مجله دانشکده دندان پزشکی اصفهان
سال یازدهم شماره 1 (پیاپی 48، فروردین و اردیبهشت 1394)

Calcium hydroxide is used as an intracanal medicament in endodontics. Its therapeutic effects depend on the dissociation of calcium hydroxide into calcium and hydroxide ions. The aim of this study was to evaluate the pH and calcium ion concentration of three different calcium hydroxide pastes, after 24 hours and 1 week for each vehicle, on the external root surface. In this experimental study, the crowns of 72 human single-rooted teeth were removed, the canals were prepared and external defects were created on the root surfaces. All the surfaces except the external defects were sealed and the teeth were immersed in normal saline solution. The samples were divided into 6 experimental and 2 control groups. Experimental groups were dressed with calcium hydroxide in combination with: A and B: 0.2% chlorhexidine solution, B and C: 5.25% sodium hypochlorite solution, E and F: distilled water. Calcium ion concentrations and pH of normal saline solution were determined after 24 hours in groups A, C and E, and after one week in groups B, D and F. One-way and two-way ANOVA were used for statistical analysis with SPSS software program (α=0.05). In relation to pH, after 1 week there was a significant difference between groups B and D (p value = 0.013); the effect of time was significant in all the groups except for groups D and C (p value < 0.05). Calcium ion concentration at 24-hour and 1-week intervals was significant for each vehicle (p value < 0.001) but it was not significant between different groups (p value > 0.05). As an intracanal medication, the combination of 0.2% chlorhexidine and calcium hydroxide exhibited significantly higher pH values compared to the combination of 5.25% sodium hypochlorite and calcium hydroxide after one week. Calcium ion concentration increased after 1 week in all the groups; however, there were no significant differences in each group between the two time intervals.

Pain and complications are common after surgical removal of impacted third molars. The present study was undertaken to evaluate the effect of an oleous suspension of calcium hydroxide (OSTEORA) on pain severity and complications after surgical removal of impacted third molars. This clinical trial evaluated 30 patients with an age range of 17‒40, referring to a maxillofacial surgery department and two private clinics in Tehran in 2011‒2012 for surgical removal of bilaterally impacted third molars with the same difficulty index. OSTEORA was used on one side and no material was used on the contralateral side as the control. The effect of OSTEORA was evaluated on pain, healing, hemorrhage, dry socket and infection at different postoperative intervals in a double-blind manner. Data were analyzed with chi-squared and Mann-Whitney U tests (α=0.05). Of 60 samples, 28 were from the maxilla and 32 were from the mandible. Intensity of pain in the study groups at baseline and at follow-up intervals was the same (p value = 0.4). The incidence of hemorrhage at follow-ups was the same in both groups (p value < 0.5). Maxillary healing rates on the 3rd postoperative day in the control and test groups were 3.21±2.39 and 2.42±2.17, respectively (p value < 0.03) and on the 7th postoperative day they were 2.9±2.58 and 2.14±2.28, respectively (p value < 0.03). Healing in mandible in both groups was the same at follow-ups (p value < 0.2). No dry sockets and infection were observed in any subject. Under the limitations of the present study, use of an oleous suspension of calcium hydroxide had no effect on the incidence of hemorrhage and pain after surgical removal of impacted third molars. However, it affected healing of the surgical site, especially in the maxilla.

Studies have shown that failure in achieving anesthesia in the posterior mandibular teeth with irreversible pulpitis is common. Different factors have been reported to be responsible for failure of anesthesia in such teeth. The aim of the current study was to evaluate the effect of tooth length on failure rate of inferior alveolar never block anesthesia in mandibular first and second molars.

In this random cross-sectional study 90 patient with their first and/or second mandibular teeth affected with irreversible pulpitis were evaluated. Inferior alveolar nerve block anesthesia procedure was carried out with 2% lidocaine with 1:100000 epinephrine. Heft-parker Visual Analog Scale (VAS) was used for evaluation of pain. Lip anesthesia and absence of response to maximum pulp tester provocation after 15 minutes was considered as anesthesia. Pain was scored before treatment, during access cavity preparation and after pulp exposure. Tooth length was measured with endodontic gauge on periapical radiographs (SPSS) Data were analyzed with repeated-measures ANOVA, t-test and regression analysis, using SPSS 21 (α=0.05).

The total failure rate of inferior alveolar nerve block injection was 62.22%. The mean tooth lengths in patients with successful and failed inferior alveolar nerve blocks were 21.45±2.04 and 23.05±2.43 mm, respectively (p value = 0.002).

Under the limitations of the current study, it was concluded that tooth length might be a factor affecting the failure of inferior nerve block anesthesia technique.

