Mohammad Zakaria Nassani DDS, PhD

Al-Farabi College for Dentistry and Nursing

Prosthetic Dental Sciences Department

Anatomical Landmarks In Relation to Complete

Denture Construction

Introduction

The knowledge of various maxillary and mandibular

anatomical landmarks is essential for successful design

and construction of complete dentures.

These landmarks:

a) act as positive guides to the limits of the dentures

b) guide in locating various areas of primary functions like

relief areas, primary and secondary stress-bearing

areas, retentive areas, peripheral seal areas, etc.

Introduction

Dentures made with proper understanding of these landmarks help in achieving the objectives of:

Mastication Esthetics Phonetics Preservation of remaining tissues

Landmarks common to maxillary and mandibular

foundations

1. The alveolar ridge: This is a ridge of the bone in

which the teeth, when present, were embedded.

Landmarks common to maxillary and mandibular

foundations

1. The alveolar ridge:

Landmarks common to maxillary and

mandibular foundations

2. Frenum: It is a fibrous fold of mucous membrane

attaching the cheeks and lips to the maxillary and

mandibular mucosa limiting the motion of the cheeks

and lips

There is one labial and two buccal frena.

All the frena must have complete freedom of motion

through the groove or space provided in the denture.

Frenum

Landmarks common to maxillary and

mandibular foundations

3. Vestibule: Labial and buccal vestibules house the labial and buccal flanges of the denture.

Labial vestibule is a space bounded by the labial aspect of the residual ridge, the mucolabial fold and the orbicularis oris muscle. It runs from the labial frenum to the buccal frenum

Buccal vestibule extends from the buccal frenum posteriorly up to the hamular and massetric notches as respectively.

Labial and buccal flanges of a complete denture must be properly extended and contoured for proper lip-support, comfort of the patient, and avoiding dislodgement of the denture.

Labial and buccal vestibules

Maxillary Landmarks

Maxillary Landmarks

1. Incisive papilla: it is a pear-shaped elevation of soft

tissues situated at the midline and covering the incisive or

nasopalatine canal.

Just posterior to the crest of the anterior ridge, is the

exiting point of the nasopalatine nerves and vessels,

which requires a relief in the finished dentures, so as to

avoid burning sensation to the patient.

Maxillary Landmarks

2. Rugae: are raised areas of dense connective tissue

radiating from the median suture in the anterior third of

the hard palate. It is considered a secondary stress bearing

area.

3. Palatine vault: It is formed anteriorly by the hard palate

and posteriorly by the soft palate, and bounded laterally

by lingual surfaces of the alveolar ridge.

Maxillary Landmarks

4. Midpalatine raphe (median suture): It is covered with

mucous membrane and a little submucosal tissue.

It requires a selective relief within the denture to avoid rocking of the

denture .

If relief is not provided, it acts as a fulcrum area and results in

soreness as well as unstable dentures.

If it is very prominent, it is called (Torus palatinus) and surgical

removal is necessary.

Maxillary Landmarks

5. Fovea palatine: These are small pits, found at the

midline, just posterior to the junction of hard and soft

palate, always in soft tissues and are used in the

location of the posterior palatal seal area (post-dam).

Maxillary Landmarks

5. Maxillary Tuberosity: it is a bulbous extension of

the residual ridge in the 2nd and 3rd molar regions,

terminating in the hamular notch (the most distal part

of the maxillary alveolar process)

It should be covered by the denture as it is important

for retention.

Maxillary Landmarks

7. Hamular notch (pterygoid notch): Notch formed by the maxilla

and a part of sphenoid bone, located just posterior to maxillary

tuberosity.

It is used as a landmark for correct extension of the posterior border

of denture.

It is also used as a seal area, since it is filled with soft tissues which

can be compressed as there are no muscles or ligaments to prevent

the placement of extra pressure.

It is disto-lateral termination of the denture base.

Hamular notch (pterygoid notch)

Maxillary Landmarks

8. Vibrating line in posterior palatal seal area:

It is an imaginary line that extends between the fovea palatine and

the hamular notches

It is located in the area at the junction of the soft and hard palate

where movement is seen when the patient says “Ahhhh”.

From this line the posterior extension of the denture is determined

(The distal edge of the denture ends at or before this line).

Vibrating line in posterior palatal seal area

Mandibular Landmarks

Mandibular Landmarks

1. Lingual frenum: It is a fold of mucous membrane

which can be seen when the tongue is raised and

attaches the tongue to the floor of the mouth.

Mandibular Landmarks

1. Lingual frenum:

It is very active and often presents a very broad

attachment close to the crest of the ridge.

It must be accommodated in the denture.

Mandibular Landmarks

2. Alveolingual sulcus: a trench or groove in folds of

mucous membrane found at the lingual aspect of the

mandible

It houses the lingual flange of the denture

Mandibular Landmarks

2. Alveolingual sulcus:

The anterior portion of the lingual flange is called the sublingual crescent area

The length and width of the denture border in this area is critical in maintaining the peripheral seal and is effected by the position of the tongue

The movement of the tongue and displaceability of the floor of mouth determine the length of the flange in this area

Mandibular Landmarks

3. Retromolar pad: It is a small pear- shaped bulge of the

mucous membrane at the posterior end of the mandibular

alveolar ridge.

