Quantitative evaluation of vertical control in orthodontic camouflage treatment for skeletal class II with hyperdivergent facial type.

BACKGROUND: In this study, we sought to quantify the influence of vertical control assisted by a temporary anchorage device (TAD) on orthodontic treatment efficacy for skeletal class II patients with a hyperdivergent facial type and probe into the critical factors of profile improvement. METHODS: A total of 36 adult patients with skeletal class II and a hyperdivergent facial type were included in this retrospective case-control study. To exclude the effect of sagittal anchorage reinforcement, the patients were divided into two groups: a maxillary maximum anchorage (MMA) group (N = 17), in which TADs were only used to help with anterior tooth retraction, and the MMA with vertical control (MMA + VC) group (N = 19), for which TADs were also used to intrude the maxillary molars and incisors. The treatment outcome was evaluated using dental, skeletal, and soft-tissue-related parameters via a cephalometric analysis and cast superimposition. RESULTS: A significant decrease in ANB (P < 0.05 for both groups), the retraction and uprighting of the maxillary and mandibular incisors, and the retraction of protruded upper and lower lips were observed in both groups. Moreover, a significant intrusion of the maxillary molars was observed via the cephalometric analysis (- 1.56 ± 1.52 mm, P < 0.05) and cast superimposition (- 2.25 ± 1.03 mm, P < 0.05) of the MMA + VC group but not the MMA group, which resulted in a remarkable decrease in the mandibular plane angle (- 1.82 ± 1.38°, P < 0.05). The Z angle (15.25 ± 5.30°, P < 0.05) and Chin thickness (- 0.97 ± 0.45°, P < 0.05) also improved dramatically in the MMA + VC group, indicating a better profile and a relaxed mentalis. Multivariate regression showed that the improvement in the soft tissue was closely related to the counterclockwise rotation of the mandible plane (P < 0.05). CONCLUSIONS: TAD-assisted vertical control can achieve intrusion of approximately 2 mm for the upper first molars and induce mandibular counterclockwise rotation of approximately 1.8°. Moreover, it is especially important for patients without sufficient retraction of the upper incisors or a satisfactory chin shape.

The role of genotype and diet in shaping gut microbiome in a genetic vitamin A deficient mouse model.

Multifactors have been reported to affect the gut microbiome, including genotype, age, diet, and nutrition. However, few reports have investigated the relative capacity of different factors to shape the gut microbiome in a single study. Our design used a genetic vitamin A-deficient mouse model, the Rbp4-/- mouse, feeding with the low vitamin A diets at different ages of initiation (4 or 7 weeks) for 28 days. Fecal samples were collected for bacterial profiling at seven time points after diet controlling. With Rbp4 depletion, Akkermansia decreased and Bacteroides increased, whereas Desulfovibrio, Barnesiella, Clostridium_XlVa, and Lactobacillus fluctuated. The bacterial community swiftly adjusted with the vitamin A-deficient diet administration and gradually changed (e.g., decrease of Barnesiella and increase of Desulfovibrio). Age exerted a relatively weaker but long-last influence. At an earlier age to feed a vitamin A-deficient diet, a higher microbial dysbiosis index will be valued. Of note, the shaping effects of diet and age on the bacterial community varied with the difference of genotype, which might indicate a greater role of genotype than diet and age in shaping the gut microbiome.

Longitudinal Quantitation of Tooth Displacement in Chinese Adolescents with Normal Occlusion.

This longitudinal study aims to analyze the different modes of the maxillary and mandibular tooth displacement in subjects, who were aged 12.5-17.5 years (150-210 months), with untreated normal (Class I) occlusion. Longitudinal lateral cephalograms for a set of 10 subjects (7 females and 3 males) at consecutive annual time points were selected and monitored. Data were analyzed on the basis of the superimpositions of serial tracings of lateral cephalograms on stable anterior cranial base, the anatomies of the maxillary and mandibular structures. The horizontal and vertical displacements of the first molar and incisor were assessed by t-test. The local and the secondary tooth displacements with growth contributed to the total horizontal and vertical displacements of the molars and incisors of the subjects. In the total tooth displacement, the horizontal growth of maxilla and mandible had the same contribution as the local tooth displacements. The vertical maxillary growth played a smaller role than the local drift, and mandibular remodeling went in a reverse direction with the local tooth drift. The first molars moved more forward than the incisors in the upper and lower arches. Both the upper and lower first molars showed forward tipping. The analysis of tooth displacement may be utilized in making orthodontic treatment plan, including anchorage or torque control.

