Musculoskeletal disorders and emergent themes of psychosocial factors and their impact on health in dentistry

Abstract

BACKGROUND:

Dentistry is a profession where musculoskeletal disorders are prevalent. Physical demands and static awkward postures increase the risks of dentists developing musculoskeletal disorders. In addition, researchers have identified psychosocial factors that can influence the health of workers.

OBJECTIVE:

The aim of this research is to present self-reported pain regions and to assess psychosocial work factors as they relate to dentistry.

METHOD:

Fourteen dentists participated in the study. Data was collected via a questionnaire administered prior to the start of and during the study. Descriptive statistics were used for data analysis.

RESULTS:

All dentists self-reported to be in good to excellent health and only 50% sought medical treatment for work-related discomfort and pain. Thirteen of 14 reported being at least occasionally mentally and physically exhausted after work. A musculoskeletal disorder–work hour relationship model was created. Feedback given was linked to four psychosocial factors –job demand, job control, social interactions, and job future and career issues.

CONCLUSIONS:

The dental profession is considered a highly cognitive profession where much attention has been placed on the physical demands due to awkward postures. While physical demands are validated, additional research will further validate the link between psychosocial and mental and physical demands.

Keywords

Stress factors dentists cumulative trauma disorders health ergonomics

1 Introduction

In 2015, there were almost 196,000 licensed practicing dentists in the United States, of whom 29% are female [1]. Research in the field of dentistry has revealed high prevalence of musculoskeletal disorders (MSDs) among those in the dental profession [2 –9]. These MSDs have been linked to a wide range of contributory factors related to the work environment, tasks performed, task descriptives, and personal influencers. Duration of tasks, frequency, and grip type are a few of the factors under the category of task descriptives, while gender, height, hobbies and ergonomic awareness are personal factors. Some of these influencers are shown in Fig. 1. Continued exposure to risks has led researchers to call for appropriate occupational health and safety measures to be adopted and adhered to by dental staff [4].

Fig. 1

Factors potentially contributing to MSDs in dentistry [6].

In a British study of 189 dentists who retired prematurely with ill health, but non-life- threatening diseases, 55% were found to have had MSDs; the primary cause of early retirement. The second highest cause of ill health retirement was mental and behavioral disorders (28%), followed by disease of the nervous system/sense organs [10]. In a study of 1670 Lithuanian dentists, fatigue, headache, hand problems, chest pain and especially musculoskeletal complaints had a highly negative impact on general health. A total of 94.7% complained of being physically burned out (40.5% chronically), with 91% of the dentists reporting suffering from back pain (57.1% chronically) and 88.7% (23.4% chronically) reporting suffering with headaches. The majority of the responders to the questionnaire experienced some mental impairments in the previous year, which co-occurred with the reported physical ailments. Nervousness (89.2%) was the most prevalent impairment with 83.6% experiencing psychical burnout [11, 12]. In a random sample of 254 Illinois general dentists, of the 202 respondents to a survey, though 50–60% were satisfied with the profession, 83% perceived dentistry to be “very stressful” and 7.4% had reached significant levels of burnout [13].

In addition to physical risk factors and stressors, researchers have identified psychosocial factors that may influence the health of these professionals. Physical and psychosocial work factors can be related to the same outcomes, one of which is the work-related musculoskeletal disorders (WMSDs). Psychosocial work factors have been deemed crucial components of physical ergonomics. To fully prevent or reduce WMSDs, both physical and psychosocial work factors need to be considered [14]. The idea of considering physical and psychosocial work factors is backed by one of the earlier models of job strain which postulated that psychological strain did not result from a single aspect of the work environment, but from the joint effects of the demands of a work situation and decision making freedom [15]. Eight categories of psychosocial work factors – job demand, job content, job control, social interactions, role factors, job future and career issues, technology, and organizational and management issues – and specific contributors within each category are shown in Table 1.

