ABSTRACT
The aim of this study was to evaluate differences in craniofacial morphology, head posture and hyoid bone position between mouth breathing [MB] and nasal breathing [NB] patients. Mouth breathing patients comprised 34 skeletal Class I subjects with a mean age of 12.8 +/- 1.5 years [range: 12.0-15.2 years]. Thirty-two subjects with skeletal Class I relationship were included in the NB group [mean 13.5 +/- 1.3 years; range: 12.2-14.8 years]. Twenty-seven measurements [15 angular and 12 linear] were used for the craniofacial analysis. Additionally, 12 measurements were evaluated for head posture [eight measurements] and hyoid bone position [four measurements]. Student's /-test was used for the statistical analysis. Probability values <0.05 were accepted as significant. Statistical comparisons showed that sagittal measurements including 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 found to be lower in MB patients compared to NB. Vertical measurements including SN-MP [p < 0.01] and PP-GoGn [p < 0.01], S-N [p <0.05] and anterior facial height [p < 0.05] were significantly higher in MB patients, while the odontoid proses and palatal plane angle [OPT-PP] was greater and true vertical line and palatal plane angle [Vert-PP] was smaller in MB patients compared to NB group [p < 0.05 for both]. No statistically significant differences were found regarding the hyoid bone position between both groups. The maxilla was more retrognathic in MB patients. Additionally, the palatal plane had a posterior rotation in MB patients. However, no significant differences were found in the hyoid bone position between MB and NB patients
ABSTRACT
OBJECTIVE: To study and compare the effects of different demineralization-inhibition methods on the shear bond strength (SBS) and fracture mode of an adhesive used to bond orthodontic brackets to demineralized enamel surfaces. METHODS: Eighty freshly extracted, human maxillary premolars were divided into 4 equal groups and demineralized over the course of 21 days. Brackets were bonded to the demineralized enamel of teeth in Group 1. In Group 2, bonding was performed following resin infiltration (ICON(R), DMG, Hamburg, Germany). Before bonding, pre-treatment with acidulated phosphate fluoride (APF) or solutions containing casein phosphopeptide-amorphous calcium phosphate with 2% neutral sodium fluoride (CPP-ACP/wF) was performed in Groups 3 and 4, respectively. The SBS values of the brackets were measured and recorded following mechanical shearing of the bracket from the tooth surface. The adhesive remnant index (ARI) scores were determined after the brackets failed. Statistical comparisons were performed using one-way ANOVA, Tukey's post-tests, and G-tests. RESULTS: Significant differences were found in some of the intergroup comparisons of the SBS values (F = 39.287, p < 0.001). No significant differences were found between the values for the APF-gel and control groups, whereas significantly higher SBS values were recorded for the resin-infiltrated and CPP-ACP/wF-treated groups. The ARI scores were also significantly different among the 4 groups (p < 0.001). CONCLUSIONS: Tooth surfaces exposed to resin infiltration and CPP-ACP/wF application showed higher debonding forces than the untreated, demineralized surfaces.