Orthodontic Microimplants Research Articles

Novel cytotoxicity of nano-coated orthodontic micro-implants: An in vitro study

Objectives: Many attempts have been made to modify the surface of orthodontic micro-implants and prevent the development of microbes by coating them with antimicrobial nanoparticles (NPs). The purpose of the present study was to evaluate the cytotoxicity of different NPs, namely, TiO2 and zinc oxide (ZnO) NPs, that are used to coat titanium orthodontic micro-implants. Material and Methods: Thirty orthodontic micro-implants were included in this study. Those were divided into three groups: control group without coating, TiO2-coated orthodontic micro-implants, and TiO2- and ZnO-coated orthodontic micro-implants. Scanning electron microscope, energy-dispersive spectroscopy (EDS), and cytotoxicity tests were applied for all groups. Results: The results of scanning electron microscopy and EDS showed effective deposition of the titanium oxide layer onto the micro-implants. The ZnO layer applied on the micro-implants exhibited superior physicochemical characteristics in comparison to the uncoated samples with no significant cytotoxicity. Conclusion: Both NPs showed biocompatibility with the oral tissues.

Antimicrobial behavior of nanocoated orthodontic micro-implants: An in vitro study.

The need to overcome the failure of orthodontic micro-implants which might reach to 30% has led to the development of different methods, one of which is nanoparticle deposition. To evaluate the anti-microbial efficiency of TiO2 and ZnO nanoparticles (NP) when used as a coating for orthodontic micro-implants. Thirty titanium alloy micro-implants were used in the presented study. They were divided into three groups according to the coating method and the coating materials used: the control group without surface coating; the titanium dioxide (TiO2)-coated group, in which direct current (DC) spattering was used to coat the micro-implants with a TiO2 layer; and the TiO2 and zinc oxide (TiO2ZnO)-coated group, in which the micro-implants were coated with a TiO2 layer via direct current (DC) spattering and a zinc oxide (ZnO) layer via laser vacuum. The micro-implant surfaces were characterized using scanning electron microscopy (SEM) and an energy-dispersive spectrometer (EDS). The antibacterial susceptibility was assessed using gram-positive and gram-negative bacteria. SEM and EDS tests confirmed the coating of the micro-implants in the TiO2- and TiO2ZnO-coated groups. The micro-implants in the TiO2- and TiO2ZnO-coated groups demonstrated higher antibacterial ability than the control group. This study demonstrated the significance of improving the surface of orthodontic micro-implants by coating them with TiO2 and ZnO nanoparticles to improve osseointegration and prevent biofilm formation.

Treatment of Class II Malocclusion With Orthodontic Microimplant Anchorage

IntroductionThe objective of the study was to compare the effects of orthodontic microimplant anchorage (MIA) and conventional extraoral arch anchorage (EAA) on tooth structure and oral inflammatory response in patients with Class II Division I malocclusion. MethodsA total of 104 patients with Class II malocclusion were enrolled and were randomly assigned to receive MIA or EAA treatments. Clinical efficacy was assessed at 6 months after treatment by measuring molar shift, convex distance, and hinge angle difference between maxillary and mandibular incisors. X-ray was performed for tissue evaluations. The levels of cell adhesion molecule-1 (CAM-1), matrix metalloproteinase-2 (MMP-2), and proinflammatory cytokines in gingival sulcus fluid were measured using enzyme-linked immunosorbent assay to assess inflammatory responses to the implants. ResultsOur study demonstrated superior efficacy of MIA compared to EAA in terms of overall efficacy, molar shift, convex distance between upper and middle incisors, as well as hinge angle difference between upper and middle incisors. MIA also showed greater efficacy in reducing tissue fix-point measurements, including saddle point–nasal root point–superior alveolar seat point (SNA), alveolar seat point–nasal root point–inferior alveolar seat point (ANB), overlying (OJ), and overbite (OB). ConclusionsMIA is a novel orthodontic treatment that showed stronger efficacy in inducing molar shift and correcting soft/hard tissue positions, whilst generating suppressed inflammatory responses. Our study could have significant implications for practice in the orthodontic treatment of Class II malocclusion.

