K. Aoygi-Nk, A. Kod, T. Kwkmi, H. Kribe Deprtment of Peditric Dentistry, School of Life Dentistry, Nippon Dentl University, Tokyo, Jpn e-mil: h-kribe@tky.ndu.c.jp Fctors ffecting psychologicl stress in children who cooperte with dentl tretment: pilot study bstrct Aim Few studies hve exmined psychologicl stress nd personl nxiety in children exhibiting coopertive behviour during dentl tretment. We ssessed psychologicl stress nd personl nxiety during dentl tretment in coopertive children, nd investigted the influence of vrious fctors. Mterils nd methods We mesured pre- nd post-tretment slivry lph mylse (saa) levels of 28 children ged 8 13 yers nd their prents. Children completed the Stte-Trit Anxiety Inventory for Children (STAIC); their prents completed the STAI. The included children whose saa levels incresed >10%, wheres the included children whose saa levels decresed >10%. We used regression models to clculte the power of vribles to predict children s psychologicl stress. Results The men nxiety trit score in the ws significntly higher thn in the (t-test, P = 0.021). For children with higher STAIC Trit scores, the OR for incresing saa ws 1.16 (95% CI [1.02 1.31]). Prentl or tretment fctors did not significntly contribute to incrementl saa levels in children. Conclusion Well-behved children with high nxiety trits my experience high stress levels during dentl tretment; however, prentl nd dentl tretment fctors my not ffect psychologicl stress in these children. Keywords Children; Dentl nxiety; Fer; Prents; Slivry lph mylses. Introduction Most ptients consider dentl tretment to be n unplesnt experience. Peditric ptients, in prticulr, often exhibit uncoopertive behviour during dentl procedures. The prevlence of dentl fer mong children is 5 20%, with men prevlence of 11% [Klingberg nd Broberg, 2007]. Although mny cse-controlled studies hve ssessed dentl fer in uncoopertive peditric ptients [Arnrup et l., 2007; Gustfsson et l., 2010], few studies hve focused on psychologicl stress nd personl nxiety in children who exhibit coopertive behviour during dentl tretment. Eli et l. [2008] suggested tht mny dentists re not sufficiently wre of the stress tht dentl procedures cn cuse, or its possible effect on their ptients. Moreover, few studies hve considered the psychologicl stress nd personl nxiety experienced by prents during their children s dentl tretment nd the possible influence on their children s stress nd nxiety. Children s responses to dentl tretment re typiclly mesured bsed on self-reported questionnires, externl behviourl responses, nd internl physiologicl chnges. Although self-reported questionnires re frequently used to ssess children s personl nxiety or dentl fer [Spielberger et l., 1973; Cuthbert nd Melmed, 1982], the correltion of these questionnires with other physiologicl indices is uncler. Externl behviourl responses re generlly ssessed using behviourl scles such s the Frnkl Behviour Rting Scle (FBRS) [Frnkl et l., 1962]. Internl physiologicl chnges re typiclly evluted by mesuring hert rte nd blood pressure nd quntifying biomrkers in the blood, urine, or sliv during procedure [Miller et l., 1995]. However, the use of syringe to collect blood smples cn lso cuse physiologicl nd psychologicl stress for subjects. Thus, the issue of whether quntifying biomrkers in blood cn precisely evlute stress levels remins controversil. In ddition, urine nlysis for children requires coopertion from their gurdins. Sliv smpling, non-invsive procedure, mkes multiple smpling esy, nd does not cuse distress to the subjects. Alph mylse, which is one of the mjor slivry enzymes in humns, is secreted in response to sympthetic stimuli, nd increses during distress [Chtterton et l., 1996]. Thus, we mesured ptient levels of slivry lph mylse (saa), since it indictes n individul s internl physiologicl stte, nd cn be used s n index of psychologicl stress. We previously investigted the relibility of mesuring saa level s stress response biomrker in the clinicl setting, nd hve indicted its relibility [Aoygi et l., 2011; Kribe et l., 2011]. The ims of this pilot study were: to ssess levels of psychologicl stress nd personl nxiety during peditric dentl procedures in coopertive children; nd to compre coopertive children who showed Europen Journl of Peditric Dentistry vol. 14/4-2013 263
