Retentive Clasp
engages undercut below height of contour
(gingival 1/3 of crown within the undercut- SUPRAbuldge)
*NOT a base metal alloy
Reciprocal Clasp
passively touch above height of contour
(middle 1/3 of crown)
Requirement of major connector
Rigidity (support)
2 main purposes of MAJOR connector
Rigidity (support), stability
what does reciprocating arm of clasp do?
1. counteracts retentive clasp
2. stabilization
3. indirect retainer
function of a rest
prevent displacement (resist vertical tissue force) / support
purpose of indirect retainer
- prevents displacement of denture base
- on oposite side of fulcrum
most important in denture retention
peripheral seal
primary retention for max denture
(main stress bearing areas)
residual RIDGES / palate
secondary- rugae
primary retention for mand denture
(main stress bearing areas)
buccal shelf
secondary- anterior lingual border
best indicator for success of a denture
ridge
extends 1-2mm beyond vibrating line
max denture
covers 2/3 retromolar pad
mand denture
DB flange is determined by...
Masseter
most important in denture retention
peripheral seal
combination clasp
wrout wire (retentive) and cast wire (reciprocal) clasps
what connects the major connector w/ the rest seats
minnor connector
Class I and II - indirect retention?
yes
Class III and IV- indirect retention?
no
for bilateral distal extension use..
indirect retention (bc it is TISSUE supported)
post extension of PPS is...
2mm beyond vibrating line (fovea palatini)
3 things to determine PPS
1. throat form
2. tissue type
3. fovea location
PPS in max denture will compensate for
polymerization and cooling shrinkage
why place PPS?
compensates for shrinkage
excessive depth of PPS results in...
unseating of denture
if the palatal vault is too deep, what happens to vibrating line?
the vibrating line is more pronounced and forward (anterior)
the higher the palatal vault =
the more abrupt and forward the vibrating line
(gives a NARROWER PPS area)
when do you remove palatal tori?
when it prevents seating of the denture and formation of the posterior seal
removing palatal tori will do what for the future of the PPS?
increase seal
palatal tori should be removed when...
if posterior to vibrating line- interfere w/ PPS
major connector design for large inoperable palatal tori (extending to soft palate)?
horseshoe
reason for splint after palatal tori removal
helps prevent hematoma formation
hinge axis:
face-bow
what does the face bow do?
translates the relationship of the max to the terminal hinge axis using a 3rd point reference
purpose of the plaster index?
preserve facebow transfer (so you don't have to take it again)
reason for altered cast technique when doing a distal extension RPD?
(Kennedy I, II)
support
Sibilant Sound
allows max incisors to nearly touch mand incisors
Sibilant sound is altered w/....
altered VDO
Fricative sounds are made by...
allowing max incisors to nearly touch the slightly inverted lower lip
what can't the pt. say if the upper anterior teeth are too superior and forward for the denture?
F and V
what sound is used to evaluate VDO?
S
what will the S sound do when checking VDO?
will bring the teeth slightly together ~1-1.5mm of separation = the closest speaking space
if the denture wearer says 'S' and the post teeth are touching... this mean?
there is excessive Vertical DO
if the denture wearer says 'S' and the max and mand teeth barely touch... this means
decrease VDO
denture fabrication w/ excessive VDO results in...
trauma to supporting/ underlying soft tissue
increased VDO can result in...
clicking
decreased VDO can result in...
cheek biting
M sound
(EMMA)
brings mandible to its rest position
burning sensation of lower denture caused by?
impingement of mental nerve
denture base type that is NOT light cured?
resin type
why don't you set denture teeth on the incline up towards the retromolar pad?
it will dislodge the denture
why should mand molar not be placed over the ascending area of the mand?
the occlusal forces over the inclined ramus would dislodge the mandibular denture
you just deliver a CD, the pt. comes back w/ generalized soreness along the ridges (no sore spots, nothing visible clinically)... whats causing this?
significant malocclusion (hyper occlusion)
- how to fix... adjust occ
pt. has worn denture for 19 yrs, and now has a lesion under denture... what do you do?
relieve denture in area/ re-evaluate in 2 weeks... if doesn't go away then biopsy (incisional)
main reason for removing denture at night
relieve bone/ tissues
when tx planning RPD what is the 1st attachment placed on the surveyor?
analyzing RDP
when tx planning RPD whats the 1st thing you do..
mount casts
best way to evaluate available space for rests?
mounted casts
pt. has denture that has made tissue inflamed, before making a new denture what do you do...?
apply tissue conditioner to existing denture
at what apt. do you check for sibilant sounds?
when verifying VDO (intermaxillary records apt)
a lingual denture is good if...
