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Abstract Background Appropriate communication with dental patients enhances treatment outcomes and patient satisfaction. Implementing simulated patient interviews courses can improve patient-centered care and reduce conflict during clerkship training. Therefore, this study explored the relationship among student participation in a situational simulation course (SSC), academic performance, clerkship performance, and objective structured clinical examination (OSCE) performance. Methods This study was conducted with a sample of fifth-year dental students undergoing clerkship training. After implementing a situational simulation course to investigate the relationship among participation in SSC, academic performance, clerkship performance, and OSCE performance, a path analysis model was developed and tested. Results Eighty-seven fifth-year dental students were eligible for the SSC, and most (n = 70, 80.46%) volunteered to participate. The path analysis model revealed that academic performance had a direct effect on OSCE performance (β = 0.281, P = 0.003) and clerkship performance (β = 0.441, P

Abstract Background This study examines the oral health benefits of heat-killed Lacticaseibacillus paracasei GMNL-143, particularly its potential in oral microbiota alterations and gingivitis improvement. Methods We assessed GMNL-143’s in vitro interactions with oral pathogens and its ability to prevent pathogen adherence to gingival cells. A randomized, double-blind, crossover clinical trial was performed on gingivitis patients using GMNL-143 toothpaste or placebo for four weeks, followed by a crossover after a washout. Results GMNL-143 showed coaggregation with oral pathogens in vitro, linked to its surface layer protein. In patients, GMNL-143 toothpaste lowered the gingival index and reduced Streptococcus mutans in crevicular fluid. A positive relationship was found between Aggregatibacter actinomycetemcomitans and gingival index changes, and a negative one between Campylobacter and gingival index changes in plaque. Conclusion GMNL-143 toothpaste may shift oral bacterial composition towards a healthier state, suggesting its potential in managing mild to moderate gingivitis. Trial registration ID NCT04190485 ( https://clinicaltrials.gov/ ); 09/12/2019, retrospective registration.

Background/purpose: Bacterial infection was the major etiology for pulpal/root canal infection. This study aimed to investigate the activation of toll-like receptor-3 (TLR) on cyclooxygenase-2 (COX-2) expression and prostaglandin E2 (PGE2) and PGF2α production of human dental pulp cells (HDPCs) and associated signaling. Materials and methods: HDPCs were exposed to different concentrations of Poly (I:C) (a TLR3 activator). Cell viability was determined by 3- (4,5-Dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay and alkaline phosphatase (ALP) activity was evaluated by ALP staining. Activation of extracellular signal-regulated kinase (ERK) and p38 by Poly (I:C) was determined by immunofluorescent staining. The COX-2 protein expression was analyzed by Western blot. PGE2 and PGF2α production was measured by enzyme-linked immunosorbent assay. The mRNA expression was studied by real-time polymerase-chain reaction. Moreover, HDPCs were exposed to Poly(I:C) with/without U0126 or SB203580 treatment and analysis of COX-2 expression and prostanoid production were conducted. Results: Poly (I:C) showed little effect on ALP activity, but decreased viability of HDPCs. It stimulated COX-2 mRNA and protein expression. Poly (I:C) induced PGE2 and PGF2α production of HDPCs. Poly (I:C) activated p-ERK, and p-p38 protein expression. Treatment by U0126 (a mitogen-activated protein kinase kinase (MEK)/ERK inhibitor) and SB203580 (a p38 inhibitor) attenuated Poly (I:C)-induced COX-2 mRNA and protein expression as well as PGE2 and PGF2α production. Conclusion: TLR3 activation is involved in the infection and inflammatory responses of pulp tissues, via MEK/ERK, and p38 signaling to mediate COX-2 expression as well as PGE2 and PGF2α production, contributing to the pathogenesis and progression of pulpal/periapical diseases.

Abstract Background A phase-III interdisciplinary quality improvement program, the preanesthetic oral examination (PAOE), was implemented as a new program in an academic medical center to prevent perioperative dental injuries. This study was aimed at surveying the perceived service quality and satisfaction of patients who had undergone PAOE based on the SERVQUAL model. Methods This cross-sectional survey was conducted at the Kaohsiung Medical University Hospital using convenience sampling. Patients referred for PAOE (PAOE group) and those who had voluntarily availed dental services (control group) were recruited. A modified SERVQUAL questionnaire was used to assess the perceived service quality and patient satisfaction with dental services. Cronbach’s alpha for SERVQUAL was 0.861. Results We enrolled 286 (68.8%) and 130 (31.2%) participants in the PAOE and control groups, respectively. The path analysis revealed that the PAOE group scored lower in dimensions of reliability (β = -0.074, P = 0.003), responsiveness (β = -0.148, P = 0.006), and empathy (β = -0.140, P = 0.011). Furthermore, reliability (β = 0.655, P

