Evaluation of the average pulp cavity volume of primary second molar and canine for obturation of a single primary tooth A preliminary cone-beam computed tomographic study

Objective: Metapex/Vitapex is one of the most commonly used obturating materials in pediatric dental practice in recent times. It is available in a premixed syringe which poses numerous practical difficulties. This study aimed to calculate the root canal volume of maxillary and mandibular canine and second molar using cone-beam computed tomography (CBCT) to determine the quantity/grams of obturation material to obturate a single tooth (mass = density × volume). Materials and Method: This nonrandomized clinical trial is comprised of two parts. The first part involved calculation of average root canal volume using CBCT which was used to calculate the quantity/grams of obturating material. This predetermined quantity was used to obturate primary mandibular second molars and canines, and the quality of obturation was assessed. Results: Assessment of quality of obturation showed optimum length obturation in 53.33% primary second molars and 66.66% primary canines. Conclusion: It can be inferred that even with the use of exact predetermined quantity/grams of obturating material, optimum quality obturation could be achieved, thus avoiding wastage, preventing cross contamination, and simultaneously offering good clinical results. Hence, this study opens further gateways to device ampules containing predetermined mass of obturating material for a single use for obturation of a single primary tooth.

Effects of operation time of durotomy on acute spinal cord contusion / 西安交通大学学报(医学版)

Objective To study the effects of operation time of durotomy on acute spinal cord contusion. Methods Spinal cord contusion models were established in SD rats at T 9 by NYU-Ⅱ impactor.Durotomy was performed immediately(group C),1 h(group D),6 h(group E)and 12 h(group F)after spinal cord contusion, respectively.Rats in group B did not receive durotomy.Open-field locomotor function was evaluated using the Basso-Beattie-Bresnahan(BBB)locomotor rating scale at days 1,3,7,14,21 and 28 after injury in order to compare damage degree of the spinal cord.The percentage of cavity volume(CV%)and lesion length were calculated by"Imagej"software using serial sections stained by hematoxylin/eosin(HE).Results The BBB score in groups C and D was significantly better than that in group B(P ＜ 0.01);CV% and lesion length were significantly lower than those in group B(P＜0.01).The BBB score was higher in group E than in group B(P＜0.05),but lower than in groups C and D.Similarly,CV% was lower than that in group B(P＜0.05),but higher than that in groups C and D(P＜0.05).No difference was found between groups F and B in the BBB score,CV%or lesion length(P＞0.05).Conclusion Decompressive durotomy improved motor function recovery and reduced the damage of the spinal cord in the setting of a thoracic spinal cord contusion injury in SD rats within 6 h after injury.Durotomy 12 h after injury does not affect function outcomes or spinal cord injury after injury.

Characterization of tympanic cavity volume in newborns using computerized tomography scanning / Caracterización del volumen de la cavidad timpánica en recién nacidos usando tomografía computadorizada

This study reports tympanic cavity (TC) volume in newborns, which was missing in the literature. Ex vivo histology and computerized tomography (CT) scans were performed on temporal bone and data were analyzed in part using software developed in house. CT images with a slice thickness of 0.5 mm were obtained from 5 newborn cadavers and analyzed independently by two expert researchers. The border of the TC was delineated manually and measurement of area of interest was calculated on masked images. Then, the area measurements from all sections were added to estimate the total volume. The agreements between the histological and CT findings were then compared for accuracy, repeatability and reliability. The Dice and Jaccard similarity coefficient measures were used as a statistical validation metric to evaluate the assessor's performance in manual volume segmentation. Good assessor agreement was observed with average Dice values above 0.8 indicating that consistent and reliable volume measurements were feasible. The proposed protocol was shown to be accurate in calculating the TC volume, and thus can be used for computer-assisted presurgical planning or for diagnosing structural alterations in TC.

El objetivo fue determinar el volumen de la cavidad timpánica (CT) en recién nacidos, información no encontrada en la literatura. Se realizaron escaners a través de tomografia computadorizada (TC) y estudios histológicos en el hueso temporal; los datos se analizaron utilizando un software desarrollado en nuestra institución. Se obtuvieron imágenes de secciones de TC, de 0,5 mm de grosor, a partir de 5 cadáveres de recién nacidos, los que fueron analizados de forma independiente por dos investigadores expertos. El margen de los cortes de TC fue delineado manualmente y la medición del área de interés se estimó sobre imágenes ocultas. Después, se añadieron las mediciones de área de todas las secciones para estimar el volumen total. Las concordancias entre el estudio histológico y los hallazgos de la TC se compararon en cuanto a precisión, repetibilidad y confiabilidad. Se utilizaron las medidas de coeficiente de similitud de Jaccard y Dice como métrica de validación estadística para evaluar el desempeño del asesor en la medición manual del volumen. Se observó una buena correlación del evaluador con los valores medios de Dice, por encima de 0,8 indicando que es factible obtener mediciones coherentes y confiables de volumen. El protocolo propuesto ha demostrado ser preciso para calcular el volumen de la CT, y por lo tanto se puede utilizar para la planificación prequirúrgica asistida o para el diagnóstico de alteraciones estructurales en la CT.

Changes in hyoid bone and tongue positions, and oral cavity volume after mandibular setback by sagittal split ramus osteotomy

Nasal cavity volume and nasopharyngeal cavity volume in adults measured by acoustic rhinometry / 临床耳鼻咽喉头颈外科杂志

Objective:To investigate the range of normal value of total nasal cavity volume(NV)and total na-sopharyngeal cavity volume (NPV)of healthy adults. Method: Six hundred and fifty-nine healthy adults andeighty-two adults of chronic rhinitis were measured with acoustic rhinometry. Result:The range of NV was29. 922～37. 481 cm3 and NPV was 29. 369～44. 159 cm3. Comparing healthy adults with adults of chronic rhini-tis,there was a significant difference in NV. Conclusion:Acoustic rhinometry suited for objective assessment ofthe nasal airways in adults. It was demonstrated that these data could provide available information for the studyof nasal physiology and pathophysiology,as well as for the diagnosis and judgement of therapeutic effectiveness ofnasal diseases.

A study of the correlations between the tongue and oral cavity volume in the skeletal mandibular prognathism / 대한치과교정학회지

When mandibular prognathic patients are operated orthognathic surgery which reduce the oral cavity volume, tongue volume should be harmonized with oral cavity volume to be changed because prevent the relapse of malocclusion. To decide the need for tongue resection, the author measured the tongue volume and oral cavity volume with stone model which were taken by impression method and study the difference between the ratio of tongue and oral cavity volume in mandibular prognathic group and normal group. The samples were consisted of four groups, the 40 subjects of the control group, 40 subjects of the experimental group. Each group was subdivided into male and female group respectively. The results were as follows: 1. The tongue volume and oral cavity volume measurements are 20.7cm3, 32.7cm3 in the control group respectively, and 24.9cm3, 42.9cm3 in the experimental group respectively. 2. There is no difference in the ratio of the tongue volume to oral cavity volume in control group and experimental group. 3. Correlation coeffiecients between the tongue volume and oral cavity volume are 0.11, 0.29 in experimental group and control group respectively, and 0.43 in gross total group. 4. The tongue volume of male is larger than female(p<0.05).