Development of dentition & occlusion / /certified fixed orthodontic courses by Indian dental academy
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The document outlines the developmental stages of dentition and occlusion, detailing the formation of deciduous and permanent teeth, including their embryonic origins and the various stages of tooth development. It describes the characteristics of each stage, including primary and mixed dentition, and the establishment of normal occlusion, along with the various factors influencing dental spacing and alignment. Additionally, it highlights Andrew’s six keys of occlusion and the relationships of molars that are critical for proper dental function.
Development of dentition & occlusion / /certified fixed orthodontic courses by Indian dental academy
- 1. DEVELOPMENT OF DENTITION & OCCLUSION INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com
- 2. DEVELOPMENT OF TEETH: •The embryonic oral cavity is lined by stratified squamous epithelium- ORAL ECTODERM •Around 6th week of intra uterine life, the infero-lateral border of the maxillary arch & the supero-lateral border of the mandibular arch show localized proliferation of the oral ectoderm resulting in the formation of a HORSE SHOE SHAPED BAND of tissue called DENTAL LAMINA. www.indiandentalacademy.com
- 3. •Deciduous teeth are formed by direct proliferation of the dental lamina. •The permanent teeth that replace the primary teeth develop from its lingual extension while the others develop from its posterior extension called SUCCESSIONAL LAMINA. www.indiandentalacademy.com
- 5. Stages of tooth development •BUD STAGE •CAP STAGE •EARLY BELL STAGE •LATE BELL STAGE •ROOT FORMATION •APICAL CLOSURE & FORMATION OF APICAL FORAMEN www.indiandentalacademy.com
- 6. The ectoderm in certain areas undergo proliferation to form knob like projection that grow into the underlying mesenchyme which form the future ENAMAL ORGAN. Ten such swellings are seen in each arch representing the 20 deciduous teeth www.indiandentalacademy.com
- 7. Development of OCCLUSION STAGES: •GUM PAD STAGE •DECIDIOUS DENTITION STAGE •MIXED DENTATION STAGE FIRST TRANSITIONAL PERIOD INTER TRANSITIONAL PERIOD SECOND TRANSITIONAL PERIOD •PERMANENT DENTATION STAGE www.indiandentalacademy.com
- 8. GUM PAD STAGE •THIS IS THE PERIOD AFTER BIRTH DURING WHICH THE NEONATE DOES NOT HAVE ANY TEETH. •IT USUALLY LASTS FOR 6 MONTHS AFTER BIRTH •THE ALVEOLAR PROCESSES AT THE TIME OF BIRTH ARE KNOWN AS GUM PADS. •THEY ARE PINK, FIRM & ARE COVERED BY A DENSE LAYER OF FIBROUS PERIOSTEUM. www.indiandentalacademy.com
- 9. • THEY ARE HORSE SHOE SHAPED AND DEVELOP INTO 2 PARTS: LABIO BUCCAL PORTION LINGUAL PORTION • THESE ARE SEPERATED FROM EACH OTER BY A GROOVE CALLED DENTAL GROOVE. •THE GUM PADS ARE DIVIDED INTO 10 SEGMENTS BY CERTAIN GROOVES CALLED TRANSVERSE GROOVES.EACH OF THESE CONSISTS OF 1 DEVELOPING DECIDIOUS TOOTH SAC. •THE GINGIVAL GROOVE SEPERATES THE GUM PADS FROM THE PALATE AND THE FLOOR OF THE MOUTH. •THE TRANSVERSE GROOVE BETWEEN THE CANINE & 1ST DECIDIOUS MOLAR SEGMENT IS CALLED THE LATERAL SULCUS. www.indiandentalacademy.com
- 10. •The upper & lower gum pads are almost similar to each other . •The upper gum pad is both wider as well as longer than the mandibular gum pad. •When the upper and lower gum pads are approximated there is a complete over jet all around. •Contact occurs between the upper and lower gum pads in the 1st molar region & a space exists between the anterior region. •This infantile open bite is considered normal & it helps in suckling. www.indiandentalacademy.com
