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| ORIGINAL ARTICLE |
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| Year : 2016 | Volume
: 8
| Issue : 4 | Page : 199-204 |
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Perception and understanding of dental practitioners in provision of dental treatment to pregnant women in Karachi, Pakistan
Aisha Wali, Talha M Siddiqui, Anum Sarwar, Anum Anjum, Hina Rao
Department of Operative Dentistry, Baqai Dental College, Baqai Medical University, Karachi, Pakistan
| Date of Web Publication | 27-Dec-2016 |
Correspondence Address:
Aisha Wali
Department of Operative Dentistry, Baqai Dental College, Karachi
Pakistan
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/0976-4003.196816
Aim: The aim of the study was to that assess the perceptions and understanding of dental practitioners in the provision of dental treatment to pregnant women. Materials and Methods: The study was a quantitative, cross-sectional type. A sample size of 200 dental practitioners were included in the study between the period of 6 months, i.e. June–December. A cluster sampling technique was employed covering four different dental institutes. A structured questionnaire was designed to assess the perception and understanding of dental practitioners in providing treatment to the pregnant women. Statistical Analysis: Statistical analysis was performed using SPSS version 19. Chi-square test was done to analyze the association of perception of dental practitioners in treating pregnant women in relation to gender. Results: A total of 200 dental practitioners filled the questionnaire out of which 43% (86) were males and 57% (114) were females. Eighty-two percent of the total participants said that it is safe to provide dental treatment during pregnancy, almost 90.4% of the total dentist interviewed was aware of the special position in which to place a pregnant woman on a dental chair. 85.5% of the study population do not prefer taking radiographs of a pregnant woman, 63% of the entire dentist surveyed prefers to use local anesthesia before any dental procedure on a pregnant patient. 96.5% care to educate their pregnant patient about improving dental health care. 59.5% of the dental practitioners said that they would consult the patient's gynecologist as a mandatory requirement before treating the patient. 57% of the dental practitioners answered with gingivitis. 70.5% agreed on scaling. The majority of the dentists prescribed paracetamol 85.5%. Conclusion: Little is known about the perception and utilization of dental practitioners in providing dental treatment to pregnant women in Pakistan. The present survey concluded that dental practitioners lack appropriate knowledge of X-rays and its effects, prescribing appropriate medications, consultation with patients' gynecologist as a mandatory requirement before provision of dental treatment and educating pregnant woman to seek dental care. There is a need to arrange continuous dental education programs for dental practitioners to gain updated knowledge when providing dental treatment to pregnant women. Keywords: Dentists' perception, oral health, pregnant women
How to cite this article:
Wali A, Siddiqui TM, Sarwar A, Anjum A, Rao H. Perception and understanding of dental practitioners in provision of dental treatment to pregnant women in Karachi, Pakistan. Indian J Dent Sci 2016;8:199-204 |
How to cite this URL:
Wali A, Siddiqui TM, Sarwar A, Anjum A, Rao H. Perception and understanding of dental practitioners in provision of dental treatment to pregnant women in Karachi, Pakistan. Indian J Dent Sci [serial online] 2016 [cited 2023 May 28];8:199-204. Available from: http://www.ijds.in/text.asp?2016/8/4/199/196816 |
| Introduction | |  |
Good oral health of a pregnant woman is considered to be of utmost importance for dental practitioners.[1] Dental care during pregnancy is an important aspect for both mother and infant.[2] Guidelines for dental care should be emphasized to improve the oral hygiene of a pregnant woman that will help to manage oral health of the infant.[3] Many believe that poor oral health status during pregnancy is normal. Some believe that dental treatment can harm their fetus and this prevents many women to approach dental practitioners and to neglect their oral health.[4],[5],[6] Dental practitioners also create barriers for pregnant woman to seek dental care. A survey done by Huebner et al.,[7] found that 71% of dental practitioners reported low compensation by insurance plans was a barrier to providing counseling to pregnant patients. Eleven percent reported that they had not enough time for counseling about oral health care to pregnant women during treatment. A study done by gynecologists reported that 77% of dental practitioners declined dental treatment of pregnant women.[8]
Dental practitioners often encounter pregnant patients in a dental setup and are hesitant to provide dental treatment due to fear and uncertainty about the risks posed to both mother and unborn child.[8],[9],[10],[11],[12] This reflects the inadequate knowledge of the dental practitioners in the management of pregnant patients resulting in the under treatment. Researches have shown that majority of the dental practitioners were insufficiently informed and educated in providing treatment to pregnant women.[7],[13],[14],[15],[16],[17]
The results of a survey by Shrout et al.[17] showed that dental practitioners do not provide routine dental treatment during the first trimester and last month of pregnancy. Seventy-eight percent of dental practitioners did not customarily consult the patient's obstetrician before providing routine dental treatment, 50% did not seek a consultation before providing emergency treatment, and 12% did not feel that routine dental treatment should be provided at any time during pregnancy.
