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Background: Current radiography techniques have limitations in detecting subtle odontogenic anomalies or defects that can lead to dentoalveolar and facial infections. This report examines the application of micro-CT imaging on two extracted teeth to enable detailed visualization of subtle odontogenic defects that had given rise to facial swellings. Methods: Two extracted non-carious mandibular left primary canine teeth (73) associated with odontogenic infections were selected from healthy patients, and an intact contralateral tooth (83) from one of the patients was used as a control. All three teeth were subjected to the three-dimensional micro-CT imaging at a resolution of 20 μm. Results: Tooth 73 from the first case displayed dentine pores (channels) that established communication between the pulp chamber and the exposed dentine surface. In comparison, tooth 73 from the second case had a major longitudinal crack extending from the external enamel surface into the pulp chamber. The control tooth did not display any anomalies or major cracks. Conclusions: The scope of micro-CT imaging can be extended from current in vitro applications to establish post-extraction diagnosis of subtle odontogenic defects, in a manner similar to confirming histopathological diagnoses in extracted teeth. Ongoing technological advancements hold the promise for more widespread translatory applications. Refereed/Peer-reviewed

Observations are made on the effect of pipelining iterative arrays for multiplication. It is suggested that the best type of latched array for multiplication is the save-carry iterative array. The effect of pipelining on other iterative arrays, including the general multiply/divide array is discussed.

The use of D type flip-flops with a generalised arithmetic array increases its generality, speeds up processes involving divisions and enables the array to be used more efficiently. The calculation of ab/c is used as an example, but it is with large calculations involving a succession of such operations that the array is most useful.

The past five years have seen the rapid development of iterative circuits performing many arithmetic functions. With the present state of l.s.i. technology in mind, this paper retraces the basic steps made in iterative circuit design and suggests that pipelined arrays are the most suitable for manufacture. The paper also suggests how general arithmetic arrays can be modified to perform non-arithmetical functions.

A digital multiplier which can handle complex numbers in any quadrant is described. The multiplier is based on two cellular logic arrays which are fully iterative and which are thus suitable for large-scale integration. Each cell in each of the arrays is based on two conventional multiplier cells.

Sine and cosine series are generated using a cellular complex-number multiplier based on two logic arrays and a cellular dividing array. Digital feedback is used to produce the two series simultaneously to any required accuracy and resolution.

A general iterative array is described, which performs many useful switching functions as well as any combination of the fundamental arithmetic operations.