Effectiveness of different intrusion modes of maxillary anterior teeth with mini-implants in clear aligner treatment: a three-dimensional finite element analysis.

BACKGROUND: The intrusion of maxillary anterior teeth is often required and there are various intrusion modes with mini-implants in clear aligner treatment. The objective of this study was to evaluate the effectiveness of maxillary anterior teeth intrusion with different intrusion modes, aiming to provide references for precise and safe intrusion movements in clinical practice. METHODS: Cone-beam computed tomography and intraoral optical scanning data of a patient were collected. Finite element models of the maxilla, maxillary dentition, periodontal ligaments (PDLs), clear aligner (CA), attachments, and mini-implants were established. Different intrusion modes of the maxillary anterior teeth were simulated by changing the mini-implant site (between central incisors, between central and lateral incisor, between lateral incisor and canine), loading site (between central incisors, on central incisor, between central and lateral incisor, between lateral incisor and canine), and loading mode (labial loading and labiolingual loading). Ten conditions were generated and intrusive forces of 100 g were applied totally. Then displacement tendency of the maxillary anterior teeth and CA, and stress of the PDLs were analyzed. RESULTS: For the central incisor under condition L14 and for the canine under conditions L11, L13, L23, and L33, the intrusion amount was negative. Under other conditions, the intrusion amount was positive. The labiolingual angulation of maxillary anterior teeth exhibited positive changes under all conditions, with greater changes under linguoincisal loading. The mesiodistal angulation of canine exhibited positive changes under labial loading, while negative changes under linguoincisal loading except for condition L14. CONCLUSIONS: The intrusion amount, labiolingual and mesiodistal angulations of the maxillary anterior teeth were affected by the mini-implant site, loading site, and loading mode. Labial and linguoincisal loading may have opposite effects on the intrusion amount of maxillary anterior teeth and the mesiodistal angulation of canine. The labiolingual angulation of the maxillary incisors would increase under all intrusion modes, with greater increases under linguoincisal loading.

A biomechanical investigation of miniscrews placed on a mandible for temporary anchorage; a patient-specific finite element analysis.

Miniscrews are temporary skeletal anchorage devices that are widely used in orthodontic treatment, and their success depends on the placement area, angle, technique, and screw dimensions. This study aimed to investigate the effects of miniscrew lengths, insertion angles, and force directions on a mandible model consisting of teeth, cortical and cancellous bones. One Dental Volumetric Tomography (DVT) scan from a patient who had miniscrews were used for mandibular bone modeling to perform finite element analysis. The model variables included miniscrew lengths (6, 8, and 10 mm), insertion angles (-15°, 45°, 60°, and 90°), and force directions (30°, 45°, and 60°). The minimum and maximum stresses were calculated as 18.61 and 37.11 MPa at 6 mm and 10 mm, respectively. According to the insertion angles, the lowest stress was observed at 60°, while the highest stress was found at 15° in the ventral direction. At force directions, the lowest stress was at 60°, and the highest stress was at 45°. However, there were no significant differences in insertion angles and force directions. A statistically significant difference was determined in miniscrew length. As a result, the best result was calculated to be 6 mm inserted at a 60° angle, which could induce the lowest stress. Increasing the miniscrew length will increase the stress on the mandible. In addition, because of the higher force direction, stress decreases with shorter power arms.

Effect of Different Mini Implant Assisted Rapid Palatal Expansion (MARPE) Designs on Maxillary Protraction in Skeletal Class III malocclusion: An FEM Study.

Background: Four different designs of mini-implant-assisted rapid palatal expansion (MARPE) and protraction in nasomaxillary complex and mid-palatal sutures in late adolescent skeletal Class III malocclusion were compared using a three-dimensional finite element analysis. Methods: A finite element model of skull and related sutures was constructed using the computed tomography scan of a 16-year-old female patient with skeletal Class III and ANB of -2°. Four appliance designs: Type I: MARPE with palatal force, Type II: MARPE with buccal force, Type III: Hybrid hyrax with palatal force, and Type IV: Hybrid hyrax with buccal force. Protraction vectors were and analyzed using Ansys software (ANSYS 2021 R2). The displacement pattern of the nasomaxillary structures and the stress distribution in the sutures were examined in all four appliance designs. Results: All the appliance designs resulted in a forward movement of the maxilla, while Type I and III, which used palatal protraction force, caused the greatest forward displacement. In Type I, II, and III, along with forward movement, a clockwise rotation of maxilla was observed, while in Type IV, an anticlockwise rotation of maxilla was observed. Type I, II, and III resulted in higher stress distribution around the superior structures, while Type IV resulted in less stress distribution around the superior structures of maxilla. Conclusion: The forward displacement was enhanced when palatal plates were used to protract the maxilla. The effective appliance design for skeletal class III with open bite case was Type I, II, and III and Type IV for deep bite cases.

