Dental autotransplants: evidence in the literature
Tooth loss, whether due to trauma, developmental abnormalities or pathological conditions, is an extremely common problem that affects individuals of all ages. Traditional methods of tooth replacement such as prosthetics on natural teeth or implant prosthetics offer functional solutions, but each has inherent limitations. In this context, the autotransplantation of teeth has evolved as a promising alternative, with the potential to preserve both architecture and functionality. The technique involves the transfer of a donor tooth, often a third molar or premolar, to replace a missing or damaged tooth. Dental autotransplantation technique The dental autotransplantation process typically involves several stages, including: The donor tooth, often a third molar or premolar, is extracted while attempting to preserve the periodontal ligament, which plays a crucial role in revascularisation and integration into the recipient site (2). Once extracted, the tooth is carefully inserted into the prepared recipient site, which is usually the post-extraction socket of a lost tooth. The next step involves splinting the tooth to neighbouring teeth to stabilise it during the healing process. Two key aspects: timing and preparation One essential aspect of the procedure is the timing of the transplant. Successful outcomes are more likely when the donor tooth is transplanted immediately after extraction, as prolonged extraoral time may lead to complications such as root resorption (3). Some studies suggest that transplantation should occur within 15-20 minutes of extraction to minimise damage to the periodontal ligament (4). In addition to the timing of the procedure, site preparation is critical to success. The recipient site must be carefully prepared to ensure that the donor tooth fits properly and that the root surfaces are free of contamination (5). Several techniques, including the use of saline or specialised growth factors, may be used to promote healing and reduce the risk of complications. Tooth autotransplantation: factors that influence success The success of tooth autotransplantation is influenced by a number of factors, ranging from specific patient characteristics to surgical variables. A review of the literature has highlighted several success factors, including the age of the patient, the type of tooth transplanted, the quality of the periodontal ligament and the surgical technique used. 1) Patient’s age Age is one of the most significant factors influencing the success of tooth autotransplantation. Younger patients, particularly those between the ages of 10 and 25, tend to have higher success rates due to the greater root development capacity and robust healing capacity of their periodontal tissues (6). Conversely, older patients may have lower success rates due to reduced periodontal ligament vitality and slower healing processes (7). 2) Type of tooth The type of tooth transplanted also plays a role in the procedure’s success. Third molars (wisdom teeth) are the most commonly used donor teeth, as they are often extracted for orthodontic reasons and are suitable for transplantation. However, some studies indicate that the success rate may vary depending on the type of tooth. For example, premolars have a higher success rate than molars due to their smaller root surface and better adaptability to the recipient site (3). 3) Condition of the periodontal ligament (PDL) The condition of the periodontal ligament is another crucial factor. The periodontal ligament plays a fundamental role in the revascularization and reattachment of the tooth to the alveolar bone. Damage to the PDL during tooth extraction or prolonged extraoral time may compromise the success of the transplant (2). Studies suggest that teeth with an intact, healthy PDL have higher survival rates after transplantation than those with a damaged or necrotic PDL (5). 4) Surgical technique and post-operative care Correct surgical technique is essential for the success of tooth autotransplantation. Ensuring minimal trauma to the periodontal ligament, the correct position of the donor tooth and effective splinting are essential steps in achieving positive outcomes (1). Post-operative care, which includes the use of antibiotics, pain management and regular follow-up visits, is equally crucial in preventing complications such as infections, root resorption or tooth loss (4). Complications of tooth autotransplantation While tooth autotransplantation has a high success rate in many cases, it can cause some complications. The most common problems include: Root resorption is a significant concern after transplantation and can lead to tooth loss (7). The early identification of root resorption and appropriate management, such as radiographic imaging monitoring, are crucial in preventing long-term complications. Ankylosis is another potential complication, especially when there is excessive damage to the periodontal ligament or if the tooth is not positioned correctly in the recipient site. Future possibilities Recent advances in regenerative medicine and tissue engineeringoffer promising opportunities to improve the outcomes of tooth transplantation. Techniques such as the use of stem cells and biomaterial scaffolds forperiodontal ligament regeneration could improve healing and revascularisation of transplanted teeth (3). Furthermore, the development of advanced imaging techniques for pre-operative planning and post-operative monitoring could enable more precise surgical interventions, leading to better long-term outcomes. In conclusion, tooth autotransplantation appears to be a promising and interesting technique, especially in young patients with healthy donor teeth. The success of the procedure depends on several factors, including the patient’s age, the type of tooth, the health of the periodontal ligament (PDL) and the surgical technique. Despite potential complications such as root resorption and ankylosis, with proper management autotransplantation can be a viable alternative to conventional prosthetic options. Further research into regenerative approaches and surgical advancements will likely continue to improve the success rates and clinical outcomes of this procedure.