Table 1

Selected Psychosocial Work Factors and their facets [14]

1.	Job demands	Quantitative workload
		Variance in workload
		Work pressure
		Cognitive demands
2.	Job content	Repetitiveness
		Challenge
		Utilization and development of skills
3.	Job control	Task/instrumental control
		Decision/organizational control
		Control over physical environment
		Resources control
		Control over work pace: machine-pacing
4.	Social interactions	Social support from supervisor and colleagues
		Supervisor complaint, praise, monitoring
		Dealing with (difficult) clients/customers
5.	Role factors	Role Ambiguity
		Role conflict
6.	Job future and career issues	Job future ambiguity
		Fear of job loss
7.	Technology issues	Computer-related problems
		Electronic performance monitoring
8.	Organizational and management issues	Participation
		Management style

Based on the role and position of the dentists, four of the eight psychosocial work factors – job content, role factors, technology issue, and organizational and management issues – are omitted from this analysis. For instance: Job content, which considers repetitiveness and utilization, is not deliberated. By the nature of the job, procedures performed can be repeated multiple times during a normal work day. However, a dentist can exercise some control over the types of procedures scheduled on a particular day. Utilization and development of skills are less relevant to the dental profession, as dentistry is a challenging, highly skilled profession with a specialized skillset and numerous opportunities for professional development. The role of the dentists, especially those self-employed, is not ambiguous nor conflicting. Therefore, role factor was not considered, as all participants in this study were either single owner or partners. Their performance was not subjected to electronic monitoring or scrutiny of any other decision makers, only their own self-assessment; thereby eliminating the technology issues psychosocial factor. Finally, organizational and management issues are not considered. For self-employed dentists, the practitioner is a full participant. His or her management style is self-determined. Whether employee participation and management style are favorable to the employees is beyond the scope of this research. The remaining four psychosocial factors – job demands, job control, social interactions, and job future and career issues – are deemed relevant and are explored. The aim of this research paper is to assess the psychosocial work factors as they relate to dentistry.

2 Method

2.1 Participants

The data for this study was gathered from 14 dentists, five females and nine males. Twelve dental professionals were recruited from practitioners in Greensboro, North Carolina, and surrounding cities of the United States (US). Two were recruited from Albany, Georgia. The participants had a mean height of 171.73 (SD = 11.5) cm, a mean weight of 76.47 (SD = 10.23) kg, and 19.43 (SD = 12.36) years of practice (with a range of 2 to 43 years). Weight was not collected for two participants. All were either in private practice; either single proprietor or partnership. Two were orthodontists, two were pediatric dentists and all others were general practitioners. While psychosocial work factors can apply to dental assistants, dental hygienists, technicians, and others in a dental office, dentists are the only targeted population for this study. It is believed that the role and status of the dentists in the dental office hierarchy differs enough that dentists are analyzed as a single entity.

2.2 Data collection and processing

Data were collected as part of a larger research project to evaluate muscle activity using electromyography and upper body motion during specific dental procedures. A questionnaire and supplemental survey were created by the research investigator. The discomfort survey by the Workplace Safety & Prevention Services (WSPS) of Ontario, Canada was modified by altering or adding questions specific to dentistry (“Discomfort Survey_final,” n.d.; Pope-Ford, 2013). To assess ergonomic pain, risks, or posture concerns, the modified WSPS discomfort survey was given to each observed or laboratory participant. Participants could identify up to 13 areas of pain or discomfort with use of a body map as part of the discomfort survey. Additional questions sought information regarding medical treatment for discomfort experienced and missed days of work due to discomfort and pain in the identified areas. The supplemental survey captured additional anthropometric data and workplace specifics such as operating space, distance to instruments and layout of work space. Participants were queried on how often mental and physical exhaustion were experienced after work. One of four responses could be selected – never, occasionally, often or always. Questions on whether or not medical treatment was sought and the type of medical treatment were also asked.

Discomfort and supplemental surveys were either emailed or faxed upon request. Prior to the start of the experiment, all participants were informed of the requirements of the experiment and written consent was obtained. Additional data was obtained through voluntary comments from participant interviews during the observational (dentists 1 and 2) and laboratory (dentists 3 – 14) studies and duly noted, in a notebook, by the investigator when given by participants. Data were analyzed using descriptive statistics and calculated in Microsoft Excel. Chi-square Goodness of Fit analysis was performed to determine if there was no significant difference between years of practice and the number of pain areas (i.e. years of practice are not associated with the number of pain areas; null hypothesis). This research compiled with the tenets of the Declaration of Helsinki was approved by the Institutional Review Board (IRB) at Bradley University.

