Dental Education Research Articles

KNOWLEDGE, ATTITUDE, AND PRACTICE REGARDING ARTIFICIAL INTELLIGENCE (AI) AND ITS USAGE IN DENTAL ACADEMICS CURRICULUM AMONG DENTAL UNDERGRADUATES AND POSTGRADUATES

Background: Artificial intelligence (AI) is increasingly being recognized for its potential to revolutionize dental education and practice. However, the extent of knowledge, attitudes, and practices (KAP) regarding AI among dental undergraduates and postgraduates remains underexplored. Objectives: This study aims to assess the knowledge, attitudes, and practices related to AI and its integration into the dental academic curriculum among dental undergraduates and postgraduates. Methods: A cross-sectional questionnaire-based study was conducted among 545 participants, including final-year dental undergraduates and postgraduate dental students . The structured questionnaire covered demographics, knowledge of AI, attitudes towards its integration into dental education, and current practices involving AI. Results: The study found significant variations in knowledge levels, with postgraduates demonstrating a more comprehensive understanding of AI applications in dentistry compared to undergraduates. Attitudes towards AI were generally positive across both groups, with participants recognizing its potential to enhance diagnostic accuracy and streamline administrative tasks. However, there were concerns about the reliability of AI systems and the potential for reduced human oversight. Practical application of AI was limited, particularly among undergraduates, highlighting a gap between theoretical knowledge and practical use. Conclusion: The study underscores the need for integrating comprehensive AI education into the dental curriculum, encompassing both theoretical knowledge and practical training. Continuous professional development and a balanced approach to AI use in dental practice are essential to prepare future dental professionals for an AI-driven healthcare landscape. Gender-wise, the survey reveals consistent support across male and female dental professionals for AI's potential in enhancing dental research, with minimal variation in beliefs. KEYWORDS: Artificial intelligence, dental education, knowledge, attitudes, practices, dental undergraduates, postgraduates.

KNOWLEDGE, ATTITUDE AND PRACTICE AMONG DIFFERENT DENTISTS REGARDING ORAL PIERCING DELETERIOUS EFFECT: A QUESTIONNAIRE BASED STUDY

Background: Oral piercings, including tongue, lip, and cheek piercings, are popular forms of body modification. These piercings, while culturally significant and a means of self-expression, pose various health risks that necessitate informed management by dental professionals. Objectives: This study aims to assess the knowledge, attitudes, and practices (KAP) related to oral piercings among dental undergraduates, postgraduates, and practicing dentists. Methods: A cross-sectional questionnaire-based study was conducted among 300 participants, comprising dental undergraduates, postgraduates, and practicing dentists. The questionnaire covered demographics, knowledge of oral piercings, attitudes towards these modifications, and clinical practices in managing complications. Data were analyzed using SPSS software, with descriptive statistics and comparative tests (Chi-square and ANOVA) applied to evaluate KAP differences among the groups. Results: Significant variations in knowledge levels were observed, with practicing dentists displaying the highest understanding of oral piercings and their complications. Postgraduates demonstrated a more comprehensive knowledge compared to undergraduates, who showed a basic understanding. Attitudes towards oral piercings varied, with undergraduates and postgraduates viewing them more favorably compared to the cautious stance of practicing dentists. Clinical practices also differed, with experienced dentists more proactive in patient education and management strategies. Conclusion: The study highlights the need for enhanced education on oral piercings across all levels of dental training. Integrating comprehensive curricula and continuous professional development programs can bridge knowledge gaps and improve clinical practices. Gender-wise analysis highlights that both male and female dental professionals show comparable levels of awareness and engagement regarding oral piercings, with responses indicating a shared commitment to patient education and proactive care practices in managing associated risks and complications KEYWORDS: Oral piercings, dental education, knowledge, attitudes, clinical practice, complications.

