checking the design of prosthesis in complete absence of teeth

1. medical errors in
determining the
central ratio of
the jaws

2. For patients who have lost all of their teeth, a full denture is often recommended to restore their ability to chew, speak, and
smile. The process of making a full denture involves several clinical and laboratory stages to ensure its proper fit and
function.
First, the dentist will take impressions of your mouth, capturing the shape of your gums and any remaining oral structures.
These impressions are then sent to a dental laboratory, where skilled technicians will use them to create a wax model of
the denture.
In the case of a patient with a full absence of teeth, the central ratio is utilized to establish the proper alignment and
positioning of the upper and lower denture teeth. The central ratio refers to the relationship between the central incisors
(the front teeth) and the midline of the face.
During the wax try-in stage, you will be asked to try on the wax model denture. This allows the dentist to assess the
correctness of all previous stages and make any necessary corrections. The dentist will carefully evaluate the alignment of
the central teeth with your facial midline and make adjustments as needed.
The goal is to achieve a harmonious and natural-looking smile that complements your facial features. The dentist will also
ensure that the denture properly fits your gums and functions well when you bite and chew.
If any corrections are needed, the dentist will communicate with the dental laboratory to make the necessary adjustments
to the wax model. This process may involve refining the position and alignment of the teeth, as well as addressing any
concerns related to the fit and comfort of the denture.
Once the corrections are made, the final prosthesis will be fabricated based on the updated wax model. It will be designed
to provide you with a functional and aesthetically pleasing set of teeth that restore your ability to eat, speak, and smile
confidently.

4. Steps of checking design of complete
dentures in edentulous jaws
CHECKING THE
WAX DENTURE
IN THE ORAL
CAVITY
VERIFICATION OF
THE DENTURE
DESIGN IN THE
OCCLUDER OR
ARTICULATOR
CHECKING THE
DENTURE DESIGN
ON MODELS
AND EVALUATION OF
THE PLASTER
MODELS OF
THE JAWS

5. CHECKING THE
DENTURE
DESIGN ON MODELS AND
EVALUATION OF THE
PLASTER
MODELS OF THE JAWS

6. 01
02
The model should be an exact copy of the tissue of the prosthetic
bed, made of solid plaster (Supergypsum)
Draw
-neutral line (on the outer slope of the neutral zone)
-alveolar line (strictly in the middle of the alveolar
process crest)
-median line (in accordance with the mark of the
doctor or with bridles of the upper and lower lips,
bone suture in the anterior part of the hard palate
and blind holes in the posterior part)
on gypsum model

7. CHECK OF THE
DENTURE
CONSTRUCTION IN THE
OCCLUDER OR IN THE
ARTICULATOR

8.  When constructing a denture, it's essential to ensure that the occlusion, or the way the upper
and lower teeth come together, is properly aligned. This is crucial for the denture to function
effectively and provide a comfortable bite for the patient.
 To check the denture construction in the occluder or articulator, the dentist will use a
specialized instrument called an occlusal rim or bite registration. This is a custom-made
device that helps simulate the patient's bite and jaw movements.
 The dentist will place the occlusal rim in the patient's mouth and ask them to bite down or
move their jaw in different positions. This allows the dentist to evaluate how the upper and
lower teeth come together and assess the fit and stability of the denture.
 The occlusal rim helps determine the appropriate positioning and alignment of the teeth on
the denture. The dentist will make any necessary adjustments to ensure that the denture
provides an even and balanced bite.
 Alternatively, an articulator may be used to simulate the movement and position of the
patient's jaws. An articulator is a mechanical device that replicates the jaw movements and
allows for the accurate mounting of the denture on it. This enables the dentist to assess the
occlusion and make any necessary corrections.
 By checking the denture construction in either the occluder or articulator, the dentist can
verify the proper alignment of the teeth, adjust the occlusion if needed, and ensure that the
denture functions well for the patient.

