Efficacy of orthodontic mini implants for en masse retraction in the maxilla: a systematic review and meta-analysis

Accelerated corrosion of 316L stainless steel in a simulated oral environment via extracellular electron transfer and acid metabolites of subgingival microbiota

316L stainless steel (SS) is widely applied as microimplant anchorage (MIA) due to its excellent mechanical properties. However, the risk that the oral microorganisms can corrode 316L SS is fully neglected. Microbiologically influenced corrosion (MIC) of 316L SS is essential to the health and safety of all patients because the accelerated corrosion caused by the oral microbiota can trigger the release of Cr and Ni ions. This study investigated the corrosion behavior and mechanism of subgingival microbiota on 316L SS by 16S rRNA and metagenome sequencing, electrochemical measurements, and surface characterization techniques. Multispecies biofilms were formed by the oral subgingival microbiota in the simulated oral anaerobic environment on 316L SS surfaces, significantly accelerating the corrosion in the form of pitting. The microbiota samples collected from the subjects differed in biofilm compositions, corrosion behaviors, and mechanisms. The oral subgingival microbiota contributed to the accelerated corrosion of 316L SS via acidic metabolites and extracellular electron transfer. Our findings provide a new insight into the underlying mechanisms of oral microbial corrosion and guide the design of oral microbial corrosion-resistant materials.

The current overview of the devices of temporary anchorage placed on the palatal bone: CBCT study

Temporary anchorage devices (TADs) are frequently applied to different anatomic areas with different protocols to increase skeletal effects and anchorage in orthodontic treatment planning. It has been reported in many literatures that primary stability for orthodontic TADs is significant for long-term survival rate. For this reason, different areas of the palatal region, which has many indications, have been widely used in the studies. In this evaluation where bone quality and thickness are important, density, bone thickness, and fractal dimension (FD) on cone beam computed tomography (CBCT) will provide more predictable clinical results. The aim of this study was to evaluate bone thickness, density, and FD in the palatal region of the first, and second premolars, and first molars. There was a remarkable difference (p < 0.05) between the parameters of FD, thickness and density of bone in the identified areas in the palatal region. In terms of thickness and FD, the 1st premolar region had significantly higher values than the other regions (p < 0.05). In terms of density, the values in the right 1st molar and right 1st premolar regions were significantly higher (p < 0.05). The 1st premolar region is an ideal site for placement of palatal TADs. CBCT-assisted preliminary evaluation of FD value, bone density, and thickness may increase clinical success when selecting the location of TADs to be applied to the palatal bone.

Comparison of two treatment protocols for intrusion and retraction of maxillary anterior teeth using mini-implants : A prospective clinical trial

OBJECTIVE

The primary objective of this study was to compare the magnitude of incisor intrusion and retraction between two different treatment protocols and the secondary objective was to evaluate overall treatment effects.

MATERIALS AND METHODS

Thirty-four patients with proclined upper anterior teeth, increased overbite, and incisal show were randomly assigned to two treatment groups (G1 and G2). Upper first premolar extractions were performed in all cases. In G1, space closure was performed with conventional straight-wire friction mechanics with NiTi (nickel titanium) coil springs placed on 0.019″ × 0.025″ stainless steel wires in a 0.022 slot system with an additional intrusive force via a midline mini-implant. In G2, NiTi coil springs were placed from buccal mini-implants placed onto 0.016″ × 0.022″ SS wires in a 0.022 slot system bilaterally. Lateral cephalograms and study models taken at the beginning and at the end of 6 months of treatment were assessed.

RESULTS

Both groups showed a statistically significant mild maxillary incisor intrusion, reduction in overjet, overbite, incisal show and a reduction in lower anterior facial height. There was a mild intrusion of the maxillary first permanent molar in G2 (not significant). Mesial movement of the maxillary first permanent molar was noted in G1 but distal movement occurred in G2. Constriction of the entire maxillary arch was noted in G1, whereas constriction was seen in the molar region only in G2. Root resorption was noticed in both groups.

CONCLUSION

Both groups produced comparable results. Except for molar control, all the results obtained were comparable between the two mechanics. Application of an intrusive force in the midline may be beneficial in patients treated with conventional straight-wire mechanics to treat increased overbite when anchorage requirement is not high.

Differences in the effects of orthodontic treatment on airway-craniocervical functional environment in adult and adolescent patients with skeletal class II high-angle: a retrospective pilot study

INTRODUCTION

This retrospective cohort study aimed to compare the change in upper airway and craniocervical posture after orthodontic treatment between adolescent and adult patients with Class II high-angle malocclusion.

