Tancan Uysal

Condylar and ramal vertical asymmetry in unilateral and bilateral posterior crossbite patients and a normal occlusion sample

INTRODUCTIONnOur objective was to evaluate the condylar, ramal, and condylar-plus-ramal mandibular vertical asymmetry in a group of adolescent subjects with normal occlusion and unilateral and bilateral posterior crossbite malocclusions.nnnMETHODSnMandibular asymmetry index measurements (condylar, ramal, and condylar-plus-ramal) were made on the panoramic radiographs of 126 subjects (51 boys, 75 girls). The study groups consisted of 46 unilateral (19 boys, 27 girls; mean age, 13.06 +/- 3.52 years) and 40 bilateral (16 boys, 24 girls; mean age, 12.72 +/- 3.22 years) posterior crossbite patients and a group of 40 subjects (16 boys, 24 girls; mean age, 14.43 +/- 3.05 years) with normal occlusion. One-way analysis of variance (ANOVA) was used to determine possible statistically significant differences between the groups for condylar, ramal, and condylar-plus-ramal asymmetry index measurements at the 95% confidence interval.nnnRESULTSnNo group showed statistically significant sex- or side-specific differences for posterior vertical height measurements (P > 0.05). Asymmetry indexes (condylar, ramal, and condylar-plus-ramal) were similar, and no statistically significant differences were found among the unilateral and bilateral posterior crossbite groups and the normal occlusion sample.nnnCONCLUSIONSnNo statistically significant sex- or side-specific mandibular asymmetry was found among the 3 groups. Condylar asymmetry index values were significantly high compared with the 3% threshold value in each of the 3 groups, but comparisons between groups were not statistically significant.

Angular photogrammetric analysis of the soft tissue facial profile of Turkish adults

One of the most important components of orthodontic diagnosis and treatment planning is the evaluation of the patients soft tissue profile. The aim of this study was to develop angular photogrammetric standards for Class I Anatolian Turkish males and females. A random sample of 100 Turkish individuals (46 males and 54 females; ages 19-25 years) was obtained. The photographic set-up consisted of a tripod that held a 35 mm camera and a primary flash. The camera was used in its manual position and photographic records were taken of the subjects in natural head posture. The photographic records, 35 mm slide format, were digitized and analyzed using the Quick Ceph Image software program for Windows. Twelve measurements were digitally analyzed on each photograph. For statistical evaluation a Students t-test was performed and the reliability of the method was analyzed. The results were compared with reported norms of facial aesthetics. The nasofrontal (G-N-Prn), nasal (Cm-Sn/N-Prn), vertical nasal (N-Prn/TV), and nasal dorsum (N-Mn-Prn) angles showed statistically insignificant gender differences (P>0.05). The nasolabial angle (Cm-Sn-Ls) demonstrated large variability. Gender differences were present in the mentolabial (Li-Sm-Pg) and cervicomental (G-Pg/C-Me) angles. The mentolabial angle showed a high method error and large variability. Facial (G-Sn-Pg) and total facial (G-Prn-Pg) convexity angles were similar, while Cm-Sn-Ls angle range was larger compared with other angles. The mean values obtained from this sample can be used for comparison with records of subjects with the same characteristics and following the same photogrammetric technique. Angular photogrammetric profile analysis can provide the orthodontist with a way of determining problems associated with various soft tissue segments of the face.

Evaluation of speed, repeatability, and reproducibility of digital radiography with manual versus computer-assisted cephalometric analyses