3 Results

Six of the twelve participants, in the laboratory study, reported being in good health (defined as minimal health issues, with some or no medication), while the other six reported being in excellent health (no health problems or medication). All indicated they exercised at least once a week, with eight indicating they exercised three or more times/week. Health and exercise activity data was not available for two of the 14 dentists. The orthodontists each indicated they saw 50 patients per day, while the other practitioners saw a mean of 14 (SD = 7) patients per day. The minimum and maximum number of patients seen per day was four and 28, respectively, excluding orthodontists. Six of the twelve pediatric and general dentists saw 15 or more patients per day.

With the exception of one participant, each person reported experiencing, at some time in the last twelve months, some musculoskeletal pain thought to be related to work. Without exception, all participants identified areas of discomfort in at least one body region. The mean number of identified areas of body pain was approximately four, with a maximum number of areas identified as nine. See Table 2.

Table 2
Years of Practice vs. Pain Areas

Participant # # Yrs. in practice Areas of pain Mental exhaustion after work Physical exhaustion after work

1 15 3 Occasionally Often

2 33 4 Occasionally Occasionally

3 17 1 Occasionally Occasionally

4 12 3 Occasionally Occasionally

5 29 5 Occasionally Occasionally

6 14 8 Occasionally Occasionally

8 38 4 Occasionally Occasionally

9 43 9 Occasionally Occasionally

10 6 5 Often Occasionally

11 16 2 Often Occasionally

12 15 1 Never Never

13 25 3 Occasionally Occasionally

14 7 3 Occasionally Often

Average 19.43 3.93

Std Dev. 12.36 2.30

Min 2 1

Max 43 9

Median 15.50 3.50

Participant # #	Yrs. in practice	Areas of pain	Mental exhaustion after work	Physical exhaustion after work
1	15	3	Occasionally	Often
2	33	4	Occasionally	Occasionally
3	17	1	Occasionally	Occasionally
4	12	3	Occasionally	Occasionally
5	29	5	Occasionally	Occasionally
6	14	8	Occasionally	Occasionally
8	38	4	Occasionally	Occasionally
9	43	9	Occasionally	Occasionally
10	6	5	Often	Occasionally
11	16	2	Often	Occasionally
12	15	1	Never	Never
13	25	3	Occasionally	Occasionally
14	7	3	Occasionally	Often
Average	19.43	3.93
Std Dev.	12.36	2.30
Min	2	1
Max	43	9
Median	15.50	3.50

When asked to select how often they felt mentally exhausted after work, one practitioner stated never, 11 reported occasionally, and two reported often. When asked, How often are you physically exhausted after work?, given the same four choices, one selected never, 11 occasionally, and two often (Table 2). All reported zero time was lost from work due to the reported pain. In addition, no one reported restricted duty because of pain. Chi-square Goodness of Fit analysis showed years of practice was not associated with the number of areas of pain. Figure 2 shows the body areas and the prevalence of reported discomfort and/or pain in each of the areas. Neck (93%), lower back (71.4%) and shoulders (64.3%) were the most prevalent symptom areas.

Fig. 2

Incidence of musculoskeletal symptoms within the past 12 months (n = 14).

4 Discussion

Analysis of the reported areas of discomfort and pain for the 14 dentists identified multiple MSDs. The prevalence of neck, back, and shoulder symptoms were in agreement with other research studies [2–5 , 12]. Further analysis of the identified symptoms, the practitioners’ occupation, and responses to the collected qualitative data – surveys and comments – revealed the emergence of psychosocial themes. Based on the responses given by the study participants and a general review of the profession, at least four areas of psychosocial factors were readily identified [14]. These four areas, job demand, job future and career issues, job control, and social interactions and physical symptoms are discussed.

