Perspective of endodontic sealers based on calcium silicate / 대한치과재료학회지

Calcium silicate based sealers (CSBS) were introduced under the background of a calcium silicate based hydrophilic cement (mineral trioxide aggregate: MTA), composed by tricalcium and dicalcium silicate. Inspired by the excellent sealing ability and biocompatibility of MTA, the sealers establish a biological point of view on the canal obturation. There is no doubt that premixed calcium silicate based sealers has gained wide acceptance in clinical application, but unstable setting time, slight solubility and retreatability of the CSBS might compromise the usage and value of the new class of endodontics sealers. Further clinical studies are required to improve the properties of the calcium silicate based sealers.

Calcium silicate-based root canal sealers: a literature review

Epoxy resin-based sealers are currently widely used, and several studies have considered AH Plus to be the gold-standard sealer. However, it still has limitations, including possible mutagenicity, cytotoxicity, inflammatory response, and hydrophobicity. Drawing upon the advantages of mineral trioxide aggregate, calcium silicate-based sealers were introduced with high levels of biocompatibility and hydrophilicity. Because of the hydrophilic environment in root canals, water resorption and solubility of root canal sealers are important factors contributing to their stability. Sealers displaying lower microleakage and stronger push-out bond strength are also needed to endure the dynamic tooth environment. Although the physical properties of calcium silicate-based sealers meet International Organization for Standardization recommendations, and they have consistently reported to be biocompatible, they have not overcome conventional resin-based sealers in actual practice. Therefore, further studies aiming to improve the physical properties of calcium silicate-based sealers are needed.

Calcium silicate-based root canal sealers: a literature review

Epoxy resin-based sealers are currently widely used, and several studies have considered AH Plus to be the gold-standard sealer. However, it still has limitations, including possible mutagenicity, cytotoxicity, inflammatory response, and hydrophobicity. Drawing upon the advantages of mineral trioxide aggregate, calcium silicate-based sealers were introduced with high levels of biocompatibility and hydrophilicity. Because of the hydrophilic environment in root canals, water resorption and solubility of root canal sealers are important factors contributing to their stability. Sealers displaying lower microleakage and stronger push-out bond strength are also needed to endure the dynamic tooth environment. Although the physical properties of calcium silicate-based sealers meet International Organization for Standardization recommendations, and they have consistently reported to be biocompatible, they have not overcome conventional resin-based sealers in actual practice. Therefore, further studies aiming to improve the physical properties of calcium silicate-based sealers are needed.

Mastoid Obliteration with Silicone Blocks after Canal Wall Down Mastoidectomy

OBJECTIVES: To evaluate the usefulness of silicone blocks as graft material for mastoid cavity obliteration in the prevention of problematic mastoid cavities after canal wall down mastoidectomies. METHODS: Retrospective evaluation of 20 patients who underwent mastoid obliteration with silicone blocks between 2002 and 2009 at the Chonnam National University Hospital. The cases consisted of 17 patients with chronic otitis media with cholesteatoma and 3 patients with adhesive otitis media. The postoperative follow-up period was an average 49 months (range, 6 to 90 months). The surgical technique used at our institution composed four major steps: First, the canal wall down mastoidectomy was performed and the middle ear procedure was completed. The silicone blocks were used to fill up the mastoidectomized cavity. Then, a cortical bone pate was used to cover the surface of the silicone blocks. Finally, temporalis fascia and a split musculoperiosteal flap were used to surround the bone pate for reinforcement of the reconstructed canal wall. We examined postoperative success rate and hearing outcomes. RESULTS: In 19 cases (95%), the reconstructed canal wall maintained a cylindrical shape and the ear drum healed without perforation. In only 1 case (5%), the reconstructed canal wall was destroyed with ear drum perforation. The mean improvement in air-bone gap was about 12 dB (P<0.05), and the mean improvement in air-conduction was about 16 dB (P<0.05). CONCLUSION: We suggest that silicone blocks could be valuable resources as graft materials for mastoid obliteration after canal wall down mastoidectomies.

A comparison of the shaping ability of reciprocating NiTi instruments in simulated curved canals

OBJECTIVES: The study was to compare the shaping ability of Reciproc (VDW) and WaveOne (Dentsply Maillefer) instruments compared with ProTaper, Profile and hand instrument during the preparation of simulated root canals. MATERIALS AND METHODS: Five groups (n = 5) were established. Reciproc, WaveOne, ProTaper, Profile and K file (K-flexo file) were used to prepare the resin simulated canals. A series of preoperative and postoperative images were taken by a microscope and superimposed in 2 different layers. The amount of resin removed from both the inner and the outer sides of the canal was measured to the level of 10 mm from the apical tip, with a 1 mm increment. RESULTS: The mean of resin removal from the inner canal wall was not different from the outer canal wall for Reciproc and WaveOne groups at apical third (1 - 3 mm level). There was no difference in the change of working length and maintenance of canal curvature. NiTi instruments are superior to stainless-steel K file in their shaping ability. CONCLUSIONS: Within the limitation of this present study, Reciproc and WaveOne instruments maintained the original canal curvature in curved canals better than ProTaper and Profile, which tend to transport towards the outer canal wall of the curve in the apical part of the canal.

