Automated facial landmark measurement using machine learning: A feasibility study.

STATEMENT OF PROBLEM: Information regarding facial landmark measurement using machine learning (ML) techniques in prosthodontics is lacking. PURPOSE: The objective of this study was to evaluate and compare the reliability, validity, and accuracy of facial anthropological measurements using both manual and ML landmark detection techniques. MATERIAL AND METHODS: Two-dimensional (2D) frontal full-face photographs of 50 men and 50 women were made. The interpupillary width (IPW), interlateral canthus width (LCW), intermedial canthus width (MCW), interalar width (IAW), and intercommissural width (ICW) were measured on 2D digital images using manual and ML methods. The automated measurements were recorded using a programming language (Python), and a convolutional neural network (CNN) model was trained to detect human facial landmarks. The obtained data from the manual and ML methods were analyzed using intraclass correlation coefficients (ICCs), the paired sample t test, Bland-Altman plots, and the Pearson correlation analysis (α=.05). RESULTS: Intrarater and interrater reliability values were greater than 0.90, indicating excellent reliability. The mean difference between the manual and ML measurements of IPW, MCW, IAW, and ICW was 0.02 mm, while it was 0.01 mm for LCW. No statistically significant differences were found between the measurements obtained by the manual and ML methods (P>.05). Highly significant positive correlations (P<.001) were obtained between the results of the manual and ML methods: (r=0.996[IPW], r=0.977[LCW], r=0.944[MCW], r=0.965[IAW], and r=0.997[ICW]). CONCLUSIONS: In the field of prosthodontics, the use of ML methods provides a reliable alternative to manual digital techniques for carrying out facial anthropometric measurements.

Artificial Intelligence (AI)-driven dental education: Exploring the role of chatbots in a clinical learning environment.

STATEMENT OF PROBLEM: Despite their widespread use in various educational contexts, the integration of chatbots into dental clinical education has not been thoroughly investigated. The noted discrepancy signifies a lack of understanding of how chatbots could enhance the personalized and interactive learning experiences of predoctoral dental students. PURPOSE: The purpose of this study was to evaluate the awareness and perceptions of artificial intelligence (AI) technology, interaction experiences, and concerns about a custom-developed chatbot (CB) intervention in the clinical education of predoctoral dental students at the University of Illinois Chicago, College of Dentistry (UIC-COD) compared with the traditional Blackboard (BB) online platform. MATERIAL AND METHODS: Eligible participants (n=86) providing verbal consent were allocated via the random block method into BB (n=43) and CB (n=43) groups and asked to engage with their designated platforms for 10 to 15 minutes by focusing on clinical inquiries in a predoctoral implant clinic and supported by a list of 35 typical questions. After the interaction, participants responded on a 5-point Likert scale to a 19-item survey probing AI awareness, platform engagement, and technological concerns. Survey data were anonymized and analyzed using descriptive, inferential statistics and nonparametric Mann-Whitney U tests to compare interventions. The Bonferroni correction for multiple comparisons was performed (α=.0045). RESULTS: Neither the BB or CB group showed any difference in their awareness and perception of AI technology. The CB group demonstrated improved timeliness (P<.001), more interaction (P<.001), reduced faculty workload (P=.001), enhanced receptiveness (P=.002), and less anxiety (P<.001) and was more satisfied (P<.001) when compared with the BB group. However, concerns regarding the potential for incorrect information (P=.003) were more pronounced in the CB group. CONCLUSIONS: The integration of chatbot technology into dental clinical education significantly enhanced learning and student engagement, highlighting the potential for future technological enrichment of the educational landscape.

Effect of various surface treatment methods on shear bond strength between acrylic denture teeth and thermoplastic nylon denture base.

PURPOSE: To evaluate the effect of mechanical, chemical, and mechanical-chemical surface treatment methods on shear bond strength between acrylic denture teeth and thermoplastic nylon denture base. MATERIALS AND METHODS: Maxillary central incisor teeth were treated with five different surface treatment methods: mechanical (sandblasting, T-shape diatoric holes), chemical (5% acetic acid solution, bonding agent), and mechanical-chemical (sandblasting + bonding agent) were embedded in thermoplastic nylon denture base (n = 10). A universal testing machine with a crosshead speed of 0.5 mm per minute was used to test the shear bond strength. Data obtained were statistically evaluated using one-way ANOVA and followed with Tukey post hoc test (α = 0.05) RESULTS: T-shaped diatoric holes exhibited significantly higher shear bond strength among the surface treatment groups, followed by sandblasting + bonding agent, sandblasting, bonding agent, and the acetic acid group (p < 0.001) CONCLUSION: T-shaped diatoric holes as a mechanical surface treatment showed higher shear bond strength than other methods.

