Lino Calvani - Fundamentals of Treatment Planning

The outcome of all of this evidence-based science and practice is a number of clinical and laboratory therapeutic prosthodontic tools available on the market today. These tools are intended for practical therapeutic solutions capable of restoring oral esthetics and function in patients whose mouths are in need of restoration.

As it is impossible to outline here all the clinical and laboratory prosthodontic reconstructive tools and procedures in use today, this chapter looks at the main categories of tools currently available to show the most common prosthodontic esthetic and functional rehabilitative possibilities, as reported in the literature.

Aims and requirements of all prostheses

The following are the main rehabilitative goals of any prosthesis. It should:

● replace the lost dentition and improve on it as much as possible;

● satisfy the patient’s needs/desires/requests;

● guarantee the patient’s comfort;

● help to prevent further problems;

● improve the patient’s oral health;

● help to give the patient a better quality of life.

To achieve these goals, the prerequisite of all prostheses should be that they:

● are minimally invasive;

● protect the remaining dental and periodontal structures;

● are made from biocompatible materials;

● are esthetically, phonetically, and functionally effective;

● are accessible to excellent oral and dental hygiene;

● are simple and easily repairable;

● last as long as possible;

● cost the least amount of money.

Current main prosthodontic tools

Table 3-1outlines the main categories of prosthodontic tools in use today. This should be seen in light of the recent progress that has taken place in the prosthodontic field due to the modern technological revolution.

Table 3-1 Outline of the most important prosthodontic tools currently in use today

Fixed restorations

1. Inlays, onlays

2. Veneers

3. Crown, bridges, post and cores

4. Full-arch fixed complete prostheses

Removable partial dentures

1. Tooth-borne prostheses

2. Tooth- to mucosa-borne prostheses

Complete dentures

1. Immediate prostheses

2. Final prostheses

Overdentures

1. On some remaining portion of roots

2. On well-positioned implant

Fixed implant-retained prostheses

1. Partial implant prostheses

2. Following the prolonged use of complete dentures (CDs)

3. Following extractions, immediate CDs, and delayed implant placement

4. Following extractions and immediate implant placement

Bioinformatics and digital prosthodontic tools

1. Computer-aided implantology

2. Computer-aided prosthetic designing and planning

3. Precise guided implant positioning

Fixed restorations

Fixed prostheses such as crowns and bridges are termed fixed partial dentures (FPDs) or fixed complete dentures (FCDs), depending on their extension and abutment involvement. 2

Fixed prostheses are considered a dream tool for prosthodontists because they are the best and most natural restorations. 3The naturalness of the final result depends on a number of clinical and technical factors such as laboratory materials, technical possibilities, professional skills, and artistic dexterity. 4- 8Fixed prostheses are used all over the world and are fabricated from various materials, including gold, depending on factors such as culture and esthetics. 5, 9Their manufacture follows rules imposed by ongoing research, especially that which is occurring in the field of digital technology.

The use of fixed restorations for endodontically treated teeth depends on the amount of the remaining tooth structure and on well-established principles of tooth preparation. 5, 6, 8, 10- 12, 19Even though great improvement has taken place in this respect with resin adhesive rehabilitations, 11- 13cast post and cores still show superior physical and biomechanical capabilities to withstand vertical and lateral loads as well as decementation. 5, 6, 8, 12, 14- 25

Nowadays, other new fixed prosthodontic methods, born as a result of and crafted with the help of new digital technologies, are revolutionizing the clinic and laboratory. And this is just the beginning, as much more is expected with the current speed of exponential progress and growth in this field. 26

Today, in the case of edentulism where there is one or more missing teeth, implants are usually considered as the first option during treatment planning for fixed restorations, unless physical, biological, biomechanical, psychologic or economic limitations and/or contraindications are present. 27- 33Where implants are not indicated due to their negative biological, functional, and esthetic possibilities or the chance of predictable short- or long-term complications, 34tooth-borne FPDs and FCDs are considered the secondary restorative tool, with pontic elements replacing the edentulous areas.

Removable partial dentures

Removable partial dentures (RPDs) are generally considered the third restorative option in the western world. However, in many other countries worldwide they are considered to be the first choice. RPDs can be very helpful in various partially edentulous cases, depending on the patient’s chief complaint, desire, and financial situation. 35- 37The relatively lower cost of these prostheses is a major factor of choice, despite the difficulty in planning them biomechanically and the inevitable clinical limitations that their unnatural composite structure introduces into the masticatory environment. 38- 48This fact should spur us on to deliver a biomechanically well-conceived project in order not to damage the remaining dentition and to preserve it for as long as possible.

Complete dentures

Due to decades of success and their helpfulness in innumerable edentulous cases, CDs have been called the mother of all dental prostheses. 49According to studies on oral health in the USA, even though there has been a relative decline in complete edentulism over the past 30 years due to a corresponding decline in caries, the need for complete dentures to treat edentulism is still high due to the increase in the aging population. 28, 50Furthermore, edentulism still depends on infectious disease conditions and related health problems that involve both the young and the elderly worldwide, even today. 51

Although there is a large body of scientific literature about them, clinical experience shows that in many instances CDs still remain very difficult to create and craft properly. However, if the literature is carefully studied and scientific engineering rules are strictly followed, the construction of CDs can result in a successful restoration. Experience shows that the obvious weakness in these prostheses is their mobility. 52, 53In this respect, they must necessarily rely on the remaining available maxillary and mandibular primary and secondary bearing areas and on the characteristics of the hard and soft tissue comprising these areas. Their success also relies on a number of other biological, physical, chemical, and subjective factors that have been widely described in the literature. Regardless of whether they are created in an analog or digital manner, the nature of CDs makes these prostheses biomechanically lacking in terms of stability, retention, and support compared with other fixed prostheses. Nevertheless, many patients lack the economic resources for fixed implant treatments, and many in fact do live with CDs satisfactorily and sometimes more than satisfactorily, which compensates for their biologic limitations. 52- 70

In cases where up-to-date, three-dimensional (3D) digital technologies can be used to virtually plan the rehabilitation of edentulous cases with immediate implant-supported fixed prostheses, CDs can be used as excellent interim prostheses, as useful verification jigs, and as surgical guides to position implants properly to recreate final full-arch implant restorations.