Abstract Background Digital dental technology (DDT) has progressed and been introduced to Taiwan in the recent years, gradually changing the industry ecology. Many studies have demonstrated that DDT is more accurate and faster than conventional dental technology. However, there is a paucity of research exploring dental technicians’ perspectives on digital dental techniques, and their burnout, job satisfaction, and turnover intention. Methods This cross-sectional survey with convenience sampling was conducted at the conference venue of the Taiwan Association of Dental Technology to investigate the perspectives of dental technicians. We used the snowballing method in this study; two sampling methods were adopted, a convenience sampling of dental technicians to complete a survey, followed by asking the survey participants of the convenience sample to invite their colleagues to participate in the online survey. The survey questionnaire included questions on demographics, work-related information, acceptance and experiences of dental technicians toward DDT, occupational burnout, job satisfaction, and turnover intention. Regression models were used to determine the predictors of job satisfaction and determinants of turnover intention. Results In total, 341 valid questionnaires were obtained. Overall, the participants reported long working hours (95.5%), positive score on the DDT acceptance scale, moderate job satisfaction, higher personal burnout, and work burnout, along with lower over-commitment. Among them, 32.9% and 28.2% reported the intention to leave their organization and profession, respectively. The stepwise multiple regression model revealed that higher work burnout decreased job satisfaction, while higher DDT acceptance and position as employer increased job satisfaction. The binary logistic regression models revealed that geographical area of workplace, work burnout, and job satisfaction were significant predictors of turnover intentions. Conclusions Many Taiwanese dental technicians reported turnover intentions and higher burnout. With the trend of digitalization in the dental industry, even though most dental technicians had a positive outlook toward DDT, its influence on job satisfaction appears limited. Retaining good and professional talents required of a dental technician is crucial, especially as Taiwan’s dental care becomes increasingly specialized. Strategies for improving the work environment and occupational health of dental technicians should thus be the focus of future studies.

Abstract Liver transplantation (LT) candidates often present with poor oral hygiene, which could potentially lead to systemic infections and sepsis owing to their cirrhotic state. In this study, we investigated the oral health status of LT candidates and propose guidance for the detection and treatment of encountered oral lesions among these patients. The decayed, missing, and filled teeth (DMFT) index was determined through oral examination. The presence of dental calculus was detected using panoramic radiography and defined by the radiopaque dental calculus (RDC). From January 2011 to August 2018, 56 LT candidates were enrolled with a median follow‐up of 39 months. The overall mean numbers of decayed, missing, and filled teeth among these patients were 2.7 ± 2.8, 10.9 ± 8.3, and 5.4 ± 4.5, respectively. Eighteen patients (32.1%) had RDC. The 5‐year survival rates of all 56 patients was 57.7%, while that of those who either received LT (23 patients) or not were 82.1% and 39.8%, respectively. A Cox regression model revealed better overall survival of patients after LT (adjusted hazard ratio [aHR] = 0.067, p = 0.001), worse survival among patients with RDC (aHR = 3.468, p = 0.010), at Child–Pugh stages B and C (aHR for stage B = 11.889, p = 0.028; aHR for stage C = 19.257, p = 0.013) compared to patients at Child–Pugh stage A, and those with a model for end‐stage liver disease (MELD) score ≥25 (aHR = 13.721, p = 0.018). This study demonstrates that RDC was associated with worse prognosis in LT candidates. We therefore recommend that interprofessional collaboration should be a routine preoperative procedure for the evaluation of oral hygiene among LT candidates.

Background/purpose: Dental visits are a high risk activity during the COVID-19 pandemic. This study investigated the utilization of emergency dental services and clinical practical attitudes of dental residents in this period. Materials and methods: Retrospective chart data from 13th November 2019 to 31st March 2020 in Kaohsiung Medical University Hospital, Taiwan were used. We obtained electronic medical records to review data from 515 patients who visited the emergency department with dental complaints and we contacted the 26 residents assigned to act as primary care providers to participate in this study. Results: After the COVID-19 outbreak, 17% fewer patients had dental emergency utilization at a hospital emergency center relative to the previous period. A survey of residents also showed a decline in the number of patients. There were no significant differences of patients' problems and diagnoses between the two periods. After the COVID-19 outbreak, 61.5% of the residents were afraid of being infected by a patient's disease and the proportions of dentists wearing waterproof gowns, face shields, and surgical hair caps were 76.9%, 88.5%, and 76.3%, respectively. These variables increased significantly after the outbreak of COVID-19. Conclusion: Despite the trend of a decreased number of patients, their utilization of dental emergency services seems to be similar before and after the COVID-19 outbreak, possibly related to strict hospital infection control policies and the relatively low number of COVID-19 confirmed patients internationally at that time.