Kribe H. et l. psychologicl stress during dentl procedures nd those who did not in terms of dentl fer, personl nxiety, prentl fctors, nd dentl tretment fctors. Mterils nd methods Prticipnts The study popultion included 54 children (28 girls, 26 boys; men ge, 8.6 yers) who visited peditric dentl clinics in the Tokyo, Jpn re nd their ccompnying prents. Children with bnorml psychologicl development, developmentl retrdtion, pervsive developmentl disorder, severe sensorymotor impirment, nd slivry glnd disorder were not included. We lso excluded ccompnying prents if they hd slivry glnd disorders, mentl disorders, developmentl illnesses, or were using ny mediction tht could influence slivtion nd/or utonomic nervous system ctivity. The inclusion criteri required tht the children were between the ges of 8 nd 13, hd previously visited dentl clinic nd received dentl tretment, nd hd not been dignosed with n cute orl disese. After fully explining the purpose of the study to the children nd their prents, we obtined written consent to prticipte. This study ws pproved by the Ethicl Review Bord of the School of Life Dentistry, Nippon Dentl University, Jpn. All children received comprehensive dentl exmintion routinely provided in peditric dentl clinics by one of seven peditric dentists, including four femles nd three mles between 33 nd 68 yers of ge (verge ge = 50.9 yers) who were certified by the Jpnese Society of Peditric Dentistry. Before the initil consulttion, ll prents completed severl forms nd provided demogrphic nd helth history informtion. Before the comprehensive exmintion, we recorded detiled history of chief complint(s), ssocited symptoms, nd previous tretments received for the chief complint(s). Study design nd procedures We ssessed psychologicl stress levels in children nd their prents by mesured saa levels before nd immeditely fter dentl tretment. To ssess personl nxiety levels, the children completed the Stte-Trit Anxiety Inventory for Children Trit (STAIC-T) before tretment, nd the STAIC Stte (STAIC-S) before nd fter tretment (pre-staic-s nd post-staic-s) [Spielberger et l., 1973]. Prents completed the Stte- Trit Anxiety Inventory Trit (STAI-T) before their children s tretment, nd the STAI Stte (STAI-S) before nd fter their children s tretment (pre-stai-s nd post-stai-s) [Spielberger et l., 1970]. We ssessed dentl fer in the children nd their prents using the Children s Fer Survey Schedule Dentl Subscle (CFSS- DS) [Cuthbert nd Melmed, 1982] nd the Dentl Fer Survey (DFS) [Kleinknecht et l., 1973]. All psychometric tests used in this study were Jpnese versions, nd the vlidity nd relibility of these tests hve been verified [Nkzto nd Shimonk, 1989; Nki et l., 2005; Yoshid et l., 2009]. We recorded the children s nxiety levels, dentl fer, nd saa levels before tretment in the witing room, nd the saa levels fter tretment in the tretment room. We recorded the sme prmeters for prents in the witing room. We lso documented specific informtion relted to ech dentl tretment, including the number of dentl visits, time slot of the dentl visit, tretment time, ge/gender of the dentist, presence of the prent in the tretment room, course of dentl tretment, use of locl nesthesi, use of dentl drill, nd externl behviourl responses of the children. Two exminers ssessed the externl behviourl response of ech child during the dentl procedure using the FBRS [Frnkl et l., 1962]. Mesurement of saa levels In this study, we mesured saa levels using hndheld saa monitor (Nipro; Osk, Jpn). We