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Unit II: Oral HealthUniversity of Ottawa Faculty of
Medicine
Dr. B. Carol Janik Chief, Division of DentistryChildren’s Hospital of Eastern Ontario
Dr. Stephanie Lauziere Staff Paediatric DentistChildren’s Hospital of Eastern Ontario
Introduction to theOral Health Component
• Oral wellness and general health have long been considered separately
• Changing perspective: putting the mouth back in the body
• Primary medical care encompasses the whole body
• Physicians: diagnosis of dental disease and oral health promotion
• Dentists: link to medical diagnoses
• Increasing awareness throughout health-related professions
Objectives
List the components of the oral cavity.
Describe the muscles used in mastication and their nerve supply.
Describe the anatomy of the tooth and supporting bone in cross section and the significant features of each component.
Explain and differentiate primary and permanent dentition including normal eruption, timing, occlusion and function.
Recognize the association of dental anomalies with syndromes and identify two such associations.
Functions of the Oral Cavity
Oral Competence
Taste
Mastication
Digestion
Aids in swallowing
Communication
(Respiration)
http://z.hubpages.com/u/255675_f260.jpg
Oral Cavity - boundaries
Begins at the vermillion border of upper and lower lip
Extends to the palatoglossal folds immediately in front of the tonsils
Bounded by the cheeks at the sides
Hard and soft palate form the roof
Bounded below by the floor of the mouth
The upper jaw (maxilla) and lower jaw (mandible) support the teeth http://www.octc.kctcs.edu/gcaplan/anat2/notes/Image463.gif
Oral Cavity - components
Upper and lower dental arches teeth and supporting
structures
Vestibule of the mouth region between the teeth and
inner surface of the lips (labial) and cheeks (buccal)
opening of parotid duct
Oral cavity proper upper and lower dental arches anterior two-thirds of the
tongue submandibular ducts multiple small ducts of
sublingual glandshttp://www.nature.com/bdj/journal/v205/n10/fig_tab/sj.bdj.2008.981_ft.html
Oral Cavity - structures
http://www.pitt.edu/~anat/Head/Mouth/Mouth.htm
Oral Cavity - structures Tongue
anterior anterior two-thirds is visible in the oral cavity
dorsal surface is rough with minute papillae and taste buds
ventral surface is smooth with two thin serrated folds
frenulum controls range of movement
Floor of the mouth forms the roof of the sublingual spaces
lined by mucous membrane
attaches to the inner surface of the body of the mandible where it becomes continuous with the mucoperiosteum of the gum on the lingual side of the teeth
centrally, becomes continuous with the mucous membrane covering the anterior two-thirds of the tongue
freely movable in association with the great mobility of the tongue, except at the mandibular attachment
ducts of submandibular and sublingual salivary glands and numerous mucous glands open
CASE:
A three-year-old boy is brought in by his mother for evaluation of a tongue deformity.
The lingual frenulum is short and thickened and the tongue is notched at the tip.
The mother wonders whether her son's speech problem is related to this condition.
WHAT IS YOUR DIAGNOSIS?http://www.emedmag.com/html/pre/dia/dia/02_04.asp
Ankyloglossia (tongue-tie)
A tongue deformity in which the lingual frenulum appears abnormally short and thick.
In extreme cases causes a fusion of the tongue to the anterior floor of the mouth.
Reported incidence is > 1%.
Probably results from disruption of the formation of the oral vestibule by an ingrowth of ectoderm.
Parents often blame it for articulation disorders, but its actual interference with speech development is reportedly rare.
If the child can protrude the tongue to the incisor teeth, lingual function for speech probably will not be affected.
In the absence of major difficulty with sucking, treatment is usually not indicated before age four, considering the possibilities of bleeding, infection, and scar formation.
http://www.emedmag.com/html/pre/dia/dia/02_04.asp
Oral Cavity - structures
Roof of the mouth Hard palate formed primarily by palatine processes of the maxillary
bones.
Soft palate is a fibromuscular septum that can be moved to close off the nasopharynx.
