ANDREW'S 6 ELEMENTS OF OROFACIAL HARMONY PREPARED BY MBOWA.pptx

this slide is for orthodontic about andrew six key and elements in orthodontic treatment

1. ANDREW’S SIX ELEMENTS OF OROFACIAL HARMONY PRESENTER: MBOWA ERISMUS REG NO: 20/U/19608/PS BDS IV

2. OUTLINE INTRODUCTION DEFINITIONS THE SIX ELEMENTS CONCLUSION REFERENCES

3. INTRODUCTION During 1980’s Andrews began examining photos of models, actors and other people in the magazines. He felt that society being the ultimate judge of beauty, some common characteristics may exist among photos that could aid in orthodontic and surgical diagnosis an treatment planning. He indeed find certain commonalities in the group of photos and from this he began the 6 elements philosophy

4. THE SIX ELEMENTS Arch shape and length Anterior-posterior jaw positions Buccolingual jaw width Vertical jaw measurement Pognion prominence Occlusion

5. ELEMENT I: ARCH SHAPE AND LENGTH The goals of element one include; The roots of both mandible and maxilla to be centered over the basal bone Depth of the core line should be between 0 and 2.5mm The FA points should approximate the WALA ridge with in a range of 1-2.2mm

6. Arch shape and length Element one is achieved using casts, photos and radiographs. Calculate the core discrepancy by comparing the mesiodistal diameters of the corrected arch’s core line to the mesiodistal diameters of all the teeth in the arch. If all the teeth are in element one position, this gives you the arch’s total core line discrepancy

7. Arch shape and length

8. ELEMENT II: AP JAW POSITIONS We use clinical and radiographic data to determine element II position of the jaws The maxilla is in element II position when the maxillary incisors are in element I with the FA points touching the goal anterior limit line(GOAL) The mandible is in element II if it is in key I occlusion with element II maxilla.

9. AP jaw positions To find the GALL the forehead is used First classify the forehead as round, straight or angular to aid in determination of the forehead’s FA point(FFA). Which is the midpoint of clinical forehead,

10. AP jaw relations

11. AP jaw positions Determine the FALL/DALL estimation, which is the distance between the FALL and the DALL. If the DALL is behind the fall we take a negative value and if its in front a positive value is assumed. The patients clinical forehead inclination is used to determine the GALL For every degree the forehead is canted more than 7 degrees, the GALL passes through a point on the forehead that is 0.6mm anterior to the FFA point but never beyond the glabella

12. Nomenclature for expressing jaw position to the GALL Jaws with element I incisors on the GALL are said to be green(G) Jaws with element I incisors behind the GALL are said to be black(B Jaws with element I incisors anterior to the GALL are called red(B A mm measurement of the incisors FA point to the GALL can be added e.g. Maxilla with element I incisor’s FA point 2mm posterior to the GALL is called a B4 maxilla.

13. Use of element II in diagnosis and treatment planning Using acetate tracing the maxilla with element I incisors are positioned with the incisors FA points on the GALL The traced mandible with element I incisors is then placed in kay I relationship. This places the maxilla and mandible in element II positions If and anterior or posterior position is made to place the jaws in element II the same movement would be made surgically The movement of the acetate paper template represent the surgical movement needed to place the jaws in element II position

14. AP jaw positions

15. AP jaw positions

16. ELEMENT III: BUCCOLINGUAL JAW RELATIONSHIPS The mandibular basal bone is naturally element III and it will be unchanged throughout the treatment. The maxilla is element III when the maxillary and mandibular arches are element I and the teeth are in a cusp fossa relationship buccolingually,

17. Buccolingual jaw relationship

18. ELEMENT IV: SUPERIOR INFERIOR JAW RELATIONSHIP Element IV has been divided into four parts with specific objectives for the anterior and posterior parts of the maxilla and mandible. The anterior maxilla is element IV when the FA points of element I maxillary incisors is at the same level as the inferior boarder of the upper lip in repose. Anterior mandible is element IV when the distance measured from the FA point of element I mandibular incisors to the hard tissue menton is approximately half the distance from the condylion to hard tissue gonion

19. Superior inferior jaw relationship For posterior maxilla and mandible to be element IV, the distances between; Glabella to subnasale Subnasale to menton The external auditory meatus to soft tissue gonion. Should all be approximately equal and there should be no posterior open bite when the maxilla and mandible are element IV and in occlusion.

