SALIVA IMPLICATIONS IN PROSTHODONTICS - PowerPoint PPT Presentation

1 / 84
About This Presentation
Title:

SALIVA IMPLICATIONS IN PROSTHODONTICS

Description:

SALIVA IMPLICATIONS IN PROSTHODONTICS www.rxdentistry.net www.rxdentistry.net SIALORRHEA Excessive salivation often experienced by the individual and experienced by ... – PowerPoint PPT presentation

Number of Views:678
Avg rating:3.0/5.0
Slides: 85
Provided by: Prin242
Category:

less

Transcript and Presenter's Notes

Title: SALIVA IMPLICATIONS IN PROSTHODONTICS


1
SALIVA IMPLICATIONS IN PROSTHODONTICS
2
  • 1.Introduction
  • 2.Source composition Properties.
  • 3.Functions.
  • 4.Anatomy Histology of Salivary Glands.
  • 5.Control of salivation.
  • 6.Salivary flow rate.
  • 7.Salivary flow and ageing.
  • 8.Mastication, Oesophageal Function Saliva
  • 9.Xerostomia and its management.
  • 10.Sialorrhea.
  • 11.Prosthodontic considerations.
  • 12.Saliva as a diagnostic tool.
  • 13.Conclusion.
  • 14.Bibliography.

3
INTRODUCTION
  • Saliva is largely an unheralded ,unsung and
    ignored secretion.
  • Is saliva important? Theres an old axiom
    which states you never miss the water till the
    well runs dry. How true this is, especially for
    saliva. The fact is, a world without saliva is a
    world without pleasure.like living with a
    drought..
  • Saliva is most valuable oral fluid that is
    often taken for granted. It is critical for the
    preservation and maintenance of oral health, yet
    it receives little attention until quality or
    quantity is diminished. Consequently it is
    necessary for clinicians to have a good knowledge
    base concerning the norm of salivary flow and
    function

4
SOURCE
  • Saliva is a clear and slightly alkaline
    mucoserous exocrine secretion. It is a complex
    mixture of fluids, with contributions from major
    salivary glands ,parotid submandibular and
    sublingual, the minor or accessory glands and the
    gingival crevicular fluid. Additionally, it
    contains a high population of bacteria normally
    resident in the mouth , desquamated epithelial
    cells , and transient residues of food or drink
    following their Ingestion.

5
  • When referring to the fluid normally present
    in the mouth the term whole saliva is commonly
    used, as distinct from duct saliva which is
    that flowing from the individual glands.
  • Secretions enter into the oral cavity by way
    of
  • Parotid stensens duct- orifice in the cheek
    above the molar teeth.

6
  • Submandibular gland-whartons duct-sublingual
    caruncle situated to the lingual side of the
    mandible in the submandibular fossa.
  • Sublingual gland- Bartholins duct- empties
    along the sublingual fold in the floor of the
    mouth.
  • Accessory salivary glands empty through
    individual ducts at their respective locations.

7
COMPOSITION
  • 99.5water and balance made of solid substances-
    inorganic 0.2,organic 0.3.
  • The concentration of which are characterized by
    wide variation , both between individuals and
    with a single individual.
  • Organic constituents
  • Protein
  • 200mg/100ml(only 3 of the protein concentration
    in plasma)
  • Enzymes ,immunoglobulins, mucous glycoprotiens ,
    traces of albumin , poly peptides etc.

8
  • Alpha amylase
  • Major digestive enzyme.
  • Parotid-60to120mg/100ml.
  • Submandibular-25mg/100ml.
  • Hydrolysis of alpha 14 glycoside bond- end
    product is maltose.
  • Immunoglobulins
  • Secretary IgA- predominant-20 mg /100ml
  • IgG-1.5mg/100ML
  • IgM-0.2mg/100ml,arising from gingival crevice.

9
Antibacterial Proteins
  • Lysozyme-attacks components of the cell wall of
    certain bacteria leading to lysis.
  • Lactoferrin-iron binding protein- removes free
    iron from saliva depleting the supply of iron
    needed for bacterial growth.
  • Sialoperoxidase- oxidizes salivary thiocyanate
    ion to hypothiocyanate- potent antibacterial
    substance using hydrogen peroxide produced by
    oral bacteria as an oxidant.

