Effect of wearing cervical headgear on tongue pressure

Changes in lips, cheeks and tongue pressures after upper incisor protrusion in Class II division 2 malocclusion: a prospective study

Background

The etiology of Class II division 2 (CII/2) malocclusion focuses on heredity; however lip, cheek, and tongue pressures that are associated with the environmental effect are considered to have an effect. The aim of this study was to evaluate the relation between perioral pressures and the upper incisor inclination in CII/2 malocclusion.

Methods

Twenty patients (8 females, 12 males; mean age 10.29 ± 0.90 years) with CII/2 malocclusion were included in the study group, and 15 patients (5 females, 10 males; mean age 10.56 ± 1.06 years) with Class I malocclusion were included. The upper incisors were protruded with a utility arch (0.016 × 0.022 in. blue elgiloy wire). Perioral pressure assessment was made with the Iowa Oral Pressure Instrument. Upper lip pressure, lower lip pressure, vertical lip pressure, left-right buccal pressures, swallowing, and maximum tongue pressures were measured. Repeated measure ANOVA was used to test the intragroup differences. Intergroup comparisons were made using two-way repeated measure ANOVA with Bonferroni correction. Relationships between the variables were analyzed using rank correlation (Spearman’s rho). The significance for all statistical tests was predetermined at p < 0.05.

Results

A significant change occurred in the upper lip pressure, lower lip pressure, and vertical lip pressure; however, significant difference was not found between the groups. Upper lip pressure increased significantly in both groups. In the CII/2 group, lower lip pressure increased after protrusion and decreased after retention, while vertical lip pressure decreased and then increased significantly. Left buccal pressure changes between the groups were not parallel. Right buccal pressure, swallowing, and maximum tongue pressure changes were not statistically significant. Statistically significant correlation was found between U1-NA (mm) and vertical lip pressure (r −0.467).

Conclusions

In the CII/2 group, upper lip pressure increased only in retention. Lower lip pressure increased and vertical lip pressure decreased after protrusion. Nevertheless, these changes did not remain stable after the retention period. The difference between groups was not statistically significant at the end of retention.

Horizontal and vertical changes in anchor molars after extractions in bimaxillary protrusion cases

Objective

To evaluate changes in the anchor molar position (horizontal, vertical) after retraction in bimaxillary protrusion maximum anchorage cases.

Materials and Methods

Thirty patients requiring maximum anchorage after extraction of the first premolars were selected for this study. The second molars were banded in both arches along with trans-palatal arch in the maxillary arch and lingual arch in the mandibular arch. En mass retraction was done using sliding mechanics. Horizontal and vertical positions of the anchor first molars were evaluated cephalometrically before and after orthodontic retraction.

Results

In the horizontal plane, maxillary first molars showed net mesial movement of 1.72 mm, and there was a statistical difference between the pre- and post-values (P < 0.001). The mandibular molars showed a net horizontal movement of 2.26 mm, and there was a statistically significant difference between the pre- and post-values (P < 0.001). In the vertical plane, there was vertical movement of the maxillary anchor molars by a net value of 0.95 mm which was statistically significant (P < 0.001). The mandibular anchor molars moved vertically by a net value of 0.45 mm. This difference was statistically not significant.

Conclusion

There was anchorage loss seen in both the planes (horizontal, vertical) of the maxillary anchor molars. In the mandibular anchor molars, there was anchorage loss seen only in the horizontal plane. No anchorage loss was seen in the vertical plane.

A comparative anchorage control study between conventional and self-ligating bracket systems using differential moments

OBJECTIVE

To compare the efficiency in anchorage preservation of conventional and self-ligating brackets after the extraction of first maxillary premolars using differential moment mechanics.

MATERIALS AND METHODS

Thirty-eight patients requiring extraction of maxillary first premolars and maximum anchorage during space closure were evaluated based on bracket type. Group 1, comprising 23 patients, was bonded with preadjusted conventional brackets (CBs) with a slot of 0.022-inch × 0.030-inch. Group 2 comprised 15 patients who were bonded with 0.022 inch preadjusted self-ligating brackets (SLBs). Patients in both groups received a nickel titanium (NiTi) intrusion arch and a 150 g NiTi closing coil spring for separate canine retraction, followed by a continuous mushroom loop archwire to retract the incisors. Lateral cephalograms were available at the start of treatment (T1) and at the completion of space closure (T2). Statistical comparisons were performed with paired and unpaired Student's t-tests.

RESULTS

No significant differences were found between the groups in maxillary molars anchorage loss (3.87 ± 1.35 mm and 3.65 ± 1.73 mm for the CB and SLB groups, respectively). Only the mean vertical movement of the tip of the incisor was significantly different between the groups (CB  =  -0.92 ± 1.46 mm; SLB  =  0.56 ± 1.65 mm).

CONCLUSION

There were no significant differences in the amount of anchorage loss of the maxillary first molars between SLB and CB systems during space closure using differential moments.

Tongue strength of healthy young adults

The measurement of tongue strength contributes to the study of oro-facial physiology. The objective of this study was to investigate the influence of gender on tongue strength in young adults and to determine the differences in this strength between tongue regions. This study was conducted on 50 healthy volunteers (17 men and 33 women) with a mean age of 23 years, with no oro-facial myofunctional alterations. The strength of the anterior portion and of the dorsum of the tongue was analysed with a calibrated electronic dynamometer. The subjects were asked to apply maximum force. Men showed higher tongue strength values than women both in the anterior portion and in the dorsum of the tongue (P<0·05), and the strength of the anterior portion of the tongue was lower than that of the dorsum in both genders (P<0·05). We conclude that gender and region influenced tongue strength.

Distal molar movement with Kloehn headgear: is it stable?

The aim of this study was to evaluate intramaxillary molar movement after 8 months of cervical traction and posttreatment displacement 7 years later. The total molar displacements in relation to stable intraosseous reference points were compared with those observed in an untreated control group that also had intraosseous reference indicators inserted. During the headgear period, the type of molar displacement could be predicted by the direction of the force system acting on the teeth. It was noted, however, that the variation in the vertical development was related more to each patient's growth pattern than to the force system applied. After cessation of the headgear, intramaxillary displacement of the molars was noted, and the total displacement of the molars did not differ from that of the untreated group. The indication for intramaxillary displacement of the molars by means of extraoral traction is therefore questioned.