maxilla anatomy Flashcards
objective of complete denture fabrication
to provide a prosthesis that restores lost teeth and associated structures functionally, anatomically and aesthetically as much as possible with preservation of underlying structures and the knowledges of these landmarks help us in achieving our objective
anatomical landmarks are grouped into
limiting structures (blue)
supporting structures (green)
relief areas (red)
limiting structures
(blue)
- Sites that guide us in having an optimum extension of the denture, so as to engage maximum surface area without encroaching upon 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 structure, will imply decreased retention stability and support
supporting structures (stress bearing areas)
red
- Load bearing areas
- Denture should be designed such that most of the load is concentrated on these areas
- Support is the resistance to the displacement towards the underlying structures
relief area
green
- Where there are either resorption under constant load, having fragile structures within or covered by thin mucosa which can be easily traumatised
- The denture should be designed in such a way that the masticatory load is not concentrated over these areas
labial frenum
limiting structure
- Fibrous band covered by mucous membrane
- Extends from the labial aspect of the residual ridge to the lip
- A passive frenum and has no active muscle fibres
- V-shaped notch (labial notch) should be provided very carefully on the denture, which should be narrow but deep enough to avoid interference and should also seat adequately around frenum, if peripheral seal is to be achieved
labial sulcus
limiting structure
- Bounded on one side by teeth, gingiva and residual alveolar ridge and on the other by lips
- Runs from one side of the buccal frenum to the other; dividing in two compartments – left and right – by the labial frenum
buccal frenum
limiting structure
- Fibrous band covered by mucous membrane
- Has the attachment of the following muscles
- Levator anguli oris
- Orbicularis oris
- Buccinator
- Requires greater clearance on buccal flange of the denture (shallower and wider) than the labial frenum
buccal sulcus
limiting structure
- Extends from buccal frenum anteriorly to the hamular notch posteriorly
- Size of the vestibule is dependent upon:
- Contraction of buccinator muscle
- Position of mandible
- Amount of bone loss in maxilla
hamular notch
limiting structure
- Depression situated between the maxillary tuberosity and the hamulus of the medial pterygoid plate
- Soft area of loose connective tissue
- Significance
- Houses the disto-lateral termination of the denture
- Aids in achieve posterior palatal seal
- Overextension causes soreness
- Underextension results in poor retention
vibrating line
limiting structure
- Imaginary line drawn across the posterior part of the palate that marks the division between the moveable and immovable tissue of the soft palate, which can be identified by asking the patient to say ‘ah’
- It is extending from one hamular notch to the other hamular notch, lying usually 2mm in front of the palatine fovea
rugae
supporting structure
- secondary stress bearing area
posterior palate
supporting structure
- primary stress bearing area
tuberosity
supporting structure
- secondary stress bearing area
incisive papilla
relief area
- Midline structure behind the central incisors
- Exit point of nasopalatine nerves and vessels
- Should be relived and if not the denture will compress the nerve or vessels and lead to necrosis of the distributing areas and paraesthesia of anterior palate
crest of alveolar ridge
relief area
palatine fovea
relief area
palatine raphe
relief area
- Extends from incisive papilla to distal end of hard palate
- Median suture area covered by thin submucosa
- Relief is to be provided as it is supposed to be the most sensitive part of the palate to pressure
