A Mouse Model for Studying the Development of Apical Periodontitis with Age.

Older age is associated with reduced immune function. Our aim was to study how age affects the development of apical periodontitis (AP). AP was induced in two age groups of mice (young vs. adult). Histological samples were stained by Hematoxylin Eosin, Brown and Brenn, and Tartrate-Resistant Acid Phosphatase. In addition, the samples were scanned by Micro-Computerized-Tomography (micro-CT) to evaluate apical constriction and periapical lesion size. Cell density in the periapical region was computationally assessed. Moreover, lesion immune cell populations were characterized by flow cytometry and immunofluorescence. The young group presented more canals with necrotic radicular pulp compared to the adults. There was no difference in bacteria location in the canals between the groups. Apical constriction size was larger in the young mice compared to the adults. The periapical cell density was higher in the young group, while the dominant immune cells in the lesions were neutrophils, which also exhibited the highest young/adult ratio. Immunofluorescence demonstrated neutrophils in the lesion. More osteoclasts were present in the lesions of the young mice, in correlation to the higher volume of bone resorption in this group. Overall, we conclude that the immune reaction to AP stimuli was attenuated in the adult mice compared to the young.

Radiographic outcomes following treatment of intrabony defects by freeze-dried bone allograft combined with enamel matrix derivative: A retrospective study.

OBJECTIVE: The aim of this study was to evaluate the radiographic outcomes following regenerative surgery using enamel matrix derivative (EMD) + freeze-dried bone allograft (FDBA). METHOD AND MATERIALS: In total, 74 two- or three-wall intrabony defects were treated by a combination of EMD+FDBA followed by supportive periodontal therapy (SPT) for a minimum of 2 years. Radiographs were taken at baseline and after the follow-up period. The measurements taken were: baseline defect angle, CEJ to the coronal part of the alveolar bone crest (CEJ-BC), CEJ to the apical part of the intrabony defect (CEJ- BD), the intrabony component of the defect (DL), and the defect angle between the lines CEJ-BC and CEJ-BD. RESULTS: Baseline defect angles were divided into three groups: first group defect angle ≤ 22 degrees; second group 22 degrees to 36 degrees; and third group ≥ 36 degrees. A significant difference in DL following treatment was found in all groups (6.930 mm, 4.202 mm, and 2.073 mm respectively; P < .01). The largest difference in DL was measured for the first group. A positive linear correlation was found between baseline values of the defect angle, CEJ-BD, CEJ-BC, and the later change in DL (P < .01). CONCLUSION: The use of EMD+FDBA results in radiographic bone gain. Narrow defect angle and the depth of the intrabony component have significant positive correlation to radiographic bone gain.