Although TADs are a relatively recent addition to the orthodontist's arsenal, in reality, they have a long history behind them. There are numerous references in the bibliography to clinicians using some sort of implant to move teeth several years before the introduction of TADs. Roberts was probably one of the first researchers to realize the potential of titanium implants as orthodontic anchorage and to conduct systematic research on the subject. His “first generation” of TADS featured a regular dental implant in the retromolar area that was used to extend second molars and close the space of frequently extracted first molars. Say no to plagiarism. Get a tailor-made essay on “Why Violent Video Games Should Not Be Banned”? Get the original essay However, it was Kanomi who established the term mini-implant and created the TAD as we use it today [4]. Today there are hundreds of different types of this appliance and a new area of ​​orthodontic research. Anchoring Value Newton's third law states that "for every action, there is an equal and opposite reaction." When attempting to move teeth, orthodontists must recognize this law and realize that every time they attempt to move teeth, there is a possibility of simultaneously creating unwanted tooth movement. Orthodontic anchorage has been defined since 1923 as “the base against which an orthodontic force or orthodontic force response is applied” and essentially refers to resistance to unwanted tooth movement. Any structure covered by a periodontal ligament (PDL) will move more or less under the application of force since the PDL is effectively the apparatus that makes orthodontic movement possible. The philosophy behind using TADS as a skeletal anchor is that since they do not have a PDL, reactive forces will be absorbed by the bony structures and only the desired therapeutic movements will be allowed. There are many different ways to get an anchor. A simple classification could be as follows: Anchorage with use of extra-oral support (headgear or face mask, etc.). Anchorage with use of intraoral appliances (Nance, lingual arch, etc.). Intermaxillary anchorage with support of the teeth in the opposing dental arch (class II or III elastics) The fact that absolute anchorage or stabilization of the teeth can only be reliably achieved by using ankylosed teeth or a certain type of implant or plate. Any other type of anchoring creates some sort of reciprocal force that must be manipulated or relies on patient compliance which has a certain. degree of unpredictability [6]. Biology One of the major advantages of TADS is the versatility of placement. The TADS can be placed in close proximity to the anchorage requirement in the alveolar process, usually in an interradicular location. In this way, the need for complex biomechanics is minimized while anchoring remains maximum. There are numerous case reports and articles over the past 20 years emphasizing the clinical application and potential of TADS. [7] However, clinicians and researchers very often assume that TADS works in the same way as endosseous dental implants. It has been shown that after a period of time, regular endosseous dental implants are rigid and able to withstand high orthodontic forces and prolonged loads. On the other hand, TAD research has shown that larger forces (e.g., 10 N) cannot be consistently sustained over an extended period of time (1 to 2 years) and that theMini implants are generally used for the movement of a few teeth over a period of 6 to 8 years. month. Consistently high failure rates appear to be a major problem with TADS. The most significant difference between regular dental implants and many of these TADs is the lack of osseointegration of the mini implants. While it was hoped that the mini-screws would not fully osseointegrate and could be removed after use, the high failure rate (10-30%) and displacement may make this use difficult. For this reason, orthodontists have explored other skeletal anchorage options such as miniplates [12] and other extra-alveolar sites such as the palate for more favorable placement of TADs.OsseointegrationIn general, the definition and The mechanism of successful device implantation has been described by the term osseointegration. Osseointegration is the presence of vital load-bearing bone directly in contact with the implant. Most implant studies examine bone sections and quantify histological parameters at the bone-implant interface. Some of the variables that can be measured are percentage of bone-to-implant contact (%BIC), percentage of bone volume fraction (%BV/TV) in the thread of an implant and bone remodeling (% bone formation rate/year , %BFR/year). However, the definition of a “successful implant” on a histological section is not easy and is not easily measured. Primary and secondary stability cannot be assessed on a histological section and the same goes for almost all mechanical factors. The exact opposite happens with a failing or failing implant. The presence of fibrous tissue and woven bone at the implant interface on histological sections indicates overload and predicts future failure. In general, endosseous implant research presents many