METHODS

A total of 12 adolescent (mean ± standard deviation age = 13.0 ± 2.0 years) and 12 adult patients with Class II high-angle malocclusion (mean ± standard deviation age = 23.7 ± 6.4 years) were selected in this study. The lateral cephalograms and cone beam computed tomography images of adolescent and adult patients were taken before and after treatment, which can be employed to evaluate the variables of craniofacial morphology, upper airway, and craniocervical posture through paired t tests, respectively. An independent sample t test was performed to observe the differences between two groups after orthodontic intervention. For adults and adolescents, the correlation between craniofacial morphology, upper airway, and craniocervical posture was determined through Pearson correlation analysis.

RESULTS

In all subjects, the improvements in vertical and sagittal facial morphology after treatment were observed. Anterior and inferior movements of the hyoid bone, an increase of upper airway dimension, posterior tipping of the head and a reduction of cervical inclination in the lower and middle segments post-treatment were identified in adolescence (P < 0.05). Adults displayed anterior movements of the hyoid bone, whereas no significant difference was observed in upper airway dimension and craniocervical posture (P < 0.05). Notable differences were identified in the change of hyoid position and airway volume between two groups (P > 0.05). Mandibular plane inclination, growth pattern, occlusal plane inclination, and chin position were all significantly correlated with craniocervical posture in adolescent patients. Besides, the mandibular growth pattern and chin position in adult patients were significantly correlated with craniocervical posture (P < 0.05).

CONCLUSIONS

Orthodontic treatment is capable of enhancing the facial profile of patients with skeletal class II high-angle while improving their upper airway morphology and craniocervical posture, where adolescents and adults differ substantially in that the former exhibit a more favorable alteration in the airway-craniocervical functional environment.

Skeletal Anchorage Augmentation in Extraction/Nonextraction Orthodontic Treatment: A Randomized Clinical Study

AIM

To evaluate and compare skeletal, dental, and soft tissue parameters by therapeutic extraction of first premolar and nonextraction distalization of maxillary and mandibular arches in bimaxillary proclination using the skeletal anchorage system.

MATERIALS AND METHODS

About 40 orthodontic patients undergoing extraction or nonextraction treatment are enrolled in a randomized clinical trial. Participants are randomly assigned to either the extraction or nonextraction group and receive treatment augmented with skeletal anchorage. Mini implants were placed in the extraction group for retraction and infra-zygomatic crest (IZC) and buccal shelf screws were placed in the nonextraction group for distalization.

OBSERVATIONS AND RESULTS

Comparison between the ages of the patients among both Groups showed no significant difference. A significant difference is observed in dental and soft tissue parameters before and after the treatment in group A, whereas skeletal parameters also showed significant changes along with dental and soft tissue parameters in group B.

CONCLUSION

There is a significant change in the position of incisors by retraction and facial profile improves gradually in group A while for group B, a marked change in lower facial height was even seen. On comparing both the groups, a highly significant difference can be seen with respect to the amount of incisor retraction and change in molar inclination. The time taken for retraction of incisors is less in comparison to distalization.

CLINICAL SIGNIFICANCE

With this, we can easily avoid premolar extraction, and in cases of impacted third molars distalization as when indicated can be helpful as a part of the nonextraction treatment plan.

Systematic review and network meta-analysis of the accuracy of the orthodontic mini-implants placed in the inter-radicular space by image-guided-based techniques

OBJECTIVE

The aim of the present systematic review and network meta-analysis (NMA) is to analyze the accuracy of image-guided-based orthodontic mini-implants placement techniques in the inter-radicular space.

METHODS

The study was conducted under the PRISMA recommendations. Three databases were searched up to July 2022. In vitro randomized experimental trials (RETs) including static computer-aided implant surgery (s-CAIS), mixed reality (MR), soft tissue static computer-aided implant surgery (ST s-CAIS) and conventional free-hand technique (FHT) for the orthodontic mini-implants placement in the inter-radicular space were selected. The risk of bias was assessed using the Current Research Information System scale. A random effects model was used in the NMA. Direct comparisons were combined with a random effects model in a frequentist NMA to estimate indirect comparisons, and the estimated effect size of the comparisons between techniques were analyzed by difference of means. Inconsistency was assessed with the Q test, with a significance level of p < 0.05, and a net heat plot.

RESULTS

A total of 92 articles was identified, and 8 RETs (8 direct comparisons of 4 techniques) were included in the NMA, which examined 4 orthodontic mini-implants placement techniques: s-CAIS, MR, ST s-CAIS, and FHT. Taking FHT as reference, s-CAIS and ST s-CAIS showed statistically significant coronal and apical deviation. In addition, s-CAIS showed statistically significant angular deviation. However, MR did not show statistically significant differences with respect to FHT, which presented the highest p-score. At the coronal deviation, ST s-CAIS presented the highest P-score (0.862), followed by s-CAIS (0.721). At the apical deviation, s-CAIS presented the highest P-score (0.844), followed by ST s-CAIS (0.791). Finally, at the angular deviation s-CAIS presented again the highest P-score (0.851).

