Effects of Diabetes on Elemental Levels and Nanostructure of Root Canal Dentin.

INTRODUCTION: This study evaluated the effects of diabetes mellitus (DM) on the nanostructure of root canal dentin using high-resolution transmission electron microscopy (HRTEM) and inductively coupled plasma mass spectrometry (ICP-MS). METHODS: Twenty extracted human premolars from diabetic and nondiabetic patients (n = 10 in each group) were decoronated and sectioned horizontally into 40 2-mm-thick dentin discs, with each disc designated for a specific test. ICP-MS was used to determine the different elemental levels of copper, lithium, zinc, selenium, strontium, manganese, and magnesium in diabetic and nondiabetic specimens. HRTEM was used to analyze the shape and quantity of the apatite crystals in diabetic and nondiabetic dentin at the nanostructural level. Statistical analysis was performed using Kolmogorov-Smirnov and Student t test (P < .05). RESULTS: ICP-MS revealed significant differences in trace element concentrations between the diabetic and nondiabetic specimens (P < .05), with lower levels of magnesium, zinc, strontium, lithium, manganese, and selenium (P < .05), and higher levels of copper in diabetic specimens (P < .05). HRTEM revealed that diabetic dentin exhibited a less compact structure with smaller crystallites and significantly more crystals in the 2500 nm2 area (P < .05). CONCLUSION: Diabetic dentin exhibited smaller crystallites and altered elemental levels more than nondiabetic dentin, which could explain the higher root canal treatment failure rate in diabetic patients.

Functional role of inorganic trace elements in dentin apatite tissue-part III: Se, F, Ag, and B.

Dentin hydroxyapatite possesses a unique versatile structure which allows it to undergo ionic substitutions. Trace elements play pivotal roles within the oral cavity, especially in dentin apatite tissue. Therefore, it is critical to explore the role of these elements in dentin apatite structure. The roles of other inorganic elements in dentin apatite were discussed in part I (Mg, Sr, Zn, and Fe) and part II (Cu, Mn, Si, and Li) of these series. In the last part of the review series, the role of selenium, fluorine, silver, and boron in the regulation of dentin apatite structure and function was discussed. We evaluated how these elements affect the overall size, morphology, and crystallinity of dentin apatite crystals. Moreover, we investigated the importance of these elements in regulating the solubility of dentin apatite. An electronic search was performed on the role of these trace elements in dentin apatite from January 2010 to January 2022. The concentration of selenium in teeth has been explored only recently, particularly its incorporation into dentin apatite. Silver nanomaterials inhibit the growth of cariogenic microorganisms as well as arrest the degradation of collagen. Fluorine was found to have important roles in dentin remineralization and dentinal tubule occlusion, making it widely used for hydroxyapatite doping. Boron is critical for mineralized tissues like bone, dentin, and enamel, but its exact role in dentin apatite is unknown. Therefore, understanding the impact of these elements on dentin apatite is potentially transformative, as it may help to fill a significant knowledge gap in teeth mechanics.

Effect of biomaterials on angiogenesis during vital pulp therapy.

This review intended to provide an overview of the effects of dental materials, used in dentin-pulp complex and dental pulp regeneration, on angiogenesis processes during regenerative endodontic procedures. An electronic search was performed in PubMed and MEDLINE databases via OVID using the keywords mentioned in the PubMed and MeSH headings for English language published articles from January 2005-April 2014 that evaluated the angiogenic properties of different dental materials used in regenerative endodontic procedures. Of the articles identified in an initial search, only 40 articles met the inclusion criteria set for this review. Vital pulp therapy materials might have positive effects on angiogenesis events, while most of the canal irrigating solutions and antibiotic pastes have anti-angiogenic activity except for EDTA. Future clinical studies will be helpful in defining the mechanisms of action for dental materials that promote or inhibit angiogenesis events at applied areas.

Repair of bone defect by nano-modified white mineral trioxide aggregates in rabbit: A histopathological study