Classification of dental cements for dental prostheses
There are several types of dental cement on the market. The first distinction to be made is certainly between endodontic cements and cements for dentures (1). Endodontic cements are used in endodontics for filling root canals while cements for dentures are used to cement prostheses to teeth (1,2). Focusing on the latter, it is worth mentioning that the first cements for prostheses were not adhesive cements, neither for the tooth nor for the prosthesis material, but they adequately filled the space at the tooth-restoration interface, creating a strong micromechanical retention between the two surfaces, thus preventing dislocation of the prosthesis (1,2). The current cements for dentures (permanent) involve the use of adhesive techniques, based on the creation of a solid layer that serves both as micromechanical retention and as adhesion to the substrates in order to improve denture retention (3). Classification of dental cements for dentures by material Dental cements for dentures can be classified in different ways based on: the type of material, chemical reaction for setting or according to the formulation and reaction compounds (2). In this article, based on the type of material, we will classify them into: Zinc oxide-eugenol cements Zinc oxide-eugenol cements are supplied in liquid-powder or paste-paste form and are mostly used in temporary cementing of provisional restorations (2). In fact, their properties of low compressive strength, low pH and significant solubility in watery environments do not make them suitable for permanent cementing (4). To strengthen these cements, acrylic resins and alumina fillers have been added, but they are still less resistant than zinc phosphate cements and glass ionomers (5). Zinc oxide-eugenol cements should be used with caution under composite restorations since eugenol may inhibit resin polymerisation (1). However, the presence of eugenol makes these cements bacteriostatic and provides a fairly sedative effect on dental pulp, which, over the years, has made them the material of choice for filling the pulp chamber following pulpotomies or pulpectomies in primary dentition (4). Zinc phosphate cements Zinc phosphate cements are generally supplied in powder-liquid form; this powder contains zinc oxide (and, to some extent, magnesium oxide) and the liquid contains phosphoric acid and water. These cements are manually mixed using a small spatula and their acid-base reaction is strongly exothermic and influenced by the powder-liquid ratio, temperature and the presence of humidity (6). These were the first cements to be used in dentistry for the permanent cementation of crowns and bridges, whether cast or metal-ceramic, since they offer adequate retention and mechanical strength, although they form no chemical bond either with the abutment or the prosthetic materials (7). Polycarboxylate cements Zinc polycarboxylate cements, unlike zinc oxide cements, are able to form a chemical bond with enamel and dentin, by binding calcium ions to the acid groups of the polyacrylic acid chains (2). These cements are also supplied in a powder-liquid form to be mixed manually with non-metallic spatulas, as they form strong bonds with stainless steel (1). Rapid mixing is strongly advised for these cements, since polycarboxylates become thinner as the cutting speed increases, with a consequent reduction in cement viscosity, which helps to ensure easy insertion into the inner surface of the prosthesis (2). It is also essential to allow for the setting time (3-6 minutes) and use the cement before it loses its “glossiness”, as the shiny surface indicates the presence of free carboxylic groups on the surface, in order to obtain a good bond with the abutment (2). They are used in the same way as zinc phosphate cements. Glass ionomer cements Glass ionomer cements are made polyacrylic acid, silica, alumina and fluorite. They are marketed in several forms, but the most common are the powder-liquid forms; the powder is made up of the glassy portion of the cement in which silica, alumina and fluorite are incorporated, while the liquid is composed of polycarboxylic acid (1). Glass ionomer cements chemically bind to the mineralised tissues of teeth by chelating acrylic acids to the organic and inorganic components of the tooth, and they continue to polymerise even after the setting time (1,2). In fact, the mechanical properties of these cements are initially low but they improve over time in order to create a cement with high tensile and compressive strength also due to its low viscosity that allows it to penetrate into all the smallest cracks of the surfaces it comes into contact with (micromechanical retention) (8). The ability to release fluoride ions over time in the surrounding environment is a distinctive feature of these cements, which are therefore also useful in the prevention of tooth decay (1,2,8). Resin-modified glass ionomer cements They are also known as “glass ionomer hybrid” cements, and can be chemically polymerised, with light or in both ways, and the acid-base reaction of the glass ionomer occurs simultaneously with polymerisation (2). These are also available in powder-liquid formulations, where the powder contains glassy fluoro-aluminosilicates and one or more primers such as camphorquinone, while the liquid is a water solution of polyacrylic acid, HEMA and methacrylate. Their reaction rate is much slower compared to conventional glass ionomers because the formula contains less water, but the bond to the dental tissue is still due to the interaction of calcium with polyacrylate (2). Compared to conventional glass ionomers, these cements have been shown to have higher bond strength (9); however, this seems to be due more to a better micromechanical fit of the cement with the micro-cracks on the tooth surface rather than to the development of a resinous hybrid layer that infiltrates the dentine tubules (10). Nevertheless, the presence of methacrylate results in greater polymerisation shrinkage of these cements and the small amount of water and carboxylate results in less adhesion to the dental structure of the cements, which are therefore more likely to suffer from micro-infiltrations compared to glass ionomers (11). Compomers Compomers are composites modified with polyacids, built by incorporating glass ionomer cement particles into the resinous matrix (2). They are generally supplied in a single light-curing or self-curing paste or as a dual product, and powder-liquid formulations are also available. They are moisture-sensitive cements and absorb water from saliva, which triggers the slow acid-base reaction of the glass ionomer particles with the carboxylate, which leads to the release of fluoride (12). However, this process reduces the compressive and bending strength of the material (13). Adhesion to the dental tissue is
