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A distinctive method for extraction of the bilateral impacted mandibular second molars (MM2s) and moving the bilateral mesioangularly impacted mandibular third molars (MM3s) to the MM2 positions with appropriate occlusion by orthodontic uprighting and protraction was demonstrated in a 24-year-old woman and a 20-year-old woman, respectively. Although the surgical procedures should be performed under general anesthesia, rapid orthodontic treatment after tooth extraction aided in the initial teeth movement of the bilateral MM3s. The proposed treatment could be implemented and completed in 2 years or less. After undergoing the orthodontic treatment, the patient achieved robust bone support no matter with or without bone grafting. With this less technique-sensitive method, the patient still achieved improved posterior occlusion and masticatory function. Oral and maxillofacial surgeons should be consulted before this treatment option was adopted.

Background/purpose: Patients' considerations when choosing an orthodontist are influenced by many factors, including background, ethnicity, and location. Accordingly, this study aimed to identify factors influencing patients’ considerations when selecting an orthodontist in both Malaysia and Taiwan. Materials and methods: In total, 248 dental students from Taipei Medical University and 110 dental students from Manipal University College Malaysia were selected for this study. Participants' considerations when selecting an orthodontist were assessed using a questionnaire survey. The questionnaire collected data regarding participants’ demographic characteristics and their preferences regarding clinical settings, orthodontist attributes, administrative systems, and the influence of social media. The gathered data were analyzed and compared using independent t-test, ANOVA, and chi-squared for both cohorts. Results: The present results revealed significant differences between the Malaysian and Taiwanese participants with several variables, including orthodontist experience, recommendations, pain-free treatment procedures, treatment duration, friendly reception, sources of information about orthodontists, and preferred social media platforms. Notably, among the Taiwanese participants, “person responsible for treatment costs,” was significantly correlated with the orthodontist's age, the orthodontist's work experience, information sources, travel distance, and content posted by orthodontists on social media. By contrast, among the Malaysian participants, this variable was correlated with the work experience of orthodontists. Conclusion: Significant differences were observed between the Malaysian and Taiwanese participants in terms of their considerations when choosing an orthodontist. Participant's gender significantly influenced orthodontist preferences among the Malaysian participants, whereas the individual responsible for treatment costs was identified to be the most crucial factor influencing the Taiwanese participants.

Background/purpose: Many patients pursue attractive smiles, and surgical-orthodontic treatment is a common method. We aimed to analyze the changes in smile parameters after surgical-orthodontic treatment in patients with skeletal Class III pattern and identify factors influencing postoperative outcomes. Materials and methods: This retrospective study comprised 34 patients with skeletal Class III malocclusion and pure mandible prognathism who received surgical-orthodontic treatment. Hard and soft tissue parameters were assessed through lateral cephalometry, and smile esthetics were evaluated through extraoral photography. Postoperative changes in smile parameters and between-parameter correlations were analyzed. Random forest and decision tree deep learning models were used to identify factors influencing postoperative changes. Results: Substantial postoperative changes were observed in the buccal corridor, upper lip height, and smile index. Significant between-sex differences were noted in the upper midline and right chelion. Strong, positive correlations were found between upper lip height and upper lip ratio and between lower lip height and lower lip ratio. By contrast, strong negative correlations were observed between lower teeth exposure and smile index and between interlabial gap and smile index. The highest degrees of postoperative changes were noted in asymmetry-associated smile parameters: lower lip area, interlabial gap, smile index, buccal corridor, and arc ratio. Conclusion: Considerable changes were noted in skeletal, dental, and soft tissue parameters after surgical-orthodontic treatment. However, the changes in smile esthetics were less prominent from the frontal view. As for chin asymmetry, the most to least prominent changes were in the lower lip area, interlabial gap, smile index, buccal corridor, and arc ratio, respectively.

