Purpose: Fiber-reinforced composite posts (FRC posts) with adhesive resin cement systems are used for post-and-core build-up on endodontically treated teeth. The objective of this study was to compare the retention force of posts built up by the direct technique and bonded with different adhesive systems.
 Methods: Post spaces 3 mm in diameter and 4 mm in depth were drilled on endodontically treated bovine roots. FRC posts were built up and then luted with three adhesive systems: a self-adhesive resin cement, a conventional composite-type adhesive resin cement with self-etching primer, and a normal bonding system combined with resin composite. The samples were stored in water for 1 or 14 days. Retention force was measured using the pull-out method with a universal testing machine. The maximum load was recorded as the retention force of the post.
 Results: No significant differences in retention force among adhesive systems were found in the 1-day samples. Conventional composite-type resin cement showed the largest retention force in the 14-day samples. In terms of failure mode, cohesive failure of resin cement was the most common.
 Conclusion: This study investigated the retention force of directly-built FRC posts bonded with adhesive resin cements. There were no significant differences among the adhesive systems in the 1-day samples. Although the retention force of the FRC post built-up with self-adhesive resin cement after 14 days storage was smaller than that of conventional composite-type resin cement, this value was similar to that of the normal bonding system.

View full abstract

 Purpose: In this study, the interaction between the acidic monomer MDP employed in Clearfil Tri-S Bond ND and enamel or dentin was examined in detail by comparing the changes in the carbon 13 nuclear magnetic resonance (¹³C NMR) spectrum obtained before and after reaction with enamel and dentin particles using a solid-state and liquid-state ¹³C NMR technique. The effect of the demineralization ratio of tooth apatite by acidic monomer MDP on the shear bond strength to enamel and dentin was examined.
 Methods: Bovine crown enamel particles or bovine crown dentin particles of 0.400 g were suspended in 2.000 g of Clearfil Tri-S Bond ND, and the suspensions were vibrated for 10 minutes. After centrifuging these suspensions, liquid-state ¹³C NMR spectra of the supernatant solution of adhesives were observed using an EX-270 spectrometer. The ratio of intensity of the NMR peak of the vinyl methylene carbon for acidic monomer MDP employed in Clearfil Tri-S Bond ND to the NMR peak of that for HEMA detected in the ¹³C NMR spectrum was determined before and after reaction with enamel or dentin particles. The reduction in the peak intensity for MDP was determined by dividing the difference in the intensity ratio obtained before and after reaction by the intensity ratio obtained before reaction. The reduction was determined as the ratio of demineralization of tooth apatite by MDP. Furthermore, the bond strength of Clearfil Tri-S Bond ND to ground enamel and dentin was measured.
 Results: When Clearfil Tri-S Bond ND interacted with enamel and dentin, the demineralization ratio of tooth apatite by acidic monomer MDP was 33.00% and 40.50%, respectively. In addition, the bond strength of Clearfil Tri-S Bond ND to the enamel showed a value of 15.04 MPa, and the bond strength to dentin showed a value of 17.39 MPa.
 Conclusions: Based upon the foregoing, dentin showed a higher decalcification ratio of the tooth substance apatite ingredient of MDP combined with Clearfil Tri-S Bond ND than enamel. In addition, regarding the influence on bond strength, it significantly adhered to the dentin which showed a higher decalcification ratio of MDP than enamel.

View full abstract

 Purpose: The purpose of the present study was to clarify the mechanism and applicability of calcium phosphate based paste as a tooth care material (hereafter, “AP paste”) that was designed on the principle of calcium phosphate cement. The study examined: 1) percolate modality of the elements derived from AP paste, 2) identification of the precipitated apatite crystals in dentin, and 3) crystal growth of apatite in dentin.
 Methods: Extracted human permanent teeth were used in this study. (1) Element analysis: The analysis evaluated the distribution and percolate modality of elements derived from AP paste to dentin. Dentin samples having experimental windows were demineralized with 50 mmol/l acetic acid for three days. AP paste was then applied to the windows three times a day for two weeks. The samples were embedded in epoxy resin and sectioned. The highly polished sections were observed with secondary electron images and back-scattered electron images. Semi-quantitative analysis was also performed for Ca, P and F elements using an electron probe micro analyzer (EPMA). (2) Transmission electron microscopy (TEM) : The samples were evaluated for crystal morphological observation and crystal identification using TEM and electron diffraction pattern, respectively, with references of HAp, tetra-calcium phosphate (TTCP) and calcium hydrogen phosphate anhydrous (DCPA).
 Results: 1) EPMA analysis confirmed that Ca, P and F elements obviously percolated to and accumulated in dentin; 2) Newly formed crystals were precipitated in the dentin surface and dentinal tubules. The electron diffraction pattern confirmed that those crystals were apatites; 3) The application of AP paste caused the mineral contents in demineralized dentin to regain the normal level of mineral contents in intra- and inter-tubular dentin. Distinct crystal growth and remineralization were exhibited by comparing the a- and c-axis of the crystals.
 Conclusion: TTCP and DCPA in the paste released calcium and phosphate ions, and the ions clearly promoted crystal growth in demineralized dentin. Thus, it is considered that the AP paste would promote dentin calcification to a higher degree as a biocompatible material.