CONCLUSIONS

Within the limitations of this study, it was found that the image-guided-based orthodontic mini-implants placement techniques showed more accuracy than the free-hand conventional placement technique; specially the computer-aided static navigation techniques for the orthodontic mini-implants placed in the inter-radicular space.

Orthodontic camouflage treatment of pseudo-Class III malocclusion on skeletal class III Base complicated with canine impaction treated with temporary anchorage devices: A case report

With conventional mechanics to protract the upper posterior teeth for correcting Class III molar relationships, such as intra-arch mechanics, face mask reverse-pull headgear protraction, and interarch Class III elastics, there are some adverse effects, including diminished patient compliance, the possibility of losing anchorage, and extrusion of upper molars and lower incisors with counterclockwise rotation of the occlusal plane. Protraction force should be directed through the center of resistance of the upper posterior teeth to prevent these side effects.

International investigation on temporary anchorage device use: A survey of orthodontists

BACKGROUND

This study investigates characteristics of temporary anchorage devices (TADs) use by surveying a sample of international orthodontists. Furthermore, the survey investigates the stability, insertion technique, and failure rate of TADs and professionals' experience in residency, and it also attempts to establish guidelines for its use in everyday practice.

METHODS

A 19-question survey was sent to orthodontists worldwide asking opinion-based, case-specific, and placement technique questions regarding TADs. Results were collected from 251 survey respondents. The country/regions of practice and length of time practicing orthodontics were the independent variables.

RESULTS

Survey respondents indicated that most orthodontists rarely or sporadically use TADs. Significant differences were also found for TAD utilization purposes, sizes, and placement techniques among different countries/regions and for failure rates (1 or more of the last 6 TADs placed failed-61.6%). A significant difference was found in how many TADs orthodontists placed in residency versus private practice (56% vs. 15%) in relation to how long they have been practicing, but it did not greatly affect the frequency of use, mechanics, or placement technique.

CONCLUSIONS

The frequency of TAD use is similar in many different countries and among different age groups. Although the collected responses suggested significant differences among respondents from different countries, the variability of results for TAD use worldwide prevent the establishment of clear guidelines.

The Effects of Intrusion of Anterior Teeth by Skeletal Anchorage in Deep Bite Patients; A Systematic Review and Meta-Analysis

Background: Deep bite is known as one of the most common malocclusions, and its treatment and retention are often challenging. The use of mini-screws has been suggested as an ideal method for the intrusion of incisors in deep-bite patients. Still, there are conflicting reports regarding the superiority of this method compared to other common treatments. Aim: The aim of this systematic review and meta-analysis was to evaluate the effects of the intrusion of anterior teeth by skeletal anchorage in deep bite patients. Methods: From the beginning to 15 September 2022, articles on the topic of interest were searched in electronic databases including PubMed, Web of Science, Scopus, EMBASE, and Cochrane’s CENTRAL. Additionally, a hand search for pertinent studies and a search of the grey literature were carried out. After the selection of eligible studies, data extraction was performed using piloted forms. Inverse-variance random-effects meta-analyses were used to combine the outcome measures of dental indices, skeletal cephalometric indices, and dental cephalometric indices. Results: A total of 15 studies (6 RCT; 9 CCT) were included in the systematic review and 14 were used in the meta-analyses. The differences in overbite changes (MD = −0.45, p = 0.04), true incisor intrusion [u1-pp] (MD = −0.62, p = 0.003) and molar extrusion [u6-pp] (MD = −0.40, p = 0.01) were statistically significant and TADs showed better treatment results than other intrusion methods (segmented intrusion arch, utility arch, J hook headgear). No significant differences regarding overjet, molar and incisor tipping, and skeletal indices between mini-screw and other intrusion methods could be found. Conclusion: The use of mini-screws leads to lower overbite and higher true intrusion (about 0.45 and 0.62 mm, respectively) compared to the use of other methods for intruding upper incisors. Furthermore, the effect of TAD on extrusion of molar teeth is less (by 0.4 mm) than other methods.

Three-dimensional evaluation of maxillary tooth movement in extraction patients with three different miniscrew anchorage systems: a randomized controlled trial

OBJECTIVE

To compare the three-dimensional (3-D) movement of maxillary teeth in response to three common miniscrew anchorage systems in extraction patients with maxillary dentoalveolar protrusion.