- 11. DECIDIOUS DENTATION STAGE THE PRIMARY DENTATION STAGE EXTENDS FROM ERUPTION OF THE PRIMARY TEETH UNTIL THE ERUPTION OF 1ST PERMANENT TOOTH AROUND 6 YEARS OF AGE. CHARACTERSTICS OF PRIMARY DENTATION: •OVER BITE •SPACING •MOLAR RELATION www.indiandentalacademy.com
- 12. OVER BITE • IT IS THE AMOUNT OF VERTICAL OVER LAP BETWEEN MAXILLARY AND MANDIBULAR CENTRAL INCISORS. • DEEP BITE MAY BE SEEN IN THE INITIAL STAGES OF DEVELOPMENT. • IT IS ASSENTUATED BY THE FACT THAT DECIDIOUS INCISORS ARE MORE UPRIGHT WITH THE LOWER INCISOR EDGES ALMOST CONTACTING THE UPPER CINGULUM. • THIS DEEP BITE REDUCES LATER DUE TO: 1. ERUPTION OF DECIDIOUS MOLARS 2. ATTRITIION OF INCISORS 3. FORWAD GROWTH OF MANDIBLE • In about 24% of the children open bite is noted due to various HABITS. www.indiandentalacademy.com
- 13. SPACING IN A PRIMARY DENTATION STAGE A CHILD MAY HAVE GENERALISED SPACING; NO SPACING; LOCALISED SPACING OR CROWED DENTATION. GENERALISED SPACING OCCURS IN ALMOST 2/3RD OF THE CHILDREN REFERED TO AS PHYSIOLOGICAL SPACES OR DEVELOPMENTAL SPACES LOCALISED SPACES LIKE PRIMATE SPACE ARE ALSO SEEN www.indiandentalacademy.com
- 14. PRIMATE SPACE ALSO CALLED SIMIAN SPACE OR ANTHROPOID SPACE SEEN IN ABOUT 87% CASES IN THE MAXILLARY ARCH IT IS PRESENT BETWEEN LATERAL AND CANINE. IN THE MANDIBULAR ARCH SEEN BETWEEN CANINE AND 1ST DECIDIOUS MOLAR. THIS SPACE IS USED UP BY THE DEVELOPING LARGER PERMANENT TEETH. www.indiandentalacademy.com
- 15. NO SPACE •NO SPACING BETWEEN THE PRIMARY INCISORS GUARANTEES INSUFFICIEN ROOM FOR THE PERMANENT INCISORS TO ERUPT THUS RESULTING IN SEVERE CROWDING REFERED TO AS HOLLYWOOD SMILE. www.indiandentalacademy.com
- 16. Molar Relation • In the primary dentition the molar relation is described in terms of TERMINAL PLANES. • THE TERMINAL PLANES ARE THE DISTAL SURFACES OF THE 2ND PRIMARY MOLARS. THESE TWO TERMINAL PLANES CAN BE RELATED IN 3 WAYS: 1. FLUSH TERMINAL PLANE 2. MESIAL TERMINAL PLANE 3. DISTAL TERMINAL PLANE www.indiandentalacademy.com
- 17. FLUSH TERMINAL PLANE: BOTH MAXILLARY & MANDIBULAR PLANES ARE AT THE SAME LEVEL ANTERIO-POSTERIORLY. MESIAL STEP TERMINAL PLANE: MAXILLARY TERMINAL PLANE IS RELATIVELY MORE POSTERIOR THAN THE MANDIBULAR TERMINAL PLANE FORMING A MESIAL STEP DISTAL STEP TERMINAL PLANE: THE MAXILLARY TERMINAL PLANE IS RELATIVELY MORE ANTERIOR THAN THE MANDIBULAR TERMINAL PLANE. www.indiandentalacademy.com
- 18. ERUPTION SEQUENCE OF PRIMARY TEETH www.indiandentalacademy.com
- 19. MIXED DENTITION PERIOD THIS STAGE STARTS WITH THE ERUPTION OF THE PERMANENT 1ST MOLAR BY THE AGE OF 6 YEARS TO THE COMPLETION OF EXFOLIATION OF ALL DECIDIOUS TEETH AT THE AGE OF 12-13 YEARS. IN THE EARLY PART OF MIXED DENTITION THERE MAY BE A TEMPORARY OPEN BITE USUALLY DUE TO INCOMPLETE ERUPTION OF INCISORS OR A PERSISTENT HABIT. www.indiandentalacademy.com
- 20. PHASES OF MIXED DENTITION FIRST TRANSITION PERIOD: EMERGENCE OF 1ST PERMANENT MOLAR INCISORS TRANSITION ESTABLISHMENT OF OCCLUSION INTER TRANSITION PERIOD BOTH SETS OF TEETH PRESENT 4 PERMANENT INCISORS & 1ST PERMANENT MOLARS PRESENT DECIDIOUS CANINES AND 1ST & 2ND MOLARS SECOND TRANSITION PERIOD EMERGENCE OF BICUSPIDS, CUSPIDS,& SECOND PERMANENT MOLAR. www.indiandentalacademy.com ESTABLISHMENT OF OCCLUSION
