Malocclusion general factors /certified fixed orthodontic courses by Indian dental academy

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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.


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Malocclusion general factors /certified fixed orthodontic courses by Indian dental academy

  1. 1. Etiology Of Malocclusion – General Factors www.indiandentalacademy.com
  2. 2. INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  3. 3. Introduction Malocclusion may be defined as a significant deviation from what is defined as normal or ideal occlusion (Andrews,1972) *. The term ‘normal occlusion' is arbitrary, but is generally accepted to be class I molar relationship with good alignment of all teeth *. *(The heritability of malocclusion:part 2. P.A. Mossey, British journal of orthodontics/vol. 26/1999) www.indiandentalacademy.com
  4. 4. Classification Graber’s Moyer’s White & Gardiner’s Salzmann’s www.indiandentalacademy.com
  5. 5. Moyer’s        Heredity Developmental defects of unknown origin Trauma Physical agents Habits Diseases Malnutrition www.indiandentalacademy.com
  6. 6. White & Gardiner’s    Dental base abnormalities Pre-eruption abnormalities Post-eruption abnormalities www.indiandentalacademy.com
  7. 7. Salzmann’s GENETIC ENVIRONMENTA L DEVELOPMENT AL CONGENITAL www.indiandentalacademy.com FUNCTIONA L
  8. 8. Graber’s   General Factors Local Factors www.indiandentalacademy.com
  9. 9. General Factors         Heredity Congenital Defects Environment Predisposing Metabolic Climate and Disease Dietary Problems Abnormal Pressure Habits and Functional Aberrations Posture Trauma and Accidents www.indiandentalacademy.com
  10. 10. Local Factors            Anomalies of Number of teeth Anomalies of Tooth Size Anomalies of Tooth Shape Abnormal Labial Frenum; mucosal barriers Pre mature Loss Prolonged Retention Delayed eruption of Permanent Teeth Abnormal Eruptive Path Ankylosis Dental Caries Improper Dental Restorations www.indiandentalacademy.com
  11. 11. Orthodontic Equation  Dockrell.R  Cause acts for specific period of Results Time on a particular www.indiandentalacademy.com Tissue produces
  12. 12. Heredity   Genetically homogenous population tend to have normal occlusion as the Melanesians of the Philippine islands, in whom the malocclusion is almost non-existent. In heterogenous population , the incidence of jaw discrepancies and occlusal disharmonies is significantly greater. www.indiandentalacademy.com
  13. 13. Role of homeobox genes These genes are known to play a role in patterning the embryonic development. These are master genes of head and face controlling patterning , induction, programmed cell death and epithelial mesenchymal interactions. Important genes in craniofacial development include Hox group, Msx1 & Msx2, Dlx, Otx, Gsc and Shh. Two major groups of regulatory proteins including mesenchymal growth factors, BMPs and steroids/ thyroid/ retinoid group are the vehicles through which Hox genes information is expressed. (The heritability of malocclusion:part1; P.A. MOSSEY, British Journal of orthodontics/vol.26/1999/103-113) www.indiandentalacademy.com
  14. 14. Horowitz etal.(1960) studied fraternal and identical adult twin pairs using only linear cephalometric measurements, and he demonstrated highly significant hereditary variations in the anterior cranial base, mandibular body length, lower face height, and total face height.. ( P.A. Mossey, British journal of orthodontics, vol. 26/1999/195-203).  Primary sites affected by genetically transferred dentofacial deformities – – – – Neuromuscular system Dentition Bone & Cartilage Soft Tissues (except muscles) www.indiandentalacademy.com
  15. 15. Neuromuscular system  Consist anomalies in – size, position, tonicity, contractility and neuromuscular coordination pattern of facial, oral & tongue musculature www.indiandentalacademy.com
  16. 16. Lip deformities    The lower lip plays more important role than the upper lip in function movements and in governing the position of lower incisors in normal function during swallowing, speech & smiling.  The inherited pattern of lips can result in malocclusion. Abnormalities in lip form and lip line can cause malocclusion. www.indiandentalacademy.com
