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What condition is associated with decreased cranial base measurements?
Which of the following nutritional deficiencies can impact the growing dentition?
What is a common feature of cleidocranial dysostosis/dysplasia?
Which infectious disease is linked with dental hypoplasia?
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What postnatal trauma can lead to the early loss of deciduous teeth?
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Which vitamin deficiency is associated with retarded eruption of teeth?
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What genetic condition is associated with a wide nasal bridge and abnormal shoulder development?
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What prenatal factor is known to cause intrauterine molding?
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What is the effect of prolonged force, regardless of its magnitude, on alveolar bone?
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What is the primary result of the remodeling process induced by orthodontic treatment?
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According to the bioelectric theory, what initiates changes in bone metabolism?
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What cellular activity occurs on the concave side of the periosteum during bone remodeling?
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What triggers tooth movement according to the described theories?
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What phenomenon describes the generation of electric signals in crystalline materials under pressure?
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Why is the force applied during orthodontic treatment considered effective despite its brief duration?
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What biological reaction does compressing the periodontal ligament (PDL) primarily lead to?
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What is a common effect of prolonged thumb sucking?
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What condition can result from the presence of macrodontia?
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Which of the following teeth anomalies is characterized by a peg-shaped structure?
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Which factor is most likely to cause posterior crossbite?
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What is one of the consequences of premature loss of deciduous teeth?
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What impact does a low labial frenum have in dental development?
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What is the primary cause of delayed eruption of permanent teeth?
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Which condition refers to the abnormality of tooth shape resembling a cow's molar?
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What happens when there are extra teeth present in the dental arch?
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What oral habit shares similar consequences with thumb sucking regarding dental alignment?
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What complication can occur as a result of retained deciduous teeth?
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Which of the following is a primary outcome of lip biting?
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What is the impact of mouth breathing on dental health?
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What characterizes lingual inclination of mandibular incisors?
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What is a potential cause of abnormal eruptive path in teeth?
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Which condition is considered a local factor in the etiology of malocclusion?
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What sequence of events can improper dental restoration lead to?
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In orthodontic tooth movement, where does bone resorption occur?
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What is defined as a physiologic tooth movement?
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What is a characteristic of orthodontic forces?
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What can the presence of impacted molars indicate?
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Which of these is a potential result of a supernumerary tooth?
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What happens to blood flow when pressure is applied to a tooth during orthodontic treatment?
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Which type of cell is primarily associated with the tension side during orthodontic tooth movement?
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What is the main consequence of maintaining a force on a tooth in terms of osteoclast activity?
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Which factor is NOT influenced by the application of orthodontic force?
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What does the RANKL, RANK, and OPG signaling pathway primarily regulate?
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Which mediator is known to stabilize RANKL expression in the periodontal ligament (PDL) under hypoxic conditions?
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What is the role of prostaglandin E2 (PGE2) in orthodontic tooth movement?
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During orthodontic treatment, what happens to oxygen levels on the tension side?
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Which of the following is a result of hypoxia in the periodontal ligament during orthodontic force application?
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What is the immediate outcome of pressure applied to a tooth in terms of osteoclast and osteoblast activity?
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Which hypothesis was proposed by Schwarz in 1932 regarding orthodontic tooth movement?
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What is a critical event that occurs after orthodontic forces are applied?
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What occurs to the levels of carbon dioxide when tensile force is applied?
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What is the result of tissue compression on the tooth?
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Study Notes
Etiology of Malocclusion: Local & General Factors
- Hypopituitarism: Associated with absent zygomatic prominence, Class III malocclusion, high palatal vault, crowding, and anterior & posterior crossbite. Decreased cranial base measurements and delayed tooth eruption are also observed.
- Cleidocranial Dysostosis/Dysplasia: Birth defect affecting bones and teeth. Characterized by prominent brow and lower jaw, wide nasal bridge, and missing or abnormally developed shoulder and collarbones. Deciduous teeth exfoliate irregularly.
- Infectious Diseases: Mumps can cause dental hypoplasia, while Rubella may lead to delayed tooth eruption.
- Nutritional Deficiencies: Impact growing dentition. Vitamin A and D deficiencies, vitamin B12 deficiency, folic acid deficiency, and protein deficiency can all affect tooth development and eruption. Hypervitaminosis A can cause cleft lip and palate.
- Prenatal Trauma: Intrauterine molding and birth trauma to the mandible are common causes.
- Postnatal Trauma: Includes thumb/finger sucking, lip biting, and nail biting.
