1?, \t.cR t The Effect of Myofunctional Therapy in Anterior Open Bite Patients Measured by Electropalatography A S Cayley Submitted in partial fulfilment of the Degree of Master of Dental Surgery University of Adelaide 1998 sluoluoc t CONTENTS 2 1.1 Table of Contents 1. Contents 1 1.1 Table of Contents. 1.2 List of Tables....... 4 1.3 List of Figures...... 2. Abstlact 3. Acknowledgements.............. 9 4. Introduction & Aims............ T2 4. 1 Introduction.......... 13 4.2 Aims... t4 4.3 Null hypotheses... ..t4 5. Literature Review 15 5.1 Anterior open bite t6 5.2 Tongue thrust....... ..29 5.3 Relationship between anterior open bite & tongue thrust ..38 5.4 Measurement of tongue function ..39 5.5 Corrective therapy ..42 ..44 6. Materials & Methods.............. ..................45 6.1 Introduction. ..................46 6.2 Sample 46 6.3 Plate construction................. 51 6.4 First electropalatoglaphic (EPG) recording......... ..53 6.5 Tongue re-education therapy ..54 6.6 Second electropalatographic (EPG) recording .... ..................54 6.7 Analysis ..................54 6.8 Assessment of reproducibility ..................6 1 CONTBNTS 3 7. Results.. ..62 7.1 Introduction.. ,.63 7.2 Tongue re-education therapy report......... ..64 7.3 Radiographic error study. ..66 7.4 Control & pre-therapy cephalometric data............ ..68 7 .5 Pre- & post-therapy cephalometric data................ ..73 7.6 Control & pre-therapy electropalatographic data.. ..79 7 .7 Pre- & post-therapy electropalatographic data...... 104 8. Discussion.. t28 9. Principal Findings.. 150 10. Appendices ........... ..............154 10.1 Appendix 1.'Word list used for EPG recording sessions... ..............155 10.2 Appen dix 2. Phonetic notations... ..............r57 10.3 Appendix 3. Individual cephalometric values ..............158 10.4 Appendix 4. Palatograms summarising EPG data. r62 11. References.. 172 CONTENTS 4 1.2 List of Tables Table 1 Plevalence of anterior open bite reported in the literature 18 Tabte 2 Brauer & Holt's classification of tongue thrust...... 29 Table 3 Tulley's classification of tongue thrust 30 Table 4 Prevalence of tongue thrust swallow by age 31 Table 5 Cephalometric landmarks used & their definitions 48 Table 6 Angular & linear measurements used in cephalometric analysis............ 49 Table 7 Subset of closules subjecæd to detailed analysis 58 Table 8 Classification & description of closures selected for analysis................ 59 Table 9 Words selected for analysis................ 60 Table 10 Time elapsed between first EPG recording, tongue re-education therapy visits & second EPG recordit g ............ 65 Table 11 Results of cephalometric error study......... 67 Table 12 Means & standard deviations of cephalometric variables for control group & experimental group befole therapy..... 72 Table 13 Means & standald deviations of cephalometric variables for experimental group before & after therapy 78 Table 14 Closure frequency of control group (by frequency)............ 82 Table 15 Closule frequency of expelimental group before therapy (by frequency) 83 Table 16 Closure frequency for control group & experimental group before therapy (by closure type)......... 84 Table 17 Mean durations of selected closurcs for control group & experimental group before thelapy...... 86 Table 18 Mcan ANR of selected closures for control group & experimental group before therapy 90 Table 19 Mean closure indices of selected closures for control group & experimental group before thelapy...... 94 Table 20 Mean ANR of selected words for control group & experimental group before thelapy .............;.... 96 Table2I Mean ANR of saliva & water swallows for control group & experimental gloup befole therapy.... t02 CONTENTS 5 Table 22 Closure frequency of experimental group before therapy (by frequency) r07 Table 23 Closure fi'equency of experimental group after thelapy (by frequency) 108 Table 24 Closure frequency for expetimental group before & after therapy (by closure type)......... Table 25 Mean durations of selected closurcs for experimental group before & after therapy...... 111 Table 26 Mean ANR of selected closures for experimental group before & after thelapy................ ..115 Table 27 Mean closure indices of selected closures for experimental group before & after therapy ..118 Table 28 Mean ANR of selected words for experimental group before & after therapy................ ..tzt Table 29 Mean ANR of saliva & water swallows for experimental group before & after therapy 125 Table 30 Means & standard deviations of U1-SN & IIA from University of Iowa growth study & present study......... Table 31 Mean values & standard deviations of soft tissue variables for control group & experimental group before & after therapy.... 