Evaluation of Postoperative Stability After Open Reduction and Internal Fixation of Zygomaticomaxillary Complex Fractures Using Cone Beam Computed Tomography Analysis.

The aim of this study was to evaluate whether the amount of fracture displacement affects postoperative stability of isolated zygomaticomaxillary complex fractures and to determine whether the 1-point fixation method is as stable as 2- or 3-point fixation methods. The authors investigated 14 patients with 1-point fixation in the zygomaticomaxillary area (group A), 14 patients with 2-point fixation in the zygomaticomaxillary and frontozygomatic area (group B), and 13 patients with 3-point fixation in the zygomaticomaxillary, frontozygomatic, and infraorbital rim area (group C). Stability of the reduced zygomaticomaxillary complex was assessed by comparing immediate postoperative cone beam computed tomography images with those obtained at least 3 months later. Preoperatively, the total mean displacement was 3.79 ±â€Š1.36 mm in group A, 3.43 ±â€Š0.89 mm in group B, and 3.86 ±â€Š1.57 mm in group C. The total postoperative orbital and screw changes were 0.91 ±â€Š0.18 and 0.72 ±â€Š0.08 mm, respectively, in group A; 0.92 ±â€Š0.19 and 0.68 ±â€Š0.09 mm, respectively, in group B; and 0.91 ±â€Š0.11 and 0.66 ±â€Š0.10 mm, respectively, in group C. There were no significant relationships between postoperative stability and amount of fracture displacement in any of the 3 groups, or between the 3 groups (P > 0.05). There was little difference in postoperative stability between the 3 groups. Hence, the amount of displacement is not a very important consideration when deciding the fixation method, including the number and location of miniplates applied for fixation.

The involvement of histone methylation in osteoblastic differentiation of human periosteum-derived cells cultured in vitro under hypoxic conditions.

Although oxygen concentrations affect the growth and function of mesenchymal stem cells (MSCs), the impact of hypoxia on osteoblastic differentiation is not understood. Likewise, the effect of hypoxia-induced epigenetic changes on osteoblastic differentiation of MSCs is unknown. The aim of this study was to examine the in vitro hypoxic response of human periosteum-derived cells (hPDCs). Hypoxia resulted in greater proliferation of hPDCs as compared with those cultured in normoxia. Further, hypoxic conditions yielded decreased expression of apoptosis- and senescence-associated genes by hPDCs. Osteoblast phenotypes of hPDCS were suppressed by hypoxia, as suggested by alkaline phosphatase activity, alizarin red-S-positive mineralization, and mRNA expression of osteoblast-related genes. Chromatin immunoprecipitation assays showed an increased presence of H3K27me3, trimethylation of lysine 27 on histone H3, on the promoter region of bone morphogenetic protein-2. In addition, mRNA expression of histone lysine demethylase 6B (KDM6B) by hPDCs was significantly decreased in hypoxic conditions. Our results suggest that an increased level of H3K27me3 on the promoter region of bone morphogenetic protein-2, in combination with downregulation of KDM6B activity, is involved in the suppression of osteogenic phenotypes of hPDCs cultured in hypoxic conditions. Although oxygen tension plays an important role in the viability and maintenance of MSCs in an undifferentiated state, the effect of hypoxia on osteoblastic differentiation of MSCs remains controversial. In addition, evidence regarding the importance of epigenetics in regulating MSCs has been limited. This study was to examine the role hypoxia on osteoblastic differentiation of hPDCs, and we examined whether histone methylation is involved in the observed effect of hypoxia on osteogenic differentiation of hPDCs.

Are Biodegradable Plates Applicable in Endoscope-Assisted Open Reduction and Internal Fixation of Mandibular Subcondyle Fractures?

