[Treatment of combined periodontal-pulpal lesions with periodontal therapy].

PURPOSE: To evaluate the clinical effects of periodontal therapy for combined periodontal-pulpal lesions. METHODS: One hundred and nine patients with periodontal-pulpal lesions were included in this study, with total 120 teeth. All the teeth were treated by perfect root canal therapy, and than divided into group A and B. Group A was treated with periodontal therapy (60 teeth). After 2 weeks of root canal therapy, basic periodontal therapy was performed. After 6 weeks, patients with more than 5 mm periodontal pockets and bleeding after probe were treated with valvuloplasty. Group B underwent non-periodontal treatment (60 teeth), root canal therapy and supragingival scaling alone. The patients were followed up for 3, 6, 12 and 24 months after operation. SPSS 22.0 software package was used to analyze the indexes at initial diagnosis and 24 months after operation. RESULTS: In group A, the depth of periodontal pockets was significantly reduced before and after PD, from(5.966±1.877) mm to(5.133±1.935) mm. The periodontal pocket depth of group B was significantly increased before and after operation, from(5.533±1.856) mm to (6.167±1.927) mm. The degree of tooth mobility (TM) before operation was similar between the two groups (P>0.05). Two years after operation, the degree of TM in group A was significantly lower than that in group B (P<0.05). There was no significant change in alveolar bone resorption before and after operation in group A (P>0.05). The alveolar bone resorption in group B changed significantly before and after operation (P<0.05). CONCLUSIONS: Root canal therapy combined with periodontal therapy for combined periodontal-pulpal lesions can achieve good results. It can be widely used in clinic.

[Study on the practice and effect of target teaching method in teaching of dental technology interns].

PURPOSE: To standardize the teaching process of interns in dental technology so as to make the learning progress and process goals more clearly and improve the teaching quality. METHODS: Thirty-two junior interns were selected from medical colleges and universities from 2014 to 2017, based on same learning ability, learning attitude, learning achievement and hands-on ability ，they were randomly divided into 2 groups. The experimental group adopted the goal teaching method, using relevant teaching materials, applying theory to practice closely, and trying to standardize practice. The control group entered the production lines directly without teaching materials, the students were all owed only to see, think and manipulate. The data were analyzed with SPSS 18.0 software package. RESULTS: The exam scores of the students in the experimental group were significantly higher than that of the students in the control group. Moreover, the satisfaction with the teaching methods of the experimental group was significantly higher than that of the control group (P<0.05). CONCLUSIONS: The target teaching method is effective in teaching dental technology. Students clearly understand the study progress, process goals and their operational performance is significantly improved.

[Clinical study of premolar extrusion with subgingival decayed defect by one-couple orthodontic NiTi auxiliary arch].

PURPOSE: To evaluate the effect of one-couple orthodontic NiTi auxiliary arch on the premolar extrusion which had subgingival decayed defect. METHODS: A total of 30 cases with subgingival decayed defects over 2 mm under the proximal gingival margin were chosen including 18 first premolars and 12 second premolars. The first and second molars on the same side were connected steadily and the one-couple orthodontic force system was designed. The NiTi segmental arch was used to extrude the teeth. Student's t test was performed with SPSS 8.0 software package. RESULTS: All the defect margins were 1mm over the gingival margins and the extrusion distance was 2.6~4.1 mm. After extrusion, the crown-root ratio was 1.24±0.30, the depth of the gingival sulcus was 1.87±0.28 mm. There was no significant difference before and after treatment in the angle between the axis of the extruded teeth and that of the first molar (P>0.05). The anchorage teeth kept almost the same relationship with the opposite. CONCLUSION: One-couple orthodontic NiTi auxiliary arch could extrude the premolars with subgingival decayed defects effectively and precisely. The designed force system had little effect on the anchorage teeth.

[Evaluation of the effect of one-step self etching adhesives applied in pit and fissure sealing].

