Orthodontic model analysis in the permanent dentition: A review of past, and current methods

The study models are regarded as the gold standard tool in orthodontics since they aid in the diagnosis, treatment planning and monitoring of the changes that may occur throughout treatment. Besides these, plaster models are also used to monitor growth and clinical audits. A study model accurately replicates the teeth, surrounding soft tissues and occlusion. Traditionally, the orthodontic study models have been used to measure the overjet and overbite, tooth size, arch length, arch width, the curve of Wilson and Spee, space analysis and diagnostic setup. However, plaster models are still preferred by orthodontists since impression-making is convenient, and most patients tolerate them well. With recent advancements in digital technology, intraoral scanners have eliminated the need for conventional impression procedures and plaster models. The digital orthodontic models have overcome the majority of disadvantages associated with plaster models. With the advent of automated analysis using digital models, the entire process of orthodontic treatment planning based on study models has become more convenient and user-friendly. This article aims to comprehend the various model analyses used for diagnosis and treatment planning in the permanent dentition stage and deliver insight into current digital methods.