Skeletal Anchorage In Orthodontics Research Articles

Temporary skeletal anchorage – possibilities and mechanism of application. Literature review

To date, the use of a temporary skeletal anchorage in orthodontic treatment in almost every clinical case. Despite this, there are only two variants of this surgical instrument: mini-screws and mini-plates. Both variants of the skeletal anchorage have their positive and negative qualities, which, to one degree or another, affect the result and timing of treatment. The purpose of this literature review is to describe the main methods of using temporary skeletal anchorage, in which clinical cases their use is possible and contraindicated, as well as what positive and negative aspects can be observed during and after the treatment of orthodontic patients. The search for scientific data was carried out in the PubMed database using such keywords as: orthodontic skeletal anchorage, temporary anchorage, orthodontic mini-screw, orthodontic mini-plate. A literature search revealed that temporary skeletal anchorage allows the surgeon and orthodontist to predictably make changes to the jaw bones that were previously only possible with orthognathic surgery. Before installing a mini-screw or mini-plate, careful planning in the form of an examination and x-ray examination should be carried out. Ultimately, informed consent should be obtained explaining to the patient that orthognathia may still be necessary if the skeletal anchorage method fails. Although this is still a relatively new technique, some issues need to be considered and further clinical research is needed.

Anatomic considerations during placement of mandibular retromolar miniplates for orthodontic anchorage – A study of the characteristics of retromolar fossa

Objectives: The mandibular retromolar area offers a novel site for orthodontic skeletal anchorage. It houses the retromolar foramen (RMF), and surgical interventions in this area can lead to undesirable outcomes. This study aims to assess the characteristics of the RMF and its relation to the occlusal plane (OP) using cone-beam computed tomography (CBCT) data. Material and Methods: This cross-sectional observational in vitro study involved the analysis of CBCT data from 136 samples (68 males and 68 females) within the age range of 18–40 years. The study focused on factors such as the presence or absence of the RMF, whether it was unilateral or bilateral, the number of foramina on each side, and the distance of the RMF from the OP. Data analysis was conducted using the Statistical Package for the Social Sciences software, with P < 0.05 deemed statistically significant at a 95% confidence level. Results: About 39% of the sample showed the presence of RMF. The prevalence of unilateral RMF was higher than that of bilateral RMF. The mean distance of RMF above the OP was 5.99 mm, and that below the OP was 3.82 mm. Conclusion: The high prevalence (39%) of RMF suggests that the retromolar fossa region should be evaluated before the placement of mini-plates. The prevalence of RMF above the OP was significantly higher than that below the OP.

A descriptive review on the use of skeletal anchorage in orthodontics (Part II)

This is the continuation of the first part of our article and includes the design and function of screw-type orthodontic mini-implants, placement sites, surgical procedures, loading approaches and a little about biocortical and resorbable implants.

A descriptive review on the use of skeletal anchorage in orthodontics (Part I)

Anchorage has been defined as a resistance to unwanted tooth movement. It is imperative for the treatment of both dental and skeletal malocclusions. Skeletal anchorage provides better chances to obtain absolute anchorage in orthodontic tooth movement. The topic of skeletal anchorage is vast and compiling it in one single article will be an injustice to the readers. So, we have divided this into two review articles under the headings of introduction, evolution and historical background, the means of skeletal anchorage which will be discussed in this first part followed by the design and function of screw-type orthodontic mini-implants, placement sites, surgical procedures, loading approaches, biocortical and resorbable implants and conclusion in the second part.

Redefining our protocol of the orthognathic surgery-first approach after 10 years of experience

The objective of this study was to update and redefine some concepts of the surgery-first (SF) approach, regarding its indications and contraindications, virtual planning work-up, surgical tips, and postoperative orthodontic benefits, after 10 years of experience. A retrospective analysis was made of orthognathic surgical procedures following the SF protocol between January 2010 and December 2019 to review inclusion and exclusion criteria, diagnostic workflow, surgical tips, and postoperative outcomes. A total of 148 SF procedures were performed during this period, which corresponded to only 9.2% of the total orthognathic surgeries performed, which means that we have broadened the exclusion criteria instead of reducing them. Surgical tips include interdental corticotomies solely in cases of anterior crowding and leaving the intermaxillary fixation miniscrews in place postoperatively for orthodontic skeletal anchorage. The mean duration of postoperative orthodontic treatment was reduced in comparison to conventional surgery (36.8 vs 87.5 weeks). The overall degree of satisfaction was high not only for the patients, but also for the orthodontists and surgeon. SF is especially indicated for patients who desire an immediate aesthetic result, with short-term orthodontics, or for treatment of sleep-related breathing disorders, if they meet the established criteria.