Treatment of an Open Bite Patient with Maxillary Expansion and Micro-Implant Anchorage

The purpose of this case report was to describe the treatment of an open bite patient with palatal expansion and micro-implant anchorage. A 21-year-old female presented with a chief complaint of openbite. Clinical examination showed straight profile with mild crowding. Intraorally, she exhibited both Class I molar relationship, 1.5 mm negative overbite. Due to the transverse discrepancy, upper molars were palatally tipped, while lower molars were buccally tipped. The maxillary arch expansion was performed using rapid palatal expander. After maxillary expansion, orthodontic micro-implants were used for upper molars intrusion. After orthodontic treatment, the patient showed proper overjet and overbite, and good retention after 2 years. Open bite can be corrected by counterclockwise autorotation of the mandible obtained with intrusion of molars and it is critical to eliminate the causative agent.

Survival Analysis of Orthodontic Micro-Implants: A Retrospective Study on the Effects of Patient-Related Factors on Micro-Implant Success

The purpose of this study was to investigate the effects of patient-related factors such as anteroposterior and vertical skeletal patterns and alveolar bone density on the success rate of micro-implants. Cases of orthodontic micro-implants (n = 404; diameter, 1.6 mm; length, 6 mm) were investigated in 164 patients (127 women, 37 men; mean age, 23.6 ± 5.8 years). Cortical bone thickness and alveolar bone density were measured using diagnostic cone-beam computed tomography to examine their effects on the micro-implant’s survival. Moreover, anteroposterior and vertical facial patterns were considered as independent variables for the success of micro-implants. Marginal survival analysis was performed by analyzing the time from implant placement to the removal of the failed micro-implants, or to the end of treatment for successful micro-implants. Variables including age, sex, implantation side, implantation site, root proximity, and type of loading (immediate vs. delayed) were also assessed. In total, 347 (85.9%) of the 404 micro-implants were successful. The mean loading time was 12.4 ± 4.3 months. Marginal survival analysis showed that the effects of the anteroposterior and vertical facial patterns on the risk of failure were not statistically significant. The factors significantly associated with the micro-implant loading time were cortical bone density, root proximity, and micro-implants replanted in the same site. In conclusion, our findings indicate that anteroposterior and vertical skeletal patterns are not associated with the success of orthodontic micro-implants. Cortical bone density may be associated with the micro-implant’s success.

Methods of Anterior Torque Control during Retraction: A Systematic Review.

Background: There are various methods of controlling the inclination of the incisors during retraction, but there is no evidence as to the advantages of some methods over others. The purpose of this systematic review and meta-analysis was to determine the effectiveness of the methods used to control torque during anterior teeth retraction. Methods: In accordance with the PRISMA guidelines, the main research question was defined in the PICO format [P: patients with complete permanent dentition; I: the maxillary incisor torque after (I) and before I retraction with straight-wire appliance and different modes of torque control; O: statistically significant differences in torque values of the upper incisors after orthodontic treatment]. The MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials databases were searched for keywords combining: retraction orthodontics, torque control orthodontics, torque orthodontics, inclination orthodontics, torque control retraction. The articles were subjected to risk of bias and quality analyses with the ROBINS-I protocol and the modified Newcastle–Ottawa QAS, respectively. Meta-analyses were performed with both fixed- and random-effects models. Results: 13 articles were selected in which total number of 580 subjects took part. In all studies, incisors were retroclined during retraction by 2.46° (mean difference), which was statistically significant. Considering the articles separately, the differences in torque between the study group and the control group were statistically significant in six articles. The Q statistic was 36.25 with p = 0.0003 and I2 = 66.9%, which indicated a high level of study heterogeneity. Conclusion: Both properly performed corticotomy and en-masse retraction using orthodontic microimplants seem to be the most effective and scientifically validated methods of torque control. Further high-quality research is needed to perform better quality analyses and draw more reliable conclusions.

Incorporation of Plant Extracted Hydroxyapatite and Chitosan Nanoparticles on the Surface of Orthodontic Micro-Implants: An In-Vitro Antibacterial Study.

