Meta-analysis of the efficacy of invisible orthodontic appliances for maxillary molar distalization in adult patients / 口腔疾病防治

Objective@#To evaluate the clinical efficacy of invisible orthodontic appliances without brackets for the distal movement of maxillary molars to improve the ability of orthodontists to predict treatment outcomes.@*Methods@#Web of Science, Cochrane Library, Embase, PubMed, Wanfang Database, CNKI Database, and VIP Database were searched for studies investigating the efficacy of invisible orthodontic appliances for distal movement of maxillary molars in adult patients and published from database inception to August 1, 2023. A total of three researchers screened the studies and evaluated their quality and conducted a meta-analysis of those that met quality standards.@*Results@#This study included 13 pre- and postcontrol trials with a total sample size of 281 patients. The meta-analysis revealed no significant differences in the sagittal or vertical parameters of the jawbone after treatment when compared with those before treatment (P>0.05). The displacement of the first molar was MD=-2.34, 95% CI (-2.83, -1.85); the displacement was MD=-0.95, 95% CI (-1.34, -0.56); and the inclination was MD=-2.51, 95% CI (-3.56, -1.46). There was a statistically significant difference in the change in sagittal, vertical, and axial tilt of the first molar before and after treatment. After treatment, the average adduction distance of the incisors was MD=-0.82, 95% CI (-1.54, -0.09), and the decrease in lip inclination was MD=-1.61, 95% CI (-2.86, -0.36); these values were significantly different from those before treatment (P<0.05).@*Conclusion@#Invisible orthodontic appliances can effectively move the upper molars in a distal direction and control the vertical position of the molars. When the molars move further away, there is some degree of compression and distal tilt movement, which is beneficial for patients with high angles. The sagittal movement of incisors is beneficial for improving the patient's profile.

Time-course changes of intraosseous environment and shear resistance mechanical properties of jawbone in SD rats with fluorosis / 环境与职业医学

Background At present, a large number of reports focus on the bones of limbs and trunk, while there are few studies on the effect of fluorosis on jawbone which is the inevitable structural basis for the development and treatment of oral diseases. Objective To preliminarily investigate the effect of fluoride exposure on the mechanical properties of jawbone by observing the changes in the intraosseous environment and the maximum load against shearing force (LSFmax) of the jawbone in rats with chronic fluoride treatment. Methods Screening experiment: 48 SD male rats were randomly divided into a control group and three fluoride exposure groups (50, 150, and 250 mg·L−1 fluoride concentration), 12 rats in each group. The fluoride exposure groups were molded by feeding different concentrations of sodium fluoride solution, and the control group drank tap water from Guizhou area. Each group was further divided into 4 subgroups with 3 animals each according to observation time points after 0, 2, 4, and 6 months. The LSFmax of the jawbone was measured with an electronic universal ergometer, the expression of type I collagen (Col1) was shown by Sirius red staining, and the expression of runt-related transcription factor 2 (Runx2) was determined semi-quantitatively by immunohistochemistry at selected time points. Formal experiment: 12 male SD rats were randomly divided into a fluoride exposure group and a control group. The fluoride exposure group were fed with 150 mg·L−1 sodium fluoride solution, and the control group drank tap water from Guizhou. After feeding with fluoride for 5 months, the ergometer was used to measure the LSFmax of the jawbone. Osteoclasts were counted after tartrate resistant acid phosphatase (TRAP) staining. Col1, Runx2, bone morphogenetic protein 2 (BMP-2), alkaline phosphatase (ALP), and cathepsin K (Cath K) were detected semi-quantitatively by immunohistochemistry expression and Sirius red staining. Micro computed tomography (Micro CT) was used to observe the trabecular bone microstructure. Results Screening experiment: The LSFmax of the control group and the 50 mg·L−1 fluoride exposure group reached the peak value at the 2nd month, and the LSFmax of the 50 mg·L−1 fluoride exposure group reached the valley value at the 4th month. The LSFmax of the 150 mg·L−1 fluoride exposure group at the 4th month was higher than that at the 6th month (P<0.05). There was no significant difference in the LSFmax at each time point in the 250 mg·L−1 fluoride exposure group. At the same time point, there was no statistically significant difference in LSFmax among the groups. The Col1 levels of the 50 mg·L−1, 150 mg·L−1, and 250 mg·L−1 fluoride exposure groups were higher than the time point 0 from the 2nd month (P＜0.05). The Runx2 showed no statistically significant difference by concentration or time. Formal experiment: After feeding with 150 mg·L−1 fluoride for 5 months, the LSFmax of the fluoride exposure group was greater than that of the control group (P<0.05). The expressions of Col1, Runx2, BMP2, ALP, and Cath K in the fluorosis exposure group were higher than those in the control group (P<0.05). There were no statistically significant differences in osteoclast count or indicators of bone trabecular microstructure. Conclusion Chronic fluoride exposure may increase the shear strength of jaw bone.

Aggressive central giant cell granuloma of the mandible: A case report and review of literature

Mandibular aggressive central giant cell granuloma is a rare non-neoplastic giant cell tumour characterised by pain, bone destruction, tooth root resorption, jawbone cortical perforation, and high recurrence rate. This is a case of a 10-year-old boy who presented to the Dental Surgical outpatient clinic of University of Uyo Teaching Hospital with a three-year history of left jaw swelling. The clinical diagnosis was fibrous dysplasia of the left hemi-mandible. Consequently, left hemi-mandibulectomy was performed, and subsequent histopathological diagnosis was aggressive central giant cell granuloma of the mandible. This article presents this rare diagnosis and explores its classification, aetiopathogenesis, clinico-pathological features and management.

