Etiology-Based Dental and Craniofacial Diagnostics

Inger Kjær is Professor Emerita at the University of Copenhagen, Denmark. A specialist in orthodontics, Inger has two doctoral theses; one in odontology and one in medicine. She has held university positions for 29 years and chief clinical positions in orthodontics and pediatric dentistry outside the university for 11 years. These positions have formed the basis for 214 international scientific articles and a worldwide teaching experience for pre- and postgraduate professionals. Inger is co-author of The Prenatal Human Cranium: Normal and Pathological Development (Wiley-Blackwell, 1999).

Preface, ix

Introduction, xi

Limited access to human material, xi

Content and structure of the book, xi

Acknowledgments, xii

1 Craniofacial development and the body axis: normal and pathological aspects from early prenatal to postnatal life, 1

Body axis pre- and postnatally, 1

Germ disk and notochord, 1

Formation of the vertebral column, 1

Cervical spine pre- and postnatally, 1

The interrelationship between the body axis and the cranium, 2

Craniofacial development pre- and postnatally, 4

Cranial base (excluding the sella turcica), 4

Sella turcica, 7

Maxilla, 8

Mandible, 12

Theca cranii, 15

Vomeral bone, 16

Nasal bones, 17

Temporal bone, 18

Craniofacial morphology and growth, 19

Highlights and clinical relevance, 19

Further reading, 19

2 Craniofacial development and the brain: normal and pathological aspects from early prenatal to postnatal life, 21

Central nervous system in relation to neurocranial development pre- and postnatally, 21

Brain, 21

Spinal cord, 24

Trigeminal ganglia, 26

Vomeronasal organs, 26

Pituitary gland and sella turcica, 28

Peripheral nervous system pre- and postnatally, 32

Jaw innervation and bone formation, 32

Highlights and clinical relevance, 34

Further reading, 35

3 Developmental fields in the cranium and alveolar process, 37

Definition of developmental field, 37

Developmental fields in the cranium, 37

The midaxial cranium, 37

The paraaxial cranium, 37

Frontonasal field, 37

Maxillary field and palatine field, 38

Mandibular field, 40

Theca field, 41

Occipital field, 41

How can craniofacial fields be proven?, 42

Frontonasal field, 42

Maxillary and palatine field, 42

Mandibular field, 43

Theca field, 43

Occipital field, 43

Developmental fields in the alveolar process, 44

The upper jaw and the dentition, 44

The lower jaw and the dentition, 44

Highlights and clinical relevance, 45

Further reading, 45

4 Tooth development and tooth maturation from early prenatal to postnatal life, 46

Histological evaluation of early tooth development, 46

Tissues involved in dental bud formation, 46

Inner enamel epithelium and hard tissue formation, 46

Outer enamel epithelium and crown follicle, 46

Root membrane and root development, 48

Sequences in prenatal tooth formation, 49

Radiographic evaluation of normal dental maturation, 49

Radiographic appearance of prenatal crowns before GA 22 weeks, 50

Radiographic appearance of postnatal dental maturation, 50

Clinical evaluation of dental maturity, 52

Bilateral agreement in tooth maturation, 52

Tooth formation from the initial stages to the eruption stages: relation to fields, gender, age, and skeletal maturity, 52