In our study, the structural and morphological applications of hydroxyapatite and chitosan nanoparticles and coated micro-implants were assessed for their ability to combat oral pathogenic bacteria. The hydroxyapatite, as well as chitosan nanoparticles, were synthesized from the Salvadora persica plant. The crystal morphology, phase composition, particle size, and surface functional groups of the nano-samples were analyzed via classical examinations and energy dispersive X-ray analysis. The prepared nanoparticles have been examined for antibacterial activity against four common oral bacterial strains. The antimicrobial effect was also assessed by the Live/Dead BacLight technique in combination with confocal scanning laser microscopy. Titanium micro-implants were coated with regular hydroxyapatite (HAP) and chitosan nanoparticles, and the surface was characterized by scanning electron microscopy. The analysis asserted elemental composition of the prepared nanoparticles and their textural features, metal crystallization, and functional bonds. The antibacterial activity of the nanoparticles was evaluated against oral pathogenic microorganisms by the disc diffusion method, minimum bacterial concentration (MBC), and minimum inhibitory concentration (MIC). Chitosan nanoparticles showed (MICs) of 8 μg mL−1 for (Streptococcus salivarius, Streptococcus mutans and Enterococcus faecalis), and 16 μg mL−1 for Streptococcus sanguinis. HAP nanoparticles showed (MICs) of 16 μg/mL for E. faecalis, and S. sanguis, 8 μg/mL for S. salivarius and finally 4 μg/mL for S. mutans. HAP nanoparticles showed enhanced antibacterial activity and more obvious damage in the bacterial cell membrane than that of synthesized chitosan nanoparticles. The prepared nanoparticles could successfully coat titanium microplates to enhance their efficiency.

Effect of Microimplant Neck Design with and without Microthread on Pullout Strength and Destruction Volume.

The microthread neck concept has been applied to dental implants. This study investigated the pullout strength and destruction volume of orthodontic microimplants with and without the microthread neck design. Fifteen microimplants (diameter: 1.5 × 10 mm) of three types (Types A and B: without microimplant neck; Type C: with microimplant neck) were tested. The insertion torque (IT), Periotest value (PTV), horizontal pullout strength (HPS), and horizontal destruction volume (HDV) of each type were measured. Kruskal–Wallis H test and Dunn’s post-hoc comparison test were performed to compare the measured values of the three types of microimplants. The correlations of the measured values were used to perform the Spearman’s correlation coefficient analysis. The ITs of Types B (8.8 Ncm) and C (8.9 Ncm) were significantly higher than those of Type A (5.2 Ncm). Type B yielded the lowest PTV (4.1), and no statistical differences in PTV were observed among the three types. Type A had a significantly lower HPS (158.8 Ncm) than Types B (226.9 Ncm) and C (212.8 Ncm). The three types did not exhibit any significant differences in the HDV. The results of the Spearman’s correlation coefficient test revealed that HDV (ρ = 0.710) and IT (ρ = 0.813) were strongly correlated with HPS, whereas for PTV and HPS, it was not. HPS was strongly and significantly correlated with HDV. The orthodontic microimplant with a microimplant neck design did not perform better than that without a microthread in the mechanical strength test.

Effects of bicortical anchorage on pterygopalatine suture opening with microimplant-assisted maxillary skeletal expansion

The objectives of this study were to evaluate the effects of bicortical engagement by microimplants with maxillary skeletal expanders on pterygopalatine sutures opening and to analyze the postexpansion skeletal changes associated with it. Eighteen subjects treated with maxillary skeletal expanders were examined for pterygopalatine suture openings. Eight subjects who showed no evidence of the suture opening were assigned to the nonsplit group (NG), whereas 10 subjects with opened sutures were assigned to the split group (SG). Preexpansion and postexpansion cone-beam computed tomography images were superimposed for each group, and the changes in the 2 groups were compared. Finally, cone-beam computed tomography volumes were reoriented along the axis of each microimplant to check the bicortical engagement of the 4 microimplants. There was a significant correlation between the bicortical engagement of the orthodontic microimplants and the pterygopalatine suture opening (P=0.0003). In the NG, the average amount of transverse expansion measured at the center of resistance of the maxillary first molars, anterior nasal spine, and posterior nasal spine (PNS) was 4.33mm, 2.22mm, and 1.58mm, respectively, whereas the transverse expansion in the SG was 5.29mm, 2.21mm, and 2.46mm, respectively. The magnitude of transverse expansion at PNS was significantly higher in the SG than in the NG (P=0.036). The PNS also showed a significant anterior displacement in the SG (0.89mm) compared with the NG (0.06mm)(P=0.033). Bicortical microimplant anchorage is essential for pterygopalatine suture opening in microimplant-assisted maxillary skeletal expansion, which may result in further skeletal expansion and forward movement in the posterior part of the palatomaxillary complex.

