Journal of Dentistry, Shiraz University of Medical Sciences
Volume:21 Issue: 1, Mar 2020

Statement of the Problem: The most common cause of endodontic treatment failures is improper coronal sealing. Therefore, besides to proper root sealing, coronal sealing which is supported by a proper restoration has a major role in endodontic treatment success, and coronal microleakage should be considered as an etiologic factor in endodontic treatment failure. Glass-ionomer (GI) has been proposed as a coronal barrier for microleakage after endodontic treatment. This study aimed to evaluate the coronal microleakage in GI-obturated root canals in endodontically treated teeth using different thicknesses of GI. In this invitro study, forty-five single-rooted extracted human teeth with single canals were collected and disinfected with 0.5% chloramine solution. After endodontic treatment, teeth were divided into 3 groups. In the group 1 to 3, 1 to 3 mm of gutta-percha was removed and GI was replaced at 1-, 2- and 3-mm thicknesses respectively. Then subgroups were placed in methylene blue dye and the microleakage was assessed using dye penetration. The mean dye penetration in groups 1, 2 and 3 were 5.1, 3.7 and 2.9, respectively, with statistically significant differences. Group 1 exhibited the highest amount of dye penetration while group 3 showed the least one. Moreover, a significant difference between groups 1 and 2 (p= 0.002) and a non-significant difference between groups 2 and 3 (p= 0.098) was detected in mean dye penetration.   Thicker layers of GI might decrease the coronal microleakage. GI at 3-mm thickness resulted in the best protective effect on coronal microleakage in endodontically treated teeth, though further studies are needed to confirm these results.

Statement of the Problem: Oral lichen planus (OLP) is a chronic inflammatory oral mucosal disease with unclear etiology while a few cases of disease become malignant. This study aimed to evaluate the level of nitric oxide (NOx) and C-reactive protein (CRP) as oxidative stress and inflammation status in sample of OLP patients. In this case-control study, serum and salivary NOx and CRP levels were evaluated in twenty two OLP patients as the case group confirmed by clinical and histopathological diagnosis, and twenty two healthy control groups collected from Tooba oral pathology laboratory in Sari in 2016. The data were analyzed by using independent-samples t-test, Mann-Whitney U-test and Chi-square by using SPSS version 21. The statistical significant level was considered at p< 0.05. Salivary and serum NOx levels in case group showed statistically significantly higher than healthy control group (p= 0.035 and p= 0.001, respectively). CRP values were significantly higher both in serum (p= 0.001) and in saliva (p= 0.035). A significant correlation was found between CRP and NOx values in serum (r= 0.521, p= 0.0001) and saliva (r= 0.427, p= 0.045). Oxidative stress causes damage to organs in the human body. Correct understanding of oxidative stress and its association with free radicals and inflammatory markers related to oral disease are important for effective treatments. The results of the study supported the effects of NOx and CRP levels in pathogenesis of OLP. Regarding antioxidant drugs could probably be considered in the treatment of OLP.

Statement of the Problem: The progression of incipient carious lesions may be simply prevented by non-invasive remineralization of lesions, eliminating the need for invasive and high-cost restorative procedures. This study aimed to assess the effect of two commonly used remineralizing agents and resin infiltration on surface micro hardness of incipient enamel lesions at different time points. In this in vitro study 45 intact human maxillary central incisors were selected. After disinfection, enamel samples measuring 5x5x2.5 mm were cut out of the labial surface of the teeth. The surface of samples was polished and they were mounted in auto-polymerizing acrylic resin. According to Amaechi’s method samples were immersed in acidified hydroxyethylcellulose system (pH = 4.5) for 96 hours to induce white spot lesions (WSLs). The baseline surface micro hardness of samples was measured using a Vickers hardness tester, then the samples were randomly divided into three groups (n=15) based on different remineralization MI-Paste Plus, Remin Pro and ICON-Infiltrant according to the manufacturer’s instructions. All samples were stored in anti-dry mouth treatment agent during the experiment and their surface hardness was measured at 15 days (T1) and 20 weeks (T2).   The hardness of samples in MI-Paste Plus and Remin Pro groups significantly increased at both T1 and T2 (p< 0.001) but this increase was not significant in ICON group (p> 0.05). MI-Paste Plus and Remin Pro can efficiently increase the hardness of incipient enamel lesions.

 Tissue engineering was an idea and today becomes a potential therapy for several tissues in dentistry such as Periodontal Disease and oral mucosa.

Periodontal regeneration is one of the earliest clinical disciplines that have achieved the therapeutic application of tissue engineering. The aim of the presence study was to prepare electrospun Poly(3-hydroxybutyrate) (PHB)/1% Carbon nanotubes (CNTs) scaffolds for periodontal regeneration.

