Frontiers in Dentistry
Volume:10 Issue: 6, Nov 2013

Renal transplantation is performed in patients with end stage renal disease as the best treatment plan. However, different complications may occur in these patients due to the direct consequences of the renal disease or drug-induced suppression of the body immune system. The main objective of the present study was to compare different oral lesions in patients receiving renal transplantation with the patients undergoing dialysis referred to two hospitals in Tehran, Iran. In this cross -sectional study, 93 renal transplant patients who had received renal transplant at least 6 months prior to our study, were selected from their records at the hospitals. Furthermore, 93 candidates of renal transplantation were selected as the control group. The patients in both case and control groups underwent oral examinations and the results were analyzed by chi-square test and Spearman correlation coefficient. At least one oral lesion was found in 30 (32.2%) patients in the renal transplant group and 8 (8.6%) patents in the control subjects. The difference between the two groups was statistically significant (p<0.0001). The most prevalent lesion was xerostomia observed in 20 patients of the renal transplant group and 4 patients in the control group. The odds ratio of cyclosporine and amlodipine and the effect of these in increasing the risk of oral lesions was 1.21 and 1.02, respectively in renal transplant recipients. The results of the study showed that renal transplantation significantly increases the risk of related oral lesions. Therefore, renal transplant recipients must undergo regular oral examinations in order to find any suspicious lesion(s) as soon as possible to treat them.

The release of toxic metal ions from orthodontic alloys has induced concerns regarding the biocompatibility of fixed appliances. This study investigated the genotoxic effect of metal appliances in a sample of patients undergoing fixed orthodontic treatment. The study included twenty-five healthy individuals requiring orthodontic therapy in both jaws. The patients were treated by stainless steel orthodontic brackets and nickel-titanium or stainless steel arch wires. The oral mucosa cells were gathered just before the appliance placement and 9 months later. The cells were centrifuged, fixed and dropped onto slides. After staining, the micronucleus (MN) assay was used to determine genome alteration. The data were analyzed by paired sample t-test. The mean micronuclei frequency in the buccal mucosa was 10.6 ± 5.7 per 1000 cells before the appliance placement and 9.2 ± 6.37 per 1000 cells 9 months later. No significant difference was found in the MN count before and 9 months after therapy (p=0.336). Under the conditions used in this study, application of fixed orthodontic appliances did not expose healthy individuals to increased risk of DNA damage in oral mucosa cells.

The aim of this in-vitro study was to compare the accuracy of two new electronic apex-locator controlled handpieces (EALHs) using the first rotary Mtwo file while rotating in the canal. A total of 36 extracted mandibular molar teeth were selected. The lengths of the mesio-buccal canals to the major foramina were measured directly using a size 10 K-file introduced in the canal until the tip was visible under a loupe and then 0.5 mm was subtracted from the recorded lengths as the actual working lengths (AWLs). Subsequently, the teeth were randomly assigned to two groups and embedded in an alginate model. Auto-stop function of the EALHs was preset at ‘‘0.5’’ mark and then electrical working lengths (EWLs) in groups 1 and 2 were recorded by VDW GOLD and Dentaport ZX, respectively. Analysis of variance (ANOVA, 1-way) and Tukey pairwise multiple comparison intervals (0.05) were used to compare the accuracy of the two electronic devices. For VDW GOLD, 61.1% of the measurements were within ±0.5 mm and 88.9% were within ±1 mm of the AWL. For Dentaport ZX, 88.9% of the measurements were within ±0.5 mm and 94.4% were within ±1mm of the AWL. There was no significant difference between AWLs and EWLs (p=0.466 for Dentaport ZX and p=0.283 for VDW Gold) and between the accuracy of the two devices in determining the EWL (p=0.8). Both Dentaport ZX and VDW Gold were suitable for determining working length using a rotary file. To avoid over instrumenting the canal, we recommend setting the devices to automatically stop or reverse the rotary file at 1 mm level.

Little is known about the interaction of tissue conditioners and modeling plastics.This study evaluates the influence of a variety of commercial tissue conditioners on alteration of viscoelastic properties of modeling plastics. In this in vitro study, the dynamic viscoelastic properties of four commercially available tissue conditioners (TC), Visco-gel (VG), GC Soft-Liner (SL), FITT (FT), and Coe Comfort (CC), relined to modeling plastics with a thickness of 2mm were evaluated after 1 and 7 days of water immersion with the use of storage modulus, loss modulus, and tan delta parameters. Values for these three parameters for each tissue conditioner were statistically analyzed by Kruskal Wallis and Mann Whitney tests with P value sets at<0.05. Complex modulus and loss tangent values of TC were not significantly different among specimens containing 0, 2, 5 and 10 wt.%-SZ, respectively. In FT and TC containing 2 wt.%-SZ, these values were not significantly different between 1 and 28 days in both water- and saliva immersions. The results suggest that relining with modeling plastics does affect TC’s inherent dynamic viscoelastic properties, while the other tissue conditioners investigated may be found to have changed viscoelastic properties as a consequence of vicinity to the modeling plastics.