However, most of the dental practitioners rate prenatal screening as important but when it comes to practice they believe that radiographs, periodontal surgery, amalgam restorations, and pain medications can be harmful to pregnant women. It was also reported from the survey that gynecologists were more comfortable than the dental practitioners with recommended dental procedures and medications for pregnant women, but were less likely to recommend dental care to their patients.[18] In some occasions, dental practitioners may delay dental care for pregnant women until concerns about possible risks for the fetus and/or mother are eliminated.[19],[20],[21] Pregnant women need to be educated about the importance of oral health care during and after pregnancy.[22] Therefore, gynecologists play a major role in assuring the provision of safe and recommended dental care during pregnancy and encouraging pregnant women to maintain regular visits to dental clinics. In addition, dental practitioners also play an active role in educating pregnant women on the importance of dental care for both mother and infant.[23]
This study is the first of its kind in Pakistan that assessed the perceptions and understanding of dental practitioners in the provision of dental treatment to pregnant women.
| Materials and Methods | | |
Study type
The study was a descriptive, cross-sectional type.
Study population
A sample size of 200 dental practitioners was included in the study between the period of 6 months, i.e. June–December. The sample was calculated by taking this prevalence rate and computed using OpenEpi version 3.01 Version (www.OpenEpi.com) at 95% confidence interval and α = 0.05. The research proposal and survey questionnaire were approved by the ethical committee, Baqai Medical University.
Sampling technique
A cluster sampling technique was employed covering four different dental institutes.
Inclusion criteria
- Registered dental practitioners
- Postgraduates.
Exclusion criteria
Survey instrument
A structured questionnaire was designed to assess the perception and understanding of dental practitioners in providing treatment to the pregnant women. The questions asked were about understanding of dental practitioner in providing treatment to a pregnant woman, deferring treatment of your pregnant patient, special position during treatment, consultation with the gynecologist, most common presenting complaint, procedures that can be performed during pregnancy, preference of taking radiographs, injecting local anesthesia (LA), and educating pregnant women. All the forms were distributed manually and had a same set of questions to maintain a standard assessing criterion.
Statistical analysis
Statistical analysis was performed using SPSS version 19 (IBM). Chi-square test was done to analyze the association of perception of dental practitioners in treating pregnant women in relation to gender.
| Results | | |
A total of 200 dental practitioners filled the questionnaire out of which 43% (86) were male and 57% (114) were females.
[Table 1] shows the understanding and perception of dental surgeons in treating pregnant woman. | Table 1: Understanding and perception of dental practitioners in treating pregnant woman
Click here to view |
Is it safe to provide dental treatment during pregnancy
Around 82% of the total participants said that it is safe to provide dental treatment during pregnancy, of which 40.9% were males and 59.1% were females.
Defer treatment of your pregnant patient
Fifty-two percent of the total participants answered in negative to the question, that if they differ treatment of their pregnant patient, of which 44.2% were males and 55.8% were females.
Any special position in which to place the pregnant woman on a dental chair
Almost 90.4% of the total dentist interviewed was aware of the special position in which to place a pregnant woman on a dental chair.
Preference of taking radiographs during treatment
85.5% of the study population do not prefer taking radiographs of a pregnant woman, of which 58.5% were female and 41.5% were male.
Use of local anesthesia
Sixty-three percent of the entire dentist surveyed prefers to use LA before any dental procedure on a pregnant patient, while 35.5% do not and 1.5% were undecided.
Educate pregnant woman about improving oral hygiene
Almost all of the participants, i.e., 96.5% care to educate their pregnant patient about improving dental health care.