Background/purpose: It is not clear whether the ground surface of resin-based composite (RBC) polymerized requires the application of an adhesive with/without a silane to improve bond strength. This study investigated the bond strength of RBC repaired within 24 h via the application of adhesive with/without a silane. Materials and methods: Seventy RBC blocks were prepared and assigned to either 0 or 24 h repair stage. Each stage was divided into seven groups: a control group with no surface roughening or applied adhesive, a surface-roughened group with no applied adhesive, two surface-roughened groups treated with a G-aenial Bond adhesive and a BeautiBond Multi adhesive, two surface-roughened groups treated with the previously-mentioned adhesives as well as silane coupling agents, and one group treated with a Single Bond Universal silane-containing adhesive. Microtensile bond strength (μTBS) measurements were performed after the repaired RBC blocks of each group (n = 5) had been immersed in a 37 °C water bath for 24 h. The failure mode of each sample was determined, and the data were analyzed via one-way analysis of variance and Dunnett's test (p = 0.05). Results: Regardless of the repair stage, the μTBS values of the adhesive-only and silane-adhesive groups did not differ significantly from those of the control group (p > 0.05). Only the no-adhesive groups exhibited a significantly time-dependent increase in adhesive failure rate. Conclusion: Our results suggest that the application of adhesives either with or without silane can significantly increase the bond strength of repairs to RBCs polymerized within 24 h.

Abstract Patient‐dentist discourse is a core nonoperational competency in dental education. The skills of querying patients and responding to questions are noncognitive attributes, and their evaluation by the standardized patient objective structured clinical examination (OSCE) is particularly necessary. However, it is not clear whether students' test anxiety affects these attributes. This study aims to examine the relationship between dental students' state‐trait anxiety, noncognitive performance, and examination results during their first OSCE. A single dental school cohort (n = 226) of 5 year students attending their first clinical examination from 2014 to 2017 was studied. Participants completed the Chinese Mandarin Version State‐Trait Anxiety Inventory Y form before taking the OSCE. The difference between state and trait anxiety levels was compared by paired t test. Gender differences and the effect of age group in these anxiety levels were analyzed using multivariate analysis of variance. Moreover, gender, age group, state anxiety, and trait anxiety scores were compared with the OSCE items of noncognitive performance using a chi‐square test. Students showed significantly higher state anxiety than trait anxiety levels; moreover, women showed significantly higher state anxiety than men. Furthermore, gender, age group, state anxiety, and trait anxiety had no association with the noncognitive performance examination results. Most participants showed moderate state and trait anxiety levels during their first OSCE. Further, the state‐trait anxiety had no significant effect on their noncognitive performance. However, 26.5% of participants did not pass the examination; therefore, dental educators should increase communication skill training courses during clerkship training to improve students' noncognitive attributes.

Abstract Background We aimed to investigate the load-induced strain variation in teeth with unrestored and resin-based composite restored non-carious cervical lesions (NCCLs). Methods Twelve extracted premolars were provided for measuring buccal-side root NCCLs. Strain gauges were fixed at four measuring sites of each tooth, two at the buccal surface and two at the lingual surface. NCCLs were prepared with occlusal margins at the cemento-enamel junction. A static 9-kg load was applied at seven occlusal loading points: buccal cusp tip (BC), inner inclination of the BC, lingual cusp tip (LC), inner inclination of the LC, center of the mesial marginal ridge or distal marginal ridge, and center of the central groove. The strain was detected at each site in teeth with NCCL depths of 0 (control), 0.5, 1.0, and 1.5 mm. Each NCCL was restored using an adhesive composite resin, and the strains were re-measured. Results The strains at the NCCL occlusal and gingival margins decreased with increasing defect depths, and the effect was significant when the depth of the defect was 1.5 mm. Loading on the buccal and lingual cusps induced prominent strain variation. The strains at all depth distribution recovered to nearly intact conditions when the NCCLs were restored. Conclusions NCCLs at 1.5 mm depth are detrimental, but they can be restored using resin composites. Clinical significance The existence of NCCLs should not be ignored. The depth of the NCCL may affect the progression of the lesion. Resin composite restoration is an appropriate method for preventing persistent NCCL deterioration.

