Histologic, Radiographic, and Micro-Computed Tomography Evaluation of Experimentally Enlarged Root Apices in Dog Teeth with Apical Periodontitis after Regenerative Treatment.

BACKGROUND: Blood clot (BC) and platelet-rich fibrin (PRF) has been successfully used to biologically treat immature roots. It is nowadays considered the treatment of choice. OBJECTIVE: This study aimed to determine the ability of PRF and BC scaffolds to enhance regeneration of disinfected root canals and healing of apical periodontitis within experimentally enlarged canal apices of dog teeth. METHODS: Forty-eight root canals in 28 mandibular premolars from 4 healthy adult dogs were experimentally infected and developed apical periodontitis. The teeth were randomly divided into a control (untreated) group, a disinfection only group, a group that received disinfection and a BC scaffold, and a group that received disinfection and a BC + PRF scaffold. Healing of the apical radiolucency was evaluated by conventional radiography, micro-computed tomography, and histology after 3 months. The data were analyzed by χ2 test. RESULTS: Healing was achieved in 49% of roots as seen on radiograph and 43% as seen on micro-computed tomography. There was no significant between-group difference in the presence or absence of periapical radiolucency in the mesial roots when seen on conventional images (P = 0.255), but there was a significant difference in the distal roots (P = 0.001); similarly, on micro-computed tomography, there was no significant between-group difference in the mesial roots (P = 0.174) but there was a significant difference in the distal roots (P = 0.001). Histologically, apical closure was significantly not greater in the BC + PRF scaffold group than in the BC scaffold group (P = 0.001). CONCLUSIONS: A mix of BC + PRF scaffold did not improve tissue regeneration in experimentally enlarged dog teeth. (Curr Ther Res Clin Exp. 2021; 82:XXX-XXX) © 2021 Elsevier HS Journals, Inc.

Clinical implications of calcifying nanoparticles in dental diseases: a critical review.

BACKGROUND: Unknown cell-culture contaminants were described by Kajander and Ciftçioglu in 1998. These contaminants were called nanobacteria initially and later calcifying nanoparticles (CNPs). Their exact nature is unclear and controversial. CNPs have unique and unusual characteristics, which preclude placing them into any established evolutionary branch of life. AIM: The aim of this systematic review was to assess published data concerning CNPs since 1998 in general and in relation to dental diseases in particular. MATERIALS AND METHODS: The National Library of Medicine (PubMed) and Society of Photographic Instrumentation Engineers (SPIE) electronic and manual searches were conducted. Nanobacteria and calcifying nanoparticles were used as keywords. The search yielded 135 full-length papers. Further screening of the titles and abstracts that followed the review criteria resulted in 43 papers that met the study aim. CONCLUSION: The review showed that the existence of nanobacteria is still controversial. Some investigators have described a possible involvement of CNPs in pulpal and salivary gland calcifications, as well as the possible therapeutic use of CNPs in the treatment of cracked and/or eroded teeth.