上海口腔医学最新文献

Purpose: To evaluate the clinical effect of a new fixed Twin-block on adolescent patients with skeletal ClassⅡ malocclusion.

Methods: Twenty-one patients aged 10-13 years with skeletal ClassⅡ malocclusion with mandibular retrusion were chosen for functional treatment using a new fixed Twin-block. Before and after treatment, panoramic and cephalometric films were taken, and the observation indexes were measured and recorded.

Results: There was no loosening or destruction of the appliance during treatment, the mean duration of treatment was (11.42±1.78) months. The position of the mandible(SNB), the length of the mandible (Co-Gn), nasolabial angle (Cm-Sn-UL), condylar sagittal position(Pcd-S), the lower labial protrusion distances (LL-SnPg') were significantly increased (P＜0.05) after treatment, and the relative position of the maxilla and mandible (ANB), Y-axis angle(SGn/FH), the inclination of the maxillary incisors (U1/SN), and the depth of the mental-labial sulcus (Si-LLPg') reduced(P＜0.05). Maxillary position(SNA), posterior mandibular position(S Vert-Co), mandibular length(Go'-Me), the mandibular incisor inclination (IMPA), and upper and lower mesial incisor angles(U1/L1), protrusion of the upper lip (UL-SnPg') were changed but without significant difference(P＞0.05). The vertically orientated measurements of the vertical position of the lower dentition(Ll-MP), L6-MP, the vertical distance of the upper and posterior teeth (U6-PP), anterior height (N-Me), facial height index(S-Go'/N-Me), and mandibular plane angle (MP/SN) did not change significantly(P＞0.05), while the posterior height(S-Go'), the vertical position of the upper dentition(U1-PP), occlusal plane angle (SN/OP), mandible height (Ar-Go'), the mandible ramus height(Co-Go) was increased significantly (P＜0.05).

Conclusions: New fixed Twin-block significantly promotes mandibular growth and provides effective vertical control, improves the facial profile by retracting the maxillary incisors, and the clinical effect is reliable.

Purpose: To evaluate the effects of Er:YAG laser combined with NaClO on the removal of root canal taint layer, calcium hydroxide clearance and dentin microhardness.

Methods: A total of 318 single-rooted extracted teeth collected from March 2021 to January 2024 were selected, the 13 mm root was taken and mechanically prepared and randomly divided into three groups, with 106 teeth in each group. The control group was rinsed with NaClO, the experimental group 1 was rinsed with NaClO combined with ultrasonic washing, and the experimental group 2 was treated with Er:YAG laser on the basis of NaClO. The removal of the smear layer was observed under electron microscope, and the microhardness of dentin post-treatment was assessed using a microhardness tester.

Results: The clearance rate of calcium hydroxide in experimental group 2 was significantly higher than that in experimental group 1 and control group, and the stain layer scores of crown formula 1/3, root middle 1/3 and root tip 1/3 were significantly lower than those in the other 2 groups(P＜0.05). There was no significant difference between the initial and final microhardness of the three groups(P＞0.05).

Conclusions: Er: YAG laser combined with NaClO can effectively enhance the removal effect of stain layer in root canal therapy, and has little effect on dentin microhardness.

Purpose: To evaluate the equivalent stress and displacement of maxillary sinus floor mucosa by three-dimensional finite element analysis under different types of maxillary sinus floor.

Methods: Three-dimensional finite element models of three different maxillary sinus floor shapes (shallow concave, deep concave and convex) were established by three-dimensional reconstruction of maxillary sinus bones and mucosa. The process of applying dynamic impact load to the maxillary sinus floor was simulated by using the ejector during maxillary sinus lifting operation, and the biomechanical characteristics of different maxillary sinus floor mucosa during ejection was analyzed.

Results: The equivalent stress and displacement of maxillary sinus floor mucosa were deep concave (0.518 90 MPa/0.002 955 mm), shallow concave (0.590 25 MPa/0.003 515 mm) and convex (0.623 56 MPa/0.003 660 mm). In the process of axial displacement of the ejector from 1-10 mm, the stress of the mucosa at the bottom of maxillary sinus increased uniformly.

