Vertical Dimension: Open Bite and Deep Bite

The vertical plane of occlusion describes how much the upper and lower incisors overlap when the back teeth meet. Two opposite deviations define this dimension: open bite, where the incisors fail to overlap and a vertical gap remains, and deep bite, where the overlap is excessive. Both can be dental or skeletal in origin and are described separately from the anteroposterior Angle class.

Definition

In the vertical dimension, overbite is the degree of vertical overlap of the lower incisors by the upper incisors. An anterior open bite is a lack of vertical overlap leaving a gap between the incisor edges when the posterior teeth are in occlusion; a deep bite (deep overbite) is an excessive vertical overlap of the incisors.

Scope

The entry covers the vertical relationship of the dental arches, the definitions of open bite and deep bite, the distinction between their dental and skeletal forms, and the functional and growth-related factors associated with them. It is a descriptive concept and does not provide treatment guidance.

Core questions

• What distinguishes the vertical dimension of occlusion from the anteroposterior dimension?
• How do open bite and deep bite differ, and how is each defined?
• When is a vertical discrepancy dental versus skeletal in origin?
• What functional and growth factors are associated with open and deep bites?

Key concepts

• Overbite (vertical incisor overlap)
• Anterior open bite
• Deep bite / deep overbite
• Dental versus skeletal vertical discrepancy
• Facial height and mandibular plane angle
• Habit and soft-tissue influences on the vertical relationship

Mechanisms

Overbite reflects the balance between the eruption of anterior and posterior teeth and the underlying vertical proportions of the face. An anterior open bite can be dental — for example where habits or tongue posture impede incisor eruption — or skeletal, associated with a steep mandibular plane and increased lower facial height; the review literature distinguishes these forms by their morphology and associated factors (Mizrahi, 1978). A deep bite, conversely, reflects excessive incisor overlap that may accompany reduced lower facial height or specific incisor inclinations, as seen in some Class II Division 2 patterns. Because the vertical relationship is independent of the sagittal molar relationship, it is recorded as a separate axis in modern diagnosis (Mizrahi, 1978; Proffit et al., 2018).

Clinical relevance

The vertical dimension is one of the planes of space a clinician characterizes when describing a malocclusion, and recognizing whether an open or deep bite is dental or skeletal informs how the finding is interpreted. This entry is reference material on the vertical relationship and does not direct individual diagnosis or treatment.

Epidemiology

Vertical anomalies are less common than alignment problems but occur across populations; a systematic review of global malocclusion traits reported open bite and deep bite among the vertical features that vary in frequency by region and age group (Alhammadi et al., 2018).

History

As cephalometric analysis matured through the twentieth century, the vertical dimension came to be assessed alongside the anteroposterior one, with facial height and the mandibular plane angle used to separate skeletal from dental forms of open and deep bite. Review articles such as Mizrahi's 1978 survey of anterior open bite consolidated the morphological and etiologic understanding of these vertical patterns (Mizrahi, 1978; Proffit et al., 2018).

Key figures

• William Proffit

Seminal works

• mizrahi-1978

Frequently asked questions

What is the difference between open bite and deep bite?

Open bite is a lack of vertical overlap of the front teeth, leaving a gap when the back teeth meet, while deep bite is an excessive vertical overlap of the upper over the lower incisors.

Is an open bite always skeletal?

No. An anterior open bite may be dental, related to factors that impede incisor eruption, or skeletal, associated with increased lower facial height and a steep mandibular plane.