[Effects of cortical bone thickness and jaw bone density on pain during implant surgery].

PURPOSE: To investigate the effects of different cortical bone thickness and jaw bone density at implant sites on intraoperative pain during implant surgery. METHODS: One hundred and eighty-seven patients(263 implant sites) who underwent implant placement surgery at the Fourth Affiliated Hospital of Nanchang University from August 2021 to August 2022 were selected to investigate the effects of different cortical bone thickness and jaw bone density HU values at implant sites on the anesthetic effect under local infiltration anesthesia with epinephrine in articaine. SPSS 26.0 software package was used for data analysis. RESULTS: The mean cortical bone thickness at the painful sites[(3.90±1.36) mm] was significantly greater than that at the non-painful sites [(2.24±0.66) mm], and the difference was statistically significant(P＜0.05). The differences in cortical bone thickness in the mandibular anterior, premolar, and molar regions were statistically significant in the comparison of pain and non-pain sites. The mean HU value of bone density was (764.46±239.75) for the painful sites and (612.23±235.31) for the non-painful sites, with significant difference(P＜0.05). The difference was not significant(P＞0.05) when comparing the HU values of painful sites with non-painful sites in the mandibular anterior teeth and anterior molar region, while the difference was significant(P＜0.05) when comparing the HU values of painful sites with non-painful sites in the mandibular molar region. CONCLUSIONS: Sites with large cortical bone thickness have a greater effect on blocking infiltrative anesthetic penetration and are more prone to intraoperative pain during implantation. In the mandibular anterior and premolar regions, the HU value of the implant sites had less effect on infiltrative anesthetic penetration, and the effect was greater in the mandibular molar region, and the implant sites with high HU values in the mandibular molar region were more likely to have intraoperative pain. When the cortical bone thickness in the planned implant site is greater than 3.9 mm and the mean bone density in the mandibular molar region is greater than 665 HU. If there is sufficient safe distance for hole operation, it is recommended to apply mandibular nerve block anesthesia combined with articaine infiltration anesthesia to avoid intraoperative pain and bad surgical experience for the patients.

[Analysis of clinical effects and risk factors of short implant followed up for 7-9 years].

PURPOSE: To evaluate the long-term clinical efficacy of short implants and analyze the influencing factors of the survival rate. METHODS: A total of 178 patients who received implant therapy in the Department of Stomatology, the Fourth Affiliated Hospital of Nanchang University from January 2010 to December 2014 were selected, including 334 short implants of Bicon (implant length ≤6 mm). The basic condition, restoration design, short implant survival rate and complications were observed and analyzed. SPSS 24.0 software package was used for data analysis. RESULTS: The average follow-up time of short implants was 96±17 months. During the observation period, 20 implants failed, 1 implant had mechanical complications and 6 implants had biological complications. Based on the analysis of implants and patients, the long-term cumulative survival rate of short implants was 94.0%(over 5 years survival rate was 96.4%) and 90.4% respectively. There was no significant difference between the survival rate of short implants and the patient's gender, age, whether to use special operation and the type of jaw teeth(P＜0.05). Smoking and periodontitis were risk factors for failure of short implants(P＜0.05).The difference of short implant survival rate between short implants restoration with combined crowns and single crowns was statistically significant(P＜0.05). The survival rate of short implant in mandible was higher than that in maxilla(P＜0.05). CONCLUSIONS: Under the standards clinical program and operation, short implant can be used to shorten the implant restoration cycle and avoid complicated bone augmentation which can achieve good long-term clinical effect. Short implant should be used to strictly control the risk factors that affect the survival of short implant.

[Retrospective study on transcrestal sinus floor elevation with simultaneous implantation of short implants].

OBJECTIVE: To explore the changes in bone height of the maxillary sinus floor at different sinus ridge heights after transcrestal sinus floor elevation (tSFE) with the simultaneous implantation of short implants. METHODS: A total of 74 Bicon short implants were implanted into 37 patients during the same period of maxillary sinus elevation. The residual bone height (RBH)<4 mm group has 43 sites, and the RBH≥4 mm group has 31 sites. After 5 years of follow-up observation, the implant survival rate and the change in bone height achieved in the maxillary sinus over time were measured and analyzed via clinical examination and X-ray imaging. RESULTS: In the 74 implantation sites, the elevation height of the sinus floor was (6.64±1.32) mm and the bone height of the sinus floor was (3.35±1.29) mm 5 years after loading. No statistical difference was observed in the bone resorption of the implant neck between the RBH<4 mm and RBH≥4 mm groups. Meanwhile, a statistical difference was noted in the bone height obtained in the maxillary sinus between the two groups. CONCLUSIONS: When RBH in the maxillary posterior tooth area was <4 mm, the simultaneous implantation of Bicon short implants with tSFE can achieve a high implant survival rate and bone gain in the maxillary sinus, but does not increase the absorption of the alveolar ridge bone.

An experimental model for induction of lung cancer in rats by Chlamydia pneumoniae.

OBJECTIVE: To assess induction effects of Chlamydia pneumoniae (Cpn) on lung cancer in rats. METHODS: A lung cancer animal model was developed through repeated intratracheal injection of Cpn (TW-183) into the lungs of rats, with or without exposure to benzo(a)pyrene (Bp). Cpn antibodies (Cpn-IgA, -IgG, and -IgM) in serum were measured by microimmunofluorescence. Cpn-DNA or Cpn-Ag of rat lung cancer was detected through polymerase chain reaction or enzyme-linked immunosorbent assay. RESULTS: The prevalence of Cpn infection was 72.9% (35/48) in the Cpn group and 76.7% (33/43) in the Cpn plus benzo(a)pyrene (Bp) group, with incidences of lung carcinomas in the two groups of 14.6% (7/48) and 44.2% (19/43), respectively (P-values 0.001 and <0.001 compared with normal controls). CONCLUSIONS: A rat model of lung carcinoma induced by Cpn infection was successfully established in the laboratory for future studies on the treatment, prevention, and mechanisms of the disease.