Do the miniscrews of the prefabricated systems for the "appliance first" protocol of miniscrew-assisted rapid palatal expansion have lengths that meet the palatal thickness of patients?

INTRODUCTION: In the "appliance first" protocol of miniscrew-assisted rapid palatal expansion, the prefabricated shape of the expanders limits the potential locations for miniscrew placement. Considering the influence of palatal thickness on the selection of the optimal length of miniscrews, this study aimed to evaluate the thickness of both bone and mucosa of the palate of patients aged 6-65 years and suggest optimal lengths of miniscrews for this approach. METHODS: Two hundred and eighty-two cone-beam computed tomography of patients of both sexes were divided into 3 groups according to age. The thicknesses of bone and mucosa were measured in the anterior and posterior regions of the palate. RESULTS: Males showed a greater thickness of palatal bone than females. The thickness of both bone and mucosa was greater in the anterior region of the palate. The young patients showed greater bone thickness than adults and mature adults. The mature adults showed thinner bone thickness in the posterior region of the palate and greater mucosal thickness along the palate than young patients and adults. Development of miniscrews with longer thread lengths is necessary. Miniscrews with a 3-mm thread length would prevent excessive extravasation in the posterior region of the palate. CONCLUSIONS: The thickness of both bone and mucosa of the palate is variable and influenced by sex and age. Manufacturing additional miniscrews with different lengths of thread is suggested to achieve bicortical anchorage in patients undergoing the "appliance first" protocol of miniscrew-assisted rapid palatal expansion.

Prevalence of malocclusions in children with microcephaly associated with the Zika virus.

INTRODUCTION: The objectives of this study were to determine the prevalence of malocclusion among children with Zika virus-associated microcephaly (MZV) and to describe the most common malocclusion in this population. METHODS: This was a cross-sectional study including patients aged between 30 and 36 months diagnosed with MZV. Healthy children were randomly selected with the same sociodemographic characteristics as the control group. Information about arch-type, primate spaces, arch form, overbite, overjet, midline deviation, anterior crossbite, anterior open bite, and the posterior crossbite was recorded. The statistical analysis used descriptive analysis, Pearson chi-square test, and multivariate logistic regression. RESULTS: Forty children comprised the MZV group, and 40 comprised the control group. Our results demonstrated a significantly higher prevalence of malocclusions in children who had MZV than the control group (P <0.001). Patients with MZV were more likely to have late eruption (P <0.001), hypoplastic maxillary arch (P <0.001), hypoplastic mandibular arch (P <0.001), excessive overjet (P <0.001), and posterior crossbite (P = 0.004). CONCLUSIONS: The prevalence of malocclusion was higher among children with MZV. Late eruption, hypoplastic maxillary arch, hypoplastic mandibular arch, excessive overjet, and posterior crossbite were the most common characteristics for this population.