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

cjanik@cheo.on.ca

Dr. Stephanie Lauziere

slauziere@cheo.on.ca