dentures dentures dentures (also known as false teeth) are prosthetic devices constructed to replace missing teeth, supported by the surrounding soft and hard tissues of the oral cavity. conventional dentures are removable (removable partial denture or complete denture). however, there are many denture designs, some which rely on bonding or clasping onto teeth or dental implants (fixed prosthodontics). there are two main categories of dentures, the distinction being whether they fit onto the mandibular arch or on the maxillary arch. denturesa maxillary denturemeshd003778 occlusal view of the same maxillary denture medical uses dentures can help people via: mastication: chewing ability is improved by the replacement of edentulous (lacking teeth) areas with denture teeth. aesthetics: the presence of teeth gives a natural appearance to the face, and wearing a denture to replace missing teeth provides support for the lips and cheeks and corrects the collapsed appearance that results from the loss of teeth. pronunciation: replacing missing teeth, especially the anteriors, enables patients to speak better, enunciating more easily sibilants and fricatives in particular. self-esteem: improved looks and speech boost confidence in patients' ability to interact socially. complications stomatitis denture stomatitis is an inflammatory condition of the skin under the dentures. it can affect both partial and complete denture wearers, and is most commonly seen on the palatal mucosa. clinically, it appears as simple localized inflammation (type i), generalized erythema covering the denture-bearing area (type ii) and inflammatory papillary hyperplasia (type iii). people with denture stomatitis are more likely to have angular cheilitis. denture stomatitis is caused by a mixed infection of candida albicans (90%) and a number of bacteria such as staphylococcus, streptococcus, fusobacterium and bacteroides species. acrylic resin is more susceptible for fungal colonization, adherence and proliferation. denture trauma, poor denture hygiene and nocturnal denture wear are local risk factors for denture stomatitis. systemic risk factors for denture stomatitis include nutritional deficiencies, immunosuppression, smoking, diabetes, use of steroid inhaler and xerostomia. a person should be investigated for any underlying systemic disease. improve the fit of ill-fitting dentures to eliminate any dental trauma. stress on the importance of good denture hygiene including cleaning of the denture, soaking the dentures in disinfectant solution and not wearing it during sleeping at night is the key to treat all types of denture stomatitis. topical application and systemic use of antifungal agents can be used to treat denture stomatitis cases that fail to respond to local conservative measures. ulceration mouth ulceration is the most common lesion in people with dentures. it can be caused by repetitive minor trauma like poorly fitting dentures including over-extension of a denture. pressure-indicating paste can be used to check the fitting of dentures. it allows the areas of premature contact to be distinguished from areas of physiologic tissue contact. therefore, the particular area can be polished with an acrylic bur. leaching of residual monomer methyl methacrylate from inadequately cured denture acrylic resin material can cause mucosal irritation and hence oral ulceration as well. patients are advised to use warm salt water mouth rinses and a betamethasone rinse can heal ulcer. review of persisting oral ulcerations for more than 3 weeks is recommended. tooth loss people can become entirely edentulous for many reasons, the most prevalent being removal due to dental disease, which typically relates to oral flora control, i.e., periodontal disease and tooth decay. other reasons include pregnancy, tooth developmental defects caused by severe malnutrition, genetic defects such as dentinogenesis imperfecta, trauma, or drug use. periodontitis is defined as an inflammatory lesion mediated by host-pathogen interaction that results in the loss of connective tissue fiber attachment to the root surface and ultimately to the alveolar bone. it is the loss of connective tissue to the root surface that leads to teeth falling out. the hormones associated with pregnancy increases the risk of gingivitis and vomiting. hormones released during pregnancy softens the cardia muscle ring that keeps food within the stomach. hydrochloric acid is the acid involved in gastric reflux, also known as morning sickness. this acid, at a ph of 1.5-3.5, coats the enamel on the teeth, mainly affecting the palatal surfaces of the maxillary teeth. eventually the enamel is softened and easily wears away. dental trauma refers to trauma (injury) to the teeth and/or periodontium (gums, periodontal ligament, alveolar bone). strong force may cause the root of the tooth to completely dislocate from its socket, mild trauma may cause the tooth to chip. types vending of dentures in marrakesh (morocco). removable partial dentures removable partial dentures are for patients who are missing some of their teeth on a particular arch. fixed partial dentures, also known as "crown and bridge" dentures, are made from crowns that are fitted on the remaining teeth. they act as abutments and pontics, and are made from materials resembling the missing teeth. fixed bridges are more expensive than removable appliances but are more stable. another option in this category is the flexible partial, which takes advantage of innovations in digital technology. flexible partial fabrication involves only non-invasive procedures. dentures can be difficult to clean and can affect oral hygiene. complete dentures complete dentures are worn by patients who are missing all of the teeth in a single arch—i.e. the maxillary (upper) or mandibular (lower) arch—or, more commonly, in both arches. the full denture is removable because it is held in place by suction. they are painful at first and can take some time to get used to. there are two types of full dentures: immediate dentures and conventional dentures. copy dentures copy dentures can be made for either partial, but mainly complete denture patients. these dentures require fewer visits to make and usually are made for older patients, patients who would have difficulty adjusting to new dentures, would like a spare pair of dentures or like the aesthetics of their dentures already. this requires taking an impression of the patient's current denture and remaking it. materials dentures are mainly made from acrylic due to the ease of material