Journal of Dentistry, Shiraz University of Medical Sciences
Volume:14 Issue: 1, Mar 2013

Statement of Problem: Image distortion in intra and extra-oral radiographs are an unavoidable phenomenon. Patient''s positional changes from the routine alignments is an important issue for this unwanted alteration, Therefore the accuracy of the dimensional measurements will be affected. Our purpose is to find out the effect of minor changes (possibly happening in the clinic) in the position of a human dry skull on the accuracy of the measurements acquired by Cone Beam Computed Tomography (CBCT). In this study, 3 locations on the skull were pointed with radio- opaque markers. Imaging process with Kodak 9000 CBCT was performed in standard and 10 analytically miss- oriented positions. Then 2 distances were measured between the centers of markers. Later, these measurements were compared with the standard position values. There was not any imperative difference in the measurements of the 10 altered positions yielded in this study with standard position values. According to our results, apparently, the accuracy of linear measurements in CBCT images is endorsed by unintentional small changes in the patient’s position during the projections.

Statement of Problem: Dental procedures leading to oral tissue injuries may provoke bacterial release to the blood stream causing infective endocarditis (IE) in vulnerable patients. The guideline which was proposed by AHA has been updated 9 times having the last update published in 2007. This study was endeavored to uncover the level of knowledge of general dental practitioners in Shiraz, concerning the 2007 AHA guidelines for endocarditis prophylaxis in patients with cardiac problems receiving dental treatments. This cross- sectional and descriptive analytical study included 150 dentists as participants. All practitioners were given a self –report questionnaire which consisted of three sections. Questions were designed to assess their knowledge of antibiotic prophylaxis in patients with cardiac disease. Almost all participants (93%) were aware of antibiotic prophylaxis to be essential for tooth extraction. Most participants did not believe in prophylaxis for noninvasive procedures (such as shedding of primary teeth, impression, intraoral radiography). From all of the respondents, 75% considered Amoxicillin to be the antibiotic of choice and 57% were acquainted with the correct dose of Amoxicillin for high risk patients. The study identified a potential for under/over prescription of antibiotic prophylaxis under the current guideline. Burden of IE necessitates more accurate knowledge of antibiotic prophylaxis in the undergraduate curriculum and continuing education programs of dentistry.

Statement of Problem: The flexure of the fiber- reinforced composites (FRC) which can be generally used instead of fixed metal- framework prostheses have been more advocated due to the enormous demands for the conservative and esthetic restoration. The flexure of the fiber should be well-fitted to its covering composite. No study has been reported the comparison of the combination of glass and polyethylene fiber with particulate filled composite and fiber reinforced composite yet. This study compared the flexural strength of two types of fibers combined with three types of composites. Sixty-six specimens were prepared in a split mold (25×2×2 mm). The specimens were divided into six groups according to the type of resin and the fiber (N = 11): group 1: Z250 composite + Polyethylene fiber; group 2: Build It composite + Polyethylene fiber; group 3: Nulite F composite+ Polyethylene fiber; group 4: glass fiber + Z250 composite; group 5: glass fiber + Build-It composite and group 6: glass fiber + Nulite F. The mean flexural strengths (MPa) values were determined in a 3-point bending test at a crosshead speed of 1 mm/min by a universal testing machine (Zwick/Roell Z020, Germany). The results were statistically analyzed, using one and two- way ANOVA and LSD post-hoc tests (p< 0.05). The highest flexural strength was registered for glass fiber in combination with Z250 composite (500 MPa) and the lowest for polyethylene fiber in combination with Build-It composite (188 MPa). One-way ANOVA test revealed that there was no statistically significant difference between polyethylene fiber combinations (p= 0.62) but there was a significant difference between glass fiber combinations (p= 0.0001). Two-way ANOVA revealed that the fiber type had a significant effect on flexural strength (p= 0.0001). The choice of fiber and composite type was shown to have a significant positive influence on the flexural properties of the fiber-reinforced composite. Glass fiber has a significant influence on the flexural properties of directly- made specimens.

Statement of Problem: Deliberating the patients’ rights is one of the major human ethical and legal principles which can be investigated through the agenda of professional and medical ethics.accordingly, the students of dentistry have to be educated about this issue and achieve the necessary skills in deliberating and concerning the patients’ rights. The present study aimed to investigate Shiraz dental students’ awareness and attitude regarding the patients’ rights as well as the principles of dental ethics in order to design methods for organizing and improving the ethics in dentistry. The present descriptive-analytical study was conducted on 111 students of different departments of Shiraz Dental School. The study data were collected through a questionnaire designed based on the patients’ rights charter in Iran, ADA ethical codes which are internationally acceptable in the field of dentistry, and the guidelines of the ministry of health, treatment, and medical education (No. 140588). Then, the data were entered into the SPSS statistical software and analyzed. Of all participants, 21.6% were men and 78.4% were women. According to the results, 71% of the students were acquainted with the patients’ rights. In addition, the patients’ characteristics, including gender and nationality, were not important for 58.6% of the students. The study findings showed that 71% of the participants were acquainted with the patients’ rights Establishment of a comprehensive, integrated charter in Iran is needed. With rapid development of medical sciences, new issues appear which necessitate taking into account the mutual rights of the physicians, people, and patients.

