A new method for optimized laser treatment by laser focus navigation and distance visualization

The influence of delivery power losses and full operating parametry on the effectiveness of diode visible-near infra-red (445-1064 nm) laser therapy in dentistry-a multi-centre investigation

The development of protocols for laser-assisted therapy demands strict compliance with comprehensive operating parametry. The purpose of this investigation was to examine the accuracy of correlation between laser control panel and fibre emission power values in a selection of diode dental lasers. Through retrospective analysis using successive systematic review and meta-analysis, it is clear that there is inconsistency in the details, and possible inaccuracies in laser power applied and associated computed data. Through a multi-centre investigation, 38 semi-conductor ("diode") dental laser units were chosen, with emission wavelengths ranging from 445 to 1064 nm. Each unit had been recently serviced according to manufacturer's recommendations, and delivery fibre assembly checked for patency and correct alignment with the parent laser unit. Subject to the output capacity of each laser, four average power values were chosen using the laser control panel-100 mW, 500 mW, 1.0 W, and 2.0 W. Using a calibrated power meter, the post-fibre emission power value was measured, and a percentage power loss calculated. For each emission, a series of six measurements were made and analysed to investigate sources of power losses along the delivery fibre, and to evaluate the precision of power loss determinations. Statistical analysis of a dataset comprising % deviations from power setting levels was performed using a factorial ANOVA model, and this demonstrated very highly significant differences between devices tested and emission power levels applied (p < 10-142 and < 10-52 respectively). The devices × emission power interaction effect was also markedly significant (p < 10-66), and this confirmed that differences observed in these deviations for each prior power setting parameter were dependent on the device employed for delivery. Power losses were found to be negatively related to power settings applied. Significant differences have emerged to recommend the need to standardize a minimum set of parameters that should form the basis of comparative research into laser-tissue interactions, both in vitro and in vivo.

Accuracy study of a new assistance system under the application of Navigated Control® for manual milling on a head phantom

In this article, a technical study of a new assistance system to support surgeons in milling on the temporal bone is presented. In particular, the overall accuracy of a new assistance system was investigated experimentally under conditions close to surgical practice. For the experiment, the assistance system has been used with its associated navigation system for ear-nose-throat (ENT) surgery. A specially constructed head phantom allowed the implementation of reproducible experiments. Thereby, N = 10 specimens were milled by three test persons without medical knowledge and the distance between points on the milled surface and the security zone around the planned nerve for each specimen were calculated. The result was as follows: None of the 10 milled specimens overlapped more than 2mm with the security zone, the average distances to the planned surface of the security zone for each specimen were between 0.01mm and 2.23mm, and the corresponding standard deviations varied from 0.41mm to 1.17mm. But it also shows some variation in averages and standard deviations and it was often too little material removed. This deviation is probably caused by the patient registration and the tool calibration.