Fluoride and the Tooth surface

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Questions and Answers

What process occurs during the pre-eruptive stage of fluoride absorption?

Fluoride travels to tooth buds via blood and tissue fluid. (correct)

Fluoride is deposited after the tooth erupts.

Fluoride is absorbed from topical sources.

Fluoride decreases resistance to caries.

What is the composition difference between fluoroapetite and hydroxyapetite?

Hydroxyapetite is formed during tooth eruption.

Hydroxyapetite has a lower resistance to caries.

Fluoroapetite lacks fluoride.

Fluoroapetite includes fluoride instead of hydroxide. (correct)

How can excess fluoride impact enamel development?

It encourages faster eruption of teeth.

It promotes demineralization.

It enhances ameloblast activity.

It inhibits ameloblast activity. (correct)

At which stage does fluoride deposit continue from tissue fluid around the tooth?

Maturation Stage Signup and view all the answers

What is the primary benefit of fluoride in caries prevention?

It makes teeth more resistant to demineralization. Signup and view all the answers

What level of fluoride was found to be optimal for reducing caries?

1ppm Signup and view all the answers

Which report concluded that there is no link between fluoride and cancer?

Knox Report Signup and view all the answers

What was the percentage increase of children with no decay in deciduous teeth due to fluoridation?

15% Signup and view all the answers

What was the finding of the Cochrane Review in 2015 regarding fluoridated water?

Reduces caries in children's permanent teeth by 26% Signup and view all the answers

According to the York Report, what was the association found between water fluoridation and bone fractures?

No association Signup and view all the answers

What percentage of the UK population currently has fluoride in their water?

10% Signup and view all the answers

What risk is associated with fluoride at a level of 0.7ppm?

12% chance of Fluorosis (mottling) Signup and view all the answers

What was the average percentage reduction in caries in deciduous teeth due to fluoridation?

35% Signup and view all the answers

What does infrequent attacks on enamel result in regarding pH levels?

Less time below critical pH Signup and view all the answers

Which of the following correctly describes frequent attacks on enamel?

Increases caries risk Signup and view all the answers

What is the atomic number of fluorine?

9 Signup and view all the answers

In which year was the first artificial water fluoridation experiment carried out?

1945 Signup and view all the answers

Which scientist is known for the '21 cities' studies related to fluoride?

Dr. HT Dean Signup and view all the answers

How is fluorine generally classified on the periodic table?

Halogen Signup and view all the answers

Which event occurred in 1964 related to water fluoridation?

First anti-fluoride campaigns Signup and view all the answers

Who investigated similar staining in Naples, Italy, after learning about Colorado Stain?

Frederick McKay Signup and view all the answers

Which of the following substances is notably reactive with metals to form salts?

Fluoride Signup and view all the answers

Why is fluoride important for dental professionals?

It helps to remineralize enamel and reduce caries risk. Signup and view all the answers

What is primarily lost from the tooth surface during the post-eruptive stage due to bacterial acid?

Calcium and phosphate Signup and view all the answers

What causes the drop in pH during the post-eruptive stage of a tooth?

Bacterial acid production Signup and view all the answers

What is considered a healthy tooth surface during the post-eruptive stage?

Hydroxyapatite rich Signup and view all the answers

What is the process by which calcium and phosphate from saliva help reform the tooth structure?

Remineralization Signup and view all the answers

What role does fluoride play in the post-eruptive stage?

It helps form fluoroapatite Signup and view all the answers

What happens to the pH of saliva during the loss of minerals from a tooth?

It decreases Signup and view all the answers

Which substance from saliva aids in the process of remineralization of the tooth surface?

Calcium and phosphate Signup and view all the answers

Which mineral compound primarily forms the structure of the healthy tooth?

Hydroxyapatite Signup and view all the answers

How does fluoride affect bacterial adhesion to teeth?

By decreasing the wettability of enamel Signup and view all the answers

Which of the following effects on tooth morphology is associated with systemic fluoride?

Shallower pits Signup and view all the answers

What is a primary mechanism by which fluoride helps prevent root caries?

By providing antibacterial properties Signup and view all the answers

What happens to plaque formation when fluoride is present on the tooth surface?

Plaque formation is reduced Signup and view all the answers

Root caries is more common in which of the following patient groups?