20. Superior inferior jaw relationship

21. ELEMENT V: POGONION PROMINANCE The prominence of the hard tissue pogonion should be unique for each individual. We use the Will’s plane to determine element V Will’s plane is a line perpendicular t o the occlusal plane passing through the FA point of the mandibular element I incisor. Anteroposterior position of will’s plane should match the anteroposterior prominence of hard tissue pogonion.

22. Pogonion prominence The patient has B3 pogonion if its AP position is 3mm posterior to will’s plane The patient has R3 pogonion if its AP position is 3mm anterior to the will’s plane

23. ELEMENT VI: OCCLUSION Andrews research started in 1960 with collection of 120 non orthodontic normal models Models were collected with the help of local dentists, orthodontists and major universities. Then the models were intensively studied to find the characteristics that were consistent with all the normal models.

24. Occlusion Normal occlusion Abnormal occlusion

25. Occlusion After the study of all the 120 models certain characteristics emerged to be consistently present in almost all the models. The ones that proved to be present but inconsistent were dropped. There were 6 that seemed to be present in almost all the normal models and those were named the 6 keys to a normal occlusion on which he based to develop the straight wire appliance.

26. Criteria for selection of the models Had never had orthodontic treatment Were straight and pleasing in appearance Had a bite which looked generally correct From Andrews judgement they would not benefit from orthodontic treatment

27. THE SIX KEYS Molar relationship Crown angulation, the mesiodistal (tip) Crown inclination, labiolingual or buccolingual inclination. Rotations. Spaces Occlusal plane

28. KEY I: MOLAR RELATIONSHIP The distal surface of the distobuccal cusp of the upper first permanent molar occluded with the mesial surface of the mesiobuccal cusp of the lower second permanent molar. Angle’s class 1 molar relationship was observed in all the normal models but that alone left the situation unreceptive to a normal occlusion.

29. Molar relationship

30. KEY II: CROWN ANGULATION(TIP) All the gingival portions of the long axis of teeth in models with normal occlusion were more distal than the incisal portions. The angulations are measured in degrees awarding a plus or minus reading. A plus is awarded when the gingival portion of the long axis of the crown is distal to the incisal portion. A minus is awarded when the gingival portion of the long axis of the crown is mesial to the incisal portion.

31. Crown angulation

32. KEY III: CROWN INCLINATION (LABIOLINGUAL OR BUCCOLINGUAL INCLINATION) The crown inclination is expressed in plus or minus degrees. A plus reading is given if the gingival portion of the crown is lingual to the incisal portion. A minus reading is given when the gingival portion of the crown is labial to the incisal portion. A plus crown inclination existed in the anterior teeth, a minus value would create spaces between the anterior and posterior teeth even though there was sufficient space and the posterior teeth are properly inclined

33. Crown inclination

34. Crown inclination A minus crown inclination existed in each crown from the canine through the upper second premolar. A slightly more negative inclination existed in the first and second upper permanent molars. A progressively greater minus crown inclination existed from the lower canines through the lower second molars.

35. Crown inclination

36. KEY IV: ROTATIONS Teeth should be free of undesirable rotations. If teeth are rotated they often occupy more space they normally would if non rotated. Rotations create unreceptive situations to a normal occlusion.

37. Rotations

38. KEY V : TIGHT CONTACTS Contacts of nonortodontic normal occlusions were tight. If any spaces are available they would hinder presence of a normal occlusion. Serious tooth-size discrepancies should be corrected with crowns so the orthodontist will not have to close the spaces at the expense of a normal occlusion

39. Tight contacts

40. KEY VI: OCCLUSAL PLANE The planes of occlusion found on the nonorthodontic normal models ranged from flat to a slight curve of spee. Intercuspation of teeth is best when the plane of occlusion is relatively flat. A deep curve of spee results in a more contained area for the upper teeth, making normal occlusion impossible. A reverse curve of spee is an extreme form of overtreatment, allowing excessive space for each tooth to be intercuspally placed.

41. Plane of occlusion

42. CONCLUSION The six elements are compatible with health function and appearance. The differences in size age gender shape and ethnicity between individuals have little influence upon optimal positions and relationships of the teeth, arches, jaws and chin when measured relative to the six elements

43. REFERENCES The 6 keys to normal occlusion, Lawrence F. Andrews AP relationship of the maxillary central incisors to the forehead in the adult white males, 2011, Maggie S. A dams, west Virginia university. Google photos.