Faruk Izzet Ucar

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.

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.

Orofacial airway dimensions in subjects with Class I malocclusion and different growth patterns

OBJECTIVE To test the null hypotheses that there are no significant differences in craniofacial structures and orofacial airway dimensions in subjects with Class I malocclusion and different growth patterns. MATERIALS AND METHODS Lateral cephalometric radiographs of 31 low angle (mean age, 14.0 ± 2.0 years; range, 10.3-16.5 years), 40 high angle (mean age, 12.7 ± 1.6 years; range, 10.1-16.2 years), and 33 normal growth (mean age, 13.9 ± 1.3 years; range, 11.2-16.8 years) subjects with Class I malocclusion were examined. In total, 34 measurements (27 craniofacial and 7 orofacial airways) were evaluated. Groups were constituted according to the SN-MP angle. Group differences were analyzed with analysis of variance (ANOVA) and the Tukey test, at the P < .05 level. RESULTS According to ANOVA, only 5 of the 27 craniofacial measurements showed no statistically significant differences among different growth patterns. For orofacial airway measurements, statistically significant differences were found in nasopharyngeal airway space (P < .01), palatal tongue space (P < .05), upper posterior airway space (PAS) (P < .05), and tongue gap (P < .001). No statistically significant orofacial airway differences were determined between low angle and normal growth subjects. High angle subjects had a larger tongue gap than those with normal and low angles (P < .01). Additionally, nasopharyngeal airway space (P < .01) and upper PAS (P < .05) measurements were larger and palatal tongue space (P < .05) was narrower in low angle than in high angle subjects. CONCLUSIONS The null hypotheses were rejected. Significant differences in craniofacial morphology and orofacial airway dimensions of Class I subjects with different growth patterns were identified.

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.

Condylar and ramal vertical asymmetry in adolescent patients with cleft lip and palate evaluated with cone-beam computed tomography.

INTRODUCTION The aims of this study were to evaluate condylar and ramal mandibular vertical asymmetry in a patient group affected by unilateral (UCLP) and bilateral (BCLP) cleft lip and palate, and to compare the findings with a well-matched control group with normal occlusion. METHODS The study groups included 20 UCLP patients (12 male, 8 female), 21 BCLP patients (12 male, 9 female), and a control group of 21 subjects with normal occlusion (10 male, 11 female). Measurements of condylar, ramal, and condylar plus ramal heights and asymmetry indexes were examined on cone-beam computed tomography images. One-way analysis of variance was used to determine potential statistical differences among the groups for condylar, ramal, and condylar plus ramal asymmetry index measurements. The post-hoc Tukey HSD test was used to determine individual differences. RESULTS No investigated group showed a statistically significant sex difference for any asymmetry index (P >0.05). There was a statistically significant difference between the normal and cleft sides in the ramal height and ramal plus condylar height measurements in the UCLP group (P = 0.004 and P = 0.006, respectively). The Tukey HSD test showed a statistically significant difference between the UCLP and BCLP groups in terms of ramal asymmetry index values (P = 0.018). CONCLUSIONS The ramal height and ramal plus condylar height measurements were significantly lower in the cleft side in the UCLP patients, and there was a statistically significant difference in ramal asymmetry index values between the patients affected by UCLP and BCLP.

Assessment of pharyngeal airway volume in adolescent patients affected by bilateral cleft lip and palate using cone beam computed tomography

OBJECTIVE To test the null hypothesis that there were no significant differences for pharyngeal airway volumes between the adolescent patients affected by bilateral cleft lip and palate (BCLP) and well-matched controls using cone beam computed tomography. MATERIALS AND METHODS The study sample consisted of 16 patients (11 female and 5 male; mean [SD] age 14.1 [2.1] years) affected by BCLP and 16 patients (10 female and 6 male; mean [SD] age 13.4 [2.0] years) as age- and sex-matched control group. Craniofacial measurements and pharyngeal airway dimension, area, and volume measurements of patients in both groups were calculated and statistically examined using Students t-test and multiple linear regression analyses. RESULTS Statistically significant differences were found between the BCLP and control groups for SNB (P < .05), SN-GoGn (P < .05), Co-A (P < .05), PAS (P < .01), minAx (P < .01), and oropharyngeal airway volume (P < .05). The most predictive variables for oropharyngeal airway volume were found as PAS (r  =  .655 and P  =  .000) and minAx (r  =  .787 and P  =  .000). CONCLUSIONS The null hypothesis was rejected. Oropharyngeal (P < .05) and total (P > .05) airway volumes were found to be less in the BCLP group, and thus the treatment choice in these patients should have positive effects on the pharyngeal airway.

Alveolar bone thickness and lower incisor position in skeletal Class I and Class II malocclusions assessed with cone-beam computed tomography

Objective To evaluate lower incisor position and bony support between patients with Class II average- and high-angle malocclusions and compare with the patients presenting Class I malocclusions. Methods CBCT records of 79 patients were divided into 2 groups according to sagittal jaw relationships: Class I and II. Each group was further divided into average- and high-angle subgroups. Six angular and 6 linear measurements were performed. Independent samples t-test, Kruskal-Wallis, and Dunn post-hoc tests were performed for statistical comparisons. Results Labial alveolar bone thickness was significantly higher in Class I group compared to Class II group (p = 0.003). Lingual alveolar bone angle (p = 0.004), lower incisor protrusion (p = 0.007) and proclination (p = 0.046) were greatest in Class II average-angle patients. Spongious bone was thinner (p = 0.016) and root apex was closer to the labial cortex in high-angle subgroups when compared to the Class II average-angle subgroup (p = 0.004). Conclusions Mandibular anterior bony support and lower incisor position were different between average- and high-angle Class II patients. Clinicians should be aware that the range of lower incisor movement in high-angle Class II patients is limited compared to average- angle Class II patients.

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.

Comparision of orofacial airway dimensions in subject with different breathing pattern.

OBJECTIVE To test the null hypothesis that there is no significant difference in the craniofacial morphology and orofacial airway dimensions between mouth breathing (MB) and nasal breathing (NB) subjects. MATERIALS AND METHODS Lateral cephalometric radiographs of 34 MB subjects (mean age: 12.8±1.5 years; range: 12.0-15.2 years) and 33 NB subjects (mean 13.9±1.3 years; age range: 12.2-15.8 years) with Class I occlusion were examined. Totally, 34 measurements (27 craniofacial and 7 orofacial airway) were evaluated. Group differences were statistically evaluated by independent samples t-test at p<0.05 levels. RESULTS Statistical comparisons showed that SNA (p<0.01), ANB (p<0.01), A to N perp (p<0.05), convexity (p<0.05), IMPA (p<0.05) and overbite (p<0.05) measurements were significantly lower in MB group when compared to NB group. However, SN-MP (p<0.01) and PP-GoGn (p<0.01) from angular measurements and S-N (p<0.05) and anterior facial height (p<0.05) from linear measurements were significantly higher in MB subjects. Among orofacial airway measurements, only upper posterior airway space was found significantly higher(p<0.001) in MB than NB subjects. CONCLUSIONS The null hypothesis was rejected. Mouth breathing affects craniofacial morphology and orofacial airway dimensions.