1% w/v of CNTs was added to the polymer solutions and electrospinning. Physical properties of the scaffolds were evaluated by Scanning electron microscopy (SEM) and universal testing machine. Chemical characterization of the scaffolds was also assessed by Fourier-transform infrared spectroscopy (FTIR). Biological properties of the scaffolds were also evaluated in vitro by culturing periodontal ligament stem cells (PDLSCs) on the scaffolds for 10 days and in vivo by Implanting the scaffolds in rat model for 5 weeks.

Results showed that the scaffolds were mimicked fibrous connective tissue of the (PDL). CNTs improved the mechanical properties similar to 23-55 years old human PDL. In vitro biocompatibility study showed more attachment and proliferation of the PDLSCs for PHB/1%CNTs scaffolds compared to the PHB controls. In vivo study showed that CNTs in the scaffolds caused mild foreign body type giant cell reaction, moderate vascularization, and mild inflammation.

In conclusion, the results showed that the PHB/1%CNTs composite scaffolds may be potentially useful in periodontal regeneration.

Statement of the Problem: Head and neck cancer treatment has provided better cure and survival rates but the patient’s quality of life is still an issue. To verify the correlation between the three most used instruments for evaluating the quality of life of head and neck cancer patients. The study evaluated patients treated for head and neck cancer at the Mato Grosso Cancer Hospital, Cuiabá, MT, Brazil. The variables age, gender, cohabitation status, education, religion, smoking, ethnicity, tumor location and histological type and treatment modality were collected. The patients quality of life was assessed by the Functional Assessment of Cancer Therapy Quality of Life Measurement System (FACT-H&N), University of Washington Quality of Life Questionnaire (UW-QOL), and EORTC QLQ-C30/EORTC QLQ-H&N35 of the European Organization for Research and Treatment of Cancer. The study population consisted of 33 individuals with a mean age of 63.42 ± 11.25 years; 69.70% were males; 54.55% had no partner; 45.45% had only elementary education; 87.9% followed a religion; 84.38% were smokers and 87.50% alcoholics. Squamous cell carcinoma responded for 78.79% of the cases and palate/oropharynx and mouth floor (21.21% each) were the most affected sites. All patients underwent radiotherapy, 90.91% chemotherapy and 63.64% surgery. On the analysis of quality of life, shoulder (UW-QOL), social performance (EORTC QLQ-C30/QLQ-H&N35) and overall well-being (FACT-H&N) had the highest scores while saliva (UW-QOL), nausea and vomiting (EORTC QLQ-C30/QLQ-H&N35) and emotional well-being (FACT-H&N) had the lowest scores. A positive correlation was found between the questionnaires for the patient's overall quality of life and the domains: Pain, Appearance, Activity, Deglutition, Chewing, Speech, Taste, Saliva, Mood and Anxiety. Given the correlation between the questionnaires, the selection of the instrument for future research involving head and neck cancer patients’ quality of life should consider the specific aspects to be evaluated.

Statement of the Problem: Low pH of self-etch adhesives might cause suboptimal polymerization. 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. 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). 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). 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.

Statement of the Problem: Several additives have been introduced to decrease the setting time of MTA (mineral trioxide aggregate). For clinical applications, it is essential to investigate the biocompatibility of these materials. The present study evaluated the tissue response to MTA that has been separately mixed with citric acid, calcium lactate gluconate (CLG), and Na2HPo4. In this experimental studyTwenty one Wistar rats were divided into three groups of 7, 14 and 30 days follow up periods. Sterile polyethylene tubes were subsequently filled with MTA separately mixed with distilled water, 0.1% citric acid, 0.43% calcium lactate gluconate (CLG) and 15% Na2HPO4 and afterwards implanted subcutaneously. Empty tubes were implanted as negative control. At the end of their respective periods, the animals were sacrificed by anesthetic overdose and a biopsy was performed. The inflammatory responses were scored, classified and statistically analyzed using Kruskal-Wallis and Man-Whitney [V1] tests. Statistical significance was defined as p< 0.05. There was no significant difference between test groups in any time period after implantation but the mean values of inflammatory responses were significantly more than that of the negative control group (p> 0.05). The mean values of inflammatory responses were decreasing over time in all test groups. These values did not significantly differ in any group except the CLG and Na2HPO4 groups. The inflammatory responses induced by MTA mixed with citric acid and MTA mixed with Na2HPo4 were comparable to that of the control MTA. MTA mixed with CLG provoked a moderate-to-severe inflammatory response at 7 days after implantation, so further study is required before clinical application of this cement