collected sliv from prticipnts using disposble test strip positioned under the tongue for 30 s. We then inserted the test strip into the monitor nd recorded the saa level. The hnd-held monitor employs dry-chemicl system tht enbles mesurement of saa levels with high degree of ccurcy [Aoygi et l., 2011]. Previous studies hve shown extensive differences in saa levels mong individuls [Kribe et l., 2011]; therefore, we clculted the rte of chnge in saa levels between prend post-tretment in order to compre this biomrker. Clssifiction of the groups Our previous study [Aoygi et l., 2011] showed tht the men coefficient of vrince for the saa mesurement ws 7.2%. Thus, we set the cut-off point for the rte of chnge in saa levels between pre- nd post-tretment s ±10%. We divided children into the following two groups. 1. The incresed mylse (IA) group, consisting of children whose rte of chnge in saa level incresed more thn 10% during dentl tretment. 2. The decresed mylse (DA) group, consisting of children whose rte of chnge in saa level decresed more thn 10% during dentl tretment. Prents were lso divided into these two groups bsed on their children s rte of chnge in saa level, not their own rte of chnge in saa level. Sttisticl nlyses We evluted differences between the groups using the Student s t-test, Chi-squre test, nd Fisher s exct test. Before performing these comprisons, we ssessed gender-bsed differences nd vribility using the Student s t-test with significnce level of P 0.05. 264 Europen Journl of Peditric Dentistry vol. 14/4-2013
Psychologicl stress in coopertive children We used logistic regression model to estimte the odds rtio (OR) nd 95% confidence intervl (CI) for the predictive vlue of psychologicl stress during the dentl procedure. Vribles were considered for the multivrite models if their univrite P-vlues were <0.10. We preformed ll nlyses using SPSS 15.0J for Windows (SPSS Jpn Inc., Tokyo, Jpn). Results Of the 54 children who were enrolled, 28 were clssified into 2 groups: the nd the. The remining 26 children were excluded; 16 children were less thn 8 yers of ge; 2 children indicted uncoopertive behviour with FBRS scores of 2 (negtive) or 1 (definitely negtive) during the dentl tretment; 5 children showed less thn ±10% of rte of chnge in saa levels; nd 3 children hd missing items on the self-reported questionnire. There were no significnt gender-bsed differences in children with respect to ge, tretment time, number of dentl visits, saa levels, nxiety levels, nd dentl fer levels. Hence, we did not perform ny gender-bsed nlysis for the b P vlue saa c chnge rte (%) 95.0 ± 95.2-32.8 ± 15.0 - Age (yers) 9.6 ± 1.7 9.7 ± 1.7 0.83 Gender rtio (f/m) 6/8 11/3 0.12 tble 1 Smple chrcteristics in the 2 groups (men ± SD). Children whose rte of chnge in slivry lph mylse (saa) level incresed more thn 10% during dentl tretment b Children whose rte of chnge in saa level decresed more thn 10% during dentl tretment. c slivry lph mylse t-test nd Fisher s exct test children. Tble 1 shows the demogrphics of the study subjects, ctegorised by the 2 groups. On verge, children in the showed 95% increse in saa during dentl tretment, nd children in the showed 33% decrese in saa. However, no significnt differences in ge or gender rtio were found between the 2 groups. Tble 2 presents the men scores for dentl fer nd personl nxiety experienced by the subjects in ech group. The tble lso presents the ge nd the rte of chnge of saa in prents. Children in the scored higher for dentl fer compred to those in the, but the difference ws not sttisticlly significnt. The men score for the nxiety trit in the ws significntly higher thn tht in the (P = 0.021). Of the 14 prents in the, 13 were mothers nd 1 ws fther. The 14 prents in the were ll mothers. Prents in the showed 5% increse in saa during their children s dentl tretment, nd prents in the showed 29% decrese in saa, but the difference ws