PURPOSE: To investigate whether biodegradable plates are applicable in endoscope-assisted open reduction and internal fixation (EAORIF) of mandibular subcondyle fractures. MATERIALS AND METHODS: This retrospective case-series study included patients with mandibular subcondyle fractures treated with EAORIF using an unsintered hydroxyapatite particles/poly-l-lactide biodegradable plate system, with at least 6 months of clinical follow-up data available. The outcome variables were fracture healing with postoperative stability and postoperative complications. Other variables included age, gender, fracture site, cause of injury, accompanying mandibular fracture, total follow-up period, fracture classification, extent of displacement, preoperative status of occlusion, preoperative mandibular movements, fixation materials in accompanying mandibular fracture, location and number of fixation plates, periods of intermaxillary fixation/elastic bands, and postoperative mandibular movements. Fracture healing in these patients was assessed by comparing the immediate postoperative cone-beam computed tomography (CBCT) images with those obtained at least 3 months after surgery. RESULTS: A total of 11 patients, 9 male and 2 female, with a mean ± standard deviation age of 35.3 ± 15.9 years, were included. The mean follow-up period was 18.8 ± 7.8 months. Four patients had an accompanying mandibular fracture. Two 4-hole, 2.0-mm biodegradable plates were fixed with 6-mm screws along the posterior border of the mandibular ramus and near the sigmoid notch. Complete bone formation around the fracture lines or fading of the fracture lines, with no change in the position of the fractured segments, was observed on the postoperative CBCT images at 3 months. With the exception of 2 patients, no patient complained of plate palpability, deviation in occlusion, or discomfort during the postoperative follow-up period. CONCLUSIONS: EAORIF using biodegradable plates for mandible subcondylar fractures is a stable and reliable method, with considerable advantages compared with titanium plates.

A novel combination treatment to stimulate bone healing and regeneration under hypoxic conditions: photobiomodulation and melatonin.

Melatonin has anabolic effects on the bone, even under hypoxia, and laser irradiation has been shown to improve osteoblastic differentiation. The aim of this study was to investigate whether laser irradiation and melatonin would have synergistic effects on osteoblastic differentiation and mineralization under hypoxic conditions. MC3T3-E1 cells were exposed to 1% oxygen tension for the hypoxia condition. The cells were divided into four groups: G1-osteoblast differentiation medium only (as the hypoxic condition), G2-treatment with 50 µM melatonin only, G3-laser irradiation (808 nm, 80 mW, GaAlAs diode) only, and G4-treatment with 50 µM melatonin and laser irradiation (808 nm, 80 mW, GaAlAs diode). Immunoblotting showed that osterix expression was markedly increased in the melatonin-treated and laser-irradiated cells at 48 and 72 h. In addition, alkaline phosphatase activity significantly increased and continued to rise throughout the experiment. Alizarin Red staining showed markedly increased mineralized nodules as compared with only melatonin-treated or laser-irradiated cells at day 7, which significantly increased by day 14. Moreover, when melatonin-treated cells were laser-irradiated, the differentiation and mineralization of cells were found to involve p38 MAPK and PRKD1 signaling mechanisms. However, the enhanced effects of laser irradiation with melatonin were markedly inhibited when the cells were treated with luzindole, a selective melatonin receptor antagonist. Therefore, we concluded that laser irradiation could promote the effect of melatonin on the differentiation and mineralization of MC3T3-E1 cells under hypoxic conditions, and that this process is mediated through melatonin 1/2 receptors and PKRD/p38 signaling pathways.

Melatonin promotes osteoblast differentiation and mineralization of MC3T3-E1 cells under hypoxic conditions through activation of PKD/p38 pathways.

Osteoblastic differentiation and bone-forming capacity are known to be suppressed under hypoxic conditions. Melatonin has been shown to influence cell differentiation. A number of in vitro and in vivo studies have suggested that melatonin also has an anabolic effect on bone, by promoting osteoblastic differentiation. However, the precise mechanisms and the signaling pathways involved in this process, particularly under hypoxic conditions, are unknown. This study investigated whether melatonin could promote osteoblastic differentiation and mineralization of preosteoblastic MC3T3-E1 cells under hypoxic conditions. Additionally, we examined the molecular signaling pathways by which melatonin mediates this process. We found that melatonin is capable of promoting differentiation and mineralization of MC3T3-E1 cells cultured under hypoxic conditions. Melatonin upregulated ALP activity and mRNA levels of Alp, Osx, Col1, and Ocn in a time- and concentration-dependent manner. Alizarin red S staining showed that the mineralized matrix in hypoxic MC3T3-E1 cells formed in a manner that was dependent on melatonin concentration. Moreover, melatonin stimulated phosphorylation of p38 Mapk and Prkd1 in these MC3T3-E1 cells. We concluded that melatonin promotes osteoblastic differentiation of MC3T3-E1 cells under hypoxic conditions via the p38 Mapk and Prkd1 signaling pathways.