10
Glycoprotiens
  • MG1 and MG2- submandibular and sublingual saliva
    a group of Proline rich glycoprotiens
    (PRPs)-parotid saliva
  • Other poly peptides
  • Statherin- rich in tyrosine and proline- inhibits
    the hydroxyapatite crystal growth- inhibitor of
    calculus formation both in glands and on the
    teeth.
  • Sialin- helps to regulate the Ph of plaque.

11
Other Organic Compounds
  • Many free amino acids are present at low
    concentration.
  • While saliva can be used by some oral
    bacteria as a sole source of nutrient ,the amino
    acid content is too low to provide a rich growth
    medium.
  • Urea - hydrolyzed by many bacteria with release
    of ammonia increase in pH.
  • Glucose- 0.5mg/100ml- are too low to support
    extensive growth, but may be raised in diabetics.

12
Inorganic constituents of whole saliva(mg/100ml)
13
  • Major ions main contributors to the osmolarity
    of saliva.
  • Bicarbonate principal buffer in saliva.
  • Fluoride- anticaries action.
  • Calcium and phosphate in saliva
  • Saliva is super saturated w.r.t hydroxyapatite
    at normal intraoral Ph, submandibular saliva to a
    greater extent than parotid saliva.
  • CA10(PO4)6(OH)2 10 CA2 6PO43- 20H-
  • ph Decreases- Dissolution
  • pH Increases- Rimenarilisation

14
PROPERTIES pH
  • 6.7 TO 7.4 - whole saliva
  • 6.0-7.8 - parotid saliva varies over a greater
    range
  • Depends on the bicarbonate concentration-
    concentration of which increase with increase in
    salivary flow.
  • Initially saliva is isotonic as is formed in
    the acini but it becomes hypotonic as it travels
    through the duct network .Hypo tonicity of
    unstimulated saliva allows the taste buds to
    perceive different taste and during low flow
    periods allows for expansion and hydration of
    mucin glycoprotiens which protectively blanket
    the tissues of the mouth.

15
  • Lower levels of glucose ,bicarbonate and urea
    in unstimulated saliva augment the hypotonic
    environment to enhance taste.
  • Viscosity
  • Viscosity of saliva is non newtonian. It
    exhibits different viscosities at different
    rates of shear , and has visco elastic
    properties.
  • Viscous behaviour changes with time after
    secretion because of its non newtonian
    properties and post-secretory degradation of
    mucous glycoprotiens by bacterial enzymes.

16
Volume
  • Mean daily salivary output -500ml-1500ml.
  • Average volume of saliva present in the oral
    cavity is approximately 1 ml. Contribution to
    the Total unstimulated volume of saliva-
  • Parotid-20
  • Submandibular -60
  • Sublingual-5

17
Factors influencing the composition of saliva
  • Flow rate
  • Increased flow rate-increase concentration of
    proteins, sodium chloride and bicarbonate,
    decreased phosphate magnesium.
  • Differential gland contributions
  • In unstimulated whole saliva parotid glands
    contribute only 20 of fluid volume whereas in
    stimulated saliva they become predominant. Thus
    the composition of the mixed fluid reaches that
    of parotid saliva at high flow rates.

18
  • Duration of stimulus
  • At a constant rate of flow the composition may
    vary with the duration of stimulation.
  • Nature of stimulus
  • Not biologically significant though salt
    stimulates- increase in protein content ,
    sugar- increase amylase content.

19
FUNCTIONS
  • Digestion
  • Salivary amylase initiates digestion of starch-
    inactivated in stomach- low ph and proteolytic
    activity.
  • Starch digestion in the mouth may be either
    beneficial in aiding starch clearance, or
    detrimental in liberating maltose for
    fermentation by oral bacteria to form acid-
    overall effect on caries is still undecided.
  • Lubrication
  • Aids in speech, mastication, swallowing and for
    general oral health and comfort- property water
    mucous gylcoproteins.

20
  • Glycoprotiens- high minor sublingual
    secretions,
  • Intermediate submandibular low in parotid
    saliva.
  • Dilution and clearance
  • Effect of water content of saliva is the dilution
    of substances into the mouth and their subsequent
    removal by swallowing or spitting.
  • Clearance is more rapid in some parts of the
    mouth than others. Unstimulated saliva is
    present as a thin film covering the hard and
    soft tissues of the mouth the velocity with
    which this film moves over the surface determines
    the rate of clearance of a substance from
    different sites,rapid clearance eg lower
    anteriors and upper posterior teeth.

