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Objective: To test the hypothesis that twin-block and Mandibular Protraction Appliance-IV (MPA-IV) are not effective in improving the pharyngeal airway passage (PAP) dimensions among Class II malocclusion subjects with a retrognathic mandible. Materials and Methods: Eighty-three subjects ranging in age from 8 to 14 years were divided into four groups. Group I included 30 Class I malocclusion subjects (healthy controls); group II consisted of 16 Class II malocclusion subjects (Class II controls); group III had 16 subjects in whom Class II malocclusion was treated by MPA-IV; and the remaining 21 subjects formed group IV, whose Class II malocclusions were corrected by twin-block appliance. Lateral cephalograms recorded at the beginning of orthodontic treatment in group I subjects and at the beginning and end of follow-up/treatment with functional appliance in group II, III, and IV subjects were analyzed to determine the PAP dimensions. Paired t-test, one-way analysis of variance, and Tukey tests were applied for statistical analysis, and a P-value .05 was considered statistically significant. Results: Soft palate length was decreased significantly in group III (P , .05) and group IV (P , .001) subjects. Soft palate thickness in group IV subjects was increased significantly as compared to group II (P , .05) and group III (P , .01) subjects. The improvement in soft palate inclination in group III and group IV subjects was significant (P , .01). The oropharynx depth was increased significantly in group III (P , .05) and group IV (P , .001) subjects. The depth of the hypopharynx was increased significantly (P , .01) in group IV subjects. Conclusions: The twin-block appliance was more efficient than the MPA-IV in the improvement of PAP dimensions among Class II malocclusion subjects with retrognathic mandible. (Angle Orthod. 2013;83:728-734.)

BackgroundThe use of functional appliances for the correction of retrognathic mandible is very common in orthodontics. Similar appliances known as oral appliances are also frequently used in adults for the treatment of mild to moderate obstructive sleep apnea (OSA). Many studies have reported improvement of pharyngeal airway passage (PAP) dimensions following functional appliance therapy in children and oral appliance therapy in adults. There is only one study in the literature that discussed the effect of oral appliance therapy on posterior pharyngeal wall thickness (PPWT) among subjects with OSA. The effect of functional appliance therapy on PPWT has never been investigated. Thus the present study was conducted to evaluate the effects of twin-block appliance on pharyngeal airway passage (PAP) dimensions and posterior pharyngeal wall thickness (PPWT) in class II malocclusion subjects with retrognathic mandibles.MethodsThirty-eight class II malocclusion subjects in the age range of 8 to 14 years with mandibular retrusion were divided into a treatment (n = 20) and control (n = 18) group. Mandibular retrusion in the treatment group subjects was corrected by twin-block appliance. The effect of twin-block appliance on PAP and PPWT dimensions were evaluated from lateral cephalograms recorded prior-to and after 6 months of appliance therapy in the treatment group subjects and the changes were compared with the changes in the control group subjects. Student’s t-test was used for statistical analysis; P-value of 0.05 was considered a statistically significant level.ResultsThe depth of the oropharynx was increased significantly in the treatment group subjects (P < 0.001) as compared to the control group subjects (P < 0.05). The depth of the hypopharynx increased significantly in treatment group subjects (P < 0.01). The PPWT at the level of the nasopharynx, oropharynx, and hypopharynx were maintained in the treatment group subjects; whereas in control group subjects, the PPWT was further reduced although the changes were not statistically significant.ConclusionsCorrection of mandibular retrusion by twin-block appliance in class II malocclusion subjects increased the PAP dimensions and maintained the pre-treatment thickness of posterior pharyngeal wall.

BackgroundOne of the most undesirable side effects of comprehensive orthodontic treatment is white spot lesions (WSLs). Despite many attempts at prevention of WSLs, its prevalence remains very high on debonding. There are many agents like fluoride toothpastes, fluoride varnishes, and fluoride mouth rinses, and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) is frequently used for the remineralization of WSLs. However, there is no consensus in the literature with respect to the success rates of these agents. Thus, the present study was designed to evaluate the efficacy of fluoride toothpaste alone and in combination with fluoride varnish and CPP-ACP plus crème in the remineralization of post-orthodontic WSLs.MethodsForty-five subjects in the age range of 16–25 years having at least one post-orthodontic WSL were included in the study. All the subjects were randomly divided into three groups (toothpaste group, varnish group, and CPP-ACP group). The efficacy of various remineralizing agents on the remineralization of WSLs was evaluated clinically and by DIAGNOdent immediately after debonding and subsequently after 1, 3, and 6 months of their use.ResultsTwice daily use of fluoride toothpaste alone had no significant effect on remineralization of WSLs at various intervals of observations (P = 0.078). Application of fluoride varnish along with twice daily use of fluoride toothpaste for 6 months significantly decreased the severity of WSLs (P < 0.01). Twice daily use of CPP-ACP plus crème along with fluoride toothpaste had significant effect on remineralization of WSLs at the end of 6 months of observation (P < 0.05). Between the group comparison showed that the mean visual and DIAGNOdent scores at various time intervals of observations were decreased more when fluoride varnish and CPP-ACP crème were used in addition to daily use of fluoride toothpaste, but the differences were not statistically significant (P > 0.05).ConclusionsThe use of fluoride varnish and CPP-ACP plus crème in addition to twice daily use of fluoride toothpaste had no additional benefit in the remineralization of post-orthodontic WSLs.

The hypothesis is rejected. Sagittal mandibular development had significant effects on the dimensions of the awake pharyngeal airway passage.