The aims of this study were to evaluate intra-examiner repeatability and inter-examiner reproducibility of landmarks using two cephalometric analysing techniques, manual and computerized, and to compare these for speed. One hundred lateral cephalometric radiographs were randomly selected and 11 angular and six linear parameters were traced and measured by two examiners using the manual method and Dolphin Image Software 9.0 on each radiograph. A Students t-test for paired and independent samples was used to compare the mean values of intra- and inter-examiner differences. Intraclass correlation coefficients (ICC) were calculated to determine intra- and inter-examiner correlation (r value). Both operators were generally consistent in the repeated measurements; however, for one examiner, the differences for Na is perpendicular to A (P < 0.001), Na is perpendicular Pog, and U1-NA (P < 0.01) distance measurements were found to be statistically significant. Intra-examiner repeatability of landmarks both with the manual and Dolphin techniques showed high correlation coefficients. While inter-examiner reproducibility of landmarks was unacceptable, measurement errors with the manual technique were generally comparable with the Dolphin technique. The mean tracing times of the two operators for a single tracing was 2 minutes 41 seconds for Dolphin and 6 minutes 51 seconds for manual tracings. Computer-assisted cephalometric analysis does not increase intra- and inter-examiner reliability but can result in time saving.

New regression equations for mixed-dentition arch analysis in a Turkish sample with no Bolton tooth-size discrepancy

INTRODUCTIONnOur objectives were to establish new regression equations derived from 228 Turkish patients (100 boys, 128 girls) with no intermaxillary tooth-size discrepancy that would give the greatest correlation coefficient for the sum of permanent tooth widths of the canines and the premolars of both jaws, according to sex, and to compare our new data with those from other studies.nnnMETHODSnMesiodistal tooth widths were measured from dental casts. Student t tests were carried out to compare tooth sizes between the sexes and the right and left sides of the arches. The constants a and b in the standard linear regression equation (y = a + bx), the correlation coefficients (r), the coefficients of determination (r2), and the standard errors of the estimates (SEE) were calculated.nnnRESULTSnStatistically significant differences were found between the widths of teeth between the sexes in both the maxillary (P <0.01) and mandibular (P <0.001) arches. The r value was 0.956 to 0.989, with the higher coefficients in the girls. The r2 values were 91% in boys and 98% in girls, and the SEE was better in the maxilla and the mandible (0.013 mm) for the girls. The regression equations produced predictions of mesiodistal width summations for the maxillary and mandibular canine and premolar segments that were much different from other reported studies.nnnCONCLUSIONSnNew regression equations were derived for Turkish people. The prediction equations and probability tables should be revised by using subjects with no tooth-size discrepancy.

Can intracoronally bleached teeth be bonded safely

INTRODUCTIONnOur objective was to determine the effects of intracoronal bleaching on the shear bond strength and failure side location of metallic brackets at 2 times (bleaching immediately before bonding and 30 days before bonding).nnnMETHODSnSixty freshly extracted mandibular incisors were randomly divided into 3 groups; each group contained 20 teeth. After finishing canal preparation and root canal filling, the root fillings were removed to a level 2 mm apical to the cementoenamel junction. Glass ionomer base (Vitrabond, 3 M Dental Products, St Paul, Minn) was placed approximately 2-mm thick. Bleaching agent (Whiteness Perfect, FGM Dental Products, Joinville, Brazil) was placed into the rest of the cavity for 4 days at 2 times. Shear bond strength of these brackets was measured in megapascals. The adhesive remnant index (ARI) scores were determined after the brackets failed. Data were analyzed with analysis of variance (ANOVA), Tukey, and chi-square tests.nnnRESULTSnThe bond strengths of the group with no bleaching (mean, 20.25 +/- 7.06 MPa) were significantly higher (P >0.001) than those of the group that had bleaching immediately before bonding (mean, 4.85 +/- 3.22 MPa) and the group that had bleaching 30 days before bonding (mean, 8.70 +/- 4.93 MPa). The results of the chi-square comparisons indicated significant differences among the 3 groups. In the group with no bleaching, there was a higher frequency of ARI scores of 2 to 4, indicating cohesive failures in the resin. In the other 2 groups, the failures were mostly adhesive at the resin-enamel interface (ARI scores of 4 and 5).nnnCONCLUSIONSnIntracoronal bleaching with carbamide peroxide adversely affected the shear bond strength and changed the site of failure during debonding when bonding was done immediately or 30 days after bleaching.