Early Predicting Tribocorrosion Rate of Dental Implant Titanium Materials Using Random Forest Machine Learning Models.

Early detection and prediction of bio-tribocorrosion can avert unexpected damage that may lead to secondary revision surgery and associated risks of implantable devices. Therefore, this study sought to develop a state-of-the-art prediction technique leveraging machine learning(ML) models to classify and predict the possibility of mechanical degradation in dental implant materials. Key features considered in the study involving pure titanium and titanium-zirconium (zirconium = 5, 10, and 15 in wt%) alloys include corrosion potential, acoustic emission(AE) absolute energy, hardness, and weight-loss estimates. ML prototype models deployed confirms its suitability in tribocorrosion prediction with an accuracy above 90%. Proposed system can evolve as a continuous structural-health monitoring as well as a reliable predictive modeling technique for dental implant monitoring.

Evaluating augmented reality e-typodont to improve a patient's dental implant health literacy.

STATEMENT OF PROBLEM: Information regarding dental implants can be difficult to understand for participants. Improving patients' dental implant health literacy remains a challenging process. PURPOSE: The purpose of this clinical study was to develop and evaluate patients' understanding of the implant treatment procedure, components, and sequences using traditional typodont and augmented reality (AR) applications (e-typodont), with the goal of improving their oral health literacy. MATERIAL AND METHODS: Participants who had sought dental implant treatment at the group practice and implant clinic at the University of Illinois Chicago (UIC) College of Dentistry were invited to enroll in this study. Participants were asked to fill out the first questionnaire (Q1) assessing their understanding of implant treatment procedures, components, and sequences. The participants were randomly exposed to 1 of the 2 modes of delivering education, typodont or AR e-typodont. The participants were asked to complete the additional 2 questionnaires (Q2 and Q3), and the posttest questionnaire (Q1) to re-evaluate their understanding of the implant treatment procedure, components, and sequences. All data were entered and coded into a spreadsheet. Descriptive (mean) and statistical (Wilcoxon Signed Ranks and Mann-Whitney U test) analyses were used (α=.05). RESULTS: Both interventions significantly increased participants' understanding of implant treatments (typodont: P=.004; e-typodont: P<.001), implant components (typodont: P=.003; e-typodont: P<.001), and implant treatment sequences (typodont: P=.001; e-typodont: P<.001). The e-typodont group significantly improved participants' understanding of implant treatments (P=.006), implant components (P=.023), and implant treatment sequences (P=.008) compared with the typodont group. Participants perceived the e-typodont mode of delivery to be significantly more interesting (P=.002), interactive (P=.008), educational (P=.002), user-friendly (P=.016), and "Wow" (P=.002) compared with the traditional typodont mode of delivery. CONCLUSIONS: Both interventions improved participants' understanding of implant treatment procedures, components, and sequences. The e-typodont showed better improvement in participants' understanding of dental implants compared with the traditional typodont.

Level of evidence and characteristics of clinical studies published in leading prosthodontics journals.

STATEMENT OF PROBLEM: Data on the level of evidence and the characteristics of studies published in peer-reviewed prosthodontic journals are lacking. PURPOSE: The purpose of this study was to investigate the characteristics and level of evidence (LOE) scores of studies published in 3 leading peer-reviewed prosthodontic journals. MATERIAL AND METHODS: Clinical studies published in the Journal of Prosthetic Dentistry (JPD), the Journal of Prosthodontics (JP), and the International Journal of Prosthodontics (IJP) in 2013 and 2020 were included in the analysis. Abstracts, letters to the editor, book reviews, and animal and laboratory studies were excluded from the investigation. For each study, design, type and LOE scores (Levels 1 to 5), publication year, impact factor (IF) of the journals, geographic origins of the first and corresponding authors, and funding status were recorded. Level 1 and Level 2 were defined as high evidence (HE), and Level 3, Level 4, and Level 5 were defined as low evidence (LE). Descriptive statistics and logistic regression analysis were performed (α=.05). RESULTS: Among the 439 studies included in the analysis, the proportion of HE and LE studies was 14.1% and 85.9%, respectively. According to univariate and multivariate analysis results, year of publication (P=.010 and P=.029), geographic origin of the corresponding author (P<.001), and funding status (P<.001 and P=.002) were significantly associated with the LOE of a study. However, the journal IF was not associated with LOE (P=.328). CONCLUSIONS: Although the number of HE studies in 3 leading prosthodontic journals has increased over time, the total number was still limited compared with LE studies. A further improvement in the overall LOE of clinical studies in prosthodontics is needed.

