Try in dentures

Try-in Verification / Aesthetic try-in definition

A preliminary insertion of a removable denture wax- up or a partial denture casting or a finished restoration to determine the fit, aesthetics, maxillomandibular relation

Trial denture definition

A preliminary arrangement of denture teeth that has been prepared for placement into the patients mouth to evaluate aesthetics & maxillomandibular relationships

importance of trial denture

It is the last opportunity to evaluate many of the previous steps already accomplished

objectives of try in denture

* check and verify established maxillomandibular relationship
* determine if positions of teeth and contours of denture bases are compatible with surrounding oral environment
* verify tooth selection and arrangement for esthetics and phonetics

To check and verify the established maxillomandibular relationship:

* Verify that centric occlusion and centric relation coincide.
* Test for the acceptance of the established vertical dimension of occlusion.

Various aspects of try in:

* Extraoral examination of the trial dentures.
* Intraoral examination of the trial dentures.

Extraoral examination of the trial dentures:

* on master cast
* on trial denture bases
* on articulators
* check teeth

finished denture is processed on

master cast

master cast should be

* In good shape.
* Free from air bubbles or scratches.
* Free from wax debris which lead to improper adaptation of the trial denture bases leading to false relationships.
* If there are any undercuts present in the cast, these undercuts should be relieved to avoid scratching of the cast by the trial denture bases.

what is checked on the trial denture bases

* stability
* border should be smooth, round, and have no sharp edges
* border should be shaped to conform to the depth and width of the sulci

mounted cast on articulators is checked for

* maintenance of the vertical dimension of occlusion


* that mounting rings are firmly screwed in their position
* articulator can be moved smoothly from centric to eccentric positions without cuspal interlocking
* that the trial denture bases lie properly on their casts and the teeth meet evenly in centric relation

for the teeth its the dentists responsibility to

select the proper shade, and mould of the teeth and to determine that the teeth are set correctly

elimination of excess wax is done to

avoid the camouflages of the teeth relationships to overlook the occlusion

Intraoral Examination Of The Trial Dentures

* checking the trial dentures separately
* checking the upper and lower dentures together

To reduce the risk of cross- contamination, what is done?

trial denture should be sprayed with suitable antiseptic solution and washed in running water, before inserted in patient mouth

what happens if there is over extension of flanges

* will stretch the sulcus tissues
* when denture is inserted eads to elastic recoil resulting in dislodgment of the denture
* immediate denture displacement after its seating

examination of labial and buccal extension

* insertion of upper trial denture in place with light pressure
* move cheeks in functional movement

denture base extension needs adjustment until

little or no movement occurs

under extension of the upper trial denture leads to

poor physical retention

correction of denture base extension entails

making a new final impression

Provision of the frena {labial and buccal} should be done to ensure

that they have adequate cleara

posterior border of the upper trial denture base should extended from

one hamular notch to the other along the vibrating line of the soft palate

advantages of placing the posterior palatal seal in trial dentures

* trial base is more retentive producing more accurate maxillomandibular records
* patients can feel the retention giving them psychological security
* patient can realise the posterior extent of the denture

why is the retention of the trial denture less than the completed denture

* absence of posterior palatal seal
* poor adaptation of tral denture base to tissues

looseness of upper trial denture leads to

* inaccurate assessment of occlusion especially for patients with unfavorable anatomical features

How to test the retention of upper denture?

* Seat the upper trial denture with a firm upward and backward pressure.
* Allow the tissues to settle around the denture
* Grip the labial and lingual surfaces of the upper denture teeth between the thumb and forefinger
* Apply a firm downward vertical pull to dislodge the denture away from the tissues
* If the retention is good, dislodgment of the trial denture may be difficult

stability of upper trial denture base is tested by

applying pressure directed at right angles to the occlusal surface where displacement does occur in a tissueward direction with the ball of the index finger in the premolar and molar regions on each side alternately

causes of instability of upper trial denture base

* Warpage of the denture base.
* Posterior teeth set buccal to the underlying alveolar ridge
* Hard unrelieved area in the midline e.g. torus palatinus.

Properly oriented occlusal plane is important to:

* Patient esthetics.
* Patient comfort
* Chewing function
* Balance of occlusion

Orientation of the anterior end of the occlusal plane is determined by

esthetics

amount of the upper anterior teeth that will be seen during speech and facial expression depends on

length and movement of the upper lip

If the upper lip is relatively long

natural teeth may not be visible when the lip is relaxed or even during speech

why does the amount of visible upper teeth vary for each patient

movement of the lips during function varies considerably among patients

how should the lower trial denture extension be tested

with the patient mouth is opened no more than half opened position to allow the surrounding musculature is in an acceptable state of relaxation

Testing of the lower trial denture retention:

1. Ask the patient to open his mouth slightly and let his tongue touch the cingula of the lower anterior teeth, support the chin of the patient with the left hand and pull the teeth straight upwards to check the retention of the anterior labial and lingual flanges.
2. Tilt the lower trial denture outward from the canine region to test the retention of the opposite retro molar pad.

