Dental Pulp

The purpose of this study was to evaluate the influence of coronal leakage on the healing of dogs' periapical tissues after root canal filling, post space preparation and protection or not with a temporary sealer plug. Forty root canals of dogs' teeth were instrumented and filled by the lateral condensation technique with gutta-percha points and Endomethasone or CRCS sealers. After post space preparation, the remaining filling material was protected or not with a plug of temporary Coltosol sealer and exposed to the oral environment for 90 days. Thereafter, the animals were sacrificed and the specimens were removed and prepared for histomorphological and histobacteriological analysis. The findings revealed 35% of microbial leakage in the groups without plugs and 15% of leakage in the groups with plugs. Statistical analysis showed that the use of a Coltosol plug improved significantly the histomorphological results regardless of the type of root canal sealer (p=0.05) and that CRCS and Endomethasone sealers showed similar results (p>0.05).

ABSTRACT: Estimation of age in individuals has received considerable attention in forensic science, in which it is a widely used method for individual identification, together with paleo-demographic analyses to establish mortality patterns in past populations. The present investigation, which is a continuation of a previously published pilot study, was conducted to examine the possible application of the pulp/tooth area ratio by peri-apical images as an indicator of age at death. A total of 200 peri-apical X-rays of upper and lower canines were assembled from 57 male and 43 female skeletons of Caucasian origin, aged between 20 and 79 years. They belong to the Frassetto osteological collection of Sassari (Sardinia) and are housed in the Museum of Anthropology, Department of Experimental and Evolutionistic Biology, University of Bologna. For each skeleton, dental maturity was evaluated by measuring the pulp/tooth area ratio on upper (x1) and lower (x2) canines. Very good agreement was found between intraobserver measurements. Statistical analysis was performed in order to obtain multiple regression formulae for dental age calculation, with chronological age as dependent variable, and gender, and upper and lower canines as independent variables. Stepwise regression analysis showed that gender did not contribute significantly to the fit (p=0.881) whereas variables x1 and x2 and the first-order interaction between them did. These two variables explained 92.5% of variations in estimated chronological age and the residual standard error was 4.06 years. Lastly, two simple linear regression equations were obtained for age estimation using canines from the maxilla and mandible separately. Both models explained 86% of variations in estimated chronological age and allowed an age-at-death estimate with a residual standard error of about 5.4 years.

The aim of this study was to evaluate, in vitro, with scanning electron microscope (SEM), the appearance of root canal walls shaped by three different rotary NiTi techniques and one conventional manual technique in human extracted teeth. Four different instruments were used: K3, Hero 642, RaCe and K-file. Each sample was irrigated with 5 ml of 5% NaOCl and 5 ml of 3% H2O2 and EDTA, Rc-Prep (1 ml). Each sample was prepared for SEM observation and analyzed in the coronal, middle and apical third, comparing its aspect with a predefined scale of four different parameters: presence of smear layer, pulpal debris, inorganic debris and surface profile. The apical third showed significantly more pulpal and inorganic debris, smear layer and a high number of surface profile irregularities. No significant difference was found at the coronal, middle and apical thirds between manual and rotary techniques for inorganic debris, smear layer and surface profile. Much pulpal debris were found in the apical third for K3 and RaCe compared with Hero 642 and K-file. In conclusion, mechanical rotary techniques with NiTi instruments produced quite similar results compared with a conventional manual technique using K-files. The present study demonstrated that dentin and pulpal debris, the morphology of smear layer and surface profile were only partially influenced by the type of endodontic instruments. The apical third was the anatomical area with greater amount of debris and smear layer.

summary  The purpose of this study was to evaluate the effect of simulated intrapulpal pressure on the shear bond strength (SBS) of a self-etching bonding system (Clearfil Liner Bond II) to both enamel and dentine surfaces. Forty-two caries-free human molar teeth were randomly assigned to two equal groups (n=21). One group of 21 teeth was connected to a special pulpal pressure machine, which is developed to simulate in vivo conditions. The buccal and lingual surfaces of the teeth were prepared with a diamond wheel to create flat dentine and enamel surfaces. A self-etching bonding system was then applied under pulpal pressure and 2·5 mm diameter composite cylinders were bonded to the prepared surfaces. The samples were then stored in distilled water at room temperature for 24 h under pulpal pressure before SBS was tested. The second restored group was used as a control and the teeth were not connected to the pulpal pressure apparatus during material application and test procedures. They were stored for 24 h in distilled water at room temperature before the SBS test. Fracture analysis of the enamel and dentinal surfaces was performed using a stereomicroscope. Shear bond strength values to dentine was significantly reduced with pulpal pressure (P < 0·001). However, in the enamel, SBS was increased (P < 0·001). In the control group, the SBS values to dentine and enamel did not show any significant difference (P > 0·05). Based on these results, it can be concluded that further analysis of enamel histology and bonding mechanisms are needed.

