2006) a second study found no significant differences in tooth widths (Mullen, Martin, Ngan, and Gladwin 2007) and a third study found only significant differences for canine tooth widths, recommending a smaller rotational angle during scanning in the canine region to improve accuracy (Nouri et al. One study compared tooth width measurements on digital and plaster models and found some statistically significant differences, but the differences were clinically acceptable (Stevens et al.
#Alginate impression records ndt software#
With further hardware and software developments, improved accuracy will be available. The reports agree that the accuracy of currently available digital models is very good and quite acceptable for use in orthodontic diagnosis and treatment. The accuracy of measurements taken from digital models has been reported in several publications. Through CAD/CAM (computer-aided design/computer-aided manufacturing) procedures, a three-dimensional cast can be created from a digital model. Digitized casts can be forwarded electronically to another clinician when patients transfer from one office to another. Cone beam computed tomography machines can create digital casts. A clinician can send plaster casts or impressions to a company for digitizing. Services and equipment that digitize orthodontic casts and alginate impressions are being marketed to orthodontists. This technology is reducing errors commonly made in recording margins for crowns made in dental laboratories (Shannon, Qian, Tan, and Gratton 2007). Several companies are selling equipment designed to capture digital images of individual teeth and arches for restorative dentistry (Helvey 2009). Even the laboratory fabrication of orthodontic appliances will be accomplished through digital technology. With advances in digital model technology, dentists will eventually no longer take impressions and trim plaster diagnostic casts as described in this chapter. You need high-quality working casts for appliance fabrication. After treatment, study casts will show the changes that occurred during treatment. You must study the positions of the maloccluded teeth, to plan how and where the teeth need to be moved during treatment. For treatment planning, casts are indispensable. Study casts are among the most important records taken prior to, during, and after orthodontic treatment. Even if you are observing a young patient prior to the onset of treatment, study casts are useful three-dimensional records for a growing and changing patient. They contribute greatly to diagnosis and treatment planning and are valuable instructional and illustrative aids during a consultation with patients. Study casts accurately represent the teeth, their supporting tissues, and the relationship between upper and lower teeth in centric occlusion. Dental Impressions and Study Cast Trimming
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