Aim: To propose a quantitative classification scheme that is useful for all impacted teeth as well as to describe their angulations, relationships to adjacent teeth and proximity to adjacent vital structures.
Materials and methods: The abbreviation SPAN was used as a system of classification. S stands for size, which indicates the relationship of the mesiodistal diameter of the impacted tooth to its normal space. P stands for the position, which indicates the relationship of the most occlusal point of the impacted tooth to the crown of the mesial tooth or distal tooth if the mesial tooth is missing. A stands for angulations, which means the relationship of the long axis of the impacted tooth to that of the adjacent mesial tooth or distal tooth if the mesial one is missing. N stands for proximity to vital structures.
Results: This proposal has been applied to some radiographic examples and was found to be effective.
Conclusion: This proposal is effective and inexpensive as it only depends on panoramic views. Cone beam computed tomography (CBCT) may become readily available in the future and decrease radiation exposure and expenses, making future classifications more accurate, easier and beneficial.
Clinical significance: The scientific rationale for this study is to propose a quantitative classification system for the impacted teeth. This system can be applied to all impacted teeth by using a panoramic view, which is less expensive and readily available. It also describes angulations, space available, depth, and the relationship of the impacted teeth to vital structures. By applying this scheme, the clinicians can quantify surgical difficulty.
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