21
  • Neutralisation and Buffering
  • Saliva is alkaline and is an effective
    buffer system.
  • Reduces the drop in plaque ph- cariogenic
    potential of foods.
  • Saturation
  • Saliva is supersaturated w.r.t tooth mineral-
    responsible for growth of hydroxyapatite crystals
    during the remineralisation phase of the caries
    process.
  • Inhibitors of precipitation- statherin
    proline prevents the excessive calcification in
    the mouth, however they cannot penetrate the
    plaque due to large molecular size - unable to
    prevent seeding and calculus formation.

22
  • Bacterial competition
  • Saliva plays a role in the control of the
    bacterial flora by acting as a selective growth
    medium.
  • Antibacterial effects
  • Pellicle and plaque formation

23
CONTROL OF SALIVATION
  • The salivary glands are unusual among the glands
    of the digestive tract in being under purely
    nervous control. Hormonal influences can alter
    the composition of saliva but are not responsible
    for its secretion.
  • Salivary glands are strongly stimulated by the
    parasympathetic nervous system, the sympathetic
    system has little or no direct effect on
    salivation. The indirect effect , a reduction in
    the rate of secretion from sympathetic
    stimulation is a result of vasoconstriction of
    blood vessels to the gland.

24
  • Stimulation of submaxillary sublingual glands
    is by superior salivary nuclei. Parotid
    inferior salivary nuclei.
  • parasympathetic fibres from-
  • 7th nerve - submandibular 9th
    nerve-parotid- are secretomotor and vasodilator.

25
ANATOMY AND HISTOLOGY OF THE SALIVARY GLANDS
CLASSIFICATION OF SALIVARY GLANDS
  • According to the size
  • Major-3pairs
  • Parotid
  • Submandibular
  • Sublingual
  • Minor-400 TO 500 .- Glossopalatine, Buccal ,
    Mucous glands of the cheek etc , spread in the
    oral cavity except at the gingiva and anterior
    part of the hard palate.

26
  • According to the location
  • Glands whose duct open in the vestibule
  • Lip superior labial and inferior
    labial
  • Cheek parotid and buccal.
  • Glands whose duct open in the oral cavity proper
  • Floor of the mouth submandibular,
    sublingual,
  • glossopalatine.
  • Tongue Body anterior lingual (of blandin
    nuhn)
  • Base posterior lingual, von
    ebner.
  • Palate- palatine.

27
  • According to the type of salivary secretion and
    duct opening
  • a serous secretion (thin watery) containing the
    enzyme ptyalin for the digestion of starchy
    foods.
  • a mucous secretion (viscid sticky or adhering)
    for lubrication.

28
  • serous- parotid , von ebner.
  • mucous- palatine, posterior lingual
  • mixed- predominantly serous - submandibular
  • mixed- predominantly mucous-sublingual

  • blandin nuhn,

  • buccal labial

29
  • Location of salivary glands

30
  • Parotid
  • superficial portion- in front of the
    external ear deeper part fills the
    retromandibular fossa.
  • Submandibular
  • In the submandibular triangle behind and
    below the free border of the mylohyoid muscle
    with a small extension lying above mylohyoid.
  • Sublingual
  • Between the floor of the mouth and the
    mylohyoid muscle- one main gland and several
    smaller glands.
  • Labial and buccal glands
  • Lips and cheek, although buccal glands are
    not examined by electron microscopy they are
    usually described as continuation of the labial
    glands.

31
  • Glossopalatine-
  • principally localized in the region of isthmus
    in glossopalatine fold.
  • Palatine glands-
  • aggregates in the lamina propria of the
    posterolateral region of the hard palate and in
    the submucosa of the soft palate and the uvula.
  • Lingual
  • anteriorlingual -apex of the tongue
  • Posterior Lingual (mucous)
  • lateral and posterior to the vallate papilla
  • Posterior lingual( serous)
  • between the muscle fibers of the tongue below
    the valate papilla.

