Factors affecting local alveolar bone thickness in unilateral maxillary canine-lateral incisor transposition.

INTRODUCTION: This study aimed to use 3-dimensional data to investigate the factors affecting local alveolar bone thickness in unilateral maxillary canine-lateral incisor transposition. METHODS: Pretreatment cone-beam computed tomography data of 34 patients with unilateral maxillary canine-lateral transposition were imported into Dolphin Imaging software (version 11.8; Dolphin Imaging and Management Solutions, Chatsworth, Calif) for 3-dimensional reconstruction. The age, gender, and type of transposition at the beginning of treatment were recorded. The thickness and height of the transposed canine, the labiopalatal and distomedial distance from the transposed canine to the apex of the lateral incisor, the inclination of the transposed lateral incisor, the apical height of the lateral incisor, and the alveolar bone thickness in the apical plane were measured. Multiple linear regression analyses were applied to investigate the factors affecting alveolar bone thickness in the apical plane of the transposed lateral incisor. Two sample t test were applied to assess the difference of alveolar bone thickness in patients of different ages. RESULTS: The 10 boys and 24 girls had a mean age of 12.26 ± 2.34 years. In all 34 participants, the apical alveolar bone thickness of transposed lateral incisors was significantly higher than that of the unaffected side (P <0.05). Based on multiple regression analyses, factors associated with a wider alveolar bone thickness were as follows: age (ß = -0.237; P = 0.008), the labiopalatal distance from the transposed canine to the apex of the lateral incisor (ß = 0.675; P <0.001), and the inclination of the transposed lateral incisor (ß = 0.048; P = 0.032). Patients aged <11 years had significantly thicker alveolar bone than that of patients aged >11 years (P <0.05). CONCLUSIONS: Patients with younger age, greater lateral incisor inclination, and greater labiopalatal distance between canine and lateral incisor had more alveolar bone thickness. Early treatment permits tooth movement within the thicker alveolar bone.

Neighboring Carboxylic Acid Boosts Peroxidase-Like Property of Metal-Phenolic Nano-Networks in Eradicating Streptococcus mutans Biofilms.

Developing nature-inspired nanomaterials with enzymatic activity is essential in combating bacterial biofilms. Here, it is reported that incorporating the carboxylic acid in phenolic/Fe nano-networks can efficiently manipulate their peroxidase-like activity via the acidic microenvironment and neighboring effect of the carboxyl group. The optimal gallic acid/Fe (GA/Fe) nano-networks demonstrate highly enzymatic activity in catalyzing H2 O2 into oxidative radicals, damaging the cell membrane and extracellular DNA in Streptococcus mutans biofilms. Theoretical calculation suggests that the neighboring carboxyl group can aid the H2 O2 adsorption, free radical generation, and catalyst reactivation, resulting in superb catalytic efficiency. Further all-atom simulation suggests the peroxidation of lipids can increase the cell membrane fluidity and permeability. Also, GA/Fe nano-networks show great potential in inhibiting tooth decay and treating other biofilm-associated diseases without affecting the commensal oral flora. This strategy provides a facile and scale-up way to prepare the enzyme-like materials and manipulate their enzymatic activity for biomedical applications.

Functionalized MoS2-nanosheets with NIR-Triggered nitric oxide delivery and photothermal activities for synergistic antibacterial and regeneration-promoting therapy.

Bacterial infection in skin and soft tissue has emerged as a critical concern. Overreliance on antibiotic therapy has led to numerous challenges, including the emergence of multidrug-resistant bacteria and adverse drug reactions. It is imperative to develop non-antibiotic treatment strategies that not only exhibit potent antibacterial properties but also promote rapid wound healing and demonstrate biocompatibility. Herein, a novel multimodal synergistic antibacterial system (SNO-CS@MoS2) was developed. This system employs easily surface-modified thin-layer MoS2 as photothermal agents and loaded with S-nitrosothiol-modified chitosan (SNO-CS) via electrostatic interactions, thus realizing the combination of NO gas therapy and photothermal therapy (PTT). Furthermore, this surface modification renders SNO-CS@MoS2 highly stable and capable of binding with bacteria. Through PTT's thermal energy, SNO-CS@MoS2 rapidly generates massive NO, collaborating with PTT to achieve antibacterial effects. This synergistic therapy can swiftly disrupt the bacterial membrane, causing protein leakage and ATP synthesis function damage, ultimately eliminating bacteria. Notably, after effectively eliminating all bacteria, the residual SNO-CS@MoS2 can create trace NO to promote fibroblast migration, proliferation, and vascular regeneration, thereby accelerating wound healing. This study concluded that SNO-CS@MoS2, a novel multifunctional nanomaterial with outstanding antibacterial characteristics and potential to promote wound healing, has promising applications in infected soft tissue wound treatment.

