ChatGPT-A double-edged sword for healthcare education? Implications for assessments of dental students.

INTRODUCTION: Open-source generative artificial intelligence (AI) applications are fast-transforming access to information and allow students to prepare assignments and offer quite accurate responses to a wide range of exam questions which are routinely used in assessments of students across the board including undergraduate dental students. This study aims to evaluate the performance of Chat Generative Pre-trained Transformer (ChatGPT), a generative AI-based application, on a wide range of assessments used in contemporary healthcare education and discusses the implications for undergraduate dental education. MATERIALS AND METHODS: This was an exploratory study investigating the accuracy of ChatGPT to attempt a range of recognised assessments in healthcare education curricula. A total of 50 independent items encompassing 50 different learning outcomes (n = 10 per item) were developed by the research team. These included 10 separate items based on each of the five commonly used question formats including multiple-choice questions (MCQs); short-answer questions (SAQs); short essay questions (SEQs); single true/false questions; and fill in the blanks items. Chat GPT was used to attempt each of these 50 questions. In addition, ChatGPT was used to generate reflective reports based on multisource feedback; research methodology; and critical appraisal of the literature. RESULTS: ChatGPT application provided accurate responses to majority of knowledge-based assessments based on MCQs, SAQs, SEQs, true/false and fill in the blanks items. However, it was only able to answer text-based questions and did not allow processing of questions based on images. Responses generated to written assignments were also satisfactory apart from those for critical appraisal of literature. Word count was the key limitation observed in outputs generated by the free version of ChatGPT. CONCLUSION: Notwithstanding their current limitations, generative AI-based applications have the potential to revolutionise virtual learning. Instead of treating it as a threat, healthcare educators need to adapt teaching and assessments in medical and dental education to the benefits of the learners while mitigating against dishonest use of AI-based technology.

Artificial intelligence and smile design: An e-Delphi consensus statement of ethical challenges.

PURPOSE: Smile design software increasingly relies on artificial intelligence (AI). However, using AI for smile design raises numerous technical and ethical concerns. This study aimed to evaluate these ethical issues. METHODS: An international consortium of experts specialized in AI, dentistry, and smile design was engaged to emulate and assess the ethical challenges raised by the use of AI for smile design. An e-Delphi protocol was used to seek the agreement of the ITU-WHO group on well-established ethical principles regarding the use of AI (wellness, respect for autonomy, privacy protection, solidarity, governance, equity, diversity, expertise/prudence, accountability/responsibility, sustainability, and transparency). Each principle included examples of ethical challenges that users might encounter when using AI for smile design. RESULTS: On the first round of the e-Delphi exercise, participants agreed that seven items should be considered in smile design (diversity, transparency, wellness, privacy protection, prudence, law and governance, and sustainable development), but the remaining four items (equity, accountability and responsibility, solidarity, and respect of autonomy) were rejected and had to be reformulated. After a second round, participants agreed to all items that should be considered while using AI for smile design. CONCLUSIONS: AI development and deployment for smile design should abide by the ethical principles of wellness, respect for autonomy, privacy protection, solidarity, governance, equity, diversity, expertise/prudence, accountability/responsibility, sustainability, and transparency.

Electrochemical decontamination of titanium dental implants. An in vitro biofilm model study.

OBJECTIVES: The objective of this study is to study the effect of electrochemical treatment on biofilms developed on titanium dental implants, using a six-species in vitro model simulating subgingival oral biofilms. MATERIALS AND METHODS: Direct electrical current (DC) of 0.75 V, 1.5 V, and 3 V (anodic polarization, oxidation processes) and of -0.75 V, -1.5 V, and -3 V (cathodic polarization, reduction processes) was applied between the working and the reference electrodes for 5 min on titanium dental implants, which have been previously inoculated with a multispecies biofilm. This electrical application consisted of a three-electrode system where the implant was the working electrode, a platinum mesh was the counter electrode, and an Ag/AgCl electrode was the reference. The effect of the electrical application on the biofilm structure and bacterial composition was evaluated by scanning electron microscopy and quantitative polymerase chain reaction. A generalized linear model was applied to study the bactericidal effect of the proposed treatment. RESULTS: The electrochemical construct at 3 V and -3 V settings significantly reduced total bacterial counts (p < .05) from 3.15 × 106 to 1.85 × 105 and 2.92 × 104 live bacteria/mL, respectively. Fusobacterium nucleatum was the most affected species in terms of reduction in concentration. The 0.75 V and -0.75 V treatments had no effect on the biofilm. CONCLUSION: Electrochemical treatments had a bactericidal effect on this multispecies subgingival in vitro biofilm model, being the reduction more effective than the oxidative treatment.