A comprehensive dataset of annotated oral cavity images for diagnosis of oral cancer and oral potentially malignant disorders

ObjectivesThis study aims to address the critical gap of unavailability of publicly accessible oral cavity image datasets for developing machine learning (ML) and artificial intelligence (AI) technologies for the diagnosis and prognosis of oral cancer (OCA) and oral potentially malignant disorders (OPMD), with a particular focus on the high prevalence and delayed diagnosis in Asia. Materials and methodsFollowing ethical approval and informed written consent, images of the oral cavity were obtained from mobile phone cameras and clinical data was extracted from hospital records from patients attending to the Dental Teaching Hospital, Peradeniya, Sri Lanka. After data management and hosting, image categorization and annotations were done by clinicians using a custom-made software tool developed by the research team. ResultsA dataset comprising 3000 high-quality, anonymized images obtained from 714 patients were classified into four distinct categories: healthy, benign, OPMD, and OCA. Images were annotated with polygonal shaped oral cavity and lesion boundaries. Each image is accompanied by patient metadata, including age, sex, diagnosis, and risk factor profiles such as smoking, alcohol, and betel chewing habits. ConclusionResearchers can utilize the annotated images in the COCO format, along with the patients’ metadata, to enhance ML and AI algorithm development.

Bridging the Gap: Dental Students' Attitudes toward Persons with Disabilities (PWDs).

Persons with disabilities (PWDs) face significant barriers in accessing dental care, resulting in poorer oral health outcomes compared to the general population. To reduce dental healthcare disparities, dental professionals must develop positive attitudes and acquire the necessary skills to treat PWDs effectively. This study aimed to assess the experiences, education, training levels, and attitudes of dental students and interns toward PWDs, and to explore the relationships between their exposure to PWDs, their education/training regarding managing PWDs, and their attitudes toward PWDs. Participants were recruited using convenience sampling. From May to June 2023, a pretested, validated online questionnaire (developed based on existing survey instruments and modified to fit the study context) was distributed to 98 eligible dental students and interns at King Faisal University. Descriptive and analytical statistics were used for analysis. The response rate was 88.78%. There was a statistically positive correlation between students' exposure to PWDs and their attitudes (p < 0.05). Statistically significant relationships were found between students' education/training and their attitudes towards educational experiences and instructors (p < 0.01) and interpersonal interactions with PWDs (p < 0.05). No statistically significant relationship existed between the year of study and future encounters with PWDs (p = 0.176). Additionally, 42.5% of students felt inadequately prepared to treat PWDs, and 88.5% expressed a desire for further education. Notably, 20.7% reported no training on PWDs, while 70.1% preferred clinical education. The study underscores the importance of exposure and training in shaping dental students' attitudes toward PWDs. Dental schools should prioritize structured teaching, greater contact with the disabled community, and hands-on experiences to ensure dental professionals are both well prepared and positively inclined to treat PWDs. These findings have significant implications for improving dental education curricula.

Readiness for clinical practice: Self-perceived confidence of final year dental students in Turkey - A multi-institutional study.

The primary aim of undergraduate dental education is to prepare dental students for independent dental practice and to enable them to provide safe and effective dental care. This study aimed to investigate the self-perceived preparedness of senior dental undergraduate students in Turkey. Purposive sampling was used to recruit final-year dental students from 10 dental institutions offering undergraduate dental programs in Turkey. Student preparedness was assessed using a previously validated dental preparedness assessment scale based on 50 items encompassing core clinical skills, cognitive attributes, and behavioral skills. The research instrument was then translated into Turkish. The R statistical environment for Windows was used for the data analysis. Responses were provided by 272 students (156 women and 116 men; 57% and 43%, respectively) across 10 different universities. The mean score of the participants was 75.68 with slightly higher scores for men compared to women (77.35 vs. 74.46 respectively). However, independent t-tests showed that the scores did not differ significantly between women and men. This study evaluated the self-perceived preparedness for dental practice of final-year students from 10 universities in Turkey. Although the results showed several areas of weakness, the scores of self-perceived preparedness of Turkish students were comparable to those reported in Europe and Asia. These findings can be used to inform future curriculum development to support students in consolidating their learning in perceived areas of weakness.

Dental Notation System Used in Dental Teaching in Different Dental Collages

The aim of this study was to find the most commonly used Tooth Numbering System to teach and learn in dental collages in various universities (Benghazi University, Omar Mukhtar University and Libyan International Medical University) by both academic staff and fourth year dental students, to identify the most commonly taught TNS in different dental colleges, to understand the reason why dental staff prefer to use a specific TNS, and the consequences of using more than one TNS. This cross-sectional study was conducted within the dental collages of various Medical Universities. The questionnaire containing 11 questions was randomly distributed to 120 individuals (60 deans of academic staff and 50 fourth year dental students). The palmer notation system was the most commonly used to teach and learn by academic staff and dental students in teaching and practiced in dental collages, while the universal notation system was the least used to teach and learn by academic staff and dental students. As well as the most TNS preferred to use by academic staff and dental students in operative, oral surgery departments and orthodontic department in academic teaching was the palmer notation system while the least TNS use was universal notation system. The Palmer TNS proved to be the most taught TNS in dental colleges in different University. It is advised that the Palmer TNS be implemented as a unified system in my country, due to the advantages of this particular TNS and the benefits of using one single TNS.

