Comparison of two composite resin materials for splinting of dental luxation injuries: A double blind randomized controlled trial.

BACKGROUND/AIM: Luxation is a common traumatic dental injury treated with a wire composite (WC) splint. However, bulk-fill flowable composite and conventional packable composite have not been compared for retaining these splints. Therefore, the objectives of this randomized controlled trial were (1) to compare retention of WC splints, and (2) to compare adhesive point dimension, application and removal time, and effect on tooth mobility between the two WC splints. MATERIALS AND METHODS: In this parallel group, non-inferiority double blind randomized controlled trial, a total of 90 patients, aged 16-50 years participated. They were randomly allocated into two groups, the packable composite group (PC) n = 45 and the bulk-fill flowable composite group (BF-FC) n = 45 by lottery method. Following measurements were taken at the splint application appointment. Horizontal tooth mobility measured via Periotest, splint application time, and frontal images of splinted teeth to measure the percentage composite adhesive point area. After 2 weeks, splints were visually inspected for retention, whereas mobility and removal times were also recorded. Statistically, comparisons were made using independent samples sample T-test, Fisher's exact test, and Mann-Whitney U at p ≤ .05. RESULTS: A total of 88 patients with 156 luxated teeth completed the trial, as two patients were lost to follow-up. Two patients in the PC group reported with completely de-bonded splints while none de-bonded in the BF-FC group. Both groups were similar in terms of splint retention (p = .352), reduction of mobility (p = .426), and splint removal times (p = .372). The BF-FC group performed significantly better in adhesive point dimension percentages (p < .001) and splint application time (p < .001). CONCLUSION: Both groups were comparable in most parameters of the study. However, for BF-FC group application time and adhesive point dimension were significantly less.

A novel experimental model to investigate fungal involvement shows expression of Dectin-1 in periapical lesion pathogenesis.

BACKGROUND: Candida albicans is linked to persistent endodontic lesions. However, the recognition receptor that identifies it is not explored previously. OBJECTIVES: The aim of this study was to (1) establish a zymosan-induced model of apical periodontitis in mouse, (2) observe the expression of Dectin-1 and its possible relationship with toll-like receptor (TLR) 2 and (3) observe relationship between Osteopontin (OPN) and inflammatory cytokines. METHODS: A total of 138 Naval Medical Research Institute (NMRI) mice were randomly divided into; Experimental Group n = 69 and Zymosan Group n = 69. Periapical periodontitis was developed in right maxillary molar. The animals were sacrificed at 7, 21 and 42 days. Bone blocks containing the mesial root (n = 15 for qRT-PCR, n = 45 for enzyme-linked immune sorbent assay (ELISA)) were collected for mRNA expression and ELISA. While whole maxilla (n = 3 from each time interval) were used for histology and immunohistochemical analysis. One way analysis of variance (ANOVA) and Tuckey's posthoc was used for statistical analysis at p ≤ .05. RESULTS: TLR-2, Dectin-1 and TLR4-positive cells was detected at all time intervals in both groups. A strong positive correlation was observed between TLR-2 and Dectin-1 in both lesions (regular r = .680, p = .015, zymosan (r = .861, p < .001)). A significant correlation was found between OPN and tumour necrosis factor-alpha (TNF-α) in zymosan lesion (r = .827, p = .001). CONCLUSIONS: Immune cells of inflamed periapical tissue expressed Dectin-1 receptor in response to the microbial challenge from infected root canals and showed positive correlation with TLR-2 and OPN suggesting a possible receptor collaboration mediated by OPN. The expression of OPN and TNF-α showed positive correlation in response to fungal antigen, indicating a possible relationship.

Expression of Toll-like receptor 2, Dectin-1, and Osteopontin in murine model of pulpitis.