you have full movement of the tongue
if teeth on wax try in don't occlude like they did on articulator, what do you do?
remount, reset, retry
what is an issue for denture pts?
mand dentures
retention of saliva is impacted by?
saliva flow
saliva & denture
(Retention - peripheral seal)
relationship that leads to denture and tissue adhesion
thin watery saliva
better and aids in adhesion
a lot of saliva...
is better for retention
disadvantage of reduced salivary flow...
reduced denture retention
physiologic rest movement
when mand and all supporting muscles are in resting posture
*muscle guided position
no posterior teeth and wear on anterior incisal edge... why?
bc no posterior teeth
pt. feel fullness of upper lip after denture delivery... why?
overextended labial flange
which position depends on pt. posture
VDR
decreased VDO =
increased interocclusal and freeway space
angular chelitis is caused by...
- decreased VDO (over closure) / increased interocclusal space
- fungal infection
pt. has short lower face and sagging lips.. cause?
decreased VDO
cheek biting w/ dentures is caused by..?
- insufficient VDO
- not enough horizontal overlap of posterior teeth
you fit a new denture and pt. complains of cheek biting... what do you do??
grind buccal of lower teeth
clicking of denture teeth... cause?
excessive VDO (= too little VDR and inadequate resting space)
exam of denture pt. reveals that retromolar pad contacts max tuberosity at the VDO... what do you do?
reduce max tuberosity surgically only
immediate denture has undercuts and tuberosity... what do you do?
reduce the maxillary tuberosity surgically only
in an edentulous pt. the coronoid process can...
limit the thickness of the denture flange in the maxillary buccal space
when taking impression and the pt. is open what can interfere with full seating?
coronoid
coronoid process can displace upper denture if:
too bulky at max DB
when mouth is open this can dislodge denture
coronoid (mand denture--> masseter)
open mouth while max border molding...
coronoid process will block buccal extension
best way to prevent speech problems in CD?
keep teeth in same position
need to increase VD by 4mm in denture pt, what do you do?
take a new CR and remount
the condylar guidance is increased from 20 to 45 degrees, what do you do?
increase compensating curve (and decrease incisal guidance)
when setting condylar inclination on articulator.. what do you do w/ the pin?
remove it (lift it up)
incisal guide pin posision why checking protrusive.. why?
determines condylar guidance
reason for incisive guide table?
anterior guidance (lift pin 2mm)
best way to preserve anterior guidance?
translating the horizontal and vertical relationships onto the incisal table
what plane is most important on anterior guidance?
horizontal/ occlusal
pt. w/ class III will have mand incisal angle.....
decreased
case: lower natural anterior teeth, upper PFM anterior teeth... why do lowers have incisal wear?
heavy incisal guidance
lower and upper teeth at edge to edge position...
incisal guidance position
when same pt. does anterior guidance.. TMJ??
TMJ Translates
CD try in, protrusive excursion results in separation of posterior teeth (denture dislodging)... how to correct?
increase compensating curve
reline for Kenney Class I (distal extension)... you must first make sure...?
try in framework and make sure it is seated!
in max CD opposing mand bilateral distal extension (kennedy I) why is the anterior of the wax rim beveled?
length is good esthetically but there is not enough interocclusal space (inter arch length) @ that length
pt. has occlusal rims prepared and bevels the max... why?
length of occ rim is adequate but VDO is wrong
how should distal extension RPD fit in comparison to other RPDs?
passive clasp fit
best way to treat a tooth supported lower denture?
use metal copings to cover teeth
retruded tongue habit w/ full denture means what?
difficulty swallowing
denture border sitting on what muscle due to its orientation of its fiber...
masseter
posterior buccal extension of a mand CD is limited by..
masseter
what muscle can you impinge on w/ denture?
masseter
what muscle covers denture flanges and does not affect stability?
buccinator
the denture base completely covers what muscle?
buccinator
which muscle will not interfere w/ the denture base?
lateral ptergyoid
lower denture impression lingual area muscle
mylohyoid
which muscle helps border mold in the posterior lingual flange?
mylohyoid
lingual flange on lower CD is around which muscle?
mylohyoid
lingual flanges are affected by?
mylohyoid
what muscles determine lingual border of mand impression?
mylohyoid/ superior pharyngeal constrictor/ palatoglossus/ genioglossus
border molding of the lingual mand portion is done by what movement?
wetting of lips w/ tongue
you would relieve a mand denture in the area of buccal frenum to allow which muscle to function properly?
orbicularis oris
pt. present w/ restricted floor of the mouth, only 6 mand ant teeth and diastema/... which major connector do you use?