32
(No Transcript)
33
  • Main features of parenchymal cells of salivary
    glands

34
  • Functions of ducts
  • The main function of salivary gland ducts is to,
    convey the primary saliva secreted by the
    terminal secretory units to the oral cavity. They
    are not just passive conduits also they actively
    modify the primary saliva by secretion and
    reabsorption.
  • Essentially all of the water enters saliva at the
    level of terminal secretory units, the striated
    and excretory ducts appear to be relatively
    impermeable to water

35
SALIVARY FLOW RATE
  • Flow rate volume (milli litres) of saliva
  • minute
  • there is great variability in individual
    salivary flow rate. The accepted range of normal
    flow ml/min is as follows

36
  • Methods of measurement of flow rate
  • techniques for assessing salivation salivary
    secretion rate has been reviewed and evaluated by
    many authors.
  • Accurate measures of salivary flow rate are
    required for a variety of clinical and
    experimental situations.

37
  • Two methods- a.measurement of whole saliva
  • b.measurement of
    parotid saliva..
  • Techniques for measurement of whole saliva
    unstimulated (resting)
  • Draining method
  • Spitting method
  • Suction method
  • Swab method

38
Techniques for collection stimulated whole saliva
  • Masticatory method (standardized piece of
    paraffin used)
  • Gustatory method(1 to 6 citric acid used )
  • The spitting method for estimating resting flow
    and masticatory method with paraffin chewing for
    stimulating saliva for measuring flow rates are
    reliable.

39
SALIVARY FLOW AND AGEING
  • Flow rate of unstimulated (resting )whole saliva
    with age
  • Since 70 of whole resting saliva comes from
    submandibular and sublingual glands , the
    decrease in its flow with age must largely be
    due to decrease in production.
  • Histological findings demonstrate that there is
    20 to 30 decrease in volume of salivary acini
    with age.
  • On the other hand numerous functional studies
    have failed to show any age related decrease in
    the flow of parotid saliva as the normal resting
    flow rates of parotid saliva are extremely small
    0.04 to 0.06 ml/min .Therefore often no saliva
    can be obtained and the frequency of not
    obtaining it increases with age .

40
  • Flow rate of stimulated whole saliva
  • The relationship SFR and ageing- of whole
    saliva is mixed. Most studies show no change or
    only a modest decrease in flow rate even though
    the histological findings show a significant
    decline in the volume of salivary acini. The fact
    that this acinar reduction does not affect the
    stimulated flow rate of saliva should not be
    surprising- most organs when stimulated,
    compensate for the loss of parenchyma.
  • Other factors influencing salivary flow rate
  • Diurnal variation, drugs, source of saliva, diet,
    duration and type of stimuli, hormones

41
MASTICATION ,OESOPHAGEAL FUNCTION AND SALIVA
Decreased mastication and saliva
  • Mastication is the exercise of the oral
    apparatus. Chewing increases ,function and lack
    of chewing induces atrophy of disuse. Indeed
    impaired mastication is associated with a
    reduction in the mass of salivary gland and a
    decrease in the synthesis secretion of saliva.
  • Findings indicate that the partial or total
    loss of teeth, the presence of dentures , the
    decrease in bite force, TMJ dysfunction ,
    extensive caries , pdl disease , pain ,
    immobilization of jaws and other clinical
    conditions contribute to in flow of saliva and
    salivary gland hypofunction.
  • Implicit in these findings is that dentists
    should place a high priority in restoration of
    masticatory function.

42
  • Increased mastication and saliva
  • Chewing induces an increase in the flow of
    stimulated whole saliva.
  • This facilitates taste, swallowing and
    alimentation, enhances clearance, buffers harmful
    oral and oesophageal acids and aids in the
    remineralisation of teeth .
  • Given the beneficial effects of stimulated saliva
    it is not surprising that considerable attention
    is given to agents which stimulate saliva eg
    chewing of paraffin wax ,sugarless chewing gum
    can increase flow, diminish the fall in plaque pH
    accumulation of harmful acids. Clinical trials
    have therefore shown that chewing sugarless gums
    reduces incidence of dental caries .

43
  • Saliva and oesophageal function
  • The reflux of gastric acid and food into the
    lower oesophagus-gastro oesophageal reflux (GERD)
    is a common condition that is associated with
    heart burn and nausea.
  • The clearance of acids from the oesophagus, like
    that of the mouth is a two stage process and
    saliva plays a significant role in it. Influx of
    saliva Vmax induces swallowing- initiates first
    phase of oesophageal clearance (primary
    peristalsis) This is manifested as a peristaltic
    wave which clears 90-95 of refluxed acid. A
    small amount of acid 5 remains, which is diluted
    and buffered by successive swallows of stimulated
    saliva .
  • Therefore patients with xerostomia, sjogrens
    syndrome and rheumatoid arthritis- advised to
    take chewing gum and sugarless candies and
    cholinergic agonist like pilocarpine.