MATERIALS AND METHODS

The study employed a randomized controlled single-blinded design with three arms. Thirty extraction patients who required maximum anchorage to retract maxillary anterior teeth were included and randomly allocated into three treatment groups: space closure with direct miniscrew anchorage and low crimpable hooks (DL group), indirect miniscrew anchorage and low crimpable hooks (IL group), and direct miniscrew anchorage and high crimpable hooks (DH group). Cone beam computed tomography (CBCT) images of all included patients were obtained immediately before (T0) and after (T1) space closure. The outcomes were 3-D positional changes of maxillary central incisor, lateral incisor, canine, second premolar, and first molar. The repeated measures analysis of variance with post hoc LSD test was used to evaluate differences among groups.

RESULTS

A significant intrusion (- 1.34 mm; 95% CI, - 1.60 mm, 1.08 mm) and buccal (- 6.92°; 95% CI, - 8.67°, - 5.13°) and distal (4.90°; 95% CI, 3.75°, 6.04°) inclination of the maxillary first molars were observed in the DL group, compared to the other two groups. The mesial movement (- 0.40 mm; 95% CI, - 0.83 mm, - 0.03 mm) of the maxillary first molars was found in the IL group, while the DL (0.44 mm; 95% CI, 0.15 mm, 0.73 mm) and IL (0.62 mm; 95% CI, 0.28 mm, 0.96 mm) groups exhibited distal movement. In the DH group, the lingual inclination changes of maxillary central incisor (5.04°; 95% CI, 2.82°, 7.26°) were significantly lower, which is indicative of good lingual root torque control of the maxillary anterior teeth.

CONCLUSION

Three miniscrew anchorage systems produced significantly different 3-D maxillary tooth movement. The maxillary first molars were significantly buccally and distally inclined and intruded in patients using direct miniscrew anchorages with low crimpable hooks. Direct miniscrew anchorages with high crimpable hooks could help to achieve better lingual root torque control of the maxillary incisors. Trial registration The trial was registered at www.chictr.org.cn (ChiCTR1900026960). Registered 27 October 2019.

Effects of Rigid and Nonrigid Connections between the Miniscrew and Anchorage Tooth on Dynamics, Efficacy, and Adverse Effects of Maxillary Second Molar Protraction: A Finite Element Analysis

Introduction

Direct, rigid indirect, and nonrigid indirect absolute anchorages using temporary anchorage devices (TADs, mini-implants/miniscrews) can provide promising opportunities for challenging, yet common, orthodontic tooth movements such as molar protraction. Rigid rectangular wire and ligature wire are the most common methods of attaching a tooth to a miniscrew in indirect anchorages. We aimed to provide a comparison of the rigidity of the connecting wire in terms of stress on the miniscrew, the anchorage loss, and the risk of root resorption using finite element analysis (FEA).

Methods

The maxillary right second molar was protracted into the proximal space at a 150 g load (1) using direct absolute anchorage with a tapered miniscrew implanted between the premolar roots and using indirect absolute anchorage with the second premolar reinforced by the miniscrew through (2) a rigid stainless steel (SS) wire or (3) a nonrigid SS ligature wire (4) at different elastic moduli. Stresses and displacements of 4 models' elements were measured. The risk of external root resorption was evaluated.

Results

Connecting the tooth to the miniscrew using rigid full-size wire (model 2) compared to ligature (model 3) can give better control of the anchorage (using the ligature wire, the anchorage loss is 1.5 times larger than the rectangular wire) and may reduce the risk of root resorption of the anchorage unit. However, the risk of miniscrew failure increases with a rigid connection, although it is still lower than with direct anchorage. The miniscrew stress when using a ligature is approximately 30% of the rigid model using the rectangular wire. The miniscrew stress using the rectangular wire is approximately 82.4% of the miniscrew stress in the direct model. Parametric analysis shows that the higher the elastic modulus of the miniscrew-tooth connecting wire in the indirect anchorage, the less the anchorage loss/palatal rotation of the premolars/and the risk of root resorption of the anchorage teeth and instead the stress on the miniscrew increases.

Conclusions

Direct anchorage (followed by rigid indirect anchorage but not nonrigid) might be recommended when the premolars should not be moved or premolar root resorption is a concern. Miniscrew loosening risk might be the highest in direct anchorage and lowest in nonrigid indirect anchorage (which might be recommended for poor bone densities).

[Efficacy of vertical control by using mini-implant anchorage in maxillary posterior buccal area for Angle class Ⅱ extraction patients]

OBJECTIVE

To investigate the efficacy of vertical control by using conventional mini-implant anchorage in maxillary posterior buccal area for Angle class Ⅱ extraction patients.

METHODS

Twenty-eight Angle class Ⅱ patients [9 males, 19 females, and age (22.6±2.8) years] were selected in this study. All of these patients were treated by using straight wire appliance with 4 premolars extraction and 2 mini-implant anchorage in maxillary posterior buccal area. In this study, the self-control method was used to measure and analyze the lateral radiographs taken before and after orthodontic treatment in each case, the main cephalometric analysis items were related to vertical changes. The digitized lateral radiographs were imported into Dolphin Imaging Software (version 11.5: Dolphin Imaging and Management Solutions, Chatsworth, California, USA), and marked points were traced. Each marked point was confirmed by two orthodontists. The same orthodontist performed measurement on the lateral radiographs over a period of time. All measurement items were required to be measured 3 times, and the average value was taken as the final measurement result.

