Little Irregularity Index Calculator

Littlefive-contact mandibular anterior irregularity linear displacement sum, not arch-length shortage, overall malocclusion or treatment need. Actual contact landmarks and measurement independently assessed.

Description

Little's irregularity index sums five anterior contact-point displacements in millimeters.

Little's irregularity index sums five anterior contact-point displacements in millimeters.^[1]

The landmarks must be independently measured under the intended mandibular convention. Use this tool to calculate the stated observation or conditional model from supplied measurements.

When to use Little Irregularity Index Calculator

Use this tool to calculate the stated observation or conditional model from supplied measurements. Establish the qualified examination or measurement context, matching instrument/protocol edition, site order and units.

How to use Little Irregularity Index Calculator and understand its results

Establish the qualified examination or measurement context, matching instrument/protocol edition, site order and units.
Enter independentlyMeasuredFiveMandibularContactDisplacementsMm, using the field meanings and rules below, then run the tool.
Read result.observedLittleIrregularityIndexMm. Interpret each field using the units, signs and evidence rules below.
If input validation fails, correct the reported field and run again. Before applying a successful result, check the stated reference scope, units, assumptions and any retained unknown evidence.

Input field	Meaning	Value type	Requirement
independentlyMeasuredFiveMandibularContactDisplacementsMm	Independently measured five mandibular contact displacements mm	list of number	Required

Require exactly five nonnegative finite mandibular contact displacement measurements in millimeters. Sum them without choosing landmarks, rounding or assigning severity.

LittleIrregularityIndexMm=ΣfiveContactDisplacementsMm

Apply the field units and exact ordering, boundary and evidence rules above.

Output field	Meaning	Value type
result	Structured result containing the calculation or selected reference fields below	object
result.observedLittleIrregularityIndexMm	Observed Little Irregularity Index Mm; use the units, sign convention and calculation stated above	number

json

{
  "input": {
    "independentlyMeasuredFiveMandibularContactDisplacementsMm": [
      1,
      2,
      0,
      1,
      1
    ]
  },
  "output": {
    "result": {
      "observedLittleIrregularityIndexMm": 5
    }
  }
}

Limitations and assumptions

The landmarks must be independently measured under the intended mandibular convention. Results depend on the independently established measurement basis and the exact model assumptions above.

Every listed input requires an explicit value. Unexpected fields, incorrect value types, nonfinite numbers and sparse numeric arrays fail validation; tool-specific bounds and alignment rules apply as described above. Extremely large inputs or outputs can also be rejected. An input error is distinct from a successful calculation that reports a false comparison or retains unknown evidence.

Alternative or Complementary methods

Use Bolton Arch Length Discrepancy Calculator to examine a related aspect: Arch space discrepancy compares available perimeter with the summed tooth widths needed on the same basis.

Use Bolton Anterior Ratio Calculator where its separate inputs and scope apply: Bolton's anterior ratio compares six matched tooth widths per arch.

References

Little Irregularity Index Calculator — tool.io

Similar or alternative tools

Bolton Arch Length Discrepancy Calculator
Arch space discrepancy compares available perimeter with the summed tooth widths needed on the same basis.
Bolton Anterior Ratio Calculator
Bolton's anterior ratio compares six matched tooth widths per arch.