4.1 Job demands – physical and mental

Dentistry is recognized as a physically and mentally demanding occupation, by the participants of this study and by other researchers [16]. Despite the prevalence of pain in certain body regions, only four of 14 (29%) of the practitioners sought medical treatment for pain areas. The treatments described for the four dentists were massage or deep tissue massage therapy, with one also seeking chiropractic care. One of the four dentists who sought care, also took over-the-counter (OTD) pain relievers, received a cortisone shot and received acupuncture. The practitioners who sought medical care included the dentist who reported never experiencing mental or physical exhaustion.

For areas of pain not treated or for those who reported not seeking medical treatment, it was stated that chiropractic care or massages were considered. OTD relief had also been administered at some point in time. (The taking of OTD medication, shows a difference in how medical treatment is defined.) Other responses were a clear indication that discomfort and pain are seen as an acceptable hazard. Acceptance of the fatigue, discomfort and pain as part of the job was evident by the statements of those who had not sought medical treatment: 1) “pain is an occupational reality,” 2) “treatment is not necessary, as symptoms are not significant for long periods of time,” and 3) “pain did not bother me enough to seek help.” Three people gave the last reason as a response. The percentage of practitioners who sought medical treatment (29%) was less than the 50% findings of Leggat et al. (Leggat, Kedjarune, & Smith, 2007).

For this study, the number of dentists who reported to be in good to excellent health was 100%. Although all dentists could attribute the identified symptoms to their work environment, each consistently worked through the discomfort, as no days of work were lost nor was any work done on a restricted schedule. A search of the evidence literature did not reveal specific discussion of the annual number of sick days recorded by dentists in the US. Working through pain and losing no days of work for the 14 US dentists, differs from the findings of researchers of non-US dentists. Job demand was recognized as a factor in physical exertion in Greek dentists. For chronic complaints and absenteeism, self-reported aspects of physical load were reported by Alexopoulos et al to be significant for hand/wrist complaints (where strenuous shoulder/hand movement had an OR of 3.27 for chronicity and 5.05 for absenteeism) [17].

Physical stress was recognizable and documented based on the dentists’ responses. As well, cognitive demand, one of the facets of job demand was identified [14]. With the exception of one dentist, all respondents reported feelings of mental exhaustion occasionally or often after work. None reported the burnout of previous studies [13]. However, the reported mental exhaustion confirms the cognitive demands of the dental profession, in addition to physical exhaustion. Additional research with questions aimed at discovering the specifics of cognitive job demand could possibly show a link between physical and cognitive exhaustion.

4.2 Job future and career issues

During times of an economic down turn and a slow recovery of the economy, dentists have faced many challenges. This job strain can lead to stress and sleep disturbance [18]. Dentists of this study were no exception, and evidence suggests the nature of the work of a dentist implies that problems related to the working environment and health are likely to be encountered [19].

Delineating on these previous findings, additional psychosocial facets emerged during data collection. The association of job future ambiguity and concern for job sustainment were apparent per comments by some practitioners. Three dentists (21%) stated that the demand of high overhead brought an increasing concern for operating a private practice and the continuation of long work hours. Based on this input a model of musculoskeletal disorder – work hour relationship was developed. The model shows a cycle of the need to build and sustain a successful practice leading to long work hours coupled with the occupational requirement of holding static awkward postures which, in turn, increase the risks of developing MSDs and thus working through the symptoms as the cycle continues; demonstrated in Fig. 3. The job sustainment stressor is exacerbated by supply costs, the need to update equipment or technology, and staff support. Financial success of the practice sustains not only the practitioner and his or her family, but the staff and their families; thus, the need for these professionals to work longer even with discomfort or pain. As self-reported many work through the symptoms. This is consistent with other research [4, 16]. Further research can validate the musculoskeletal disorder – work hour relationship model.

Fig. 3

Musculoskeletal disorder – work hour relationship.

