Anatomical Landmarks,Physiology And

MyologyOf Facial

Expression

Done By: Mohammed AbdulazizSupervised By: Dr Faiza M AbdulAmeer

Contents… Introduction Extra-Oral Anatomical Landmarks Intra-Oral Anatomical Landmarks

-Classification Of Oral Mucosa-Landmarks Of Maxillary Edentulous Arch-Landmarks of Mandibular Edentulous Arch

Myology Of Face And Oral Cavity Physiology Of Oral Cavity Conclusion

Introduction…

The good knowledge of anatomy and physiology is a keystone in getting the best result during the fabrication of any prosthesis, this best result is which restores the missing oral parts and preserves what is remaining.

Facial Anatomical Landmarks

Effects Of Edentulism on face:1-2-

Eye

Ear

Nose

Lips

Folds (Grooves)

Naso Labial Angel

Indication of lip support by upper anterior teeth.

Used In jaw-relation clinic to correct the position of wax rim anteriorly

90-110 in average.

Interpupillary line + Ala Tragus Line

Canthus Tragus Line

13 mm

Oral Mucosa

Epithelial Layer

Connective Tissue layer

Sub-Mucosa

Types Of Oral Mucosa

Masticatory Mucosa

Lining MucosaSpecialized Mucosa

Masticatory Mucosa

Free, attached gingiva and hard palate comes in primary contact with food during mastication and is keratinized.

Lining Mucosa

the lips cheeks, vestibule, floor of the mouth, ventral surface of the tongue and soft palate. It does not function in mastication. It is soft, pliable and non-keratinized. 

Specialized Mucosa

SPECIALIZED MUCOSA: on the dorsal surface (dorsum) of the tongue. It is covered with cornified epithelial papillae.

Intra Oral Anatomical Landmarks

Maxillary Anatomical LandmarksMandibular Anatomical

Landmarks

Maxillary Anatomical Landmarks

a} Limiting structures

- Labial frenum

- Labial vestibule

- Buccal frenum

- Buccal vestibule

- Hamular notch

- Posterior palatal seal area     

b} Supporting structures-Hard palate -Residual ridge -Palatal rugaeMaxillary Tuberosity

c} Relief areas- Incisive papilla- Mid palatine raphe- Canine Eminence- Fovea palatine - Palatal Tori

Limiting StructuresLabial Frenum It contains no muscle and has

no action on its own. It should be properly relieved.

Limiting StructuresLabial Vestibule The labial vestibule is divided

into a left and right labial vestibule by the labial frenum and extends upto the buccal frenum on either side.

The main muscle of the lip, which forms the outer surface of the labial vestibule, is the orbicularis oris.

Limiting StructuresBuccal Frenum Consist of one or more bands. Influenced by 3 muscles

Orbicularis oris (forward) Buccinator (backward) Levator anguli oris (position)

Limiting StructuresBuccal Vestibule Buccal frenum to hamular

notch

Limiting StructuresHamular Notch Situated between the

tuberosity and hamulus of the medial pterygoid plate.

Distal extension of denture. If the denture extends too far

into the hamular notch, the mucous membrane covering the raphe will be traumatized.

Anterior Vs Posterior Vibrating lines

Limiting StructuresPosterior Palatal Seal Area The soft tissue area at or

beyond the junction of the hard and soft palates on which pressure,within physiologic limits, can be applied by a denture to aid in its retention”. (GPT-8).

Posterior palatal seal has several advantages.

Supporting StructuresHard Palate The horizontal part of palate is

considered as primary stress bearing area.

Supporting StructuresResidual Ridge “The portion of the alveolar

ridge and its soft tissue covering, which remains following the removal of teeth”.(GPT-8).

Supporting StructuresPalatal Rugae This area contributes to the

stress-bearing role (secondary stress bearing area) as well as to retention although in a secondary capacity.

Supporting StructuresMaxillary tuberosity It is considered as secondary

stress bearing area, if it is firm it can withstand more forces.

Sometimes it is oversized either with soft tissue or with bone.

Combination Syndrome

Relief areasIncisive Papilla This covers the incisive

foramen and is located in the midline immediately behind and between central incisors.

Care should be taken that the denture base does not impinge on them and hence should be relieved.

Relief areasMid Palatine Raphe Adequate relief should be

provided in this area as, mucosa covering the raphe is extremely thin and is traumatized easily.

Relief areasCanine Eminence

Relief areasFovea Palatine

Relief areasPalatal Tori

Mandibular Anatomical Landmarks

Limiting structures

- Labial frenum-Labial vestibule -Buccal frenum-Buccal vestibule-Lingual frenum-Alveololingual sulcus-Retromolar pad

Supporting structures-buccal shelf area.-residual alveolar ridge.

Relief areas

-mental foramen.

-genial tubercle.

-Mylohyoid ridge.

-Torus mandibularis.

Limiting StructuresLabial Frenum

Limiting StructuresLabial Vestibule

Limiting StructuresBuccal Frenum

Limiting StructuresBuccal Vestibule

Limiting StructuresLingual Frenum

Limiting StructuresAlveololingual sulcus

Limiting StructuresRetromolar Pad

Supporting StructuresBuccal Shelf Area It is considered as primary

stress bearing area. It is horizontal and made up of

dense cortical bone.

Supporting StructuresResidual Alveolar Ridge It is considered as secondary

stress bearing area (lateral slopes).

The crest of the ridge should be relieved.

