Discussion

 Previous studies have mainly investigated the level of knowledge of dentists about prescription of antibiotic prophylaxis in infective endocarditis cases. However, this study has investigated the level of knowledge of participants about all clinical conditions requiring prophylaxis.

In this study, the target group consists of dentists and senior dental students and this is consistent with the target group in the study of Ahmadi-Motamayel et al. (3) about knowledge of endocarditis, conducted in the city of Hamadan. In contrast, Al-Hammad et al. (7) has merely investigated the level of knowledge and performance of general dental practitioners in Riyadh.

 In the study of Al-fawzan et al.(8), the knowledge of dental and medical students were compared and the knowledge levels of both groups were moderate  In the study of Ghaderi et al.(9) the level of awareness of general dentists regarding the prophylaxis for prevention of infective endocarditis was reported as moderate . In the study of Ahmadi-Motamayel et al (3). the knowledge of general dentists about dental drugs and antibiotic prophylaxis was reported as moderate , while it was at a desirable level for students and the difference was statistically significant. However, in the present study, knowledge scores were desirable in both groups of senior dental students and dentists. Apart from probability of having different levels of awareness, this inconsistency in the studies’ results may be attributed to the different design of the questionnaires, different scoring methods, considering the item of “I do not know” or the selection of various target groups as participants.

In both groups, there was no significant relationship between their knowledge scores and their gender which is consistent with the study of Zarei et al. (2) conducted in (2). In the study of AL-Hammad et al. (7), knowledge and gender had no significant relationship, too; while in the study of Ghaderi et al. (9) and in the study of Ahmadi-Motamayel et al. (3), the level of knowledge of male dentists was significantly higher than females. In contrast, in the study of Chitsazi et al. (10) the level of knowledge of female dentists was significantly higher than males.

In the present study, there was no significant relationship between the knowledge scores and the age of both groups which may be due to the low dispersion of participants’ ages. In the study of Zarei et al. (2) and study of Ahmadi-Motamayel et al.(3), knowledge also had no significant relationship with participants’ age .

In this study, there was no significant relationship between the level of knowledge and dentists’ work experience which was consistent to Al- Huwayrini et al. study (11). It showed that the acquired work experience over time, cannot improve the theoretical knowledge about the proper regimen of antibiotics or the indications of antibiotic prophylaxis in patients and the information should be refreshed by personal postgraduate studies or by participating in re-training programs.

As previously mentioned, in this study, level of knowledge of participants was investigated in three areas of systemic problems, dental procedures requiring antibiotic prophylaxis and the quality of prescription of prophylaxis regimen. In both groups, the mean scores of knowledge about the proper way of prescription of prophylaxis regimen were less than the other two items.

Most dentists participating in this study reported their textbooks as the main source of their knowledge which is consistent with the results of the study conducted by Ahmadi-Motamayel et al. (3). About fifty seven percent of dentists mentioned their participation in re-training courses and this issue may be one of the causes of desirable level of knowledge of dentists in the present study. In some previous studies (7, 9) participants were not asked about their sources of knowledge or the history of taking part in re-training programs and this can be cited as one of the strength points of this study.

The mean scores of dental students were more than dentists; however, this difference was not statistically significant. In the study of Al-fawzan et al. (8), the knowledge score of medical students was higher than dentists. However, this difference was not statistically significant, too. In the study of Roozbehani et al. (12), senior dental students and newly graduated dentists had more knowledge on principles of antibiotic prophylaxis in children with heart diseases, compared with their more experienced colleagues. This is probably due to their presence in the academic environment, easier access to scientific resources and using updated information.

Among students participating in the study, the least knowledge score was 21% and it was obtained for this question: "When we forget to use prophylaxisfor a patient on time, how much time will we have to use antibiotics effectively?" where only 13 out of 60 students chose the correct answer that is 2 hours. Among dentists, the least knowledge score was 23% and it was obtained for this question: "Does a history of rheumatic heart disease necessitate prophylaxis?” and only 14 out of 60 dentists chose the correct answer which is no. In the study of Ahmadi-Motamayel et al. (3), the least knowledge score for dentists was 7% and it was obtained for this question: "If we forget to prescribe antibiotics before dental procedures, how much time will we have to prescribe antibiotics?"(. In Sadr et al. (13) study, the question which was mostly answered wrongly by the dentists (the only group of participants in that study) was prescription of 2 g cephalexin one hour before dental practices in cases with previous allergic reaction towards penicillin.

