4. Medical history & General Principles Flashcards
Age and adaptability to new prostheses?
Worse adaptability due to worse tissues
What size lips are better when assesing a patient for dentures?
bigger lips
What happens to the floor of the mouth of an edentulous patient?
- Goes up due to progressive resorption of the ridge
What restricts the extension of the dentures base?
Mobile tissues insertion
What happens to the VD of an edentulous patient? (2)
-reduced b/c lack of teeth - mandible goes up to get in contact with maxilla
What supplemental exams are needed for dentures? (3)
• Orthopantomogram. - Impacted teeth. - Cysts. - Remaining roots. • Periapical radiographs. • Computerized tomography, nuclear magnetic tomography, biopsy, sialography.
Two kinds of forces act upon a complete denture:
- Passive forces: Forces while the mouth is at rest. - Functional forces: Forces while in function (chewing, swallowing, talking, drinking…)
Displacement forces of a denture? (3)
• Intrussive forces: Tend to impact the denture over the supporting structures. • Extrussive forces: Tend to move the denture out of place. *dentures must be capable of minimizing this forces
Opposing forces for displacement of a denture? (3)
• Support » opposes to intrusive forces. • Retention and stability » oppose to extrusive forces. - Retention: opposes all vertical extrusive forces. - Stability: opposes all lateral extrusive forces.
Define Support (3)
- relationship b/w denture base and supporting tissues -opposes intrusive forces - surface of denture
Define retention
- Resisting the forces of dislodgment along the path of placement - opposes all vertical extrusive forces.
Define stability
opposes all lateral extrusive forces.
What bears the load in complete dentures? (2)
- always tissue-supported, although in the end bone is what bears the load - Attached gingiva and bone are the supporting structures, but support is the capability of the denture
Bad support is implied by? (2)
- Bad supporting tissue (ex. mobile gingiva) - bad denture fit
What factors are involved in retention? (4)
• Adhesion. • Cohesion. • Border seal. • Other factors.
Define adhesion: (2)
-property of remaining close in proximity - physical attraction of molecules of DIFFERENT bodies
How does adhesion occur with dentures? (2)
- Between denture and saliva - Between saliva and mucosa.
Adhesion related to space between denture and mucosa?
-wider space = less adhesion = less retention
What factors increase adhesion (Retention)? (3)
- more supporting surface of denture - thicker saliva **TOO thick saliva can hinder impression taking by increasing hydraulic pressure between denture and mucosa
Define cohesion:
sticking together of particles of the SAME substance
What causes higher retention in relation to cohesion? (3)
- More Saliva b/c located between the denture and supporting mucosa - more saliva cohesion = more surface tension = more retention - more supporting surface of denture = higher retention
Does the upper or lower denture have more retention? (2)
Upper. -lower= less retention b/c of cohesion and adhesion
Define border seal: (2)
- Contact of the denture border with the underlying or adjacent tissues to prevent the passage of air or other substances - a negative pressure at inner surface of denture (vacuum)
Border seal is also know as?
Peripheral seal
Dentures: Border seal and force? (3)
-implies increase in force needed to remove - force doesnt exist if theres a hole - better fit = better seal - bigger extension of base = more negative pressure = more retention
Certain elements designed to increase retention must be avoided: why? (3)
• Suction chambers. • Suction cups. Can produce tissue hypertrophy
What is hypertrophy?
Increase in the volume of an organ or tissue (# of cells increase)
Define stability:
Dental prosthesis to be firm, steady, or constant, to resist displacement by functional horizontal or rotational stresses
______ & ______ can help denture stability
Support and retention
Stability is mainly achieved by….?
balanced articulation
What is balanced articulation?
Bilateral, simultaneous, anterior, and posterior occlusal contact of teeth in CENTRIC and ECCENTRIC positions
Stability: Balanced articulation and occlusal contacts? (3)
- There must be 3 contact points in every mandibular contacting position: 1 anterior and 2 posterior - both at working and non working sides -protrusive movement: must be contacts in anterior, posterior and middle areas of dental arch
1?
- Frenulum labii superioris.
2?
- Vestibule sulcus.
3?
- Buccal frena.
13?
- Palatine rugae.
12?
- Incisal papilla.
11?
- Palatine raphe.
10?
- Palatal foveae.
9?
- Border between hard and soft palate.
8?
- Pterygomaxillary (hamular) notch.
7?
- Maxillar tuberosity.
6?
- Alveolar ridge.
5?
- Coronoid process area.
4?
- Vestibule.
12?
- Lingual frenulum.
11?
- Sublingual caruncle.
7?
- Pterygomandibular ligament.
7?
- Pterygomandibular ligament.
6?
- Retromolar trigone.
5?
- Alveolar ridge.
3?
- Buccal frena.
2?
- Vestibular sulcus.
1?
- Frenulum labii inferioris.