The evaluation of lateral incisor adjacent to treated labial inversely impacted maxillary central incisor: A retrospective follow-up study.

INTRODUCTION: This retrospective study aimed to evaluate the further development of the lateral incisor and its associated periodontium adjacent to the treated labial inversely impacted maxillary central incisor. METHODS: We enrolled 23 participants (average age, 8.24 ± 1.43 years) undergoing a mean follow-up period of 31.10 ± 13.05 months. Each participant had an unimpacted lateral incisor and a successfully treated unilateral labial inversely impacted maxillary central incisor. The contralateral lateral incisors served as controls. Cone-beam computed tomography data were available for treatment completion and follow-up stages. The variables (including root length, dental age, root canal width, root-crown angulation, and alveolar bone loss and thickness) were evaluated with Dolphin Imaging software (version 11.95; Dolphin Imaging and Management Solutions, Chatsworth, Calif). RESULTS: At the follow-up stage, the lateral incisors in the impacted side had significantly longer root lengths, smaller root canal widths, and thinner labial bone widths at the apex than at the posttreatment stage (P <0.001, P = 0.036, and P = 0.001, respectively). A significant lateral incisor root length reduction was noted when comparing the impacted and contralateral sides, although no variation was observed in root canal width. Similarly, crown-root angulation of the lateral incisor on the impacted side was significantly larger than that of the contralateral lateral incisor. The lateral incisor on the impacted side also had thicker labial and thinner lingual bone widths at the apex than the contralateral lateral incisor. CONCLUSIONS: The lateral incisor adjacent to the successfully treated labial inversely impacted maxillary central incisor showed continuous growth during follow-up stages, exhibiting a similar morphology and alveolar bone quality but shorter root length, larger root angulation, and thinner lingual bone width at the apex than those of the contralateral lateral incisors.

Morphometric evaluation of alveolar bone after orthodontic treatment of multiple impacted teeth in the unilateral maxillary anterior region.

INTRODUCTION: This study aimed to investigate the height and thickness of alveolar bone by cone-beam computed tomography imaging after orthodontic treatment in the unilateral maxillary anterior region and speculate on reasons for the difference in alveolar bone morphology. METHODS: This study selected 11 patients (3 males and 8 females; mean age, 9.42 ± 1.45 years). Cone-beam computed tomography was performed for these 11 patients before and after treatment using Dolphin Imaging software (Dolphin Imaging and Management Solutions, Chatsworth, Calif). Labial and palatal alveolar bone thickness (BT) at root apices and different levels along the roots and loss of alveolar bone height was measured for each impacted tooth and its contralateral homonymous tooth. RESULTS: After orthodontic therapy, all 3 impacted anterior teeth had different degrees of loss of labial alveolar bone height compared with the normal side (central incisor: -1.5 mm, P <0.005; lateral incisor: -1.06 mm, P <0.01; canine: -0.59 mm, P < 0.01). The lateral incisors also showed palatal alveolar bone height loss compared with the unaffected side (-0.8 mm, P <0.005). Alveolar BT at root apices of impacted canines was 1.14 mm thicker than the normal side (P <0.005). Central and lateral incisors were similar to the normal side. The thickness of the alveolar bone at 8, 10, and 12 mm of the impacted canine position was still larger than that on the healthy side, whereas the difference in average thickness between the healthy and affected side had been significantly reduced compared with pretreatment measurements. CONCLUSIONS: There is satisfactory retention of alveolar bone height in canines after orthodontic treatment; however, alveolar bone loss is slightly worse at central and lateral incisors. Retention of alveolar BT was normal for impacted anterior teeth, whereas excess apical alveolar BT at the canines, although still present, was substantially less significant than had been observed before treatment.