not sttisticlly significnt. In contrst to the children, prents in the scored higher for dentl fer thn those in the, but not significntly. All 28 children received bloodless dentl tretment without locl nesthesi. The 2 exminers ssessed children s hving FBRS scores of 3 (positive) or 4 (definitely positive), with 100% greement, indicting tht ll children were well-behved during their dentl tretments. Tble 3 shows comprison of dentl tretments between the 2 groups. The dentl tretments included orthodontic tretment, dentl prophylxis, topicl fluoride tretment, composite resin restortions, nd ppliction of pit nd fissure selnts. The prevlence of ech type of dentl tretment did not differ significntly between the 2 groups. Tbles 4 nd 5 present comprison of dentl tretment fctors between the 2 groups. There were P-vlue Children CFSS-DS score 29.1 ± 11.4 24.4 ± 6.7 0.19 STAIC-T b score 37.8 ± 9.3 30.9 ± 4.8 0.021 Pre-STAIC-S c score 28.1 ± 10.3 27.6 ± 9.3 0.88 Post-STAIC-S d score 25.7 ± 8.8 23.4 ± 4.3 0.39 Prents Age (yers) 43.4 ± 4.0 40.8 ± 4.7 0.13 Rte of chnge of saa e (%) 4.5 ± 74.2-29.1 ± 52.5 0.18 DFS f score 36.1 ± 14.4 48.3 ± 17.6 0.06 STAI-T g score 42.4 ± 12.9 43.8 ± 12.8 0.78 Pre-STAI-S h score 35.4 ± 7.2 36.7 ± 8.4 0.65 Post-STAI-S i score 34.6 ± 9.1 33.3 ± 8.2 0.70 tble 2 Comprison of individul nd prentl fctors between the 2 groups (men ± SD). Children s Fer Survey Schedule Dentl Subscle b Stte-Trit Anxiety Inventory for Children Trit c Pre-tretment Stte-Trit Anxiety Inventory for Children Stte d Post-tretment Stte-Trit Anxiety Inventory for Children Stte e slivry lph mylse f Dentl Fer Survey g Stte-Trit Anxiety Inventory Trit h Pre-tretment Stte-Trit Anxiety Inventory Stte i Post-tretment Stte-Trit Anxiety Inventory Stte t-test Europen Journl of Peditric Dentistry vol. 14/4-2013 265
Kribe H. et l. n (%) n (%) Orthodontic tretment 7 (50.0) 6 (42.9) 0.71 Dentl prophylxis 6 (42.9) 5 (35.7) 0.70 Topicl fluoride tretment 4 (28.6) 1 (7.1) 0.33 Composite resin restortions 2 (14.3) 3 (21.4) 1.00 Pit nd fissure selnts 1 (7.1) 2 (14.3) 1.00 Others 0 ( 0.0) 3 (21.4) 0.22 Number of dentl visits (times) 35.1 ± 34.6 21.1 ± 16.4 0.18 Tretment time (min) 24.1 ± 17.8 24.6 ± 15.7 0.95 Age of dentist (yers) 49.8 ± 14.7 52.8 ± 15.0 0.60 P-vlue P-vlue tble 3 Comprison of dentl tretments between the 2 groups. stinless steel crown restortion (1), scling (1), nd root cnl filling (1) Chi-squre nd Fisher s exct tests tble 4 Comprison of dentl tretment fctors between the groups (men ± SD). t-test n (%) n (%) Visit in the morning 2 (14.3) 4 (28.6) 0.65 Femle dentist 9 (64.3) 10 (71.4) 1.00 Presence of prent 6 (42.9) 5 (35.7) 0.70 More thn 2 tretments 6 (42.9) 6 (42.9) 1.00 Use of dentl drill 3 (21.4) 4 (28.6) 1.00 FBRS score = 3 3 (21.4) 3 (21.4) 1.00 P-vlue B Wld P-vlue OR b 95% CI c STAIC-T d score 0.144 4.755 0.029 1.155 1.015-1.314 Number of dentl visits 0.028 2.050 0.152 1.028 0.990-1.068 Constnt -5.631 5.525 0.019 0.004 tble 5 Comprison of dentl tretment fctors between the 2 groups. Frnkl behviour rting scle Chi-squre nd Fisher s exct tests tble 6 Logistic regression model for ssignment to. regression coefficient b Odds rtio c Confidence intervl d Stte-Trit Anxiety Inventory for Children Trit no significnt differences in terms of the number of dentl visits, tretment time, nd ge of the dentist between the groups. With regrd to the vrious dentl tretment fctors, time slot of dentl visit, gender of dentist, presence of prent in the tretment room, 2 or more dentl tretments t one visit, use of dentl drill, nd positive behviour rting, no significnt differences were found between the groups. Tble 6 presents the results of the logistic regression for contributing risk fctors for incresed saa during dentl tretment. For children with higher STAIC-T scores, the odds rtio for incresed saa during dentl tretment ws 1.16 (95% CI [1.02 1.31]). However, no other fctors significntly predicted