Principles of Tooth Preparation

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Teeth do not possess the regenerative ability found in most other tissues. Therefore, once enamel or dentin is lost as a result of caries, trauma, or wear, restorative materials must be used to reestablish form and function. Teeth require preparation to receive restorations, and these preparations must be based on fundamental principles from which basic criteria can be developed to help predict the success of prosthodon-tic treatment. Careful attention to every detail is imperative during tooth preparation. A good preparation will ensure that subsequent techniques (e.g., provisionalization, impression making, pouring of dies and casts, waxing) can be accomplished.

The principles of tooth preparation may be divided into three broad categories:

1. Biologic considerations, which affect the health of the oral tissues

2. Mechanical considerations, which affect the integrity and durability of the restoration

3. Esthetic considerations, which affect the appearance of the patient

Successful tooth preparation and subsequent restoration depend on simultaneous consideration of all these factors. Often improvement in one area will adversely affect another, and striving for perfection in one may lead to failure in another. For example, in the fabrication of a metal-ceramic crown (see Chapter 24), sufficient thickness of porcelain is necessary for a lifelike appearance. However, if too much tooth structure is removed to accommodate a greater thickness of porcelain for esthetic reasons, the pulpal tissue may be damaged (biologic consideration) and the tooth unduly weakened (mechanical consideration). An in-depth knowledge and understanding of the various criteria are prerequisites to the development of satisfactory tooth preparation skills. Predictable accomplishment of optimum tooth preparation (Fig. 7-1) often entails finding the best

Principles Tooth Preparation

Fig. 7-1. The optimum restoration should satisfy biologic, mechanical, and esthetic requirements.

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Fig. 7-1. The optimum restoration should satisfy biologic, mechanical, and esthetic requirements.

combination of compromises among the prevalent biologic, mechanical, and esthetic considerations.

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