Evaluation of two treatment concepts of four implants supporting fixed prosthesis in an atrophic maxilla: finite element analysis.

BACKGROUND: Currently, oblique placement of long implants or the use of short implants to circumvent the maxillary sinus area and provide support for fixed prostheses are viable alternatives. The purpose of this study was to compare these two treatment concepts and ascertain which one exhibits superior biomechanical characteristics. METHODS: Two different treatment concept models were constructed. The first one, LT4I, consisting of two mesial vertical implants positioned in lateral incisor regions and two distal tilted implants (45°) situated in second premolar regions of the maxilla. The second model, VS4I, includes two mesial vertical implants in lateral incisor regions and two vertically positioned short implants in second premolar regions. Numerical simulations were conducted under three loading types: firstly, oblique forces upon the molars; secondly, vertical forces upon the molars; thirdly, oblique forces upon the incisors. The maximum principal stress (σmax) and minimum principal stress (σmin) of the bone, as well as von Mises stress of the implants, were calcuated. RESULTS: Under oblique loading on the molar, higher stress values in the bone were observed in LT4I group. Under vertical loading on molar, higher stress values in the bone were also observed in LT4I group. Furthermore, little difference was found between the two groups under oblique loading on the incisor. CONCLUSION: Both treatment concepts can be applicable for edentulous individuals with moderate atrophic maxilla. Compared to tilted implants, short implants can transmit less occlusal force to the supporting tissues.

Mendelian randomization highlights the causal association of obesity with periodontal diseases.

AIM: The underlying mechanisms connecting obesity and periodontal diseases remain unclear. This study investigates the potential causal association of obesity with periodontal diseases using Mendelian randomization (MR). MATERIALS AND METHODS: Single-nucleotide polymorphisms of obesity traits including body mass index (BMI), waist circumference (WC), and WC adjusted for BMI (WCadjBMI) from large-scale genome-wide association studies were screened for instrumental variables. The single trait periodontitis and the combined trait comprising periodontitis and loose teeth were adopted as surrogates for periodontal diseases. Inverse-variance weighted (IVW), series of sensitivity analyses and multivariable MR were employed to determine the association of obesity with periodontal diseases. RESULTS: IVW results showed that per 1-SD increment in BMI (odds ratio, OR = 1.115; 95% confidence interval [CI] = 1.064-1.169; p < .001) and WC (OR = 1.117; 95% CI = 1.052-1.185; p < .001), but not WCadjBMI, were significantly associated with an increased risk of periodontitis/loose teeth. Moreover, the MR estimates were consistent across other MR sensitivity analyses and multivariable MR. However, a causal association of obesity with the single trait periodontitis was not identified. CONCLUSIONS: The presented evidence supports previous epidemiological findings by showing a potential causal association of genetic liability to obesity with periodontal diseases. The biological mechanisms underlying this association warrant further investigation.

The relationship between local alveolar bone housing and size of canine in maxillary canine-lateral incisor transposition: A retrospective cone-beam computed tomography-based study.

INTRODUCTION: This study aimed to use 3-dimensional data to analyze the relationship between local alveolar bone housing and canine size in maxillary canine-lateral incisor transposition. METHODS: Cone-beam computed tomography study data from 31 patients with maxillary canine-lateral incisor transposition were imported into Dolphin Imaging software (version 11.8; Dolphin Imaging and Management Solutions, Chatsworth, Calif) for measurement. The buccal and palatal alveolar thickness of lateral incisor roots at different heights, the maximal thickness of displaced canine, and canine height were measured. Alveolar height-thickness variation curves at the lateral incisor region and maximal thickness of displaced canine were plotted to calculate the appropriate theoretical minimum alveolar heights of total alveolar housing, buccal alveolar housing after concentrating the bone buccally (TMAH-B1), and original buccal alveolar housing (TMAH-B2) required for correcting the transposition of 2 teeth. RESULTS: Canines could only be moved distally above lateral incisors in 5 patients. The mean value of theoretical minimum alveolar heights of total alveolar housing was 14.57 ± 1.75 mm. It was possible to reposition canines distally by concentrating the alveolar bone buccally in the remaining 26 patients. The mean value of TMAH-B1 was 10.86 ± 3.70 mm. Canines could be repositioned distally directly over the buccal aspect of the lateral incisor in 17 patients. The mean value of TMAH-B2 was 9.30 ± 2.35 mm. Canine height was greater than TMAH-B1 in 18 patients; however, only 10 patients were greater than TMAH-B2. CONCLUSIONS: Correction of transposition was difficult in some patients because of the lack of alveolar bone housing. Repositioning was possible when the height of the canine was higher than a certain height. An accurate assessment of the relationship between alveolar housing and tooth size is recommended.

