## 3 Results  
All specimens presented various types of pulp responses. Healing patterns are shown in Figures 2 and 3. Histological morphology of specimens was altered in both composition and density of pulp tissues after replantation. Healing of pulp tissues underwent the following patterns: (1) normal pulp with disorganization of odontoblastic layer; (2) internal reparative dentin formation with connective tissue, bone-like, and/or cementum-like tissue; and (3) pulp necrosis.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Grade** & **Description and Degree** \\ \hline
0 & Not observed pulp inflammation or regeneration \\
1 & Less than 25\% observed (<25\%) \\
2 & Less than 50\% observed (<50\%) \\
3 & Less than 75\% observed (<75\%) \\
4 & More than 75\% observed (\(\geq\)75\%) \\ \hline \hline \end{tabular}
\end{table}
Table 1: Histomorphometric criteria used in this study.  
Figure 2: Histologic observations of specimens. (**a**,**c**,**e**) are hematoxylin and eosin (H&E) stains of the experimental group, and (**b**,**d**,**f**) are high-magnification images of the squares in (**a**,**c**,**e**) respectively. (**a**) Pulp necrosis is observed. (**b**) Lymphocytes (arrows) and fibroblasts are observed in pulp proper. (**c**) Formation of calcified tissue in pulp is observed. A severe degree of external root resorption is progressed. (**d**) Extensive amount of bone-like tissue (arrows) is formed in pulp. Presence of blood vessel proliferation is visible. (**e**) Pulp regeneration is shown in pulp proper. (**f**) Disruption of the odontoblastic layer and formation of reparative dentin layer is visible. However, pulp proper is normal. Scale bars = 200 \(\upmu\)m for (**a**,**c**,**e**) and 10 \(\upmu\)m for (**b**,**d**,**f**). AV, alveolar bone; D, dentin; P, pulp proper; HC, hypercemetosis; CT, calcified tissue; RD, reparative dentin; BV, blood vessel.  
The intraclass correlation coefficient (ICC) values indicated acceptable inter-examiner reliability in the histomorphometric analysis (ICC = 0.560-0.975). No significant differences between Group I and II were found in pulp regeneration in replantation after 30 min storage (Table 2). However, Group I showed a significantly lower grade of pulp inflammation compared to Group II (\(p\) < 0.05). Figure 4a-h shows IHC morphologies of samples of two groups. Group I showed lower grade of infiltration of macrophages compared to Group II (Figure 4a,b,e,f). Similar amounts of CD31-positive cells were observed in the two groups (Figure 4c,d,g,h).  
In groups of replantation after a 60 min storage period, a significantly higher grade of pulp regeneration occurred in Group I, and a lower grade of pulp inflammation was observed in Group I (\(p\) < 0.05) (Table 3). Figure 4i-p shows IHC morphologies of samples of two groups. A marked degree of vessel proliferation was observed in Group I, whereas various degrees of infiltration of macrophages were observed in Group II. In addition, the healed pulp tissue in one sample of Group I was closely similar with a normal pulp tissue (Figure 4k,l).  
\begin{table}
\begin{tabular}{c c c c} \hline  & **Group I** & **Group II** & \(p\)**-Value** \\ \hline Pulp regeneration & 2.43 \(\pm\) 0.85 & 2.21 \(\pm\) 1.37 & 0.721 \\ Pulp inflammation & 1.00 \(\pm\) 1.11 & 2.21 \(\pm\) 1.25 & 0.014 * \\ \hline \end{tabular}  
* = statistically significant (\(p\) < 0.05, Mann–Whitney U test).  
\end{table}
Table 2: Histomorphometric analysis of the replantation after 30 min storage. There was no difference in the area of pulp regeneration in Group I and II, but there was a statistically significant difference in the area of pulp inflammation in Group I and II.  
Figure 3: Histologic sections of teeth according to groups. (**a,c**) H&E stains of Group I and (**b,d**) those of Group II. D, dentin; P, pulp proper; CT, calcified tissue; BV, blood vessel; PN, pulp necrosis; black arrow, lymphocyte. Scale bars = 100 \(\upmu\)m.