Delayed Facial Nerve Paralysis after Tympanomastoid Surgery: The Potentiality of Fungal Infection and Treatment / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The purpose of this study was to assess the clinical courses and clinical outcomes of delayed facial nerve paralysis (DFNP) after middle ear and mastoid surgery. SUBJECTS AND METHOD: In our hospital, postoperative DFNP occurred in 13 cases among the patients who underwent ear surgery from December 2000 to February 2010. During the same period, another 4 cases with postoperative DFNP were diagnosed at a local clinic. We assessed the degree of DFNP by using House-Brackmann grade (HBG) and separated 8 patients in grade II, 6 patients in grade III and 3 patients in Grade IV. Among 17 patients, DFNP occurred after open cavity mastoidectomy in 11 cases and after closed cavity mastoidectomy in the rest of 6 cases. RESULTS: Among 17 postoperative DFNP, fungal infections were found in three patients. Patients for whom antifungal agent was relatively delayed in application, their condition did not improved. CONCLUSION: After treatment, most of patients recovered within 1 month and there were no other associated infection during hospitalization. We suggest that antifungal agents should be used as soon as possible when patients complain about DFNP following open cavity mastoidectomy.

Cavernous Hemangioma of the Tympanic Membrane

Cavernous hemangioma seems to most frequently arise in the posterior portion of the external auditory canal. However, they rarely occur in the tympanic membrane. A 49-year-old male patient was referred for evaluation of right-sided pulsatile tinnitus that he'd experienced for the previous 2 years. Temporal bone computerized tomography showed an isolated soft tissue mass just lateral to the tympanic membrane. There was no evidence of bony erosion or middle ear invasion. The patient underwent excision of the mass using a postauricular approach. The mass was removed en bloc and the defect of the tympanic membrane was repaired by tympanoplasty type I. There was no recurrence after 1 year of follow-up.

Transplantation of Neural Differentiated Human Mesenchymal Stem Cells into the Cochlea of an Auditory-neuropathy Guinea Pig Model

The aim of this study was to determine the effects of transplanted neural differentiated human mesenchymal stem cells (hMSCs) in a guinea pig model of auditory neuropathy. In this study, hMSCs were pretreated with a neural-induction protocol and transplanted into the scala tympani of the guinea pig cochlea 7 days after ouabain injury. A control model was made by injection of Hanks balanced salt solution alone into the scala tympani of the guinea pig cochlea 7 days after ouabain injury. We established the auditory neuropathy guinea pig model using 1 mM ouabain application to the round window niche. After application of ouabain to the round window niche, degeneration of most spiral ganglion neurons (SGNs) without the loss of hair cells within the organ of Corti and increasing the auditory brain responses (ABR) threshold were found. After transplantation of neural differentiated hMSCs, the number of SGNs was increased, and some of the SGNs expressed immunoreactivity with human nuclear antibody under confocal laser scanning microscopy. ABR results showed mild hearing recovery after transplantation. Based on an auditory neuropathy animal model, these findings suggest that it may be possible to replace degenerated SGNs by grafting stem cells into the scala tympani.

Diastema closure with direct composite: architectural gingival contouring / 대한치과보존학회지

One of the most challenging task in closing anterior diastema is avoiding "black triangle" between the teeth. This paper reports a case that the closure of diastema in anterior teeth could be successfully accomplished using direct adhesive restorations and gingival recontouring. The traditional technique using Mylar strip was modified to increase the emergence profile with natural contours at the gingival-tooth interface. Mylar strip was extended out of the sulcus by approximately 1 mm high from the gingival margin, and a small cotton pellet was used to provide the emergence contour. This modified approach is acceptable for the clinical situation.

