1. Development of teeth and clinical systems of coding teeth Lanzhou university school of stomatology

2. Development of teeth Tooth germs Tooth germs 6th fetal week 6th fetal week Small clumps of cells that develop into teeth Small clumps of cells that develop into teeth Teeth develop & grow in tiny crypts within the alveolar process Teeth develop & grow in tiny crypts within the alveolar process Calcification-hardening of the tooth tissues by the deposition of mineral salts within these tissues Calcification-hardening of the tooth tissues by the deposition of mineral salts within these tissues Process: begins 4th or 5th month of fetal life (primary dentition) until year 3 or 4 years of age Process: begins 4th or 5th month of fetal life (primary dentition) until year 3 or 4 years of age Permanent teeth -begins to calcify after birth - 25yrs Permanent teeth -begins to calcify after birth - 25yrs

3. Development of teeth

4. Developmental Lobes and Cusps Developmental lobes Developmental lobes Anterior teeth 4 major growth centers called lobes Anterior teeth 4 major growth centers called lobes Mamelons Mamelons Cingulum Cingulum Posterior teeth 4 or 5 lobes Posterior teeth 4 or 5 lobes Coalescence of lobes marked by developmental grooves Coalescence of lobes marked by developmental grooves

5. Lobes Molars Molars 4 lobes: 4 lobes: Distolingual, distofacial, mesiolingual, and mesiofacial Distolingual, distofacial, mesiolingual, and mesiofacial Maxillary First Molars Maxillary First Molars 5th cusp Maxillary - Cusp of Carabelli 5th cusp Maxillary - Cusp of Carabelli Mandibular First Molars Mandibular First Molars 5th cusp - Distal cusp 5th cusp - Distal cusp

6. Development, Form, and Eruption Eruption & Calcification Eruption & Calcification Calcification- elements and chemicals present in the body Calcification- elements and chemicals present in the body Body may use replacements resulting in improper form alter tooth formation: Body may use replacements resulting in improper form alter tooth formation: Fever Fever Metabolic dysfunction Metabolic dysfunction Childhood or nutritional disease Childhood or nutritional disease Physical trauma Physical trauma

7. Development, Form, and Eruption Eruption Schedule: Primary Eruption Schedule: Primary Central incisors Central incisors 6 ½ to 8 mos. 6 ½ to 8 mos. Lateral Incisors Lateral Incisors 7 to 9 mos. 7 to 9 mos. First molars First molars 12 to 16 mos. 12 to 16 mos. Canines Canines 16 to 21 mos. 16 to 21 mos. Second molars Second molars 21 to 30 mos. 21 to 30 mos.

8. Development, Form, and Eruption Eruption Schedule: Permanent Eruption Schedule: Permanent Central incisor Central incisor 6 to 8 yrs 6 to 8 yrs Lateral incisor Lateral incisor 7 to 9 yrs 7 to 9 yrs Canine Canine 9 to 12 yrs 9 to 12 yrs First Premolar 10 to 12 yrs Second Premolar 10 to 12 yrs First molar 6 to 7 yrs Second Molar 12 to 13 yrs Third molar 17 to 22 yrs

9. Development, Form, and Eruption Terms Terms Exfoliation - the process by which the roots of a baby tooth are resorbed and dissolved until the deciduous tooth falls out. Exfoliation - the process by which the roots of a baby tooth are resorbed and dissolved until the deciduous tooth falls out. Resorption - Osteoclasts (bone destroying cells) destroys the root of the deciduous tooth. Resorption - Osteoclasts (bone destroying cells) destroys the root of the deciduous tooth. Congenitally missing - a tooth that never forms because a tooth bud was never produced. Congenitally missing - a tooth that never forms because a tooth bud was never produced. Attrition - the wearing away of the tooth through mechanical wear. Attrition - the wearing away of the tooth through mechanical wear. Mixed dentition - Primary and secondary teeth present. Mixed dentition - Primary and secondary teeth present. Edentulous - no teeth Edentulous - no teeth

10. Development, Form, and Eruption General rules General rules Mandibular teeth usually precede maxillary teeth Mandibular teeth usually precede maxillary teeth Erupt in pairs one on right and one on left Erupt in pairs one on right and one on left Perm teeth erupt slightly earlier in girls than in boys Perm teeth erupt slightly earlier in girls than in boys

11. Arrangement of teeth Arrangement of teeth Arrangement of teeth Dentition refers to the arrangement of the teeth as a set. Dentition refers to the arrangement of the teeth as a set. Primary teeth present - primary dentition Primary teeth present - primary dentition 20 20 Secondary teeth present - secondary dentition Secondary teeth present - secondary dentition 32 32 Both present - mixed dentition Both present - mixed dentition The permanent teeth that replace deciduous teeth - Succedaneous The permanent teeth that replace deciduous teeth - Succedaneous Permanent molars are nonsuccedaneous teeth Permanent molars are nonsuccedaneous teeth

12. Clinical systems of coding teeth Naming and Coding of Teeth Naming and Coding of Teeth Each tooth given name and identification code so that dental offices, insurance companies, dentists, and staff can better communicate Each tooth given name and identification code so that dental offices, insurance companies, dentists, and staff can better communicate Four systems: Four systems: Quadrant coding method Quadrant coding method Universal System Universal System Palmer Notation system Palmer Notation system Federation Denature International (FDI) systems Federation Denature International (FDI) systems

13. Clinical systems of coding teeth DENTAL ARCHES DENTAL ARCHES Upper arch Upper arch Maxillary Maxillary Upper arch Upper arch Mandibular Mandibular Each arch divided into right and left quadrant Each arch divided into right and left quadrant Separated by a midline Separated by a midline