Background/purpose: Electrolyzed water has been identified as an effective disinfectant that could represent as an alternative to sodium hypochlorite. Unfortunately, it remains unclear whether the texture or physical properties of dentin are affected by the application of electrolyzed water of different acidities. This study was aimed to assess the influence of electrolyzed waters with differing pHs on the demineralizing of inner dentin. Materials and methods: The coronal superficial dentin of 20 human molars was exposed and further bisected into two pieces perpendicular to the dentin surface. The samples were immersed in strongly acidic electrolyzed water (AW group), neutral electrolyzed water (NW group), 5% sodium hypochlorite (positive control, NL group), or deionized water (negative control, DW group). Microhardness of the inner layer dentin was measured at a depth of 25 and 50 μm beneath the superficial surface layer every 5 up to 60 min. Results: At a depth of 25 μm, microhardness decreased with increasing immersion time in all but the DW group. The AW group exhibited a decreasing trend from the first 5 min that became significant after 35 min of immersion and was the most rapid decrease in the four groups. The rate of decline in the NW group was low and similar to that of the NL group. Both NW and NL groups exhibited significantly less demineralization than the AW group after 15 min of immersion. No significant microhardness change was found at a depth of 50 μm in any of the samples. Conclusion: AW produces a more pronounced softening of dentin than NW at a depth of 25 μm. Keywords: Dentin, pH, Microhardness, Electrolyzed water, Tooth demineralization, Mouthwashes

Background/purpose: Research on work stress and occupational burnout among Taiwanese dental staff is scarce. Thus, this study aimed to explore work stress and occupational burnout among dental staff in a medical center. Materials and methods: This study is a cross-sectional survey that included the dental staff of a medical center in Taiwan. They were asked to complete self-reported questionnaires anonymously. The Questionnaire on Medical Workers' Stress (QMWS) was used to assess work stress, and the Maslach Burnout Inventory-Human Service Survey (MBI-HSS) was used to evaluate occupational burnout. In total, 108 valid questionnaires were collected, with a response rate of 79.9%. Data were analyzed using independent t-tests, one-way analysis of variance, Pearson's correlation, and stepwise linear regression. Results: Overall QMWS score indicated that visiting staff perceived significantly higher stress than post-graduate year residents. Average scores of MBI-HSS showed dental assistants' scores as similar to those of high burnout groups; visiting staff and moderate burnout groups had similar scores. Stepwise regression analyses revealed that the significant predictor of emotional exhaustion was the QMWS score, of depersonalization were working as a dental assistant and QMWS score, and of personal accomplishment was holding a teaching position. Conclusion: Work stress and occupational burnout were common among dental staff; this may affect patient safety and should be valued. A stress management program is recommended to promote mental health of dental staff, along with adjustment of working environment, performance evaluation, and promotion systems. Keywords: Burnout, Stress, Dentist, Dental assistant, Medical center

Background The volume of literature about serious gaming in dental education has increased, however, none of the previous studies have developed a serious game for closing the gap between preclinical and clinical training. Objective Virtual Dental Clinic (VDC) is a serious game that was created to help develop clinical reasoning skills in dental students. This study aimed to evaluate VDC as an educational tool and its effectiveness on clinical skill and knowledge gain among clerkship dental students. Methods The following three stages of VDC design and testing were addressed from 2016 to 2020: development, validation, and application. The VDC was developed using Unity game engine. In the validation stage, the content validity was reviewed by five visiting staff; construct validity and face validity were examined by 9 postgraduate-year dentists and 14 clerkship dental students. Concurrent validity and predictive validity were examined by 34 fifth-year dental students during their clerkship from September, 2018 to May, 2019, the associations between VDC experiences, clerkship performance, and the score on a national qualification test were explored. In the application stage, the VDC was set up as a self-learning tool in the Family Dentistry Department from August, 2019, quantitative and qualitative analyses were conducted using the 92 clerkship students’ feedback. Results The VDC showed good validity and a high potential for education in practice. Students who have used VDC received significantly higher scores on qualification test (p = 0.029); the VDC experiences significantly predicted higher performance score on periodontics (p = 0.037) and endodontics (p = 0.040). After the outbreak of COVID-19 pandemic, significantly higher proportion of students confirmed the value of VDC as an assistant tool for learning clinical reasoning (p = 0.019). Conclusions The VDC as an educational tool, and the effectiveness on clinical reasoning skills and knowledge gain among clerkship dental students has been validated and confirmed in this study.

