Orthodontic Waves最新文献

Purpose

To compare treatment effects of Class II elastics and anterior mandibular position training against fixed Class II corrector (PowerScope™) during the correction of skeletal Class II malocclusion with fixed appliance in growing patients.

Materials and methods

Thirty-six growing patients with skeletal Class II malocclusion with a retruded pogonion position were randomly allocated to the Class II elastics or PowerScope™ groups. Preadjusted edgewise fixed appliances were used in both treatment groups. Skeletal, dental and profile changes were compared using lateral cephalograms taken before (T₀), after initial alignment (T₁) and after Class I obtained (T₂) for 16/18 patients in the Class II elastics group and 15/18 patients in the PowerScope™ group.

Results

The duration of treatment was significantly longer for the Class II elastics group than PowerScope™ group. In terms of skeletal changes, Class II elastics increased mandibular length, midfacial length and mandibular plane angle significantly more than the PowerScope™. In terms of dental changes, Class II elastics increased dental height significantly more than the PowerScope™.

Conclusions

Both treatment modalities reduced severity of Class II malocclusion and decreased profile convexity. Class II elastics with anterior mandibular position training increased mandibular length more but required longer treatment duration. The PowerScope™ had a greater effect on maxillary dento-alveolar restriction. (ClinicalTrials.in.th: TCTR 20180220003).

Purpose

Mechanical stimuli induce the proliferation and osteogenic differentiation of periodontal ligament (PDL) progenitor cells. However, the localization of formative and proliferative cells in response to orthodontic force in the PDL is unknown. We aimed to elucidate the expression patterns and localization of the cell proliferation- and osteogenesis-associated markers in the PDL during tooth movement.

Materials and methods

Five-week-old male Sprague–Dawley rats had their right maxillary first molars (rM1s) moved mesially using a 10-gf titanium-nickel alloy closed-coil spring. Left maxillary first molars (lM1s) served as controls. Immunohistochemical analyses of leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5), Ki67, and runt-related transcription factor 2 (RUNX2) were performed in the periapical region of M1. mRNA levels of Ki67, Runx2, and β-catenin were quantified by real-time reverse transcription polymerase chain reaction (qRT-PCR). In vitro human PDL stem cells (hPDLSCs) were cyclically stretched for 24 h, and MTT assay and western blot analysis of LGR5 were performed.

Results

Immunohistochemistry showed that LGR5 and Ki67 were partially co-expressed with RUNX2 in the periapical PDL. Immunoreactivities of LGR5, Ki67, and RUNX2 were significantly greater in the PDL of the rM1 than in that of the lM1 on day 3. qRT-PCR showed that Ki67 and Runx2 mRNA levels, but not β-catenin levels, increased on the mesial side of the periapical PDL on day 3. Western blot analysis revealed that 24 h of cyclic strain stimulated LGR5 expression in hPDLSCs.

Conclusion

Our findings suggested that orthodontic force induced LGR-5- and Ki67-positive cells expressing RUNX2 in the PDL during tooth movement.

Purpose

Chronic nasal obstruction is known to decrease blood oxygen saturation. Mouth breathing in association with chronic nasal obstruction leads to the collapse of the buccinator mechanism and to a clockwise rotation of the mandible, which causes mandibular retrusion. This study aimed to investigate the influences of nasal obstruction on the morphological and histological changes of the mandible in growing rats.

Materials and methods

Thirty 8-day-old male Wistar rats were randomly divided into the control and experimental groups. The experimental group underwent unilateral nasal obstruction by cauterization of the external nostrils at 8 days of age. Pulse oxygen saturation (SpO₂) was monitored every week. Rats were sacrificed at 9 weeks of age. The mandibular changes were analyzed via lateral cephalometric radiographs and micro-CT scans. We utilized toluidine blue and tartrate-resistant acid phosphatase (TRAP) staining for histological analysis. Immunohistochemical staining of hypoxia induced factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), osteoprotegerin (OPG) receptor activator of nuclear factor kappa-B ligand (RANKL) were also performed to reveal the mechanism of the morphological changes.

