS: The limited evidence shows that MSI-supported pontics are useful transitional restorations for missing permanent maxillary lateral incisors in children and adolescents; however, further well-designed clinical trials are needed in this regard.

Tratamento da Classe II-1 subdivisão, utilizando miniparafuso extra-alveolar no izc e aparelhos autoligáveis passivos ­ relato de caso / Class II-1 subdivision treatment using extra-alveolar mini screw in izc and passive self-ligating brackets ­ case report

As más oclusões de Classe II de Angle, de natureza dento-alveolar ou esquelética moderada, podem ser tratadas com ou sem exodontias de pré-molares, utilizando diversos recursos para ancoragem. O advento dos miniparafusos possibilitou uma ancoragem esquelética na distalização de molares, anulando os efeitos colaterais indesejados, por meio de um procedimento minimamente invasivo. Os parafusos extra-alveolares eliminaram ainda o inconveniente do posicionamento do corpo dos parafusos entre as raízes, permitindo maiores movimentos sagitais, sem a necessidade de reposicionamento dos miniparafusos ou utilização de cursores. Esse fato aumentou a eficiência do tratamento nas correções sagitais e simplificou a mecânica ortodôntica. A associação desse recurso de ancoragem com os aparelhos autoligáveis passivos com prescrições variáveis reduzem a quantidade de consultas, os níveis de força aplicada, necessidade de dobras no arco e a dependência de colaboração do paciente. Objetivo: Relatar um caso clínico no qual foi utilizado parafuso extra-alveolar na crista-infrazigomática como recurso de ancoragem, associado a aparelhos autoligáveis passivos na correção da Classe II-1 subdivisão direita. Conclusão: A associação dos parafusos extra-alveolares com o sistema de aparelhos autoligáveis passivos com prescrições variadas se mostraram eficientes na correção da má oclusão de Classe II subdivisão (AU)

Abstract Introduction: Angle Class II dentoalveolar or moderate skeletal malocclusions can be treated with or without premolar extraction using a variety of anchoring features. The advent of mini-screws allowed skeletal anchorage in molar distalization, nullifying unwanted side effects through a minimally invasive procedure. The extra-alveolar screws also eliminated the inconvenience of positioning the body of the screws between the roots, enabling greater sagittal movements, dispensing replacement of the mini-screws or cursors use. This fact increased treatment efficiency of sagittal corrections and simplified orthodontic mechanics. The association of this anchorage feature with passive self-ligating brackets reduces the number of consultations, the levels of applied force, the need for arch bending, and dependence of patient's collaboration. Objective: To report a clinical case in which the extra-alveolar screw was used in the IZC as an anchorage resource, associated with passive self-ligating brackets for the correction of Class II-1 subdivision. Conclusion: The association of extra-alveolar screws with passive self-ligating brackets system proved to be efficient in Class II subdivision malocclusion correction. (AU)

In vitro evaluation of osteoblast responses to carbon nanotube-coated titanium surfaces.

BACKGROUND: The effects of surface roughness and carboxyl functionalization of multi-walled carbon nanotubes (MWCNTs) mixed with collagen coated onto titanium (Ti) substrates on MC3T3-E1 osteoblasts were evaluated. METHODS: The proliferation, differentiation, and matrix mineralization were investigated using (1) smooth-surfaced Ti discs, (2) Ti discs coated with collagen and MWCNT (Ti-MWCNT), and (3) Ti discs coated with collagen and MWCNT-COOH (Ti-MWCNT-COOH) for applications in orthodontic mini screw implants (MSIs). The coatings were uniform when analyzed using scanning electron microscopy (SEM), and surface roughness was evaluated by surface profilometry that demonstrated similar surface roughness (R a , mean ± SD) in the MWCNT (0.83 ± 0.02 µm) and MWCNT-COOH (0.84 ± 0.01 µm) groups. MTT (3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide) assay was performed after days 1, 3, and 7 to assess proliferation. Alkaline phosphatase (ALP)-specific activity was assessed after day 7 to quantify differentiation. Alizarin red staining was measured after day 28 to quantify matrix mineralization. All data were analyzed with JMP Pro11 software (SAS, USA) with a statistical significance of p < 0.05. RESULTS: Surface profilometry demonstrated similar surface roughness (R a , mean ± SD) in the MWCNT (0.83 ± 0.02 µm) and MWCNT-COOH (0.84 ± 0.01 µm) groups. On day 7, ALP assay showed that MWCNT-COOH (mean ± SD 0.98 ± 0.26 U/µg of protein) enhanced cell differentiation when compared to the uncoated group (p = 0.05). Alizarin red staining after 28 days of cell culture revealed that MWCNT-COOH (mean ± SD 1.5 ± 0.2 OD405) increased (p = 0.03) matrix mineralization when compared to the uncoated group (0.9 ± 0.09 OD405). CONCLUSIONS: This study showed that coatings containing MWCNT-COOH (increased hydrophilic surface chemistry) influence osteoblast proliferation, differentiation, and matrix mineralization and should be further studied for applications in orthodontic MSIs.

