it may be used by dental students

1. Orthopedic dentistry
Topic 3 and 4

2. Articulation:
• Articulation in speech involves the precise coordination of various
articulatory organs. This process includes the placement of the
tongue, lips, and the opening or closing of the vocal cords to
produce specific speech sounds or phonemes. It is a complex
process that varies across languages and dialects.

3. Occlusion and Its Types:
• - Class I Occlusion (Neutrocclusion)
•- Class II Occlusion (Distocclusion)
•- Class III Occlusion (Mesiocclusion)

4. Class I Occlusion (Neutrocclusion):
• This is considered normal occlusion, where the upper teeth
slightly overlap the lower teeth when the jaws are closed, and the
molars fit together correctly.

5. - Class II Occlusion (Distocclusion):
• In Class II, the upper teeth significantly overlap the lower teeth,
resulting in an overbite. This is further divided into Class II division
1 and division 2 based on specific characteristics.

6. - Class III Occlusion (Mesiocclusion):
• Class III occlusion presents as an underbite, where the lower teeth
protrude ahead of the upper teeth when the jaws are closed.

7. Physiological Types of Occlusion:
• Angle's classification system categorizes occlusion into various
classes based on the relationship of the first molars. Class I is
characterized by the mesiobuccal cusp of the upper first molar
aligning with the buccal groove of the lower first molar, while
Class II and Class III describe discrepancies in this alignment.

8. Anatomical Structure of the
Temporomandibular Joint (TMJ):
• The TMJ is composed of the temporal bone (part of the skull), the
mandible (lower jaw), and an articular disc. This joint is essential
for various jaw movements, including opening, closing, and side-
to-side motions. It is highly adaptable and sensitive to any issues,
often causing discomfort when not functioning correctly.

9. Biomechanics of the Lower Jaw:
• The lower jaw's biomechanics are complex, involving various
muscles, ligaments, and joints. The TMJ plays a pivotal role in the
lower jaw's mobility. The jaw's movements, such as rotation and
translation, are influenced by forces applied by these structures
and the positioning of the teeth.

10. Concept of Stabilization of Prostheses:
• Stabilization of prostheses, like dentures, is crucial to ensure their
functionality and patient comfort. It involves designing the
prosthesis to fit securely within the oral cavity, preventing
unwanted movement during activities like eating or speaking.

11. Factors of Stabilization:
• Factors impacting the stability of prostheses include the fit and
quality of the prosthesis, the underlying oral tissues (gums and
bone), and the use of adhesives or attachments to enhance
retention. Properly fitted prostheses contribute to the stability
and function of the oral prosthesis.

12. Hanau-Bonville's Laws of Articulation:
• These principles in prosthodontics, developed by George Hanau
and Wilfred Bonwill, guide the arrangement of artificial teeth on
dentures to mimic the natural occlusion and provide optimal
function. These laws help in creating a balanced occlusion and
include the curve of Spee, curve of Wilson, and the compensating
curve, which consider factors like cuspal inclinations and tooth
contact patterns for proper articulation.

13. Method for Determining Central Occlusion and
Central Jaw Ratio:
• 1. Central Occlusion: Central occlusion, also known as centric
occlusion or centric relation, is the position where the upper and lower
teeth fit together correctly and comfortably. Dentists use various
methods, including the "gothic arch tracing" and "leaf gauges," to
determine and record a patient's central occlusion.
• 2. Central Jaw Ratio: The central jaw ratio is a proportion
that indicates the relationship between the maxilla (upper jaw) and
mandible (lower jaw). This ratio is essential for proper occlusion and can
be assessed through various diagnostic techniques, such as
cephalometric analysis and dental models.

14. Fixation of Dentition in Central Occlusion Using
Occlusion Registers:
• Occlusion registers, often made from wax or silicone material, are used
to record and maintain the central occlusion of a patient. The steps
involved in this process include:
• 1. Preparation
• 2. Record the Central Occlusion
• 3. Check and Adjust
• 4. Curing or Solidification
• 5. Final Verification

15. • 1. Preparation: Ensure that the patient is relaxed and in a
stable position, which usually involves using a semi-adjustable dental
chair. The dental chair can be adjusted to allow the patient to sit
comfortably.
• 2. Record the Central Occlusion: Place the occlusion
register, which is typically a soft, deformable material, between the
upper and lower teeth in the central occlusion position. Ask the patient
to bite down gently but firmly to create an impression of their central
occlusion.