The objective of study was to investigate the correlation between the mechanical strengths [insertion torque (IT); resonance frequency (RF); and horizontal pullout strength (HPS)] and gripping volume (GV) of mini-implants. Thirty mini-implants of three types (Type A: 2 mm × 10 mm, cylindrical, titanium alloy; Type B: 2 mm × 10 mm, tapered, stainless steel; and Type C: 2 mm × 11 mm, cylindrical, titanium alloy) were inserted 7 mm into artificial bones. One-way analysis of variance and Spearman's test were applied to assess intergroup comparisons and intragroup correlations. The null hypothesis was that no statistically significant correlations exist between the GV and mechanical strengths (IT, RF, and HPS). In the IT test, Type C (14.2 Ncm) had significantly (p=0.016) greater values than did Type A (12.4 Ncm). In the RF analysis, no significant difference was observed among the three types of mini-implants. In the HPS test, Type C (388.9 Ncm) was significantly larger than both Type B (294.5 Ncm) and Type A (286 Ncm). In the GV measurement, Type C (14.4 mm3) was significantly larger than Type B (11.4 mm3) and Type A (9.2 mm3). Type A and Type B exhibited no significant correlations among the tests. Therefore, the null hypothesis was accepted. Although no significant correlation was noted between the GV and mechanical strengths (IT, RF, and HPS), we observed a trend that the mechanical strengths (IT, RF, and HPS) of the mini-implants corresponded to the order and values of GV (Type C > Type B > Type A).

The purpose of this study was to investigate the correlation between postoperative stability and a change in tongue area after treatment of mandibular prognathism. Twenty-six patients, who were treated for mandibular prognathism using intraoral vertical ramus osteotomy, were evaluated cephalometrically. A set of three standardized lateral cephalograms were obtained from each participant preoperatively (T1), immediately postoperatively (T2), and after 2 years postoperatively (T3). Student t test and Pearson correlation coefficient were used for statistical analysis. Immediately after the surgery (T12), the setback of the menton (Me) was 12.9 mm (p

We investigates the effect of the anchor area on the mechanical strengths of infrazygomatic mini-implants. Thirty mini-implants were divided into three types based on the material and shape: Type A (titanium alloy, 2.0×12 mm), Type B (stainless steel, 2.0×12 mm), and Type C (titanium alloy, 2.0×11 mm).The mini-implants were inserted at 90° and 45° into the artificial bone to a depth of 7 mm, without predrilling. The mechanical strengths [insertion torque (IT), resonance frequency (RF), and removal torque (RT)] and the anchor area were measured. We hypothesized that no correlation exists among the mechanical forces of each brand. In the 90° tests, the IT, RF, and RT of Type C (8.5 N cm, 10.2 kHz, and 6.1 N cm, respectively) were significantly higher than those of Type A (5.0 N cm, 7.7 kHz, and 4.7 N cm, respectively). In the 45° test, the RFs of Type C (9.2 kHz) was significantly higher than those of Type A (7.0 kHz) and Type B (6.7 kHz). The anchor area of the mini-implants was in the order of Type C (706 mm2)>Type B (648 mm2)>Type A (621 mm2). Type C exhibited no significant correlation in intragroup comparisons, and the hypothesis was accepted. In the 90° and 45° tests, Type C exhibited the largest anchor area and the highest mechanical strengths (IT, RF, and RT) among the three types of mini-implants. The anchor area plays a crucial role in the mechanical strength of mini-implants.

The microstructural characteristics and Young’s modulus of the as-cast Ti–15Ta–15Nb alloy are reported in this study. On the basis of the examined XRD and TEM results, the microstructure of the current alloy is essentially a mixture (α + β+ α′ + α″ + ω + H) phase. The new H phase has not previously been identified as a known phase in the Ti–Ta–Nb alloy system. On the basis of examination of the Kikuchi maps, the new H phase belongs to a tetragonal structural class with lattice parameters of a = b = 0.328 nm and c = 0.343 nm, denoting an optimal presentation of the atomic arrangement. The relationships of orientation between these phases would be {0001}α//{110}β//{1¯21¯0}ω//{101¯}H and (011¯0)α//(11¯2)β//(1¯010)ω//(121)H. Moreover, the Young’s modulus of the as-cast Ti–15Ta–15Nb alloy is approximately E = 80.2 ± 10.66 GPa. It is implied that the Young’s modulus can be decreased by the mixing of phases, especially with the presence of the H phase.

The aim of this study was to investigate the effect of incorporating low copper (0, 0.5, 1, 1.5, and 2 wt.%) additions into as-forged AISI 304 stainless steel (304SS). The microstructures and mechanical properties of the steel were examined using scanning electron microscopy and a universal testing machine. The antibacterial properties of the Cu-bearing 304SS specimens were investigated using Escherichia coli. Each specimen was soaked in artificial saliva to detect the release of copper ions through inductively coupled plasma atomic emission spectrometry. The addition of copper had no significant effect on the microstructure of the as-forged Cu-bearing 304SS, but it slightly increased its maximum tensile strength. The antibacterial rate of the as-cast and as-forged 304SS with 2 wt.% Cu was over 80%, which corresponded to an increase in the release of copper ions. This study demonstrates that low-Cu-content stainless steel can reduce bacteria and can be a suitable material for the oral environment because of the low release of Cu ions.