The position and morphology characteristics of multiple impacted anterior teeth in the unilateral maxillary area: A retrospective study based on cone-beam computed tomography.

INTRODUCTION: This study investigated the position and morphologic characteristics of multiple impacted anterior teeth in the unilateral maxillary area. METHODS: Cone-beam computed tomography images of 21 patients (11 males and 10 females; median age 9.42 years [9.08-11.29]) with multiple teeth impacted were collected and imported into Dolphin Imaging software (Dolphin Imaging and Management Solutions, Chatsworth, Calif). The vertical height, crown orientation, twist direction, and root curvature of each impacted tooth were described. The crown length, root length, and root canal width of impacted and homonym teeth were measured. RESULTS: The positions of the impacted lateral incisors are lower than that of the other 2 anterior teeth. Most crowns of impacted central incisors are positioned distally, labial surfaces in mesial torsion, with most roots, bent toward the distal and labial. Crowns of impacted lateral incisors are positioned mesiolabially, with labial surfaces mostly in distal torsion, and most roots bent toward the mesial and labial. Crowns of impacted canines are mostly positioned mesiolabially, with labial surfaces in mesial torsion. The crowns and roots of the impacted central and lateral incisors were shorter than those of the homonym (P <0.05); however, the difference in crown length is clinically negligible, and there was no difference in root canal widths. There was no difference in the comparison of parameters for the canine group. CONCLUSIONS: There are certain rules in the vertical height, crown orientation, twist direction, and root curvature of multiple impacted anterior teeth in the unilateral maxillary area. Root development of impacted central and lateral incisors was restricted.

The differences of root morphology and root length between different types of impacted maxillary central incisors: A retrospective cone-beam computed tomography study.

INTRODUCTION: The purpose of this trial was to use 3-dimensional data to analyze the differences of root morphology and root length between 3 different types of impacted maxillary central incisors. METHODS: Cone-beam computed tomography images of 126 patients with impacted maxillary central incisors were included in this retrospective study. On the basis of the angle of the impacted incisor to the palatal plane, we categorized the tooth as labial inversely impacted, labially positioned, or palatal impacted incisor. In each category, the early and late dental age groups were classified according to the method of Nolla. The total root length of both impacted and homonym teeth, length of the nondilacerated part of the root, length of the dilacerated part of the root, the angle between the crown and root, and root direction, were measured in the sagittal-view sections using Dolphin Imaging software (version 11.9; Dolphin Imaging and Management Solutions, Chatsworth, Calif). RESULTS: Compared with the early dental age groups, the length of the dilacerated portion of the root and rate of dilaceration for inverse labial and labially positioned impactions increases, and crown-root angle decreases (P <0.05). The dilacerated part of the root bent labially, and the root morphology shows an obvious L-shaped curve. The length of the nondilacerated part of the root for palatal impactions is greater(P <0.05). The dilacerated part of the root bends palatally, and the root morphology shows a continuous C-shaped curve. CONCLUSIONS: Obstruction from the alveolar bone will cause different root morphology. Root morphology of labial impactions shows an obvious L-shaped curve; palatal impactions show a continuous C-shaped curve.

Periodontal disease increases the host susceptibility to COVID-19 and its severity: a Mendelian randomization study.