Consultation with the patients' gynecologist as mandatory requirement
59.5% of the participants said that they would consult the patient's gynecologist as a mandatory requirement before treating the patient.
Most common presenting complaint
[Table 2] shows most common presenting complaint encountered by dental practitioner. | Table 2: The most common presenting complaint encountered by dental practitioner
Click here to view |
Fifty-seven percent of the total participants answered with gingivitis and 41% with pain. While sensitivity and halitosis were 1.5% and 0.5%, respectively.
Safest procedure performed during pregnancy
[Table 3] shows knowledge of dental practitioners in the provision of treatment during pregnancy. In response to the safest dental procedure during pregnancy, 70.5% agreed on scaling while root canal treatment (RCT), filling, extraction got 9.5%, 17.5%, and 1.5%, respectively. | Table 3: Knowledge of dental practitioners about the safest dental procedure to be done during pregnancy
Click here to view |
Prescription of medicines during pregnancy
[Table 4] shows knowledge of dental practitioners in prescribing medicines during pregnancy. The medicines surveyed included: Nonsteroidal anti-inflammatory drug (NSAID), paracetamol, penicillin, and tetracycline. Majority of the dentists prescribed paracetamol = 85.5% and NSAID = 4%, penicillin = 10%, and tetracycline = 0.5%, respectively. | Table 4: Knowledge and perception of dental practitioners in prescribing medicines to a pregnant woman
Click here to view |
| Discussion | | |
Routine, preventive, and emergency dental treatment should be provided to pregnant women. Pregnancy-specific guidelines are important for oral health-care education and thus to provide this dental care; knowledgeable dental practitioners should be included as members of the dental health-care team.[7] Various study results showed that providing dental treatment during pregnancy is safe,[24],[25],[26] yet dental practitioners are still hesitant to provide dental treatment during pregnancy. The present study findings showed that 164 (82%) of dental practitioners provide dental treatment during pregnancy. A study in the US found 97% of dentists agreeing on providing dental treatment to pregnant women but only half of them (45%), were “very comfortable” with treating them.[10] Twenty-seven (73%) felt safe to perform dental care in these patients.[27]
Most of the dental practitioners are still unaware of the evidence-based guidelines and lack in training for the perinatal oral health management,[24],[25],[26] the treatment protocols to follow when dealing with the pregnant patient. The present study results showed that 179 (89.5%) of the dental practitioners were aware of the special position for a pregnant woman on dental chair, whereas the statistics on how often this knowledge is practically applicable, 62% of the dental practitioners always prefer to follow this protocol while 36% sometimes follow it depending on the condition/situation of the pregnant women.
The hesitation among dental practitioners, as mentioned earlier, also seems to be about appropriateness of certain dental procedures during pregnancy,[9],[18] with some requiring reassurance from the gynecologists, before proceeding for the treatment. While 15 (40.5%) of the dental practitioners feel the need to consult the patient's obstetrician before any routine dental treatment.[27] The present study results showed that 119 (59.5%) of the dental practitioners preferred to consult gynecologist before starting the treatment. Dental radiographs are considered to be safe for pregnant women, provided protective measures such as high-speed film, a lead apron, and a thyroid collar are used. It has been reported that there is no increase in congenital anomalies or intrauterine growth retardation during pregnancy with the radiation exposure totaling <5–10 cGy.[23],[28] A study result reported that bitewing and panoramic radiographs generates about one-third the radiation exposure associated with a full-mouth series with E-speed film and a rectangular collimated beam.[29] Majority of the Dental practitioners prefer to delay taking a radiograph until after the first trimester; studies showed that dental X-rays may be performed for acute diagnostic purposes on the pregnant women, although it should be delayed until after first trimester. Taking dental radiographs was considered safe throughout pregnancy by six dentists (16.2%). 14 (37.8%) indicated radiography only after the first trimester and 14 professionals (37.8%) contraindicated this procedure during pregnancy.[27]
In spite of these facts, the present study showed that only 27 (13.5%) of the dental practitioners consider taking dental radiographs. A study in India showed 28.5% of dental practitioners willing to take dental radiographs of pregnant patients if necessary.[30] A study done by Da Costa et al.[31] showed that 18.4% agreed that it was unsafe to obtain a radiograph of pregnant women. Dissimilar results were obtained by Huebner et al.[7] which showed that a higher percentage of dental practitioners (56.7%) perform radiographs in pregnant women. Another study results from a European survey showed that 33% of dental practitioners request a radiograph when needed.[30]
The use of LAs with vasoconstrictors is considered as safe throughout pregnancy.[32],[33],[34],[35],[36],[37] However, the anesthetic salt and type and concentration of vasoconstrictors should be observed. The vasoconstrictor felypressin should be avoided due to the potential risk of uterine contraction, as well as bupivacaine salt, due to it long period of action.[33] Methemoglobinemia is a potential side effect of the administration of large doses of prilocaine and articaine.[38] Mepivacaine is not well metabolized by the liver of the fetus. According to most authors, the first choice of anesthetic drug should be lidocaine hydrochloride associated with vasoconstrictor adrenaline at the concentration of 1:100,000.[33],[34],[35],[36],[37] A study done by Zanata et al.[27] showed that only 19% of the dental practitioners made this recommendation. Studies done by Huebner et al.,[7] Lee et al.[9] and Strafford et al.[18] showed 23.5%, 2.1%, and 84% of the dental practitioners administered LA in pregnant woman. The present study results showed a high percentage of dental practitioners who administered LA in pregnant woman.