Admission criteria and academic performance in medical school.

BACKGROUND: Different variables have been used to predict the academic performance of students in medical schools. The aim of this study was to assess the effect of demographics, admission system, and high-school background on the academic performance of medical students. METHODS: We conducted this longitudinal cohort study on 808 students admitted to the Faculty of. Medicine at the University of Jordan (Amman, Jordan), in the years 2012 and 2013. Admission pathway, and academic performance data were collected and analyzed. RESULTS: A total of 808 students [i.e., 426 (52.7%) females, and 382(47.3%) males] were identified. Admitted students were holding 17 different types of high school degrees, and were accepted through 6 different quota pathways (open competition [National unified admission], underprivileged ["Makrumah"], parallel, children of university staff, international students, and others). Students admitted through the open competition and the underprivileged quota(Makrumah) were more likely to graduate on time and had higher graduation grades while students admitted through the parallel, international and others quota were more likely to fail and had lower graduation grades. Regarding highs school degrees, the students that were more likely to graduate were those with IB and the Jordanian high school degrees. The highest graduation GPA was for IB students followed by SAT, IGCSE as well as Jordanian and Syrian high school degrees respectively. IB, Jordanian, Kuwaiti and IGSC high school grades were significantly correlated with the graduation GPA. CONCLUSIONS: Admission criteria such as type of high school degree and grades as well as admission pathways can predict the likelihood to graduate and the graduation GPA of medical students. Open competition and underprivileged admission pathways as well as IB, IGCSE and Jordanian high school degrees seem to be better predictors of student performance in the medical school.

The impact of periodontal disease on the clinical outcomes of COVID-19: A systematic review and meta-analysis.

BACKGROUND: A possible relationship between periodontitis (PD) and COVID-19 and its adverse outcomes has been suggested. Hence, the present systematic review and meta-analysis aimed to investigate the available evidence regarding the potential association between periodontitis (PD) and COVID-19 and its adverse outcomes. MATERIALS AND METHODS: PubMed, Scopus, Web of Science, and Google Scholar were searched for relevant studies published up to April 15th, 2023. Studies that evaluated the association between PD and COVID-19 were included. Risk of bias was evaluated by two reviewers, and meta-analyses were performed using RevMan 5.3 software. RESULTS: A total of 22 studies involving 92,535 patients from USA, Europe, Asia, the Middle East and South America were included; of these, 12 were pooled into the meta-analysis. Most of the studies (19 studies) reported a significant association between PD and COVID-19. The pooled data found a significant association between PD and COVID-19 outcomes: more severe symptoms (OR = 6.95, P = 0.0008), ICU admissions (OR = 3.15, P = 0.0001), and mortality (OR = 1.92, P = 0.21). Additionally, compared to mild PD, severe PD was significantly associated with higher risks of severe COVID-19 outcomes: severe symptoms (P = 0.02); ICU admission (P = 0.0001); and higher mortality rates (P = 0.0001). The results also revealed 58% higher risk for COVID-19 infection in patients with PD (P = 0.00001). CONCLUSIONS: The present findings suggest a possible association between poor periodontal health and the risk of poor COVID-19 outcomes. However, owing to the observed methodological heterogeneity across the included studies, further prospective cohort studies with standardized methodologies are warranted to further unravel the potential association between periodontal disease and COVID-19 and its adverse outcomes.

Patient-reported outcomes and framework fit accuracy of removable partial dentures fabricated using digital techniques: A systematic review and meta-analysis.

