Force-induced Caspase-1-dependent pyroptosis regulates orthodontic tooth movement.

Pyroptosis, an inflammatory caspase-dependent programmed cell death, plays a vital role in maintaining tissue homeostasis and activating inflammatory responses. Orthodontic tooth movement (OTM) is an aseptic force-induced inflammatory bone remodeling process mediated by the activation of periodontal ligament (PDL) progenitor cells. However, whether and how force induces PDL progenitor cell pyroptosis, thereby influencing OTM and alveolar bone remodeling remains unknown. In this study, we found that mechanical force induced the expression of pyroptosis-related markers in rat OTM and alveolar bone remodeling process. Blocking or enhancing pyroptosis level could suppress or promote OTM and alveolar bone remodeling respectively. Using Caspase-1-/- mice, we further demonstrated that the functional role of the force-induced pyroptosis in PDL progenitor cells depended on Caspase-1. Moreover, mechanical force could also induce pyroptosis in human ex-vivo force-treated PDL progenitor cells and in compressive force-loaded PDL progenitor cells in vitro, which influenced osteoclastogenesis. Mechanistically, transient receptor potential subfamily V member 4 signaling was involved in force-induced Caspase-1-dependent pyroptosis in PDL progenitor cells. Overall, this study suggested a novel mechanism contributing to the modulation of osteoclastogenesis and alveolar bone remodeling under mechanical stimuli, indicating a promising approach to accelerate OTM by targeting Caspase-1.

Interdisciplinary 3D digital treatment simulation before complex esthetic rehabilitation of orthodontic, orthognathic and prosthetic treatment: workflow establishment and primary evaluation.

BACKGROUND: An interdisciplinary treatment simulation and smile design before a complex esthetic rehabilitation is important for clinicians' decision-making and patient motivation. Meanwhile, intervention and interaction are necessary for dental specialists in these complex rehabilitations. However, it is difficult to visualize an interdisciplinary treatment plan by using the conventional method, especially when orthognathic surgery is involved, thus hindering communication between dental specialists. This research aims to establish a 3D digital workflow of interdisciplinary treatment simulation to solve this problem. METHODS: An interdisciplinary 3D digital workflow of simulated treatment plan for complex esthetic rehabilitation was established. Eleven patients were enrolled and illustrated with their treatment plans using 3D treatment simulation, as well as 2D digital smile design (DSD) plus wax-up. Visual analogue scales (VAS) were used to rate the intuitiveness, understanding, and satisfaction or help between the two methods by patients and dental specialists. RESULTS: According to the ratings from the patients, 3D treatment simulation showed obvious advantages in the aspects of intuitiveness (9.7 ± 0.5 vs 6.4 ± 1.4) and treatment understanding (9.1 ± 0.8 vs 6.6 ± 1.5), and the satisfaction rates were also higher (9.0 ± 0.6 vs 7.1 ± 1.8). Dental specialists regarded the 3D digital plans as more intuitive (8.9 ± 0.8 vs 5.9 ± 1.0) and useful to understand the plans from the other specialists (8.9 ± 0.7 vs 6.1 ± 1.0) and helpful to their own treatment plans (8.7 ± 0.9 vs 5.9 ± 1.4). CONCLUSIONS: The interdisciplinary 3D digital treatment simulation helps both patients and dental specialists to improve treatment understanding, and facilitates dental specialists for decision-making before complex esthetic rehabilitation. TRIAL REGISTRATION: This study was registered in the National Clinical Trials Registry under the identification number MR-11-20-002862. This is an observational study in which we did not assign the intervention.

Intrusion of overerupted maxillary molars with miniscrew implant anchorage: a radiographic evaluation.

The aim of this retrospective study was to quantitatively evaluate the treatment effects of intrusion of overerupted maxillary molars using miniscrew implant anchorage and to investigate the apical root resorption after molar intrusion. The subjects included 30 patients whose average ages were 35.5±9.0 years. All patients had received intrusion treatments for overerupted maxillary molars with miniscrew anchorage. There were 38 maxillary first molars and 26 maxillary second molars to be intruded. Two miniscrews were inserted in the buccal and palatal alveolar bone mesial to the overerupted molar. Force of 100-150 g was applied by the elastic chains between screw head and attachment on each side. Lateral cephalograms and panoramic radiographs taken before and after intrusion were used to evaluate dental changes and root resorption of molars. Only 6 of the 128 miniscrews failed. The first and second molars were significantly intruded by averages of 3.4 mm and 3.1 mm respectively (P<0.001). The average intrusion time was more than 6 months. The crown of the molars mesially tilted by averages of 3.1 degrees and 3.3 degrees (P<0.001) for first and second molars. The amounts of root resorption were 0.2-0.4 mm on average. The intrusion treatment of overerupted molars with miniscrew anchorages could be used as an efficient and reliable method to recover lost restoration space for prosthesis. Radiographically speaking, root resorption of molars was not clinically significant after application of intrusive forces of 200 to 300 g.

Measurement of cortical bone thickness in adults by cone-beam computerized tomography for orthodontic miniscrews placement.

