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Dental Tribune Middle East & Africa Edition | 1/2017 22 RESTORATIVE Advanced restorative techniques and the full mouth reconstruction: Duralay Bonnets. Part 7 ByProf.PaulTipton,UK Impressions techniques demand a high degree of accuracy for the completion of advanced restorative cases. Often this is a difficult pro- cedure for the restorative dentist when taking impressions both sides of the mouth at the same time (as a full arch impression where there are multiple teeth present) or undertak- ing an impression of mobile teeth as in the case of a Lindhe/Nyman-style bridge. The following article will review the techniqueofusing‘DuralayBonnets’ or copings as an impression tech- nique and suggest circumstances where the technique would be most appropriatelyused. ComplexBridgework The standard way of completing a full mouth or partial reconstruc- tion is always to follow the following principles: •Establishposteriorstability •Prepareanteriorteeth •Establishcorrectanteriorguidance •Restoreanteriorcrowns/teeth •Restoreposteriorcrowns/teeth In this way, following the basic rules, the full mouth/partial reconstruc- tionisbrokendownintoeasilynego- tiablestages. CompleteCrownand Bridgework However,fromtimetotimetherules aremadeforbreakingandifanterior and posterior teeth are connected together in the form of bridgework, analternativesolutionisrequired.In caseslikethesethesamesteps1-3are taken, however step 4 is preparation of posterior teeth and fitting of pro- totypes. Impressions are then taken of anterior teeth and posterior teeth in three different impressions – i.e. UR,ULandanteriorsandtheimpres- sions are silver plated before duralay copingsaremadeonthem. The technician sends back du- ralay copings, coat hanger wire for strength, special tray, and often a second set of copings to use as a jaw registration. Once the copings are placed onto the tooth preps in the mouth and verified as properly seat- ed,thecoathangerwireisplacedand connected to the individual copings with further duralay using the “dead on technique”. A further pick up im- pressionisthentaken. Onceinthelab,thetechnicianplaces the silver dies into the master im- pressionandcaststhemastermodel. He can then produce his definitive work on this model of the whole arch. In case 1 the gentleman had an upper reconstruction including crownandbridgework.Mr.Wwasre- ferred with missing upper teeth and worn remaining upper dentition (Figs. 1-4). Upon manipulation back to RAP we had an edge to edge oc- clusion. The teeth were individually prepared and mesh prototypes fit- ted(Figs.5,6),andinitialimpressions takenforthedefinitivesilverdyes. Duralay copings were fabricated by the technician and placed onto the tooth preps at the next visit (Figs. 7, 8). These were connected together with duralay and coat hanger wire using the “dead on technique” (Figs. 9, 10). A final impression was then Inpartsevenoftheseries,PaulTiptonreviewsusingDuralayBonnetsorcopingsasanimpression techniqueandsuggestscircumstanceswherethetechniquewouldbemostappropriatelyused Fig.1:Missingandwornupperandlower teeth Fig. 9: Duralay bonnets and coat hanger wire front facialview Fig.17:Silverdiesplusduralaybonnets Fig.5:Upperandwithprototypes Fig.13:Finalcrownandbridgeworkocclusalview Fig.3:Upperocclusalview Fig.11:PickupImpression Fig.19:Duralaybonnetspluscoat hangerwire Fig.7:Duralaybonnetsfront view Fig.15:Toothpreps Fig.2:Edge toedgeocclusioninRAP Fig. 10: Duralay bonnets and coat hanger wire oc- clusalview Fig.18:Duralaybonnetsfront view Fig.6:Prototypesshowingnewclassoneocclusion Fig.14:Mobileupperandlower teeth Fig.4:Loweranteriorview Fig.12:Finalcrownandbridgeworkfront view Fig.20:Impregumpickupimpression Fig.8:Duralaybonnetsocclusalview Fig.16:Silverdies ÿPage23