Evaluation of shear bond strength of metallic and ceramic brackets bonded to enamel prepared with self-etching primer

The aim of this in vitro study was to evaluate the shear bond strength (SBS) of different metallic and ceramic bracket bonding combinations using self-etching primers (SEPs). Eighty freshly extracted human premolar teeth were randomly divided into four equal groups for bonding with ceramic or metallic brackets as follows: group 1, metallic brackets bonded with conventional acid etching; group 2, metallic brackets bonded with Transbond Plus Self-Etching primer (TPSEP); group 3, ceramic brackets bonded as per group 1; group 4, ceramic brackets bonded as per group 2. The SBS of these brackets was measured and recorded in megapascals (MPa). The adhesive remnant index (ARI) scores were determined after bracket failure. Data were analyzed with the analysis of variance, Tukey, and chi-square tests. The bond strength of group 3 (mean: 36.7 +/- 11.8 MPa) was significantly higher than group 4 (mean: 26.6 +/- 8.9 MPa; P < 0.05), group 1 (mean: 25.5 +/- 5.1 MPa; P < 0.01), and group 2 (mean: 22.9 +/- 7.3 MPa; P < 0.001). No significant differences in debond locations were found among the groups (P > 0.05). Compared with conventional acid etching, SEPs significantly decreased the SBS of ceramic orthodontic brackets.

Microleakage of orthodontic band cement at the cement-enamel and cement-band interfaces

INTRODUCTIONnOur objective was to determine and compare microleakage patterns of conventional glass ionomer cement (GIC), resin modified GIC (RMGIC), and polyacid-modified composite for band cementation.nnnMETHODSnSixty freshly extracted third molars were randomly divided into 3 groups of 20 teeth each. Microetched molar bands in the 3 groups were cemented to enamel with one of three orthodontic cements: Ketac-Cem (3M ESPE, Gmbh, Seefeld, Germany), Multi-Cure (3M Unitek, Monrovia, Calif), and Transbond Plus (3M Unitek). A dye penetration method was used for microleakage evaluation. Microleakage was determined by a stereomicroscope for the cement-band and cement-enamel interfaces from both the buccal and lingual margins. Statistical analysis was performed with Kruskal-Wallis and Mann-Whitney U tests.nnnRESULTSnThe buccal sides had similar microleakage values compared with the lingual sides for the cement-enamel and cement-band interfaces with all cements. Statistical comparisons showed statistically significant differences among the band cements between both interfaces (P <0.001). When the cement systems were compared, conventional GIC showed the highest leakage scores between cement-band (median, 3.50 mm) and cement-enamel (median, 2.88 mm) interfaces. Teeth banded with RMGIC and modified composite showed similar microleakage scores, and both had less leakage (<1 mm) than conventional GIC.nnnCONCLUSIONSnConventional GIC is associated with more microleakage than RMGIC and modified composite at both the cement-band and cement-enamel interfaces.

Bond strengths of an antibacterial monomer-containing adhesive system applied with and without acid etching for lingual retainer bonding

The aim of this study was to test the null hypothesis that there is no significant difference in bond strength and failure site location of composite bonded to etched and unetched enamel with an antibacterial monomer-containing adhesive and a conventional lingual retainer adhesive system. The crowns of 60 extracted lower human incisors were mounted in acrylic resin leaving the lingual surface of the crowns parallel to the base of the moulds. The teeth were randomly divided into three equal groups: two experimental and a control. Conventional lingual retainer composite (Transbond LR) and antibacterial monomer-containing adhesive (Clearfil Protect Bond), with or without prior etching, were applied to the lingual surface of the teeth by packing the material into cylindrical plastic matrices (Ultradent) with an internal diameter of 2.34 mm and a height of 3 mm to simulate lingual retainer bonding. The shear bond data were analysed using analysis of variance and Tukeys tests. Fracture modes were analysed by chi-square test. Statistical analysis showed that the bond strengths of the control (Transbond LR, mean: 24.77 +/- 9.25 MPa) and Clearfil Protect Bond with etching, (mean: 20.24 +/- 8.5 MPa) were significantly higher than Clearfil Protect Bond without etching, (mean: 12.56 +/- 6.93 MPa). In general, a greater percentage of the fractures were adhesive, at the tooth-composite interface (60-65 per cent). No statistically significant difference was found among the groups. The hypothesis is thus rejected. Within the limits of this in vitro model, antibacterial monomer-containing self-etch adhesive with acid etching did not significantly affect shear bond strength when compared with the control. However, the same adhesive used without acid etching resulted in a significant decrease in bond strength.

