Three-dimensional Finite Element Analysis Of Fixed, Removable Partial Denture And Telescopic Crown As Periodontal Splints

Prosthetic therapy for periodontitis is one of the most complicated treatments for the periodontally compromised patients. Clinically , permanent periodontal splints including fixed ,removable partial dentures and telescopic crowns are usually used to stabilized those mobile teeth after the fundmental periodontal therapy in order to reduce the mobility of the residual teeth , distribute the occlusal forces and improve the masticatory function and comfort of the patients by restoring the missing teeth. But in a very long time , the knowledge about the function of periodontal splints is maily acquired by clinical observation and lack of scientific research. As to evaluate the real effectiveness of the several periodontal splints and compare them with each other , three biomechanic experiments are performed to accomplish the above objectivenss by means of finite element analysis so as to provide the evidents for the clinical researches.Objective: To establish the three-dimensional finite element models of three permanent periodontal splints including fixed , removable partial dentures and telescopic crowns, the strain difference in the periodontal membrane of the residual teeth under different situations is evaluated in order to provide the scientific evidence for the proper selection of periodontal splints and improve the strain distribution of the periodontal membrane. Methods:1. First portion the adjustment and analysis of the the finite element model of the mandible with full dentitionTo adjust the geometric models of the mandible with full dentition( including the dentition,alveolar bone and periodontal memebrane) and create the three dimensional finite element models so as to analyse the effectiveness of the above models and provide a platform for the three dimensional finite element research of the fixed,removable and telescopic crown periodontal splints for the full and defected dentition in the future .2. Second portion the three-dimensional finite element analysis of fixed ,removable and telescopic splints of the mandible with full dentitionAdjust the alveolar bone of the mandible and construct three dimensional geometric and finite element models of the fixed ,removable and telescopic crown periodontal splint with different height of alveolar bone ,analyse the difference of the stress distribution in the periodontal membrane among the three periodontal splints so as to provide the evidence to select the proper periodontal splints under different periodontal situations.3. Third portion . the three-dimensional finite element analysis of fixed , removable and telescopic splints of the partial edentulous mandible.To creat the geometric models of the defected dentition of the mandible with different height of alveolar bone and construct the models of fixed ,removable and telescopic crown periodontal splints in order to analyse the stress distribution and difference among the three periodontal splints with the decreasing absorption of the alveolar bone so as to provide the reference evidence of the selection of the periodontal splints for the periondtally compromised patients with defected dentition. Results:First portion1. In the anterior region, the stress of the cuspid is minimum because of its maximum periondontal membrane among the anterior teeth2. In the bicuspid region , the stress of the second premolar is higher than that of the first premolar since the periodontal membrane area of the former is bigger than the latter as well as its higher degree of inclination .3. the maximum stress is mainly focused in the the furcation area , the apical area and the cervical region of the lingual surface of the mesial root , which is in accordance with the previous research results.4. In the molar aera, the value of maximum principal stress of the second molar is higher than the first molar with more periodontal membrane aera. in intercuspal positionSecond portion1. The stress analysis of the difference among the fixed , removable and telecopic crown splint under the same situation of alveolar bone resorption.1) The stress of the periodontal membrane is reduced after the restoration of the three periodontal splints2) The stabilization of the fixed and telecopic crown splint is better than the removable splint .3) Different design of the removable splint can bring the according variation among the periodontal membrane . if the removable splint is restored with desigh one , the stress in the cuspid area is so high that the health will be compromised by the sceodary trama occlusionThe minor connector is very effective in reducing the stress of the residual teeth if it is used in the area between the second premolar and the first molar.2. The stress analysis of the difference among the different alveolar bone resorption with the same periodontal splint.Third portion1. The stress analysis of the difference anong the situation before and after the restoration of the fixed , removable and telecopic crown periodontal splint .2. The stress analysis of the difference anong the fixed , removable and telecopic crown splint under the same situation of alveolar bone resorption.3. The stress analysis of the difference among the different alveolar bone resorption with the same periodontal splint.Conclusion:We have established a much more systemic and comprehensive three-dimensional finite element model of the human masticatory system, which could be used as a platform to study the biomechanical behavior of human masticatory system.1. All of the three different periodontal splint can reduce the stress of the periontal membrane of the residual teeth with the full dentition . The stabilization of the fixed and telecopic crown splint is better than the removable splint .2. When the dentition is partially edentulous ,the fixed and telecopic crown periodontal splint can also reduce the stress of the periodontium .but as to the removable splint ,the stress of the periodontal membrane is becoming higher with worse ability of stabilization.3. Different design of the removable splint can bring the according variation of stress among the periodontal membrane ,which can effectively transmit the stress to other area .4. If the dentition is become edentulous , the stress of the cuspid is highly increased than before ,which tells us that we should pay more attention to the periontal health of the cuspid.Once it is periodontally compromised , we should avoid using the removable splint as possible as we can.