Predictability of single versus double-barrel vascularized fibula flaps and dental implants in mandibular reconstructions: A systematic review and meta-analysis of prospective studies.

STATEMENT OF PROBLEM: Patients with vascularized bone flaps from the fibula have reduced bone height, in which case a higher prosthetic abutment is needed for their implant-supported prosthesis. Although the double-flap technique seems promising, systematic reviews and meta-analyses of prospective studies are lacking. PURPOSE: The purpose of this systematic review and meta-analysis was to evaluate the grafted areas of single barrel fibular flaps (SBFF) and double-barrel fibular flaps (DBFF) by considering failure rates, dental implant complications, and bone union at the osteotomy sites. MATERIAL AND METHODS: A systematic review and meta-analysis was performed in accordance with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement, population, intervention, control, and outcomes (PICO) question, and the National Health and Medical Research Council scales. The event rate of complications and failures was calculated with a confidence interval (CI) of 95%. RESULTS: A total of 13 prospective studies with 441 participants and 330 graft sites were identified. A total of 235 participants had SBFF with 445 implants, and 95 had DBFF with 164 implants. The overall combined graft failure rates were 4.2% for SBFF and 3.2% for DBFF. The complication rate was 10% for SBFF and 1.9% for DBFF. Implant failure was at 4.7% in the SBFF group and 3.4% in the DBFF group. CONCLUSIONS: Complication rates and implant failures were similar for SBFF and DBFF. Therefore, for long-term oral rehabilitation, both SBFF and DBFF are suitable procedures for mandibular reconstruction.

Profile of prosthodontics program directors in North America.

PURPOSE: To develop a current profile of prosthodontics program directors (PPDs) in United States dental schools and describe the current challenges and responsibilities of those serving in the position and assess the professional needs of the program directors (PDs) to better support them in their roles. MATERIALS AND METHODS: A survey was sent to 51 participants who were identified as PPDs in North America via Qualtrics in 2019 to assess the professional needs of PDs to better support their roles. The survey consisted of 29 items organized into six sections: (1) demographic information; (2) hours and time spent in various areas of the job; (3) greatest challenges; (4) perceived importance of specific competencies; (5) opinions on the greatest rewards of the position; (6) their needs for support from the American College of Prosthodontists and advice for the future PD. RESULTS: The response rate for this survey was 88.3%. Of the 45 respondents, the majority were white/non-Hispanic, followed by Asian/Pacific Islanders. The two largest and equal numbers of participants who worked for more than 10 years and between 1 and 3 years were observed with approximately 29% each, and PDs who worked less than a year occupied the least amount. Overall, 34% of PDs are on the tenure track and 80% of those are tenured. Teaching and clinical services took away the greatest time with approximately 42% and 22.1%, respectively. Thirty-five (78%) PDs listed the greatest challenge they encountered was the workload of the role. Skills listed in leadership and personnel competencies were all rated more important than most of the skills listed in management. CONCLUSIONS: There is a wide gender gap and a lack of racial diversity among the PPDs. The biggest challenge faced by them is the amount of workload followed by budget and fiscal constraints. And for their improved efficiency, they gave emphasis on learning time management and continuous clinical training of newer advances.

Is atomic layer deposition of silver possible on N95 masks?