Usually the lower denture retention is poor when compared to the upper denture due to:

1. Small denture bearing area
2. difficulty in obtaining an efficient border seal

in most patients where are the incisal edges of the natural lower canines and the cusp tips of the lower first premolars located

at the level of the lower lip at the corner of the mouth when the mouth is slightly open.

posterior end of the lower occlusal plane should be at

the level of the anterior two thirds of the retromolar pad

where should the lower artificial teeth be set in

neutral zone

neutral zone is

where natural teeth occupy a position in the mouth where the inward pressure of the lips and the cheeks is neutralized by an equal and opposite outward pressure of the tongue

to check for the neutral zone in the patient’s mouth

* patient opens mouth half way and touches lower anterior teeth with tip of tongue while tongue is relaxed
* Feel the amount of pressure exerted by the tongue and cheek on the lower teeth, using a plastic filling instrument
* Pressure should be roughly equal on the lingual and buccal sides of the teeth

If the tongue is more mobile than the cheeks this’ll cause

greater instability of the lower denture

Cramped tongue may be due to:

* posterior teeth set lingually to neutral zone
* posterior teeth tilt lingually
* Posterior teeth too broad bucco-lingual

Testing of the tongue space:

Ask the patient to raise the tongue. If the tongue is cramped, the denture will begin to rise immediately. As the tongue moves it tries to expand laterally and whenever the tongue moves the denture will move

checking upper and lower trial dentures together

* lower trial denture inserted first to reduce chances of having the upper trial denture drop down
* patient should be seated in an upright position
* patient head is not supported by the headrest

why is the patients head not supported by the headrest when checking upper and lower trial dentures together

headrest may effect the physiologic rest position of the mandible so, it effect the amount of interocclusal distance

Perfection & Verification of Jaw-relation records is done by

* verifying vertical dimension
* verifying centric relation

verifying centric relation is done by:

* intraoral observation of intercuspation
* extra oral articulator method

Intra Oral Observation of Intercuspation

* patient is guided into centric relation by a thumb placed on the anteroinferior portion of the chin & index finger bilaterally on the buccal flanges of the lower denture
* error in centric relation is apparent if teeth slide over each other

If Error in centric relation is due to mounting

* anterior teeth if not placed to support lip, are corrected.
* vertical overlap of anterior teeth are carefully noted .
* posterior teeth are removed from lower occlusal rim
* Impression plaster is mixed & placed on the rim.
* Pt. is instructed to close the mouth slowly until the anterior teeth have same vertical overlap as they had before the posterior teeth were removed.
* After the plaster is set, rims are removed & this corrected new record is mounted on a articulator.
* centric relation is confirmed
* trial dentures are locked in articulator
* opposing teeth should fit in the indentation in every way (anteriorly, posteriorly, laterally & vertically ) if the original CR was correct
* If it does not fit, mandibular cast should be separated & remounted with last occlusal record

Extra oral articulator method

* Impression material is placed over mandibular posterior teeth
* wax sealed
* denture placed in mouth
* just wax portion is immersed in water bath of 130F for 30 secs
* denture placed back in pts mouth
* mandible guided into CR so that upper teeth makes contact with the wax
* denture removed & chilled in ice water & returned back to patients mouth for re-checking

verifying vertical dimension is done by

* checking labial frenum
* Evaluation of Vertical dimension at rest & at occlusion
* pre extraction records
* amount of interocclusal distance to which pt. was

accustomed
* phonetics & esthetics
* facial dimension & facial expressions
* lip length in relation to teeth
* inter arch distance & parallelism of the ridges

Assess trial dentures for:

1. Proper facial/labial support
2. Aesthetics – shade, size and set-up of anterior teeth
3. Phonetic function
4. Correct occlusal relationships – verify records made at jaw relationship stage

when patient smiles, necks of teeth are

not seen

Wax rim/tooth display can be adjusted with

sex, age, and lip length

if lip length is 10-20 mm incisal display is

3-4 mm

if lip length is 20-25 mm incisal display is

2 mm

if lip length is 26-30 mm incisal display is

1 mm

if lip length is >30 mm incisal display is

0 mm

for a young female incisal display is adjusted by

adding 2 mm

for a middle aged female incisal display is adjusted by

adding 1 mm

for a young male incisal display is adjusted by

adding 1 mm

for a middle aged male incisal display is adjusted by

not adjusted

for an old male incisal display is adjusted by

subtracting 1 mm

for an old female incisal display is adjusted by

not adjusted

Verification of Records:

