Factors influencing international and U.S. dentists’ interest in advanced periodontal education: a pilot study

Background The enrollment of international periodontal students in U.S. dental schools has been increasing in recent years. Interest in applying to a periodontics specialty program may differ between U.S and international dental school graduates. The purpose of this study is to assess, from the perspective of periodontal residents, (1) factors that interest dental students to apply to periodontics programs and (2) differences in background and interest between U.S and international graduates. Methods A 20-question survey was sent out electronically to periodontics residents. The survey questions were designed to obtain information on the participants’ backgrounds, factors that influenced them to specialize in periodontics, and their preferred features of graduate periodontics programs. The data were analyzed using descriptive statistics for socio-demographic variables, a Wilcoxon two sample test to compare mean Likert scale scores, and Fisher’s exact test for associations between comparison groups. Results Of the two hundred residents invited to participate, 28% responded. The majority of the respondents stated that interest in implantology, previous exposure to periodontal procedures, interest in improving periodontal surgery skills, a good relationship with periodontics faculty, the residency curriculum, advanced program and faculty reputation as influencing factors in selecting periodontics as specialization. The majority of international graduates have up to $50,000 dollars in student debt; by comparison, half of the domestic graduates have a debt of over $250,000 dollars (p ≤ 0.05). Working experience as a dentist was significantly greater among international residents (73%) in comparison to U.S graduates (32%). In contrast with international graduates, U.S graduates more frequent reported that good relationships with the periodontics predoctoral faculty contributed to their interest in periodontics (p ≤ 0.05). Program cost and location had a greater impact on the decision of U.S. graduates than international graduates (p ≤ 0.05). Conclusions Overall, factors associated with personal finance and predoctoral education have a greater impact on the decision of American graduates than international graduates to pursue an advanced education in periodontics, which may influence the increased enrollment of international students.


Background
Fifty-five university-and hospital-based graduate periodontics programs exist in the United States. Forty-five programs admit international students who do not have a U.S dental license. According to the American Dental Association (ADA)'s annual Survey of Advanced Dental Education and the Council on Dental Education and Licensure (CDEL), the number of enrolled international periodontal students in U.S. dental schools increased from 2012 to 2018. In the graduating class of 2012, 27% of graduates from advanced programs in periodontics were international students, compared to 33% in 2020. Moreover, the number of programs accepting international students increased from 39 programs (2012) to 47 programs (2020). However, the percentage of international students who enrolled in other specialties such as endodontics and prosthodontics has remained almost stable [1].
In our previous study, from the periodontics department chairpersons' perspectives reported by Luke Hearty et al., specialty clinic rotations and elective courses appear to increase student interest in a periodontal residency program. Periodontal residencies that offer externships had a greater number of candidates. However, factors such as residency stipends and fellowships did not have great influence on dentist interest in a periodontal program [2]. Data from a survey on graduating dental students, suggested that mentoring influenced students interest in residencies, indicating the significance of exposure to the advanced program educators and residents [3]. Nevertheless, in another study in the U.S., it was reported that graduating dental students with a debt of at least $100,000 were more likely to start practicing dentistry after graduation than students with lower debt, even after adjusting for the impact of individuals who were influential on students' career decisions [4].
Differences between dental students in terms of social, economic and cultural backgrounds are expected to influence their career plans. Surveyed dental students from different Middle Eastern nationalities in a Jordan Dental school agreed on most factors affecting their choice of a specialty, except for the reputation of the specialty [5]. Authors of a student survey conducted in one dental school in U.K. reported that "having a talent in the field" had the largest positive influence on pursuing a specialist career [6]. Saudi Arabia dental students reported that the influence of family members in the dental profession, and specific interest in patient population as significant factors in choosing a specialty. Other important factors were variety of non-clinical duties, and research opportunities [7].
Interest in applying to a periodontics specialty program may differ between U.S and international dental school graduates. The aim of this study is to assess the perspective of periodontal residents regarding (1) factors that attract dental students to apply to periodontics programs and (2) differences in background and interest between U.S and international graduates.

Participants
The research protocol for this study was approved by the Case Western Reserve University Institutional Review Board as exempt from oversight (IRB-2018-1242). The survey was carried out in accordance with relevant guidelines and regulations. In 2018, a 20-question survey (Table 1) was sent out electronically to periodontics graduate program residents. The survey was placed on the Surveymonkey website and the link to participate in the survey was sent out to 200 residents, who were student members of the American Academy of Periodontology (AAP) and were enrolled in a residency program. The survey contained a cover letter explaining its purpose, how the data would be used, stated that the data would be anonymous. The request to participate in the survey was sent three times by e-mail in 30-day intervals. Respondents completed the survey anonymously and voluntarily.