Comparative study on fluoride accumulation in hard tissues of rats with chronic drinking-water-borne fluorosis / 环境与职业医学

Background A large number of studies on fluoride-induced systemic bone damage have been reported previously, but there is little understanding of the characteristics of fluoride accumulation in jawbone. Jawbone is homologous to the other bone tissues in the body, and is an indispensable and important frame structure in the oral cavity. Objective To study fluoride accumulation and its change trends in teeth, jawbone, and femur of SD rats with chronic drinking-water-borne fluorosis. Methods A total of 144 three-week-old SD rats, half male and half female, were randomly divided into two groups, a normal control group and a fluoride group. The rats in the normal controlgroup drank purified water disinfected and filtered from Guizhou, and the water contained 0.08 mg·kg−1 fluoride which was lower than the national water quality standard at 1 mg·kg−1. The rats in the fluoride group were fed with sodium fluoride (NaF) solution with a concentration of 150 mg·L−1. At 3, 5 and 7 months of the fluoride exposure, the levels of fluoride in urine, blood, teeth, jawbone, and femur were measured by fluoride ion electrode method. Results There was no sex difference in fluoride content in different biological samples of rats in the fluoride group and the normal control group (all P>0.05). After 3 months of fluoride exposure, the rats in the fluoride group showed dental fluorosis of grade II, and higher levels of fluoride ion in blood and urine than the normal control group (all P<0.05), indicating that the rat model of fluoride drinking-water-borne chronic fluorosis was successfully replicated. In the normal control group, the levels of fluoride in femur remained stable; at the end of 3 months, the levels of fluoride in jawbone and teeth were (1097.36±470.34) and (453.09±173.43) mg·kg−1 respectively, and at the end of 7 months, the levels of fluoride in jawbone and teeth were (2113.18±634.49) and (1604.80±160.43) mg·kg−1 respectively. Both jawbone and teeth showed a positive temporal effect of increasing fluoride accumulation (P<0.05). After continuous fluoride feeding, the fluoride levels in jawbone, teeth, and femur of rats in the fluoride group were (3145.02±765.82), (1550.20±77.73), and (3640.55±699.42) mg·kg−1 after 3 months, and (8420.36±1728.56), (4702.08±1417.06), and (6091.99±1384.97) mg·kg−1 after 7 months. The three kinds of hard tissues all showed a positive temporal effect of increasing fluoride accumulation (P<0.05), and the cumulative increas was large than that in the normal control group. Among them, jawbone fluorine increased most. At the end of 5 months, the levels of fluoride in jawbone, femur, and teeth were (6485.02±2141.98), (4914.99±1529.41), and (3365.21±1462.27) mg·kg−1 respectively, and the levels of fluoride in jawbone was much higher than those in femur and teeth (P<0.05). Conclusion Hard tissues such as bones and teeth are fluorine sensitive tissues. Compared with femur, jawbone showed significantly high fluoride accumulation, while teeth show relatively lagging fluoride accumulation.

Clinical thinking and evidence-based for decompression of cystic lesions in the jaw bone / 口腔疾病防治

@#Decompression is an effective and widely used treatment for jawbone cystic lesions that can, to a great extent, preserve the function and appearance of the jawbone. However, some problems exist with its clinical application, such as the inappropriate determination of indication and the lack of standardized operational guidelines, resulting in treatment ineffectiveness or even failure. This paper aimed to summarize the clinical value of decompression for jawbone cystic lesions in terms of mechanism, scientific evidence, advancement, indications and effective evaluation by reviewing relevant literature and our clinical experience.

In Vitro Osteogenic Differentiation of Human Mesenchymal Stem Cells from Jawbone Compared with Dental Tissue

Autologous bone transplantation is the current gold standard for reconstruction of jawbone defects. Bone regeneration usingmesenchymal stem cells (MSC) is an interesting alternative to improve the current techniques,which necessitate a second site of surgery resulting in donor site morbidity. In this study,we compared the osteogenic ability of jawboneMSC(JB-MSC) withMSC from tissues with neural crest origin, namely, the dental pulp, apical papilla and periodontal ligament. All four types ofMSC were isolated from the same patient (n = 3 donors) to exclude inter-individual variations.TheMSCgrowth and differentiation properties were characterized. The osteogenic differentiation potential in each group of cells was assessed quantitatively to determine if there were any differences between the cell types. All cells expressed the MSC-associated surface markers CD73, CD90, CD105, and CD146 and were negative for CD11b, CD19, CD34, CD45 and HLA-DR. All cell types proliferated at similar rates, exhibited similar clonogenic activity and could differentiate into adipocytes and osteoblasts. An alkaline phosphatase assay, OsteoImage™ assay for mineralization and qRT-PCR measuring the genes runx2, ALP and OCN, indicated that there were no significant differences in the osteogenic differentiation ability between the variousMSCs. In conclusion,we show that from a small segment of jawbone it is possible to isolate sufficient quantities of MSC and that these cells can easily be expanded and differentiated into osteoblasts. JB-MSC appear to be good candidates for future bone regeneration applications in the craniofacial region.