Törün Özer

Etching Enamel for Orthodontics with an Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet Laser System

OBJECTIVE To test the shear bond strength, surface characteristics, and fracture mode of brackets that are bonded to enamel etched with an erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser operated at different power outputs: 0.5 W, 1 W, and 2 W. MATERIALS AND METHODS Human premolars that had been extracted for orthodontic purposes were used. Enamel was etched with an Er,Cr:YSGG laser system operated at one of three power outputs or with orthophosphoric acid. RESULTS The shear bond strength associated with the 0.5-W laser irradiation was significantly less than the strengths obtained with the other irradiations. Both the 1-W and 2-W laser irradiations were capable of etching enamel in the same manner. This finding was confirmed by scanning electron microscopy examination. The evaluation of adhesive-remnant-index scores demonstrated no statistically significant difference in bond failure site among the groups, except for the 0.5-W laser-etched group. Generally, more adhesive was left on the enamel surface with laser irradiation than with acid etching. CONCLUSION The mean shear bond strength and enamel surface etching obtained with an Er,Cr: YSGG laser (operated at 1 W or 2 W for 15 seconds) is comparable to that obtained with acid etching.

Laser etching of enamel for orthodontic bonding

INTRODUCTION The purposes of this study were to assess the shear bond strength, the surface characteristics, and the adhesive remnant index scores of teeth prepared for bonding with erbium, chromium doped: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser etching, and to compare laser etching with phosphoric-acid etching and a self-etching primer. METHODS Sixty-four premolars, extracted for orthodontic purposes, were randomly divided into 4 groups, and a different method was used to prepare the tooth enamel in each group for bonding: irradiation for 15 seconds with a 0.75-W Er,Cr:YSGG laser; irradiation for 15 seconds with a 1.5-W Er,Cr:YSGG laser; etching with 37% phosphoric acid; application of a self-etching primer. After surface preparation, standard edgewise stainless steel premolar brackets were bonded; 1 tooth in each group was not bonded and was examined under a scanning electron microscopic. The brackets were debonded 24 hours later; shear bond strengths were measured, and adhesive remnant index scores were recorded. RESULTS Irradiation with the 0.75-W laser produced lower shear bond strengths than the other methods. No statistically significant differences were found between 1.5-W laser irradiation, phosphoric-acid etching, and self-etching primer. Adhesive remnant scores were compared with the chi-square test, and statistically significant differences were found between all groups; when the 0.75-W laser irradiation group was excluded, no statistically significant differences were observed. CONCLUSIONS Irradiation with a 1.50-W laser produced sufficient etching for orthodontic bonding, but irradiation with the 0.75-W laser did not.

Evaluation of root resorption following rapid maxillary expansion using cone-beam computed tomography.

OBJECTIVE To evaluate the root resorption after rapid maxillary expansion (RME) via cone-beam computed tomography (CBCT). MATERIALS AND METHODS Records of 25 patients who had undergone RME with tooth-borne banded expander were obtained from the archive of the orthodontic department. CBCT data were reconstructed with surface and volume rendering, and the volumetric images were manipulated to display the root surfaces from various orientations. On these three-dimensional images, permanent first molars and first and second premolars were segmented, and their roots were isolated. Volumes of roots were calculated. The difference between pre-expansion and postexpansion root volumes was statistically evaluated with a paired-samples t-test. Also, the percentage of root volume loss was calculated for each root and statistically compared with each other with one-way analysis of variance at the P < .05 level. RESULTS The difference between the pre-expansion and postexpansion root volumes was statistically significant for all roots investigated. Maximum volume decrease was observed for the mesiobuccal root of first molar teeth (18.60 mm(3)). It was determined that the distobuccal root of first molar teeth was less affected from the expansion procedure (9.47 mm(3)). No statistically significant difference was found for the percentage of root volume loss. CONCLUSION Following RME treatment, significant root volume loss was observed for all investigated posterior teeth. However, the percentage of volume loss was not statistically different among roots.

Dehiscence and fenestration in skeletal Class I, II, and III malocclusions assessed with cone-beam computed tomography

OBJECTIVE To test the null hypothesis that the presence of dehiscence and fenestration was not different among patients with skeletal Class I, II, and III malocclusions. MATERIALS AND METHODS In this retrospective study, a total of 123 cone-beam computed tomography (CBCT) images were obtained with an iCAT scanner (Imaging Sciences International, Hatfield, Pa). Patients with normal vertical patterns were classified according to dental malocclusion and ANB angle. Class I comprised 41 patients-21 girls and 20 boys (mean age, 22.4 ± 4.5 years); Class II comprised 42 patients-22 girls and 20 boys (mean age, 21.5 ± 4.2 years); and Class III comprised 40 subjects-22 girls and 18 boys (mean age, 22.1 ± 4.5 years). A total of 3444 teeth were evaluated. Analysis of variance and Tukeys test were used for statistical comparisons at the P < .05 level. RESULTS Statistical analysis indicated that the Class II group had a greater prevalence of fenestration than the other groups (P < .001). No difference was found in the prevalence of dehiscence among the three groups. Although fenestration had greater prevalence in the maxilla, more dehiscence was found in the mandible for all groups. In Class I, alveolar defects (dehiscence, fenestration) were matched relatively in both jaws. Furthermore, Class II and Class III subjects had more alveolar defects (41.11% and 45.02%, respectively) in the mandible. Dehiscences were seen with greater frequency in the mandibular incisors of all groups. CONCLUSION The null hypothesis was rejected. Significant differences in the presence of fenestration were found among subjects with skeletal Class I, Class II, and Class III malocclusions. Fenestrations had greater prevalence in the maxilla, but more dehiscences were found in the mandible.

