Dankook University Dental Hospital

OBJECTIVE: The aim of this study was to investigate the effect of water on dental hard tissue ablation using Er:YAG laser as it relates to energy and pulse repetition rate, and determine the water flow rate that produces the most effective ablation at a given irradiation condition. BACKGROUND DATA: Er:YAG laser application leads to volumetric expansion and micro-explosions that result in hard tissue ablation. Ablation efficiency is improved when combined with fine water spray. MATERIALS AND METHODS: Extracted, healthy human molars were sectioned into two pieces and categorized into small groups related to water flow rate (1.69, 6.75, and 13.5 mL/min), pulse energy (250 and 400 mJ), and pulse repetition rate (5, 10, and 20 Hz). Within the combination of irradiation parameters, a laser beam was applied over enamel and dentin surfaces of the specimens, and the ablation amount was determined by differences in weight before and after irradiation. RESULTS: At a pulse energy of 250 mJ, the most effective ablation resulted from a water flow rate of 1.69 mL/min in both enamel and dentin. With 400 mJ/pulse, dentin removal was most effective at the water flow rate of 1.69 mL/min, whereas the efficiency of enamel ablation was the highest at 6.75 mL/min. Dental hard tissue ablated better as energy and pulse repetition rate increased. CONCLUSION: Effective ablation of dental hard tissue using Er:YAG laser requires that the appropriate water flow rate correspond properly to irradiation conditions. The results of this study suggest the following parameters; a water flow rate of 1.69 mL/min for enamel and dentin ablation at a pulse energy of 250 mJ and for dentin ablation at 400 mJ/pulse, and a water flow rate of 6.75 mL/min for enamel ablation at a pulse energy of 400 mJ, regardless of pulse repetition rate of 5, 10, and 20 Hz.

Translucent zirconia, manufactured by increasing the yttria content, offers improved translucency, but may have a negative effect on esthetic outcomes under clinical conditions such as discolored abutment because of the reflection of the underlying color. The purpose of this in vitro study was to compare the translucency parameter and masking ability of 3 mol % yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP (Katana HT)), 4Y-ZP (Katana STML), and 5Y-ZP (Katana UTML) with those of lithium disilicate (Rosetta SM). Zirconia and lithium disilicate specimens of 10 mm diameters and 0.8 and 1.5 mm thicknesses were fabricated. Their CIE L*a*b* values (L*, brightness; a*, red-green value; b*, yellow-blue value) were measured at the center of the specimens against black and white backgrounds using a spectrophotometer, and translucency parameter (TP) values were determined. The microstructure of the specimens was observed using scanning electron microscopy. Four cylindrical backgrounds of different shades were prepared. The zirconia and lithium disilicate specimens were placed on the backgrounds without any intervening medium. CIE L*a*b* values were obtained, and the color difference value (ΔE) was calculated. Thresholds for acceptability and perceptibility were assumed as ΔE = 5.5 and ΔE = 2.6, respectively, to evaluate masking ability. Data were compared using one-way analysis of variance and post-hoc was performed using Scheffe's test (α = 0.05). In zirconia specimens, the TP value increased as the yttria content increased from 3 mol %, through 4 mol % to 5 mol %, and all zirconia specimens showed lower TP values than lithium disilicate specimens did. All zirconia specimens showed optimal masking ability against a normal dentin shade (ND3) and acceptable masking ability against titanium at a minimum thickness of 1.5 mm. However, no zirconia specimen could mask severely discolored dentin (ND9), regardless of thickness. The decrease in zirconia thickness from 1.5 to 0.8 mm significantly increased translucency. Monolithic Y-TZP ceramics could mask a normal dentin background but could not mask severely discolored dentin at either 0.8 or 1.5 mm thicknesses.

