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Abstract Dentists are challenged to create solutions for problems that patients present from chipped or missing teeth a collapsed bite or teeth that are irregular or misshapen. A clear diagnosis of the condition often is required for a proper treatment planning. The diagnostic cast helps the dentist to evaluate the condition of the patient's oral condition and for the diagnostic purposes. Casts may also be used as education tools for dentists as they explain characteristics of a patient's bite or particular dental needs. They can also show how a restoration will look when the work is complete.
Diagnostic cast is a life-size reproduction of a part or parts of the oral cavity and/or facial structures for the purpose of study and treatment planning (GPT). Accurate diagnostic casts transferred to a semiadjust- able articulator are essential for treatment planning in Prosthodontics Orthodontics and for Orthognathic surgeries.
Significance of mounted diagnostic casts1 1 This permits examination of teeth without inter- ference from cheek tongue and influence of neu- romusculature.
2 Articulated diagnostic casts permit a detailed analysis of the occlusal plane and the occlusion and the diagnostic procedures can be performed for a better diagnosis and treatment planning (Fig 1).
3 Curvature of the arch in the edentulous region can be determined so that it will be possible to predict whether the pontic/pontics will act as a lever arm on the abutment teeth.
4 Length inclination drifting or rotation of the abut- ment teeth can be accurately gauged to determine preparation designs.
5 Occlusal discrepancies can be evaluated and the presence of centric prematurities or excursive interferences can be determined.
6 Sometimes patient has to undergo extensive ena- meloplasty to meet the treatment goal. In such situations the patient is informed in advance that additional time will be needed and expense will be greater to avoid doubt or disappointment in treatment.
7 Diagnostic waxing can be rehearsed on the casts and diagnostic waxing procedures allow evaluation of the eventual outcome of the proposed treatment.
IMPRESSIONS FOR DIAGNOSTIC CASTS Accurate impressions are mandatory for diag- nostic casts. Irreversible hydrocolloids are the com- monly used impression material but an elastomeric impression may be required when accuracy is critical as in cases of diagnosing occlusal problems or when multiple...