In dentistry, the neutral zone refers to that space in the oral cavity where the forces exerted by the musculature of the tongue are equal and balanced with the forces exerted by the buccinator muscle of the cheek laterally and the orbicularis oris muscle anteriorly. [1] [2]
In other words, it is the potential space between the lips and cheeks on one side and the tongue on the other; where the forces between the two are equal. Other synonyms include: zone of equilibrium, zone of minimal conflict, potential denture space and dead space. It is in this zone that the natural dentition lie, and this is where artificial teeth of complete dentures should be positioned. Complete dentures that are constructed in this way exhibit enhanced stability, retention and comfort.
The neutral zone is an important concept in prosthodontics, because prosthetic teeth generally must conform to the horizontal position determined by the neutral zone. Prostheses which set teeth outside this zone risk problems such as discomfort, cheek or tongue biting, and instability of the denture.
The neutral zone is also important in orthodontics. Moving teeth outside of this zone means that the muscular forces on the teeth will be out of balance in one direction, and tend to be more likely to relapse to their original position.
The neutral zone technique is indicated in cases where there has been:
Advantages of constructing a denture within the neutral zone include:
Disadvantages include:
Dentures are prosthetic devices constructed to replace missing teeth, and are supported by the surrounding soft and hard tissues of the oral cavity. Conventional dentures are removable. However, there are many denture designs, some which rely on bonding or clasping onto teeth or dental implants. There are two main categories of dentures, the distinction being whether they are used to replace missing teeth on the mandibular arch or on the maxillary arch.
A bridge is a fixed dental restoration used to replace one or more missing teeth by joining an artificial tooth definitively to adjacent teeth or dental implants.
A dental technologist is a member of the dental team who, upon prescription from a dental clinician, constructs custom-made restorative and dental appliances.
A dental implant is a prosthesis that interfaces with the bone of the jaw or skull to support a dental prosthesis such as a crown, bridge, denture, or facial prosthesis or to act as an orthodontic anchor. The basis for modern dental implants is a biologic process called osseointegration, in which materials such as titanium or zirconia form an intimate bond to bone. The implant fixture is first placed so that it is likely to osseointegrate, then a dental prosthetic is added. A variable amount of healing time is required for osseointegration before either the dental prosthetic is attached to the implant or an abutment is placed which will hold a dental prosthetic/crown.
Prosthodontics, also known as dental prosthetics or prosthetic dentistry, is the area of dentistry that focuses on dental prostheses. It is one of 12 dental specialties recognized by the American Dental Association (ADA), Royal College of Surgeons of England, Royal College of Surgeons of Edinburgh, Royal College of Surgeons of Ireland, Royal College of Surgeons of Glasgow, Royal College of Dentists of Canada, and Royal Australasian College of Dental Surgeons. The ADA defines it as "the dental specialty pertaining to the diagnosis, treatment planning, rehabilitation and maintenance of the oral function, comfort, appearance and health of patients with clinical conditions associated with missing or deficient teeth or oral and maxillofacial tissues using biocompatible substitutes."
A removable partial denture (RPD) is a denture for a partially edentulous patient who desires to have replacement teeth for functional or aesthetic reasons and who cannot have a bridge for any reason, such as a lack of required teeth to serve as support for a bridge or financial limitations.
Geriatric dentistry is the delivery of dental care to older adults involving diagnosis, prevention, management and treatment of problems associated with age related diseases. The mouth is referred to as a mirror of overall health, reinforcing that oral health is an integral part of general health. In the elderly population poor oral health has been considered a risk factor for general health problems. Older adults are more susceptible to oral conditions or diseases due to an increase in chronic conditions and physical/mental disabilities. Thus, the elderly form a distinct group in terms of provision of care.
The oral mucosa is the mucous membrane lining the inside of the mouth. It comprises stratified squamous epithelium, termed "oral epithelium", and an underlying connective tissue termed lamina propria. The oral cavity has sometimes been described as a mirror that reflects the health of the individual. Changes indicative of disease are seen as alterations in the oral mucosa lining the mouth, which can reveal systemic conditions, such as diabetes or vitamin deficiency, or the local effects of chronic tobacco or alcohol use. The oral mucosa tends to heal faster and with less scar formation compared to the skin. The underlying mechanism remains unknown, but research suggests that extracellular vesicles might be involved.