Global scholarly output on orthodontic temporary anchorage devices (TADs): A silver jublee scientometric analysis.

OBJECTIVES: This study aimed to analyze the global scholarly production of articles related to temporary anchorage devices (TADs) from 1998-2023 in peer-reviewed dental journals indexed in the Web of Science. MATERIALS AND METHODS: A database of TADs-related articles was created via a Web of Sciences structured search. The bibliometric characteristics of the studies, including the number of citations, publication year, journal title, journal impact factor (IF), authorship, contributing institutions and countries, thematic field, and study design, were extracted. Keyword co-occurrence network analyses and the correlation between the number of citations and the article age, journal IF, and journal quartile of each article were performed. RESULTS: The top 50 cited articles were published from 1999-2016, and the total number of citations ranged from 82-602, with 160.36 citations/paper on average. Most of the articles originated from Japan (n = 12), with the most remarkable contributions from Nihon and Okayama Universities, Japan (n = 5, each). The American Journal of Orthodontics and Dentofacial Orthopedics had the most cited articles, with 196.57 citations/paper on average. A significant positive correlation occurred between the number of citations and publication age (rho = 0.392, P = 0.005). CONCLUSION: Our scientometric analysis reported the characteristics of TADs-related articles published over 25 years. Most highly-cited articles were published between 2005 and 2008. The positive correlation between articles' publication date and the number of citations might impact the top 50 within the next 5-10 years.

Bilateral distalization of maxillary first molars in a group of adult patients after extraction of maxillary second molars using infra-zygomatic mini-implants: A prospective clinical trial.

BACKGROUND: It is now possible to predictably distalize maxillary first molars in nongrowing patients with the infra-zygomatic gear distalizer and to improve malocclusions without having to extract the premolars and regardless of the patient's compliance. The purpose of this study was to investigate the amount and rate of distal movement of the maxillary first molars using our proposed appliance after extraction of maxillary second molars. METHODS: Ten nongrowing female patients successfully treated with our proposed appliance were the subjects of this study. The amount, rate, and type of distalization, were analyzed through upper jaw cone beam computed tomography (pre- and post-treatment) and scanned casts taken on a monthly interval. RESULTS: The average amount of distalization of the maxillary first molars was 4.03 mm at the crown level and 2.88 mm at the root level. The rate of distalization had an average of 0.61 mm per month with a maximum of 0.79 mm in the first month because of the regional acceleratory phenomena after extracting the maxillary second molar. CONCLUSIONS: The maxillary first molars were distalized in a significant manner and all patients reached a Class I relation within an average duration of 6.4 months. The proposed appliance proved to be a viable noncompliance modality to distalize maxillary first molars correcting maxillary Class II malocclusions characterized by maxillary protrusion or maxillary incisor crowding.

Effect of Surface Topography on the Primary Stability of Miniscrew Implants in Orthodontics-A Systematic Review and Meta-Analysis.

This present study has the purpose of determining how surface topography of implants affects the initial stability of miniscrew implants (MSIs). Electronic databases like PubMed Central, Scopus, Web of Science, Embase, and Cochrane Library, as well as reference lists, were thoroughly searched up until September 2022. Clinical trials involving individuals who got anchorage through mini-implants, along with information on categories of mini-implants dimension, shape, thread design, and insertion site, were required as part of the eligibility criteria. Primary and secondary stability were also assessed. We carried out selection process for the study, extraction of data, quality assessment, and a meta-analysis. The qualitative synthesis included 10 papers: three randomized, four prospective, and four retrospective clinical investigations. The results of this meta-analysis demonstrate that the clinical state of MIs is controlled by their geometrical surface qualities, which are also influenced by their shape and thread design. According to the evidence this meta-analysis produced, this circumstance exists. The duration of the follow-up period and MI success rates did not correlate with one another.

Protraction of Mandibular Second Molar for Substitution of Adjacent Missing First Molar With a Mini-Implant-Anchored Albert Loop Appliance.