PURPOSE: To observe the effect of three one-step self etching adhesive systems used in fit and fissure sealant and explore the feasibility of application in caries prevention in school. METHODS: Seven hundred and twenty completely erupted mandibular first molars in 360 children aged 7 to 9 years old were chosen. The split-mouth design was used to select one side as the experimental group, divided into A1(Easy One Adper), B1(Adper Easy One), and C1(iBond SE).The contra lateral teeth served as A2,B2 and C2 groups (phosphoric acid). The retention and caries status were regularly reviewed .The clinical effect of the two groups was compared using SPSS19.0 software package for Chi - square test. RESULTS: At 3 and 6 months, pit and fissure sealant retention rate in A1 and A2, B1 and B2,C1 and C2 group had no significant difference. At 12 months, sealant retention in A1 and B1 group was significantly lower than A2 and B2 group (P<0.05). No significant difference was found between C1 and C2 groups (P>0.05). At 24 months, sealant retention rate in A1, B1 and C1 group was significantly lower than A2, B2 and C2 group (P<0.05). The caries rate in A1and A2, B1 and B2, C1 and C2 group had no significant difference during different follow-up time (P>0.05). CONCLUSIONS: The clinical anticariogenic effect of three kinds of one-step etching adhesives and phosphoric acid etching sealant was similar .One-step self etching adhesive system was recommended for pit and fissure sealant to improve the students' oral health. The long-term retention rate of one-step self etching adhesive system was lower than the phosphoric acid method to long term observation is needed.

[Casting Nance arch which allowed the upper canine's self-adjustment in the extraction cases].

PURPOSE: To study the upper canine's self-adjustment after the first premolar extraction and the effect of casting Nance arch in the sustainment of the upper first molar position. METHODS: Twenty severely crowded adolescents whose upper canines were in labial malposition were chosen. After the treatment plan was made, the upper first premolars were removed, the individually made casting Nance arches were fixed on the upper first molars. The measurement and fixed orthodontic treatment began 6 months later. Graphpad Prism 6.0 software was used for data analysis. RESULTS: The average movement of the malpositioned canines was （3.6±0.1）mm (P<0.01); while the forward movement of the first molars was （0.2±0.16）mm (P>0.05). CONCLUSIONS: Extraction of the first premolars is beneficial to the canine's self-adjustment in adolescents and the casting Nance arch could help keeping the first molar's positions.

[Analysis of the possible causes of endodontic treatment failure by inspection during apical microsurgery treatment].

PURPOSE: To analyze the possible causes of previous endodontic treatment failure by microscopic inspection during apical microsurgery. METHODS: Two hundred and eighty-nine teeth of previous endodontic treatment failure were collected from patients in Shanghai Xuhui District Dental Center, between January 2006 and January 2014. All surgical procedures were performed by using an operating microscope, and 238 roots were included in the study. The surface of the apical root to be resected or the resected root surface after methylene blue staining was examined during the surgical procedure and inspected with 26 magnification to determine the state of the previous endodontic treatment by using an operating microscope. Fisher's exact test was used to analyze the data with SPSS 19.0 software package. RESULTS: Among the 238 roots with periapical surgery, analysis of the reasons for previous endodontic treatment failure included leaky canal (29.41%), missing canal (15.55%), underfilling (15.55%), anatomical complexity (7.98%), overfilling (4.20%), apical fenestration (4.20%), iatrogenic problem (3.36%), apical calculus (2.52%), apical cracks (1.68%) and unknown reasons (15.55%). The frequency of possible failure causes and tooth position were closely correlated (P<0.001). CONCLUSIONS: Apical microsurgery can better inspect possible causes of previous endodontic treatment failure, in order to improve the success rate of endodontic treatment.

[Application of miniscrew for extraction of mesially impacted wisdom tooth adjacent to the inferior alveolar nerve canal].

PURPOSE: To study the value of miniscrew for extraction of mesially impacted wisdom tooth adjacent to the inferior alveolar nerve canal. METHODS: Fourteen mesially impacted wisdom teeth were proven to be adjacent to the inferior alveolar nerve canal by means of cone-beam CT scan. The treatment began with the miniscrew traction of the wisdom teeth. After 2-5 months, they were moved away from the canal and then extracted. RESULTS: After extraction, all 14 cases did not show any obvious side effect. CONCLUSIONS: Application of miniscrew traction is a valuable method for minimally invasive extraction of mesially impacted wisdom tooth that is adjacent to the inferior alveolar nerve canal.

[Effect of different bonding procedure and root region on bond strength of fiber posts to root canal].