Cheeks opening of duct of parotid gland (Stensen’s duct)
Mucous membrane stratified squamous epithelium throughout the oral cavity
tightly bound to underlying bone over the alveolar processes and the hard palate forming a mucoperiosteum
firmly attached to the tongue musculature
less firmly attached to the buccinator (cheek) muscle, lip musculature and muscles of the soft palate
more loosely attached to the floor of the mouth and vestibular region, permitting greater freedom of movement of the tongue, cheeks and lips
Oral Cavity - structures Teeth and gums
the alveolar processes of maxilla and mandible support the teeth
gingiva is the mucosa surrounding the tooth that is designed for chewing, attached in part to the cementum of the tooth and in part to the alveolar bone.
Retromolar region extends from the back of the last
lower molar below to the back of the last upper molar above
mucous membrane is firmly attached to the underlying muscle and bone and contains some mucous glands.
http://img.tfd.com/mosby/thumbs/500038-fx14.jpg
http://www.maxillofacialcenter.com/images/pericorTitle.jpg
Oral Cavity – posterior boundary
bounded posteriorly by the palatoglossal folds immediately in front of the tonsils
opens into the oropharynx through the fauces (oropharyngeal isthmus)
http://biology.clc.uc.edu/fankhauser/labs/microbiology/strep_detection/oropharynx_P2253089_lbd.JPG
Anatomy of the tooth and supporting boneCalcified tissues:
enamel dentin cementum
Central pulp cavity: connective tissue blood vessels nerves
Supporting structures: periodontal ligament alveolar bone cementum gingivae
https://www.clarian.org/ADAM/doc/In-DepthReports/10/000024.htm
Enamel extremely hard, highly mineralized, crystalline structure covers and protects the crown surface for chewing, grinding, crushing of food
Dentin bone-like core of the tooth, substructure for rigid enamel unique structure of dentinal tubules
Pulp contains blood vessels and nerves, nourishes the dentin connects to jaw’s vascular and nervous supply through root
apex
Cementum thin calcified covering of the root
Periodontal ligament attaches root to the surrounding alveolar bone of the socket
Alveolar bone thin layer of compact bone that forms the tooth socket
surrounding the roots
The Dentition Development of teeth and arrangement of teeth in the mouth. Comprised of up to four distinct types of teeth, depending on the stage of
development.
Incisors (Cutting teeth) 4 front most teeth per jaw, used for the initial biting of food. straight sharp cutting edge and one root.
Canines (Cuspids) 2 (one each side) per jaw, used with the incisors to bite into/tear food. sharp pointed edge and one root.
Premolars (Bicuspids) 2 on each side per jaw, similar to molars in form and function, used to crush
and grind food. biting surface has two broad cusps, first upper premolars usually have two
roots and other premolars have one root.
Molars 2 or 3 on each side per jaw, larger than premolars, used for crushing and
grinding food. cusped crowns with prominent ridges, three to five cusps and two or three
roots. the third molars (Wisdom Teeth) can become painfully wedged (impacted) behind
the 2nd molars if there is inadequate space for eruption.
http://www.kidzsmile.com/images/tooth-chart-primary.jpg
Dentition - stages
Primary/deciduous~ 6 months to ~ 6
years
Mixed dentition~ 6 years to ~ 12
years
Permanent dentition> 12 years
n = 20 n = variable n = 32
grouped into incisors, canines (cuspids), molars
transitional
grouped into incisors, canines (cuspids), molars, +/- premolars (bicuspids)
grouped into incisors, canines, premolars (bicuspids), molars
smaller, whiter, more prone to wear (to be replaced)
important for maintaining space for the developing permanent dentition
both primary and permanent teeth present in varying proportion
more calcified and stronger than the primary teeth (to last a lifetime)
function for mastication
http://www.kidzsmile.com/images/tooth-chart-permanent.jpg
Occlusion
The way teeth fit together tooth contact and interdigitation bite-relationship
Factors involved in normal occlusal development temporomandibular joint associated neuromusculature teeth
Malocclusion malalignment of teeth (dental malocclusion), crowding,
spacing, tipping, rotation, dental deterioration, anomalies jaw relationship discrepancy (skeletal malocclusion),
airway, low muscle tone, oral habits (thumbsucking)
Arrangement of the Teeth and Occlusion
http://ddskim.com/gd1.htm
Mastication
Chewing action of the teeth brought about by movement of the lower jaw through the muscles of mastication
Stable occlusion Maximum support to the muscles and joint
Unstable occlusion muscles of mastication malfunction
increase in load/pressure on the temporomandibular joint
pain, damage, degeneration
http://www.parkchambersdental.co.uk/jaw_pain.htm
Temporomandibular Joint (TMJ) Synovial joint; mandible articulates with the base of the skull
(temporal bone)
Allows functional movement of the mandible, eating, speaking, etc.