Effect of 808 nm Semiconductor Laser on the Stability of Orthodontic Micro-Implants: A Split-Mouth Study.

Background: To evaluate the effect of photobiomodulation (PBM) on orthodontic micro-implants (n = 44; 14 women, 8 men). Methods: PBM with 808 nm diode laser was applied immediately, 3, 6, 9, 12, 15, and 30 days post the implantation. Results were assessed within same time frames and additionally after 60 days to check for implants stability using the Periotest device. Patients pain experiences following the first day post-treatment and potential loss of micro-implants after 60 days were recorded. The procedure involved insertion of mini-implants in the maxilla for the laser group (L, n = 22) and negative control group (C, n = 22). Irradiation was carried buccally and palatally with respect to the maxillary ridge (2 points). The energy per point was 4 J (8 J/cm2), total dose was 56 J. Results: Patients did not report significant differences in terms of pain experiences comparing the L and C groups (p = 0.499). At 30 days post-treatment, higher secondary stability of implants was observed in the laser group (Periotest Test Value, PTV 6.32 ± 3.62), in contrast to the controls (PTV 11.34 ± 5.76) (p = 0.004). At 60 days post-treatment, significantly higher stability was recorded in the laser group (PTV 6.55 ± 4.66) compared with the controls, PTV (10.95 ± 4.77) (p = 0.009). Conclusions: Application of the 808 nm diode laser increased secondary micro-implant stability.

Bioactive Antibacterial Modification of Orthodontic Microimplants Using Chitosan Biopolymer

Titanium alloy (Ti6Al4V)-based microimplants are extensively used as anchorage units in orthodontic treatment; however, they have a high failure rate (10 to 30%). This study aimed to enhance the survivability of these small implants by improving their bioactive and antibacterial properties, via modifying their surface with chitosan. For a stable covalent bond, microimplant surfaces were first functionalized with 3-triethoxysilylpropylamine (APTES) and then grafted either with a succinic acid or polyacrylic acid spacer, followed by attachment with chitosan. Validity tests were conducted on titanium alloy disk (TI) specimens treated with the same chemical process (TI specimens were used to avoid the practical difficulties in testing the small and complex-shaped microimplants). The results confirmed successful APTES functionalization and grafting of succinic- or polyacrylic acid. Anchoring of chitosan was confirmed via X-ray photoelectron spectroscopy (XPS) and confocal laser scanning microscopy (CLSM); furthermore, the anchoring ability of succinic acid, as a spacer, for chitosan was superior to that of polyacrylic acid. Chitosan-modified TI specimens (TI-SA-Ch) showed better biocompatibility with pre-osteoblastic MC3T3-E1 cells, as confirmed from their enhanced adhesion, proliferation, and from cell viability analysis. Biofilm formation of Streptococcus mutans and Streptococcus sobrinus was effectively reduced by 53% and 31%, respectively, on the surface of TI-SA-Ch. These results clearly indicated that chitosan modification might be a promising approach to enhance the bioactive- and antibacterial properties of orthodontic microimplants, and thus, increase their stability in the jaw bone in clinical practice.