Results

SpO₂ was significantly lower in the experimental than in the control group. In the experimental group, length, bone mineral density and cartilage layer thickness of mandibular condyle were decreased. The number of TRAP-positive cells in the condyle, HIF-1α-positive cells, VEGF-positive cells and RANKL-positive cells in the condylar cartilage was significantly increased. In contrast, a reduced expression of OPG protein was observed in the experimental group.

Conclusions

Our findings suggest that unilateral nasal obstruction in the growth period affects mandibular morphology.

Purpose

To compare the characteristics and load-deflection graphs of 0.012″ heat-activated NiTi, superelastic NiTi and bent (bends placed at 1, 2 and 3 mm) superelastic NiTi wires, focusing on force at 0.5 mm after deactivation after deflection by 1, 2, 3 and 4 mm.

Materials and methods

Three-bracket bending tests using a 10 N load cell with 1 mm/min crosshead speed and 8 mm span were performed at 37 °C. Three groups of wires, 0.012″ heat-activated NiTi wires (HANT), superelastic NiTi wires (S), and superelastic NiTi wires with bends placed at 1, 2 and 3 mm (SB1, SB2 and SB3, respectively) were deflected by 1, 2, 3 and 4 mm. Deactivation forces (N) at 0.5 mm after deactivation were compared using ANOVA.

Results

Bent NiTi wires produced lighter forces than superelastic and heat-activated NiTi wires (P < 0.05). Superelastic and heat-activated NiTi wires had linear load-deflection graphs at 1 mm deflection. No bent NiTi wires had linear load deflection graphs; hysteresis was observed after 2, 3 and 4 mm deflection in all NiTi groups. Increasing the number of bends and deflection appeared to inactivate NiTi wires.

Conclusions

After any deflection, all bent NiTi wires produce lighter forces at 0.5 mm after deactivation than superelastic NiTi and heat-activated NiTi wires. This study indicates bending a NiTi wire close to a displaced tooth with up to 1 mm deflection can produce an active light deactivation force to level severely displaced teeth.

This case report describes the orthodontic treatment of a 13-year-old female patient with high-angle Class III malocclusion, including anterior open bite and impacted upper canine teeth with a convex soft tissue profile. In this case, preadjusted edgewise appliances were placed after the extraction of the upper deciduous canine teeth, impacted upper canine teeth and lower first premolars. The upper and lower dental arches were aligned using a temporary anchorage device (TAD) for retraction and intrusion of the lower incisors avoiding the extrusion of the lower molars. A good facial profile and occlusion were achieved after active treatment.

A 34-year-old female patient who had undergone surgical treatment for a cleft in the soft palate during childhood received orthodontic treatment for crowding. She had a straight type facial profile and facial asymmetry with a concave area on the left side of the philtrum and mandibular deviation to the left. The surgical scar was observed on the center of the palate. She also had a severely constricted maxillary arch and unilateral cross bite on the left side. In this report, we suggest a novel method for uneven maxillary lateral expansion using a dento-osseous-supported expansion appliance in the frontal side of the maxilla and a modified dental-supported expansion appliance in the mid-palatal area. With this method, we achieved the optimal maxillary expansion in the maxillary frontal and molar areas. As a result of the surgically-assisted orthodontic treatment, facial asymmetry, the facial midline, and severe malocclusion were corrected. Furthermore, the resulting occlusion and facial symmetry were maintained over a 2-year retention period. Although attention must be paid regarding the retention of the expanded maxillary bone, our findings in the present study suggest that differential maxillary lateral expand distraction osteogenesis, which is performed using combined expansion appliances, can be successfully performed in patients with cleft palate.

Purpose

To evaluate the effects of sex, skeletal age, sagittal skeletal pattern, and the interaction among these three factors on the pharyngeal airway widths and areas, and the positions and dimensions of surrounding structures.