Due to the COVID19 outbreak, there has been increasing interest in tailoring, modifying and improving conventional personal protective equipment to increase their service life and make them more effective against viruses and bacteria. Here, atomic layer deposition (ALD) was used to functionalize the filter of N95 mask with nano-islands of silver. X-ray photoelectron spectroscopy and x-ray absorption fine structure were used for ALD silver characterization; microbiological assay was conducted to study the effectiveness of the deposited silver against the air-borne pathogen Staphylococcus aureus (S. aureus). Results showed that silver ALD successfully functionalized the N95 mask at 90 and 120 °C for two different numbers of ALD cycles (1100 and 1500 cycles). The deposited silver nano-islands were stable on the N95 filter media against washing. The leaching of silver nano-islands was studied using inductively coupled plasma mass spectrometry of phosphate-buffered saline solution after soaking the mask in it over predetermined times. <9% of Ag was removed after a maximum time of 4 h that was investigated. Antimicrobial tests showed that for samples functionalized with 1100 ALD cycles of Ag, 76% reduction in S. aureus colony-forming units content was observed after 24 h of biofilm development on the mask surfaces.

Attachment systems for mandibular implant-supported overdentures: A systematic review and meta-analysis of randomized controlled trials.

STATEMENT OF PROBLEM: Although mandibular implant-supported overdentures have been highly recommended as a treatment option, a consensus on the type of attachment systems that can be used to increase implant and prostheses survivability is lacking. PURPOSE: The purpose of this systematic review and meta-analysis was to compare different types of attachments for retention by investigating outcome measures such as implant and prosthesis survival rates and biological and prosthesis complications in participants with a mandibular implant-supported overdenture. MATERIAL AND METHODS: The search was performed in the PubMed, Cochrane, Embase, and Scopus databases by following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria and registered with the International Prospective Register of Systematic Reviews (CRD42021253566). An analysis of association was conducted between different attachment systems and implant and overdenture survival rates in randomized controlled clinical trials. RESULTS: The initial search indicated 477 studies, of which 25 randomized controlled trials (RCTs) were included for analysis. A total of 2154 implants and 737 overdentures were analyzed in the meta-analysis. The main results indicated the failure rate for dental implants to be 2.0% (95% confidence interval [CI], 1.3 to 3.2) and overdentures 4.2% (95% CI, 1.6 to 10.5), respectively. With regard to different attachment systems, a similar failure rate was identified with bar-type retention (7.7% to 95% CI, 3.0 to 18.1), magnetic retention systems (7.6% to 95% CI, 2.2 to 22.7), and ball-type retention (6.8% to 95% CI, 3.0 to 14.3). No significant difference was found in biological complications for splinted and unsplinted implant overdentures (P=.902). Regarding prosthetic complications, the most favorable groups were LOCATOR attachments followed by telescopic and Conus, bar, and ball attachments. Magnet attachments had higher prosthetic complications (7.4 times) than the other attachments. CONCLUSIONS: Implants and implant-supported mandibular overdentures showed a high survival rate irrespective of the attachment system used. Splinting implants did not significantly affect the rate of biological complications. Prosthetic complications were most common for magnet and least common for LOCATOR attachments.

Impact of COVID-19 on Malaysian dental students' physical, mental, financial and academic concerns.

BACKGROUND: The coronavirus disease 2019 (COVID-19) caused by a novel coronavirus (SARS-CoV-2) has gained worldwide attention and proved to hold an impact to humankind in all aspects of life. Dental students' performances may indirectly be affected following the preventive measures in containing the disease. This study aims to evaluate the impact of COVID-19 pandemic on physical, mental, financial health and academic concern among dental students in Malaysia. METHODS: The current research implemented a cross sectional study among dental students in Malaysia. Assessment of the impact of COVID-19 on dental education was done by the distribution of a set of online survey consisting of 28 questions to dental students (n = 353) from public and private universities in Malaysia. The questionnaires include sociodemographic backgrounds and assessment on the mental health, financial health, physical health and academic concern. Kruskal Wallis test and Mann-Whitney U test were used to analyse the impact of COVID-19 to these 4 domains according to sociodemographic background. RESULTS: A total number of 353 respondents was recorded and 76.2% comprised of female. 59.7% were clinical students and 40.3% were preclinical students. Most of students were concerned about their own emotional health, financial concern, physical wellbeing, in which Year 3 students were found to be more concerned about their mental and financial health concern. CONCLUSIONS: COVID-19 pandemic had indeed significantly affected Malaysian dental students mainly due to fear of the quality of online learning and the amount of clinical skills acquired. Therefore, it is important to identify dental stressors and lessen the impact of COVID-19 to dental students.