4.3 Job control

Job control has been shown to be one of the strongest psychosocial predictors of sickness absence, morbidity and mortality [20]. Dentists in this study reported no absences from work for the last 12 months. When it comes to job control, dentists demonstrated they are empowered and do exercise control when determining the source of earned income and the number of hours spent treating patients per week; not always adhering to the guidelines of its organizations. Perhaps, it is the autonomy that lessens stress in a physically and mentally demanding occupation and the self-reported good and excellent health for the 12 US dentists. For instance, the mission of the American Academy of Pediatric Dentistry (AAPD) is to “advocate policies, guidelines, and programs that promote optimal oral health and oral health care for infants and children through adolescence, including those with special health care needs [21].” The AAPD has focused its efforts on addressing the disparities between children who are at risk of having high rates of dental caries and the millions of US children who enjoy access to quality oral health care. (Eighty percent of dental caries, the most common chronic disease of children in the US, are found in 20 to 25% of children; large portions who live in poverty or low-income households and lack access to on-going quality dental care [21]). Despite the AAPD advocacy, the pressures to build and sustain a practice that supports not only themselves, their families, and their employees, practitioners exercise choice in acceptance of patients and the type of insurance accepted. Health care professionals often elect not to participate as providers in Medicaid or State Children’s Health Insurance Programs (CHIP) due to low reimbursement rates, administrative burdens, and the frequency of failed appointments by patients whose treatment is publicly funded [22 –27]. Per 1,679 private practicing dentists, responding to a nationwide survey sent to 8,769 dentists, 5.4% of patients were covered by public assistance programs. Of all practicing dentists, general and specialists, pediatric dentists reported the highest number of patients with public assistance (24.5% in 2011; up from 17.5% in 1999), followed by oral and maxillofacial surgeons (8.9% in 2011). Endodontists and periodontists report the lowest number of patients with public assistance, 0.9% (American Dental Association, 2011).

Another driver for the job control is the reimbursement rate. The mean number of days for reimbursement from government programs is 38.8 days, while the reimbursement from dental plans and commercial insurance carriers ranges from 19.4–23.6 [28, 29]. Of the participants in this study, four of 14 accepted patients with public assistance; both pediatric dentists and two general dentists. The 1999 Survey of Dental Fees also noted that the range of hours spent treating patients ranged from 27.2 (prosthodontics) to 34.7 (endodontics) hours. The question of how many hours were spent treating patients was not asked of the participants of this study [29]. The high level of job control – patient selection, preferred insurance type and reimbursement rate, and hours worked – by dental practitioners could offer a partial explanation of why the participants in this study report no missed days of work due to sickness and good and excellent health. Such findings would be supported by prior research [20].

4.4 Social interactions

Social interaction such as social support and patient difficulty are components of psychosocial factors in the work place. Support can be divided into informational, instrumental, emotional, and appraisal support. In this paper, only the emotional level is examined. Persons who feel a lack of support from co-workers often feel less valued and may have lower levels of productivity than those who feel they have support [15]. Dentistry can be a lonely profession even though the dentist is surrounded by people [30]. Dentists working in solo practice are more liable to report high levels of emotional exhaustion and low levels of personal accomplishment [31]. Whereas, previous researchers focused on emotional exhaustion, this study asked about mental exhaustion: all but one dentist reported feeling mentally and physically exhausted either occasionally (79%) or often (14%) after work. The surveys administered for this research did not ask nor did anyone report feelings of low levels of personal accomplishment. Additional research is needed to determine if the reported mental exhaustion reported can be redefined or modified to distinguish mental from emotional exhaustion.

Dentists not only described musculoskeletal pain, but also stress from a lack of a support while at work. One participant commented on not having anyone with which to discuss treatment plans, especially when in a solo practice. Another support concern was the confidentiality constraint that confines the dental professional from venting about stressful situations at work, leaving the dentist to cope with the emotions all alone. Poor social support has also been associated with incidence of reported back trouble [32]; a psychosocial link to the additional inquiries are needed to confirm the social support and back trouble link reported by Bongers et al.

One other noteworthy interaction is the change in socialization and the acceptance of authority that, at times, has led to challenges in doctor-patient relationships. When treating the pediatric patients, there may be parental and patient behavioral challenges. Communication problems between dentists, patients or the caregiver, may lead to frustration on both sides. During recent years, a change has been described, from a mainly paternalistic role of the health professional to increasing emphasis on the right of patients to choose for themselves and to have a more active role in the relationship [33]. The shift in roles has allowed the patient or parent to make choices, in the opinion of the dentist, that may not have the best outcome for the patient. One dentist confirmed the doctor-patient challenge and added that many times the dental professional is left with the decision of whether or not to treat the patient. Patient independence creates a climate contrary to the dentist’s preference for patients who are regarded as cooperative, content with the service provided, and follows instructions [34]. This creates a dilemma and a degree of discouragement.

