فهرست مطالب

  • Volume:14 Issue: 1, 2020
  • تاریخ انتشار: 1399/01/28
  • تعداد عناوین: 11
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  • Faeze Jamali Zavare, Hanieh Nojehdehian*, Maryam Moezizadeh, Mehdi Daneshpooya Pages 1-11
    Background

    Mineral trioxide aggregate (MTA) and Calcium-enriched Mixture (CEM) cement are used for pulp capping since they induce the formation of a dentinal bridge. Long setting time is a shortcoming of these types of cement. This study aimed to assess the effect of the incorporation of some alkaline salts to MTA and CEM cement on their setting time, ion release profile, pH, and surface morphology.

    Methods

    In this in vitro experimental study, 5% calcium chloride (CaCl2), calcium oxide (CaO), sodium fluoride (NaF), and calcium nitrate [Ca(NO3)2] were separately added to MTA and CEM cement. The primary and final setting times of the cements were measured using a Gillmore needle apparatus. The samples were immersed in simulated body fluid (SBF) for one, seven, and 14 days and subjected to x-ray diffraction (XRD) and scanning electron microscopy (SEM) for phase identification and surface morphology assessment. The change in the pH of solutions was studied, and the calcium ion release profile was determined using inductively coupled plasma atomic emission spectroscopy (ICP-AES). The data were analyzed with ANOVA, followed by post hoc tests.

    Results

    CaCl2 and CaO decreased the setting time of MTA, and Ca(NO3)2 decreased the setting time of CEM cement. The incorporation of the salts increased the pH and calcium ion release from both cements, and hydroxyapatite deposits were noted to cover the surface of the samples (observed by SEM and confirmed by EDXA). Conclusion. The incorporation of CaCl2 and CaO into MTA and Ca(NO3)2 into CEM cement decreased their setting time and increased their pH and calcium ion release.

    Keywords: Calcium-enriched Mixture cement, calcium ion release, hydroxyapatite, MTA, setting time
  • Vitor Marques Sapata, Diogo Marques Sapata, Julio Araújo Gurgel, Antônio Medina Neto, Adilson LuizRamos* Pages 12-18
    Background

    This study evaluated the phase transformation of NiTi orthodontic wires and forces they release on deactivation.

    Methods

    The structural phase transformations of the following five thermo-activated nickel-titanium (NiTi) wires were evaluated using differential scanning calorimetry (DSC): Flexy Thermal Sentalloy® (GAC International), NiTi (35ºC) (Eurodonto), Thermo-Plus® (Morelli), FlexyNiTi® Flexy Thermal (35ºC) (Orthometric) and Damon® CuNiTi (35ºC) (ORMCO Corp.). The wires had a cross-section of 0.40 mm (0.016”). In addition, the forces they released were investigated using the three-point bending test. Five arches of each wire were tested using DSC (-20/80ºC at 10ºC/min), and six arches from each wire were sectioned for bending tests. The data were analyzed with ANOVA and post hoc Tukey tests. Pearson’s correlation test was performed between the results yielded by the DSC tests and those by three-point analyses (P=0.05).

    Results

    The DSC analysis showed differences between the NiTi alloys from all the manufacturers, with no differences between the lots of the same brand. ORMCO and Orthometric wires exhibited similar TTR values in cooling (P=0.49), and statistically similar TTR values in heating (P=0.056). The three-point bending test showed different patterns in releasing forces. A correlation was found between the DSC analysis and the three-point bending test results. Conclusion. The higher the temperature transformation was, the larger was the variation of force. All the wires presented higher forces at 3-mm deflection from 155 (±12.3) to 168.1 (±8) cN. The DSC analysis and the three-point bending test showed differences between the NiTi alloys from all the manufacturers.

    Keywords: Calorimetry, differential scanning, modulus of elasticity, nickel, Orthodontics, orthodontic wires
  • Mohammad Esmaeel Ebrahimi Chaharom, Mahmoud Bahari, Leila Safyari, Hossein Safarvand*, Hajar Shafaei, Elmira Jafari Navimipour, Parnian Alizadeh Oskoee, Amir Ahmad Ajami, Mahdi AbedKahnamouei Pages 19-25
    Background

    Due to the effect of pre-heating on the degree of conversion of composite resins and the possible effect on cytotoxicity, the effect of pre-heating of bulk-fill composite resins was investigated on cytotoxicity in this study.