Artificial intelligence, ChatGPT, and dental education: Implications for reflective assignments and qualitative research.

Reflections enable students to gain additional value from a given experience. The use of Chat Generative Pre-training Transformer (ChatGPT, OpenAI Incorporated) has gained momentum, but its impact on dental education is understudied. To assess whether or not university instructors can differentiate reflections generated by ChatGPT from those generated by students, and to assess whether or not the content of a thematic analysis generated by ChatGPT differs from that generated by qualitative researchers on the same reflections. Hardcopies of 20 reflections (10 generated by undergraduate dental students and 10 generated by ChatGPT) were distributed to three instructors who had at least 5 years of teaching experience. Instructors were asked to assign either 'ChatGPT' or 'student' to each reflection. Ten of these reflections (five generated by undergraduate dental students and five generated by ChatGPT) were randomly selected and distributed to two qualitative researchers who were asked to perform a brief thematic analysis with codes and themes. The same ten reflections were also thematically analyzed by ChatGPT. The three instructors correctly determined whether the reflections were student or ChatGPT generated 85% of the time. Most disagreements (40%) happened with the reflections generated by ChatGPT, as the instructors thought to be generated by students. The thematic analyses did not differ substantially when comparing the codes and themes produced by the two researchers with those generated by ChatGPT. Instructors could differentiate between reflections generated by ChatGPT or by students most of the time. The overall content of a thematic analysis generated by the artificial intelligence program ChatGPT did not differ from that generated by qualitative researchers. Overall, the promising applications of ChatGPT will likely generate a paradigm shift in (dental) health education, research, and practice.

Shaping tomorrow’s dentists: a multi-institutional survey of undergraduate dental students’ perceptions towards interprofessional education

BackgroundInterprofessional education (IPE) is essential to foster collaboration among healthcare professionals for holistic patient care. However, Malaysian dental education remains discipline-centric, hindering multidisciplinary learning approaches. Hence, this study aimed to explore Malaysian undergraduate dental students’ perceptions of IPE.MethodsThe present cross-sectional study employed convenience sampling to survey undergraduate dental students from four Malaysian institutions using a modified questionnaire with 20 close-ended and 2 open-ended questions. The questionnaire covered three domains (effectiveness, preference, importance) to assess students’ perceptions using a five-point Likert scale. Psychometric validation was performed to assure validity and reliability of the modified questionnaire. Quantitative analysis (descriptive and inferential statistics), and qualitative analysis (content analysis) were subsequently performed.Results397 students responded, and positive perceptions were generally noted with mean scores ranging from 4.13 to 4.35 across all domains. Questions 2 and 3, assessing the improvement in understanding the roles and responsibilities, and communication among healthcare professionals, received the highest mean scores. Meanwhile, Question 15 concerning the incorporation of IPE into educational goals received the lowest mean score. Regression analysis identified gender and clinical phase as significant factors, with females and preclinical students exhibiting more favourable perceptions. Motivators for IPE included a keen interest in diverse perspectives and recognising the importance of teamwork, while barriers encompassed tightly packed schedules, lack of understanding about IPE, misconceptions regarding dental education, and students’ nervousness and fear of participation.ConclusionThis study produced a valid and reliable instrument to measure undergraduate dental students’ perceptions towards IPE. Strategic planning, such as overcoming logistical challenges, improving awareness, and creating a supportive learning environment are crucial for successful IPE integration into existing curricula, especially in resource-constrained developing countries like Malaysia.

Exploring Faculty Preparedness for Artificial Intelligence-Driven Dental Education: A Multicentre Study.

