Prosthodontics (replacement of missing teeth)
Prosthodontic treatment comprises procedures used to replace already missing teeth, including the replacement of dental crowns on dental implants. The restorations are primarily fixed prosthetic restorations (crowns, bridges, inlays and onlays, aesthetic veneers), which the patient cannot and must not voluntarily remove from the oral cavity. These restorations are aesthetic, immobile and highly functional. If the anatomical and other conditions in the mouth do not permit the fabrication of fixed prosthetic restorations, removable prosthetic restorations are used (partial and complete dentures), which the patient can remove from the mouth by themselves when necessary. They are characterised by simplicity and uncomplicated fabrication, but at the expense of poorer stability and consequently reduced comfort.
Dental prosthodontics is a branch of dental medicine concerned with the replacement of missing teeth. The science has its roots in previous centuries, when people replaced teeth using natural materials, particularly wood and metals. The principles of replacement have not changed significantly over time; understandably, they have always pursued the same objective: to replace a missing tooth.
Evolutionary facts teach us that, in the past, tooth loss was closely associated with human death. Nature has therefore given us teeth that are strong, resistant and extremely well innervated, so that intense painful stimuli constantly warn us of current disorders, overloading and disease. Dental diseases leading to tooth loss began to occur mainly with changes in dietary habits, while tooth replacement technology simultaneously developed into today’s approach, which our ancestors probably could not even have imagined.
Today, we know two basic approaches to replacing missing teeth: removable and fixed prosthodontics. The names themselves indicate the principles by which a prosthetic restoration is retained in the mouth. When discussing removable prosthodontics, two main restorations should be mentioned: the removable partial denture and the removable complete denture.
These restorations are suitable for dental conditions in which the patient has few or no natural teeth. They are also used when the distribution of abutments is unfavourable and does not permit a fixed prosthetic restoration. Dentures may be entirely acrylic, meaning that they are made from long synthetic polymer molecules that bond into a durable, attractively coloured, lightweight plastic material, or they may be reinforced with very strong metals that form a cast metal base, making the denture stronger and allowing partial dentures to be attached to the remaining abutment teeth much more effectively. The denture is attached to the existing teeth with cast clasps, precision attachments or joints (anchors), or with conical crowns. These retain the denture in the mouth in the best possible way and provide the most aesthetic removable prosthetic solutions.
Dental prosthodontics is a branch of dental medicine concerned with the replacement of missing teeth. The science has its roots in previous centuries, when people replaced teeth using natural materials, particularly wood and metals. The principles of replacement have not changed significantly over time; understandably, they have always pursued the same objective: to replace a missing tooth.
Evolutionary facts teach us that, in the past, tooth loss was closely associated with human death. Nature has therefore given us teeth that are strong, resistant and extremely well innervated, so that intense painful stimuli constantly warn us of current disorders, overloading and disease. Dental diseases leading to tooth loss began to occur mainly with changes in dietary habits, while tooth replacement technology simultaneously developed into today’s approach, which our ancestors probably could not even have imagined.
Today, we know two basic approaches to replacing missing teeth: removable and fixed prosthodontics. The names themselves indicate the principles by which a prosthetic restoration is retained in the mouth. When discussing removable prosthodontics, two main restorations should be mentioned: the removable partial denture and the removable complete denture.
Conventional acrylic upper complete denture. Adhesion prevents the denture from falling out of the mouth. The stability and therefore the functionality of the denture depend primarily on the shape of the supporting surface, namely the hard palate and the alveolar ridges. A deep, Gothic-shaped palate and undercut areas provide greater stability of the restoration.
These restorations are suitable for dental conditions in which the patient has few or no natural teeth. They are also used when the distribution of abutments is unfavourable and does not permit a fixed prosthetic restoration. Dentures may be entirely acrylic, meaning that they are made from long synthetic polymer molecules that bond into a durable, attractively coloured, lightweight plastic material, or they may be reinforced with very strong metals that form a cast metal base, making the denture stronger and allowing partial dentures to be attached to the remaining abutment teeth much more effectively. The denture is attached to the existing teeth with cast clasps, precision attachments or joints (anchors), or with conical crowns. These retain the denture in the mouth in the best possible way and provide the most aesthetic removable prosthetic solutions.
