The mechanism underlying the remodeling effect of lactoferrin on midpalatal sutures during maxillary expansion and relapse in rats.

INTRODUCTION: The remodeling effects of intragastric administration and intramaxillary injection of lactoferrin (LF) on midpalatal sutures (MPS) during maxillary expansion and relapse in rats were studied to explore the underlying bone remodeling mechanism. METHODS: Using a rat model of maxillary expansion and relapse, rats were treated with LF by intragastric administration (1 g·kg-1·d-1) or intramaxillary injection (5 mg·25 µl-1·d-1). The effects of LF on the osteogenic and osteoclast activities of MPS were observed by microcomputed tomography, histologic staining, and immunohistochemical staining, and the expressions of key factors in the extracellular regulated protein kinase 1/2 (ERK1/2) pathway and osteoprotegerin (OPG)-receptor activator of nuclear factor-KB ligand (RANKL)-receptor activator of nuclear factor-KB (RANK) axis were detected. RESULTS: Compared with the group with maxillary expansion alone, osteogenic activity was relatively enhanced, whereas osteoclast activity was relatively weakened in the groups administered LF, and the phosphorylated-ERK1/2: ERK1/2 and OPG: RANKL expression ratios increased significantly. The difference was more significant in the group administered LF intramaxillary. CONCLUSIONS: Administration of LF promoted osteogenic activity at MPS and inhibited osteoclast activity during maxillary expansion and relapse in rats, which may have occurred through regulation of the ERK1/2 pathway and the OPG-RANKL-RANK axis. The efficiency of intramaxillary LF injection was greater than that of intragastric LF administration.

Anti-Caries Effect of Arginine-Containing Formulations in vivo: A Systematic Review and Meta-Analysis.

OBJECTIVE: To assess the anti-caries effect of arginine-containing formulations in vivo on caries lesions compared with fluorides or placebo. METHODS: Randomized or quasi-randomized human clinical trials wherein arginine was delivered by any method were considered. The MEDLINE, Web of Science, EMBASE, Cochrane Library, and CBM databases were searched to identify relevant articles published up to December 2014. Grey literature was also searched. Two authors performed data extraction independently and in duplicate using data collection forms. Each included study was assessed using the Cochrane risk of bias assessment tool. RESULTS: Of the 470 studies screened, 31 full articles were scrutinized and assessed for eligibility. Ten studies (n = 15,546 participants) were selected for final inclusion. The meta-analysis results (n = 7 studies) demonstrated a synergistic effect of arginine when used in conjunction with fluoride on early coronal and root caries compared with placebo or fluoride alone. No specific side effects related to arginine usage were identified. CONCLUSIONS: When used in combination with a calcium compound and fluoride, arginine potentially provides a superior anti-caries effect compared with matched formulations of fluoride alone. However, the level of evidence was downgraded because of risks of bias and potential publication bias. In the future, more high quality, non-industry-supported clinical studies in this research area are required before any definitive recommendations can be made.

Three-dimensional analysis of hard and soft tissue changes in skeletal class II patients with high mandibular plane angle undergoing surgery.

This study aimed to study 3-dimensional (3D) changes of hard and soft tissues of skeletal class II patients after 2-jaw surgery and genioplasty. 32 adult patients diagnosed with mandibular hypoplasia who underwent 2-jaw surgery of maxillary impaction, mandibular advancement and genioplasty were enrolled. Cone-beam computed tomography and 3D stereophotogrammetry was conducted 1 week before and 6 months after surgery. Dolphin imaging software was used to establish a 3D digitizing model and 3D measurement system. Paired t-test was performed to compare the values before and after surgery. Pearson's correlation test assessed the degree of correlations between hard and soft tissue change. The mean impaction of the maxilla was 2.600 ± 3.088 mm at A. The mean advancement of the mandible was 7.806 ± 2.647 mm at B. There was a significant upward and forward movement for most landmarks of the nose and lip, while a significant decrease in nasal tip height (lateral view), upper lip height, and upper and lower vermilion height. The nose's width was significantly increased. For maxillary, Sn, Ac-r, Ac-l, and Ls demonstrated a significant correlation with A and U1 in the anteroposterior axis. However, there were no significant correlations among them in the vertical axis. For mandibular, Li demonstrated a significant correlation with L1 in the anteroposterior axis specifically for the mandible. Notably, correlations between the landmarks of the chin's hard and soft tissues were observed across all axes. The utilization of 3-D analysis facilitated a quantitative comprehension of both hard and soft tissues, thereby furnishing valuable insights for the strategic formulation of orthognathic treatment plans targeting patients with skeletal class II conditions.