PURPOSE: This review aimed to summarize the evidence on patient-reported outcomes and clinical performance of digitally fabricated removable partial dentures (RPDs) compared to traditionally fabricated dentures. METHODS: Three databases were systematically searched (PubMed, CENTRAL, and Wiley online library) for clinical studies comparing digitally and conventionally fabricated RPDs regardless of data acquisition methods used for fabrication. The Cochrane Collaboration risk of bias assessment tool 2 and the Oxford Center for Evidence-based Medicine tool were used to assess risk of bias, and level of evidence, respectively. Descriptive narrative analysis was used to summarize data on patient-reported outcomes, as there were inadequate studies to pool data in a meta-analysis. A random-effects model was used to analyze the data of framework fit accuracy. RESULTS: Ten randomized controlled trials were included in the systematic review, and 4 were included in the meta-analysis. Two studies showed that digitally fabricated RPDs are associated with higher patient satisfaction than conventionally fabricated RPDs (with a mean difference of 12.5 mm on a 100-satisfaction scale, p = .008). The pooled standardized mean difference for framework fit accuracy was 0.49 (p = 0.02) in favor of conventionally fabricated RPDs, which showed that conventionally fabricated RPDs have a quantitatively better fit compared to digitally fabricated RPDs. However, clinical evaluation studies showed that both frameworks have clinically acceptable fit. CONCLUSIONS: Current evidence shows that digitally fabricated RPDs are associated with higher patient satisfaction compared to conventionally fabricated RPDs. However, the scarcity of literature here warrants the generalization of this conclusion. Both digitally and conventionally fabricated metal RPD frameworks showed acceptable fit clinically.

Artificial intelligence: is it more accurate than endodontists in root canal therapy?

DATA SOURCES: The following databases were electronically searched (up to 20 March 2022): PubMed, Scopus, Google Scholar, and Cochrane Library. This was followed by hand-searching the reference lists of the included articles. The search was restricted to articles published in English. The aim of this study was to evaluate the effectiveness of artificial intelligence in identifying, analyzing, and interpreting radiographic features related to endodontic therapy. STUDY SELECTION: The selection criteria were limited to trials evaluating the effectiveness of artificial intelligence in identifying, analyzing, and interpreting radiographic features related to endodontic therapy. TYPES OF STUDIES: Clinical, ex-vivo, and in-vitro trials. TYPES OF RADIOGRAPHIC IMAGES: Two-dimensional intra-oral imaging (bitewings and/or periapicals), panoramic radiographs (PRs), and cone beam computed tomography (CBCT). EXCLUSION CRITERIA: 1) Case reports, letters, and commentaries; 2) Reviews, conferences, and books; 3) Inaccessible reports. DATA EXTRACTION AND SYNTHESIS: The titles and abstracts of the results of the searches were screened by two authors against the inclusion criteria. The full text of any potentially relevant abstract and title were retrieved for more comprehensive assessment. The risk of bias was assessed initially by two examiners and then by two authors. Any discrepancies were resolved through discussion and consensus. RESULTS: Out of the 1131 articles which were identified in the initial search, 30 were considered relevant, and only 24 articles were eventually included. The exclusion of the six articles was related to the absence of appropriate clinical or radiological data. Meta-analysis was not performed due to high heterogeneity. Various degrees of bias were detected in more than 58% of the included studies. CONCLUSIONS: Although most of the included studies were biased, the authors concluded that the use of artificial intelligence can be an effective alternative in identifying, analyzing and interpreting radiographic features related to root canal therapy.

Periodontitis and coronavirus disease 2019.