RESULTS

Analysis of the cephalometric radiographs showed that, for vertical measurements after treatment, the differences of the following measurements were highly statistically significant (P < 0.001): SN-MP decreased by (1.40±1.45) degrees on average, FMA decreased by (1.58±1.32) degrees on average, the back-to-front height ratio (S-Go/N-Me) decreased by 1.42%±1.43% on average, Y-axis angle decreased by (1.03±0.99) degrees on average, face angle increases by (1.37±1.05) degree on average; The following measurements were statistically significant (P < 0.05): the average depression of the upper molars was (0.68±1.40) mm, and the average depression of the upper anterior teeth was (1.07±1.55) mm. The outcomes indicated that there was a certain degree of upper molar depression after the treatment, which produced a certain degree of counterclockwise rotation of the mandibular plane, resulting in a positive effect on the improvement of the profile.

CONCLUSION

The conventional micro-implant anchorage in maxillary posterior buccal area has a certain vertical control ability, and can give rise to a certain counterclockwise rotation of the mandible, which would improve the profile of Angle Class Ⅱ patients.

Which anchorage device is the best during retraction of anterior teeth? An overview of systematic reviews

Objective

To evaluate the available evidence regarding the clinical effectiveness of different types of anchorage devices.

Methods

A comprehensive literature search of different electronic databases was conducted for systematic reviews investigating different anchorage methods published up to April 15, 2021. Any ongoing systematic reviews were searched using PROSPERO, and a grey literature search was undertaken using Google Scholar and OpenGrey. No language restriction was applied. Screening, quality assessment, and data extraction were performed independently by two authors. Information was categorized and narratively synthesized for the key findings from moderate- and high-quality reviews.

Results

Fourteen systematic reviews were included (11 were of moderate/high quality). Skeletal anchorage with miniscrews was associated with less anchorage loss (and sometimes with anchorage gain). Similarly, skeletal anchorage was more effective in retracting anterior teeth and intruding incisors and molars, resulting in minor vertical skeletal changes and improvements in the soft tissue profile. However, insufficient evidence was obtained for the preference of any anchorage method in terms of the duration of treatment, number of appointments, quality of treatment, patient perception, or adverse effects. The effectiveness of skeletal anchorage can be enhanced when directly loaded, used in the mandible rather than the maxilla, used buccally rather than palatally, using dual rather than single miniscrews, used for en-masse retraction, and in adults.

Conclusions

The level of evidence regarding anchorage effectiveness is moderate. Nevertheless, compared to conventional anchorage, skeletal anchorage can be used with more anchorage preservation. Further high-quality randomized clinical trials are required to confirm these findings.

Application of the Digital Workflow in Orofacial Orthopedics and Orthodontics: Printed Appliances with Skeletal Anchorage

As digital workflows are gaining popularity, novel treatment options have also arisen in orthodontics. By using selective laser melting (SLM), highly customized 3D-printed appliances can be manufactured and combined with preformed components. When combined with temporary anchorage devices (TADs), the advantages of the two approaches can be merged, which might improve treatment efficacy, versatility, and patient comfort. This article summarizes state-of-the-art technologies and digital workflows to design and install 3D-printed skeletally anchored orthodontic appliances. The advantages and disadvantages of digital workflows are critically discussed, and examples for the clinical application of mini-implant and mini-plate borne appliances are demonstrated.

Control of Orthodontic Tooth Movement by Nitric Oxide Releasing Nanoparticles in Sprague-Dawley Rats

Orthodontic treatment commonly requires the need to prevent movement of some teeth while maximizing movement of other teeth. This study aimed to investigate the influence of locally injected nitric oxide (NO) releasing nanoparticles on orthodontic tooth movement in rats.

MATERIALS AND METHODS

Experimental tooth movement was achieved with nickel-titanium alloy springs ligated between the maxillary first molar and ipsilateral incisor. 2.2 mg/kg of silica nanoparticles containing S-nitrosothiol groups were injected into the mucosa just mesial to 1^st molar teeth immediately prior to orthodontic appliance activation. NO release from nanoparticles was measured in vitro by chemiluminescence. Tooth movement was measured using polyvinyl siloxane impressions. Bones were analyzed by microcomputed tomography. Local tissue was assessed by histomorphometry.