Mandibular skeletal posterior anatomic limit for molar distalization in patients with Class III malocclusion with different vertical facial patterns Objective: The aim of this study was to compare the differences in mandibular posterior anatomic limit (MPAL) distances stratified by vertical patterns in patients with skeletal Class III malocclusion by using cone-beam computed tomography (CBCT). Methods: CBCT images of 48 patients with skeletal Class III malocclusion (mean age, 22.8 3.1 years) categorized according to the vertical patterns (hypodivergent, normodivergent, and hyperdivergent; n = 16 per group) were analyzed. While parallel to the posterior occlusal line, the shortest linear distances from the distal root of the mandibular second molar to the inner cortex of the mandibular body were measured at depths of 4, 6, and 8 mm from the cementoenamel junction. MPAL distances were compared between the three groups, and their correlations were analyzed. Results: The mean ages, sex distribution, asymmetry, and crowding in the three groups showed no significant differences. MPAL distance was significantly longer in male (3.8 2.6 mm) than in female (1.8 1.2 mm) at the 8-mm root level. At all root levels, MPAL distances were significantly different in the hypodivergent and hyperdivergent groups (p < 0.001) and between the normodivergent and hyperdivergent groups (p < 0.01). MPAL distances were the shortest in the hyperdivergent group. The mandibular plane angle highly correlated with MPAL distances at all root levels (p < 0.01). Conclusions: MPAL distances were the shortest in patients with hyperdivergent patterns and showed a decreasing tendency as the mandibular plane angle increased. MPAL distances were significantly shorter (~3.16 mm) at the 8-mm root level.

This report describes a case of teriparatide (TPTD) therapy for bisphosphonate (BP)-related osteonecrosis of the jaw induced after implant placement. A 75-year-old woman taking oral BP was referred with uncontrolled osteonecrosis of the mandible related to the implant placement. With conservative treatment, BP was suspended and daily subcutaneous injections of 20 μm/d TPTD were started. After 4 months of the therapy, fixture removal and sequestrectomy were performed. Histological analysis revealed necrotic lamellar bone and empty osteocytic lacunae. In contrast, multiple irregular reversal lines of the lamellar bone and active osteoblasts were noted adjacent to the lesion. There was a significant increase in serum C-terminal telopeptide cross-link of type 1 collagen and serum osteocalcin after commencement of the therapy. After 7 months off therapy, the serum levels of the 2 markers remained at a high level compared with the baseline.

PURPOSE: The aim of this case report is to present the longitudinal results of sinus grafting using a new demineralized bovine bone material (DBBM) in human cases. METHODS: A patient with a resorbed maxilla was treated by maxillary sinus grafting using a new deproteinized bovine bone material. After a healing period of 6.5 months, three implants were placed and restored. The patient was periodically recalled and followed up for 5 years after restoration. RESULTS: Twelve partially edentulous patients (average age, 55.7 years) were followed up. All patients had insufficient residual height in their maxillary posterior area and underwent maxillary sinus graft surgery to increase the height of their maxilla. In all, 27 fixtures were placed in the augmented bone area. On average, 8.6 months later, implants were loaded using provisional or final restorations. The observation period ranged from 27 to 75 months (average, 43.3 months), and the patients did not show any severe resorption of the graft material or any infection during this time. CONCLUSIONS: Our results show that the new DBBM is useful for a maxillary sinus graft procedure. Good healing responses as well as reliable results were obtained for an average follow-up period of 43.3 months.

AOT is a rare, non-invasive, benign (hamartomatous) epithelial lesion of odontogenic origin and accounts for 2% to 7% of all odontogenic tumors. AOT usually affects young patients, mostly during their second to third decades of life. Women are affected more frequently than men (male:female ratio=1:1.9), and the lesions tend to occur in the anterior maxillary region 5 . There are three types of AOT: a follicular type (73% of all cases), which has a central lesion associated with an impacted tooth; an extrafollicular type (24% of all cases), which has no relation with an impacted tooth; and a peripheral type (3% of all cases) 6 . Of the follicular types of AOT, 36% occur in the mandible. In one study of AOT affecting the mandible, only 28% of cases involved the mandibular incisor area 7 . Here, we present a case of AOT involving the mandible with an unerupted lateral incisor.

Sevoflurane is familiar to anesthesiologists as an inhaled anesthetic to induce and maintain anesthesia; however, it has not been widely used for sedation. Recently, the use of sevoflurane for inhalational sedation has been increasing. Moreover, in Korea, the use of sevoflurane for conscious or deep sedation in dental care for children and the disabled is increasing, primarily by dental anesthesiologists. In this article, we reviewed a sedation method using sevoflurane.

