The Different Effects Of Fixed Appliance And Invisalign On Alveolar Bone Remodeling Of Orthodontic Patients With Periodontitis Based On Cone Beam CT Voxel Registration

The flared and elongated anterior teeth effected the masticatory functional and aesthetic occlusion of periodontal patients,and these always became their main complaint actively seeking orthodontic treatment.Nowdays,periodontal-orthodontic treatment had been widely accepted among orthodontitis. orthodontic treatment aligned crowded disorder of teeth, controled dental plaque and relieved occlusal interference, improving patient’s appearance and function, It is worth emphasizing that orthodontic treatment prevented periodontal supporting tissue of further damage. The fixed appliance used maturely in orthodontic-periodontal theory, but if the patient cannot do good oral maintenance, periodontal inflammation will undoubtedly accelerate the further loss of periodontal support tissue. With the development and appliance of thermoplastic material progress, periodontal disease in the field of invisible aligner is no longer a contraindication. More and more adult prefer to invisible aligners.Domestic and foreign scholars have reported lots of successful cases. However, the difference of the effects of the two kinds of appliances on alveolar bone remodeling is rarely reported. This study firstly explored the differences of effects of the fixed appliance and bracketless invisible appliance alveolar bone remodeling in adult periodontitis based on Cone Beam CT voxel normalized mutual information registration method.Objective The purpose of this study was to select adults characterized by labially migrated anterior teeth with periodontitis, treated by Self-ligating Straight Wire appliance and Invisalign respectively.Appling for 3D CBCT based on voxel registration, to quantify and analyse the intrusion of the migrated anterior teeth and the changes of the alveolar bone. Then to investigate the different effects of fixed appliance and Invisalign on alveolar bone remodeling.Exploring the appropriate law for teeth movement. Providing a reference for clinicists and patients to choose the suitable appliance.Materials and Methods Twelve adult patients(22-40 years old,famale) characterized by flared and elongated anterior teeth with periodontitis were selected,who were treated by Self-ligating Straight Wire appliance and Invisalign respectively,in the orthodontics department of Beijing stomatology hospital during 2013-2015. The sample size in each group was 48 teeth. Patients were taken CBCT before and after anterior teeth were intruded and retracted. Analyze 12.0 was used to overlap pre- and post-treatment CBCT based on voxel registration.Then two reference planes were set up: PP plane goes though the anterior nasal spine point(ANS) and the post nasal spine point(PNS), PL plane goes through ANS and perpendicular to the PP plane. The position of apex and midpoint of the incisor edge, the proclination of the teeth, the alveolar bone height, as well as the alveolar bone density were measured.and then the difference between the two groups were measured at the same time. Monitor the periodontal health status during orthodontic treatment.Records of periodontal pocket probing depth(PD), gingival recession(CAL), gingival bleeding(BOP). Pretreatment(T0), leveling and alignment(T1, 10 + 2 months), pressure into the adduction(T2) in three stages of periodontal index into this study.Results1.In the fixed appliance group, The mean intrusion was 0.66±0.24mm(P<0.05). Compared with pretreatment, both the distance of midpoint of the incisal edge and the apex to the PL plane were decreased significantly(P<0.05).The proclination of anterior teeth reduced significantly(P<0.05).The bone height increased 0.37±0.24mm(P<0.05). The density of alveolar bone,especially in the libial and lingual of ridge crest and apex area(P<0.05).2.In the Invisalign group,The mean intrusion was 0.83 ± 0.31mm(P < 0.05). Compared with pretreatment, the distance of midpoint of the incisal edge to the PL plane were decreased, while the apex to the PL plane increased,both were significantly(P<0.05).The proclination of anterior teeth reduced significantly(P<0.05).The bone height increased 0.41±0.15mm(P<0.05). The density of alveolar bone were decreased after treatment, especially the lingual ridge crest area(P<0.05).3. The distance between the midpoint of the incisal edge and the apex to the PP plane decreased in both groups, but no significant difference was found between the two groups.(P > 0.05). The apical plane of PL distance decreased in the fixed group, but increased in the other.(P < 0.05). The reduction of the proclination of anterior teeth were the same in the two groups(P < 0.05).4. Compared to baseline T0, the degree of periodontal pocket depth and gingival recession were improved significantly in the two groups in T1 and T2(P < 0.05). There was no significant difference between the two groups. The bleeding index in fixed appliance group were :T0 19%, T1 12%, T2 6%, while T0 16%,T1 8%, T2 4%. in the other. Both improved after orthodontic treatment.Conclusion Both fixed appliances and Invisalign can be used effectively to retract and intrude the migrated anterior teeth, and significantly promote alveolar bone increase in patients with periodontitis.