BACKGROUND: Emerging evidence shows that periodontal disease (PD) may increase the risk of Coronavirus disease 2019 (COVID-19) complications. Here, we undertook a two-sample Mendelian randomization (MR) study, and investigated for the first time the possible causal impact of PD on host susceptibility to COVID-19 and its severity. METHODS: Summary statistics of COVID-19 susceptibility and severity were retrieved from the COVID-19 Host Genetics Initiative and used as outcomes. Single nucleotide polymorphisms associated with PD in Genome-wide association study were included as exposure. Inverse-variance weighted (IVW) method was employed as the main approach to analyze the causal relationships between PD and COVID-19. Three additional methods were adopted, allowing the existence of horizontal pleiotropy, including MR-Egger regression, weighted median and weighted mode methods. Comprehensive sensitivity analyses were also conducted for estimating the robustness of the identified associations. RESULTS: The MR estimates showed that PD was significantly associated with significantly higher susceptibility to COVID-19 using IVW (OR = 1.024, P = 0.017, 95% CI 1.004-1.045) and weighted median method (OR = 1.029, P = 0.024, 95% CI 1.003-1.055). Furthermore, it revealed that PD was significantly linked to COVID-19 severity based on the comparison of hospitalization versus population controls (IVW, OR = 1.025, P = 0.039, 95% CI 1.001-1.049; weighted median, OR = 1.030, P = 0.027, 95% CI 1.003-1.058). No such association was observed in the cohort of highly severe cases confirmed versus those not hospitalized due to COVID-19. CONCLUSIONS: We provide evidence on the possible causality of PD accounting for the susceptibility and severity of COVID-19, highlighting the importance of oral/periodontal healthcare for general wellbeing during the pandemic and beyond.

Design, synthesis, and evaluation of mono-carbonyl analogues of curcumin (MCACs) as potential antioxidants against periodontitis.

BACKGROUND AND OBJECTIVE: The application of curcumin is limited by its instability. Mono-carbonyl analogues of curcumin (MCACs) are structurally stable, yet the intermediate bridging ketones in their skeletons account for increased toxicity. This study aimed to synthesize and screen MCACs that exhibit low cytotoxicity and high antioxidant ability, and the effects of MCACs on experimental periodontitis were also investigated. MATERIALS AND METHODS: The cytotoxicity of MCACs on MC3 T3-E1 was determined by MTT assay. The antioxidant capacity was investigated by the cell viability against H2 O2 -induced damage and the level of reactive oxygen species (ROS) and malondialdehyde (MDA). The localization and protein expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) was detected by immunofluorescence and western blot, respectively. In addition, MCAC was intragastrically administrated in rats with ligature-induced experimental periodontitis. The effects were assessed by bone resorption, as well as the immunohistology staining of inflammatory and oxidative stress markers. RESULTS: MCACs with cyclopentanone and containing pyrone showed lower toxicity than natural curcumin were synthesized (1A-10A, 1H-10H), among which, 1A exhibited the most potent cytoprotective effect against H2 O2 -induced damage. Such effects could be explained by the reduced MDA and ROS level, possibly through the nucleus translocation of Nrf2 and the induction of HO-1. Micro-CT results further indicated that 1A significantly reduced bone loss, along with an increased level of Nrf2 and HO-1, and decreased TNF-α and IL-1ß. CONCLUSION: The present study has synthesized a novel antioxidant MCAC 1A with good biosafety and stability. MCAC 1A could serve as a host response modulator with preventive and protective effects on periodontitis.

TAZ contributes to osteogenic differentiation of periodontal ligament cells under tensile stress.

