Success rate of mini- and micro-implants used for orthodontic anchorage: a prospective clinical study

The Orthodontic Mini-Implants Failures Based on Patient Outcomes: Systematic Review

Anchorage is a challenge and essential issue for an orthodontist in determining the success of orthodontic treatment. Orthodontic anchorage is defined as resistance to unwanted tooth movement. Mini-implant is one of the devices that can be used as an anchor in orthodontic treatment. Many cases have reported successful treatment using mini-implant, but there are cases where mini-implants may fail. Failure of mini-implants can affect orthodontic treatment, and it is known that several factors may lead to mini-implant loss in orthodontic treatment. This systematic review aimed to determine the factors influencing mini-implant failure in orthodontic treatment. Articles were selected from electronic databases (PubMed, Google Scholar, The Cochrane Library, ScienceDirect) from January 2015 until 2023 according to the PRISMA method (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) under the PEOS (Population-Exposure-Outcome-StudyType) framework questions for systematic review. The study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) database (CRD42022337684). All data collected were in English, and filtering was done by eliminating duplicate data, meta-analysis, case reports, case series, mini-reviews, and animal studies. The analysis was further divided into three groups, that is, patient-related, implant-related, and operator-related and operator-related (A graphical abstract provided as a Supplementary information [available in the online version]). Twenty-one articles were identified according to the inclusion criteria in the form of retrospective, prospective, in vivo, and randomized controlled trial studies. Mini-implant failures due to patient-related showed six etiological factors, failures due to implant-related had eight etiological factors, and only one factor was operator-related, which may lead to mini-implant failure. The data was extracted without a computerized system and only in English. Mini-implant failure can be caused by many factors; we could not accuse one major factor as a cause. However, the quality or condition of the bones and oral hygiene are factors that play a significant role in obtaining the stability of implants. Mini-implant failure is highly influenced by poor oral hygiene and peri-implant inflammation. Comprehensive diagnostic prior to mini-implant insertion should be appropriately considered. This systematic review describes several factors that can influence mini-implant failure, divided into three groups: patient-related, implant-related, and operator-related (A graphical abstract provided as a Supplementary information [available in the online version]).

Quality of occlusal outcome in adult class II patients after maxillary total arch distalization with interradicular mini-screws

BACKGROUND

The aim of the investigation was to evaluate if a Class II malocclusion in adult patients can be successfully corrected by maxillary total arch distalization with interradicular mini-screws in combination with completely customized lingual appliances (CCLA).

METHODS

Two patient groups were matched for age and gender to determine differences in the quality of final treatment outcome. The treatment results of 40 adult patients with a Class I malocclusion (Group 1) were compared with those of 40 adult patients with a moderate to severe Class II malocclusion (Group 2). All patients had completed treatment with a CCLA (WIN, DW Lingual Systems, Bad Essen, Germany) without overcorrection in the individual treatment plan defined by a target set-up. To compare the treatment results of the two groups, 7 measurements using the American Board of Orthodontics Model Grading System (ABO MGS) and linear measurements for anterior-posterior (AP) and vertical dimensions were assessed at the start of lingual treatment (T1), after debonding (T2B), and compared to the individual target set-up (T2A).

RESULTS

A statistically significant AP correction (mean 4.5 mm, min/max 2.1/8.6, SD 1.09) was achieved in Group 2, representing 99% of the planned amount. The planned overbite correction was fully achieved in both the Class I and Class II groups. There was a statistically significant improvement in the ABO scores in both groups (Group 1: 39.4 to 17.7, Group 2: 55.8 to 17.1), with no significant difference between the two groups at T2B. 95% of the adult patients in Group 1 and 95% in Group 2 would meet the ABO standards after maxillary total arch distalization with a CCLA and interradicular mini-screws.

CONCLUSIONS

CCLAs in combination with interradicular mini-screws for maxillary total arch distalization can successfully correct moderate to severe Class II malocclusions in adult patients. The quality of the final occlusal outcome is high and the amount of the sagittal correction can be predicted by the individual target set-up.

Evidence-based selection of orthodontic miniscrews, increasing their success rate in the mandibular buccal shelf. A randomized, prospective clinical trial

Background

Skeletal anchorage has made it possible to perform complex orthodontic tooth movements that are difficult or even impossible to achieve with conventional orthodontic treatment. Mandibular buccal shelf miniscrews, used for distalization, play a particularly important role in treatment of Class III malocclusion. Unfortunately, stability of the miniscrews placed in the mandible is still considered at higher risk of failure compared to other intraoral locations. The aim of our study was to determine the influence of the miniscrew size on their long-term stability, occurrence of oral mucosa inflammation and pain lasting over 48 h after implantation.

Methods

184 Absoanchor^® miniscrews (Dentos, South Korea) in two sizes: SH2018-10 (length 10 mm, ø 1.8–2.0 mm) and SH1514-08 (length 8 mm, ø 1.4–1.5 mm) were inserted in the mandibular buccal shelf in 92 Caucasians aged 20–50 years, diagnosed with Class III malocclusion that required en-masse distalization of the mandibular dentition. Data was statistically analyzed with the level of significance set at p = .05.

Results

91.3% of the SH2018-10 and 75% of the SH1514-08 miniscrews were stable, and this difference was statistically significant (p < .05). Inflammation of the oral mucosa was noticed around both types of miniscrews and affected 50% of the SH2018-10 and 26.09% of the SH1514-08 group (p < .05). Pain lasting longer than 48 h after implantation was related to 60.87% and 20.65% of the SH2018-10 and the SH1514-08 miniscrews (p < .05), respectively. Inflammation associated with larger SH2018-10 miniscrews did not affect their stability (p > .05), contrary to the SH1514-08 ones (p < .05). When inflammation was present, the overall success rate declined to 64.29%, from 94.74% noted for TADs without inflammation. According to the log-rank test, smaller TADs failed significantly sooner than the larger ones (p = .002).

Conclusion

Larger SH2018-10 miniscrews are the anchorage of choice for the mandibular buccal shelf, despite triggering inflammation and long-lasting pain significantly more often than the smaller ones. Therefore, this issue should be discussed with every patient prior to miniscrew use. Trial registration ID: ClinicalTrials.gov Identifier: NCT05280678 Date of Registration: 15/03/2022. Retrospectively registered.