Frontal sinus and nasal septum have different forms in different people. Frontal sinuses are different in shape even in monozygotic twins. The aim of this study was to determine the prevalence of different combined patterns of frontal sinus and nasal septum in men and women referring to a treatment center in Isfahan. In this descriptive/analytical study Water’s views of 198 subjects aged 20‒40 were collected. The particulars of frontal sinuses in relation to the presence or absence of the sinus proper, symmetry or asymmetry, the form of the septum and the superior border outline of the sinus and the form of the nasal septum were evaluated and recorded. Data were analyzed with chi-squared test (α= 0.05). Bilateral presence of frontal sinus was observed in 100% of the subjects. There were no relations between sex and the presence of a septum within the frontal sinus (p value = 0.53), sinus symmetry (p value = 0.35), and form of the nasal septum (p value = 0.89). There was a significant relation between sex and the presence of a scalloped superior border outline of frontal sinuses (p value < 0.05), with more scalloped borders in men compared to women. Under the limitations of the present study, it was concluded that the combined patterns of frontal sinuses and nasal septa on radiographs cannot be used to distinguish males from females.

Patient's motivation and orthodontic clinician's opinion are effective factors in decisions to initiate orthodontic treatment. Understanding motivations, maintaining them and enhancing them, if necessary, are crucial for successful orthodontic outcomes. The aim of this study was to investigate motivations and tendencies toward orthodontic treatment in patients with malocclusion referring to professional care centers in Isfahan in 2013. In this analytical cross-sectional study, a valid and reliable questionnaire was used to elicit information from 180 patients aged 15‒25. The questionnaire included demographic section, patient's motivation for and barriers to orthodontic treatment. Data were analyzed with descriptive, non-parametric and chi-squared tests using SPSS 16 (α=0.05). The patients’ level of motivation was determined as high (2.4±0.4). Aesthetic motivation gained the highest scores (2.8±0.4), followed by functional (2.4±0.4) and social motivations (2.3±0.6). The overall level of motivation and functional motivation were significantly higher in males compared to females (p value < 0.05). Tendency toward orthodontic treatment was at a moderate level, with no significant gender differences (p value = 0.73). The first and second most important sources of motivation were the patients themselves and parents’ advice, respectively. 77.1% and 14.1% of patients reported cost and long treatment duration as the main barriers to orthodontic care. This study showed that the overall motivation of patients for orthodontic treatment was high and aesthetics was the most important aspect of motivation. Further studies are recommended to evaluate personal motivation in relation to the type and severity of malocclusion.

Nowadays Ni-Ti rotary files have many advantages and are totally accepted in endodontic treatment. Sterilization of Ni-Ti rotary files is essential due to their frequent clinical use. The aim of this study was to evaluate the surface characteristics of M-two rotary files before and after autoclaving with scanning electron microscopy (SEM).

Ten #25 new M-two Ni-Ti rotary files (VDW, Munich, Germany) with 0.06 taper were analyzed with scanning electron microscopy under two magnifications of ×200 and ×1000 before and after 1, 5 and 10 autoclave cycles in this experimental prospective study. Scanning electron microscopic images were inspected in relation to surface changes, including the presence of millings, debris and surface irregularities. Paired-sample t-test was used for data analysis with SPSS 22 (α=0.05).

Scanning electron microscopy measurements showed cavities, debris and surface irregularities on specimens of both file groups, in the as-received condition and after sterilization. Surface irregularities and corrosion increased significantly after 10 autoclave cycles (p value = 0.001).

The results showed that after multiple autoclave cycles, debris, holes and surface corrosion increased significantly. These surface imperfections were proportional to the number of autoclave cycles and single autoclave cycle seemed to have a less detrimental effect on rotary files. However, multiple autoclave cycles increased surface irregularities progressively. The results showed inherent Ni-Ti rotary file limitations in clinical usee and after multiple sterilization cycles.

Accurate estimation of blood loss for predicting the need for transfusion during bimaxillary orthognathic surgery is important for maxillofacial surgeons and anesthesiologists. The aim of the present study was to determine blood loss in subjects who underwent maxillofacial orthognathic surgery in terms of age, gender and operative time. The present descriptive study was carried out in Chamran Hospital, Shiraz University of Medical Sciences, from 2011 to 2012. A total of 68 patients were selected using convenient sampling technique. Patients with smoking habits and addiction to opioids and those using medications affecting coagulation were excluded. All the surgeries were performed by the same surgical team under controlled hypotensive general anesthesia and infusion of tranexamic acid. Surgical blood loss was measured by counting the number of gauze pads saturated with blood and the amount of blood in the surgical suction unit. Data were analyzed with descriptive statistical methods at α=0.05. The study sample consisted of 61 subjects (25 males and 36 females) with a mean age of 23.7±5.9 years and average weight of 60.2±12.2 kg. All the subjects completed the study. The average surgical blood loss was 525.1±223.1 mL and the average operative time was 246.9±52.5 minutes. The average surgical blood loss for women and men were 465.8±161.6 and 610.4±271.0 mL, respectively, during a mean operative time of 255.8±54.9 minutes. The correlation coefficient between blood loss and operative time was 0.62 (p value < 0.05), demonstrating an increase in blood loss with a increase in operative time. Based on the results of this study, there was greater intraoperative blood loss only in patients with longer operative time. It is suggested that this factor be taken into account for estimating the amount of blood lost and prediction of the need for replacing lost blood.

