Circular RNA-Mediated Regulation of Oral Tissue-Derived Stem Cell Differentiation: Implications for Oral Medicine and Orthodontic Applications.

Circular RNAs (circRNAs) are a novel class of endogenous non-coding RNAs (ncRNAs) which unlike linear RNAs, have a covalently closed continuous loop structure. circRNAs are found abundantly in human cells and their biology is complex. They feature unique expression to different types of cells, tissues, and developmental stages. To the present, the functional roles of circular RNAs are not fully understood. They reportedly act as microRNA (miRNA) sponges, therefore having key regulatory functions in diverse physiological and pathological processes. As for dentistry field, lines of evidence indicate that circRNAs play vital roles in the odontogenic and osteogenic differentiation of dental pulp stem cells (DPSCs) and periodontal ligament stem cells (PDLSCs). Abnormal expression of circRNAs have been found in other areas of pathology frequently reflected also in the oral environment, such as inflammation or bone and soft tissue loss. Therefore, circRNAs could be of significant importance in various fields in dentistry, especially in bone and soft tissue engineering and regeneration. Understanding the molecular mechanisms occurring during the regulation of oral biological and tissue remodeling processes could augment the discovery of novel diagnostic biomarkers and therapeutic strategies that will improve orthodontic and other oral therapeutic protocols.

An Orthodontic Approach for Garre's Sclerosing Osteomyelitis of the Mandible.

The nonsuppurative osteomyelitis of the mandible is a rare condition that can occur in children due to low-grade inflammatory processes, dental cavities, periodontal lesions as well as the eruption process of the teeth. We submit a case report involving the orthodontic management of a 9-year-old female patient who presented in our service in the mixed dentition period with diagnosed Garre's sclerosing osteomyelitis of the entire mandibular body. After a full work-up, the following symptoms and signs were noted: bilateral temporomandibular joint (TMJ) pain, loss of the leeway space, anterior open bite, distalization of the secondary maxillary right canine, nail biting and tongue thrust. Our orthodontic objectives were to relieve the TMJ pain, limit the eruption process of the teeth and to diminish the evolution of the osteomyelitis, reduce the growth of the inferior lower third of the face and to prevent further invasive treatment of the patient. In the first phase of treatment, we established a centric relationship using an orthopedic appliance (occlusal splint) and physiotherapy to deprogram the muscles and the TMJ. Throughout the second phase of treatment, we used orthopedic appliances to inhibit the overeruption of the secondary molars. After another year of treatment, the osteomyelitis lesions were under control with the permanent teeth in final position, good facial esthetic and as a functional result, no root resorption. We can conclude that by using low physiological forces to direct and control the growth pattern, good results could be obtained in stabilizing and controlling the sclerosing osteomyelitis of the mandible.