RESULTS

Nanoparticles released a burst of NO within the first hours at approximately 10 ppb/mg particles that diminished by 10 × to approximately 1 ppb/mg particles over the next 1-4 days, and then diminished again by tenfold from day 4 to day 7, at which point it was no longer measurable. Molar but not incisor tooth movement was inhibited over 50% by injection of the NO releasing nanoparticles. Inhibition of molar tooth movement occurred only during active NO release from nanoparticles, which lasted for approximately 1 week. Molar tooth movement returned to control levels of tooth movement after end of NO release. Alveolar and long bones were not impacted by injection of the NO releasing nanoparticles, and serum cyclic guanosine monophosphate (cGMP) levels were not increased in animals that received the NO releasing nanoparticles. Root resorption was decreased and periodontal blood vessel numbers were increased in animals with appliances that were injected with the NO releasing nanoparticles as compared to animals with appliances that did not receive injections with the nanoparticles.

CONCLUSION

Nitric oxide (NO) release from S-nitrosothiol containing nanoparticles inhibits movement of teeth adjacent to the site of nanoparticle injection for 1 week. Additional studies are needed to establish biologic mechanisms, optimize efficacy and increase longevity of this orthodontic anchorage effect.

Micro-angiogenic patterns around orthodontic implants migrating in bone: A micro-CT study in the rat tail model

AIM

Recent studies revealed that implants can migrate in bone when subjected to continuous loading. Since this process is suspected to be accompanied by bone remodelling, which requires blood vessel formation, the present work aimed at assessing the micro-angiogenic patterns around migrating implants.

MATERIALS AND METHODS

In 16 rats, two customized implants were placed in a single tail vertebra and connected with contraction springs (forces: 0 N, 0.5 N, 1.0 N, 1.5 N). After 2 or 8 weeks of loading, the animals were scanned by micro-CT before and after vasculature perfusion with a silicone rubber. Vessels were segmented by subtraction of the two micro-CT scans. Vessel thickness (V.Th), vessel volume per total volume (VV/TV), and vascular spacing (V.Sp) were assessed in a peri-implant volume of interest (VOI) around each implant.

RESULTS

At 2 weeks of loading, force magnitude was significantly associated with VV/TV and V.Th values (χ²  = 10.942, p < .001 and χ²  = 6.028, p = .010, respectively). No significant differences were observed after 8 weeks of loading.

CONCLUSIONS

Within the limitations of an animal study, peri-implant vessel thickness and density were associated with force magnitude in the early loading phase, whereas effects diminished after 8 weeks of loading.

Anodized Biomedical Stainless-Steel Mini-Implant for Rapid Recovery in a Rabbit Model

The study aimed to analyze the recovery period of the anodized 316L biomedical stainless steel (BSS) mini-implant through its implantation on femur of rabbit model. The 316L BSS mini-implant was modified by an electrochemical anodization approach with different voltages. The anodized samples were characterized via field-emission scanning electron microscopy, X-ray diffractometry, and X-ray photoelectron spectroscopy. The biocompatibility was assessed by cell culture assay. The anodized mini-implant was implanted on rabbit’s femur then evaluated histologically after 4 and 8 weeks. Analytical results indicated that the topography of the anodized mini-implant at 5 V for 5 min consisted of a dual (micro/nano) porous structure. Oxide film of Cr2O3 was formed on the surface of anodized mini-implant after anodizing with 5 V for 5 min. In vitro cell culture assay revealed that fibroblast cells (NIH-3T3) on the anodized samples were more firmly attached as compared with the control sample. Moreover, histological analysis demonstrated that the anodized mini-implant improved bone recovering at 4 weeks after implantation. Thus, this study suggests that the anodized 316L BSS mini-implant could be a potential choice as anchorage device for effective and efficient orthodontic treatment.

Influence of pre-drilling diameter on the stability of orthodontic anchoring screws in the mid-palatal area

PURPOSE

The aim of this study was to investigate the stability of orthodontic anchor screws (OASs) in the mid-palatal area according to pre-drilling diameter.

METHODS

The success rate of 161 OASs (83 patients, φ2.0 mm, 6.0 mm in length) placed in a corresponding area to the mesial and distal borders of the first molar (mesial zone and distal zone) was assessed according to placement location and pre-drilling diameter (1.2 and 1.5 mm). Placement torque values from 73 OASs with a pre-drilling diameter of 1.2 mm were compared between success and failure groups.

RESULTS

The success rates of OASs pre-drilled with φ1.2 and 1.5 mm were 94.5% and 83.0%, respectively (P < 0.05); corresponding rates in the mesial zone were 100.0% and 77.3% (P < 0.005), and those in the distal zone were 89.2% and 88.6%, respectively. Placement torques of OASs predrilled with φ1.2 mm in the success and failure groups were 25.9 and 19.2 N·cm, respectively (P < 0.05).

