Burtonian Line: Cause, Color, Mechanism, Symptoms

In this post on the Burtonian line, you get to know about its causes, principle, source of origin, and other signs and symptoms related to lead poisoning like saturnism, coli, etc. along with a case study.

For those, who just want the quick definition of it is defined as:

Burtonian line is a classic symptom of chronic lead poisoning that appears as stippled blue-colored lines on the gingival surface of teeth. It is also called Burton’s lines. There are other color variants of Burtonian lines which may be due to mercury.

Moreover, this post also has a FAQ section that further enriches your knowledge of Burton’s line.

What is the Burtonian line?

burtonian line is seen in

The Burtonian line is defined as a stippled blue-colored line on the gingival surface i.e. the coupling place of gums and teeth, which is commonly seen in chronic lead poisoning. These lines are especially seen on canine teeth of the upper jaw and, within a week of exposure.

Moreover, these stippled blue lines are only seen in only 50-70% of patients suffering from chronic lead poisoning.

Other names of Burtonian lines are:

  • Burton’s line
  • blue lead line gums

Note 1: It is noted that it is not seen on the teeth surface but on the sub-epithelium surface of the junction of teeth and gums.

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Causes of Burtonian Line

Cause of Burtonian Line

Burtonian lines are seen in chronic lead poisoning because of the formation of lead sulfide on the gingival surface of teeth. The mechanism of causing it follows the reaction between circulating lead with the Sulphur ions released by bacterial decomposition in the oral activity.

Color of Burtonian Lines

The Burtonian-causing chemical lead sulfide is white in color but due to oral bacterial activity, its color changes to blue. It can also be possible that, with the passage of time, the color changes to purple-blue or bluish-black in color.

Mechanism of Formation of Burtonian Line

Mechanism of Formation of Burtonian lines

The mechanism of lead poisoning is divided into three major stages. These are:

  1. Inhibition and Lead Circulation
  2. Formation of Hydrogen Sulfide in the mouth
  3. Burtonian Lines Formation

Stage 1: Inhibition and Lead Circulation

When lead is mixed with the blood, it combines with sulfhydryl groups and interferes with ferrochelatase, δ-ALA dehydratase, mitochondrial oxidative phosphorylation ATPases which is a calcium-dependent messenger.  

This inhibits the body from making hemoglobin, which may further become the cause of anemia.

Stage 2: Formation of Hydrogen Sulfide in Mouth

The production of hydrogen sulfide in the mouth is possible because of the presence of various molecules, like volatile sulfur compounds, short-chain fatty acids, polyamines, and indoles.

However, major bacteria that are responsible for the production of hydrogen sulfide are genera Neisseria, Fusobacterium, Porphyromonas and SR1 (Abscondita Bacteria).

Stage 3: Burtonian Lines Formation

Because of bacterial activity, hydrogen sulfide is formed in the mouth that further reacts with circulating lead to form lead sulfide at the junction of gums and teeth.

At first, the lead sulfide is white in color, but with time it changes to blue and blue-black which is called Burtonian or Burton’s lines.

Reaction involved in Burtonian line.
Mechanism of how lead poisoning causes Burtonian line.

Sources of Chronic Lead Poisoning

As Burtonian line are caused by chronic lead poisoning, so in this section, only covers sources that cause chronic lead poisoning:

Note 3: Chronic lead poisoning results from a daily intake of 1–2 mg of lead.

  1. Inhaled or Ingested: One of the most common sources is the ingestion of lead dust which is generally seen in industrial works.
  2. Lead Paints Dust: Lead carbonate called white lead is used for the manufacturing of paints. It is the most common source of lead poisoning in children because of their tendency to put things in their mouths.
  3. Occupations exposure: Occupations like painters, workers in the white lead industry, plumbers, glass polishers, and glass blowers all encounter the fumes of lead.
  4. Tetraethyl lead from Petrol: Tetraethyl Lead is used as an anti-knocking agent in petrol and gasoline.
  5. Cosmetics and sindoor: A red color compound of lead called lead tetroxide or vermilion, generally used as a sindoor in India, can be absorbed through the scalp. And the use of hair dyes and cosmetics containing lead.
  6. From beverages and food: Absorption from drinking water stored in lead bottles, and processed food packed within lead containers.

Other Symptoms Apart from Burton Line

There are many key symptoms to register a person as a patient of lead poisoning.  These are:

  1. Anemia
  2. Colic
  3. Foot drop, Wrist drop, or Lead palsy

Symptom 1: Anemia

Due to impairment in heme synthesis and increased fragility of RBCs.

RBCs fragility increased in case of lead poisoning due to the loss of intracellular potassium. It can be understood as the increased permeability of the cell membrane to potassium.