The coronavirus disease 2019 caused by severe acute respiratory syndrome coronavirus 2 is usually a mild condition; however, in some cases it can result in severe sickness and even death. Thus, understanding the reasons behind these grave outcomes is of great importance. Coronavirus disease 2019 and periodontitis share some intriguing characteristics. They can both lead to systemic inflammation and alterations of coagulation pathways, and both share confounding factors, such as diabetes, hypertension, and obesity. Accordingly, a possible association between these conditions has been hypothesized in the literature. The objective of this review was to evaluate the scientific evidence linking these diseases and the possible underlying mechanisms. Evidence has shown that coronavirus disease 2019 presents oral manifestations and can even affect periodontal tissues. Moreover, some studies have shown a possible association between coronavirus disease 2019 severity and the presence of periodontitis. Current evidence suggests that this association could be explained through the direct role of periodontal bacteria in aggravating lung infections, as well as through the indirect effect of periodontitis in inducing systemic inflammation and priming of the immune system to an exacerbated reaction to severe acute respiratory syndrome coronavirus 2 infection. Future research is needed to confirm these observations and explore the possible role that periodontal care might play in the coronavirus disease 2019 pandemic.

Association of periodontal therapy, with inflammatory biomarkers and complications in COVID-19 patients: a case control study.

BACKGROUND: In previous studies, COVID-19 complications were reported to be associated with periodontitis. Accordingly, this study was designed to test the hypothesis that a history of periodontal therapy could be associated with lower risk of COVID-19 complications. METHODS: A case-control study was performed using the medical health records of COVID-19 patients in the State of Qatar between March 2020 and February 2021 and dental records between January 2017 and December 2021. Cases were defined as COVID-19 patients who suffered complications (death, ICU admissions and/or mechanical ventilation); controls were COVID-19 patients who recovered without major complications. Associations between a history of periodontal therapy and COVID-19 complications were analysed using logistic regression models adjusted for demographic and medical factors. Blood parameters were compared using Kruskal-Wallis test. RESULTS: In total, 1,325 patients were included. Adjusted odds ratio (AOR) analysis revealed that non-treated periodontitis was associated with significant risk of need for mechanical ventilation (AOR = 3.91, 95% CI 1.21-12.57, p = 0.022) compared to periodontally healthy patients, while treated periodontitis was not (AOR = 1.28, 95% CI 0.25-6.58, p = 0.768). Blood analyses revealed that periodontitis patients with a history of periodontal therapy had significantly lower levels of D-dimer and Ferritin than non-treated periodontitis patients. CONCLUSION: Among COVID-19 patients with periodontal bone loss, only those that have not received periodontal therapy had higher risk of need for assisted ventilation. COVID-19 patients with a history of periodontal therapy were associated with significantly lower D-dimer levels than those without recent records of periodontal therapy. CLINICAL RELEVANCE: The fact that patients with treated periodontitis were less likely to suffer COVID-19 complications than non-treated ones further strengthen the hypothesis linking periodontitis to COVID-19 complications and suggests that managing periodontitis could help reduce the risk for COVID-19 complications, although future research is needed to verify this.

Titanium-Containing Silicate-Based Sol-Gel Bioactive Glass: Development, Characterization, and Applications.

Bioactive glasses are surface-reactive glasses that, when placed in physiological fluid, undergo a transformation from glass to hydroxyapatite. Doping the bioactive glass with metallic ions can impart desirable and unique properties that are not inherent to natural hydroxyapatite. Once such ion is titanium. Titanium exists in trace amounts in native dental enamel, and its presence has been correlated with increased tooth hardness and brightness, both desirable clinical properties. Synthetic titanium-substituted hydroxyapatite exhibits better mechanical and antibacterial properties and demonstrates potential for an improved cellular response when compared to unmodified hydroxyapatite with applications in the broader field of bone tissue engineering. In this work, we use the sol-gel method to synthesize a titanium-containing silicate-based bioactive glass aimed at generating titanium-substituted hydroxyapatite on the glass surface upon immersion in body fluid. Titanium is homogeneously distributed throughout our glass, which keeps its amorphous nature. After 14 days of immersion in simulated body fluid, the glass forms a titanium-substituted hydroxyapatite on its surface. Enamel surfaces treated with the titanium-containing glass show significantly increased microhardness compared to enamel surfaces treated with a control glass, confirming the potential for the proposed glass in enamel remineralization. We also show that the presence of titanium in the glass promotes cell differentiation toward bone formation, suggesting further applications for this material in the broader field of bone tissue engineering.

