Immediate effects of plantar inputs on the upper half muscles and upright posture: a preliminary study.

This purpose of this study was to investigate the immediate effects of plantar inputs on both the upper half muscle activity (anterior temporal, masseter, digastric, sternocleidomastoid, upper and lower trapezius, cervical) and the body posture, by means of electromyography (EMG) and vertical force platform, respectively. Twenty four (24) healthy adults, between the ages of 24 and 31 years (25.3 +/- 1.9), with no history of craniomandibular disorder or systemic musculoskeletal dysfunction, were randomly divided into two groups: test group (fourteen subjects) and control group (ten subjects). A first recording session (TO) measured the baseline EMG and postural patterns of both groups. After this session, the test group wore test shoes with insoles that stimulated the plantar surfaces, while the control group wore placebo shoes. After one hour, a second set of measurements (T1) were performed. Significant differences between the groups at baseline were observed in the left anterior temporal, left cervical, and left upper trapezius, as well as at T1 in the left anterior temporal and right upper trapezius (p < 0.05). Within-test group analysis showed a significant increase of the right upper trapezius activity (p < 0.05), whereas no changes were found by within-control group analysis. Lower risk of asymmetric muscle patterns and postural blindness in the test group compared to the control group was observed. Further studies are warranted to investigate the short and long-term effects of this type of insole, in patients with both craniomandibular-cervical and lower extremity disorders.

Evaluation of maxillary molar distalization with the distal jet: a comparison with other contemporary methods.

Maxillary molar distalization is an increasingly popular option for the resolution of Class II malocclusions. This communication describes the effects of one particular molar distalizing appliance, the distal jet, in a sample of 20 consecutively treated and growing subjects (11 females, nine males; mean starting age of 13) and compares these effects with those of similar devices. Pre- and postdistalization cephalometric radiographs and dental models were analyzed to determine the dental and skeletal effects. The distal jet appliances were constructed using a biomechanical couple to direct the distalizing force to the level of the maxillary first molar's center of resistance. The distal jet was the only appliance used during the distalization phase of treatment. Examination of the cephalometric tracings demonstrated that the crowns of the maxillary first molars were distalized an average of 3.2 mm into a Class I molar relationship. In the process, the first molars were tipped distally an average of 3.1 degrees, however, the amount of tipping in each case was influenced by the state of eruption of the second molar. In subjects whose second molars had erupted only to the level of the apical third of the first molar roots, distal tipping was almost twice that seen when the second molar had completed their eruption. Anchorage loss measured at the first premolars averaged 1.3 mm, but the crowns tipped 3.1 degrees distally because of the design of the appliance. The maxillary incisors were proclined an average of 0.6 degrees with minimal effect on the mandibular plane angle and lower facial height. This study suggests that the distal jet appliance effectively moves the maxillary molars distally into a Class I molar relationship with minimal distal tipping, however, some loss of anchorage is to be expected during this process. The distal jet appliance compares favorably with other intraoral distalization devices and with mechanics featuring mandibular protraction for the resolution of patients with Class II, despite the fact that these types of mechanics address different jaws.

Prevalence and distribution by gender of occlusal characteristics in a sample of Italian secondary school students: a cross-sectional study.

The aim of this study was to describe the prevalence and distribution, by gender, of occlusal traits in a sample of Italian students aged 11-14 years (mean 13 +/- 1 years). Using standardized and validated recording criteria, a single operator measured the overjet, overbite, open bite, anterior and posterior crossbites, crowding, coincidence of the upper and lower midlines, and diastema, in 810 secondary school students (53.6 per cent males). Chi-square, t-test statistics, and odds ratios (ORs) with 95 per cent confidence intervals (CI) were used to investigate the relationship between gender and malocclusion characteristic. Logistic regression was used to further analyse the independent association between gender and each outcome measure. Ninety-three per cent of the subjects showed at least one occlusal trait, with one or two anomalies recorded in 63 per cent of children. The prevalence of occlusal traits ranged from 1.1 (negative overjet) to 54 per cent (upper and lower midlines not coincident). Males were more likely than females to show both an increased overbite and an increased overjet, although the latter result was not confirmed by logistic regression (P = 0.05). Multivariate analysis showed a negative association between overbite and misalignment of the lower incisors and lack of coincidence of the upper and lower midlines, whereas subjects with an increased overbite were more likely to have an increased overjet (all P < 0.01). Further studies are required in order to further clarify these findings and to provide accurate estimates of the orthodontic treatment need in Italian adolescents.