Vol 13, No 2 (2016)

Published: 2016-10-10

Original Article

  • XML | PDF | downloads: 238 | views: 331 | pages: 73-76
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    Objectives: This study sought to assess the diagnostic accuracy of cone beam computed tomography (CBCT) with different voxel sizes and intraoral digital radiography with photostimulable phosphor (PSP) plate for detection of periapical (PA) bone lesions.
    Materials and Methods: In this ex vivo diagnostic study, one-millimeter defects were created in the alveolar sockets of 15 bone blocks, each with two posterior teeth. A no-defect control group was also included. Digital PA radiographs with PSP plates and CBCT scans with 200, 250 and 300μ voxel sizes were obtained. Four observers evaluated the possibility of lesion detection using a 5-point scale. Sensitivity, specificity, positive predictive value (PPV) and negative predicative value (NPV) were analyzed using one-way ANOVA and Tamhane’s post hoc test. Kappa and weighted kappa statistics were applied to assess intraobserver and interobserver agreements.
    Results: Cochrane Q test showed no significant difference between PSP and CBCT imaging modalities in terms of kappa and weighted kappa statistics (P=0.675). The complete sensitivity and complete NPV for 200 and 250 μ voxel sizes were higher than those of 300 μ voxel size and digital radiography (P<0.001). No significant difference was noted in other parameters among other imaging modalities (P=0.403).
    Conclusions: The results showed that high-resolution CBCT scans had higher diagnostic accuracy than PSP digital radiography for detection of artificially created PA bone lesions. Voxel size (field of view) must be taken into account to minimize patient radiation dose.

     

  • XML | PDF | downloads: 278 | views: 395 | pages: 85-91

    Objectives: This study aimed to assess and compare the perception of laypersons and dental professionals of smile esthetics based on two factors namely gingival display and alignment of teeth.

    Materials and Methods: A total of 32 females were randomly selected among dental students in the International Campus of School of Dentistry, Tehran University of Medical Sciences (Tehran, Iran) with no previous history of esthetic dental work. Frontal photographs were obtained and cropped from the subnasal to menton areas of subjects to standardize the size of pictures. Three series of slides were prepared of the pictures using Microsoft PowerPoint software. The first series of slides were shown to familiarize the observers with the images. The second and third series were displayed for the observers and they were then asked to fill out a questionnaire. The group of observers included 10 dental specialists and 10 laypersons. Each observer was given a visual analog scale (VAS) chart for scoring (1-10). After completion of the questionnaires, data were transferred to a computer and the differences in judgments of professionals and laypeople were analyzed using the Mann Whitney test.

    Results: No significant difference was found in the judgments of professionals and laypeople on evaluating overall smile esthetics, gingival display and alignment of teeth except for the slide showing a reverse smile arc.

    Conclusions: Laypeople and professionals had similar perceptions of smile esthetics. Thus, it appears that clinicians can rely on the judgment of laypersons in esthetic dental treatments.

    Keywords: Smiling; Perception; Esthetics, Dental

  • XML | PDF | downloads: 242 | views: 291 | pages: 92-100

    Objectives: Composite restorations must have tooth-like optical properties namely color and translucency and maintain them for a long time. This study aimed to compare the effect of accelerated artificial aging (AAA) on the translucency of three methacrylate-based composites (Filtek Z250, Filtek Z250XT and Filtek Z350XT) and one silorane-based composite resin (Filtek P90).

    Materials and Methods: For this in vitro study, 56 composite discs were fabricated (n=14 for each group). Using scanning spectrophotometer, CIE L*a*b* parameters and translucency of each specimen were measured at 24 hours and after AAA for 384 hours. Data were analyzed using one-way ANOVA, Tukey’s test and paired t-test at P=0.05 level of significance.

    Results: The mean (±standard deviation) translucency parameter for Filtek Z250, Filtek Z250XT, Filtek Z350XT and Filtek P90 was 5.67±0.64, 4.59±0.77, 7.87±0.82 and 4.21±0.71 before AAA and 4.25±0.615, 3.53±0.73, 5.94±0.57 and 4.12±0.54 after AAA, respectively. After aging, the translucency of methacrylate-based composites decreased significantly (P<0.05). However, the translucency of Filtek P90 did not change significantly (P>0.05).