Evaluation of different force magnitude to orthodontic microimplants on various cortical bone thickness – Three-dimensional finite element analysis

Aims: The aim of this study was to determine appropriate range of cortical bone thickness (CBT) to adequately support microimplants and optimum force magnitude on microimplants for minimal stress distribution. Settings and Design: Three-dimensional (3D) CAD models of the desired implant features and cylindrical bone piece of desired height and thickness were exported to FEA software, and variable load was applied on range of different CBT to determine the compressive radial stress and maximum failure load. Subjects and Methods: it is clearly said that CBT of various thickness which will represent human maxilla and mandibular bone. The force magnitudes ranging from 15 g to 150 g (in range of 15 g, 50 g, 85 g, and 150 g) were taken to simulate typical orthodontic forces loaded onto microimplant. Statistical Analysis Used: Statistical data were analyzed by IBM SPSS Statistics for windows Version 20.0 (IBM Corp., Armonk, NY, USA) software. For quantitative data analysis, ANOVA test was used. Results: For CBTs of 0.5, 1.5, 2.5, and 3.0 mm, the maximum force magnitudes that could be applied safely were 533.7, 551.7, 552.3, and 552.9, respectively. Even though there was no difference statistically, the amount of displacement for CBT 1.5–3.0 mm is comparatively less than for 0.5 mm. CBT value of 1.5–3.0 mm might be appropriate for microimplant stability. Conclusions: For the purpose of diminishing orthodontic microimplant failure, an optimal force that can be safely loaded onto a microimplant should not exceed a value of around 533–553 g. The CBT of 1.5–3.0 mm might be considered appropriate for the stability of microimplant.

Posterior Available Space for Uprighting Horizontally Impacted Mandibular Second Molars Using Orthodontic Microimplant Anchorage.

Treatment of horizontally and deeply impacted mandibular molars is challenging for both orthodontists and oral surgeons because of the limited access and anchorage control. We report on two patients who had horizontally and mesially impacted mandibular second molars (MM2s). Both patients were treated by a surgical orthodontic approach, and the crowns of the impacted teeth were brought into the arches by closed forced eruption. Mesially impacted MM2s were uprighted with orthodontic microimplants, inserted in the retromolar area, and then moved into their ideal position. The first patient was in an active growing stage, while the second patient was beyond the active growing stage. Therefore posterior available space (PAS) should be analyzed before treatment of impacted MM2s to prevent periodontal problems after uprighting of impacted teeth. If PAS is not enough for uprighting impacted MM2s, alternative treatment should be considered based on the stage of growth.

Surface characteristics and mechanical behavior of retrieved orthodontic microimplants

To observe the surface characteristics and mechanical behavior of retrieved microimplants under clinically simulating experimental conditions and to investigate the feasibility of reuse of microimplants. The microimplants, inserted at different angles, were retrieved from the patients (RMIP) and the artificial bone (RMIA). Surface characteristics, including morphologic changes of tips and thread edges, length reduction, and surface compositional variation, were evaluated using a field emission scanning electron microscope, a stereoscopic microscope, and energy-dispersive X-ray spectroscopy, respectively. Mechanical behavior comprising maximum insertion torque (MIT) and insertion time was tested with the artificial bone under clinically simulating conditions. The tips and thread edges were worn out to various degrees in retrieved microimplants and thin deposits were observed on the surface in the RMIP group. Traces of foreign elements, such as iron, sulphur, and calcium, were detected on the surface of RMIP. Both MIT and insertion time of retrieved microimplants were increased compared to their initial use, and were much greater in RMIP. The increases of MIT were seen in all groups inserted at the insertion angle of 45° compared with 90°, although the differences were not statistically significant. Retrieved microimplants exhibited different degrees of changes on surface characteristics and mechanical behavior, with more changes in RMIP. The reuse of microimplants for immediate relocation in the same patient may be acceptable; however, postponed relocation and allogeneic reuse of microimplants are not recommended in clinical practice.

Influence of antibiotic prophylaxis on the stability of orthodontic microimplants: A pilot randomized controlled trial.

