Radiographic analysis of critical anatomical structures for pterygoid implant placement in Chinese patients with a severely atrophied maxilla.

The pterygoid implant is a feasible alternative for posterior dental rehabilitation without grafting; however, the ideal pterygoid implant placement continues to be debated. The aim of this study was to identify effective landmarks and establish valid guidelines to determine the ideal pterygoid implant placement. Cone beam computed tomography (CBCT) data of 100 severely atrophied maxillae requiring implant rehabilitation, obtained between January 2015 and December 2018, were included. The CBCT data were obtained in DICOM format from the radiographic database and imported into Nobel Clinician software (Nobel Biocare) for radiographic analysis. Virtual pterygoid implant placement was successful in 67 maxillae: a 13-mm virtual implant in four maxillae (6.0%), 15-mm in 52 maxillae (77.6%), and 18-mm in 11 maxillae (16.4%). For the virtual pterygoid implant, the mean implant angulation± standard deviation in the anteroposterior axis (sagittal view) was 45.08 ± 2.56° relative to the Frankfort plane. In the buccopalatal axis (coronal view), the mean implant angulation was 64.30 ± 4.99° relative to the Frankfort plane and the mean value for the shortest linear distance between the palatine canal and apical tip of the virtual implant was 3.91 ± 0.62 mm. A 15-mm pterygoid implant placed at 45° in the anteroposterior axis and 60° in the buccopalatal axis (relative to the Frankfort plane), is generally recommended in this Chinese patient population.

[Effects of the injectable glycol-chitosan based hydrogel on the proliferation and differentiation of human dental pulp cells].

OBJECTIVE: To prepare glycol-chitosan (GC)-based single/dual-network hydrogels with different composition ratios (GC31, DN3131 and DN6262) and to investigate the effects of hydrogel scaffolds on biological behavior of human dental pulp cell (hDPC) encapsulated. METHODS: GC-based single-network hydrogels (GC31) and GC-based dual-network hydrogels (DN3131, DN6262) with different composition ratios were prepared. The injectability was defined as the average time needed to expel a certain volume of hydrogel under a constant force. The degradation of the hydrogel was determined by the weight loss with time. The fracture stress was measured using a universal testing machine. The proliferation of hDPCs in hydrogels was detected using the cell counting kit-8 (CCK-8) method and CalceinAM/PI Live/Dead assay. After 14 days of odontoblastic induction, the expression of alkaline phosphatase (ALP), dentin sialophosphoprotein (DSPP) and dentin matrix protein-1 (DMP-1) was detected by real-time quantitative reverse transcription PCR (real-time RT-PCR) and the mineralized nodules was observed by Von Kossa staining. RESULTS: The injectability of all three groups of hydrogels was acceptable. The time of injection of GC31 was the shortest, and that of DN6262 was longer than DN3131 (P<0.05). The degradation rate of GC31 hydrogel in vitro was significantly faster than that of the dual-network hydrogel groups (P<0.05). There was no significant difference between DN3131 and DN6262 (P>0.05). The compressive resistance failure point of GC31 group was 1.10 kPa, while it was 7.33 kPa and 43.30 kPa for DN3131 and DN6262. The compressive strength of dual-network hydrogel was significantly enhanced compared with single-network hydrogel. hDPCs were in continuous proliferation in all the three groups, and the GC31 group showed a higher proliferation rate (P<0.05). The expression levels of DSPP, DMP-1 and ALP in the dual-network hydrogel groups (DN3131, DN6262) were significantly higher than that of GC31 after culturing for 14 days (P<0.05), there was no difference in the expression levels of DMP-1 and ALP between DN3131 and DN6262 (P>0.05); Von Kossa staining showed that more mineralization deposition and mass-shaped mineralized nodules formed in DN3131 and DN6262, while only light brown calcium deposition staining was observed in GC31 group, which was scattered in granular forms. CONCLUSION: GC-based single/dual network hydrogels with different composition ratios met the injectable requirements. GC31 group had a lower mechanical properties, in which hDPCs exhibited a higher proliferation rate. dual-network hydrogels had slower degradation rate and higher mechanical properties, in which hDPCs exhibited better odontoblastic differentiation potential and mineralization potential.

[Application of polymerase chain reaction in the diagnosis of gonococcal urethritis].

84 suspected patients with gonococcal urethritis were diagnosed by polymerase chain reaction (PCR). It was demonstrated that 28 patients (33.3%) were positive, and 56 (66.7%) negative. Of the PCR-positive patients, 18 showed secretions from the urethral tract, on which the bacterial stain and culture were carried out. The results indicate that 12 patients were positive, and 6 negative. There was no patient with positive stain and culture with PCR-negative. We conclude that PCR is more specific and sensitive than other routine methods in the diagnosis of gonococcal urethritis, especially of chronic infection.