Correction: What influences the clinical decision-making of dentists? A cross-sectional study.

[This corrects the article DOI: 10.1371/journal.pone.0233652.].

What influences the clinical decision-making of dentists? A cross-sectional study.

Clinical decision-making is a complex process influenced by clinical and non-clinical factors. The aim of this study was to investigate the association between provider, patient, and practice factors with clinical decision-making among dentists in Ontario, Canada's most populated province and its largest dental care market. This was a cross-sectional, self-administered survey of a random sample of general dentists in Ontario (n = 3,201). The 46-item survey collected demographic, professional, and practice information. The outcome (treatment intensity) was measured using a set of clinical scenarios, which categorized dentists as either relatively aggressive or conservative in their treatment decisions. Associations were assessed using bivariate analysis and logistic regressions. One thousand and seventy-five dentists responded (33.6% response rate). Age (p = 0.001), place of initial training (p<0.001), number of dependents (p = 0.001), number of hygienists employed (p = 0.001), and perceptions of practice loans (p = 0.020) were associated with treatment intensity. Dentists who were <40-years old (OR = 2.06, 95% CI:1.39-3.06, p<0.001), American-trained (OR = 2.48, 95% CI:1.51-4.06, p<0.001), and perceived their practice loans as large (OR = 1.57, 95% CI:1.02-2.42, p = 0.039), were relatively more aggressive in their treatment decisions. Various non-clinical factors appear to influence the clinical decision-making of dentists in Ontario.

Does competition affect the clinical decision-making of dentists? A geospatial analysis.

OBJECTIVES: To investigate the association between dentists' geographic density and perceptions of market competition with clinical decision-making among a representative sample of dentists in Ontario, Canada's most populated province. METHODS: Competition was quantified using dentist density, defined as the number of dental clinics lying within a one kilometre radius around the respondents' clinic address and by self-reported perceived pressure from other dental clinics. The outcome (clinical decision-making or treatment intensity) was measured using a set of clinical scenarios, which categorized dentists as either relatively aggressive or conservative. Associations were assessed using bivariate analysis and logistic and linear regression. RESULTS: Dentists who perceived large competitive pressure from other dentists (OR = 1.63, 95% CI: 1.07-2.49) were relatively more aggressive in their treatment choices. Interestingly, dentists located in very low dentist density areas (OR = 1.31, 95% CI: 1.03-1.68) were also relatively more aggressive in their treatment choices. CONCLUSION: This study is the first to explore the impact of competition on the clinical decision-making of dentists in a Canadian context. It presents a valuable addition to the competition literature and helps to understand current dynamics in the Canadian dental care market.

Perceived professional roles and implications for clinical decision-making.

OBJECTIVES: This study aims to (a) investigate the relationship between dentists' perceived professional role (PPR), defined as the belief that they are health care professionals versus business people, and treatment intensity, determined by the aggressiveness of clinical approaches, such as in number or scope, and (b) identify the demographic and practice characteristics that have a relationship to PPR. METHODS: A 46-item survey with questions on dentists' demographic and professional characteristics was mailed to a random sample of 3,201 general dentists in Ontario, Canada. PPR was measured by visual analog scale and by Likert-type scale questions, which have been validated in the literature in terms of their ability to measure PPR. Treatment intensity was measured by a set of case scenarios. Univariate, bivariate, and multivariable analyses were performed. RESULTS: One-thousand and seventy-five dentists returned usable surveys (33.6% response rate). When using the two methods to measure PPR, visual analog scale and Likert-type scale questions, dentists who identified as business people tended to have a higher treatment intensity compared to those who identified as health care professionals (p < 0.1 and p < 0.05, respectively). In multivariable logistic regression, years of practice, number of technologies used in a practice, and perceiving other dentists as competitors rather than colleagues were significant predictors of identifying as a business person. CONCLUSIONS: Dentists' PPRs had a significant relationship to the aggressiveness of treatment decisions. Demographic and practice characteristics also had significant relationships to PPR. These findings may have implications for public trust and dentistry's status as a health care profession.

Tumor size is a major determinant of prognosis of resected stage I hepatocellular carcinoma.