BACKGROUND: Many researchers have tried to enhance materials functions in different aspects of science using nano-modification method, and in many cases the results have been encouraging. To evaluate the histopathological responses of the micro-/nano-size cement-type biomaterials derived from calcium silicate-based composition with addition of nano tricalcium aluminate (3CaO.Al2 O3 ) on bone healing response. MATERIAL AND METHODS: Ninety mature male rabbits were anesthetized and a bone defect was created in the right mandible. The rabbits were divided into three groups, which were in turn subdivided into five subgroups with six animals each based on the defect filled by: white mineral trioxide aggregate (WMTA), Nano-WMTA, WMTA without 3CaO.Al2 O3 , Nano-WMTA with 2% Nano-3CaO.Al2 O3 , and empty as control. Twenty, forty and sixty days postoperatively the animals were sacrificed and the right mandibles were removed for histopathological evaluations. Kruskal-Wallis test with post-hoc comparisons based on the LSMeans procedure was used for data analysis. RESULTS: All the experimental materials provoked a moderate to severe inflammatory reaction, which significantly differed from the control group (p< 0.05). Statistical analysis of bone formation and bone regeneration data showed significant differences between groups at 40- and 60- day intervals in all groups. Absence of 3CaO.Al2 O3 leads to more inflammation and foreign body reaction than other groups in all time intervals. CONCLUSIONS: Both powder nano-modification and addition of 2% Nano-3CaO.Al2 O3 to calcium silicate-based cement enhanced the favorable tissue response and osteogenesis properties of WMTA based materials

Functional role of inorganic trace elements in angiogenesis--Part I: N, Fe, Se, P, Au, and Ca.

Many inorganic elements are recognized as being essential for the growth of all living organisms. Transfer of nutrients and waste material from cells and tissues in the biological systems are accomplished through a functional vasculature network. Maintenance of the vascular system is vital to the wellbeing of organisms, and its alterations contribute to pathogenesis of many diseases. This article is the first part of a review on the functional role of inorganic elements including nitrogen, iron, selenium, phosphorus, gold, and calcium in angiogenesis. The methods of exposure, structure, mechanisms, and potential activity of these elements are briefly summarized. An electronic search was performed on the role of these elements in angiogenesis from January 2005 to April 2014. The recent aspects of the relationship between different elements and their role in angiogenesis, and production of pro- and anti-angiogenic factors were assessed. Several studies emphasized the role of these elements on the different phases of angiogenesis process in vivo. These elements can either enhance or inhibit angiogenesis events. Nitrogen in combination with bisphosphonates has antiangiogenic effects, while nitric oxide promotes the production of angiogenic growth factors. Iron deficiency can stimulate angiogenesis, but its excess suppresses angiogenesis events. Gold nanoparticles and selenium agents have therapeutic effects due to their anti-angiogenic characteristics, while phosphorus and calcium ions are regarded as pro-angiogenic elements. Understanding how these elements impact angiogenesis may provide new strategies for treatment of many diseases with neovascular component.

A novel method to evaluate the neurocompatibility of dental implants.

PURPOSE: To evaluate the neurocompatibility of different types of dental implant surface treatments using the P19 neural cell line. MATERIALS AND METHODS: P19 cells were plated and supplemented with retinoic acid to grow as aggregates for 4 days. Twenty dental implants were selected from four different implant systems with five different surface treatments. The implants were divided into four groups (n=5), placed inside medical rings, and fixed by injection of warm gutta-percha using a thermoplastic injection technique. Implant molds were placed inside graded culture dishes, and culture medium containing P19 neural cells were plated on the dishes for 4 days. After 24 hours, the surfaces of the implant molds were covered with self-curing resin to make a replica of each mold surface. Replicas were assessed under a scanning electron microscope, and the number of cells and the total cells covering the areas were evaluated. Data were analyzed by a post hoc Tukey test. RESULTS: There were significant differences in P19 cell counts between all modified and electropolished surfaces. The highest P19 cell counts were shown on OsseoSpeed and Laser-Lok surfaces. The lowest counts were shown on the Nanotite surface at the collar. OsseoSpeed and Laser-Lok surfaces showed higher counts at the collar than on the body; the opposite was seen for SLActive and Nanotite surfaces. Cell-covered areas on Laser-Lok surfaces showed significantly higher values than the resorbable blasted media (RBM)-treated surfaces, while it was not significantly different from the OsseoSpeed surface of collar regions. SLActive collar regions showed larger cell-covered areas than the SLActive body surfaces, but this was not significant. CONCLUSIONS: All test surface treatments in this study showed better neurocompatibility than control group surfaces. The Laser-Lok, RBM, and OsseoSpeed surfaces were superior to the Nanotite and SLActive surfaces in terms of neurocompatibility.

Protective effect of bilberry extract as a pretreatment on induced oral mucositis in hamsters.

