Effect of computer-assisted design and manufacturing cutting and drilling guides accompanied with pre-bent titanium plates on the correction of skeletal class II malocclusion: a randomized controlled trial

Comparison of fixed braces and clear braces for malocclusion treatment

BACKGROUND

To study and compare the effects of clear aligners without brackets and traditional fixed aligners in orthodontic treatment.

METHODS

The samples were collected from January 2022 to April 2023. The control group (n = 26) received orthodontic treatment using traditional fixed appliances. The research group (n = 20) received orthodontic treatment using the clear aligners without brackets. Compare the therapeutic effects and related evaluation indicators between two groups.

RESULTS

The total effective ratio was compared between the 2 groups, and the study group was greater(P < 0.05). After treatment, the detected values of the periodontal condition indicators (plaque index, debris index, and gingival bleeding index), serum inflammatory factors (CRP, IL-6 and TNF-α) of the two groups, were less than before, also were all less than the control group. (P < 0.05). After therapy, in comparison of the control group, the value of mastication efficiency, comfort and psychological evaluation, sleep indicators and the points of the four dimensions of life quality in the study group was greater, and the detection results were obviously greater than before(P < 0.05).

CONCLUSION

In the orthodontic therapy of sufferers with malocclusion, compared with the traditional fixed appliance, the clear aligners without brackets can enhance the treatment effects, improve the periodontal condition and masticatory function, and reduce the inflammatory responses, so that patients can feel more comfortable, thereby improving their psychology, sleep and quality of life. In the future, with the continual advancement of technology and people's pursuit of beauty, the application of clear aligners without brackets in orthodontic treatment will become more and more extensive. The continuous introduction of new materials and new technologies will further improve the effects and comfort of the clear aligners without brackets, reduce treatment time and discomfort, and also reduce patients' resistance to aligners, bringing patients a better treatment experience.

Accuracy and influencing factors of maxillary and mandibular repositioning using pre-bent locking plates: a prospective study

In-house repositioning methods based on three-dimensional (3D)-printing technology and the use of pre-bent plates has been gaining popularity in orthognathic surgery. However, there remains room for further improvement in methods and investigations on clinical factors that affect accuracy. This single-centre, prospective study included 34 patients and aimed to evaluate the accuracy and factors influencing maxillary and mandibular repositioning using pre-bent locking plates. The plates were manually pre-bent on the 3D-printed models of the planned position, and their hole positions were scanned and reproduced intraoperatively with osteotomy guides. The accuracy of repositioning and plate-hole positioning was calculated in three axes with the set landmarks. The following clinical factors that affect repositioning accuracy were also verified: deviation of the plate-hole positioning, amount of planned movement, and amount of simulated bony interference. The median deviations of the repositioning and hole positioning between the preoperative plan and postoperative results were 0.26 mm and 0.23 mm, respectively, in the maxilla, and 0.69 mm and 0.36 mm, respectively, in the mandible, suggesting that the method was highly accurate, and the repositioning concept based on the plate hole and form matching was more effective in the maxilla. Results of the correlation test suggest that large amounts of bony interference and plate-hole positioning errors in the up/down direction could reduce mandibular repositioning accuracy.

Assessment of condylar positional changes in severe skeletal class II malocclusion after surgical-orthodontic treatment

OBJECTIVES

This study aimed to determine the positional changes in the condyle in the temporomandibular joint (TMJ) of severe skeletal class II malocclusion patients treated with surgical-orthodontics.

MATERIALS AND METHODS

The measurements of TMJ space in 97 severe skeletal class II malocclusion patients (20 males, 77 females, mean age, 24.8 years, mean ANB = 7.41°) were assessed using limited cone-beam computed tomography (LCBCT) images acquired before orthodontics (T0) and 12 months after surgery (T1). 3D remodeling of the TMJ and measurements of the anterior space (AS), superior space (SS), and posterior space (PS) were performed to determine the position of the condyle for each joint. All data were analyzed by t test, correlation analysis, and Pearson correlation coefficient.

RESULTS

The mean AS, SS, and PS values after the therapy changed from 1.684 to 1.680 mm (0.24%), 3.086 to 2.748 mm (10.968%), and 2.873 to 2.155 mm (24.985%), respectively. The decreases in SS and PS were statistically significant. Positive correlations were found in the mean AS, SS, and PS values between the right and left sides.

CONCLUSIONS

The combination of orthodontic and surgical treatment makes the condyle move counterclockwise in the TMJ in severe skeletal class II patients.

CLINICAL RELEVANCE

Studies of temporomandibular joint (TMJ) intervals changes in patients with severe skeletal class II after sagittal split ramus osteotomy (SSRO) are limited. The postoperative joint remodeling, resorption, and related complications remain unstudied.

Clinical Application of CAD/CAM-Guided Modified Dautrey's Procedure in Recurrent Temporomandibular Joint Luxation

This study aimed to introduce the clinical application of the CAD/CAM-guided modified Dautrey's procedure in recurrent anterior temporomandibular joint luxation and evaluate its clinical effects. Four selected patients were treated by the CAD/CAM-guided modified Dautrey's procedure and were followed-up to access their curative effect. Joint pain and sound, recurrence rate, mandibular function, maximum mouth opening (MMO), symptoms of facial nerve injury, and changes in zygomatic facial appearance were observed in postoperative follow-up. The followed-up period ranged from 3 months to 1 year with an average time of 7.5 months. There was no recurrence in all 4 patients, and no symptoms of facial nerve injury and zygomaticofacial appearance changes were found. All patients showed improvement in MMO, with a mean preoperative and postoperative MMO of 4.74 and 3.74 cm, respectively. All of them showed relief of joint pain or sound 3 months or more after the operation and could exercise mandibular normally. This results showed that the CAD/CAM-guided modified Dautrey's procedure was effective in the treatment of recurrent temporomandibular joint luxation and could be used as a good alternative treatment for it.