Function may be affected by the way teeth occlude
Components: Mandibular condyle
round end of mandible; translates, rotates during function
Temporal fossa socket where condyle fits; concave
Articular eminence convex; condyle translates during movement
Articular disc (meniscus) cartilage-like dense collagen; between condyle and fossa divides joint into two compartments
Ligaments hold disc to the condyle; help stabilize the joint
Connective tissue holds disc to back of the joint; contains blood vessels and nerves forms capsule that surrounds the joint
Muscles of Mastication
A set of complex muscles surrounding the TMJ Masseter
Temporalis
Lateral Pterygoid
Medial Pterygoid
When relaxed and flexible, they work harmoniously with other components of the TMJ complex for proper function.
Masseter muscle Origin
zygomatic arch/zygomatic bone
Insertion lateral surface of ramus and angle of mandible
Nerve supply masseteric nerve from mandibular division of trigeminal nerve V
Action elevates mandible powerful chewing muscle
http://anatomy.med.umich.edu/nervous_system/infratemp_tables.html
Temporalis muscle Origin
temporal fossa/temporal fascia
Insertion coronoid process and anterior surface of ramus of mandible
Nerve supply anterior and posterior deep
temporal nerves from mandibular division of trigeminal nerve V
Action elevates mandible retracts mandible a powerful chewing muscle http://anatomy.med.umich.edu/nervous_system/infratemp_tables.html
Lateral Pterygoid muscle Origin
superior head: greater wing of sphenoid
inferior head: lateral surface of lateral pterygoid plate
Insertion superior head: capsule &
articular disc of TMJ inferior head: Neck of
mandible Nerve supply
lateral pterygoid branch of mandibular division of trigeminal nerve V
Action protracts mandible, opens
mouth *The only one of the muscles
of mastication that opens the mouth
http://anatomy.med.umich.edu/nervous_system/infratemp_tables.html
Medial Pterygoid muscle Origin
Medial surface of the lateral pterygoid plate, pyramidal process of palatine bone, tuberosity of maxilla
Insertion Medial surface of ramus and
angle of mandible Nerve supply
Medial pterygoid branch of mandibular division of trigeminal nerve V
Action Elevates and protracts
mandible *Mirrors the masseter m. in
position and action with the ramus of the mandible between
http://anatomy.med.umich.edu/nervous_system/infratemp_tables.html
Oral Cavity – role in digestion
the oral cavity is the beginning of the gastrointestinal tract.
during mastication, saliva moistens and compacts the chewed food while the tongue rolls it into a bolus.
saliva contains digestive enzymes (eg. salivary amylase) which begin the breakdown of carbohydrates.
chewing increases the surface area of foods which helps to accelerate the breakdown of starch molecules into simple sugars by the digestive enzymes.
the bolus is pushed to the back of the oral cavity for swallowing and the soft palate involuntarily closes off the nasal cavity.
Dental Anomalies
Variations in normal oral structures and dental anomalies can be detected as part of a thorough physical examination which includes the oral cavity.
Dental anomalies can interfere with proper oral function and impact health.
