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Dental Materials and Techniques - Volume:2 Issue: 1, Winter 2013

Journal of Dental Materials and Techniques
Volume:2 Issue: 1, Winter 2013

  • تاریخ انتشار: 1391/12/08
  • تعداد عناوین: 7
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  • Ali Bagherpour, Maryam Mohammadzadeh Rezaei, Shahrokh Nasseri Page 1
    Precise localization of the third molars in relation to the inferior alveolar nerve canal is critical from a clinical point of view and strongly affects the surgical treatment outcome. Recently, by using three-dimensional modeling software, the relationship of third molar root apices and inferior alveolar nerve canal can be better understood. In this study, the spatial relationship of two surgical sites of 19 impacted third molars with close relationship to the inferior alveolar nerve canal is described by using imaging data from a cone beam computed tomography system. This study aimed to investigate the ability of three-dimensional modeling of tooth-nerve relationship using the data imported to Amira 5.2.2 imaging software.
    Keywords: Cone beam computed tomography, inferior alveolar nerve, mandibular third molar, volume rendering
  • Alireza Boruziniat, Morteza Babazadeh, Mahshid Gifani Page 6
    The aim of this study was to evaluate the effect of chlorhexidine (CHX) application on immediate and two-month bond strength of a filled adhesive system.
    Methods
    Forty eight non-carious human third molars without enamel of occlusal surface were randomly divided into two main groups according to CHX application: control and CHX. Each main group was further subdivided into 2 subgroups depending on storage time: immediate or two-month collagenase storage. In CHX groups, 2% CHX was applied for 30 s. Filled adhesive resin (PQ1) was applied on the etched dentin surfaces and cured in all experimental groups. Composite resin (Amelogen) was placed on the dentin surfaces and shear bond strength (SBS) was evaluated immediately and after two-month storage in collagenase solution. Failure modes were determined by stereomicroscope.
    Results
    There was no significant difference in immediate SBS between groups (P>0.05). After two-month collagenase storage, although SBS was significantly reduced in control group (P<0.05), no significant reduction was observed in CHX group (P>0.05). SBS in CHX group was significantly higher than the control group (P<0.05).
    Conclusion
    The use of CHX had no adverse effect on immediate bond strength of filled adhesive and could preserve the bond strength.
    Keywords: Bond durability, chlorhexidine, collagenase, filled adhesive
  • Maryam Talebi, Behjatolmoluk Ajami, Rasoul Sahebalam Page 11
    The objective of this study was to gather information about normal occlusion and arch dimensions in the primary teeth of the children belonging to an Iranian population.
    Methods
    This descriptive cross-sectional study was performed on 68 children from the city of Mashhad in the 3-5 age range. Dental arch dimensions, interrelationships of primary canine and second molars, overbite and overjet were evaluated. Primate space was observed on both sides of the arch in 82.2% of the subjects. The most prevalent type of primary molar relationship was flush terminal plane (52.1%) followed by distal step (31.3%) and then mesial step (16.7%). The primary canine relationship was ranked in the descending order of prevalence as Class I (77.1%), Class II (13.5%), end-to-end (5.2%) and Class III (4.2%). Normal overbite and normal overjet was observed in 50% and 81.3% of cases, respectively.
    Conclusion
    This study provides an insight into the dental arch dimensions, occlusion, spacing and crowding in primary dentition in Iranian children. In most of the cases, primate space and flush terminal plane were observed.
    Keywords: Arch dimensions, occlusion, primary dentition
  • Baratollah Shaban, Elham Moradi, Amir Hossein Nejat, Somayeh Sabzali Zanjanhkhah, Touraj Vaezi Page 17
    Epinephrine-containing lidocaine is the most used anestheic drug in dentistry. The aim of this study was to investigate the hemodynamic changes following local infiltration of 2%lidocaine with 1:80,000 epinephrine in subjects undergoing orthognatic surgery under general anesthesia.
    Methods
    Twenty five patients without any systemic disease participated. After general anesthesia, two cartridges of 2% lidocaine + 1:80,000 epinephrine were infiltrated around the surgery site. Systolic (SBP) and diastolic (DBP) blood pressure, mean arterial blood pressure (MAP), heart rate (HR), and blood sugar (BS) were measured in three stages: before the injection (M1), at the end of injection (M2), and 10 min after injection (M3).