Effect of Nebulized Bovine Surfactant for Experimental Otitis Media with Effusion

OBJECTIVES: In this study, we evaluated the efficacy of nebulized bovine pulmonary surfactant on experimentally induced otitis media with effusion (OME) in guinea pigs. METHODS: Twenty guinea pigs were divided into three groups. Four untreated animals served as normal controls. Experimental OME was established in both ears of the remaining 16 animals by a transbullar injection of 10 microL of Pseudomonas aeruginosa lipopolysaccharide in saline. Thereafter, the guinea pigs received nebulized phosphate buffered saline (n=8) or nebulized bovine pulmonary surfactant (n=8). Nebulization was given daily for 7 days. On day 8, all the animals' passive opening pressure (POP) of the Eustachian tube was measured and histopathological observations of the bulla were made by light microscopy. RESULTS: Nebulized bovine pulmonary surfactant significantly reduced the POP compared to that of saline nebulization. The bovine pulmonary surfactant improved the tubal patency and produced less histopathologcally-evident edematous bullar mucosa. CONCLUSION: Nebulization of bovine pulmonary surfactant plays an important role in treating otitis media with effusion in guinea pigs. Our results suggest that the chosen nebulized bovine pulmonary surfactant can be of good clinical benefit for treating OME in the future.

Fate of Sudden Deafness Occurring in the Only Hearing Ear: Outcomes and Timing to Consider Cochlear Implantation

The present study was undertaken to learn the outcome of patients with idiopathic sudden sensorineural hearing loss (ISSNHL) in their only hearing ear. Timing to conduct a cochlear implantation was also determined in those who did not recover the hearing. The study group comprised 25 patients who confronted ISSNHL in their only hearing ear. A total of 192 patients, who had ISSNHL in one ear and had normal contralateral ear, served as the control. Demographically there were no significant differences between the groups. The recovery rate was similar between the groups: 64.0% in the experimental and 62.5% in the control group. The duration until the recovery of ISSNHL in the only hearing ear was 5-90 days (average 17.6 days). In the experimental group, 8 patients did not recover from ISSNHL, and underwent cochlear implantation in 6 with satisfactory results. These results suggest that the same treatment is applicable for patients with ISSNHL regardless of whether their contralateral ear is deaf or normal. For those who do not recover from ISSNHL in their only hearing ear, culminating in bilateral deafness, we may consider further definitive treatment including cochlear implantation as early as 3 months after initiating the treatment of ISSNHL.

Comparative Outcome after Treatment for Synchronous vs. Metachronous Colorectal Cancer Liver Metastasis

PURPOSE: This study was designed to compare outcomes in patients who underwent hepatectomy or radiofrequency thermal ablation (RFA) for synchronous or metachronous colorectal liver metastases (CLM). METHODS: One hundred twenty-two patients who underwent hepatectomy or RFA for their first CLM between 2001 and 2004 were enrolled in this study. The patients were divided into two groups (synchronous [N=77] and metachronous [N=45] CLM). Patient characteristics, clinicopathologic features, long-term outcomes, and prognostic factors were analyzed retrospectively. RESULTS: There were no significant differences in the 5-year disease-free and overall survival rates between the synchronous and metachronous CLM groups (36.2% vs. 37.2%, p=0.78; and 53.0% vs. 54.4%, p=0.82, respectively). Patients in the synchronous CLM group underwent more bilobar hepatic resections, intra-operative RFA, or co-modality treatments than the metachronous CLM group (p=0.035). The surgical resection group had a longer disease-free survival, but not overall survival than the RFA group. Greater N stage and female gender were associated with a worse prognosis in overall survival; N0 stage and surgical resection were good prognostic factors for disease-free survival. N stage and surgical resection were also statistically significant prognostic factors based on multivariate analysis. CONCLUSION: The synchronicity of CLM is not a significant prognostic factor, but the clinicopathologic characteristics that reflect more disseminated disease than metachronous metastasis are significant prognostic factors. Tumor characteristics and aggressiveness may be more important for prognosis than chronology.

Mineral trioxied aggregate and its substitutes / 대한치과보존학회지

Since its introduction in 1993, Mineral Trioxide Aggregate (MTA) has been shown to be superior to others in sealing, biocompatibility, and many other aspects of clinical endodontics. MTA is primarily Portland cement with bismuth oxide as a radiopacitifier. Although some studies suggested that the reasonable-priced Portland cement could be used instead of MTA, but MTAs are different from Portland cement in its composition, especially in heavy metal contents. Therefore, clinicians should be meticulous adapting the Portland cement as a MTA substitute.