Buccal bone thickness of posterior mandible for microscrews implantation in molar distalization

BACKGROUND

This study explored the inter-radicular space and buccal bone thickness of the posterior mandibular region to provide an appropriate miniscrew insertion site for lower dentition distalization.

METHODS

The cone-beam computed tomographic (CBCT) records of 63 subjects were collected. Buccal bone thickness (BBT) was measured at four sections: (I) the root of the second premolar(P₁); (II) the mesial root of the first molar(P₂); (III) the distal root of the first molar(P₃); (IV) the mesial root of the second molar(P₄). The narrowest inter-radicular space of the four sections was also detected. Both BBT and inter-radicular space were measured at 4 height levels, 2, 4, 6 and 8mm from the alveolar ridge.

RESULTS

The largest BBT was observed at the mesial root of the second molar at 6 and 8mm, demonstrating a thickness of 6.77±2.50mm and 7.46±1.94mm, respectively. It provided sufficient coverage for mini-implants inserted 10°-30° oblique to the root. Therefore, during distalization of the mandibular dentition, roots have sufficient space to bypass the inclined mini-implants on the lingual side, avoiding miniscrew-root contact. The width between the mesiodistal roots of the first molar was the smallest, showing 1.53±0.69mm and 2.13±0.65mm at 4 and 6mm. Miniscrews implanted in this region had an increased risk of root proximity.

CONCLUSIONS

The most appropriate insertion site at the mandibular buccal shelf was the mesial point of the second molar at 6-8mm from the alveolar ridge, and an insertion angle of 10°-30° was recommended to avoid miniscrew-root contact. CBCT analysis is recommended before implantation due to individual differences.

Success rate of infrazygomatic miniscrews considering their design and insertion techniques. A review

Miniscrews offer the possibility of performing dental movements, minimizing unwanted side effects and enhancing effectiveness. Extra-alveolar miniscrews are ideal as they provide excellent primary stability and avoid anatomical structures. However, in some cases the primary stability is lost before achieving the success of the mechanics used and thus, the most likely causes of failure should be determined. The purpose of this review was to analyze the success rate of infrazygomatic miniscrews, considering their design and the insertion techniques used. Data collection of this literature review was carried out by searching PubMed, Wiley, Google Scholar sites, SCIELO, Elsevier and Dialnet for publication made from 2003 to June 2022. The search was carried out on June 10th, 2022 and the following keywords were used; infrazygomatic crest, miniscrews, anchorage and stability. Different topics were analyzed and discussed highlighting their clinical relevance. After analyzing the 798 articles, 566 were excluded. The remaining articles were re-analyzed and 153 articles were excluded for the title or abstract and 33 articles were excluded for the methodology. Finally, 46 items remained. After thoroughly analyzing all the articles included, this study concluded that the alloy of the miniscrew (stainless steel or titanium), perforation of the maxillary sinus and the placement area (adhered mucosa or mobile mucosa) do not influence the survival of the miniscrew. The evidence also indicates that the percentage of failure is lower in infrazygomatic compared to intraradicular miniscrews. Orthodontists can confidently and safely include infrazygomatic miniscrew in different orthodontic procedures.

The association between thread pitch and cortical bone thickness influences the primary stability of orthodontic miniscrew implants: a study in human cadaver palates

OBJECTIVE

The purpose of this study was to mathematically evaluate the influence of variations in thread pitch and cortical bone thickness on the maximum insertion torque (MIT) and implant stability (IS) of miniscrew implants (MIs).

METHODS

Sixty custom made MIs with a 0.4-, 0.6-, 0.8-, 1.0-, or 1.2-mm thread pitch,12 for each pitch, were randomly placed into the palates of 10 embalmed human maxillae. The MIT was measured with a hand-operated digital torque reader screwdriver with a holding guide, and the IS test was performed using Anycheck. Conebeam computerized tomography was used to measure the cortical bone thickness(CBT) at each MI site. One-way ANOVA, Tukey post hoc test, Pearson's correlation,and multiple linear regression models were performed using the SPSS program.

RESULTS

The MIT and IS tests demonstrated a pitch-dependent decrease. The pitch had a strong negative correlation with MIT and IS, while the CBT had a strong positive correlation with those outcomes. The association between pitch and CBT significantly influenced MI primary stability. Moreover, a strong correlation was found between MIT and IS.

CONCLUSIONS

The MI primary stability, MIT, and IS are strongly influenced by theassociation between MI thread pitch and CBT.

Effect of miniscrew insertion angle in the maxillary buccal plate on its clinical survival: a randomized clinical trial

INTRODUCTION

This study sought to assess the effect of miniscrew insertion angle (vertical and oblique) on its clinical survival under shearing forces in orthodontic patients undergoing canine retraction.

MATERIALS AND METHODS

In this split-mouth randomized controlled clinical trial, 50 miniscrews were placed bilaterally in 25 patients with 45° and 90° insertion angles relative to a line perpendicular to the occlusal plane distal to the maxillary first premolar extraction site. Allocation of insertion angles to the right/left side was random using the Random Allocation Software. The patients, clinician, and statistician were blinded to the allocation of miniscrews to the side of jaw. The patients were followed-up monthly for 6 months. The primary outcome was the clinical survival of miniscrews, which was evaluated at each follow-up session. The secondary outcomes were the miniscrew stability based on the Periotest value (PTV) and the level of pain experienced by patients at 1, 12, and 24 h, and 7 days after miniscrew placement using a visual analog scale (VAS). Data were analyzed using paired t-test, repeated measures ANOVA, and McNemar's test.

RESULTS

The clinical survival rate of miniscrews placed at 90° and 45° angles was 76% and 88%, respectively. This difference was not statistically significant (P = 0.375). No significant difference was noted between the two groups regarding the PTV or the pain score either (P > 0.05).

CONCLUSION

Clinically, the insertion angle of miniscrews (90° versus 45° relative to a line perpendicular to the occlusal plane) has no significant effect on the miniscrew survival rate or stability during orthodontic treatment.

