Accidental ingestion of a fractured piece of orthodontic aligner: a case report.

BACKGROUND: Ingestion and aspiration of orthodontic devices are rare occurrences, typically associated with components such as expansion keys, archwire segments, dislodged fixed appliances (including brackets, buccal tubes, and bands), as well as fractured metal or plastic appliances. This article describes the clinical diagnosis and treatment process of a case of accidental ingestion of a fractured piece of orthodontic aligner. CASE PRESENTATION: A 31-year-old female under orthodontic treatment by aligners accidentally ingested a fractured piece of the aligner. The special difficulty of this case is that the transparent orthodontic aligner has a low radiopacity. At the beginning, no foreign body was found in the commonly used soft tissue window, causing difficulty in its location until greyscale was adjusted to lung window. The 2-centimeter fractured piece was taken out under anesthesia and endoscopic surgery. CONCLUSION: Materials with low radiopacity should be read with a lower grayscale range. Fractured orthodontic appliances with low retention force should not continue to be worn until consultation with attending doctor.

Mechanical Tension-Stress in Alveolar Cleft Repaired With Autogenous Bone in Canine Models.

OBJECTIVE: Cleft lip and/or palate is a common birth defect worldwide, always accompanied by alveolar cleft. However, the success rate of secondary alveolar bone grafting is unsatisfactory. Rapid maxillary expansion (RME) often used after bone transplantation provides functional stimulation for bone graft area. This study aimed to investigate the effect of RME force on the bone graft area and midpalatal suture, and screen out the most suitable loaded force and loaded teeth, so as to provide a reference for clinical treatment. METHODS: Fourteen 24-week-old male beagles were assigned randomly to 3 groups: blank control, autogenous, and autogenous with RME. Three-dimensional finite element analysis was conducted to evaluate the distribution and value of the stress in the model. The maxillae were collected and subjected to radiography and helical computed tomography to evaluate new bone formation in the graft area. Van Gieson's Picrofuchsin staining was performed for histomorphological observation. RESULTS: After 8 weeks of RME treatment, new bone formation of the dogs was markedly accelerated, and bone resorption was significantly reduced compared with the untreated dogs or those only treated with autogenous iliac bone. The treatment with RME evidently made the bone trabecula more abundant and the area of bone formation larger. Three-dimensional finite element analysis showed that the clinical effect can be achieved by using canine teeth as the loaded teeth and applying force of 10 MPa. CONCLUSION: Rapid maxillary expansion after bone grafting had a positive effect on osteogenesis in a canine model of alveolar cleft.

Induced ankylosis of primary canines for absolute anchorage in the treatment of a patient with Class III malocclusion and cleft soft palate.

This case report describes the induced ankylosis of the primary canines for use as absolute anchorage for maxillary protraction. The patient was a young boy with Class III malocclusion and cleft soft palate. The final occlusion was esthetic, functional, healthy, and stable 4 years after treatment.

Myricetin Prevents Alveolar Bone Loss in an Experimental Ovariectomized Mouse Model of Periodontitis.

Periodontitis is a common chronic inflammatory disease, which leads to alveolar bone resorption. Healthy and functional alveolar bone, which can support the teeth and enable their movement, is very important for orthodontic treatment. Myricetin inhibited osteoclastogenesis by suppressing the expression of some genes, signaling pathways, and cytokines. This study aimed to investigate the effects of myricetin on alveolar bone loss in an ovariectomized (OVX) mouse model of periodontitis as well as in vitro osteoclast formation and bone resorption. Twenty-four healthy eight-week-old C57BL/J6 female mice were assigned randomly to four groups: phosphate-buffered saline (PBS) control (sham) OVX + ligature + PBS (vehicle), and OVX + ligature + low or high (2 or 5 mg∙kg(-1)∙day(-1), respectively) doses of myricetin. Myricetin or PBS was injected intraperitoneally (i.p.) every other day for 30 days. The maxillae were collected and subjected to further examination, including micro-computed tomography (micro-CT), hematoxylin and eosin (H&E) staining, and tartrate-resistant acid phosphatase (TRAP) staining; a resorption pit assay was also performed in vitro to evaluate the effects of myricetin on receptor activator of nuclear factor κ-B ligand (RANKL)-induced osteoclastogenesis. Myricetin, at both high and low doses, prevented alveolar bone resorption and increased alveolar crest height in the mouse model and inhibited osteoclast formation and bone resorption in vitro. However, myricetin was more effective at high dose than at low dose. Our study demonstrated that myricetin had a positive effect on alveolar bone resorption in an OVX mouse model of periodontitis and, therefore, may be a potential agent for the treatment of periodontitis and osteoporosis.