Comparison of sandblasting, laser irradiation, and conventional acid etching for orthodontic bonding of molar tubes

The purpose of the study was to determine if sandblasted and laser-irradiated enamel may be viable alternatives to acid etching for molar tube bonding. Seventy-seven molar teeth extracted for periodontal reasons were used. Seventy teeth underwent shear bond strength (SBS) testing and the remaining seven were examined under scanning electron microscopy (SEM). Adhesive remnant index (ARI) scores were also considered. An erbium, chromium-doped:yttrium-scandium-gallium-garnet (Er, Cr: YSGG) laser was used for enamel etching. Sandblasted and laser-irradiated enamel surfaces with different power outputs (0.5, 0.75, 1, 1.5, and 2 W) were compared with conventional phosphoric acid etching. Descriptive statistics, including mean, standard deviation, and minimum and maximum values, were calculated for each group. Multiple comparisons of the SBS of different etching types were performed by analysis of variance testing. The chi-square test was used to evaluate differences in ARI scores between groups. Acid-etched, 1-, 1.5-, and 2-W laser irradiation groups demonstrated a clinically acceptable mean SBS (7.65 +/- 1.38, 6.69 +/- 1.27, 7.13 +/- 1.67, 7.17 +/- 1.69 MPa, respectively). Irradiation with an output of 0.5 and 0.75 W and sandblasting of the enamel showed a lower SBS than the other groups (2.94 +/- 1.98, 4.16 +/- 2.87, 2.01 +/- 0.64 MPa, respectively). SEM evaluation of 1, 1.5, and 2 W laser irradiation revealed similar etching patterns to acid etching. Sandblasting and 0.5, and 0.75 W laser etching were not able to etch enamel in preferential patterns. Laser irradiation at 1.5 and 2 W was able to etch enamel. More adhesive was left on the enamel surface with low-power laser irradiation. Sandblasting and low-power laser irradiation (0.5, 0.75, and 1 W) are not capable of etching enamel suitable for orthodontic molar tube bonding, but 1.5- and 2-W laser irradiation may be an alternative to conventional acid etching.

Mandibular asymmetry in unilateral and bilateral posterior crossbite patients using cone-beam computed tomography.

OBJECTIVE To test the hypotheses that (1) there is no difference in mandibular asymmetry between the crossbite and normal side in a unilateral crossbite group (UCG) and between the right and left sides in a bilateral crossbite group (BCG) and a control group (CG); and (2) there is no significant difference in mandibular asymmetry among crossbite groups and control group. MATERIALS AND METHODS The cone-beam computed tomography scans of three groups were studied: (1) 15 patients (6 male, 9 female; mean age: 13.51 ± 2.03 years) with unilateral posterior crossbite; (2) 15 patients (8 male, 7 female; mean age: 13.36 ± 2.12 years) with bilateral posterior crossbite; and (3) 15 patients (8 male, 7 female; mean age: 13.46 ± 1.53 years) as a control group. Fourteen parameters (eight linear, three surface, and three volumetric) were measured. Side comparisons were analyzed with paired samples t-test, and for the intergroup comparison, analysis of variance (ANOVA) and Tukey tests were used at the P < .05 level. RESULTS According to side comparisons, no statistically significant difference was found in the UCG. There were statistically significant differences in hemimandibular (P = .008) and ramal (P = .004) volumes for the BCG and in ramal height (P = .024) and body length (P = .021) for the CG. Intergroup comparisons revealed significant differences in hemimandibular (P = .002) and body volume (P < .001) for the normal side of the UCG and left sides of the other groups, and in angular unit length (P = .025) and condylar width (P = .007) for the crossbite side of the UCG and the right sides of the other groups. CONCLUSIONS Contrary to UCG, CG and BCG were found to have side-specific asymmetry. Skeletal components of the mandible have significant asymmetry among the crossbite groups and the CG.