Study questionnaire
The survey included questions that were dichotomous, had multiple choices, or had a 5-point Likert scale (1 = strongly disagree to 5 = strongly agree). Some of the standardized survey questions were derived from previous investigations [3,8], and others were created to address research objectives. The modified survey questionnaire was pilot tested among colleagues of the authors to validate questions before it was uploaded online.
The survey questions were framed to obtain information related to the participants' socio-demographic characteristics, factors in selecting periodontics as an area of specialization (interest in periodontal surgeries, interest in implantology, previous exposure to periodontal surgeries, previous positive interactions with periodontal faculty, periodontology courses in dental school, and previous externship/fellowship), and the preferred graduate periodontics program features (location, cost, curriculum, faculty reputation, and research opportunities). Previous experience before enrolment in the periodontics program and goals after completion of the program was also surveyed.

Statistical analysis
The data were analyzed using IBM SPSS software version 27, with descriptive statistics on socio-demographic variables; Chi-square analysis and/or Fisher's exact test was performed to test associations between socio-demographic variables and previous experiences in dentistry and research among International and US graduates; and a non-parametric Wilcoxon two sample test was done to compare mean Likert scale scores on factors influencing advanced periodontal education and future prospects among US and International graduates. The statistical significance for all tests was set at p < 0.05.

Results
A total of 58 (28%) invited residents responded to the survey. About 50% of respondents were between 30 and 40 years of age and had less than $50,000 in educational debts prior to their attendance in the residency program, and 78% were male with 65% having graduated from an accredited dental school in the U.S ( Table 2).
The majority of international graduates' (60%) were between the ages of 30 and 35 years that was significantly (p ≤ 0.05) different with only 37% of the U.S graduates in this age category. The majority of the international graduates (70%) had no educational debt and in comparison, it was significantly different (p ≤ 0.05), with approximately 21% of US graduates had incurred an educational debt less than $150,000, and 50% had a debt greater than $150,000 dollars ( Table 2).
The distribution of respondents' dental-associated experience prior to the periodontics residency included 19% with a Master's or PhD training, 24% with research experience, 22% with advanced training in general dentistry, 38% with an externship/fellowship, and approximately 45% had prior experience practicing dentistry. The response rates for working as a general dentist prior to residency enrollment was significantly (p ≤ 0.05) different between international (70%) and U.S. graduates (32%) ( Table 3).
Survey responders answered questions on factors that may influence the selection of periodontics as an area of specialization. The majority of the respondents stated that interest in implantology, previous exposure to periodontal procedures, interest in improving periodontal surgery skills, and a good relationship with periodontics faculty as influencing factors in selecting periodontics as an area of specialization (Table 4). International students were significantly less frequent than U.S. graduates to Table 1 Survey questionnaire Please answer all questions to the best of your knowledge and ability Please respond to the statements below that represent preferred graduate program features associated with choosing advanced periodontal education; with a score on a scale of 1 to 5, [1 = Strongly disagree; 2 = Disagree; 3 = Neutral; 4 = Agree; and 5 = Strongly Agree] 9. I am familiar with the curriculum contents of this particular program that you are in currently 10. The program and faculty member reputation was important to me 11. Cost of attending the program was a significant factor to be considered for me 12 report that the reason they chose the field of periodontics was due to a positive relationship with a periodontics faculty member (p ≤ 0.05). Moreover, unlike U.S. graduates, international graduates reported that the completion of a periodontics program was one way to obtain a dental license to practice in the U.S.; this influenced their interest in periodontics (p ≤ 0.05) ( Table 4).
The majority of the respondents agreed on the importance of the influencing factors associated with the program characteristics, such as the curriculum, the program and faculty reputation. However, in selecting a residency, cost and location had a greater impact on the decision of U.S. graduates than international graduates (p ≤ 0.05) ( Table 5).
U.S. and international graduates had similar interests pertaining to their future plans. Yet, international graduates were more interested in holding a part-time (40%) academic position than were U.S. graduates (15%) (p ≤ 0.05). One-third of the international graduates reported that they intend to practice dentistry in their home country (Table 6).