The aims of this 2-arm parallel pilot randomized controlled trial were to investigate the influence of antibiotic prophylaxis on the stability of orthodontic microimplants and to evaluate the efficacy of systemic inflammatory marker measurements in detecting infections in tissues surrounding microscrews. Orthodontic patients requiring en-masse distalization in the maxilla received antibiotics or a placebo before microimplant placement. Eligibility criteria included 13years of age, and good general and oral health. Exclusion criteria comprised allergy to antibiotics, severe systemic allergy, heart and kidney diseases, and recent antibiotic treatment. Stability of the microimplants was the primary outcome; inflammation of the tissues surrounding the microscrews, pain related to the microimplantation, and serum levels of inflammatory markers were the secondary outcomes. Randomization in a 1:1 ratio was performed by auxilliary staff via a flip of a coin between 2 participants of the same sex and developmental stage, and the "winner" was allocated to the intervention group. Pharmaceutically prepared identical capsules with either amoxicillin (intervention) or glucose (control) given 1hour before microimplant placement according to the allocation provided blinding of the participants. Subsequently, 1 clinician unaware of the allocation inserted the microimplants and assessed the outcomes, which simultaneously blinded the operator-assessor. Blood samples for laboratory analysis of inflammatory markers were collected a day before and 1, 3, and 7days postoperatively. Out of 80 participants initially assessed for eligibility, 41 received the randomized allocation. Three patients were lost to follow-up. Eventually, data of 18 and 20 participants (mean age, 20.4±5.9years) were available for analysis in the intervention and control groups, in which 1 and 2 patients lost a microimplant, respectively, resulting in odds ratio of 0.53 (95% confidence interval [CI], 0.0084-11.23; P=1.0). The odds ratio for inflammation development was 1.22 (95% CI, 0.34-4.38), and the odds ratio for feeling milder pain was 1.174 (95% CI, 0.350-3.941) in the intervention compared with the control group, but the result was not statistically significant (P=0.758; P=0.795, respectively). The inflammatory marker levels did notincrease due to either microimplantation (procalcitonin, P=0.445; C-reactive protein, P=0.4) or peri-implantitis. Antibiotic prophylaxis slightlydecreased the levels of the biomarkers in the intervention group; however, the results were not statistically significant (P=0.68; P=0.908, respectively). No harms caused by the microimplantation procedure or drug intake were noted. Antibiotics provided no benefit in terms of microimplant stability, inflammation of soft tissues, or postoperative pain in our pilot sample. Measurements of serum levels of inflammatory markers were inefficient in detecting soft tissue inflammations. These initial results should be interpreted with caution until validated by a large multicenter definitive trial. This trial was not registered. The protocol was not published before trial commencement. The trial was funded by Wroclaw Medical University; grant number pbmn91 and supported by Diagnostyka.

Tooth Root Injury and Orthodontic Microimplant Fracture Caused by Its Incorrect Placement: Case Report

The purpose of this case report was to elucidate the condition after tooth injury while drilling and orthodontic microimplant fracture caused by its incorrect positioning. Among the investigation methods were CT, pulp vitality test, and endo-ice. That case clearly demonstrates and supports opinion of other authors that injury of periodontium and tissues of the root while drilling and placement of the microimplants can cause no significant disturbances in the future. Even in case of drilling in close proximity to root canals.

Evaluation of factors influencing the success rate of orthodontic microimplants using panoramic radiographs.

ObjectiveThe purpose of this study was to investigate factors influencing the success rate of orthodontic microimplants (OMIs) using panoramic radiographs (PRs).MethodsWe examined 160 OMIs inserted bilaterally in the maxillary buccal alveolar bone between the second premolars and first molars of 80 patients (51 women, 29 men; mean age, 18.0 ± 6.1 years) undergoing treatment for malocclusion. The angulation and position of OMIs, as well as other parameters, were measured on PRs. The correlation between each measurement and the OMI success rate was then evaluated.ResultsThe overall success rate was 85.0% (136/160). Age was found to be a significant predictor of implant success (p < 0.05), while sex, side of placement, extraction, and position of the OMI tip were not significant predictors (p > 0.05). The highest success rate was observed for OMIs with tips positioned on the interradicular midline (IRML; central position). Univariate analyses revealed that the OMI success rate significantly increased with an increase in the OMI length and placement height of OMI (p = 0.001). However, in simultaneous analyses, only length remained significant (p = 0.027). Root proximity, distance between the OMI tip and IRML, interradicular distance, alveolar crest width, distance between the OMI head and IRML, and placement angle were not factors for success. Correlations between the placement angle and all other measurements except root proximity were statistically significant (p < 0.05).ConclusionsOur findings suggest that OMIs positioned more apically with a lesser angulation, as observed on PRs, exhibit high success rates.