* Visual Check of Occlusal Relationship- patient does not looked strained, overclosed
* Check OVD with Phonetics
* Make New Centric Relation Record- if incorrect

Visual Check of Occlusal Relationship

* Teeth should appear to occlude simultaneously
* Teeth should appear to contact simultaneously when closing into a centric relation position

If the teeth contact when the patient tries to say “S”

OVD is excessive or the trial bases need to be stabilized

how to check OVD with phonetics

ask patient to say S

when making a new centric relation record it should

match mounting

reasons why the new centric relation record doesn’t match the mounting record

* Record just made is inaccurate
* Record made at last appointment is inaccurate
* Errors made during mounting

when Approving Wax Try-In:

* Don’t Give Patient Mirror Until You Are Satisfied with the Appearance
* Try to Distract Patient from “Feel” of Denture: (will feel different when processed)
* Let Patient See Wax Dentures

Approval of Wax Try-In:

* Check fullness of lips
* Check occlusal plane: (Fox plane instrument)
* Check tooth display
* Check color and arrangement

After evaluation, adjustments and patient consent

prostheses are sent to the lab for processing

before prostheses are sent to lab what is done

posterior palatal seal is carved

Making the Posterior palatal Seal:

* Determine posterior palatal seal area in the mouth


* Groove out the PPS area

movements of articulator should simulate

movements of the patient within the range of normal functional contacts of teeth

Appearance of entire lower half of face depends on

dentures

To obtain a harmonious effect with the patient face

modifications are made in arrangement of teeth

Preliminary selection of artificial teeth

* Evaluated for size, form & color
* 6 anterior teeth should be of sufficient overall width to extend approx. corner of mouth
* Color should blend with the face
* Any records used in initial selection should be consulted & changes should be made if it improves the appearance of patient

Teeth set directly over ridges causes insufficient lip support characterized by

* Drooping of corners of mouth
* Reduction in visible part of vermilion border
* Deepening of nasolabial sulcus
* Wrinkles over vermilion border

Excessive lip support causes

* stretched lips
* tendency of lips to dislodge dentures during function
* elimination of normal contours of lips, philtrum & sulci

Labial surface of many natural central incisors are

about 8 – 10mm from center of incisive papilla

to check for vertical orientation of anterior teeth

* Index finger is placed on incisive papilla with relaxed upper lip & amount of finger covered gives indication of length of upper lip
* Incisal edges of lower canine & cusp tip of lower first premolar are even with corner of mouth when mouth is slightly open

what is the best guide for vertical orientation of anterior teeth

Lower lip is a better guide for vertical orientation of anterior teeth

if lower teeth are above corner of mouth when mouth is slightly open, it’s because

1. plane of occlusion may be too high
2. vertical overlap of anterior teeth may be too much high
3. vertical space between the jaws may be excessive

Inclination of labial surface of residual ridges seen on edentulous cast gives guide to

inclination of anterior teeth

Inclination of anterior teeth parallels the

profile line of face

types of dental arch form & form of residual ridge:

* square arch form
* tapering arch form
* ovoid arch

to get square arch form

* Central incisors are more nearly in line with canine
* 4 incisors should have little rotation to give broader effect to teeth

to get tapering arch form

* Central incisors are greater distance forward from canine
* rotating or lapping of teeth may be present

to get ovoid arch form

* teeth seldom rotated
* show greater amount of labial surface

Harmony of long axis of central incisors & face

* Imaginary perpendicular line from mid point of Interpupillary line should mark middle of dental arch to be in harmony with face


* Mid line also determined by observing position of incisive fossa
* Mid line of mandibular central incisor is aligned with that of maxillary incisors

Harmony of the teeth with smiling line of the lower lip

* Line formed by upper anterior teeth should follow curved line of lower lip during smiling


* Vertical positioning of upper canines are responsible for shape of smile line

what should be done to avoid a reverse smile line

Canines should be arranged in such a way that their incisal edges should be slightly shorter than that of lateral incisors

frequent cause of artificial appearing dentures

* reverse smile line

Harmony of opposing lines of Labial & Buccal surfaces

* Asymmetrical symmetry is essential for natural appearing teeth
* Labial & buccal lines should be in harmony with lines of face

to achieve Asymmetrical symmetry, If maxillary right lateral incisor is set at 5 degrees to perpendicular then opposing lateral should be

of same angle but in opposite direction

Harmony of incisal wear & age

Incisal edges of denture teeth should be grinded to simulate the wear surface that would have developed by the time patient reached his current age

Use of spaces between teeth can be effective in

emphasizing individual tooth position & natural appearing arrangement