BACKGROUND: Awake craniotomy is a well-tolerated procedure for the resection of brain tumors residing within or close to the eloquent cortical areas. Monitored anesthesia care (MAC) is a dominant anesthetic approach for awake craniotomy; however, it is associated with inherent challenges such as desaturation and hypercapnia, which may lead to various complications. The prevention of respiratory insufficiency is important for successful awake craniotomy. As measures to avoid respiratory depression, the use of high-flow nasal cannula (HFNC) can improve patient oxygenation and monitor the monitoring the oxygen reserve index (ORi) can detect hypoxia earlier. CASE: We report two cases of awake craniotomy with MAC using HFNC and ORi. We adjusted the fraction of inspired oxygen of the HFNC according to the ORi level. The patient underwent successful awake craniotomy without a desaturation event or additional airway intervention. CONCLUSIONS: Combined HFNC and ORi monitoring may provide adequate oxygen reserves in patients undergoing awake craniotomy.

BACKGROUND: While evidence from preclinical and observational cohort studies have suggested potential disparities in tumour behaviour associated with the choice of intra-operative anaesthetics, clinical evidence of tumour recurrence and metastasis remains inconclusive. We aimed to compare the impact of intra-operative anaesthesia on oncologic outcomes following hepatectomy for hepatocellular carcinoma. METHODS: Adult patients scheduled for elective hepatectomy for hepatocellular carcinoma were assigned randomly (1:1) to either propofol-based total intravenous anaesthesia or sevoflurane-based inhalational anaesthesia. For recurrence-free survival, overall survival, intrahepatic recurrence-free survival and extrahepatic recurrence-free survival, the survival curves of the two groups were estimated using the Kaplan-Meier method and compared with the log-rank test. The primary outcome was one-year recurrence-free survival. RESULTS: Among the 536 patients enrolled, primary analysis comprised 228 and 226 patients in the total intravenous anaesthesia and sevoflurane-based inhalational anaesthesia groups, respectively. The probability of recurrence-free survival at one year was 79.1% (47 events) and 77.7% (50 events) in the total intravenous anaesthesia and sevoflurane-based inhalational anaesthesia groups, respectively (adjusted hazard ratio 1.04, 95%CI 0.72-1.52). The probability of intrahepatic and extrahepatic recurrence-free survival, as well as overall survival at one year, was not significantly different between total intravenous anaesthesia and sevoflurane-based inhalational anaesthesia: 81.3% (42 events) vs. 81.7% (41 events); 91.5% (19 events) vs. 88.8% (25 events); 99.1% (2 events) vs. 100.0% (no event), respectively. Subgroup analyses revealed that in patients undergoing open hepatectomy, total intravenous anaesthesia was associated with a significantly lower hazard of tumour recurrence or death (hazard ratio 0.49, 95%CI 0.25-0.95, p = 0.034), while in patients undergoing laparoscopic surgery, no significant difference was observed (hazard ratio 1.14, 95%CI 0.73-1.80, p = 0.558). DISCUSSION: Intra-operative anaesthesia technique did not affect postoperative recurrence and overall survival in patients with hepatocellular carcinoma undergoing hepatectomy.