    Conclusions: The AAA significantly decreased the translucency of methacrylate-based composites (Filtek Z250, Filtek Z250XT and Filtek Z350XT) but no change occurred in the translucency of Filtek P90 silorane-based composite.

    Keywords: Composite Resins; Silorane Resins; Methacrylates

  • XML | PDF | downloads: 266 | views: 376 | pages: 101-107

    Objectives: Midazolam with variable dosages has been used to induce sedation in pediatric dentistry. The aim of this study was to compare the efficacy of two dosages of oral midazolam for conscious sedation of children undergoing dental treatment.

    Materials and Methods: In this randomized crossover double blind clinical trial, 20 healthy children (ASA I) aged three to six years with negative or definitely negative Frankl behavioral rating scale were evaluated. Half of the children received 0.5mg/kg oral midazolam plus 1mg/kg hydroxyzine (A) orally in the first session and 0.3mg/kg oral midazolam plus 1mg/kg hydroxyzine (B) in the next session. The other half received the drugs on a reverse order. Sedation degree by Houpt sedation rating scale, heart rate and level of SpO2 were assessed at the beginning and after 15 and 30 minutes. The data were analyzed using SPSS 19 and Wilcoxon Signed Rank and McNemar’s tests.

    Results: The results showed that although administration of 0.5mg/kg oral midazolam was slightly superior to 0.3mg/kg oral midazolam in terms of sedation efficacy, the differences were not significant (P>0.05). The difference in treatment success was not significant either (P>0.05). Heart rate, oxygen saturation (SpO2) and respiratory rate were within the normal range and did not show a significant change (P>0.05).

    Conclusions: The overall success rate of the two drug combinations namely 0.5mg/kg oral midazolam plus hydroxyzine and 0.3mg/kg oral midazolam plus hydroxyzine was not significantly different for management of pediatric patients.

    Keywords: Conscious Sedation; Pediatric Dentistry; Midazolam; Hydroxyzine

  • XML | PDF | downloads: 332 | views: 330 | pages: 108-115

    Objectives: Bone quality and quantity assessment is one of the most important steps in implant treatment planning. Different methods such as computed tomography (CT) and recently suggested cone beam computed tomography (CBCT) with lower radiation dose and less time and cost are used for bone density assessment. This in vitro study aimed to compare the tissue density values in Hounsfield units (HUs) in CBCT and CT scans of different tissue phantoms with two different thicknesses, two different image acquisition settings and in three locations in the phantoms.

    Materials and Methods: Four different tissue phantoms namely hard tissue, soft tissue, air and water were scanned by three different CBCT and a CT system in two thicknesses (full and half) and two image acquisition settings (high and low kVp and mA). The images were analyzed at three sites (middle, periphery and intermediate) using eFilm software. The difference in density values was analyzed by ANOVA and correction coefficient test (P<0.05).

    Results: There was a significant difference between density values in CBCT and CT scans in most situations, and CBCT values were not similar to CT values in any of the phantoms in different thicknesses and acquisition parameters or the three different sites. The correction coefficients confirmed the results.

    Conclusions: CBCT is not reliable for tissue density assessment. The results were not affected by changes in thickness, acquisition parameters or locations.

    Keywords: Bone Density; Cone-Beam Computed Tomography; Tomography, X-Ray Computed

  • XML | PDF | downloads: 301 | views: 312 | pages: 116-125

    Objectives: This study aimed to evaluate the effects of chlorhexidine mouthrinses on color stability of nanofilled and micro-hybrid resin-based composites.

    Materials and Methods: In this in-vitro study, 160 disc-shaped specimens (7x2mm) were fabricated of Filtek Z250 and Filtek Z350XT Enamel (A2 shade). The samples of each group were randomly divided into eight subgroups (n=10). The specimens were incubated in artificial saliva at 37˚C for 24 hours. The baseline color values (L*, a*, b*) of each specimen were measured according to CIE LAB system using a reflection spectrophotometer. After baseline color measurements, the control samples were immersed in saliva and the test groups were immersed in Kin (Cosmodent), Vi-One (Rozhin), Epimax (Emad), Hexodine (Donyaye Behdasht), Chlorhexidine (Shahrdaru), Najo (Najo) and Behsa (Behsa) mouthrinses once a day for two minutes. The specimens were then immersed again in saliva. This process was repeated for two weeks. Color measurements were made on days seven and 14. Two-way and one-way ANOVA and Tukey’s post hoc test, t-test and paired t-test were used to analyze data at a significance level of 0.05.