BACKGROUND AND OBJECTIVE: Bone remodeling during orthodontic treatment is achieved by the osteogenesis of human periodontal ligament cells (PDLCs) subjected to mechanical loadings. Transcriptional co-activator with PDZ-binding motif (TAZ) mediates bone remodeling in response to extracellular mechanical signals. This study aims to investigate the role of TAZ in osteogenesis of PDLCs under tensile strain. MATERIALS AND METHODS: A uniaxial cyclic tensile stress (CTS) at 12% elongation and 6 cycles/min (5 s on and 5 s off) was applied to PDLCs. The osteogenic differentiation was determined by the protein and gene expressions of osteogenic markers using qRT-PCR and Western blot, respectively, and further by alkaline phosphatase (ALP) activity and Alizarin Red S staining. The interaction of TAZ with core-binding factor α1 (Cbfα1) was examined by co-immunoprecipitation. The immunofluorescence histochemistry was used to examine the nucleus aggregation of TAZ and the reorganization of actin filaments. Moreover, small interfering RNA-targeting TAZ (TAZsiRNA) was used for TAZ inhibition and Y-27632 was employed for Ras homologue-associated coiled-coil protein kinase (ROCK) signaling blockage. RESULTS: CTS clearly stimulated the nucleus accumulation of TAZ and its interaction with Cbfα1. CTS-induced osteogenesis in PDLCs was significantly abrogated by the infection with TAZsiRNA, as shown by the decreased stained nodules and protein expressions of Cbfα1, collagen type I, osterix, and osteocalcin, along with the inhibition of ß-catenin signaling. Moreover, ROCK inhibition by Y-27632 hindered TAZ nucleus aggregation and its binding with Cbfα1, which subsequently lead to the decreased osteoblastic differentiation of PDLCs. CONCLUSIONS: Taken together, we propose that TAZ nucleus localization and its interaction with Cbfα1 are essential for the CTS-induced osteogenic differentiation in PDLCs. And such TAZ activation by CTS could be mediated by ROCK signaling, indicating the pivot role of ROCK-TAZ pathway for PDLCs differentiation.

Association between palatally displaced maxillary central incisors and lateral incisors: A retrospective cone-beam computed tomographic study.

INTRODUCTION: The objective of this study was to investigate the location, orientation and root development of maxillary lateral incisors in patients with palatally impacted central incisors. Comparison was made between the lateral incisor on the affected side and that on the normally erupted side. METHODS: Cone-beam computed tomographic images from 20 patients (10 boys, 10 girls, mean age (9.01 ± 1.52 years old) with unilateral palatally impacted maxillary central incisors were imported into Dolphin imaging software 11.8 for 3-dimensional reconstruction and reorientation. Software measurement tools were used to measure the root length, crown distance, angle to palatal plane, distance to midline, and angle to midsagittal plane of the maxillary lateral incisors on both the impacted and unaffected sides. RESULTS: The Wilcoxon signed rank test indicated that lateral incisors on the impacted side were more proclined, at a mean angle difference of 29.47° in the sagittal plane (P < 0.001). The mean length of the roots of the lateral incisors was 1.21 mm shorter (P < 0.05) on the affected side compared with the normal side, and the lateral incisor crowns on the impacted side were located at an average of 4.57 mm closer to the palatal plane than on the normally erupted side (P < 0.001). The angle of long axis of the lateral incisors on the affected side had a greater angulation to the midsagittal plane compared with the unaffected side, with a mean difference of 30.27° (P < 0.001). CONCLUSIONS: Maxillary lateral incisors adjacent to palatally impacted maxillary central incisors side had abnormal root development and demonstrated angulation and position change compared with those adjacent to normally erupted central incisors.

Factors affecting treatment duration of labial inversely impacted maxillary central incisors.

INTRODUCTION: A labial inversely impacted maxillary central incisor is a relatively rare occurrence. The crown of the tooth is directed upward, and its palatal aspect is facing labially. This typical orientation can be the result of trauma to the deciduous incisor transmitted to the palatal side of the crown of the permanent incisor. Labial inversely impacted maxillary central incisors are most commonly combined with labial-lingual root dilacerations. The aim of this study was to examine factors that affect the surgical-orthodontic treatment duration of labial inversely impacted maxillary central incisors. METHOD: The records of 35 consecutively treated patients were retrospectively evaluated. Cone-beam computed tomography images were taken before treatment, and factors affecting treatment time, including age, length, crown-root angle, crown height and depth, angle of inversion, rotation to axial plane, and distance and angle to midline, were measured using Dolphin Imaging software (version 11.8; Patterson Supply, St Paul, Minn). Treatment duration was evaluated for each patient, and logistic regression analyses were applied. RESULTS: The 15 boys and 20 girls had a mean age 8.36 ± 1.36 years. The mean orthodontic traction duration was 11.28 ± 3.08 months. Multiple regression analyses indicated that factors resulting in a longer duration were age (ß = 0.779; P = 0.043), crown height (ß = 0.344; P = 0.007), crown-root angle (ß = -0.037; P = 0.018), and tooth length (ß = -0.623; P = 0.038). CONCLUSIONS: Surgical-orthodontic correction of labial inversely impacted maxillary incisors requires an average of 1 year. Assessments of age, crown height, root dilaceration, and length of incisor can help the orthodontist to better predict treatment duration during consultations with patients and parents.