The vestibular lamina is responsible for the formation of the vestibule and arises from a group of cells called the primary epithelial band. This band is created at about 37 days of development in utero. The vestibular lamina forms shortly after the dental lamina and is positioned right in front of it. The vestibule is formed by the proliferation of the vestibular lamina into the ectomesenchyme. The vestibular lamina is usually contrasted with the dental lamina, which develops concurrently and is involved with developing teeth. Both the vestibular lamina and the dental lamina arise from a group of epithelial cells, called the primary epithelial band.
Epulis fissuratum is a benign hyperplasia of fibrous connective tissue which develops as a reactive lesion to chronic mechanical irritation produced by the flange of a poorly fitting denture. More simply, epulis fissuratum is where excess folds of firm tissue form inside the mouth, as a result of rubbing on the edge of dentures that do not fit well. It is a harmless condition and does not represent oral cancer. Treatment is by simple surgical removal of the lesion, and also by adjustment of the denture or provision of a new denture.
A dental emergency is an issue involving the teeth and supporting tissues that are of high importance to be treated by the relevant professional. Dental emergencies do not always involve pain, although this is a common signal that something needs to be looked at. Pain can originate from the tooth, surrounding tissues or can have the sensation of originating in the teeth but be caused by an independent source. Depending on the type of pain experienced an experienced clinician can determine the likely cause and can treat the issue as each tissue type gives different messages in a dental emergency.
Toothlessness, or edentulism, is the condition of having no teeth. In organisms that naturally have teeth, it is the result of tooth loss.
A dental impression is a negative imprint of hard (teeth) and soft tissues in the mouth from which a positive reproduction can be formed. It is made by placing an appropriate material in a stock or custom dental impression tray which is designed to roughly fit over the dental arches. Impression material is of liquid or semi-solid nature when first mixed and placed in the mouth. It then sets to become an elastic solid, leaving an imprint of person's dentition and surrounding structures of oral cavity.
A denturist in the United States and Canada, clinical dental technologist in the United Kingdom and Ireland, dental prosthetist in Australia, or a clinical dental technician in New Zealand is a member of the oral health care team and role as primary oral health care provider who provides an oral health examination, planning treatment, takes impressions of the surrounding oral tissues, constructs and delivers removable oral prosthesis treatment directly to the patient.
Occlusion, in a dental context, means simply the contact between teeth. More technically, it is the relationship between the maxillary (upper) and mandibular (lower) teeth when they approach each other, as occurs during chewing or at rest.
In human anatomy, the mouth is the first portion of the alimentary canal that receives food and produces saliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth.
Alveoloplasty is a surgical pre-prosthetic procedure performed to facilitate removal of teeth, and smoothen or reshape the jawbone for prosthetic and cosmetic purposes. In this procedure, the bony edges of the alveolar ridge and its surrounding structures is made smooth, redesigned or recontoured so that a well-fitting, comfortable, and esthetic prosthesis may be fabricated or implants may be surgically inserted. This pre-prosthetic surgery which may include bone grafting prepares the mouth to receive a prosthesis or implants by improving the condition and quality of the supporting structures so they can provide support, better retention and stability to the prosthesis.
A complete denture is a removable appliance used when all teeth within a jaw have been lost and need to be prosthetically replaced. In contrast to a partial denture, a complete denture is constructed when there are no more teeth left in an arch, hence it is an exclusively tissue-supported prosthesis. A complete denture can be opposed by natural dentition, a partial or complete denture, fixed appliances or, sometimes, soft tissues.
Overdenture is any removable dental prosthesis that covers and rests on one or more remaining natural teeth, the roots of natural teeth, and/or dental implants. It is one of the most practical measures used in preventive dentistry. Overdentures can be either tooth supported or implant supported. It is found to help in the preservation of alveolar bone and delay the process of complete edentulism.
Occlusion according to The Glossary of Prosthodontic Terms Ninth Edition is defined as 'the static relationship between the incising or masticating surfaces of the maxillary or mandibular teeth or tooth analogues'.