Statement of the Problem: Recently, new compound of 3, 5-dimethyl-1-thiocarboxamide pyrazole has been composed with excellent antibacterial property. Biocompatibility and its effects on mechanical properties of dental composites should be considered before clinical use. The purpose of this study was to evaluate the biocompatibility of 3, 5-dimethyl-1-thiocarboxamide pyrazole as a new antibacterial compound and its effect on the mechanical properties of dental composites. In this experimental study, a new antibacterial compound was synthesis by reaction between Thiosemicarbazide and 2, 4-Pentandione and tested on thirty male albino Wistar rats weighting 200-250gr. Rats were randomly divided into 3 groups of 10, each rat received 3 implants of 3,5-dimethyl-1-thiocarboxamide pyrazole, penicillin v and empty polyethylene tube. A pathologist, who was unaware of types of tested materials and timing, performed the examination of specimens. The depth of cure and flexural strength of resin composite was measured using Iso4049 standard technique. Compressive strength was determined according to Iso9917 standard. This compound was biocompatible and there was no significant difference in flexural strength and compressive strength of the composites containing 1% of this compound with the control group (p> 0.05). The 3, 5-dimethyl-1-thiocarboxamide pyrazole with a concentration of 1% in flowable composites can be very effective in preventing secondary caries.

Statement of the Problem: Despite yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) high strength in dental restoration application, Zr- the framework has a low tendency to react chemically with cement which is the main reason of these restoration failures. The aim of this in-vitro study was to evaluate the effect of Y-TZP coating by nanocomposite of silica and aluminosilicate according to the sol-gel dip-coating technique on the bond strength of resin cement to Y-TZP.   In this experimental study, Y-TZP blocks (10×10×3  ) were prepared and sintered and assigned into 4 groups (n=10) for coating including control group without any further surface treatment, sandblasted using 110 μm alumina particles under 2.5 bar and tip distance of 10 mm, silica sol dip coating + calcination, aluminosilicate sol dip coating+ calcinations. To confirm chemical bonds of sol-gel covers, Fourier transforms infrared spectroscopy (FT-IR) technique was used. The surface of the sample was investigated by Scanning electron microscopy (SEM), energy-dispersive spectroscopy detector (EDS) and x-ray diffraction (XRD) methods. Micro-shear bond strengths (µSBS) of zirconia-cement specimens were evaluated. Data were analyzed with a one-way ANOVA test in SPSS version 11.5 software with a confidence interval of 95%.  µSBS of sandblasting, nano-silica, and nano-aluminosilicate specimens were significantly higher than control. µSBS of nano-silica was higher than other groups but no significant difference was observed in µSBS of sandblasting nano-silica, and nano-aluminosilicate groups (p Value > 0.05). Covering the zirconia surface with non-invasive nano-silica and nano-aluminosilicate using the sol-gel technique leads to improved cement bond strength.

Immediate placement of dental implants presents many challenges, especially when partial or complete fixed restorations are the intended prosthetic outcome. With modern advancements in CAD/CAM technology, the ease and predictability of such complex cases is vastly improved. However, certain clinical situations remain that preclude the traditional implementation of this controlled approach to implant planning/placement and the current solutions to these problems each impose some level of compromise. This article describes a technique permitting both prosthetically-driven implant planning and increased surgical guide accuracy in situations where existing hopeless teeth would otherwise impede optimal treatment.

Ewing's sarcoma is an uncommon malignancy primarily affecting bone tissue and usually occurs in adolescents and young adults. This paper reports a rare case of extra-skeletal Ewing’s sarcoma of the oral cavity soft tissue. In the clinical examination, a mass of 1.5×1.5 cm in diameter was observed in the right mandibular vestibule. Radiographic examination revealed no involvement of mandible. Microscopically, the tumor was composed of malignant small round cell tumor that exhibited immunoreactivity for CD99. The patient was subjected to enucleation surgery under local anesthesia, prognosis was excellent, and the patient remained symptom-free after 13 months.

Melanotic neuroectodermal tumor of infancy is a rare, rapidly growing, painless, pigmented neoplasm with neural crest derivation. It usually occurs during the first year of life and there is a prominent predilection for the maxilla. The purpose of the present report is to describe additional case of melanotic neuroectodermal tumor of infancy of maxilla in a 6-month-old infant male. The treatment included surgical excision with safe margins. No attempt was made for immediate grafting of the surgery site due to high proliferation rate of tissues and self-renewal during infancy. The facial growth was normal and the surgical cleft was tightly closed. Due to the rarity of tumor, essential knowledge on characteristics of this lesion would contribute to a proper diagnosis and benefit treatment planning.