This study aimed to compare the insertion torque (IT), resonance frequency (RF), and removal torque (RT) among three microimplant brands. Thirty microimplants of the three brands were used as follows: Type A (titanium alloy, 1.5-mm × 8-mm), Type B (stainless steel, 1.5-mm × 8-mm), and Type C (titanium alloy, 1.5-mm × 9-mm). A synthetic bone with a 2-mm cortical bone and bone marrow was used. Each microimplant was inserted into the synthetic bone, without predrilling, to a 7 mm depth. The IT, RF, and RT were measured in both vertical and horizontal directions. One-way analysis of variance and Spearman's rank correlation coefficient tests were used for intergroup and intragroup comparisons, respectively. In the vertical test, the ITs of Type C (7.8 Ncm) and Type B (7.5 Ncm) were significantly higher than that of Type A (4.4 Ncm). The RFs of Type C (11.5 kHz) and Type A (10.2 kHz) were significantly higher than that of Type B (7.5 kHz). Type C (7.4 Ncm) and Type B (7.3 Ncm) had significantly higher RTs than did Type A (4.1 Ncm). In the horizontal test, both the ITs and RTs were significantly higher for Type C, compared with Type A. No significant differences were found among the groups, and the study hypothesis was accepted. Type A had the lowest inner/outer diameter ratio and widest apical facing angle, engendering the lowest IT and highest RF values. However, no significant correlations in the IT, RF, and RT were observed among the three groups.

Background/purpose: This study evaluated the fracture resistance of different metal substructure designs for implant-supported porcelain-fused-to-metal (PFM) crowns. Materials and methods: Eighteen PFM crowns were fabricated using different metal substructure designs and were conventionally cemented on an implant abutment analog. The crowns were divided according to the metal substructure design for manufacturing the metal framework into three groups of six specimens each: Group A had a minimum required thickness; Group B had a conventional design; and Group C had a wrinkled design. After applying a load of 200 N at a frequency of 2 Hz with 300,000 cycles of dynamic loading, all specimens were tested for fracture resistance using compression loading on the buccal functional cusp. Results: Among these three groups, Groups A and B, respectively, had the minimum and maximum fracture resistance strengths. Respective data for Groups A, B, and C were 111.13 ± 27.15 kg, 236.13 ± 39.21 kg, and 188.63 ± 12.10 kg. Statistically significant differences were observed among the three groups (P

Background/purpose: Although proper training of medical and dental interns is particularly important, there are no studies to date in Taiwan examining the quality of dental services provided to the public by interns. The purpose of study is to investigate the significant factors that influence the patient's satisfaction with the quality of dental treatment provided by Interns. Materials and methods: This study randomly selected patients from a dental department in a medical center located in southern Taiwan and used a structured questionnaire and response scales (Likert) to investigate the level of emphasis and satisfaction of patients with the dental treatment provided by interns in February to April 2004 (52 total valid questionnaires). Results: With regard to technical competence compared to that of dentists, we found statistically significant differences according to the type of treatment received, gender, marital status, educational level attained, and household income (P

Background/purpose: In this study, we investigated outcomes for conventional deltopectoral (DP) flaps and L-extension deltopectoral (L-DP) flaps in head-and-neck reconstructions. Materials and methods: Twenty-three conventional DP flaps and 10 L-DP flaps were created in 33 patients. The latter flaps were applied with no delay. The flaps were folded only in the L-DP-flap group. Seven of 10 L-DP flaps were folded to become bilayered flaps in order to repair full-thickness defects. Flap success rates and complication rates were compared between the conventional DP-flap and L-DP-flap groups. Results: Success rates were 91.3% in the DP-flap group and 90% in the L-DP-flap group. Overall complication rates of the transferred flaps were 30.4% and 40% for DP and L-DP flaps, respectively. Complications in the two groups were analyzed by a Chi-square test, and no significant differences were found. Conclusions: Although the DP flap is considered to be the “aged workhorse” in contemporary head-and-neck reconstructions, it was shown to be a beneficial regional flap with a dependable pedicle and easy technique. The L-DP flap is of value particularly when used to treat full-thickness defects of the head-and-neck.