5 Conclusion

Dentistry is known for the high cognitive demand and awkward postures endured, due to the intense focus required to deliver quality patient care. The preliminary findings of this research reveal a possible link between to the prevalence of MSDs reported by practitioners of dentistry and psychosocial factors. Heretofore, most researchers have attributed the physical discomfort and pain primarily to awkward postures. Based on the findings of this research, additional focus should be placed on psychosocial factors, for a cause and effect relationship that is greater than realized, previously. It is recognized that a sample size of 14 dentists, a limitation of this research, should be increased to recognize the results as valid. Nevertheless, the small sample size of 14 dentists pointed to additional stressors that are present in the workplace and are likely contributors to the high prevalence of MSDs. Further studies should examine these psychosocial factors and their facets for US dentists. Of particular interest are the findings of European studies sickness absence as an issue of concern, yet none of the dentists in this study reported sickness absence for the previous year. Findings with a larger sample size would further validate the findings of this small study. A larger population will allow for comparisons to be made between practitioners in the US and the previous European studies. Results would be generalizable and could validate the work of previous researchers who found an association between sickness absence and back pain and the psychosocial factor of job control and sick leave.

Conflict of interest

None to report.

Footnotes

Acknowledgments

In addition to the participants to of the study, the authors would like to thank North Carolina A&T Title III office for partial funding of the research, Dr. Jeannette Pope-Ozimba and the North Carolina Oral Health Society for use of equipment, and the Bradley University Caterpillar Fellowship Award.

References

Munson

, Vujicic

. Number of practicing dentists per capita in the United States will grow steadily. Health Policy Institute Research Brief. American Dental Association, 2016.

Akesson

, Hansson

, Balogh

, Moritz

, Skerfving

. Quantifying work load in neck, shoulders and wrists in female dentists. Int Arch Occup Environ Health. 1997;69(6):461–74.

Akesson

, Johnsson

, Rylander

, Moritz

, Skerfving

. Musculoskeletal disorders among female dental personnel – clinical examination and a 5-year follow-up study of symptoms. Int Arch Occup Environ Health. 1999;72(6):395–403.

Leggat

, Kedjarune

, Smith

. Occupational health problems in modern dentistry: A review. Indust Health. 2007;45(5):611–621.

Morse

, Bruneau

, Dussetschleger

. Musculoskeletal disorders of the neck and shoulder in the dental professions. Work. 2010;35(4):419–429.

Pope-Ford

. Assessment of neck and shoulder muscle coactivations and the effect on the musculoskeletal system [Ph.D.]. Ann Arbor: North Carolina Agricultural and Technical State University; 2013.

Finsen

, Christensen

. A biomechanical study of occupational loads in the shoulder and elbow in dentistry. Clin Biomech. 1998;13(4-5):272–79.

Finsen

, Christensen

, Bakke

. Musculoskeletal disorders among dentists and variation in dental work. Appl Ergon. 1998;29(2):119–25.

Guay

. Commentary: Ergonomically related disorders in dental practice. J Am Dent Assoc. 1998;129(2):184–186.

10.

Brown

, Burke

FJT

, Macdonald

, et al. Dental practitioners and ill health retirement: Causes, outcomes and re-employment. Br Dent J. 2010;209(5):E7.

11.

Puriene

, Aleksejuniene

, Petrauskiene

, Balciuniene

, Janulyte

. Self-perceived mental health and job satisfaction among Lithuanian dentists. Indust Health. 2008;46(3):247–52.

12.

Puriene

, Aleksejuniene

, Petrauskiene

, Balciuniene

, Janulyte

. Self-reported occupational health issues among Lithuanian dentists. Indust Health. 2008;46(4):369–74.

13.

