Assembly of anterior and posterior teeth in total prosthesis
Plan
- Definition
- The objectives of the assembly
- Choosing artificial teeth
a-Materials
b/Shape of artificial teeth
c/Shade of artificial teeth
d/Dimension of artificial teeth
- The rules of editing
- Gysi assembly
- Assembly of the anterior teeth
A. Assembly of the upper anterior teeth - Upper central incisors
- °Upper lateral incisors
- °The upper canine
- B. Assembly of the lower anterior teeth
- °Lower central incisors
- °Lower lateral incisors
- The lower canine
- Fitting of posterior teeth (According to Gysi)
- The superior posterior block
- a. Assembly of the upper first and second premolars
- b. Mounting the upper first molar
- c. Mounting the upper second molar
- The lower posterior block
- a. Mounting of the first lower molar
- Fitting the second lower premolar
- Assembly of the first lower premolar:
- Wax Finish
- Testing the assembly:
- OTHER TYPES OF MOUNTING:
- A/unconventional assemblies with anatomical teeth:
- B/non-anatomical montages:
- The adjusted assembly
- Conclusion
- References
DEFINITION
This is the work phase in the laboratory which consists of making a wax model bearing artificial teeth which will prefigure the final prosthesis, the assembly must ensure aesthetics and function.
The well-designed assembly of artificial teeth constitutes one of the factors of balance of the dental prosthesis in the edentulous.
ASSEMBLY OBJECTIVES
- Restoration and preservation of function: Aesthetics, phonation, mastication, etc.
- Ensure the durability of prosthetic retention during the functional dynamics of the masticatory system.
- Maintain as much as possible the biological integrity of the support surfaces on the osteo-mucosal plane.
Choosing artificial teeth
They will be chosen according to the following 4 criteria: materials , shape , color , size .
a-Materials
Assembly of anterior and posterior teeth in total prosthesis
b/Shape of artificial teeth : depends on:
-The shape of the face : there is an inter-relationship between the shape of the central incisor and that of the face (Williams), NELSON triad : (face – arch – central incisor):
- Long face means long teeth
- Short face means short teeth
-The genre:
- For women, the teeth are rather rounded with a smooth shape.
- For men, the teeth are horny and angular.
-age : the person is old: the teeth are stocky (abraded with thick free edge).
– the profile : straight (flat tooth); convex (rounded)
– personality : frush and fishes : classify personalities into 3 groups:
the vigorous: with very visible central incisors; robust and primitive in appearance (evoking the bull)
the delicate: with fragile central incisors; fragile and erased
intermediates: constituting the majority with teeth; pleasant; moderately robust.
c/Shade of artificial teeth: It is necessary to make the choice in daylight and not under electric light. It may change the shade of the remaining natural teeth by reflection.
Important : skin color: – light skin (yellowish tooth) – dark skin (tooth……) This is a function of:
1/ general elements:
- age: the older the patient, the yellower the tooth; saturated; less shiny; less translucent.
- gender: clearer in women than in men.
- personality: + the subject is delicate + the tint is light.
- + the subject is vigorous + it is saturated and pigmented.
- ethnic characteristics: clearer among Westerners than among Easterners;
+ dark among black people or among Indians.
2/depending on the frame:
- (wood and clapp…): you have to seek harmony with the skin:
- light skin (yellowish tooth); dark skin (grayish yellow tooth)
- (SAVAGE): harmony with the eyes is essential:
- brown eyes correspond to: yellow teeth.
- blue eyes correspond: yellow teeth bordered with gray.
d/Dimension of artificial teeth :
It will be chosen based on the remaining natural teeth on the arch and the orientation of the occlusion model.
- Some analyses:
- Justification index M / D 6 anterior teeth: 1/5 of the inter-trigonal or inter-tuberosity distance.
- Width (ant): LEE index (2 the width of the nose: ic = ¼)
- Length: 4 teeth post = F . D . canine – before trigone (tuberosity).
- Height: ½ inter-ridge distance, Smile line, phonation (FE . VE), Vertical dimension, Lips: the free edge of the teeth must exceed the upper lip at rest by 2mm).
THE RULES OF ASSEMBLY
- The anterior teeth must be located between the top of the crest and the vestibular slope of the latter (Air of support <: ACKERMANN ).
- The upper and lower central incisors should be mounted first on either side of the midline.
- The vestibular surfaces of the anterior teeth must be in harmony with that of the natural teeth on the arch and must restore the curvature of the arch in order to restore the patient’s physiology.
- The free edge of the upper central incisors should be parallel to the upper lip and visible 1 to 2 mm when the latter is at rest.
- Over jet and over bite must be respected in order to restore phonation and mastication.