Traumatic dental injuries: classification and first aid guidelines
Trauma represents a significant moment of stress and agitation for anyone when it occurs, both for the person who suffers it and for the people who witness the event and who are able to rush to their aid. When the trauma affects the face, there is also the added concern that aesthetic damage has been suffered. In terms of traumatology, teeth play a key role as they are in a position which is very sensitive to impact, protected only by the reduced thickness of the soft tissues of the lips. They are also made of a crystalline material such as hydroxyapatite, which is extremely hard but fragile. At an epidemiological level, although the mouth area represents only 1% of the total body area, 5% of all injuries are concentrated there; this figure increases when speaking of preschool children, accounting for as much as 17% of all traumas. (1) Traumatic dental injuries in the pediatric population In terms of oral traumatic injuries, teeth are involved in 92% of cases. (1) The incidence rate in children is estimated between 1% and 3%. (2) This rate decreases with increasing age and boys are affected more. (3,4) The prevalence of these injuries in primary dentition is around 30%. (5,6) On the other hand, an extensive American survey has demonstrated that one in four adults shows signs of trauma on the incisors. (7) Nowadays, in the most developed countries, thanks to active primary prevention measures, the incidence of caries has greatly decreased, making traumatic injuries a greater problem in percentage terms than they once were. (2) This type of accident is very common: knowing what action to take is essential to be able to limit the damage to a minimum and, above all, not make the situation worse. Traumatic dental injuries in children: first aid measures The first essential point is to understand whether we are dealing with a permanent or a deciduous tooth. This primary survey will in fact completely change the approach to the intervention. (8-10) In the vast majority of cases, trauma affects the upper front teeth: the central and lateral incisors. (11) The replacement of central and lateral incisors occurs between the ages of 6 and 8. Following the provision of first aid, a thorough dental examination always needs to be performed, which includes any necessary records, the correct therapy and the drafting of a follow-up that allows the course of the clinical situation to be monitored over time. We will now look at what first aid measures to take, not in a dental surgery, depending on whether a deciduous or permanent tooth is involved. (8-10) Interventions for traumatic injuries affecting deciduous teeth First of all, when we are faced with a trauma involving a deciduous tooth, we must always consider that the apex, in relation to the age of the child, will probably be close to the follicle of the permanent tooth. Therefore, maximum awareness and attention are required so as not to risk damaging the permanent tooth in this delicate phase of its formation. Generally speaking, it is therefore risky to perform repositioning manipulations on a deciduous tooth because we could traumatise the permanent follicle, compromising its natural development. If the trauma has resulted in a fracture, it is advisable to preserve the fragment (if it has been found) so that it can be assessed and possibly glued back once a precise diagnosis has been made and the clinical situation has been understood in detail. It is therefore not advisable during first aid to put a deciduous tooth back immediately. We should rather gain a precise understanding of the situation, taking into account the extent of the extrusion, the mobility, the root formation and the child’s cooperation before carrying out any manipulation. If the trauma has caused the complete avulsion of the deciduous tooth, its reinsertion is never recommended under any circumstances. Traumatic injuries affecting permanent teeth If the trauma has affected a permanent tooth, just as in the case of a deciduous tooth, it is important to try to find the fragment, which can be cleaned and glued back using adhesive procedures once in the dental surgery. If the trauma has caused a fracture and the coronal fragment is mobile but still in situ, it must be stabilised as much as possible during the emergency intervention, even simply by pulling a handkerchief tightly between the teeth until a more definitive treatment plan is reached, which will probably include flexible splinting for some time. Following a root fracture, if the coronal fragment is not in the correct position but is still inside the socket, it must be repositioned as soon as possible. Once at the dental surgery, after checking the position radiographically, it is possible to proceed with splinting the tooth. Even in the case of more extensive alveolar fractures, it is always advisable to reposition the alveolar fragment and splint it as soon as possible. If there is no fracture but the tooth has suffered a simple concussion or a subluxation, no special first aid attention is required. If, on the other hand, the permanent tooth has undergone an extrusive luxation (it appears longer, from a clinical standpoint), it must be repositioned by gently reinserting it in the socket. It will then need to be splinted at a later stage. If the luxation also has a vestibular vector, the tooth will have to be repositioned manually, then stabilised once in the dental surgery. If the luxation is intrusive (the tooth re-enters the alveolar bone axially, appearing shorter), it will not be possible to perform any emergency manipulation, in which case the situation will have to be monitored over time, while adopting the right treatment option. Complete avulsion of a permanent tooth What action should be taken in the case of complete avulsion of a permanent tooth? (10) After finding the avulsed tooth and verifying that it is a permanent tooth, be sure to hold it by the crown without touching the root. If the tooth is dirty, it should be rinsed briefly under running water (10 seconds at most) and reinserted in place. Once reinserted, have the patient bite on a