The Effects Of Fixed Crown Prosthesis Of Mandibular Molar With Severe Furcation Involvement After Root Separation And Hemisection.

Objective: This research aims to further improve the survival rate of mandibular molar with degree III and IV root furcation involvement, by observing the effect of clinically fixed crown prosthesis of mandibular molar with severe furcation involvement, and providing suitable and effective restoration plan for root with furcation involvement.Methods: 37 patients requiring to treat and restore mandibular molars with degree III and IV root furcation involvement in prosthodontic department of our stomatological hospital were included in the study from Mar. 2013 to Mar. 2015. There are 24 males and 13 females among these patients(age from 24 to 71, average of 42 years old). Totally 38 teeth including 30 first mandibular molars and 8 second mandibular molars were evaluated to comply with the standard of preservation. After the informed consent of the patients and signing consent book, 38 mandibular molars with severe furcation involvement were firstly treated by initial therapy of periodontal diseases, then root separation or hemisection after periodontal tissue recovering well, at lastpost, crown and bridge prosthesis. The valid and invalid methods determine the clinical effect. Standard of judgment is valid: patients have no obvious symptoms, restoration stable, and masticatory function well; no swollen gums, no obvious periodontal pocket, root of loose degrees less than I, no obvious change or smaller low density shadow range in root furcation; no wide periodontal membrane or absorption of surrounding bone in X ray film. Followings are invalid: obvious discomfort of patients’ teeth, unstable restoration, bad masticatory function; swollen gums, deep periodontal pocket, root of loose degree more than II; significantly increased width of root periodontal membrane and absorption of surrounding bone, bigger low density shadow range in root furcation in X-ray film. Finally, it was comprehensively evaluated to the clinical effects of residual teeth and restorations after 2 ~ 24 months’ prosthesis.Results: 38 teeth conducted root canal therapy, root separation or hemisection. After determining no symptoms of these teeth, we conducted post and core, continuous crowns and fixed partial denture. After 2 ~ 24 months’ following up, 34 teeth of total 38 teeth showed well. The success rate of preservation was 89.5 ﹪. These 34 teeth performed normal with good reaction: stable restoration, well masticatory function, the degree of teeth loose better than preoperative loose or no increasing degrees, no swollen gum, no obvious periodontal pocket, no or no bigger low density shadow range in perapical area, root furcation, periodontal membrane and no absorption of surrounding bone in the zone of root furcation in X ray film. The remaining 4 teeth were invalid, performing different clinical symptom. 1 restoration of root separation suffered from mobility, but root furcation area and gums were recovering well. No obviously biggerlow density shadow range in perapical area, periodontal membrane, no absorption of surrounding bone in the zone of root furcation and root furcation performed in X ray film. Then the restoration was bonded again. 2 teeth(one root separation,the other hemisection) showed discomfort, chewing pain and obvious loose, but the restorations were good. Two years of prosthesis later, the teeth of root separation performed swollen gums, repeated pus from gingival fistula in the root furcation area, bigger density shadow range of root furcation spreading to adjacent tooth and two roots, wider periodontal membrane and obvious bigger low density shadow range in perapical area in X ray film. Then it was pulled out. The tooth of hemisection performed obvious bigger low density shadow in perapical area, going with wide periodontal membrane and was pulled out as well. One tooth only appeared swollen gums and no other clinical symptoms. No obvious bigger low density shadow range in perapical area, root furcation, periodontal membrane, and no absorption of surrounding bone in the zone of root furcation performed in X ray film. This tooth just performed subgingival scaling and followed up frequently..Conclusion: Root separation and hemisection can get rid of the furcation involvement thoroughly and persistently, but we need to choose a good indication. Prosthesis of post and core, continuous crowns and fixed partial denture can prolong the time of preservation and improve the masticatory efficiency of root..