Association between periodontitis and severity of COVID-19 infection: A case-control study.

AIM: COVID-19 is associated with an exacerbated inflammatory response that can result in fatal outcomes. Systemic inflammation is also a main characteristic of periodontitis. Therefore, we investigated the association of periodontitis with COVID-19 complications. MATERIALS AND METHODS: A case-control study was performed using the national electronic health records of the State of Qatar between February and July 2020. Cases were defined as patients who suffered COVID-19 complications (death, ICU admissions or assisted ventilation), and controls were COVID-19 patients discharged without major complications. Periodontal conditions were assessed using dental radiographs from the same database. Associations between periodontitis and COVID 19 complications were analysed using logistic regression models adjusted for demographic, medical and behaviour factors. RESULTS: In total, 568 patients were included. After adjusting for potential confounders, periodontitis was associated with COVID-19 complication including death (OR = 8.81, 95% CI 1.00-77.7), ICU admission (OR = 3.54, 95% CI 1.39-9.05) and need for assisted ventilation (OR = 4.57, 95% CI 1.19-17.4). Similarly, blood levels of white blood cells, D-dimer and C Reactive Protein were significantly higher in COVID-19 patients with periodontitis. CONCLUSION: Periodontitis was associated with higher risk of ICU admission, need for assisted ventilation and death of COVID-19 patients, and with increased blood levels of biomarkers linked to worse disease outcomes.

Differences in platelet-rich plasma composition influence bone healing.

AIM: Platelet-rich plasma (PRP) is an autologous blood-derived material that has been used to enhance bone regeneration. Clinical studies, however, reported inconsistent outcomes. This study aimed to assess the effect of changes in leucocyte and PRP (L-PRP) composition on bone defect healing. MATERIALS AND METHODS: L-PRPs were prepared using different centrifugation methods and their regenerative potential was assessed in an in-vivo rat model. Bilateral critical-size tibial bone defects were created and filled with single-spin L-PRP, double-spin L-PRP, or filtered L-PRP. Empty defects and defects treated with collagen scaffolds served as controls. Rats were euthanized after 2 weeks, and their tibias were collected and analysed using micro-CT and histology. RESULTS: Double-spin L-PRP contained higher concentrations of platelets than single-spin L-PRP and filtered L-PRP. Filtration of single-spin L-PRP resulted in lower concentrations of minerals and metabolites. In vivo, double-spin L-PRP improved bone healing by significantly reducing the size of bone defects (1.08 ± 0.2 mm3 ) compared to single-spin L-PRP (1.42 ± 0.27 mm3 ) or filtered L-PRP (1.38 ± 0.28 mm3 ). There were fewer mast cells, lymphocytes, and macrophages in defects treated with double-spin L-PRP than in those treated with single-spin or filtered L-PRP. CONCLUSION: The preparation method of L-PRP affects their composition and potential to regenerate bone.

Could vagus nerve stimulation influence bone remodeling?

OBJECTIVES: To investigate the effect of vagus nerve stimulation (VNS) on the bone mineral density (BMD) in epileptic patients. METHODS: A prospective cohort study was conducted on individuals with refractory seizures who underwent VNS surgery between January 2012 and December 2018. BMD was measured preoperatively and between 6 months and one year after surgery. RESULTS: Twenty-one patients (mean age (±SD)=23.6±12.3 years) were recruited for the implantation of a VNS device. The mean absolute increase in lumbar BMD in the 21 patients was 0.04±0.04 g/cm2 resulting in an overall percent increase from baseline of 4.7±6.1%. BMD increased by an amount ≥ the least significant change (LSC) for the lumbar spine in 13 patients (61.9%). The lumbar Z score also increased in these patients from -1.22±1.15 to -0.88±1.22, P=0.006). Pre and Post VNA femoral BMD was measured in only 11 patients and, of those 3 showed a significant increase in BMD, 1 a significant decrease and 7 no change. CONCLUSION: The implantation of a VNS was associated with an increase in lumbar BMD. This study could lead to a new application for VNS in the treatment of osteoporosis.