Conclusions: The equivalent stress level of mucosa is related to the morphology of sinus floor. Under the same load condition, the tension on mucosa increases obviously during internal lifting of convex maxillary sinus floor, which has an adverse effect during internal lifting operation.

Purpose: To investigate the clinical effect of piezosurgery combined with 45°contra-angle turbine drill in extraction of impacted mandibular wisdom teeth.

Methods: A total of 146 patients with impacted wisdom teeth at the median mandibular level admitted from June 2022 to June 2024 were randomly divided into control group and experimental group, with 73 cases in each group. The wisdom teeth in the control group were simply removed using 45° contra-angle turbine drill, while those in the experimental group were removed using piezosurgery combined with 45° contra-angle turbine drill. The treatment outcomes, postoperative pain, limited swelling and incidence of postoperative complications of the two groups were compared.

Results: There was no significant difference in operation time between the two groups(P＞0.05), and the amount of blood loss in the experimental group was significantly lower than that in the control group(P＜0.05). The visual analogue scale(VAS) of pain in the experimental group was significantly lower than that of the control group on the 1st and 3rd day after surgery(P＜0.05). Immediately, 1 day and 3 days after surgery, the serum C-reactive protein (CRP) in the experimental group was significantly lower than that in the control group (P＜0.05). The score of facial swelling degree and proportion in the experimental group were significantly lower than those in the control group (P＜0.05), the reduction rate of mouth opening degree and the proportion of mouth opening restriction in the experimental group were significantly lower than those in the control group(P＜0.05). There were no significant differences in the total incidence of postoperative complications such as tongue numbness, lower lip numbness, adjacent tooth injury, dry socket and root fracture between the two groups(P＞0.05).

Conclusions: Compared with only using 45° contra-angle turbine drill, the combination of piezosurgery for impacted mandibular wisdom teeth extraction can help reduce intraoperative bleeding, alleviate pain and swelling,improve the degree of limited mouth opening.

Purpose: To investigate the effect of minocycline hydrochloride(MH) loaded nano-silica microspheres(MSNion) on the inflammatory regulation of periodontitis in rats.

Methods: Mesoporous silica(MSN) was prepared by classical St?ber method and MSNion was obtained by doping hydroxyapatite. MH was loaded into MSNion by magnetic stirring, and chitosan (COS), which had anti-inflammatory and antibacterial effect, was adsorbed on its surface by using charge interactions, forming MH@MSNion@COS microspheres. The microspheres were characterized by electron microscopy and X-ray diffraction. The experiments were divided into control, MH, MSNion@COS and MH@MSNion@COS groups. The cytotoxicity of each group was assessed using the CCK-8 cell assay and the optimal concentration was determined. The expression levels of inflammatory factors(TNF-α, IL-6, IL-1β, iNOS, IL-10) were determined in each group using ELISA kits. In periodontitis model, the rats were treated according to the grouping of cell experiments, periodontal probing depth (PD) and gingival index (GI) of the rats were measured at 0, 1, 2, 4 weeks. At 4 weeks of the experiment, the peripheral blood of each group of rats was collected, and the levels of inflammatory factors in serum were detected by ELISA kits.

Results: Nanoparticles with a particle size of about 110 nm were prepared and observed as regular spheres by electron microscopy. MH@MSNion@COS degraded into fragments with unclear structure at the 8th day. In vitro drug release assay showed a slow release of MH, and the MH release rate reached 80% at about the 15th day. In cell experiment, MH@MSNion@COS showed the best cell proliferation activity at 50 μg/mL (P＜0.05), and the cell activity was higher than that of MH group and MSNion@COS group(P＜0.05). There was no significant difference between MH group and MSNion@COS group. ELISA results showed that the expression of inflammatory factors in MH@MSNion@COS group was significantly lower than that in LPS group at the first day(P＜0.01), and there was no significant difference between MH group and MSNion@COS group. At the 3rd day, the expression of M1 inflammatory factors in MH@MSNion@COS group was lower than that in control group, and the expression of M2 inflammatory factors was higher than that in control group(P＜0.05). PD and GI of MH@MSNion@COS group were significantly decreased after administration compared with other groups(P＜0.05), and the amount of inflammatory factors was lower than other groups(P＜0.05).