Anterior open bite (AOB), characterized by the lack of vertical overlap between upper and lower anterior teeth, poses a considerable challenge in orthodontics. The condition depends on many factors that combine to render it difficult to achieve post treatment stability. AOB is commonly classified as dental, skeletal, or functional on the basis of the clinical presentation and causative factors. Traditionally, skeletal AOB necessitates surgical intervention, whereas nonsurgical approaches such as extrusion arches and the Multiloop Edgewise Archwire Technique (MEAW) can be employed in more straightforward cases. Functional appliances are reserved for situations in which a patient's growth potential offers the possibility of effectively addressing AOB. This review presents a strategic treatment approach for addressing AOB, taking into account the classification and severity of the condition. The proposed SHE framework describes the use of mini-screws (S) for anchorage and vertical control, encouragement to correct habits (H), and the utilization of extractions and elastics (E). By incorporating extra-radicular mini-screws, AOB closure is achieved through anterior retraction in extraction cases or whole arch distalization of dentition with elastics in non-extraction cases. This framework emphasizes habit correction through a regimen of oral myofunctional therapy (OMT) and habit-correcting appliances to enhance posttreatment stability. This review suggests that nonsurgical correction is viable in the majority of cases, whereas surgical intervention should be reserved for severe cases of skeletal vertical overgrowth or horizontal discrepancies.

This scoping review investigated the evidence on the three-dimensional analysis of a posed smile in adults to discover any research gaps in this research area. Electronic searches of articles written in English were performed using the four databases of Embase, PubMed, Springer, and Web of Science with publications from 2010 to 2023. Reference lists were also manually searched to identify additional studies. The results showed that 13 cross-sectional descriptive studies from Asia, Europe, North and South America met our inclusion criteria. Studies mainly focused on linear and angle measurement for resting and smiling faces and landmark movement from resting to smiling. Most studies conducted analysis of smiles stratified by sex, ethnicity, smile type, dental occlusion, skeletal pattern, and age. Two studies compared smiling with the resting position and one study compared the attractive smiling group with the ordinary group. Our scoping review revealed the insufficiency of some measurement methods, such as those employing area, volume, and soft tissue thickness. Furthermore, few studies were conducted in Asian populations, and comparisons of various smile types, overjet types, horizontal skeletal patterns, and comparisons of smiles between people with untreated normal occlusion and those who had been orthodontically treated were lacking.

Background/purpose: Polyetheretherketone (PEEK) is known for its strength, flexibility, biocompatibility, and potential as a replacement for metals in dental appliances; however, uncertainty remains about the mechanical characteristics and dimensions of PEEK-made orthodontic fixed lingual retainers (FLRs). This study aimed to determine the optimal shape of PEEK-made orthodontic FLRs using the finite element method (FEM) and the three-point bending test (TPBT). Materials and methods: Seventy-five three-dimensional PEEK rod-shaped models were created, which included five thicknesses (0.4, 0.6, 0.8, 1.0, and 1.2 mm), five widths (0.7, 0.9, 1.1, 1.3, and 1.5 mm), and three cross-sectional shapes (rectangular, oval, and hemielliptical). A 0.9-mm (0.036-inch) stainless steel wire (SSW) was used as a control and the FEM was used to determine six optimal dimensions among the PEEK models. The selected models were then fabricated and subjected, along with the SSW, to the experimental TPBT to assess their mechanical responses against lingual and biting pressures. Results: The FEM analysis revealed that Von Mises stresses on the PEEK models decreased with an increase in width and thickness. Six optimal shapes of PEEK models were chosen based on acceptable lingual and biting stresses as well as patient comfort compared to the SSW. Furthermore, PEEK models showed significantly lower deformation during the 3.1-mm deflection test than did the SSW, while no notable differences were observed among different sizes of PEEK models. The hemielliptical PEEK model with a thickness of 1.0 mm and width of 1.5 mm was found to be mechanically robust enough to withstand lingual forces, while none of the PEEK models, including the SSW, were able to resist biting forces. Conclusion: Within the limitations of this in vitro study, PEEK-made orthodontic FLRs with a hemielliptical cross-sectional shape and a thickness-to-width ratio of 1.0:1.5 would be suitable for use as orthodontic FLRs.