Surface roughness of the restored enamel after orthodontic treatment

INTRODUCTION After fixed appliance treatment, one concern is to restore the enamel surface as closely to its original state as possible. A variety of cleanup processes are available, but all are time-consuming and carry some risk of enamel damage. The purpose of this study was to examine tooth surfaces restored with different cleanup protocols. METHODS Ninety-nine premolars extracted for orthodontic purposes were used. The 2 materials tested were Sof-Lex disks (3 M ESPE AG, Seefeld, Germany) and fiberglass burs (Stain Buster, Carbotech, Ganges, France). These were used alone and in combination with high- and low-speed handpieces, with which they were also compared. Eight groups were ultimately tested. All groups were compared with intact enamel, which served as the control group. From each group, 10 samples were examined with profilometry and 1 with scanning electron microscopy. Adhesive remnant index scores were recorded to ensure equal distributions for the groups. The time required for the cleanup processes and profilometry test results were also recorded. RESULTS The fastest procedure was performed with high-speed handpieces, followed by low-speed handpieces. Sof-Lex disks and fiberglass burs required more time than carbide burs but did not result in significantly longer times for the cleanup procedure when combined with tungsten carbide-driven low- or high-speed handpieces or when used alone with low-speed handpieces. Although Sof-Lex disks were the most successful for restoring the enamel, it was not necessary to restore the enamel to its original surface condition. Generally, all enamel surface-roughness parameters were increased when compared with the values of intact enamel. The average roughness and maximum roughness depth measurements with Sof-Lex disks were statistically similar to measurements of intact enamel. CONCLUSIONS No cleanup procedure used in this study restored the enamel to its original roughness. The most successful was Sof-Lex disks, which restored the enamel closer to its original roughness.

Interleukine-1β and Tumor Necrosis Factor–α Levels in the Human Gingival Sulcus during Orthodontic Treatment

Abstract Objective: To test whether interleukine 1β (IL-1β) and tumor necrosis factor–α (TNF-α) levels differ from each other in different treatment levels. Materials and Methods: Eighteen patients, nine female and nine male (aged 16–19 years; mean 17.4 ± 1.8 years), participated in this study. Each subject underwent a session on professional oral hygiene and received oral hygiene instructions. Two months later, a fixed orthodontic appliance was placed. The patients were seen at baseline, at days 7 and 21 and at the 3rd and 6th month as the leveling of the teeth occurred. Records of the baseline scores for the distalization forces were taken at the 6th month. Days 7 and 21 after 6 months of treatment were also recorded. Results: There were increases in the volume of gingival crevicular fluid (GCF) and in the concentrations of IL-1β and TNF-α. Conclusions: Leveling and distalization of the teeth evoke increases in both the IL-1 and TNF-α levels that can be detected in GCF.

Dehiscence and fenestration in patients with different vertical growth patterns assessed with cone-beam computed tomography

OBJECTIVE To test the null hypothesis that the presence of alveolar defects (dehiscence and fenestration) was not different among patients with different vertical growth patterns. MATERIALS AND METHODS A total of 1872 teeth in 26 hyper-divergent (mean age: 24.4 ± 4.8 years), 27 hypo-divergent (mean age: 25.1 ± 4.5 years), and 25 normo-divergent (mean age: 23.6 ± 4.1 years) patients with no previous orthodontic treatment were evaluated using cone-beam computed tomography. Axial and cross-sectional views were evaluated with regard to whether dehiscence and/or fenestration on buccal and lingual surfaces existed or not. For statistical analysis, the Pearson chi-square test was used at a P < .05 significance level. RESULTS According to the statistical analysis, the hypo-divergent group (6.56%) had lower dehiscence prevalence than the hyper-divergent (8.35%) and normo-divergent (8.18%) groups (P  =  .004). Higher prevalences of dehiscence and fenestration were found on buccal sides in all vertical growth patterns. While fenestration was a common finding for the maxillary alveolar region, dehiscence was a common finding in the mandible in all groups. CONCLUSION The null hypothesis was rejected. Although the prevalence of fenestrations was not different, significant differences for dehiscences were found in patients with different vertical growth patterns.

Use of cone beam computed tomography in otolaryngologic treatments

Cone beam computed tomography (CBCT) allows us to evaluate 3-dimensional (3D) morphology of the maxillofacial skeleton and also used in dentomaxillofacial imaging to solve complex diagnostic and treatment planning problems such as craniofacial fractures, temporamandibular dysfunctions or sinus imaging. CBCT uses a rectangular or round 2D detector, which allows a single rotation of the gantry to generate a scan of the entire region of interest. Technological and application-specific factors such as development of compact, relatively low-cost, high-quality, large, flat-panel detector arrays; the availability of low-cost computers with processing power sufficient for cone beam image reconstruction; the fabrication of highly efficient radiograph tubes capable of multiple exposures necessary for cone beam scanning at prices lower than those currently used for fan beam CT; and limited volume scanning (e.g., head and neck) eliminating the need for subsecond gantry rotation speeds make this possible. The objective of this study is to review published evidence for CBCT having an important role in ORL treatments. We aimed to review all the available literature about the CBCT imagination in ORL treatments. Systematic literature search was performed using PubMed and Ovid. Additional literature was retrieved from reference lists in the articles. Systematic analysis of the literature from 1998 to 2010 was performed. A total of 40 abstracts were evaluated independently by two members of the project group, and 38 articles were included in the review.