Human bone marrow stem cells (hBMSCs) represent a promising regenerative material because of their mutipotency, including their ability to regenerate collagenous soft tissues. We previously found that water-soluble chitin (WSC) enhances the ability of human periodontal ligament stem cells (hPDLSCs) to synthesize collagen tissue. The aim of this study was to determine the effects of WSC on hBMSCs and hPDLSCs for the collagen synthesis both in vitro and in vivo. hBMSCs and hPDLSCs were isolated and expanded with or without 0.3 mg/mL WSC. A series of in vitro and in vivo analyses were performed to evaluate their characteristics as stem cell populations. Then, collagen and hydroxyproline assays were conducted using both in vitro and in vivo assay models, and the real-time polymerase chain reaction was performed to analyze the expression of collagen-related markers. WSC-treated and nontreated hBMSCs and hPDLSCs were transplanted into immunocompromised mice, and histology and immunohistochemistry analyses were conducted after 8 weeks. The in vitro results showed that those cells possessed the characteristics of mesenchymal stem cells. The amount of soluble collagen synthesized was significantly greater in WSC-treated hBMSCs than in the nontreated group; conversely, treatment of hPDLSCs with WSC decreased the formation of soluble collagen. The amount of insoluble collagen synthesized was greater in the WSC-treated groups than in the nontreated groups for both hBMSCs and hPDLSCs. The hydroxyproline contents of the regenerated soluble and insoluble collagens were similar. The expressions of mRNA for collagen types I-V, hyaluronic acid synthase 1 (HAS1), HAS2, and HAS3, and the LOX family were higher in WSC-treated hPDLSCs than in the nontreated group, whereas WSC increased the expression of collagen type III and decreased that of collagen type I in hBMSCs. The histology and immunohistochemistry results revealed that WSC significantly increased the amount of collagen formed in vivo by both types of stem cells. Collectively, treatment with WSC significantly enhanced the collagen-forming potentials of hBMSCs and hPDLSCs, but the collagen they produced exhibited distinctively different characteristics. These findings suggest that the appropriate stem-cell source should be chosen based on the purpose of the required regenerated tissue.

Basal cell adenoma (BCA) is a rare, benign neoplasm that most frequently arises in the parotid gland. We treated a 54-year-old female patient with BCA that had developed in the deep portion of the left parotid gland. The patient presented with gradual facial swelling with no other symptoms. We performed a total parotidectomy to excise the mass, but we preserved the facial nerve. Histopathology revealed a well-encapsulated mass. The tumor was composed of islands of comparatively uniform, small, dark, basaloid epithelial cells in the stroma. Histologic and immunohistochemical studies concluded that the BCA tumors were mostly trabecular. Postoperatively, there was no facial nerve weakness, and the tumor did not recur during the 24-month follow-up period.

Background. Few studies have tried to investigate the influence of socioeconomic inequalities on dental behaviors by considering the income and education levels as different dimensions of the independent variables in the adult Korean population.

Hydroxyzine is one of the most popular oral sedatives used in pediatric dentistry. This study aimed to investigate the safety and possible side effects of sedation using hydroxyzine in pediatric dentistry. "Hydroxyzine," "Dental sedation," "Child," and "Safety" and their associated synonyms were searched using the Cochrane Library, Embase, PubMed, KISS, KMBASE, and KoreaMed databases. Academic information and portals of DBpia and RISS were also perused. Altogether, 340 papers were found, among which a total of 24 papers were selected according to the detailed criteria. Nine studies used hydroxyzine as monotherapy, and 10 studies compared its safety when hydroxyzine used as multitherapy. In addition, seven studies employed a drug regimen wherein hydroxyzine was one of the components. All these studies revealed that the adverse events specific to hydroxyzine usage were drowsiness and dryness of the mouth, and that there were respiratory complications due to a synergistic reaction of hydroxyzine. Although classified as a histamine blocker, hydroxyzine with its sedative, antiemetic, anticonvulsant, and anticholinergic properties is an oral sedative available without serious adverse events, If the proper dosage of the drug is used and its synergistic effects with other drugs are ascertained in the route of administration.

Objectives Unmet needs for dental treatment are one of the potential contributing factors to poor oral health because oral health problems worsen if left untreated. This study aimed to demonstrate the prevalence of and the causes for unmet dental needs, and to evaluate the association between unmet needs for dental treatment and oral health status. Methods Data on 3,883 subjects aged ≥18 years from the Korean National Oral Health Survey 2006 were analyzed. Information regarding unmet needs for dental treatment was obtained using standardized questionnaires. Eight trained dentists examined decayed, missing, or filled teeth (DMFT). Multiple regression models were built to assess the association between unmet needs for dental treatment and the DMFT scores. Results The prevalence of perceived unmet needs for dental treatment was 34.7% among the adult Korean population. Economic constraints were the main cause (38.6%) for unmet dental needs. The average DMFT scores were higher in the subjects with unmet needs for dental treatment than in those without. In individuals with unmet needs for dental treatment within the past 1 year, the number of decayed teeth after adjusting for confounders was likely to be greater by 0.58 and that of missing teeth by 0.27 compared to that in their counterparts with no unmet dental needs in the past 1 year. Conclusions Perceived unmet needs for dental treatment were significantly associated with poor oral health status among the adult Korean population. Further studies are needed to clarify the direct and indirect effects of unmet needs for dental treatment on an individual's oral health status by investigating critical variables of the causal pathways among perceived dental needs, dental care utilization, and oral health status.

