口腔学英文课件：Principles of Tooth Preparation

Causes of injury
• Temperature • Chemical action • Bacterial action
• Great care is needed to protect the tongue when the lingual surfaces of mandibular molars are being prepared.
Pulp
• Great care also is needed to prevent pulpal injuries during fixed prosthodontic procedures, especially complete crown preparation. Pulpal degeneration that occurs many years after tooth preparation has been documented. Extreme temperatures, chemical irritation, or microorganisms can cause .
• So the technique of tooth preparation must avoid and prevent damage to the adjacent tooth surfaces.
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Soft tissues
• Damage to the soft tissues of the tongue and cheeks can be prevented by careful retraction with an aspirator tip(吸唾管), mouth mirror or flanged saliva ejector.
Prevention of Damage during Tooth Preparation
Adjacent teeth
• Damage in Adjacent teeth is easier to dental caries than was the original undamaged tooth surface.
• 2. Mechanical considerations, which affect the integrity and durability of the restoration.
• 3. Esthetic considerations, which affect the appearance of the patient.
Principles of Tooth Preparation
(牙体预备的原则)
preface(前言)
1. Reasons of dental defects or dentition defects: caries, trauma, or wear... 2. Restorative materials must be used to reestablish form and function. 3. Teeth require preparation to receive restorations, and these preparations must be based on fundamental principles from which basic criteria can bedeveloped to help predict the Success of prosthodontic treatment. 4. Careful attention to every detail is imperative during tooth preparation.A good preparation ensures that subsequent techniques (e.g., interim fabrication, impression making, pouring of dies and casts, waxing) can be accomplished.
BIOLOGIC CONSIDERATIONS
• Surgical procedures involving living tissues must becarefully executed to avoid unnecessary damage.The adjacent teeth, soft tissues, and the pulp of the tooth being prepared are easily damaged in tooth preparation.
The principles of tooth preparation may be divided into three broad categories:
• 1. Biologic considerations, which affect the health of the oral tissues.
• enamel • dentin • pulp
• Tooth preparations must account for the structure of the dental pulp chamber. Pulp size, you can do an X-ray film before.Decreases with age, Up to about age 50, it decreases more .
• If poor preparation leads to inadequate marginal fit or deficient crown contour, plaque control around fixed restorations becomes more difficult. This impedes the long-term maintenance of dental health.