oral function Flashcards
4 correlating stages in the feeding sequence (before swallowing).
- ingestion - biting
- stage one transport - moving material from the front to the level of the posterior teeth
- mechanical processing - broken down and mixed with saliva
- stage two transport - bolus moved back
Function of facial muscles in feeding
facial muscles help to control food bolus and prevent spillage:
-orbicularis oris
-buccinator
What considerations should be made regarding the tongue when setting posterior teeth in a RPD.
inaccurate placement of mandibular posterior teeth might interfere with tongue’s movements and will compromise retention and stability of the denture
Four mechanisms which prevent reflux during swallowing.
elevation of the soft palate
sides of the tongue contacts pillars of faces
dorsum of the tongue contacts posterior pharyngeal wall
upper oesophageal sphincter = reflux from oesophagus into pharynx
lower oesophageal sphincter = reflux from stomach into oesophagus
Muscles involved in food processing, list 4 main types?
muscles of mastication = temporalis, masseter, lateral and medial pterygoid
suprahyoid (digastric, stylohyoid, mylohyoid and geniohyoid muscles)
infrahyoid (sternohyoid, sternothyroid, thyrohyoid and omohyoid )
tongue muscles (intrinsic and extrinsic)
movements that occur during chewing process, list and describe?
Opening: The jaw opens to allow food to enter the mouth.
Closing: The jaw closes to grip and compress the food between the teeth.
Lateral movement: The jaw moves from side to side to grind the food between the molars.
Vertical movement: The jaw moves up and down to break down the food and mix it with saliva.
Tongue movement: The tongue helps to move food around the mouth and push it between the teeth for grinding.
Cheek movement: The cheeks help to keep food between the teeth during grinding.
Saliva production: Saliva is produced in the mouth to moisten the food and aid in digestion.
occlusal phase (mandible is stationary/teeth are joined)
opening phase (jaw depressor muscles are active)
closing phase (jaw elevator muscles are active)
what muscles are responsible for changing shape and position of tongue and name them?
intrinsic = alter shape only = longitudinal, vertical, transverse
extrinsic = alter shape and position =
genioglossus
hyoglossus
palatoglossus
styloglossus
What are the 4 muscles of mastication
temporalis
masseter
lateral and medial pterygoid
Mouth movement during mastication (2)
i. What is the diagram called
ii. What does it show
posselt’s envelope of motion
refers to the range of motion of the mandible
saggital view of maximum mandibular movement
What are the tmj jaw movements
rotation - initial opening
translation - wider opening
What are the intrinsic tongue muscles and there role
intrinsic muscles alter the shape of the tongue
longitudinal
vertical
transverse
What are the extrinsic tongue muscles and there role
alter shape and position within the oral cavity of the tongue
genioglossus
hyoglossus
palatoglossus
styloglossus
Physiological and psychological reason of keeping PDL for dentures
PDL acts as a shock absorber, distributing forces equally
PDL helps to maintain shape and density of alveolar bone
keeping the PDL can provide a sense of continuity and familiarity.
patients may also experience a psychological benefit from the tactile sensation of the PDL, which can help them feel more connected to their denture and improve their ability to chew and speak.
What are the muscles that control mandibular movement?
masseter = closing the jaw and elevation of the mandible
temporalis = closing the jaw and retraction of mandible
medial pterygoid = elevates the mandible
lateral pterygoid = protrusion, depression of mandible
Describe the movements of the Temporomandibular Joint (TMJ)
ROTATION = initial opening = hinge
TRANSLATION = wider opening = protrusive or retrusive
What are the intrinsic muscles of the tongue? What is their function?
alter shape of the tongue
longitudinal
vertical
transverse
A 65-year-old man was presented to you seeking replacement of his lower missing teeth. On examination, there were only two remaining over-erupted lower canines and an upper well-fitted complete denture.
- One of the treatment options you offered to the patient was to decoronate the abutments and keep the roots to cover them. What is this treatment option called?
the over denture
What are the physiological and psychological advantages of overdenture?
While the roots and their periodontal ligaments remain, PERIODONTAL MECHANORECEPTORS allow finer discrimination of food texture, tooth contacts and levels of functional loading.
A better an appreciation of food and a more PRESICE CONTROL OF MANDIBULAR MOVEMENTS than is provided by full dentures.