The effect of nanocoatings of SiO2, TiO2, and ZrO2 on titanium-porcelain bonding.

STATEMENT OF PROBLEM: Durable titanium-porcelain bonding is challenging because of the formation of a thick oxide layer on the surface during porcelain firing. PURPOSE: The purpose of this in vitro study was to evaluate how atomic layer deposition (ALD) of different oxide coatings affected titanium-porcelain bonding and failure types. MATERIAL AND METHODS: Forty-four airborne-particle abraded Type-2 titanium specimens were coated by ALD with either SiO2, TiO2, or ZrO2 (n=11) at a thickness of 30 nm, whereas control specimens were left uncoated (n=11) (airborne-particle abraded only). The surface roughness of the specimens was analyzed with a profilometer before applying porcelain (Vita Titankeramic). Titanium-porcelain bonding was analyzed by using a 3-point bend test. Surface properties and titanium-porcelain interfaces were examined under scanning electron microscopy combined with energy-dispersive spectroscopy, and failure types were evaluated by using a stereomicroscope. Surface roughness and bond strength data were analyzed by 1-way ANOVA and Tukey HSD tests. Failure type data were analyzed by the Fisher-Freeman-Halton exact test (α=.05). RESULTS: All nanocoatings increased surface roughness values, but only TiO2 and ZrO2 coatings showed statistically significant higher roughness than the control surfaces (P<.001). Specimens coated with SiO2 (28.59 ±4.37 MPa) and TiO2 (26.86 ±3.66 MPa) presented significantly higher bonding strength than control (22.04 ±4.59 MPa) specimens (P<.01). Fracture types of different groups were not statistically different (P>.05). CONCLUSIONS: Nanocoating titanium surfaces with SiO2 and TiO2 by using the ALD technique significantly improved titanium-porcelain bonding.

Script concordance tests: A call for action in dental education.

The Script Concordance Test (SCT) is an educational tool that aims to assess the ability to interpret medical information under conditions of uncertainty. It is widely used and validated in health education, but almost unknown in dentistry. Based on authentic clinical problem-solving situations, it allows to assess clinical reasoning that experienced health workers develop over the years. A specific scoring system, dedicated to SCT, considers the variability of responses of practitioners in the same clinical situations. Finally, the scores generated by SCT reflect the respondents' ability to interpret clinical data compared to experienced clinicians. This article aims to familiarise the dental educators' community with SCT construction, optimisation and its possible applications.

Multiscale structural evolution of citrate-triggered intrafibrillar and interfibrillar mineralization in dense collagen gels.

The mineralized extracellular matrix of bone is an organic-inorganic nanocomposite consisting primarily of carbonated hydroxyapatite, fibrous type I collagen, noncollagenous proteins, proteoglycans, and diverse biomolecules such as pyrophosphate and citrate. While much is now known about the mineralization-regulating role of pyrophosphate, less is known about the function of citrate. In order to assess the effect of negatively charged citrate on collagen mineralization, citrate-functionalized, bone osteoid-mimicking dense collagen gels were exposed to simulated body fluid for up to 7 days to examine the multiscale evolution of intra- and interfibrillar collagen mineralization. Here, we show by increases in methylene blue staining that the net negative charge of collagen can be substantially augmented through citrate functionalization. Structural and compositional analyses by transmission and scanning electron microscopy (including X-ray microanalysis and electron diffraction), and atomic force microscopy, all demonstrated that citrate-functionalized collagen fibrils underwent extensive intrafibrillar mineralization within 12 h in simulated body fluid. Time-resolved, high-resolution transmission electron microscopy confirmed the temporal evolution of intrafibrillar mineralization of single collagen fibrils. Longer exposure to simulated body fluid resulted in additional interfibrillar mineralization, all through an amorphous-to-crystalline transformation towards apatite (assessed by X-ray diffraction and attenuated total reflection-Fourier-transform infrared spectroscopy). Calcium deposition assays indicated a citrate concentration-dependent temporal increase in mineralization, and micro-computed tomography confirmed that >80 vol% of the collagen in the gels was mineralized by day 7. In conclusion, citrate effectively induces mesoscale intra- and interfibrillar collagen mineralization, a finding that advances our understanding of the role of citrate in mineralized tissues.

