Dental Assistant Skills: Tooth Structures and Tissues

1. Chapter 19 Dental Assistant Skills

2. 19:1 Identifying the Structures and Tissues of a Tooth • Odontology • Study of anatomy, growth, and diseases of teeth • Teeth are accessory organs of the digestive tract • Teeth aid in mastication (chewing) of food

3. 19:1 Identifying the Structures and Tissues of a Tooth (continued) • Dentitions: sets of teeth • Primary or deciduous dentition • 20 teeth • Permanent or succedaneous dentition • 32 teeth

4. 19:1 Identifying the Structures and Tissues of a Tooth (continued) • Crown • Visible in the mouth, protected by enamel • Root • Below the gum line, covered on the outside by cementum

5. 19:1 Identifying the Structures and Tissues of a Tooth (continued) • Cervix • Where crown meets cementum covering the root • Apex • Tip of the root • Apical foramen, where nerves and blood enter tooth

6. 19:1 Identifying the Structures and Tissues of a Tooth (continued) • Tissues (refer to Figure 19-2 in Text) • Enamel: hardest body tissue, covers the crown • Cementum: covers outside of the root • Dentin: main bulk of tooth, located under the enamel and cementum of the root • Pulp: soft inner area of tooth

7. 19:1 Identifying the Structures and Tissues of a Tooth (continued) • Periodontium • Structures that surround and support teeth • Alveolar process or ridge: surrounds roots and has sockets • Periodontal ligament: supports tooth in the socket • Gingiva or gums: surrounds the cervix

8. 19:1 Identifying the Structures and Tissues of a Tooth (continued) • Disease can affect the teeth and supporting structures • Dental care • Preventing and treating dental disease • Preserving and prolonging the life of the teeth

9. 19:2 Identifying the Teeth • Incisors • Front and center of the mouth • Used to cut or bite food • Cuspids • At angles of lips, also called canines or eyeteeth • Used to tear food

10. 19:2 Identifying the Teeth (continued) • Bicuspids • Before the molars, also called premolars • Used to pulverize or grind food • Molars • Back of the mouth; largest, strongest teeth • Used to chew and grind food

11. 19:2 Identifying the Teeth (continued) • Primary or deciduous teeth • First set of teeth, called “baby” teeth • 20 teeth • Naming of teeth by quadrant (maxillary and mandibular) • Refer to Figure 19-3 in Text

12. 19:2 Identifying the Teeth (continued) • Permanent or succedaneous teeth • Second or permanent set of teeth • 32 teeth • 16 maxillary and 16 mandibular

13. 19:3 Identifying Teeth Using the Universal/National Numbering System and the Federation Dentaire International (FDI) System • Universal/National Numbering System • Primary teeth identified using letters from A to T • Permanent teeth identified by numbers 1 to 32 • Refer to Figure 19-4 in Text

14. 19:3 Identifying Teeth Using the Universal/National Numbering System and the Federation Dentaire International (FDI) System (continued) • Federation Dentaire International (FDI) System • Two-digit code to identify the quadrant and the tooth • Mouth is divided into four quadrants • Refer to Figure 19-5 in Text

15. 19:4 Identifying the Surfaces of the Teeth • Anterior (toward the front) teeth • Incisors and cuspids • Posterior (toward the back) teeth • Bicuspids and molars • Refer to Figure 19-6 in Text

16. 19:4 Identifying the Surfaces of the Teeth (continued) • Crown surfaces of anterior teeth • Labial —Mesial • Lingual —Distal • Incisal • Refer to Figure 19-7 in Text

17. 19:4 Identifying the Surfaces of the Teeth (continued) • Crown surfaces of posterior teeth • Buccal —Mesial • Lingual —Distal • Occlusal • Refer to Figure 19-8 in Text • Abbreviations for crown surfaces vary by doctor

18. 19:4 Identifying the Surfaces of the Teeth (continued) • Line angles • Form where two crown surfaces meet • Point angles • Form where three crown surfaces meet

19. 19:4 Identifying the Surfaces of the Teeth (continued) • Anterior tooth has eight line angles and four point angles • Suggested abbreviations • Posterior tooth has eight line angles and four point angles • Suggested abbreviations

20. 19:5 Charting Conditions of the Teeth • Conditions of teeth are often charted on dental charts or insurance forms • Forms, symbols used, abbreviations, and other factors vary by dental office • Dental charts are legal records

21. 19:5 Charting Conditions of the Teeth (continued) • Dental charts include • Personal patient information • Medical history • Charting area • Treatment section • Radiographic history • Remarks

22. 19:5 Charting Conditions of the Teeth (continued) • Notation methods for dental charting vary • In most offices, colored pencils are used • Symbols for anatomic diagrams can also vary • All treatments or services are also recorded • Use of computerized dental charting

23. 19:6 Operating and Maintaining Dental Equipment • Follow manufacturer’s recommendations for operation of equipment • Infection control is essential • Follow standard precautions before, during, and after procedures • Refer to Procedure 19:6 in Text

24. 19:6 Operating and Maintaining Dental Equipment (continued) • Occupational Safety and Health Administration (OSHA) requirements • Use personal protective equipment (PPE) • Protective barriers for dental equipment

25. 19:6 Operating and Maintaining Dental Equipment (continued) • Equipment includes • Dental lights • Dental chair • Air compressor • Oral-evacuation system • Assistant’s cart • Tri-flow or air–water syringe • Saliva ejector • High-velocity oral evacuator (HVE) • Cuspidor