[A study on effects of unilateral maxillary canine impaction on the dento-maxillofacial three-dimensional structure].

PURPOSE: To investigate the three-dimensional structure characteristics of unilateral impacted teeth by cone-beam CT (CBCT), and to evaluate the risk factors for upper impacted teeth, so as to provide evidence for early clinical intervention in orthodontics. METHODS: Thirty patients with unilateral maxillary canine impaction were included. Their CBCT images were measured by three-dimensional reconstruction of Romexis software. The differences of the three-dimensional structure characteristics between two sides were measured and compared with SPSS17.0 software package. Paired t test and regression analysis of related data were performed. RESULTS: Significant difference in inclination of both canine and lateral incisor was found between impacted side and normal eruption side, with canine mesially inclined and lateral incisor distally inclined (P<0.001). Volumes of the canines were significantly bigger and those of the lateral incisor were significantly smaller on the impacted side compared with the normal eruption side (P<0.05). The occurrence of impacted canine increased with the increase of the volume of the canine and decrease of the volume of the lateral incisor. Significant difference in arch length and arch width in canine and premolar area was found between impacted side and normal eruption side (P<0.001). There was no significant difference in width in molar area between both sides(P>0.05). There was no significant difference in arch length in canine, premolar and molar region (P>0.05). CONCLUSIONS: Maxillary impacted canines can lead to three-dimensional abnormalities of the ipsilateral teeth and alveolar bone, the severity of maxillary impacted canine is closely related to surrounding dental structural abnormalities, suggesting that maxillary impacted canines can be predicted, early diagnosed, and early effectively intervened as well.

Rapid maxillary expansion in alveolar cleft repaired with a tissue-engineered bone in a canine model.

This study aims to investigate the effects of orthodontic expansion on graft area of a tissue-engineered bone (TEB) BMSCs/ß-TCP, and to find an alternative strategy for the therapy of alveolar cleft. A unilateral alveolar cleft canine model was established and then treated with BMSCs/ß-TCP under rapid maxillary expansion (RME). Sequential fluorescent labeling, radiography and helical computed tomography were used to evaluate new bone formation and mineralization in the graft area. Hematoxylin-eosin staining and Van Gieson׳s picro fuchsin staining were performed for histological and histomorphometric observation. ALP activity, mineralization and the expression of osteogenic differentiation related genes of BMSCs that grew on the ß-TCP scaffold were promoted by their cultivation in osteogenic medium. Based on fact, TEB was constructed. After 8 weeks of treatment with BMSCs/ß-TCP followed by RME, new bone formation and mineralization of the dogs were markedly accelerated, and bone resorption was significantly reduced, compared with the untreated dogs, or those only treated with autogenous iliac bone. The treatment with both TEB and RME evidently made the bone trabecula more abundant and the area of bone formation larger. What is more, there were no significant differences between BMSCs/ß-TCP group and the group treated with autogenous bone and RME. This study further revealed that TEB was not only a feasible clinical approach for patients with alveolar cleft, but also a potential substituent of autogenous bone, and its combination with RME might be an alternative strategy for the therapy of alveolar cleft.

[Improvement of the determination method of benzene, toluene, ethylbenzene and xylene(BTEX) in water using activated carbon fiber solid-phase microextraction/gas chromatography-mass spectrometry(GC-MS)].

The methods of direct injection, carbon disulfide extraction and activated carbon fiber solid-phase microextraction/GC-MS, usually used in the determination of BTEX in water matrix, are compared and discussed. Experimental data of linearity, precision and limit of detection illustrate that the last one is better than the two other methods. This method was tested by the practical sample experiments and expected to be a simple and sensitive new method for the analysis of BTEX in water.