PRELIMS Flashcards
Represents a compromise in the integrity of the masticatory system
Edentulous state
The relationship between the biologic behavior of oral structures and a physical influence of a dental restoration
Biomechanics in dentistry or dental biomechanics
Clinical implications of the biomechanical differences can be considered under the FF:
- Modifications in area of support
- Functional and Parafunctional considerations
- Changes in morphologic face height
- Cosmetic changes
- Adaptive responses
Teeth are supported by the
Periodontium
What comprises the periodontium
Hard CT:
- Cementum
- Bone
- PDL
Soft CT
- Lamina propria of the Gingiva
Periodontium is attached to the dentin by ___ and to the jawbone by the __.
cementum, alveolar process
Two principal functions of periodontium
- Support
- Positional adjustment of the tooth
Maximal bite forces appear to be __ to __ than for persons with natural teeth
FIVE to SIX times less
Mean denture- bearing area for edentulous maxilla
22.96cm2
The study of human movement including interaction between participant and equipment
Biomechanics
biomechanics are broken down into two broad areas:
Kinetics, kinematics
Study of internal and external forces acting on the body
Kinematics
Study of movements of the body as a result of these forces
Kinematics
Dentulous Masticatory load maximum bite force during chewing
20 kilos
Edentulous masticatory load maximum bite force during chewing
6 to 8 kilos
Movement of denture bases in any direction on their basal seats can cause ___
Tissue damage
Mean denture- bearing area for edentulous mandible
12.25 cm2
Mean denture- bearing area for dentulous maxilla
45 cm2
Mean denture- bearing area for dentulous mandible
45 cm2
Consists of denture-bearing mucosa, submucosa and periosteum, and the underlying residual alveolar bone
Residual ridge
The foundation for dentures
Residual ridge
How is residual ridge formed?
Alveolar process made edentulous by loss of teeth ➠ alveoli are filled in with new bone ➠ becomes the residual ridge
Development and adaptation of the occlusion
- Developing dentition
- Healthy adult dentition
- Deteriorating adult dentition
- The edentulous state
- Extensive sensory input
- Development of motor skills and neuromuscular learning
- Dental, alveolar, craniofacial adaptability
Developing dentition
- Dental adaptation (wearing, drifting, extrusion)
- Bone adaptation is reparative
- Learned protective reflexes
Healthy adult dentition
- Partial edentulism
- Periodontal disease
- Diminished dental reflex adaptation
Deteriorating adult dentition
- Residual ridge reduction
- Compromised reflex adaptability
- Increase in parafunctional movements
The edentulous state
Morphologic changes associated with the edentulous state
- Deepening of the nasolabial groove
- Loss of labiodental angle
- Decrease in horizontal labial angle
- Narrowing of lips
- Increase in columella-philtral angle
- Prognathic appearance
Soft tissue changes
- Soft tissue hyperplasia
- Denture stomatitis
Result of a fibroepithelial response to complete denture wearing
Soft tissue hyperplasia
- It is often asymptomatic
- May be limited to the tissues around the borders of the dentures in the vestibular, lingual, or palatal regions or part of the residual ridge
Soft tissue hyperplasia
Etiology of soft tissue hyperplasia
- Changes in the alveolar sockets during extractions
- Trauma from denture wearing
- Gradual residual ridge resorption
- Changes in soft tissue profile and TMJ functions
- Changes in relative proportions of both jaws
- Habits and duration of wear
- Aberrant forces to which the supporting tissues are subjected
- Expressive forces on limited segments
Hyperplasia occurring around the border of a denture
Epulis fissuratum
Occurs in the free mucosa lining the sulcus or at the junction of the attached and free mucosa
Epulis fissuratum
Develops as a result of chronic irritation from ill-fitting or overextended dentures
Epulis fissuratum
Treatment of epulis fissuratum
Surgical excision only after a period f prescribed tissue rest to reduce edema
- Chronic inflammation of the denture-bearing mucosa
- Asymptomatic; may be localized or generalized
Denture stomatitis
Causes of denture stomatitis
- Nocturnal denture wear
- Trauma from ill-fitting dentures or parafunctional habit (predominant etiologic factor)
- Hypersensitivity to some component of the denture material with consequent allergic response
Treatment of denture stomatitis
- oral and denture hygiene accompanied by tissue rest
- Antifungal therapy
- Surgical excision of papillomatosis by electrosurgery or cryosurgery
- Sometimes painful inflammation of the corners of the mouth
- Attributed to a reduction of the vertical dimension of occlusion
Angular cheilitis
period of senescence
- Oral changes
- Mucosa and skin atrophy
- Physiologic changes
period of senescence (oral changes)
- Changes in the size of the basal seat
- Disuse atrophy
- Alterations in the sense of taste
- Dryness of mouth
- Reduction of masticatory activity
Mechanism of complete denture support
i. Masticatory loads
ii. Mucosa support
iii. Residual ridge
iv. Physiological effect on retention
Basic challenge in the treatment of edentulous patients:
Difference between the ways natural teeth and their artificial replacements are supported
Minimal tolerance of the denture-bearing area can be reduced further by the presence of __
Systemic diseases
Residual ridge consists of:
- Denture-bearing mucosa
- submucosa
- periosteum
- underlying resiudal aveolar bone
what to do to avoid residual ridge reduction
Dentist should preserve and protect any remaining teeth
Direction of bone resorption: maxilla
resorbs UPWARD and INWARD to become progressively smaller
Direction of bone resorption: mandible
Inclines OUTWARD, and becomes progressively wider
the changes in the edentulous and maxilla makes the patients appear ___.
