This refers to the letter by Dr. Mahmood A. Khwaja, ‘Mercury: safe dental
practice’ (Oct 20). We know that mercury amalgam is the oldest filling
material used in the field of dentistry due to its cost effectiveness

According to an early report, in clinics of Karachi, 57pc dentists use the hand-mixing method for the dispensing of mercury.

For the disposal of mercury amalgam waste, 55pc dentists use the sink
and 25pc use bins in their dental clinics. This is most alarming as
such toxic mercury/mercury waste disposal results in high mercury
contamination of indoor air, as is evident from the reported recent
field study/survey by the Sustainable Development Policy Institute
(SDPI) team at 34 dental sites in some of the main cities of the
country. Hazardous mercury exposure puts workers and public health in
general, and children in particular, to a very high risk.

There is a need to create awareness among dentists and dental
teaching institutions to follow the international criteria for the use
and disposal of mercury amalgam so as to minimise mercury releases,
emissions and exposure. It is strongly recommended that students at
teaching institutions and dentists at clinics use capsulated alloys for
dental fillings, use chair-side traps, vacuum pump filters and amalgam
separators to retain amalgam, recycle their contents when possible and
use line cleaners that minimise the dissolution of amalgam and avoid
contamination of water.

At the national level, proper legislation and protocols are needed in
order to phase out mercury. There is also need to revise the curriculum
of dental teaching institutions and colleges to create awareness and
follow the standard procedures for safe handling.

MARYAM SHABBIR ABBASI
Taxila

Phasing down use of mercury

Regarding the letter, “Mercury: Safe Dental Practice”, (Oct 20), in
some of the dental teaching colleges and hospitals, due to lack of
amalgam waste management at dental sites, the unregulated disposal of
mercury in regular municipal and domestic waste and the extracted teeth
that are incinerated, and heat sterilisation of amalgam filling dental
instrument, have given birth to mercury pollution.

The common protocol of amalgam is the mechanised capsule system but
still some dentists manually prepare amalgam by the mixing mercury and
alloy in mortar and pestle.

The remaining mercury is either discarded into trash or sinks. The
mercury or mercury amalgam waste is combined with other waste pointing
no segregation; it is collected and disposed into either regular
municipal waste or sewerage waste water.

The Sustainable Development Policy Institute’s study and review of
curriculum of Pakistan Medical and Dental Council (PMDC), Higher
Education Commission (HEC) and University of Health Sciences (UHS)
followed in different dental teaching institutions of Pakistan indicated
the absence of related topics concerning mercury exposure, oral
injuries due to mercury poisoning, environmental degradation due to
emission and release of mercury, safe environmental friendly management
of mercury waste, preventive and protective measures in case of mercury
spill.

It is an utmost need to teach and train dental professionals and
students to utilise mercury-free alternatives enabling phasing out
mercury from operative dentistry.

It is strongly suggested to PMDC, HEC and UHS to review and revise
their curriculum in dental teaching institutions in the country by the
inclusion of the above-mentioned topics and topics related to
occupational health and safety, and to encourage the best waste
management practice for amalgam waste.