Chronic inflammation deteriorates structure and function of collagen fibril in rat temporomandibular joint disc.

Collagen is the building component of temporomandibular joint (TMJ) discs and is often affected by inflammation in temporomandibular disorders. The macromechanical properties of collagen are deteriorated by chronic inflammation. However, the mechanism by which inflammation influences disc function remains unknown. The relationship between the ultrastructure and nanomechanical properties of collagen in inflamed discs should be clarified. Seven-week-old female Sprague-Dawley rats were randomly divided into two groups. Chronic TMJ inflammation was induced by intra-articular injection of complete Freund's adjuvant, and samples were harvested after 5 weeks. Picrosirius staining revealed multiple colours under polarized light, which represented alternative collagen bundles in inflamed discs. Using atomic force microscopy scanning, the magnitude of Young's modulus was reduced significantly accompanied with disordered collagen fibril arrangement with porous architecture of inflamed discs. Transmission electron microscopy scanning revealed a non-uniform distribution of collagen fibres, and oversized collagen fibrils were observed in inflamed discs. Fourier transform infrared microspectroscopy revealed a decrease in 1 338 cm-1/amide II area ratio of collagen in different regions. The peak positions of amide I and amide II bands were altered in inflamed discs, indicating collagen unfolding. Our results suggest that sustained inflammation deteriorates collagen structures, resulting in the deterioration of the ultrastructure and nanomechanical properties of rat TMJ discs.

Miniscrew-assisted customized lingual appliances for predictable treatment of skeletal Class II malocclusion with severe deep overbite and overjet.

This report describes the use of miniscrew-assisted customized lingual fixed appliances in a patient with severe skeletal Class II malocclusion. The patient was a 12-year-old Chinese girl with the chief complaint of protrusive lips and anterior teeth. Her diagnosis included a skeletal Class II relationship with maxillary protrusion, a backward-rotated mandible, a full Angle Class II molar relationship, and severe deep overjet and overbite. Four premolars were extracted, and miniscrew anchorage was placed in the maxillary posterior lingual segment to provide maximum anchorage and to achieve vertical control of the intruding molars. The customized lingual fixed appliance and temporary anchorage devices created a smooth and invisible treatment progress, resulting ultimately in a well-aligned dentition with ideal intercuspation and a dramatically improved profile. The 3-year follow-up examination indicated that the excellent treatment outcome was stable.

Nonsurgical correction using miniscrew-assisted vertical control of a severe high angle with mandibular retrusion and gummy smile in an adult.

Orthodontic treatment in adult patients with a skeletal discrepancy can be challenging. In this case report, we achieved both sagittal and vertical control by combining the classic sliding mechanics straight-wire technique with miniscrew anchorage. We treated a 21-year-old Chinese woman with a severe high mandibular plane angle, a retrusive chin, and a gummy smile. Her diagnosis included a skeletal Class II skull base with a mild anterior open bite, a protrusive maxilla, and a backwardly rotated mandible. This case underscores the importance of anchorage control in both the sagittal and vertical directions. First, we used miniscrews in the maxillary and mandibular buccal segments to obtain rigid anchorage. Next, we achieved good anterior and posterior vertical control with miniscrews in the maxillary anterior labial and posterior buccolingual segments. Intrusion of the maxillary molars contributed to deepening of the anterior overbite and counterclockwise rotation of the mandibular plane, which, in turn, improved the facial profile. Intrusion of the maxillary incisors contributed to correction of the gummy smile. After 1 year of retention, the patient had a stable, well-aligned dentition with ideal intercuspation and an improved facial contour. Our results thus suggest that placement of miniscrews in the anterior and posterior regions of the maxilla is effective for camouflaging a high-angle skeletal Class II defect. This technique requires minimal patient compliance and is particularly useful for correction of a high angle in an adult with a gummy smile.

Nonsurgical correction of a severe anterior deep overbite accompanied by a gummy smile and posterior scissor bite using a miniscrew-assisted straight-wire technique in an adult high-angle case.

