Dental Indices for Epidemiology

• Epidemiology investigations require quantifying disease occurrence and severity.
• Measurement involves assigning values to characteristics using specific rules and indices.
• This should be done with certain methodology and criteria

Dental Index

• Abbreviated measurement of oral disease amount or condition in a population
• Based on a graduated numeric scale with defined upper and lower limits

Objectives of Indices

• Increase understanding of disease processes for better control and prevention.
• Identify at-risk populations and define specific problems for investigation.

Attributes of a Good Index

• Valid
• Reliable
• Clear, simple, and objective
• Sensitive to disease shifts
• Acceptable to participants
• Amenable to statistical analysis

Validity

• An index must measure what it intends to measure.
• It should align with the clinical stages of the disease under study at each point.

Reliability

• An index should measure consistently across different times and conditions.

Clarity, Simplicity, and Objectivity

• The index should be easy to apply, minimizing time lost during field examinations.

Sensitivity

• The index should be able to detect reasonably small shifts of disease in either direction.

Acceptability

• The index use should not be painful to the subject.

Analysis Amenable to Statistical Analysis

• The index should allow for statistical analysis, so a corresponding number on a scale from zero to an upper limit can express the group's status.

Classification of Indices

• Based on the direction in which their scores can fluctuate

Irreversible Index

• Measures conditions that will not change.
• An example is an index measuring dental caries using the DMF index

Reversible Index

• Measures conditions that can be changed
• Examples include indices measuring gingival conditions.

Full Mouth Index

• Measures the entire periodontium or dentition.
• Russell's Periodontal Index(PI).

Simplified Index

• Measures only a representative tooth sample.
• Green and Vermilion's Oral Hygiene Index – Simplified (OHI-S).

According to Entity measured

• Disease Index: Measures the decay portion of the DMF index.
• Symptom Index: Measures gingival conditions.
• Treatment Index: Measures the filling portion of the DMF index.

Indices Used for Assessment of Oral Disease

• DMFT was introduced in 1938 by Henry Klein, Carrole E. Plamer and Knutson J.W.

DMFT

• Used to determine the prevalence of coronal caries.
• Simple, rapid, and useful for measuring dental caries.
• The index is based on the principle that dental hard tissue is not self-healing, and established caries leaves scar.
• As such, it is the most universally used
• Since the tooth either remains, is decayed, extracted, or filled, the DMF index is irreversible
• Measures life-time dental caries.

Procedure Methodology

• DMF index (Decayed, Missing, Filled) for permanent teeth.

Components of the DMF Index

• D describes decayed teeth
• M describes missing teeth due to caries only
• F describes teeth filled because of caries

All 28 permanent teeth are examined except

• Third molars
• Un-erupted teeth

The procedure excludes:

• Congenitally missing and supernumerary teeth..
• Teeth removed for reasons other than dental caries, like orthodontic treatment or impaction
• Teeth filled for other reasons like fracture, cosmetics, etc..
• Primary teeth are retained when the permanent successor has already erupted

Identification Of Dental Caries

• The explorer tip can penetrate deep into soft, yielding material.
• Discoloration or loss of translucency or demineralized enamel.
• Softness exists at the cavity base.

Examination Method for DMF

• D: A tooth can only be counted once, and if there is defect filling secondary caries are counted as decayed.
• M: Indicates the number of missing permanent teeth due to decay only.
• F: Indicates restored permanent teeth attacked. A tooth with several fillings counts as one tooth

Index Calculation

• DMFT calculation for decayed, missing, or filled permanent teeth.
• Individual DMFT = D+M+F=DMF.
• Group average is the total DMF divided by the total number of subjects examined.

Maximum DMFT Score

• The maximum DMFT score is 32 (range from 0-32).
• DMFS (Decay, Missing, Filled, Surfaces) assesses each individual surface of each tooth.
• DMFS principles, rules, and criteria align with the DMF index, but all surfaces are counted.

Examination of Surfaces

• Anterior teeth (facial, lingual, mesial, and distal) four surfaces

• Posterior teeth (occlusal, buccal, lingual, mesial, and distal) five surfaces

• If 28 teeth are examined for the DMFS index:

• Anterior teeth = 12(12X4)=48 surfaces.

• Posterior teeth=16(16X5)=80 surfaces.

Caries for Primary Teeth

• Gruebbel described (def) as equivalent index to DMF index Used for measuring dental caries in primary teeth

Gruebbel index Components

• d= decayed deciduous teeth
• e= deciduous teeth indicated for extraction due to dental caries
• f= restored deciduous teeth that decayed without recurrent decay

dmf Index

• Modified (def index), includes dmft index (d= decayed, m= missing, and f=filling).
• df index ignores missing teeth to work around exfoliation issues
• The index is applied to whole teeth: dft or to the surfaces to count as dfs surface

Mixed dentition

• DMFT/DMFS and dmft/ dmfs are never added together in patients with mixed dentition.