Survival of labial inversely impacted maxillary central incisors: A retrospective cone-beam computed tomography 2-year follow-up.

INTRODUCTION: The aim of this study was to analyze the development and stability of roots and alveolar bone in orthodontically treated labial inversely impacted maxillary central incisors in a long-term follow-up by cone-beam computed tomography. Comparisons were made between the labial inversely impacted maxillary central incisors after treatment and normally erupted mature contralateral incisors. METHODS: The sample consisted of 12 participants, with a mean age of 7.80 ± 0.91 years. Cone-beam computed tomography scanning data at the completion of treatment and the long-term follow-up were available for each participant.The mean length of follow-up was 24.57 ± 4.33 months. Root length, crown height, root canal width, labial/lingual alveolar bone vertical loss, and bone thickness of the impacted and contralateral incisors were measured with the SimPlant Pro program (version 13.0; Materialise Dental, Leuven, Belgium). RESULTS: In the follow-up, the root lengths of both the labial inversely impacted dilacerated maxillary central incisors (10.99 ± 1.96 mm) and the contralateral mature maxillary central incisors (11.65 ± 1.37 mm) were significantly longer than at posttreatment (8.37 ± 1.74 mm and 9.81 ± 1.65 mm, respectively). The root canal widths of the impacted and contralateral incisors were significantly narrower during the follow-up. The size of the angle between the long axis of the crown and apical third of the root decreased significantly. The lingual alveolar bone loss of the impacted incisors was greater than that of the contralateral incisors. The labial bone thickness at the apex of the impacted incisors increased significantly during the follow-up period. CONCLUSIONS: The treated labial inversely impacted maxillary central incisors had continuous and similar growth as did the mature contralateral incisors in the follow-up period. The roots had an increase in length and a change in direction of the apex, with a relatively stable condition of the surrounding alveolar bone. Neither the labial inversely impacted maxillary central incisors nor the contralateral incisors had further alveolar bone loss.

Combined effects of proinflammatory cytokines and intermittent cyclic mechanical strain in inhibiting osteogenicity in human periodontal ligament cells.

Mechanical strain plays an important role in bone formation and resorption during orthodontic tooth movement. The mechanism has not been fully studied, and the process becomes complex with increased amounts of periodontal patients seeking orthodontic care. Our aims were to elucidate the combined effects of proinflammatory cytokines and intermittent cyclic strain (ICS) on the osteogenic capacity of human periodontal ligament cells. Cultured human periodontal ligament cells were exposed to proinflammatory cytokines (interleukin-1ß 5 ng/mL and tumor necrosis factor-α 10 ng/mL) for 1 and 5 days, and ICS (0.5 Hz, 12% elongation) was applied for 4 h per day. The autocrine of inflammatory cytokines was measured by enzyme-linked immunosorbent assay. The expression of osteoblast markers runt-related transcription factor 2 and rabbit collagen type I was determined using real-time polymerase chain reaction and Western blot. The osteogenic capacity was also detected by alkaline phosphatase (ALP) staining, ALP activity, and alizarin red staining. We demonstrated that ICS impaired the osteogenic capacity of human periodontal ligament cells when incubated with proinflammatory cytokines, as evidenced by the low expression of ALP staining, low ALP activity, reduced alizarin red staining, and reduced osteoblast markers. These data, for the first time, suggest that ICS has a negative effect on the inductive inhibition of osteogenicity in human PDL cells mediated by proinflammatory cytokines.

Management of Impacted Maxillary Central Incisor: Modified Nance Arch Application.

This is a case report of a patient who presented to Wenzhou Medical University--Orthodontic Department at 8 years of age with missing right maxillary central incisor. A detailed clinical and radiographic examination was carried out and treatment plan formulated to surgically expose the impacted incisor and use the modified nance arch (MNA) appliance for orthodontic traction of the tooth in line of arch as phase one treatment followed by phase two treatment with fixed appliances.