The majority of the dental practitioners do not prescribe drugs very often to pregnant women.[1] dental practitioners should prescribe medicines with the safety dosages for pregnant and lactating women.[35],[39],[40],[41],[42] Radha and Sood [1] in their study showed that 47% prescribed acetaminophen if needed, compared to 25% for NSAIDs. Sixty-five percent will never give narcotic pain medication to pregnant patients. 44% and 46% will never give site specific antiseptic agent and doxycycline respectively to pregnant women.
A recent study done by Naidu et al.[30] showed that 92.9% of dental practitioners prescribed amoxicillin. The present study result showed that only 10% of dental practitioners prescribed penicillin to a pregnant woman. This is most likely due to the lack of knowledge about their safety. Clinicians should always strive to choose medications that do not cross the placental barriers to affect both the mother and unborn child.[30]
Analgesics are used for over 2 or 3 days to treat a specific disease process. Paracetamol is the safest analgesic for use during pregnancy, but excess dosage can cause liver toxicity. The maximum recommended daily dosage during pregnancy should not exceed more than 4 g/day.[43] Huebner et al.[7] Zanata et al.[27] in their survey showed that 18.7% and 67.6% of dental practitioners prescribed paracetamol to pregnant women. The present survey showed that 85.5% of the dental practitioners prescribed paracetamol to pregnant women. An Indian study similarly revealed that paracetamol was the most commonly prescribed drug among analgesics (91%).[30]
The knowledge and understanding of dental practitioners reflects while providing emergency treatment to pregnant women. More than 84% of the dentists performed extractions, access opening, incision and drainage and placement of temporary restorations on an emergency basis. However, 37% never administered long acting anesthetic in emergency contrary to their higher knowledge.[1] The results of the present study showed that 70.5% of dental practitioners found scaling by far the safest procedure to perform on a pregnant woman, followed by restorations, RCT, and extractions.
The statistics for the most common presenting complaint lean toward gingivitis (57%), followed by pain and sensitivity (41%). This result reinforces the fact that gingivitis is the most common oral disease in pregnancy with a prevalence of 60%–75%.[2]
Educating dental practitioners about the safety of dental treatment during pregnancy can benefit all pregnant women, especially low-income women who are at higher risk of experiencing adverse pregnancy outcomes, including preterm delivery,[44] and untreated dental caries.[45] The present study results showed that 97.5% of dental practitioners educate their pregnant patients about oral health care.
| Conclusion | | |
Oral health care of pregnant women plays an important role, as bad oral hygiene can harm both mother's health and growing fetus. Although dental practitioners provide dental treatment to pregnant woman, still most of them deferred to provide dental treatment to pregnant woman.
