**3. Prosthodontic solutions in completely edentulous patients**

Toothless residual alveolar ridges in edentulous patients imply the construction of retentive and stable conventional complete dentures [17]. Unfortunately, this can only *Implant-Retained Maxillary and Mandibular Overdentures - A Solution for Completely… DOI: http://dx.doi.org/10.5772/intechopen.99575*

be achieved in favorable oral conditions that mostly apply to the satisfactory edentulous ridge form and height affecting stability and retention of the dentures in function [18, 19]. It has already been proved that ill-fitting conventional complete dentures can compromise patient's oral function and therefore cause psychosocial problems and decrease his/her oral health-related quality of life (OHRQoL) [20, 21]. The most often recorded complains among conventional complete denture wearers are pure or fair chewing ability, mostly within the subjects who had lost more than 50% of their estimated original ridge height, correlating the residual ridge resorption with worsening of the complete denture stability during mastication [22, 23].

## **4. Implant prosthodontics**

In the last few decades, implants have been increasingly introduced in prosthodontics to replace patient's tooth/teeth lost for several reasons including trauma, caries, and periodontal disease as one of the main causes of edentulism occurring in the elderly population [24]. The loss of single, several or even all the teeth in the jaws can be compensated by placing one or more implants and constructing fixed or removable prosthodontic restorations on them [25–30].

A large number of risk factors related to the implant-prosthodontic therapy are listed in the literature, both at the level of implants as well as of implant prosthodontic restorations [31–34]. It has already been proved in many studies that poorer bone quality and lack of bone volume may be the one of the main reasons of implant failure [35]. Therefore, numerous classifications assisting the therapist in determination of the proper implant-prosthodontic therapy have been suggested for assessment of the degree of atrophy of edentulous jaws, among which the classification system for jaw bone shape and quality proposed by Lekholm and Zarb in 1985 is very often used [36]. One of the major problems in elderly population certainly is the lack and poorer quality of bone structure (Lekholm and Zarb quality 3 or 4 and quantity C, D, or E), especially in the distal part of the alveolar ridges, offering a great challenge for the placement of multiple implants or immediate implant loading and fixed implant prosthodontic constructions [37, 38]. Therefore, in these patients, having compromised bone conditions, implant-retained overdentures may be the best solution [39].

## **5. McGill consensus statement on overdentures**

With an increase of the life expectancy in the following years an increased number of completely edentulous patients will visit dental offices [40]. With a higher standards of their life quality they will expect the same level of standards in prosthodontic treatments demanding improvement in the oral health quality of life, too [40]. With conventional complete dentures relying upon resorbed residual bone ridges of maxilla and mandible and overlying mucosal soft tissues satisfactory retention and stability of the dentures is usually not possible to achieve. Therefore, it is up to the prosthodontics to find new solutions to this issue.

In May 2002, at McGill University in Montreal, Canada, prosthodontic symposium was held where numerous relevant experts who worked in the field of removable prosthodontics stated that the current available evidence suggested the restoration of the completely edentulous mandible using conventional complete denture is no longer the first choice in prosthodontic treatments and instead it should be a

two-implant overdenture, regardless of the type of attachment system used (bar, ball or magnet) [41, 42]. According to the available literature patients find mandibular implant-retained overdentures to be superior over conventional ones in retention, ability to chew and speak, comfort, and satisfaction and in oral health related quality of life [43–46]. In April 2009. In York, UK a further consensus statement created by members of British Society for the Study of Prosthetic dentistry Council was released highlighting that uptake by dentists of implants for completely edentulous patients has still been rather slow [47].

As it is stated in the Consensus Statement, the solution in completely edentulous patient should be maxillary conventional complete denture and mandibular two implant-retained overdenture and this therapy presents a minimum standard that should be sufficient for the most patients, taking into account patient comfort and satisfaction, costs and both clinical and dental laboratory time [41, 47]. According to the Statement, placement of only two implants increases the total cost of the treatment, but it is still low enough (in comparison to the multiple implant-prosthodontic restorations) to be affordable to most edentulous patients [41].