    Results: All specimens displayed color change after immersion in the mouthrinses. Significant interactions were found between the effects of materials and mouthrinses on color change.

    Conclusions: All composite resins tested showed acceptable color change after immersion in different mouthrinses. Filtek Z350XT showed less color change than Filtek Z250. Mouthrinses containing alcohol (Behsa and Najo) and citric acid (Vi-One) caused greater discoloration of composites.

    Keywords: Chlorhexidine; Color; Composite Resins; Mouthwashes

  • XML | PDF | downloads: 378 | views: 2864 | pages: 126-132

    Objectives: This study aimed to evaluate the location and characteristics of mental foramen, anterior loop and mandibular incisive canal using cone beam computed tomography (CBCT).

    Materials and Methods: This retrospective cross-sectional study evaluated 200 mandibular CBCT scans for the location of mental foramen, anterior loop prevalence and mandibular incisive canal visibility, its mean length and distance to buccal and lingual plates and inferior border of the mandible. The effect of age and gender on these variables was also analyzed (P<0.05).

    Results: Anterior loop and mandibular incisive canal were seen in 59.5% and 97.5% of the cases, respectively. The mean length of the mandibular incisive canal was 10.48±4.53mm in the right and 10.40±4.52mm in the left side. The mean distance from the endpoints of the canal to buccal plate was 3.63±1.73mm in the right and 3.66±1.45mm in the left side. These distances were 3.89±1.53mm in the right and 4.13±1.48mm in the left side to lingual plate and 9.98±2.07mm in the right and 8.62±1.97mm in the left side to the inferior border of the mandible. The distance from the endpoints of the canal to lingual plate was significantly different in the right and left sides. The distance from the endpoint of the canal to the buccal plate and inferior border of the mandible was significantly shorter in females (P=0.016), and had a weak, significant correlation with age (rsp=0.215, P=0.003).

    Conclusions: Due to variability in mandibular incisive canal length and high prevalence of anterior loop, CBCT is recommended before surgical manipulation of interforaminal region.

    Keywords: Anatomic Landmarks; Cone-Beam Computed Tomography; Mandible; Mandibular Nerve

Case Report

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    Dentinogenesis imperfecta (DI) is a hereditary dentin defect caused by an autosomal dominant mutation in dentin sialophosphoprotein gene. Defective dentin development results in discolored teeth that are prone to wear and fracture. Early diagnosis and proper treatment are necessary to achieve better functional and esthetic results and minimize nutritional deficiencies and psychosocial distress. In order to prevent excessive loss of tooth structure, placement of stainless steel crowns (SSCs) on deciduous and young permanent posterior teeth is recommended as soon as such teeth erupt. This clinical report presents the clinical manifestations and management of a 3.5-year-old child diagnosed with DI type II.

    Keywords: Dentin; Dentinogenesis Imperfecta; Tooth, Deciduous

  • XML | PDF | downloads: 208 | views: 322 | pages: 139-142

    Median cleft is the midline cleft of the lip. It develops due to incomplete or failed fusion of the median nasal prominence. It can present with minimal deformities such as involvement of the vermilion border, or complex clefting of the midline structures and brain. Median clefts are broadly classified as true and false clefts. This case report describes a rare case of median cleft of the upper lip involving the white roll, which was not associated with any other deformities. Treatment included reconstruction of the philtrum and the cupid’s bow while maintaining vermilion fullness and continuity, and minimizing scar formation. Various techniques have been advocated for treatment of this type of median upper lip cleft. Here we describe a technique using Pfeifer incision to correct our patient’s defect. Pfeifer incision consists of wavy lines and its use has been advocated for correction of various craniofacial abnormalities.

    Keywords: Median Cleft Lip; Hypertelorism; Craniofacial Abnormalities