Similarities and differences in primary and permanent dental development, 53

Highlights and clinical relevance, 53

Further reading, 55

5 Periodontal membrane and peri-root sheet, 56

Periodontal membrane, 56

Peri-root sheet, 56

Definition, 56

Composition and function, 56

The peri-root sheet in the primary and permanent dentition, 56

Highlights and clinical relevance, 58

Further reading, 60

6 Normal tooth eruption and alveolar bone formation, 61

Tooth eruption mechanism and alveolar bone formation, 61

Preemergence phase, 61

Tooth eruption and jaw growth, 66

Jaw size and space, 66

Eruption sequences in the primary and permanent dentition, 68

Bilaterality, 70

Early and late eruption, 70

Highlights and clinical relevance, 71

Further reading, 72

7 Etiology-based diagnostics: methods and classification of abnormal development, 73

Why use etiology-based diagnostics?, 73

Definitions of key words, 73

Etiology, 73

Other key words, 76

Analyzing the dentition, oral cavity, and cranium: practical guide, 77

Anamnestic record, 77

Diagrams for diagnostics, 80

Highlights and clinical relevance, 80

Further reading, 80

8 Deviation in tooth morphology and color: normal and pathological variations including syndromes, 81

Primary dentition: crown, root, and pulp, 81

Malformation of incisors, canines, and molars, 81

Disruption in the primary dentition, 81

Dysplasia in the primary dentition, 87

Permanent dentition: crown, root, and pulp, 88

Malformation of incisors, canines, premolars, and molars, 88

Disruption in the permanent dentition, 98

Dysplasia in the permanent dentition, 106

Abnormal dental development: fields and bilateralism, 107

How to analyze the etiology behind deviation in tooth morphology: is it malformation, disruption or dysplasia?, 109

Highlights and clinical relevance, 109

Further reading, 110

9 Deviations in tooth number: normal and pathological variations including syndromes, 111

Agenesis: possible etiologies, 111

Agenesis of the primary and permanent dentition: hypodontia, 111

Primary dentition agenesis, 111

Permanent dentition agenesis, 112

Syndromes, disruption, dysplasia, and hypodontia, 114

Supernumerary teeth: possible etiologies, 118

Supernumerary teeth in the primary and permanent dentition: hyperdontia, 118

Primary dentition supernumeraries, 118

Permanent dentition supernumeraries, 118

Syndromes, dysplasia, and supernumerary teeth, 120

How to analyze the etiology behind deviation in tooth number, 120

Highlights and clinical relevance, 123

Further reading, 124

10 Tooth eruption and alveolar bone formation: abnormal patterns including syndromes, 125

Pathological eruption of primary teeth, 125

Abnormal times for eruption, 125

Total failure to erupt, 125

Arrested eruption of single teeth, 125

Pathological eruption of permanent teeth, 125

Abnormal times for eruption, 125

Ectopic eruption of maxillary canines, 126

Ectopic eruption of mandibular canines, 127

Transposition, 129

Ectopic eruption of molars, premolars, and other teeth, 129

Arrested eruption after trauma, 129

Arrested eruption due to lack of space, 131

Arrested eruption due to obstacles in the eruption pathway, 131

Primary retention of molars, premolars, and incisors, 132

Secondary retention of molars, premolars, and incisors, 134

Primary failure of tooth eruption, 136

Retention of teeth due to virus attack, 136

Retention due to nonshedding of primary teeth, 137

Abnormal eruption in syndromes and dysplasia, 137

Amelogenesis imperfecta, 137

Ectodermal dysplasia, 139

Linear scleroderma en coup de sabre, 139

Segmental odontomaxillary/mandibular dysplasia, 139

Eruption and heredity, 139

Eruption problems in both dentitions, 142

Localized abnormal alveolar bone formation, 143

Juvenile periodontitis: theory and heredity, 143

Hypophosphatasia and Papillon–Lefèvre, 143

Why analyze the etiology behind abnormal eruption?, 145

Highlights and clinical relevance, 147

Further reading, 147

11 Root and crown resorption: normal and abnormal pattern including syndromes, 149

Tooth resorption theory, 149

Ectodermal tissue, 149

Mesodermal or ectomesenchymal tissue, 150

Neuroectodermal tissue, 150

Resorption in the primary dentition, 151

Pattern of resorption, 151

Shedding times, 152

Resorption in the permanent dentition, 156

When does resorption occur in normally developed individuals?, 156

Dentitions especially susceptible to root resorption, 156

Root resorption and heredity: short roots or resorbed roots?, 158

Root resorption in syndromes, dysplasia, and disruptions, 160

Prevention of root resorption in the permanent dentition, 160

Other examples of resorption, 162

Postemergence resorption, 162

Collum resorption, 162

Aggressive resorption, 162

Preemergence resorption, 162

Crown resorption before emergence, 162

Conclusion, 163

How to analyze the etiology behind abnormal root resorption in the permanent dentition, 164

Highlights and clinical relevance, 166

Further reading, 166

12 Apparently normal nonsyndromic dentitions are phenotypically different: the interrelationship between deviations in the dentition and craniofacial profile, 168