44
  • Clearance , residual saliva and oral dryness
  • The mouth is a receptacle into which , for
    about 14 hrs of the day ,there is an influx,
    distribution and efflux of about 350 ml of
    resting saliva, additionally about 2hrs of the
    day variety of solids and liquids and about 250ml
    of stimulated saliva , enter or placed in the
    oral cavity. The process whereby substances are
    removed is known as salivary clearance. Central
    to this process are the act of swallowing and the
    flow of saliva.

45
  • Following deglutition there is progressive influx
    of unstimulated saliva. This is distributed
    throughout the mouth, where it mixes with and
    dilutes it contents, and coats the oral mucous
    membrane. As the volume of saliva increase it
    soon reaches a maximum volume, at which point
    another swallow occurs and the process starts
    all over again.
  • A small amount of saliva , as well as the
    substances contained within it remain in the
    mouth. This is referred to as residual saliva-it
    sticks as a thin film to the mucous membrane and
    surfaces of the teeth and flows into the
    interstices between teeth.

46
  • Some of the substances dissolved in this residual
    saliva, enzymes antibacterial peptides,
    antibodies, are protective to the oral cavity.
    Others like sugar and carbohydrates are
    potentially harmful.
  • The clearance process is described as similar to
    tidal exchange where following the ebb tide,
    there remains tidal pools and the ecosystem
    contained within them. Whichever analogy is used
    ,it should be clear that, with exception of
    substances wanted to be retained in the
    mouth-fluoride and chlorhexidine, fast clearance
    favors health and slow rates favors disease.

47
  • The volume of residual saliva was largely
    dependent on the max volume V max before
    swallowing- mean value 1.07ml and the resting
    flow rate of whole saliva.The mean volume of
    residual saliva -0.77ml.
  • Average thickness of the residual saliva film on
    oral tissues Vmax
  • total surface area of
    the oral tissues.
  • 0.036to 0.05mm.
  • Because of the variation in the distribution of
    saliva the shape of the teeth and their
    disposition in the maxilla or the mandible the
    thickness of the film varies.

48
  • Palate and the upper lip were the driest and
    covered with least amount of saliva floor of the
    mouth and dorsum of the tongue were wettest.
  • Dryness is alleged ,is dependent on the volume of
    saliva present on the oral mucous membrane and
    the rate of its evaporation from them. Hard
    palate fewer glands, far away from the orifices
    of major glands and is the area of high
    evaporation.
  • it is proposed that the thickness of the film of
    residual saliva on the hard palate is a valid
    indicator of the degree of oral wetness and
    xerostomia.

49
XEROSTOMIA
  • It is a subjective sensation of a dry mouth,
    frequently but not always associated with
    salivary gland hypofunction.
  • Dryness of mouth is one of the oldest symptoms
    recorded by man.
  • Ancient records describe the use of rice tests to
    determine guilt or innocence if
    innocent-ingestion of rice will stimulate the
    flow of saliva, if guilty mouth will be dry and
    swallowing difficult or even impossible.

50
  • PREVALANCE

51
  • HOW DOES THE SENSATION OF ORAL DRYNESS CORRELATE
    WITH THE FLOW OF SALIVA?
  • Fox et al. Concluded that oral dryness was not
    a valid indicator of salivary hypofunction.
  • Sreebny validini also showed that dry mouth per
    se was not a valid indicator of salivary
    hypofunction.Their findings slightly more than
    half (54)of the subjects who complained of
    xerostomia had resting whole saliva flow rates
    abnormally low (0.1ml/min)
  • Xerostomia is rarely a solitary symptom.
    Accompanying it is a wide variety of other oral
    and non oral complaints.

52
CAUSES OF XEROSTOMIA
53
  • Overall the most common cause of decreased
    salivary output is the intake of drugs.
  • A wide variety of medications referred to as
    Xerogenic drugs induce oral dryness.
  • Prevalence of xerostomia is not only related to
    drugs that are xerogenic but to the total number
    of drugs taken. As a general rule the drying and
    hyposalivatory effects of drugs are transient.
  • Anticholinergic, antidepressants ,
    antihistamines, antipsycotic, antihypertensives,
    sedatives, diuretics and analgesics.

