The purpose of the present study was to develop normative cephalometric standards for Norwegians from 6 to 18 years of age. The subjects in the study included 39 females and 35 males, from the Nittedal growth material. All subjects were Caucasians, and none had undergone orthodontic therapy, all had clinically acceptable normal occlusions and no apparent facial disharmony. Twenty-six measurements were analysed according to the cephalometric analysis used at the University of Oslo Department of Orthodontics. The measurements of posterior facial height, skeletal and soft tissue profiles were also included Comparisons between the dentofacial parameters of females and males at each age were performed using Student's t-test. Significant differences between females and males were present particularly at ages 12 and 15 years of age. There was a significant mean increase in NL/NSL in both sexes from 6 to 15 years of age, but more in females. There was a significant mean decrease in ML/NSL from 6 to 18 years of age, and the angle was significantly smaller in males than in females. The anterior and posterior facial height increased in both sexes from 6 to 18 years of age. The largest increase was in males. Males showed slightly more proclined upper incisors at age 9, 12, and 15 years than females. S-N-A increased more in males than females with the largest increase between 9 and 15 years of age. S-N-B increased in both sexes from 6 to 18 years of age with the largest increase in males.(ABSTRACT TRUNCATED AT 250 WORDS)

The purpose of this study was to evaluate the effect of 0.05% sodium fluoride and 0.12% chlorhexidine mouthwashes on the micro-hardness of tooth enamel and cementum that was exposed to therapeutic doses of gamma radiation. Sixty extracted human teeth were divided into two groups, one was irradiated, the other was not irradiated. The two groups were further subdivided into three subgroups, which were each treated either with 0.05% sodium fluoride or with 0.12% chlorhexidine; the third subgroup served as a control. After demineralization-remineralization cycling, teeth from the irradiated groups showed a significantly lower micro-hardness when compared to those from the non-irradiated groups. Both in the irradiated and non-irradiated groups, teeth from the control subgroups showed a significantly lower micro-hardness, as compared to teeth treated with sodium fluoride and chlorhexidine. For non-irradiated enamel samples, those treated with chlorhexidine showed a significantly less micro-hardness compared to those treated with sodium fluoride. In contrast, irradiated enamel showed no significant difference in micro-hardness, whatever treatment (chlorhexidine or sodium fluoride) was applied. For cementum, treatment with chlorhexidine resulted in a significantly lower micro-hardness compared to sodium fluoride, both for the irradiated and non-irradiated groups. It is concluded that gamma irradiation with therapeutic doses typically used for head and neck carcinoma treatment has a direct effect in reducing micro-hardness of tooth enamel and cementum. Mouthwash protocols including, for example, application of 0.05% sodium fluoride or 0.12% chlorhexidine three times per day for 6 weeks, can protect enamel and cementum against the reduction in hardness and demineralization caused by gamma irradiation. Sodium fluoride offers more protection compared to chlorhexidine.

The purpose of this study was to compare the dentofacial changes in Norwegian and Iowan populations between 6 and 18 years of age. Comparisons of the absolute and incremental changes were made both longitudinally and cross-sectionally. The Norwegian sample consisted of 39 females and 35 males, the Iowa sample consisted of 15 females and 20 males, for whom complete sets of data were available for the period of the study. All subjects had a clinically acceptable occlusion and had not undergone previous orthodontic treatment. Descriptive statistics summarized the changes in 29 parameters. Longitudinal comparison of the growth curves evaluated the curve profiles and curve magnitudes for the two populations for both males and females. The analysis of variance was also used to compare the absolute and incremental changes at ages 6, 9, 12, 15, and 18 years. The study resulted in the following findings: 1. The longitudinal growth profile comparisons of the various dentofacial parameters indicated that the growth trends of the Norwegian and Iowa groups were essentially similar. 2. The comparisons of the growth profiles of the males and females from the two populations also indicated that there were no significant differences between the shape of their growth curves. 3. The comparisons of the curve magnitude, as well as the results of the cross-sectional comparisons, indicated that Norwegians had significantly greater maxillary and mandibular protrusion, and larger proclination of the upper and lower incisors than the Iowans.

Background:The aim of this study was to investigate the antioxidant effect of L-carnitine (LC) against gamma-irradiation-induced oxidative damage in tongue of albino rats after total body irradiation with a single dose of 6 Gy. Materials and Methods: 48 adult rats were randomly divided into 3 groups of 16 animals each. Group I was irradiated with a single dose of 6 Gy. Group II received a daily i.p. injection of LC (250 mg/kg, i.p.) for 5 consecutive days and 1 h after the last dose, rats were irradiated with a single dose (6 Gy). Group III received a daily i.p. injection of LC (250 mg/kg, i.p.) and Vitamin E 40 mg/kg intramuscular daily for 5 consecutive days and 1 h after the last dose, rats were irradiated with a single dose (6 Gy). At day 7 and day 14 after treatment exposure, 8 rats from each group were sacrificed. Results: Administration of LC resulted in attenuation of the histological changes noticed in irradiated rats. The number of p53 positive nuclei significantly decreased in rats receiving LC alone or in combination with VE. Conclusion: LC and VE has shown positive effect in minimizing the epithelial atrophy of tongue mucosa after radiotherapy, which was emphasized by decreasing apoptotic activity in these tissues.

The aim of the study was to examine the impact of Low-level laser therapy (LLLT) on gamma-irradiated teeth regarding tooth structure hardness, salivary pH and salivary IgA. Material and Methods: Thirty adult male albino rats were separated into three groups, which were control group, irradiated group (animals irradiated with a dose of 6 Gy) and gamma irradiated + Laser (the rats wear exposed to low level laser after three days of gamma radiation). Results: The obtained results revealed that the combination group (Gamma + Laser) recorded the highest salivary IgA followed by Control group while Gamma group recorded the lowest salivary IgA. Also, it was found that the Control group recorded the highest salivary pH followed by the combination group while Gamma group recorded the lowest salivary pH. The combination group (Gamma + Laser) recorded the highest tooth hardness followed by Gamma group while the control group recorded the lowest tooth hardness. Conclusion: With the limitations of this study, it was conducted that the Low-level laser therapy post gamma irradiation reflected a significant increase in salivary pH, salivary IgA and tooth hardness compared to both the control and the gamma-irradiated groups.