Dentin Matrix Protein 1 on Titanium Surface Facilitates Osteogenic Differentiation of Stem Cells.

Dentin matrix protein 1 (DMP1) contains a large number of acidic domains, multiple phosphorylation sites, a functional arginine-glycine-aspartate (RGD) motif, and a DNA binding domain, and has been shown to play essential regulatory function in dentin and bone mineralization. DMP1 could also orchestrate bone matrix formation, but the ability of DMP1 on Ti to human mesenchymal stem cell (hMSC) conversion to osteoblasts has not been studied. There is importance to test if the DMP1 coated Ti surface would promote cell migration and attachment to the metal surface and promote the differentiation of the attached stem cells to an osteogenic lineage. This study aimed to study the human mesenchymal stem cells (hMSCs) attachment and proliferation on DMP1 coated titanium (Ti) disks compared to non-coated disks, and to assess possible osteoblastic differentiation of attached hMSCs. Sixty-eight Ti disks were divided into two groups. Group 1 disks were coated with dentin matrix protein 1 and group 2 disks served as control. Assessment with light microscopy was used to verify hMSC attachment and proliferation. Cell viability was confirmed through fluorescence microscopy and mitochondrial dehydrogenase activity. Real-time polymerase chain reaction analysis was done to study the gene expression. The proliferation assay showed significantly greater cell proliferation with DMP1 coated disks compared to the control group (p-value < 0.001). Cell vitality analysis showed a greater density of live cells on DMP1 coated disks compared to the control group. Alkaline phosphatase staining revealed higher enzyme activity on DMP1 coated disks and showed itself to be significantly higher than the control group (p-value < 0.001). von Kossa staining revealed higher positive areas for mineralized deposits on DMP1 coated disks than the control group (p-value < 0.05). Gene expression analysis confirmed upregulation of runt-related transcription factor 2, osteoprotegerin, osteocalcin, osteopontin, and alkaline phosphatase on DMP1 coated disks (p-value < 0.001). The dentin matrix protein promoted the adhesion, proliferation, facilitation differentiation of hMSC, and mineralized matrix formation.

Three-Dimensional Accuracy of Conventional Versus Digital Complete Arch Implant Impressions.

PURPOSE: The accuracy of digital impressions is still controversial for complete arch implant cases. The aim of this study is to compare the accuracy of different intraoral scanners with the conventional technique in terms of trueness and precision in a complete arch implant model. MATERIAL AND METHODS: Eight implants were inserted asymmetrically in a polyurethane edentulous mandibular model with different angulations. A 3-dimensional (3D) reference model was obtained by scanning this polyurethane model with an optical scanner. First, digital impressions were made by using 3 different intraoral scanners: Carestream 3500 (DC), Cerec Omnicam (DO) and 3Shape Trios 3 (DT). Subsequently, a nonsplinted open tray impression technique was used for conventional impression group (C) and then the master casts were digitalized with a lab scanner. Each 10 STL files belonging to 4 different impression groups were imported to a reverse engineering program, to measure distance and angle deviations from the reference model. All statistical analyses were performed after taking absolute values of the data. After comparing the impression groups with one-way ANOVA, the trueness and precision values were analyzed by Tukey post hoc test and 0.05 was used as the level of significance. RESULTS: The mean trueness of distance was 123.06 ± 89.83 µm for DC, 229.72 ± 121.34 µm for DO, 209.75 ± 47.07 µm for DT, and 345.32 ± 75.12 µm for C group (p < 0.0001). While DC showed significantly lower deviation compared to DO and C, no significant difference was found between DC and DT. C showed the highest distance deviation significantly in all groups; and no significant difference was found between DO and DT groups. In angle measurements; the trueness was 0.26° ± 0.07° for DC, 0.53° ± 0.42° for DO, 0.33° ± 0.30° for DT, and 0.74° ± 0.65° for C group. There was no significant difference between the groups in terms of angular trueness (p = 0.074). In terms of the precision for distance, the results of DC 80.43 ± 29.69 µm, DO 94.06 ± 69.96 µm, DT 35.55 ± 28.46 µm and C 66.97 ± 36.69 µm were determined (p = 0.036). The significant difference was found only between DT and DO among all groups. Finally, angular precision was determined to be 0.19° ± 0.11° for DC, 0.30° ± 0.28° for DO, 0.22° ± 0.19° for DT, and 0.50° ± 0.38° for Group C. No significant difference was found between the groups, in terms of angular precision (p = 0.053). CONCLUSIONS: All digital impression groups yielded superior data compared to conventional technique in terms of trueness. DC formed the impression group with the highest trueness in both distance and angular measurements. The results of this in vitro study suggest the use of intraoral scanners compared to the conventional impression techniques in complete arch implant cases with high angulations.