A precision attachment or joint that retains a removable partial denture. In this case, the abutment teeth are restored with fixed prosthetic restorations, namely metal-ceramic crowns. The crowns carry the attachment, which fits precisely into an element incorporated into the removable denture reinforced with a metal base. In this way, the denture is retained relatively very securely on the abutment teeth, and metal components (clasps or hooks) are not required. The denture therefore also meets more demanding aesthetic criteria.
A cross-section of a precision attachment or joint, shown on a plaster working model and used to retain complete dentures. One part of the joint is mounted on the tooth root, while the other is mounted on the lower surface of the complete denture. This method is used when only a small number of roots remain. In this case, the roots are subjected to less torque because they are predominantly exposed only to vertical forces parallel to their longitudinal axis.
Schematic illustration of the attachment of a removable restoration to a gold conical crown. The gold primary cone is permanently cemented onto the prepared existing abutment tooth. The white line in the diagram shows the contact between the gold primary cone and the metal-ceramic removable restoration. The precise fit of the dark metal framework on the gold cone produces a strong frictional force that retains the artificial teeth on the abutment teeth. The patient can remove the restoration when necessary.
In terms of occlusal comfort and aesthetic solutions, fixed prosthetic restorations greatly surpass removable ones. Dental crowns and their derivatives, dental bridges, are the most common ways of restoring incomplete dentitions. Of course, they can be used when the number and distribution of the patient’s own abutment teeth are favourable. The materials used for such restorations have been known for a very long time: metals and ceramics.
Cross-section of a metal-ceramic crown or cap. The metal coping, which is in contact with the prepared tooth, bears the biting forces. Ceramic is applied to the metal, giving the tooth a natural appearance, exceptionally high hardness, smoothness, lustre and a pleasant feel to the touch.
Metal framework of a bridge restoration during processing.
Final processing of a metal-ceramic bridge restoration with diamond polishing burs.
The metals should be noble or semi-noble, as their precisely defined structure determines the extremely important coefficients of thermal expansion of the restorations, which affect their durability. Fabrication technology has reached its peak in the production of all-ceramic crowns and aesthetic veneers, whose precision can rival the manufacture of microprocessors and aerospace technology.
An all-ceramic crown contains no metal in its core. The crown or missing tooth in a bridge restoration is made entirely of ceramic material. The metal core is most commonly replaced by zirconium oxide, which is exceptionally strong. Ceramic is applied to the zirconia framework and performs a similar function to that in metal-ceramic restorations. Unlike metal-ceramic restorations, all-ceramic restorations transmit light and are therefore very similar to natural dental tissues. The aesthetic result is outstanding.
Recently, the dream of a third generation of teeth has begun to come true, although they do not yet grow by themselves. Dental implants allow us to place “artificial roots” in human bone, enabling patients with complete dentures to receive fixed prosthetic restorations or bridges. The loss of a smaller number of teeth does not require the fabrication of bridge restorations, but rather individual dental crowns placed directly on dental implants. This approach extends the boundaries of prosthodontics towards substantially better retention of prosthetic restorations, preservation of the patient’s own tooth structure and consequently longer-lasting occlusal comfort.
Schematic illustration of the retention of a removable lower complete denture using an attachment mounted on two implants. The patient can remove the denture when necessary, while the implants with attachments prevent unwanted movement and displacement of the denture.
Schematic illustration of the retention of a removable lower complete denture using an attachment mounted on two implants. The patient can remove the denture when necessary, while the implants with attachments prevent unwanted movement and displacement of the denture.
Method of attaching a fixed bridge restoration to dental implants with lateral screws (on a working model). In this case, the patient cannot remove the restoration at will. The restoration is completely immobile and stable in the mouth despite the absence of natural teeth. Functional and aesthetic rehabilitation is complete.
✦ This content was translated from the original with the assistance of an AI translation system.