OBJECTIVETo determine the role of 1,25(OH)2D3 on the secondary dentin formation and mineralization of the mice.

METHODSThe differences of the mandible mineralization between the wild-type and 1-alpha-hydroxylase gene knockout mice at 6 weeks old were assessed by hematoxylin-eosin (HE) staining, immunohistochemistry, alkaline phosphatase (ALP) histochemistry staining.

RESULTSThe ratio of caries were increased significantly, while the secondary dentin was reduced significantly, the deposition of type I collagen and osteocalcin on the secondary dentin of occlusion surface was decreased significantly, but the deposition of the Biglycan on the dentin was increased significantly, the active of ALP on the odontoblasts were reduced significantly in 1-alpha-hydroxylase gene knockout mice compared to that in the wild-type littermates.

CONCLUSION1,25(OH)2D3 deficiency lead to a defect in the secondary dentin formation and mineralization and caries of the mice.

Animals ; Dentin ; Dentin, Secondary ; Mandible ; Mice ; Osteocalcin

OBJECTIVETo observe sclerotic dentin bonding interfacial nanoleakage used total-etching system and self-etching system by confocal laser scanning microscope (CLSM).

METHODS12 maxillary bicuspids with non-caries, natural cervical sclerotic lesions were divided into three groups. Artifically prepared wedge-shaped lesions were made in 12 sound maxillary bicuspids and divided into three groups as controls. Three kinds of dentin bonding agents, Single Bond (SB), Clearfil SE Bond (CB) and Xeno III (XB), were applied on the surface of the wedge-shaped lesion dentins according to the manufacturer' s instruction. The apical foramens were occluded with self-curing resin. Six specimen groups were individually exposed to 0.1% rhodamine B isothiocyanate in 50% alcohol solutions for 24 h. Then the teeth were section using slow saw and observed the specimens under CLSM.

RESULTSTwo-way ANVOA revealed significant influence of both type of the dentin substrate and the adhesive systems tested on the lengths of the dye-penetrated pathways, representing the amount of nanoleakage (P < 0.05). The lengths of the dye-penetrated pathways were longer in SB than in CB and XB, whatever in normal dentin or sclerotic dentin (P < 0.05). While the extension of nanoleakage were similar in CB and XB (P > 0.05). There was no statistical significance in the amount of nanoleakage in normal dentin and sclerotic dentin using SB (P = 0.148). In CB and XB, the amounts of nanoleakage in normal dentin were higher than in sclerotic dentin (P < 0.05).

CONCLUSIONThe nanoleakage phenomena of bonding interface were observed in three bonding adhesives. In sclerotic dentin bonding interfaces, these nanoleakage phenomenon were located among resin and normal dentin as well as sclerotic dentin.

Acid Etching, Dental ; Bisphenol A-Glycidyl Methacrylate ; Dentin ; Dentin, Secondary ; Dentin-Bonding Agents ; Humans ; Resin Cements

OBJECTIVETo investigate the ultrastructure character of sclerotic dentin surface conditioned by the Er, Cr: YSGG laser and acid etching.

METHODSSixteen human teeth with sclerotic dentin were randomly assigned to 4 groups, and conditioned with acid etching (Group A), laser irradiation (Group B), laser irradiation after acid etching (Group C), or acid etching after laser irradiation (Group D) respectively. The characters of surface ultrastructure were observed using scanning electron microscope (SEM).

RESULTSIn Group A, the majority of dentin tubules were blocked by sclerotic rods. In Group B, the honeycomb-like change was found on the sclerotic dentin surface. The surface structure of Group C was similar to that of Group B. In group D etching wiped off the honeycomb-like structure.

CONCLUSIONSThe sclerotic dentin surface treated with laser irradiation turns into uniform honeycomb-like structure. The rough surface may be beneficial to bonding strength on sclerotic dentin after laser irradiation.

Dentin ; radiation effects ; ultrastructure ; Dentin, Secondary ; ultrastructure ; Humans ; Lasers, Solid-State