Introduction In the modern era, technology, including artificial intelligence (AI), is the centre of digital innovation. AI is revolutionising numerous fields, including the healthcare sector, globally. Incorporating AI in dental education may help in improving the diagnostic accuracy, learners' experiences, and effectiveness of the management of dental education institutions. However, successful implementation of AI requires the faculty's willingness to incorporate it into their practices. Thus, this research aims to explore the readiness of faculty members to integrate AI into dental education. Methodology The study employed a qualitative exploratory design to gather in-depth insights into faculty readiness for AI-driven dental education. Purposive sampling was employed, and 21 faculty members from public and private dental colleges in South Punjab participated in semi-structured interviews. The interviews focused on understanding participants' perceptions, experiences, and challenges related to AI integration in dental education. Thematic analysis was conducted utilising Braun and Clarke's framework to identify key themes and subthemes from the qualitative data using inductive coding. Results Five major themes and 14 subthemes emerged from the data analysis. Faculty members had low AI literacy coupled with diverse perceptions; some participants perceived AI as a solution for revolutionising teaching and learning, while others criticised its misuse as academic misconduct by students, an effect on students' critical thinking, and a threat to conventional jobs. However, most of the respondents also considered AI beneficial for students with remote access or from marginalised populations in terms of accessing and learning from limited resources. Concerns that participants highlighted included a lack of training opportunities, limited facilities, ethical concerns pertaining to data privacy, and assessment bias. Some of the recommendations provided by the respondents include the provision of training opportunities, the allocation of resources and infrastructure, and continuous effective support from institutions for the integration of AI in dental education. Conclusions This study emphasised the readiness of the faculty when it comes to the integration of AI in dental education. The faculty considered AI favourable for digitization and innovative education, although there is a lack of awareness of its application. Regarding the benefits of utilising AI, respondents highlighted its quick response, prediction of students' performance, and flexibility in learning. The challenges included lack of awareness regarding its implementation, inadequate training, lack of availability of resources, lack of institutional support, the problem of data confidentiality, and resistance to change. Suggestions included the provision of technical support, skills training, and the provision of required infrastructure. Participants recommended that AI tools must incorporate cultural and contextually specific content, use technical support for problems, and incorporate constant response systems to improve the AI tools for novice users, especially within developing regions such as Pakistan.

Effectiveness of error-based active learning compared to conventional lecture-based method among undergraduate dental students: A randomized controlled trial.

Dental education assumes an indispensable role in adequately equipping students for a successful career in dentistry. Error-based active learning, an innovative approach in dental education, is a combination of mistake-driven learning (MDL) and case-based learning (CBL) to provide a transformative learning atmosphere for students. While active learning has gained popularity in dental education, the effectiveness of error-based active learning remains unexplored. This study aims to evaluate the effectiveness of error-based active learning among final-year dental undergraduate students in comparison with the conventional lecture-based approach. A parallel-arm single-blind randomized controlled trial was conducted in a dental institute in India from November 2022 to December 2022. A total of 74 students were randomly allocated to two groups: Group A (n = 37) received error-based active learning and group B (n = 37) received conventional lecture-based learning approach. Atraumatic restorative treatment (ART) was chosen as the topic for the study. The knowledge of students was assessed at three intervals: baseline, post-intervention, and 4 weeks after the intervention, using a self-designed and validated questionnaire with Cronbach's alpha of 0.87 and a content validity ratio of 0.84. A standard survey questionnaire was employed to evaluate students' perceptions of the teaching methods. Error-based active learning group outperformed the lecture-based group significantly in the post-intervention test (20.92 ± 1.42 vs 16.97 ± 3.06), with better knowledge retention (18.30 ± 2.02 vs 14.05 ± 4.26) and positive feedback from the students. The error-based active learning approach proved superior to the conventional lecture-based method in enhancing and retaining knowledge regarding ART.

Exhibit 9: ADEA principles for accreditation in dental education: (As approved by the 1997 ADEA House of Delegates).

Exhibit 9: ADEA principles for accreditation in dental education: (As approved by the 1997 ADEA House of Delegates).