Addition of recombinant human bone morphogenic protein-2 to the graft materials improves the clinical outcomes of implants placed in grafted maxillary sinus.

Background/purpose: The long-term outcomes of implants placed in grafted sinuses using recombinant human bone morphogenetic protein-2 (rhBMP-2) are unclear. This study aimed to compare 3- and 5-year implant survival rates and marginal bone loss (MBL) during functional loading. Materials and methods: In this retrospective study, we analyzed 63 implants inserted after maxillary sinus floor augmentation (MSFA) in 45 patients between January 2016 and April 2019. The outcome variables were: 1) 3- and 5-year cumulative survival rates of the implants and 2) MBL after functional loading. Other assessed variables included patient demographic information, preoperative residual bone height (RBH), surgical site, implant length and diameter, graft material, healing period before loading, prosthetic type, and opposing dentition. Results: The cumulative 3- and 5-year survival rates of the implants were 100% in the rhBMP-2 group and 95.5% and 86.4% in the non-rhBMP-2 group, respectively. The average 3- and 5-year MBL were 1.14 ± 0.67 mm, 1.30 ± 0.74 mm in the rhBMP-2 group and 1.68 ± 0.90 mm, 2.27 ± 1.29 mm in the non-rhBMP-2 group, respectively. Significant differences were observed between 3 and 5 years between the two groups. Conclusion: Addition of the rhBMP-2 to the graft materials positively affects implant placement in the grafted maxillary sinus in terms of implant survival and MBL when preoperative RBH is unfavorable.

Management of multiple odontogenic keratocysts associated with nevoid basal cell carcinoma syndrome: a case report of 11-year follow-up.

Multiple odontogenic keratocysts (OKC) are a distinguishing feature of nevoid basal cell carcinoma syndrome (NBCCS). Owing to the high recurrence rate of syndromes associated OKCs, complete surgical resection is generally recommended as a definitive treatment. Herein, we report the management of multiple OKCs with marsupialization followed by excision with peripheral ostectomy in an NBCCS patient. We then discuss lesion progression over 11 years of annual follow-ups.

Human Dental Pulp-Derived Mesenchymal Stem Cell Potential to Differentiate into Smooth Muscle-Like Cells In Vitro.

Previous studies have shown that mesenchymal stem cells (MSCs) derived from various tissue sources can be differentiated into smooth muscle-like cells (SMLCs) in vitro. In this paper, dental pulp-derived mesenchymal stem cells (DPSCs) were evaluated for their differentiation ability towards smooth muscle-like cells (SMLCs) under the effect of widely used cytokines (TGF-ß1 and PDGF-BB) with special focus on different culturing environments. For this purpose, both the commercially used culturing plates (Norm-c) and 0.1% gelatin-precoated (Gel-c) plates were used. Isolated cells displayed plastic adherence, pluripotency and cell surface marker profiling, and adipogenic and osteogenic differentiation potential with lineage specific marker expression. Differentiated cells induced under different culturing plates showed successful differentiation into SMLCs by positively expressing smooth muscle cell (SMC) specific markers both at the mRNA and protein levels. Gelatin coating could substantially enhance DPSC differentiation potential than Norm-c-induced cells. However, the absence of mature marker MHY-11 by immunostaining results from all treatment groups further indicated the development of immature and synthetic SMLCs. Finally, it was concluded that DPSC differentiation ability into SMLCs can be enhanced under cytokine treatment as well as by altering the cellular niche by precoating the culturing plates with suitable substrates. However, to get fully functional, contractile, and mature SMLCs, still many different cytokine cocktail combinations and more suitable coating substrates will be needed.

Clinical outcome of implants placed in grafted maxillary sinus via lateral approach: A 10-year follow-up study.

