Longitudinal Quantitation of Tooth Displacement in Chinese Adolescents with Normal Occlusion

This longitudinal study aims to analyze the different modes of the maxillary and mandibular tooth displacement in subjects,who were aged 12.5-17.5 years(150-210 months),with untreated normal(Class I)occlusion.Longitudinal lateral cephalograms for a set of 10 subjects(7 females and 3 males)at consecutive annual time points were selected and monitored.Data were analyzed on the basis of the superimpositions of serial tracings of lateral cephalograms on stable anterior cranial base,the anatomies of the maxillary and mandibular structures.The horizontal and vertical displacements of the first molar and incisor were assessed by r-test.The local and the secondary tooth displacements with growth contributed to the total horizontal and vertical displacements of the molars and incisors of the subjects.In the total tooth displacement,the horizontal growth of maxilla and mandible had the same contribution as the local tooth displacements.The vertical maxillary growth played a smaller role than the local drift,and mandibular remodeling went in a reverse direction with the local tooth drift.The first molars moved more forward than the incisors in the upper and lower arches.Both the upper and lower first molars showed forward tipping.The analysis of tooth displacement may be utilized in making orthodontic treatment plan,including anchorage or torque control.

The role of genotype and diet in shaping gut microbiome in a genetic vitamin A deficient mouse model

Multifactors have been reported to affect the gut microbiome, including genotype, age, diet, and nutrition.However, few reports have investigated the relative capacity of different factors to shape the gut microbiome in a single study. Our design used a genetic vitamin A-deficient mouse model, the Rbp4^(-/-)mouse,feeding with the low vitamin A diets at different ages of initiation(4 or 7 weeks) for 28 days. Fecal samples were collected for bacterial profiling at seven time points after diet controlling. With Rbp4 depletion,Akkermansia decreased and Bacteroides increased, whereas Desulfovibrio, Barnesiella, Clostridium_Xl Va,and Lactobacillus fluctuated. The bacterial community swiftly adjusted with the vitamin A-deficient diet administration and gradually changed(e.g., decrease of Barnesiella and increase of Desulfovibrio). Age exerted a relatively weaker but long-last influence. At an earlier age to feed a vitamin A-deficient diet, a higher microbial dysbiosis index will be valued. Of note, the shaping effects of diet and age on the bacterial community varied with the difference of genotype, which might indicate a greater role of genotype than diet and age in shaping the gut microbiome.