54
  • Diagnosis of xerostomia
  • Clinically
  • Medical history, H/o radiation chemotherapy, oral
    infections, questionnaire.
  • Dentists should provide the patients with a dry
    mouth questionnaire-
  • Do you sip liquids to aid the swallowing of
    foods?
  • Does your mouth feel dry when eating?
  • Do you have difficulties swallowing any foods?
  • Does your mouth usually become dry when you
    speak?
  • Lab tests flow rate tests , sialometry ,etc.

55
  • MANAGEMENT
  • Reassurance, symptomatic and supportive care.
  • Patient education- to compensate for the oral
    dryness patient may stop chewing prefer a
    liquid or a semisolid diet rich in fermentable
    carbohydrates.
  • Because decreased mastication worsens the
    condition , patients should undergo nutritional
    counseling to limit the harmful effects of
    reactionary diet modifications.

56
  • Patient should be reminded to chew , as
    periodontal mechanoreceptors mechanical
    stimulation of the tongue oral mucosa are vital
    stimuli for salivation. Sugar free candies
    chewing gum are recommended .
  • Use of medication before bed time should be
    discouraged as this time of the day coincides
    with lowest salivary flow rate.
  • Should sip cool water throughout the day and
    drink milk with their meals.

57
  • Water is a poor mucosal wetting agent, lacks
    buffering capacity, lubricating mucins. Whole
    milk may serve as a better substitute. Citrus
    fruits, caffeine and alcohol, alcohol containing
    mouth washes cause dehydration must be avoided.
  • sleep on the side to reduce mouth breathing,
  • Apply petrolatum based lubricants to lips during
    the day bedtime
  • Cool air humidifier be placed in the room.
  • Medication -capable of stimulating salivary
    glands- pilocarpine -5 to 10 mg ,3 or 4 times
    daily, 30 min before meals administered.

58
  • ARTIFICIAL SALIVA SUBSTITUTES
  • Commercially available products contain
  • Carboxy methylcellulose lubrication,
  • Animal mucins to increase viscosity,
  • Parabens- inhibit bacterial growth,
  • Sugar free agents- xylitol, sorbitol- sweetners,
    mineral salts- simulate electrolyte content,
  • Flouride- reminaralisation.
  • Trade names salivart(spray), mouthkote (spray),
    oral balance (gel).
  • The oral mucous and the intaglio surface of
    prosthesis can be sprayed throughout the day with
    artificial saliva .

59
  • Electrical stimulation- SALITRON-.battery
    operated devices which deliver an electrical
    stimulus to the tongue and palate for saliva
    production.
  • Acupuncture.
  • Future aspects
  • gene therapy
  • tissue engineering.

60
  • Therapeutic irradiation of the head and neck
  • Xerostomia and salivary gland hypofunction are
    almost inevitably seen in patients whose salivary
    glands are irradiated for head and neck cancer.
  • Sensation of oral dryness occurs early in the
    course of radiation. It has been shown that 24
    hrs after administration of only 2.25 Gy(225Rads)
    there is already a 50 decrease in flow of the
    parotid saliva.
  • When exposure exceeds 50Gy (5000Rads) the
    reduction in flow is profound for the most part
    permanent , the decrease amounts to gt90.
  • Parotid glands are the most sensitive to ionising
    radiation the other glands in the decreasing
    order of sensitivity- submandibular, sublingual
    and the minor glands.

61
  • In Preventive therapy maintain impeccable oral
    hygiene,
  • schedule frequent recalls , use topical flouride
    regime.
  • Prosthodontic management
  • Thorough case history
  • Elastomeric impression materials preferred.
  • In the partially and fully edentulous patient,
    susceptibility to mucosal ulcerations fungal
    infections- patient should be made aware of the
    well fitting denture minimize denture use at
    times when salivary flow is noted.
  • Patient should be made aware of a well fitting
    denture and minimize denture use at times when
    decreaesed salivary flow is noted.

62
  • Artificial saliva reservoir
  • Fabrication of intra oral reservoirs
  • Construct the maxillary denture with an accepted
    technique. provide the maximum inter arch space
    possible with an acceptable vertical dimension of
    occlusion.
  • thicken the external palatal surface of the
    trial denture with wax.
  • soften the wax and contour its surface with
    functional movements of the tongue (swallowing,
    speech , mastication).
  • Complete the wax up, ,invest it , and boil out
    the wax.