    Methods

    In this study, three different types of composite resin were used, including Tetric N-Ceram Bulk-Fil, Xtrafil, and Xtrabase. From each composite resin, 10 cylindrical samples (5 mm in diameter and 4 mm in height) were prepared, with five samples preheated to 68°C, and the other five samples polymerized at room temperature (25°C). Twenty-four hours after polymerization, cytotoxicity was assessed by MTT assay on human fibroblasts. Statistical analysis of data was carried out with two-way ANOVA and Sidak Post-Hoc. The significance level of the test was determined at 0.05.

    Results

    There was no statistically significant difference between the mean percentage of cytotoxicity in terms of pre-heating (P>0.05), but the cytotoxicity of the studied composite resins was significantly different (P<0.001). The cytotoxicity of Tetric N-Ceram Bulk-fil composite resin was higher than that of the two other composite resins. Conclusion. Pre-heating of bulk-fill composite resin did not affect their cytotoxicity. In addition, the cytotoxicity of different bulk-fill composite resins was not the same.

    Keywords: Cell survival, composite resin, tetrazolium salts
  • William Buwembo *, Ian Guyton Munabi, Mark Kaddumukasa, Haruna Kiryowa, Muhammad Mbabali, Ethel Nankya, William Evan Johnson, Emmy Okello, Nelson K. Sewankambo Pages 26-36
    Background

    Periodontitis and rheumatoid arthritis have similar epidemiology and pathophysiology. Understanding the interaction between these two diseases is vital in our settings. We set out to assess the effect of oral hygiene interventions on disease activity of rheumatoid arthritis patients with periodontitis in Kampala, Uganda.

    Methods

    Fifty-eight patients attending an arthritis clinic with rheumatoid arthritis and periodontitis were randomly assigned to either an intervention group or a control group. Patients diagnosed with rheumatoid arthritis at least two years before, who were on the same medication, dose, or formulation for RA treatment during the preceding three months, were included. The patients were >18 years of age, would be available for all the study visits in the next six months, had at least six natural teeth, had periodontal disease classified as Dutch Periodontal Index (DPSI) >3 and provided written informed consent. Those who had a chronic disorder requiring chronic or intermittent use of antibiotics, were pregnant, were lactating, or had intent to become pregnant were excluded. The primary outcome measure was a change in Disease Activity Score of 28 Joints (DAS28 score) in two 3-month follow-up periods after the intervention. The secondary outcome measure was a change in periodontal status.

    Results

    There was a statistically significant improvement in the DAS-28 score in both the intervention and control arms during the follow-up period (P<0.01). The participants carrying more than one bacterial species had worse DAS-28 scores. Conclusion. Oral hygiene interventions given to RA patients could drastically improve their RA treatment outcomes, especially in resource-limited settings.

    Keywords: DAS-28 score, periodontitis, periodontopathogenic bacteria, pocket depth, rheumatoid arthritis
  • Sara Tavakolizadeh, Mohammad Javad Razaghi, Pedram Pakravan, Majid Sedaghat Monfared, Elaheh Beyabanaki *, Rahab Ghoveizi Pages 37-40

    Background. This study aimed to evaluate the effect of different pouring times and spacer thicknesses on the three-dimensional accuracy of casts made of 3D-printed custom trays. Methods. A partial edentulous maxillary model was scanned for fabricating custom acrylic trays. Twenty custom trays were created using a CAD/CAM system and divided into two groups in terms of their spacer thicknesses (2 mm and 4 mm). All the trays were designed with 2-mm thickness, multiple retentive holes measuring 2 mm in diameter, and three interior seating stops (two on the edentulous ridge and one on the incisal edge of the central incisors). Impressions were made using monophasic polyvinyl siloxane and poured in two different times (one hour and 24 hours after removal) with type IV dental stone. All the casts were scanned to measure three distances (inter-buccal cusps, inter-palatal cusps, and inter-fossa distances) between the two first premolars. The data were analyzed with two-way ANOVA and Bonferroni test at a significance level of 0.05. Results. There was no significant difference between the 3D accuracy of casts made using two different spacer thicknesses poured at 1-hour and 24-hour intervals. However, there was a difference between casts made after 1 hour and 24 hours when using custom trays with 2 mm of spacer thickness in terms of inter-buccal distance. Conclusion. There was no significant difference between the accuracy of casts made using custom trays with either 2 or 4 mm of spacer thickness, which were poured 1 hour or 24 hours after tray removal.