Introduction, 168

Heredity and the dentition, 168

Agenesis and supernumerarity, 168

Morphology, 168

Eruption, 168

Resorption, 168

Dentitions with agenesis of single teeth, 168

Dentitions with multiple tooth agenesis, 170

Dentitions with macrodontic maxillary central incisors, 171

Dentitions with supernumerary teeth, 171

Dentitions with ectopic canines, 172

Buccal ectopia, 172

Palatal ectopia, 172

Dentitions with transpositions, 173

Dentitions with arrested eruption of primary molars, 174

Dentitions suitable for tooth transplantation, 174

Dentitions with arrested eruption of permanent teeth, 174

Primary retention, 174

Secondary retention, 175

Primary failure of tooth eruption, 175

Dentitions with persistence of a primary molar in adulthood, 176

Dentitions with idiopathic collum resorption, 176

Highlights and clinical relevance, 176

Further reading, 176

13 Craniofacial syndromes and malformations: prenatal and postnatal observations, 177

Holoprosencephaly/solitary median maxillary central incisor (SMMCI) syndrome, 177

Prenatal, 177

Postnatal, 177

Cerebellar hypoplasia/cri-du-chat syndrome, 180

Prenatal, 180

Postnatal, 182

Myelomeningoceles/spina bifida and hydrocephalus, 185

Prenatal, 185

Postnatal, 185

Down’s syndrome (trisomy 21), 186

Prenatal, 186

Postnatal, 187

Turner’s syndrome, 187

Prenatal, 187

Postnatal, 187

Fragile X syndrome, 187

Prenatal, 187

Postnatal, 188

Crouzon’s syndrome, 188

Prenatal, 188

Postnatal, 189

DiGeorge’s/velocardiofacial syndrome, 189

Prenatal, 189

Postnatal, 189

Cleft lip and palate, 190

Cleft lip: pre- and postnatal findings, 190

Isolated cleft palate: pre- and postnatal findings, 190

Combined cleft lip and palate: pre- and postnatal findings, 192

Cleft lip and palate etiologies, 193

Comparison between pre- and postnatal findings: results and restrictions, 194

Results, 194

Restrictions, 194

Malformations: nonsyndromic examples, 194

Highlights and clinical relevance, 199

Further reading, 200

14 Craniofacial disruptions: prenatal and postnatal observations, 202

Prenatal disruptions, 202

Amniotic band: sequence, 202

Virus infection and maternal alcohol intake, 202

Postnatal disruptions, 202

Premature birth, 202

Trauma, 202

Virus and bacterial attack, 202

Brain tumors and radiation/chemotherapy, 203

Acromegaly, 203

Highlights and clinical relevance, 204

Further reading, 206

15 Craniofacial dysplasia: prenatal and postnatal observations, 207

Endochondral and intramembranous bone dysplasia in the cranium, 207

Chondrodystrophy, 207

Osteogenesis imperfecta, 207

Osteosclerosis, 207

Hypophosphatemic rickets, 211

Dysostosis cleidocranialis, 211

Dysplasia in nonosseous tissue, 211

Ectodermal dysplasia, 211

Localized scleroderma en coup de sabre, 211

Amelogenesis imperfecta, 212

Dentinogenesis imperfecta and dentin dysplasia, 212

Suture dysplasia, 214

Highlights and clinical relevance, 214

Further reading, 216

16 Hard tissue as a diagnostic tool in medicine, 217

Introduction, 217

Perspectives for prenatal craniofacial pathology, 217

Perspectives for perinatal and pediatric pathology, 218

Perspectives for clinical and basic research, 219

The prenatal cranium as a predictor for postnatal development, 219

The dentition as a diagnostic tool in medicine, 220

Association between dental and craniofacial development, 220

Perspectives for anthropology, 221

Conclusion, 222

Further reading, 223

17 Clinical cases and unanswered questions, 224

Clinical cases, 224

Conditions in diagnostics, treatment planning, and outcome, 224

Optimal treatment situation, 224

Observation of the condition, 224

Nonoptimal treatment situations, 224

Examples of diagnostics and treatment of eruption problems, 225

Problems in permanent molar eruption: later diagnosed as primary retention, 225

Problems in permanent molar eruption: later diagnosed as secondary retention, 225

Problems in permanent molar eruption: later diagnosed as primary failure of eruption, 225

Problems in premolar eruption, 226

Eruption problems can be a sign of susceptibility to root resorption, 230

Eruption problems caused by supernumerary teeth, 230

Unanswered questions, 230

“What is this?”, 230

“Can medication influence tooth formation?”, 232

Further reading, 233

Index, 235