Assessing Emotional Intelligence among Dental Undergraduate Students: An Institutional Insight from Western India in the Postpandemic Context

Abstract Background: Emotional intelligence (EI) plays a pivotal role in academic success, especially in challenging fields such as dentistry. The COVID-19 pandemic has revolutionized education, necessitating a fresh examination of EI among dental students in the postpandemic era. Materials and Methods: This cross-sectional study involved undergraduate dental students and employed a structured questionnaire comprising 21 questions to assess EI, gather demographic data, and explore learning behaviors. The gathered data underwent rigorous statistical analysis using SPSS, including Chi-square tests. Results: Among the 525 students, 168 participated, representing a 32% response rate. Notably, the majority of respondents were female (67%) and exhibited EI scores predominantly in the moderate range. Significantly, the study revealed noteworthy correlations between EI and family income (P = 0.03*) and study hours (P = 0.00*). However, no substantial link was identified between EI and work completion behavior. Discussion: This study illuminates the intricate relationship between EI, socioeconomic factors, and study habits within the context of dental education. It implies that greater family income and increased study hours positively influence EI. The practical implications extend to tailored EI programs and addressing educational disparities. Conclusion: This study significantly advances our comprehension of EI among dental students. It underscores the relevance of EI in dental education and advocates for equitable educational strategies in a post-COVID landscape.

Impact of E-Learning and Predictable Practical Learning Expectations During the Covid-19 Pandemic on Dental Graduates

ABSTRACT Background: Dental education is facing hitherto unheard-of difficulties as a result of the COVID-19 epidemic, which calls for quick adaption to remote learning methods. The purpose of this study was to look at how dental graduates were affected by the COVID-19 epidemic and the effects of e-learning and predictable practical learning expectations. Methods: Data from dental college graduates were gathered using a mixed-methods approach that included questionnaires and interviews. While surveys evaluated e-learning’s perceived efficacy, obstacles faced, and levels of satisfaction, interviews offered a deeper look into the opinions and experiences of participants. Findings: Graduates in dentistry expressed great satisfaction and perceived efficacy with e-learning platforms. Nevertheless, difficulties were faced, such as inadequate practical expertise and technological obstacles. Expectations related to practical learning, such as training predictability and availability of clinical resources, markedly declined throughout the epidemic. Conclusion: In summary, the results underscore the intricate relationship among e-learning, realistic learning objectives, and the difficulties encountered by recent dentistry graduates during the COVID-19 epidemic. Assuring thorough dentistry education in the post-pandemic period requires a hybrid strategy that incorporates virtual and practical learning modalities.

The application of a virtual rubber dam isolation training system in dental preclinical education

ObjectiveTo assess the efficacy of a virtual rubber dam isolation training system in enhancing preclinical dental education. MethodsA total of 28 Grade 4 undergraduate dental students were randomly divided into two groups: a virtual simulation priority group and a conventional phantom-head priority group. The virtual simulation priority group underwent virtual simulation training initially, followed by conventional phantom-head training. Conversely, the conventional phantom-head priority group received traditional training first, subsequently followed by virtual simulation training. Pre- and post-training theoretical knowledge examination were administered, and a practical ability assessment was conducted after the second theoretical examination. A questionnaire survey was also conducted to gauge students’ attitudes and satisfaction towards the training process. ResultsAfter training, both groups exhibited significantly higher mean scores of theoretical knowledge examination compared to their baseline scores (P < 0.001). Notably, the virtual simulation priority group achieved significantly higher average scores than the conventional phantom-head priority group (P < 0.001,Cohen's d = 1.778). However, there was no significant difference in the mean time taken to complete the practical ability assessment between the two groups (P>0.05,Cohen's d = 0.19). Furthermore, the majority of students (96.4 %) strongly agreed that the virtual rubber dam isolation training enhanced their comprehension of the knowledge. 92.9 % of the students strongly agreed that the virtual training system improved their abilities of mastering the rubber dam isolation technique. Only two students (7.1 %) expressed neutrality regarding the virtual simulation effectiveness. ConclusionsThis study showed that the virtual rubber dam isolation training was useful in the preclinical skills training. The integration of virtual simulation into the curriculum, particularly when prioritized over conventional methods, has shown promising results in enhancing students' theoretical knowledge and technical skills related to rubber dam isolation.

Journal of Dental Education Volume 88 Number Supplement 2/July 2024

Journal of Dental Education Volume 88 Number Supplement 2/July 2024

Exhibit 5: Members of American Dental Education Association Committees, Representatives to Other Organizations, and Fellows, March 2023-March 2024.

Exhibit 5: Members of American Dental Education Association Committees, Representatives to Other Organizations, and Fellows, March 2023-March 2024.

