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Application of alveolar bone graft (ABG) in alveolar augmentation is done to prevent excessive bone resorption due to tooth extraction, missing teeth, or other diseases/conditions affecting the alveolar bone. The use of autogenous dentin-derived ABG has been considered as the composition of dentin appears to be nearly analogous to that of bone. This systematic review aims to assess the efficacy of dentin-derived ABG for alveolar augmentation of post-extraction sockets or other alveolar bone defects by evaluating volume gain and histomorphometric data. A search of systematic literature was conducted in Pubmed, Scopus, Web of Science, and Embase from database inception to October 2023. The review included both randomized controlled trials (RCT), pilot studies, clinical trials, and retrospective studies reporting on dentin-derived ABG use for alveolar augmentation. Overall, 298 articles were obtained from the initial search. From these articles, 21 articles met the inclusion criteria and were included for descriptive analysis. All of the studies indicated low risk of bias. Studies of dentin-derived ABG, which used bone-derived grafts as the control group, have shown significantly higher percentages of new bone formation, gain in vertical and horizontal dimensions, and less reduction in dimensions. Dentin-derived ABG was effective in volume maintenance, indicating promising results via histomorphometric and radiographic analysis. [Display omitted] [ABSTRACT FROM AUTHOR]

Statement of the Problem: Immediate dentin sealing (IDS) was introduced to overcome the disadvantages of delayed dentin sealing like pollution of dentin tubules, microleakage, and bond strength destruction over time. The effect of IDS on the bond strength of indirect restorations is still debatable.Purpose: This study was conducted to determine the effect of IDS on the bond strength of ceramic restorations to dentin.Materials and Method: In this systematic review and meta-analysis, the study protocol was registered on the PROSPERO database under the registration number CRD420202014 27. MEDLINE (PubMed), Web of Science, Scopus, and ProQuest databases were searched until January 2021 and updated in January 2022. Worldcat.org and Opengrey.eu, ProQuest dissertation and thesis, and Google Scholar were searched to explore the grey literature. The in vitro studies evaluating the bond strength of ceramic restoration to dentin with and without IDS were included. Seven criteria were assessed to evaluate the risk of bias in the study. Statistical analyses were conducted using RevMan 5.3. The inverse variance method was used to determine the mean difference of micro-tensile bond strength (µTBS) and shear bond strength (SBS).Results: A total of 10 studies (20 datasets) were included in the meta-analysis. Regarding the µTBS analysis, IDS had a significantly higher bond strength than Delayed Dentin Sealing (DDS) (MD:1.16, 95%CI:0.28_2.03, I2=0%). However, no significant difference was found between them in the SBS analysis (MD:0.25, 95%CI: -0.56-1.06, I2=96%). All studies were categorized to have a moderate or high risk of bias.Conclusion: Most in vitro evidence showed favorable results for the effect of IDS on the bond strength and durability of indirect restorations. The adhesive system and the type of ceramic and its treatment before cementation are determining factors. Due to the heterogeneity of the outcomes and studies with a moderate/high risk of bias, the quality of the evidence was low.

Enterococcus faecalis is the main pathogen causing refractory apical periodontitis (RAP). This bacterium can tolerate harsh environments and trigger periapical immune inflammatory responses that result in persistent infection inside and outside the root canal. Adhesion to the dentin wall of root canals and the subsequent formation of biofilms significantly enhances the drug resistance and anti-erosion ability of Enterococcus faecalis, which is the key factor mediating its pathogenesis. The adhesion of Enterococcus faecalis to dentin involves non-specific adhesion and specific adhesion, and the latter is mediated by adhesion-related virulence factors, mainly including the adhesin of collagen from enterococci (Ace), extracellular surface protein (Esp), gelatinase (GelE), serine protease (SprE), endocarditis and biofilm associated pilus (Ebp) and aggregation substance (AS), which is regulated by multiple two-component systems. The two-component system Fsr can promote the expression of gelE and sprE when the cell population density increases. GelE can further reduce Ace, while the two-component system GrvRS directly downregulates ace expression in response to the serum environment. The two-component systems CroRS and WalRK may also promote and inhibit the expression of various virulence factors, including ace and gelE, thus affecting the adhesion of Enterococcus faecalis. In addition, the mechanochemical preparation and the internal environment of the root canal can also influence the adhesion of Enterococcus faecalis to dentin. Avoiding the introduction of Enterococcus faecalis and using adhesion-interfering medications during root canal treatment can effectively prevent the adhesion of Enterococcus faecalis, and a variety of activated irrigation protocols can also be effective at increasing the clearance of Enterococcus faecalis from the root canal. The design of rational drugs targeting key factors involved in and regulators of the adhesion of Enterococcus faecalis to dentin is expected to provide new ideas and strategies for root canal infection control. The present paper reviews the adhesion of Enterococcus faecalis to dentin and its influencing factors.

Statement of the Problem: Although various kinds of research have been conducted to compare the physical and chemical properties of dentin and enamel in animal and human samples, proving the ability of animal dentin material as a good substitute for human specimens is always a challenge for experimental studies.Purpose: The aim of the present study is to investigate whether the changes in the dentin microhardness of animal samples are similar to those of human samples or not.Materials and Method: In this in vitro study, sixty single-rooted human, bovine, and ovine teeth (n=20 in each group) were decoronated at CEJ. The remaining roots were embedded in acrylic resin and a cross-section cut was made in the middle of the samples in order to achieve dentin disks. All of the 120 samples were randomly assigned to three control (n=20 for each group) and three experimental groups (n=20 for each group). In the experimental groups, calcium hydroxide with a creamy consistency was prepared and the disks were embedded in dishes containing calcium hydroxide. Control groups were embedded in physiological saline. The samples were incubated for seven days at the 37oC and Vickers microhardness test was performed immediately. The average of three yielded values was considered as the final value of microhardness. Data were analyzed using two-way ANOVA, one-way ANOVA, and Tukey’s post hoc tests.Results: In the control group, the human samples showed the highest microhardness value, while the bovine teeth had the lowest microhardness value (p< 0.001). In the calcium hydroxide group, the human samples showed the highest microhardness value in comparison to bovine and ovine to teeth. However, no significant difference was observed between the bovine and ovine samples in microhardness value.Conclusion: Based on our research, substituting bovine and ovine samples with human samples in experimental studies is not recommended. Nevertheless, more studies are needed in this regard.

Objective To explore the effect of Morinda citrifolia juice (MCJ) combined with ethylene diamine tetraacetic acid (EDTA) on premolar bonding strength and nanoleakage and compare the results with those of the most commonly used root canal irrigation solution, sodium hypochlorite (NaClO), to provide a reference for clinical application. Methods This study was approved by the ethics review committee. Sixty-three human premolars extracted for orthodontic treatment were randomly divided into a control group (distilled water group) and 6 experimental groups according to the different rinsing solutions used after the surface enamel was removed. The experimental groups included Group A (2.5% NaClO), Group B (5.25% NaClO), Group C (6% MCJ), Group D (2.5% NaClO-17% EDTA), Group E (5.25% NaClO-17% EDTA), and Group F (6% MCJ-17% EDTA) (n = 9). After soaking in the corresponding rinsing solution for 20 minutes, they were layered and stacked on their surfaces to form 4 mm × 4 mm × 3 mm Z350 resin blocks. Six samples from each group were cut into 1 mm × 1 mm × 8 mm specimen strips for microtensile bonding strength testing. The fracture type was determined under a stereomicroscope, and the remaining 3 samples from each group were aged and cut into 1 mm thick slices for interface nanoleakage testing and scanning electron microscopy observation of the resin dentin bonding interface. Results There were significant differences in the microtensile bonding strength among the groups (PP

As the main means of mastication, teeth can withstand countless functional contacts. The mechanical properties of teeth are closely related to their tissue structure. Enamel and dentin have a high hardness and modulus of elasticity, and their graded structure allows them to withstand bite forces without being susceptible to fracture. When tooth tissue is defective, full crown restoration is often needed to restore the normal shape and function of the tooth. Metal materials, ceramic materials, and polyetheretherketone (PEEK) materials are commonly used for crown restoration. Metal materials have certain disadvantages in terms of aesthetics and are relatively rarely used in clinical practice. Ceramic materials with different compositions exhibit differences in performance and aesthetics, but their elastic modulus and hardness are much higher than those of dental tissue, resulting in mismatching mechanical properties. In contrast, the elastic modulus of PEEK is lower than that of tooth tissue and similar to that of bone tissue, but its properties can be improved by fiber reinforcement. Notably, when the mechanical properties of a restoration material and tooth tissue are not fully matched, the interface between them often forms a potential weak link, which ultimately affects the stability and long-term effect of the restoration. This article introduces the mechanical properties and corresponding structural characteristics of enamel and dentin. On this basis, the advantages and limitations of existing restoration materials are analyzed, and the possibility of biomimetic design of full crowns is further explored.

