Landmarks for maxilla and mandible

7/28/2019 Landmarks for maxilla and mandible

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Anatomical Landmarks of

maxilla and mandible


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Anatomical landmarks What is landmark?

It is an object which is significant and important

The role of making denture is to replace function andappearance and create a restoration which is inharmony with the oral enviroment, the knowledge oflandmarks of the maxilla and the mandible help us toachieve this role


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Landmarks of the maxilla Labial frenum

Incisive papilla

Labial sulcus

Buccal frenum Buccal sulcus

Rugea area

Palatine raphe

Maxillary tuberosity

Hamular notch

Fovea palatine

Vibrating line


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Landmarks of the mandible Labial frenum

Labial sulcus

Buccal frenum Buccal sulcus

(vestibule)

Lingual frenum

Mylohyoid ridge

Retromolar pad area


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Anatomical landmarks Sulci: the alveolar ridges are defined labially

and buccally by a trough of soft tissues called

the sulcus. The sulcus is formed by thereflection of mucosa overlying the ridges into

the lips and cheeks

The lower alveolar ridge also posses lingualsulculs formed by the reflection of mucosa

into the tissues of the floor of the mouth


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Within the sulcus are seen frenal attachments

which are fibrous bands of mucous membrane

Each the upper and the lower jaw have labialfrenum in the midline area, also each jaw has

two buccal frenam on the premolar area

The lower jaw has lingual frenum on themidline of the lingual sulcus and is attached to

the underside of the tongue


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The palate: the palate in the upper jaw

consists of the hard palate anteriorly and the

soft palate posteriorly


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Retromolar pad area:the mandibular alveolar ridge terminatesdistally in an elevated pad of soft tissues called the retromolar

pad

The tissue covering approximately the anterior third of theretromolar pad is fixed, beyond this the tissue moves duringfunctional movements of the mouth, due to the presence of

muscle tissue


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some of anatomical landmarks are considered limiting, this

means that they guides us to have optimum extension of the

complete denture, therefore to engage maximum surface area

without interupting muscles activity.

If the denture impinge on these landmarks, this will lead to

dislodgment of the denture or soreness upon those areas while

failure to cover the areas up to the limiting structure will

cause decreased retention, stability and support.


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Limiting landmarks in maxilla

1. Labial frenum: the complete denture is limited from the

anterior part by the labial frenum, thus the complete denture

must be grooved anteriorly to produce labial notch, this notch

must be deep enough not to cause interference to the labialfrenum but it should also be closley adapted around the

frenum to provide peripheral seal

2.Labial sulcus (vestibule): it runs from the labial frenum till

the buccal frenum at both sides


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Labial frenum,sulcus and buccal frenum


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3.Buccal frenum:

It needs greater clearance on buccal flange of the denture(the groove should be shallower and wider) than the labial

frenum. 4.The buccal sulcus: extends from the buccal frenum to the

hamular notch area

5.Hamular notch-It is depression situated posterior to the

maxillary tuberosity, the hamular notch limits the extensionof denture base posteriorly and the denture base should notextend beyond this notch, otherwise it will cause truama tothe overlying mucosa(pressure being on the pterygoidhamulus and interference with the pterygomandibular raphae


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Hamular

notch

Buccal

sulcus

Buccal frenum


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6.TheVibrating line-An imaginary line drawn across the

palate that marks the beginning of the movement of softpalate when the patient says ah extending from one hamularnotch to the other hamular notch;lying usually 2mm in frontof fovea palatinae.

The vibrating line defines the posterior extention of the fullyextended maxillary denture base


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Vibrating line

Vibrating line


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Limiting landmarks in the mandible

1.Labial frenum: the most anterior part of the denture base is

grooved by the labial , frenum

2.Labial vestibule -Runs from the labial frenum to the buccal

frenum on each side.Mentalis muscle is quite active in this region

3.Buccal frenum

4.Buccal vestibule- Extends posteriorly from the buccal

frenum to outside back corner of the retromolar pad


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Buccal frenum

labial frenum

Labial sulcus

Buccal sulcus


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5.Lingual frenum

6.lingual sulcus

Distally the lower denture base covers the anterior third of the

7.retromolar pad area only as buccinator fibres are inserted

into the posterior two thirds and therefore moves when

buccinator activity occurs


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Lingual frenum

Lingual sulcus

Mylohyoid groove

Retromolar pad area

Mylohyoidline


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There are also some muscles that sourround and

influence the extension and periphery of the

complete denture

For example in addition to the labial and buccle

frenum, the sulcus, the hamular notch and the

vibrating line, the upper complete denture is limited

by the fibers of the incisivuse labii superiors in thelateral incisors region

These fibers are attached to the orbicularis muscle

and limits the extension of complete denture


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Also in the canine region , there is the orgin of the

levator angulii oris that is also inserted in the

orbicularis muscle

The levator angulii oris limits denture periphery in

the canine region

The zygomatic process limits the periphery of the

denture baseThe buccinator muscle also limits the preriphery of

the denture base in the molar region


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Maxillary denture base periphery (the muscles that

influence the extension of upper denture base)


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Manibular denture perihery

In addition to the labial, buccle lingual frenum and

the sulcus, the periphery of the lower complete

denture is influnced by number of muscles

Lateral to the labial frenum, the periphery of the

lower complete denture is enhanced by the mentalis

muscle that descends to their insertion to the skin of

the chin. Further the periphery is enhanced by themuscles of incisivuse labii inferiors muscle


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More distally it is influenced by the depressor

labii inferiors, the depressor angulii oris

muscle and the tissues overlying thebuccinator muscle


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Mandibular denture base periphery (the muscles that

influence the extension of lower denture base)

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Landmarks for maxilla and mandible