ABSTRACT
<p><b>OBJECTIVE</b>To investigate the relationship between the stages of calcification of various teeth and cervical vertebral bone ages among children and adolescents in Chengdu.</p><p><b>METHODS</b>The study subjects consist of 256 children and adolescents in Chengdu with age ranging from 10 to 16 years. All panoramic radiographs and cephalometric radiographs were obtained. The relationship with the stages of chronological ages, calcification of various teeth and cervical vertebral bone ages were analyzed.</p><p><b>RESULTS</b>The Spearman rank correlation coefficient revealed highly significant relationships between cervical vertebral bone ages and chronological ages (r = 0.726, P < 0.01). Dental ages and chronological ages had medium relationship (r = 0.629, P < 0.01), also dental ages and cervical vertebral bone ages medium relationship (r = 0.668, P < 0.01).</p><p><b>CONCLUSION</b>Cervical vertebral bone ages, chronological ages and dental calcification stages have correlation among children and adolescents in Chengdu. The cervical vertebral bone ages have high connection with chronological ages. Cervical vertebral bone age might be a better indicator in judging growth and development of children and adolescents during orthodontic treatment.</p>
Subject(s)
Adolescent , Child , Female , Humans , Male , Age Determination by Skeleton , Cephalometry , Radiography, Panoramic , ToothABSTRACT
<p><b>OBJECTIVE</b>To study the biocompatibility of porous calcium phosphate ceramics nanocomposite.</p><p><b>METHODS</b>The biocompatibility was evaluated via experiments including the hemolysis test, hemopexis test, acute systemic toxicity test, pyrogen test, and intramuscular implant test, in which biphasic calcium phosphate nanocomposite (NanoBCP) presented as leaching solution, suspension or blocks of 5 mmx5 mmxl mm. Animals including New Zealand Rabbits, Kunming mice, SD rats were selected as the host.</p><p><b>RESULTS</b>The hemolysis of NanoBCP was 1.1% (<5%). Four coagulation index levels were within the normal range. In pyrogen test, the temperature of each experimental rat increased by 0.35, 0.40, 0.28 degrees C (<0.60 degrees C, in accordance with the pyrogen-free criterion for biomedical materials). No consequent death, dyspnoea, organ dysfunction, severe peritoneal irritation or ptosis was observed in acute systemic toxic test. Newly-formed fibrous tissue could be found after the implantation.</p><p><b>CONCLUSION</b>The material possesses outstanding biocompatibility and degradability with no toxicity or irritation, contains no pyrogen, as well as better degradation properties than biphasic calcium phosphate.</p>