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Dental Tribune Middle East & Africa Edition No.2, 2016

Fig. 1: Initial situation: The patient was referred to an or- thodontist. Fig. 3:The veneers were removed and the teeth were tran- silluminated toidentifyanycompositeresidue. Figs8aandb:Try-inof theveneerswithalight try-inpaste(Light+) Figs9aandb:Try-inof theveneerswithadark try-inpaste(Warm+) Fig.5:Temporaryrestoration Fig. 6: Try-in of the IPS e.max Press HT A1 veneers (fabricated in the labora- tory) Fig.7:Try-inofthepolished IPS e.max CAD A1 veneers (fabricated in the dental office) Fig.4:Thetwo-cordtechniquewasusedfortheimpression. Theretractioncordsremainedin thesulcus. Fig. 2: One year later when the patient returned to the practice, the teeth showedunsatisfactorycompositeveneers. Dental Tribune Middle East & Africa Edition | 2/2016 25 aesthetics Two approaches and one goal State-of-the-artCAD/CAMmaterialsareofferingcliniciansthepossibilityofproducingcertain typesofrestorationsinthedentalpracticeusingasemi-directtechnique.Ceramicveneers,for example,areeasytofabricatein-officewithIPSCADMulti,withouttheneedforglazing. ByDr.EduardoMahn,Chile Recently developed restorative ma- terials have opened up a myriad of exciting possibilities for dental practitioners. In the restoration of anterior teeth, clinicians have to se- lect the most appropriate material for the case at hand on the basis of specific criteria. In situations where teeth show signs of erosion, abra- sion, abfraction or a combination of these phenomena, practitioners will tend towards using ceramics or compositeresins,dependingonhow muchintacttoothstructureremains available. Traditionally, composites areusedforClassIII,IVandVdefects. However, ceramic veneers are pre- ferred in cases where a large amount of tooth structure is missing or a major change is planned (e.g. smile makeover). Thechallenge When two central incisors need es- thetic enhancement, the choice of approach is not so clear. Irrespective of the material used a minimally invasive route involving very little preparation of the tooth structure can be taken nowadays due to the high strength of modern materials (e.g. lithium disilicate glass-ceramic). Nevertheless, it is important to re- member that minimal preparation is an option, only if the teeth are properly aligned. As long as the de- sired changes of the tooth shape and shade are small, preparation can be limitedtotheenamel. In many cases, however, ortho- dontic treatment is needed before the tooth position and/or shape can be optimized by means of restora- tive procedures. This minimally in- vasive approach requires the dental practitioner to convince the patient of the necessity of undergoing pre- liminaryorthodontictreatment. Thesolution It is our aim to remove as little of the tooth structure as possible in every case that we treat. With modern ma- terials such as lithium disilicate or leucite-reinforced ceramics, we can confidently press or mill veneers that are as thin as 0.5 mm and even 0.3mm.Oneofthemainadvantages offered by this type of ceramic is its wide range of applications. Until a few years ago, the treatment with in- direct restorations required at least twoappointments. Ceramic materials such as IPS Em- press® CAD allow dental practition- ers to produce poly- chromatic monolithic veneers and crowns in less than one hour, without having to glaze them. Nonethe- less, many dentists stillbelievethatdental technicians with their well-honed manual skills produce better esthetic results than a machine, and they do not see the need to embrace digital technology. As a result of this point of view and the high acquisition costs of the milling machines some clinicians are reluc- tant to invest in this technology. On the basis of the present clinical case study we would like to highlight the following aspects: the importance of having the right treatment plan, the possibilities currently available for thefabricationofveneers,thepoten- tial of the press and CAD/CAM tech- niques and the latest improvements madeinthefieldofcementation. Clinicalcase Patient history A thirty-one-year-old female patient came to our office because she was dissatisfied with her anterior teeth. She complained about the mis- alignment of the upper and lower central incisors (Fig. 1). A detailed clinical examination revealed that the composite restorations in these teeth were defective. As a result of erosion, a considerable amount of tooth structure had been lost. In ad- dition, the misalignment of tooth 21 and 41 in particular was quite obvi- ous. The treatment plan presented to the patient included initial ortho- dontic treatment followed by mini- mal preparation of the two central incisorsfortwoceramicveneers.The patientwassubsequentlyreferredto an orthodontist for treatment. Un- fortunately, it took more than a year before she presented to the practice again. At this consultation, we were quite surprised to find that the two central incisors had been restored with poorly finished direct compos- ite veneers (Fig. 2). Many clinicians simply underestimate the challeng- ingnatureofthistypeofrestoration, and this was a case in point. In addi- tion to preventing any contamina- tionoftheworkingfield,theclinician must also accomplish the arduous taskofcreatinganappropriateemer- gence profile, proper contours and contact areas and producing a suit- able micro and macro-texture, and allthiswithinasingleappointment. Thetreatment The composite veneers had to be re- moved and replaced with new ones. In this particular case, the advan- tages of using the indirect technique were obvious. The patient agreed to have two ceramic veneers made for her. For this purpose impressions were taken and a master cast was produced. This working model pro- vides the dental technician with the opportunity to evaluate the situa- tion in detail. He or she has the time to think about possible ways of cor- rectingthemisalignment. Dentists do not have this “luxu- ry” of time when they are treating a patientinthedentalchair.Theyhave to finish the restorations as quickly as possible in order to prevent con- tamination of the treatment field and keep chair time to a minimum for the comfort of the patient. In the present case, an additional hur- dle had to be overcome: Any com- posite material that might have re- mained on the tooth structure had to be clearly identified and carefully removed without damaging the healthytoothstructure.Transillumi- nation with white LED light came in “Withtheadventof CAD/CAMtechnology, cliniciansnowhave thepossibilityof makingsemi-direct restorations.” ÿPage26 Dr. Eduardo Mahn, Chile is a speaker at 11th CAD/CAM & Digital Dentistry Int'l Conference! 06-07 May 2016 | Jumeirah Beach Hotel, Dubai, UAE Dental Tribune Middle East & Africa Edition | 2/201625

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