Little is known about the perception and utilization of dental practitioners in providing dental treatment to pregnant women in Pakistan. The present study concluded that dental practitioners lack appropriate knowledge of X-rays and its effects, prescribing appropriate medications, consultation with patients gynecologist as a mandatory requirement before provision of dental treatment and educating pregnant woman to seek dental care, performing dental treatment of pregnant women in special position. There is a need to arrange continuous dental education programs for dental practitioners to gain updated knowledge when providing dental treatment to pregnant women.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
| References | | |
| 1. | Radha G, Sood P. Oral care during pregnancy: Dentists knowledge, attitude and behaviour in treating pregnant patients at dental clinics of Bengaluru, India. J Pierre Fauchard Acad 2013;27:135-41.  |
| 2. | Silk H, Douglass AB, Douglass JM, Silk L. Oral health during pregnancy. Am Fam Physician 2008;77:1139-44. |
| 3. | Cardenas LM, Ross DD. Effects of an oral health education program for pregnant women. J Tenn Dent Assoc 2010;90:23-6. |
| 4. | Dinas K, Achyropoulos V, Hatzipantelis E, Mavromatidis G, Zepiridis L, Theodoridis T, et al. Pregnancy and oral health: Utilisation of dental services during pregnancy in Northern Greece. Acta Obstet Gynecol Scand 2007;86:938-44. |
| 5. | Anderson C, Harris MS, Kovarik R, Skelton J. Discovering expectant mothers' beliefs about oral health: An application of the centering pregnancy smiles program. Int Q Community Health Educ 2009-2010;30:115-40. |
| 6. | Keirse MJ, Plutzer K. Women's attitudes to and perceptions of oral health and dental care during pregnancy. J Perinat Med 2010;38:3-8. |
| 7. | Huebner CE, Milgrom P, Conrad D, Lee RS. Providing dental care to pregnant patients: A survey of Oregon general dentists. J Am Dent Assoc 2009;140:211-22. |
| 8. | Morgan MA, Crall J, Goldenberg RL, Schulkin J. Oral health during pregnancy. J Matern Fetal Neonatal Med 2009;22:733-9. |
| 9. | Lee RS, Milgrom P, Huebner CE, Conrad DA. Dentists' perceptions of barriers to providing dental care to pregnant women. Womens Health Issues 2010;20:359-65. |
| 10. | Pina PM, Douglass J. Practices and opinions of Connecticut general dentists regarding dental treatment during pregnancy. Gen Dent 2011;59:e25-31. |
| 11. | George A, Shamim S, Johnson M, Dahlen H, Ajwani S, Bhole S, et al. How do dental and prenatal care practitioners perceive dental care during pregnancy? Current evidence and implications. Birth 2012;39:238-47. |
| 12. | Alves RT, Ribeiro RA, Costa LR, Leles CR, Freire Mdo C, Paiva SM. Oral care during pregnancy: Attitudes of Brazilian public health professionals. Int J Environ Res Public Health 2012;9:3454-64. |
| 13. | Pertl C, Heinemann A, Pertl B, Lorenzoni M, Pieber D, Eskici A, et al. The pregnant patient in dental care. Survey results and therapeutic guidelines. Schweiz Monatsschr Zahnmed 2000;110:37-46. |
| 14. | Pistorius J, Kraft J, Willershausen B. Dental treatment concepts for pregnant patients – Results of a survey. Eur J Med Res 2003;8:241-6. |
| 15. | Al-Sadhan R, Al-Manee A. Dentists' opinion toward treatment of pregnant patients. Saudi Dent J 2008;20:24-30. |
| 16. | Williams LC, Stevens S, Marti A, Koelbl J, Wearden S. 3180 dentist's attitude on treatment of pregnant patients in West Virginia. IADR 2005;5:16-20. |
| 17. | Shrout MK, Potter BJ, Comer RW, Powell BJ. Treatment of the pregnant dental patient: A survey of general dental practitioners. Gen Dent 1994;42:164-7. |
| 18. | Strafford KE, Shellhaas C, Hade EM. Provider and patient perceptions about dental care during pregnancy. J Matern Fetal Neonatal Med 2008;21:63-71. |
| 19. | Gaffield ML, Gilbert BJ, Malvitz DM, Romaguera R. Oral health during pregnancy: An analysis of information collected by the pregnancy risk assessment monitoring system. J Am Dent Assoc 2001;132:1009-16. |