Age estimation is important in the practice of forensic science to establish the identity of human remains, as well as with living persons. Particularly in Korea, age estimation in adults has been increase in the demand for incorrect birth records in order to be entitled to civil liability, social benefits, employment. The reduction of pulp cavity size as a result of secondary dentin deposit with increasing age could be used to estimate age. This regressive change can be analyzed using radiological techniques; thus, a variety of methods for dental age estimation based on this approach have been proposed. The purpose of this study is to evaluate the concurrence between the Drusini's method and the Jeon's method using the mandibular first molar on orthopantomographs (OPGs) in Korean adults. A total of 232 OPGs (91 females and 141 males) of Korean individuals with ages ranging from 20 to 69 years were analyzed using Drusini's method and Jeon's method. Our results revealed that the correlation of the two methods with age was statistically significant (r=0.501). Both Drusini's method and Jeon's method showed significant correlation with chronological age, and Jeon's method showed a greater correlation with chronological age (r=0.738) than Drusini's method (r=0.586). The mean absolute error was 7.99 years for Jeon's method and 9.79 years for Drusini's method. Our results demonstrate that Jeon's method using the mandibular first molar on OPGs is a practical and suitable method for age estimation in Korean adults.
Adult* ; Age Determination by Teeth ; Birth Certificates ; Dentin ; Dentin, Secondary ; Employment ; Female ; Forensic Sciences ; Humans ; Korea ; Methods* ; Molar* ; Radiography

OBJECTIVETo investigate the effect of Nd:YAG laser on microtensile bond strength of single bond adhesive system for non-carious sclerotic dentin.

METHODSTen human molars with occlusal wearing were cut into equal halves (nearly 12 mm(2)), and randomly divided into experimental group and control group. The teeth in experimental group were processed with Nd:YAG laser (1 W, 10 Hz), and then applied with Scotchbond and filled with Z350 resin. In control group, the teeth were processed with single bond and filled with Z350 resin. The specimens were sectioned, and the microtensile bond strengths of each sample was tested by a universal testing machine.

RESULTSThe bond strength of the experimental group [(26.11 ± 1.62) MPa] was significantly higher than that of the control group [(22.27 ± 2.16) MPa], P < 0.05. Stero-microscope examination indicated that most of the fractures occurred in dentin-resin interface.

CONCLUSIONSNd:YAG laser can increase the microtensile bond strength of single bond adhesive system in non-carious sclerotic dentin.

Bisphenol A-Glycidyl Methacrylate ; Dental Bonding ; Dental Cements ; Dental Stress Analysis ; Dentin ; Dentin, Secondary ; Dentin-Bonding Agents ; Humans ; Lasers, Solid-State ; Molar ; Resin Cements ; Tensile Strength

OBJECTIVETo observe the bonding interface of sclerotic dentin after treated with total-etching system and self-etching system by confocal laser scanning microscope (CLSM).

METHODSA total of 12 maxillary bicuspids with non-caries, natural cervical sclerotic lesions were divided into three groups. The sclerotic dentin was bonded with Single Bond (SB, total-etching adhesive), Clearfil SE Bond (CB, two-step self-etching) and Xeno III (XB, one-step self-etching) according to the manufacturer's instruction. Artificially prepared wedge-shaped lesions made in sound maxillary bicuspids and bonded with same adhesive were used as control. The primer component was labeled with Rhodamine B Isothiocyanate. Hybrid layer and resin tag of dentin bonding interface were observed by CLSM.

RESULTSTwo-way ANVOA revealed significant influence of both the type of dentin and the bonding adhesive systems tested on resin tag and hybrid layer (P<0.05). Resin tag and hybrid layer in total-etching adhesive (SB) were longer and thicker than in self-etching adhesive (CB, XB) whatever in normal dentin or sclerotic dentin, while the resin tag and hybrid layer thickness were similar in two kind self-etching adhesive (P<0.05).

CONCLUSIONThe resin rags were fewer and shorter and the hybrid layers were thinner in sclerotic dentin than in normal dentin. When bonding the same type dentin substrate, the resin rags were shorter and the hybrid layer thinner in used self-etching adhesive than total-etching.

Acid Etching, Dental ; Bisphenol A-Glycidyl Methacrylate ; Dental Bonding ; Dentin ; Dentin, Secondary ; Dentin-Bonding Agents ; Humans ; Methacrylates ; Microscopy, Electron, Scanning ; Resin Cements

OBJECTIVETo evaluate the beagles' pulp response following direct pulp capping with Clearfil SE BOND (SB).

METHODS130 sound teeth were used. 120 had their pulps mechanically exposed and were divided in two groups. In group A, teeth were capped with SB. In group B, teeth were capped with calcium hydroxide (CH). The left 10 teeth were used as control. After 7, 30 and 90 days, the teeth were extracted and processed for light microscopical examination.

RESULTSIn 7 day observation period, inflammatory reaction in SB group was slighter than that of CH group, but the difference was statistical insignificant. In the 30 day and 90 day observation period, inflammatory reaction was slight in both groups, but specimens with dentin bridge formation was significantly less in SB group than in CH group (P < 0.05).