Background/purpose: An understanding of self-protection related factors is important for dental infection control. This study aimed to investigate factors associated with personal self-protection in infection control among dental care workers. Materials and methods: A cross-sectional survey with self-report questionnaire was conducted between Jan and Dec, 2018.275 dentists and 298 dental assistants were enrolled from randomly selected dental care settings. Results: Compliance with wearing hair caps, facial masks, and hand washing is not as high as oral masks and gloves (over 90%). For dentists, the level of clinical setting (aOR = 3.1, P

Abstract Background: /purpose: Several factors such as identity, income, and age potentially associated with smile perceptions. This study aimed to identify the factors affecting the smile esthetic perception in different identities (layperson, general dentist and orthodontist) and to detect the extent of their association with smile perception. Materials and methods: Extraoral photographs in frontal, lateral, and three-quarter views were shot and adjusted on Adobe Photoshop into 95 smile photographs with different smile patterns. Based on these photographs, the investigators were asked to fill the online questionnaire. Pearson chi-square test and logistic regression were used for statistical analyses. Results: Identity, gender, age, and treatment experience were noted to affect smile esthetic perception. In addition, the perception of smile esthetics was significantly different among frontal, lateral, and three-quarters views regarding the arc ratio, most posterior teeth exposure, upper teeth exposure, and lower teeth exposure. Conclusion: Identity, gender, age, and treatment experience influence the smile esthetics perception, with a significant difference in the results of the esthetic perception based on the 3 smile views. Of all demographic factors, identity had a strong relation to the perception of smile attractiveness. Nevertheless, additional studies are needed to realize how the demographic factors influence people's perception of smile esthetics, particularly in the three-quarter and lateral views.

Background: —Spontaneous intracranial hemorrhage (ICH) has high fatality while has few proven treatments. We aim at investigating the association between dental scaling (DS) and the risk of ICH. Methods: —In this cohort study, two cohorts were matched by propensity score based on potential confounders. Data from ICH between January 2008 and December 2014 in Taiwan were analyzed. The subjects underwent DS at least 6 times between January 1, 2002, and December 31, 2007, while the matched controls did not undergo any DS during the same period. Cumulative incidences and hazard ratios (HRs) were calculated after adjusting for competing confounders. Results: —Each cohort consisted of 681,126 subjects. Compared with the non-DS cohort, the regular-DS cohort had a significantly lower incidence of ICH (0.8% vs 1.2%; P

Background/purpose: Treatment of incisors‘ agenesis is challenging that arouses orthodontists’ interests. The purpose of this study was to compare the craniofacial pattern of individuals with or without congenitally missing mandibular incisors. Materials and methods: This retrospective study included patients receiving orthodontic consultation between 1999 and 2019 at the Orthodontic Division of the Dental Department of Taipei Medical University Hospital. Cephalometric measurements were obtained through manual tracing and by using computer software. A total of 31 measurements were obtained to evaluate skeletal, dental and soft tissues, and chin morphology. A multivariate analysis of covariance, analysis of covariance, and Scheffé’s post hoc tests were used to analyze the differences among a group of patients with one congenitally missing mandibular incisor (M1), a group of patients with two congenitally missing mandibular incisors (M2), and the control group. Student's t-test was used to analyze the differences between the M1 or M2 group and the control group. Significance was set at P

Background/purpose: The postgraduate year dentist training program (PGYD) officially implemented in 2010. This study aimed to assess PGYD trainees’ subjective satisfaction perception and objective competence performance according to different training institutions (either dental clinics or hospitals). Materials and methods: A nationwide cross-sectional survey was conducted in 2018. Subjective satisfaction questionnaires from 222 PGYD trainees and 166 PGYD trainees’ scores of objective structured clinical examinations (OSCEs) were collected for analysis. The t-test and logistic regression were used to compare differences between two groups. Results: In subjective satisfaction, PGYD trainees in hospitals revealed less positive perceptions on teachers (odds ratios [ORs] range: 0.33–0.7) and on training plans and auxiliary facilities (ORs range: 0.23–0.69), but they had more opportunities to attend and present at professional meetings than those in clinics. In PGYD trainees’ opinion, the optimal training period allocation was 25% in hospitals and 75% in clinics. Overall, trainees in hospitals had better OSCE scores than those in clinics (OR [95% confidence interval, CI]: 3.12 [1.68–5.79]), except for the item of “the relation between physical condition and dental treatment outcome” (0.3 [0.1–0.97]). Conclusion: PGYD trainees in dental clinics have more positive perceptions on teachers and on training plans and auxiliary facilities, but PGYD trainees in hospitals have better OSCE scores. PGYD trainees prefer to be trained in clinics for a better connection with future careers, while hospitals can offer better training for PGYD trainees to become independent dentists because they have better training environment and more educational resources.

