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Dental Materials and Techniques - Volume:4 Issue: 1, Winter 2015

Journal of Dental Materials and Techniques
Volume:4 Issue: 1, Winter 2015

  • تاریخ انتشار: 1393/10/14
  • تعداد عناوین: 8
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  • Saied Mostafa Moazzami, Berahman Sabzevari Pages 1-7
    Introduction
    Current Thermal cycling units fail to simulate the drinking behaviors, and oral balancing temperature. They cannot also simulate other oral conditions such as drink coloring, and chemicals like tea, coffee, carbonated and noncarbonated, citrus juices as well as alcoholic and nonalcoholic drinks and also saliva and milk itself. The main objective of this study is to introduce the designing and manufacturing the first Drinking Simulator Unit (DSU) that reproduces the thermal, color and chemicalcycling as well as the drinking behavior and oral temperature in lab conditions uniquely.
    Methods
    The invented system generally has two parts: the hardware and the software parts. The hardware consists of the mechanical and electronic parts. The software part is responsible for controlling the heating and cooling systems, electric valves, the pumps, and automatic filling systems of tanks as well as the sensors of the machine.
    Results
    DSU is the first unit can reproduce the thermal, color and chemical cycling as well as the drinking behavior and oral temperature in lab conditions. Different kinds of colored and acidic drinks and also other chemical materials such as bleaching substances as well as detergents and antiseptics used for dentistry, industrial and medical purposes can be tested by DSU. DSU has also to be considered as an appliance performing in-vitro researches on dental structures.
    Conclusion
    The invented system can greatly improve and validate the results of such researches.
    Keywords: Chemical cycling, color cycling, dentistry, drinking, simulator, thermal cycling
  • Abhinav Gupta* Pages 8-12
    Retrieving failed cemented crowns and fixed partial dentures with minimum discomfort to the patient has always been a clinical concern. This article describes a technique which will allow easy and predictable removal of these restorations.
    Keywords: Crown, fixed partial denture, retrievability
  • Nasrin Sarabi, Habib Taji, Javad Jalayer, Negin Ghaffari, Maryam Forghani* Pages 13-20
    Introduction
    The restoration of endodontically treated teeth is a topic that has been studied extensively but it is still a challenge for dental practitioners. The aim of this study was to evaluate fracture resistance, fracture patterns and fracture location of endodontically treated human maxillary premolars restored with direct and indirect composite resin and ceramic restoration.
    Methods
    Eighty non-carious maxillary premolars were selected and divided into four groups (n=20). Endodontic treatment and mesio-occluso-distal preparations were carried out in all the groups except for the control group (group I). Subsequently, the prepared teeth were restored as follows: group II: indirect composite restoration; group III: ceramic restoration; group IV: direct composite restoration. The specimens were subjected to compressive axial loading until fracture occurred. The mode of failure was also recorded.
    Results
    Group I had higher fracture resistance (1196.82±241.74) than the other groups (P<0.05) and group IV exhibited significantly higher values (962.10±165.52) compared to groups II (731.21±85.89) and III (758.18±108.10) (P<0.05). The fracture patterns were significantly different between the composite resin groups and the ceramic group (P<0.05). The most prevalent fracture pattern in the groups II and IV was mixed fracture and in the group III, restoration cohesive fracture was the predominant pattern. With regard to fracture location, the direct composite restorations exhibited more fractures below the CEJ compared to the indirect restorations (P<0.05).
    Conclusions
    Use of direct composite restorations resulted in higher resistance against fracture, but their failure modes may be unfavorable
    Keywords: Direct composite, endodontically treated teeth, indirect restorations, premolars, tooth fracture
  • Zahra Shakibaei, Elahe Tohidi*, Fatemeh Salemi, Samira Saati Pages 21-28
    Introduction
    The aim of this study was to investigate the prevalence of stylohyoid ligament complex elongation in a group of Iranian patients using digital panoramic radiographs.
    Methods
    Panoramic radiographs of 1211 patients (684 females and 527 males) referred to the dental school of Hamadan university of medical science were selected from 2011 to 2013. The stylohyoid ligament complexes were investigated.
    Results
    This abnormality was seen in both sexes. A calcified complex was found in 632 (52.2 %) of the patients. Both-sided (right and left) type 1 calcified complex (according to O’Carroll classification) was observed in 207 patients, while types 2–4 were found in 204, 112, and 109 patients, respectively.
    Conclusion
    The results suggest that stylohyoid ligament calcification complex is frequent in Iranian population and present in both sexes with equal distribution. In addition, calcifications were seen more often at age of 20-40 years, and the extent of calcification did not show a tendency to increase with age.
    Keywords: Elongated styloid process syndrome, stylohyoid ligament calcification, panoramic radiograph
  • Farnaz Fattahi, Rashin Giti, Kianoosh Torabi Pages 29-35
    Introduction
    Marginal adaptation is the most critical item in long-term prognosis of single crowns. This study aimed to assess the marginal quality as well asthe discrepancies in marginal integrity of some PFM single crowns of posterior teeth by employing parallel radiography in Shiraz Dental School, Shiraz, Iran.
    Methods
    In this descriptive study, parallel radiographies were taken from 200 fabricated PFM single crowns of posterior teeth after cementation and before discharging the patient. To calculate the magnification of the images, a metallic sphere with the thickness of 4 mm was placed in the direction of the crown margin on the occlusal surface. Thereafter, the horizontal and vertical space between the crown margins, the margin of preparations and also the vertical space between the crown margin and the bone crest were measured by using digital radiological software.
    Results
    Analysis of data by descriptive statistics revealed that 75.5% and 60% of the cases had more than the acceptable space (50µm) in the vertical (130±20µm) and horizontal (90±15µm) dimensions, respectively. Moreover, 85% of patients were found to have either horizontal or vertical gap. In 77% of cases, the margins of crowns invaded the biologic width in the mesial and 70% in distal surfaces.
    Conclusion
    Parallel radiography can be expedient in the stage of framework try-in to yield some important information that cannot be obtained by routine clinical evaluations and may improve the treatment prognosis
    Keywords: Marginal adaptation, metal, ceramic crowns, radiography
  • Mahshid Sheikh, Nezami, Majid Akbari, Khosro Shamsian, Samaneh Vasigh, Armita Rouhani* Pages 37-41
    Introduction

