Uncommon dentigerous cyst related to a maxillary lateral incisor in a 03-year-old boy

Background

The dentigerous cyst is usually defined as a cystic cavity that surrounds the crown of an unerupted tooth on the cementoenamel junction. The present article reports a case of an uncommon dentigerous cyst, highlighting its clinical, radiographic and surgical characteristics and discussing the aspects related to its development in infancy.

Case report

A 03-year-old boy patient presented with an extensive radiolucid area involving the crown of the right maxillary lateral incisor. A surgical excision was performed. Anatomopathological examination revealed a cystic tissue with a fibrous wall surrounded by nonkeratinized stratified squamous oral epithelium, without atypia.

Conclusion

It is possible that the dentigerous cyst grows in the dental germ in any stage of development and not only in the follicle of a tooth with calcified crown attached to the cementoenamel junction.     

DNA repair gene expression in biological tissues exposed to low-intensity infrared laser

Special properties of laser light have led to its usefulness in many applications in therapy. Excitation of endogenous chromophores in biotissues and generation of free radicals could be involved in its biological effects. DNA lesions induced by free radicals are repaired by base excision repair pathway. In this work, we evaluated the expression of APE1 and OGG1 genes related to repair of DNA lesions induced by free radicals. Skin and muscle tissues of Wistar rats were exposed to low-intensity infrared laser at different fluences and frequencies. After laser exposition of 1 and 24 h, tissue samples were withdrawn for total RNA extraction, cDNA synthesis, and evaluation of APE1 and OGG1 gene expression by quantitative polymerase chain reaction. Data obtained show that laser radiation alters the expression of APE1 and OGG1 mRNA differently in skin and muscle tissues of Wistar rats depending of the fluence, frequency, and time after exposure. Our study suggests that low-intensity infrared laser affects expression of genes involved in repair of DNA lesions by base excision repair pathway.     

S-nitrosoglutathione decreases inflammation and bone resorption in experimental periodontitis in rats

Background: S‐nitrosoglutathione (GSNO) is a nitric oxide donor that may exert antioxidant, anti‐inflammatory, and microbicidal actions and is thus a potential drug for the topical treatment of periodontitis. In this study, the effect of intragingival injections of GSNO‐containing polyvinylpyrrolidone (PVP) formulations is evaluated in a rat model of periodontitis. Methods: Periodontal disease was induced by placing a sterilized nylon (000) thread ligature around the cervix of the second left upper molar of the animals, which received intragingival injections of PVP; saline; or PVP/GSNO solutions which corresponded to GSNO doses of 25, 100, and 500 nmol; 1 hour before periodontitis induction, and thereafter, daily for 11 days. Results: PVP/GSNO formulations at doses of 25 and/or 100, but not 500 nmol caused significant inhibition of alveolar bone loss, increase of bone alkaline phosphatase, decrease of myeloperoxidase activity, as well as significant reduction of inflammatory and oxidative stress markers when compared to saline and PVP groups. These effects were also associated with a decrease of matrix metalloproteinases 1 and 8, inducible nitric oxide synthase, and nuclear factor‐κB immunostaining in the periodontium. Conclusion: Local intragingival injections of GSNO reduces inflammation and bone loss in experimental periodontal disease.     

Treatment times of Class II malocclusion: four premolar and non-extraction protocols

The purpose of this study was to retrospectively compare the treatment times of Class II division 1 malocclusion subjects treated with four first premolar extractions or a non-extraction protocol and fixed edgewise appliances. Eighty-four patients were selected and divided into two groups. Group 1, treated with four first premolar extractions, consisted of 48 patients (27 males and 21 females) with a mean age of 13.03 years and group 2, treated without extractions, consisted of 36 patients (18 males and 18 females) with a mean age of 13.13 years. Group 2 was subdivided into two subgroups, 2A consisting of 16 patients treated in one phase and 2B consisting of 20 patients treated in two phases. The initial and final Treatment Priority Index (TPI), initial ages, initial mandibular crowding, and treatment times of groups 1 and 2 were compared with t-tests. These variables were also compared between group 1 and the subgroups with analysis of variance followed by Tukey's tests. The treatment times for groups 1 and 2 and subgroups 2A and 2B were 2.36, 2.47, 2.25, and 2.64 years, respectively, which were not significantly different. Treatment times with non-extraction and four premolar extraction protocols are similar.