Although worn by rappers such as Flava Flav as early as the 1980s, the multi-million dollar business of mouth grills – also known simply as "grillz" – sprouted seemingly out of nowhere around 2005 after rap artist Nelly released a song in their honor. They come in gold, platinum or silver, according to a wearer's preference, and may be accentuated with diamonds, other gemstones, symbols or initials. Typically, however, everyday people seeking to mimic the style of celebrity icons cannot afford the quality and expertise required to maximize grillz safety – which leads to detrimental dental consequences.

Merchants who sell mouth grills outside dentists' offices may either work with dentists, under the guidance of dentists or entirely on their own with no dental training or licensing whatsoever – despite that unlicensed practice of dentistry is a third degree felony. States that regulate the industry specify that impressions may only legally be crafted by dental professionals in dental offices.

Professional dentists use a mixture of surgical-class metals proven safe for use people's mouths. Some non-professionals, however, use metals of dubious quality – including melted down jewelry or even old silverware. Such unapproved metals pose potential dangers like allergic reactions, not unlike when a cheap ring or necklace turns your finger or neck green. Merchants may also be dishonest about how many karats a customer is getting. In 2006, one dentist reported to Channel 7 News in Miami/Fort Lauderdale, Florida, that after testing merchant samples, he found that some were not the quality of material merchants claimed they were.

When wearers keep grillz in their mouths too long – for days, weeks and even months at a time – their teeth literally decay due to poor dental hygiene. Food particles become stuck and accumulate within grillz, leading to development of bacteria and acid on teeth and gums. Even when grillz are removable and not worn long enough at a time to cause decay, grillz leave teeth more subject to cavity formation and bad breath.

As grillz bite against teeth somewhat while in position, a wearer's oral tissue becomes irritated, teeth enamel wears away, bone density weakens and teeth may shift, break or chip. As grillz bite against the gums, they develop cuts and bleed, or swell or redden due to damage or inflammation. Food particle accumulation also leads to gum disease.

To minimize potential of harmful consequences of grillz, consult with a dentist before acquiring them. Wearers should remove grillz before eating or sleeping, brush and floss their natural teeth daily, and clean the grill daily with water. Occasionally, for a thorough cleaning, use a non-toxic jewelry cleaner – toxic jewelry cleaners are unsafe to ingest. For wearers with cemented grillz, dental hygiene is a bigger challenge, and these people should seek dentist's recommendations for plaque control aids.