Statistical analysis of all tests was completed using unpaired Student’s t test (two-tailed). Statistical significance limit was set at 5% (p < 0.05). Histometrical analysis of the cross-sections in fluorescence microscopy showed that the animals submitted to intermittent administration of PTH (T6) presented a significant increase of 5% in the dentine apposition rate when compared with the control animals (C6) (Table 1). As described in Section 2, this experiment was replicated twice under the same conditions and the histometric findings were similar. Here, we showed only the data of one of two sets of the

experiments conducted for analysis Akt targets of dentine apposition rate (Table 1). In the T6 group, ALP plasma levels were 25% higher than those in the C6 group (Table 1). The results obtained from the knoop microhardness testing, performed on

the mesial face of dentine cross-sectioned incisors, demonstrated that the animals that were treated daily with PTH over 10 days (T10) showed greater microhardness than did the control animals (C10) (11%) (p = 0.0004), as shown in Fig. 3. To evaluate changes in the chemical composition of dentine submitted to PTH treatment, the elemental contents selleck compound of peritubular and intertubular dentine were measured by EDX microanalysis (Table 2). The P (23%) (p = 0.0056) and Ca (53%) (p = 0.0028) at.% content in peritubular dentine was increased in the T10 group, compared with C10 group. The Ca/P ratio in peritubular dentine of T10 animals was also higher than the C10 animals (24%) (p = 0.0011). The chemical composition of intertubular dentine did not differ between the groups. Dentinogenesis is a continuous process of matrix deposition during the life of a tooth. Rodent incisors grow continuously throughout the animal’s life, making them an important model of the dentine HSP90 formation process.13 and 23 In mice, dentine from the incisor region underlying the first molar is rapidly mineralized, and is therefore at

an ideal stage for the measurement of the mineral apposition rate. Both tetracycline and calcein bind to newly formed mineral, which then fluoresces under UV light.24 Although the effects of PTH on dentine formation have been discussed,2, 25, 26 and 27 this study is a first report to investigate the intermittent hPTH 1-34 administration effect on the quality and appositional rate of dentine during incisor formation in healthy young mice. In the present study, it was demonstrated, by measurements using fluorescent markers, that the hPTH 1-34 causes an anabolic effect on dentine deposition during incisor formation in young mice. In addition, short-term PTH administration (T6 group) results in an increase (25%) of the ALP blood levels in relation of C6 group (Table 1). ALP is a marker of bone turnover28 and changes in the release of ALP may indicate an action of PTH intermittent administration.29 Lundgren et al.