  17. 17. Tongue deformities Tongue Size : Macroglossia Microglossia Tongues Positions In case of incompetent lips, tongue protrudes between the teeth to touch the lower lips. This allows nasal breathing n prevents full vertical development of incisors leading to open bite. www.indiandentalacademy.com
  18. 18. Dentition Heredity is the main cause of abnormality in dentition.Twin studies have shown that tooth crown dimensions are strongly determined by heredity (Osborne etal, 1958)*. The molecular genetics of tooth morphogenesis with the homeostatic Hox 7 and Hox 8 (now referred to as MSX1 and MSX2) genes being responsible for stability in dental patterning is confirmation of Butler’s field theory (1963)*. (The heritability of malocclusion:part 2;P.A. Mossey, British Journal of Orthodontics/vol.26/ 1999/195-203)  Abnormalities – – – – Size, shape, number of teeth Mineralization of teeth Path of eruption in primary position of tooth germ Sequence of eruption www.indiandentalacademy.com
  19. 19. Size  Microdontia  Macrodontia www.indiandentalacademy.com
  20. 20. Shape Gemination Twinning Fusion www.indiandentalacademy.com
  21. 21. Number Hypodontia MSX1 & PAX9 genes are found to be involved in some families with non-syndromic autosomal dominant hypodontia . 1 Hyperodontia Supernumary teeth,most frequently seen in premaxillary region with male sex predilection, are also genetically determined www.indiandentalacademy.com 2
  22. 22. Mineralisation  Inherited defects differ from exogenic induced disturbances – present in both deciduous & permanent teeth – localized in either enamel or dentin – arranged irregularly or as vertical ridges & grooves www.indiandentalacademy.com
  23. 23. Bones & Cartilage   Bone morphology or growth alter occlusal relation & functioning Factors – – – –  Bone size Shape of jaw bases Bone location Number of bones present Inherited skeletal malocclusions – – – – – Class II, division 2 Mandibular Prognathism Bimaxillay protrusion Skeletal open bites www.indiandentalacademy.com Mandibular retrognathism
  24. 24.  …rotational growth of mandible resulted from the condylar growth pattern and this would be under genetic control..* …forwardly rotated mandible is largely responsible for strong chin, hypodivergent angular relationship of mandible with cranial base and deep, restrictive over bite.*  …atleast three hard-tissue anatomic features with generally accepted hereditary bases: small tooth size, abundant mandibular basal growth, strong chin.*  Inheritance of a complex occlusal variation in Angle’s class II division 2 malocclussion may actually be polygenic and additive in nature , through combined expression of genetically determined anatomical components, rather than being the effect of a single controlling gene for the entire occlusal malformation.* *(classII division 2 malocclusion: A heritable pattern of small teeth in welldeveloped jaws. Sheldon peck, Angle 0rthodontist vol.1;9-20;1998) www.indiandentalacademy.com
  25. 25. Bone size   Macrognathism Micrognathism – Hypolasia of jaws occurs with craniofacial dysostosis, cleidocranial, dysostosis & crouzon’s diseases www.indiandentalacademy.com
  26. 26. Bone Location  Prognathism – Mandibular prognathism and class II division 2 are attributed to dominant inheritance. – Best known example of familial mandibular prognathism is referred to as the Hapsburg jaw.  Retrognathism www.indiandentalacademy.com
  27. 27. Soft Tissues Anomalies of Frenum Hemifacial microsomia Ankyloglossia www.indiandentalacademy.com
  28. 28. Genetic Syndromes          Achondroplasia Pierre Robin syndrome Craniofacial dysostosis Treacher Collins syndrome Down’s syndrome Gardner’s syndrome Marfan syndrome Heredity ectodermal dysplasia Cleidocranial dysplasia www.indiandentalacademy.com
  29. 29.  Achondroplasia Autosomal dominant characterstics. Failure of synchondrosis leads to underdevelopment of midface because the upper jaw is not translated forward by normal lengthening of the cranial base. This results in Class III malocclusion.  Pierre Robins syndrome Triad of features are: Glossoptosis Cleft palate Micrognathia This results in Class II malocclusion. www.indiandentalacademy.com