Abstract The study aimed to compare various toothpastes and mouthwashes on permanent tooth dentin after erosive and abrasive challenges. 130 sound premolars dentin were randomly submitted to an initial erosive challenge and a cycle of erosive and abrasive challenges for five days. The five experimental groups (n = 26) were: (1) Control group (artificial saliva), (2) Elmex erosion protection toothpaste and mouthwash, (3) Vitis anticaries biorepair toothpaste and mouthwash, (4) Oral B Pro-expert toothpaste and Oral B Fluorinse mouthwash, and (5) MI Paste ONE toothpaste and Caphosol mouthwash. Microhardness, surface roughness values, and the topographical characteristics of the dentin surface were assessed. The highest percentage of recovered dentin microhardness (%RDMH) value was observed in groups 2 and 4, followed by groups 5 and 3, respectively. The %RDMH values in groups 2 and 4 did not demonstrate a significant difference (p = 0.855). The highest percentage of improvement in surface roughness was recorded in groups 2 and 4, with no significant differences (p = 0.989). The atomic force microscopy (AFM) findings were consistent with the surface roughness data. The best recovery of dentin microhardness and roughness were measured with the Elmex and Oral B toothpaste and mouthwash, followed by MI Paste ONE toothpaste and Caphosol mouthwash and Vitis anticaries biorepair toothpaste and mouthwash.

Background Socket preservation is a surgical procedure aimed at preserving the dimensions of the alveolar bone following tooth extraction. It is performed by filling the extraction socket with bone graft material with or without a barrier membrane. Recently, dentine obtained from extracted teeth has been tried as an autograft for socket preservation. Studies have compared the use of dentin to other bone grafts, however, systematic reviews evaluating the efficacy of dentin for socket preservation are limited. Hence, this systematic review protocol is proposed to generate evidence on the efficacy of dentin as a viable alternative to other bone graft materials for socket preservation. Methods This systematic review protocol was prepared according to the Methodological Expectations of the Cochrane Intervention Reviews (MECIR) guidelines. It will be conducted using the Cochrane Handbook for Systematic Review of Interventions. PubMed, Scopus, Web of Science, EMBASE, Epistemonikos, Cochrane Central, and EBSCO databases and clinical trial registries, will be searched for all randomized controlled trials (RCTs) and non-randomized studies that have used autologous dentin graft (either in particulate/putty, or/matrix form) for socket preservation. The radiographic and clinical assessment of bone and soft tissue healing of the preserved sockets along with patient-related outcomes following surgery will be assessed. The risk of bias assessment of the RCTs and Non-RCTs will be assessed using the ‘Cochrane Risk of Bias assessment tool (ROB II) and ROBINS-I respectively. The certainty of evidence will be assessed by the GRADE approach. Discussion This evidence is important for dental clinicians and the public to make an informed decision when choosing graft material for socket preservation. The extracted teeth are considered biological waste; however, this evidence provides scope for using a less invasive autograft for bone regenerative procedures. Systematic review registration PROSPERO: CRD42021201958 (Registered on 15/02/2021).

Over the last few decades, several new materials and techniques have been developed for bone regeneration. Scaffolds based on demineralized dentin matrix (DDM) present an attractive option due to their availability and several animal and human studies have been conducted to ascertain their utility in regenerative dentistry. The aim of this review was to summarize the recent studies conducted on DDM and used for bone grafts. PubMed, Web of Science, and Scopus were used to search for studies published within the last 10 years. The keywords and terms used were: “demineralized dentine matrix”, “bone grafting”, “bone augmentation” and “guided tissue regeneration” in various combinations. Original studies (in vitro, animal and human) and systematic reviews were included in the literature search. The literature search initially identified 23 studies (16 animal studies and 7 clinical reports. Most studies included in this review indicate that DDM has demonstrated promising results in a variety of dental and regenerative medicine applications. Further studies are required to completely comprehend its characteristics and prospective applications. Future studies should also focus on optimizing the processing protocols for the production of DDM-based scaffolds.

Background: Root dentin transparency, one of the age changes in dentin, is considered to be a stable parameter not affected by environmental and pathological factors. The effect of age changes in the transparency of root dentin in Nepalese population have not been established so far. In the present study, we aimed to determine the age of an individual using the root dentin transparency in the Nepalese subjects and attempt to derive the formula to estimate the age applicable to the Nepalese population. Materials and Methods: A cross sectional analytical study was conducted to measure the length of root dentin transparency in the tooth of patients of known age. Correlation of the age and the length of transparent root dentin was determined. A linear regression analysis was carried out to derive a formula applicable to the Nepalese population. Results: The length of transparent root dentin increased linearly with the age of an individual. The newly derived formula was used to calculate the estimated age from the length of transparent root dentin. The difference between the actual age and the calculated age was within 6 years in 63.2% of the sample. Conclusion: A simple and relatively inexpensive method for calculating age by measuring RDT is described.

Statement of the Problem: The prevalence of non-carious dentin lesions is on the rise mainly due to improved life expectancy. Successful management of these lesions is often challenging, and given that dentin can be remineralized, adverse consequences due to progression of these lesions can be prevented or minimized as such.Purpose: This study aimed to assess the effect of casein phosphopeptide amorphous calcium phosphate (CPP-ACP) and Remin-Pro remineralizing agents on dentin microhardness of non-carious dentin lesions.Materials and Method: This in vitro, experimental study evaluated 36 extracted sound human premolars. The teeth were decoronated at the cementoenamel junction. Enamel was removed, and dentin was exposed at the cervical third of the buccal surface. The primary microhardness of dentin was then measured. The teeth, standardized in terms of dentin microhardness, then underwent demineralization by acid etching and were subjected to microhardness test again. They were then randomized into three groups for treatment with CPP-ACP, Remin-Pro, and artificial saliva (control), and dentin microhardness was measured for the third time after treatment. Data were analyzed using ANOVA.Results: Within group comparisons showed a significant difference in microhardness at the three time points in all three groups (p< 0.005). Between-group comparisons revealed that the microhardness of the three groups was not significantly different at baseline or after demineralization. However, the microhardness of the three groups was significantly different after the intervention (p= 0.000). Pairwise comparisons revealed significantly higher microhardness in the CPP-ACP group than the other two groups (p= 0.003). Remin-Pro and the control groups were not significantly different in this respect (p= 0.340).Conclusion: CPP-ACP can be used for remineralization of non-caries dentin lesions; however, Remin-Pro does not appear to be effective for this purpose.

