Assessing the effect of piezoelectric ultrasonic scaler tip wear on root surface roughness under influence of various working parameters: A profilometric and atomic force microscopic study

Background

Assessing the effect of scaler tip wear on the root surface roughness using piezoelectric ultrasonic scaling device under influence of various working parameters, i.e. power setting, lateral force, and instrumentation time.

Materials and Methods

An experimental study was conducted using 160 single-rooted tooth samples divided into two groups of new (n = 80) and worn tips (n = 80). Samples were prepared to examine the root surface roughness after being instrumented by new and worn piezoelectric ultrasonic tips (8 new/8 worn) at different parameters. The erosion ratio (ER) of the new/worn tip was examined under an atomic force microscope and roughness over root surface was measured by a contact surface profilometer. One-way analysis of variance test, post hoc Tukey's test, and independent t-test were used for intragroup, pair-wise multiple comparisons and intergroup comparison of average roughness (Ra) value.

Results

A statistically significant difference was found between the ER of new and worn scaler tips (P < 0.001). Intragroup comparison between subgroups 1 and 8 showed a higher Ra value in both the groups (P < 0.005). There was a significantly higher Ra value of worn tips compared to new tips (P < 0.05). Significantly higher mean Ra value was shown when lateral force changed from 50 g to 100 g (P < 0.005).

Conclusions

Increasing value of power setting, lateral force, and instrumentation time caused more surface roughness in worn-out scaler tips compared to new scaler tips. Lateral force and instrumentation time proved to be a major factor influencing surface roughness.

Influence of battery power setting on carbonyl emissions from electronic cigarettes

INTRODUCTION

Although e-cigarettes share common features such as power units, heating elements and e-liquids, the variability in design and possibility for customization represent potential risks for consumers. A main health concern is the exposure to carbonyl compounds, which are formed from the main components of e-liquids, propylene glycol and glycerol, through thermal decomposition. Levels of carbonyl emissions in e-cigarette aerosols depend, amongst others, on the power supplied to the coil. Thus, e-cigarettes with adjustable power outputs might lead to high exposures to carbonyls if the users increase the power output excessively. The aim of this work was to elucidate the generation of carbonyls in relation to undue battery power setting.

METHODS

Carbonyl emissions were generated by two modular e-cigarettes equipped with two atomizers containing coils of different resistance following the ISO 20768:2018 method. The battery power output was increased from the lower wattage level to above the power range recommended by the producer. Carbonyls were trapped by a 2,4-dinitrophenylhydrazine (DNPH) solution and analysed by LC-MS/MS.

RESULTS

The amount of carbonyl emissions increased with increasing power setting. An exponential incline was observed when the applied power level exceeded the recommended power range. Exceeding the recommended power range by just 5 watts resulted in up to twenty times the amount of carbonyls emitted at the recommended upper power level. Generation of acetaldehyde and acrolein next to other carbonyls was prominent at high power outputs.

CONCLUSIONS

E-cigarettes with customisable power setting might generate high amounts of carbonyls if the battery power output is set by the consumer to levels above the recommended range. This represents a high risk of exposure to carbonyls and thus should be avoided by integrating safety features in e-cigarette devices to limit the possible power settings to the range specified by the manufacturer.

Relationship between CO2 laser-induced artifact and glottic cancer surgical margins at variable power doses

BACKGROUND

The carbon dioxide laser can induce thermal cytologic artifacts at the margin of early glottic squamous cell carcinoma histologic specimens, which makes assessment of the margin difficult. This study assesses and correlates the depth of laser-induced thermal artifact with laser power rating.

METHODS

The surgical margins of 30 patients with early glottic squamous cell carcinomas who underwent laser resection were reanalyzed retrospectively.

RESULTS

Thermal damage consisted of collagen denaturation within the vocal cord lamina propria and vocalis muscle, and epithelial structural changes. There was a decrease in depth of tissue artifact with increased power rating (p > .05). The average depth of thermal damage was 380.83 ± 178.79 μm.

CONCLUSION

The laser causes less thermal damage at higher power, presumably because of the increased speed of cutting and reduced contact time with surrounding cells. Knowledge of the depth of thermal artifact is important surgically when ensuring the cancer is excised with sufficient oncologic margin. © 2015 Wiley Periodicals, Inc. Head Neck 38: E712-E716, 2016.