TRIAL REGISTRATION

This trial was registered at www.irct.ir ( IRCT20190901044659N1 ).

PROTOCOL

The protocol was published after trial commencement.

Class II correction by maxillary en masse distalization using a completely customized lingual appliance and a novel mini-screw anchorage concept - preliminary results

Background

The aim of the study was to evaluate the efficacy of a novel en masse distalization method in the maxillary arch in combination with a completely customized lingual appliance (CCLA; WIN, DW Lingual Systems, Germany). Therefore, we tested the null-hypothesis of a significant deviation from an Angle-Class I canine relationship and a normal overjet defined by an individual target set-up after dentoalveolar compensation in Angle Class II subjects.

Methods

This retrospective study included 23 patients, (m/f 3/20, mean age 29.6 years (min/max, 13.6/50.9 years)), with inclusion criteria of an Angle Class II occlusion of more than half a cusp prior to en masse distalization and treatment completed consecutively with a CCLA in combination with a mini-screw (MS) anchorage for uni- or bilateral maxillary distalization (12 bilateral situations, totalling 35). Plaster casts taken prior to (T0) and following CCLA treatment (T3) were compared with the treatment plan / set-up (TxP, with a Class I canine relationship and a normal overjet as the treatment objective). MSs were placed following levelling and aligning (T1) and removed at the end of en masse distalization at T2. Statistical analysis was carried out using Schuirmann’s TOST [two one-sided tests] equivalence test, based on a one-sample t-test with α = 0.025 on each side (total α = 0.05).

Results

Ninety-seven percent of planned correction of the canine relationship was achieved (mean 3.6 of 3.7 mm) and also 97 % of the planned overjet correction (mean 3.1 of 3.2 mm), with a statistically significant equivalence (p < 0.0001) for canine relationship and overjet between the individual treatment plan (set-up) and the final outcome. Adverse effects were limited to the loss of n = 2 of 35 mini-screws. However, in each instance, the treatment was completed, as scheduled, without replacing them. Accordingly, the null-hypothesis was rejected.

Conclusions

The technique presented allows for a predictable correction of an Angle-Class II malocclusion via dentoalveolar compensation with maxillary en masse distalization.

Evaluation of interradicular space, soft tissue, and hard tissue of the posterior palatal alveolar process for orthodontic mini-implant, using cone-beam computed tomography

INTRODUCTION

To investigate the anatomy of the posterior palatal alveolar process, which is often used for placement of the orthodontic mini-implant (OMI), and to suggest simple guidelines for safe placement of OMI.

METHODS

Cone-beam computed tomography (CBCT) scans of 60 patients (30 men, 30 women; age range, 18-39 years; average age, 25.8 years) was used to measure the palatal interradicular distance, the palatal bone thickness, and the palatal soft-tissue thickness. Measurements were performed on the area from the maxillary canine to the maxillary second molar based on the vertical distance apical from the cementoenamel junction. The CBCT data were analyzed by Bonferroni correction for multiple testing and the multivariable mixed linear model.

RESULTS

The palatal interradicular distance was the widest between the second premolar and the first molar and the narrowest between the first and second premolars. The palatal bone thickness at interdental sites was the thickest between the first and second premolars and the thinnest between the first and second molars. The interdental palatal soft-tissue thickness from the canine to the second premolar was thicker than any other area. There were minor measurement differences between genders and positive correlations between vertical distance from the cementoenamel junction plane and all of the parameters.

CONCLUSION

In this study, we evaluated the anatomy of the posterior palatal area using CBCT scans of adult patients. The data will provide guidelines to the clinicians before OMI placement in the posterior palatal alveolar process.

A Custom-Made Orthodontic Mini-Implant-Effect of Insertion Angle and Cortical Bone Thickness on Stress Distribution with a Complex In Vitro and In Vivo Biosafety Profile

BACKGROUND

Orthodontic mini-implant failure is a debatable subject in clinical practice. However, the most important parameter to evaluate the success rate of mini-implant is the primary stability, which is mainly influenced by cortical bone thickness (CBT) and insertion angle.

MATERIALS AND METHODS

Three-dimensional finite element models of the maxilla were created and a custom-made, self-drilling, tapered mini-implant was designed. For the pull-out test, 12 simulations were performed, sequentially increasing the thickness of the cortical bone (1, 1.5 and 2 mm) and the insertion angle (30°, 60°, 90°, 120°). For the force analysis, 24 simulations were performed using an experimental orthodontic traction force of 2 N both in the horizontal and vertical axis.

RESULTS

Insertion angle and CBT have significant impact on force reaction values (p < 0.05). Cortical bone stress had the lowest value when the mini-implant had a 30° insertion angle and the highest value when the implant had a 120° insertion angle, while the CBT was 1 mm. Cortical bone stress had the lowest value with an insertion angle of 90° and the highest value when the implant was inserted at an angle of 30°, while the CBT was 2 mm independent of the force direction. Regarding the biosafety profile of the mini-implant alloy, the present results reveal that the custom-made mini-implant presents good biocompatibility.

CONCLUSIONS

When the CBT is reduced, we recommend inclined insertion while, when the CBT is appropriate, perpendicular insertion is advised.

Evaluation of Stress Pattern Caused by Mini-Implant in Mandibular Alveolar Bone with Different Angulations and Retraction Forces: A Three-Dimensional Finite Element Study

Objective

The objective of the study was to evaluate the stress pattern in cortical and cancellous bones, periodontal ligament, and in the implant itself when a mini-implant (MI) is inserted in the inter-radicular space between mandibular first molar and second premolar at various angulations and different retraction forces.

Methods

Finite element study was conducted with MI insertion at 30°, 45°, 60°, 75°, and 90° angulations in the mandibular posterior region (between second premolar and first molar). At these angulations, horizontal forces of 150, 200, and 250 g were applied to the middle of the MI head. von Mises stress values were then evaluated using the ANSYS software.

