Abstract:

BACKGROUND: Mandibular first molar is clinically more common oral diseases. Clinically, the first molar for a variety of repair methods, compared to the traditional fixed bridge, implant because of their chewing efficiency, less damage to the adjacent teeth and gradually began to widely adopt. Ability to support the implant is designed to be taken into account, together with the supporting tissue implant into a mechanical exercise load to bear chewing function structure, this structure is not destroyed to achieve long-term stability to function, must be consistent with biomechanical principles.
OBJECTIVE: Dentition lack is one of common oral diseases, it has become an important oral developed direction by planting repair to restore missing teeth by common methods of cultivation including a single implant repair and crown a single fixed bridge repair and so on. Different cap ratios of restoration implants have become an important factor influencing the long-term effects for restoration implants. Therefore, through CT scan this issue made two solid models by computer, which embrace normal human mandible and mandibular dentition three-dimensionally. And on the basis of solid models, it generated finite element models by large-scale finite element analysis software. We compared the stress distribution of implants of different crown-to-root ratios. Thus, it laid the theoretical foundation for the lack of clinical dental restoration.
METHODS: This issue acquired general outline of the mandible and mandibular dentition by CT technology. It fitted overall image according to graphics features by picture control system, and then generated cloud chart by computer software. We proceed three-dimensional reconstruction according to the cloud chart, as a result, we gained three-dimensional finite element models of mandible and mandibular dentition. Moreover, we established three-dimensional models of two-highest single-root implants to repair the mandibular first molar. To apply Hyperwprk8.0 and Ansys11.0, we established mandibular implant prosthesis models of different crown-to-root ratio implants, and finished the crown restoration. On the basis of the simulated same direction load, we compared the stress distribution of implants with different crown-to-root ratios.
RESULTS AND CONCLUSION: We gained three-dimensional finite element models of mandible and mandibular dentition and mandibular prosthesis models of different crown-to-root ratios. When parallel to the direction of the implant was forced, the implant apical and around bone tissue were concentration zone of stress. The influences of different crown-to-root ratios are faint for jaw force in the direction of implant embedded, but great in the buccolingual direction. Therefore, the stability of the dental implant is considered in the horizontal direction. If space conditions are not permitted, the posterior area could be considered after a dental implant support.