WAX PATTERN Flashcards
Steps of wax pattern fabrication
1-Coping fabrication
2-Axial contouring
3-Waxing of occlusal morphology 4-Margin adaptation and finishing 5-Evaluation, finishing, and polishing
Emergence profile
The part of the axial contour that extends from the base of the gingival sulcus To the height of contour, the emergence profile should be straight or concave To facilitate access for oral hygiene
The two principal objectives of Margin finishing
(1) minimizing dissolution of the luting agent and (2) facilitating plaque control.
defects may happen during fabrication of cast restoration At the margins
include :
1-over-hanging margins (thick margin)
2-over-extended margins
3-under-extended margins
4-open margins
the wax pattern will be….
duplicated exactly through The investing and casting technique, the final restoration will be exactly as the Wax pattern
There are two accepted ways of fabricating a wax pattern:
1-The direct technique, in which the pattern is waxed on the prepared tooth in The mouth
2-The indirect technique, in which the pattern is waxed on a stone cast made From an accurate impression of the prepared tooth
Types of wax used in wax pattern construction
Type 1-for intra oral patterns, inlays, post& core
Type2-for extra oral pattern construction , cases of crown & Bridge
Requirement of inlay wax include :
1- should be of different color than that of the die
2-should flow readily when heated
3-should be rigid when cooled
Consistency of type II inlay wax :
1-soft inlay wax
Used in fabrication of initial layer of wax pattern (coping fabrication)
2-medium consistency inlay wax
ed in build up of the bulk of the wax pattern contour
3-hard consistency inlay wax
Used at the margin to prevent any wax distortion at the margin
Steps of wax pattern fabrication
1-Coping fabrication
2-Axial contouring
3-Waxing of occlusal morphology
4-Margin adaptation and finishing
5-Evaluation, finishing, and polishing
Methods of coping fabrication
1-Dipping method
2-Addition method
3-Molten press method
should be observed during waxing of axial surfaces
1-Contact area
2-Hight of contour
3-Embrasures
4-Emergence profile
The location and size of contact area should be determined in wax pattern, meaning ?
Occluso- gingivally most posterior contact areas are located in the occlusal third Of the crown except for the contact between the maxillary first and second molar which located In the middle third
Facio-lingually most posterior teeth contacts are located slightly to the facial Aspect of the middle of the posterior teeth except for the contact between The maxillary first and second molars which are centrally located.
A pinpoint contact may cause
food impaction between
Too large contacts can
encroach on gingival embrasure Which make plaque control very difficult and lead to Periodontal disease
Height of contour on the facial surface of posterior teeth on
the cervical third
Height of contour on the lingual surface on the
middle third ,except in the Maxillary premolar and molar in the cervical third
Amount of height of contour on the buccal and lingual surface
facial contours , 0.5mm beyond the out line of root at CEJ
lingual surfaces , 0.5mm on all maxillary posterior teeth and Mandibular first premolar, about 0.7mm on mandibular second premolar and 0.1mm on mandibular molars.
In the Negative waxing technique
Bring the Working and opposing casts together
WAX-Added technique also called
(positive waxing technique) + occlusal features like cusp tips (called cones)
In requirements of properly waxed occlusal surfaces, The cusps and ridges of occlusal surfaces should be………Without……..
shaped to allow even contact With opposing teeth , interferences in centric and eccentric
During wax pattern fabrication in centric occlusion position should be three Point contacts (ABC) which are
A-contacts: between lower buccal and upper buccal cusps
B-contacts: between lower buccal and upper palatal cusps
C-contacts: between the lower lingual and upper palatal cusps
- B-contacts are the most important
Depending on the position of contacts there are two types of occlusal arrangement
1-cusp-marginal ridge occlusion
2-cusp-fossa occlusion
During cut back of wax patterns for metal-ceramic restorations, the exact amount Of space required for porcelain can be determined using either of two methods:
1-Use of depth orientation grooves
2-Use of putty index