Effect of parathyroid hormone on experimental tooth movement in rats.

INTRODUCTION: The aim of this study was to investigate the effect of parathyroid hormone injection on experimental tooth movement in rats. METHODS: Sixty male Wistar rats were randomly divided into 2 groups. Their maxillary right first molars were moved mesially with nickel-titanium closed-coil springs. The experimental group received daily subcutaneous injections of parathyroid hormone at a dose of 4 µg per 100 g of body weight for 12 days, and the control group received vehicle injections. The results were evaluated by intraoral measurements and by hematoxylin and eosin, tartrate-resistant acid phosphatase, and immunohistochemistry staining. RESULTS: The tooth movement and osteoclast numbers were significantly increased in the parathyroid hormone group compared with the control group. The expressions of receptor activator of nuclear factor kappa B ligand and insulin-like growth factor-I were significantly stimulated in the parathyroid hormone group. CONCLUSIONS: The data suggest that short-term parathyroid hormone injection might be a potential method for accelerating orthodontic tooth movement by increasing the alveolar bone turnover rate.

Alveolar bone height changes in the anterior tooth region before and after orthodontic treatment for Angle's Class II division 1 malocclusion and related factors.

BACKGROUND: The aim of this study was to observe the alveolar bone height changes in the anterior tooth region after orthodontic treatment for Angle's Class II division 1 malocclusion. METHODS: Ninety-three patients treated from January 2015 to December 2019 were retrospectively analyzed, of whom 48 received tooth extraction and 45 did not. RESULTS: After orthodontic treatment, the alveolar bone heights in the anterior tooth regions of tooth extraction and non-extraction groups decreased by 67.31% and 66.94%, respectively. Except for the maxillary and mandibular canines in the tooth extraction group as well as the labial side of maxillary anterior teeth and the palatal side of maxillary central incisors of the non-extraction group, the alveolar bone heights of other sites significantly reduced (P<0.05). The reduction in the alveolar bone height of the tooth extraction group significantly exceeded that of the non-extraction group on the palatal side of maxillary incisors and the lingual side of mandibular anterior teeth (P<0.05). CONCLUSIONS: Alveolar bone height in the anterior tooth region decreases after orthodontic treatment for Angle's Class II division 1 malocclusion, being closely related to tooth position together with movement direction and amplitude.

Orthodontic-surgical treatment for severe skeletal class II malocclusion with vertical maxillary excess and four premolars extraction: A case report.

BACKGROUND: Patient satisfaction with facial appearance at the end of orthodontic camouflage treatment is very important, especially for skeletal malocclusion. This case report highlights the importance of the treatment plan for a patient initially treated with four-premolar-extraction camouflage, despite indications for orthognathic surgery. CASE SUMMARY: A 23-year-old male sought treatment complaining about his unsatisfactory facial appearance. His maxillary first premolars and mandibular second premolars had been extracted, and a fixed appliance had been used to retract his anterior teeth for two years without improvement. He had a convex profile, a gummy smile, lip incompetence, inadequate maxillary incisor inclination, and almost a class I molar relationship. Cephalometric analysis showed severe skeletal class II malocclusion (A point-nasion-B point = 11.5°) with a retrognathic mandible (sella-nasion-B point = 75.9°), a protruded maxilla (sella-nasion-A point = 87.4°), and vertical maxillary excess (upper incisor to palatal plane = 33.2 mm). The excessive lingual inclination of the maxillary incisors (upper incisor to nasion-A point line = -5.5°) was due to previous treatment attempts to compensate for the skeletal class II malocclusion. The patient was successfully retreated with decompensating orthodontic treatment combined with orthognathic surgery. The maxillary incisors were repositioned and proclined in the alveolar bone, the overjet was increased, and a space was created for orthognathic surgery, including maxillary impaction, anterior maxillary back-setting, and bilateral sagittal split ramus osteotomy to correct his skeletal anteroposterior discrepancy. Gingival display was reduced, and lip competence was restored. In addition, the results remained stable after 2 years. The patient was satisfied with his new profile as well as with the functional malocclusion at the end of treatment. CONCLUSION: This case report provides orthodontists a good example of how to treat an adult with severe skeletal class II malocclusion with vertical maxillary excess after an unsatisfactory orthodontic camouflage treatment. Orthodontic and orthognathic treatment can significantly correct a patient's facial appearance.

Orthodontic-surgical treatment of an Angle Class II malocclusion patient with mandibular hypoplasia and missing maxillary first molars: A case report.

