# Influencing Factors in Autotransplantation of Teeth with Open Apex: A Review of the Literature
## 1 Introduction  
When a tooth loss occurs, it is essential to replace it to prevent functional, aesthetic and/or psychological problems. Currently, the most common treatments when a dental absence is faced are removable prostheses, implants or orthodontics. However, there is another less known option called dental autotransplantation, a promising alternative, especially in young patients, where the treatments mentioned above may not be suitable or cannot be performed [1, 2, 3, 4, 5, 6, 7]. This technique has various advantages compared with conventional methods, such as the use of autologous tissue to preserve the periodontal ligament, the preservation of the masticatory function and the favorable aesthetic results [1, 2, 3, 4].  
Dental autotransplantation is defined as the transplantation of an impacted or erupted tooth to another site, extraction socket or surgically prepared socket in the same individual [1, 2, 8]. This technique is used to replace a tooth that has to be extracted either because it has been lost due to trauma, its restoration is impossible, endodontic treatment has failed or it has been fractured [1, 2, 9]. A success rate of 89.68% (any signs of pathology or need for additional procedures) and a survival rate of 98% (persistence of the transplanted tooth, with the need for additional procedures) have been calculated in open apex autotransplantation [10] and 80% success and 95% survival in the mature apex [11].  
The extracted tooth's socket is used to hold the transplanted tooth, making the necessary modifications to make it fit perfectly. If the tooth's absence is maintained over anextended period of time, a new socket may need to be made using drilling techniques similar to those used in implantology [1; 2; 9; 12; 13].  
Dental autotransplantation presents a series of advantages. One of the most important is that it can be performed in growing patients, unlike current implantology techniques [4; 5; 14; 15]. In addition, it also allows one to maintain a vital periodontitis, allowing continuous growth, the preservation of the volume of the alveolar bone, better conservation of the interdental papillla [5] and the possibility of dental movement through orthodontic forces [2; 5; 16; 17; 18]. Likewise, it has been proven that the longevity and prognosis of autotransplanted teeth are comparable with those of dental implants [9].  
On the other hand, a series of complications can occur during or after performing this technique, such as iatrogenesis or errors regarding case selection, which can cause the patient to present ankylosis, root resorption, pulp necrosis or loss of the periodontal ligament. These complications can eventually lead to tooth loss [1; 19; 20; 21]. When root formation is incomplete, it is more difficult for these complications to occur, since the pulp tissue has greater regeneration potential. However, in teeth in which root formation is complete, complications may be more likely to occur. For this reason, it has been suggested that root canal treatment should be performed 2 weeks after the autotransplant has been performed [1; 19; 20; 21].  
Considering the novelty of this technique in daily dental practice, its promising success rates and its potential complications, it seemed convenient to carry out an updated review on the factors influencing the results of open apex dental autotransplantation in humans.