Evaluation of the effects of the hybrid Pendulum in comparison with the conventional Pendulum appliance

Retrospective comparison of two different miniscrew-supported molar distalization methods applied in the buccal and palatal regions

BACKGROUND

To compare dentofacial effects of distalization with miniscrew-supported pendulum and infrazygomatic crest miniscrews.

METHODS

The study included 36 patients whose lateral cephalometric radiographs were obtained before (T0) and after (T1) distalization. Patients were divided into two groups according to the treatment methods: 1) distalization with miniscrew-supported pendulum (MSP) (n = 19; 14 girls and 5 boys; mean age 16.9 ± 1.46 years) and 2) distalization with infrazygomatic crest (IZC) miniscrews (n = 17; 8 girls and 9 boys; mean age 17.0 ± 1.68 years). Dental, skeletal and soft tissue measurements were performed on lateral cephalograms taken from individuals.

RESULTS

A significant molar distalization was achieved both in the MSP group (3.52 ± 0.76 mm at 8.71 ± 2.02 months) and the IZC group (3.5 ± 0.74 mm at 9.7 ± 2.5 months) (P < 0.001 for both). Premolar distalization was significantly lower in the MSP group (1.73 ± 1.09 mm) than in the IZC group (2.81 ± 0.79 mm) (P < 0.01). Significant molar tipping was observed in both groups (P < 0.001), while no significant difference was found between the groups (P > 0.05). Retrusion of maxillary incisors were significantly higher in the IZC group (2.75 mm) than in the MSP group (0.98 mm) (P < 0.01). A significant difference was found between the two groups with regard to the changes in overjet and overbite (P < 0.05).

CONCLUSIONS

Both distalization methods were found to be effective in achieving a Class I molar relationship in patients with Class II malocclusion.

Evaluation of Palatal Bone Thickness at the Implantation Areas of Two Popular Bone-Anchored Distalizers-A Cone Beam Computed Tomography Retrospective Study

Since class II malocclusion and lack of space within the dental arch due to early loss of deciduous molars is a common orthodontic problem in the Polish population, bone-anchored distalizers are becoming more and more popular. The aim of the present study was to evaluate palatal soft and hard tissue thickness using cone beam computed tomography (CBCT) at the area of micro-implant placement of two appliances for maxillary first molar distalization: Beneslider and TopJet distalizer. The study data were 100 consecutively selected CBCT images (53 of men and 47 of women). Measurements of bone and mucosa thickness were performed at six locations in the palate and tested according to their correlation with sex and age. The biggest bone and mucosa thickness were recorded in the insertion site of the TopJet miniscrew. Bone thickness in all points of paramedian insertion was significantly greater in males and the mean difference was approximately 1-1.8 mm. Age correlates significantly (p < 0.05) and positively (r > 0) with the thickness of the mucosa at all points: the older the patient, the thicker the mucosa at each measurement point. Anatomical diversity of the hard palate in the population involves the need to perform bone and mucosa thickness measurements before palatal micro-implant placement.

Class II malocclusion treatment with a customized dual force distalizer

Intraoral distalizers associated with skeletal anchorage provide the major benefit of promoting molar distalization with minimum anchorage loss and patient cooperation. This case report presents the treatment of a 17-year-old female with Class II Division 2 malocclusion, maxillary dentoalveolar protrusion, mild mandibular retrusion, increased overjet, deepbite, and lip incompetence. The treatment plan involved initial maxillary molar distalization with a customized version of the skeletally anchored dual force distalizer (DFD). The customized DFD used smaller mini-implants and included a fixed anterior biteplane. The device applied simultaneous forces from the buccal and palatal sides directly to the molars using nickel-titanium coil springs and allowed orthodontic mechanics in the mandibular teeth. An overcorrected Class I molar relationship was obtained after 6 months. After the distalization phase, retraction mechanics began with retraction loops and using a modified transpalatal bar reinforced with the mini-implants as anchorage. Moreover, the finishing phase was performed with multiloop edgewise archwires and intermaxillary elastics to enable an individualized control of each tooth. Total treatment time comprised 2 years 4 months, and significant improvements regarding the facial and occlusal perspectives were noticed. Similarly, these favorable changes remained stable during the 2-year follow-up period. The customized version of the skeletally anchored DFD followed by fixed appliances showed effectiveness and stability in Class II malocclusion treatment.