Long-term stainability of interim prosthetic materials in acidic/staining solutions.

OBJECTIVE: To evaluate the long-term color stainability, translucency, and contrast ratio (CR) of different resins used to fabricate interim prostheses after immersion in acidic/staining solutions. MATERIALS AND METHODS: A total of 160 specimens were divided into 16 groups (n = 10) according to the material (heat-polymerized acrylic resin [HPAR], auto-polymerized acrylic resin [APR], nanoparticulated bis-acrylic resin [BR], and prefabricated poly(methyl methacrylate) block for CAD/CAM [CADR]) and immersion solutions (artificial saliva, cola beverage, coffee, and red wine). A spectrophotometer was used before and after each immersion period (7, 14, 28, 90, and 180 days). Color differences (CIEDE2000 and CIELab) were calculated. A three-way repeated-measures analysis of variance and Bonferroni test (α = .05) were used. RESULTS: After 180 days, the APR presented the highest value for coffee and the CADR presented the smallest value for the cola (P < .001). For the CR, the highest values were obtained at 180 days for BR in coffee (1.35) and wine (1.18) (P < .001). Higher translucency parameters were obtained in the BR and CADR in the initial, 14, 28, and 90 days (P < .001). CONCLUSIONS: From the greatest to the smallest staining potential, the solutions were classified as: wine > coffee > cola beverage > saliva, while for the materials as: APR > BR > HPAR > CADR. CLINICAL SIGNIFICANCE: The knowledge of the long-term optical behavior of interim prosthetic materials is important for clinicians to decide which material to use to match the dietary intake of their patients and their esthetic demands. Prefabricated blocks for CAD/CAM systems have been shown to maintaining their optical characteristics even after a long period of immersion in acidic/staining solutions.

Prosthodontic Resident Selection by Postdoctoral Dental Matching Program: A National Survey by Participating Program Director.

PURPOSE: The purpose of this study was to obtain information about the resident selection and Match process that occurred for the Commission on Dental Accreditation (CODA)-accredited Advanced Education in Prosthodontics program in North America from the program directors' perspective, after the first year of implementation. MATERIALS AND METHODS: The list of Advanced Education in Prosthodontics program in CODA-accredited North American institutions was obtained from the ACP central office, and the directors of each program were identified. The surveys were distributed to 48 program directors online and results were compiled. RESULTS: Out of 48 programs, 43 directors responded to and completed the survey (90.0%), where 35 programs participated in the Match process, 5 did not, and 3 were omitted due to incomplete surveys. While the majority of programs did not see any changes in their applicant pool or their quality, 10 programs (25.0%) observed a number of increases in the application and 13 programs (32.5%) observed an increase in the quality of the applications. Among the 35 programs that participated in the Match process, the main reasons for their participation were "fairness" (48.2%), "did not want to keep moving up interview dates" (23.2%), and "have applicants come to interview as planned" (21.4%). Thirty-three programs reported that 75% to 100% of the invited applicants came to the interview (76.7%). The majority of programs that participated in Match expressed satisfaction with the process (29/33, 80.6%). Sixteen programs (45.7%) reported that they matched with 100% of their first selections. CONCLUSION: Overall response of reintroduction of the Match process for advanced prosthodontic resident selection was very positive for majority of the program directors.

Status of Sleep Apnea and Snoring Disorder Curriculum in U.S. Advanced Education Prosthodontic Programs.