Background/purpose: New modified mini-implants are used in orthodontic practice to reinforce palatal anchorage. The aim of this study was to evaluate the anchorage strengths of palatal mini-implants in terms of their vertical and horizontal pullout strengths. Materials and methods: Thirty palatal mini-implants (2 mm in diameter) of three brands (Absoanchor, Bio-Ray, and Lomas) were manually driven into artificial bone (Sawbones) to a depth of 5 mm. Their vertical and horizontal pullout strengths were measured using a material testing machine. The Kruskal–Wallis test was used to assess differences among brands (P

Background/purpose: Different denture cleaning methods have different effects. The purpose of this study was to evaluate the efficiency of six different denture cleaning methods to remove Candida albicans that had accumulated on denture-based materials. Materials and methods: We generated 140 identical acrylic resin specimens and soaked them in a suspension of C albicans. The reduction in microorganism counts after application of the different denture cleaning methods was calculated. Six cleaning methods were evaluated: a mechanical method of brushing with a toothbrush, a chemical method of soaking in a commercial cleansing tablet solution, a combined method of brushing and soaking in a commercial cleansing tablet solution, a chemical method of soaking in a commercial mouthwash solution, irradiation in an ultraviolet (UV)-light e-box, and soaking in distilled water. The effectiveness of the denture-cleaning methods in reducing C albicans was evaluated following a single cleaning event. Results: The denture cleaning techniques had considerably different efficacies in reducing C albicans. There was no significant difference among the effectiveness levels of cleaning by brushing, soaking in a commercial cleansing tablet solution, or a combination of both in removing C albicans. Similarly, the effectiveness levels of soaking in a commercial mouthwash solution or irradiation in a UV-light e-box were statistically similar. Conclusion: Compared to other methods, brushing, soaking in a commercial cleansing tablet solution, or a combination of both methods can significantly reduce the adherence of C albicans to denture samples. Compared to soaking in distilled water, soaking in a commercial mouthwash solution or irradiation with UV-light had more significant cleaning effects, but these methods were not as effective as the aforementioned three methods.

The aims of this preliminary study were to present a modified mandibular splint together with a treatment regimen and to evaluate their effects on the treatment of reciprocal joint sounds of the temporomandibular joint (TMJ). The study participants were recruited from 312 consecutive patients in the temporomandibular disorder clinic of a medical center in Taiwan from January 2003 to December 2003. From among these, 59 cases with typical reciprocal clicking were selected for this study. All participants were treated with a modified mandibular splint and then followed up for 6 months. Successful treatment was defined as leading to the disappearance of the joint sounds of TMJ, as described by patients. Based on clinical evaluation, the overall success rate was 71.2% (42/59) with minimal temporary complications. Patients with clicking at less than 3.5 cm of interincisal opening had a success rate of 92.5%, which was higher than the success rate of patients with clicking at a mouth opening of 3.5 cm or more. This study showed that a modified mandibular splint can be used to treat reciprocal clicking of the TMJ effectively and encouraged us to conduct further study on the efficacy of this splint to treat disc displacement with reduction of TMJ using magnetic resonance imaging examination.

Oral appliances are a range of devices that are designed to alter upper airway patency. The efficiency of these appliances for treatment of obstructive sleep apnea (OSA) has been rarely discussed. This case report describes two designs of mandibular repositioning appliances used to treat OSA. A 36-year-old man was diagnosed with mild OSA by his physician. A single-piece, soft oral appliance and a two-piece, acrylic appliance were used in this patient. Polysomnography was performed three times (baseline, and with the single-piece, and two-piece appliances). The apnea/hypopnea index was improved significantly with both appliances, but to a greater degree with the single-piece soft appliance. Our study concluded that oral appliances may assist in the management of OSA.

Currently, the development of biomaterials has focused on having a low Young’s modulus, biocompatibility, corrosion resistance, and antibacterial properties. Ti–Nb alloys have higher research value due to their excellent corrosion resistance and low Young’s modulus. In recent years, the antibacterial properties of materials have been enhanced by the addition of Ag and Cu. Therefore, the corrosion resistance and antibacterial properties of the Ti–12Nb–1Ag alloy formulated in the current study were investigated and compared to those of commonly used Ti alloys, G2 pure Ti (ASTM B348 CP Grade 2), and Ti–6Al–4V, via electrochemical and E. coli antibacterial tests. Meanwhile, we also carried out a microstructural analysis to investigate the composition of the alloy. The results were as follows: (1) The electrochemical test demonstrated that Ti–12Nb–1Ag had a higher corrosion resistance than Ti–6Al–4V, which is similar to the properties of pure Ti. (2) The E. coli antibacterial test demonstrated that the sterilization rate of Ti–12Nb–1Ag was higher than that of the Ti–6Al–4V alloy and pure Ti. (3) The microstructural analysis revealed that Ti–12Nb–1Ag had an acicular martensite structure, with nano-Ag precipitates observed. Based on the results of the E. coli antibacterial test and the principles of sterilization of nano-precipitates and Ag, we inferred that the nano-Ag precipitates of Ti–12Nb–1Ag enhanced the antibacterial properties of the newly developed biomaterial, which is, namely, the Ti–12Nb–1Ag alloy.