Results

Highest von Mises stress values were detected in the MI itself, followed by cortical bone, cancellous bone, and periodontal ligament. The von Mises stress values in cortical bone were highest at 30° angulation and lowest at 90° angulation. In the cancellous bone, the stress value was found to be maximum at 90°. The von Mises stress values in the MI were lowest at 90°. In all four structures, as the load increased from 150 to 250 g, the von Mises stress values increased.

Conclusion

The von Mises stress values in the cortical bone, MI, and periodontal ligament were found to be lowest at 90°. Placement of the MI at 90° appears to be an ideal angulation when applied with a horizontal load. Force range used is within clinically recommended levels; however, the increase in load causes an increase in the stress values.

Risk factors for orthodontic mini-implants in skeletal anchorage biological stability: a systematic literature review and meta-analysis

The reason of the biological stability loss of mini-implants is still a matter of discussion between dentistry professionals. The main objective of this systematic literature review and meta-analysis was to analyze the risk factors that prejudice this loss. A search was made in the electronic databases Pubmed, Scopus, Embase and Cochrane, in addition a manual search was made too in Grey Literature (Opengrey). No limits were set on the year of publication or language. The inclusion criteria were: studies in humans treated with fixed appliances with mini-implants, where the risk factors for secondary stability were evaluated for a minimum of 8 weeks. After eliminating duplicate studies and assessing which ones achieve the inclusion criteria, a total of 26 studies were selected for the qualitative synthesis, 18 of them were included in the quantitative synthesis. Common risk variables were compared in all of them. Analyzing the forest and funnel plots, statistically significant differences were obtained only for location, the upper maxilla having lower risk than the mandible with an odds ratio of 0.56 and confidence interval of 0.39 to 0.80. Prospective studies under controlled conditions should be required in order to obtain a correct assessment of the variables analyzed.

Two distalization methods compared in a novel patient-specific finite element analysis

INTRODUCTION

Orthodontic mini-implants aid in the correction of distocclusions via direct anchorage (pull from mini-implant to teeth) and indirect anchorage (teeth pulled against other teeth anchored by the mini-implant). The aim of this study was to compare stress levels on the periodontal ligament (PDL) of maxillary buccal teeth in direct and indirect distalization against orthodontic mini-implants and accounting for individual variation in maxillary anatomy and biomechanical characteristics of the compact bone.

METHODS

A 3D model of the maxilla containing the different components (teeth, PDL, trabecular and cortical bones) was generated from a computed tomographic scan. Cortical bone was divided into several areas according to previously defined zones. Bone stiffness and thickness data, obtained from 11 and 12 cadavers, respectively, were incorporated into the initial model to simulate the individual cortical bone variation at the different locations. Subsequently, a finite element analysis was used to simulate the distalization modalities.

RESULTS

Stresses at the buccal, palatal, mesial, and distal surfaces were significantly different between adjacent teeth under stiffness but not thickness variation. In both distalization modalities, low or no significant correlations were found between stress values and corresponding cortical bone thicknesses. High significant and inverted correlations were observed at the first molar between stress amounts and cortical bone stiffness (direct modality: -0.68 < r < -0.72; indirect modality: -0.80 < r < -0.82; P <0.05).

CONCLUSIONS

With the use of a novel finite element approach that integrated human data on variations in bone properties, findings suggested that cortical bone stiffness may influence tooth movement more than bone thickness. Significant clinical implications could be related to these findings.

Miniscrews failure rate in orthodontics: systematic review and meta-analysis

Background

Miniscrews in orthodontics have been mainly used for anchorage without patient compliance in orthodontic treatment. The literature has reported changing failure rates.

Objective

The aim of this review was to provide a precise estimation of miniscrew failure rate and the possible risk factors of the mechanically-retained miniscrews.

Search method

Electronic search in database was undertaken up to July 2017 through the Cochrane Database of Systematic Reviews, MEDLINE, Scopus, and Ovid. Additional searching for on-going and unpublished data, hand search of relevant journals and grey lietraure were also undertaken, authors were contacted, and reference lists screened.

Eligibility criteria

Randomised controlled trials (RCTs) and prospective cohort studies (PCSs), published in English were obtained, which reported the failure rate of miniscrews, as orthodontic anchorage, with less than 2 mm diameter.

Data collection and analysis

Blind and induplicate study selection, data extraction, and risk of bias assessment were undertaken in this research. Failure rates and relevant risk factors of miniscrews with the corresponding 95 per cent confidence intervals (CIs) were calculated by using the random-effects model. The heterogeneity across the studies was assessed using the I2 and Chi2 test. The risk of bias was assessed using Cochrane risk of bias and Newcastle-Ottawa Scale. Subgroup and sensitivity analyses were performed in order to test the robustness of the results in meta-analysis.

Results

The 16 RCTs and 30 PCSs were included in this research. Five studies were not included in the meta-analysis due to a lack of the statistical information needed to compute the effect sizes. About 3250 miniscrews from 41 studies were pooled in a random-effect model. The overall failure rate of miniscrews was 13.5 per cent (95% CI 11.5-15.9). Subgroup analysis showed that miniscrews 'diameter, length and design, patient age, and jaw of insertion had minimal effect on rate of miniscrews failure while the type of the gingivae and smoking had statistically significant effect.

Conclusion

Miniscrews have an acceptably low failure rate. The findings should be interpreted with caution due to high-level of heterogeneity and unbalanced groups in the included studies. High quality randomized clinical trial with large sample sizes are required to support the findings of this review.

A prospective, split-mouth, clinical study of orthodontic titanium miniscrews with machined and acid-etched surfaces

OBJECTIVES

To determine whether the success rate and primary stability of surface-treated miniscrews differ from those of nontreated miniscrews.

MATERIALS AND METHODS

Patients who required one or more miniscrews for the same reason in each quadrant were recruited into a single-blinded, split-mouth, randomized, controlled trial with a 1:1 allocation ratio. Self-drilling miniscrews with two surface types were used: those with no surface treatment, and those with an acid-etched surface treatment. The cumulative success rate and primary stability of each type of miniscrew were examined, and factors potentially affecting the success and failure of miniscrews were investigated.