CONCLUSION

A smaller pre-drilling diameter was associated with a higher success rate of OASs in the mid-palatal area, especially in the mesial zone. When pre-drilling diameter of 1.2 mm was used for φ2.0 mm OAS, greater placement torque was indicative of greater OAS stability.

A clinical comparative study using anchorage from mini-implants and conventional anchorage methods to retract anterior teeth

Background:

Proclined teeth has been one of the main reasons for compromised esthetics. In a patient with proclined anteriors, retraction is done after 1^st premolar extraction. Absolute/maximum anchorage is required to achieve the best esthetics.

Objective:

We conducted this study with the aim of retracting the proclined maxillary anterior teeth and to check for efficient retraction, type of tooth movement during retraction, and amount of anchorage loss.

Methods:

Patients with proclined anterior teeth where therapeutic extraction of first premolars is required were included in the study, where anchorage was taken with mini-implants in one group, and in the second group, conventional anchorage method of 1^st and 2^nd molar banding with TPA was chosen. Each group consisted of 8 subjects. Lateral cephalogram was taken both preretraction and 4 months after starting retraction to compare anchor loss, rate of retraction, and type of tooth movement of retracted anteriors, in both groups.

Results:

The retraction in the implant group was more than in the conventional group and the difference was statistically significant (P < 0.05). Anchorage loss was seen to be greater in conventional group than in the implant group and was also significant statistically. The type of tooth movement of the anterior teeth on retraction was also compared, with the implant group showing predominantly controlled tipping and the conventional group showing uncontrolled tipping movement.

Comparison of Anchorage Efficiency of Orthodontic Mini-implant and Conventional Anchorage Reinforcement in Patients Requiring Maximum Orthodontic Anchorage: A Systematic Review and Meta-analysis

OBJECTIVE

To compare the clinical effectiveness of mini-implants (MIs) and conventional anchorage appliances used for orthodontic anchorage reinforcement in patients with class I or II malocclusion with bimaxillary protrusion.

MATERIALS AND METHODS

Literature search was conducted through PubMed, Embase, and Cochrane from inception to July 2018. The following Medical Subject Heading terms were used for the search string: "skeletal anchorage", "temporary anchorage devices", "miniscrew implant", "mini-implant", "micro-implant". Standardized mean difference (SMD) and 95% confidence interval (CI) of horizontal and vertical movements of teeth from baseline were used for comparison.

RESULTS

A total of 12 studies were included in the final analysis. MI group significantly lowered mesial movement of molars compared to conventional anchorage group (SMD = -1.48, 95% CI = -2.25 to -0.72; P = .0002). There was significantly higher retraction of incisors in the MI group than in the conventional group (SMD = -0.47 mm, 95% CI = -0.87 to -0.07; P = .02). No significant difference was seen in vertical movement of molars (SMD = -0.21 mm, 95% CI = -0.87 to 0.45; P = .52) and incisors (SMD = -0.30, 95% CI = -1.18 to 0.58; P = .5).

CONCLUSION

MIs seem to be more effective than the conventional anchorage devices in terms of minimizing unintended mesial movement of molars with maximum retraction of anterior teeth.

Immediate orthodontic load on dental implants: an option for adult treatment

The demand for orthodontic treatment in adults has been increasing. However, these patients often require a multidisciplinary approach, due to the lack of posterior teeth, requiring additional anchorage. The skeletal anchorage by endosseous implants is an option, since they may be used later for prosthetic rehabilitation. The application of immediate load on these appliances for orthodontic movement may reduce the costs and total treatment time. This paper discusses the utilization of endosseous dental implants with immediate load for absolute anchorage for orthodontic movement, with later utilization for prosthetic rehabilitation.

An Umbrella Review of the Effectiveness of Temporary Anchorage Devices and the Factors That Contribute to Their Success or Failure

OBJECTIVES

New methodological approaches, such as the umbrella review, constitute an important pathway for synthesizing the scientific evidence provided from studies with a high level of evidence. This study aims to summarize the results on the effectiveness of temporary anchorage devices (TADs) and the factors that contribute to their success or failure during orthodontic treatment in patients of different age groups and to identify the gaps in knowledge based on analysis of the scientific literature.

METHODS

An umbrella review of systematic reviews and meta-analyses was performed. A quality evaluation and a descriptive analysis of the included studies were conducted. The study protocol was registered at the International Prospective Register of Systematic Reviews (PROSPERO: CRD42018094463).

RESULTS

Seventeen systematic reviews and meta-analyses were considered (10 descriptive and 7 with meta-analysis; 12 of high quality and 5 of moderate quality). Variability was observed in the type of intervention and the type of system (TADs). Most of the studies reported high success rates (≥90%), and just one systematic review indicated a low rate of success (≤56%) for the mini-screws. All the studies discussed several factors related to the success of the TADs. These factors were classified as device-related factors, patient-related factors, procedure-related factors, and orthodontic treatment-related factors. Conceptual and methodological gaps were observed when considering the data analysis, the terminology used, and the orthodontic protocols.