Surgery-First Approach in the Orthognathic Patient.

The surgery-first approach (SFA) has become a recent alternative to the conventional 3-stage approach to orthognathic surgery. Skeletal anchorage in orthodontics has facilitated the resurgence of this treatment sequence. By eliminating the presurgical phase of orthodontic treatment, patients have immediate resolution to their facial deformity. Treatment duration has been shown to be reduced; the difference with the conventional approach being approximately 5months. Patient satisfaction with this approach is very high as measured by quality-of-life surveys. This article describes the indications and step-by-step approach of this technique in conjunction with virtual surgical planning.

Factors Associated with the Success of Orthodontic Miniscrews

Background and aims. Nowadays miniscrews are widely used as skeletal anchorage in orthodontics. However, the success rate of miniscrews is less than that of osseointegrated implants. The aim of this retrospective study was to evaluate factors influencing the success rate of orthodontic miniscrews. Materials and methods. Data of 244 miniscrews in 122 patients (99 females and 23 males, with a mean age of 19 years and 6 months) were collected. Logistic regression analysis was used to evaluate the effect of age, gender, placement side and insertion torque on the success rates of miniscrews. Results. The overall success rate of miniscrews was 90.6% in the present study (221/244). Logistic regression analysis showed that the success rate of miniscrews was not under the influence of variables such as gender, placement side and miniscrew brand. However, age groups and insertion torques over 10 Ncm decreased miniscrew success rates. In this context, the success rates of miniscrews in patients under 16 years of age was less than those in patients over 16 years of age (P<0.001) and the success rates of miniscrews with insertion torques ≤10 Ncm were higher than those with insertion torques over 10 Ncm (P=0.019). Conclusion. We concluded that patients under 16 years of age and insertion torques over 10 were increased the failure of orthodontic miniscrews.

Skeletal anchorage in orthodontics: possibilities and limits

This presentation highlights the new treatment options by the introduction of Temporary Anchorage Devices (TADs) in orthodontics with special respect to the palatal implants and miniscrews. The indications and limitations of such TADs are presented on the basis of clinical cases and the scientific literature. TADs are mainly indicated for space closure of tooth agenesis, treatment of asymmetries and the extension of orthodontic treatment options in orthognathic borderline cases. The knowledge of the limits of such systems and their special biomechanics are fundamental. In growing children though, conventional anchorage systems may often be preferable.

Skeletal anchorage in orthodontic treatment of Class II malocclusion: Contemporary applications of orthodontic implants, miniscrew implants and miniplates

Over the past decade, orthodontic skeletal anchorage devices have gained significant traction in the orthodontic community. These devices have become instrumental in vertical control of the dentition, anteroposterior movement of the dentition, and in particular, molar distalization for the treatment of Class II malocclusion. The collaborative efforts of numerous clinicians are pooled in this new textbook on the treatment of Class II malocclusions with skeletal anchorage, especially with miniscrew implants and miniplates. This well-organized book begins with a brief review of Class II malocclusions and their treatments using conventional noncompliance appliances and quickly transitions to an extensive review of temporary anchorage devices, covering the range of traditional implants, onplants, miniplates, and miniscrew implants. Because of the abundance of brands in the marketplace, particular attention is given to miniscrew implants, with a detailed analysis of their composition and mechanical structure. This left this reviewer amazed at the progress with miniscrew implants since our first publication on the topic.1Baumgaertel S. Razavi M.R. Hans M.G. Mini-implant anchorage for the orthodontic practitioner.Am J Orthod Dentofacial Orthop. 2008; 133: 621-627Abstract Full Text Full Text PDF PubMed Scopus (65) Google Scholar The detailed and particular attention given to the insertion site and the insertion technique makes this a must-read book for every orthodontic resident and novice user of temporary anchorage devices because various fabrication techniques for surgical guides are discussed to assist clinicians in avoiding common placement complications. The text is peppered with abundant, high-quality photographs that aid the reader in developing a thorough understanding of the treatment mechanics used in the presented cases. An extensive review of molar distalization is presented, using both direct and indirect anchorage techniques with onplants, zygomatic anchorage, and palatal and interdental miniscrew implant anchorage. Although high-quality treatment results are presented with many unique treatment techniques and treatment mechanics, some presented cases had complicated and at times inefficient treatment techniques that may be best suited for educational institutions, rather than the moderate to large private practices that are often found in North America. The book concludes with a review of risk factors, complications including root and bone responses, inadvertent root contact during placement, maxillary sinus perforation, and risk-management must-knows for practitioners placing miniscrew implants. Overall, the book is a valuable resource and reference for any orthodontist, periodontist, and maxillofacial surgeon who places miniscrew implants and miniplates as anchorage aids during orthodontic treatment.