PURPOSE: To assess the management of sleep apnea and snoring disorders in Advanced Education Programs in Prosthodontics (AEPP) in the United States. MATERIALS AND METHODS: A 51 item, online survey was sent to program directors at 48 AEPPs in the United States in 2015. Data results were analyzed descriptively. RESULTS: Thirty-five program directors responded to the survey. Twenty-four (68.6%, N = 35) programs report not having a dedicated course for the treatment of sleep apnea and snoring disorders. The majority (94.3%) of programs chose to treat sleep disordered breathing with oral appliance therapy and 80.0% (N = 35) of programs utilize customized sleep apnea oral devices. However, only 48.6% (N = 35) and 51.4% (N = 35) of programs regularly address sleep apnea and snoring disorders at initial examination during the comprehensive exam and medical history questionnaire, respectively. CONCLUSIONS: The confidence interval for this survey is 8.71 at a confidence level of 95% due to a response rate of 72.9%. This confidence interval suggests there is responder bias in the survey results. Therefore, the results of this survey provide a suggestion of how sleep disorders are managed in AEPPs. Programs appear to be consistent among each other with regards to treatment modalities for sleep disordered breathing. The results suggest that patients are not screened enough to receive treatment addressing sleep disorders.

Color stability of maxillofacial prosthetic silicone functionalized with oxide nanocoating.

STATEMENT OF PROBLEM: Maxillofacial prostheses made of silicone elastomers undergo undesirable color degradation over time. How this color change can be prevented is unclear. PURPOSE: The purpose of this in vitro study was to evaluate the ability of an oxide nanocoating to prevent color degradation of maxillofacial silicone elastomers after artificial accelerated aging. MATERIAL AND METHODS: A silicone elastomer with functional intrinsic pigment was tested. Specimens (N=20) were fabricated, and half of them were coated with a nanolayer of titanium dioxide (TiO2) using atomic layer deposition. Both coated and noncoated specimens (control) were exposed to artificial aging at 450 kJ/m2 of total energy. Changes in the color of all the specimens with and without TiO2 nanocoating were measured before and after the atomic layer deposition coating and before and after aging. The obtained color data were analyzed by using independent t tests and the 1-sample t test (α=.05). RESULTS: Color change (ΔE1=3.4 ±1.4) was observed for the silicone elastomers after the specimens were surface coated with TiO2 nanofilm, although this change was not statistically significant (P=.369) compared with the acceptability threshold (ΔE=3.0). Upon exposure to artificial aging, the noncoated control specimens underwent color change (ΔE2=2.5 ±0.7, P=.083 compared with the acceptability threshold). The specimens with TiO2 nanocoated surface experienced the least color change (ΔE3=1.4 ±0.6) when subjected to artificial aging, and this change was significantly lower (P<.001) than the established acceptability threshold of ΔE=3.0. In addition, the chemical analyses confirmed that the TiO2 nanocoating remained on the surface after exposure to artificial aging. CONCLUSIONS: TiO2 nanocoating was shown to be effective in reducing color degradation of the silicone elastomer exposed to artificial aging for 120 hours with 450 kJ/m2 of total energy.

Wear Characteristics and Volume Loss of CAD/CAM Ceramic Materials.

PURPOSE: In the field of prosthodontics, patients often require complex and extensive restorative care. This can involve the use of dental restorations to restore teeth on both the maxillary and mandibular arch. Current literature has evaluated the wear properties of different dental ceramics against enamel, but studies regarding dental ceramics opposing one another are limited. The purpose of this study was to assess the wear potential and wear behavior of CAD/CAM zirconia (ZR) and lithium disilicate (LD) materials against a similar ceramic material, and how the surface finish of these dental ceramics might affect patterns of wear. MATERIALS AND METHODS: Using a sphere-on-plate tribometer system, different surface finishes (glazed-G and glazed then polished-GP) of ZR and LD were evaluated following wear simulation. Artificial saliva of physiologic pH was used as a lubricant during wear simulation at 37°C. The coefficient of friction (COF) was calculated during the wear simulation. After wear simulation was complete, volume loss, surface roughness, and surface characterization of the specimens were analyzed using white-light interferometry and scanning electron microscopy (SEM). Statistical significance between materials and surface finish was established with two-way ANOVA and Bonferroni post hoc test (α = 0.05). RESULTS: Based on the 2-way ANOVA, material (p = 0.002) significantly affected the COF. LD showed a higher COF (p = 0.002) than ZR. Material (p < 0.001) and surface finish (p = 0.004) significantly affected the surface roughness inside the scar. ZR had significantly lower surface roughness compared to LD (p < 0.001). For outside scar, surface finish (p < 0.001) significantly affected the surface roughness. Polished specimens showed significantly higher roughness compared to glazed specimens for both inside (p = 0.004) and outside scar (p < 0.001). For volume loss, material (p < 0.001) and the interaction between material and surface finish (p < 0.001) were statistically significant. LD had higher volume loss than ZR (p < 0.001). For both glazed and polished finished, LD-G and LD-GP had significantly higher volume loss than ZR-G (p = 0.028), and ZR-GP (p < 0.001), respectively. SEM analysis indicated particle build-up and a grooving mechanism of wear for the LD-GP specimens. This suggested a three-body wear phenomenon occurring for LD-GP specimens, which was not visible in SEM imaging for other specimen types. CONCLUSIONS: This study demonstrated the resistance to wear and low abrasiveness of ZR when compared to LD in a simulated masticatory environment. This can be best explained by the increased strength of ZR, and the introduction of three-body wear to LD specimens from the accumulation of embedded wear debris onto its surface. Wear data and comparison of SEM images following wear simulation confirmed this interpretation.