challenges. The selection of an appropriate animal model, the interpretation and extrapolation of results to humans, the ability to mimic the clinic by conducting long-term studies (>9 to 12 months) and the analysis of cellular responses and molecular in vitro for the clinical situation are just some of the issues that need to be addressed. Histological variables Numerous studies have been published on different animal models. However, each animal model has limitations and advantages and direct extrapolation of results to humans should be avoided. Some of the most important histomorphometric variables that provide information about mini implants are: Bone implant contact (BIC) is measured in most histological studies. Although bone contact as measured in studies is a static measurement, it actually describes a dynamic process. There is bone remodeling at the implant interface which makes this measurement dynamic. This means that different areas of the implant may come into contact with the bone at different times, as the bone increases or decreases following remodeling. It has been shown that, regardless of species, the rate of remodeling is high near the implant and high at the implant interface, almost certainly ensuring that bone contact changes. The literature indicates that the shape of the implant and the design of the implant threads can impact the degree of contact with the bone. Although measuring bone contact is important, it is not a direct predictor of implant success. A volume (BV) adjacent to the implant and contained in the wires. This specific bone is generated either by contact osteogenesis or by remote osteogenesis [20]. The biological basis here is that bone growth occurs toward an osteogenic surface, in areas where bone did not previously exist. The remodelbony. The manifestation of viable bone at the interface of an implant is the key to success. One method to measure metabolic activity at an implant interface is to estimate bone remodeling in the supporting cortical and trabecular compartments. Measuring bone turnover involves the use of an intravital bone marker. The rate of cortical and trabecular bone turnover in humans is estimated at 2 to 10%/year and 25 to 30%/year, respectively. After implant placement, there is high bone turnover during the initial phases of healing, usually described with the term regional acceleration phenomena (RAP).[22]To assess histomorphometric variables of bone turnover such as rate mineral apposition, mineralized surface/bone surface (MS/BS) or bone formation rates (BFR) are measured in mineralized sections. These variables reveal the dynamic nature of metabolic activity in bone and certainly reveal more information than static variables such as BIC. It's interesting. Analysis of samples taken from various animal species has demonstrated that even after accounting for periods of typical bone healing, a high and persistent rate of remodeling is observed in bone adjacent to the implant over the long term (2 years after implantation). It is unclear, however, whether this is important for the long-term success of the implants. Microcomputed tomography Microcomputed tomography (μCT) is the latest innovation in the study of bone healing and adaptation. μCT images provide 3D reconstructions of the region of interest and help overcome one of the major limitations of standard histology. That is, only a selected number of 2D slices can be examined and the true 3D nature of the implant interface cannot be visualized. It seems that μCT will revolutionize static histological measurements but cannot currently replace dynamic histomorphometry. This new technology also presents new types of problems to overcome, such as scattering and beam hardening. Compared to traditional histology, μCT cannot collect the same information as static measurements. Materials for TADS Titanium is an ideal biocompatible material that allows direct bone contact (osseointegration) between endosseous dental implants and the host bone. Mini screw implants are usually made of titanium alloys. Unlike dental implants, a high degree of osseointegration is not a necessary condition for mini orthodontic implants to function as anchorage devices. Stainless steel bone screws have also been widely used in orthognathic surgery for fracture fixation. Unlike titanium alloy, stainless steel screws tend to develop a fibrous tissue interface between the screw and the bone. This fact allows for easier recovery because it reduces the withdrawal torque. Stainless steel TADs have been used for mass gap closure, showing promising results. There are two major issues regarding the primary stability of steel anchor devices and bone healing responses. Primary stability is defined as mechanical retention upon insertion and is quantified by insertion torque. It has been reported that a wide range of insertion torque values ​​can achieve high TAD success rates. On the other hand, excessive insertion torque can cause negative effects such as bone necrosis and increased microdamage. When microdamage accumulates, it can contribute to MSI failure. The reason is that the mechanical properties of bones are reduced due to,.