Orthodontic and orthopaedic treatment for anterior open bite in children.

BACKGROUND: Anterior open bite occurs when there is a lack of vertical overlap of the upper and lower incisors. The aetiology is multifactorial including: oral habits, unfavourable growth patterns, enlarged lymphatic tissue with mouth breathing. Several treatments have been proposed to correct this malocclusion, but interventions are not supported by strong scientific evidence. OBJECTIVES: The aim of this systematic review was to evaluate orthodontic and orthopaedic treatments to correct anterior open bite in children. SEARCH METHODS: The following databases were searched: the Cochrane Oral Health Group's Trials Register (to 14 February 2014); the Cochrane Central Register of Controlled Trials (CENTRAL)(The Cochrane Library 2014, Issue 1); MEDLINE via OVID (1946 to 14 February 2014); EMBASE via OVID (1980 to 14 February 2014); LILACS via BIREME Virtual Health Library (1982 to 14 February 2014); BBO via BIREME Virtual Health Library (1980 to 14 February 2014); and SciELO (1997 to 14 February 2014). We searched for ongoing trials via ClinicalTrials.gov (to 14 February 2014). Chinese journals were handsearched and the bibliographies of papers were retrieved. SELECTION CRITERIA: All randomised or quasi-randomised controlled trials of orthodontic or orthopaedic treatments or both to correct anterior open bite in children. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed the eligibility of all reports identified. Risk ratios (RRs) and corresponding 95% confidence intervals (CIs) were calculated for dichotomous data. The continuous data were expressed as described by the author. MAIN RESULTS: Three randomised controlled trials were included comparing: effects of Frankel's function regulator-4 (FR-4) with lip-seal training versus no treatment; repelling-magnet splints versus bite-blocks; and palatal crib associated with high-pull chincup versus no treatment.The study comparing repelling-magnet splints versus bite-blocks could not be analysed because the authors interrupted the treatment earlier than planned due to side effects in four of ten patients.FR-4 associated with lip-seal training (RR = 0.02 (95% CI 0.00 to 0.38)) and removable palatal crib associated with high-pull chincup (RR = 0.23 (95% CI 0.11 to 0.48)) were able to correct anterior open bite.No study described: randomisation process, sample size calculation, there was not blinding in the cephalometric analysis and the two studies evaluated two interventions at the same time. These results should be therefore viewed with caution. AUTHORS' CONCLUSIONS: There is weak evidence that the interventions FR-4 with lip-seal training and palatal crib associated with high-pull chincup are able to correct anterior open bite. Given that the trials included have potential bias, these results must be viewed with caution. Recommendations for clinical practice cannot be made based only on the results of these trials. More randomised controlled trials are needed to elucidate the interventions for treating anterior open bite.

Root morphology and development of labial inversely impacted maxillary central incisors in the mixed dentition: a retrospective cone-beam computed tomography study.

INTRODUCTION: The aim of this study was to analyze 3-dimensional data of root morphology and development in labial inversely impacted maxillary central incisors. METHODS: Cone-beam computed tomography images from 41 patients with impacted incisors were divided into early and late dental age groups according to their dental age. Sagittal slices in which the labiolingual width of the tooth was the widest in the axial view were evaluated. The inverse angle, the dilaceration angle, and the length of both impacted and homonym teeth were evaluated with SimPlant Pro software (version 13.0; Materialise Dental NV, Leuven, Belgium). RESULTS: The Student t test indicated that the lengths of the impacted teeth were significantly shorter than those of the homonym teeth (P <0.05), and the root lengths of the early dental age group were significantly shorter than those of the late dental age group. The results from chi-square tests indicated that the incidence of dilacerations was significantly higher in the late dental age group when compared with the early dental age group. Multiple regression analyses indicated that the independent variables for root length of the impacted teeth were dental age (ß = 0.958; P <0.001) and length of the nondilacerated part of the root (ß = 0.435; P <0.001). CONCLUSIONS: Dilaceration was more common in the late dental age group. The roots of labial inversely impacted maxillary central incisors continue developing, but their potential is limited.