Discussion
In the present study, from the perspective of periodontics residents, interest in undertaking a graduate periodontics program is shared among U.S and international graduates. Overall, the majority of respondents stated that interest in implantology, previous exposure to periodontal procedures, interest in improving periodontal surgery skills, a good relationship with periodontics  faculty, the residency curriculum, advanced program features and faculty reputation as factors that attract dental graduates in selecting an advanced periodontics program. One of the top influential factors was previous exposure to periodontal procedures. This result is in agreement with our previous study, which was reported in the opinion of periodontics department chairmen that specialty clinic rotations and elective courses increase student interest in applying to advanced periodontal education [2]. However, there were differences between U.S. and international graduates in terms of background and factors that influenced them to commit to further education in periodontics,   In the U.S., the average educational debt for a dental student was $292,000 in 2019 [9]. This is in agreement with the present study, where a significantly higher proportion of U.S. dental graduates, had educational debts greater than $150,000 as compared to international graduates. According to the present survey, in comparison to American graduates, international graduates tend to be older and have more work experience as a general dentist prior to attending a periodontics program, which may contribute to their having less debt. Furthermore, international graduates frequently have financial support from their home country's government for higher education. In agreement with the present study, student debt [3,4,8,10], program cost [11] and location [12,13] have been reported as significant factors that influenced the students' decision to specialize in dentistry. In the U.S., the average income for general dentists is lower than that of dental specialists [14]. However, American students may be drawn to this career choice by the ability to enter the workforce earlier. Interestingly, in our previous study, from the perspective of program chairmen, the offering of a stipend does not affect the number of applications to the periodontics programs [2]. Perhaps the increasing numbers of international students in dental higher education over time may be due to the fewer financial responsibilities compared to the U.S. graduates' financial burden.
In the present study, in comparison to international graduates, U.S. graduates reported that a good relationship with the pre-doctoral faculty had a positive impact on developing interest in a periodontics program. This result ties with a previous study wherein it was found that strong faculty student interaction tended to foster interest in a career in periodontics [15]. In agreement, prosthodontics residents reported that advice from predoctoral mentors was an important influential factor in choosing prosthodontics as a career [16]. However, in a Saudi Arabian study, students reported that the influence of family members in the dental profession are of high importance in a selection of a specialty [7]. This variance in opinions among international and American graduates may be influenced by differences in cultural backgrounds. For example, it has been reported that prestige is an important influential factor on choosing a specialty for Turkish, Saudi and Iranian dental graduates. However, it is not an essential factor for western dental graduates, such as British and Danish [6,[17][18][19]. Interestingly, in the present study, international graduates reported that completion of a periodontics program was one way to obtain a dental license to practice in the United States.
Also, approximately 30% of international graduates had plans to practice in the United States. Completion of a CODA accredited specialty program is one of the three educational pathways in order to be eligible for licensing in the U.S. [20]. Perhaps, given the decreased amount of debt, international graduates may have more disposable revenue than domestic graduates, and may consider dental specialization in the U.S. as a financial opportunity to earn a higher income as a specialist.
There were limitations to this study. Not all residents in all U.S. programs could be reached, since their contact information was not accessible through the AAP directory website, which is meant to have residents' contact information. The low response rate (28%) could be partially explained by residents' main focus on completion of their residency program, by the workload needed to successfully fulfill all of a program's requirements, and by a potentially outdated list of e-mail addresses in the AAP directory. However, given the small sample, this study identified interesting and informative factors that describe the choice differences between U.S. and international graduates in selecting periodontal programs. A post-hoc power analysis revealed power ranging from 53.3 to 95.8% for dichotomous variables and 65.8% to 80.5% for continuous variables that were analyzed to detect differences between US and International graduates in this study. Studies with small sample size could potentially reveal important characteristics that could be expanded with larger studies and may be included in systematic reviews [21,22]. Further studies with larger samples are required to increase the power to detect and better understand the differences in influencing factors between U.S. and international graduates' interests in advanced periodontal education.

Conclusion
This study found that a good relationship with predoctoral faculty had a greater influence on American graduates than international graduates when choosing periodontics as a career. Personal finances and program location had a greater negative impact on American graduates than international graduates when selecting an advanced periodontics program of choice. Hence, the increasing cost of dental education in the U.S. as it translates to educational debt incurred by US graduates; could explain the increased enrollment of international students in advanced periodontal education.