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Objective: To compare the alveolar bone thickness of mandibular incisors in individuals with mandibular low-, average-, and high- angle skeletal patterns BEFORE orthodontic treatment, to measure alveolar bone loss and root resorption of mandibular incisors in the three skeletal patterns AFTER orthodontic treatment, and to link condylar morphology to the different skeletal patterns, using cone-beam computed tomography. Methods: Pretreatment CBCT images of 75 non-growing individuals, 25 in each of 3 groups: low-angle (SN-MP , average- angle (30-37 , and high-angle (≥39 , were analyzed. Buccal-lingual bone thickness was measured at the root apex, mid-root, and at the alveolar crest of the mandibular right central incisor. Post-treatment CBCT images of 11 low-angle, 20 average-angle, and 27 high-angle patients were compared to their pre-treatment images to determine changes in the alveolus and mandibular incisor after orthodontic treatment. 20 pre-treatment CBCTs in each skeletal group were also evaluated to characterize their pre-existing temporomandibular joint morphology.Results: ANOVA test showed that the buccal-lingual width at the apex of the mandibular incisor was significantly different between the three groups (p-value=0.000). A Bonferroni correction showed that the bone supporting the mandibular incisor in low-angle individuals was significantly thicker than that of average and high-angle individuals (p-value=0.000), but that the difference was not significant between those with average and high angles (p-value=0.059). The pretreatment TMJ evaluation indicated that high angle subjects had a higher prevalence of signs of degenerative joint disease, but this difference was not statistically significant (Fisher's exact, p = 0.09). Evaluation of post-treatment changes showed that high-angle subjects had more external root resorption when compared to those with average and low-angles, but the buccal-lingual bone thickness changes were minimal (ranged from 0.24mm to 0.58mm). Conclusions: Negative sequelae of orthodontic treatment is more frequently found in individuals with high-mandibular plane angle, and could be linked to their thin pre-existing mandibular buccal-lingual widths. Individuals with a narrow alveolar ridge have a narrow envelope in which teeth can be moved safely.

BACKGROUND: Maternal nutritional status is an important predictor of infant birthweight. Most previous attempts to improve birthweight through multiple micronutrient supplementation have been initiated after women are pregnant. Interventions to improve maternal nutritional status prior to conception may be more effective in preventing low birthweight and improving other infant health outcomes. OBJECTIVE: To compare the effects of maternal supplementation with animal-source food from preconception to term or from mid-gestation to term with routine prenatal care on birthweight the prevalence of preterm births intrauterine growth restriction and infant growth during the first 12 months of life and on maternal nutrient status and the incidence of maternal and infant infections. METHODS: Young women from 29 rural communes in northwestern Vietnam were recruited when they registered to marry and were randomized to one of three interventions: animal-source food supplement 5 days per week from marriage to term (approximately 13 months) animal-source food supplement 5 days per week from 16 weeks of gestation to term (approximately 5 months) or routine prenatal care without supplementalfeeding. Data on infant birthweight and gestational age maternal and infant anthropometry micronutrient status and infections in the infant and mother were collected at various time points. RESULTS: In a preliminary study of women of reproductive age in this area of Vietnam 40% of the women were underweight (body mass index < 18.5) and anemic. About 50% had infections. Rice was the dietary staple and nutrient-rich animal-source foods were rarely consumed by women. Iron zinc vitamin A folate and vitamin B12 intakes were inadequate in about 40% of the women. The study is still ongoing and further data are not yet available. CONCLUSIONS: The results of this study will provide important data regarding whether improved intake of micronutrient-rich animal-source foods that are locally available and affordable before and during pregnancy improves maternal and infant health and development. This food-based approach may have global implications regarding how and when to initiate sustainable nutritional interventions to improve maternal and infant health.