Risk factors associated with the failure of miniscrews - A ten-year cross sectional study

The aims of this study were to identify (1) patient-related factors (sex, age, craniofacial pattern and smoking habit), (2) miniscrews implants (MSI)-related factors (length and diameter) and (3) location-related factors [bone (maxilla or mandible) and area (buccal, lingual and alveolar ridge)] that may be associated with MSI loss of stability. A total of 1356 MSI were installed in 570 patients (423 females and 147 males) with mean age of 42.7 during a 10-year period and were clinically evaluated once a month until the end of the proposed movement. Length (5, 7, 9 and 11 mm) and diameter (1.3, 1.4 and 1.6 mm) of the MSI were selected according to insertion site. The evidence of clinical mobility during treatment or fracture during insertion was considered as failure. A total success rate of 89.1% was observed. There was no statistically significant difference in loss of stability when considering age, sex, craniofacial pattern or smoking habit. Considering diameter, there was no statistically significant difference (p = 0.645), but the shorter miniscrews (5 mm) showed higher failure rates (p < 0.001) than the longer ones. There were more loses (p < 0.001) in the mandible than in the maxilla, but the area (buccal, lingual or alveolar ridge) did not interfere in the results (p = 0,421). It can be concluded that MSIs are effective for skeletal anchorage in orthodontics. Patient-related factors, such as sex, age, smoking habit and craniofacial pattern, did not affect MSI success. However, the use of shorter MSIs (5 mm) was inversely proportional to failure probability, and loss of stability was greater in the mandible.

Studii şi observaţii clinice asupra ancorajului ortodontic cu miniimplanturi

Miniimplant recently became a way of orthodontic treatment. Compared to the other implants, miniimplants are relatively small, allowing them to be placed between the dental roots in various areas of the jaws and serve as skeletal anchorage for orthodontic tooth movements. The use of miniimplants for orthodontic skeletal anchorage may be an predictable and accurate alternative without requiring patient compliance, compared with conventional versions of anchorage. The paper presents a series of clinical cases seen and treated within the dental office of S.C. RANDI SRL and in the Department of Orthodontics at New York University College of Dentistry.

Impact of radiation history, gender and age on bone quality in sites for orthodontic skeletal anchorage device placement

Stability of orthodontic miniscrew implants is prerequisite to their success and durability in orthodontic treatment. As investigations revealed a positive correlation of miniscrew stability to periimplant bone quality, it has been the aim of this study to analyze the bone structure of resection preparations of human mandibles histologically by investigating the samples according to age, gender and exposure to radiotherapy. Inflammation- and tumor-free alveolar bone sections from human mandibles (n = 31) with previously diagnosed carcinoma, chronic osteomyelitis or cysts were analyzed histomorphologically and histomorphometrically as to the dimension of trabeculae in cancellous areas. Group A investigated the impact of a history of radiation therapy, group B of gender and group C contrasted biopsies from individuals aging under 60 or over 60 years. Statistics were performed using the Kruskal-Wallis-test. Radiation, gender and age did not significantly influence bone density. The mean bone density averaged 40.7 ± 15.0% of spongiosa for the total collective with a median age of 58.4 years ± 14.7 years. Our findings provide new information on bone quality, thus contributing to a more precise evaluation of the parameters affecting and those not affecting miniscrew implant stability. On the basis of these results, the formulation of clinical guidelines for risk assessment of therapeutic approaches in patients prior to insertion of orthodontic skeletal anchorage devices seems to be conceivable.

