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

Cortical bone thickness and bone density effects on miniscrew success rates: A systematic review and meta-analysis

OBJECTIVE

To systematically review the effects of cortical bone thickness (CBT) and bone mass density (BMD) on miniscrew success rates.

METHODS

MEDLINE, the Cochrane Library and Scopus were searched up to June 2020. Of a total of 5734 articles, seven studies were finally selected for the review.

RESULTS

The overall mean success rate weighted by the number of miniscrews was 87.21% (89.87% in the maxilla and 79.24% in the mandible). There was a significantly higher success rate for miniscrews placed in the maxilla compared with those in the mandible (P < .05). CBT showed small positive effect on the success rate of the miniscrews although it failed to reach a statistical significance. The cortical BMD had a minimal effect on the success of the miniscrews. The cancellous BMD demonstrated a very strong effect on the success of the miniscrews in the maxilla, whereas it showed a moderately negative effect in the mandible.

LIMITATIONS

Because of the small number and clinical heterogeneity of the included studies, the results should be interpreted with caution. Further randomized clinical studies with a large sample size are recommended.

Evaluation of success rate and biomechanical stability of ultraviolet-photofunctionalized miniscrews with short lengths

INTRODUCTION

The aim of this research was to verify that ultraviolet light (UV)-photofunctionalization improves the success rate and biomechanical stability of miniscrews regardless of length, and to evaluate the comparability of biomechanical stability between UV-photofunctionalized miniscrews with short lengths and untreated miniscrews with conventional lengths.

METHODS

Eight male beagles (age, 12-15 months; weight, 10-13 kg) received a total of 64 miniscrews, including 7-mm and 4-mm untreated and UV-photofunctionalized, acid-etched miniscrews with the use of a random block design. The cumulative success rates were examined in all studied groups. The insertion and removal torques and screw mobility were measured. Microcomputed tomographic scans and histomorphometric analyses were performed at 8 weeks postoperatively.

RESULTS

The success rates of 7-mm UV-untreated and UV-photofunctionalized miniscrews were 87.5% and 100%, respectively, vs 43.8% for the 4-mm UV-untreated and 4-mm UV-photofunctionalized miniscrews. The rates were significantly different in accordance with the length (P <0.001). There were no differences in the insertion and removal torque and screw mobility between groups according to the length or UV treatment. However, the 4-mm UV-untreated miniscrews yielded a mean bone area ratio of 6.35 ± 7.43%, whereas the 7-mm UV-photofunctionalized miniscrew yielded a mean ratio of 32.17 ± 8.34% (P = 0.037).

CONCLUSIONS

The UV-photofunctionalization significantly increased the biomechanical stability and led to increased bone and miniscrew contact area in dogs with miniscrews of the same length. However, the most important factor that affected the success rate of the miniscrew was the length.

Variability associated with mandibular buccal shelf area width and height in subjects with different growth pattern, sex, and growth status

INTRODUCTION

The primary objective of the study was to quantitatively analyze the width and height of the mandibular buccal shelf area (MBS) at 3 different potential locations for mini-implant placement. In addition, we aimed to compare and contrast the bone parameters of the MBS to study the correlation between different growth status (growing or nongrowing), facial types (hypodivergent, normodivergent, and hyperdivergent), and sex differences (male or female).

METHODS

In this retrospective cone-beam computed tomography study, 678 subjects were included. They were divided into groups according to growth status, facial type, and sex. Scans were imported into the reconstruction program and were aligned in 3 different steps. Measurements were made at 6 different coronal sections: mandibular first molar distal root, second molar mesial root, and second molar distal root (bilaterally). The roots of mandibular molars were used as a reference to measure the width and the roof of the inferior alveolar canal to measure the height of the buccal shelf area. Intraobserver reliability was assessed by measuring the width and height of MBS in 20 randomly selected subjects.

RESULTS

No significant difference (P > 0.05) was found in the width of MBS between males and females. MBS width increased, and height decreased (P < 0.0001) as moved distally from the first molar distal root to the second molar distal root in all 3 facial types irrespective of age or sex. The hypodivergent facial type had significantly greater bone width than the hyperdivergent facial type at all the 3 locations in both males and females. The hypodivergent facial type had significantly less (P < 0.0001) bone height than the hyperdivergent group at all the 3 locations irrespective of age or sex.

CONCLUSIONS

The optimal site for MBS mini-implant is the buccal region of the distal root of mandibular second molars. Hypodivergent patients have more width and less height of MBS compared with hyperdivergent patients. MBS mini-implants are not advised for growing patients because of proximity to developing roots.

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.

Stainless steel or titanium mini-implants?