the vlue of psychologicl stress during the dentl procedure. Discussion We ssessed levels of psychologicl stress nd nxiety sttes before nd fter peditric dentl procedures, s well s the levels of dentl fer nd nxiety trits in 8 to 13-yer-old children nd their prents. All of the children dpted to their dentl tretments, nd the men nxiety stte score for children decresed fter dentl tretment in both groups. However, in the IA group, 9 out of 14 children indicted more thn 50% increse in saa level during their dentl procedures. This indictes tht psychologicl stress response is present in some children who re coopertive during dentl procedures. Brnd [1999] reported remrkble individul differences in men crdiovsculr responses during comprble dentl tretment. Nmely, some ptients did not show ny chnge in hert rte or blood pressure (non-rectors), some showed limited increse in these prmeters (rectors), nd some ptients showed very mrked increse (hyper-rectors). Such results suggest tht there re significnt individul vritions in how people respond to stressful situtions. Dentists tend to believe tht children who re coopertive during dentl procedures do not experience ny psychologicl stress during tretment. However, the present dt suggest tht some peditric ptients do experience 266 Europen Journl of Peditric Dentistry vol. 14/4-2013
Psychologicl stress in coopertive children psychologicl stress despite being coopertive during dentl procedures. Therefore, these results highlight the necessity for dentists to reconsider their pproch to treting such children. Previous studies suggested tht prentl dentl fer ws positively correlted with the level of dentl fer in their children [Rntvuori et l., 2009; Lee et l., 2008]. In our study, the men CFSS-DS scores in the IA nd DA groups were not significntly different nd were similr to vlues reported s norml for Jpnese children (27.7 ± 10.6) [Nki et l., 2005]. Moreover, the men DFS score for prents in the tended to be higher thn those in the. A recent study indicted tht prents nd their 11 to 16-yer-old children could not recognise ech other s dentl fer [Luoto et l., 2010]. A structured review confirmed reltionship between prentl nd child dentl fer, but this reltionship ws most evident in children under 9 yers of ge [Themessl- Huber et l., 2010]. The present study did not include children under 8 yers old, s the subjects were required to complete the psychometric tests by themselves. This tctic my hve minimised prentl influence on their children s rtings of dentl fer. Despite the fct tht prents in the tended to show higher levels of dentl fer, they showed decresed rte of chnge in saa (-29.1%) compred to the prents in the (4.5%) during dentl tretment. Furthermore, scores for the DFS, STAI-T, pre- STAI-S, nd post-stai-s, nd the rte of chnge in saa for prents were not significntly different between the 2 groups. These results my indicte tht prentl dentl fer, nxiety, or psychologicl stress do not ffect the psychologicl stress in their children. An experimentl study reported tht physiologicl responses to fer-inducing conditions reflect the degree of dentl fer in ptients [Lundgren et l., 2001]. As mentioned before, ll of the children in our study dpted to their dentl tretments, nd men scores for the CFSS-DS in both groups were not significntly different. Unexpectedly, these results my indicte tht dentl fer in children does not ffect their psychologicl stress during dentl tretment. However, the men STAIC-T score in the ws significntly higher thn tht in the. The OR nd 95% CI lso showed tht the nxiety trit in children ws significnt contributing risk fctor for ssignment to the. A recent study indicted tht development of dentl nxiety is not necessrily ssocited with the nxiety trit [Fuentes et l., 2009]. Thus, from these results, the nxiety trit in children my influence their psychologicl stress during dentl procedures more thn their dentl fer. In