The effect of insertion angle on orthodontic mini-screw torque.

BACKGROUND: Primary stability is an important factor for the clinical success of orthodontic mini-screws. The present study made an attempt to evaluate the effect of insertion angle changes on the maximum insertion and removal torque of orthodontic mini-screws. MATERIALS AND METHODS: In this experimental study, 72 mini-screws (Dual Top Anchor System, Jeil, 1.6 mm diameter, 8 mm length) were used. They were randomly divided into four equal groups and inserted in poly-carbonate plates with 3 mm thickness. Then, their maximum insertion torque (MIT) and maximum removal torque (MRT) were recorded using a digital torque tester/screwdriver. Each group had a different insertion angle (90°, 75°, 60° and 45°). The data were analyzed by SPSS software (version 18) using one-way ANOVA and post-hoc Tukey's tests. The level of significance was set at 0.05. RESULTS: The maximum MIT was observed in 45° insertion angle (14.84 Ncm) and the minimum MIT was reported in 75° insertion angle (12.66 Ncm). The maximum MRT was observed in 45° insertion angle (23.21 Ncm) and the minimum MRT was reported in the 90° insertion angle (17.43 Ncm). CONCLUSION: Oblique insertion of the mini-screws results in higher insertion and removal torques and probably more primary stability compared to the vertical insertion.

Stress distribution in the mini-screw and alveolar bone during orthodontic treatment: a finite element study analysis.

OBJECTIVE: This study aimed to investigate the reason for high failure rates of mini-screws during orthodontic treatment. We hypothesized that decreasing the length of the mini-screw outside the bone relative to the length inside the bone (outside/inside length ratio) and equalising it to the tooth crown/root ratio would lead to increased stability of the mini-screw against lateral loading when assessed using finite element analysis. METHODS: We analysed stress distribution of mini-screws in the cortical and trabecular bone and von Mises stress levels when a 2-N force was applied to the head of four mini-screws of 6, 8, 10 and 12 mm in length. The direction of the force was perpendicular to the major axis of the screws. RESULTS: Stress levels of screws in cortical bone increased in proportion to the length of mini-screws outside the bone. The length of mini-screws inside the bone did not affect stress levels in the cortical bone. CONCLUSIONS: The results of this finite element analysis indicate that to stabilize the mini-screw, controlling the screw length outside the bone is more important than controlling the outside/inside length ratio.

Insertion and removal torques according to orthodontic mini-screw design / 대한치과교정학회지

OBJECTIVE: This study was designed to analyze the primary and secondary stability characteristics of orthodontic mini-screws of tapered design when compared with the cylinder mini-screw. METHODS: A total of 48 mini-screws were placed into the buccal alveolar bone of the mandible in 6 male beagle dogs. Comparison was made between tapered and cylinder type mini-screws (Biomaterials Korea, Seoul, Korea). Maximum insertion torque (MIT) was measured using a torque sensor (Mark-10, MGT 50, USA) during installation, and maximum removal torque (MRT) was recorded after 3 and 12 weeks of loading. RESULTS: Taper mini-screws showed a higher MIT value of 22.3 Ncm compared with cylinder mini-screw showing 13.6 Ncm (p < 0.001). The MRT of the taper mini-screw showed a significantly higher value of 9.1 Ncm than those of cylinder mini-screw of 5.7 Ncm at 3-weeks after installation (p < 0.05). However, there was no difference in the MRT value between the taper and cylinder mini-screws at 12 weeks of loading. CONCLUSIONS: These results showed that the high insertion torque of the taper mini-screw design increases initial stability until 3 weeks of loading, but does not have any effect on the secondary stability at 12 weeks of loading.

Evaluation of insertion of torque and pull-out strength of mini-screws according to different thickness of artificial cortical bone / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to evaluate the mechanical performance of mini-screws during insertion into artificial bone with use of the driving torque tester (Biomaterials Korea, Seoul, Korea), as well as testing of Pull-out Strength (POS). METHODS: Experimental bone blocks with different cortical bone thickness were used as specimens. Three modules of commercially available drill-free type mini-screws (Type A; pure cylindrical type, Biomaterials Korea, Seoul, Korea, Type B; partially cylindrical type, Jeil Medical, Seoul, Korea, Type C; combination type of cylindrical and tapered portions, Ortholution, Seoul, Korea), were used. RESULTS: Difference in the cortical bone thickness had little effect on the maximum insertion torque (MIT) in Type A mini-screws. But in Type B and C, MIT increased as the cortical bone thickness increased. MIT of Type C was highest in all situations, then Type B and Type A in order. Type C showed lower POS than Type A or B in all situations. There were statistically significant correlations between cortical bone thickness and MIT, and POS for each type of the mini-screws. CONCLUSION: Since different screw designs showed different insertion torques with increases in cortical bone thickness, the best suitable screw design should be selected according to the different cortical thicknesses at the implant sites