Abstract Background This study seeks to elucidate the impact of COVID-19 on knowledge, attitude, and infection control behaviors among dentists. Methods Changes in knowledge, attitude, and infection control behaviors reported in 2020 (COVID-19 period) were compared to the historical control of the non-COVID-19 period in 2018. A proportional random sampling method was used to select the study samples from 400 dental institutions. The response rate was 69% in 2018 and 62.8% in 2020. A total of 276 dentists in 2018 and 251 dentists in 2020 responded to this questionnaire. Multiple logistic regression was used to assess the associations between factors and recommended infection control practices. Results High rates of correct COVID-19 knowledge (94.76%), fears of being infected with the virus (94%) and use of personal protective equipment (mask, glove and protection gown; 95%) were reported. We found that knowledge regarding environmental infection control, HIV transmission, and the window of HIV transmission were significantly higher in the post-COVID-19 period compared with the pre-COVID-19 period. High compliance rates of wearing mask, gloves and protection were reported. The number of dentists wearing a hair cap and a protective eye mask/face shield during the pandemic significantly increased compared with that noted before the COVID-19 pandemic. Factors associated with the use of a hair cap and an eye mask/face shield differed between the pre- and post-COVID-19 periods. The factors associated with compliance regarding environment infection control also differed between the pre- and post-COVID-19 periods. Conclusion The significant impact of COVID-19 on the knowledge, attitude, and infection control behaviors among dental care workers was observed in the current study. In particular, the use of hair caps and protective eye mask or face shields as well as environmental disinfection protocols has significantly improved. Trial registration TMU-JIRB: N201804006.

Abstract Background Dental students have encountered changes in the teaching format amid the SARS CoV-2 pandemic. This study aims to evaluate the attitudes of dental students of one medical university toward online courses and compare them with those of non-dental students amid the SARS CoV-2 pandemic. Methods A cross-sectional survey with a self-report online questionnaire was conducted at the medical university in May 2020 in Taipei. Students from the School of Dentistry, School of Dental Technology, and School of Oral Hygiene Study were enrolled in our survey. Results In total, 473 students responded to the survey, 318 (67.2%) of whom were dental students. Overall, 366 (77%) students agreed with the change to online learning. Only 10.4% of students thought that dental professional courses with a laboratory format could be changed to online courses. Dental students were significantly more worried than non-dental students about being infected with COVID-19 and about the COVID-19 pandemic continuing. Conclusions In conclusion, changing to online learning seems to be perceived as feasible by students. However, more discussion about changing dental professional courses with a laboratory format to online courses considering the attitudes from students is needed.

Background/purpose: The purposes of this study were to develop smile measurements for lateral and oblique view photographs to help in orthodontic analysis and treatment planning, to quantitatively evaluate the relationship between smile esthetics and different types of malocclusion using lateral and oblique view photographs, to identify the cephalometric factors affecting smile measurements. Materials and methods: Patients who came to orthodontic department of a university hospital from 2014 to 2017 and met the inclusion criteria were included and divided into three groups according to Angle's classification. Thirteen variables were measured for cephalometric analysis. Twenty-one variables were developed and measured on pretreatment photographs for lateral and oblique smile analysis. ANOVA and Scheffe post hoc test were used to compare cephalometric and smile variables among three groups. Multiple linear regression analysis was performed to identify cephalometric factors affecting smile measurements. Results: Three-hundred and ninety patients (287 females, 103 males) with mean age of 24.5 ± 7.6 years reached the criteria. All cephalometric variables differed significantly among three groups. Except for maxillary teeth exposure number, visible maxillary width, and lip thickness ratio, all smile variables differed significantly. Smile characteristics had significant correlation with some cephalometric measurements. Conclusion: Smile patterns on the lateral and oblique view photographs can be affected by different types of malocclusion. Therefore, we suggest to include lateral and oblique smile view photographs in the data collection for orthodontic treatment planning.