lingual plate w/ interruption in the palate @ the diastemas
RPD rocks when you apply pressure on either side of fulcrum line.. why?
indirect retainer
RPD pops off when you press on 1 side... why?
inadequate indirect retainer
insufficient indirect retention on RPD occurs when what happens?
distal extensions lift away from mucosa
multiple failures in FPD.. why?
poor framework design
what mechanical property effects permanent composition for RPD clasps
yield strength
base metal used for?
long span bridges (FPDs)
why do you use canine for incisal rest?
esthetics/ surface area/ cingulum
why is a rest designed on lingual surface of canine preferred to using an incisor?
less leverage is exerted against the tooth by the lingual rest
how do you protect roots under an overdenture
RCT w/ cast copings
what is not important for over-denture
clinical crown size
which teeth roots to retain under over denture?
mand canine
(canine, PM, incisor, molar)
endocrine involvement that is related to jaw deformity
acromegaly
if acromegaly is not controlled...
lower jaw protrudes
a pt. w/ acromegaly needs dentures... which arch will not fit
mand
denture pt. w/ a big ball around canine and PM..
neurofibroma
after suverying and designing which is the first step to do?
reduction of the axial for proximal plate
which kennedy class is a direct retainer very important?
II
describes a denture w/ bilateral edentulous space anterior to natural teeth...
kennedy IV
which type of kennedy does not have a modification
IV
corrosion resistant/ prevents corrosion
chromiun
what is expected from a high nobel meal?
no corrosion
what RPD denture frame metal causes allergy?
nickel
RPD metal most likely to cause allergic rxn?
nickel
pt. w/ completely edentulous maxilla and partially edentulous mand w/ preserved ant teeth
kelly/ combination syndrome
symptoms of combination syndrome
- denture anterior teeth don't show
- flabby ant ridge
- flabby and enlarged tuberosities
- lower ants extruded above occ plane
- atrophy of lower post ridge
- decreased VDO
which is not a symptom of combo syndrome?
increased VDO
ultimate goal for making UCD and lower RPD for pt. w/ combo syndrome?
balanced occlusion on both anterior and posterior teeth of mouth during centric relation
a flabby max ant ridge under a complete denture is frequently associated w...
retained natural mand anteriors
trisomy 21
down syndrome
down syndrome high or low caries risk?
low
midfacial hypoplasia/ deficiency
down syndrome
down syndrome manifestations
- small maxillas
- mid face deficiency
- prognathic mand
- Class III profile
- thickened tongues (macroglossia)
- delayed eruption
- microdontia/ partial anodontia/ short conical roots
- do not have higher caries risk
- DO have higher perio risk
what orthomanifestation does Turner syndrome and trisomy 21 associate with?
short midface
hyper- telorism
eyes wide apart
(increased distance between eyes)
hyper- telorism is seen in?
Crouzon's disease/ cleidocranial dysplasia/ gorlin/ down syndrome
which does not result in delayed development?
Trisomy 18 (Edward Syndrome)
fetal alcohol syndrome
anecephaly (absence of major portion of brain)/ mid face deficiency/ cleft lip
what causes problems in babies in embyro?
teratogen
teratogen
anything that messes w/ the fetal development (cause deformity/ birth defects)
synchondrosis
epiphyseal plate
at what age does mandibular symphisis close
6-9 months
sphenooccipital synchondrosis closure... what kind of tissue fills it in?
cartilage
condyle
intersititial growth
which undergoes closure latest?
sphenooccipital
synostosis
abnormal fusion of bones
craniosynostosis
early closure of suture between bones
Crouzon Syndrome
* Synostosis (abnormal fusion of bones)
*mid- face deficiency (max hypoplasia)
* ocular proptosis (bulging of the eye anteriorly out of the orbit)
*Beaten metal skull
Hunter Syndrome
- lack of enzyme iduronate-2-sulfatase (I2S)
- enlarged tongue
- mental retardation
Hurler Syndrome
- buildup of mucopolysaccharides
hunter and hurler syndromes have what in common
mucopolysaccaridosis- build up of GAGs
Papillon-Lefevre Syndrome
- palmar/ plantar hyperkeratosis
- severe perio disease
- premature loss of primary and permanent --> edentulous
- see in young kids!
Pierre Robin Syndrome
- cleft palate
- glossoptosis (downward displacement/ retraction of tongue)
- absent gag reflex
- Mircognathia
*smaller than normal mandible--> tongue falls back in the throat --> difficulty breathing
sturge webber syndrome
*vascular malformation (eye and hemangioma)
*port wine stain
alveolar bone is open over root
fenestration
'hole' in the bone that exposes the root?
fenestration
the loss of buccal or lingual bone overlying a tooth root
dehiscence
characteristic oval
dehiscence
each of the following osseous defects would be classified as infra bony except
(trough, dehiscence, hemiseptum, interdental crater)
dehiscence
what is NOT an endocrine gland?
