Radix entomolaris: reporte de caso / Radix entomolaris: report of a case

Una de las variaciones anatómicas que pueden presentar los molares inferiores es una tercera raíz que ha sido denominada radix entomolaris o paramolaris dependiendo de su localización, ya sea lingual o vestibular respectivamente. Conocer las variaciones morfológicas de las piezas dentarias es un requisito fundamental para el éxito del tratamiento endodóntico. El objetivo de este artículo es la presentación de un caso clínico de una paciente con ambos primeros molares inferiores con presencia de radix entomolaris; en la pieza dentaria 4.6 se realizó tratamiento endodóntico y en 3.6 con una lesión endoperiodontal combinada verdadera se decidió su exodoncia (AU)

Establishment of first mandibular molar development of the time sequence in ICR mice / 中国比较医学杂志

Objective This study aims to understand the characteristics of the time sequence of ICR mouse first mandibular molar tooth germ development through dynamic observation.Methods Tooth germ of Embryos (E11.5,E12.5,E13.5,E14.5,E15.5,E16.5,E17.5 and E18.5) and postnatal (PN1,PN2) mice were obtained.The heads (E11.5-E15.5) and mandibles (E16.5-PN2) of mice were dissected,fixed and embedded for serial sections and HE staining.All the results were assessed under light microscopy.Results The tooth germ underwent various development stages including the bud,cap and bell stages.Mouse odontogenesis was initiated at E11.5.Proliferation of oral epithelium formed the bud stage at E13.5.Then the cap stage was observed at E14.5-E15.5 and the bell stage was appeared beginning from E16.5.The pre-dentin was observed at PN1,as well as the dentin at PN2.Conclusions Establishing the regular development pattern of the first mandibular molar of ICR mice will provide a reliable basis for the future use in the specific tooth germ developmental research.

A study on the reason of extraction, length, number and transverse morphology of the root and root canals of 100 extracted first permanent mandibular molars / 实用口腔医学杂志

To investigate the reason of extraction, length, number and transverse morphology of the root and root canals of first permanent mandibular molars. 100 extracted first permanent mandibular molars were collected. The length of mesial and distal root of the first permanent mandibular molars was 13.00 mm and 13.51 mm separately. 75% double roots and 25% three roots were observed under the stereomicroscope. Difference of root number and shape of transverse morphology in mesial root were more obvious than those in distal roots of the same first mandibular molars in this study.

Construction of three-dimensional finite element models of the first mandibular molar restored with three post and core systems / 实用口腔医学杂志

Objective:To establish three-dimensional(3D) finite element models of the first mandibular molar restored with three post and core systems.Methods:Three 3D finite element models of the restored first mandibular molars were constructed by using CT image reconstruction technique.Then MIMICS software was used to separate the areas and to finish 3D calculation.GEOMAGIC software was applied to modify and generate a NURBS surface in each patch.All components of the models were assembled under the ANSYS preprocessor.Specific materials parameters were selected to simulate the various restoration and dentin status.Results:The 3D finite element models of restored first mandible molars were successfully established,which were consistent to the situation observed in the clinical environment.Conclusion:It is a practical and accurate method to establish three-dimensional finite element models by CT image reconstruction technique and reverse engineering software MIMICS and GEOMAGIC.

A study on the reason of extraction,length,number and transverse morphology of the root and root canals of 100 extracted first permanent mandibular molars / 实用口腔医学杂志

To investigate the reason of extraction,length,number and transverse morphology of the root and root canals of first permanent mandibular molars.100 extracted first permanent mandibular molars were collected.The length of mesial and distal root of the first permanent mandibular molars was 13.00 mm and 13.51 mm separately.75% double roots and 25% three roots were observed under the stereomicroscope.Difference of root number and shape of transverse morphology in mesial root were more obvious than those in distal roots of the same first mandibular molars in this study.