**9. Prosthodontic maintenance of different implant-retained overdentures**

Prosthetic complications with implant-retained overdentures are unavoidable and are mostly mechanical [84]. Compared with conventional complete dentures there is a higher rate of repair and replacement of this type of dentures, mostly regarding their design and type of the attachment system [84].

In cases where implant retained overdenture is not reinforced by the metal framework higher rate of acrylic fractures must be expected, especially in the cases where the patrix size of the attachment system is relatively too large [85].

Different attachment systems require different care. It has been proven that rigid bars connecting 4 implants show lower incidence rate of maintenance such as clip activation or resolving the fracture, than resilient system such as round bars most likely because of its inability to rotate around the fulcrum line during the function [86]. The data also demonstrates an increase in prosthodontic maintenance for ball attachments related to the wear or fracture of the ball head or need for activation of the ball matrix or relining of the denture [87, 88].

Numerous authors reported different types of matrix repairs, too, such as clip fractures or clip activation in the period of 5 years, most commonly in the first year [89, 90].

Furthermore, the longevity of the implant retained overdenture depends on maintaining oral and denture hygiene, as well as frequency of use. It is clear that simpler constructions, away from mucosa, are easier to maintain and clean, such as balls and locators in comparison to the bars, especially if they are in the close relationship with the mucosa [91]. Nocturnal use of this type of dentures has also showed higher

**Figure 17.** *4 implant-retained maxillary overdenture follow-up protocol.*

*Implant-Retained Maxillary and Mandibular Overdentures - A Solution for Completely… DOI: http://dx.doi.org/10.5772/intechopen.99575*

incidence of stomatitis due to the excellent retention, less saliva produced and more bacteria to develop in that environment [92].

It is necessary to emphasize that the prosthodontic complications can be reduced to an expected level if a close follow-up protocol is applied (**Figures 17** and **18**).

#### **Figure 18.**

*4 implant-retained mandibular overdenture follow-up protocol.*

#### **Figure 19.**

*Appearance of 4 implant-retained maxillary and mandibular overdentures - frontal and both lateral views.*

**Figure 20.** *Portrait view of the patient with 4 implant-retained maxillary and mandibular overdentures in occlusion and in smile.*

We must also not forget that ultimate goal of producing implant-retained overdentures is patient's satisfaction not only with the esthetics but also with the longterm function of the removable prosthodontic restoration (**Figures 19** and **20**).

## **10. Conclusion**

Implant-retained overdentures are very attractive implant-prosthodontic treatment because of its relative simplicity in construction and design, easy handling, minimal invasiveness and lower costs. They are particularly suitable to maintain facial support and achieve higher level of esthetics with denture acrylic material when moderate to extreme alveolar ridge resorption is present in patient's mouth, mainly in the older population. It is very important to emphasize that the implant-retained overdentures are supported by both implants and denture underlying soft tissue and therefore fewer implants are requested compared to the prosthodontic restorations supported only by implants.

This type of overdenture is usually connected with two or four implants, depending on which jaw is involved and on quality and quantity of the residual bone structure. These implants are mainly placed within the alveolar bone on the opposite sides of the completely edentulous arch and connected to the complete denture using different correspondent coupling units placed on the tissue surface of the prosthodontic restoration. When implant and denture attachments are appropriately connected, the complete denture is held in position over the denture bearing area and both implants and mucosa provide support, retention and stability in function. The main advantage of this type of implant-prosthodontic solution over fixed one is that the implant-retained overdenture can be easily removed and cleaned (easy access to both the denture and the implants'

*Implant-Retained Maxillary and Mandibular Overdentures - A Solution for Completely… DOI: http://dx.doi.org/10.5772/intechopen.99575*

abutments) and therefore provides better oral hygiene and may affect greater longevity of the restoration itself.

The results of this systematic review indicate the superiority of implant-retained overdentures when compared to conventional complete dentures in fully edentulous patients suffering from moderate to severe alveolar bone resorption with regards to efficacy, patients' satisfaction and quality of their life.