Background Socket preservation is a surgical procedure aimed at preserving the dimensions of the alveolar bone following tooth extraction. It is performed by filling the extraction socket with bone graft material with or without a barrier membrane. Recently, dentine obtained from extracted teeth has been tried as an autograft for socket preservation. Studies have compared the use of dentin to other bone grafts, however, systematic reviews evaluating the efficacy of dentin for socket preservation are limited. Hence, this systematic review protocol is proposed to generate evidence on the efficacy of dentin as a viable alternative to other bone graft materials for socket preservation. Methods This systematic review protocol was prepared according to the Methodological Expectations of the Cochrane Intervention Reviews (MECIR) guidelines. It will be conducted using the Cochrane Handbook for Systematic Review of Interventions. PubMed, Scopus, Web of Science, EMBASE, Epistemonikos, Cochrane Central, and EBSCO databases and clinical trial registries, will be searched for all randomized controlled trials (RCTs) and non-randomized studies that have used autologous dentin graft (either in particulate/putty, or/matrix form) for socket preservation. The radiographic and clinical assessment of bone and soft tissue healing of the preserved sockets along with patient-related outcomes following surgery will be assessed. The risk of bias assessment of the RCTs and Non-RCTs will be assessed using the ‘Cochrane Risk of Bias assessment tool (ROB II) and ROBINS-I respectively. The certainty of evidence will be assessed by the GRADE approach. Discussion This evidence is important for dental clinicians and the public to make an informed decision when choosing graft material for socket preservation. The extracted teeth are considered biological waste; however, this evidence provides scope for using a less invasive autograft for bone regenerative procedures. Systematic review registration PROSPERO: CRD42021201958 (Registered on 15/02/2021).

Statement of the Problem: It is stated that engine-driven instruments might cause dentinal defects during root canal preparation. These defects might spread and progress into greater fractures or vertical root fracture. Purpose: This study aimed to compare the incidence of dentinal defects that might arise all through preparation of root canals, using One Shape, RaCe, and WaveOne systems in canals with a curvature (0-20°) and (20-40°). Materials and Method: In this in vitro study, 150 mandibular first molars were enrolled. Based on the degree of curvature in the mesial roots, the samples were divided into two groups (n=75) of straight and moderately curved canals (0-20º), and severely curved canals (20-40°). Then each group was randomly divided into four sub-groups. In subgroups 1 to 3 from each group, canals were prepared using WaveOne, One Shape, and RaCe. Then all roots were sectioned at 3, 6 and 9-mm distances from the apex. The slices were evaluated using stereomicroscope at 12× magnification. The data were analyzed using the Chi-square and Fisher’s exact tests and the level of significance was set at 0.05. Results: Fracture and other defects were not found in the control groups. In canals with curvature (0-20°), WaveOne caused the maximum dentinal defects and RaCe produced the least. Moreover, in canals with curvature (20-40°), One Shape caused the maximum dentinal defects while WaveOne and RaCe caused equal dentinal defects approximately. Conclusion: There was a statistically significant relationship between the performance of RaCe and One Shape in canals with curvature (0-20º) and (20-40º), (p Value< 0.05) while no statistically significant difference was observed in connection to the performance of WaveOne (p> 0.05).

Objective This ex vivo study evaluated the effect of ultrasound and Er:YAG laser irrigation activation techniques on the penetration of sodium hypochlorite solution into infected human root canal dentin, providing a reference for clinical infection control of infected root canals. Methods Thirty-six cases of infected root canals were collected and randomly divided into three groups according to the irrigation technique: 12 cases in the conventional syringe irrigation (CSI) group, 12 cases in the passive ultrasonic irrigation (PUI) group, 12 cases in the Er:YAG laser and photon-induced photoacoustic streaming (PIPS) group and 36 cases of clean root canals (12 cases in the CSI group, 12 cases in the PUI group, 12 cases in the PIPS group). All of the selected root canals were straight root canals of posterior teeth. After standardizing the root length, all canals were subjected to instrumentation and dynamic irrigation. 2% methylene blue solution was used to visualize the penetration of the irrigant. EXAKT cutting and grinding equipment was used to take transverse sections of 100-150 μm at the coronal, middle and apical thirds of the root canals. The data (maximum penetration depth, average penetration depth, and penetration percentage) were observed under a light microscope to evaluate the effect of dye penetration. Results With the three irrigation techniques, the maximum penetration depth, average penetration depth and penetration percentage of the infected root canals were significantly lower than those of clean root canals in the full length of the root canal (P0.05). There was also no significant difference in the maximum penetration depth, average penetration depth or penetration percentage between the PIPS and PUI groups (P>0.05). Conclusion The dentine permeability of infected root canals was weaker than that of clean root canals. Er:YAG laser-assisted irrigation activation technology could significantly improve the penetration of sodium hypochlorite solution into infected dentin, but passive ultrasonic irrigation did not significantly improve the penetration.

Objective To explore the influence of a contracted endodontic access cavity on the risk of canal transportation in the danger zone of the mesial root canal of mandibular first molars (MFMs) using a one-curve preparation system, and to provide an experimental basis for the clinical selection of a better pulp approach. Methods Twenty MFMs extracted for severe periodontal disease that met the inclusion criteria, including intact coronal roots, mesial roots with two separate root canals, mesiobuccal canal (MB) and mesiolingual canal (ML), and a curvature of 0° to 20°, were selected. Subsequently, these MFMs were randomly divided into two groups based on the endodontic access design, including the traditional endodontic access cavity (TEC) group and the contracted endodontic access cavity (CEC) group. In the TEC group, the pulp chamber roof of the tooth was completely removed, while in the CEC group, the pulp chamber roof and peri-cervical dentin were preserved as much as possible. Then, the One Curve single file was adopted to conduct root canal preparation. Next, cone beam computed tomography (CBCT) was performed on extracted teeth before and after preparation, and the measurement sections were located at 0-7.0 mm below the root bifurcation of the mesial root canal at 1 mm intervals. The minimum wall thickness on the mesial and distal aspect of the root canal was measured in each section. Results ① Prepreparation CT measurements of 20 MFMs showed that the danger zone in the range 0-4 mm under root bifurcation, a mean thickness of 1.18 mm on the mesial aspect of the MB root canal and 1.08 mm on the distal aspect. The mean thickness of the ML root canal was 1.28 mm on the mesial aspect and 1.07 mm on the distal aspect. ② Compared with that of the traditional endodontic access cavity, no significant difference in the decrease of wall thickness was observed in the danger zone of mesial root canal of MFMs in the contracted endodontic access cavity (t = 1.319，P = 0.19). ③ In the mesiobuccal canal, compared with the apical transportation of the traditional endodontic access cavity, which tends to be more mesial side, the apical transportation of contracted endodontic access cavity tends to the distal side. In the mesiolingual canal, both apical transportation groups tended to be on the distal side. Conclusion When using the One Curve file, compared with traditional endodontic access, the contracted endodontic access cavity based on the minimally invasive concept does not increase the risk that the mesial root canal of mandibular first molars is transported.

In cases of unsuccessful endodontic treatment, E. faecalis is commonly detected and remains popular among the scientific community for in vitro and in vivo research. The nature of the bacteria's predominance is dependent on the difficulty in cleaning the apical portion of the tooth and E. faecalis' capacity to grow deep into the dentinal tubules. The purpose of this review is to gather current research on root canal disinfection against E. faecalis. In this literature review, four databases were searched: PubMed, EBSCOhost, ScienceDirect, and Google Scholar, with explicit inclusion and exclusion criteria. The compiled review shows that a predominant multi-microbial community within a persistent root canal infection include Porphyromonas gingivalis, Fusobacterium nucleatum, and Enterococcus faecalis. E. faecalis produces moderate biofilms and causes infection through its virulence factors such as esp, cylA, ace, gelE, asa, and efaA. Several disinfecting agents and approaches have been explored for their capacity to eradicate E. faecalis and penetrate the dentinal tubules. Sodium hypochlorite (NaOCl) and chlorhexidine (CHX) gel eliminate E. faecalis and other resistant microbes such as Staphylococcus aureus, and Escherichia coli. Combing NaOCl irrigation with the following: Photon-induced photoacoustic streaming, passive ultrasonic irrigation, and diode laser irradiation, eradicates E. faecalis. The current research has shifted towards nanoparticles against E. faecalis because of its dissolution capacity, size, and antimicrobial efficacy. E. faecalis resists calcium hydroxide through its proton pump mechanism, but it is susceptible to Ca(OH)2 when applying a proton pump inhibitor or chlorhexidine. [Med-Science 2023; 12(2.000): 606-12]

