Frontal fibrosing alopecia is a primary lymphocytic cicatricial alopecia, and is generally considered to be a subtype of lichen planopilaris due to similar histopathological changes. Its etiology is still unclear. With the deepening of research on this disease, more and more cases of frontal fibrosing alopecia have been reported in China and other countries. This review summarizes research progress in pathogenesis, clinical and pathological characteristics, and treatment of frontal fibrosing alopecia.

Objective This study aimed to evaluate the thickening of sinus membrane,which is also named Sch-neiderian membrane(SM),in patients and its relationship with periapical lesions(PAL)in the posterior maxillary region to provide reference for the prevention and treatment of odontogenic maxillary sinusitis.Methods A retrospective anal-ysis was conducted on 554 cone beam computed tomography(CBCT)imaging data of maxillary sinuses from 301 pa-tients who met the inclusion criteria to determine the correlation between PAL and SM thickening in the posterior maxil-lary region.Cases of pathological SM were recorded and classified on the basis of the degree and type of SM thickening.The correlation between SM thickening and the diameter of PAL,the relationship between the upper edge of PAL and the maxillary sinus floor,and its relationship with whether affected teeth with PAL undergo root canal treat-ment were evaluated.Results The detection rate of SM thickening in patients with PAL was significantly higher than in those without PAL,so PAL was correlated with SM thickening.Analysis on the correlation between PAL detection indi-cators and SM thickening degree showed that SM thickening degree was positively correlated with PAL diameter(cone beam computed tomography-periapical index)and not correlated with the three spread effects between the upper edge of PAL and the maxillary sinus floor,as well as whether the teeth with PAL undergo root canal treatment.The correlation analysis between PAL detection indicators and SM thickening types showed that whether the teeth with PAL undergo root canal treatment was not correlated with SM thickening types,and the diameter of PAL,the three spread effects be-tween the upper edge of PAL,and the maxillary sinus floor were not correlated with SM thickening types.Conclusion The PAL of posterior maxillary teeth is closely related to SM thickening,and the diameter of PAL is positively correlated with the degree of SM thickening.Patients with PAL who have undergone root canal treatment often exhibit SM polyp thickening.In addition,the relationship between the upper edge of PAL and the maxillary sinus floor does not affect the possibility of SM development.

OBJECTIVES: This study aimed to evaluate the efficacy of three methods in root canal retreatment to remove the filling material in the root canals. METHODS: Ninety tooth roots filled by gutta percha or plasticized material (n=45, each) were randomly divided into three groups (n=15). WaveOne (WaveOne group), 1^#P drill+WaveOne (1^#P+WaveOne group), and ultrasound P5 working end ET25+ProTaper Universal (P5+ProTaper Universal group) were used to remove the root canal filling material and prepare for root canal. The operating time of each canal was recorded and the percentage of residual filling material area was measured on the root canal wall of the mesial and distal dissected root section. The degree of deviation of the root canal after operation was measured for the root samples filled by gutta percha. RESULTS: The type of root filling material and the method of root canal retreatment had no significant effect on the percentage of residual area of the filling material (P>0.05). However, the remaining filling material area of apical 1/3 of the root canal was significantly higher than that of cervical 1/3 of the root canal (P<0.05). The average operating times for removing gutta-percha or plasticized material in the W and 1^#P+WaveOne groups were significantly less than that in the P5+ProTaper Universal group (P=0.000). The root canal retreatment methods had no significant effect on the curvature of the root canal (P=0.650). CONCLUSIONS WaveOne single file's cleaning ability and center positioning ability were similar to those of ProTaper Universal. Moreover, WaveOne can be independently used for most root canals without a pathway when removing the root canal fillings, thereby simplifying the process of root canal retreatment.
Equipment Design ; Gutta-Percha ; Nickel ; Root Canal Filling Materials ; Root Canal Preparation/methods* ; Titanium