Patients with xerostomia Signup and view all the answers

Which of the following contributes to the increased risk of decay in root caries?

Less mineralized surface Signup and view all the answers

How does fluoride aid in remineralization of teeth?

By incorporating into the tooth surface Signup and view all the answers

Which structural change does fluoride not promote in tooth development?

Increasing overall tooth size Signup and view all the answers

What types of fluoride are effective in reducing the risk of root caries?

Both professionally and self-applied fluoride Signup and view all the answers

At what age is the ingestion of fluoride most critical for preventing enamel problems?

0-8 years Signup and view all the answers

What primary effect does excess fluoride have on enamel formation?

It inhibits ameloblast activity Signup and view all the answers

Which of the following is NOT a source of fluoride that can contribute to fluorosis?

Soda beverages Signup and view all the answers

What is a primary characteristic of enamel affected by fluorosis?

White opacities and discolouration Signup and view all the answers

Which of these factors does NOT influence the severity of fluorosis?

Genetic predisposition Signup and view all the answers

What happens to enamel due to hypomineralization caused by excess fluoride?

It becomes more porous and stain-prone Signup and view all the answers

Which fluoride treatment is mentioned as being effective for patients with exposed root surfaces?

Silver diamine fluoride Signup and view all the answers

Study Notes

Fluoride and Tooth Surface

Fluoride, a naturally occurring element, is important in oral health.
Hydroxyapatite makes up 96% of tooth enamel.
Hydroxyapatite is a calcium phosphate compound.
The critical pH for hydroxyapatite is 5.5.
Below this pH, demineralization occurs.
Fluoride's interactions with tooth enamel involve multiple stages and mechanisms: pre-eruptive (systemic fluoride), matrix secretion, maturation, and post-eruption (topical fluoride).
Fluoride is absorbed into enamel, making it more resistant to demineralization.
Fluoride helps form fluoroapatite, which is more stable and resistant to acid attacks than hydroxyapatite.
Fluoride reduces caries incidence as it makes teeth more resistant to further demineralisation.
It is topical fluoride's role in remineralisation that is critical in maintaining a healthy tooth structure.
Professional and self-applied fluoride are noted as essential in caries prevention.

GDC Learning Outcomes

Students should describe the properties of relevant medications and therapeutic agents and discuss their application to patient management.
Students should provide comprehensive and accurate preventative education to patients, encouraging self-care and motivation.
All patient care should follow a preventative approach for long-term oral health consideration
Students should advise on and apply relevant preventative materials and treatment options.
Health promotion, relating to the community and individuals in a changing environment, needs to be discussed and evaluated.

Pre-Reading

The aetiology of dental caries involves the interaction of susceptible tooth surface, plaque bacteria, and fermentable carbohydrates over time.
Histology of enamel and dentine lectures are essential for understanding the topic.

Intended Learning Outcomes

Students will list key milestones in fluoride history and its use in caries prevention.
Students will outline and describe stages in fluoride deposition.
Students will describe fluoride modes of action.
Students will explain how fluorosis occurs.
Students will identify and assess fluorosis severity.

Refreshers Session

Normal enamel is primarily composed of hydroxyapatite.
Hydroxyapatite comprises 96% of enamel.
Enamel has a lattice structure, primarily made up of phosphate and calcium ions.
Hydroxyapatite structure is indicated with Ca10 (PO4)6 (OH)2.
Demineralisation occurs when pH drops below 5.5 for hydroxyapatite, causing tooth surface breakdown into component ions (Ca2+, PO43-, OH-).
Frequent acid attacks increase demineralisation risk; infrequent attacks reduce it.

Fluorine

Fluorine, a halogen, has atomic number 9 and is highly reactive with metals.
Naturally found in water, rocks, soil, and tea.

Fluoride History

Several key milestones in fluoride history, including research, experiments, and the development of water fluoridation for public health.
Identification of Colorado stain led to its investigation.
Water sampling showed higher fluoride content linked to mottling, suggesting fluoride's possible protective role.
Studies linking fluoride to reduced caries rates, including "shoe leather" studies and the 21-city studies.
Various campaigns, including by the Royal College of Physicians, were instrumental.
Different reports, such as the York and Knox reports, evaluated the evidence and links between fluoride and cancer/bone fractures.
Cochrane review (2015) analysed current evidence on fluoride's effect on dental caries.

