JOURNAL OF DENTAL RESEARCH, DENTAL CLINICS, DENTAL PROSPECTS
Year:2018 | Volume:12 | Issue:1|Papers Count:12

Background: Mineral trioxide aggregate (MTA) is a material that has recently gained popularity in the application of the vital pulp therapy. Along with the increasing use of MTA to this end, the permanent restoration material to be placed on MTA has become a significant issue. The aim of this in vitro study was to investigate the bond strength of the novel low-shrinkage silorane-based composite resin (SBC) to MTA.Methods: Twenty acrylic blocks filled with MTA were prepared for this study. SBC was the test group and methacrylate-based composite resin (MBC) was used as the control group. Shear bond strength test was performed to determine the bond strength. The surfaces of broken samples were evaluated under a stereomicroscope and grouped as adhesive, cohesive and mixed. Data were examined by statistical analysis.Results: Statistical analysis revealed that SBC exhibited higher shear bond strength than the control group. It was observed that most of the failures in the test group were of cohesive type within MTA.Conclusion: Based on the results, SBC showed higher shear bond strength than the control group; however, clinical follow-up is needed to evaluate the clinical success.

Background: The aim of this study was to compare the push-out bond strengths of calcium silicate-based ProRoot MTA and Biodentine cements and SureFil SDR and EverX Posterior bulk-fill composite resins.Methods: Twenty-four single-rooted maxillary central incisors were sectioned below the cementoenamel junction, and the root canals were instrumented using rotary files. Thereafter, a parallel post drill was used to obtain a standardized root canal dimension. The roots were randomly assigned to one of the following groups with respect to the intra-orifice barrier used: ProRoot MTA; Biodentine; SureFil SDR; EverX Posterior. Five 1-mm-thick sections were obtained from the coronal aspect of each root. Push-out bond strength testing was performed and data were analyzed with Kruskal-Wallis and post hoc Dunn tests (P<0.05).Results: SureFil SDR and EverX Posterior bulk-fill composite resins’ bond strengths were significantly higher than ProRoot MTA and Biodentine calcium silicate cements. However, no statistically significant differences were observed between bulk-fill composite resins values and calcium silicate cement values.Conclusion: Within the limitations of present study, calcium silicate-based ProRoot MTA cement’s push-out bond strength was lower than those of Biodentine, SureFil SDR and EverX Posterior materials.

Background: This study was undertaken to evaluate the repair bond strength of lithium disilicate glass ceramic to a silorane-based composite resin after surface preparation with Nd: YAG and Er, Cr: YSGG lasers.Methods: A total of 102 lithium disilicate glass ceramic samples (IPS e.max Press), measuring 5 mm in diameter and 4 mm in thickness, were randomly assigned to 6 groups (n=17): group 1, no surface preparation (control); group 2, acid etching with 9.5% hydrofluoric acid (HF); group 3, surface preparation with 4.5-W Nd: YAG laser; group 4, surface preparation with 6-W Nd: YAG laser; group 5, surface preparation with 1.5-W Er, Cr: YSGG laser; and group 6, surface preparation with 6-W Er, Cr: YSGG laser. After preparation of surfaces and application of silane, all the samples were repaired with the use of a silorane-based composite resin, followed by storage in distilled water at a temperature of 37°C for 24 hours and thermocycling. Finally, the samples were subjected to a shearing bond strength test; the fracture modes were determined under a stereomi-croscope.Results: There were significant differences between the HF group and the other groups (P=0.000). Two-by-two comparisons of the other groups revealed no significant differences (P>0.05).Conclusion: Use of HF proved the most effective surface preparation technique to increase the repair bond strength between lithium disilicate glass ceramic and silorane-based composite resin; compared to the control group.

Background: Various occlusal schemes have been introduced over the years to enhance the stability, comfort, beauty and function of complete denture, of which lingualized, bilateral balanced and monoplane occlusions are the most recommended. The aim of this study was to compare the strain in mandibular denture-supporting structures in three different occlusal schemes.Methods: Two mandibular and maxillary models were simulated using epoxy resin, and strain gauges were embedded on each side of the mandible in mental foramen, buccal shelf and distolingual area. Strain values were measured in three occlusal schemes at centric occlusion protrusive and lateral movements. Data were analyzed with one-way and three-way ANOVA, followed by post-hoc Tukey tests. The significant level was set at 0.05.Results: The mean strain in denture-supporting area was lower in monoplane occlusion than the two other occlusal schemes, and the mean of values in the buccal shelf was higher than that of mental foramen and distolingual area. In all the three occlusal schemes, the mean strain values on the working side were higher than those on the non-working side during eccentric movements.Conclusion: Monoplane occlusal scheme imposed lower strain on denture-supporting area, with the buccal shelf being the primary strain-bearing area to tolerate more pressure than the rest of the denture-supporting areas. In terms of strain distribu-tion scheme, in all the three occlusal schemes, the working side received more strain than the non-working side during eccen-tric movements.

