TOXICITY OF FLUORIDES Lesson Plan Date and time

TOXICITY OF FLUORIDES

Lesson Plan Date and time : 09. 05. 2018, 8. 00 - 9. 00 am Name of the lecturer : Dr. Rekha P. Shenoy Class : IIIrd BDS Venue : Lecture Hall 2 No. of students : 100 approximately Time : 60 minutes Topic : Toxicity of fluorides T/L Methods : Interactive Lecture T/L aids : LCD, Blackboard

Set Induction: By asking students about their awareness of any ill-effects of fluorides Contents and break up of time: Serial No. Contents Duration 1. Introduction, SLOs and Set Induction 05 min 2. Acute toxicity of fluorides 20 min 3. Chronic toxicity of fluorides 20 min 4. Summary 10 min 5. Evaluation: By asking questions 05 min

Contents: Introduction Acute toxic dose Acute toxicity of Fluorides Chronic toxicity of Fluorides Conclusion

Introduction. . � Fluoride (F) --- ‘a double edged sword’ � inadequate ingestion --- dental caries � excessive intake --- dental fluorosis --- skeletal fluorosis

TOXICITY OF FLUORIDES Acute single ingestion of a large amount of F Chronic long term ingestion of smaller amounts

Acute Toxic Dose. . 1] Certainly Lethal Dose (CLD) or LD 100: � i. e. , 32 – 64 mg F / kg body weight

2] Probably Toxic Dose (PTD) 5 mg F / kg body weight

3] Safely Tolerated Dose (STD) � 1/4 th of CLD can be ingested without symptoms of serious toxicity � 8 – 16 mg F / kg body weight

Acute Toxicity of Fluorides. . rapid excessive ingestion at one time speed & severity of response depend upon -- amount ingested -- weight & age of the individual

Signs and symptoms: � Gastrointestinal � Neurological �Cardiovascular � Blood chemistry

Death due to acute poisoning: • serious symptoms within 1 – 2 hours of ingestion • if first aid not administered, death occurs 2 – 4 hours after ingestion • survival > 24 hours --- prognosis good

Emergency treatment for F overdose: Bayless & Tinanoff (1985) mg F ion / kg body weight Treatment < 5. 0 mg / kg oral Calcium to relieve GIT symptoms; observation; induced vomiting unnecessary 5 – 15 mg / kg induced vomiting; oral Calcium; hospitalization; observation > 15 mg / kg immediate hospitalization; induced vomiting; cardiac monitoring; IV 10 ml of 10% Calcium gluconate; adequate urine output to be maintained; supportive measures for shock

Chronic Toxicity of Fluorides. . • long term ingestion of small amounts of F • seen in areas with > 2 ppm F in the drinking water • effect on enamel = dental fluorosis • effect on bone = skeletal fluorosis

Commonly recognized effects of ingestion of fluoridated water at various levels: Fluoride level Effects 0. 7 – 1. 2 ppm prevents dental caries no dental / skeletal fluorosis 1. 5 – 3. 0 ppm (5 – 10 years) milder forms of dental fluorosis 3. 0 – 8. 0 ppm (15 – 20 years) severe form of dental fluorosis milder form of skeletal fluorosis ≥ 8. 0 ppm (5 – 10 years) severe form of dental & skeletal fluorosis

Skeletal fluorosis seen at water F level > 8 ppm

Symptoms: -- severe pain in backbones, joints, hips -- stiffness in joints & spine -- advanced stage: “knock-knee syndrome” -- severest form: “crippling fluorosis”

Dental fluorosis • “excessive” availability of F during amelogenesis • most susceptible --- 0 to 5 year age group because the anterior permanent teeth are at the early maturation stage

Clinical features: 1. 1 st sign - thin white striae across enamel surface 2. white opaque areas at the cusp tips, incisal edges & marginal ridges 3. irregular paper white areas scattered over the tooth surface 4. brown staining 5. pitting

• severe cases → normal tooth form lost • Fluorosis occurs symmetrically within dental arches • premolar > 2 nd molar > maxillary incisor > canine > 1 st molar > mandibular incisors

Conclusion. . �Excessive intake of fluoride -- dental and skeletal fluorosis Severity of effects on systemic health are varied and warrant use of varying treatment options

Thank you