Mandibular Landmarks

3. Retromolar pad:

It should be included in the impression as a seal area for

the posterior border of the denture and the occlusal plane

should be positioned at the level with the upper two-

thirds of this pad.

Mandibular Landmarks

4. External oblique ridge or line: the bony ridge

running downward from the anterior border of the

ramus of the mandible and outward onto the lateral

alveolar process and body

Mandibular Landmarks

5. Buccal shelf: Buccal shelf is an area between the

crest of the alveolar ridge and the external oblique

ridge - a boney ridge.

Mandibular Landmarks

5. Buccal shelf:

This forms a good support, should always be

included in the basal seat area, and is considered a

primary stress- bearing area.

Mandibular Landmarks

6. Mylohyoid ridge: the region of the lingual surface

of the mandible where the mylohyoid muscle is

attached

Mandibular Landmarks

7. Retromylohyoid space:

Area posterior to the mylohyoid muscle (distal end of

lingual sulcus).

Mandibular Landmarks

8. Masseteric notch: A notch in the distobuccal area of the

denture base accommodates the mesial border of the

massetar muscle, which influences the denture border

during opening and closing of the mouth.

Mandibular Landmarks

9. Masseteric notch:

Over extension of the denture border at this area results in

both soreness and movement of the denture base.

Mandibular Landmarks

10. Mental foramen: Lies on the external surface of the

mandible in between the 1st and the second premolar

region.

Mandibular Landmarks

10. Mental foramen:

It should be relieved specially in case it lies close to the

residual alveolar ridge due to ridge resorption to prevent

parasthesia

Mandibular Landmarks

11. Genial tubercle: a small rounded elevation on the

lingual surface of the mandible on either side of the

midline near the inferior border of the body of the

mandible, serving as a point of insertion for the

geniohyoid muscles

Mandibular Landmarks

11. Genial tubercle:

They are the origins of both genioglossus and geniohyoid muscles.

Lies away from the crest of the ridge.

They do not undergo bone resorption

They project prominently in resorbed ridges.

Adequate denture relief should be provided.

Grouping of the landmarks

Primary stress-bearing areas Secondary stress-bearing areas

Relief areas Border limiting structures

Landmarks of edentulous arches

Anatomically the edentulous arches can be divided

as follow:

Primary stress-bearing areas

The primary stress-bearing areas are those areas which are best suited to resist vertical forces of occlusion

Maxillary Mandibular

1- Crest of the ridge 1-The buccal shelf

2- Flat areas of the palate

Secondary stress-bearing areas

Secondary stress-bearing areas are those areas which by

their histological make-up, or by the nature of their

inclined planes, resist lateral forces of occlusion and can

also aid in the resistance to vertical forces of occlusion

Maxillary Mandibular

1- Lateral slopes of the palate 1- Anterior ridge

2- Rugae 2- All the ridge slopes

3- Labial and buccal surfaces of

the ridge

Primary and secondary stress-bearing areas

Primary and secondary stress-bearing areas

Relief areas

Relief areas are those areas which, when subjected to occlusal

force, either cause discomfort to the patient or instability of the

denture base and eventual resorption of supporting bone.

Maxillary Mandibular

1- Incisive papilla 1- Mental foramen

2- Median palatal raphe 2- Genial tubercles

3- Zygomatic process 3- Sharp mylohyoid ridge

4- Torus palatinus 4- Crest of the ridge

5- Sharp bony prominences 5- Mandibular tori

6- Sharp bony prominences

Relief areas

Relief areas usually have fragile structures or are covered by

thin mucosa which can be easily traumatized & hence

should be relieved.

Maxillary Mandibular

1- Incisive papilla 1- Mental foramen

2- Median palatal raphe 2- Genial tubercles

3- Zygomatic process 3- Sharp mylohyoid ridge

4- Torus palatinus 4- Crest of the ridge

5- Sharp bony prominences 5- Mandibular tori

6- Sharp bony prominences

Relief areas

Border limiting structures

These are the structures that limit the border extent of the

denture

These sites will guide us in having an optimum extension

of the denture so as to engage maximum surface area

without encroaching upon the muscle actions

Encroaching upon these structures will lead to

dislodgement of the denture and/or soreness of the area

while failure to cover the areas up to the limiting structures

will imply decreased retention stability and support.

Border limiting structures

Maxillary Mandibular

1- Labial frenum 1- Labial frenum

2- Labial vestibule 2- Labial vestibule

3- Buccal frenum 3- Buccal frenum

4- Buccal vestibule 4- Buccal vestibule

5- Hamular notch 5- Masseteric notch area

6- Posterior palatal seal area 6- Retromolar pad

7- Lingual frenum

8- Sublingual crescent area

9- Retromylohyoid space

10- Alveolingual fold

Border limiting structures

Border limiting structures

A comparison between edentulous jaws

Maxillary Mandibular

1.Has more supporting areas 1.Has less supporting area.

2.Limiting structures are less in

number and have a less stronger

influence over the denture

border

2.Limiting structures are more

in number and have a stronger

influence over the denture

border

Concluding remarks

A sound knowledge of the anatomical landmarks

of the edentulous jaw is a prerequisite if one has

to achieve the objective of constructing a

complete denture that has maximum retention,

stability and support with preservation of

underlying structures with minimum post

insertion problems.