Protraction of mandibular posterior teeth into edentulous regions is challenging in clinical practice. This case demonstrated a minor tooth movement of a mandibular second molar to substitute its adjacent missing first molar in a 15-year-old female. An efficient bodily movement of the mandibular second molar was achieved through a mini-implant-anchored protraction loop appliance. With this carefully designed biomechanical system, over 10-mm molar protraction was accomplished within 14 months without mesial or lingual tipping. The adjacent third molar erupted spontaneously during the protraction process and drafted mesially. Through brackets and segmented archwire after the protraction, the second and third molars were successfully protracted and good buccal interdigitation was achieved. The combination of the Albert protraction loop and mini-implant allows for more efficient protraction of the mandibular molars, avoiding mesial tipping and lingual rotation of the molars.

Evaluation of Optimal Insertion Sites and Angles for Orthodontic Mini-Implants at the Anterior Nasal Spine Region Based on Cone-Beam Computed Tomography.

BACKGROUND: To infer the optimal angulation and height level of mini-implant insertion in the anterior nasal spine (ANS) region from alveolar bone depth (BD) and labial cortical bone thickness (CBT) through cone-beam computed tomography (CBCT), the influences of sex, age, and growth pattern on BD, CBT, and the starting point of the ANS were examined. MATERIAL AND METHODS: BD and CBT were measured on CBCT median sagittal images at specific angles (0, 15, 30, 45, and 60 degrees) to simulate the angulation of insertion. The height level of the first axial image with obvious bone ridge was recorded as the start of ANS. RESULTS: The average height of ANS start was 9.42 mm from the alveolar bone crest between the central incisors. The variations in height level and insertion angle combined, or either of them individually, significantly influenced BD and CBT, demonstrating overall decreasing trends (p < 0.001). BD was not influenced by sex, age, or growth pattern (p > 0.05). However, CBT was found to be correlated with sex and growth pattern, while the height level of ANS start was associated only with growth pattern, particularly in hypodivergent patients (p < 0.05). CONCLUSION: The recommended insertion height level is 14-16 mm from the alveolar bone crest and the recommended angulation is 30-45°. An innovative inequity in the relationship between a certain height level and the insertion angulation is proposed.

Orthodontic camouflage treatment for a patient with bilateral cleft lip and palate, bilateral crossbite, and microdontic maxillary lateral incisors.

Cleft lip and palate is a congenital craniofacial anomaly that affects the lip and oral cavity. The management and orthodontic treatment of this anomaly is important but challenging. This article reports the successful treatment of a patient with bilateral cleft lip and palate, Class III malocclusion, bilateral crossbite, crowding and microdontic maxillary lateral incisors. One mandible incisor was extracted, and three miniscrew anchorages were utilized to distalize the maxillary left dental arch and retract the mandibular arch. After treatment, ideal occlusion and a better profile were established, and long-term stability was confirmed by a 4-year follow-up. This article represents a successful attempt of orthodontic camouflage treatment of severe dentofacial discrepancy, as an important part of the series treatment of cleft lip and palate, to provide some insight into the clinical field.

Comparison between effects of mini-implant anchorage and face-bow anchorage in orthodontics for children.

To study the values of mini-implant anchorage in orthodontics for children in the mixed dentition stage, 78 children in the mixed dentition stage who had accepted orthodontic treatment in our hospital from January 2020 to January 2021 were enrolled into this study. All children were treated with straight-wire appliance. According to their anchorages, children were divided into observation group and control group based on the random number table. Children in the control group used face-bow to control the anchorages and children in the observation group used mini-implants to control the anchorages. After treatment, the upper central incisor convex distance difference, inclination angle of the upper central incisor, displacement of the molar, gingival health, masticatory function, treatment effect and adverse reaction rate of children in two groups were compared. One year after treatment, compared with children in the control group, children in the observation group had smaller the upper central incisor convex distance difference, inclination angle of the upper central incisor, displacement of the molar, small scores of plaque index (PLI), bleeding index (BI) and gingival index (GI), stronger biting force and higher masticatory efficiency, lower adverse reaction rate during treatment, better treatment effect, higher satisfaction of orthodontic treatment. And differences of all the above indexes were statistically significant (p < 0.05). Mini-implant anchorages have good stability and directive force, and have certain values in orthodontics for children in the mixed dentition stage.