A detailed knowledge of root canal anatomy is a prerequisite for successful endodontic treatment. Such information is highly dependent upon the ethnicity of the population of interest. Lack of sufficient national information concerning internal anatomy can lead clinicians to increase their rate of treat-ment success. The aim of this study was to evaluate external root morphology and root canal anatomy of mandibular second premolars in an Iranian popula-tion. Two hundred seventeen human extracted mandibular second premolars were selected. Each tooth was radiographed both mesiodistal-ly and buccolingually. Then, access cavities were prepared for each tooth and root canal negotiated before being immersed into 1% fuchsine solution. Teeth were de-coronated and their roots sectioned into three equal (cervical, middle and apical) parts. Cross sections were visualized under 40X magnification. Among all roots examined, 132 were straight both mesiodistally and buccolingually, 56 were mesiodistally curved, but buccolingually straight, 11 were mesiodistally straight, but buccolingually curved and 18 samples were curved in both aspects. Internal anatomical evaluation showed 198 samples (91.24%) with a single and 19 (8.75%) with more than one canal. Although straight roots are common in mandibular second premo-lars, curvatures in mesiodistal, buccolingual or both directions are not uncom-mon in the Iranian population. Single-canalled roots are also frequent in these teeth, but Vertucci’s types II, III, IV, V, and C-shaped configurations are also encountered.

Dental arch form is one of the most important characteristics of dentition. However, this dimension usually receives less attention in diagnosis or treatment planning and orthodontic patients are traditionally classified with regard to their sagittal characteristics. The objectives of this study were to investigate if a relationship exists between the dental arch width (transverse dimension) and sagittal skeletal and dental parameters in orthodontic patients. Dental casts and lateral cephalograms of 108 consecutive untreated Iranian patients (47 males and 61 females) between 16 and 31 years of age were evaluated. Arch width (AW) parameters including upper and lower inter-molar width (UIMW and LIMW) and upper and lower inter-canine width (UICW and LICW) were measured by a digital caliper. Sagittal parameters included SNA and SNB angle and Wits’ appraisal obtained from lateral cephalograms in addition to upper and lower arch length (UAL and LAL) obtained from dental casts. The correlation between the aforementioned parameters was evaluated applying Pearson correlation coefficients. Molar and canine relationship according to Angle’s classification was also recorded and the means of all parameters were compared between three occlusal relationship classes and two gender groups by means of two-way ANOVA. According to statistical analysis a significant positive correlation between sagittal parameters and arch width measures exists between SNA and UICW and between LICW and LAL. Upper and lower ICW were significantly correlated, the relationship between upper and lower IMW and between UAL and LAL were significant. Among sagittal measures, both UAL and LAL were correlated with the ANB angle. The means of arch width parameters in three occlusal classes were not significantly different. The only significant correlation between arch width and sagittal parameters existed between UICW and SNA angle and between LICW and LAL. No significant difference of the arch width parameter was observed between the three occlusal classes.

Statins are used as cholesterol-lowering drugs by many patients and have been recently shown to affect bone metabolism. The aim of this study was to determine the effect of atorvastatinon on orthodontic tooth movement (OTM) in rats. Thirty-six adult male Sprague-Dawley rats were randomly divided into three groups of 12 samples each. Group A, served as control with no medication while groups B and C received a daily gavage of carboxymethyl cellulose (CMC) as vehicle and atorvastatin (5 mg/kg) as test substance, respectively. In all three groups, 6mm nickel-titanium closed-coil springs were ligated between the maxillary incisors and first left molars to deliver an initial force of 60g. Tooth movement was measured following sacrifice, 21 days after appliance insertion. Root resorption, PDL width and osteoclast number were histologically evaluated and compared between the groups. The mean amount of tooth movement was 0.62 mm in group A, 0.59 mm in group B and 0.38 mm in group C. OTM reduction following administration of atorvastatin was statistically significant (p<0.05), but there was no significant difference in the studied histologic variables among the three groups (p>0.05). According to the results obtained in the current study, atorvastatin appears to reduce tooth movement in rats; however its effect on osteoclasts, especially osteoclastic function, requires further investigation.

