[Comparative study on the accuracy of implant-borne single restoration by two production processes with Ti-base].

PURPOSE: To study on the accuracy of implant-borne single restoration by two production processes with Ti-base to provide experimental data for proper processes of single implant-borne restoration. METHODS: Thirty patients were selected with single posterior teeth missing from the Department of Oral Implantology of Shanghai Putuo District Eye Disease and Dental Disease Prevention and Treatment Institute. The patients were taken 2 traditional impressions clinically for two plaster model equipped with implant analogue. These models were then divided into 2 groups according to different production processes. The experimental group was scanned with the scan body installed in the model implant analogue, while the control group was scanned directly on the Ti-base abutment installed in the model implant analogue. The implant-borne single restorations of the two groups were cut along the buccal-lingual side and the distance between the measuring point to the Ti-Base abutment was observed by electron microscopy. In addition, the breaking limit of zirconia crown was observed, universal test machine was used to load direct force to the crown. SPSS 22.0 software package was used for data analysis. RESULTS: The gap between the implant-borne single restoration to the Ti-base abutment of the experimental group was significantly smaller than that of the control group. The difference between the two groups was statistically significant (P<0.05). However, by testing the breaking limit of zirconia crown, there was no significant difference(P>0.05). CONCLUSIONS: Using scan body to transfer the implant position and Ti-base abutment data information to the digital dental design software is more accurate and reliable than directly scanning the Ti-base on the model analogue. Using scan body is recommended for processing and manufacture of implant-borne singe restoration.

[Clinical effectiveness evaluation of gingival recession by using perioscope as an adjunct to non-surgical periodontal therapy].

PURPOSE: To investigate the effects of ultrasonic scaling and root planning(SRP) assisted by perioscope on gingival recession of maxillary lateral incisor. METHODS: Thirty-six outpatients with moderate to advanced chronic periodontitis from the Department of Periodontology at Dental and Ophthalmic Clinic of Putuo District from June 2020 to December 2020 were collected as research objects. Periodontal treatment was carried out according to a single-blind split-mouth self-control design randomly with(experimental group, namely perioscope group) or without(control group, namely SRP group) periodontal endoscope．The labial periodontal probing depth (PD), labial attachment loss (AL) and gingival recession(GR) in the maxillary lateral incisors were recorded at baseline, 3 and 6 months, and compared among groups by SPSS 22.0 software package. RESULTS: There was no significant difference between perioscope group and SRP group at baseline. ΔGR (the recession extent of gum within two observation time) in perioscope group was significantly smaller than that in SRP group at 3 months（P<0.05）. There was no significant difference in other periodontal indicators at 3 and 6 months between the 2 groups after treatment, but it can be found that the degree of PD reduction and AL improvement in perioscope group was more than those in SRP group, this trend was most obvious at 3 months. PD and AL were significantly different between baseline and 3 months or 6 months in the two groups. There were significant differences in ΔGR at 3 months and 6 months between the two groups. CONCLUSIONS: Compared with routine SRP, the extent of root surface debridement with perioscope-assisted SRP is thorough and less invasive, and the reduction of gingival recession of labial surface of maxillary lateral incisor at 3 months is significantly less; thus, the aesthetic effect is prominent.

[The effect and safety of two techniques of immediate implants on alveolar bone length, soft and hard tissue in the anterior maxillary zone].

PURPOSE: To investigate the effect and safety of two techniques of immediate implants on the length of alveolar bone as well as the soft and hard tissue in the anterior maxillary zone. METHODS: One hundred and sixty cases of immediate implants in anterior maxillary zone were collected from August 2014 to August 2015 in our hospital. They were randomly and equally divided into flap group (80 cases) and flapless group (80 cases). The former received flap immediate implant while the later received flapless therapy. A 1-year follow-up, comparison on alveolar bone length, soft tissue and complications was carried out and the results were recorded. The data were analyzed with SPSS 17.0 software package. RESULTS: The number of surviving implants with flap was 63 and the survival rate was 97.5%, while the number of the surviving implants in the flapless group was 63 with survival rate being 78.75% (P<0.05). Patients in both groups had pain, bleeding, edema and other complications. The incidence rate of complications of flapless group was 11.25%, 6.25%, 8.75% respectively and the total rate was 26.25% while that of the flap group was 23.75%, 16.25%, 20%, respectively, and the total rate was 60% (P<0.05) .The depth of gingival sulcus between the two groups had no significant difference after treatment (P>0.05). The alveolar bone crest absorption and length decreased after implantation, meanwhile, there was also significant difference between the two groups after implantation (P<0.05). CONCLUSIONS: Immediate dental implantation without flap can reduce the length of the alveolar bone and operative complications and improve the contour and physiological condition of soft and hard tissue more than that with flap.