    Keywords: Computer-aided design, dental impression, three-dimensional printing
  • Diogo Marques Sapata, Adilson Luiz Ramos *, Sérgio Sábio, David Correa Normando, Renata CorreaPascotto Pages 41-47
    Background

    This in vitro study aimed to evaluate biofilm accumulation on and deactivation force of orthodontic nickeltitanium (NiTi) archwires before and after exposure to an oral medium.

    Methods

    Four commercial brands of orthodontic NiTi 0.016” archwires were examined before and after exposure to the oral medium for 4 weeks. Six archwire segments, 30 mm in length, from each manufacturer were tested in a device with four selfligating brackets, channel 0.022”, adapted to a universal test machine to evaluate the deactivation force between 0.5 and 3 mm of deflection. The presence of biofilm on the archwire surfaces was evaluated by scanning electron microscopy, before and after exposure to the oral medium. The Wilcoxon and kappa tests were applied to the biofilm scores, three-way ANOVA for repeated measures (Bonferroni post-test), and linear regression between biofilm and deactivation force.

    Results

    The exposure to the oral medium promoted moderate to severe presence of debris on the archwire surfaces and caused a reduction in deactivation force for the Ormco and GAC brands, while maintaining them with adequate force levels. The MORELLI and ORTHOMETRIC archwires underwent no significant reduction in deactivation force; moreover, these maintained elevated levels of force after exposure to the oral medium. The Spearman test indicated a low correlation between biofilm accumulation and deflection force for the Morelli (R2=0.132 and P=0.683) and Orthometric (R2=0.308 and P=0.330) brands. On the other hand, the GAC (R=0.767 and P=0.004) and ORMCO (R=0.725 and P=0.008) brands exhibited statistically significant correlation between these variables. Conclusion. Exposure to the oral medium for one month might give rise to significant changes in the dissipation of forces of orthodontic NiTi archwires, resulting from biofilm accumulation.

    Keywords: Modulus of elasticity, nickel, orthodontics, orthodontic wires, surface properties
  • Amin Saedi Germi, Vadoud Ghasemi Barghi *, Karim Jafari, Rahman Nemati, Saeed Yeganzad Pages 48-53
    Background

    Immediate single implant placement and restoration (IIR) is recognized as a novel method and is the main request of many patients. This study was designed to evaluate the aesthetic outcomes of immediately restored single implants placed in extraction sockets in theanterior maxilla.

    Methods:

    In this case series study, 18 patients were selected from two private clinics after placing a single-tooth implant in the anterior maxilla. Immediate provisional crowns were delivered on the following day or at most 48 hours later, and guidelines were provided. The Pink Esthetic Score (PES) questionnaire was used at 6- and 12-month follow-ups to assess aesthetic outcomes. Data were analyzed with single t-test and dependent t-test.

    Results

    In general, the results showed that the status of the mesial papilla, distal papilla, curve of the facial soft tissue line, level of the facial peri-implant mucosa and root convexity soft tissue in IIR method were optimal (P<0.05), with total PES means of 9.44±0.783 and 8.58±1.003 after 6 and 12 months, respectively. Also, the results showed a significant difference in PES between the 6-month and 12-month intervals (P<0.05). Conclusion. IIR is a viable method that resulted in optimal aesthetic outcomes based on PES in the short term. Considering its confirmation in this study and previous studies, it is recommended that dentists apply this method.