63
  • Construct a chrome cobalt palatal plate on a
    duplicate cast cover the palate to the palatal
    portion of the alveolar process beginning of
    the post palatal seal. Post palatal seal not
    included in the metal to decrease the weight of
    the denture to prevent premature loss of the
    artificial saliva due to leakage between metal
    and acrylic resin parts of the denture. The metal
    palate is 0.45mm thick at the center 1mm thick
    where it joins the acrylic base.
  • Drill two filling holes 1.5mm in the metal base
    one anterior and one posterior to the midline.
  • Glue the metal base to the flasked cast.
  • Fill the maximum space available for the
    reservoir with optosil which is then glued to the
    metal base .

64
  • space for acrylic resin must remain between the
    filler and the investment
  • Pack and cure the acrylic resins into the flask
    in the usual manner.
  • Remove the metal base and the filler from the
    denture and reattach the metal base into the
    denture. The border of the metal base interlocks
    with the acrylic resins internal surface of the
    palate .
  • Drill a saliva release hole (0.1 to 0.2) in the
    reservoir at the midline of the denture 5mm
    palatal to the anterior teeth.

65
(No Transcript)
66
(No Transcript)
67
SIALORRHEA
  • Excessive salivation often experienced by the
    individual
  • and experienced by the individual noticed
    by the operator.
  • Prosthodontic management
  • Impression making mouth irrigated with an
    astringent.
  • Mouth washed prior to investing impression
    material.
  • Fast setting impression material is used.
  • Anti sialagogues administered 1to 2 days before
    treatment
  • Dummy dentures are fabricated given.

68
Prosthodontic Considerations
  • From the prosthodontists point of view, salivary
    glands are of great importance both anatomically
    and physiologically.
  • Extension of denture base
  • Stensens duct- it is rare for a maxillary denture
    to cause obstruction to this duct.
  • whartons duct-extension of the lingual flange in
    this region can lead to obstruction patient
    complains of swelling under the tongue while
    eating.
  • Sublingual- it is rare for a denture to cause any
    significant obstruction.

69
  • Amount of saliva
  • Will effect the denture construction process
    quality of the final product.
  • If a mouth is dry . Retention of the denture
    affected increased potential for soreness.
  • Excess saliva- complicates denture construction-
    impression making.
  • When new dentures are first inserted increased
    salivation due to temporary increase in salivary
    flow is a natural response to foreign object in
    time will subside. Patients need assurance about
    this.
  • Deglutition will be necessary to evacuate the
    excess - advised not to rinse and spit as this
    unsettling of the denture bases.

70
  • Consistency
  • Best to work with a serous type of saliva.
  • Presence of thick saliva may create a problem for
    maxillary complete denture retention,-create
    hydrostatic pressure in the area anterior to the
    post palatal seal area- downward dislodging force
    exerted upon the denture base.
  • In an effort to alleviate this problem, a cupids
    bow can be scribed on the master cast .
  • Watt and macgregor feel that extension of the
    posterior palatal seal line will contain the
    thick mucous in the posterior part of the denture
    to provide a seal even if the posterior portion
    of the denture base is slightly out of contact
    with the palatal tissues.

71
  • Thick saliva also complicates impression making
    by forming voids in the impression surface while
    the impression sets- palatal surface should be
    wiped free of saliva the mucous glands massaged
    with a piece of gauze just before the final
    impression is made to eliminate as much as mucous
    as possible.
  • It may also be factor for the patient to gag
    while impressions are made and after the
    placement of new dentures.

72
Role of saliva in denture retention
  • Saliva is considered as a major factor in
    evaluating the physical influences that
    contribute to the denture retention .
  • The physical forces in which saliva is involved
    are
  • Adhesion
  • cohesion
  • atmospheric pressure
  • capillary attraction
  • peripheral seal
  • Viscosity of saliva Surface tension.