PURPOSE: To evaluate the effect of different bonding procedure and different root region on the bond strength of fiber posts to root canal. METHODS: Forty-two extracted intact human maxillary central incisors were endodontically treated with post spaces be prepared and divided into 6 groups randomly. The fiber posts were then luted with the following different bonding procedures. Group I: total etch dentin bonding agent Luxabond + self-adhesive system Rely XTM Unicem; Group II: total etch dentin bonding agent Luxabond + dual-cure rein cement Luxacore; Group III: self etch dentin bonding agent Contax + self -adhesive system Rely X TM Unicem; Group IV :self etch dentin bonding agent Contax + dual -cure rein cement Luxacore; Group V:self-adhesive system Rely X TM Unicem; Group VI:dual-cure rein cement Luxacore. After dowel cementation, thin-slice push-out test was performed. The bonding interface and dentin surface were examined under scanning electron microscope. The data was statistically analyzed using SPSS13.0 software package. RESULTS: The results showed that different bonding procedures had significant different impacts on the bond strength (P<0.05).Group I and Group III had significantly higher bond strength compared with other groups. Resin tags of dentin bonding interface were observed in Group I and Group II and intimate adaptations of resin cement with the substrate were revealed. CONCLUSIONS: Coupled with total etch or self etch dentin bonding agent, self- adhesive system Rely X TM Unicem can improve the bonding strength of fiber posts obviously.

[Dynamic analysis of the rigid fixed bridge and related tissue after intrusion of abutment with micro screw implant].

PURPOSE: To study the variety of mechanical behavior of fixed bridge after abutments being intruded by micro screw implant and to provide theoretical principles for clinical practice of teeth preparation after intrusion of abutments under dynamic loads. METHODS: Two-dimensional images of maxilla, teeth and supporting tissues of healthy people were scanned by spiral CT and were synthesized by Mimics10.01, Ansys13.0, etc. The three-dimensional finite element mathematical model of rigid fixed bridge repairing on double end of maxillary molar was developed. Under the condition of 10% simulative abutment alveolar absorption, vertical and oblique dynamic forces were applied in a circle of mastication(0.875 s) to build mathematical model after the abutment had been intruded for 0.5, 1.0, 1.5 and 2.0 mm. Stress variety of prosthesis, teeth, periodontal ligaments and supporting tissues were compared before and after intrusion of abutments. RESULTS: Stress variety of the prosthesis occurred, which had close relationship with the structure of prosthesis and teeth, the areas of periodontal ligaments increased, stress on the whole decreased along with the increase of the length of intrusion. With time accumulating, the stress value in prosthesis, teeth, periodontal ligaments and supporting tissues increased gradually and loads in oblique direction induced peak value stress in a masticatory cycle. Some residual stress left after unloading. CONCLUSIONS: By preparing the fixed bridge after abutment intrusion by micro screw implant, the service life of abutment and fixed bridge prosthesis can be reduced. The abutment and its related tissue have time-dependent mechanical behaviors during one mastication. The influence of oblique force on stress was greater than vertical force. There is some residual stress left after one mastication period. With the increase of the intrusion on abutment, residual stress reduced.

Downregulated LncRNA-ANCR promotes osteoblast differentiation by targeting EZH2 and regulating Runx2 expression.

Long noncoding RNAs (lncRNAs) are key regulators of diverse biological processes such as transcriptional regulation, cell growth and differentiation. Previous studies have demonstrated that the lncRNA-ANCR (anti-differentiation ncRNA) is required to maintain the undifferentiated cell state within the epidermis. However, little is known about whether ANCR regulates osteoblast differentiation. In this study, we found that the ANCR expression level is significantly decreased during hFOB1.19 cell differentiation. ANCR-siRNA blocks the expression of endogenous ANCR, resulting in osteoblast differentiation, whereas ANCR overexpression is sufficient to inhibit osteoblast differentiation. We further demonstrated that ANCR is associated with enhancer of zeste homolog 2 (EZH2) and that this association results in the inhibition of both Runx2 expression and subsequent osteoblast differentiation. These data suggest that ANCR is an essential mediator of osteoblast differentiation, thus offering a new target for the development of therapeutic agents to treat bone diseases.

[Investigation of the first permanent molar caries in primary school students in Xuhui District of Shanghai Municipality].