- 21. FIRST TRANSITIONAL PERIOD Emergence of 1st permanent molar: ERUPTS BY AROUND 6TH YEAR OF LIFE ITS LOCATION & RELATIONSHIP DEPENDS UPON THE DISTAL SURFACE RELATIONSHIP BETWEEN UPPER AND LOWER SECOND DECIDIOUS MOLARS. THE DISTAL SURFACE OF THESE DECIDIOUS 2ND MOLARS GUIDE THE ERUPTING PERMANENT MOLAR INTO 3 RELATIONS: www.indiandentalacademy.com
- 23. INCISAL LIABILITY •THE UNERUPTED PERMANENT INCISORS ARE LARGER THAN THE DECIDIOUS INCISORS. •THIS IS REFERED TO AS INCISAL LIABILITY. ARCH INCISAL LIABILITY MAXILLA 7 mm MANDIBLE 5 mm www.indiandentalacademy.com
- 24. INCISAL LIABILITY IS OVERCOME BY THE FOLLOWING FACTORS: 1. UTILIZATION OF INTERDENTAL SPACES SEEN IN PRIMARY DENTITION. 2. INCREASE IN INTER-CANINE WIDTH 3. CHANGE IN INCISOR INCLINATION www.indiandentalacademy.com
- 25. INTER-TRANSITIONAL PERIOD THIS IS A LATENT PERIOD WITH NO EXCHANGE OF TEETH TAKING PLACE. PERMANENT INCISORS AND 1ST MOLAR ARE PRESENT. DECIDIOUS CANINE, 1ST & 2ND MOLARS ARE PRESENT BY THE END OF THIS STAGE ALL THE TEETH ARE IN PROPER OCCLUSION. www.indiandentalacademy.com
- 26. SECOND TRANSITION PERIOD CHARACTERISED BY REPLACEMENT OF DECIDIOUS CANINES & MOLARS BY PREMOLARS AND PERMANENT CUSPIDS RESPECTIVELY. ERUPTION OF THE NON SUCCEDENOUS TEETH i.e., 2ND MOLARS. ESTABLISHMENT OF PROPER OCCLUSION www.indiandentalacademy.com
- 27. LEEWAY SPACE OF NANCE THE COMBINED MESIO DISTAL WIDTH OF THE PERMANENT CANINES AND PREMOLARS IS USUALLY LESS THAN THAT OF THE DECIDIOUS CANINES & MOLARS. THIS SURPLUS SPACE IS CALLED AS LEEWAY SPACE OF NANCE. ARCH LEEWAY SPACE MAXILLARY 1.8 mm (0.9 mm in each arch) MANDIBULAR 3.4 mm (1.7 mm in each arch) www.indiandentalacademy.com
- 28. UGLY DUCKLING STAGE AS THE DEVELOPING PERMANENT CANINES ERUPT, THEY DISPLACE THE ROOTS OF THE LATERAL INCISORS MESIALLY AND INTURN ON TO THE CENTRAL INCISORS. THIS CAUSES THE FLARING UP OF THE INCISOR CROWNS. THUS CAUSING A MIDLINE DIASTEMA THIS SITUATION IS BEING DESCRIBED BY BROADBENT AS UGLY DUCKLING STAGE. THIS OCCURS AROUND THE AGE OF 8-9 YEARS THIS CORRECTS BY ITSELF WHEN THE PERMANENT CANINE ERUPTS COMPLETELY. www.indiandentalacademy.com
- 30. PERMANENT DENTITION STAGE ALL THE PERMANENT TEETH ARE FORMED AROUND BIRTH. THIS STAGE BEGINS WITH THE EXFOLIATION OF LAST PRIMARY TEETH AND ERUPTION OF ALL PERMANENT TEETH EXCEPT 3RD MOLAR. THE IMPORTANT CHARACTERSTICS OF NORMAL OCCLUSION IN PERMANENT DENTITION WERE: DESCRIBED BY ANDREW’S IN 1972 AS 6 KEYS OF OCCLUSION. www.indiandentalacademy.com
- 32. ERUPTION SEQUENCE OF PERMANENT TEETH www.indiandentalacademy.com
- 33. ANDREW’S 6 KEYS OF OCCLUSION KEY 1: MOLAR INTER ARCH RELATIONSHIP KEY 2: MESIO DISTAL CROWN ANGULATION KEY 3: LABIO LINGUAL CROWN INCLINATION www.indiandentalacademy.com
- 34. KEY 4: ABSENCE OF ROTATION KEY 5: TIGHT CONTACTS KEY 6: CURVE OF SPEE www.indiandentalacademy.com
- 35. MOLAR RELATIONS • PROPOSED BY E H ANGLE IN 1899 DEPENDING ON 1ST MOLAR RELATIONSHIP FOR PERMANENT DENTITION CLASS 1 CLASS 2 DIV 1 DIV 2 CLASS 3 TRUE PSEUDO www.indiandentalacademy.com
- 36. COMPENSATORY CURVES CURVE OF SPEE: ANTERIO POSTERIOR CURVE PASSING THROUGH THE BUCCAL CUSPS OF PREMOLARS AND MOLARS ON TO THE ANTERIOR BORDER OF RAMUS TO END ON THE CENTER OF CONDYLE. CURVE OF WILSON: IT IS A MEDIO LATERAL CURVE PASSING THROUGH BUCCAL TO PALATAL AND THEN PALATAL TO BACCAL OF THE OTHER SIDE. CURVE OF MONSON: IT IS A COMBINATION OF BOTH MEDIO LATERAL AND ANTERIOPOSTERIOR CURVE TO FORM A 8 INCH SPHERE WITH CENTER ON GLABELLA. www.indiandentalacademy.com
- 37. "Live as if you were to die tomorrow. Learn as if you were to live forever." -Mahatma Gandhi THANK YOU INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com