PSYCHOLOGICAL BENEFIT by preventing the feeling of total loss of natural teeth.. Makes eventual transition to conventional complete dentures more acceptable..
List the characteristics of periodontal mechanoreceptors. (8 marks)
Location: PERIODONTIUM (periodontal ligament, cementum, and alveolar bone)
Type: Ruffini endings, Golgi tendon organs, Pacinian corpuscles, and free nerve endings.
Sensitivity: HIGHLY sensitive to MECHANICAL stimuli, including pressure, tension, and vibration.
Adaptation: RAPID adaptation to sustained stimuli, meaning that they become less responsive over time to a constant stimulus.
Innervation: SENSORY FIBRES OF TRIGEMINAL which carries sensory information from the face and oral cavity to the brain.
Function: The primary function of periodontal mechanoreceptors is to provide SENSORY FEEDBACK about the position and movement of the teeth and jaws, which is essential for proper chewing and speaking.
Response to injury: Injury or damage to the periodontal tissues can result in changes in the activity of periodontal mechanoreceptors, leading to altered sensory feedback and potentially contributing to conditions such as tooth mobility or occlusal trauma.
Role in oral motor control: In addition to providing sensory feedback, periodontal mechanoreceptors may also play a role in ORAL MOTOR CONTROL
It is 9:00am and your first patient, who had a wisdom tooth surgically extracted under local anaesthetic a week ago, attends complaining that his lower lip is still numb. You examine the area and notice that the patient has been biting his lip and there is ulceration in the area. Can you provide an explanation for what had happened?
Lip paresthesia
* Numbness may have remained due to damage(pressure to nerve) of the mandibular division of the V
CN during anesthesia or the procedure
* Patient should be reminded to avoid biting lip and follow-up scheduled to evaluate paresthesia
* Prognosis is favourable as long as there is no complete section of the nerve
You plan to take impressions to prepare a new denture for your 10:00am patient. As you are selecting a suitable tray, you recall this patient is very prone to gagging every time you try to place an impression tray into his mouth. What mechanisms are involved in the gag response?
Acts to prevent material entering hypopharynx.
* Evoked by mechanical stimulation of fauces, palate, posterior tongue, pharynx.
Afferent (sensorial) response from glossopharyngeal nerve (IX). Efferent from various nerves (including but not limited to V,IX,X, XI and XII). The motor(secretory) visceral nerves of salivary glands are also stimulated. That elicits a complex efferent motor and secretory response
- An ‘oversensitive’ gag reflex is a clinical problem.
- Some patients gag when instruments and/or materials are placed in the mouth.
Your 11.0am patient arrives to tell you that she has a “stinking cold” and that her nose is “bunged up”. She complains that “she lost her taste”. Can you provide an explanation for her complaint?
Infection of the nasopharynx may be associated to loss of olfactory sense
Patients have difficulty to discern between taste and olfaction, thus interchanging the terms
What are the main factors which correlate with masticatory performance?
age, number of teeth, maximum bite force
Where are the greatest bite forces generated and why?
between 1st molars
position relative to TNJ and muscles (molars are nearer the force generating muscles and the tmj fulcrum)
root area (pal support)
What is the Shortened Dental Arch (SDA)?
20 teeth are considered minimum for acceptable
- masticatory function
- aesthetics
- maintenance of oral hygiene
What is the Shortened Dental Arch (SDA)?
20 teeth are considered minimum for acceptable
both incisors, canine, both premolars
SDA provides sufficient occlusal stability
SDA provides satisfactory comfort and appearance
List 2 factors which may contribute to the failure of a functional SDA
increased occlusal forces on remaining teeth
tmj disorders
What are the factors which may contribute to the reduction of biting forces in complete denture wearers?
biting load is carries by mucosa of residual ridge = which is not designed to bear masticatory loads
support area is reduced
Explain how the chewing motion of the jaws can be described in the same way as how a nutcracker works?
jaw joint is a hinge of the nutcracker
front teeth are ends of the handles
molars close to the hinge itself
if you place it too far from hinge, you have to use extra force to break it
name 3 stages of swallowing
- buccal phase (voluntary)
- pharyngeal stage (involuntary)
- oesophageal stage (involuntary)
which type of tissue covers the articular surface of the mandibular condyle?
fibrous tissue
what prevents aspiration of food particles into larynx and trachea during swallowing?
relaxation of inferior pharyngeal constrictor