Statement of Problem: Studies reported that nearly 60% of endodontic failures have been attributed to inadequate obturation of the root canal system. Thus, complete obturation of the root canal system and proper apical seal are essential elements in the long-term success of root canal treatment. This study aimed to compare the apical seal of lateral condensation technique in the room and in body- simulated temperature. In this experimental study, 70 extracted, single- rooted, human premolar teeth were instrumented and divided up into four groups. All tooth’s canals were obturated by lateral condensation technique except the teeth in the positive control group. Group 1and 2, each with 30 teeth, were obturated in the room and intracanal temperature respectively. The other two groups were positive and negative control group each with 5 teeth. All groups except negative control were covered by two layers of nail polish. Then linear dye penetration was evaluated with a stereomicroscope. Data was analyzed with student-t test and also Kolmogorov- Smirnov Goodness- of- Fit test to make sure of data. Results showed that dye penetration in group one (obturation in room temperature) was 0.6mm more than group 2 (obturation in simulated-body temperature) although this was not statistically significant (p> 0.05). Under the condition of this invitro study, apical sealing ability was better in the body-simulated temperature than the room temperature, although it was not statistically significant.

Statement of Problem: Sealing the perforation defect is an important factor to reduce inflammation in the area and to perform healing. Selecting the appropriate material to repair the defect is an important concern. Among the various available materials, MTA and CEM are used recently for achieving this purpose. In the current study we compare the sealing ability of these materials by evaluating their microleakage by fluid filtration method. The purpose of this study was to compare the microleakage of MTA and CEM cement in furcal perforation in different periods of time. Forty one mandibular molars were selected for this experimental study. The perforation defects were created perpendicular to the long axis of the teeth, on the furcation of the teeth and the samples were divided into 2 experimental and two control groups. The defects were sealed by CEM and MTA in each experimental group. The samples were undergone the fluid filtration test with 20 cm H2O pressure. The amount of fluid filtration was measured for each sample at 24, 72 and 168 hrs and the data were analyzed by using ANOVA and T test. The experimental groups which were sealed with CEM exhibited significantly less microleakage in all determined periods of time (24, 72 and 168 hrs) than MTA groups (p< 0.001). Based on the results of this study, CEM cement has a better sealing ability compared with MTA using fluid filtration method.

Statement of Problem: Carpal tunnel syndrome (CTS) is an important cause of work disability. There is controversy over the relation between carpal tunnel syndrome and occupation. The aim of this study was to assess the relationship between the time-span of practicing dentistry and the role of dominant hands in the development of carpal tunnel syndrome. In this descriptive cross sectional study, 40 dentists and dental students (15 women and 25 men) undertook the electroneuro-diagnostic test in both hands by an electromyogram (EMG) and they were also evaluated in terms of self- reported clinical symptoms. 17.5% of participants were diagnosed to have decreased nerve conduction velocity while10% had reported clinical symptoms of CTS. Both dominant and non-dominant hands were involved. Within cases who were diagnosed as having median nerve neuropathy, 87.5% worked more than 20 hours per week. 57% had 17-23 years of dental practice experience and 14.2% of cases had10-16 years of practice in dentistry. The high rate of CTS symptoms, in both dominant and non-dominant hand among dental practitioners with more years of dental practice, indicates a prequisite for particular attention, then sufficient education on the major risk factors causing this problem. Early diagnosis of these symptoms may improve the future management of the disease.

Odontogenic myxoma is a rare and locally invasive benign neoplasm found exclusively in jaws. It presents local invasiveness and tendency to recurrence. According to the World Health Organization (WHO), the odontogenic myxoma is classified as an odontogenic tumor of ectomesenchymal origin. The odontogenic myxoma is a rare entity found in both jaws while the mandible is involved more commonly than the maxilla. We present a kind of odontogenic myxoma in a 24-year old male that was found in an unusual location.

Mucocele and traumatic neuroma are two lesions related to the traumatic events; however there is only one reported case in which these two entities were perceived simultaneously. The current study reported a 21-year-old man who complained of painless recurrent swelling, accompanied by paresthesia on his left lower labial mucosa. He had a previous history of similar lesion and had been treated with surgery and cauterization last year. The primary clinical impression was a recurrent mucocele. Microscopic surveys displayed a traumatic neuroma in the vicinity of a mucocele which seems to be arising from the previous surgical treatment.

The American Academy of Orthopaedic Surgeons (AAOS) and the American Dental Association (ADA), along with 10 other academic associations and societies recently (December 2012) published their mutual clinical practice guideline “Prevention of Orthopaedic Implant Infection in Patients Undergoing Dental” Procedures.” This evidence-based guideline, detailed in 325 pages, has three recommendations and substitutes the previous AAOS guideline. The new published clinical guideline is a protocol to prevent patients undertaking dental procedures from orthopaedic implant infection. The guideline is developed on the basis of a collaborative systematic review to provide practical advice for training clinicians, dentists and any qualified physicians who need to consider prevention of orthopaedic implant (prosthesis) infection in their patients. This systematic review found no explicit evidence of cause-and-effect relationship between dental procedures and periprosthetic joint infection (PJI).This LTTE wishes to present a vivid summary of AAOS/ADA clinical practice guideline as a clinical update and an academic implementation to inform and assist Iranian competent clinicians and dentists in the course of their treatment decisions, to enrich the value and quality of health care on the latest international basis.