Knowledge about pulp status is necessary before any dental intervention. Teeth associated with alveolar cleft are believed to have a different blood supply and innervation. The aim of this study was to determine and compare the pulp vitality of bilateral maxillary canines in a group of patients with unilateral alveolar cleft after alveolar bone graft surgery by pulse oximetry, electric pulp testing (EPT) and cold test.

In this random descriptive cross-sectional study, after evaluation of maxillary canines in almost 70 patients with unilateral alveolar cleft who had undergone secondary bone graft surgery, 20 patients were selected by applying the inclusion criteria. Pulp vitality of the teeth was evaluated by pulse oximetry, EPT and cold test. Data were analyzed with t-test, and Mann-Whitney and chi-squared tests (α=0.05).

The mean pulp blood flow saturation in maxillary canines was 85.04±4.65 on the cleft side and 87.78±4.01 on the normal side and the difference was significant (p value = 0.05). In the cold test investigation on maxillary canines, 13 subjects (65%) had ++ and 7 (35%) had + responses on the cleft side; on the normal side 7 subjects (35%) had ++ and 13 (65%) had + responses, with no significant differences between the two sides (p value = 0.06). Mean responses to EPT were 5.6 and 5.8 on the cleft and normal sides, respectively, with no statistically significant differences (p value = 0.62).

Based on the results of this study, pulse oximetry might be more reliable than electric pulp testing and cold test in the evaluation of pulp vitality in patients with alveolar cleft.

In recent decades, pit and fissure sealants have been introduced to dentistry as an effective clinical method for prevention of pit and fissure caries. Since only a limited number of studies have been carried out on hydrophilic fissure sealants, this experimental study was undertaken to compare microleakage of a hydrophilic fissure sealant with that of a conventional fissure sealant in vitro in an isolated saliva-contaminated environment. In this in vitro study, 64 extracted mandibular third molars with no decay, fillings and cracks were selected and divided into 4 groups randomly. The teeth in groups 1 and 2 were treated with Clinpro conventional sealant in isolated and saliva-contaminated environments, respectively. The teeth in groups 3 and 4 were treated with Smartseal & Loc hydrophilic sealant in isolated and saliva-contaminated environments, respectively. After thermocycling, the samples in each group were separately immersed in 0.5% fuchsin solution. Then the samples were sectioned buccolingually. Microleakage was studied under a stereomicroscope at a magnification of ×24. Kruskal-Wallis and Mann-Whitney tests were used for analysis of data (α=0.05). The minimum and maximum microleakage means were observed in groups 1 and 2, respectively. Statistically there was no significant differences in microleakage between groups 1 and 3 (p value = 0.61) and groups 2 and 4 (p value = 0.84), whereas there were significant differences between groups 1 and 2 (p value < 0.001) and groups 3 and 4 (p value < 0.001). Under the limitations of the present study, hydrophilic fissure sealants do not appear to be superior to conventional hydrophobic fissure sealants in relation to microleakage.

Digital radiography systems can be used to detect dental caries. These systems have the advantage of reducing patient dose. The purpose of this study was to compare digital photostimulable phosphor plate, charge coupled device and cone-beam computed tomography systems in detection of interproximal demineralization.

In this cross-sectional analytical laboratory study, sixty extracted human teeth with sound mesial and distal surfaces were selected. Using a ¼ round bur (0.5 mm in diameter) cavities were prepared to a depth of 0.25 mm just apical to the interproximal contact point on 15 surfaces of teeth. A ½ round bur (0.6 mm in diameter) was used to prepare cavities to a depth of 0.3 mm on 15 surfaces and a #1 round bur was used to prepare cavities 0.4 mm in depth on 15 surfaces. The teeth were mounted in groups of three in wax blocks. The images were captured by digital CBCT, PSP and CCD systems under a standard condition. One oral radiologist observed the images to detect interproximal defects twice three weeks apart. Then, sensitivity and specificity were calculated and Cochran test was used for statistical analysis with SPSS 20).α=0.05).

The sensitivity rates of CBCT, PSP and CCD systems for the detection of lesions measuring 0.25 mm in depth (incipient caries) were 100%, 93.3% and 86.7%, respectively (p value = 0.22); there was no differences between the systems in the detection of deeper lesions (100%). There was a high agreement rate between the radiographic systems evaluated and the gold standard in the detection of lesions with varying depths (CCD=94.4% and CBCT/PSP=100%). Specificity of all the systems was 100%.

Under the limitations of this study, there were no significant differences between CBCT, PSP and CCD digital radiographic systems in the detection of interproximal demineralization. The specificity of all the three systems was the same.