    Traumatic dental injuries (TDI) in children and adolescents are a common dental health problem and the prevalence of these injuries has increased during the past few decades. The aim of this paper was to evaluate the data of the patients with dental trauma in permanent teeth looking for treatment in the Dental Trauma Clinic in the North-east of Iran over 4 years.

    Methods

    During the period April 2008 –March 2012 a total of 341 patients presented with dental trauma in the Dental Trauma Clinic; of these, 323 records had the inclusion criteria for further evaluation.

    Results

    Dental records of 323 patients were analyzed, 727 teeth were affected. The numbers of male and female were 217 and 106, respectively. There was a significant difference between genders (P<0.05). Ages ranged from 7 to 68 years; the most frequent ranged between the ages of 8-12 years. The most commonly affected tooth was maxillary central incisor and two traumatized teeth were more prevalent than one. The most common type of dental injuries was lateral luxation. The most common cause of TDI was falling due to the road accident, fighting, sport activities and playing, collision with objects and bicycle crash. There was no significant difference in occurrence of TDI according to the seasons.

    Conclusion

    TDI in permanent dentition should receive careful attention, because it occurred frequently at a young age and due to complexity of TDIs, every dental clinic should have a continuous registration of number, type and severity of TDIs.

    Keywords: Dental trauma, fracture, Iran, luxation, permanent dentition
  • Alireza Boruziniat, Noushin Arjmand, Atefeh Atoufi Pages 43-47
    Introduction
    To evaluate the effects of using sodium hypochlorite irrigant on pull-out bond strength of self-etch and self-adhesive resin cements to dentin.
    Methods
    Sixty intact premolars were decoronated and the root canals were prepared by step-back technique. The teeth were divided into two groups according to the irrigant used during root canal treatment: 5.25% sodium hypochlorite and normal saline. The canals were obturated and after 48 hours storage, 8mm depth post space was prepared with application of normal saline as irrigant. Then, each group was divided into two subgroups depending on the type of the cements used for cementation of fiber reinforced composite (FRC) posts (Panavia F2or Embrace). The pull-out bond strength test was evaluated. Statistical analysis was performed by Two-way AONVA.
    Results
    The type of cement had no statistically significant effect on the bond strength; however, the type of irrigant was statistically effective. There was no interaction between two independent variables. The application of sodium hypochlorite significantly decreased the pull-out bond strength in Embrace cement in comparison with the use of normal saline.
    Conclusion
    The type of irrigants used in endodontic treatment may affect on bond strength of FRC posts cemented by self-adhesive cements.
    Keywords: FRC post, pull, out bond strength, resin cement, sodium hypochlorite
  • Hamid Reza Arab, Amir Moeintaghavi, Majid Reza Mokhtari*, Fatemeh Farazi, Amirtaher Mirmortazavi Pages 49-55
    Careful treatment planning, space management, augmentation of bone and attention to the details of implant surgical and prosthetic techniques are important factors when treating anterior maxilla specially replacement of missing teeth. This case report addresses a chair-side ridge augmentation procedure using autograft bone harvested with trephine drills and placed without using screws and the fundamental considerations related to replacement of a congenitally missing lateral incisor by a team approach
    Keywords: Case report, dental implant, lateral incisor, ridge augmentation procedure