73
  • Adhesion
  • Adhesion is the physical attraction of unlike
    molecules for each other.
  • It acts when saliva sticks and wets to the basal
    surface of the dentures at the same time to the
    mucous membrane of the basal seat. A watery
    saliva is quite effective , provided the denture
    base material can be wetted.
  • Saliva that is thick ropy adheres well to both
    the denture base and the mucosa but since much
    of it is produced by the palatal glands under the
    maxillary denture base it builds up pushes the
    denture out of position. The forces of adhesion
    still act on them but the hydraulic pressure
    produced by the thick mucus secretion over power
    them.
  • The amount of retention provided by adhesion is
    directly proportional to the area covered by the
    denture

74
  • Cohesion
  • Retentive force as it occurs in the layer of
    saliva between the denture base the mucosa.
    Since saliva is a liquid the layer should be thin
    if it is to be effective.
  • Interfacial surface tension
  • Is the resistance to separation possessed by the
    film of liquid between two well adapted surfaces.
    It again found in the thin film of saliva
    similar in its action to cohesion and to
    capillary attraction.

75
  • Capillary Attraction
  • Is a force that causes the surface of a liquid
    to become elevated or depressed when it is in
    contact with a solid.
  • Peripheral Seal
  • Developed with the proper extension of the
    denture into the vestibule.
  • Denture border merging against the mucosal border
    assembled by a thin film of saliva provides
    border seal as it prevents ingress of air , thus
    enabling the denture to be in their position.

76
  • VISCOSITY OF SALIVA
  • Analogies are usually drawn between the clinical
    situation the two circular parallel plates
    separated by the liquid. Under these conditions
    Stephens law can be applied

77
(No Transcript)
78
  • Relationship expressed in equation 2 shows that
    the force required to displace a denture is
    proportional to the viscosity of saliva fluid
    film the square of area of the denture
    inversely proportional to the square of the
    distance separating denture from the supporting
    tissues the time of force application .
  • Degree of retention possessed by the denture
    depends critically on the area of its
  • fitting surface hence the requirement to
    extend the denture base to the maximum allowed
    by the muscle insertion.
  • degree of closeness of fit.
  • Viscosity of the saliva
  • The glycoprotiens the proteoglycans
    dissolved in the saliva not only increase the
    viscosity but provide it with

79
  • pseudo plastic properties. When low shear
    stress is encountered in the mouth when
    mastication is not taking place , saliva acts as
    a semisolid.
  • equation 1. and 2. are valid if we assume that
    the circular parallel plates are completely
    immersed in the liquid. In mouth the dentures are
    not immersed all the time , hence a meniscus can
    form at the periphery and surface tension can be
    included as a factor.
  • Laplace formula

80
  • Any positive effect that surface tension has must
    depend on their being an intact saliva/air
    interface at the periphery of the denture, a
    condition which could exist only during speech.
    When eating and drinking the integrity of any
    peripheral saliva/air interface would be
    destroyed and the effect of surface tension
    becomes negligible.Therefore emphasis is placed
    on close fit and accurate impression technique

81
SALIVA AS A DIAGNOSTIC TOOL
  • Saliva is not widely used as a indicator of
    health . disease. However salivary testing is
    becoming more common as clinicians have begun to
    appreciate its advantages investigators defined
    its worth.
  • Salivary levels of drugs detected following
    therapeutic medications.
  • Saliva drug testing kits are commercially
    available. Included in these are the tests for
    alcohol, cocaine HLA typing, HIV1 ,HIV2 ,DNA,
    etc
  • Salivary cortisol is an indicator of hypothalamic
    pituitary

82
  • adrenal axis function- used to quantify the
    human stress to determine the effect of
    treatment on it.
  • to detect antibodies-hepatitis A, rubella virus,
    etc
  • to diagnose systemic disease after salivary gland
    dysfunction- sjogrens syndrome, alzheimers
    disease, cystic fibrosis,etc.
  • Forensic odontology
  • Salivary pH assessment using telemetry
  • Device called telemetry system is
    incorporated in the denture which has a
    radiosensitive diode, oscillator, ph sensor, and
    a computer analyzer.

83
CONCLUSION
  • The multi factorial role of salivary components
    continue to represent a focused area of dental
    research.
  • The knowledge of normal salivary composition,
    flow function is extremely important on a daily
    basis when treating patients.
  • Dental health professionals spend untold hours
    removing this precious natural resource to
    perform therapy, with little regard to its value
    until flow is significantly reduced.
  • Whether saliva occurs in quantities large or
    small , recognition should be given to the many
    contributions it makes to the preservation
    maintenance of oral systemic health.

84
(No Transcript)
Write a Comment
User Comments (0)
About PowerShow.com