CONCLUSIONS

The results should be analysed cautiously because of several research gaps related to the methodological quality and the high heterogeneity of the original studies and because of the necessity to add several clinical and sociodemographic variables to enrich the data analysis.

Comparison of the Anchorage Value of the First Molars Supported with Implant and First Molars Supported with Second Molar during En Masse Retraction

Aims and Objectives:

The aim of this study was to determine the efficacy of mini-implants as adjuncts for intraoral anchorage units for en masse retraction of maxillary anterior teeth in bimaxillary dentoalveolar protrusion cases.

Materials and Methods:

The study sample consisted of 15 patients (10 females and 5 males). The samples were compared for anchorage loss with the implant-supported molar and conventional molar contralaterally in both the maxilla and mandible after six months of retraction period. The mini-implants used were 1.5 mm in diameter and 8 mm in length and were inserted in the first and third quadrant between the roots of second premolar and first molar under local anesthesia at an angle of 45°. For en masse retraction, active tiebacks with ligating (100g) were used bilaterally extending from molar hooks to J-hook on a 0.019” × 0.025” stainless steel arch wire. Lateral cephalograms were taken before and after retraction for assessing the loss of anchorage in maxillary and mandibular first molars.

Results:

Anchorage loss of 1.46 mm in the maxilla and 1.36 mm in mandible was found with conventional molar anchorage, whereas no statistically significant anchorage loss was found in the implant-supported molar side.

Conclusion:

Implant-supported molar side showed better anchorage compared with the conventional molar side. Hence, implant-supported molar can be used as an absolute anchorage unit in the en masse retraction of anterior teeth.

Effectiveness of anchorage with temporary anchorage devices during anterior maxillary tooth retraction: A randomized clinical trial

Objective

This study evaluated the efficiency of anchorage provided by temporary anchorage devices (TADs) in maxillary bicuspid extraction cases during retraction of the anterior teeth using a fixed appliance.

Methods

Patients aged 12 to 50 years with malocclusion for which bilateral first or second maxillary bicuspid extractions were indicated were included in the study and randomly allocated to the TAD or control groups. Retraction of the anterior teeth was achieved using skeletal anchorage in the TAD group and conventional dental anchorage in the control group. A computed tomography (CT) scan was performed after alignment of teeth, and a second CT scan was performed at the end of extraction space closure in both groups. A three-dimensional superimposition was performed to visualize and quantify the maxillary first molar movement during the retraction phase, which was the primary outcome, and the stability of TAD movement, which served as the secondary outcome.

Results

Thirty-four patients (17 in each group) underwent the final analysis. The two groups showed a significant difference in the movement of the first maxillary molars, with less significant anchorage loss in the TAD group than that in the control group. In addition, TAD movement showed only a slight mesial movement on the labial side. On the palatal side, the mesial TAD movement was greater.

Conclusions

In comparison with conventional dental anchorage, TADs can be considered an efficient source of anchorage during retraction of maxillary anterior teeth. TADs remain stable when correctly placed in the bone during the anterior tooth retraction phase.

Can implants move in bone? A longitudinal in vivo micro-CT analysis of implants under constant forces in rat vertebrae

OBJECTIVES

Whereas stationary stability of implants has been postulated for decades, recent studies suggested a phenomenon termed implant migration. This describes a change in position of implants as a reaction to applied forces. The present study aims at employing image registration of in vivo micro-CT scans from different time points and to assess (a) if migration of continuously loaded implants is possible and (b) migration correlates with the force magnitude.

MATERIAL AND METHODS

Two customized machined implants were placed in the dorsal portion of caudal vertebrae in n = 61 rats and exposed to standardized forces (0.5 N, 1.0 N, and 1.5 N) applied through a flat nickel-titanium contraction spring, or no forces (control). Micro-CT scans were performed at 0, 1, 2, 4, 6, and 8 weeks after surgery. The baseline image was registered with the forthcoming scans. Implant migration was measured as the Euclidean distance between implant tips. Bone remodeling was assessed between the baseline and the forthcoming scans.

RESULTS

The findings confirmed a positional change of the implants at 2 and 8 weeks of healing, and a linear association between applied force and velocity of movement (anterior implant: χ²  = 12.12, df = 3, and p = .007 and posterior implant: χ²  = 20.35, df = 3, and p < .001). Bone apposition was observed around the implants and accompanied by formation of load-bearing trabeculae and a general cortical thickening close and also distant to the implants.

CONCLUSION

The present analysis confirmed that implants can migrate in bone. The applied forces seemed to stimulate bone thickening, which could explain why implants migrate without affecting stability.