26. 19:6 Operating and Maintaining Dental Equipment (continued) • Equipment includes (continued) • Doctor’s cart • Rheostats • Low-speed handpiece • Contra angle for cutting and polishing • Prophylaxis angle for holding cups, etc. • High-speed handpiece (ultraspeed)

27. 19:7 Identifying Dental Instruments and Preparing Dental Trays • Methods for setting up dental trays vary • Organization of trays in proper sequence • Main parts of a dental hand instrument • Blade, nib, or point • Shank • Shaft

28. 19:7 Identifying Dental Instruments and Preparing Dental Trays (continued) • Standard instruments • Mouth mirror • Explorer • Cotton pliers • Scalers • Periodontal probes • Excavator • Chisels

29. 19:7 Identifying Dental Instruments and Preparing Dental Trays (continued) • Standard instruments (continued) • Amalgam instruments • Burnisher • Plastic composite instruments • Surgical instruments • Cleoid-discoid carver • Plastic filling instrument (PFI)

30. 19:7 Identifying Dental Instruments and Preparing Dental Trays (continued) • Examples of tray setups • Prophylactic, or general exam • Amalgam restoration • Composite, or esthetic • Surgical extraction • Refer to Procedure 19:7 in Text

31. 19:8 Positioning a Patient in the Dental Chair • Correct positioning increases efficiency • Supine position in four-handed dentistry • Explain all chair movements • Protective drape and safety glasses on patient • Position light 30–50 inches from mouth • Principles of seating patient in dental chair

32. 19:9 Demonstrating Brushing and Flossing Techniques • Correct brushing and flossing techniques are essential in preventing dental disease • Prevention of carious lesions • Removal of plaque • Prevention of halitosis

33. 19:9 Demonstrating Brushing and Flossing Techniques (continued) • Bass method of brushing • Five surfaces on each tooth • Chewing or biting surface • Facial surface • Lingual surface • Side, or interproximal, surfaces (two per tooth)

34. 19:9 Demonstrating Brushing and Flossing Techniques (continued) • Toothbrushes vary in size, shape, and texture • Toothpastes or dentifrices • Clean teeth, freshen breath • Fluoride to prevent decay • Dental floss • Removes plaque and bacteria

35. 19:10 Taking Impressions and Pouring Models • Impression • Negative reproduction of a tooth, several teeth, or a dental arch • Taken to form a model of an area for restoration treatment that will take place outside of the mouth • Common materials used to take impressions

36. 19:10 Taking Impressions and Pouring Models (continued) • Model • Also called a cast • Positive reproduction of the arches or teeth created from the negative impression • Common materials are plaster or stone

37. Alginate • Irreversible hydrocolloid impression material, cannot be returned from gel to original state • Advantages • Simple, economical, easily removed from tissues • Disadvantages • Not good for fine detail, shrinks, tears/breaks easily when wet

38. Alginate (continued) • Alginate powder • Follow manufacturer’s recommended directions • Storage of alginate material • Cool, dry location • Avoid moisture contamination • Premixed alginate with dispensing unit • Refer to Procedure 19:10A

39. Rubber Base (Polysulfide) • Elastomeric impression material that is elastic and rubbery in nature • Two tubes of paste mixed manually • Base and catalyst • Three types are produced • Can be used for any type of dental impression

40. Rubber Base (Polysulfide) (continued) • Not as subject to size changes as alginate • Models should be poured promptly if possible • Disadvantages • Sulfur-like odor, taste, long setting time, causes permanent stains • Refer to Procedure 19:10B in Text

41. Silicones • Polysiloxane or polyvinylsiloxane • Available in light, medium, and heavy versions • Supplied in two tubes • Base and catalyst

42. Silicones (continued) • Advantages • Not affected by fluids in oral cavity • Impression retains shape and size for a long time • Disadvantages • Latex gloves may inhibit setting • More expensive than rubber-base or polysulfide materials

43. Gypsum Materials • Two main products used to form models • Plaster, stone • Principles for use of gypsum • Refer to Procedures 19:10C and 19:10D in Text • Follow CDC guidelines for infection control when taking impressions and pouring models

44. 19:11 Making Custom Trays • Impression trays that are made to fit a particular patient’s mouth • Model of the patient’s mouth • Impression taken • Stone or plaster model as base for custom tray • Refer to Procedure 19:11 in Text

45. 19:11 Making Custom Trays (continued) • Materials used to produce trays • Acrylic resins are most popular and are self-curing or light-curing • Custom trays are for exclusive use with one patient • Clean and replace all equipment

46. 19:12 Maintaining and Loading an Anesthetic Aspirating Syringe • Anesthesia is used to control pain/discomfort • Types of anesthesia • General anesthesia • Analgesia or sedation • Local anesthesia • Topical anesthesia

47. 19:12 Maintaining and Loading an Anesthetic Aspirating Syringe (continued) • Refer to Procedures 19:12A and 19:12B in Text • Two main kinds of injections for used for local anesthesia • Block • Infiltration or field

48. 19:12 Maintaining and Loading an Anesthetic Aspirating Syringe (continued) • Types of medications used for local anesthesia • Anesthetic carpules (cartridges) • Aspirating syringes • Computer-controlled local anesthetic delivery systems • Use standard precautions

49. 19:13 Mixing Dental Cements and Bases • Cements and bases used in variety of dental procedures • Liner • Base • Cement • Temporary

50. 19:13 Mixing Dental Cements and Bases (continued) • Products include • Varnish • Zinc oxide eugenol (ZOE) • Calcium hydroxide • Zinc phosphate • Polycarboxylate • Some require light curing