This study compared the push-out bond strength of EndoSequence Root Repair Material (ERRM) and Bioaggregate (BA), new bioceramic materials, to that of mineral trioxide aggregate (MTA) after incubation in phosphate-buffered saline (PBS), a synthetic tissue fluid, for either 1 week or 2 months. One-hundred and twenty root sections were filled with ProRoot MTA, BA, or ERRM. Each tested material was then randomly divided into two subgroups (n = 20): root sections were immersed in PBS for 1 week or 2 months. The bond strengths were measured using a universal testing machine. After that, the failure modes were examined with stereomicroscopy and scanning electron microscopy (SEM). The push-out data and failure mode categories were analyzed by two-way ANOVA and chi-square tests, respectively. The bond strength of ERRM was significantly higher than that of BA and MTA at both incubation periods. No significant difference was found between the bond strength of MTA and BA at either 1 week or 2 months. Increasing the incubation time to 2 months resulted in a significant increase in bond strength of all the materials. The failure mode was mainly mixed for MTA and BA, but cohesive for ERRM at both incubation periods. ERRM had significantly higher bond strength to root canal walls compared to MTA and BA. Increasing the incubation time significantly improved the bond strength and bioactive reaction products of all materials.

To compare the mechanical properties of Resilon and gutta-percha cones after storing at three different temperatures. One-hundred standardized size 40/02 gutta-percha cones and 100 Resilon cones were randomly divided into four groups. The first group of the materials were tested immediately after receipt as the control group. The other three were stored in their packages at -12°C, 4± 1°C and 22± 2°C for three months. Then, obturating cones were loaded by a tensile force at the rate of 5mm/min. Physical integrity of gutta-percha and Resilon cones were also evaluated according to ISO6877. The data were analyzed by one-way analysis of variance, post hoc and t-test. A p-value <0.05 was considered significant. The elasticity modulus of gutta-percha reduced significantly after three months storage at -12°C, while storage at 4±1°C and22± 2°C had no effect on its modulus of elasticity. In addition, the tensile strength of gutta-percha did not change after three months of storing. The modulus of elasticity of Resilon reduced significantly in all storage conditions; however, its tensile strength did not change. The storage conditions did not have a significant effect on the elongation rate of gutta-percha and Resilon. Eighty percent of gutta-percha cones lost their physical integrity after storage in 4 °±1C and 22±2°C. However, storage conditions had no impact on the physical integrity of Resilon cones. Storing gutta-percha at -12°C can benefit its properties, while keeping Resilon at both refrigerated and room conditions can preserve its mechanical properties.

Isolated impacted supernumerary teeth are quite rare, but they can be seen associated with several syndromes such as cleidocranial dysostosis or Gardner’s syndrome. This article aims to discuss a case of sequential formation of supernumerary teeth with no other associated disease or syndrome. A 17-year-old Iranian male with 8 impacted supernumerary teeth was referred to the department of pediatric dental clinic at Shahid Beheshti Medical University in Tehran with a history of several impacted unerupted teeth. Repeated and periodical clinical and radiographic examinations revealed newly formed teeth buds in unusual dental ages. All extra teeth were associated with generalized enamel hypoplasia to some degree on their relative permanent adjacent teeth. The patient did not have any record of a systemic disease or any syndromic condition to relate his dental problem to. This rare condition involved repeated and continued formation of extra teeth out of the normal numbers and dental age evident in serial radiographs.

Sinonasal undifferentiated carcinoma is an extremely rare malignancy of the paranasal sinuses and nasal cavity. It is of unknown etiology, and occurs more commonly in the elderly men, with a routinely shown aggressive behavior and poor prognosis for survival. Radiographically, it looks like severe osteomyelitis. Histopathologic study is essential to confirm diagnosis, and the undifferentiated histologic appearance often necessitates immunohistochemical studies for differentiation from other high-grade neoplasms. We present an 83-year-old man complaining of pain and unilateral swelling on the left side of the face due to a rare malignant tumor of maxillary sinus origin, a sinonasal undifferentiated carcinoma. He underwent hemimaxillectomy and radiotherapy, but refused chemotherapy. Maxillary sinus malignancy may be presented with unspecific symptoms mimicking sinusitis or dental pain. Coming across such symptoms, the physician or dentist must consider malignancies as well, and carry out medical and dental workups.

Dental anatomical variations play a significant role in the diagnosis and a success-ful treatment outcome in endodontics. It is essential for the clinician to have a clear picture and understanding of the pulpal anatomy and its variations. In a mandibular second premolar, it is rare to find extra roots and canals. The aim of the present article is to report a case about the successful diagnosis, and clinical management of a three-rooted mandibular second premolar with three indepen-dent roots and canals.