Background and Objective: Due to the importance of primary anterior teeth in chewing, pronunciation of words, self-confidence, facial appearance of children, efforts to preserve these teeth continue. The aim of the present study was to evaluate the push-out bond strength of 5th, 6th, 7th, and 8th generation bonding agents to intracanal dentin of primary anterior teeth which are reconstructed with the composite posts. Methods: The present experimental in vitro study was conducted on 60 extracted primary anterior teeth with at least two-thirds of the root length remaining. The teeth were randomly divided into five groups: 5th generation (3M Adper single bond 2 Adhesive-USA), 6th generation (clearfil SE bond, Japan), 7th generation (kerr-optibond all in one Adhesive-Italy), and 8th generation total-etch and 8th generation self-etch (GC-G permio bond-Japan) bonding agents. After root canal preparation, prepared canals were filled with Metapex. The coronal 3mm of the canals was etched and impregnated with the dentin bonding agents. Then, they were restored with composite. The push-out test was performed to evaluate the bond strength of adhesives. Accordingly, by a light microscope the failure modes were determined. Findings: The mean bond strength of 5th, 6th, 7th, and 8th generation (self-etch, total-etch) bonding agents was 4.36±2.15, 3.88±1.55, 4.29±2.02, 12.84±3.62, and 7.77±3.81 MPa, respectively. The push-out bond strength of the 8th generation bonding agent using both self-etch (p=0.000) and total-etch techniques was higher than the 5th, 6th, and 7th generation bonding agents (p=0.032, 0.01, 0.027, respectively). No significant difference was found between the bond strength of the 5th, 6th, and 7th generation bonding agents. Conclusion: The push-out bond strength of the 8th generation bonding system was higher than the other groups. Therefore, the 8th generation bonding agents can be used to bond composite posts to intracanal dentin of primary anterior teeth. Also, self-etch (8th generation) has higher bond strength compared to the total-etch technique.

Backround: In this study, we aimed to investigate the effect of dentin matrix proteins on the differentiation of guinea pig dental pulp stem cells to regenerate Dentin Bridge. Materials and Methods: This experimental study was performed on six adult male guinea pigs. Pig incisor teeth were divided into two groups: the first group was induced by calcium hydroxide as a control group and the second group was induced by matrix protein induction as a case group. After 1 and 3 days, the samples of both groups were stained by hematoxylin and eosin to examine the presence of odontoblast-like cells, the severity of inflammation, and the type and amount of dentin which was made, microscopically and for counting stem cells in the dentin site. Immunohistochemistry staining method was done. Results: In the case group, the amount of reconstituted dentin, the presence of stem cells and odontoblastic differentiation were higher than in the control group (P < 0.05) and the type of regenerated dentin potentially was of higher quality, although it was not statistically significant (P = 0.924). However, the amount of regenerated dentin (P = 0.001), the presence of pulp stem cells (P = 0.001) and the increased quality of regenerated dentin (P = 0.001) in both groups on the 1st and 3rd days were significantly different. Conclusion: The results showed that dentin matrix proteins were more effective on stem cell migration, odontoblastic differentiation, amount and quality of restorative dentin than the control group, but did not significantly; probably because low sample size.

Objective To study the effect of nonthermal argon atmospheric pressure plasma (NTAPP) treatment on the bonding strength between dentine and self-etch adhesive and the wettability of dentine surfaces under different treatment times. Methods The plasma jet was operated at an input power of 9 W. Argon was used as the operating gas at a flow rate of 5 L/min. The dentin surface was exposed to the plasma jet (n=6) for various times (0, 5, 10, 15, 20 s). After a one-step self-etch adhesive (S3 Bond) was applied to the treated dentine surface, microtensile bonding specimens were made, and the microtensile bonding strength was tested. Then, the dentine surface contact angles were measured after NTAPP treatment for 5, 10, 15, and 20 s with the same gas flow rate and input power described above. Results Along with the NTAPP treatment time, the dentin immediate bonding strength was significantly increased. The 15 s group showed significantly elevated bonding strength (31.82±2.80 MPa) in contrast to the other groups. The contact angles of each experimental group significantly decreased compared with the contact angles of the negative control group (75.57°±1.45°). The contact angles decreased the most to 33.56°±2.14° with NTAPP treatment for 15 s, and its wettability was the highest. Conclusion NTAPP treatment can significantly increase the wettability of the dentin surface and improve the adhesive strength of the adhesive interface with self-etching adhesive, which is also related to the treatment time.

This study aimed at comparing shear-bond strength (SBS) of different self-etching adhesive systems (Clearfil S3 Bond Plus, G-Premio BOND and IBond) to dentin without or with diode-laser irradiation before photo-polymerization and to determine the effect of storage and thermo-cycling on SBS of adhesive systems. Methods: The buccal surface of 84 extracted maxillary premolars was grounded to create flat surface. The specimens were allocated into 3 groups (n = 28) depending upon the adhesive systems, then each group was divided into two sub-group (I, II) (n = 14). After the placement of respective adhesive systems on the flat surface, adhesive system in group I was photo-polymerized immediately, while in group II, the adhesive systems were exposed to diode-laser before photo-polymerization. Composite cylinder (4 mm in diameter and 2 mm height) was built on the flat surface of each specimen. Then group I and II were divided into two sub-groups (n = 7) according to the storage time and thermo-cycling (1 day without thermo-cycling or 72 days with thermo-cycling) then all the specimens were stored in distilled water. The SBS was measured at the end of storage period. ANOVA, Duncan’s Multiple Range Test and independent t-test “P ≤ 0.05” were used for data analysis. Results: G-premio BOND showed the highest mean value of SBS followed by Clearfil S3 Bond plus without significant difference between them, while IBond revealed the least mean value. Laser irradiation had positive effect on the bond-strength of all tested adhesive systems. The results also showed that the storage with thermo-cycling had negative effect on the bond-strength in groups without laser irradiation for all tested adhesive systems, while for groups with laser irradiation, the reduction in the bond-strength of all tested adhesive systems was not significant. Conclusion: Diode-laser application prior to photo-polymerization of self-etch adhesive systems significantly increased the bond-strength to dentin and can increase the durability of composite adhesion.

Dental and craniofacial bone development is a highly coordinated process that is tightly controlled by genetics and influenced by complex environments. The abnormal regulation of many development-related signaling molecules may lead to abnormal tooth development, severe craniofacial bone formation disorders, and developmental deformities. Transforming growth factor-β (TGF-β) is widely expressed in vivo and participates in many cellular biological processes, showing complex regulatory roles in mammalian craniofacial bone growth and tooth development. In tooth development, abnormal TGF-β signaling can lead to the failure of tooth germ formation, and its deletion mutation can directly affect odontoblast differentiation and enamel formation defects. However, the current research on TGF-β mainly focuses on the early stage of tooth development, and a comprehensive and systematic study of TGF-β-related tooth development is lacking. TGF-β signal transduction mainly controls the development of teeth and craniofacial bone by regulating the expression of development-related molecules via the classical Smad-dependent signaling pathway. In addition, the nonclassical mitogen-activated protein kinase (MAPK) pathway also participates in this process. Abnormal TGF-β signaling may cause jaw development disorders, temporomandibular joint dysplasia and inflammation, and cleft palate. Because the specific regulatory mechanism of TGF-β in craniofacial bone development has not been fully elucidated, its specific application in the treatment of related diseases is also greatly limited. This paper describes the new research progress of TGF-β in the development of teeth, jaws, temporomandibular joints and palate as well as related diseases.