The mechanisms of odontogenic pain are complex and incompletely understood. Cases of irreversible pulpitis are thought to represent a localized inflammatory response to bacterial challenge in dental pulp tissue. The presenting symptoms are classically defined by exaggerated painful episodes to thermal stimuli that may linger after cessation of the stimulus. However, the associated incidence of mechanical allodynia, defined as reduced mechanical pain threshold to masticatory forces, has not been characterized. This study evaluated pain intensity ratings and the presence of mechanical allodynia reported by 993 consecutive dental patients presenting for tooth extraction in a community health center. After clinical and radiographic examinations, the pulpal/periradicular diagnostic categories were normal pulp/normal periradicular (n = 792 patients), irreversible pulpitis/normal periradicular (n = 86), or irreversible pulpitis/acute periradicular periodontitis (n = 115). The rank order for the mean values of pain intensity ratings was irreversible pulpitis/acute periradicular periodontitis > irreversible pulpitis/normal periradicular > normal/normal (p < 0.05 for all comparisons). The incidence of mechanical allodynia in patients presenting with irreversible pulpitis was 57.2%, indicating that periradicular mechanical allodynia contributes to early stages of odontogenic pain because of inflammation of vital pulpal tissue.

This study conducted an in vitro analysis of the level of apical transportation in mesiobuccal roots of upper molars after manual instrumentation with stainless steel files, preparation with the K3 system, and with a reciprocating NSK handpiece. Sixty roots were mounted in muffles and then longitudinally sectioned. A digital image was acquired of the inner surface of one root half. After instrumentation, the inner surfaces of the same root halves were digitized with file sizes #30, #35, and #40. Each image obtained was superimposed over the corresponding preoperative image, and the apical transportation was measured. The Friedman and Wilcoxon tests were used to compare results for the file sizes, and comparison of the groups was made with the Kruskal-Wallis test, demonstrating statistically significant differences (P = .000). The stainless steel file sizes #35 and #40 caused significant apical transportation, and K3 system proved safe for apical preparation, with little deviation.

In this study we wanted to identify the effect of enamel matrix derivative (EMD) on adipocytokines, so-called adipokines. Primary human cells of mesenchymal origin (osteoblasts, periodontal ligament cells, mesenchymal stem cells, and pulp cells) and hematopoietic origin (monocytes) were incubated with EMD. The levels of adipokines in cell culture medium were quantified using the Lincoplex human adipocyte panel (Luminex) and by real-time PCR of mRNA isolated from cell lysates. Rats were injected with 2 mg of EMD or saline intramuscularly every third day for 14 d. Blood samples were taken before and after injections, and the level of resistin in rat plasma was measured by ELISA. We found a dramatic increase in the secretion of resistin from mesenchymal stem cells, and verified this result in all the cells of mesenchymal origin tested. However, we observed no significant changes in the amount of resistin secreted from monocytes exposed to EMD compared with the control. Injections of EMD significantly enhanced the circulating levels of resistin in rats, and EMD also significantly enhanced the activity of the resistin promoter in transfected mesenchymal stem cells, indicating a direct effect on resistin expression. Our results indicate that resistin may play a role in mediating the biological effect of EMD in mesenchymal tissues.

Hydration and ionic composition of the subretinal space (SRS) is modulated by the retinal pigment epithelium (RPE). In particular calcium concentration (Ca(2+)) in the SRS varies with light exposure, and although this change is regulated by RPE transport activity, the specific transport proteins involved have yet to be defined. Two members of the transient receptor potential vanilloid family, TRPV5 and TRPV6, are calcium selective ion channels and are known to be expressed in calcium-transporting epithelial tissues. The present work characterizes of TRPV5 and TRPV6 in RPE. Reverse transcriptase PCR was used to examine the presence of TRPV5 and TRPV6 mRNA in cultured human RPE. Protein expression was assessed by western blotting using TRPV5- and TRPV6-specific antibodies. Immunocytochemistry was employed to examine subcellular localization of TRPV5 and TRPV6 in frozen, formaldehyde-fixed sections of native RPE-choroid tissue and in cultured human RPE monolayers. Finally, TRPV5/TRPV6 ...