OBJECTIVES

To investigate whether there was a difference in success rates when stainless steel (SS) was compared to titanium mini-implants (MIs) in orthodontic patients.

MATERIALS AND METHODS

PubMed, Cochrane, Scopus, Web of Science, Lilacs, Google Scholar, Clinical Trials, and OpenGray were searched without restrictions. A manual search was also performed in the references of the included articles. Studies comparing the success rate between SS and titanium MIs were included. Risk of bias (RoB) was assessed using the ROBINS-I (Risk of Bias in Non-randomized Studies-of Interventions) Tool or RoB 2.0 according to the study design. The level of evidence was assessed through GRADE (Grading of Recommendation, Assessment, Development, and Evaluation).

RESULTS

Six studies met the eligibility criteria. One study was a randomized clinical trial that evaluated extraalveolar MIs, and nonrandomized trials examined interradicular MIs. The RCT presented a low RoB, two nonrandomized trials presented a moderate risk, and three presented a high risk. The quality of the evidence was high for the randomized clinical trial and moderate for the nonrandomized trials. Most studies found no difference between materials, with good success rates for both (SS, 74.6%-100%; titanium: 80.9%-100%) and only one study, with a high RoB, showed a higher success rate with titanium MIs (90%) when compared with SS (50%). A quantitative analysis was not because of the great heterogeneity among the studies.

CONCLUSIONS

Although limited, the current evidence seems to show that the material used is not a major factor in the success rate of MIs. Because it has a lower cost than titanium and presents similar clinical efficiency, SS is a great material for orthodontic MIs.

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.

Sex-, growth pattern-, and growth status-related variability in maxillary and mandibular buccal cortical thickness and density

Objective

The primary objective of this study was to quantitatively analyze the bone parameters (thickness and density) at four different interdental areas from the distal region of the canine to the mesial region of the second molar in the maxilla and the mandible. The secondary aim was to compare and contrast the bone parameters at these specific locations in terms of sex, growth status, and facial type.

Methods

This retrospective cone-beam computed tomography (CBCT) study reviewed 290 CBCT images of patients seeking orthodontic treatment. Cortical bone thickness in millimeters (mm) and density in pixel intensity value were measured for the regions (1) between the canine and first premolar, (2) between the first and second premolars, (3) between the second premolar and first molar, and (4) between the first and second molars. At each location, the bone thickness and density were measured at distances of 2, 6, and 10 mm from the alveolar crest.

Results

The sex comparison (male vs. female) in cortical bone thickness showed no significant difference (p > 0.001). The bone density in growing subjects was significantly (p < 0.001) lower than that in non-growing subjects for most locations. There was no significant difference (p > 0.001) in bone parameters in relation to facial pattern in the maxilla and mandible for most sites.

Conclusions

There was no significant sex-related difference in cortical bone thickness. The buccal cortical bone density was higher in females than in males. Bone parameters were similar for subjects with hyperdivergent, hypodivergent, and normodivergent facial patterns.

Miniscrew-anchored maxillary protraction in growing Class III patients

The aim of this article is to report a case series of a miniscrew-anchored maxillary protraction therapy (MAMP). Two male patients presenting with Class III malocclusion were included in this report. The treatment consisted of a hybrid expander and two miniscrews at the anterior region of the mandible anchoring Class III elastics for maxillary protraction. Effective maxillary length, ANB angle and Wits appraisal increased after treatment. Slight dental effects were observed. MAMP therapy produced substantial skeletal effects and might be a good treatment option for Class III growing patients.

The thickness of posterior buccal attached gingiva at common miniscrew insertion sites in subjects with different facial types

INTRODUCTION

The purpose of this study was to assess the thicknesses of maxillary and mandibular posterior buccal approximal attached gingiva at common miniscrew insertion sites, which has critical importance in determining miniscrew length, in subjects with different facial types.

METHODS

One hundred seventy-four subjects with no transversal skeletal discrepancy were included in this study. The facial types of these subjects were evaluated in the sagittal and vertical directions. In the sagittal direction, the subjects were assigned into 3 groups: skeletal Class I, II, and III. Also, each of these groups was divided into subgroups in the vertical direction: low angle, norm, and high angle. Transgingival probing was used to measure the thickness of the buccal attached gingiva.

RESULTS

The thickness of the buccal attached gingiva between the second premolar-first molar ranged from 1.18 ± 0.33 to 1.46 ± 0.28 mm and from 1.28 ± 0.30 to 1.58 ± 0.37 mm in the maxilla and mandible, respectively. The thickness of the buccal attached gingiva between the first-second molars ranged from 1.31 ± 0.41 to 1.60 ± 0.62 mm and from 1.36 ± 0.43 to 1.72 ± 0.52 mm in the maxilla and mandible, respectively. In terms of the thicknesses of the buccal attached gingiva of second premolar-first molar and first-second molars, no statistically significant difference was found between subjects with different facial types.