Statement of the Problem: The success of root canal therapy depends on root canal irrigation, disinfection, and sealing of root canal. Wettability and roughness of root dentine surface are important factors in root canal disinfection and sealing.Purpose: This study aimed to assess the effect of chloroform application on roughness and wettability of the root canal walls in endodontic retreatment.Materials and Method: This in vitro experimental study evaluated 70 sound extracted human anterior teeth. The specimens were then randomly assigned to 7 groups as follows: Chloroform (group 1), 1g gutta percha+chloroform (group 2), 2g gutta percha+ chloroform (group 3), 1g gutta percha+ 1g sealer+ chloroform (group 4), 2g gutta perch+ 2g sealer+chloroform (group 5), 1g sealer + chloroform (group 6) and 2g sealer + chloroform (group 7). One drop of distilled water was placed on each tooth to measure the contact angle and wettability. Photographs were obtained of an area measuring 50×50 µm2 in three directions under an atomic force microscope to measure the roughness. The tooth blocks were exposed to the abovementioned mixtures for 10 min, and then rinsed with saline. The roughness and wettability of each sample were measured before and after treatment. Data was analyzed using one-way ANOVA and Tukey’s test.Results: The roughness of all groups significantly decreased following treatment, except for groups 1 and 4. The contact angle increased in all groups after treatment (except for the chloroform group), which indicated decreased wettability. The roughness and the contact angle have shown no correlation.Conclusion: Application of chloroform for removal of gutta-percha and sealer in endodontic retreatment decreases the roughness and wettability of dentine.

Background: Endodontic shaping causes stress and strain in the root canal dentin. Dentin microcracks have the potential to be later followed by root fractures occurring under the occlusal load. The aim of our research was to theoretically determine the values of such dentinal states of stress and strain during the endodontic shaping of curved root canals using finite element analysis (FEA). Methods: To highlight the stress concentrations in dentin, two geometric models were created considering the volume of the curved dental root and the contact between the endodontic file and the root canal walls. The application of forces with different values was simulated both on a uniform curved root canal and on a root canal with an apical third curvature of 25° as they would be applied during the preparation of a root canal. Results: In the case of the first model, which was acted upon with a force of 5 N, the deformations of the root canal appeared along the entire working length, reaching the highest values in the apical third of the root, although there were no geometric changes in the shape of the root canal. Regarding the second root model, with an apical third curvature of 25°, although the applied force was 2 N, the deformations were accompanied by geometric changes in the shape of the root, especially in the upper part of the apical third. At a higher force of 7 N exerted on the endodontic file, the geometric shape changed, and the deformation reached extreme critical values. The resulting tensile stresses appearing in the experimental structure varied similarly to the deformations. Conclusions: Significant stress and strain can develop, especially in the apical third of curved root canals during their shaping, and the risk of cracks is higher for endodontically treated teeth presenting severe curvatures in the apical third of the root.

Objective: Overview of the updated literature on the classification of adhesives systems and CAD/CAM materials with clinical guidelines to condition various surfaces for bonding to the tooth structure. Data sources: Searches were conducted in MEDLINE, EMBASE, PubMed, Web of Science, Scopus, Cochrane Library, and Google Scholar using specific keywords. Results: 240 papers were revised, 150 articles were excluded, and 90 were eligible for the review. Most studies concluded the essentiality of bonding E-max, zirconia, and hybrid materials to enhance fracture toughness and fatigue resistance. The success of ceramic bonding depends on the microstructure and surface treatment of the materials. The proper treatment of the intaglio starts with using alumina oxide or hydrofluoric acid. This initial treatment could be followed by monobond salinization, which improves the chemical adhesion. Zirconia-based ceramics have grown lately and become the most prescribed for posterior and anterior teeth. Zirconia can be bonded to the tooth structure using the APC concept and 10 MDP promoting primers. Three hundred adhesive resin systems are currently available in the market, and each is different in chemical composition and clinical bonding strength. Of the three hundred systems, the total-etch system remains the gold standard, especially on the enamel surface. The self-etch adhesive system is favorable on dentin due to lowering the postoperative sensitivity. A new generation of dentin adhesives, called universal or multi-mode adhesives. This system has become popular and can be used either as etch-and-rinse or self-etch adhesives. Conclusion: The chemistry of adhesive systems has changed across generations. The variation of dental tissue is the decisive factor in selecting adhesive systems, resin cement, and ceramic materials. Moreover, a reliable bonding strength necessitates a perfect surface treatment and bonding promoter for tooth and CAD/CAM materials.

Universal adhesives have been widely used in dentistry due to their easy application process and wide range of applications. In the literature, the etching modes of universal adhesives, coating methods of universal adhesives, pretreatment of adhesive, and other factors were reported to have an impact on the bonding performance of universal adhesives. This review focused on the factors affecting the bonding performance of universal adhesives and aimed to provide evidence-based recommendations for clinical practice. Current research suggests that the etch-and-rinse mode can achieve a better adhesive strength of enamel and that the etch-and-rinse mode and the self-etch mode exhibit a similar adhesive performance in bonding dentin. The bond strength would be improved by prolonging the application time, applying a double layer of adhesives, and wetting enamel and dentin with water or ethanol before adhesive procedures. Chlorohexidine (0.2%) and metal nanoparticles can inhibit matrix metalloproteinases (MMPs) and improve the long-term bond strength of dentin. Finally, universal adhesives have excellent stability and saliva pollution resistance, although they lack blood pollution resistance. In the clinic, dentists should pay attention to the etching modes of universal adhesives, coating methods of universal adhesives, pretreatment of adhesive, and other factors that may affect the effect strength. universal adhesives will be improved in bonding strength of enamel in self-etch mode and bonding performance in demineralized dentals around caries.

The study evaluates the influence of irrigation with sodium hypochlorite on the microtensile bond strength to dentin with different bonding protocols on pre-endodontic restorations. After endodontic opening of restored human molars, teeth were randomly divided into four experimental groups: group 1 was not irrigated and the access was restored, while the other groups were irrigated with sodium hypochlorite. Group 2 was restored, group 3 had the endodontic access walls instrumented, and group 4 had CoJet sandblasting and silane application prior to final restoration. The bond strength after irrigation showed higher values when silicatization is performed.

Statement of the Problem: The success of dental restorations depends mainly on its ability to bond to dental structures and resist the multitude of forces acting on it within the oral cavity. Purpose: Therefore, the aim of this study was to evaluate the shear bond strength (SBS) of three different glass ionomer based restorative materials. Materials and Method: In this in vitro analytical study, 30 intact primary molars were sectioned buccolingually to obtain 60 sections. These sections were embedded in auto polymerizing acrylic resin and polished to obtain a flat dentin surface. Restoration cylinders were built on the dentin surface with the help of a Teflon template called bonding jig. Each group (n= 20) was restored as group A with conventional glass ionomer cement (GIC) (GC Fuji Gold Label Type 9), group B with Bioactive restorative material (ACTIVATM KIDS BioACTIVE Restorative material), and group C with Zirconia reinforced glass ionomer cement (Zirconomer). Following restoration, SBS testing was performed using Universal Testing Machine. The data obtained were statistically analyzed using One way ANOVA test and post hoc Tukey test (p= 0.05). Results: The SBS values were significantly greater in the ACTIVA KIDS group as compared to the other two groups (p< 0.05). There was no significant difference in the SBS values between group B and group C (p> 0.05). Conclusion: The SBS of the ACTIVA KIDS to primary teeth dentin was the highest as compared to Zirconomer and conventional GIC. Therefore ACTIVA KIDS may protect primary teeth against recurrent caries and failure of the restoration.