In current study, we have investigated the anti-oral cancer effects of developed functional beverage, which integrates fucoidan complex (FC) with natural/organic ingredients including vegetable juice (V), mulberry (M) and wheatgrass (W), designated as VMW-FC cocktail. FC has been recognized as functional food with nutraceutical characteristics, other cocktail components are known to individually contain luxuriant bioactive factors including sulfated polysaccharides and polyphenols etc., exerting various curative impacts. Our results demonstrated that VMW-FC significantly inhibited oral cancer proliferation in a dose- and time-dependent manner. It also retarded cell cycle regulators (CDKs and cyclins) and upregulated cyclin-dependent kinase inhibitor p21. Additionally, VMW-FC suppressed cell migration along with inhibited EMT markers. Further, VMW-FC significantly attenuated xenograft tumor growth in NOD-SCID mice without further adverse effects. Conclusively, VMW-FC strongly inhibits oral cancer through inducing apoptosis, G2/M cell cycle arrest and reducing migration-related EMT markers, which may be primarily attributed to sulfated polysaccharides in beverage cocktail.

Carbon monoxide (CO) is now well recognized a pivotal endogenous signaling molecule in mammalian lives. The proof-of-concept employing chemical carriers of exogenous CO as prodrugs for CO release, also known as CO-releasing molecules (CO-RMs), has been appreciated. The major advantage of CO-RMs is that they are able to deliver CO to the target sites in a controlled manner. There is an increasing body of experimental studies suggesting the therapeutic potentials of CO and CO-RMs in different cancer models. This review firstly presents a short but crucial view concerning the characteristics of CO and CO-RMs. Then, the anticancer activities of CO-RMs that target many cancer hallmarks, mainly proliferation, apoptosis, angiogenesis, and invasion and metastasis, are discussed. However, their anticancer activities are varying and cell-type specific. The aerobic metabolism of molecular oxygen inevitably generates various oxygen-containing reactive metabolites termed reactive oxygen species (ROS) which play important roles in both physiology and pathophysiology. Although ROS act as a double-edged sword in cancer, both sides of which may potentially have been exploited for therapeutic benefits. The main focus of the present review is thus to identify the possible signaling network by which CO-RMs can exert their anticancer actions, where ROS play the central role. Another important issue concerning the potential effect of CO-RMs on the aerobic glycolysis (the Warburg effect) which is a feature of cancer metabolic reprogramming is given before the conclusion with future prospects on the challenges of developing CO-RMs into clinically pharmaceutical candidates in cancer therapy.

Objective To investigate whether overbite affects smile esthetics. Methods This study involved 106 patients with complete pretreatment records. Lateral cephalometric tracings were used to measure hard tissue variables. Frontal smile and upper occlusal photographs were used to measure nine smile esthetic variables: arc ratio, number of teeth, upper incisor exposure, upper midline, buccal corridor ratio, smile index, archform index, lower teeth exposure, and interlabial gap. The patients were classified into three groups according to their overbites (B1: 0–4 mm, B2: >4 mm, and B3:

Background/purpose: Patient safety is a major healthcare challenge. Due to a lack of safety culture knowledge among dental professionals, our objectives were to measure the level of patient safety culture using the Safety Attitude Questionnaire in Chinese (SAQ-C) and identify factors associated with positive attitudes toward patient safety. Materials and methods: A nationwide cross-sectional survey was conducted within dentistry departments of 20 hospitals and in 40 dental clinics, from which were randomly chosen. The survey (SAQ-C) comprised of 32 items and reflects five dimensions of patient safety culture. The second section collects demographic information that supposedly affects attitudes toward patient safety. Logistic regression analyses were used to identify factors that supposedly influenced positive attitudes toward patient safety. Results: Mean SAQ-C scores were significantly higher in respondents who were male, older, dentists, supervisors, and working in clinics. Positive attitudes toward patient safety were found in 172 participants (55.7%). Multivariate analyses revealed age and place of work are significantly associated with positive safety attitudes. A limitation of this study is that the association between SAQ-C scores and patient outcomes could not be examined. Conclusion: With a lack of research in the dental field, our study provides important information on patient safety attitudes for dental healthcare workers. Results from this study present the current status of patient safety culture and help raise awareness of it. Most notably, the study identified several factors associated with positive attitudes toward patient safety. The information can be used to improve patient safety in the future. Keywords: Cross-sectional study, Dental healthcare workers, Nationwide survey, Patient safety, Risk factors