A finite element analysis of stress distribution with various directions of intermaxillary fixation using orthodontic mini-implants and elastics following mandibular advancement with a bilateral sagittal split ramus osteotomy.

OBJECTIVE: This finite element analysis (FEA) aimed to assess the stress distribution in the mandible and fixation system with various directions of the intermaxillary fixation (IMF) using mini-implants (MIs) and elastics following mandibular advancement with a bilateral sagittal split ramus osteotomy (BSSRO). MATERIALS AND METHODS: A total of nine mandibular advancement models were set according to the position of the MIs (1.6 mm in diameter, 8 mm in length) and direction of the IMF elastics (1/4 inch, 5 oz). Major and minor principal stresses in the cortical and cancellous bones, von Mises stresses in the fixation system (miniplate and monocortical screws), and bending angles of the miniplate were analysed. RESULTS: Compressive and tensile stress distributions in the mandible and von Mises stress distributions in the fixation system were greater in models with a Class III IMF elastic direction and a higher IMF elastic force than in models with a Class II IMF elastic direction and a lower IMF elastic force. The bending angle of the miniplate was negligible. CONCLUSIONS: Stress distributions in the bone and fixation system varied depending on the direction, amount of force, and position of IMF elastics and MIs. Conclusively, IMF elastics in the Class II direction with minimal load in the area close to the osteotomy site should be recommended.

The success rate of mini-screws for incisors intrusion and patient age, gender, and insertion angle in the maxilla using CBCT and implant-guided surgery. A split-mouth, randomized control trail.

BACKGROUND AND OBJECTIVES: The intrusion of anterior teeth is a routine procedure in orthodontics, which has been performed efficiently with the help of mini-screws in the anterior region, especially the upper maxilla. This study aimed to investigate the effect of insertion angle and sociodemographic features on the success rate of mini-screws at the anterior maxillary region. MATERIALS AND METHODS: Twenty-nine patients (18 Females and 11 Males) aged 18-40 years old were involved in the current study. A split-mouth design was carried out in which recruited patients needed bilateral anterior screws at the labial bone in the region of the incisor for the intrusion of upper anterior incisor teeth as part of their orthodontic treatment with a fixed appliance (upper right side received 90-degree insertion angle mini-screw and 45° for left side) using a surgical guide fabricated from patients CBCT and intraoral scans. The mini-screws were inserted at the attached gingiva bilaterally to achieve intrusion of upper anterior teeth with a power chain ligated from the main archwire to the anterior min-implants. The patient was recalled monthly for orthodontic appliance activation and screw assessment for 6 months. The intrusion force was 15 g on each side. RESULTS: The results of the study showed that screw stability was higher in the male group than the female group at the 6th monthly follow-up visit with a statistically significant difference between both genders (P = .044). Concerning insertion angle, results showed a statistically significant difference between 45° and 90° as an insertion angle with a P-value <.01 in most of the follow-up months. CONCLUSION: This study found that male patients with mini-screws inserted at 90° showed greater screw stability over time.

Three-dimensional volumetric evaluation of root resorption in maxillary anteriors following en-masse retraction with varying force vectors - a randomized control trial.

BACKGROUND: Root resorption in orthodontics is associated with direction and magnitude of force application as primary etiological factors. Well-controlled trials that utilize three-dimensional segmentation to detect volumetric changes in tooth structure are required to assess the quantitative nature of root resorption. OBJECTIVE: To assess the severity of root resorption (RR) during retraction of maxillary anteriors with three different force vectors (with and without skeletal anchorage) via cone-beam computed tomography (CBCT) superimpositions. TRIAL DESIGN: Three-arm parallel randomized clinical trial (RCT). MATERIALS AND METHODS: Forty-two (16 males, 26 females) patients, (17-28 years), in permanent dentition with bimaxillary protrusion were randomly allocated to three groups of 14 patients each using block randomization (1:1:1 ratio) and allocation concealment. En-masse anterior retraction post first premolar extractions was carried out with modified force vectors in the three groups based on anchorage type [Molar, Mini-implant and Infrazygomatic crest (IZC) bone screws]. Volumetric root loss and linear dimensional changes were blindly assessed on initial (T0) and final (T1, end of space closure) CBCT scans. Normality distribution of values was done using Shapiro-Wilk's test. ANOVA and Post-hoc Tukey HSD test were done to compare measurements between groups at significance levels (P < .05). RESULTS: Forty patients were analysed (14, 14, and 12 in three groups). Significant volumetric loss was noted in all groups. Central incisors demonstrated a significant reduction in IZC group (81.5 ± 21.1 mm3 ) compared to conventional (50.1 ± 26.5 mm3 ) and mini-implant groups (76.1 ± 27.6 mm3 ). Canines demonstrated a significant reduction in mini-implant group (108.9 ± 33.9 mm3 ) compared to conventional (68.8 ± 42.5 mm3 ) and IZC groups (103.1 ± 29.1 mm3 ). Regarding linear parameters, central incisors and canines revealed significant root length reduction in both skeletal anchorage groups. Lateral incisors showed no significant changes between groups. CONCLUSIONS: Intrusive force vectors generated during skeletally anchored retraction can predispose anteriors to an increased risk of resorption. Greater loss of root volume was noted in the centrals and canines when retracted with skeletal anchorage. LIMITATIONS: Small sample size and variations during CBCT acquisition. HARMS: Low-dose CBCT scans were taken at T0 and T1 treatment intervals.