View full abstract

 Purpose: Cryptotanshinone (CPT) isolated from the root of an Asian medicinal plant, Salvia miltiorrhiza bunge, acts as a potent anti-tumor or anti-inflammatory agent in vitro. However, the effects of CPT on the progression of periodontitis are still unknown. This study investigated the effects of CPT on the production of inflammation-related molecules in human gingival fibroblasts.
 Methods: Human gingival fibroblasts (HGFs), CRL-2014^TM (ATCC), were used. Cytotoxicity of the cells by CPT was examined. Dead cells stained by trypan blue were counted and analyzed. Next, the levels of IL-6 and VEGF in IL-1β-treated cells with or without CPT were measured using ELISA kits. The productivity of cathepsin L in IL-1β-treated cells with or without CPT was examined using Western blotting.
 Results: The ratio of viable cell numbers was significantly decreased by 100 μmol/l CPT. Next, the increase of IL-6 and cathepsin L induced by IL-1β was significantly suppressed by the pretreatment of 10 μmol/l CPT in HGFs. On the other hand, productivity of VEGF induced by IL-1β was not changed by the pretreatment of 10 μmol/l CPT.
 Conclusion: CPT suppresses IL-1β-induced IL-6 and cathepsin L production in HGFs, and might regulate the progression of periodontitis.

View full abstract

 Purpose: In order to achieve a comprehensive oral health assessment, a new salivary multi-test system (AL-55) has been developed. This test system can assay seven saliva analytes measuring color changes of the test strip as reflectance: [Dental caries] cariogenic bacteria, pH, buffer capacity, [Periodontal disease] blood, leukocyte, protein, [Oral cleanliness] ammonia. The purpose of this study was to evaluate the clinical efficiency of this system by examining the correlation between oral conditions and reflectance measured by AL-55.
 Methods: Oral rinse samples (3 ml-DW, 10 sec rinse) were collected from 231-adults (40.3±12.8 y). Ten μl of the sample was dropped on each pad of the strip, and the reflectance was measured after 1 and 5 min. After collecting the samples, the oral conditions of the subjects were examined: [Dental caries] DMFT, [Periodontal disease] probing pocket depth (PPD), bleeding on probing (BOP %), gingival index (GI) and Community periodontal index (CPI), [Oral cleanliness] total number of bacteria. The correlation between the oral conditions and the reflectance was assessed with the Spearman correlation test (p<0.01). In addition, the subjects were stratified into 3 groups (high, middle and low) on the basis of DMFT, PPD or total number of bacteria. The reflectance between the groups was compared with Tukey’s test (p<0.05).
 Results: [Dental caries] DMFT was significantly correlated with reflectance of cariogenic bacteria measured by AL-55, and was not correlated with pH and buffer capacity. There was a significant difference in reflectance of cariogenic bacteria between high and low groups stratified by DMFT. In the cases of pH and buffer capacity, no significance was found between the three groups. [Periodontal disease] PPD, BOP, GI and CPI were significantly correlated with blood, leukocyte and protein measured by AL-55. There were significant differences in blood between the three groups stratified by PPD, while leukocyte and protein exhibited significant differences between high and middle groups and between high and low groups. [Oral cleanliness] The total number of bacteria was significantly correlated with ammonia measured by AL-55. There are significant differences in ammonia between the three groups stratified by the total number of bacteria.
 Conclusion: This particular study revealed that the oral conditions associated with dental caries, periodontal disease and oral cleanliness were correlated with the reflectance measured by the newly-developed salivary multi-test system (AL-55). These results may indicate clinical usefulness of this system for assessing oral health.