OBJECTIVES: This in vivo animal study aimed to develop a murine model of pulpitis induced by pulp exposure with or without application of zymosan in Naval Medical Research Institute (NMRI) mice and observe expressions of Toll-like receptor (TLR)-2, TLR-4, Dectin-1, Osteopontin (OPN), tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, and IL-1ß. MATERIAL AND METHODS: A total of 168 NMRI mice were divided into two groups, i.e., group A (n = 84) (pulpitis induced by pulp exposure only) and group B (n = 84) (pulpitis induced by pulp exposure and zymosan application). Right maxillary molar pulps were exposed with » round bur, and animals were sacrificed at 0, 6, 9, 12, 24, 48, and 72 h. The exposed teeth were obtained for real-time polymerase chain reaction (qRT-PCR) analysis and histological and immunohistochemistry (IHC) analysis. RESULTS: Histological evaluation revealed a time-dependent steady increase in inflammation. Similar time-dependent increase in the expression of inflammatory cytokines was noted. Group A exhibited an increase in TLR-4, Dectin-1, and OPN at 6 h, while TLR-2 was expressed at 24 h. Group B expressed TLR-2, Dectin-1, and OPN at 9, 48, and 72 h, respectively (p ≤ 0.05). Expression of OPN and TNF-α exhibited a similar pattern in both groups. IHC also detected expression of TLR-2, Dectin-1, TLR4, and CD68 in some cells at 6 and 9 h. CONCLUSIONS: NMRI mice provided for a stable pulp inflammation model. Zymosan may be used to develop pulp inflammation model and study inflammatory response towards fungal antigens. Dental pulp expressed Dectin-1 receptor. OPN and TNF-α exhibited a similar expression pattern. CLINICAL RELEVANCE: Innate immunity of dental pulp is capable of detecting fungal pathogens.

Effect of Natural and Artificial Dentin Conditioners on the Release of Vascular Endothelial Growth Factor.

INTRODUCTION: The purpose of this study was to observe the release of vascular endothelial growth factor (VEGF) after conditioning with etidronic acid (also known as 1-hydroxyethylidene-1 and 1-bisphosphonate [HEDP]) and phytic acid (inositol hexakisphosphate [IP6]) in comparison with EDTA on human dentin disks and cylinders. METHODS: Human dentin disks were disinfected and prepared by the standardized method. Seventeen percent EDTA, 9% HEDP, 1% IP6, and distilled water (5 minutes) were used to immerse dentin disks. The dentin cylinders were prepared by following disinfection and the standardized preparation method to achieve a truncated cone-shaped canal with a 1-mm open apex. The dentin cylinder samples were irrigated with sodium hypochlorite (5 mL/5 minutes) and then rinsed with 17% EDTA, 9% HEDP, 1% IP6 and distilled water (5 mL/5 min). Enzyme-linked immunosorbent essay was performed to measure VEGF release. One-way analysis of variance was used to compare the mean release of VEGF between study groups and controls at a significance level of .05. A post hoc Tukey test was used for multiple comparisons between study groups. RESULTS: Among conditioners, HEDP released more VEGF from both disks and cylinders. In cylinders, VEGF release by HEDP was significantly greater than the other conditioners, whereas in disks the release of VEGF was similar with all conditioners. CONCLUSIONS: The release of VEGF by 9% HEDP and 1% IP6 was comparable with 17% EDTA from dentin disks; however, HEDP demonstrated more release from dentin cylinders than EDTA and IP6.

Outcome Of Endodontic Procedures Performed By Dental Interns Using Stainless Steel And Niti Files: A 10- Year Retrospective Study.