Improving Polymethyl Methacrylate Resin Using a Novel Titanium Dioxide Coating.

PURPOSE: The objective of this study was to improve the surface characteristics of poly (methyl methacrylate) (PMMA) by developing a novel, thin film coating process and to characterize the resulting coated surface. MATERIALS AND METHODS: An atomic layer deposition (ALD) technique was developed to deposit a titanium dioxide (TiO2 ) nano-thin film on PMMA. The surface wettability for both coated and uncoated PMMA was determined by measuring water contact angle. Wear resistance was assessed using a mechanical tooth-brushing device with a 50 g load for 6000 strokes after 5 months of water storage. A denture cleanser challenge test was performed by using sonication in 3.8% sodium perborate for 1 hour with aged specimens. X-ray photoelectron spectroscopy (XPS) was used before and after the brushing test and challenge test to analyze the PMMA surface chemical composition. The mechanical strength of coated and uncoated PMMA was measured using a three-point bending test. Surface microbial interactions were also evaluated by assessing Candida albicans biofilm attachment. RESULTS: Nano-TiO2 coating (30 nm thick) was successfully deposited on PMMA at 65°C. After coating, water contact angle decreased from 70° to less than 5°. After brushing test, the coating remained intact. XPS analysis revealed no loss of TiO2 from coated specimens following brushing and denture cleanser sonication for 1 hour. There was no statistically significant difference in mechanical strength (MPa) (mean ± SD) between PMMA (139.4 ± 11.3) and TiO2 -PMMA (160.7 ± 37.1) (p = 0.0995). C. albicans attachment decreased by 63% to 77% on the coated PMMA surface. CONCLUSIONS: ALD is a promising technique to modify surface properties of PMMA and resulted in a stable adherent thin film. By depositing a TiO2 coating, PMMA surface properties may lead to significantly reduced microorganism adhesion and easier pathogen removal from PMMA. For patients who wear dentures, reducing the oral microbial biofilm burden using a TiO2 -coated PMMA surface could positively impact their oral and systemic health.

Dose-response effect of chlorhexidine on a multispecies oral biofilm formed on pure titanium and on a titanium-zirconium alloy.

This study aimed to test the dose-response effect of chlorhexidine on multispecies biofilms formed on commercially pure titanium (cpTi) and titanium-zirconium (TiZr) alloy. Biofilms were formed on cpTi and TiZr discs and treated two times per day with five different chlorhexidine concentrations (0.12, 0.20, 0.50, 1, 2%). The biofilms were collected for microbiological, biochemical and microscopic analyses. The significance of differences among groups was evaluated by linear regression, ANOVA, Bonferroni and Tukey tests. The mean number of colony-forming units decreased as the chlorhexidine concentration increased for both cpTi and TiZr (p < 0.05). The maximum effect was observed with the 0.5% concentration. Confocal microscopy images suggested an increase in the number of dead bacterial cells with increased chlorhexidine concentration. The biofilm pH increased after chlorhexidine exposure (p < 0.05). Chlorhexidine showed an antimicrobial dose-response effect in controlling biofilm on cpTi and TiZr. 0.5% chlorhexidine can be used to achieve the maximum antimicrobial effect on both materials.