Ranitidine Impairs Bone Healing and Implant Osseointegration in Rats' Tibiae.

PURPOSE: Ranitidine has been found to have an impact on bone metabolism by suppressing osteoclastogenesis. We hypothesized that the use of ranitidine would impair bone healing and implant osseointegration. This study investigated the effect of postoperative administration of ranitidine on bone healing and osseointegration in rats. MATERIALS AND METHODS: Twenty-two Sprague-Dawley rats underwent surgery to create a unicortical bone defect in each tibia. A titanium implant was placed on the right tibial defect, whereas the contralateral defect was left unfilled. After surgery, the rats were randomly divided into 2 groups receiving a daily dose of ranitidine or saline solution for 14 days and then euthanized for assessment of bone healing and osseointegration using micro-computed tomography (CT) and histomorphometry. RESULTS: Micro-CT analysis of the bone defect showed a larger bone defect volume in the ranitidine group (0.82 ± 0.13 µL vs 0.66 ± 0.16 µL, P = .034), thinner cortical thickness (0.54 ± 0.07 mm vs 0.63 ± 0.11 mm, P = .026), and less bone regeneration at the defect site (40% ± 12% vs 57% ± 11%, P = .003). Implant-site micro-CT analysis showed less osseointegration in the ranitidine group (34.1% ± 2.7% vs 43.5% ± 2.1%, P = .014), and implant-site histologic analysis showed less medullary (P = .021), cortical (P = .001), and total (P = .003) bone-implant contact and less peri-implant bone volume-tissue volume (P = .002) in the ranitidine group. Histologic analysis for osteoclastic activity showed a lower number of osteoclasts in the ranitidine group (4.8 ± 2.4 mm-2 vs 9.1 ± 2.1 mm-2, P = .026). CONCLUSIONS: The postoperative use of ranitidine impaired bone healing and osseointegration.

Microcomputed tomography assessment of microcracks following temporary filling placement.

OBJECTIVES: The aim of this study was to detect microcracks and cuspal deflection in tooth crown following the application of temporary filling using microcomputed tomography (micro-CT). MATERIALS AND METHODS: A mesio-occluso-distal cavity preparation was performed, followed by endodontic access cavity preparation and root canal shaping. Cavities were classified into two groups according to the type of temporary filling material used; Coltosol F (Coltene Whaledent) (Group I) and intermediate restorative material (IRM; Dentsply Sirona) (Group II). Micro-CT images before and after temporary filling material placement were obtained and then compared for the presence of microcracks. Microcracks considered in our data analysis were the new ones that were detected after temporary filling material placement. The mean number of new microcracks per tooth recorded for both groups were compared using Mann-Whitney U test. The number of teeth with new microcracks in both groups was compared by chi-square test. Repeated measures t test was conducted to observe the effect of temporary filling on the intercuspal distance (ICD). Also, the mean difference in the ICDs detected after temporary filling placement in both groups were compared by independent t test. The significance level was set at 5%. RESULTS: Eleven microcracks were detected in group I, whereas only three microcracks were observed in group II (p < 0.01). The mean numbers of new microcracks were 0.84 and 0.21 in group I and II, respectively (p < 0.01). There was no significant difference in the ICDs in group I (0.006±0.02 mm) and group II (0.018 ± 0.03 mm) (p > 0.26). Most of the microcracks were found in the dentin structure. The cavity's box area was more affected by new microcracks, compared with the cavity's coronal area. The new microcracks were mainly observed in the mesiodistal direction. No complete fractures were reported in our study. CONCLUSIONS: Both temporary fillings induced microcracks; Coltosol F can induce more microcracks than IRM in premolar teeth after 1-week storage. Most of the microcracks were observed in the dentin structure of the cavity's box area running mesiodistally. CLINICAL RELEVANCE: The results indicated that the tested temporary fillings developed microcracks on the tooth crown with slight deflection of the cusps.