Purpose: To evaluate the push-out bond strength (PBS) and failure mode of single adjustable (SAP) and customized (CP) posts cemented to root canal dentin using conventional (RelyX Ultimate) or self-adhesive (RelyX U200) dual-cure resin cements. Methods: Herein, 40 bovine mandibular incisors were divided into four groups (n = 10): SAP cemented with RelyX Ultimate (SAP-UT), SAP cemented with RelyX U200 (SAP-U2), CP cemented with RelyX Ultimate (CP-UT), and CP cemented with RelyX U200 (CP-U2). PBS and failure modes were analyzed. Three-way repeated measures ANOVA test followed by Tukey’s test and Fisher–Freeman–Halton exact test were used for data analysis (α = 5%). Results: The PBS values for SAP (p .05). When conventional resin cement was used, the SAP showed significant differences compared to CP (p

The purpose of this study was to evaluate in vitro the efficacy of alumina, sodium bicarbonate and erythritol-based tooth air-abrasion on shear bond strength (SBS) of resin composite to dentin. Methods and Results: In order to assess the strength of the adhesive bond of the resin composite to tooth dentin, 50 tooth samples were prepared in accordance with the Ultradent Shear Bond Test method. All samples were divided into 5 groups. In Group 1 (n=10) and Group 2 (n=10), for air-abrasion of dentin surface 2 powders based on aluminum oxide with a particle size of 50μm and 27μm, respectively, were used (RONDOflex plus 360, KaVo, Biberach, Germany). In Group 3 (n=10) and Group 4 (n=10), other abrasive powders based on sodium bicarbonate (40μm) and erythritol (14μm), respectively, were used for a similar purpose (Air-Flow Classic comfort, Air-Flow Plus, EMS, Nyon, Switzerland). The control group (n=10) consisted of the remaining tooth samples in which the dentin surface, after preparation with a carbide bur, was not subjected to an air-abrasion.The one-day adhesive strength of bonded interfaces was evaluated on an UltraTester device (Ultradent Products Inc., USA) after resin bonding without aging simulation. The speed of movement of the test clamp with the installed sample was set to 1 mm/min. The maximal value of bonding failure was fixed in pounds (lb). The dentin surface ultrastructure was studied on 10 additional tooth samples, which were prepared for SEM analysis. It was found that the treatment of dentin surface with air-abrasive powders based on alumina (50 μm and 27 μm) and sodium bicarbonate (40 μm) did not improve the strength of the adhesive bond of resin composite to dentin. The strength of adhesion of the resin composite to dentin decreased significantly after air-abrasion of the tooth surface with erythritol-based powder.

Aim: Lyophilized demineralized dentin matrix (LDDM) consists of a type 1 collagen complex matrix containing growth factors and no mineral crystals. Although the efficacy of LDDM for bone grafting is well known, there is limited evidence on the biological response to human lyophilized DDM. Therefore, the aim of this study was to evaluate the biological response of subcutaneous tissues in rats to powdered LDDM, mineral trioxide aggregate (MTA), and Biodentine implanted using polyethylene tubes. Methods: Forty Wistar rats were divided into four groups (n = 10 each) depending on the experimental time intervals and were placed in polyethylene tubes containing LDDM, MTA, biodentine, and one empty control. After 3, 7, 15, and 30 observation days, the animals were sacrificed and quantitative and qualitative analysis of the subcutaneous tissue samples was carried out. The intensity of the inflammatory response was scored from 0 (no response) to 3 (severe response), and the data were statistically analyzed using ANOVA and Bonferroni tests (p

Purpose This study evaluated the combined effects of Carbodiimide (EDC) and ethanol–wet bonding (EWB) pretreatment on the bond strength and resin–dentin surface. Methods Phosphoric acid-etched dentin specimens were randomly divided into five groups based on the following pretreatments: deionized water (control), EWB, 0.3M EDC in water (EDCw), EDC water solution combined EWB (EDCw + EWB), and 0.3M EDC in ethanol (EDCe). A scanning electron microscope (SEM) was used to observe the morphology of collagen fibrils on the demineralized dentin matrix in each group after pretreatment. The adhesives Prime & Bond NT (PB) (Dentsply De trey, Konstanz, Germany) or Single bond 2 (SB) (3M ESPE, St. Paul, MN, USA) was applied after pretreatments, and a confocal laser scanning microscope (CLSM) was used to evaluate the quality of resin tags. The degree of conversion (DC) of the adhesive was investigated by Fourier transform infrared spectroscopy (ATR-FTIR). The dentin was first bonded with resin and bathed in water at 37 °C for 24 h. Half of them were subjected to 10, 000 cycles in a thermocycler between 5 °C and 55 °C before a microshear bond strength (µSBS) test. The statistical methods were Analysis of Variance (ANOVA) and a Tukey post hoc test at α = 0.05. Results The µSBS was significantly affected by pretreatments (p

Dental pulp is a vital organ of a tooth fully protected by enamel and dentin. When the pulp is exposed due to cariogenic or iatrogenic injuries, it is often capped with biocompatible materials in order to expedite pulpal wound healing. The ultimate goal is to regenerate reparative dentin, a physical barrier that functions as a "biological seal" and protects the underlying pulp tissue. Although this direct pulp-capping procedure has long been used in dentistry, the underlying molecular mechanism of pulpal wound healing and reparative dentin formation is still poorly understood. To induce reparative dentin, pulp capping has been performed experimentally in large animals, but less so in mice, presumably due to their small sizes and the ensuing technical difficulties. Here, we present a detailed, step-by-step method of performing a pulp-capping procedure in mice, including the preparation of a Class-I-like cavity, the placement of pulp-capping materials, and the restoration procedure using dental composite. Our pulp-capping mouse model will be instrumental in investigating the fundamental molecular mechanisms of pulpal wound healing in the context of reparative dentin in vivo by enabling the use of transgenic or knockout mice that are widely available in the research community.

Objective To study the effects of different concentrated sulfuric acid etching durations on the shear bond strength between polyether-ketone-ketone (PEKK) and dentin, providing a scientific basis for the clinical bonding procedures of PEKK prosthesis. Methods Forty-four PEKK specimens were prepared and randomly divided into four groups: group A was the control group, which was only polished with abrasive papers, group B, group C and group D were experimental groups, which were etched by 98% concentrated sulfuric acid for 5 s, 30 s and 60 s, respectively. In addition, one sample was randomly selected from each group, and the profile was prepared by a slow cutting machine. The surface morphology of the profile was observed under SEM. After the four groups of specimens and dentin were bonded by resin, they were soaked in distilled water at 37 ℃ for 24 h. After the shear bonding strengths were measured, the fracture interfaces of the specimens were examined by the scanning electron microscopy and stereomicroscopy, and failure models of bonding were analyzed. Results After acid etching treatments, the cross-sectional images in group B presented uniform spongy shapes, while the cross-sectional images in group C and group D showed destructive pore structures. The shear bond strengths of group B (16.84 ± 1.84) MPa, group C (12.33 ± 1.22) MPa and group D (6.44 ± 1.18) MPa were higher than that of group A (3.99 ± 1.06) MPa (P < 0.05). The highest shear bond strength was observed in group B (16.84 ± 1.84) MPa. Conclusion The surface treatment of 98% sulfuric acid etching for 5 s manifested the best bond strength between PEKK and dentin.

The number of drug addicts in the world is growing every year. The aim of the study was to assess the dental status of drug-addicted patients with parafunction of the dental-jaw apparatus. We used clinical, analytical, functional and histological research methods. 119 drug-addicted and 110 non-drug-dependent patients aged 18 to 54 were examined. In order to confirm the presence of parafunctions of the dental-jaw apparatus in patients, we conducted an occludogram study, as well as an assessment of the index of parafunctions of the masticatory muscles and the degree of their severity. The structure of tooth tissues was examined by histological method. Examination of drug-addicted patients revealed the presence of numerous carious cavities, secondary adentia, enamel erosion, pathological abrasion, signs of gingivitis and periodontitis, tooth chipping. The prevalence of parafunction of the dental-jaw apparatus, in particular bruxism, in drug-addicted patients is 1.56 times higher than this figure among non-drug addicts. The results of the occludogram and the index of parafunctions of the masticatory muscles differ significantly between the study groups. The mean value of the masticatory muscle parafunction index among drug-addicted patients is 2.06 times significantly higher than the value among non-drug-addicted men and 2.03 times higher among women. Histological examination of the tooth tissues of drug-addicted patients indicates a disorder of the mineralization of both enamel and dentin. Thinning of the peripheral zone of the pulp, which is normally represented by a layer of odontoblasts, which provide regeneration and nutrition of dentin, is more common in persons under 25 years of age. Drug use adversely affects the dental status of patients and the condition of the hard tissues of the tooth.