OBJECTIVES: The aim of the study was to investigate patients with coronavirus disease 2019 (COVID-19) who visited dental clinics for treatment and to analyse the occurrence of additional COVID-19-confirmed cases according to the type of dental treatment and use of personal protective equipment (PPE). METHODS: Interviews were conducted in November 2021 via telephone, and written questionnaires were administered to dental hygienists working at the 24 dental clinics selected for the study, visited by patients with COVID-19. The survey focused on the visit date, the treatment received, whether or not the dental personnel wore PPE while treating the patient, and how the dental clinic and the public health centre with jurisdiction over the clinic responded after the patient's visit. RESULTS: Additional confirmed cases occurred in two of the 24 dental clinics included. In both cases, scaling was performed, dental personnel did not use a face shield, and patients with COVID-19 were asymptomatic. In 14 of the 22 dental clinics where additional confirmed cases did not occur, the dental personnel did not use face shields, and in 10 clinics, the dental personnel wore dental masks but not a KF94 mask. Based on these findings, which were obtained before the advent of the omicron variant, COVID-19 cross-infection did not appear to be high in dental clinics. CONCLUSION: The rate of COVID-19 cross-infection before the advent of the omicron variant appeared to be low in dental clinics in Korea. Therefore, patients have no reason to delay necessary dental treatment if dental personnel put effort into wearing PPE.

목적: 치과용 연마기를 통한 캔디다균의 2차 감염성 여부를 알아보고자 하였다. 연구 재료 및 방법: 동일한 모형에서 제작된 상악 총의치를 캔디다균에 감염시키고, 멸균된 퍼미스와 휠 증류수를 이용하여, 치과기공용 연마기로 연마하였다. 이후 멸균된 상악 총의치를 연이어 연마한 뒤연마한 부위를 면봉으로 채취하여, 캔디다균을 배양하였다. 연마한 휠은 3일동안 상온에 노출시켜 24시간 간격으로 캔디다균의 잔존여부를 측정하였다. 결과: 연마한 멸균 총의치에서 다수의 캔디다균이 발견되었으며, 연마한 휠에서는 2일까지 캔디다균이 검출되었다. 결론: 의치 연마를 위한 치과기공용 연마기를 사용시 캔디다균의 감염가능성이 있기 때문에 감염방지책이 필요하다. Purpose: The purpose of this study was to evaluate the transmission of candida in denture by dental polishing lathe. Materials and Methods: Maxillary complete dentures made from the same model were infected with Candida albicans. The infected dentures were polished by dental polishing lathe with sterile pumice and distilled water. And then sterile maxillary complete dentures were polished with same method. Polishing surface was wiped with a cotton swab and the sample was checked for Candida albicans. The polishing wheel at room temperature was checked for Candida albicans every 24 hours for 3 days. Results: A considerable number of Candida was found on the polished sterile dentures. And the Candida albicans in polishing wheel was detected at up to two days. Conclusion: An anti-infection measure is urgently needed when dental polishing lathe is used for denture polishing, because of the possibility of fungal infection.

Objectives: Orthognathic surgery is a corrective intervention for maxillofacial deformities. Bleeding is a major concern for oral and maxillofacial surgeons. Various agents, such as hemocoagulase, tranexamic acid, and aprotinin have been developed to reduce intraoperative bleeding and transfusion requirements. Therefore, in this study we aimed to investigate the effects of hemocoagulase and tranexamic acid, as well as their simultaneous use, to reduce bleeding during orthognathic surgery. Patients and. Methods: This retrospective study included patients who had undergone simultaneous orthognathic surgery of the maxilla and mandible between January 2013 and September 2022 and were classified into three groups based on drugs administered: hemocoagulase (Botropase), tranexamic acid, and a combination of both drugs. We recorded patient age, sex, weight, blood loss, and duration of surgery. Red blood cell (RBC), hemoglobin, hematocrit, and platelet levels were measured before, immediately after, and one day after surgery. Results: No statistically significant differences were found in blood loss, RBC, hemoglobin, hematocrit, or platelet levels between any of the groups. There were no differences in the drug effects between Le Fort I and bilateral mandibular sagittal split osteotomies, with or without double genioplasty. However, there were significant reductions in RBC, hemoglobin, hematocrit, and platelet levels during genioplasty. Conclusion: Tranexamic acid, hemocoagulase, and their combination had similar efficacy in patients who underwent Le Fort Ⅰ and bilateral mandibular sagittal split osteotomies with and without genioplasty.

