The impact of susceptibility correction on diffusion metrics in adolescents.

BACKGROUND: Diffusion tensor imaging is a widely used imaging method of brain white matter, but it is prone to imaging artifacts. The data corrections can affect the measured values. OBJECTIVE: To explore the impact of susceptibility correction on diffusion metrics. MATERIALS AND METHODS: A cohort of 27 healthy adolescents (18 boys, 9 girls, mean age 12.7 years) underwent 3-T MRI, and we collected two diffusion data sets (anterior-posterior). The data were processed both with and without susceptibility artifact correction. We derived fractional anisotropy, mean diffusivity and histogram data of fiber length distribution from both the corrected and uncorrected data, which were collected from the corpus callosum, corticospinal tract and cingulum bilaterally. RESULTS: Fractional anisotropy and mean diffusivity values significantly differed when comparing the pathways in all measured tracts. The fractional anisotropy values were lower and the mean diffusivity values higher in the susceptibility-corrected data than in the uncorrected data. We found a significant difference in total tract length in the corpus callosum and the corticospinal tract. CONCLUSION: This study indicates that susceptibility correction has a significant effect on measured fractional anisotropy, and on mean diffusivity values and tract lengths. To receive reliable and comparable results, the correction should be used systematically.

Survival of Autotransplanted Teeth With Open Apices: A Retrospective Cohort Study.

PURPOSE: Autotransplantation of teeth is an alternative treatment method in growing patients with hypodontia or impacted teeth. The purpose of the present study was to investigate the occurrence of, and predictors for, the loss of transplanted teeth in children and young adults. PATIENTS AND METHODS: All patients who had undergone tooth transplantation at the Department of Oral and Maxillofacial Surgery, Turku University Hospital, from October 1, 2009 to January 5, 2017, were identified from the hospital's database. The outcome variable was survival of the transplanted tooth. The predictor variables were the transplantation type, donor tooth, maturity of the donor tooth, number of roots of the donor tooth, recipient's jaw, the need for extraoral storage of the donor tooth during surgery, continuation of root development during follow-up, and institution experience. One tooth was randomly selected from each subject. The Kaplan-Meier method for survival analysis, and the Cox proportional hazards regression analysis results were used to assess the association between survival and the risk factors. RESULTS: The sample included 36 subjects with a mean age of 14.3 years; 33.3% were male, 45 teeth were transplanted, and the median follow-up time was 1.3 years. The 1-year survival rate was 87% (95% confidence interval [CI], 75 to 99%). A significant predictor for tooth survival was the continuation of root development (hazard ratio, 21.3; 95% CI, 2.1 to 215.0; P = .009). Although not statistically significantly, more favorable prognoses were found for distant than for transalveolar transplantations, 1-rooted than multirooted teeth, premolars than molars, teeth not stored in an extraoral media, and teeth that had been transplanted later during the study period. CONCLUSIONS: The experience of the professional team, use of open apex premolars, and postoperative continuation of root development of the transplant were the factors associated with favorable outcomes. Transplants could benefit from the use of 3-dimensional models during surgery.

Advanced dental maturity of Finnish 6- to 12-yr-old children is associated with high energy intake.

We studied the association of dental maturity with body mass index (BMI), energy intake, and macronutrient intake. A randomly selected subset (n = 148) of the Special Turku Coronary Risk Factor Intervention Project (STRIP) was invited to an oral follow-up study, and the 6- and 12-yr-examination data (n = 111, 60 boys) were used. Food records for four consecutive days and BMI values were extracted from the databank of the main STRIP project. The developmental stage of seven permanent mandibular teeth was assessed using panoramic radiographs. The resulting maturity scores were converted to dental age estimates. Three dental-maturity groups (delayed, average, and advanced) and two BMI groups [normal BMI (≤mean+1SD) and high BMI (>mean+1SD)] were formed. The dental age was higher than the chronological age by 0.6-0.8 yr. Maturity scores for girls were statistically significantly higher than for boys. The distribution of girls into dental-maturity groups at age 12 yr was different from that of the boys and there were more boys than girls among the high-BMI group. Children of the advanced dental-maturity group had a statistically significantly higher energy intake than children in the other groups. We conclude that advanced dental maturity is associated with higher energy intake.

Dental age in patients with neurofibromatosis 1.

Neurofibromatosis type 1 (NF1) is a common, hereditary, neurocutaneous skeletal condition with a variety of osseous manifestations. Although NF1 also affects craniofacial structures, the literature has only limited information related to the effect of NF1 on dental development. In this study the dental age of 34 Finnish NF1 patients, 8-17 yr of age, was estimated using the Demirjian & Goldstein method. The dental age of children with NF1 was similar to that of a Finnish control population. The findings suggest that NF1 does not affect the timing of tooth development.