CONCLUSIONS

It was determined that the thicknesses of maxillary and mandibular posterior buccal approximal attached gingiva varied between 1.18-1.72. At this point, the insertion of miniscrews of 7-8 mm in length was recommended for maxillary and mandibular posterior buccal regions, in order to obtain adequate insertion depth.

Failure rates of miniscrews inserted in the maxillary tuberosity

Introduction:

Anchorage conservation in orthodontics has always been a challenge.

Objective:

The aim of this current study was to find out the failure rate of miniscrews inserted in the maxillary tuberosity (MT) region.

Methods:

This pilot study consisted of 40 patients (23 female, 17 male; mean age = 20.1±8.9 years) that had received 60 MT miniscrews for orthodontic treatment. Clinical notes and pictures were used to find out the primary outcome of miniscrew failure. Independent failure factors were also investigated. Logistic regression analysis was done for predictor’s relation with MT miniscrews failure.

Results:

There was no significant correlation in failure rate according to various predictor variables, except for miniscrews installed by lesser experienced operators, which showed significantly more failure. The odds ratio for miniscrew failure placed by inexperienced operators was 4.16.

Conclusion:

A 26.3% failure rate of mini-implants inserted in the MT region was observed.

Canine substitution of congenitally missing maxillary lateral incisors in Class I and Class III malocclusions by using skeletal anchorage

INTRODUCTION

This prospective cohort study aimed to evaluate canine substitution supported by skeletal anchorage as a viable treatment protocol for patients with maxillary lateral incisor agenesis (MLIA) and skeletal Class I or Class III.

METHODS

Patients (n = 30) who met the following criteria were recruited: (1) bilateral MLIA or unilateral MLIA with a riziform contralateral incisor with a planned extraction; (2) skeletal Class I or Class III; and (3) dentoalveolar discrepancy in the mandible <5 mm. The archwire sequence routine was administered, combined with a rapid palatal expander, temporary intraoral skeletal anchorage device, and intermaxillary traction with Class III elastics. The results of the cephalometric analyses, peer assessment rating indexes, and the patient's smile self-evaluation using the visual analog scale were compared between initial and final treatments.

RESULTS

This study indicated that closing the space in patients with Class I or Class III malocclusion by using temporary intraoral skeletal anchorage devices in the mandible, along with Class III elastics, yielded satisfactory outcomes. Proper occlusion was established by mesialization of the maxillary teeth and correction of the intermaxillary discrepancy, thereby yielding beneficial and significant cephalometric changes after the treatment. The soft tissue profile was maintained when it was harmonious before the treatment and improved posttreatment in patients in whom the profile was initially inharmonious. All occlusions improved, as evidenced by the peer assessment rating index. Smile esthetics were also enhanced after orthodontic treatment for all patients.

CONCLUSIONS

Canine substitution may be safely offered to patients with Class I and Class III skeletal pattern and MLIA.

Safe zones of the maxillary alveolar bone in Down syndrome for orthodontic miniscrew placement assessed with cone-beam computed tomography

The aim of this study was to quantify the available maxillary alveolar bone in a group of individuals with Down syndrome (DS) to determine the best areas for orthodontic miniscrew placement. The study group consisted of 40 patients with DS aged 12-30 years. We also selected an age and sex-matched control group. All measurements were performed on cross-sectional images obtained with cone-beam computed tomography. The selected areas of interest were the 4 interradicular spaces between the distal wall of the canine and the mesial wall of the second molar, in both maxillary quadrants. We measured the vestibular-palatine (VP) and mesiodistal (MD) dimensions to depths of 3, 6 and 9 mm from the alveolar ridge. We also measured the bone density in the same interradicular spaces of interest to 6 mm of depth from the alveolar crest. VP measurements were longer in the more posterior sectors and as the distance from the alveolar ridge increased. MD measurements also increased progressively as the distance from the alveolar ridge increased. In general, both the VP and MD measurements in the DS group were similar among the male and female participants. As age increased, the MD distance increased, while the VP distance decreased. The VP distance was ≥6 mm in at least 75% of the DS group in practically all assessed interdental spaces. The MD distance was ≥2 mm in at least 75% of the DS group only between the first and second molar, to 9 mm of depth from the alveolar ridge. The safe area for inserting orthodontic miniscrews in DS patients is restricted to the most posterior and deepest area of the maxillary alveolar bone.

