anatomical landmarks for edentulous patients and facial landmarks

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Anatomical Landmarks

Anatomical Landmarks,Physiology And MyologyOf Facial ExpressionDone By: Mohammed AbdulazizSupervised By: Dr Faiza M AbdulAmeer

ContentsIntroductionExtra-Oral Anatomical LandmarksIntra-Oral Anatomical Landmarks-Classification Of Oral Mucosa-Landmarks Of Maxillary Edentulous Arch-Landmarks of Mandibular Edentulous ArchMyology Of Face And Oral CavityPhysiology Of Oral CavityConclusion

IntroductionThe 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 AngelIndication of lip support by upper anterior teeth.Used In jaw-relation clinic to correct the position of wax rim anteriorly90-110 in average.

Interpupillary line + Ala Tragus Line

Canthus Tragus Line

13 mm

Oral Mucosa

Epithelial LayerConnective Tissue layerSub-Mucosa

Types Of Oral MucosaMasticatory MucosaLining MucosaSpecialized Mucosa

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

Lining Mucosathe 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 MucosaSPECIALIZED 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

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Maxillary Anatomical Landmarks

Limiting StructuresLabial FrenumIt contains no muscle and has no action on its own.It should be properly relieved.

Limiting StructuresLabial VestibuleThe 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 FrenumConsist of one or morebands.Influenced by 3 musclesOrbicularis oris (forward)Buccinator (backward)Levator anguli oris (position)

Limiting StructuresBuccal VestibuleBuccal frenum to hamular notch

Limiting StructuresHamular NotchSituated 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 AreaThe 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 PalateThe horizontal part of palate is considered as primary stress bearing area.

Supporting StructuresResidual RidgeThe portion of the alveolar ridge and its soft tissue covering, which remains following the removal of teeth.(GPT-8).

Supporting StructuresPalatal RugaeThis area contributes to the stress-bearing role (secondary stress bearing area) as well as to retention although in a secondary capacity.

Supporting StructuresMaxillary tuberosityIt 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 PapillaThis 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 RapheAdequate 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 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 RidgeIt 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 RidgeSoft 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 OrisThe 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 MuscleWhen 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 MusclesAct 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 Musclesactions of these muscles are important to the prosthodontist, for they are a part of the kinetic chain of the mandibular movement.

Muscles Of MasticationThese 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 MuscleACTIONS 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 PterygoidsThe 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 musclesExtrinsic musclesStyloglossusPalatoglossusGenioglossushyoglossus

Importance of Tongue In ProsthodonticsAfter 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 PalateTensor veli palatini : It influences the denture border in the hamular notchLevator veli palatini: it helps in determining the vibrating line.Palatoglossus: it exerts pressure on the lingual extension of the lower denture mainly when the tongue is moved toward the cheek.Palatopharyngeous The uvula: is unpaired

Classification of soft palate: Houses 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 CavityPhysiology Of MusclesPhysiology Of BoneSaliva

Physiology Of Muscles

Physiology Of Muscles

IsotonicRelaxationIsometric

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-Osteoporosis2-Hyperthyroidism

Anatomical factor

Prosthodontic factorIntensive denture wearUnstable occlusal contactImmediate denture treatment

Functional FactorLoss of stimulation is essential in accelerating the bone resorption.

Metabolic and systemic factors:OsteoporosisHyperthyroidism

SalivaSaliva is a watery substance formed in the mouth.Human saliva comprises 99.5% mostly water, plus electrolytes, mucus, white blood cells, epithelial

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