A Study On The Food Impaction For Submaxilla Dentition Using The Three-Dimensional Finite-Element Method

Oral health affects not only the appearance and the masticatory function butalso the digestive function. Therefore, it is responsible for the living quality ofhuman being, which has been widely recognized. The World HealthOrganization (WHO) puts forward the dental health standard is8020, i.e. the80-year old should have20functional teeth at least. The aim of establishing thisstandard is to promote the living quality and then to prolong the longevitythrough heightening the service longevity of the teeth.There are many clinical diseases of oral health, e.g. dental disease, dentalpulp disease, periodontal disease, repair and wear of denture, orthodontics,maxilla and oral gland diseases etc. Food impaction, first proposed in1930, is aclinically familiar disease. This disease is defined as the food is squeezed andembedded into the gap between the adjacent teeth. The corresponding patientsoften feel discomfort (symptoms range from swelling to pain) due to theabnormal mechanical action between the adjacent teeth. Bacterial infection willappear if the impacted food is not taken out timely and correctly, which maylead to several dental diseases including bad breath, gum inflammation, swollengums bleeding, gum atrophy, root surface caries, alveolar bone resorption, andeven cause loose teeth. Clinically, there are different viewpoints between theetiology and the mechanism of food impaction. Recently, the correspondinginvestigations focus on the statistics and therapeutics. With the development of the computer technology, the research methods inoral field have not been limited in the traditional research methods, e.g. theclinical research and the physical model. Finite-element method (FEM), amethod combined by the theory of mechanics and the computer technology, hasbeen applied to study the biomechanics in stomatology. The FEM is widely usedto analyze the stress distribution (not only the wear conditions in a singlematerial but also composite materials) of the oral tissues. Especially, the FEMcan simulate the actual situation of displacement and the loading force in anyrandom oral modeling part; and then the available mechanical parameters areobtained.Food impaction is the domestically common complaint of oral patients.However, using FEM to study the causes, the differences between the abnormaland normal teeth, the treatment indiction and other intrinsic factors is rarely little.So by using FEM, we can further explore the impact of the mechanicalenvironment in the oral, and provide grounds for the study of the causes,treatment and prevention of food impaction. This work mainly use Mimics toprocess the spiral CT images of the mandible, then obtain a3D model ofmandibular dentition. And by LS-DYNA simulation analysis, we study theresponse of the different position and dental tissue of the food impaction.The result shows, that for the same position between teeth, the smaller the clearance distance is, the more difficultly food fiber plug into the embedded. Dueto the larger surface area, the molar suffer more binding from the root than the incisors, and stuffed food difficultly.Due to the binding direction from more roots,periodontal good teeth are unlikely to cause impaction. Tooth gap and binding have a greater impact on food impaction, this provides starting point for the clinical treatment of food impaction. To treat and ameliorate food impaction, we can close and reduce the gap and improve periodontium.