removed, the acrylic is polished, and the denture is complete. the end result is a denture that looks much more natural, is much stronger and more durable than a cold-cured temporary denture, resists stains and odors, and will last for many years. cold-cured or cold-pour dentures, also known as temporary dentures, do not look as natural, are less durable, tend to be highly porous and are only used as a temporary expedient until a more permanent solution is found. these types of dentures tend to cost much less due to their quick production time (usually minutes) and composition of low-cost materials. it is not suggested that a patient wear a cold-cured denture for a long period of time, as they are prone to cracks and can break rather easily. prosthodontic principles support support is the principle that describes how well the underlying mucosa (oral tissues, including gums) keeps the denture from moving vertically towards the arch in question during chewing, and thus being excessively depressed and moving deeper into the arch. for the mandibular arch, this function is provided primarily by the buccal shelf, a region extending laterally from the back or posterior ridges, and by the pear-shaped pad (the most posterior area of keratinized gingival formed by the scaling down of the retro-molar papilla after the extraction of the last molar tooth). secondary support for the complete mandibular denture is provided by the alveolar ridge crest. the maxillary arch receives primary support from the horizontal hard palate and the posterior alveolar ridge crest. the larger the denture flanges (that part of the denture that extends into the vestibule), the better the stability (another parameter to assess fit of a complete denture). long flanges beyond the functional depth of the sulcus are a common error in denture construction, often (but not always) leading to movement in function, and ulcerations (denture sore spots). stability stability is the principle that describes how well the denture base is prevented from moving in a horizontal plane, and thus sliding from side to side or front to back. the more the denture base (pink material) is in smooth and continuous contact with the edentulous ridge (the hill upon which the teeth used to reside, but now only residual alveolar bone with overlying mucosa), the better the stability. of course, the higher and broader the ridge, the better the stability will be, but this is usually a result of patient anatomy, barring surgical intervention (bone grafts, etc.). retention retention is the principle that describes how well the denture is prevented from moving vertically in the opposite direction of insertion. the better the topographical mimicry of the intaglio (interior) surface of the denture base to the surface of the underlying mucosa, the better the retention will be (in removable partial dentures, the clasps are a major provider of retention), as surface tension, suction and friction will aid in keeping the denture base from breaking intimate contact with the mucosal surface. it is important to note that the most critical element in the retentive design of a maxillary complete denture is a complete and total border seal (complete peripheral seal) in order to achieve 'suction'. the border seal is composed of the edges of the anterior and lateral aspects and the posterior palatal seal. the posterior palatal seal design is accomplished by covering the entire hard palate and extending not beyond the soft palate and ending 1–2 mm from the vibrating line. prosthodontists use a scale called the kapur index to quantify denture stability and retention. implant technology can vastly improve the patient's denture-wearing experience by increasing stability and preventing bone from wearing away. implants can also aid retention. instead of merely placing the implants to serve as blocking mechanism against the denture's pushing on the alveolar bone, small retentive appliances can be attached to the implants that can then snap into a modified denture base to allow for tremendously increased retention. available options include a metal "hader bar" or precision ball attachments. fit, maintenance and relining generally speaking, partial dentures tend to be held in place by the presence of the remaining natural teeth and complete dentures tend to rely on muscular co-ordination and limited suction to stay in place. the maxilla very commonly has more favorable denture-bearing anatomy, as the ridge tends to be well formed and there is a larger area on the palate for suction to retain the denture. conversely, the mandible tends to make lower dentures much less retentive due to the displacing presence of the tongue and the higher rate of resorption, frequently leading to significantly resorbed lower ridges. disto-lingual regions tend to offer retention even in highly resorbed mandibles, and extension of the flange into these regions tends to produce a more retentive lower denture. an implant supported lower denture is another option for improving retention. dentures that fit well during the first few years after creation will not necessarily fit well for the rest of the wearer's lifetime. this is because the bone and mucosa of the mouth are living tissues, which are dynamic over decades. bone remodeling never stops in living bone. edentulous jaw ridges tend to resorb progressively over the years, especially the alveolar ridge of the lower jaw. mucosa reacts to being chronically rubbed by the dentures. poorly fitting dentures hasten both of those processes compared to the rates with well-fitting dentures. poor fitting dentures may also lead to the development of conditions such as epulis fissuratum. in addition, the occlusion (chewing surfaces of the teeth) tends to wear away over time, which reduces chewing efficacy and decreases the vertical dimension of occlusion (the "openness" of the jaws and mouth). costs in countries where denturism is legally performed by denturists, it is typically a denturist association that publishes the fee guide. in countries where it is performed by dentists, it is typically a dental association that publishes the fee guide. some governments also provide additional coverage for the purchase of dentures by seniors. typically, only standard low-cost dentures are covered by insurance and because many individuals would prefer to have a premium cosmetic denture or a premium precision denture they rely on