RESULTS

Forty patients were included in the study, with a total of 98 orthodontic miniscrews. The overall success rate was 88.8%, and the respective success rates for acid-etched and machined surface miniscrews were 91.8% and 85.7%. The respective mean insertion torques were 13.62 ± 5.95 N·cm and 13.38 ± 4 N·cm, and periotest values measured immediately after insertion were -0.50 ± 2.77 for acid-etched miniscrews and -0.28 ± 3.36 for machined surface miniscrews. There was no significant difference in the mean insertion torques and periotest values according to surface treatment and jaw.

CONCLUSIONS

Neither the success rate nor the primary stability of acid-etched surface miniscrews and machined surface miniscrews differed significantly. There is a high possibility that miniscrews will fall out in patients who have an open bite or those who require total distalization.

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

INTRODUCTION

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.

METHODS

Orthodontic patients requiring en-masse distalization in the maxilla received antibiotics or a placebo before microimplant placement. Eligibility criteria included 13 years 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 1 hour 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 7 days postoperatively.

RESULTS

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 ± 5.9 years) 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 not increase due to either microimplantation (procalcitonin, P = 0.445; C-reactive protein, P = 0.4) or peri-implantitis. Antibiotic prophylaxis slightly decreased 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.

CONCLUSIONS

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.

REGISTRATION

This trial was not registered.

PROTOCOL

The protocol was not published before trial commencement.

FUNDING

The trial was funded by Wroclaw Medical University; grant number pbmn91 and supported by Diagnostyka.

Prognosis of primary and secondary insertions of orthodontic miniscrews: What we have learned from 500 implants

INTRODUCTION

Although the success of using orthodontic miniscrews for primary insertion has been reported in the literature, few studies have followed up on secondary insertions after failure of the first insertion. In this study, we investigated not only the primary but also secondary success rates of miniscrews and considered the risk factors influencing their stability.

METHODS

Five hundred miniscrews were inserted for orthodontic anchorage in 240 patients. Ninety-eight miniscrews lacked stability; thus, 77 of these were removed and reinserted. We calculated and compared the primary and secondary success rates of insertion. Moreover, we investigated which clinical parameters affected the stability of miniscrews.

RESULTS

The success rate of secondary insertion (44.2%) was significantly lower than that of primary insertion (80.4%). The screw length and jaw receiving the insertion were significantly associated with the stability of miniscrews. The 8.0-mm miniscrews were significantly more stable than the 6.0-mm miniscrews, and the success rate for insertions into the maxilla was significantly higher than that for the mandible.

CONCLUSIONS

Secondary insertions lack stability; therefore, clinicians should be aware of the reduced success rate of reinsertion and know the risk factors to avoid failure of secondary insertions.

Influence of interradicular and palatal placement of orthodontic mini-implants on the success (survival) rate

BACKGROUND

The purpose of this retrospective cohort study was to investigate the success rates of orthodontic mini-implants (OMIs) placed in different insertion sites and to analyse patient and site- related factors that influence mini-implant survival.

METHODS

Three hundred eighty-seven OMIs were inserted in 239 patients for orthodontic anchorage and were loaded with a force greater than 2 N. Two different insertion sites were compared: 1. buccal inter-radicular and 2. palatal, at the level of the third palatal ruga. Survival was analysed for location and select patient parameters (age, gender and oral hygiene). The level of statistical significance was set at p < 0.05.

RESULTS

The overall success rate was 89.1%. There were statistically significant differences between insertion sites; success rate was 98.4% for OMIs placed in the anterior palate and 71% for OMIs inserted buccal between roots (p < 0.001).

CONCLUSIONS

Success rate of OMIs was primarily affected by the insertion site. The anterior palate was a more successful location compared to buccal alveolar bone.

Torque ratio as a predictable factor on primary stability of orthodontic miniscrew implants

OBJECTIVE

To evaluate the torque ratio (TR) as a predictable factor on primary stability of orthodontic miniscrews.

DESIGN

Fifty-eight orthodontic patients (17 men, 41 women; mean age, 21.9 years) with a total of 112 titanium miniscrews of 3 different diameters were subjected. Maximum insertion torque (MIT) and maximum removal torque (MRT) were measured by a digital torque checker at the screw placement. Four weeks after the placement, the stable screw was recorded as a success. Multiple logistic regression analysis was performed to estimate the influence of each clinical variable on success.

RESULTS

Success rates were 82.1% to 89.5%, and there were no significant differences in the 3 types of miniscrews. MIT and MRT showed a positive correlation but did not affect the success rates of miniscrews directly. On the contrary, TR was significantly higher in the success group than in the failure group. In multiple regression analysis, age, TR, and screw proximity had a significant influence on the miniscrew success.

CONCLUSIONS

TR might be related with the miniscrew success rates, and it can be used as a predictable factor on primary stability of orthodontic miniscrew implants. Miniscrew implants should be replaced if MRT is significantly lower than MIT at placement surgery.

Surface analysis of 2 orthodontic mini-implants after clinical use

INTRODUCTION

The purpose of this study was to analyze the design and surface morphology of 2 brands of mini-implants before and after 12 to 18 months of clinical use.

METHODS

We studied 22 mini-implants sold in the Brazilian market by 2 companies (Forestadent, Pforzheim, Germany; and Dental Morelli, Sorocaba, São Paulo, Brazil). The surface morphology of the mini-implants was analyzed by scanning electron microscopy before and after insertion in the oral environment to aid orthodontic movement.

RESULTS

The Forestadent and the Morelli mini-implants showed different shapes (size, screw thread design), and the surface morphology changed after clinical use. The most important surface morphology alterations after clinical use were strain in several parts and fracture of the active thread part of some mini-implants.

CONCLUSIONS

The results of the analyses showed that the screw threads of the mini-implants differ in pitch, angle, and length. The mini-implants also showed differences in body design, active tip, and taper. These differences affect the performance of the mini-implants. After clinical use, all mini-implants showed surface degradation, plastic deformation, and some fractures.

Implants for orthodontic anchorage: success rates and reasons of failures

INTRODUCTION

The aims of this study were to analyze the success rate of mini-implants and miniscrews and to report the reasons behind them.

