Managing Wear and Esthetics

Transcription

1 Managing Wear and Esthetics KEY Occlusal Dental Components: - Centric contacts - End-to-end contacts - Pathways KEY: In order to increase the predictability in managing patients with wear, it is advisable to try and determine what it is that they are doing to their existing dentition. If you can identify the positions the patient grinds, the occlusion can then be designed accordingly Pathway wear - Wear from centric contact out to end-to-end - Observe facets on: facial surface of mandibular incisors palatal surface of maxillary incisors End-to-end wear - Wear on incisal edges of teeth from end-to-end contact - Observe facets on: "flat incisal edges of mandibular and maxillary incisors Crossover wear - Wear on incisal edges of teeth from contact that occurs when the patient goes beyond end-to-end - Observe facets on: lingual incline of the incisal edges of mandibular incisors facial incline of the incisal edges of maxillary incisors Pathway Wear - When pathway wear in observed, the new guidance should either Follow the same pathway Follow a more shallow pathway - A custom incisal guide table can be used to replicate a patient s existing or accepted Envelope of Function

2 initial presentation showing multiple fractures of veneers 3 months after placement Failure KEY: Single tooth failure most likely represents an occlusal contact Multiple tooth failure most likely represents an envelope of function problem what wear positions does the above patient have? pre-tx model showing pathway facets and edge-to-edge facets KEY: - The teeth are in the way of the patient s path of movement - Pathway wear from ICP to edge-to-edge can be the most destructive pattern of movement to produce fractured porcelain Question: Why not use another material or switch to a crown?

3 KEY: in the anterior, strength is determined by the weakest portion of each restoration (the veneering ceramic), so the choice is based on esthetics PROBLEM: The teeth are in the way of the patient s movement pattern GOAL: To provide a guidance pattern which minimizes any interfering tooth contacts and matches the patient s envelope of function What is the Envelope of Function? Functional Movements of the Mandible Gibbs CH, Messerman T, Reswick JB J Prosthet Dent 1971; 26: Objectives: - Provide an accurate study of jaw movement - Determine the manner and degree that differing states of occlusion affect jaw motion Materials / Methods: - 12 patients (4-normal occlusion, 4-malocclusion, 4-rehabilitated occlusion) Definition: Envelope of Function Dental Envelope of Function The pathway of mandibular movement created by the contours of the teeth Neuromuscular Envelope of Function The pathway of mandibular movement created by the patient s neuromusculature Changes of Masticatory Movement Characteristics After Prosthodontic Rehabilitation of Individuals with Extensive Tooth Wear Ekfeldt A, Karlsson S Int J Prosthodont 1996; 9(6): Material / Methods: - Evaluated 11 patients with extensive tooth wear using graphical tracings of jaw movement - Recalled the patients 3 years after complete dental rehabilitation and graphically traced their jaw movement again Results: - 9 of 11 patients seen at 3-year follow-up - The masticatory cycle adapted to the altered form of the occlusal surfaces

4 - Out of the 9 patients: 2 patients displayed wear and fracture of restorative materials, 1 patient fractured abutment preparations (Total = 33%) KEY when treating patients with wear: 1. Identify the neuromuscular envelope of function - wear - fracture - mobility - fremitus - sensitivity 2. If altering the dental envelope of function, trial therapy must be performed GOAL: Have the dental envelope of function in harmony with the patient s neuromuscular envelope of function Treatment Options - IF the envelope of function is the problem (and the patient likes the new tooth length): Increase the vertical dimension Alter the lower anteriors Trial occlusal therapy must be performed to test the tooth position and guidance... UNLESS you know of a pre-existing envelope of function that works for the patient The use of a custom incisal guide table - Used to mimic the neuromuscular envelope of function that the patient previously had of currently has