Orthodontic skeletal anchorage using a palatal external plate

We have developed the Anchor-Lock external plate system, which is fitted on the palate for the purpose of orthodontic skeletal anchorage. The aim of this study was to introduce the Anchor-Lock and assess its success rate. The Anchor-Lock is composed of titanium screws of 2·0-mm diameter and a titanium plate of 1·0-mm thickness. The external plate is rigidly interlocked with the heads of the screws, which are implanted trans-mucosally into palatal bone. Three types of Anchor-Lock are available. These were applied to 137 orthodontic patients (104 females and 33 males) aged 10-54 years. Two types of plate were used, a straight-shaped plate applied to the hard palate and to the anterior palate and a double-Y-shaped plate applied after tooth-borne rapid maxillary expansion. Success rate of the Anchor-Lock was 92·0% overall. No significant difference in success rate was found by age or sex of patients. Type or screw length of the Anchor-Lock did not affect success rate significantly. Success rate was significantly increased by the use of the surgical stent. The Anchor-Lock was effectively applied to distalize and/or intrude the upper molars. The Anchor-Lock system appears suitable for clinical use as an alternative to conventional screw- and plate-type orthodontic implants.

Effects of a newly designed apparatus on orthodontic skeletal anchorage.

Objective:An appliance was designed to increase the cortical bone surface contact area of miniscrew implants (MSIs). The purpose of this in vitro study was to evaluate the effects of this appliance on the anchorage force resistance and the stability of orthodontic MSIs.Materials and Methods:A total of 48 MSIs were placed into bone specimens prepared from the ilium of bovines. Half were placed with the newly designed apparatus and half were placed conventionally. All the specimens were subjected to tangential force loading perpendicular to the MSI with lateral displacement of 0.6 mm, using an Instron Universal Testing machine. The maximum removal torque of each tested specimen was also recorded. Both study and control groups were divided into two subgroups based on whether they had thin and thick cortical bone.Results:The test group had statistically higher force anchorage resistance and maximum insertion torque values than the control group (P < 0.001). The results were found to be more significant in cases in which the cortical bone was thin (P < 0.001).Conclusions:Within the limits of this in vitro study, the present findings suggest that the newly designed apparatus might have a favorable effect on MSI stability in patients presenting with thin cortical bone. Clinical studies are necessary to confirm the results that were observed in vitro.

Finite element analysis of the stress state produced by an orthodontic skeletal anchorage system based on miniscrews

Aims: The aim of this work is to produce detailed analysis and quantitative results of the stress state induced in an inferior first molar tooth by an orthodontic mesialization system based on a mini-screw, a bracket, and a rubber elastic string. Materials and Methods: The implant was modeled as a non-osteointegrated Ti-6Al-4V standard mini-screw, implanted in the anterior-buccal region of human jaw. 3D realistic models were constructed using data based on micro-computed tomography scans of human teeth as found in the literature. A couple of self-balanced forces of 4 N was applied and finite element method analysis was run and produced an approximate solution, which allowed to display stress distribution over the whole model. Materials' behavior was assumed elastic and linear. This approximation applies to the 1 st stage of the orthodontic treatments. Results: A detailed qualitative and quantitative analysis of the stress state is presented through images. Results in terms of stresses and displacements were studied to exclude any possibility of bracket debonding, bone failure, and loss of stability of the screw. Results were compared to the ultimate strengths of the bio-materials involved using engineering failure criteria. The actual stress state was found to be lower than the critical values. Conclusion: Results allows to qualitatively see the amount of bone, surronding the mini-screw, and the tooth, that undergoes stress. Furthermore, quantitative analysis of stress could exclude failure in alveolar bone and detachment at the enamel-bracket interface. The applied force and devices were proved to be safe to use for this kind of orthodontic facilities.

Implantable Devices: A Review of Current Treatment Modalities

The use of implantable devices as direct adjuncts to orthodontic treatment as compared to the use of conventional dental implants is relatively less in number. Currently, a limited number of such devices are used to aid in orthodontic treatment. The options include conventional titanium endosseous dental implants, palatal implants, titanium miniscrews (also known as micro- or mini-implants), and mini-bone plates. Integration of dental implants or implantable devices into contemporary orthodontic practice has the following possible advantages: Serving as a means of increasing orthodontic anchorage, virtually eliminating patient compliance issues with regard to wearing of appliances, decreasing overall treatment time, and occasionally permitting orthodontic treatments previously thought to be impossible without surgery. This article is a review of the currently available options for use of implantable devices as sources of temporary skeletal anchorage in orthodontics.