PURPOSE: The current American Joint Committee on Cancer (AJCC) staging system for hepatocellular carcinoma (HCC) includes all solitary tumors without vascular invasion as stage I, regardless of tumor size. The aim of this study is to determine the prognostic significance of tumor size in stage I HCC patients. METHODS: A total of 230 stage I primary HCCs were selected retrospectively. Based on univariate and multivariate analyses, clinical and pathological factors correlated with 5-year disease-free survival (DFS) and 5-year overall survival (OS) were determined. RESULTS: Univariate and multivariate analyses showed significant correlations of low serum α-fetoprotein levels (≤20 ng/ml), small tumor size (≤3 cm), wide resection margin (≥ 1 cm), and absence of cirrhotic liver with better DFS, while smaller tumor size, and wide resection margin with better OS. Of all the parameters, tumor size is the most statistically significant markers for DFS and OS. Interestingly, liver cirrhosis exerted prognostic significance in patients with small-size tumors, while resection margin exerted prognostic significance in patients with large-size tumors. CONCLUSIONS: Our results indicated that tumor size is the most important determinant of DFS and OS in resected primary stage I HCC patients. Therefore, we advocate redefining solitary tumors of ≤3 cm as T1a disease and tumors >3 cm as T1b disease. This stratification of stage I HCC patients could aid in the determination of prognosis and the development of superior protocols for patient management. However, further analysis of big registry cohorts is needed to establish a common consensus.

Expression of hypoxic marker carbonic anhydrase IX predicts poor prognosis in resectable hepatocellular carcinoma.

Carbonic anhydrase IX (CA-IX), a hypoxia marker, correlates with tumor progression in a variety of human cancers. However, the role of CA-IX in hepatocellular carcinomas (HCCs) remains largely unknown. We examined the expression of 277 unifocal, resectable, primary HCC tumors using immunohistochemistry. The CA-IX protein was expressed in 110 of the 227 (48.5%) HCC tumors. The expression of CA-IX correlated with younger age (P = 0.0446), female sex (P = 0.0049), high serum α-fetoprotein levels (P<1x10-6), larger tumor size (P = 0.0031), high tumor grade P<1x10-6) and high tumor stage (P = 1.5x10-6). Patients with HCC tumors that expressed CA-IX were more likely to have lower 5-year disease-free survival (DFS; P = 0.0001) and 5-year overall survival (OS; P<1x10-6). The multivariate analysis indicated that CA-IX expression was an independent predictor for high tumor stage (P = 0.0047) and DFS (P = 0.0456), and a borderline predictor for OS (P = 0.0762). Furthermore, CA-IX expression predicted poor DFS and OS in patients with high tumor stage (P = 0.0004 and P<1x10-6, respectively). Interestingly, CA-IX expression might contribute to the worse prognosis of female patients with advanced HCCs. Our study indicates the expression of the CA-IX protein is a crucial predictor of poor prognosis in resectable HCC, and it is also an unfavorable prognostic predictor in HCC patients with high tumor stage.

PCB levels and trends within the Detroit River-Western Lake Erie basin: a historical perspective of ecosystem monitoring.

An international workshop held in the spring of 2002 convened a group of technical experts to address monitoring, modeling, and management of PCBs within the Detroit River-Western Lake Erie basin. Participants shared and discussed a diverse set of research data bases pertaining to PCB levels within the region, discussed observed changes within different components of the local ecosystem, and identified several primary issues impacting future PCB management strategies. Results presented at the workshop indicate dramatic reductions in PCB contamination levels have been observed in much of study area between the late 1970s and mid-1990s. Estimates of loadings attributable to water and atmospheric sources have generally declined, as have PCB concentrations in herring gull eggs, smelt and walleye. Nevertheless, additional improvements have not been observed during recent years and elevated contamination levels remain a concern within local hot spots, particularly in the lower Detroit River and Trenton Channel. A primary recommendation broadly supported by workshop participants is the need to maintain, support, and coordinate a comprehensive ecosystem monitoring program for the Detroit River-Western Lake Erie basin, one that incorporates both near-field and far-field monitoring elements. Such a program is crucial to provide necessary data in support of understanding ecosystem trends, calculating annual mass loadings to the system, assessing impacts of remediation actions, developing improved modeling frameworks, and formulating cost-effective management strategies for the future.