BACKGROUND: Adult patients presenting with Angle Class II division 1 malocclusions that have a strong skeletal etiology can be challenging for clinicians, particularly if accompanied by retrognathia of the mandible and a dolichofacial growth pattern. CASE SUMMARY: In this case report, we describe the successful orthodontic and surgical management of a 20-year-old woman with an Angle Class II malocclusion with a severe anteroposterior skeletal discrepancy characterized by mandibular deficiency. She had incompetent lips, dental and skeletal Class II malocclusion, high mandibular plane angle, mild mandibular crowding, and two missing maxillary first molars. The treatment plan comprised: (1) Extraction of two mandibular second premolars to decompensate and retract mandibular incisors; (2) pre-surgical alignment, leveling, and space closure of the teeth in both arches, and protraction of the second maxillary molars to close the maxillary space; (3) surgical treatment including a LeFort I osteotomy for maxillary retraction and rotation, a bilateral sagittal split osteotomy for mandibular advancement and rotation, and a genioplasty for correctting the skeletal deformities; and (4) post-surgical correction of the malocclusion. CONCLUSION: The patient's facial esthetics was significantly improved and a desirable occlusion was achieved after 16 mo treatment. Follow-up records after 2 years showed stable esthetics and function.

Multi-disciplinary treatment of maxillofacial skeletal deformities by orthognathic surgery combined with periodontal phenotype modification: A case report.

BACKGROUND: Maxillofacial deformities are skeletal discrepancies that cause occlusal, functional, and esthetic problems, and are managed by multi-disciplinary treatment, including careful orthodontic, surgical, and periodontal evaluations. However, thin periodontal phenotype is often overlooked although it affects the therapeutic outcome. Gingival augmentation and periodontal accelerated osteogenic orthodontics (PAOO) can effectively modify the periodontal phenotype and improve treatment outcome. We describe the multi-disciplinary approaches used to manage a case of skeletal Class III malocclusion and facial asymmetry, with thin periodontal phenotype limiting the correction of deformity. CASE SUMMARY: A patient with facial asymmetry and weakness in chewing had been treated with orthodontic camouflage, but the treatment outcome was not satisfactory. After examination, gingiva augmentation and PAOO were performed to increase the volume of both the gingiva and the alveolar bone to allow further tooth movement. After orthodontic decompensation, double-jaw surgery was performed to reposition the maxilla-mandibular complex. Finally, implant placement and chin molding were performed to restore the dentition and to improve the skeletal profile. The appearance and function were significantly improved, and the periodontal tissue remained healthy and stable. CONCLUSION: In patients with dentofacial deformities and a thin periodontal phenotype, multi-disciplinary treatment that includes PAOO could be effective, and could improve both the quality and safety of orthodontic-orthognathic therapy.

Human Periodontal Ligament Stem Cells Transplanted with Nanohydroxyapatite/Chitosan/Gelatin 3D Porous Scaffolds Promote Jaw Bone Regeneration in Swine.

Dental-tissue-derived stem cells have been used for tissue engineering owing to their ease of isolation and efficacy in in vitro and in vivo proliferation and differentiation. Nanohydroxyapatite/chitosan/gelatin (nHA/CG) three-dimensional porous scaffolds are promising for bone tissue engineering, especially jaw bone regeneration, because of their structural and functional similarity to natural bone. In our previous study, the efficiency of scaffolds with stem cell complexes in osteogenesis was confirmed in vivo in immunocompromised mice. However, studies on the bone regeneration efficiency of stem cell-seeded nHA/CG scaffolds using large animal jaw bone defect models have not been conducted. This study evaluated the bone regeneration potential of the nHA/CG scaffolds with transplanted human periodontal ligament stem cells (hPDLSCs) in critical-sized jaw bone defects in minipigs. The hPDLSCs isolated from periodontal ligaments of discarded teeth (postorthodontic purposes) were seeded onto the nHA/CG scaffolds. The scaffold was successfully synthesized according to our previous studies. Forty-eight critical-sized jaw bone defects were created in 12 minipigs. The defects were randomly assigned to one of three groups [scaffolds with seeded hPDLSCs (hPDLSCs/nHA/CG), only scaffold (nHA/CG), and a negative control group, ie, no cells and scaffolds implanted into defects] to investigate jaw bone regeneration. The bone regeneration capacities of the three groups were assessed for up to 12 weeks. The results showed that the hPDLSCs adhered well to the nHA/CG scaffold in vitro, and the cell-nHA/CG composites significantly increased new bone formation and generated large bones with normal architectures and vascularization in vivo compared to the nHA/CG and control groups. Immunohistochemistry staining showed that runt-related transcription factor 2 (Runx2) was highly expressed in the bone marrow formed in the hPDLSCs/nHA/CG group. This study provides strong evidence for future clinical applications of the nHA/CG scaffolds transplanted with hPDLSCs to regenerate the bone in large jaw bone defects.