consumer dental patient financing options. a low-cost denture starts at about $300–$500 per denture, or $600–$1,000 for a complete set of upper and lower dentures. these tend to be cold-cured dentures, which are considered temporary because of the lower quality materials and streamlined processing methods used in their manufacture. in many cases, there is no opportunity to try them on for fit before they are finished. they also tend to look artificial and not as natural as higher quality, higher priced dentures. a mid-priced (and better quality) heat-cured denture typically costs $500–$1,500 per denture, or $1,000–$3,000 for a complete set. the teeth look much more natural and are much longer-lasting than cold-cured or temporary dentures. in many cases, they may be tried out before they are finished to ensure that all the teeth occlude (meet) properly and look esthetically pleasing. these usually come with a 90-day to two-year warranty and in some cases a money-back guarantee if the customer is not satisfied. in some cases, the cost of subsequent adjustments to the dentures is included. premium heat-cured dentures can cost $2,000–$4,000 per denture, or $4,000–$8,000 or more for a set. dentures in this price range are usually completely customized and personalized, use high-end materials to simulate the lifelike look of gums and teeth as closely as possible, last a long time and are warrantied against chipping and cracking for 5–10 years or longer. often the price includes several follow-up visits to fine-tune the fit. in the united kingdom, as of 13 march 2018, an nhs patient must pay £244.30 for a denture to be made. this is a flat rate and no additional charges may be made regarding material used or appointments needed. privately, the cost can lie upwards of £300. care daily cleaning of dentures is recommended. plaque and tartar can build up on false teeth, just as they do on natural teeth. cleaning can be done using chemical or mechanical denture cleaners. dentures should not be worn continuously, but rather taken out of the mouth during sleep. this is to give the tissues a chance to recover: wearing dentures at night is likened to sleeping in shoes. the main risk is the development of fungal infections, especially denture-related stomatitis. dentures should also be removed while smoking, as the heat can damage the denture acrylic, and overheated acrylic can burn the soft tissues. deposits such as microbial plaque, calculus and food debris can accumulate on the dentures, which may lead to issues such as angular stomatitis, denture stomatitis, undesirable odors and tastes as well as staining. these deposits can also quicken the degradation of some of the denture materials. due to the presence of these deposits, there is an increased risk of the denture wearer and other people around them developing a systemic disease by organisms such as methicillin-resistant staphylococcus aureus (mrsa), but research shows that denture cleaners are effective against mrsa. therefore, denture cleaning is imperative for the overall health of the denture wearers as well as for the health of people they come into contact with. brushing after receiving dentures, the patient should brush them often with soap, water and a soft nylon toothbrush which has a small head, as this will enable the brush to reach into all the areas of the denture surface. the bristles must be soft in order for them to easily conform to the contours of the dentures for adequate cleaning: stiff bristles will not conform well and are likely to cause abrasion of the denture acrylic resin. if a patient finds it difficult to utilize a toothbrush, e.g. a patient with arthritis, a brush with easy-grip modifications may be used. disclosing solutions can be used at home to make less obvious plaque deposits more visible to ensure thorough cleaning of plaque. food dyes can be utilized as a disclosing solution when used correctly. instead of brushing their dentures with soap and water, patients can use pastes designed for dentures or conventional toothpaste to clean their dentures. however, the american dental association advises against using toothpaste as it can be too harsh for cleaning dentures. immersion patients should combine the brushing of their dentures with soaking them in an immersion cleaner from time to time as this combined cleaning strategy has been shown to control denture plaque. due to microbial invasion, the lack of use of immersion cleaners and inadequate denture plaque control will cause rapid deterioration of the soft linings of the denture. cleansers and methods liquid cleansers that dentures can be immersed in include: bleaches e.g. sodium hypochlorite; effervescent solutions e.g. alkaline peroxides, perborates and persulfates; acid cleaners. sodium hypochlorite cleansers sodium hypochlorite (naocl) cleansers have a disinfectant action and remove non-viable organisms and other deposits from the surface, but they are weak for eliminating calculus from the denture surface. immersing dentures in a hypochlorite solution for more than 6 hours occasionally will eliminate plaque and staining. furthermore, as microbial invasion is prevented, the deterioration of the soft lining material does not occur. corrosion of cobalt chromium has occurred when hypochlorite cleansers have been used, and they may also result in the fading of the acrylic and silicone lining, but the softness or elastically of the linings are not greatly changed. effervescent cleansers effervescent cleansers are the most popular immersion cleansers and include alkaline peroxides, perborates and persulfates. their cleansing action occurs by the formation of small bubbles which displace loosely-attached material from the surface of the denture. they are not very effective as cleansers and have a restricted ability to eliminate microbial plaque. moreover, they are safe for use and do not cause deterioration of the acrylic resin or the metals used in denture construction. despite this, they are able to cause rapid damage to some short-term soft lining. discoloration of the acrylic resin to a white denture often occurs; however, this can be due to the use of very hot water with cleaning agents against manufacturer instructions. acid cleansers sulfamic acid is a type of acid cleanser that is used to prevent the formation of calculus on dentures. sulfamic acid has a very good compatibility with many denture materials, including the