Resin-modified glass ionomer cement (RMGIC) has good physical, chemical and biological properties and is suitable for the treatment of deciduous caries, aged root surface caries and wedge-shaped defects. Surface treatment is a common method to improve bonding strength, which can improve physical and chemical retention between different components. This paper mainly introduces the current research status of the influence of different dentin surface treatment methods on the bonding strength of RMGIC. At present, the common dentin surface treatment methods are pretreatment, acid etching, laser treatment, etc. The pretreatment agent can improve the bond strength of RMGIC by increasing the surface area and porosity of dentin. The bond strength of RMGIC could be effectively improved after the dentin was treated by an acid-etching bonding system. The dentin was treated with a laser to obtain a higher bonding strength. However, whether the use of resin adhesives will affect the release of fluoride ions in RMGIC into the deep dentin and thus affect the repair effect also needs further research.

The objective of this study was to compare the ability of different endodontic irrigation activation methods to enable irrigant penetration, remove the smear layer from root canal walls after preparation, and investigate surface effects on dentine. Root canals of 90 single-rooted teeth were prepared and irrigated with EDTA (17%) and sodium hypochlorite (5%), where both irrigants or sodium hypochlorite only were activated as follows: conventional needle irrigation, ultrasonic activation, sonic activation (EDDY), or laser-based activation (photon-induced photoacoustic streaming/PIPS). For the evaluation of irrigant penetration into dentinal tubules, methylene blue was injected and activated as well. Subsequently, teeth were sectioned horizontally, and dye penetration depths were measured. Alternating sections were split in halves and randomly selected for scanning electron microscopic analysis. Root canal dentine was assessed for smear layer removal and surface disintegration according to a defined scoring system. The data were analyzed statistically with nonparametric and chi-squared tests for whole teeth and separately for coronal, middle, and apical thirds. All the tested activation methods removed a thicker smear layer than needle irrigation only. Additional activation of EDTA improved penetration depths of the irrigants, but not the smear layer removal. Surface disintegration of root canal dentine was observed with the additional activation of EDTA and particularly after laser-based techniques. Additional activation of EDTA does not seem to offer any convincing advantages in terms of irrigant penetration or smear layer removal but disrupts the dentine surface. Especially laser-based activation resulted in undesirable destruction of root canal wall dentine.

Previous research states that adding propolis to powdered dental materials can increase the mechanical strength of the material. To analyze the differences and correlation of dentin elastic moduli and pH value after the exposure of calcium hydroxide, a mixture of propolis and calcium hydroxide, also a mixture of propylene glycol (PG), calcium hydroxide, and propolis. The dentine of bovine incisors was exposed into various compositions of a mixture of propolis, PG, and calcium hydroxide. The measurement of pH value and dentin elasstic moduli was performed after 7 days. To find difference among groups, one-way ANOVA was used, and Honestly significant difference (HSD) Tukey to compare each groups, followed by Pearson to define the correlation. A statistically meaningful difference was recorded between the groups (P < 0.05), and there was correlation between dentin elastic moduli and pH value. The more alkaline the environment, the more rigid the dentin. [ABSTRACT FROM AUTHOR]

The concept of “minimally invasive dentistry” aims to provide conservative treatment of cavities in which sound dentin is removed. Because the Er: YAG laser can selectively remove caries, the smear layer is removed, dentin tubules are exposed after the preparation of substrate conditioning, and its advantages of precision, safety and painlessness are deeply valued. At the same time, the bonding strength between the prepared dentin surface and the filling material is different due to the different parameters of the Er: YAG laser. In this paper, the principle of dentin bonding, the mechanism of Er: YAG laser action, after treatment of dentin with different parameters (power, energy density, pulse duration, and irradiation distance), whether there is thermal damage to pulp tissue, the ultramicro morphology of dentin surface, the bonding properties of different bonding systems and the filling materials between irradiated hard tissues were reviewed. An appropriate parameter range (power ≤ 10 Hz, energy density ≤ 60 mJ, and pulse duration ≤ 50 μs) combined with water spray cooling will not cause thermal damage to the pulp tissue, while the higher power, energy density and pulse duration of laser treatment for dentin will lead to melting, carbonization, cracks, narrowing of the gap between collagen fibers, etc., which will limit the penetration of adhesives and have a negative impact on bonding. However, whether the adhesive systems based on the smear layer are suitable for dentin after laser treatment needs to be further explored.

The failure or delayed healing process may have occurred in critical size defect condition. Non-osteogenic cell migration in critical size defect can be prevented by aapplication of a guided bone regeneration (GBR). GBR may serve as osteoinductive biomaterial, one of example of GBR is dentine bovine. Demineralized Dentine Material Membrane (DDMM) can be obtained from bovine dentine as GBR. Thus, the aim of this study is to investigate the Demineralized Dentine Membrane Material (DDMM) as a Guided Bone Regeneration (GBR) effect on foreign body giant cell. The sample consisted of sixty, 2-3 months old male rats of Wistar rats (Rattus novergicus) with 250-300 grams body weight. The samples were divided into two control groups (K) and three treatment groups (P). Mandibular bone defect with sized 5 x 5 mm in group K(-) was not applied with GBR membrane, while Group K(+) was applied with Bovine Pericardium Collagen Membrane (BPCM). In the treatment groups, DDMM was applied in Group P1, DDMM and grafts were applied in Group P2, BPCM and grafts were induced in Group P3. Six samples were sacrificed on Day 3 and 7 post-operation for the histology examination using Hematoxylin Eosin (HE) staining. Foreign body giant cells counts were examined and statistically analyzed using an independent t-test (p<0.05). As the results, there was no significant difference in the amount of giant cell in every groups on Day 3 and 7. Meanwhile, DDMM showed the comparable effect on giant cell of mandibular critical size defect to BPCM. In conclusion, indeed, the implantation of DDMM has potential for being used as an alternative membrane for absorbable guided bone regeneration biomaterial. [ABSTRACT FROM AUTHOR]

In recent years, due to precise control of the amorphous mineral precursor in the demineralization of dentine collagen fibers in orderly deposition, forming apatite crystals similar to the natural mineralized dentin, the bottom-up remineralization approach which does not depend on the existence of seed crystallites, dentin biomimetic mineralization techniques gradually become a hotspot in the research field of restoration of demineralized dentin caused by dental caries. This paper reviews the changing concepts and practices of the remineralization of demineralized dentin, emphasizing biomimetic remineralization studies. The results of the literature review show that the traditional dentin remineralization method is usually a disordered mixture of demineralized dentin and minerals, so mineralized dentin is not comparable to natural mineralized dentin in terms of the morphological characteristics and mechanical properties. With its gradual increase in recent years, dentine biomimetic mineralization technology perfectly resembles the minerals in the dentin overlapping sequence arranged with the dentine collagen fiber structure characteristics, leading to greatly improved microstructural, physical and chemical properties. As a result, dentine biomimetic mineralization technology is expected to achieve new breakthroughs in the fields of resin-dentin bonding mixing layers and the decay of dentin. At present, the technical obstacles that need to be overcome in the clinical application of the biomimetic remineralization of dentin are how to continuously supplement all the active ingredients needed for mineralization in the process of remineralization and how to keep the mechanical properties of the parent material unchanged while slowly releasing all ingredients. Researchers have successively proposed three-step transportation of the biomimetic remineralization of raw materials, as well as the preparation of mineralization precursors stabilized by polymers in advance and the reuse of mesoporous silicon nanomaterials for the transportation of the mineralized ingredient system. The concept described above provides the preliminary in vitro experimental basis for the transformation of the biomimetic remineralization strategy of dentin in clinical applications.

