Measurement Of Tooth Anatomy Of Immature Mandibular Second Premolars Using Cone-beam Computed Tomography

Object:Revascularization is a biologically and regenerative treatment,providing an alternative approach for immature teeth with necrotic pulp.Since Iwaya et al,firstly reported the revascularization of a clinical case in the early 2000 s,the approach for clinical management of infected immature teeth has developed fastly.Dens evaginatus usually occurs in Asian people and is also referred to as central cusp in premolars.Abnormal central cusp most commonly occurs in the mandibular second premolars,and abnormal central cusp broken is one of the main causes of immature teeth with necrotic pulp.There is a lack of standardization of the apical foramen parameters and dentin wall thickness of the immature permanent teeth at different stages.Therefore,it is necessary for us to establish a reference data for tooth root size in immature mandibular second premolars.The aim of this study was to measure the root anatomy of immature mandibular second premolars at Stage 8 using cone-beam computed tomography(CBCT)and CBCT reconstructed panoramic radiographs.Methods:CBCT images of 100 patients with immature mandibular second premolars at Stage 8 were selected.A panoramic image reconstruction was made from the CBCT volumetric data by using Dolphin imaging software.The root and tooth lengths,dentin thickness,mesiodistal and buccolingual dimension of apical foramen of CBCT and CBCT reconstructed panoramic radiographs were measured and compared.Results: There was no significant differences between the left and the right sides mandibular second premolars,whereas the tooth length,root length and buccolingual dimension of apical foramen of females were significantly different from the males(P<0.001).The CBCT reconstructed panoramic radiographs measurements underestimated the tooth lengths but overestimated the mesiodistal dimension and dentin thickness significantly(P<0.001).Conclusion:The CBCT reconstructed panoramic radiographs do not provide a more reliable measure of root anatomy.The root anatomy of the immature mandibular second premolars at stage 8 would provide reference basis for the pulp revascularization,contribute to diagnosis,planning and outcome of treatment in various dental specialties.