A total of 300 subjects (ambulant patients of the department of oral pathology and microbiology) filled out a questionnaire on lifestyle, dietary habit, previous history of medication, locality of residence, type of mobile used (CDMA or GSM; only group 2), duration of mobile phone usage (number of years and numbers of hours a week), use of headsets (only group 2), wired or not, associated symptoms like headaches, tingling of skin, rashes over the skin and warmth of the ear.
Subsequently, subjects were divided into 2 groups (n=150 each) according to their mobile usage: 1) low mobile phone users (use of mobile phone for less than 5 years and less than 3 hours a week) and 2) high mobile phone users (mobile phone usage for more than 5 years and more than 10 hours a week).
Exfoliated buccal mucosal cells were collected from the same side on which the subject used their mobile phones the most. Only in group 2, a comparative evaluation was done between both the sides of buccal mucosa (right and left).
receiving or making calls was considered as exposure, while net surfing and text messaging was not included; in group 2, 95 subjects were CDMA users and 55 subjects were GSM users and 70 subjects used wired headset while 80 were non-headset users
There was a significant increase in the mean micronuclei count in high mobile phone users (group 2) compared to low mobile phone users (group 1).
In group 2, the number of micronuclei was significantly elevated at the side of mobile phone use in comparison to the opposite side. The micronuclei mean count was also found to be significantly increased in non-headset users compared to headset users. The highest amount of micronuclei was found in users of group 2 without headset, who complained about warmth around the ear.
No significant differences were found between GSM and CDMA users.
The authors conclude that long-term exposure to mobile phones might have genotoxic effects on the oral mucosa and that the use of headsets could attenuate these effects.