our study, the children s dentl tretments did not differ sttisticlly between the 2 groups. Miller et l. [1995] investigted the drenl stress response to vrious dentl tretments in helthy dults. They reported tht cortisol levels mesured t the strt of dentl procedure decresed by the end in ptients undergoing sttic dentl procedures such s routine exmintions. Conversely, cortisol levels following extrctions were elevted compred to bseline cortisol recordings [Miller et l., 1995]. Children who received invsive dentl tretment with use of locl nesthesi were not included in our nlysis. Even so, children in the showed incresed saa levels during bloodless dentl tretment. Thus, the present findings re not consistent with the previous dult study, but show individul vritions in stress response. After compring tretment fctors between the 2 groups nd the results of the logistic regression model, we found tht tretment fctors such s number of dentl visits, tretment time, ge of the dentist, or prentl presence did not contribute to psychologicl stress during dentl tretment. However, we found significnt reltionship between the children s nxiety trits nd psychologicl stress during dentl tretment. A recent study reported tht behviour mngement problems in 2 to 8-yer-old children during dentl tretment ws ssocited with child s younger ge, negtive gurdin expecttions, presence of toothche, nd presence of nxiety [Xi et l., 2011]. Holst et l. [1988] reported 3 non-dentl predictors of behviour mngement problems in 3 to 16-yer-old children: problems during medicl visits, dentl fer in the prent, nd nxiety when meeting unfmilir people. These findings prtly support our results. Future studies involving more socil/ prentl fctors re necessry to elucidte other fctors contributing to psychologicl stress. When interpreting the present study, severl limittions should be considered. First, the 7 dentists who prticipted in this study were certified peditric dentists. Peditric dentists re better trined to tret children with behviour mngement chllenges thn re generl dentists. This might hve influenced the children s responses while undergoing dentl tretments. Future studies should include generl dentists to determine if children re differentilly ffected by their dentist s level of trining in working with children. In ddition, lrger cohort of coopertive children undergoing dentl tretment nd lrger cohort of peditric dentists re required to vlidte these results. Furthermore, s most of the prents in our study were women, our findings might not be brodly pplicble to exmining prentl responses to peditric dentl procedures s we primrily mesured mternl stress responses. In the future, more peditric ptients nd mle prents could be included in studies to explore psychologicl spects nd ssocitive reltionships relted to peditric dentl tretment. Conclusions Some children experience psychologicl stress Europen Journl of Peditric Dentistry vol. 14/4-2013 267
Kribe H. et l. during dentl procedures even when the stress is not mnifest behviourlly. Eight- to thirteen-yer-old well-behved children with high nxiety trit scores my experience high levels of stress during dentl procedures; however, prentl nd dentl tretment fctors my not ffect psychologicl stress in these children. In order to estblish reltionship of mutul trust with children undergoing dentl tretment, peditric dentists should consider the reltionship between personl nxiety nd psychologicl stress tht cn occur in ll ptients, both coopertive nd uncoopertive, during peditric dentl procedures. Acknowledgements We would like to express our pprecition to Drs. Hiroko Okbe, Yoko Hgiwr, Hiromi Yoneym, Kiyokzu Ogt, nd Eiw Ogihr for their vluble support. This study ws prtly supported by Grnt-in- Aid for Young Scientists No.20890239 from the Jpn Society for the Promotion of Science. References Aoygi K, Kribe H, Kwkmi T, Writ S, Shimzu K, Ogt K. Inter- nd introbserver