Expression of Aquaporin-2 in the Inner Ear of Water-Deprived Guinea Pigs / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Although the role of aquaporin-2 (AQP2) in the kidney has been well defined, its role in the inner ear remains to be determined. The present study was to investigate the effect of water deprivation on the expression of AQP2 in the inner ear. MATERIALS AND METHOD: Healthy male guinea pigs weighing 250 g were used. The experimental group underwent water restriction and the control underwent water loading with sucrose-containing water for 3 days. Concentrations of plasma arginine-vasopressin (AVP) were determined and electrocochleography (ECoG) recordings were made. An RT-PCR, real-time PCR and Westernblotting analysis were used for quantitative analysis of AQP2 mRNA and AQP2 protein expression. Immunohistochemistry was also used to evaluate the distribution of AQP2 water channel proteins in the inner ear. RESULTS: AQP2 was mainly expressed in the epithelium of endolymphatic sac, spiral limbus, spiral ligament and stria vascularis of scala media. The concentrations of plasma AVP were 9.2+/- 0.8 pg/mL in the experimental group and 0.78+/-0.3 pg/mL in the control. The summation potential/ action potential (SP/AP) ratio in ECoG was markedly increased in the experimental group (0.55 in the experimental and 0.29 in the control). RT-PCR and real time PCR as well as Western blot analysis showed that the level of AQP2 mRNA and protein in the cochlea and endolymphactic sac of the water-deprived group was significantly higher than those in the control group. CONCLUSION: These data suggest that AQP2 is one of the important water channels in fluid homeostasis in the inner ear. Moreover, the volume of endolymphatic space can be increased via AVP-AQP2 system in response to water deprivation.

A Clinical Review of 1,060 Dizziness Cases Who Visited Patients in Emergency Room / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Dizziness is an illusion of environmental movement due to various causes. It is difficult to confirm the diagnosis of dizziness according to history and physical examination in restricted situation such as emergency room. The aim of this study is to find another clue for diagnosis in patients of dizziness who visited emergency room. SUBJECTS AND METHOD: Author retrospectively reviewed the charts of 1,060 patients of dizziness who visited emergency room at Chonnam University Hospital from July 2004 to June 2005 and accumulated the various information such as final diagnosis, clinical feature, physical examination, present illness and past history etc. RESULTS: Average age of patients was 57. The most frequently consulted department for evaluation of dizziness was the department of otolaryngology, head and neck surgery (> 29.8%). Benign paroxysmal positional vertigo (BPPV) was the most frequent final diagnosis (14.4%) in all patients. But, cerebrovascular disease was the more frequent cause for dizziness in male and old age group. Whirling type dizziness was frequent in BPPV (36.8%) and spontaneous nystagmus was detected frequently in peripheral type vertigo such as vestibular neuritis (65.1%). Average age of central vertigo patients was 61.4 and other vertigo patients was 55. Patients of central vertigo visited the emergency room more frequently in the months of Dec, Jan, Feb and patient of other vertigo visited more frequently in June, July, Aug. CONCLUSION: Various specialized departments should be involved in effective and exact diagnosis of dizziness. The organized questionnaire in addition to prevalence, incidence and characteristics of dizziness may be used in finding another clue for diagnosis and managing dizzy patients helpfully.

A bioactivity study of Portland cement mixed with beta-glycerophosphosphate on human pulp cell / 대한치과보존학회지

The purpose of this study is to investigate the response of human pulp cell on Portland cement mixed with beta-glycerophosphate. To investigate the effect of beta-glycerophosphate and/or dexamethasone on human pulp cell, ALP activity on various concentration of beta-glycerophosphate and dexamethasone was measured and mineral nodule of human pulp cell was stained with Alizarin red S. MTS assay and ALP activity of human pulp cell on Portland cement mixed with various concentration of beta-glycerophosphate (10 mM, 100mM, 1M) was measured and the specimens were examined under SEM. Addition of beta-glycerophosphate or dexamethasone alone had no effect however, the addition of 5 mM beta-glycerophosphate and 100 nM dexamethasone had the largest increasement in ALP activity. There was no toxicity in all samples and the data showed that Portland cement mixed with 10 mM beta-glycerophosphate had more increase in ALP activity compared with control. In conclusion, Portland cement mixed with beta-glycerophosphate has no toxicity and promotes differentiation and mineralization of pulp cell compared with additive-free Portland cement. This implicated that application of Portland cement mixed with beta-glycerophosphate might form more reparative dentin and in turn it would bring direct pulp capping to success.

Cholesterol Granuloma of the Tympanic Membrane Presenting as a Blue Eardrum

Intramembranous tympanic membrane cholesterol granuloma (CG) occurs infrequently. Here, the authors report a case of CG in the tympanic membrane presenting as a blue eardrum in the right ear. In addition, a pinhole perforation noted in the anterosuperior area revealed a brown discharge. High-resolution temporal bone CT showed a bulging mass shadow in the middle ear and a soft tissue dense lesion that filled both the epitympanum and mastoid cavity. Tympanomastoidectomy was performed under general anesthesia. New bone formation was confirmed in the mastoid antrum and epitympanum, and the epitympanum was blocked by new bone. The tympanic membrane revealed a round, brownish mass with a glistening surface and a severely thickened pars tensa. We herein report this case and review pertinent medical literature.