Prognathic
Physical factors affecting retention of complete denture under the control of the dentist
- Maximal extension of the denture base
- Maximal intimate contact of the denture base and the basal seat
Muscular factors affecting retention of complete denture under the control of the dentist
- Buccinator muscle
- Orbicularis oris
Intrinsic and extrinsic muscles of tongue
if there is low salivary flow then there is ___
Low denture retention
Consists of a rhythmic separation and apposition of the jaws
Mastication
these muscles keep the food bolus between the occlusal surfaces of the teeth
Tongue and cheek muscles
importance of the placement of artificial teeth in making of complete dentures
teeth must be placed within the confines of a functional balance of the musculature involved in controlling food bolus between the occlusal surfaces of the teeth
Complete dentures important note
CD are poor substitutes for natural teeth. these serve as prosthesis for missing teeth
Any habitual use of the mouth not related to eating, drinking, or speaking
Parafunction habits (bruxism, tongue-thrusting, mouth breathing)
Common and frequent cause of soreness of the denture-bearing mucous membrane
bruxism
dentists may seek to minimize force distributioon by
- Maximize denture base coverage
- Occlusal surface of artificial teeth be made smaller
during swallowing or chewing, the amount of force generated by px masticatory system is __ by the dentists
not controlled
how to reduce occlusal load per unit area of mucosa
CD base extension within morphological and functional limits
terminal stage of skeletal growth is usually at what age
20-25 y.o but growth and remodeling of bony skeletoon continue well into adult life
reduction of residual ridges causes reduction in total face height resulting to
Mandibular prognathism
Position of the condylar head in the fossa and its relative position
Centric relation and centric occlusion
- most posterior position of the mandible
- most often, the teeth dont come together normally
Centric relation
centric relation position is dictated by the __
Condylar head/ fossa
- habitual position
- position of the condylar head can be ANYWHERE within the fossa
Centric occlusion
often dictated by habit and teeth that give the “right feel” feeling when you bite
Centric occlusion
most posterior position of the mandible relative to the maxilla at the established vertical dimension
Centric relation
- Coincides with a reproducible posterior hinge position of the mandible
- unconscious swallowing is carried out with the mandible at or near this position
Centric relation
Mandibular position anterior to centric relation where most functional natural tooth contacts occur
Centric occlusion
Impaired dental efficiency resulting from partial tooth loss and absence of, or incorrect, prosthodontic treatment
temporomandibular disorders (TMD)
Denture wearers suffer DJD more frequently than persons with complete natural dentitions
Degenerative Joint disease (DJD)
- it is a process rather than a disease
- may be age-related rather than due to the state of dentition
Degenerative joint disease (DJD)
individual behavioral and adaptive responses
- Cosmetic changes
- Dietary changes
- Adaptive and Physiological responses
- Adaptive potential of the patient
this determines the degree of success of clinical treatment
patient’s ability and willingness to accept and learn to use dentures
- it extends from the labial aspect of the residual ride to the lip
- no muscle fibers
Labial frenum
v-shaped notch to prevent interference with the frenum
Labial notch
Clinical significance of labial frenum and notch
has to be relieved in impressions to prevent dislodgement of denture and prevent uilceration
Categories in anatomy of denture bearing areas (Maxila)
- Limiting structures
- Supporting structures
- Relief areas