MATERIALS AND METHODS

An electronic literature search from PubMed databases and a hand search in implant- and orthodontic-related journals were performed until December 31, 2011. Human clinical studies in English that reported temporary anchorage devices used for orthodontic purpose with at least 6 months follow-up were included. In addition, the minimal number of implants had to be at least 10. Implants placed in maxilla, mandible, and hard palate were included.

RESULTS

The initial search resulted in 847 articles, of which 46 were further evaluated. Finally, 29 studies were qualified and classified into 2 groups: implants placed in maxilla and mandible (group 1) and implants placed in hard palate (group 2). A meta-analysis performed for groups 1 and 2 showed 87.8% and 93.8% survival rate, respectively. In addition, the most common cause for implants failure was surgery-related factors.

CONCLUSION

Mini-implant survival rate is location dependent, with those placed in the palate showing higher success rates. In addition, failures most commonly occur because of surgery-related factors.

Prognostic factors associated with the success rates of posterior orthodontic miniscrew implants: A subgroup meta-analysis

OBJECTIVE

To systematically review previous studies and to assess, via a subgroup meta-analysis, the combined odds ratio (OR) of prognostic factors affecting the success of miniscrew implants (MIs) inserted into the buccal posterior region.

METHODS

Three electronic searches that were limited to articles on clinical human studies using MIs that were published in English prior to March 2015 were conducted. The outcome measure was the success of MIs. Patient factors included age, sex, and jaw of insertion (maxilla vs. mandible), while the MI factors included length and diameter. A meta-analysis was performed on 17 individual studies. The quality of each study was assessed for non-randomized studies and quantified using the Newcastle-Ottawa Scale. The meta-analysis outcome was a combined OR. Subgroup and sensitivity analyses based on the study design, study quality, and sample size of miniscrews implanted were performed.

RESULTS

Significantly higher success rates were revealed for MIs inserted in the maxilla, for patients ≥ 20 years of age, and for long MIs (≥ 8 mm) and MIs with a large diameter (> 1.4 mm). All subgroups acquired homogeneity, and the combined OR of the prospective studies (OR, 3.67; 95% confidence interval [CI], 2.10-6.44) was significantly higher in the maxilla than that in the retrospective studies (OR, 2.10; 95% CI, 1.60-2.74).

CONCLUSIONS

When a treatment plan is made, these risk factors, i.e. jaw of insertion, age, MI length, and MI diameter, should be taken into account, while sex is not critical to the success of MIs.

Closure of an open bite using the ‘Mousetrap’ appliance: a 3-year follow-up

Recently, skeletal anchorage devices have been used as anchorage units for upper molar intrusion as a way of correcting an anterior open bite malocclusion. To avoid the surgical procedures associated with the placement of miniplates in the zygomatic area, mini-implants may be inserted palatally or buccally in the alveolar process. However, consideration must be given to the potential risks of root damage and a higher failure rate associated with the placement of temporary anchorage devices (TADs) in the interradicular area. The anterior hard palate provides a safer and more stable alternative for TAD placement. The current paper describes the biomechanical principles and the clinical procedures of ‘Mousetrap’ mechanics using mini-implants in the anterior palate for upper molar intrusion. The stomatognathic response of maxillary molar intrusion is an autorotation of the mandible and so the sagittal implications for each patient must be considered. The presented patient demonstrates successful correction and stability of the treatment result at a three-year review.

Analysis of time to failure of orthodontic mini-implants after insertion or loading

Objectives

This study was performed to evaluate patterns of failure time after insertion, failure rate according to loading time after insertion, and the patterns of failure after loading.

Materials and Methods

A total of 331 mini-implants were classified into the non-failure group (NFG) and failure group (FG), which was divided into failed group before loading (FGB) and failed group after loading (FGA). Orthodontic force was applied to both the NFG and FGA. Failed mini-implants after insertion, ratio of FGA to NFG according to loading time after insertion, and failed mini-implants according to failed time after loading were analyzed.

Results

Percentages of failed mini-implants after insertion were 15.79%, 36.84%, 12.28%, and 10.53% at 4, 8, 12, and 16 weeks, respectively. Mini-implant failure demonstrated a peak from 4 to 5 weeks after insertion. The failure rates according to loading time after insertion were 13.56%, 8.97%, 11.32%, and 5.00% at 4, 8, 12, and 16 weeks, respectively. Percentages of failed mini-implants after loading were 13.79%, 24.14%, 20.69%, and 6.9% at 4, 8, 12, and 16 weeks, respectively.

Conclusion

Mini-implant stability is typically acquired 12 to 16 weeks after insertion, and immediate loading can cause failure of the mini-implant. Failure after loading was observed during the first 12 weeks.

Comparison of short-term effects between face mask and skeletal anchorage therapy with intermaxillary elastics in patients with maxillary retrognathia

INTRODUCTION

The aim of this study was to compare the short-term dental and skeletal effects of a face mask (FM) with those of skeletal anchorage (SA) therapy with intermaxillary elastics in prepubertal patients with skeletal Class III malocclusion.

METHODS

Fifty patients with skeletal Class III malocclusion and maxillary deficiency were divided into two groups. In the FM group, an FM was applied by a bite plate with a force of 400g for each side. In the SA group, mini-plates were placed between mandibular lateral incisors and canines, and mini-implants were inserted between maxillary second premolars and first molars. A bite plate was inserted into the upper arch, and Class III elastics were applied with a force of 200g between each mini-plate and mini-implant.

RESULTS

Mean treatment durations were 0.52±0.09 years for FM and 0.76±0.09 years for SA. After the treatment, statistically significant increases in SNA°, ANB°, A-y, 1-NA, SnGoGn°, Co-A, Co-Gn, and A-Nperp, and reductions in SNB° and FH┴N-Pg were observed in both groups, and these changes were similar in both groups. In the FM group, 1-NB decreased significantly, and in the SA group, it increased significantly (P < 0.05).

CONCLUSIONS

The undesired dentoalveolar effects of the FM treatment were eliminated with SA treatment, except with regard to lower incisor inclination. Favourable skeletal outcomes can be achieved by SA therapies, which could be an alternative to the extraoral appliances frequently applied to treat skeletal Class III patients with maxillary deficiency.