relibility of the hnd-held monitor for mesuring slivry lph-mylse level. Clin Lb 2011; 57: 253-257. Arnrup K, Broberg AG, Berggren U, Bodin L. Tempermentl rectivity nd negtive emotionlity in uncoopertive children referred to specilized peditric dentistry compred to children in ordinry dentl cre. Int J Peditr Dent 2007; 17: 419-429. Brnd HS. Crdiovsculr responses in ptients nd dentists during dentl tretment. Int Dent J 1999; 49: 60-66. Chtterton RT Jr., Vogelsong KM, Lu YC, Ellmn AB, Hudgens GA. Slivry lph-mylse s mesure of endogenous drenergic ctivity. Clin Physiol 1996; 16: 433-48. Cuthbert MI, Melmed BG. A screening device: children t risk for dentl fers nd mngement problems. ASDC J Dent Child 1982; 49: 432-436. Eli I, Schwrtz-Ard D, Brtl Y. Anxiety nd bility to recognize clinicl informtion in dentistry. J Dent Res 2008; 87: 65-68. Frnkl SN, Shiere FR, Fogels HR. Should the prent remin with the child in the dentl opertory? ASDC J Dent Child 1962; 29: 150-163. Fuentes D, Gorenstein C, Hu LW. Dentl nxiety nd trit nxiety: n investigtion of their reltionship. Br Dent J 2009; 206: E17. Gustfsson A, Broberg A, Bodin L, Berggren U, Arnrup K. Dentl behviour mngement problems: the role of child personl chrcteristics. Int J Peditr Dent 2010; 20: 242-253. Holst A, Schröder U, Ek L, Hllonsten AL, Crossner CG. Prediction of behvior mngement problems in children. Scnd J Dent Res 1988; 96: 457-465. Kribe H, Aoygi K, Kod A, Kwkmi T. Chrcteristics of the slivry lph-mylse level in resting sublingul sliv s n index of psychologicl stress. Stress Helth 2011; 27: 282-288. Kleinknecht RA, Klepc RK, Alexnder LD. Origins nd chrcteristics of fer of dentistry. J Am Dent Assoc 1973; 86: 842-848. Klingberg G, Broberg AG. Dentl fer/nxiety nd dentl behviour mngement problems in children nd dolescents: review of prevlence nd concomitnt psychologicl fctors. Int J Peditr Dent 2007; 17: 391-406. Lee CY, Chng YY, Hung ST. The cliniclly relted predictors of dentl fer in Tiwnese children. Int J Peditr Dent 2008; 18: 415-422. Lundgren J, Berggren U, Crlsson SG. Psychophysiologicl rections in dentl phobic ptients during video stimultion. Eur J Orl Sci 2001; 109: 172-177. Luoto A, Tolvnen M, Rntvuori K, Pohjol V, Lhti S. Cn prents nd children evlute ech other's dentl fer? Eur J Orl Sci 2010; 118: 254-258. Miller CS, Dembo JB, Flce DA, Kpln AL. Slivry cortisol response to dentl tretment of vrying stress. Orl Sur Orl Med Orl Ptho, Orl Rdiol Endod 1995; 79: 436-441. Nki Y, Hirkw T, Milgrom P, Coolidge T, Heim M, Mori Y, Ishihr C, Ykushiji N, Yoshid T, Shimono T. The Children's Fer Survey Schedule- Dentl Subscle in Jpn. Community Dent Orl Epidemiol 2005; 33: 196-204. Nkzto K, Shimonk Y. Jpnese Stte-Trit Anxiety Inventory: ge nd sex differences. Percept Mot Skills 1989; 69: 611-617. Rntvuori K, Tolvnen M, Husen H, Lhti S, Seppä L. Fctors ssocited with different mesures of dentl fer mong children t different ges. J Dent Child (Chic) 2009; 76: 13-19. Spielberger CD, Gorsuch RL, Lushene RE. STAI Mnul for the Stte- Trit Anxiety Inventory ( Self-Evlution Questionnire ). Cliforni: Consulting Psychologicl Press, Inc; 1970. Spielberger CD, Edwrds CD, Lushene RE, Montuori J, Pltzek D. STAIC Preliminry Mnul for the Stte-Trit Anxiety Inventory for Children ( How I feel questionnire ). Cliforni: Consulting Psychologicl Press, Inc; 1973. Themessl-Huber M, Freemn R, Humphris G, McGillivry S, Terzi N. Empiricl evidence of the reltionship between prentl nd child dentl fer: structured review nd met-nlysis. Int J Peditr Dent 2010; 20: 83-101. Yoshid T, Milgrom P, Mori Y, Nki Y, Kji M, Shimono T, Donldson AN. Relibility nd cross-culturl vlidity of Jpnese version of the Dentl Fer Survey. BMC Orl Helth 2009; 9: 17. Xi B, Wng CL, Ge LH. Fctors ssocited with dentl behviour mngement problems in children ged 2-8 yers in Beijing, Chin. Int J Peditr Dent 2011; 21: 200-209. 268 Europen Journl of Peditric Dentistry vol. 14/4-2013