When your upper and lower teeth do not align properly when you bite down, this is known as malocclusion, or a “bad bite.” This misalignment is common and affects a significant number of people to varying degrees. While malocclusion can impact the appearance of your smile, it is primarily a functional concern that affects how you chew, speak, and maintain oral health.
Defining the Misalignment: Types of Bite Problems
Malocclusion covers a spectrum of alignment issues defined by how the upper and lower dental arches relate when the mouth is closed. A normal bite, or Class I occlusion, is characterized by the upper teeth slightly overlapping the lower teeth, with the upper molars fitting into the grooves of the lower molars.
One common issue is an overbite, often called a deep bite, where the upper front teeth cover the lower front teeth excessively in a vertical direction. This excessive vertical overlap can cause the lower teeth to bite into the gum tissue behind the upper teeth, potentially leading to tissue damage. Conversely, an underbite, or Class III malocclusion, occurs when the lower teeth and jaw extend horizontally past the upper front teeth. This gives the lower jaw a more prominent appearance and is often the most difficult type to correct without addressing the jaw structure.
A crossbite is a misalignment where one or more upper teeth bite on the inside of the lower teeth, rather than fitting outside them. This can affect the front teeth (anterior crossbite) or the back teeth (posterior crossbite). When there is a space between the upper and lower teeth when the jaw is closed, it is termed an open bite. This gap most often occurs in the front and can interfere with the ability to bite into certain foods or pronounce specific sounds.
Underlying Reasons for Bite Problems
The origins of a misaligned bite are categorized into three main areas: skeletal, dental, and habitual factors. Skeletal factors relate to the size, shape, and relative position of the upper and lower jaws, which are often determined by genetics. A discrepancy in jaw size, such as an underdeveloped lower jaw or an overgrown upper jaw, can cause a significant misalignment present from birth. These inherited factors are the most common cause of malocclusion.
Dental factors involve issues specific to the teeth themselves, independent of the jaw structure. This includes having teeth that are too large or too small for the jawbone, leading to crowding or spacing issues. The premature loss of primary (baby) teeth can also cause permanent teeth to erupt incorrectly or shift into the vacant space. Additionally, the presence of extra or atypically shaped teeth can contribute to a bad bite.
Environmental and habitual factors refer to behaviors that influence the development of the jaw and teeth, particularly during childhood. Prolonged habits like thumb sucking, finger sucking, or extended pacifier use past the age of three can place pressure on the teeth and jaw, altering their growth trajectory. Other habits, such as tongue thrusting or consistent mouth breathing, can also exert forces that contribute to the development of a malocclusion.
Addressing the Problem: Diagnosis and Treatment Options
Addressing a misaligned bite begins with a comprehensive diagnosis from an orthodontist, who specializes in correcting these issues. The process involves a visual examination of the teeth and bite relationship. To determine the underlying cause and severity, the orthodontist uses diagnostic tools like X-rays, which provide images of the jawbone and tooth roots, and dental impressions to create precise models of the teeth.
The treatment plan is individualized and depends on the type and severity of the malocclusion, as well as the patient’s age. For most cases, the primary non-surgical solution is orthodontic treatment using appliances that apply gentle, continuous pressure to shift the teeth into their correct positions. Traditional metal braces use brackets and wires, while clear aligners offer a less noticeable option through a series of custom-made, removable trays. Treatment can also involve appliances like palate expanders or elastics to correct the relationship between the upper and lower jaws.
For severe skeletal discrepancies, where the jawbones are significantly misaligned, a combination of orthodontics and orthognathic surgery may be required. This surgical intervention repositions the jawbones to achieve proper alignment before the teeth are fine-tuned. Untreated malocclusion can lead to complications such as uneven wear on the teeth, difficulty chewing, speech impediments, and chronic jaw pain related to the temporomandibular joint (TMJ).