1	Primary Dentition Occlusion Mark H. Taylor, D.D.S., F.A.C.D.
2	Sequence of Calcification of Primary Teeth
3	Sequence of Eruption of Primary Teeth (Lunt and Law) a - b - d - c - e b-c-d earlier in maxilla girls erupt faster than boys 6 month variation = normal no significant left/right differences
4	Sequence of Eruption of Primary Teeth (Lunt and Law)
5	Positioning of Primary Teeth
6	Traumatic Injury to Primary Incisor May cause hypocalcification, hypoplasia, and/or dilaceration of the permanent successor. Due to positional relationship of the permanent and primary incisors.
7	Traumatic Injury to Primary Incisor Focal Hypocalcification
8	Traumatic Injury to Primary Incisor Focal Hypoplasia
9	Traumatic Injury to Primary Incisor Dilaceration
10	The Ideal Primary Occlusion Ovoid arches Good interdental or primary spacing Flush terminal plane or mesial step molars Neutro cuspids
11	The Perfect Primary Occlusion
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15	Occlusion of the Primary Second Molar Look at the distal aspect of the 2nd molar Flush terminal plane – most common Mesial step Disto step Mesio step
16	Flush Terminal Plane
17	Mesial Step
18	Disto Step
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20	Mesio Step
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23	Primary Cuspid Occlusion Look at long axis of the maxillary cuspid Neutro cuspid (Class I) Disto cuspid (Class II) Mesio cuspid (Class III)
24	Neutro Cuspid
25	Neutro Cuspid
26	Disto Cuspid
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29	Mesio Cuspid
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32	Arch Length Prediction from Alignment of Primary Teeth
33	No Primary Spacing
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38	Fair-Good Spacing
39	Good Spacing
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46	No Crossbites
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50	Ankylosis
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52	Development of the Tooth Initiation (Bud Stage) Early as 6th week of embryonic life All primary teeth and permanent molars arise from the dental lamina Permanent incisors, canines, and premolars arise from the primary predecessor Failure of initiation results in congenitally missing teeth Excessive budding results in supernumerary teeth
53	Congenitally Missing
54	Supernumerary Teeth
55	Supernumeraries 060817
56	Supernumeraries 060817
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64	Development of the Tooth Proliferation (Cap Stage) Peripheral cells of the cap form the inner and outer enamel epithelium Failure in proliferation results in congenitally missing teeth Excessive proliferation results in a cyst, odontoma, or supernumerary tooth, depending on amount of cell differentiation
65	Development of the Tooth Histodifferentiation and Morphodifferentiation (Bell Stage) Cells of dental papilla differentiate into odontoblasts Cells of the inner enamel epithelium differentiate into ameloblasts Failure in histodifferentiation results in structural abnormalities of the enamel and dentin (amelogenesis imperfecta, dentinogenesis imperfecta) Failure in morphodifferentiation results in size and shape abnormalities, such as peg lateral incisors and macrodontia.
66	Peg Lateral Incisors
67	Macrodont
68	Fusion Fusion is the union of two primary or permanent teeth. More common in primary teeth. Fused teeth have two pulp chambers and two pulp canals. Almost always in anterior teeth.
69	Fusion
70	Fusion
71	Gemination Gemination is the division of a single tooth bud resulting in a bifid crown. More common in primary teeth. Geminated teeth have a single pulp chamber.
72	Gemination
73	Gemination
74	Development of the Tooth Apposition Ameloblasts and odontoblasts deposit a layerlike matrix Disturbances in apposition result in incomplete tissue formation. For example, an intrusive injury to a primary incisor may disrupt enamel apposition and result in an area of enamel hypoplasia.
75	Development of the Tooth Calcification Enamel is composed of 96% inorganic material and 4% organic material and water Calcification begins at cusp tips and incisal edges and proceeds cervically Localized infection, trauma, and excessive systemic fluoride ingestion may cause hypocalcification.
76	Fluorosis
77	Fluorosis
78	The End