The objective was to determine the prevalence of vital teeth requiring non-surgical root canal therapy (NSRCT) that present with radiolucencies in mature permanent teeth in a pediatric population. A retrospective electronic dental chart review of children treated with NSRCT at VCU’s School of Dentistry between November 30, 2009 and March 1, 2013 was conducted. The presence or absence of a periapical radiolucency was determined from digital radiographs by three calibrated dentists. Specific characteristics of each tooth were collected. Statistical analysis using logistic regression was completed on all teeth with radiolucencies and vital teeth with radiolucencies. NSRCT was completed on 551 teeth. Radiolucencies were present in 246 teeth. Vitality data on access was only available in 184 teeth. In these, the prevalence of vital teeth with radiolucencies was 45.1% (n=83). Significant differences were noted for tooth type, gender, and puberty. Post-pubertal subjects had more vital teeth with radiolucencies than pubertal subjects.

The purpose of this study was to assess the changes in size of periapical lesions 3-12 months following root canal treatment using CBCT. Patients who had non-surgical root canal therapy (NSRCT) or non-surgical retreatment (ReTx) from July 30,2014 to August 19, 2015 with a periapical lesion of endodontic origin and received NSRCT or ReTx and had a pre-treatment or intra-treatment CBCT were invited to participate. Volumetric and linear measurements of periapical lesions on initial and post- treatment CBCT images were performed. A total of 20 patients with 23 treated teeth with 30 separate periapical radiolucent lesions returned for follow up 91-390 days after the initiation of endodontic treatment. Lesions showed an overall reduction in volume (p=0.0096), maximum coronal diameter (p=0.0117), maximum sagittal diameter (p=0.0071), and maximum axial diameter (p=0.0006). Lesions show a significant reduction in size 3-12 months following non-surgical endodontic treatment using CBCT.

Les ostéoclastes, les seules cellules capables de résorber l’os, sont soupçonnés d’être associés au développement et à la progression des radiotransparences sous-chondrales (SR). Ils n’ont par contre jamais été étudiés in situ. Les objectifs de cette étude cadavérique ex vivo étaient de mesurer et de comparer la densité ostéoclastique et le pourcentage de chondroclastes se trouvant à différentes profondeurs de l’os sous-chondral à partir de la surface articulaire dans le condyle fémoral médial (CFM) de chevaux Pur-sang juvéniles sains et atteints de SR hâtives spontanées. Les spécimens provenaient d’une banque de tissus et faisaient partie d’une étude précédente sur les caractéristiques structurelles des SR. La tomodensitométrie identifiait les CFM atteints de SR (n=6) et guidait les coupes ostéochondrales. Les contrôles de l’étude étaient composés d’un site histologiquement normal et caudal à la lésion (n=6) et du site controlatéral à la lésion dans le CFM sain (n=5). Après la décalcification et la fixation dans la paraffine, les spécimens étaient colorés à l’immunohistochimie afin de mettre en évidence les ostéoclastes présents dans l’os en périphérie des SR. Les spécimens étaient ensuite séparés en régions d’intérêt (ROI) à différentes profondeurs de l’os sous-chondral: ROI1 (0-1mm), ROI2 (1-3mm) et ROI3 (3-6mm). Les ostéoclastes ont été comptés dans chaque ROI pour calculer leur densité ostéoclastique respective. Les lames ont été contre-colorées avec la Safranine afin d’identifier le cartilage et mesurer le pourcentage de chondroclastes. La densité ostéoclastique était statistiquement plus élevée dans la ROI1 comparativement à la ROI3 dans tous les groupes. Cependant, aucune différence significative n’a été détectée en comparant les ROI entre les groupes, même si la densité ostéoclastique était supérieure dans la ROI1 des SR. Malgré une proportion de chondroclastes dans la ROI1 des SR inférieure à celle des contrôles, aucune différence significative n’a été détectée. La limite principale de cette étude se révéla être la taille de l’échantillon. Nos résultats démontrent cependant que la pathophysiologie des SR n’est pas uniquement expliquée par l’augmentation du nombre d’ostéoclastes dans l’os sous-chondral en périphérie des lésions. / There is a knowledge gap concerning how and when equine medial femoral condyle (MFC) subchondral radiolucencies (SR) arise and evolve. Osteoclasts, the only cells capable of bone resorption, are believed to have a role, but have not been studied in situ. The objectives of this ex vivo cadaveric study were to measure and compare the osteoclast density and the percentage of chondroclasts in juvenile (<1 year) Thoroughbred MFCs at varying depths from the weightbearing articular surface in both healthy and early spontaneous MFC SR specimens. The MFCs were available in a tissue bank and were part of a prior study of the structural characteristics of SRs. Computed tomography permitted identification of MFC SR (n=6) and guided osteochondral slab sections. Controls included a histologically normal site caudal to the lesions (n=6) and the healthy contralateral MFC lesion site (n=5). Following decalcification, paraffin embedding sections were cut and stained immunohistochemically with Cathepsin K to permit osteoclast identification and counting. The sections were divided into regions of interest (ROI) at different depths in the subchondral bone from the osteochondral junction: ROI1 (0-1mm), ROI2 (1-3mm) and ROI3 (3-6mm). Osteoclasts were counted in each ROI in order to calculate an osteoclast density. A Safranin-O counterstain was performed to identify the cartilage and measure the chondroclasts percentage. Osteoclast density was significantly higher in ROI1 when compared with ROI3 in all groups. When ROIs were compared between the three groups, no statistically significant differences were detected, even if a visible pattern difference and higher osteoclast density values were recorded in ROI1 in SRs. However, although the proportion of chondroclasts in ROI1 was lower in the SR sections when compared with controls, no significant difference was detected. The main limitation was the limited sample size. Osteoclasts are important actors in MFC subchondral bone development, digesting both growth cartilage (chondroclasts) and bone, but the pathophysiology of early MFC SRs cannot be explained solely by an increased osteoclast presence in the peripheral subchondral bone.