CD Lec 11 - Reline,Rebase,Repair 2023 RAS_.pdf

Relines, Rebases, Repairs Ronni A Schnell, DMD, MAGD, FICD, FACD RS522 ~ 10/25/23 RELINES Replacement of the inner 1mm of the denture base REBASES Replacement of the entire denture base, saving only the teeth Reline or Rebase of the Complete Denture When? Ill fitting due to: • Ridge and tissu...

Relines, Rebases, Repairs Ronni A Schnell, DMD, MAGD, FICD, FACD RS522 ~ 10/25/23 RELINES Replacement of the inner 1mm of the denture base REBASES Replacement of the entire denture base, saving only the teeth Reline or Rebase of the Complete Denture When? Ill fitting due to: • Ridge and tissue changes... • Healing extraction sites • Age of denture (physiologic changes pt) Clinically, the steps to perform both a reline and a rebase are the same. What differs, are the laboratory steps and the outcomes Evaluation of the Denture • Check age of the denture – Lifespan of a denture 7-10 years,,, – See materials list • Eval contours of the denture: – If acceptable: – RELINE Immediate denture Interim denture Complete Denture • vs If not acceptable… REBASE Immediate or Interim Denture Older complete denture Porosities (lab error) Shade (clinician or lab error) Midline fracture Assessment of VDO – Maintain VDO? – Increase VDO? • Check occlusion – Adjust CO=CR to establish a stable occlusion prior to impressioning Assessment of VDO You must decide prior to final reline/rebase impression whether the VDO will be maintained or increased  Maintain if the VDO is still acceptable.  Increase if the occlusion shows signs of wear and loss of vertical, but is still serviceable. The increase will be 1-2 mm maximum. If >2mm needed, or the occlusal table severely worn, remake denture. Check Occlusion Adjust CO=CR to establish a stable occlusion Then seat the impression for reline or rebase in this occlusion * * Please know that you will be doing an occlusal adjustment at insertion, as well Each time border molding is added or the final impression is placed… a FUNCTIONAL impression technique MUST be used. This is also known as a CLOSED MOUTH POSITION and is required In preparation for the reline or rebase impression… Reduce denture borders by about 2-3mm to allow for border molding material Peel out as much soft liner first then… Remove any tissue conditioner or old reline material and freshen up the denture base for mechanical adhesion To MAINTAIN VDO for a reline or rebase of a complete denture Reduce all interior acrylic by ~1.5 mm (to make room for final impression material) except for 3 tissue stops at the CURRENT VDO. Use Boley gauge. Location of tissue stops: One in Anterior-but not on incisive papilla and Two in Posterior-anterior to tuberosities (U) or retromolar pads (L) To MAINTAIN VDO Tissue stop cut away and offset from incisive papilla and tuberosities ~ 1.5 mm To INCREASE VDO Add grey or green compound tissue stops to the appropriate vertical. Maximum 1-2 mm. Once vertical has been established, next reduce borders of ‘tray’. Treat the patient’s existing denture like a custom tray… …border mold functionally (in occlusion), place compatible adhesive and let it cure before taking impression. During border moulding and final impressioning, ensure patient closes and stays in function (in occlusion) throughout the set For patients who have a difficult time remaining in CR during set you can have them bite into a pre-rehersed & set CR record for the duration Evaluate the reline impression the same way as you would evaluate a final impression Make the final impression using a mucostatic impression material such as light bodied rubber base. After the impression is set, trim flash and reseat in order to take CR bite with Aluwax to orient denture Small well circumscribed voids with sharp margins can be filled with disclosing wax Outline of Post dam drawn on impression because cast does not yet exist Mechanical post dam technique. Compressive tissue depths documented in record so cast can be scored after flasking Bead, box and pour… …but DO NOT SEPARATE!! Because vertical has not yet been secured What holds VDO? Clinic Lab – Jig reline Lab-Flask Reline Articulator Jig Flask Pin Levelling screw And of Flask • Both flask and jig require an occlusal index General Summary of Reline/Rebase • • • • • • Check & correct occlusion Check & correct borders Place tissue stops, relieve intaglio of denture, if maintaining VDO Border mold and final impression functionally (in occlusion) Record Post Dam Re-check the occlusion and take CR @ VDO Analog: • Bead, box & pour impression – DO NOT SEPARATE until occlusal index is made • Process Digital: • Scan intaglio, cameo, opposing & CR • If previous digital - keep all previous data, replace intaglio scan file • If new digital - Digital preview & approve • Mill final denture INSERTION: Insert denture and adjust (intaglio, borders & occlusion) including clinical remount Detailed Summary of Reline/Rebase Clinical Technique Handout In today’s folder on Blackboard And in RS532 RS642 Relines Rebases Repairs Replacing teeth or portions of denture base Replacement of a Fractured or Lost Tooth Tooth selected is same size or larger Residual portion of broken tooth is ground away taking care not to perforate denture base Tooth is luted on facial with sticky wax Space is created on lingual for repair acrylic Repair acrylic Using “salt and pepper” technique (liquid / powder) 20 lb psi for 20 min Repair site Incipient Midline Fracture Craze line was discovered in overdenture at first denture recall Weak repair site which is liable to re-fracture and is an indication for a Rebase Prepare and bevel repair site Add horizontal barbell perpendicular to fracture on polished facial side. Prepare and bevel repair site Add horizontal barbell perpendicular to fracture on polished palatal side. Repair site is NOT widened on intaglio side. Reinforcement pin used to stabilize site Pin or metal mesh reinforcement placed in groove prior to acrylic placement Facial repair site Palatal repair site Assessment of the Problem • Why did this midline fracture occur? • Did the patient drop the denture? • Is the immediate denture fulcruming off the intaglio surface of the remodeled ridge after resorption? • Is there an occlusal reason? • Assessment is critical in order to apply appropriate corrective procedure • Should there be a follow up procedure? Denture Base Fracture at Overlay Abutment Site Be sure to check occlusion and proper height of abutments before addressing the repair Very Common A clean fracture – means the two haves fit back together perfectly Repositioning of parts bench side. Splinted on temporary cast with tongue blade & sticky wax Temporary repair cast can be made of dental stone or silicone putty Pressure-cured repair of midline fracture 20 lb psi for 20 min Notice cross arch stabilization with sticky wax and heavy gauge wire Repair site Overdenture repair site likely to re-fracture & will need a Rebase as a follow-up for definitive treatment Incipient or Complete Midline Fracture Always follow up this weak repair site which is liable to re-fracture with a Rebase We repair it only in order to take a final impression for the Rebase Fractured Denture Border Non-occlusal bearing load Missing border replaced w/ Compound intra-orally Block out undercuts; Cast poured to support denture & repair site Compound removed from denture & denture re-seated Repair acrylic to be added here Repair acrylic Repair acrylic in repair site Repair site after curing @ 20 psi for 20 min Border likely to re-fracture? No Post Dam Augmentation Indicated when all other aspects of denture are acceptable but denture lacks retention due to insufficient post dam Compound added intra-orally and functionally* to postdam area and to distobuccal areas bilaterally. * assessing immediate improved retention Repair cast created Compound removed & denture reseated Note: gap now between denture and repair cast 20 lb psi for 20 min Repair acrylic added & denture re-seated Pressure cured 20 lb psi for 20 min Intaglio surface not polished for cohesion Ex of Repairs of Malpositioned Tooth Set-ups Chief Concern Problem Repair Whistle-pathognomonic Maxillary teeth set too far lingually (offset correct with mandibular teeth) Reset upper teeth; lower may or may not require reset depending on offset/ crossbite Lisp-pathognomonic “so” sounds like “show” Maxillary teeth set too far buccally (offset correct with mandibular teeth) Add wax to linguals of upper denture teeth process Cheek biting Tongue biting Maxillary teeth and mandibular teeth set edge to edge regardless of B/L position on ridge Reset upper or lower posteriors as appropriate e.g if monoplane lower set to crest of ridge, then reset monoplane upper posterior teeth with correct offset T sounds like D Maxillary anterior teeth too lingual Reset upper and/or lower as appropriate incorporating all equally critical factors (overlap, over-jet, lower crest of ridge, upper incisive papilla, lip support) D sounds like T Maxillary anterior teeth too labial Ex of Repairs of Malpositioned Tooth Set-ups Chief Concern Problem Repair Whistle-pathognomonic Maxillary teeth set too far lingually (offset correct with mandibular teeth) Reset upper teeth; lower may or may not require reset depending on offset/ crossbite Lisp-pathognomonic “so” sounds like “show” Maxillary teeth set too far buccally (offset correct with mandibular teeth) Add wax to linguals of upper denture teeth process Cheek biting Tongue biting Maxillary teeth and mandibular teeth set edge to edge