Materials and methods

Pretreatment lateral cephalometric radiographs of 418 growing orthodontic patients (183 males, 235 females); 6–20 years old (mean age, 13.95 ± 3.62 years), were collected from 2007–2014, Department of Radiology, Faculty of Dentistry, and divided into 3 skeletal ages according to cervical vertebral maturation stages, pre-pubertal (cervical stages (CS) 1,2), pubertal (CS 3,4), and post-pubertal (CS 5,6). Ten angular, 13 linear, and 3 cephalometric area measurements were analyzed. Three-way ANOVA and Factor analysis were applied to compare sex, skeletal age, and sagittal skeletal pattern differences in the pharyngeal airway dimensions and the surrounding structure dimensions and positions.

Results

Sex–skeletal age interactions existed in the nasopharyngeal and oropharyngeal airway dimensions, and dimensions and positions (vertical, horizontal) of surrounding structures. Skeletal age–sagittal skeletal pattern interactions also affected the pharyngeal airway dimensions. In the post-pubertal period, male and skeletal Class III subjects tended to have larger pharyngeal airway, tongue, and soft palate dimensions; more anterior positions of the hyoid and tongue; and less obtuse soft palate angulation. The post-pubertal males also had more inferior positions of the hyoid and tongue.

Conclusion

Interactions between sex–skeletal age and skeletal age–sagittal skeletal pattern affected the pharyngeal airway dimensions. The surrounding structure positions and dimensions varied according to sex–skeletal age interaction and sagittal skeletal difference.

Purpose

To determine the relationship between the cranial base and both jaw bases in different skeletal patterns.

Materials and methods

Lateral cephalometric radiographs of 180 adult patients of all three malocclusion groups were evaluated and analyzed. A group of linear and angular measurements were measured and compared among all study groups to assess the existence of any relationship between the cranial base and both jaw base discrepancies.

Results

Significant differences were found in the cranial base angle (NSBa) and both jaw base lengths among all three malocclusion groups, while no significant differences were found in the cranial base lengths. As for angular measurements, an inverse correlation was found between the cranial base angle and both SNA and SNB angles in both Class II and Class III malocclusion groups. Concerning linear measurements, a significant correlation was found between the total cranial base length and the total facial height among all malocclusion groups.

Conclusion

The cranial base angle affects the anteroposterior orientation of both maxilla and mandible with a minimal contribution to the appearance of different vertical skeletal patterns. Meanwhile, the cranial base length affects minimally the anteroposterior orientation of both the maxilla and the mandible. However, a significant link was found between it and the total facial height, thus contributing to the appearance of different vertical skeletal patterns.

Purpose

A nationwide collaborative survey was performed in Japan to evaluate the recent treatment outcomes on occlusion after orthodontic/orthognathic treatment for patients with unilateral cleft lip and palate (UCLP).

Methods

A retrospective collaborative survey was performed. Twenty-five facilities, including 14 university hospitals, examined their orthodontic records and cast models of patients with UCLP. Using common format, information of 492 non-syndromic UCLP cases were reported. Patients with syndromic UCLP or congenital missing maxillary central incisors were excluded. Basically, each facility reported their most recent 30 cases.

Results

Of 492 cases, 330 cases (67.1%) were reported from 11 facilities, suggesting that orthodontic treatment for patients with CL/P was not fully centralized in Japan. Secondary alveolar bone grafting and orthognathic surgery were performed in 92.7% and 22.5% of cases, respectively. A significantly higher rate of orthognathic surgery was seen in cases reported from university hospitals (27.5%) than other facilities (14.8%). Average age at the end of active orthodontic/orthognathic treatment was 18.5 years. The lateral incisors on cleft sides were congenitally missing in 50.2% and displayed microdontia in 42.9% of cases. After orthodontic treatment, the central incisors and the canines were aligned without interdental spaces in 55.3% of cases. The positive anterior overjet was seen in 88.2%, and the centerline discrepancies between maxillary and mandibular incisors within 1/4 of mandibular incisor width was in 74.8% of cases.

Conclusions

The final occlusion after orthodontic treatment was satisfactory in most cases. Findings of this study are referable for improving standard Japanese orthodontic care for patients with CL/P.