Prosthetics Revision Clinical Steps Dr Charles Scola July 2004

Prosthetics Revision Last two weeks we studied:  Dentist / Patient expectations  The value of an old denture  A written denture treatment plan  RVD = OVD + FS  Copy Denture Technique  F/F Clinical techniques  Overdentures

Meeting their needs & expectations  What sort of patient are they?  Easy going or up-tight  Adaptable or precise  Accepting or demanding  Cooperative or difficult  Asses their attitude & personality,  This is very important in denture tolerance  NEVER promise what you cannot deliver !

Your Denture Treatment Plan  This is your written prescription or recipe  Without it you will get lost !  It applies to new or old denture users  Must be agreed with the patient  Keeps you on the right track  Is your record and defense, in case of later problems or complaints

At every stage of treatment  Check your treatment plan  Remind your patient of the plan  Explain what you are doing today  Measure RVD & OVD  Look at the old dentures & compare  Observe the patient as they talk & smile  Remind the patient of the limitations

Vertical Dimension  RVD is always > OVD  RVD should remain constant  whether dentures are worn or not  Whatever treatment you do  OVD may be changed by you  All patients need FS, 2 – 5mm

Vertical Dimension RVD Freeway space

Vertical Dimension 0VD

Prosthetics Revision  Today we are going to consider:  Partial Denture planning & design  The clinical stages of partial denture construction

Please read Dr Ulpee Darbar’s notes, these are very good !

Partial dentures often grow up into full dentures- why ?

  Plaque   Caries, perio disease   Trauma   Abrasion, forced gingival recession, tissue hyperplasia   Excessive forces   Worsens perio disease, bone loss, mobility

Partial dentures – yes or no ?  So before we rush to make a partial denture, ask yourself:  Will it do more harm than good  Are there ‘safer’ alternatives  Have you explained all the ‘pros and cons’ to your patient  Partial dentures need plenty of maintenance, by you and the patient

Partial Dentures - Benefits  Appearance  Face, lips, smile, sexy  Function  Chewing, biting, gripping, tearing, kissing  ? Helps remaining teeth  Spreads load, prevents tilting, over-eruption  ? Prepares pt for full dentures  (Is this rather defeatist)

Partial Dentures - design  Must minimize plaque build up and allow pt to maintain good oral hygiene  Needs to avoid soft tissue trauma  Should support and stabilize the remaining teeth without producing excessive occlusal or tipping forces  Avoid your partial denture becoming: 1.a ‘gum stripper’ 2.an orthodontic appliance !

Partial Dentures - design  Retention  Stops the denture falling out  Suction, friction, muscular, mechanical (clasps etc)  Resistance or Support  Stops the denture being pushed in (gum stripper)  Tissue or tooth borne ?  Connectors  Joins the teeth, aids resistance & retention  Make it as patient-friendly as possible   Refer Dr Ulpee’s notes on clasps/ rest seats

Resistance or Support  Stops the denture being pushed in  A major cause of trauma to tissues !  Tissue or tooth borne - Which is better?  Teeth are made to take occlusal load  Soft tissues are not !  The effects of ‘sinking’ are:  Trauma to gingivae and forced recession  Damage to mucosa by flanges and connectors  Denture teeth start to look too short  Natural teeth may be tilted, intruded or loosened

Providing Resistance or Support  Bring the acrylic up over the cingulum of anterior teeth,...if the bite allows it ! ✖ ✔

Providing Resistance or Support  Bring the acrylic up over the bulbosity of molars,....if the bite allows it ! ✔✖

Providing Resistance or Support You may need to cut a rest seat

Providing Resistance or Support  Provide metal occlusal rests  With premolars & molars you cannot easily bring the acrylic over the occlusal surface,..but you can fit a metal occlusal rest Your denture will ‘hang’ off the teeth

Providing Resistance or Support  Occlusal rests;  Make the denture ‘tooth borne’  Should be used wherever possible  Are used on ‘strong’ teeth  Need to be positioned carefully  Can be formed from stiff wire and inserted into the arylic

Providing Resistance or Support You may need to cut a rest seat

Providing Resistance or Support You may need to cut a channel for a clasp This will also provide support

Connectors  Do not ‘pinch’ the gingivae  Keep 4mm away  Do not cause food traps  Cross the gingival margins mid-tooth only  Keep the design simple  Avoid cutting across rugae in palate  Follow them instead  Follow anatomical lines if possible

Partial Dentures - planning  As soon as you have your study models, and BEFORE you take your 2’ impressions:  Plan your design, considering all the pros & cons, and your patient’s wishes  You may need to consider:  More extractions  Hopeless prognosis, deep undercuts  Conservation  Reshape opposing teeth,  Cut rest seats, channels for clasps, guide planes  Remove undercuts, create undercuts

Guide Planes & Occlusal Rests

Partial Dentures Lets try to design a few  Follow these principles:  Which teeth are to be replaced  Design connectors and outlines  Avoid palatine papilla if possible  Consider undercuts & path of insertion  Provide resistance & retention  Do any teeth need cutting, reshaping, or exo  Draw on your model & write your treatment plan

Partial Dentures, 2’ Imps  Check your treatment plan  Cut or reshape any teeth as needed, ?undercuts  Check your special tray covers all areas that are crucial to your design  Take good alginate impressions, use your finger  Take your shade  Check the occlusion, ? take a wax bite, you may not need to take MMR using bite blocks

Partial Dentures, MMR  Will only be needed if:  Many teeth are missing  There are free end saddles  There is no tooth to tooth contact  The existing occlusion needs to be raised, or changed in some way (rare)

Partial Dentures, MMR  Check fit and stability of wax blocks  Trim occlusal levels to follow natural teeth  If there is tooth to tooth contact, use this occlusion unless there is a specific reason to change it  Record bite blocks in centric occlusion  Mark centre lines

Partial Dentures, Try - In  Confirm smile lines and levels  Agree aesthetics with the patient  Similar steps to F/F try in:  Assess accuracy of the occlusion  But also:  Check resistance – is occlusion affected  Check retention - will clasps show  Hygiene – are there food traps  Soft Tissues – any risk of trauma

Partial Dentures, Fitting  Try them in gently, never force them  Adjust carefully to ensure a snug fit  Check occlusion, ? Tooth to tooth contact  Check aesthetics, ? Objectives achieved  Ensure comfort, no trauma  Teach patient how to fit and remove them  Don’t use clasps as ‘handles’  Give full cleaning & maintenance instructions  Don’t wear them 24 / 7, give your mouth a rest

Prosthetics Revision  Today we have reviewed:  Partial Denture planning & design  The clinical stages of partial denture construction