OBJECTIVE: This study evaluated the effect of standardized bilberry extract containing anthocyanosides on chemotherapy-induced oral mucositis in hamsters. STUDY DESIGN: Twenty-four hamsters were randomly chosen and assigned to groups. Groups A and B were pretreated with deionized water, whereas group C was pretreated with bilberry extract daily for 7 days. Groups B and C underwent chemotherapy by intraperitoneal injections of 5-fluorouracil (days 4, 9, and 14); group A received normal saline. Potentiation of oral mucositis was achieved by scratching both cheek pouches of all animals with needles (days 5, 6, and 14). The pouches were histopathologically examined on day 17 after visual examination and blood sampling by cardiac puncture. RESULTS: The bilberry extract group showed significantly lower oral mucositis clinical and histopathologic scores (P < .05) and less percentile of mean daily weight reductions compared with animals receiving vehicle. CONCLUSIONS: Frequent administration of bilberry extract had a protective effect on oral mucosal damage induced by 5-fluorouracil in an animal model.

Healing acceleration in hamsters of oral mucositis induced by 5-fluorouracil with topical Calendula officinalis.

OBJECTIVE: This study assessed the potential of topical Calendula officinalis extract on the healing of oral mucositis induced by 5-fluorouracil (5-FU) in hamsters. STUDY DESIGN: Oral mucositis was induced in 60 male hamsters by 5-FU (60 mg/kg) on days 0, 5, and 10 of the study. The cheek pouch was scratched with a sterile needle on days 1 and 2. On days 12-17, 5% and 10% C. officinalis gel and gel base groups were treated and then compared with a control group. Macroscopic and microscopic scores and weights were evaluated. RESULTS: Microscopic and macroscopic scores of mucositis were lower in the 5% and 10% C. officinalis gel groups than in the gel base and control groups (P < .05). Weight gain was noted in the treatment groups compared with the gel base and control groups (P < .05). CONCLUSIONS: Calendula officinalis extract accelerated the healing of oral mucositis in hamsters.

The efficacy of foam cleaners in removing debris from two endodontic instruments.

OBJECTIVE: To compare the efficacy of ProFile File cleaner and a nanostructured foam in removing debris from two rotary nickel-titanium instruments during and after instrumentation. METHOD AND MATERIALS: Twenty mandibular premolars were decoronated and instrumented up to either no. 40.04 RaCe (no. 40.04) or K3 (no. 40.04) instruments (n = 10). Each group of files was randomly divided into two groups: ProFile File cleaner and Nano Foam cleaner. The instruments were examined under a scanning electron microscope (SEM) before and after placement into the canals. Subsequently, instruments were introduced into each cleaner and examined again under SEM. The amount of debris removal from the instruments was determined by ImageJ software. Data were subjected to Kruskal-Wallis and Mann-Whitney tests at a .05 level of significance. RESULTS: The amount of debris removal was significantly different between the groups (P = .002). The amount of debris removed was significantly higher in K3 with Nano Foam cleaner than ProFile File cleaner (P = .009). CONCLUSION: Nanostructured foam can remove debris from endodontic files, especially from those with complex cross-section. This method is recommended to help optimize debris removal with the further possibility of instrument sterilization and reduced risk of cross-contamination.

Effect of MTAD as a final rinse on removal of smear layer in ten-minute preparation time.

INTRODUCTION: The aim of this study was to evaluate the effect of MTAD as final rinse on removal of the smear layer subsequent to primary irrigation with 1.3% sodium hypochlorite (NaOCl) during 10-minute instrumentation periods. METHODS: Forty teeth were divided into 2 experimental groups, each containing 15 teeth, and 1 positive control group of 10 teeth. The canals were prepared with hand and rotary instruments. In the MTAD group, the root canals were flushed with 1.3% NaOCl solution during 10-minute instrumentation, and MTAD was used as the final rinse. In other experimental group, 5.25% NaOCl was used during instrumentation, and 17% ethylenediaminetetraacetic acid (EDTA) was used as the final rinse. In the positive control group, sterile distilled water was used for irrigation. The overall instrumentation period for each canal was 10 minutes. The amount of the smear layer and degree of erosion qualified according to the study by Torabinejad et al by using a scanning electron microscope. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests. All statistical analyses were set with a significance level of α = 0.05. RESULTS: In the positive control group, debris and heavy smear layer covered the root canal surface and the tubules. In MTAD group, moderate smear layer covered the root canal surface and the tubules. In EDTA group, there was no smear layer on surface of canals. There were significant differences between groups (α < 0.0001). Mann-Whitney test showed significant difference between experimental groups (α = 0.01). CONCLUSIONS: In 10-minute instrumentation period, the use of 5.25% NaOCl during instrumentation and 17% EDTA as the final rinse is more effective than using 1.3% NaOCl as primary irrigation and MTAD as final rinse on removal of the smear layer.