PURPOSE: To investigate the prevalence and current status of caries about the first permanent molars of students in elementary schools in Xuhui District of Shanghai Municipality in order to provide evidence for prevention and treatment strategies of caries. METHODS: Random cluster samples of 5698 students aged from 7 to 12 years old were examined with regard to caries epidemic status of the first permanent molars. The results were analyzed by SPASS13.0 software package. RESULTS: The caries prevalent rate of the first permanent molars was 16.18%.The mean DMFT of the caries patients was 1.80. The females' mean caries prevalent rate and DMFT of the first permanent molars were both significantly higher than males'. The caries rate increased rapidly with aging from 7 to 12(P<0.01).The overall filling rate of the first permanent molars was 56.04%.The prevalence of the first permanent molars in the mandible was significantly higher than that in the maxilla (P<0.01).The caries rate of students, who brushed teeth twice a day or more, was significantly lower than those who brushed teeth once a day or less. CONCLUSIONS: The caries prevalence of the first permanent molars in students of 7 to 12 years old in elementary schools in Xuhui District of Shanghai municipality was less optimistic. Some concrete measures should be taken to prevent and treat caries.

[Clinical observation of screw and cement-retained implant-supported restoration of fixed bridges].

PURPOSE: To compare the prosthetic outcome of screw- and cement-retained implant-supported restorations of the fixed bridges. METHODS: A total of 185 Straumann implants were placed in the alveolar bone of 68 partially edentulous patients from Jan. 2006 to Dec. 2007. All of them were 2 to 6 units of combination crowns with Straumann system. Then they were followed up for 3 years. In each group, the retention, influence on hard and soft tissues, passive fitting and rupture strength of the ceramic layer were evaluated. The data was analyzed with SPSS12.0 software package. RESULTS: There were more advantages of retention and the rupture strength of the ceramic layer in the cement-retained group, while there was less influence on the hard and soft tissues, and more facility of maintenance and reparation in the screwed-retained group. The difference between the two groups was statistically not significant (P>0.05). CONCLUSIONS: The clinical outcomes of implant restorations are satisfactory, either screw-retained or cement-retained. Cement retention is used in 2 to 3 unit combination crowns, while screw retention is more suitable for complicated cases.

[A short term clinical evaluation of IPS e.max Press all-ceramic crowns].

PURPOSE: The aim of this study was to evaluate the clinical effect of IPS e.max Press crowns. METHODS: A total of 127 IPS e.max Press crowns was placed in forty-one patients from 2007 to 2009. The crowns were evaluated with a modified USPHS criteria for color match, marginal discoloration, fracture, secondary caries, marginal adaptation and gingival health for a period of 12 to 42 months, with a mean of 28 months after insertion. A,B,C and D ratings were assigned. RESULTS: 94.49% of the crowns were rated as A and 5.51% rated as B for color match and marginal adaptation. 1.57% of the crowns was detected with marginal discoloration and one crown(0.79%) was detected with veneer chipping. No secondary caries was detected, and 93.70% of the crowns were rated as A, 4.72% rated as B and 1.58% rated as C for gingival health. CONCLUSION: IPS e.max Press crowns exhibit excellent clinical performance over a mean evaluation period of 28 months.

[Osteotome sinus floor elevation without bone grafting: a 2-year prospective clinical study].

PURPOSE: The aim of this study was to evaluate the osteotome sinus floor elevation procedure with Straumann implants without bone grafting through observing the implant survival rate and the change of bone around the implant, and explored new bone formation and stability when the implants protruding in the sinus less than 3mm. METHODS: 23 patients with single upper maxillary molar lost were included in this study. The mean residual bone height (RBH) under the maxillary sinus was 5-8 mm and the distance of the implants protruding into the sinus was less than 3mm without bone grafting. A healing period of 3-4 months was allowed before abutment tightening at 35 N x cm. All the patients were followed up for 2 years to evaluate the implant survival rate. X-ray measurements (immediately after implant placement, after 3,6,12,24 months postoperatively) were performed to calculate the length of the implant protruding into the sinus and if the new bone formed near it. RESULTS: At the end of 2-year, the implant survival rate was 100% and the implants resisted the applied 35 N.cm torque and supported the definitive prosthesis well. The mesial and the distal sides of the implants protruding into the sinus had new bone formation. No hard tissue could be seen around the apical implant 3 months after inserting and the boundary between the new bone and the original sinus floor could not be seen 2 years after surgery. CONCLUSION: Elevation of the sinus membrane alone without addition of bone grafting could have the similar effect to the OSFE with bone grafting.