Symptom 2: Colic

It is a late symptom, seen in the small and large intestines, ureters, and blood vessels.

And the pain in muscular contraction and relaxation might be very serve termed saturnine colic.

Symptom 3: Foot drop or Wrist drop or Lead Palsy

It is a rare symptom seen in less than 10% of lead poisoning cases. It occurs due to the degeneration of nerves and muscle groups.

Note 4: lead poisoning peripheral smear:
It is a peripheral blood smear test, performed on a person suspected of exposure to excess atmospheric lead.
It is performed because the person doesn’t show any symptoms related to lead poisoning.

Burtonian line in Other Metals:

These symptoms are not only seen in lead poising but also seen in:

  • Blue-line on gums (Mercury): In the case of mercury poisoning, the blue line on gums is very rarely seen but the loosening is common.
  • Bluish-colored lips (Iron Poisoning): Blue lips, palms of hands along with fingerprints are the late symptoms of an iron overdose. But the blue gums are not majorly seen in iron poisoning.
  • Copper Poisoning: Apart from the blue line, a more greenish line on the gums at the base of teeth just like the Burtonian line appears.
  • Bismuth Blue Gums: The blue gums in case of bismuth poisoning are called bismuth line or Bismuthia. It is commonly seen in people who have ingested bismuth compounds.

However, in some cases, no color change or lines are seen on the gums but maybe on the skin. They appear as bluish-gray skin pigment granules.

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Case Study

Burtonian line in a 44-year adult battery worker

In India, a 44-year-old male was diagnosed with chronic lead poisoning.

Case History:

He started to work as a child laborer in a battery-recycling unit at the age of 10 years. After the passage of years, he owned the shop and hired two more laborers.

The shop doesn’t possess any health-related precautions. They don’t even use mask. He regularly used to work with molten lead without any protection or mask.

Even if he eats his meal at the workplace without washing his hands, this was also a possibility of accidental ingestion of microparticles of lead through the passage of these years.

Even he uses the workplace as his overnight stay and for sleep without changing his clothes.  

For a long time, he remained asymptomatic i.e. no particular signs and symptoms of the disease. He was initially treated for his symptoms of pain before knowing the root cause of the problem.

But later when his condition got worse, he went through a full diagnosis where subsequent investigations revealed that he was suffering from chronic lead poisoning.

Key Symptoms That Were Seen:

Asymptomatic: The patient doesn’t show any symptoms related to lead poisoning for a long period of time.

This is common in the case of lead poisoning.  For this, a peripheral blood smear test is performed to check the lead level in the blood.

Colic: At prolonged exposure for 34 years, his body showed late symptoms like joint pain, muscular contraction, small intestine, and epigastrium.

Burtonian Line: Burton blue lines were seen in this case but after a long period of exposure.

Bottom-line of the Case Study

As a patient for a long period remained asymptomatic. And he used to take medication for his joint pains and epigastrium without being aware of the actual reason.

So, the patient is unaware of the ill effects and he isn’t able to correlate his joint pain, epigastrium, and burtonian line with chronic lead poisoning.

FAQ Section on Burtonian or Burton Line

Q1. Industrial worker with blue lines on the gingival surface, most probably due to:

Lead poisoning

Q2. What are the other names of Burtonian lines condition?

Burton’s line or blue lead line gums

Q3. Which enzymes are inhibited by lead in the heme synthesis pathway?

Ferrochelatase and δ-ALA dehydratase

Q4. Which cells show basophilic stippling?

Red Blood Cells (RBC’s)

Q5. Which chemical compound of lead is responsible for the Burtonian line?

Lead Sulfide (PbS)

Q6. In case of chronic lead poisoning, the levels of which amino acid is elevated because of

δ-aminolevulinic acid

Q7. Bacteria are responsible for the production of Hydrogen Sulfide in the mouth.

Neisseria, Fusobacterium, Porphyromonas, and SR1 (Abscondita Bacteria).

Q8. What is the lead compound used as an anti-knocking agent that can cause lead poisoning?

Tetraethyl Lead

Q9. Blue-line gums in case of Bismuth poisoning is called:

Bismuthia or Bismuth Blue Gums.


  • https://www.amjmed.com/article/S0002-9343(12)00286-0/pdf [URL]
  • https://www.karger.com/Article/PDF/000098100 [URL]
  • https://pubs.acs.org/doi/abs/10.1021/ja00175a019 [URL]
  • https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6522252/ [URL]
  • https://www.ncbi.nlm.nih.gov/pubmed/6175210 [URL]
  • https://www.familiesagainstchemicaltoxins.org/lead-in-school-drinking-water [URL]

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