Related Experiment Video
Updated: May 5, 2026
A Postoperative Evaluation Guideline for Computer-Assisted Reconstruction of the Mandible
Published on: January 28, 2020
Bolton's ratio variations in Angle's Class I, Class II and Class III malocclusions: An observational study
Pinaki Roy1, Poulomi Roy2, Sourav Koley3
1Associate Professor, Dept. of Orthodontics and Dentofacial Orthopaedics, Burdwan Dental College & Hospital, Burdwan.
Background:
The aim of this study was to compare Bolton's Overall and Anterior ratio in different types of malocclusions.
Material And Methods:
105 study cast were taken from the patients undergoing orthodontic treatment and they were divided into three classes based on molar relation, i.e. Angle's Class I (n = 35), Angle's Class II (n = 35) and Angle's Class III (n = 35) according to the Angle's classification of malocclusion. The mesio-distal widths of all maxillary and mandibular teeth from right first molar to left first molar were measured with a digital calliper. The findings were then used to calculate the anterior and total Bolton's ratios. Statistical analysis was done using ANOVA and Tukey's test.
Results:
The mean total ratio for the whole sample was 91.4±3.33, which is very close to Bolton's proposed ideal ratio. The anterior ratio for the whole sample was found to be 77.4±9.02, which is also similar Bolton's proposed ideal ratio. In Class I patients, the mean total ratio calculated was 91.2 ± 2.69, that is close to Bolton's proposed ideal ration and the mean anterior ratio calculated was 79.2±3.78, which is greater than Bolton's proposed ratio that signify increased mesio-distal width in mandibular anterior segment. The total mean ratio calculated for Class II was 91.1 ± 3.44) and for Class III patients was 92±3.77. The anterior mean ratio for class III patients was 78.6±5.24 and for Class II patients was 76.8± 5.28 which indicates higher anterior ration for class III patients and lower anterior ratio for class II patients compared to Bolton's ideal ratio that signifies mandibular anterior tooth material excess in Class III patients and maxillary anterior tooth material excess in class II cases.
Conclusions:
In this study population there was increased mesio-distal width in mandibular anterior segment in patients with Class I and Class III malocclusion. Also, there is maxillary anterior tooth material excess in Class II patients. Key words:Angle's classification, Anterior ratio , Bolton's Ratio , Inter-arch relationship, Overall ratio.
Related Concept Videos
01:09Functional Classification of Joints
The functional classification of joints is determined by the amount of mobility between the adjacent bones. Joints are functionally classified as a synarthrosis or immobile joint, an amphiarthrosis or slightly moveable joint, or as a diarthrosis, a freely moveable joint. Fibrous and cartilaginous joints can be functionally classified as either synarthroses or amphiarthroses, whereas all synovial joints are classified as diarthroses.
Synarthrosis
An...
01:28Angle Closure Glaucoma: Treatment
01:15Unsymmetric Bending - Angle of Neutral Axis
When a bending moment is applied at an angle θ concerning the vertical axis of a symmetrical member, it can be resolved into components along the member's principal...
01:12General Case of Eccentric Axial Loading
Consider a member subjected to equal and opposite forces that are applied along a line that does not coincide with the member's neutral axis. In unsymmetrical...