Finite Element Analysis of Bone Stress for Miniscrew Implant Proximal to Root Under Occlusal Force and Implant Loading

Because of the narrow interradicular spaces and varying oral anatomies of individual patients, there is a very high risk of root proximity during the mini implants inserting. The authors hypothesized that normal occlusal loading and implant loading affected the stability of miniscrew implants placed in proximity or contact with the adjacent root. The authors implemented finite element analysis (FEA) to examine the effectiveness of root proximity and root contact. Stress distribution in the bone was assessed at different degrees of root proximity by generating 4 finite element models: the implant touches the root surface, the implant was embedded in the periodontal membrane, the implant touches the periodontal surface, and the implant touches nothing. Finite element analysis was then carried out with simulations of 2 loading conditions for each model: condition A, involving only tooth loading and condition B, involving both tooth and implant loading. Under loading condition A, the maximum stress on the bone for the implant touching the root was the distinctly higher than that for the other models. For loading condition B, peak stress areas for the implant touching the root were the area around the neck of the mini implant and the point of the mini implant touches the root. The results of this study suggest that normal occlusal loading and implant loading contribute to the instability of the mini implant when the mini implant touches the root.

Optimal force magnitude loaded to orthodontic microimplants: A finite element analysis

OBJECTIVE

To find an optimal force that can be loaded onto an orthodontic microimplant to fulfill the biomechanical demands of orthodontic treatment without diminishing the stability of the microimplant.

MATERIALS AND METHODS

Using the finite element analysis method, 3-D computer-aided design models of a microimplant and four cylindrical bone pieces (incorporating cortical bone thicknesses of 0.5, 1.2, 2.0, and 3.0 mm) into which the microimplant was inserted were used. Various force magnitudes of 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0 N were then horizontally and separately applied to the microimplant head as inserted into the different bone assemblies. For each bone/force assembly tested, peak stresses developed at areas of intimate contact with the microimplant along the force direction were then calculated using regression analysis and compared with a threshold value at which pathologic bone resorption might develop.

RESULTS

The resulting peak stresses showed that bone pieces with thicker cortical bone tolerated higher force magnitudes better than did thinner ones. For cortical bone thicknesses of 0.5, 1.2, 2.0, and 3.0 mm, the maximum force magnitudes that could be applied safely were 3.75, 4.1, 4.3, and 4.45 N, respectively.

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 3.75-4.5 N.

Comparison of anchorage reinforcement with temporary anchorage devices or a Herbst appliance during lingual orthodontic protraction of mandibular molars without maxillary counterbalance extraction

Background

Orthodontic protraction of mandibular molars without maxillary counterbalance extraction in cases of aplasia or extraction requires stable anchorage. Reinforcement may be achieved by using either temporary anchorage devices (TAD) or a fixed, functional appliance. The objective was to compare the clinical effectiveness of both methods by testing the null-hypothesis of no significant difference in velocity of space closure (in mm/month) between them. In addition, we set out to describe the quality of posterior space management and treatment-related factors, such as loss of anchorage (assessed in terms of proportions of gap closure by posterior protraction or anterior retraction), frequencies of incomplete space closure, and potential improvement in the sagittal canine relationship.

Methods

Twenty-seven subjects (15 male/12 female) with a total of 36 sites treated with a lingual multi-bracket appliance were available for retrospective evaluation of the effects of anchorage reinforcement achieved with either a Herbst appliance (n_subjects = 15; 7 both-sided/8 single-sided Herbst appliances; n_sites = 22) or TADs (n_subjects = 12; 2 both-sided; 10 single-sided; n_sites = 14). Descriptive analysis was based on measurements using intra-oral photographs which were individually scaled to corresponding plaster casts and taken on insertion of anchorage mechanics (T1), following removal of anchorage mechanics (T2), and at the end of multi-bracket treatment (T3).

Results

The null-hypothesis was rejected: The rate of mean molar protraction was significantly faster in the Herbst-reinforced group (0.51 mm/month) than in the TAD group (0.35). While complete space closure by sheer protraction of posterior teeth was achieved in all Herbst-treated cases, space closure in the TAD group was achieved in 76.9 % of subjects by sheer protraction of molars, and it was incomplete in 50 % of cases (mean gap residues: 1 mm). Whilst there was a deterioration in the canine relationship towards Angle-Class II malocclusion in 57.14 % of space closure sites in TAD-treated subjects (indicating a loss of anchorage), an improvement in canine occlusion was observed in 90.9 % of Herbst-treated cases.

Conclusion

Subjects requiring rapid space closure by molar protraction in combination with a correction of distal occlusion may benefit from using Herbst appliances for anterior segment anchorage reinforcement rather than TAD anchorage.

Reasons for mini-implants failure: choosing installation site should be valued!

Mini-implant loss is often associated with physical and mechanical aspects that result from choosing an inappropriate placement site. It is worth highlighting that:

a) Interdental alveolar bone crests are flexible and deformable. For this reason, they may not offer the ideal absolute anchorage. The more cervical the structures, the more delicate they are, thus offering less physical support for mini-implant placement; b) Alveolar bone crests of triangular shape are more deformable, whereas those of rectangular shape are more flexible; c) The bases of the alveolar processes of the maxilla and the mandible are not flexible, for this reason, they are more likely to receive mini-implants; d) The more cervical a mini-implant is placed, the higher the risk of loss; the more apical a mini-implant is placed, the better its prognosis will be; e) 3D evaluations play a major role in planning the use of mini-implants.

Based on the aforementioned considerations, the hypotheses about mini-implant loss are as follows:

1) Deflection of maxillary and mandibular alveolar processes when mini-implants are more cervically placed; 2) Mini-implants placed too near the periodontal ligament, with normal intra-alveolar tooth movement; 3) Low bone density, low thickness and low alveolar bone volume; 4) Low alveolar cortical bone thickness; 5) Excessive pressure inducing trabecular bone microfracture; 6) Sites of higher anatomical weakness in the mandible and the maxilla; 7) Thicker gingival tissue not considered when choosing the mini-implant.