Comparison of the effectiveness of piezocision-aided canine retraction augmented with micro-osteoperforation: a randomized controlled trial.

OBJECTIVE: To evaluate the effectiveness of micro-osteoperforation (MOP) on the rate of piezocision-aided canine retraction (CR). MATERIALS AND METHODS: The split-mouth study included 25 participants at the stage of commencing CR. The participants received flapless piezocision bilaterally at T0 (0 months) and MOP only on one side at T3 (3 months). The quadrant that received MOP at T3 served as the intervention, whereas the other quadrant served as the control. The primary outcome was the rate of CR, assessed using digital models. The angular change (AC) of the canine and the change in the buccal cortical bone thickness (BCBT) from before to after CR were also assessed using cone beam computed tomography. RESULTS: The rate of CR was 0.82 ± 0.39 mm/month in the control quadrant vs 0.75 ± 0.44 mm/month in the intervention quadrant (P > .05). The AC of the canine was 2.00° ± 0.88° in the control quadrant vs 1.98° ± 0.86° in the intervention quadrant (P > .05). The crestal bone gain was 0.50 mm in the control quadrant vs 0.28 mm of bone loss in the intervention quadrant. The bone thickness at a 3-mm height was increased by 0.11 mm in the control quadrant vs a 0.29-mm decrease in the intervention quadrant. The bone thickness at a 6-mm height was decreased by 0.12 mm in the control quadrant vs a 0.15-mm decrease in the intervention quadrant. However, none of the changes or group differences in bone height or thickness were statistically significant (P > .05). CONCLUSIONS: The periodic activation of a piezocision-aided CR site using MOP had no significant positive effect on the rate of CR, angulation of the canine, or changes in BCBT.

A Retrospective Histological Study on Palatal and Gingival Mucosa Changes during a Rapid Palatal Expansion Procedure.

The most common inflammatory reactions in the oral mucosa are found at the gingival level. The treatment of these inflammations requires, first of all, the removal of the causative factor; often, this maneuver is sufficient. The aim of this retrospective study was to evaluate clinical and histopathological changes that occur in terms of gingival and palatal mucosa enlargement during palatal expansion treatment and their evolution during treatment. Twenty-five (n = 25) research participants, aged between thirteen and twenty-six years old, were examined in this retrospective study. At the end of the treatment, fragments of tissue from the affected level were obtained via incisional biopsy and sent to the histopathology laboratory for a specialized examination. The changes identified were specific to mechanical traumatic injuries, thus excluding hyperplasia from other etiologies (infectious, tumoral, or non-mechanical traumatic). The examined fragments showed hyperplasia. The histopathological examination revealed the mechanical character of the lesion, strengthening the causal relationship between the insertion of the expander and the occurrence of hyperplasia of the palatal mucosa. The type of palatal expander influenced the degree of inflammation, with the severity of hyperplasia being more pronounced in the case of mini-implant-anchored rapid palatal expander (MARPE) usage than in the case of tooth-borne rapid palatal expander (RPE) usage. The analysis of the distance between the expander and the palatal mucosa did not provide conclusive results; the incidence and severity of the reaction were variable in patients with the same distance between the expander and the palatal or gingival mucosa.

Accuracy of Palatal Orthodontic Mini-Implants Placed Using Fully Digital Planned Insertion Guides: A Cadaver Study.