Background: In the current scientific literature there are only few studies on the immediate functional loading of single implants. The aim of the present present study was to evaluate the 4-year survival rate, complication rate and peri-implant marginal bone loss (PIMBL) of immediately loaded single implants inserted in healed ridges and fresh post-extraction sites.Methods: Six centers were involved in this prospective study. The surgical and prosthetic protocol was defined in detail, before the start of recruiting patients. Recruitment of patients and performance of surgeries took place between February 2012 and February 2013. Criteria for inclusion were single-tooth gaps in healed ridges and fresh post-extraction sockets. All the fixtures (AnyridgeÒ, Megagen Corporation, Gyeongbuk, South Korea) were functionally loaded immediately after insertion and followed for a period of 4 years. Outcome measures were implant survival, complications and PIMBL.Results: Forty-six patients (18‒73 years of age) were selected. In total, 57 fixtures were placed (10 in fresh post-extraction sockets). After 4 years of functional loading, only one fixture was lost; therefore, high survival rates (97.6% patient-based; 98.1% implant-based) were reported. In addition, a limited incidence of biologic (4.8% patient-based; 3.8% implant-based) and prosthetic (9.7% patient-based; 7.6% implant-based) complications was reported. The overall 4-year PIMBL amounted to 0.38±0.21 mm (healed ridges: 0.4±0.21 mm; fresh post-extraction sockets: 0.33±0.20 mm).Conclusion: Loading single implants immediately seems to be a highly successful treatment modality. However, long-term data are needed to confirm these positive outcomes.

Background: In successful replacement of a tooth with a dental implant, soft tissue esthetic is as important as stability and function of the implant. Quality and quantity of the peri-implant mucosa can influence esthetic outcomes. This study assessed implant esthetic success of two different implant systems. In this regard the interdental papilla was evaluated and the relation-ship between implant type and crestal bone loss adjacent to implant was assessed.Methods: Eighteen patients (11 males, 7 females) with a total of 18 implants participated in this historical cohort study. Patients were divided into two groups based on the type of implants: Implantium group and SPI group; 36 interproximal papillae were evaluated photographically, using Jemt’s papillary presence index (PPI). Radiographic analysis was carried out to find out the relation between bone loss and type of implant. Analysis of data was performed with SPSS 18, using Fisher's exact test, independent t-test, Spearman's correlation coefficient and ANOVA.Results: Comparison of photographs did not show a statistically significant difference in PPI between the two groups (P=0.94). Radiographic evaluation of crestal bone loss adjacent to implant shoulder did not reveal significant differences between the two groups (P=0.30).Conclusion: Implant therapy in the anterior maxilla, using Implantium or SPI system, did not result in significant differences in esthetics. In this study, there was an inverse relationship between the distance of contact point to bone crest and papilla index (P=0.002 in the SPI group) (P=0.02 in the Implantium group).

Background: Recurrent aphthous stomatitis (RAS) is a disorder characterized by recurring ulcers involving the oral mucosa in patients with no other signs of disease. The current concept of etiopathogenesis is that RAS is a clinical syndrome with several possible etiologies. The process seen in RAS is probably initiated through an as yet unidentified antigenic stimulation of the mucosal keratinocytes, which stimulates secretion of T-cell activation cytokines ‒ interleukins and tumor necrosis factor alpha (TNF-a). TNF-a causes inflammation by its effect on endothelial cell adhesion and neutrophil chemotaxis. The rele-vance of TNF-a to the pathogenesis of RAS has stemmed from the observations that anti- TNF-a drugs such as thalidomide and pentoxifylline have been found to be effective in the treatment of RAS. Therefore, the present study was an attempt to measure the levels of salivary TNF-a in patients with RAS, which will reflect the local production of cytokines at the site of the disease. The aim was to evaluate the salivary levels of TNF-a in patients with recurrent aphthous stomatitis.Methods; The study comprised of 60 subjects, of whom 30 clinically proven RAS patients of either sex were selected as cases and 30 healthy, age- and gender- matched subjects were selected as controls. After taking informed consent, 5 mL of unstimulated saliva were collected from both the study and control group subjects. Determination of salivary TNF-a levels was carried out by Enzyme-Linked Immunosorbent Assay (ELISA) and expressed in pg/mL. Statistical analysis of the RAS and control groups was carried out using unpaired t-test. Gender-wise comparison of salivary TNF-a levels in the study and control groups was carried out using one-way ANOVA.Results: Mean salivary TNF-a levels were significantly higher in the RAS group compared to the control group (P<0.001). It was also revealed that the mean salivary TNF-a levels in females were significantly higher than in males in the study group (P<0.05).Conclusion: It is fair to suggest that TNF-a plays a very important mediatory role in the pathogenesis of RAS and may play an important role in the search for a definitive treatment for the disease.

