Tooth Setting (5)
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Transcript of Tooth Setting (5)
ARRANGEMENT OF ARTIFICIAL TEETH
Aims of Arrangement
1. Preservation of alveolar bone2. Esthetics3. Masticatory efficiency4. Retention and stability during function5. Health and comfort of the TMJ
Factors Affecting Position of Teeth
1. Esthetics• Lip support• Tooth visibility• Buccal corridor
2. Function • Speech and mastication
3. Stability• Neutral zone
Guides to Positioning Anterior Teeth
Payne stated,“Set the teeth where they grew.”
However,• patient may not want the original tooth
position and arrangement• an esthetically correct position may be
functionally unstable
Preextraction Guide
• Photographs• Cast
Postextraction Guides
Anteroposterior position Supeoinferior position
Visibility of upper incisors Mediolateral position
- Midline of face- Ala of nose
Inclination or slant
Anteroposterior Position
• Distance from the incisive papilla– 8-10mm
• Relation to the residual ridge– Anterior to the ridge
• Fullness of lips (esthetics as guide)• Phonetics as guide
Phonetics
• Labial sounds• Labiodental sounds• Dental and alveolar sounds• Palatal and velar sounds
Labial Sounds
• b, p, m• Insufficient lip support can cause these sounds
to be defective
Labiodental Sounds
• f, v• If the upper anterior teeth are too short, the v
sound will be more like an f• If they are too long, the f will sound more like
a v
Dental Sounds
• th• Tip of tongue extends slightly between the
upper and lower teeth• About 3mm of the tongue should be visible
Alveolar Sounds
• t, d, n, s, z• Contact between the tip of the tongue and
the alveolus or the lingual side of the anterior teeth
• If teeth are too lingual, t will sound like d• If too anterior, d will sound like t
Sibilants
• S, z, sh, zh, ch, and j• Upper and lower teeth should approach but
not touch
Inclination of the anterior teeth.
• Relationship to the labial plate – The roots of anterior teeth are parallel to and
close to the labial surface of the bone.– The cervical third of teeth appear to be
continuous with the labial plate of bone.
• Relationship to the facial profile– Teeth are inclined parallel to the lower third of
the face.
Relationship to the labial plate
Relationship to the facial profile
Arrangement of Posterior Teeth
Guides to Positioning Posterior Teeth
Both upper and lower posterior teeth are centered over the crest of the ridge whenever possible. This improves the balance and stability of the denture.
Guides to Positioning Posterior Teeth
Don’t place teeth too far buccally as it can cause:
1. Cheek biting2. Denture instability3. Esthetic problems
Guides to Positioning Posterior Teeth
Placing the teeth too lingually can cause:1. Crowding of the tongue2. Tongue biting3. Imbalance due to tongue function
Approaches to Posterior Setting
1. Setting all the maxillary teeth first2. Setting all the mandibular teeth first3. Setting the mandibular teeth before the
corresponding maxillary teeth
Maxillary should not be placed over the maxillary tuberosity as it can cause lever imbalance.
Mandibular teeth should not be placed over the retromolar pad or on the slope as it can result in denture sliding and instability.
Occlusal Schemes in CD
A. Balanced OcclusionB. Non-balanced OcclusionC. Lingualized OcclusionD. Functionally generated occlusal scheme
Christensen’s Phenomenon
• Separation of the posterior teeth caused by the downward movement of the condyle during mandibular protrusion and lateral movement (balancing side)
Balanced Occlusion
• Bilateral, simultaneous, anterior and posterior occlusal contact of teeth in centric and eccentric positions
Balanced Occlusion
• Ideal occlusal scheme for CD• Achieved by incorporating compensating
curves into the posterior setting
Compensating Curves
• are artificial curves introduced into the CD occlusion in order to achieve a balanced occlusion
Compensating Curves
Curve of Spee - an anteroposterior curve along the cusp tips and incisal edges of teeth
Curve of Wilson - a mediolateral or side-to-side curve contacting the cusp tips of posterior teeth
Advantages of Balanced Occlusion
1. Improves stability and retention of the denture bases
2. Reduces soreness and resorption caused by the denture base movement
3. More comfortable to the px
Non-balanced Occlusion
• No attempt is made to create balanced occlusion. Creating multiple uniform contact in centric relation was sufficient
Lingualized Occlusion
• Forces are directed towards the lingual side• It was claimed that this improved the stability
of the lower denture