Background and aim: Maxillary first molars exhibit a variety of anatomies in the mesiobuccal root, with a concave distal root that limits the preparation of the canal to prevent strip perforation. The purpose of this study was to evaluate the dentin thickness around the second mesiobuccal canal (MB2) in maxillary first molar using cone beam computed tomography (CBCT). Materials and methods: The present retrospective descriptive cross-sectional study was conducted on 120 CBCT images of patients referred to Radiology Centers of Urmia (Iran) between 2017 and 2019. The first and second mesiobuccal canals (MB1 and MB2) were both detected and the dentin thickness around the MB2 canal in the mesial, distal, and palatal surfaces and its distance to MB1 at three cross-sections were evaluated by two endodontists. Results: In all three sections the lowest dentin thickness was in distal wall, and the highest was in palatal wall; this difference was statistically significant at all sections (p Conclusion:The small thickness of distal indicates more conservative considerations in endodontic and prostodontic treatments . The CBCT seems to be an effective and noninvasive method in examining root and canal morphology and may be used as a preoperative radiography to assess the dentin thickness in danger zones to prevent iatrogenic errors.

Statement of the Problem: Low pH of self-etch adhesives might cause suboptimal polymerization. Purpose: This study aimed to evaluate the effect of dentin depth (deep and superficial) on polymerization efficacy of two self-etch adhesives, with different pH by means of Knoop hardness test. Materials and Method: In this in vitro study, sixty sound molars were used to prepare 30 superficial dentin and 30 deep dentin specimens. Dentin specimens of each depth were randomly distributed into two equal subgroups (N=15) and bonded by either Adper Prompt L-Pop (strong self-etch adhesive) or Adper Easy Bond (mild self-etch adhesive). Knoop hardness test was employed to evaluate degree of cross-linking of the adhesives. Data were analyzed with SPSS 16, using two-way ANOVA to compare mean hardness values of the study groups (p< 0.05). Results: There was no interaction effect between dentin depth and the type of adhesive (p= 0.36). Regardless of dentin depth, hardness of Adper Easy Bond was significantly higher than that of Adper Prompt L-pop (p< 0.001). Moreover, both the adhesives showed higher hardness when bonded to superficial dentin compared to deep dentin (p< 0.001). Conclusion: Degree of cross-linking of the self-etch adhesive with mild acidity was more than that of the strong self-etch adhesive after light-curing. Surface hardness of both adhesives was higher on superficial dentin compared to deep dentin.

Objective To study the effects of bacterial invasion and artificial saliva immersion on the bond strength and nanoleakage between healthy dentin and glass ceramics-bonded specimens using three types of resin cements and provide a reference for the selection of clinical bonding materials. Methods One hundred eight dentin blocks were selected to prepare bonded specimens with Variolink N, Multilink N, RelyX Unicem and glass ceramics blocks. The adhesive specimens of each type of resin cements were divided into three groups according to the aging method: bacterial invasiveness group (the specimens were cultured under anaerobic conditions for 14 days after inoculation with Streptococcus mutans), artificial saliva immersion group (the specimens were immersed in artificial saliva for 6 months), and control group (the immediate test group). Each group comprised 12 specimens: 6 were selected to test the bonding strength, and 6 were observed by scanning field emission scanning electron microscopy (FESEM). Results The bond strength of Variolink N in the immediate test group was significantly higher than that of Multilink N and RelyX Unicem, and the difference was statistically significant (P < 0.05). However, no significant difference was found in the bacterial invasiveness group and artificial saliva immersion group (P > 0.05). In the bacterial invasion group, the difference in the nanoleakage of the three adhesives was statistically significant (P < 0.05), with a trend of Variolink N > Multilink N > RelyX Unicem, and pairwise comparison was statistically significant (P < 0.05). The nanoleakage of the three resin adhesives showed an increasing trend in the bacterial invasion group and artificial saliva group compared with that of the immediate test group. Conclusion Both artificial saliva soaking and bacterial invasion can reduce the sealing property of the adhesive interface of 3 types of resin cements to different degrees. The presence of Streptococcus mutans in the oral cavity may reduce the sealing performance of the resin dentine adhesive interface.

Background: Dentinogenesis imperfecta type I (DGI-I) is a hereditary alteration of dentin associated with osteogenesis imperfecta (OI). Aim: To describe and study the morphological characteristics of DGI-I with scanning electron microscopy (SEM). Material and methods: Twenty-five teeth from 17 individuals diagnosed with OI and 30 control samples were studied with SEM at the level of the enamel, dentin–enamel junction (DEJ) and four levels of the dentin, studying its relationship with clinical–radiographic alterations. The variables were analysed using Fisher’s exact test, with a confidence level of 95% and asymptotic significance. Results: OI teeth showed alterations in the prismatic structure in 56%, interruption of the union in the enamel and dentin in 64% and alterations in the tubular structure in all of the cases. There is a relationship between the severity of OI and the morphological alteration of the dentin in the superficial (p = 0.019) and pulpar dentin (p 0.004) regions. Conclusions: Morphological alterations of the tooth structure are found in OI samples in the enamel, DEJ and dentin in all teeth regardless of the presence of clinical–radiographic alterations. Dentin structural anomalies and clinical dental alterations were observed more frequently in samples from subjects with a more severe phenotype of OI.

Objective. The aim of the present study is to compare the adhesive capacity of the microhybrid and nanohybrid diacrylic composite resins to enamel, dentin and cement. Materials and method. Standardized cavities were made at the cervical level on the vestibular surfaces of 8 maxillary third molars without caries or fractures. The cavities were filled with microhybrid (Filtek Z250 – 3M ESPE), respectively nanohybrid composites (Filtek Z550 – 3M ESPE), half of the teeth also receiving an intermediate layer of flowable composite (Gradia Direct LoFlo – GC). All of them were subjected to a thermocycling process (300 cycles in water of 5°C/55°C). After the isolation of the teeth with nail polish, they were introduced into 1% methylene blue for 24 hours. Subsequently, they were embedded in an epoxy resin (EpoThinTM 2 – Buehler), polished and sectioned mesiodistally with Beta Grinder/Polisher-Buehler. Sections were selected where the greatest degree of methylene blue penetration was detected to be analyzed by optical polarized light microscopy (Axio Imager A1m – Zeiss). Results. All teeth showed microinfiltration of the cement, while only half showed it also in enamel. There are no microinfiltration differences between micro- and nanohybrid composite resins. The intermediate layer of flowable composite does not influence microinfiltration.

Aim. The aim of this study is to evaluate the interface between resin and hard dental tissues obtained by using two adhesive systems. Material and method. Ten extracted human molars were bonded using a total etch adhesive (Adper Single Bond 2, 3M ESPE) and a self-etching agent (Futurabond U DC, VOCO), after artificially preparing MOD cavities on them. The composite build ups were constructed using Filltek Z550 nanohybrid composite from 3M ESPE. Teeth were embedded in epoxy resin, using special vacuum equipment, then metallographic grinded to a certain point of interest and polished. The samples were analyzed using a Carl Zeiss Optical Microscope (Axio Imager A1M) and the image acquisition was made using a dedicated microscope camera (Canon Powershot A640) and dedicated software (Axio Vision). Results. Resin-enamel bonds were uniform over the entire surface on both adhesive systems whereas resin-dentin bonds resulted using the total etch system are of inferior quality (there are micro spaces between dentin and resin that range from 6,18μm to 24,12μm) than the ones resulted using the self-etch adhesive, in which case the bonds were uniform and well adapted with no signs of micro spaces. Conclusions. Resin-dentin bonds resulted using a total etch adhesive may reduce the quality of the restoration, thus being susceptible to marginal infiltration and debonding over time.

Age estimation is a hot and difficult issue in forensic practice. Teeth are the most solid organs in human body and can be kept in vitro for a long time. With age, the secondary dentin gradually generates and the volume of pulp cavity constantly decreases. Therefore, forensic dentists proposed that age-related changes of dentin-pulp complex could be used to estimate age, which has been widely applied in forensic practice over the years. Due to the development of imaging technology, a variety of methods have been advocated by forensic dentists to detect the age-related changes of dentin-pulp complex for age estimation. However, different methods have their own advantages and limitations, forensic scientists should combine the use of different methods for improving the accuracy of age estimation according to the actual situation. This paper reviews current research of age estimation based on dentin-pulp complex, so as to provide reference for related research.