- Thumb/Finger Sucking: Normal subclinical up to 3 years old; clinically significant between 3-7 years old; intractable habit beyond 7 years old. Causes include inadequate nursing, insecurity, hunger, or learned habit. Prolonged sucking leads to increased overjet, anterior open bite, maxillary incisor flaring, mandibular incisor lingual inclination, narrow arch, high palatal vault, incompetent lips, posterior crossbite, mandibular retrognathism, maxillary prognathism, and speech defects.
- Lip Biting and Sucking: Causes lower lip lingual inclination, maxillary incisor proclination, and open bite.
- Nail Biting: Similar effects to thumb sucking, including narrow maxillary arches, crowding, incisal edge attrition, and speech defects.
- Mouth Breathing: May be treated with appliances or lip taping.
- Abnormal Tooth Number: Supernumerary teeth cause crowding, rotation, delayed eruption, diastema, and torsiversion. Missing teeth create diastema.
- Anomalies in Tooth Size: Macrodontia causes crowding, while microdontia causes spacing or diastema.
- Anomalies in Tooth Shape: Peg laterals, taurodontism, Hutchinson's teeth, and talon's cusps are examples. Talon's cusp results from enamel and dentin invagination, often in maxillary incisors, and can be unilateral or bilateral. Fusion and gemination can also occur. Dens en dente (dens invaginatus) is an invagination prone to caries and infection.
- Abnormal Labial Frenum: A low frenum can cause diastema and may be treated with frenectomy.
- Premature Loss of Deciduous Teeth: Leads to impacted or misaligned permanent teeth, midline shift, and potential speech defects.
- Prolonged Retention of Deciduous Teeth: Similar issues to premature loss including impacted and misaligned permanent teeth, labial/buccal or palatal/lingual eruption of succedaneous teeth.
- Delayed Eruption of Permanent Teeth: Caused by early loss of adjacent primary teeth, mucosal thickening, heredity, or presence of supernumerary teeth, cysts, or ankylosed deciduous teeth.
- Abnormal Eruptive Path: Secondary to arch length deficiency, supernumerary teeth, retained deciduous teeth, root fragments, traumatic displacement of tooth buds, impacted molars, or coronary cysts.
- Improper Dental Restoration: Teeth drift, leading to occlusal collapse and decreased arch length. Overcontoured restorations decrease space, and undercontoured restorations cause supraeruption.
Biologic & Mechanical Basis of Orthodontic Tooth Movement
- Physiologic Tooth Movement: Naturally occurring, such as eruption, migration, supraeruption, or mesial drifting. Driven by mastication and internal forces.
- Orthodontic Tooth Movement (OTM): Movement due to externally applied force. A PDL phenomenon; the tooth itself doesn't change, only its position.
- Orthodontic Force: Force applied to effect tooth movement, generally lower than orthopedic forces.
- Theories of Tooth Movement: Prolonged force (even low magnitude) triggers a physiologic response leading to bone remodeling and OTM.
- Bone Remodeling: Bone resorption occurs under pressure; bone formation occurs under tension.
- Bioelectric Theory: Changes in bone metabolism are controlled by electric signals produced when alveolar bone flexes under light pressure. Piezoelectric signals initiate remodeling.
- Piezoelectricity: Deformation of crystal structures produces electrical current, altering bone metabolism.
- Pressure-Tension Theory: Stretching or tension on one side and pressure on the opposite side of the tooth when force is applied, causes differing responses in bone remodeling.
- Changes in Oxygen Tension and Release of Chemical Mediators: Oxygen reduction after force application stabilizes RANKL expression, and stimulates cell proliferation & angiogenesis via HIF-1 and VEGF. Hypoxia is critical for remodeling.
- Cell Mediators: Prostaglandin and interleukin-1 beta increase in the PDL after force application, mediating cellular response.
- RANK/RANKL/OPG Signaling Pathway: RANKL (receptor activator of nuclear factor kappa beta ligand) expressed by osteoblasts, binds to RANK on osteoclasts, stimulating osteoclast formation and resorption. OPG (osteoprotegerin) is decoy receptor and inhibitor of RANKL, expressed by osteoblasts.
- Changes in Blood Flow: Related to the magnitude of applied force; sufficient blood flow is necessary for successful OTM. Forces which compromise blood supply hinder OTM.
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Description
This quiz explores the various local and general factors influencing malocclusion, including hypopituitarism, cleidocranial dysostosis, infectious diseases, and nutritional deficiencies. Understand how these factors contribute to dental developmental issues such as irregular exfoliation and delayed eruption. Test your knowledge on the complex interactions between genetics, nutrition, and dental health.