10. INSPECTION OF THE WAX DENTURE CONSTRUCTION IN
THE ORAL CAVITY Fit and Stability:
The dentist will assess how well the denture
fits against the patient's gums and oral
tissues. It should have a snug but
comfortable fit to ensure stability and prevent
any movement or discomfort while speaking
or eating.
Bite Alignment:
The dentist will carefully observe how the
upper and lower teeth come together when
the patient bites down. They will check for
proper alignment, ensuring that the denture
allows for an even distribution of biting forces
and a balanced occlusion.
Speech and Function:
The dentist will assess the patient's ability to
speak clearly and comfortably with the
denture in place. They will also evaluate the
functionality of the denture, checking if the
patient can bite, chew, and swallow without
any difficulties
Aesthetics:
The dentist will evaluate the appearance of
the denture, making sure that it provides a
natural and pleasing smile. They will consider
the size, shape, and alignment of the teeth,
as well as the overall harmony with the
patient's facial features
When it comes to inspecting the wax denture construction in the oral
cavity, it involves a careful assessment of the wax model of the
denture while it is placed in the patient's mouth. This stage is crucial to
ensure that the denture fits properly, provides optimal function, and
meets the patient's aesthetic expectations.
During this inspection, the dentist will place the wax denture in the
patient's mouth, allowing them to evaluate its fit and appearance. The
dentist will examine several key aspects to ensure the correctness of
the construction:
If any adjustments or corrections are needed during this inspection,
the dentist will make note of them and communicate with the dental
laboratory to ensure they are addressed. The dental technicians will
modify the wax model accordingly, incorporating the necessary
changes to achieve an optimal fit and appearance.
Regular communication between the dentist and dental laboratory is
crucial during this stage to achieve the desired outcome for the patient.
The inspection of the wax denture construction in the oral cavity
allows for any necessary modifications to be made before proceeding
to the final fabrication stage.

11. ERRORS OF DETERMINING
THE CENTRAL RELATION OF
THE JAWS STEP

12. When discussing vertical changes in the height of the lower part of
the face, it refers to alterations in the vertical dimension, which
involves increasing or decreasing the distance between certain
reference points on the face.
If there is an error in determining the central ratio, it typically relates
to the alignment or positioning of the central incisors in relation to
the patient's facial midline. This error may affect the overall aesthetic
appearance of the smile, but it is not directly related to vertical
changes in the height of the lower part of the face.
Vertical changes in the height of the lower part of the face are more
commonly influenced by factors such as tooth eruption, loss, wear,
the position of the jaw, or intentional therapeutic or cosmetic
interventions.
If there are concerns about the vertical dimension of the lower part
of your face or the central ratio, it is best to consult with a qualified
dental professional. They will be able to assess your specific
situation, evaluate the underlying dental and facial structures, and
provide appropriate guidance and treatment options to address your
concerns.
ERRORS
"VERTICAL"

13. “INCREASING”
CLINICAL FEATURES:
THE PATIENT'S FACE LIKE "
SURPRISED",
► Nasal labial folds ar flattened,
► THERE IS NO DISTANCE
BETWEEN TEETH (2-3MM) IN
THE STATE OF RELATIVE
PHYSIOLOGICAL REST,
► KNOCKING TEETH IN SPEAKING
SOLUTION:
► IF THE ERROR WAS DUE TO THE
LOWER
BITE WAX RIM YOU NEED TO: to remove
teeth to make a new bite wax rim, to
determine again HLPF and central relation.
► IF THE ERROR WAS DUE TO THE
UPPER WAX RIM, THEN: to make new
occlusal rims, to determine again HLPF
and central relation.

14. “DECREASING”
CLINICAL FEATURES:
SYMPTOM " EXCESS OF SOFT
TISSUES
► NASOLABIAL FOLDS ARE
EXPRESSED
► THE DISTANCE BETWEEN THE
TEETH IN THE STATE OF RELATIVE
PHYSIOLOGICAL REST IS
INCREASED
SOLUTION:
IF THE ERROR WAS DUE TO THE LOWER
BITE RIM,
THEN:
you needed to put the basic wax to the lower
dentition,
determine again HLPF and central relation
► IF AN ERROR WAS HAPPENED OF THE
UPPER RIM,
THEN:
make new bite wax rims,
determine again HLPF and central relation

15. ERRORS
ON
TRANSVERSALS

16. ON "TRANSVERSE" (LEFT OR RIGHT LATERAL
OCCLUSIONS)
► THERE IS “CUSP CUSP”
CONTACT BETWEEN LATERAL
TEETH ON THE BALANCING SIDE
► INCREASE the HLPF
► THE DISPLACEMENT OF THE
LOWER INCISORS MIDLINE
► THE GAP BETWEEN LATERAL
TEETH ON THE SIDE OF THE
DISPLACEMENT (WORKING SIDE)
CLINICAL FEATURES
► TO MAKE A NEW WAX BITE RIM
TO THE LOWER JAW,
► DETERMINE THE NEW CENTRAL
RELATIONSHIP.
SOLUTION