Physicochemical Properties of Advanced Nanostructured Materials for Dental Microimplant Coatings

An important aspect of orthodontic microimplants is represented by biocompatibility and avoidance of infection development at living tissue surrounding it. Therefore, nanotechnology has the ability to improve this issue by coating microimplants with metal oxides type nanomaterials possessing antimicrobial effect. Some features of advanced nanostructured materials used as implant coatings, such as composition, structure, specific surface area, porosity, shape and size are factors that make them suitable as antimicrobial agents. The present work deals with the structural and morphological studies of ZnO and TiO2 nanoparticles used to combat oral diseases. Coating microimplants with nanosized titanium oxide (TiO2) and zinc oxide (ZnO) may improve conditions for osseointegration in accordance with preventing oral infection. These metal oxides nanopowders were synthesized using sol-gel method. Structural and morphological investigation were carried out by XRD and FTIR spectra, SEM-EDX and TEM images respectively. XRD and FTIR analyses confirmed metal oxides crystallization and metal oxide bonds. SEM-EDX and TEM features confirmed elemental composition of these nanoparticles and their textural characteristics such as shape, size, porosity and agglomeration degree.

Effects of UV treatment on orthodontic microimplant surface after autoclaving

이 연구의 목적은, 마이크로임플란트의 보관기간과 증기고압멸균이 표면의 탄소함량에 미치는 영향과, 자외선 처리를 통해 탄소함량을 감소시킬 수 있는가를 조사하는 것이다. 보관기간의 영향을 조사하기 위해, 11년 동안 4개의 다른 시점에서 제작된 4개의 마이크로임플란트 그룹을 비교 실험하였고, 증기고압멸균과 자외선 처치의 효과를 평가하기 위해서는 2개 그룹 (새로 제작된 마이크로임플란트와 제조 후 11년 경과된 마이크로임플란트)을 사용하여 실험하였다. 물 접촉각 실험, 세포활성 검사를 사용하여 표면 탄소함량이 마이크로임플란트의 생물학적 특성에 미치는 영향도 함께 조사하였다. 실험결과, 11년의 보관기간 동안 마이크로임플란트 표면의 탄소함량은 점차 증가함을, 또한 증기고압멸균에 의해서 탄소함량이 증가됨을, 그리고 자외선 처리를 통해서 탄소함량을 유의하게 감소시킬 수 있음을 관찰하였다. 한편, 마이크로임플란트 표면의 탄소함량 감소에 따라 세포활성에는 주목할 변화가 없었으나 표면의 초친수성이 증가됨을 관찰하였다. 이 결과로부터, 마이크로임플란트의 긴 보관기간과 증기고압멸균처리는 표면의 탄소함량을 증가시키지만 자외선 처리는 마이크로임플란트 표면의 탄소함량을 감소시키고 초친수성을 증가시키므로 마이크로임플란트의 안정성 향상을 유도할 수 있을 것이라는 결론을 얻었다.

The Effect of Anchor Volume on the Mechanical Strengths of Orthodontic Micro-Implants

Anchor volume (AV) might be an important factor affecting mechanical strengths of micro-implant. To investigate the correlation between AV and three mechanical strengths (IT: insertion torque; RF: resonance frequency; HPS: horizontal pullout strength), 55 micro-implants (diameter 1.5 mm: Type A, B, C; diameter 1.3 mm: Type D and E) were driven into the artificial bones at a 7-mm depth. The RF, IT, HPS and AV were measured. One-way analysis of variance (ANOVA) with Tukey Honestly Significant Difference (HSD) post comparison and Pearson’s correlation were used to detect significant differences. Null hypothesis states that there was no statistically significant correlation between AV and these three forces (IT, RF, and HPS). Type A and Type D had the lowest IT (4.2 Ncm). Type C had the highest RF (9.9 KHz) in the stability test, and Type B had the greatest HPS (190.9 Ncm) in the resistance test. There was significant correlation between the IT and HPS. AV was significantly correlated with RF, IT, and HPS. The null hypothesis was rejected. In this study, each of these brands had its distinct advantages in the RF, IT, and HPS. Moreover, inner diameter/outer diameter ratio and AV affect the magnitude of HPS.