14. Clinical systems of coding teeth  Quadrant coding method Coding permanent teeth

15. Coding deciduous teeth with the Roman numerals Coding deciduous teeth with the Roman numerals Clinical systems of coding teeth

16. Universal System Universal System Arabic numbers 1 through 32 for permanent. Arabic numbers 1 through 32 for permanent. #1 is assigned to the most posterior molar on the upper right #1 is assigned to the most posterior molar on the upper right #32 Permanent mandibular third molar #32 Permanent mandibular third molar A through T for the primary teeth. A through T for the primary teeth. Assigned likewise Assigned likewise

17. Clinical systems of coding teeth International dental federation system International dental federation system (FDI System ) 1st number represents quadrant 1st number represents quadrant 2nd number represents tooth position from midline 2nd number represents tooth position from midline Example: FDI 16 is the Maxillary Right 1st molar Example: FDI 16 is the Maxillary Right 1st molar

18. Clinical systems of coding teeth permanent permanent 18 17 16 15 14 13 12 11 21 22 23 24 25 26 27 28 ────────────────────── 18 17 16 15 14 13 12 11 21 22 23 24 25 26 27 28 ────────────────────── 48 47 46 45 44 43 42 41 31 32 33 34 35 36 37 38 48 47 46 45 44 43 42 41 31 32 33 34 35 36 37 38 Decidous Decidous 55 54 53 52 51 61 62 63 64 65 ────────────── 85 84 83 82 81 71 72 73 74 75

19. Clinical systems of coding teeth Palmer Notation System Palmer Notation System Each of the 4 quads is given its own prefix symbol Each of the 4 quads is given its own prefix symbol Lowest number is closest to the midline and highest number (8) is assigned to third molars Lowest number is closest to the midline and highest number (8) is assigned to third molars Coding deciduous teeth use characters A,B,C,D,E Coding deciduous teeth use characters A,B,C,D,E

20. Terms and anatomic landmarks of teeth Applied terms Applied terms median line median line

21. median line

22. Terms and anatomic landmarks of teeth Long axis Long axis Long axis Long axis Contact area Contact area Contact area Contact area Line angle Line angle Line angle Line angle Point angle Point angle Point angle Point angle Height of contour Height of contour Height of contour Height of contour Division into thirds Division into thirds Division into thirds Division into thirds

24. Height of contour An imaginary curved line encircling a tooth at its greatest bulge An imaginary curved line encircling a tooth at its greatest bulge Also afford the correct amount of frictional massage to the gingiva Also afford the correct amount of frictional massage to the gingiva Cleansing mechanism Cleansing mechanism General rule: General rule: Contour will vary from tooth to tooth Contour will vary from tooth to tooth Height of contour for both anterior and posterior teeth is in the cervical third Height of contour for both anterior and posterior teeth is in the cervical third Except lingual crest of curvature of posterior teeth which is near the middle third. Except lingual crest of curvature of posterior teeth which is near the middle third.

25. Height of contour

26. Contact area Location of the Contact areas & embrasures Location of the Contact areas & embrasures Facial view Contact areas Facial view Contact areas Anterior teeth Anterior teeth Contact areas are closer to the incisal third of the teeth Contact areas are closer to the incisal third of the teeth Except Distal of Canine...middle third Except Distal of Canine...middle third Occlusal / Incisal view Contact areas Occlusal / Incisal view Contact areas Anterior teeth Anterior teeth Contact areas in the center from a facial to lingual direction Contact areas in the center from a facial to lingual direction

27. Contact area

28. Contact areas Location of the Contact areas, & embrasures Location of the Contact areas, & embrasures Posterior teeth Posterior teeth Contacts are located more facially Contacts are located more facially Middle to Cervical third Middle to Cervical third Posterior teeth Posterior teeth Slightly buccal to the center Slightly buccal to the center Lingual embrasure usually larger Lingual embrasure usually larger

29. Division into thirds

30. Terms and anatomic landmarks of teeth Names of crown surfaces labial surface and buccal surface labial surface and buccal surface labial surface and buccal surface labial surface and buccal surface lingual surface lingual surface lingual surface lingual surface medial surface medial surface medial surface medial surface distal surface distal surface distal surface distal surface occlusal surface and incisor ridge occlusal surface and incisor ridge occlusal surface and incisor ridge occlusal surface and incisor ridge

31. The labial is the surface of an anterior tooth that faces toward the lips. The buccal is the surface of a posterior tooth that faces toward the cheek. The labial is the surface of an anterior tooth that faces toward the lips. The buccal is the surface of a posterior tooth that faces toward the cheek.

32. The lingual is the sur face of an anterior o r posterior tooth that faces toward the tongue The lingual is the sur face of an anterior o r posterior tooth that faces toward the tongue

33. Terms and anatomic landmarks of teeth

35. Anatomic landmarks of crown surfaces Convex portion of dental crown Convex portion of dental crown Dental cusp Dental cusp Tubercle Tubercle

36. Cingulum Cingulum Ridge Ridge Axial ridge Axial ridge Marginal ridge Marginal ridge Incisor ridge Incisor ridge Triangular ridge Triangular ridge Transverse ridge Transverse ridge Oblique ridge Oblique ridge Cusp ridge Cusp ridge Cervical ridge Cervical ridge

37. Terms and anatomic landmarks of teeth Concave portion of dental crown Fossa Fossa Groove Groove Development groove Development groove Supplement groove Supplement groove Fissure Fissure Pit Pit

38. Terms and anatomic landmarks of teeth Inclined surface Development lobe Development lobe