  30. 30.  Craniofacial dysostosis Transmitted as autosomal dominant trait. Premature craniosynostosis with or without syndactyly. Hypoplasia of maxilla with mandibular prognathism and a high arched palate, parrot’s beak nose  Treacher Collins syndrome Hypoplasia of facial bones Macrostomia, high palate, abnormal position of teeth Bird like or fish like facies. www.indiandentalacademy.com
  31. 31.  Down syndrome Features include: - Macroglossia, fissured tongue, or pebbly tongue. - High arched palate. - Enamel hypoplasia, microdontia. - Severe periodontitis  Gardner’s syndrome - Multiple impacted supernumerary teeth - Multiple Polyposis of large intestine - Osteoma of bones - Multiple Epidermoid cysts - Desmoid tumors www.indiandentalacademy.com
  32. 32.  Marfan syndrome – – – –  Autosomal dominant trait Defective organization of collagen. Long and narrow face Hyperextensibility of joints High arched palatal vault Multiple odontogenic cysts Hereditary ectodermal dysplasia X-linked recessive – Hypohidrosis – Hypotrichosis – Hypodontia www.indiandentalacademy.com
  33. 33. Cleidocranial dysostosis    Unilateral or bilateral , partial or complete absence of clavicle. Delayed closure of cranial suture, maxillary retrusion, Mandibular protrusion , retarded eruption of permanent teeth, retained deciduous teeth & supernumary teeth. Mutations have been found in core binding factor 1 gene(CBFA1). www.indiandentalacademy.com
  34. 34. 2 1 3 www.indiandentalacademy.com 4
  35. 35. Congenital Deformities  Caused by developmental damage during fetal period (Moss 1967, Enlow 1982) – – – – Cleft lip & Palate Cerebral palsy Torticollis Congenital syphilis www.indiandentalacademy.com
  36. 36. Cleft lip & Palate      Most frequent congenital deformity Incidence 1:700 live births Can be caused by the use of teratogens like , aspirin, dilantin, 6-mercaptopurine, valium and cigarette smoke. In Unilateral cleft, teeth on the affected site are in lingual cross bite Teeth are frequently crowded in cleft www.indiandentalacademy.com
  37. 37. 1.a 2.a 1.b www.indiandentalacademy.com 2.b
  38. 38. Cerebral palsy    Paralysis or lack of muscular coordination attributed to intracranial lesion Commonly result of birth injury Lack of motor control causes abnormal function in mastication ,deglutition ,respiration & speech. Thus affects normal occlusion . www.indiandentalacademy.com
  39. 39. Torticollis or Wry neck  Malocclusion & alteration in morphology of cranium & face is caused due to foreshortening of sternomastoid muscle. www.indiandentalacademy.com
  40. 40. Congenital syphilis       Peg shaped laterals Mulberry molars Notched incisors Enamel hypoplasia Delayed eruption Narrow maxillary arch www.indiandentalacademy.com
  41. 41. Environment    Phenotypes are products of genotypes and the ultimate product is blend of inheritance potential as it has been modified by a dynamic environment. Prenatal influence Postnatal influence www.indiandentalacademy.com
  42. 42. Prenatal influence   Uterine posture , fibroids of mother , amniotic lesions German measles , maternal diet , metabolism , drug like thalidomide induced deformities www.indiandentalacademy.com
  43. 43.   ‘ Vogelgesicht’ , inhibited growth of mandible due to ankylosis of TMJ Intrauterine pressure or trauma cause hypoplasia of mandible www.indiandentalacademy.com
  44. 44. Postnatal influence    Forceps delivery can injure the TMJ Disabling accidents produces malocclusion Milwaukee braces wear produces malocclusion – Maxillary incisors are tipped labially – Mandibular incisors fit into deep palatal grooves www.indiandentalacademy.com
  45. 45. Predisposing metabolic climate & disease    Exanthematous fever disturbs developmental time table and often leave permanent marks on surfaces of teeth. Endocrine disorders Infectious diseases www.indiandentalacademy.com
  46. 46. Endocrine disorders   Prenatally , manifest as hypoplasia of teeth. Postnatally , retard or hasten , but do not disrupt the direction of facial growth. May affect the rate of ossification of bone , eruption of teeth & resorption of primary teeth. www.indiandentalacademy.com
