Wax Try-In for Dentures

The wax try-in is a crucial step in the denture fabrication process, ensuring the denture fits harmoniously with the anatomical structure and function of the oral cavity.

1. Checking the Wax Denture on the Articulator:

• a. Position of the Wax Denture on the Articulator:

• Check for contact between the wax denture and the fossae, ensuring the harmonious arrangement of the teeth and the Spee curve.

• b. Checking for Balance During Protrusion:

• Examine the balance of the wax denture when the jaw is protruded, verifying the Spee curve and the cusp angles align with the condylar guidance and incisal guidance.

2. Checking Occlusal Balance During Protrusion:

• a. During Protrusion:

• The Spee curve and cusp angles should align with the condylar guidance and incisal guidance.

• b. At the Incisal Contact:

• All posterior teeth should make contact.

3. Try-In of the Denture in the Mouth:

• a. Checking the Denture Base Border:

• Inspect the denture base border, releasing the border at the labial and buccal frena.

• C. Chin and Tongue: Place a finger on the occlusal surface of the denture, gently pull the lips and cheeks with the other hand to assess denture movement. The denture extension towards the tongue is checked by asking the patient to protrude their tongue. The mandible moves due to pressure from the genioglossus muscle and the posterior part of the tongue.

• E. Posterior: Move the tongue laterally to assess the denture border in the region of the mylohyoid muscle and sublingual gland. The border of the denture anterior to the palatal vault is controlled by the vibrating line.

• b. Checking Vertical Dimension:

• Re-measure the vertical dimension.

• A. Aesthetics: Aesthetics are crucial when evaluating the vertical dimension.

• C. Phonetic Testing: The vertical dimension is assessed through phonetic tests such as “s, j, m, D”.

• c. Evaluating the Occlusal Plane:

• A. Occlusal Plane When Smiling: Assess the occlusal plane when the patient smiles, observing the relationship between the occlusal plane and the retromolar triangle (the occlusal plane should be level with the anterior 2/3 of the retromolar triangle).

• B. Posterior Upper Teeth Too Low: The dentures appear to fall out of the mouth.

• C. Tongue Stability: To stabilize the tongue, it should rest on the occlusal surface of the posterior teeth.

• D. Inclination of the Occlusal Plane: The inclination of the occlusal plane is a key element of balanced occlusion.

• d. Checking Lip Support:

• For good lip support, the denture should be positioned anterior to the alveolar ridge crest but not beyond the labial papillae by 6-8mm.

• e. Checking the Smile Line:

• A. Incisal Edges of the Upper Anterior Teeth: When smiling, the incisal edges of the upper anterior teeth align with the curve of the lower lip. A reversed curve creates a negative aesthetic.

• B. Tip of the Lower Canine and Buccal Cusp of the Lower 4th Molar: Should be level with the lower lip margin, neither lower nor higher.

• f. Checking the Buccal Corridor:

• A. Shape and Position of the Dental Arch: Creates the buccal corridor.

• B. Aesthetics: The buccal corridor contributes to the patient’s aesthetics.

• C. Space: The buccal corridor is the space between the buccal surface of the upper teeth and the corner of the mouth.

• g. Posterior Teeth Balanced Between Buccal and Lingual:

• Lack of buccal contact allows food to escape.

• Positioning teeth excessively towards the tongue limits tongue mobility.

• h. Checking the Relationship of the Centerline and Occlusion:

• Re-check the vertical dimension.

• Re-assess pronunciation with the prosthesis in place.

4. Re-checking Vertical Dimension:

• Instruct the patient to relax their mandible into a resting position, then check:

• Overjet and overbite.

• Re-determine the vertical dimension.

• Re-evaluate the midline relationship.

5. Re-checking Pronunciation with the Prosthesis in Place:

• A. Pronounce “fe,ve”: The incisal edge of the upper anterior teeth contacts the muco-cutaneous junction of the lower lip.

• B. Pronounce “se,je”: The lower anterior teeth nearly touch the opposing upper anterior teeth.

• C. Pronounce “le,fe”: The teeth should not touch; if they do, the vertical dimension is too high.

Note:

• The wax try-in should be performed by a qualified dentist.

• The try-in procedure may need to be repeated multiple times to achieve the optimal result.

• Patients should collaborate with the dentist throughout the try-in process to ensure the best possible outcome.