manipulation and likeness to intra-oral tissues, i.e. gums. most dentures are composed of heat-cured acrylic polymethyl methacrylate and rubber-reinforced polymethyl methacrylate. coloring agents and synthetic fibers are added to obtain the tissue-like shade, and to mimic the small capillaries of the oral mucosa, respectively. however, dentures made from acrylic can be fragile and fracture easily if the patient has trouble adapting neuromuscular control. this can be overcome by reinforcing the denture base with cobalt chromium (co-cr). they are often thinner (therefore more comfortable) and stronger (to prevent repeating fractures). history main article: history of dental treatments § dentures carved ivory dentures from the 18th century. left is lower/mandibular; upper/maxillary is at right. pierre fauchard described the construction of dentures using a metal frame, animal bone teeth, and leaf springs in 1728. as early as the 7th century bc, etruscans in northern italy made partial dentures out of human or other animal teeth fastened together with gold bands. the romans had likely borrowed this technique by the 5th century bc. wooden full dentures were invented in japan around the early 16th century. softened beeswax was inserted into the patient's mouth to create an impression, which was then filled with harder bees wax. wooden dentures were then meticulously carved based on that model. the earliest of these dentures were entirely wooden, but later versions used natural human teeth or sculpted pagodite, ivory, or animal horn for the teeth. these dentures were built with a broad base, exploiting the principles of adhesion to stay in place. this was an advanced technique for the era; it would not be replicated in the west until the late 18th century. wooden dentures continued to be used in japan until the opening of japan to the west in the 19th century. in 1728, pierre fauchard described the construction of dentures using a metal frame and teeth sculpted from animal bone. the first porcelain dentures were made around 1770 by alexis duchâteau. in 1791, the first british patent was granted to nicholas dubois de chemant, previous assistant to duchateau, for "de chemant's specification": ... a composition for the purpose of making of artificial teeth either single double or in rows or in complete sets, and also springs for fastening or affixing the same in a more easy and effectual manner than any hitherto discovered which said teeth may be made of any shade or colour, which they will retain for any length of time and will consequently more perfectly resemble the natural teeth. he began selling his wares in 1792, with most of his porcelain paste supplied by wedgwood. 17th century london's peter de la roche is believed to be one of the first 'operators for the teeth', men who advertized themselves as specialists in dental work. they were often professional goldsmiths, ivory turners or students of barber-surgeons. in 1820, samuel stockton, a goldsmith by trade, began manufacturing high-quality porcelain dentures mounted on 18-carat gold plates. later dentures from the 1850s onwards were made of vulcanite, a form of hardened rubber into which porcelain teeth were set. in the 20th century, acrylic resin and other plastics were used. in britain, sequential adult dental health surveys revealed that in 1968 79% of those aged 65–74 had no natural teeth; by 1998, this proportion had fallen to 36%. george washington george washington (1732–1799) suffered from problems with his teeth throughout his life, and historians have tracked his experiences in great detail. he lost his first adult tooth when he was twenty-two and had only one left by the time he became president. he had several sets of false teeth made, four of them by a dentist named john greenwood. none of the sets, contrary to popular belief, were made from wood or contained any wood. the set made when he became president were carved from hippopotamus and elephant ivory, held together with gold springs. prior to these, he had a set made with real human teeth, likely ones he purchased from "several unnamed negroes, presumably mount vernon slaves" in 1784. manufacturing modern dentures are most often fabricated in a commercial dental laboratory or by a denturist using a combination of tissue shaded powders polymethyl methacrylate acrylic (pmma). these acrylics are available as heat-ccured or cold-cured types. commercially produced acrylic teeth are widely available in hundreds of shapes and tooth colors. the process of fabricating a denture usually begins with an initial dental impression of the maxillary and mandibular ridges. standard impression materials are used during the process. the initial impression is used to create a simple stone model that represents the maxillary and mandibular arches of the patient's mouth. this is not a detailed impression at this stage. once the initial impression is taken, the stone model is used to create a 'custom impression tray', which is then used to take a second and much more detailed and accurate impression of the patient's maxillary and mandibular ridges. polyvinyl siloxane impression material is one of several very accurate impression materials used when the final impression is taken of the maxillary and mandibular ridges. a wax rim is fabricated to assist the dentist or denturist in establishing the vertical dimension of occlusion. after this, a bite registration is created to marry the position of one arch to the other. once the relative position of each arch to the other is known, the wax rim can be used as a base to place the selected denture teeth in correct position. this arrangement of teeth is tested in the mouth so that adjustments can be made to the occlusion. after the occlusion has been verified by the dentist or denturist and the patient, and all phonetic requirements are met, the denture is processed. processing a denture is usually performed using a lost-wax technique whereby the form of the final denture, including the acrylic denture teeth, is invested in stone. this investment is then heated, and when it melts the wax is removed through a spruing channel. the remaining cavity is then either filled by forced injection or pouring in the uncured denture acrylic, which is either a heat-cured or cold-cured type. during the processing period, heat cured acrylics—also called permanent denture acrylics—go through a process called polymerization, causing the acrylic materials to bond very tightly and taking several hours to complete. after a curing period, the stone investment is