Conclusions: MH@MSNion@COS has a good inflammatory regulation effect on experimental periodontitis in vitro and in vivo.

Purpose: To evaluate the clinical efficacy of immediate replantation using simple taper fixed implants at failed implantation sites.

Methods: Patients with implant failure at the Department of Stomatology, Fourth Affiliated Hospital of Nanchang University from January 2018 to December 2022 were collected. Simple taper-retained implants were used for immediate replantation at implant failure sites. Marginal bone loss, survival rate and complications were analyzed at immediate replantation(T0), immediately after repair(T1), and at the last follow-up(T2).

Results: A total of 33 implantation failure sites in 31 patients were included at an average of (13.27±21.92) months after primary implantation, 33.33% were early failures and 66.67% were late failures; the average follow-up after immediate reimplantation was (14.22±9.90) months, with an overall retention rate of 100%. History of periodontitis, smoking, systemic diseases, and nocturnal grinding conditions, occlusal relationship, and bone type at the implant site had no significant difference in the effect of peri-implant marginal bone resorption; the difference between the mean implant length and the implant length at primary implantation was not statistically significant, but there was significant difference in the implant diameter and implantation depth between the primary implantation and the reimplantation. Binary Logistic regression model showed that the diameter of the implant had no significant effect on the survival rate of the implant, but the deeper the implant depth, the higher the survival rate of the implant.There was significant bucco-lateral bone height resorption at T0 and T1, but no significant changes in proximal and distal mesial heights, lingual bone heights, and buccolingual bone thickness at T0, T1, and T2. Buccolingual lateral bone height had the least amount of resorption in the T2-T1 period, which was statistically different from the amount of bone resorption in the T1-T0 and T2-T0 periods. Buccolingual lateral bone thickness was statistically different from the amount of bone change in the T1-T0 and T2-T1 periods, but there was no significant change in proximal and distal mesial heights, buccolingual lateral bone heights, and lingual lateral bone thicknesses in the T1-T0, T2-T1, and T2-T0 periods.

Conclusions: The application of simple taper fixed implant system for immediate replantation at failed implant sites has good short-term clinical effects, and immediate replantation can be considered in the event of implant failure.

Purpose: To evaluation the effect of cruciform tooth division and T-type crown amputation in extraction of mandibular middle and low impacted teeth.

Methods: A total of 81 patients with mandibular middle and low impacted teeth treated in Bozhou People's Hospital from September to November 2024 were selected. According to the different extraction methods,they were divided into the control group(n=40, T-type crown amputation) and experimental group(n=41, cross tooth extraction). The operative time, intraoperative complications(anxiety, broken root), postoperative complications (pain, swelling and restricted mouth opening), healing of tooth extraction socket 1 week after surgery, and quality of life before and 1 week after surgery[oral health impact scale 14(OHIP-14)] were compared between the two groups.

Results: The operative time of the experimental group was significantly shorter than that of the control group, the total incidence of intraoperative complications(4.88%) was significantly lower than that of the control group (20.00%), the score of postoperative pain and mouth opening restriction was significantly lower than that of the control group, the degree of postoperative swelling was significantly less than that of the control group, and the total incidence of postoperative complications(4.88%) was significantly lower than that of the control group(32.43%). The healing score of tooth socket 1 week after operation was significantly lower than that of the control group (P＜0.05). One week after surgery,the OHIP-14 score of both groups was decreased,and the experimental group was significantly lower than the control group(P＜0.05).

Conclusions: Compared with T-type crown amputation, cruciform tooth division can shorten the operation time of mandibular middle and low impacted tooth extraction, reduce the occurrence of intraoperative anxiety, broken root, postoperative pain, swelling and restricted mouth opening, and is conducive to the healing of tooth extraction wound.

Purpose: To provide references for the selection of restoration types and materials for the first premolar with large defect in clinical practice.

Methods: A large area defect model of the maxillary first premolar was established and repaired with different types and materials, including group A (inlay group), group B (endocrown group), group C (fiber post core crown group), and group D (pure titanium post core crown group). And then, according to different repair materials, it was divided into 3 subgroups, namely group 1 (zirconia), group 2 (glass ceramic), and group 3 (resin based ceramic), totaling 12 groups. The stress distribution and magnitude were investigated using finite element analysis software.