Relief AreasMental Foramen

Relief AreasGenial Tubercle

Relief AreasMylohyoid Ridge Soft tissue usually hides the

sharpness of mylohyoid ridge. The mucous membrane

overlying the sharp or irregular mylohyoid ridge needs to be relieved.

Relief AreasTorus Mandibularis

Is it time for restAny energy remained

Myology Of Face And Oral Cavity -Physiology Of Muscles -Muscles Of Facial

Expression -Sopra-Hyoid Muscles -Infra-Hyoid Muscles -Muscles Of Mastication -Muscles Of The Tongue -Muscles O Soft-Palate

Muscles Of Facial Expression

Modiolus

Modiolus

Muscles Of Facial ExpressionBuccinator Is a thin quadrilateral muscle,

occupying the interval between the maxilla and the mandible at the side of the face. It forms the anterior part of the cheek or the lateral wall of the oral cavity.

Muscles Of Facial ExpressionBuccinator

Muscles Of Facial ExpressionOrbicularis Oris “The orbicularis oris muscle is a

complex of muscles in the lips that encircles the mouth. Until recently, it was misinterpreted as a sphincter, or circular muscle, but it is actually composed of four independent quadrants that interlace and give only an appearance of circularity.”

 Saladin, "Anatomy & Physiology: The Unity of Form and Function". 5th edition. McGraw Hill. Page 330

Muscles Of Facial ExpressionMentalis Muscle When contracts it can dislodge

the denture. It dictates the level of

extension of the labial flange of mandibular denture.

Reduce the lower labial vestibule when it contracts.

Supra-Hyoid Muscles

Act in elevating the hyoid bone and larynx and depression of the mandible.

The mylohyiod and geniohyiod may influence border of mandibular denture.

The mylohyoid constitutes the floor of the mouth.

Infra-Hyoid Muscles

actions of these muscles are important to the prosthodontist, for they are a part of the kinetic chain of the mandibular movement.

Muscles Of Mastication

These muscles have masticatory and non-masticatory movements, but in concern of complete denture, the non-masticatory movements have more influence on denture borders. Also these muscles especially the temporalis aid in obtaining centric relation.

Muscles Of MasticationTemporalis Muscle ACTIONS OF TEMPORALIS - Elevates the mandible, this

movement requires both the upward pull of anterior fibers and backward pull of the posterior fibers.

- Posterior fibers draw the mandible backwards after it has been protruded.

Muscles Of MasticationMasseter Muscle

ACTIONS OF MASSETER: Elevates the mandible to close

the mouth and to occlude the teeth in mastication.

It has a small effect in side-to- side movement, protraction and retraction.

Muscles Of MasticationMedial And Lateral Pterygoids The fibers of the lateral

pterygoid, pull the mandible forwards (protrusion) and medially.

The fibers of the medial pterygoid also perform the same actions in addition elevate the mandible.

Muscles Of The Tongue

Intrinsic muscles Extrinsic muscles

Styloglossus Palatoglossus Genioglossus hyoglossus

Importance of Tongue In Prosthodontics After loss of teeth, tongue

expands into the space created by lost teeth, this enlargement make the impression more difficult, and reduce the stability of denture.

The level of occlusal table in relation to tongue level is so important because high occlusal level reduces the retention of denture, while low occlusal level contributes in tongue biting during function.

Muscles Of Soft Palate

1. Tensor veli palatini : It influences the denture border in the hamular notch

2. Levator veli palatini: it helps in determining the vibrating line.

3. Palatoglossus: it exerts pressure on the lingual extension of the lower denture mainly when the tongue is moved toward the cheek.

4. Palatopharyngeous 5. The uvula: is unpaired

Classification of soft palate: House’s classification

Class I: the soft palate is almost horizontal curving gently downwards

Class II: the soft palate turns downward at about 45 angle from the hard palte

Class III: the palate turns downward sharply at about 70 angle to the hard palate.

Physiology Of Oral Cavity

Physiology Of Muscles Physiology Of Bone Saliva

Physiology Of Muscles

Physiology Of Muscles

Isotonic

Relaxation

Isometric

Physiology Of Bone

The reduction of bone may occur due to: -Anatomical factor -Prosthodontic factor (pressure

mediated resorption ) -Functional Factor -Metabolic and systemic factor:

1-Osteoporosis 2-Hyperthyroidism

Anatomical factor

Prosthodontic factor

Intensive denture wear Unstable occlusal contact Immediate denture treatment

Functional Factor

Loss of stimulation is essential in accelerating the bone resorption.

Metabolic and systemic factors:

Osteoporosis Hyperthyroidism

Saliva

Saliva is a watery substance formed in the mouth.

Human saliva comprises 99.5% mostly water, plus electrolytes, mucus, white blood cells, epithelial cells (which can be used to extract DNA), glycoproteins, enzymes, antimicrobial agents such as secretory IgA and lysozyme

Roles Of Saliva

Lubrication Digestion Role In Taste Immune Other ( In prosthodontics )

Major Salivary Glands

Parotid Submandibular Sublingual

They produce about 90 % of total salivary production.

Minor Salivary Glands

Labial, buccal and lingual mucosa

Soft palate Lateral parts of hard palate Floor of the mouth

The produce about 10 % of saliva.

Sialorrhea

Excessive production of saliva (hypersalivation).

Make impression procedure more difficult.

May occur temporarily after insertion of denture.

Xerostomia And Hyposalivation

Injury due to losing lubricant abilities of saliva.

Loss of retention

Causes Treatment

Conclusion

Thank You For Listening