5 pre-treatment model compared to model of new veneer restorations KEY: Use the custom incisal guide table to determine how much the anterior relationship will need to be altered custom incisal guide table fabricated from pre-tx models mounted on the articulator Correction of an Envelope of Function Problem 1. To begin treatment...start with the diagnostic waxing - the wax-up is only completed at this point for esthetics (incisal edge position and facial surface) diagnostic wax-up completed for incisal edge position and facial surface 2. To wax the palatal contour (centric contact and pathway) you first need to either open the vertical OR alter the mandibular incisal edge position

6 Open the Vertical Dimension Question: How much do you open the vertical??? Answer: Use the guide table to determine how much KEY: - Undo the condylar housings and bring the models into end-to-end position (this pin will not be toughing the guide table) - With the models in end-to-end, loosen the pin and drop it until it touches the guide table - Re-tighten the pin KEY: This is the new vertical dimension of occlusion - Wax the posterior and anterior dentition to obtain centric contacts - Move the incisal pin on the guide table to wax and carve the pathway from centric contact to incisal edge Alter the mandibular incisal edge position Question: How much do you shorten the mandibular anteriors??? Answer: Use the guide table to determine how much KEY: - Undo the condylar housings and bring the models into end-to-end position (the pin will not be toughing the guide table) - With the models in end-to-end, shorten the lower incisal edges until the pin touches the guide table KEY: This is how much the lower incisors need to be shortened - Wax the palatal of the maxillary anteriors to regain centric contact - Move the incisal pin on the guide table to wax and carve the pathway from the centric contact to the incisal edge How do you determine whether to open the vertical OR alter the lower anteriors? KEY: Evaluate the mandibular occlusal plane

7 IF: the mandibular occlusal plane has a step from anterior to posterior: THEN: alter the lower incisors IF: the mandibular occlusal plane is level: THEN: increase the vertical dimension of occlusion altering the mandibular incisal edge position on the model using the custom incisal guide table prior to completing the diagnostic wax-up provisional trial therapy Custom incisal guide table treatment KEY: Excursive movements into and out of maximum intercuspation created by the patient over years are captured by the guide table and transferred to the restorations - the patient will continue to do what they do - but the new restorative dentistry lives in harmony with that movement definitive restorations at 8 years definitive restorations at 8 years

8 initial presentation multiple fractures / failures of veneer restorations (note: the severe wear of the palatal tooth surface was not present prior to restorations being placed it was created by the dentist adjusting for pathway freedom ) KEY: If the palatal tooth surface was not changed and the porcelain is breaking, altering the palatal concavity will not solve the problem lower anteriors show vertical and horizontal facets indicating the patient has a pathway to edge-to-edge problem KEY: Since the veneers didn t alter the palatal pathway, the key to treatment is that the porcelain is in the way of the patient reaching edge-to-edge position evaluating the lower occlusal plane reveals the lower anteriors are stepped up above the lower posteriors (the key to treatment is the level the lower occlusal plane)

9 Other uses for a Custom Incisal Guide Table Transferring specific occlusal contacts in excursive movements Mimicking the guidance obtained in the trial therapy phase created with provisionals When you notice pathway wear at the examination Clinical findings: - Severe palatal notching of #6-11 causing tooth #10 to fracture - CR CO discrepancy - Restricted envelope of function - Recurrent caries #13,15

10 significant pathway (lack of horizontal facets indicates restricted tooth wear) Question: How do you get room to restore the wear AND how much room do you need? key: with pathway wear, you need to re-create the same pathway or give the patient more freedom, not just replace what has been worn away \ KEY: To provide a guidance pattern which minimizes any interfering tooth contacts usually increased overjet treatment key Treatment Options for a restricted envelope of function: - Open the VDO - Alter the mandibular incisal edge position Question: How do you decide which to do? Answer: Evaluate the mandibular occlusal plane