BACKGROUND/PURPOSE: The maxillary sinus floor augmentation (MSFA) technique is frequently used for the preparation of implant sites in the maxillary region. The aim of this study was to investigate the 10-year outcome of dental implants placed in a grafted maxillary sinus, and identify possible risk factors for implant failure. MATERIALS AND METHODS: We retrospectively analyzed 202 implants after MSFA in 97 patients from January 2008 to April 2009. The outcome variables were 1) 10-year cumulative survival rate of the implant, 2) risk factors for implant failure, and 3) correlation between preoperative residual bone height (RBH) and graft materials in terms of implant survival. Graft materials used were divided into five different groups: autogenic, allogenic, xenogenic, combination of allogenic and xenogenic, or combination of autogenic and xenogenic graft. RESULTS: The cumulative 10-year survival rate for the implants was 96.04%. In regions with a residual bone height of 5.0 mm and less, greater RBH was preferable for long-term implant survival (odds ratio = 3.475; p = 0.035). Implant survival was not significantly different with different graft materials, even when RBH was unfavorable. CONCLUSION: The placement of dental implants with MSFA is a reliable procedure. Further, RBH is an important predictor of long-term implant survival.

Bioabsorbable plates versus metal miniplate systems for use in endoscope-assisted open reduction and internal fixation of mandibular subcondylar fractures.

PURPOSE: To compare bioabsorbable plates with metal miniplate systems for use in endoscope-assisted open reduction and internal fixation (EAORIF) of mandibular subcondylar fractures. MATERIALS AND METHODS: This retrospective cohort study included patients with mandibular subcondylar fractures treated with EAORIF using bioabsorbable unsintered hydroxyapatite/poly l-lactide composite plates or titanium miniplate systems. The outcome variables included preoperative fracture conditions, postoperative stability during fracture healing, and complications during the follow-up period. Other variables included clinical characteristics (age, sex, fracture site, and total follow-up duration) and intra- and postoperative data (surgical duration, duration of intermaxillary fixation/elastic band guidance). Variables were evaluated using descriptive statistics and compared between groups using the Mann-Whitney test and the chi-square test or Fisher's exact test, as appropriate. RESULTS: In total, 28 patients were analyzed, including 13 who underwent EAORIF using bioabsorbable plates and 15 who underwent EAORIF using titanium miniplates. With the exception of second surgery for plate removal, none of the assessed variables showed significant differences between the two groups (p < 0.05). CONCLUSIONS: Our results suggest that EAORIF using biodegradable plates is a stable and reliable method for the management of mandibular subcondylar fractures and eliminates the need for secondary surgery for plate removal.

Analysis of speech and tongue motion in normal and post-glossectomy speaker using cine MRI.

OBJECTIVE: Since the tongue is the oral structure responsible for mastication, pronunciation, and swallowing functions, patients who undergo glossectomy can be affected in various aspects of these functions. The vowel /i/ uses the tongue shape, whereas /u/ uses tongue and lip shapes. The purpose of this study is to investigate the morphological changes of the tongue and the adaptation of pronunciation using cine MRI for speech of patients who undergo glossectomy. MATERIAL AND METHODS: Twenty-three controls (11 males and 12 females) and 13 patients (eight males and five females) volunteered to participate in the experiment. The patients underwent glossectomy surgery for T1 or T2 lateral lingual tumors. The speech tasks "a souk" and "a geese" were spoken by all subjects providing data for the vowels /u/ and /i/. Cine MRI and speech acoustics were recorded and measured to compare the changes in the tongue with vowel acoustics after surgery. 2D measurements were made of the interlip distance, tongue-palate distance, tongue position (anterior-posterior and superior-inferior), tongue height on the left and right sides, and pharynx size. Vowel formants Fl, F2, and F3 were measured. RESULTS: The patients had significantly lower F2/Fl ratios (F=5.911, p=0.018), and lower F3/F1 ratios that approached significance. This was seen primarily in the /u/ data. Patients had flatter tongue shapes than controls with a greater effect seen in /u/ than /i/. CONCLUSION: The patients showed complex adaptation motion in order to preserve the acoustic integrity of the vowels, and the tongue modified cavity size relationships to maintain the value of the formant frequencies.

Epinephrine-induced lactic acidosis in orthognathic surgery: a report of two cases.