In the present report, we describe the successful use of miniscrews to achieve vertical control in combination with the conventional sliding MBT™ straight-wire technique for the treatment of a 26-year-old Chinese woman with a very high mandibular plane angle, deep overbite, retrognathic mandible with backward rotation, prognathic maxilla, and gummy smile. The patient exhibited skeletal Class II malocclusion. Orthodontic miniscrews were placed in the maxillary anterior and posterior segments to provide rigid anchorage and vertical control through intrusion of the incisors and molars. Intrusion and torque control of the maxillary incisors relieved the deep overbite and corrected the gummy smile, while intrusion of the maxillary molars aided in counterclockwise rotation of the mandibular plane, which consequently resulted in an improved facial profile. After 3.5 years of retention, we observed a stable, well-aligned dentition with ideal intercuspation and more harmonious facial contours. Thus, we were able to achieve a satisfactory occlusion, a significantly improved facial profile, and an attractive smile for this patient. The findings from this case suggest that nonsurgical correction using miniscrew anchorage is an effective approach for camouflage treatment of high-angle cases with skeletal Class II malocclusion.

Mesoporous silica nanospheres decorated with CdS nanocrystals for enhanced photocatalytic and excellent antibacterial activities.

Uniform SiO2@CdS mesoporous nanospheres with an average diameter of 300 nm have been synthesized successfully by a facile process. The as-prepared mesoporous composite nanospheres have a BET-specific surface area of 640 m(2) g(-1) and an average pore size of 2.82 nm. The results demonstrated that more than 60% Rhodamine B (RhB) dye in solution (4.8 mg L(-1), 50 mL) could be removed by adsorption in the dark for 30 min using the as-prepared SiO2@CdS mesoporous nanospheres (40 mg). The as-prepared SiO2@CdS mesoporous nanospheres have a mesoporous nanostructure, suggesting a higher specific surface area and resulting in a strong adsorption ability. In addition, the mesoporous silica was decorated with ca. 5 nm CdS nanocrystals, which showed excellent photocatalytic activity under visible light and could rapidly remove most of the RhB molecules from a pollutant solution under visible light irradiation. Furthermore, the mesoporous SiO2@CdS nanospheres synthesized by the present protocol exhibited excellent antibacterial activity.

Progression of cartilage degradation, bone resorption and pain in rat temporomandibular joint osteoarthritis induced by injection of iodoacetate.

BACKGROUND: Osteoarthritis (OA) is an important subtype of temporomandibular disorders. A simple and reproducible animal model that mimics the histopathologic changes, both in the cartilage and subchondral bone, and clinical symptoms of temporomandibular joint osteoarthritis (TMJOA) would help in our understanding of its process and underlying mechanism. OBJECTIVE: To explore whether injection of monosodium iodoacetate (MIA) into the upper compartment of rat TMJ could induce OA-like lesions. METHODS: Female rats were injected with varied doses of MIA into the upper compartment and observed for up to 12 weeks. Histologic, radiographic, behavioral, and molecular changes in the TMJ were evaluated by light and electron microscopy, MicroCT scanning, head withdrawal threshold test, real-time PCR, immunohistochemistry, and TUNEL assay. RESULTS: The intermediate zone of the disc loosened by 1 day post-MIA injection and thinned thereafter. Injection of an MIA dose of 0.5 mg or higher induced typical OA-like lesions in the TMJ within 4 weeks. Condylar destruction presented in a time-dependent manner, including chondrocyte apoptosis in the early stages, subsequent cartilage matrix disorganization and subchondral bone erosion, fibrosis, subchondral bone sclerosis, and osteophyte formation in the late stages. Nociceptive responses increased in the early stages, corresponding to severe synovitis. Furthermore, chondrocyte apoptosis and an imbalance between anabolism and catabolism of cartilage and subchondral bone might account for the condylar destruction. CONCLUSIONS: Multi-level data demonstrated a reliable and convenient rat model of TMJOA could be induced by MIA injection into the upper compartment. The model might facilitate TMJOA related researches.

[Study on oral Candida albicans apoptosis in vitro].

PURPOSE: Candida albicans is one of the main opportunistic pathogen for human , the aim of this study is to investigate the phenomena of apoptosis in oral Candida albicans induced by acetic acid. METHODS: The Candida albicans of clinical strains were induced to apoptosis by using a weak acid acetic acid.The apoptosis was detected by flow cytometry and TEM. The data were processed for Chi-square test using SPSS11.5 software package. RESULTS: Oral Candida albicans had classic apoptosis when induced by proper concentration of acetic acid, and different concentrations of acetic acid had variable ability of inducing apoptosis of Candida albicans. CONCLUSIONS: Apoptosis can be detected in clinical strains of Candida albicans, the mechanism of apoptosis needs further research for the purpose of developing new antifungal drugs. Supported by National Natural Science Foundation of China(Grant No.30400498) and 2007 National College Student Innovative Planning Project.