The role of stationary intraoral tomosynthesis in reducing proximal overlap in bitewing radiography

Objectives: This study examined the utility of stationary intraoral tomosynthesis (s-IOT) in opening proximal contacts in bitewing radiography. Methods: 11 DENTSPLY Rinn Dental X-ray Teaching and Training Replica mannequins (Model #546002, Elgin, Ill) were imaged with a prototype s-IOT device (Surround Medical Systems, Morrisville, NC) and standard bitewing (SBW) technique. Premolar and molar bitewings were acquired with each system. Image receptor holders were used to position receptors and aid in the alignment of the position indicating devices. An expert operator (having more than 5 years of experience in intraoral radiography) acquired the images with the s-IOT prototype and standard intraoral X-ray devices. Images were assessed to analyze percentage overlap of the proximal surfaces using the tools available in ImageJ (NIH, Bethesda Maryland). Results: 253-paired surfaces were included in the analysis. The difference in overlap was statistically significant with standard bitewing (SBW) images resulting in a median overlap of 13%, a minimum of 0%, a maximum of 100% and an interquartile range of 40%. s-IOT resulted in a median overlap of 1%, a minimum of 0%, a maximum of 37% and an interquartile range of 0%. The s-IOT prototype substantially reduced proximal surface overlap compared to conventional bitewing radiography. Conclusions: The use of s-IOT reduced proximal contact overlap compared to standard bitewing radiography for an experienced radiographer. Stationary intraoral tomosynthesis may be a potential alternative to SBW radiography, reducing the number of retakes due to closed contacts.

Ambient dose during intraoral radiography with current techniques: part 3: effect of tube voltage

Objectives: This study was conducted to assess the impact of tube voltage on ambient dose during intraoral radiography, specifically remnant-beam transmission and scattered radiation. Methods and materials: Remnant-beam and scattered radiation doses were recorded using a phantom at tube voltages of 60, 63, 66, and 70 kV. Mathematical equations depicting their relations were then formulated, and reference values were calculated at the various voltages tested. Total ambient doses per exposure at 60 kV and at 70 kV were compared. Results: Both remnant-beam transmission and scattered radiation increased ~40% by increasing tube voltage from 60 kV to 70 kV, and the relation was linear. A remnant beam transmission reference value of 7.5% was established at 70 kV, as well as a conversion factor of 0.035µSv/mAs at one meter for scattered radiation at 60 kV. Given longer exposure times at 60 kV, total ambient dose proved higher at 60 kV than at 70 kV. Conclusion: Higher tube voltage results in higher remnant-beam transmission and more scattered radiation per workload. The relation is linear in the range between 60kV and 70 kV. Remnant-beam transmission at 70 kV is safely assessed at 7.5%. A conversion factor at 60 kV of 0.035 µSv/mAs at one meter for the scattered radiation dose can be proposed. Total ambient dose per exposure was higher at 60kV than at 70 kV.