Submucosal infiltration and the topical application of epinephrine as a vasoconstrictor produce excellent hemostasis during surgery. The hemodynamic effects of epinephrine have been documented in numerous studies. However, its metabolic effects (especially during surgery) have been seldom recognized clinically. We report two cases of significant metabolic effects (including lactic acidosis and hyperglycemia) as well as hemodynamic effects in healthy patients undergoing orthognathic surgery with general anesthesia. Epinephrine can induce glycolysis and pyruvate generation, which result in lactic acidosis, via ß2-adrenergic receptors. Therefore, careful perioperative observation for changes in plasma lactate and glucose levels along with intensive monitoring of vital signs should be carried out when epinephrine is excessively used as a vasoconstrictor during surgery.

Role of gingival manifestation in diagnosis of granulomatosis with polyangiitis (Wegener's granulomatosis).

PURPOSE: This report describes a case of granulomatosis with polyangiitis (GPA) in which the gingival manifestation was crucial in both making an early diagnosis and possibly in deciding the approach to treatment. METHODS: A 57-year-old sailor presented to the Department of Dentistry at Ulsan University Hospital complaining of gingival swelling since approximately 2 months. He had orofacial granulomatous lesions and the specific gingival manifestation of strawberry gingivitis. RESULTS: The diagnosis of GPA was made on the basis of clinical symptoms and signs, and confirmed by the presence of the anti-neutrophil cytoplasmic antibody and a positive biopsy. The patient was admitted to the hospital and subsequently placed on a disease-modifying therapy regimen that included methotrexate and prednisone. CONCLUSIONS: Identification of the gingival manifestation of the disease permitted an early diagnosis and prompt therapy in a disease in which time is a crucial factor. Because of its rapid progression and potentially fatal outcome, an early diagnosis of GPA is important. Therefore, dentists should be aware of the oral signs and symptoms of such systemic diseases.

Feed enzyme technology: present status and future developments.

Exogenous enzymes are now well accepted as a class of feed additives in diet formulations for poultry and pigs to overcome the negative effects of anti-nutritional factors, and to improve digestion of dietary components and animal performance. An overview of the current status of feed enzyme technology, including the different type of enzymes and modes of action, is provided. Variable response to enzyme supplementation is an important reason limiting the widespread acceptance of feed enzymes. The major reasons contributing to these variable responses are discussed. Main features of the next generation of feed enzymes and the various trends that will drive the future use of enzymes are highlighted. The use of feed enzymes in poultry and pig feed formulations is expected to increase in the future and this will be driven by on-going changes in the world animal production. Aquaculture and ruminant industries are emerging markets for exogenous feed enzymes. The article presents some promising patents on feed enzyme technology.

Analysis of speech and tongue motion in normal and post-glossectomy speaker using cine MRI

ABSTRACT Objective Since the tongue is the oral structure responsible for mastication, pronunciation, and swallowing functions, patients who undergo glossectomy can be affected in various aspects of these functions. The vowel /i/ uses the tongue shape, whereas /u/ uses tongue and lip shapes. The purpose of this study is to investigate the morphological changes of the tongue and the adaptation of pronunciation using cine MRI for speech of patients who undergo glossectomy. Material and Methods Twenty-three controls (11 males and 12 females) and 13 patients (eight males and five females) volunteered to participate in the experiment. The patients underwent glossectomy surgery for T1 or T2 lateral lingual tumors. The speech tasks “a souk” and “a geese” were spoken by all subjects providing data for the vowels /u/ and /i/. Cine MRI and speech acoustics were recorded and measured to compare the changes in the tongue with vowel acoustics after surgery. 2D measurements were made of the interlip distance, tongue-palate distance, tongue position (anterior-posterior and superior-inferior), tongue height on the left and right sides, and pharynx size. Vowel formants Fl, F2, and F3 were measured. Results The patients had significantly lower F2/Fl ratios (F=5.911, p=0.018), and lower F3/F1 ratios that approached significance. This was seen primarily in the /u/ data. Patients had flatter tongue shapes than controls with a greater effect seen in /u/ than /i/. Conclusion The patients showed complex adaptation motion in order to preserve the acoustic integrity of the vowels, and the tongue modified cavity size relationships to maintain the value of the formant frequencies.