    Keywords: Aesthetics, immediate loading, single-tooth implant, soft tissue
  • Sangeetha Morekonda Gnaneswar*, Premkumar Sridhar Pages 54-60
    Background

    In sliding mechanics, archwires should slide easily during the retraction of anteriors. Round wires slide well, but the torque control is a significant problem. Rectangular wires produce effective torque expression but pose a challenge to free sliding due to factors like friction and force used to overcome friction, etc. To utilize the properties of both wires, the wire should be bi-dimensional. Dual-dimensional wire is one such wire with different dimensions in the anterior and posterior sections. This study aimed to compare the amount of space closure and anchorage loss of molars between the rectangular and dual-dimensional wire groups during retraction with mini-implants.

    Methods

    Forty patients were randomly allocated to two groups (n=20). Patients with rectangular wires formed the control group, and those with dual-dimensional wires formed the experimental group. Mini-implants and NiTi coil springs were used for retraction. Model and cephalometric analyses were carried out to calculate the amount of space closure and anchor loss, before and four months after the study. Statistical significance was set at P<0.05.

    Results

    The average amount of space closure was higher with DDW (3.98 mm) than rectangular wire (3.22 mm). The difference was statistically significant. No significant difference was found with anchorage loss. Conclusion. DDW can be used as an alternative to rectangular wires during retraction with mini-implants; however, it cannot replace the rectangular wires completely. Anchorage control was effective with both wires.

    Keywords: Dental implants, friction, orthodontic space closure, orthodontic wires
  • Nada Jaafar*, Hala Ragab, Ahmed Abedrahman, Essam Osman Pages 61-67
    Background

    The effectiveness of fissure sealants in caries prevention depends on their long-term retention and ability to stop caries progression. This randomized controlled clinical trial compared the retention rate and cariostatic properties of a contemporary glass-ionomer-based sealant (GIS) versus a resin-based sealant (RS) placed on fully erupted permanent molars in a split-mouth design.

    Methods

    The sealants were placed on fully erupted permanent teeth (8‒12 years of age) in 45 children. The evaluation was conducted after one week and three and six months.

    Results

    There was a statistically significant difference in the retention rate and caries transition between the two groups over a six-month clinical evaluation period. The resin-based sealant group showed a better retention rate than the GIS group (75.56% and 48.88%, respectively). The resin-based sealant was superior to GIS in preventing caries progression. Conclusion. Resin-based fissure sealant with fluoride releasing properties might be preferable in preventing caries progression of incipient non-cavitated carious lesions in fully-erupted teeth.

    Keywords: Fissure sealant, glass-ionomer, non-cavitated occlusal caries, sealants
  • Kumar Nilesh, Ashish Mahamuni, Swapnil Taur, Aaditee Vishnu Vande* Pages 68-72

    This paper reports a novel, minimally invasive, simple technique for the treatment of a displaced dentoalveolar fracture using a vacuum-formed splint in a 12-year-old pediatric patient. Vacuum formed splints have been reliable treatment options with limited morbidity and discomfort compared to other traditionally used procedures.

    Keywords: Fracture, mandible, pediatric, thermoformed splint, trauma
  • Les Kalman* Pages 73-76

    Determining the shade of dental materials is a challenging requirement for the restorative dentist. Improper shade selection is the second cause for laboratory remakes, resulting in inefficiency and additional cost, and unnecessary stress for the clinician and patient. The process of shade selection is somewhat subjective, with no consensus on the protocol. This research investigation aimed to develop a novel software application to provide an accurate, objective, and systematic approach to shade determination for teeth, soft tissues, and dental materials. An IOS software application was developed, termed Smile Shade, to facilitate a simple approach for dental shade determination. Smile Shade functions on a high-dynamic-range microcolor sensor with automatic temperature control and inter-device repeatability of <1.0 ∆E. The determination of shade is completed through the evaluation of color based on CMYK, RGB, and LAB, which are different techniques of storing colors. Further research is underway to compare this novel application to the traditional shade tab approach commonly practiced at most dental schools.

    Keywords: dental shade, shade determination, digital dentistry, medical device, restorative dentistry, prosthodontics