Evaluation of the design-driven prediction of removable partial denture retention.

STATEMENT OF PROBLEM: Removable partial dentures (RPDs) are a cost-effective treatment designed to replace missing teeth for partially edentulous patients. However, RPDs often have insufficient retention, which results in treatment failure and patient dissatisfaction. PURPOSE: The purpose of this clinical study was to investigate the factors related to RPD retention that affect patient satisfaction, to clinically validate a newly published model for predicting RPD retention based on the number and position of missing teeth and clasps, and to identify the predictions of patient satisfaction to improve the guidelines for RPD design. MATERIAL AND METHODS: Seventy-five patients treated with 107 RPDs delivered at the McGill University Dental Clinic (Montreal, Canada) and Estaing University Hospital (Clermont-Ferrand, France) participated in this study. Data on the RPD design were collected from the clinical records, and the retention of each RPD was tested with the mathematical model designed for predicting RPD retention. Data on patient satisfaction with their RPDs were collected by using a standardized questionnaire (McGill Denture Satisfaction Instrument). Statistical analysis of factors related to RPD retention and patient satisfaction was performed by using the chi-square test and Mann-Whitney test, while the developed model for predicting RPD retention was evaluated by using sensitivity and specificity analysis. RESULTS: The average satisfaction score for all RPDs was 8.2 ±1.7 out of 10. Patients were more satisfied with RPDs in the maxillary arch, tooth-supported, or retained by ≥3 clasps than with RPDs in the mandibular arch, with distal extension bases, or retained by <3 clasps. The materials used for RPD fabrication (metal-based or acrylic resin-based), the number of missing teeth, and the presence of indirect retention were not associated with patient satisfaction. Participants were significantly more satisfied with RPD designs predicted by the developed mathematical model to have enough retention than with RPD designs predicted to have insufficient retention. The mathematical model for predicting the RPD retention showed a clinical specificity of 83% in predicting patient satisfaction. CONCLUSIONS: RPD retention predicted from the number and position of clasps and missing teeth might help to determine patient satisfaction. In addition, patient satisfaction with RPDs was influenced by the arch type, the presence of a distal extension base, and the number of clasps.

Tooth Shade Preferences among the General Public.

PURPOSE: To identify laypersons' most preferred tooth shade as a function of observer and patient factors, namely patients' skin shade and observers' socio-demographics. MATERIALS AND METHODS: Two online surveys using computer-designed perioral images with different shades of the skin and teeth were distributed to participants in Montreal (Canada) and San Francisco (USA). The first survey (n = 120) was designed to assess public preferences of tooth shade value, hue and chroma as a function of the skin color of the perioral image (model), and the demographic characteristics of the observer. The first survey included 6 sets of 9 identical perioral images. A different skin shade (from very dark to very light) was used for each set of images, and each set of images presented teeth with different tooth shades which included three different levels of value (2M1, 3M1, 4M1), hue (3L1.5, 3M1, 3R1.5), and chroma (3M1, 3M2, 3M3) of the Vita 3D Master shade guide. Participants were asked to choose their preferred image for each category (value, hue, chroma) within each set of skin shades. A second survey was performed to pinpoint the tooth shade that is preferred the most by the general public. In this survey, images with four tooth shades (1M1, 2M1, 3M1, 4M1) and 6 skin shades were distributed (n = 70). Ordinal logistic regression was used to identify significant predictors of preferred tooth shades. RESULTS: Most of the participants preferred teeth with the highest value (54%), a neutral hue (59%) and the lowest chroma (89%). About 75% of the participants preferred 1M1 the lightest tooth shade over other shades regardless of their demographics or skin color of the model. Among the observer-related variable, age was the most significant predictor of people preferred tooth shade (p = 0.019). CONCLUSION: This study showed that there are common preferences in terms of tooth shade value, hue and chroma among participants regardless of demographic variables and facial skin shades. This data could guide dentists for tooth shade selection in the clinical practice.