| 20. | Lydon-Rochelle MT, Krakowiak P, Hujoel PP, Peters RM. Dental care use and self-reported dental problems in relation to pregnancy. Am J Public Health 2004;94:765-71. |
| 21. | Timothé P, Eke PI, Presson SM, Malvitz DM. Dental care use among pregnant women in the United States reported in 1999 and 2002. Prev Chronic Dis 2005;2:A10. |
| 22. | Al Habashneh R, Guthmiller JM, Levy S, Johnson GK, Squier C, Dawson DV, et al. Factors related to utilization of dental services during pregnancy. J Clin Periodontol 2005;32:815-21. |
| 23. | Katz J, Orchard AB, Ortega J, Lamont RJ, Bimstein E. Oral health and preterm delivery education: A new role for the pediatric dentist. Pediatr Dent 2006;28:494-8. |
| 24. | |
| 25. | |
| 26. | California Dental Association Foundation; American College of Obstetricians and Gynecologists, District IX. Oral health during pregnancy and early childhood: Evidence-based guidelines for health professionals. J Calif Dent Assoc 2010;38:391-403, 405-40. |
| 27. | Zanata RL, Fernandes KB, Navarro PS. Prenatal dental care: Evaluation of professional knowledge of obstetricians and dentists in the cities of Londrina/PR and Bauru/SP, Brazil, 2004. J Appl Oral Sci 2008;16:194-200. |
| 28. | National Council on Radiation Protection and Measurements. Recommendations on Limits for Exposure to Ionizing Radiation. NCRP Report No. 91. Bethesda, MD: NCRP; 1987. |
| 29. | Freeman JP, Brand JW. Radiation doses of commonly used dental radiographic surveys. Oral Surg Oral Med Oral Pathol 1994;77:285-9. |
| 30. | Naidu GM, Ram KC, Raj Kumar CK. Is dental treatment safe in pregnancy? A dentists' opinion survey in South India. J Orofac Res 2013;3:233-9. |
| 31. | Da Costa EP, Lee JY, Rozier RG, Zeldin L. Dental care for pregnant women: An assessment of North Carolina general dentists. J Am Dent Assoc 2010;141:986-94. |
| 32. | Andrade ED. Terapêutica Medicamentosa em Odontologia. São Paulo: Artes Médicas; 2002. |
| 33. | Haas DA. An update on local anesthetics in dentistry. J Can Dent Assoc 2002;68:546-51. |
| 34. | Hilgers KK, Douglass J, Mathieu GP. Adolescent pregnancy: A review of dental treatment guidelines. Pediatr Dent 2003;25:459-67. |
| 35. | Moore PA. Selecting drugs for the pregnant dental patient. J Am Dent Assoc 1998;129:1281-6. |
| 36. | Tortamano N, Armonia PL. Local anesthetics. In: Tortamano N, Armonia PL. Dental therapeutic guide. 14. ed. São Paulo: Santos; 2001. Chap. 4. p. 30-41. |
| 37. | Turner MD, Singh F, Glickman RS. Dental management of the gravid patient. N Y State Dent J 2006;72:22-7. |
| 38. | Malamed SF. Handbook of local anesthesia. 4 th ed. St. Louis: Mosby; 1997:193-219. |
| 39. | Balligan FJ, Hale TM. Analgesic and antibiotic administration during pregnancy. Gen Dent 1993;41:220-5. |
| 40. | Folb PI, Graham Dukes MN. Drug Safety in Pregnancy. Amsterdam: Elsevier Science Publishers BV; 1990. p. 15-8. |
| 41. | Briggs GG, Freeman RK, Yaffe SJ. Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk. 3 rd ed. Baltimore: Williams and Wilkins; 1990. |
| 42. | United States Food and Drug Administration. Labeling and prescription drug advertising: Content and format for labeling for human prescription drugs. Fed Regist 1979;44:37434-67. |
| 43. | Meadows M. Pregnancy and the drug dilemma. FDA Consum 2001; 35:16-20. |
| 44. | ACOG Practice Bulletin. Assessment of risk factors for preterm birth. Clinical management guidelines for obstetrician-gynecologists. Obstet Gynecol 2001;98:709-16. |
| 45. | Centers for Disease Control and Prevention. QuickStats: Percentage of persons with untreated dental caries, by age group and poverty status-national health and Nutrition Examination Survey (NHANES), United States, 2001-2004. MMWR Morb Mortal Wkly Rep 2007;56:889. |
[Table 1], [Table 2], [Table 3], [Table 4]
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