The purpose of this study was to investigate the cortical bone thickness of the inter-dental area of both jaws for orthodontic miniscrew placement. The cone-beam computerized tomography images of 32 non-orthodontic adults with normal occlusion were taken to measure the cortical bone thickness in both jaws. One-way analysis of variance (ANOVA) was used to analyze the differences in cortical bone thickness. Buccal cortical bone in the mandible was thicker than that in the maxilla. In the maxilla, cortical bone thickness was thicker in the buccal side than in the palatal side. Buccal cortical bone thickness in the mandible was thickest at the site distal to the first molar, and in the maxilla it was thickest at the site mesial to the first molar, while in the palatal side of maxilla it was thickest at the site mesial to the second premolar. The changing pattern of cortical bone thickness varies at different sites. In the buccal side of maxilla, the thinnest cortical bone thickness was found to be at 4 mm level from the alveolar crest, while the thickest was at 10 mm level (except for the site mesial to the first premolar). The buccal cortical bone thickness at the sites mesial or distal to the first molar in the mandible and palatal cortical bone thickness of maxilla tended to increase with increasing distance from the alveolar bone.

[Evaluation of palatal bone thickness in adults with normal occlusion for orthodontic miniscrews placement].

OBJECTIVE: To investigate the palatal bone thickness in adult with normal occlusion. METHODS: The cone beam computerized tomography records of 32 adults with normal occlusion (16 males and 16 females), mean age (30.1 ± 6.5) years, were used to measure the bone thickness at midpalatal area and the right and left palatal sides. Coronal slices at 3 mm intervals were generated. Slice 1 was the coronal slice through the posterior border to the incisive foramen, while Slice 7 was the coronal slice 18 mm away from the incisive foramen. At each coronal slice, the midpalatal sites were Site M and the sites on the exterior margin of the hard palatal were Site D. Four equally divided parts on the line linking Site M to Site D were named Site A, B, C from the interior to the exterior respectively. Palatal bone thickness were measured at these sites. RESULTS: Significant differences were noted from Slice 1 to Slice 7, the bone thickness of palate tended to decrease from the front to the back. The thickest site at hard palatal was 12.6 mm, locating at Site D of Slice 1, while the thinnest site was 2.7 mm, locating at Site B of Slice 7. The palatal bone thickness ranged from 10.5 mm (maximum) to 5.8 mm (minimum) at Slice 2 and Slice 3. No statistical significance was found between the left and right sides (P > 0.05). CONCLUSIONS: The favorable sites for miniscrew placement were the anterior region of the hard palate in adult. The length of miniscrew ranged from 5 mm to 10 mm can be placed from 6 mm posterior to the incisive foramen.

Microscrew anchorage in skeletal anterior open-bite treatment.

OBJECTIVE: To evaluate the effectiveness of miniscrew anchorage for intrusion of the posterior dentoalveolar region to correct skeletal open bite. MATERIALS AND METHODS: The study was comprised of 12 patients (aged 14.3 to 27.2 years; mean 18.7 years) with anterior open bites. All the patients presented a Class II skeletal pattern and excessive posterior growth. Self-drilling miniscrew implants were inserted into the posterior midpalatal area and the buccal alveolar bone between the lower molars. A transpalatal and a lingual arch were used to maintain the molars on each side in order to avoid overrotation during intrusion. A force of 150 g was applied to the microscrews on each side to intrude the posterior teeth. Lateral cephalograms of all 12 patients were taken preintrusion and immediately after completion of the intrusion. The cephalometric films were measured and compared. RESULTS: The results showed that the anterior open bites in 12 patients were all corrected in a mean of 6.8 months. Overbite increased by a mean of 4.2 mm (P < .001), from -2.2 mm in preintrusion to 2.0 mm in postintrusion. The maxillary and mandibular first molars were intruded for an average of 1.8 mm (P < .001) and 1.2 mm (P < .001), respectively. The mandibular plane angle was reduced by 2.3 degrees (P < .001), which led to a counterclockwise rotation of the mandible with a significant decrease in the anterior facial heights (mean of 1.8 mm; P < .001). CONCLUSION: Miniscrew anchorage has the advantages of being a simpler procedure, being minimally invasive, and requiring minimal patient cooperation.

[Clinical application of miniscrew implant for maximum anchorage cases].

OBJECTIVE: The purpose of this study was to evaluate the efficiency of the self-drilling miniscrew implant for maximum anchorage cases. METHODS: The study comprised 5 patients whose ages ranged from 14 to 31 years. All patients presented with. Class II skeletal pattern, maxillary protrusion or bimaxillary protrusion. Maximum molar anchorage and first premolar extraction were required. In the stage of anterior teeth retraction, self-drilling miniscrew implants were inserted into the buccal alveolar bone between maxillary second premolar and first molar. Sliding mechanics with 150 - 200 g force was used to retract anterior teeth. The cephalometric films before and after retraction were measured. RESULTS: Dental protrusion and facial profile were improved significantly in all patients. The edge of upper incisors was retracted 6.4 mm and anchor molar moved anteriorly 0.3 mm averagely. All miniscrew implants remained stable during treatment and peri-implant soft tissue remained healthy. CONCLUSIONS: Self-drilling minisrcew implant could be used as an efficient method for anchorage control and an alternative choice of extra-oral forces.