A non-carious cervical lesion (NCCL) is the loss of hard dental tissue on the neck of the tooth, most frequently located on the vestibular plane. Causal agents are diverse and mutually interrelated.In the present study all vestibular NCCL were observed and recorded by the tooth wear index (TWI). The aim of the study was to determine the prevalence and severity of NCCL. For this purpose, 18 555 teeth from the permanent dentition were examined in a population from the city of Rijeka, Croatia. Subjects were divided into six age groups. The teeth with most NCCL were the lower premolars, which also had the largest percentage of higher index levels, indicating the greater severity of the lesions. The most frequent index level was 1, and the prevalence and severity of the lesions increased with age.

The aim of this study was to evaluate the cytotoxicity of the root canal sealers RoekoSeal Automix (RSA) and AH Plus in vitro on human cervical carcinoma (HeLa) cells and mouse skin fibroblasts (L929). The sealers were covered with a 3 x 10(4) cell suspension 1 h, 24 h, 48 h, 7 days and 1 month after mixing. Four samples and respective controls without sealer were prepared. After 5 days of incubation, the number of cells was determined using an electronic counter; the number of viable cells was determined under light microscopy following the addition of nigrosin dye. The experiment was repeated twice for each sealer and each period. AH Plus was significantly more cytotoxic after 1 h, 24 h, and 48 h, compared to the 7 day and 1 month setting period on both cell lines. RoekoSeal had no cytotoxic effect on either cell line at any setting time.

The aim of this study was to develop a three-dimensional (3D) finite element model (FEM) of the first maxillary premolar in order to compare the stress profiles in the buccal and palatal cervical regions. The 3D geometry of the tooth was reconstructed, the solid model was transferred into a finite element program where a 3D mesh was created, and the stress distribution analysis was performed. Two typical cases have been considered: the tooth under normal occlusion (case I) and the tooth under malocclusion (case II). In case I, larger compressive stresses were found in the cervical enamel and dentine. Tensile stresses were found in the fissure system, adjacent area, and at the vestibular surface of the buccal cusp. The peak values for the principal stress ranged from -259 to +2.25 MPa in the cervical areas. In the case II, larger compressive stresses were found in the palato-cervical enamel and dentine. Tensile stresses were found inside the enamel in the fissure system, adjacent area, at the vestibular surface of the buccal cusp, and in the bucco-cervical enamel. The peak values for the principal stress ranged from -501.947 MPa in palatal region to +82.4 MPa in the buccal region This study implies a role of occlusal forces in development of non-carious lesions. In the case of malocclusion, tensile stresses generated on the cervical areas were higher compared with the stresses generated in the case of normal occlusion and it is probably capable of producing non-carious cervical lesion.

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Aim. The aim of this study was to evaluate the presence of the cytokines tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in human periapical lesions. Subjects and methods. Samples were obtained from three groups of teeth: symptomatic teeth, asymptomatic lesions, and uninflamed periradicular tissues as a control. Results. TNF-alpha levels were significantly increased in symptomatic lesions compared to control. Group with asymptomatic lesions had significantly higher concentrations compared to control. There were no significant differences in TNF-alpha levels between symptomatic and asymptomatic lesions. In group with symptomatic lesions, IL-6 levels were significantly higher than in group with asymptomatic lesions. The IL-6 levels in symptomatic group also showed significantly higher concentration in comparison with control group. In asymptomatic group, the IL-6 level had significantly higher concentrations compared to control. Conclusion. These results indicate that symptomatic lesions represent an immunologically active stage of disease, and asymptomatic lesions are the point from which the process advances toward healing.

Severe xerostomia is a common late radiation consequence, which occurs after irradiation of head and neck malignancies. The aim of the present study was to analyze apoptosis and proliferation and their relationship during the late post-irradiation phase. C57BL/6 mice were locally irradiated in head and neck region with a single dose of 7.5 or 15 Gy and their submandibular glands were collected at 40 and 90 days after irradiation. To identify apoptotic cells, the TUNEL method was employed and immunohistochemistry with proliferating cell nuclear antigen (PCNA) was used for detecting proliferation. Histological changes at day 40 were mild in contrast to day 90 when glands of irradiated mice showed severe atrophy, vacuolization and mononuclear infiltration. Acinar cells, granular and intercalated duct cells of mice irradiated with 7.5 and 15 Gy expressed higher apoptotic index than cells of non-irradiated, control glands at both examined time points. At 40 days, a higher proliferation index in granular and intercalated duct cells was detected only in group irradiated with 7.5 Gy. At 90 days, proliferation index for all cell types in both irradiated groups was similar to the controls. According to our results, the imbalance between apoptosis and proliferation caused by X-irradiation may be the reason for gland impairment during the late post-irradiation phase.

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