Cone-beam computed tomography evaluation of relationship between tongue volume and lower incisor irregularity

The aim of this study was to evaluate the relationship between the tongue volume and lower incisor irregularity, using cone-beam computed tomography (CBCT), and to identify the possible gender differences. CBCT images of 60 patients between 16 and 36 years of age were selected from 1400 sets of images in the database. Tomography was carried out using iCAT® (Imaging Sciences International, Hatfield, Pennsylvania, USA) and segmentation was carried out by using Mimics 10.1 software (Materialise NV, Leuven, Belgium). The tongue volume was calculated by using the volume of the voxels from the scan and the number of voxels selected for a given mask. Lower incisor crowding was measured with the Littles irregularity index and divided into three groups: mild, moderate, and severe. Independent samples t-test, analysis of variance (ANOVA), and Tukey test were used at P < 0.05 level. Pearson correlation coefficients and linear regression model were calculated to determine the correlation between tongue volume and incisor irregularity. No significant gender dimorphism was found for the tongue volume (females: 28.13 ± 8.54 cm(3) and males: 31.02 ± 9.75 cm(3)). According to ANOVA, there was statistically significant difference in the tongue volume measurements among subjects with different levels of irregularity. Tukey analysis indicated that mild irregularity group (33.97 cm(3)) showed higher values for tongue volume than severe irregularity group (26.60 cm(3); P = 0.025). The relationship between incisor irregularity and tongue volume was evaluated for both genders and significant inverse correlation (r = -0.429; P = 0.029) was determined between lower incisor irregularity and tongue volume in males. In female group, no significant correlation was determined between tongue volume and incisor irregularity.

EMG PSD Measures in Orthodontic Appliances

The human body consists of different systems which include the nervous system, the cardiovascular system, the musculoskeletal system, etc. Each system performs some kind of vital task and carries on many physiological processes. For example, the primary functions of the musculoskeletal system can be summarized as generating forces, producing motion, moving substance within the body, providing stabilization, and generating heat. Physiological processes are multifaceted fact and most of them manifest themselves as signals that reflect their nature and activities. These types of signals may be hormonal, physical or electrical. The general name of the electrical signals taken from the related organ or physiologic process with invasive or non-invasive methods is called Biomedical Signals. This signal is normally a function of time and is definable in terms of its amplitude, frequency and phase (Rangayyan, 2002). The electromyography (EMG) signal is a biomedical signal that detects the electrical potential generated by muscle cells when these cells contract, and also when the cells are at rest. Three types of muscle tissue can be identified. One of them is the skeletal muscle, and the others are the smooth muscle and the cardiac muscle. The EMG is applied to the study of skeletal muscle (Reaz et al., 2006). Skeletal muscles are comprised by nearly parallel cells and the muscle fibers which constitute the contractile structural units. Muscle fibers are activated by the central nervous system through electrical signals transmitted by motoneurons. A single motoneuron together with the muscle fibers that it contacts is called a motor unit which is the smallest functional subdivision of the neuromuscular system (Moritani, et al. 2004) The central nervous system controls the activation of motor units to optimize the interaction between our body and the surrounding environment. When the motor units are activated by the central nervous system, they produce an action potential trains of the active motor units add together to generate the interference EMG signal. Surface and needle electrodes have been used to detect EMG of muscles. Surface electrodes have been widely used to investigate neuromuscular functions because of their several advantages, for example, it is noninvasive, easy to adhere to the skin and to detect the total activities of the muscle and it was called Surface EMG (SEMG). Bu the real advantage of this technique is that it is more beneficial in studies, in which simultaneous movement of many muscles is examined in vast muscle groups. On the other hand, surface electrodes have disadvantages as well. Due to the broad area for receiving signals on respective muscle