11 IF: the mandibular occlusal plane has a step from anterior to posterior: THEN: alter the lower incisors IF: the mandibular occlusal plane is level: THEN: increase the vertical dimension of occlusion KEY: - Whenever pathway wear is observed, a custom incisal guide table should be fabricated from the mounted study models to aid in the replication of excursive movements into and away from maximum intercuspation. -The patient s movement pattern can then be replicated when designing the new tooth contours in the diagnostic wax-up treatment is aimed at replicating the patients existing movement pattern (not just replacing what has been worn away) Fabrication of a Custom Incisal Guide Table: - Mount models using Facebow and CR record - Place Triad on the guide table of the articulator Note: may want to cover the table first to protect it - Lubricate guide pin and Triad with dentin adhesive or unfilled resin - Undo the condylar housings and move the articulator through excursive movements (protrusive, lateral, and everywhere in between) Note: The guide pin should move smoothly over the Triad creating an analog of the guidance. If the guide pin drags at all over the Triad, apply more adhesive - Once completed the Triad can be light cured Use of the Custom Incisal Guide Table: - The custom incisal guide table is used to replicate the patients existing movement pattern

12 during the diagnostic wax-up. The contours created in the wax-up are then transferred to the patient s mouth in the provisional phase new crown contour is a replication of the existing neuromuscular envelope of function obtained from the custom incisal guide table CONCEPT: Design the provisionals (and restorations) to allow freedom of movement within the neuromuscular envelope the patient has developed restoration follow-up: 6 years maxillary arch, 3 years mandibular arch

13 End-to-end Wear - Wear on incisal edges of teeth from end-to-end contact - Observe facets on: "flat incisal edges of mandibular and maxillary incisors initial presentation of 23-year old patient who wants to address the anterior tooth wear

14 end-to-end positions showing how wear was created mounted models help identify the various positions the patient moves to create tooth wear (evaluate wear patters and confirm the mandibular positions that created them) treatment process: step 1 treatment process: step 2 KEY: Must create broad incisal contacts that allow multiple areas for even force distribution

15 treatment process: step 3 treatment process: step 4 (options to regain anterior coupling: equilibrate posteriors or add to palatal of maxillary anteriors)

16 completed wax-up and associated putty matrix definitive treatment: direct incisal composite #6-11

17 Crossover wear - Wear on incisal edges of teeth from contact that occurs when the patient goes beyond end-to-end - Observe facets on: lingual incline of the incisal edges of mandibular incisors facial incline of the incisal edges of maxillary incisors mesial incisal edges of maxillary anteriors patient exhibiting wear of maxillary and mandibular incisal edges that do not match up with opposing dentition in traditional movements a crossover pattern of wear reveals how the patient created the facets Question: How do you know if you can alter the patient s pattern of movement? Answer: Try using anterior guidance in plastic to see what the patient s occlusal behaviors will be with an altered occlusion Technique KEY: 1. Fabricate and adjust an appliance 2. Color appliance with a Sharpie marker

18 3. After wearing 3-4 weeks, have patient return to office to observe movement pattern AND check the voluntary range of motion the black marker has been removed by patient s grinding pattern while the marked red areas indicate the patients voluntary range of motion KEY: Following trial therapy make a diagnosis Question: Did the patient continue to grind during trial therapy? If yes..identify the positions the patient grinds and design the occlusion accordingly laterotrusive = 50%, protrusive = 34%, cannot discern = 16%

19 initial presentation: patient desires correction of wear on central incisors left lateral right lateral

20 left-protrusive crossover diagnostic wax-up showing proposed contour changes putty matrix in place (KEY: must have 1mm of material at incisal edge for stuctural integrity) KEY: Place putty matrix and scribe line onto the putty to demarcate the edge of the preparation placement of enamel composite (0.5mm) on the putty outside of the mouth (Note: carry the enamel just past the scribed line)

21 putty matrix is carried to the mouth and seated in place (material is adapted and cured) KEY: Keep the enamel separated interproximally prior to curing dentin build-up in place KEY: - Dentin must be layered to follow mammalons - Dentin should not be placed in a straight line relative to the incisal edge - Must pay attention to the placement of dentin relative to the facial enamel surface (want to have ~1mm of enamel over the dentin) completed build-up prior to finishing / polishing

22 completed restorations

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