Digital workflows have become integral in orthodontic diagnosis and therapy, reducing risk factors and chair time with one-visit protocols. This study assessed the transfer accuracy of fully digital planned insertion guides for orthodontic mini-implants (OMIs) compared with freehanded insertion. Cone-beam computed tomography (CBCT) datasets and intraoral surface scans of 32 cadaver maxillae were used to place 64 miniscrews in the anterior palate. Three groups were formed, two using printed insertion guides (A and B) and one with freehand insertion (C). Group A used commercially available customized surgical templates and Group B in-house planned and fabricated insertion guides. Postoperative CBCT datasets were superimposed with the planning model, and accuracy measurements were performed using orthodontic software. Statistical differences were found for transverse angular deviations (4.81° in A vs. 12.66° in B and 5.02° in C, p = 0.003) and sagittal angular deviations (2.26° in A vs. 2.20° in B and 5.34° in C, p = 0.007). However, accurate insertion depth was not achieved in either guide group; Group A insertion was too shallow (-0.17 mm), whereas Group B insertion was deeper (+0.65 mm) than planned. Outsourcing the planning and fabrication of computer-aided design and computer-aided manufacturing insertion guides may be beneficial for certain indications; particularly, in this study, commercial templates demonstrated superior accuracy than our in-house-fabricated insertion guides.

The short- and long-term changes of upper airway and alar in nongrowing patients treated with Mini-Implant Assisted Rapid Palatal Expansion (MARPE): a systematic review and meta-analysis.

OBJECTIVE: This study aims to assess the short- and long-term changes in the upper airway and alar width after mini-implant -assisted rapid palatal expansion (MARPE) in nongrowing patients. METHODS: Five electronic databases (PubMed, Scopus, Embase, Web of Science, and Cochrane Library) were searched up to 2 August, 2023 based on the PICOS principles. The main outcomes were classified into three groups: 1) nasal cavity changes, 2) upper airway changes and 3) alar changes. The mean difference (MD) and 95% confidence intervals (CI) were used to assess these changes. Heterogeneity tests, subgroup analyses, sensitivity analyses, and publication bias were also analyzed. RESULT: Overall, 22 articles were included for data analysis. Nasal cavity width (WMD: 2.05 mm; 95% CI: 1.10, 3.00) and nasal floor width (WMD: 2.13 mm; 95% CI: 1.16, 3.11) increased significantly. While palatopharyngeal volume (WMD: 0.29 cm3, 95% CI: -0.44, 1.01), glossopharyngeal volume (WMD: 0.30 cm3, 95% CI: -0.29, 0.89) and hypopharyngeal volume (WMD: -0.90 cm3; 95% CI: -1.86, 0.06) remained unchanged, nasal cavity volume (WMD: 1.24 cm3, 95% CI: 0.68, 1.81), nasopharyngeal volume (MD: 0.75 cm3, 95% CI: 0.44, 1.06), oropharyngeal volume (WMD: 0.61 cm3, 95% CI: 0.35, 0.87), and total volume of the upper airway (WMD: 1.67 cm3, 95% CI: 0.68, 2.66) increased significantly. Alar width (WMD: 1.47 mm; 95% CI: 0.40, 2.55) and alar base width (WMD: 1.54 mm; 95% CI: 1.21, 1.87) also increased. CONCLUSION: MARPE can increase nasal cavity width, nasal cavity volume, nasopharyngeal volume and oropharyngeal volume for nongrowing patients, but has no significant effect on hypopharyngeal volume. In addition, the alar width also increased. However, the studies included in this meta-analysis were mainly retrospective, nonrandomized and small in number, so the findings should be interpreted with caution and high-quality RCTs need to be studied.

The effect of different orthodontic mini-implant brands and geometry on primary stability (an in vitro study).