FEM analysis of a new miniplate: stress distribution on the plate, screws and the bone

Non-homogeneous force distribution along the miniplates and the screws is an unsolved question for skeletal anchorage in orthodontics. To overcome this issue, a miniplate structure was designed featuring spikes placed on the surface facing the cortical bone. The aim of this study was to examine and compare the force distribution of the newly designed plate-screw systems with the conventional one. A model of bone surface with 1.5 mm cortical thickness, along with the two newly designed miniplates and a standard miniplate-screw were simulated on the three-dimensional model. 200 g experimental force was applied to the tip of the miniplates and the consequential effects on the screws and cortical bone was evaluated using three-dimensional finite element method. As a result of this finite element study, remarkably lower stresses were observed on the screws and the cortical bone around the screws with the newly designed miniplate when compared with the conventional one. The newly designed miniplate that has spikes was found effective in reducing the stress on and around the screws and the force was distributed more equivalently.

Mini-implants in the anchorage armamentarium: new paradigms in the orthodontics.

Paradigms have started to shift in the orthodontic world since the introduction of mini-implants in the anchorage armamentarium. Various forms of skeletal anchorage, including miniscrews and miniplates, have been reported in the literature. Recently, great emphasis has been placed on the miniscrew type of temporary anchorage device (TAD). These devices are small, are implanted with a relatively simple surgical procedure, and increase the potential for better orthodontic results. Therefore, miniscrews not only free orthodontists from anchorage-demanding cases, but they also enable clinicians to have good control over tooth movement in 3 dimensions. The miniplate type also produces significant improvements in treatment outcomes and has widened the spectrum of orthodontics. The purpose of this paper is to update clinicians on the current concepts and versatile uses and clinical applications of skeletal anchorage in orthodontics.

Impact of bone quality, implant type, and implantation site preparation on insertion torques of mini-implants used for orthodontic anchorage

Mini-implants are widely used as skeletal anchorage in orthodontics. To reduce implant loss rate, sufficient primary stability is required. This study quantitatively analysed the impact of bone quality and pre-drilling diameter on the insertion torque of five different mini-implants. Twenty pig bone segments were dissected and embedded in resin. The insertion torques of two different mini-implant types (Tomas Pin, Dentaurum, Germany, 8 and 10 mm; and Dual Top, Jeil, Korea, 1.6 mm × 8 and 10 mm plus 2 mm×10 mm) were measured. After preparation of the implant sites using pilot drill diameters 1.0, 1.1, 1.2 and 1.3mm, 30 implants were inserted into each bone segment. Five reference implants were inserted into each segment for comparison. Micro CT evaluated bone compacta thickness. Insertion moments of orthodontic mini-implants, and hence primary stability, varied strongly depending on compacta thickness, implant design, and pre-drilling at the implant site. The Dual Top consistently showed higher primary stability than the Tomas Pin. Insertion moments higher than 230 Nmm resulted in fractures in some cases. Compacta thickness, implant design and preparation of implant site affect the insertion torque of mini-implants for orthodontic anchorage. To avoid fractures and high bone stresses, optimum pre-drilling diameters should be chosen.

Stability of a Locking Plate and Self-Drilling Screws as Orthodontic Skeletal Anchorage in the Maxilla: A Retrospective Study

The aim of this retrospective study was to determine the success rate of an orthodontic skeletal anchorage system consisting of a locking plate and 2 self-drilling screws to intrude the upper molars and detect factors that contribute to its stability. The subjects were 32 orthodontic and generally healthy patients who had skeletal anchorage plates placed supraperiosteally and unilaterally or bilaterally. The anchorage plate was considered successful if the plate remained stable throughout the period of intrusion of the upper molar without any movement, persistent pain, or infection and was then retrieved without difficulty. The success rates of the anchorage plate were statistically analyzed on the basis of clinically categorized variables. The 32 patients comprised 6 male and 26 female individuals with ages ranging from 11.4 to 35.1 years. The overall success rate of the total 61 plates was 93.4%. No significant differences were observed among the respective success rates analyzed in accordance with gender, age, side of placement, and length of the screws. The thickness of the bony walls that supported the screws was significantly greater in the success group (mean 1.6 +/- SD, 0.2 vs 1.0 +/- 0.1 mm, P < .001). Bone thickness is a critical factor in supporting the self-drilling screws and locking plate. Skeletal anchorage combining the plate and 2 screws promises a higher success rate with a thicker bone than with the threshold value of thickness that exists within the 1.1 to 1.4 mm range in the maxillary walls.