Three-dimensional quantitative assessment of palatal bone height for insertion of orthodontic implants - a retrospective CBCT study

Background

Orthodontic implants have found widespread use as means of maximum skeletal anchorage in fixed orthodontic treatment, their optimal insertion location in the hard palate, however, is still controversial. The aim of this study was therefore to assess mean bone height across the hard palate and possible age- and sex related differences to identify the most favourable location according to maximum bone height, optimizing primary stability and survival of inserted orthodontic implants.

Methods

In this retrospective cross-sectional study, maxillary pretreatment CBCT scans of 180 healthy orthodontic patients (95♀, 85♂, age 8–40 years) were analysed with regard to vertical palatal bone height in the midpalatal area at 88 validated points distanced 2 mm from each other forming a grid of 0–14 mm posterior to the incisive foramen and 10 mm lateral of the midpalatal suture. Differences in bone height regarding sex and topographical location were assessed by three-way ANOVA.

Results

In general, the midpalatal suture as well as the anterior-lateral palatal region showed distinctly higher mean palatal bone height with its maximum 4 mm posterior of the incisive foramen, whereas bone height was limited at the posterior region of the midpalatal suture. Women generally had significantly decreased palatal bone height compared to men at all measurement points. Higher age was associated with a decrease of bone height in the anterior and posterior lateral palatal region and the median palatal raphe with significant age differences.

Conclusions

The midpalatal suture as well as the anterior lateral palate seem to be most suitable for the insertion of orthodontic implants. Palatal bone height, however, was found to be sex- and age-specific, thus sex- and age-related differences should be taken into account, particularly regarding implant length. The ideal insertion site in the palate with sufficient bone height for orthodontic implants is 0-8 mm (men) or 0-6 mm (women) posterior to the incisive foramen and 10 mm lateral to the midpalatal suture.

Trial registraion

This study has been registered and approved by the Ethics Committee of the University of Witten/Herdecke, Germany (12/2016).

Electronic supplementary material

The online version of this article (10.1186/s13005-019-0193-9) contains supplementary material, which is available to authorized users.

Anchorage effectiveness of orthodontic miniscrews compared to headgear and transpalatal arches: a systematic review and meta-analysis

BACKGROUND

Anchorage in orthodontics can be provided through several extra- and intra-oral sources including headgear, teeth, cortical bone and soft tissue.

OBJECTIVE

The aim of this review was to systematically review the effectiveness of miniscrews in reinforcing anchorage during en-masse retraction of anterior teeth in comparison to conventional anchorage appliances. Search method: Comprehensive searching of the electronic databases was undertaken up to March 2018 in the Cochrane Database of Systematic review, Cochrane Central Register of Controlled Trials, MEDLINE via PubMed and Scopus databases. Additional searching for on-going and unpublished data and hand search of relevant journals were also undertaken, authors were contacted, and reference lists screened. Eligibility criteria: Searches were restricted to randomized clinical trials (RCTs) published in English, which compared anchorage reinforcement using mechanically-retained miniscrews (diameter of 2 mm or less) to conventional anchorage appliances during en-masse retraction of anterior teeth in participants of any age treated with fixed appliances combined with extraction of maxillary premolars.

DATA COLLECTION AND ANALYSIS

Blind and induplicate study selection, data extraction and risk of bias assessment were undertaken. The primary outcome was the amount of mesial movement of the upper first permanent molar (anchorage loss) while secondary outcomes included treatment duration, number of visits, adverse effects and patient-centered outcomes. The risk of bias was assessed using Cochrane risk of bias tool. A random-effects model with its corresponding 95% confidence interval (CI) were generated for comparable outcomes. Statistical heterogeneity across the studies were assessed using the I² and Chi² test. Additional sensitivity tests were implemented.

RESULTS

Seven RCTs met the inclusion criteria, however, data of 241 participants from 6 RCTs (250 miniscrews and 134 conventional anchorage appliances) were meta-analyzed. Qualities of the included RCTs varied from low to high. The standardized mean difference (SMD) of the anchrage loss between the two intervention groups was 2.07 mm ((95% CI (-3.05) to (-1.08), p < .001, I² = 88%, 6 RCTs)) in favour of miniscrews, which was also preserved after excluding the high risk of bias studies (SMD 1.94 mm, 95% CI (-2.46) to (-0.42) p < .001, I² = 93%, 3 RCTs)). Information on overall treatment duration, space closure duration, quality of treatment, patient-reported outcomes, adverse effects and number of visit were limited.