Regarding dental procedures which needed prophylaxis (Table 2), most dentists (75%) knew that implant surgery needs prophylaxis, followed by tooth extraction (71.7%). however, 63.3% of this group thought wrongly that prophylaxis is not needed for interdental wedge placement. Most of the students knew that periodontal surgery (96.7%) and implant placement surgery (91.7%) need prophylaxis but more than two third of them (71.7%) didn’t know that subgingival scaling require prophylaxis. In Ryalat. study (14), most of the dentists (87.4%) thought that surgical tooth extractions need Prophylaxis, followed by periodontal surgery (88.2%) and implant surgery (84.3%) (14). It is better to be mentioned that in our study, tooth extraction was not divided into surgical and simple but in Ryalat study (14) this division was considered.

In the study of awareness of the most commonly systemic conditions requiring prophylaxis, both dentists (98.3%) and students (93.3%) chose prosthetic heart valves, which was consistent with the results of Ryalat and Hashemipour (14, 15) but in Al Fawzan study (8) only 32% of dental students were able to recognize that Prosthetic heart valves are accompanied with high risk of endocarditis and need prophylaxis. Interestingly, about half of the dentists in this study thought wrongly that prophylaxis is still recommended for some low-risk heart diseases such as mitral valve disease with or without regurgitation or having a history of coronary artery bypass. It may be due to the lack of updated information about new protocols of prophylaxis.

In assessment of awareness about proper antibiotic regimens for prophylaxis, more than half of the participants of both groups selected penicillin family as their first choice which was at lower level in comparison with studies of Hashemipour et al.(15) (65.8%) and Zarei et al.(2) (80%). Seventy-six percent of dentists said they would select the proper alternative antibiotics (clindamycin or azithromycin) when patients were allergic to penicillin, while this result was 80% in students which was not significantly different. This could be due to frequent mentioning of this subject in different dentistry textbooks over and over during academic education. In the study of Hashemipour et al. (15), Students' knowledge about this subject was more than two-folds in comparison with the knowledge of dentists. In the study of Zarei et al. (2), only 30% of participants were aware of proper alternative antibiotics in allergic cases (2).

Among students participating in the present study, the highest knowledge score was 96.7% and it was obtained for this question: "Does periodontal surgery require antibiotic prophylaxis?" and 58 out of 60 students chose the correct answer. Among dentists, the highest knowledge score was 98.3% and it was obtained for this question: "Does a patient with a history of prosthetic heart valve need antibiotic prophylaxis before dental procedures?" and 59 out of 60 dentists chose the correct answer which is yes.

In the students group, the minimum score (21%) was gained for this question: "If in a patient who requires prophylaxis, you forgot to prescribe antibiotics before a dental procedure, how long after the treatment, the use of antibiotics would be effective? Only 13 out of 60 students selected the correct answer: 2 hours later. In the dentists group, the minimum score of knowledge was 23%, which was related to this question: “Does a patient with a history of heart rheumatism require prophylaxis?” Which only 14 out of 60 dentist had selected No as the correct answer. In the study of Ahmadi- motemayel et al. (3), the minimum score for knowledge in the dentists group was 7% and it was related to this question: "If antibiotic prescription is forgotten, how long can antibiotics be prescribed after dental treatment?" Which was consistent with our students group.

Despite the desirability of the level of knowledge of senior dental students and dentists in the city of Yazd, due to the importance of antibiotic prophylaxis in specific clinical conditions and in some dental procedures, it is suggested to hold training courses on this subject and to organize effective re-training programs in order to improve the knowledge or to update the information of dentists. Obviously, these scientific data exist systematically on medical information data bases; so, facilities such as easy access to high-speed Internet network can be beneficial for general dental practitioners in health centers.

 Considering the importance of this issue, it is suggested to investigate the level of knowledge of dentists and physicians in other health centers of Yazd to address possible shortcomings.Data were collected using questionnaires and some general dentists did not cooperate well in the completion and delivery of questionnaires and this was one of the limitations of this study.

Conclusion

The levels of knowledge of senior dental students and general dentists about the proper way of prescription of prophylactic antibiotics regimens for special systemic conditions and dental procedures were desirable and this might be due to the participation of dentists in relevant re-training courses and allocation of educational resources to this area.

 Acknowledgment

This study was supported by Shahid Sadoughi University of medical sciences.