Clinically, many implant cases with different angulation over the lower posterior area have been found. The purpose of this study was to analyze the bony stress with different implant tilting during normal masticatory load using the finite element method (FEM), with the hope of discovering a desirable installation of implant. Athree-dimensional finite element method was employed to analyze the bony stress generated by different angulation designs (15°) of implant bodies. Eight solid models of the mandibular first and second molars were built up and then transferred to a mesh model in FEM (ANSYS) to perform a stress analysis. A simulated load (400N) was applied to the splinted crowns with vertical and horizontal forces. The loading sites were on the central fossa of the splinted crowns. For stress distribution, some designs will be better than a parallel installation. The results suggested that not all implant bodies tilting with the splinted crowns lead to stress concentration.

A soft palate defect may result from surgical resection, and its consequences could include hypernasal speech and nasal regurgitation of food and liquids. A speech aid prosthesis fabricated for patients can improve nasal emission during speech, and assist in preventing nasal regurgitation of food. This article presents a case of the reconstruction of a soft palate defect by prosthetic obturation.

Occlusal splints are a standard method to treat disc displacement with reduction of the temporomandibular joint (TMJ). They can be classified into three major groups on the basis of function: stabilization splints, distraction splints (pivot), and anterior repositioning splints. The aim of this paper is to introduce a modified mandibular splint, the Kaohsuing Medical University splint, and its associated treatment regimen for management of disc displacement with reduction of the TMJ. The key points for fabrication of the KMU splint include the occlusal surface of the mandibular splint must be indented and average bite elevation 1.5 mm vertically. The patient should wear it 24 hours a day for the first 4 weeks, then wear it while eating and sleeping for the next 2 weeks, and wear it only while sleeping for the last 2 weeks. Patients must understand that the success of treatment depends on their compliance with the regimen.

Betel quid (BQ) and areca nut (AN) (major BQ ingredient) are group I human carcinogens illustrated by International Agency for Research on Cancer and are closely associated with an elevated risk of oral potentially malignant disorders (OPMDs) and cancers of the oral cavity and pharynx. The primary alkaloid of AN, arecoline, can be metabolized via the monoamine oxidase (MAO) gene by inducing reactive oxygen species (ROS). The aim of this study was to investigate whether the variants of the susceptible candidate MAO genes are associated with OPMDs and oral and pharyngeal cancer. A significant trend of MAO-A mRNA expression was found in in vitro studies. Using paired human tissues, we confirmed the significantly decreased expression of MAO-A and MAO-B in cancerous tissues when compared with adjacent noncancerous tissues. Moreover, we determined that MAO-A single nucleotide polymorphism variants are significantly linked with oral and pharyngeal cancer patients in comparison to OPMDs patients [rs5953210 risk G-allele, odds ratio = 1.76; 95% confidence interval = 1.02-3.01]. In conclusion, we suggested that susceptible MAO family variants associated with oral and pharyngeal cancer may be implicated in the modulation of MAO gene activity associated with ROS.

Based on their mechanical properties and good corrosion resistance, some commercial Ni-Cr stainless steels have been widely applied as biomaterials, including the austenitic 304 stainless steel, the austenitic 316 stainless steel, the duplex 2205 stainless steel, and the ferritic 430 stainless steel. In order to reduce the occurrence of infections resulting from biomaterial implants, instruments, and medical devices, Cu2+ and Ag2+ ions have been added onto biomaterials for increasing the antibacterial properties, but they are known to damage biofilm. The occurrence of nanoparticles can also improve the antibacterial properties of biomaterials through various methods. In this study, we used Escherichia coli and analyzed the microstructures of American Iron and Steel Institute (AISI) 430 stainless steel with a 0.18 mass % N alloy element. During a lower temperature aging, the microstructure of the as-quenched specimen is essentially a ferrite and martensite duplex matrix with some Cr2N precipitates formed. Additionally, the antibacterial properties of the alloy for E. coli ranged from 3% to 60%, consistent with the presence of Cr2N precipitates. When aged at a lower temperature, which resulted in nano-Cr2N precipitation, the specimen possessed the highest antibacterial activity.