Background: Diode lasers (DLs) have demonstrated equal or better desensitizing effects than fluoride varnish, 10% potas-sium nitrate (NK) gel and Gluma. The current study evaluated the desensitizing effect of combined application of DLs with two different output powers and compared it with single DL therapy.Methods: Sixty-two hypersensitive teeth were allocated randomly into two groups: the single group was treated with 3-W DL beam once and in the combined group, the teeth were irradiated three times (the first time with 0.2-W and then with 3-W and the second and third times, 48 and 96 hours after the baseline visit, with 0.2-W DL beams). The amount of dentin hyper-sensitivity (DH) was evaluated, immediately before and after each visit, and 1 week and 1 and 3 months after the first visit. Data analysis was performed using chi-squared test, repeated measurement of ANOVA and Mann-Whitney U test. P<0.05 was considered statistically significant.Results: Statistically significant changes were observed in the means of VAS indices between all the measurement intervals and pretreatment measures, in both experimental groups (P<0.001). The difference in VAS reduction among the groups was not significant when the hypersensitive teeth were stimulated by a periodontal probe and a jet of air (P=0.63 and P=0.12).Conclusion: The results of the present study showed that using both high-intensity and combined DL beams gives rise to significant reductions in DH. There was no significant difference between combined and single laser therapies in the treatment of tooth hypersensitivity.

Background: Bracket base design is a factor influencing shear bond strength. High shear bond strength leads to enamel crack formation during debonding. The aim of this study was to compare enamel damage variations, including the number and length of enamel cracks after debonding of two different base designs.Methods: Eighty-eight extracted human premolars were randomly divided into2 groups (n=44). The teeth in each group were bonded by two types of brackets with different base designs: 80-gauge mesh design versus anchor pylon design with pylons for adhesive retention. The number and length of enamel cracks before bonding and after debonding were evaluated under an optical stereomicroscope ×40 in both groups. Mann-Whitney U test was used to compare the number of cracks between the two groups. ANCOVA was used for comparison of crack lengths after and before debonding in each group and between the two groups.Results: There was a significant increase in enamel crack length and numbers in each group after debonding. There was no significant difference in enamel crack numbers after debonding between the two groups, whereas the length of enamel cracks was significantly greater in anchor pylon base design after debonding.Conclusion: Bracket bases with pylon design for adhesive retention caused more iatrogenic debonding damage to enamel surface.

Background: The present study aimed to compare the shaping ability of Reciproc Blue instruments with or without the creation of a glide path in simulated S-shaped root canals.Methods: Root canals of thirty #15.02 clear resin S-shaped blocks were dyed using ink and photographed. Then the blocks were randomly divided into 2 groups: group A: Reciproc Blue with glide path created with ProGlider and group B: Reciproc Blue with no glide path preparation (n=15). The blocks were also photographed after preparation. The pre- and post-prepara-tion images were superimposed and evaluated at 9 different measurement points according to the 3 zones, as coronal straight, first curvature, and apical curvature zones. The data were evaluated with independent t-test or Kruskal-Wallis tests with 5% significance interval.Results: Group B removed greater amount of material from the inner aspect of simulated canal at the first curvature and apical curvature zones and from the outer aspect of the canal at apical curvature zone (P<0.05). Both groups exhibited trans-portation and the transportation width in group B was significantly greater in the levels of apical curvature zone (P<0.05).Conclusion: Glide path preparation using ProGlider rotary instrument improved the shaping ability of Reciproc Blue R25 instrument by leading to less transportation and maintaining centering ability.

The aim of this systematic review was to investigate the effect of treatment duration on children’s behavior and/or anxiety in the dental setting. To this end, a systematic search was conducted in Pubmed/Medline and Scopus from 1970 to march 2017 for English language articles that assessed the relationship between dental treatment duration or length, and fear/anxiety or behavior in children aged<12 with no confounding medical and/or psychological history and neuro-psychiatric disabilities. Four studies investigating the effect of treatment duration on children’s behavior during and/or after treatment were included. None of the reviewed studies investigated the effect of treatment duration on children’s dental anxiety or fear. There was a general tendency towards deterioration of children’s behavior with an increase in treatment duration. In conclusion, our results undermine the validity of current suggestions about the appropriate treatment duration. Further clinical trials are needed to establish appropriate treatment duration for more effective behavioral management of pediatric patients during dental procedures.

Indirect non-metal restorations restore the function and esthetics of severely carious or broken teeth. This report explores a novel approach for the impression, model fabrication and provisionalization of a pin reinforced-onlay (pinlay) preparation. A dentoform molar was prepared for a pinlay indirect restoration. An impression, model and a provisional were fabricated with the employed pins and determined to be clinically acceptable. The pinlay may offer the patient and clinician another treatment option for oral rehabilitation.