regardless of B/L position on ridge Reset upper or lower posteriors as appropriate e.g if monoplane lower set to crest of ridge, then reset monoplane upper posterior teeth with correct offset T sounds like D Maxillary anterior teeth too lingual Reset upper and/or lower as appropriate incorporating all equally critical factors (overlap, over-jet, lower crest of ridge, upper incisive papilla, lip support) D sounds like T Maxillary anterior teeth too labial Most repairs require an impression called: The “Pick-Up” Impression an impression that incorporates a prosthesis, framework, copings, or attachments for the purpose of making a cast as a relationship record within the arch GPT v9 Adding teeth and a denture base Depending on the repair, you must first create a cast with the denture in place. A pick-up impression technique is utilized. Pouring the cast with the prosthesis still embedded in the alginate produces a cast with a precise fit. DO NOT attempt to seat the prosthesis on a cast made without a pickup Cast made from pick up impression The specific procedures being done here are  to reduce the 2 remaining teeth to just above the gingival margin,  add coverage to the retromolar pads  and convert this provisional to an interim overlay denture Occlusion or not? Required Steps Reline Rebase Repair Impression Yes Yes +/- Bite Yes Yes +/- If the denture has an occlusion, then YES! You need to orient the prosthesis back to the patient's dentition When in doubt, take a bite anyway! The Assessment When a denture requires a reline, rebase, repair, we need to ask specific questions and determine confounding factors, in order to select both the appropriate procedure and material. 1. 2. 3. 4. 5. How old is the denture? How old is the liner (if any)? How did the break/damage occur? Evaluate the occlusion. How long does the solution need to last? (Length of service) Materials List One of the most critical questions to answer in the decision-making process whether to reline or rebase, is regarding length of service of the denture. The length of service needed is a function of the lifespan of the prosthesis Length of service 1 week 1 month 1 year 1 year 3 years 7 years Consistency Type of cure super-soft self-cured soft self-cured soft pressure-cured hard self-cured hard pressure-cured hard heat-cured Procedure reline reline reline reline reline rebase What to use? Diagnosis - What is the problem? Duration - How long must the solution last? How long will the prosthesis last? = Conventional Milled printed Injection molded Conventional Milled printed Injection molded Plasticizer A substance added to a synthetic resin to produce or promote plasticity and flexibility and to reduce brittleness Conventional Milled printed Injection molded Self cure therefore require catalysts Conventional Milled printed Injection molded Conventional Milled printed Injection molded JIG Flask Conventional Flask Flask Milled printed Injection molded Conventional Milled printed Injection molded ReCap • What is the problem? • How long does the patient need the solution to last? Clinical Scenario #1 What would you do for 5 year old denture that needs a reline if you know the average denture lasts about 7 years? Conventional Milled printed Injection molded Clinical Scenario #2 What would you do if a brand new denture fractures from a fall? Repair first, then immediately… Rebase! Conventional Milled printed Injection molded Conventional Milled printed Injection molded 1 1 Super-soft and soft reline materials are more porous than hard reline materials. 2 2 Conditioners temper the heat of the reaction to MMA. 3 Catalysts activate the reaction. 1 3 4A Silicone does not contain plasticizers and due to the lower degree of cross-linking compared with their heat activated counterparts, they cannot survive long term. 4B Plasticizers decrease water sorption and solubility, thereby promoting denture liner stability; as they leach out liner hardens. 4A 4B 5 5 MMA methylmethacrylate Conventional Milled printed 6 MMA allergy change method IvoBase 7 EMA Ethylmethacrylate Possible allergen Indirect resin build-up 6Injection molded Eclipse 7 EMA Milled and Printed Dentures Milled pucks: Pre-polymerized PMMANegligible free monomer May be repaired/relined Printed material: Urethane methacrylate May be repaired/relined with a bonding agent Flexible Partial Dentures • Thermoplastic nylon resin… may not be repaired CD2 Exam • From Tooth Selection & Esthetics lecture through today • SLC material and videos • 50-55 questions – – – – – Multiple choice Multiple answer True/False ~5 photo attached questions Clinical scenarios/significance • Focus on the WHY- when the WHY is clear, the HOW is easy! » Do not just memorize the slides » Critically think the scenarios