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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.

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 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/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.

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.

The purposes of this study were to compare various retainer designs with different design philosophies based on stress breakers and rigid support. The technique of quasi-3-dimensional photoelastic stress analysis was used for this investigation. A photoelastic model was made with individual simulative materials for tooth structure and alveolar bone. The model was fabricated to simulate a mandibular Kennedy class II modification 1 edentulous state with the right 1st premolar as the terminal abutment. Six types of retainers were fabricated for the analysis: a wrought wire clasp; rest, proximal plate, I-bar (RPI) system; conical crown telescopic retainer; rest, bi-proximal plate, I-bar (RPPI) system; ring clasp, and cast circumferential clasp. For each experimental removable partial denture (RPD), a micro-load cell transducer was placed under the denture base to measure the denture base shearing load of the occlusal force. After 18 kg was loaded vertically on the occlusal table of the RPD, photoelastic stress distribution isochromatics and the denture base shearing load were obtained. Results indicated that an unfavorable stress gradient was found with the wrought wire clasp design, with the maximum stress (5.59 kg) being concentrated at the residual ridge while the minimum stress occurred at the abutment. A favorable stress gradient was found with the conical crown telescopic retainer design, with the stress (1.05 kg) being concentrated at the residual ridge. Within the limitations of this experiment, different retainer designs had different effects on the abutment and residual ridge. The retainers designed based on a rigid support philosophy concentrated more stress at the abutment and generated less stress at the residual ridge than those retainers designed with a flexible support. [ABSTRACT FROM AUTHOR]