CONCLUSIONSB showed acceptable biocompatibility with pulp, but its ability to induce hard tissue barrier on pulp exposure is weaker than CH.

Adhesives ; Calcium Hydroxide ; Dental Pulp ; Dental Pulp Capping ; Dentin, Secondary ; Humans ; Resin Cements ; Root Canal Therapy

Dental pulp tissue plays a role in forming dentin, providing nutrition, conducting pain, and generating protective responses to environmental stimuli. Bacterial infection is the main cause of pulp disease, where histopathological changes are the histological basis for determining the choice of treatment and the evaluation of therapeutic effect. Thus, particular attention should be given to eliminate infection, as well as preserve and maintain pulpal health in teeth that show reversible or limited pulpal injuries. Vital pulp therapy, especially its indications and prognostic factors, has been a research hotspot that often causes confusion among clinicians. In this paper, we briefly introduce the confusion and solution for vital pulp therapy in terms of indications, pulp condition assessment, infection elimination, and capping material selection. In addition, we develop a clinical pathway and an operation normalization of vital pulp therapy to better perform the therapy.
Dental Care ; Dental Pulp ; Dental Pulp Capping ; Dental Pulp Diseases ; Dentin, Secondary ; Humans

There have been many radiographic studies on age estimation that evaluate reduction in size of dental pulp cavity with secondary dentin formation. The Paewinsky method reported high accuracy in estimating ages by measuring the width of the pulp cavity in panoramic radiographs. The aim of this study was to evaluate the application of the Paewinsky method to digital periapical radiographs. This study was conducted on 103 cases that reported to the Section of Human Identification of the National Forensic Service. The age was calculated by applying the Paewinsky method that measures the root and pulp canal width at three points in a tooth. The estimation results were compared with those calculated by the Johanson method. When the Paewinsky models were applied to digital periapical radiographs, the errors were significantly greater as compared to the original study. The errors of the maxillary second premolar and mandibular lateral incisor were greater than those of the maxillary central incisor, lateral incisor, mandibular canine, and first premolar. Furthermore, errors of the age estimation models in level C were greater than those in levels A and B. This study could be a reference for the application of the Paewinsky method to digital periapical radiographs.
Age Determination by Teeth ; Bicuspid ; Dental Pulp Cavity ; Dentin, Secondary ; Forensic Anthropology ; Incisor ; Methods ; Radiography, Dental ; Tooth

OBJECTIVE: To assess the feasibility and efficacy of simvastatin-collagen composite sponge as a novel, direct pulp capping material. METHODS: A total of 120 Sprague-Dawley rats were randomly divided into three groups: the simvastatin-collagen composite sponge group (SIM group), the collagen sponge group (CS group), and the Ca(OH)2 group (CH group). An endodontic entry cavity was prepared on the occlusion of the first molar on the left maxillary of each rat. The contralateral teeth were utilized as the normal control group. The rats were experimented after 1, 3, 7, 14, and 28 days. X-ray observations were conducted and the specimens underwent hematoxylin-eosin (HE) and Masson's Thichrome staining. Dentin bridge formations and pulpal biology reactions were evaluated histopathologically. RESULTS: X-ray results: high-density images could be observed on the pulp exposure sites in the CH group on the 28th day. In the SIM group, high-density images could be observed after 14 and 28 days, whereas in the CS group, high-density images were not observable in the exposed area. HE and Masson's Thichrome staining results: different degrees of inflammation under the cavity were detected in the three groups at different time points. The inflammatory reaction of the CS group was the most serious. The degree of the inflammatory reaction varied significantly between the SIM and the CS groups on the 14th and 28th days (P<0.01). The inflammatory reaction in the SIM group was lighter than in the CH group. There was a statistical difference between the SIM and the CH groups on the 14th day (P<0.05). During the observation period, the SIM group induced the best and fastest formation of reparative dentin. As for dentin bridge formation, a significantly higher complete bridge rate was observed in the SIM group than in the CH and in the CS groups on the 14th day (P<0.05) and for the SIM and the CH groups compared with the CS group on the 28th day (P<0.05). CONCLUSIONS The simvastatin-collagen composite sponge exhibited satisfactory biocompatibility with the pulp tissue and promoted the formation of reparative dentin. The application of simvastatin-collagen composite sponge as a pulp-capping material has satisfactory potential.
Animals ; Calcium Hydroxide ; Collagen ; Dental Pulp ; Dental Pulp Capping ; Dental Pulp Exposure ; Dentin, Secondary ; Molar ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Simvastatin