A study of success rate of miniscrew implants as temporary anchorage devices in singapore

Objective. To find out the success rate of miniscrew implants in the National Dental Centre of Singapore (NDCS) and the impact of patient-related, location-related, and miniscrew implant-related factors. Materials and Methods. Two hundred and eighty-five orthodontic miniscrew implants were examined from NDCS patient records. Eleven variables were analysed to see if there is any association with success. Outcome was measured twice, immediately after surgery prior to orthodontic loading (T1) and 12 months after surgery (T2). The outcome at T2 was assessed 12 months after the miniscrew's insertion date or after its use as a temporary anchorage device has ceased. Results. Overall success rate was 94.7% at T1 and 83.3% at T2. Multivariate analysis revealed only the length of miniscrew implant to be significantly associated with success at both T1 (P = 0.002) and T2 (P = 0.030). Miniscrew implants with lengths of 10–12 mm had the highest success rate (98.0%) compared to other lengths, and this is statistically significant (P = 0.035). At T2, lengths of 10–12 mm had significantly (P = 0.013) higher success rates (93.5%) compared to 6-7 mm (76.7%) and 8 mm (82.1%) miniscrew implants. Conclusion. Multivariate statistical analyses of 11 variables demonstrate that length of miniscrew implant is significant in determining success.

Why are mini-implants lost: the value of the implantation technique!

The use of mini-implants have made a major contribution to orthodontic treatment. Demand has aroused scientific curiosity about implant placement procedures and techniques. However, the reasons for instability have not yet been made totally clear. The aim of this article is to establish a relationship between implant placement technique and mini-implant success rates by means of examining the following hypotheses: 1) Sites of poor alveolar bone and little space between roots lead to inadequate implant placement; 2) Different sites require mini-implants of different sizes! Implant size should respect alveolar bone diameter; 3) Properly determining mini-implant placement site provides ease for implant placement and contributes to stability; 4) The more precise the lancing procedures, the better the implant placement technique; 5) Self-drilling does not mean higher pressures; 6) Knowing where implant placement should end decreases the risk of complications and mini-implant loss.

Histomorphological and torque removal comparison of 6 mm orthodontic miniscrews with and without surface treatment in New Zealand rabbits

AIM

The purpose of this study was to assess the difference of removal torque values (RTV) and the bone-to-implant contact (BIC) between the sand-blasted, large grit, and acid-etched (SLA) surface-treated and the machined surface (MA) miniscrews.

MATERIAL AND METHODS

Miniscrews used in this study were 6mm long with a diameter of 1.5mm. A total of 23 SLA miniscrews and 24 MA miniscrews were placed into the distal femoral condyle of 24 New Zealand rabbits. Removal torque test and the BIC was histologically evaluated at 0 and 8 weeks.

RESULTS

There was no statistical difference between the RTV in the MA group versus the SLA group at both 0 and 8 weeks. Comparing 0-8 weeks, there was no significant difference in RTV of the SLA group (P = 0.48), however the change in the MA group was statistically significant (P = 0.006). Histological observation showed a significant decrease in BIC comparing 0 and 8 weeks for the MA group. The BIC ratio at 8 weeks was statistically significantly higher in the SLA group compared to the MA group.

CONCLUSION

SLA surface preparation does not increase the RTV of miniscrews. Further investigations under loading and a large sample size are required.

Primary failure rate for 1680 extra-alveolar mandibular buccal shelf mini-screws placed in movable mucosa or attached gingiva

OBJECTIVE

To compare the initial failure rate (≤4 months) for extra-alveolar mandibular buccal shelf (MBS) miniscrews placed in movable mucosa (MM) or attached gingiva (AG).

MATERIALS AND METHODS

A total of 1680 consecutive stainless steel (SS) 2 × 12-mm MBS miniscrews were placed in 840 patients (405 males and 435 females; mean age, 16 ± 5 years). All screws were placed lateral to the alveolar process and buccal to the lower first and second molar roots. The screw heads were at least 5 mm superior to the soft tissue. Loads from 8 oz-14 oz (227 g-397 g, 231-405 cN) were used to retract the mandibular buccal segments for at least 4 months.

RESULTS

Overall, 121 miniscrews out of 1680 (7.2%) failed: 7.31% were in MM and 6.85% were in AG (statistically insignificant difference). Failures were unilateral in 89 patients and bilateral in 16. Left side (9.29%) failures was significantly greater (P < .001) compared with those on the right (5.12%). Average age for failure patients was 14 ± 3 years.

CONCLUSION

MBS miniscrews were highly successful (approximately 93%), but there was no significant difference between placement in MM or AG. Failures were more common on the patient's left side and in younger adolescent patients. Having 16 patients with bilateral failures suggests that a small fraction of patients (1.9%) are predisposed to failure with this method.

Effect of the length of orthodontic mini-screw implants on their long-term stability: a prospective study

OBJECTIVE

To analyze the influence of the length of temporary intraoral skeletal anchorage devices (TISAD/TAD) on their long-term stability in the mandible in a homogenous group of patients.

MATERIALS AND METHODS

A group of generally healthy patients of the same gender (female) and with a statistically insignificant age difference (20-29 years) highly homogenous with respect to known factors affecting the success rate of TISAD/TAD was evaluated. One type of TISAD/TAD was applied (6- or 8-mm long). Each patient received both 6- and 8-mm-long TISAD/TAD in randomly selected mandibular quadrants: left or right. The long-term success rate of TISAD/TAD was analyzed.

RESULTS

The 8-mm orthodontic mini-screw implants were significantly more stable than the 6-mm ones in the analyzed group.

CONCLUSION

The length of the TISAD/TAD may be one of the factors that can affect the long-term success rate in the mandibles of 20- to 29-year-old women.

Miniscrews: a simple alternative for complex treatments

The use of mini-implants has already considerably changed the way we plan and perform a large number of orthodontic treatments to the point where, today, we can envisage taking a fresh look at some of our "classical" treatment options. This article will describe a number of clinical cases drawn from several years' experience of working with miniscrews. We present first a brief flashback and an overview of the different indications for micro-implants followed by four case studies presenting treatments which, without miniscrews, would have been treated by much more aggressive approaches.