CONCLUSION

The result of the meta-analysis suggested that there is moderate quality of evidence that miniscrews are clinically and statistically more effective in preserving orthodontic anchorage than conventional appliances. However, this conclusion is supported by a small number of studies with variable qualities. High-quality RCTs would give a better understanding of miniscrews effectiveness in providing orthodontic anchorage.

Comparison of BALP, CTX-I, and IL-4 levels around miniscrew implants during orthodontic tooth movement between two different amounts of force

OBJECTIVES

To evaluate the Interleukin-4 (IL-4), bone-specific alkaline phosphatase (BALP), and C-telopeptide of type I collagen (CTX-I) levels in peri-miniscrew crevicular fluid (PMCF) during orthodontic tooth movement between 75 and 150 g of distalization force.

MATERIALS AND METHODS

Thirty miniscrews were placed bilaterally between the maxillary second premolars and first molars. The right and the left maxillary canines were moved distally using either 75 or 150 g of force. PMCF samples were collected before loading (T0); at 2 hours (T1) and 24 hours (T2) later; and on days 7 (T3), 14 (T4), 21 (T5), 30 (T6), and 90 (T7) after force application. Enzyme-linked immunosorbent assay kits were used to determine BALP, CTX-I, and IL-4 levels.

RESULTS

There was no significant difference between the force groups at all time points with respect to BALP, CTX-I, and IL-4 levels (P > .05). There was no significant difference among time points for the two force groups in terms of BALP and IL-4 levels (P > .05). The CTX-I level at T3 was significantly higher than at T0 for both force groups (P < .05).

CONCLUSIONS

Both 75 g and 150 g of orthodontic force are within optimal force limits, and there is no difference in biochemical markers of bone turnover.

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

Background/aim

Retraction of the upper incisors/canines requires maximum anchorage. The aim of the present study was to analyze the efficacy of mini implants in comparison to conventional devices in patients with need for en masse retraction of the front teeth in the upper jaw.

Material and methods

An electronic search of PubMed, Web of Science, and EMBASE and hand searching were performed. Relevant articles were assessed, and data were extracted for statistical analysis. A random effects model, weighted mean differences (WMD), and 95% confidence intervals (CI) were computed for horizontal and vertical anchorage loss at the first molars in the analyzed patient treatments.

Results

A total of seven RCTs employing direct anchorage through implants in the alveolar ridge were finally considered for qualitative and quantitative analysis, and further five publications were considered for the qualitative analysis only (three studies: indirect anchorage through implant in the mid-palate, two studies: direct/indirect anchorage in the alveolar ridge). In the control groups, anchorage was achieved through transpalatal arches, headgear, Nance buttons, intrusion arches, and differential moments.

WMD [95% CI, p] in anchorage loss between test and control groups amounted to − 2.79 mm [− 3.56 to − 2.03 mm, p < 0.001] in the horizontal and − 1.76 mm [− 2.56 to − 0.97, p < 0.001] favoring skeletal anchorage over control measures. The qualitative analysis revealed that minor anchorage loss can be associated with indirect anchorage, whereas anchorage gain was commonly associated with direct anchorage. Implant failures were comparable for both anchorage modalities (direct 9.9%, indirect 8.6%).

Conclusion

Within its limitations, the meta-analysis revealed that maximum anchorage en masse retraction can be achieved by orthodontic mini implants and direct anchorage; however, the ideal implant location (palate versus alveolar ridge) and the beneficial effect of direct over indirect anchorage needs to be further evaluated.

Electronic supplementary material

The online version of this article (10.1186/s40729-018-0144-4) contains supplementary material, which is available to authorized users.

Extra-Alveolar Bone Screws for Conservative Correction of Severe Malocclusion Without Extractions or Orthognathic Surgery

PURPOSE OF REVIEW

Evaluate management of challenging malocclusions conservatively (no extractions or orthognathic surgery).

RECENT FINDINGS

Most malocclusions have a predominately environmental etiology. Optimal esthetics and function are restored by aligning the dentition over the apical base of bone at the appropriate vertical dimension of occlusion (VDO). Extra-alveolar (E-A) anchorage is achieved at three intraoral sites: mandibular buccal shelf (MBS), infrazygomatic crest (IZC), and anterior ramus. MBS and IZC bone screws effectively anchor the conservative correction of severe dental and skeletal malocclusions. All bone screw sites are effective for anchoring lever arms to recover impacted teeth. Rather than extracting teeth, E-A anchorage corrects crowding by retracting the posterior segments to increase arch length. Skeletal malocclusion is corrected by aligning teeth over the apical base of bone and restoring the VDO by retracting and posteriorly rotating the dental arches as segments. Challenging dental and skeletal malocclusions can be treated routinely via determinate mechanics anchored with E-A bone screws.