Overall Ratio
Uses 12-tooth sums to evaluate full-arch size discrepancy.
Why this page exists
Bolton analysis helps estimate maxillary or mandibular tooth-size excess. This page gives a practical flow for quick calculations and communication.
Anterior Ratio
Uses the middle 6 anterior teeth for smile-zone proportional analysis.
Ideal vs Actual
Shows ideal counterpart values and absolute differences in millimeters.
Read Scientific Foundation & Bolton's Methodology
Scientific Foundation: The Bolton Legacy
A mathematical standard that remains the cornerstone of modern orthodontic diagnosis.
The 1958 Study: Establishing the Gold Standard
In his seminal 1958 research, "Disharmony in tooth size and its relation to the analysis and treatment of malocclusion," Wayne A. Bolton conducted a meticulous analysis of 55 cases with exceptional, untreated occlusion. By measuring the mesiodistal widths of the permanent dentition, he identified two constant mathematical relationships required for optimal intercuspation:
- The Overall Ratio (91.3%): A comparison of the 12 mandibular teeth to the 12 maxillary teeth (first molar to first molar), representing total arch coordination.
- The Anterior Ratio (77.2%): A comparison of the 6 mandibular anterior teeth to the 6 maxillary anterior teeth, critical for establishing proper overjet and overbite.
The 1962 Application: From Data to Diagnosis
Bolton’s 1962 follow-up study bridged the gap between academic research and clinical chairside practice. He demonstrated that a significant Tooth-Size Discrepancy (TSD)—exceeding one or two standard deviations—precludes the achievement of a stable Class I relationship. Whether managing maxillary lateral incisor microdontia (peg laterals) or mandibular dental excess, the Bolton analysis provides the objective roadmap for deciding between interproximal reduction (IPR), extractions, or restorative build-ups.
How it works
- Enter all mesiodistal widths for maxillary and mandibular arches.
- Review auto-calculated sums for 12-tooth and anterior 6-tooth groups.
- Interpret ratio status and ideal/actual differences for treatment planning support.
Patient Details
Mesiodistal Tooth Sizes (mm)
Filled: 0 / 24
Enter right-to-left values for each arch. Anterior sum uses the middle 6 teeth in each row.
Potential Microdontia / Peg Lateral
Potential Macrodontia
| Arch | 6R | 5R | 4R | 3R | 2R | 1R | 1L | 2L | 3L | 4L | 5L | 6L |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Maxillary | ||||||||||||
| Mandibular |
Clinical Diagnostic Assistant
Use this questionnaire to determine if the discrepancy is due to tooth-size excess or arch-size deficiency.
Diagnostic Questionnaire
1. Are any teeth abnormally small (e.g., Peg Laterals)?
2. Are any teeth missing or impacted?
3. Where is the unexplained spacing/crowding?
4. Desired treatment approach?
Average Tooth Sizes (G.V. Black)
Data source: "Descriptive Anatomy of the Human Teeth" (G.V. Black, 1902). Based on a comprehensive study of North American Caucasian populations to establish normative dental dimensions.
| Tooth | Max (mm) | Mand (mm) |
|---|---|---|
| Central (1) | 8.5 | 5.0 |
| Lateral (2) | 6.5 | 5.5 |
| Canine (3) | 7.5 | 7.0 |
| 1st Premolar (4) | 7.0 | 7.0 |
| 2nd Premolar (5) | 7.0 | 7.0 |
| 1st Molar (6) | 10.5 | 11.0 |
Note: Modern studies (e.g., Moyers, 1988) show slight variations across diverse ethnic groups. Use as a clinical baseline.
View Original Text (1902)Final Diagnostic Conclusion
Complete the analysis and questionnaire for a clinical conclusion.
Visual Discrepancy Synthesis
Enter all values to generate clinical summary.
View Technical Bolton Ratios & Millimeter Data
Overall Ratio
-- %
Enter values to calculate.
Actual Mand 12
-- mm
Ideal Mand 12
-- mm
Diff
-- mm
Actual Max 12
-- mm
Ideal Max 12
-- mm
Diff
-- mm
Anterior Ratio
-- %
Enter values to calculate.
Actual Mand 6
-- mm
Ideal Mand 6
-- mm
Diff
-- mm
Actual Max 6
-- mm
Ideal Max 6
-- mm
Diff
-- mm
Reference means: Overall 91.3%, Anterior 77.2%.
References & Acknowledgment
Analysis based on the pioneering work of Wayne A. Bolton.
Bolton, W. A. (1958). Disharmony in tooth size and its relation to the analysis and treatment of malocclusion. The Angle Orthodontist, 28(3), 113–130.
Read Original Article (1958)Bolton, W. A. (1962). The clinical application of a tooth-size analysis. American Journal of Orthodontics, 48(7), 504–529.
Read Original Article (1962)Acknowledgment: We credit the mathematical foundations of this tool to the late Wayne A. Bolton, whose research defined the standard ratios for diagnosing tooth-size discrepancies in orthodontics.
Trusted by clinicians
The same practical, fast workflow style used across ZenaraMed tools.
"This makes Bolton chairside discussion straightforward for patients and team."
"The ideal vs actual output is exactly what I need during treatment planning."