Colorado Stain-1916

Dr Frederik McKay identified a staining on some teeth.
He sought further investigation from GV Black, whom published a paper on the findings.

Water Sampling -1931

After McKay's findings, Churchill identified higher fluoride content connected to enamel mottling.

Identification Fluoride may reduce caries – 1932

McKay proposed the same substance causing enamel mottling could also reduce caries.

Shoe Leather Studies-1930-1940

Dr H Trendley-Dean studied links between fluoride, mottling and caries reduction following research from McKay.

Knox Report -1985

Reviewed papers on fluoride and cancer, concluding no strong link existed.

York Report-2000

Reviewed various studies involving water fluoridation,finding no link to bone fractures or other health problems.

Modern Day

Controversy exists regarding the use of artificial water fluoridation
About 10% of the UK population currently has fluoride in their water supply.
Patients questions about the continued use of fluoridation continue

How does Fluoride prevent caries

Fluoride is absorbed into the tooth surface which makes it more resistant to demineralization.
This occurs in stages, including pre-eruption, matrix secretion, maturation, and post-eruption.
Fluoride incorporation, reduced surface wettability, and antibacterial effects are different ways it prevents root caries.

Fluorosis

Fluoride ingestion can result in enamel defects.
In excess, it can lead to enamel mottling or discoloration (fluorosis).
The precise effects depend on the dose, ingestion duration, and patient age at exposure.
Fluorosis can be graded, ranging from slightly visible changes to severe discolouration and pitting on teeth.

Mechanism of fluorosis

Excessive fluoride can impede enamel maturation, creating more porous enamel
Fluoride can cause discolouration/staining due to the hypomineralisation of the tooth enamel.
There are more causes of enamel defects besides fluorosis, such as genetics, trauma, disease, and drug interactions, so these must be taken into consideration.

What are the aetiological agents

Dietary fluoride supplements are a cause of oral fluoride intake.
Drinking water, especially fluoridated water, contributes to fluoride ingestion.
Toothpastes, particularly those containing fluoride, have contributed to fluoride intake
Topical applications can also be a cause of oral fluoride exposure

Is it fluorosis

Several criteria distinguish fluorosis from other enamel defects.

Indices for recording fluorosis

The Dean Index and Thylstrup and Fejerskov indices are used to evaluate the extent of fluorosis.
These grades range from 0 (no fluorosis) to 9 (significant fluorosis with enamel loss) and assess translucency.

Summary

Stages of fluoride deposition: Calcification stage(systemic), post-eruption (topical).
Fluoride actions: Action on hydroxyapatite, action on enamel surfaces, action on bacterial enzymes, action on tooth morphology.

Where does the fluoride come from?

Topical fluoride applications provide a reservoir of fluoride in saliva.
Fluoride binds to calcium in saliva to form CaF2.
When acid attacks and pH drops, fluoride is released to help remineralisation

Ways to ensure a regular supply of low-level fluoride

Different topical fluoride sources (toothpastes, mouth rinses, fluoride varnishes, restorative materials, and fluoride tablets) with corresponding fluoride levels and prescription requirements.
Water fluoridation can also contribute but is less topical.

How does fluoride work in real life?

The incorporation of fluoride into tooth enamel.
The change in pH levels affecting the formation of hydroxyapatite and fluorapatite.

Does Fluoride have any other mechanisms of action?

Fluoride can potentially have antibacterial effects and reduce bacteria adhesion to enamel surfaces

Action on enamel surface

Fluoride can decrease enamel surface energy, affecting wettability and inhibiting bacterial adhesion, reducing plaque formation

Action on tooth morphology

The shape and structure of teeth can potentially be altered by fluoride exposure, sometimes improving cleansability.

Root Caries Recap

Gum recession exposes dentine and cementum, surfaces that are less mineralised to decay faster than enamel.
Xerostomia, limited saliva, and radiotherapy can increase root caries susceptibility.

How does Fluoride prevent root caries

Fluoride can incorporate into surface during remineralization.
Fluoride can reduce surface wettability and potentially have antibacterial effects to prevent root decay.

What does the research say

Professionally-applied fluoride (silver diamine fluoride, fluoride varnish), as well as self-applied fluoride (mouth rinses), can prevent root caries.

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