Index for Root Surface Caries

• Root Caries Index developed by Katz in 1979, used to count carious root surfaces.
• The Gingival Recession must occur before root caries surface lesion begin
• Only teeth with gum recession are examined.

Examined root surface

• The following are examined*
• mesial
• distal
• lingual
• buccal
• labial

Evaluation of No Recession

• Cannot visualize CEJ junction when no gum recession has occurred

The root Caries calculation Uses Formula:

• RCI= (R-D)+(R-F)x 100 (R-D)+(R-F)+(R-N)
• Where:
  • R-N =Recession present surface normal or sound
  • R-D =Recession present with decay root surface
  • R-F= Recession present with a filled root surface.

Indices Used for Assessment of Periodontal Disease

• Occur after microscopic lesion cause by bacteria in dental plaque
• Apply numerical value used for quantitating and evaluating factors studied

Dental Plaque

• Complex
• Metabolically interconnected
• Highly organized
• Bacterial ecosystem
• Soft deposit with microorganism on tooth surface

Gingival inflammation

• An inflammatory process of the gingiva

Periodontitis

• Characterized by loss of attachment of periodontal ligament

Calculus

• a hard deposit that forms thru mineralization of dental plaque

Two main types of calculus depending on location:

• Supragingival: extended to the free gingival margin and is visible in the oral cavity
• Subgingival: deposit apical, and is not visible during examination

Dental Plaque Index-PII

• Described by Sliness P, and Loe, in 1964
• Measures the thickness of plaque on the gingival third
• Used as a full mouth index
• permanent teeth indicator: 6,2,4
• primary teeth indicator: E,B,D

Examination Area:

• The following are examined or assigned double score for mesial reading
  • Facial
  • Lingual
  • Mesial
  • Distal

Scoring Criteria:

• No plaque seen by the necked eye
• Film plaque adhering to the free gingival margin
• The probe can detect it or the disclosing gent is used

Accumulation

• A thin to moderate accumulation of soft deposit detected by necked eye
• Abundance within gingival pocket detected on tooth and margin

Index calculation

• PII=sum/examined surfaces.

Gingival Index GI

• It was developed in 1963 by Loe and Silness P*
• Assesses severity of gingivitis
• Instrumentation includes mirror and blunt explorer probe
• widely used due to accuracy and easy use

Gingival Index score

• 0: normal
• 1: color change, edema, no bleeding
• 2: glazing, redness, edema, bleeding
• 3: marked redness, ulceration, bleeding.

Calculation

• GI = total scores/total examined.

Score Interpretation:

• There scores relate to the nature of gingivitis
• 0.1-1: mild
• 1.1 to 2: moderate
• 2.1-3: severe

Community Periodontal Index Of Treatment (CPITN)

• It was made by; WHO and FDI in 1982*
• Advantages
  • simplicity
  • speed
  • uniformity
• Used to evaluate periodontal needs on epidemiological studies

What type of examination used:

• The examination use a the CPITN special probe
• Indices record on per sextants
• 6 index teeth 6 ,1, 6

WHO Periodontal examination

Used by WHO for pocket depth and calculus measurement

• Color coding mark indicates pocket depth
• Ball determines subgingival calculus, easy detection

Criterion Of WHO examination:

• 0: Care not required
• 1: Probing causes gum bleeding
• 2: Calculus and some plaque factors exist
• 3: 4-5 mm pockets can be detected
• 6 mm+ pockets can be detected

Criterion from TN index:

0: Treatments are not required. 1: Patient need increase in mouth's hygienic care 2: Pro scaling is needed for mouth hygiene 3: Pockets are deep, scaling and complex procedure necessary

Fluorosis:

• Tooth enamel defect caused by higher intake of fluorides for first 8 yrs in life
• Caused by Fluoridated drinking water, Fluoride tooth paste and or Flu tablets Definition :- Is a developmental disturbance Rather affects tooth appearance

Safe fluoride level:

• safe level is .05 to .07 mgF/Kg
• teeth intake affects composition, results in fluorapatite Symptoms :-
• Tiny white streaks exist
• Brown dark rugged stains
• Uneffected due to fluoride, smooth with glossy teeth
• Pale white creme teeth

Deans index:

• Is used in children and developed during 40's by Trendley Dean as fluoride intake indicator
• Questionable
• Very mild
• Mild
• Moderate
• Sever