BACKGROUND: Preparation of root canal according to its desired anatomy and complete disinfection is a laborious task. Several factors influence the endodontic treatment including operator's skill and knowledge, anatomy of the tooth, the instruments and equipment used. In the past stainless-steel instruments were used to prepare the root canal but it causes many iatrogenic errors. Nickel titanium instruments evolved to overcome the iatrogenic damages caused by stainless steel instruments. Keeping this in mind a comparative study was conducted on the clinical work of dental intern using stainless steel files and progressively taper nickel titanium instruments. The objective of this study was to compare the performance of interns using either stainless Steel or progressively tapered hand operated NiTi instruments. METHODS: This retrospective study included post-treatment radiographs of root canal treatments performed by interns by using either stainless steel files or NiTi Protaper files, in the endodontic department of Hamdard University Dental Hospital, Karachi, Pakistan. It was a 10-year audit, from 2008 to 2018, of endodontic performance. A total of 1219 post treatment radiographs of good quality and showing at least 2mm periapical area beyond the root apex were included. In SS group, preparation were performed by step back method, while in NiTi group the Protaper instruments for hand were used. Scoring criteria was used to evaluate technical quality. The data was analysed using SPSS for windows version 17.0. Chi-square test was used to determine difference in proportions between the outcomes in SS and NiTi groups at p0.05. RESULTS: A total of 1219 radiographs were included out of which 584 (47.9%) belonged to SS and 635 (52.1%) to NiTi group. Overall satisfactory performance was in 553 (45.4%) teeth. Treatment done with NiTi was only marginally better than that achieved with SS files (NiTi n=298 (46.9%), SS n=255 (43.7%)). In the SS group, there were more overfills and internal and external transportation (p<0.001). NiTi reported more cases of inadequate lateral seal and separated instruments (p<0.05). CONCLUSIONS: Endodontic performance of interns was not improved with progressive taper NiTi manual instruments.

Self-Reported Effectiveness of e-Learning Classes during COVID-19 Pandemic: A Nation-Wide Survey of Pakistani Undergraduate Dentistry Students.

OBJECTIVES: The main aim of this study was to determine the undergraduate dental students' self-reported effectiveness of online classes offered by various dental institutes of Pakistan. MATERIALS AND METHODS: A cross-sectional study was conducted using an online survey. A pretested and validated questionnaire comprising of 31 questions was circulated among dental students. The study participants were inquired about the perceived level of accessibility of resources and the effectiveness of online teaching. The data was analyzed using SPSS version 24. Mann-Whitney U test and Kruskal-Wallis test were used for statistical analysis at p ≤0.05. RESULTS: A total of 1,207 students from all over Pakistan responded. The majority of students was dissatisfied with the institutional learning management system and quality of learning resources available. Students were also dissatisfied with the level of training of teachers for online lectures. The worst rating was reported for questions related to the effectiveness of online classes (average rating: 3.83 and 3.781/5). First-year students reported poor interaction with teachers (p < 0.001) and strongly disagreed with the effectiveness of online classes (mean rating: 4.14 ± 0.935). CONCLUSIONS: The results from the present survey showed that dental students of Pakistan unanimously voiced dissatisfaction toward various elements of online teaching sessions. Findings from this survey will aid the academic institutes to establish proficient learning platforms focused on improving students` learning experience.

Erosive Potential of 1% Phytic Acid on Radicular Dentine at Different Time Intervals.

Objective: The objective of this in-vitro study was to compare the erosive potential and smear layer removal ability of 1% Phytic acid (IP6) and 17% Ethylenediaminetetaacetic acid (EDTA). Methods: Canal preparation of 225 single rooted extracted human teeth was performed with Protaper NiTi rotary instruments. Teeth were divided into three groups according to the final irrigation protocol. Group 1: Saline irrigation (n=75), Group 2: 17% EDTA (n=75), Group 3: 1% Phytic Acid (n=75). Roots were splitted and observed under Scanning Electron Microscope (SEM) for erosion and smear layer removal. Mean differences between the groups for smear layer removal and erosion were assessed using the Kruskal Wallis and Mann Whitney U test. (P≤0.05) Friedman and Willcoxon Signed Rank tests were used to make comparisons within the groups. Results: Group 3 was significantly less erosive than Group 2 at all root portions (P<0.001). With regards to smear layer removal, group 2 (EDTA) removed more smear layer compared to group 3 (Phytic acid) at all root portions (P<0.001). Both 17% EDTA and 1% IP6 removed significantly less smear layer in the apical root portion. Intra group comparisons revealed no significant differences at any root level. There was a time dependent increase in erosion and smear layer removal in Group 2, with severe erosion at 5 minutes time interval. In Group 3, however, there was moderate erosion and smear removal at 3 and 5 minutes interval. Conclusion: IP6 at the concentration of 1% and pH 3 was less erosive than 17% EDTA. It exhibited moderate smear layer removal ability.