Study type: Medical/biological study (experimental study)

Effect of long term 900 MHz radiofrequency radiation on enamel microhardness of rat's teeth med./bio.

Published in: Oral Health Dent Manag 2014; 13 (3): 749-752

Aim of study (acc. to author)

The effects of a chronic head exposure of rats to a 900 MHz electromagnetic field on the enamel micro hardness of teeth should be investigated.

Background/further details

21 rats were randomly divided into the following two groups: 1) sham exposure (n=7) and 2) exposure (n=14). Immediately after the last exposure, all animals were anesthetized and their teeth were removed. Ten incisive teeth were analyzed per group and five measurements were taken per tooth, respectively (total of n=50 per group).



Exposure Parameters
Exposure 1: 890–915 MHz
Modulation type: pulsed
Exposure duration: continuous for 2 hours/d for 10 months

Exposure 1

Main characteristics
Frequency 890–915 MHz
Exposure duration continuous for 2 hours/d for 10 months
Modulation type pulsed
Repetition frequency 217 Hz
Exposure setup
Exposure source
  • generator for GSM simulation
Distance between exposed object and exposure source 1 cm
Chamber rats were placed in a Plexiglas tube carousel with their heads oriented towards the antenna of the GSM generator in the middle
Sham exposure A sham exposure was conducted.
Measurand Value Type Method Mass Remarks
SAR 0.0369 W/kg effective value measured and calculated whole body -
SAR 2.023 W/kg maximum measured and calculated whole body -
power 2 W peak value calibration - -

Reference articles

  • Tas M et al. (2014): Long-term effects of 900 MHz radiofrequency radiation emitted from mobile phone on testicular tissue and epididymal semen quality

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Enamel micro hardness was decreased in group 2 (exposure) compared to group 1 (sham exposure) but the difference was not statistically significant.
The authors conclude that a chronic head exposure of rats to a 900 MHz electromagnetic field has no effect on the enamel micro hardness of teeth. However, they presume the existence of a minor effect and propose further studies with prolonged exposure durations to clarify the topic.

Study character:

Study funded by

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