Background: In orthodontic procedures, mini-implants are routinely used as temporary anchorage devices. Early failure is primarily attributed to a variety of issues, which are mostly connected to the quality and geometry of the screw that lead to insufficient primary stability. Objectives: To evaluate the primary stability of different sizes and brands of orthodontic mini-implants by optimizing the insertion torque value (ITV) and to clear out which one has the greatest primary stability among the most widely used mini-implants by orthodontists. Methods: Eighty-two self-drilling mini-implants from three different brands with different sizes were used (Optimus Ortho System (Osteonic made in Korea), Smart anchor (GNI made in Korea) (1.4 × 6, 1.6 × 8 and 1.8 × 10mm) and Morelli (made in Brazil) (1.5 × 6, 1.5 × 8 and 1.5 × 10mm), made from (Ti 6Al 4V). All were drilled at a 60° angle on Sixty artificial bone blocks made from polyurethane foam with a digital torque meter device (Orthonia, Jeil made in Korea), pullout strength (tensile force) was measured with a universal testing machine to find out the best brand and size in the mean of primary stability. Data were analyzed using SPSS Version 25 and JMP Pro Version 16 software using the One-way ANOVA test, the Post hoc and Tukey HCD tests. Results: There were significant differences between the pullout strength of different sizes for the GNI and OSTEONIC brands, while for the MORELLI brand there were no significant differences between the three different sizes considering ITV (10Ncm) whereas for ITV (20Ncm) there was a significant difference between the different sizes for the pullout of all three brands. GNI was the best brand for all the selected sizes with ITV (10Ncm) and size 1.4 × 6 for ITV (20Ncm), whereas OSTEONIC sizes 1.6 × 8 and 1.8 × 10 were the best for ITV (20Ncm) in term of primary stability. Conclusion: GNI screws were demonstrated higher primary among the three widely used brands followed by OSTEONIC for size 1.6 × 8 and 1.8 × 10 while MORELLI was the least resistant to dislodgement for the two torque insertion values 10 N/cm and 20 N/cm.

Comparison of primary stability of used and unused self-tapping and self-drilling orthodontic mini-implants.

BACKGROUND: Skeletal anchorage has been the subject of study for many years. Recently, orthodontic mini-implants (MIs) were described as effective tools for anchorage and were named temporary anchorage devices (TADs). The success of MIs depends on their primary stability, which is defined as the lack of mobility in the bone after implant insertion, and the relevant factors affecting primary stability. OBJECTIVES: This study aimed to compare the primary stability of used self-drilling (SD) and self-tapping (ST) MIs with unused ones by performing the insertion torque measurement, Periotest and pull-out test. MATERIAL AND METHODS: Forty-six used (23 ST, 23 SD) and 46 unused (23 ST, 23 SD) MIs (1.5 mm × 8 mm) were inserted into a synthetic bone with the use of a digital screwdriver. Maximum insertion torque (MIT) values were recorded during the placement of MIs, and then Periotest measurements were made. Following the MIT and Periotest measurements, pull-out tests were performed on all MIs. RESULTS: The median MIT values (Ncm) of the MIs were as follows: used ST: 17.3, unused ST: 18.9, used SD: 24.1, unused SD: 25.2. The median values obtained after the Periotest were (±): used ST: 0, unused ST: -1, used SD: -3, unused SD: -3. Median pull-out values (N) were: used ST: 148.12, unused ST: 168.12, used SD: 173.12, unused SD: 203.20. Statistically, MIT and pull-out values of the used ST and SD implants were significantly lower compared to those of the unused ST and SD implants (p < 0.05). CONCLUSIONS: Used orthodontic MIs showed poor performance compared with unused implants when they were inserted again in the in vitro conditions.

Postgraduate orthodontic education: An international perspective on content and satisfaction levels.

BACKGROUND: There is significant international variation in the postgraduate orthodontic training. The aim of this study was to obtain information relating to the design, content, and delivery of formal postgraduate orthodontic training internationally. Moreover, we aimed to evaluate the perception of orthodontists towards their training as well as identifying factors associated with an improved level of satisfaction. METHODS: A 42-question survey was sent to orthodontists worldwide via SurveyMonkey. The survey was circulated on orthodontic Facebook groups and through other digital channels including Instagram. RESULTS: A total of 168 respondents completed all sections of the questionnaire. The vast majority believed programme length was appropriate (n = 150; 89%). Most respondents were confident with their research skills and in their ability to diagnose and treatment plan. Social media was frequently accessed by the respondents for the purposes of orthodontic education (n = 83; 49%). A high proportion (n = 70; 42%) did not treat any clear aligner cases during postgraduate training with many having experience using InvisalignTM only. The majority of respondents across the regions had training in buccal miniscrew insertions. Exposure to three-dimensional printing during residency was limited. CONCLUSIONS: The study offers an overview of the structure, content, and modes of delivery in orthodontic postgraduate training internationally. While satisfaction levels are good, there is a disparity in terms of exposure to certain techniques internationally. Further training in the modern diagnostic approaches and mechanics may improve satisfaction with postgraduate training.