Baran

. Myers Briggs Type Indicator, burnout, and satisfaction in Illinois dentists. Gen Dent. 2005;53(3):228–34, quiz 235.

14.

Carayon

, Lim

S-Y

. Psychosocial work factors. In: Marras WS, Karwowski W, editors. The occupational ergonomics handbook: Fundamentals and assessment tools for occupational ergonomics (2nd ed). Boca Raton, FL: CRC Press; 2006:26-21-26-29.

15.

Karasek

. Job demands, job decision latitude, and mental strain – implications for job redesign. Admin Sci Q. 1979;24(2):285–308.

16.

Puriene

, Janulyte

, Musteikyte

, Bendinskaite

. General health of dentists. Literature review. Stomatologija. 2007;9(1):10–20.

17.

Alexopoulos

, Stathi

I-C

, Charizani

. Prevalence of musculoskeletal disorders in dentists. BMC Musculoskelet Disord. 2004;5(1):1.

18.

Takaki

, Taniguchi

, Fukuoka

, et al. Workplace bullying could play important roles in the relationships between job strain and symptoms of depression and sleep disturbance. J Occup Health. 2010;52(6):367–74.

19.

Berthelsen

, Hjalmers

, Soderfeldt

. Perceived social support in relation to work among Danish general dental practitioners in private practices. Eur J Oral Sci. 2008;116(2):157–163.

20.

Vahtera

, Kivimäki

, Pentti

, Theorell

. Effect of change in the psychosocial work environment on sickness absence: A seven year follow up of initially healthy employees. J Epidemiol Community Health. 2000;54(7):484–93.

21.

Council on Clinical Affairs. Policy on workforce issues and delivery of oral health care sercices in a dental home. Pediatr Dent. 2015;37(6):26–29.

22.

Decker

. MEdicaid payment levels to dentists and access to dental care among children and adolescents. JAMA. 2011;306(2):187–93.

23.

Damiano

, Brown

, Johnson

, Scheetz

. Factors affecting dentist participation in a state Medicaid program. J Dent Educ. 1990;54(11):638–43.

24.

Hughes

, Damiano

, Kanellis

, Kuthy

, Slayton

. Dentists’ participation and children’s use of services in the Indiana dental Medicaid program and SCHIP: Assessing the impact of increased fees and administrative changes. J Am Dent Assoc. 2005;136(4):517–23.

25.

Waldman

, Perlman

. Why dentists shun Medicaid: Impact on children, especially children with special needs. J Dent Child. 2003;70:5–9.

26.

Morris

, Freed

, Nguyen

, Duperon

, Freed

, Dickmeyer

. Pediatric dentists’ participation in the California medicaid program. Pediatr Dent. 2004;26(1):79–86.

27.

Waldman

, Perlman

. Counting the number of children with disabilities. Pediatr Dent. 2004;26(1):49–52.

28.

American Dental Association. 2011 survey of dental fees Chicago, Illinois: American Dental Association, 2011 978-1-60122-146-9.

29.

American Dental Association. 1999 survey of dental fees. Survey. Chicago, Illinois American Dental Association, 1999 July 2000.

30.

Hjalmers

, Soderfeldt

, Axtelius

, Kronstrom

. Network participation for unpromoted female dentists in relation to psychosocial support. Acta Odontol Scand. 2004;62(3):158–62.

31.

Croucher

, Osborne

, Marcenes

, Sheiham

. Burnout and issues of the work environment reported by general dental practitioners in the United Kingdom. Community Dent Health. 1998;15(1):40–43.

32.

Bongers

, de Winter

, Kompier

, Hildebrandt

. Psychosocial factors at work and musculoskeletal disease. Scand J Work Environ Health. 1993;19(5):297–312.

33.

Bruers

JJM

, Felling

AJA

, Truin

, van’t Hof

, van Rossum

. Patient orientation and professional orientation of Dutch dentists. Community Dent Oral Epidemiol. 2004;32(2):115–24.

34.

Brennan

, Spencer

. Dentist preferences for patients: Dimensions and associations with provider, practice, and service characteristics. Int J Behav Med. 2006;13(1):69–78.