The human maxillary dental arch is located in the upper part of the mouth, so it can't move at will, and the roof of the palate is high and large, so the denture base has a large area and strong adsorption, which is beneficial to the retention of the denture. The mandibular arch is horseshoe-shaped (because the tongue occupies a large area of the oral cavity), and its area is obviously smaller than that of the upper jaw. Moreover, the tongue movement during speaking and chewing is also the main factor that is not conducive to the retention of the lower denture. In addition, the absorption of alveolar bone is along the root direction, and long-term edentulous implants are likely to lead to the inclination of mandibular alveolar ridge (inclined to the lingual side without retention) or low and narrow after absorption. The surrounding tissues such as lip, cheek, tongue and soft tissue at the root of tongue are loose and fluid, and the contraction strength and direction of each muscle are different. Because patients who wear complete dentures for the first time can't coordinate these tissues well, lower dentures are more likely to dislocate than upper dentures. If the accuracy and adsorption force are not ideal when taking impression, the denture edge is too long or too short, and the denture tissue surface is not in close contact with mucosa, which will affect the edge sealing effect, lead to the failure of air pressure and adsorption force, and also affect the retention of lower denture.
For more questions about complete denture, please consult Guizhou Hande Stomatological Hospital. After years of development, Guizhou Hande Stomatological Hospital has now formed a direct chain map based on the Central China market, with Wuhan as its headquarters and distributed in Wuhan, Chongqing, Nanjing, Gansu, Changsha and other cities. With the chain operation mode of "3+ 10", it has continuously expanded to the national strategic layout covering 19 cities, forming a group operation mode with economies of scale and collective operation.