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Restorative


clinical stages Articulator selection and


In the second in his series of articles on advanced restorative techniques, Dr Paul Tipton looks at the full/partial mouth reconstruction


T


he full mouth or partial reconstruction is one of the most challenging procedures in restorative dentistry. In order to successfully restore


and maintain teeth, the dentist must find out why the teeth arrived at this state of destruction. Tooth wear can result from abrasion, attrition, and erosion as well as iatrogenic problems with previous resto- rations. Research has shown that these mecha-


nisms rarely act alone and there is nearly always a combination of processes. Evaluation and diagnosis should account for the patient’s diet, the present state of the occlusion and dental history. Emphasis must be placed on the evalua- tion of occlusal prematurities preventing condylar seating in RAP. Factors that may contribute to parafunc-


tional habits or bruxism are important to understand and manage in order to successfully restore and maintain the newly restored dentition. When there is a complete understanding of the etiology of the current condition a treatment plan can be established, taking into account the number of teeth to be restored, condylar position, space availability, the


vertical dimension (VD) of occlusion, the choice of restorative material and the choice of articulator and ways of programming it.


Articulator selection There is a large choice when assessing what type of articulator is correct for the patient and restoration. In terms of classi- fication, articulators range from hand held casts or simple hinge articulators to fixed condyle or average value articulators to semi-adjustable and fully-adjustable. When dealing with the complexity


of the full mouth or partial reconstruc- tion the choice narrows to average value versus semi-adjustable versus fully-adjustable. The accuracy of the articulator also depends upon how it is used and programmed. All of these articulators require the use of facebow, arbitrary or kinematic (to record the true hinge axis) to mount the upper cast. Mounting the lower cast to upper cast is then done with an individual jaw registra- tion taken at an open vertical if mounting around RAP and closed vertical if mounting around ICP. Finally, with the semi-adjustable and fully-adjustable, programming of the


posterior (condylar) determinants of occlusion can be done using lateral and protrusive check bites, cadiax recording or by using a pantograph. The more adjustable the articulator


the more accurate the restoration can be. However, all articulators have limitations and are only as accurate as the dentist/ technician that is using it.


Restorative stages – case study one This gentleman was referred for treat- ment of his severe upper anterior wear. The patient was over closed and, due to the wear, now in a pseudo-class III edge-to-edge occlusion (Fig ı). After initial diagnostic stages which included cosmetic imaging, diagnostic waxing (Fig 2) etc., the patient was ready for initial tooth preparation.


Tooth preparation This will be dependent upon the type of restorative material to be used, for instance PFM, scanned and milled porcelain, adhe- sive porcelain. Whilst the shift in recent years has been to all ceramic restorations, the PFM is often the restoration of choice as it allows a more conservative prepara-


Fig 1 – Anterior tooth wear and class 3 occlusion due to loss of VD


Fig 2 – Diagnostic wax-in


Fig 3 – Tooth preparation and dentine bonding


48 Scottish Dental magazine


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