Besides inhalation, a few studies have indicated that the uptake of nicotine through air or clothing may be a significant pathway of its exposure among passive smokers. Nicotine is well known to exert various physiological impacts, including stimulating sympathetic nervous system, causing vascular disturbances, and inducing cell death. Therefore, we aimed to establish whether exposure of nicotine could induce articular cartilage degeneration in a mouse model of osteoarthritis (OA). We specifically assessed dose-dependent effect of nicotine in vitro to mimic its accumulation. Further, during the in vivo studies, mice subcutaneously administered with nicotine was examined for OA-associated pathologic changes. We found that nicotine significantly suppressed chondrocytes and chondrogenic markers (Sox, Col II, and aggrecan). Nicotine-treated mice also showed altered knee joint ultrastructure with reduced Col II and proteoglycans. After corroborating nicotine-induced OA characteristics, we treated this pathologic condition through employing platelet-derived biomaterial (PDB)-based regenerative therapy. The PDB significantly suppressed OA-like pathophysiological characteristics by 4 weeks. The mechanistic insight underlying this therapy demonstrated that PDB significantly restored levels of insulin-like growth factor 1 (IGF-1) signaling pathway proteins, especially pIGF-1 R, pAKT, and IRS-1, regulating extracellular matrix synthesis by chondrocytes. Taken together, the PDB exerts regenerative and reparative activities in nicotine-mediated initiation and progression of OA, through modulating IGF-1/AKT/IRS-1 signaling axis.

Background/purpose: Whether third molars contribute to or aggravate relapse, particularly in the mandibular dental arch, after orthodontic treatment remains controversial. Orthodontic clinicians vary widely in their practice regarding prophylactic third molar removal after orthodontic treatment. The present study systematically reviewed and meta-analyzed the available literature, and assessed the impact of third molar removal on the relapse of mandibular dental arch alignment after orthodontic treatment. Materials and methods: Relevant literature was searched on online databases, namely Pubmed, Embase, and Cochrane. Outcomes of post-orthodontic mandibular relapse were evaluated in terms of the Little's irregularity index, intermolar width, and arch length. Statistical analysis was conducted using the Review Manager software (Version 5.3, The Cochrane Collaboration, Oxford, England). Results: Our initial search strategy yielded 360 citations, of which three retrospective studies were selected. The Little's irregularity index (weighted mean difference = 0.80, 95% confidence interval = 0.13–1.47, P = 0.02) differed significantly between the erupted third molar extraction group and agenesis third molar group; whereas the arch length and intermolar width did not. No outcome differed significantly between the impacted third molar extraction group and agenesis third molar group. Conclusion: Removal of the mandibular third molars is recommended for alleviating or preventing long-term incisor irregularity. Keywords: little's irregularity index, post-orthodontic mandibular relapse, prophylactic third molar removal, third molars

Background/purpose: Many factors, including economic, psychosocial statuses and ethnicity, affect patients' decision to seek orthodontic treatment. The present study compared orthodontic patients' motivation, attitude and the factors affecting this motivation in Taiwanese and Thai patients. We investigated the association between the aforementioned variables and patient characteristics. Materials and methods: We enrolled 250 Thai and 250 Taiwanese patients (age â¥Â 20 years) from Sunprasitthiprasong and Taipei Medical University Hospitals, respectively, by using self-administered questionnaires. Demographic characteristics were analyzed using Pearson's chi-square test, patients' motivation, attitude and the factors affecting this motivation were analyzed using the sample t-test. The association among the variables was investigated by multiple regression analysis. Results: In both hospitals, the main motivation for seeking orthodontic treatment was esthetic concerns; the patients believed that treatment could make them more beautiful. Taiwanese and Thai patients rejected treatment because of high treatment costs and long treatment periods, respectively. A significant association was observed between household income and Thai patients' motivation (pÂ

Background/purpose: Anterior crossbite correction is common in orthodontic treatment; however, few studies have discussed the change with cephalometric measurements. The purpose of this study was to evaluate the dentofacial changes in anterior crossbite correction by using an upper lingual arch with finger springs. Materials and methods: This retrospective study included 30 patients (13 female and 17 male). According to the number of crossbite teeth, the patients were divided into three groups. We used paired t test, Kruskal–Wallis test, Mann–Whitney U test, and multiple regression analysis to perform statistical analysis. Results: According to overall treatment changes, the dental changes included overjet increase, overbite decrease, upper incisor proclination, lower incisor retroclination and intrusion, upper molar distal tipping with extrusion, and lower molar intrusion. These dental changes resulted in clockwise mandibular rotation and lip position change. Anterior crossbite correction did not require increasing bite appliances. According to multiple regression analysis, the change in overjet was associated with the position of the upper and lower incisor crown tips. The mean rate of upper incisor movement in the horizontal direction was 2.5 mm/mo. The treatment duration exhibited no significant difference among the three groups. Conclusion: Lingual arch with finger springs was effective in anterior crossbite correction regardless of the number of crossbite teeth.