17. ERRORS
"ON
SAGITTALS"

18. WITH FIXED FRONT OCCLUSION
► RELATIONSHIP OF ARTIFICIAL
TEETH BY PROGNATIC TYPE
► THERE IS “CUSP CUSP” CONTACT
BETWEEN LATERAL TEETH
► THE GAP BETWEEN INCISORS
► INCREASE the HLPF
CLINICAL FEATURES
-REMOVE THE LATERAL TEETH
FROM THE LOWER WAX
DENTURE
-TO MAKE A NEW WAX RIM IN
LATERAL DEPARTMENTS,
-DETERMINE THE CENTRAL
RELATIONSHIP.
SOLUTION

19. WITH FIXED REAR OCCLUSION
► RELATION OF ARTIFICIAL TEETH
BY PROGENIC
TYPE
► THERE IS “CUSP CUSP” CONTACT
BETWEEN
LATERAL TEETH
► THE GAP BETWEEN INCISORS
(sometimes)
► INCREASE the HLPF
CLINICAL FEATURES
► TO MAKE A NEW WAX BITE RIM
TO THE LOWER
JAW,
► DETERMINE THE NEW CENTRAL
RELATIONSHIP
SOLUTION

20. ERRORS CAUSED BY
RELEASING
OR SLIGHT APPLICATION OF
OCCLUSAL RIMS TO A
PROSTHETIC
BED (MODEL)

21. NO CONTACT BETWEEN LATERAL
TEETH ON ONE OR BOTH SIDES
DETERMINED
CLINICAL FEATURES
► INSERTING OF THE WAX PLATE
BETWEEN THE NON CONTACT
LATERAL TEETH,
► DETERMINE THE CENTRAL
RELATIONSHIP.
SOLUTION

22. ERRORS CAUSED BY
CRUSHING
THE BITE WAX RIMS

23. ► INCREASE the HLPF WITH
UNEQUAL AND UNCERTAIN CUSP
CONTACT OF LATERAL TEETH
► THE GAP BETWEEN INCISORS
CLINICAL FEATURES
► Make new wax bite rims (if
necessary with a hard basis),
► Determine the central
relationship.
SOLUTION

24. ERRORS CAUSED BY
THE
DISPLACEMENT OF
ONE OF THE BITE WAX
RIM

25. CLINICAL FEATURES:
► Similar to horizontal displacements
CAUSE
► Because of cutting atrophy of bone
base of jaws
SOLUTION:
► Make new wax bite rims with
hard
basis,
► Determine the central
relationship.

26. Ways to eliminate errors
Clinical Try-In: During the clinical
try-in stage, the patient should try on
the wax model of the denture. This
allows the dentist to evaluate the fit,
esthetics, and functionality of the
denture design. Any errors or
discrepancies can be identified and
addressed promptly.
Thorough Communication:
Effective communication between the
dentist and the dental laboratory is
essential. Clear and detailed
instructions should be provided,
highlighting the specific requirements
for the denture design. Any concerns
or expectations should be discussed
and documented to avoid potential
errors.
Comprehensive Patient
Assessment: A thorough
examination and assessment of
the patient's oral condition,
including the anatomy, bite, and
esthetic considerations, should be
conducted. This will help identify
any potential challenges or specific
requirements for the denture
design.
Accurate Impressions: Precise
impressions of the patient's oral
structures are crucial. Ensuring
accurate and detailed impressions
will provide the dental laboratory
with the necessary information to
create a well-fitting and functional
denture.
Attention to Detail: Paying close
attention to the smallest details is
crucial in denture design. This
includes assessing bite alignment,
tooth position, esthetics, and the
overall fit of the denture. Thoroughly
reviewing each aspect of the design
before finalization helps eliminate
errors.
Collaboration with Dental
Laboratory: Establishing a
strong working relationship with
the dental laboratory is vital.
Regular communication, sharing
of information, and feedback
exchanges will help minimize
errors and ensure that the
denture design meets the
desired specifications.

27. THANK YOU