(parathyroid, thyroid, adrenal, parotid)
parotid
give a child Vit D or Ca for?
Hypoparathyroidism
Tachycardia and Hypertension
Thyrotoxocosis Shock
(Hyperthyrodism)
sweating (heat intolerance), weight loss, tachycardia, fine hair
hyperthyroidism
graves disease (exopthalmos)
hyperthyroid
thyroid storm
hyperthyroid
weight gain, bradycardia
hypothyroidism
increase in alkaline phosphatase (ALP)
hyperparathyroidism
decrease in alkaline phosphatase (ALP)
hypophosphatasia
CGCG is seen in ps. w/....
hyperparathyrosidm
Brown's Tumor
osteoporosis is associated w..?
hyperparathyrodism
drug for hyperthyroid, doesn't let iodine bond to horomone
Radiated Iodine
drug for hypothyroid
levothyroxine
pheochromocytoma involves..
thyroid
pt. has high cholesterol, high BP, diabetes, MBI of 36... what problem does he have?
metabolic syndrome
normal % of fat intake per day
30%
fenestration/ dehiscence
most likely cause of failure in the pre-ceramic soldering technique is...
overheating the parts to be joined together
do NOT use GI resin cement for all ceramic restoration....
EXPANSION due to water absorption could crack porcelain
*Zirconia is exception
casting shrinkage of cobalt-chromium allows...
2.2%
HIGH compressive strength + LOW tensile strength
brittle
- higher melting point, yield strength, hardness
- lower specific gravity
GOLD properties
cast gold onlays > cuspal coverage amalgams
have higher compressive strength and more precise inter proximal contacts
thinnest portion of wax pattern...
in deepest part of the ring
(*attach sprue to thickest area of crown)
increased H2O of gypsum =
more setting time, less expansion and strength
Flux (Borax)
displaces gases, dissolves corrosive products, removes oxides from metal surfaces
anti-flux
graphite
shrinkage porosity in a gold casting is associated w/..?
sprue diameter TOO THIN --> back pressure porosity --> will get rounded margins
casting ring liner
compensate for casting metal expansion (uniform investment expansion/setting)
#1 reason crown doesn't seat
proximal contact
most important area to have thickness of metal on FPD connector area
occluso-gingival
where are retentive grooves placed on crown prep
interproximal
post length..
2/3 to 3/4 root or length of crown
PFM
metal CTE slightly higher than porcelain
20-40?m
space for cement
most traumatic effect on abutment/ cantilever
the more posterior position of the tooth the more force on cantilever
where to split FPD
between pontic and retainer
male/female abutments placed...
DISTAL of pier abutment, prevents mesial drifting
wrought wire clasp
flexible
*used for perio involved teeth
RPD rocking on fulcrum line
problem w/ indirect retainer
RPD fit
Passive
where does clap fit
infrabuldge
rigidity
major connector
lingual bar ____mm
needs 8mm
intermediate abutments aka
pier abutments
The PDL surface area of abutment teeth should be equal to or greater than the imaginary PDL of the missing teeth
Ante's LAw
what is contraindicated in upper with Combination Syndrome?
Complete denture upper
excess cement can cause
peri-implantitis
what controls the setting rate in Alginate
Trisodium phosphate
CR measures the
condyles
orients maxillary cast to skull via external auditory meatus to stabilize the bow
Arbitrary Facebow
HCL is what
Horizontal Condylar Inclination
30 degrees
articulator where condyles are part of the lower member
ARCON
casts poured from alginate are more accurately mounted with
wax records
casts poured from elastomeric materials are more accurately mounted with
elastomeric materials
ZOE paste or PVS
posterior determinant of occlusion
Condylar Guidance
Anterior determinant of occlusion
Incisal Guidance
Anterior guidance =
Incisal guidance + canine guidance
mechanical incisal guide table gives insufficient information to reproduce the ____ of natural teeth
lingual contours of maxillary anterior teeth
color change between soft and hard palates
Butterfly Line
muscle attachment for Mandibular labial frenum
orbicularis oris
muscle attachments for upper and lower buccal frenums
- buccinator
- orbicularis oris
mandibular lingual frenum muscle attachment
genioglossus
muscle attachment for maxillary labial frenum
NONE
Retromolar Pad contains 4 attachments
1) Pterygomandibular Raphe
2) Buccinator
3) Superior Pharyngeal Constrictor
4) Temporalis
analogous to coronoid process
masseteric notch