    Results
    No significant difference observed in SBP, DBP, and MAP at the end of injection and 10 min later. HR was increased significantly after injection and remained significantly higher than baseline after 10 min. BS increased slightly at the end of injection and continued to increase after 10 min. However, changes in BS were not significant.
    Conclusion
    Using two cartridges of epinephrine-containing lidocaine have slight systemic changes in healthy subjects; as a result, this dosage could be used in patients with cardiovascular complications undergoing general anesthesia.
    Keywords: Blood pressure, epinephrine, Heart rate, lidocaine, local anesthesia
  • Berahman Sabzevari Page 21
    The aim of this study was to compare the microleakage of beneath the orthodontic brackets bonded with 3 different bonding techniques and evaluate the effect of thermocycling.
    Methods
    One hundred and twenty premolars were randomly divided into 6 groups, received the following treatment: group 1: 37% phosphoric acid gel+Unite primer+Unite adhesive, group 2: 37% phosphoric acid gel+ Transbond XT primer+Transbond XT adhesive, group 3: Transbond plus Self Etching Primer (TSEP)+Transbond XT adhesive. Groups 4, 5, and 6 were similar to groups 1, 2, and 3, respectively. Evaluation of microleakage was done following to thermocycling test. After bonding, the specimens were sealed with nail varnish except for 1 mm around the brackets and then stained with 0.5% basic fuchsine. The specimens were sectioned at buccolingual direction in 2 parallel planes and evaluated under a stereomicroscope to determine the amount of microleakage at bracket-adhesive and adhesive-enamel interfaces from gingival and occlusal margins.
    Results
    Microleakage was observed in all groups, and increased significantly after thermocycling at some interfaces of Unite adhesive group and conventional etching+Transbond XT adhesive group, but the increase was not significant in any interface of TSEP group. With or without thermocycling, TSEP displayed more microleakage than other groups. In most groups, microleakage at gingival margin was significantly higher than occlusal margin. Thermocycling and type of bonding technique significantly affect the amount of microleakage.
    Keywords: Adhesive, microleakage, orthodontic bracket, thermocycling
  • Maryam Bidar, Azam Sadat Madani, Nooshin Mohtasham, Mandana Vardkar, Hamid Jafarzadeh Page 29
    Full crown preparation may have adverse effects on pulp tissue. In this study, the effect of full-crown preparation on intact versus inflamed pulp tissue was studied.
    Methods
    Fifteen healthy mature cats were randomly selected for this study. The study was performed on four canine teeth of each cat. Cats were anesthetized and then radiographs were taken from the canine teeth. Class V cavities were prepared in cat canine teeth. Soft decayed dentin was placed on the floor of cavities and sealed. After 1 month, all of the samples prepared for crown fabrication. Before crown preparation, an impression was taken in a custom tray. During crown preparation, the remnants of carious dentin were removed and undercuts were sealed by glass-ionomer. After preparation, self-cured acrylic temporary crowns were fabricated in a direct procedure and cemented permanently by glass-ionomer. One week later, teeth of the opposite jaw were prepared in a similar procedure. After 2 months, vital perfusion performed and the pulp tissue was histologically examined. There was no significant difference between 4 groups, regarding to histologic status of the pulp. In healthy lower jaw, inflammation was the most frequent but in the other groups, necrosis was most frequent. Also, there was no significant difference between the upper jaw and the lower jaw groups regarding to the frequency of necrosis and inflammation. There is no significant difference between intact and inflamed groups regarding the frequency of necrosis and inflammation
    Keywords: Animal study, chronic inflammation, crown preparation
  • Jahanshah Salehinejad, Atefeh Nasseh, Amir Hossein Jafarian, Nazanin Bashardoust Page 34
    Malignant peripheral nerve sheath tumor (MPNST) is a rare malignant tumor that develops either from a preexisting neurofibroma or de novo. The cell of origin is believed to be the Schwann cell and possibly other nerve sheath cells. In this report, we describe a rare case of MPNST that arise from the socket of second left maxillary molar that has been already extracted in a young man. He was referred to a dentist’s office with a tumor-like mass of soft tissue on his left maxillary gingiva. Biopsy and histopathologic examination was performed and based on histologic and immuno-histochemical findings, the diagnosis of MPNST was made. MPNST is a rare malignant tumor in the oral cavity. Dentists must be careful and conscious because this rare malignancy can occur in gingiva and can mimic the clinical feature of any benign gingival enlargements.
    Keywords: Malignant peripheral nerve sheath tumor, maxilla, neurofibroma