Dentoalveolar trauma is considered an emergency condition and is challenging for every dentist. As primary and permanent teeth may suffer repercussions from an injury, a therapist must be mindful of which situations the use of splinting methods is required. In dentistry, a splint is a rigid or flexible device with the function of supporting, protecting, and immobilizing teeth that have been weakened (endodon-tically, periodontally), traumatically injured, replanted, or fractured. Generally, splinting is not recommended for primary teeth injuries such as luxation and avulsion. In permanent dentition, splint appliances are indicated for periodontal injuries, such as subluxation, luxation and avulsion, and hard tissue injuries such as class IV root fractures. Nowadays, there are many appliances that may be used for immobilization of traumatized teeth. Since this issue may sometimes be confusing for dental practitioners, this chapter deals with splint classification (rigid and flexible), the basic characteristics of splints, the indications, and methods of application.

The odontogenic keratocyst (OKC) may occur at any age. However, it mostly occurs during the second and third decades of life. Compared to other odontogenic cysts, this type occurs with a frequency of 5‐15%. It is more common in the mandible region and in the male sex. Histologically, odontogenic keratocysts are characterized by the presence of an external connective tissue capsule, with keratinizing lining of the epithelium consisting of 5‐8 cell layers with marked palisadisation of polarized basal cells and a corrugated parakeratin layer. The objective of this study is to present cases of odontogenic keratocysts, with reference to the latest classification and dilemmas in therapeutic doctrine. This project was realized in the form of descriptive studies, specifically in a series of cases. A collection of four individual cases was found at the Department of Oral Surgery. Due to the proper approach towards diagnosis, adequate and detailed histopathological analysis, and suitable therapeutic procedures, all cases of odontogenic keratocysts were successfully treated without complications. Enucleation of OKC, with a regular follow‐up, proved to be the effective therapeutic choice for the patients described in this paper. Only in the case of recurrence would we consider other therapeutic options, primarily enucleation in combination with Carnoy’s solution.

OBJECTIVES In silico bioinformatical analysis suggested that the expression of two genes, CCL5 (C-C Motif Chemokine Receptor 5) and ep300 (Histone acetyltransferase p300), could be used as potential new biomarkers in differentiation between periapical granulomas and radicular cysts. Thus, we hypothesized that gene expression of CCL5 and ep300 in periapical lesions would classify the lesions as either granuloma or cyst. MATERIALS Patient samples (n=122) included 46 periapical granulomas, 38 radicular cysts and 38 healthy gingival samples as controls. Real-time PCR analysis of CCL5 and ep300 transcripts was compared to SDHA (Succinate dehydrogenase complex, subunit A) as the reference. Clinical parameters (e.g., intensity of inflammation and lesion size) were measured and correlated with CCL5 and ep300 expression. ROC (Receiver operating characteristic) and logistic regression analyses were used to establish the diagnostic character of ΔCt values. RESULTS Granulomas and radicular cysts had significantly higher expression of CCL5 and ep300 compared to controls (P<0.05). However, no differences were observed when comparing granulomas and radicular cysts. ROC analyses showed that CCL5 and ep300 have good diagnostic accuracy, but low accuracy for distinguishing between the lesions. CONCLUSIONS This study confirmed that expression of CCL5 and ep300 is relevant for the pathogenesis of periapical inflammatory lesions but cannot be used as a distinctive marker between these lesions.

Odontogenic cysts are a group of common pathological lesions of the jaw. Typically, they can be found randomly on X-rays as round benign lesions. However, some of them can behave aggressively with a tendency toward malig-nancy. Among odontogenic cysts with benign pathology, up to 60% of all jaw cysts are radicular cysts, which originate from root canal infection. Pathogenesis involves the interaction between osteoblasts, osteocytes, and osteoclasts as well as the expression of RANK-RANKL/OPG signaling system. Furthermore, collagenases (e.g., MMPs) are expressed in epithelial lining of the cyst. Among odontogenic cysts with potentially aggressive behavior, odontogenic keratocysts (OKCs) have a high rate of recurrence and very debatable treatment options; they can be associated with Gorlin syndrome. Keratocysts have developmental origin and show variability in their gene expression profiles. Their etiology is closely related to genetic factors, especially mutations in different members of Shh signaling pathway, including PTCH gene. cells proliferate, the epithelial nest is formed. When the epithelial nest reaches the size of 1 cm, the center becomes necrotic leading to the formation of future cystic cavity, which becomes lined with the epithelium. For unknown reasons, this epithelium starts secreting fluid, which is called cystic fluid. These steps lead to the formation of radicular cyst, a round cavity filled with fluid and lined with the epithelium and fibrous connective tissue. This description of the radicular cyst development is the prevailing theory.

BACKGROUND/AIMS The best treatment for an avulsed tooth is immediate replantation. If this is not possible, a proper transport medium is required for the maintenance of viability of the periodontal ligament cells (PDL). The aim was to systematically review the efficacy of different storage media used for the survival of PDL cells of avulsed teeth in the in vitro setting. METHODS The search strategy was based on the MeSH keywords in PubMed/MEDLINE: "Transport media for avulsed teeth," "Storage media for avulsed teeth," "Knocked out teeth," "Tooth avulsion," "Biological transport of avulsed tooth," "Cell survival of avulsed tooth," "Cell viability of avulsed tooth," "Tooth replantation," and "Periodontal ligament in avulsed teeth." The "AND" and "OR" Boolean operators were applied to combine keywords. Each study was evaluated for eight criteria, including use of human PDL, in vitro cell culture models, the number of passages, types of storage media, percentages of surviving PDL cells, pH and osmolality of storage media, and the type of test used to asses PDL viability. RESULTS In 15 selected studies, nine storage media (HBSS, tap water, DMEM, milk, saliva, 10% and 20% propolis, Gatorade, and Viaspan) were analyzed at six time points. For storage up to 2 hours, HBSS, DMEM, milk, 10% propolis, 20% propolis, and Viaspan conserved more than 80% of PDL viability. For storage at 24 hours, Viaspan showed best cell survival at 88.4%, followed by DMEM (70.9%) and 10% propolis (68.3%). Milk and HBSS showed similar PDL survival at 24 hours (57.2% and 57.3%, respectively). CONCLUSIONS Milk remains the most convenient, cheapest, and readily available solution in most situations while also being capable of keeping PDL cells alive. Further studies are required to evaluate the efficacy of more commonly found storage media besides milk.