Effect of Platelet Rich Plasma on Facial Nerve Regeneration in Acute Nerve Injury Model / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The object of this study was to evaluate the effect of platelet rich plasma (PRP) on facial nerve regeneration from an axotomy injury in the guinea pig model. MATERIALS AND METHOD: Experiments involved the transection and repair of right facial nerve. The right facial nerve of 14 albino guinea pigs were completely transected and immediately sutured, followed by fibrin glue only (control group) or fibrin glue +PRP (PRP group). Western blot assay was used to detect neurotrophic factors secreted by PRP. Nerve regeneration was assessed by motor function, electrophysiology, and histology studies. RESULTS: High levels of neurotrophin-3, angiopoietin-1, glial cell line derived neurotrophic factors, nerve growth factors and brain derived neurotrophic factors were demonstrated in PRP. Motor function recovery, compound motor action potentials, and axon count showed significant improvement in guinea pig treated with PRP. CONCLUSION: There was an improved functional outcome with the use of PRP in comparison with control. The increased nerve regeneration found in this study may be due to the neurotrophic factors secreted by PRP.

Neural Differentiation of Mesenchymal Stem Cells from Bone Marrow of Human Mastoid Process / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Reports of neural differentiation of mesenchymal stem cells suggest the possibility that these cells may serve as a source for stem cell-based regenerative medicine to treat neurological disorders. The purpose of this study was to generate neural cells by differentiation of bone marrow-derived mesenchymal stem cells that isolated from human mastoid process. MATERIALS AND METHOD: Human mesenchymal stem cells (hMSCs) isolated from human mastoid process bone marrow during mastoidectomy for chronic otitis media surgery were characterized using fluorescence-activated cell sorter. Induction of neural differentiation from hMSCs was performed using mitogenic factors (basic fibroblast growth factor, epidermal growth factor, forskolin, isobutylmethylxanthine), and the characterization of differentiated hMSCs was performed using immunohistochemistry, RT-PCR and whole cell patch clamp technique. RESULTS: hMSCs from bone marrow of mastoid process were isolated and cultured. Differentiated cells from hMSCs expressed mRNA transcripts for neuron specific markers, TUJ1 and neurofilament proteins (NF-L, NF-M) as determined by RT-PCR, and neuron specific markers, suhc as NeuN, TUJ1, microtubule-associated protein-2 (MAP2) and glial fibrillary acidic protein by immunohistochemistry. These cells showed voltagedependent sodium currents that was blocked by tetrodotoxin. CONCLUSION: hMSCs, which were isolated from human mastoid process bone marrow, were one of the good sources for stem cell-based regenerative medicine to treat neurological disorders.

The Early Change of Left Ventricular Function in Overweight and Obese Patients: Analysis With Tissue Doppler Echocardiography

BACKGROUND AND OBJECTIVES: Obesity is a cause of cardiac dysfunction. We analyzed the change of diastolic function with the increase of the body mass index (BMI) for the early detection of cardiac dysfunction in overweight and obese patients. To analyze the diastolic function, we measured the mitral valve early and late diastolic inflow velocities with performing Doppler studies (E, A) and the early and late mitral annulus velocities with performing tissue Doppler studies (E', A'). SUBJECTS AND METHODS: From January 2005 to October 2007, 2,684 cases were enrolled in this study. The patients had a normal cardiac size, normal systolic function, no regional wall motion abnormalities and no significant valve disease. Those patients with a history of congenital heart disease, renal failure and congestive heart failure were excluded. The BMI was checked and Doppler echocardiographic analysis, including tissue Doppler, was done. RESULTS: The left ventricle (LV) mass index (normal: 89.1+/-19.1, overweight: 95.7+/-18.4, obese: 97.2+/-18.9 g/m2, p or =25 kg/m2) and obese groups (BMI> or =30 kg/m2) than that of the normal group. On multiple logistic regression analysis, overweight was an independent risk factor for diastolic dysfunction with considering other risk factors such as hypertension, diabetes mellitus, age and gender. The risk of LV diastolic dysfunction was increased 2.13 times in the overweight group and 3.1 times in the obese group as compared with the normal group. CONCLUSION: With an increase of weight, diastolic function was worsened before the development of systolic dysfunction. This change was apparent in the overweight group. Tissue Doppler study on the mitral annulus is more sensitive to detect the change of diastolic function in overweight and obese patients.