View full abstract

 Purpose: We hereby report a case of chronic periodontitis with drug-induced gingival overgrowth that was successfully treated by initial preparation, surgical periodontal therapy and prosthetic treatment. At the patient’s initial visit, she had difficulty in masticating. Evaluating masticatory performance over time using the referential guideline for the evaluation of masticatory efficiency provided motivation and guidance for her and she has shown significant improvement without evidence of recurrence for 5 years.
 Patient condition and treatment procedure: A 59-year-old woman visited our hospital with the chief complaint of gingival swelling. She had been experiencing gingival swelling for about 6 months but had not visited a hospital due to the absence of pain. However, her conditioned worsened and she began to feel pain in her gingiva one month prior to visiting the hospital. After visiting her General Practitioner (GP) she was referred to our university hospital for specialized care on January 21, 2008. She had been taking nifedipine for hypertension for 5 years. A Probing periodontal Pocket Depth (PPD) of ≥4 mm was found at 100% of the sites and fibrous hyperplasia of the gingiva was observed on her upper anterior teeth and teeth in the molar area. Radiography revealed wide bone resorption around the root apexes of the lower anterior teeth, and many of the crowns of teeth in the molar area were severely damaged and could not be treated. Therefore, the patient was diagnosed as having severe generalized chronic periodontitis with drug-induced gingival overgrowth. As an initial periodontal treatment, we gave Tooth Brushing Instructions (TBI), extracted the teeth that were severely damaged and untreatable, performed dental Scaling and Root Planing (SRP), and placed a treatment denture. Following reexamination after the initial treatment of periodontitis, surgical periodontal therapy was performed to flatten the alveolar bone. Upon confirming that the condition of periodontium had stabilized, we performed a malocclusion by provisional restorations. The prosthetic treatment was followed up with Supportive Periodontal Therapy (SPT). It has been 4 years and 8 months since SPT began and the patient’s periodontal tissues been kept in good condition. The patient’s difficulty in masticating presented on her initial visit has seen gradual improvement through dietary counseling using the referential guideline for the evaluation of masticatory efficiency. Also, we conducted a histological observation of the gingival tissue that was collected during surgical periodontal therapy. We observed acanthosis and irregularly elongated rete pegs in the dental epithelium, and found thick dense bundles of collagen fibers in the connective tissue. A number of positive cells of Proliferating Cell Nuclear Antigen (PCNA) were observed in the basal layer and parabasal layer of the epithelium.
 Conclusion: Evaluating masticatory performance over time using the referential guideline for the evaluation of masticatory efficiency can more reliably establish gradual improvement in masticatory efficiency of a patient with severe chronic periodontitis.

View full abstract

 Objectives: Three types of periodontal regeneration therapies are currently used in Japan: bone graft (β-Tricalcium Phosphate : β-TCP), guided tissue regeneration (GTR) method, and application of enamel matrix derivative. Here, we report a case in which favorable results were obtained using the GTR method with a bone graft for a patient with moderate chronic periodontitis whose condition was aggravated by occlusal trauma.
 Case: A 58-year-old female patient was presented with the chief complaint of gingival bleeding around the maxillary right canine teeth. She was also referred to her home dentist for periodontal tissue regeneration therapy. She had a history of both dental caries and prosthetic treatment at her home dental clinic since 1975, when she was 27 years old.
 The mean probing depth (PD) at the first visit to our hospital was 3.6 mm; the percentage of tooth sites with PD ≥4 mm was 43.5%; the rate of Bleeding on Probing (BOP) was 28.3%; and the O’Leary’s plaque control record was 60.8%. No inflammation was observed in the area of the marginal gingiva; however, blood stasis was observed around the maxillary anterior teeth. The overlap of the anterior teeth included an overjet of 2 mm and an overbite of 3 mm. Although horizontal bone resorption around most of the teeth was shown, the marked vertical bone resorption was around 13 and 22, and the radiolucency in the furcation area of 47 and apical area of 48 were visible on X-ray findings. After the initial therapy was completed, the area rate of PD ≥4 mm was reduced to 5.8%. Periodontal regenerative therapy was applied for the area that surrounds PD ≥4 mm around the maxillary teeth. Following periodontal surgery, we had planned to send the patient back to her home dentist. However, the patient requested comprehensive treatment at our department; therefore, we consulted her home dentist and revised the treatment plan.
 The improvement of the patient’s clinical parameters is currently stable; however, the site of PD 5 mm without BOP still remained in the center of 47. Therefore, we are continuing supportive periodontal therapy for the patient.
 Conclusion: In this case, we performed the GTR method accompanied by a bone graft for severe vertical bone loss. The periodontal tissue condition has remained stable for 6 years after surgery.

View full abstract