  47. 47. Hyperpituitarism Hypopituitarism Accelerated development of mandible Accelerated development & eruption Enlarged tongue and facial structure Hypercementosis Retarded growth Decreased linear facial measurement Decreased cranial base measurement Open bite Delayed tooth eruption Incomplete root formation www.indiandentalacademy.com
  48. 48. Hyperthyroidism Hypothyroidism Heat intolerance Accelerated skeletal growth Increased vertical face height Open bite Mild prognathism Growth retardation Decreased vertical growth of face Decreased cranial base length Anterior open bite Delayed eruption Maxillary protrusion Spacing between teeth www.indiandentalacademy.com
  49. 49. Hyperparathyroidism Demineralisation Mobility of teeth   Hypoparathyroidism Retarded eruption Early exfoliation Enamel defects www.indiandentalacademy.com
  50. 50. Infectious diseases   Nasopharyngeal diseases & impeded nasal breathing. Enlarged adenoids causes – – – – –  Increased anterior facial height narrow and high palate Retroclined incisors Increased lower facial height Open bite & cross bite Gingival and periodontal diseases – Causes loss of teeth www.indiandentalacademy.com – Ankylosis of teeth
  51. 51. Nutritional deficiency Malocclusion caused by disturbed developmental time table in : - Rickets – Vit. D deficiency - Scurvy – Vit. C deficiency - Beri beri – Vit. B1 deficiency  Malocclusion is caused due to  – Premature loss of teeth – Prolonged retention www.indiandentalacademy.com – Poor tissue health 1 2
  52. 52. Protein deficiency Delayed eruption Decreased radicular osteocementum   Vitamin A deficiency Calcification of teeth is affected Retarded eruption General growth is slow www.indiandentalacademy.com
  53. 53. Vitamin C deficiency Disturbed collagen formation Bleeding gums Loosening of teeth Atrophy and disorganisation of odontoblasts Vitamin D deficiency Hypophosphatemia Disturbed calcification www.indiandentalacademy.com
  54. 54. Abnormal pressure habits  Habits are learned patterns of muscle contraction. – – – – Thumb & digit sucking Tongue thrusting Lip biting & sucking Nail biting www.indiandentalacademy.com
  55. 55. Thumb and digit sucking   Habit is considered normal till 3 ½ to 4 years of age. Triad of factors – – – Duration of habit Frequency of habit Intensity of habit www.indiandentalacademy.com
  56. 56. Thumb and digit sucking  Effects of thumb sucking – Proclination of maxillary anteriors – Increased overjet – Lingual tipping of Mandibular incisors – Anterior open bite – Narrow maxillary arch – Upper lip is hypotonic – Hyperactive mentalis www.indiandentalacademy.com activity
  57. 57. Tongue thrusting   Condition in which tongue makes contact with any teeth anterior to molars during swallowing. Effects : – – – – Proclination of anterior teeth Anterior open bite Bimaxillary protrusion Posterior open bite in case of lateral thrust www.indiandentalacademy.com – Posterior cross bite
  58. 58. Lip biting & sucking   Lower lip is turned inward and pressure s exerted on lingual surfaces of maxillary anterior teeth . Effects : – – – – Proclined maxillary anteriors Retroclined mandibular anteriors Hypertonic lower lip Cracking of lips Nail biting  Causes minor local tooth www.indiandentalacademy.com irregularity
  59. 59. Posture    Stoop shouldered child with head hung so that the chin rests on chest may have mandibular retrusion. Child resting his head on his hands or sleeping on his arms , fists can have malocclusion Poor posture accentuates an existent malocclusion www.indiandentalacademy.com
  60. 60. Trauma or accidents   Idiopathic eruptive abnormalities can be caused due to the blows on face and dental areas. Non vital deciduous teeth have abnormal resorption patterns. www.indiandentalacademy.com
  61. 61. References 1.Handbook of orthodontics by Robert E. Moyers 2.Orthodontic diagnosis by T. Rakosi Irmtrud Jonas T.M Graber 3.Orthodontics principles and practice by T.M. Graber 4.Contemporary orthodontics by W.R. Proffit 5.Orthodontics current principles and techniques by T.M Graber R.L Vanarsdall 6.Oral pathology by Shafer www.indiandentalacademy.com
  62. 62. Thank you Thank you Den23.jpg www.indiandentalacademy.com

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