Number
Structure
Size
Shape
Dental Developmental Stages Initiation
Dental lamina activity Anomalies of tooth number
Proliferation Development of epithelial enamel organ and formative organ of dentin
and pulp Anomalies of tooth number and size
Histodifferentiation Continued development of tissues essential for enamel production Anomalies of enamel structure
Morphodifferentiation Differential growth establishes basic form and relative size Anomalies of size and shape
Apposition Rhythmic deposition of matrix of enamel, dentin and cementum Anomalies of structure
Maturation Mineralization Anomalies of enamel quality
Anomalies of Tooth Number
Supernumerary Teethextra teeth
Oligodontiacongenitally missing teeth
http://www.cda-adc.ca/jcda/vol-67/issue-10/graphics/Fig2_4459.jpg http://www.ispub.com/ispub/ijds/volume_3_number_2_11/nonsyndromic_oligodontia_in_permanent_dentition_three_siblings/dentition-fig1.jpg
Anomalies of Tooth Structure
Amelogenesis Imperfecta• Heritable enamel defect
Dentinogenesis Imperfecta• Heritable dentin structure abnormality• May occur with Osteogenesis Imperfecta
http://shw.effa007.fotopages.com/9162913/dentinogenesis-imperfecta-translucent-appearance-of-teeth.html
http://www.ojrd.com/content/2/1/17
Anomalies of Tooth Shape / Size
Conical supernumerary toothTalon cusp
http://cudental.creighton.edu/images/talon%20cusp%20lateral.jpg http://www.woosk.com/wp-content/uploads/2009/03/tooth.jpg
Conditions with Associated Dental Anomalies
Turner’s syndrome enamel hypoplasia
Ehlers-Danlos syndrome irregular dentin tubules with inclusions intrapulpal calcifications
Cleidocranial dysplasia delayed exfoliation of primary, delayed eruption of
permanent teeth supernumerary teeth roots lack cellular cementum
Cleft Lip/Cleft Palate congenitally missing teeth supernumerary teeth enamel hypoplasia
Down Syndrome (trisomy 21)
Dental Anomalies: Microdontia
Enamel hypoplasia
Oligodontia
Supernumerary teeth
Tooth morphology
Rotated teeth
Delayed eruption
Ectodermal Dysplasia
Dental anomalies:
Abnormal development of skin, hair, nails, teeth, sweat glands
Conical crowns
Oligodontia
Maxillary hypoplasia
Delayed eruption
http://www.nature.com/bdj/journal/v194/n5/full/4809925a.html
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0365-05962009000200015&lng=es&nrm=1&tlng=en
http://www.ispub.com/ispub/ijds/volume_7_number_2_20/prosthodontic-treatment-of-a-patient-with-ectodermal-dysplasia-a-case-report/dysplasia-fig3.jpg
How did we do? … a look back at the objectives
List the components of the oral cavity
Describe the muscles used in mastication and their nerve supply
Describe the anatomy of the tooth and supporting bone in cross section and the significant features of each component
Explain and differentiate primary and permanent dentition including normal eruption, timing, occlusion and function
Recognize the association of dental anomalies with syndromes and identify two such associations
Resources American Head & Neck Society. Oral Cavity Cancer.
<http://www.ahns.info/patienteducation/docs/oralcavity.php>
AnneCollins.com Digestion in the Mouth: A Short Guide. 2007. <http://www.annecollins.com/digestive-system/mouth-digestion-guide.htm>
British Dental Association 3D Mouth. Dental Anatomy. 2004. <http://www.3dmouth.org/4/4_intro.cfm>
Caspary G, Krol DM, et al. Perceptions of Oral Health Training and Attitudes Toward Oral Health Screenings Among Graduating Pediatric Residents. Pediatrics 2008; 122 (August):e465-e471.
DentalFind.com—Cosmetic Dentistry Resources. Dental Glossary. 2008. <http://www.dentalfind.com/glossary/>
Epstein, Melvin H. MD, et al. “The Johns Hopkins Atlas of Human Functional Anatomy: Fourth Edition”. The Head and Neck. Ch. 15, page 73. The Johns Hopkins University Press, Baltimore and London.
“The Handbook”. American Academy of Pediatric Dentistry Publication.
The University of Michigan Medical School. Medical Gross Anatomy Learning Resources: Anatomy Tables/Lecture Notes/Dissector Answers—Infratemporal Fossa & Oral Cavity. 2000. <http://anatomy.med.umich.edu/nervous_system/infratemp_tables.html>
Youn W. Park, MD, Mark Matthews, MD. Emergency Medicine. Diagnosis at a Glance. 2009. <http://www.emedmag.com/html/pre/dia/dia/02_04.asp>
For further information:
Dr. B. Carol Janik
Dr. Stephanie Lauziere