Objectives: Contemporary biometric technologies have been gaining traction in both public and private security sectors. Facial recognition is the most commonly used biometric technology for this purpose. We aimed to evaluate the ability of a publicly available facial recognition application program interface to calculate similarity scores of presurgical and postsurgical photographs of patients who had orthognathic surgery. Materials and Methods: Presurgical and postsurgical photographs of 75 patients who had orthognathic surgery between January 2018 and November 2020 in our department were used. Frontal photographs of patients in relaxed and smiling states were taken. The patients were classified into three groups: Group 2 had one-jaw surgery, Group 3 had two-jaw surgery to correct mandibular prognathism, and Group 4 had two-jaw surgery to correct facial asymmetry. For comparison, photographs of 10 participants were used as controls (Group 1). Two facial recognition application programs (Face X and Azure) were used to assess similarity scores. Results: The similarity scores in the two programs showed significant results. The similarity score of the control group, which did not undergo orthognathic surgery, was the highest. The results for Group 2, Group 3, and Group 4 were higher in the order of Group 2, Group 3, and Group 4. Conclusion: In this study, all orthodontic patients were recognized as the same person using the face recognition program before and after surgery. A significant difference in similarity results was obtained between the groups with both Face X and Azure and in both relaxed and smiling states.

Background: Intravenous sedation is effective for dental patients who are anxious. Recently, target-controlled infusion (TCI) has begun to be used widely to administer and titrate propofol and remifentanil during sedation. To investigate the effect and safety of the pharmacologic agents used in anesthetic department, we performed a retrospective study. Methods: Retrospective study of a series of dental procedure under intravenous sedation performed in department of anesthesiology in Dental Hospital of Dankook University was carried out with propofol or propofol/remifentanil between January and August 2011 and January and April 2012. All patients received oxygen by nasal cannula. The average propofol and remifentanil target was 0.5 μg/ml and 1.0 ng/ml, respectively using a TCI pump. The average peripheral oxygen saturation (SpO2), heart rate, blood pressure, respiratory rate, nasal end-tidal CO2 were recorded at 5-10 minute intervals. The age, gender, weight, procedure and sedation time, type of procedure were also recorded. Results: We included 22 cases of 19 adults (group A) and 6 cases of children (group B). In group A, 4 patients received propofol (group A-P), and 15 patients received propofol with remifentanil (group A-PR). In group B, 6 patients received propofol only. The mean age of group A was 41.1 years old and that of group B was 9.5 years old. No clinically significant complications were noted. There were no case of de-saturation <90%. The median respiratory rate was 13.1 (range 6 to 36) in group A and 19 (range 13 to 25) in group B. The median end tidal CO2 was 36.7 mmHg(range 8 mmHg to 56 mmHg) in group A and 41.7 mmHg (range 30 mmHg to 53 mmHg) in group B. Conclusions: Based on our results, dental sedation using propofol/remifentanil in adult and propofol in children with TCI pump seems to appear as a safe and effective procedure while performing dental procedure.

Although alveolar ridge preservation (ARP) has the advantage of reducing alveolar bone resorption after tooth extraction, weak primary stability occurs during implant placement. Immediate implant placement with open healing ARP (iARP) has been implemented to achieve primary stability and to take advantage of both immediate implantation and ARP. Herein, we describe three cases of iARP using deproteinized bovine bone mineral (DBBM) and native bilayer collagen membrane (NBCM) without primary closure. In all cases, delayed healing of the soft tissue was observed, but the implant and bone conditions were maintained without any complications for more than 19 months. Within the limitations of this report, iARP is considered a procedure that can overcome the disadvantages of immediate implant placement and ARP and take advantage.