Results: In the inlay group, the stress concentration area was large and tended to spread along the neck of tooth; in the post core crown group and endocrown group, the stress distribution was more uniform. In terms of restorative materials for endocrown, resin based ceramic materials had the lowest stress, followed by glass ceramic materials, and zirconia materials had the highest stress.

Conclusions: Large defects of the first premolar can be repaired with endocrowns and post core crowns, and endocrowns have good applicability and advantages. Resin based ceramic materials are recommended for the selection of the endocrown materials for the least stress of the remaining tooth.

Purpose: To evaluate the effect of concentrated growth factor (CGF) membrane and Haiao oral repair membrane on the preservation of extraction sites in the posterior area of teeth.

Methods: A total of 96 patients requiring site preservation after posterior tooth extraction from January 2020 to December 2022 were selected and divided into groups A and B by random number table method, with 48 cases in each group. After tooth extraction, Bio-Oss bone powder was used to cover tooth extraction wound in group A with CGF membrane, and in group B with Haiao oral repair membrane. The healing of the operative area, the changes of vertical height and horizontal width of alveolar bone, visual analog scoring (VAS) of pain, the changes of buccal and palatal tissue thickness and the rate of bone replantation were compared between the two groups.

Results: One week after operation, the tooth extraction wound in group A healed well, while 2 cases in group B healed poorly, but there was no significant difference between the two groups(P＞0.05). Before surgery, there was no significant difference in vertical height and horizontal width of alveolar bone between the two groups(P＞0.05); at 6 months after operation, the vertical height of alveolar bone was significantly increased and the horizontal width was significantly decreased(P＜0.05), but there was no significant difference between the two groups(P＞0.05).The VAS score of pain 1 week after surgery in 2 groups was lower than that 3 days and 24 hours after surgery, and the VAS score of pain in group A was lower, and the interaction between groups, and time points were significantly different(P＜0.05).There was no significant difference in the thickness of buccal and palatal tissues between the two groups before and 6 months after surgery(P＞0.05); at 6 months after surgery, the tissue thickness of the palatal side in group B was significantly lower than before surgery(P＜0.05). Six months after surgery, the bone replantation rates in group A and group B were 4.17% and 6.25%, respectively, with no significant difference between the two groups(P＞0.05).

Conclusions: Both CGF membrane and Haiao oral repair membrane have good efficacy in the preservation of tooth extraction sites in the posterior region, which can effectively delay alveolar bone mass absorption, and CGF has a better effect in reducing short-term postoperative pain in patients.

Purpose: To investigate the value of 3D oral scanning combined with digital guide plate in implant restoration of mandibular posterior dentition defect.

Methods: A total of 96 patients with mandibular posterior dentition defects treated in Hangzhou Stomatology Hospital from March 2021 to October 2022 were randomly divided into control group (48 cases) and experimental group (48 cases). The control group was treated with conventional implant repair, while the experimental group was treated with 3D oral scanning combined with digital guide plate implant repair. The operation related indexes, implant accuracy, implant stability, alveolar ridge and parietal bone absorption of the two groups were compared, and the implant success rates, complication rates and patient satisfaction were also evaluated.

Results: There was no significant difference in postoperative pain time and swelling time between the two groups(P＞0.05), but the surgical time in the experimental group was significantly shorter than that in the control group(P＜0.05). The crown deviation, root deviation, depth deviation and angle deviation in the experimental group were significantly smaller than those in the control group(P＜0.05). The success rate of the experimental group was significantly higher than that of the control group(P＜0.05). There was no statistically significant difference in the planting success rate and stability coefficient between the two groups(P＞0.05), and the absorption of alveolar crest bone in the experimental group was significantly lower than that in the control group(P＜0.05). The total incidence of complications in the experimental group was significantly lower than that in the control group (P＜0.05). The satisfaction of patients in the experimental group was significantly higher than that in the control group(P＜0.05).

Conclusions: The application of 3D oral scanning combined with digital guide plate in implant restoration of mandibular posterior dentition defect can effectively shorten the operation time, improve the accuracy of implant, reduce the complications, and improve patients' satisfaction.