- The lower posterior block must respect the pound air : between the Mesial Face of the canine towards the lingual side of the trigone and the Distal Face of the canine towards the vestibular side of the trigone.
- symmetry : PM and M must be mounted symmetrically on either side of the SM plane
- The upper palatal cusps must be mounted vertically above the lower ridge line.
GYSI ASSEMBLY
I. Assembly of the anterior teeth
A. Assembly of the upper anterior teeth
Generally, it is the occlusion model which guides the arrangement of the anterior teeth:
°situation of the free edge of the incisors;
°the median axis;
°the situation of the vestibular faces ensuring the aesthetic support of the lip.
- Upper central incisors:
*frontal plane: -free edge in contact with the POP;
-on both sides/median sagittal axis.
*sagittal plane:
– slightly lingual collar (intermediate position between the canine and the lateral);
-the free edge is 6 to 8 mm from the center of the retro-incisive papilla.
- °Upper lateral incisors:
*frontal plane: -the free edge above the POP (1 or 2 mm);
-the axis inclined from 5° to 10°.
*sagittal plane: -very inclined (10°).
- °The upper canine:
*frontal plane: -the tip in contact with the POP
-the major axis can be inclined distally from 0° to 5°
*sagittal plane: -vertical axis.
B. Assembly of the lower anterior teeth
°Lower central incisors:
*Frontal plane: -free edge in contact with the POP;
-vertical axis.
*Sagittal plane: -slight inclination in the linguo-vestibular direction;
-the heels can be placed 1 to 2 mm in front of the top of the crest.
°Lower lateral incisors:
*Frontal plane: -free edge in contact with the POP;
– vertical axis.
*Sagittal plane: -major vertical axis.
The lower canine:
*Frontal plane: -cusp in contact with the POP;
-axis slightly inclined in the mesio-distal direction.
*Sagittal plane:
– inclined in the vestibulo-lingual direction in order to avoid cusp catching during lateral movements;
-the heel mounted in front of the lower ridge.
Assembly of anterior and posterior teeth in total prosthesis
Assembly of the anterior-inferior teeth
II. Assembly of posterior teeth (According to Gysi)
- The superior posterior block
- a. Assembly of the upper first and second premolars
- The 1st PM touches the POP by its two vestibular and palatine cusps (bicuspid contact)
- The 2nd PM touches the POP by its palatal cusp.
- b. Mounting the upper first molar
- Only the mesiopalatal cusp comes into contact with the prosthetic occlusal plane
- Its occlusal surface is inclined upwards and backwards. It forms an angle of 6° with the occlusal plane (ant/post).
c. Mounting the upper second molar
- The 4 cusps do not come into contact with the occlusal plane. The mesiopalatine cusp is closest to it.
- This second upper molar is mounted in the extension of the occlusal face of the first upper.
- This twisting movement intended to reproduce the anteroposterior compensation curve called “ Curve of Spee ” can be more or less accentuated depending on the shape of the lower crest.
THE LOWER POSTERIOR BLOCK
- a. Mounting of the first lower molar
- It constitutes the key tooth of occlusion.
- Normal assembly (Angle class 1: the lower first molar is half a cusp forward of the upper molar )
- The mesiopalatal cusp of the upper first molar must fully engage the central fossa of the lower molar to achieve a correct overjet.
- Maximum contact must be ensured between the teeth of the two arches.
- Fitting the second lower premolar
- The buccal cusp of the lower second premolar must mesh with:
- The distal slope of the upper first premolar
- And the mesial slope of the second upper premolar
- Fitting the first lower premolar: ( If we have the space necessary to accommodate this tooth )
- The vestibular cusp of this tooth meshes with:
- The distal slope of the upper canine.
- And the mesial slope of the 1st lower premolar.
- Wax Finish
- The false gum should be given a natural and shiny appearance.
- The wax must be perfectly polished.
- And a healthy, non-pathological gum appearance.
- Respecting the thickness of the base (1 to 2 mm)
- Testing the assembly:
In order to avoid significant changes after polymerization, the operator must check the following:
-appreciation of aesthetics;
-the DV and RC;
-the final phonetic test;
-take the patient’s opinion.
OTHER TYPES OF MOUNTING:
A/unconventional assemblies with anatomical teeth:
- M. Spheroidal .
- M. Physiological of PATERSON .
- Mr. ACKERMAN’s Helical .
- Mr. de GERBER .
B/non-anatomical montages:
- SEARS assembly .
- FRUSH assembly .
- Evolutionary assembly for therapeutic purposes (conditioning, etc.)
- Animated Montage……
CONCLUSION
The assembly is clinically validated, then the polymerization is carried out rigorously in order to best control the occlusal modifications which could occur by retraction of the resin .
Assembly of anterior and posterior teeth in total prosthesis
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