Objective This study aimed to evaluate compliance with guidelines on hand hygiene by examining five handwashing categories in postgraduate year (PGY) dentists at a university teaching hospital and to evaluate the accuracy rates of handwashing. Methods Through direct observation, trained PGY dentists were monitored throughout their daily care routine of before contact with patients, before using an instrument, after contact with patients, upon direct exposure to patients’ fluids, and while touching the patients’ surrounding area. Hand hygiene opportunities were considered complete in each category. A total of 16,597 hand hygiene opportunities across 37 individuals were observed from July to October 2012 and from September to October 2013. Results The overall handwashing compliance rate was 34.7%. The handwashing compliance rate was higher during work in oral surgery services (92.8%) than during work in general clinical practice (34.2%). The accuracy rate of handwashing was also higher during work in oral surgery services (87.5%) than during work in general clinical practice (51.0%). Similar results were obtained across all five handwashing categories. Conclusions Handwashing compliance and accuracy rates are low in PGY dentists. More education and continuous monitoring are suggested to improve handwashing compliance, as well as the correct handwashing procedures for dentists.

Background/purpose: Smile esthetics is a critical factor for evaluating orthodontic treatment outcomes. The effects of tooth extraction on smile esthetics and buccal corridor remain controversial and have not been adequately investigated. Therefore, in this systematic review and meta-analysis, we evaluated the aforementioned effects. Materials and methods: We searched clinical studies held in PubMed, MEDLINE, Embase, and the Cochrane Library up to May 2015, with no restriction. Study selection and data extraction were conducted by two reviewers independently. A random-effects model was used for conducting a meta-analysis to assess the mean difference between the esthetic score and the buccal corridor ratio of extraction and nonextraction groups. Results: Six eligible studies were included in this meta-analysis. No significant difference was observed in the esthetic score and the buccal corridor ratio between extraction and nonextraction groups. Conclusion: Tooth extraction does not affect smile esthetics or buccal corridor. However, additional detailed, large-scale, double-blinded, and randomized controlled trials are required for further evaluation.

Studies examining the effect of operator experience on the accuracy of static guided implant surgery have used postoperative computed tomography (CT) images to measure the error, with inconsistent results. The purpose of this study was to try to clarify this issue by using a measurement method based on the postoperative optical scan. Thirty dentists were divided into an experienced group and an inexperienced group. On a partially edentulous mandibular model in the manikin head, each dentist placed three implants via the stereolithographic (SLA) surgical guide. The implant positions were identified by a desktop scanner and compared with the planned positions using a metrology software program. No statistically significant differences were observed for any of the measured positional and angular deviations of the three implant sites between experienced and inexperienced operators (p > 0.01). All the mean values of deviations of the inexperienced group, except the depth deviation, were less than the experienced group. Implants inserted by dentists under 40 years old had significantly better accuracy than senior doctors in the global deviation at implant apex (p = 0.006). Within the limits of this study, we concluded that operator experience is not a critical factor in achieving the accuracy of guided implant surgery via the tooth-supported SLA surgical guide. Large deviations could occur even with the aid of the SLA surgical guide, and care must be taken to avoid errors for both experienced and inexperienced operators.

Background/purpose: This study attempted to understand the spreading characteristics of airborne bacterial contaminants during dental scaling treatment. Materials and methods: Bacterial aerosols were collected with gelatin filters, in a single-chair clinic during ultrasonic scaling treatments on two patients with periodontitis. Results: The results showed that bacterial aerosols contamination could spread a horizontal distance of 100 cm and a vertical distance of 50 cm from a patient’s oral cavity, and remain airborne suspended for 20 minutes. Conclusion: Proper environmental and personal infection control measures, including isolation, ventilation, and full-cover facial shield, are recommended to diminish the contaminating risk in dental clinics.