Space Analysis Calculator
Perform Bolton ratio analysis and arch length discrepancy measurement for orthodontic treatment planning.
Inputs
mm
mm
mm
mm
mm
mm
Results
Bolton Overall Ratio (%)
91.21%
Bolton Anterior Ratio (%)77.08%
Overall Deviation from Ideal (%)-0.09
Anterior Deviation from Ideal (%)-0.12
Overall Tooth Size Excess (mm)-0.1
Anterior Tooth Size Excess (mm)-0.1
Arch Length Discrepancy (mm)-5
Crowding ClassificationModerate Crowding
Overall SignificantNo
Anterior SignificantNo
How to Use This Calculator
- Measure and enter tooth widths (mm) for each tooth in the arch using a Boley gauge or digital calipers.
- Enter arch length (mm) measured along the dental arch from first molar to first molar.
- Read arch length discrepancy (mm): negative = crowding, positive = spacing.
- Use Bolton analysis outputs to identify tooth size discrepancies between maxillary and mandibular arches.
- Incorporate space analysis into extraction decision-making alongside cephalometric and facial evaluation.
How the result changes with Maxillary 12 Tooth Sum (mm)
| Maxillary 12 Tooth Sum (mm) | Bolton Overall Ratio (%) |
|---|---|
| 13 | 638.46% |
| 46 | 180.43% |
| 85 | 97.65% |
| 117 | 70.94% |
What each input means
- Mandibular 12 Tooth Sum (mm)
- Sum of mesiodistal widths of all 12 mandibular teeth (1st molar to 1st molar).
- Maxillary 12 Tooth Sum (mm)
- Sum of mesiodistal widths of all 12 maxillary teeth (1st molar to 1st molar).
- Mandibular Anterior 6 Sum (mm)
- Sum of mesiodistal widths of 6 mandibular anterior teeth (canine to canine).
- Maxillary Anterior 6 Sum (mm)
- Sum of mesiodistal widths of 6 maxillary anterior teeth (canine to canine).
- Arch Perimeter Available (mm)
- Available arch length measured along the arch form.
- Total Tooth Width Sum (mm)
- Sum of mesiodistal widths of all teeth in the arch being analyzed.
What each result means
- Bolton Overall Ratio (%)
- Mandibular 12 / Maxillary 12 * 100. Ideal = 91.3% (+/- 1.91).
- Bolton Anterior Ratio (%)
- Mandibular anterior 6 / Maxillary anterior 6 * 100. Ideal = 77.2% (+/- 1.65).
- Overall Deviation from Ideal (%)
- Difference from ideal 91.3%. Positive = relative mandibular excess.
- Anterior Deviation from Ideal (%)
- Difference from ideal 77.2%. Positive = relative mandibular excess.
- Overall Tooth Size Excess (mm)
- Positive = mandibular tooth material excess; Negative = maxillary excess.
- Anterior Tooth Size Excess (mm)
- Anterior Bolton discrepancy in mm.
- Arch Length Discrepancy (mm)
- Arch perimeter minus tooth width sum. Negative = crowding, Positive = spacing.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersMandibular 12 Tooth Sum (mm) = 83, Maxillary 12 Tooth Sum (mm) = 91, Mandibular Anterior 6 Sum (mm) = 37, Maxillary Anterior 6 Sum (mm) = 48 = 6 input(s) provided
- Calculate Bolton Overall RatioBolton Overall Ratio91.21 = 91.21%
- Calculate Bolton Anterior RatioBolton Anterior Ratio77.08 = 77.08%
- Calculate Overall Deviation from IdealOverall Deviation from Ideal-0.09 = -0.09
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