Bylaws of the American Dental Education Association: (With changes approved by the 2024 House of Delegates).

Bylaws of the American Dental Education Association: (With changes approved by the 2024 House of Delegates).

Perception towards professionalism among Indian dental educators and residents – A descriptive study

Background: Lack of professional integrity among dental students can greatly impact the safety of future patients. Currently, there are no established learning outcomes for dental professionalism. Aim: The aim of the study is to assess the perceptions of Indian educators (DE) and residents (DR) towards the attributes and methods to learn/teach dental professionalism. Materials and Methods: A cross-sectional descriptive study was conducted among Indian DE and DR from April 1, 2022, to July 31, 2022. A 31-item questionnaire was developed to evaluate the demographic data, perceptions of learning/teaching methods, and attributes of professionalism. The sample size was calculated to 446 subjects. Descriptive statistics were carried out. Results: Of the 428 participants, 287 were DE and 141 were DR. Most participants are aware of the attributes and have a positive attitude toward professionalism. Role modeling and mentoring were the most effective ways to learn professionalism. About 97.9% of DE and 97.9% of DR felt it was important to teach dental students about professionalism. About 85.7% of DE and 73% of DR felt the need for an additional program in the current BDS curriculum. Most participants selected contact with role model teachers, clinical experience with patients, and discussion with peers as methods by which they learned dental professionalism. Conclusion: The majority of the participants are aware and have a positive attitude toward dental professionalism.

Knowledge, attitude, and practice study of pharmacovigilance in a dental teaching institute in Western India

ABSTRACT Background: India started the National Programme of Pharmacovigilance in 2005, which was renamed as Pharmacovigilance Programme of India in 2010. This is the main portal for detecting and reporting the adverse effects of drugs. Aim: This study aimed to evaluate the knowledge, attitude, and practice (KAP) of pharmacovigilance (Pv) in a dental teaching institute in Western India. Materials and Methods: The KAP questionnaire regarding Pv was distributed among the dental faculties. The knowledge-based questions were corrected and the scoring was given as excellent knowledge, good knowledge, fair knowledge, and poor knowledge for the scores between 0–5, 6–10, 11–15, and 16–20, respectively. Descriptive statistical analysis was performed which is presented as frequencies (n) and percentages (%) in all three sections of the questionnaire. Results and Observations: The knowledge of 24 (44%) participants was found to be fair with scores between 6 and 10. The knowledge of 23 (42%) participants was found to be poor with scores between 0 and 5 and the knowledge of 8 (14%) participants was found to be good with scores between 11 and 15. A positive and promising attitude was exhibited by the dental faculties toward reporting adverse drug reactions (ADRs). Only two study participants had reported an ADR event. Conclusion: The deficiencies in knowledge appear to be the underlying factor for the underreporting of adverse reactions encountered by dental practitioners.

Occupational percutaneous injuries and exposures at a dental teaching institution from 2017 to 2023

Background: All dental professionals face the risk of occupational percutaneous injuries and exposures. Previous studies have reported high incidents of percutaneous injuries among dentists. This study examined injury data over six years at a large teaching institution for trends to increase awareness and to design appropriate interventions to reduce injury rates. Method: Study injury data was collected for the department of employee and occupational health. The data was entered into an electronic incident reporting system from 2017-2023. Statistical analysis was performed with Openepi to determine injury trend by year and overall association by activity type. Result: There was a total of 168 injuries reported between 2017 and 2023. A majority of the injuries (54%) were caused by a needle or sutures followed by instruments at 41%. Most of the injuries (44%) occurred during treatment and while cleaning the surgical spaces at 15%. Only 13% of the injuries were attributed to handling or recapping needles. Chi-square test 0.2618 (p&gt;.05) indicated there was no significant difference between years and number of injuries. Overall chi-square p ( &lt; 0 .001) by activity type was significant indicating risk was not equal across all activities. Conclusion: Injuries declined during COVID-19 but soared back up in 2023. Needles, sutures, and instruments were the predominant source of injuries. Injuries occurred during treatment (43%), while cleaning the surgical space (15%) and while recapping or handling needles (13%). This study is the first step in understanding the trend and factors attributing to injuries to implement appropriate corrective actions. Further analysis should be conducted to identify specific procedures or clinical activities exposing employees to Occupational percutaneous injuries.