Meta-analysis dataset comparing orthodontic mini-implants and conventional anchorage reinforcement for maximum orthodontic anchorage.

The present article describes data from systematic review and meta-analysis investigating the efficacy and safety outcomes comparing mini-implants (MIs) and conventional anchorage reinforcement in patients with maximum dentoalveolar protrusion. All relevant RCTs and non-RCTs published up to 2018 were collected from PubMed, Embase and Cochrane database. Thirteen studies assessing the effect of mini-implants were included, of which 4 were randomized controlled trials (RCTs) and 9 observational studies. The efficacy parameters include mesiodistal movements of molars and incisors and vertical movements of molars and incisors. Whereas, the safety parameters were angular and linear measurement of soft tissue change. Subgroup analysis data was provided in terms of patients average age (<18 years and ≥18 years) at the initiation of treatment. This dataset is suitable for research purpose in the field of orthodontics and also helps dental doctors to determine their treatment preferences in the choice of anchorage reinforcement.

Interfacial structure and melting temperature of alcohol and alkane molecules in contact with polystyrene films.

Infrared-visible sum-frequency-generation spectroscopy (SFG) is used to investigate the interfacial structure of hexadecanol (C16H33OH) and heneicosane (C21H44) in contact with polystyrene films (PS) spin coated on a sapphire substrate. The interfacial structure of hexadecanol is very different from heneicosane in contact with PS. In the crystalline state, the hexadecanol molecules are oriented with the C-C-C axis parallel to the surface plane in contact with PS. For the crystalline heneicosane/PS interface, the SFG spectra are very similar to those observed for molecules oriented with the symmetry axis of the methyl groups parallel to the surface normal. The structure of both hexadecanol (or heneicosane) and the phenyl groups changes sharply at the melting temperature of hexadecanol (or heneicosane). Upon heating the hexadecanol/PS sample above the glass transition temperature (T(g)) of PS, the hexadecanol molecules penetrate through the PS film and adsorb on the sapphire substrate. The adsorbed hexadecanol molecules are oriented with the symmetry axis of the methyl groups parallel to the surface normal. The structure of the PS molecules at the sapphire interface is different because the PS phenyl groups are now in contact with the hydrophobic tails of the hexadecanol molecules, rather than the hydrophilic sapphire substrate. The adsorbed hexadecanol molecules do not disorder at the bulk melting temperature of hexadecanol. In comparison, no adsorption of heneicosane molecules next to sapphire interface upon annealing was observed. The differences between the adsorption of hexadecanol and heneicosane can be explained by the preferential interactions between the hydroxyl groups of the alcohol and hydrophilic sapphire substrate.

Expression of MMP-2 and TIMP-1 during rapid maxillary expansion in rats.

OBJECTIVE: The aim of this study was to investigate the expression of MMP-2 and TIMP-1 during midpalatal suture expansion in rats. DESIGN: 72 male Wistar rats were randomly divided into 2 groups: the experimental group and the control group. In the experimental group, opening loops were applied across the midpalatal suture with an initial force of 50g, whereas in the control group, rats were subjected to sham installation of opening loops without activation. On day 1, 4, 7 and 14, nine rats from each group were sacrificed, and the maxillae were dissected and prepared for Immunohistochemistry (IHC) and RT- PCR examination of MMP-2 and TIMP-1 expression. RESULTS: The results of IHC and Real Time PCR revealed that both protein and mRNA expression of MMP-2 and TIMP-1 were significantly increased after midpalatal expansion, and the ratio of MMP-2/TIMP-1 was also significantly enhanced. CONCLUSIONS: The data suggested that MMP-2 and TIMP-1 might play an important role during the mid-palatal suture remodeling process of maxillary expansion.

A potential therapeutic method for conductive hearing loss in growing children-orthodontic expansion treatment.

Conductive hearing loss, the second most common type of hearing loss, happens when there is a problem transmitting sound waves into inner ear, which will bring a lot of inconvenience to the patient in life and put the impaired person at a competitive disadvantage. Although conductive hearing loss could be relieved by hearing aids, the inconvenience of using these removable aids or the surgery trauma of the implanted ones should not be overlooked. Transversal maxillary deficiency and high palatal arches are often found in patients with conductive hearing loss. Some researchers have reported that there is close relationship between the maxillary contraction and hearing damage. Luckily, rapid maxillary expansion (RME) has been proved to be an effective treatment method for the transversal maxillary deficiency in clinical orthodontics for more than 40 years. Thus, we hypothesized that RME treatment would be a potential therapeutic method for conductive hearing loss in growing children with maxillary constriction.