16. • 3. Check and Adjust: Examine the occlusion register for accuracy. It
should capture the central occlusion precisely. Make any necessary adjustments
to ensure a proper fit.
• 4. Curing or Solidification: If using a material like silicone, it
might need to be set or solidified according to the manufacturer's instructions.
• 5. Final Verification: Once the occlusion register is prepared and
properly set, it can be used to verify and reproduce the central occlusion for
various dental procedures.

17. Devices That Reproduce the Movements of the
Lower Jaw - Occluders and Articulators:
• 1. Occluders: Occluders are dental instruments designed to assess and
adjust the occlusion of the teeth. They can be used to check how the upper and
lower teeth come together and to make precise adjustments. Occluders often
have adjustable components that simulate jaw movement.
• 2. Articulators: Articulators are devices that replicate the movements
of the lower jaw and the spatial relationships between the upper and lower
teeth. They come in various types, from simple hinge articulators to fully
adjustable semi-adjustable articulators. Dentists use articulators to analyze a
patient's bite and perform procedures like setting dentures or creating crowns
and bridges.

18. Principle of Working with Them:
• The principle of working with occluders and articulators involves the following
steps:
• 1. Mounting Models
• 2. Analysis
• 3. Treatment Planning
• 4. Adjustments
• 5. Reproducibility
• These devices are crucial in modern dentistry for achieving accurate and
functional results in various dental treatments.

19. • 1. Mounting Models: Dental models, often made from impressions of
the patient's teeth, are mounted on the articulator or occluder. This replicates
the patient's bite.
• 2. Analysis: The dentist or dental technician uses the device to analyze
the patient's occlusion, allowing for precise examination and adjustments.
• 3. Treatment Planning: Based on the analysis, the dentist can plan
treatments such as crown and bridge work, denture fabrication, and
orthodontic adjustments.

20. • 4. Adjustments: These devices allow for fine adjustments to
ensure the patient's bite is accurate and comfortable.
• 5. Reproducibility: The use of articulators and occluders
ensures that dental restorations closely replicate the patient's natural
bite and function.

21. stage of determining central
occlusion and central relationship
in prosthodontics

22. • 1. Imprecise Record Taking: If the dentist does not take precise
impressions and bite registrations, it can lead to errors in the subsequent steps.
Using outdated or poorly maintained equipment can also contribute to
inaccuracies.
• 2. Failure to Account for TMD: Temporomandibular disorders
(TMD) can complicate occlusal determination. Ignoring signs and symptoms of
TMD, such as joint noises or pain, can lead to occlusal problems.
• 3. Neglecting Functional Movements: A patient's occlusion
must consider functional movements like excursive and protrusive movements.
Ignoring these can result in occlusal interferences and discomfort.

23. • 4. Ignoring Skeletal Issues: Dental occlusion should take into
account the patient's skeletal relationship, such as the type of malocclusion.
Neglecting skeletal issues can lead to instability in the occlusion.
• 5. Lack of Proper Training: Dentists who are not adequately
trained in occlusal principles may make errors in diagnosing central occlusion.
Continuing education is essential in this field.
• 6. Inadequate Patient Communication: Failing to
communicate effectively with the patient to understand their concerns and
expectations can result in dissatisfaction with the final restoration.

24. • 7. Inconsistent Record Keeping: Detailed records, including
photographs and radiographs, are essential for accurate occlusal
determination. Inconsistent or incomplete record keeping can lead to
errors.
• 8. Disregarding Posterior Tooth Arrangement: The
arrangement of posterior teeth is crucial for occlusal stability. Neglecting
this aspect can lead to imbalances in the occlusion.
• 9. Inadequate Occlusal Adjustment: Even after restoration,
failing to perform precise occlusal adjustments can result in occlusal
discrepancies and discomfort for the patient.

25. • 10. Not Considering Aging Effects: The occlusion can change
over time due to factors like tooth wear and shifting. Failing to consider
these changes can lead to issues with long-term stability.
• In prosthodontics, achieving an accurate central occlusion and central
relationship is essential for the long-term success and comfort of
restorations. Dentists should be meticulous in their approach, continually
update their knowledge, and collaborate effectively with the dental
laboratory to minimize these potential mistakes.

26. Thanks for your attention