132 Table 32 Mean duration & ANR values for control & experimental group subjects before thelapy for ltfl e.leJ closures Table 33 Mean dulations of voiced & voiceless closure pairs for control gloup & experimental group before & after therapy..... .........142 Table 34 Mean ANR fbl all swallows for allgroups.... 148 Table 35 Phonemes & IPA symbols used tbr notation of closures .......I57 Table 36 Individual cephalometric values for control group subjects 159 Table 37 Individual cephalometric values for expedmental group subjects befole therapy...... 160 Table 38 Individual cephalometric values for expedmental group subjects L6t CONTENTS 6 1.3 List of Figures Figure 1 Cephalometric landmarks with linear & angular measurements.... 50 Figure 2 EPG plate.... 52 Figure 3 Palatograms with mean duration values in milliseconds for 8 selected closures fol control & pre-therapy experimental groups.. 87 Figure 4 Palatograms & mean ANR values for 8 selected closures for control & pre-therapy experimental groups ......., 9r Figure 5 Palatograms & mean ANR values for 'desk', 'measure', 'tooth', 'tune' &'zip' for control & pre-therapy experimental groups ........ 97 Figure 6 Palatograms & mean ANR values for 'box', 'castle', 'chain', 'dredger', 'clock' &'Ieg' for control & pre-therapy experimental groups 99 Figure 7 Palatograms & mean ANR values for saliva & water swallows for control & ple-therapy experimental groups ............... ..r02 Figure 8 Palatograms with mean duration values in milliseconds for 8 selected closurcs for experimental group before & after therapy....... ..112 Figure 9 Palatograms & mean ANR values for selected closures for experimental gloup before &. after thelapy ..116 Figure 10 Palatograms & mean ANR values for 'box', 'slipper', 'desk', 'dt'edget', 'team', 'tune', 'joke', 'nose' & 'thong' for experimental group before & after therapy.... r22 Figule 11 Palatograms & mean ANR values for saliva & water swallows for experimental group subjects before & after therapy .r25 Figure 12 Palatograms & mean ANR values for 'chain', 'dredger' & 'clock' fì'om control group & experimental group before & after therapy..... r31 Figure 13 Palatograms for lW e. /{/ closures from control & pre-therapy experimental groups ... r39 Figure 14 Palatograms fbl words containing the /s/ phoneme for control & pre-thelapy expedmental gloups...... r40 Figure 15 Palatograms & mean ANR values for ltJ,lnl,lfl,lül,lW & lgl for control group & experimental gloup before therapy..... r44 Figure 16 Palatograms & mean ANR values for saliva & water swallows for control group & experimental group before & after therapy 147 lcerlsqv 'z AssrnRcr 8 Anterior open bite (AOB) and tongue thrust swallowing are frequently associated, but the relationship between the two remains unclear. Anterior tongue posture may prevent the eruption of the anterior teeth, and myofunctional therapy (MFT) is often prescribed for the correction of tongue thrust swallowing, with the expectation that AOB will reduce spontaneously if a more posterior tongue posture is learned. However, the effectiveness of MFT has not been subjected to systematic evaluation. Electropalatography (EPG), which is widely used in speech pathology to measure dynamic tongue function for diagnostic, therapeutic and research purposes, is a suitable technique for the assessment of MFT. This plospective clinical study examined dento-facial patteln and tongue function in AOB and non-open bite children, and assessed the effect of tongue re-education therapy on dento-facial form and tongue function in AOB patients. EPG recordings of speech and swallowing, and lateral head radiographs were obtained from 8 ten year old boys with tongue thrust swallowing behaviour and AOB, and 8 age matched non-open bite controls. Analysis of data from the two gloups indicated that although diff'erences were small, the open bite children displayed tlends for longer face morphology and greater upper incisor proclination, less consistent production of closures during speech, a more posterior pattern of EPG contact, and relatively sparse EPG contact during swallowing. Comparison of the conclition of the AOB children before and after a course of tongue te-education therapy showed little cephalometric change, but there was some evidence of a trend for upper and lower inci.sor etuption, with concomitant reduction of the AOB' A trend for more consistent, and more anterior pattern of EPG contact after therapy was also found. After therapy, the experimental children more closely resembled the controls, implying that the therapy was at least partially successful. 3. Acknowledgements ACKNOWLEDGEMENTS 10 I would like to express my sincere gratitude to Professor Wayne Sampson, both for his assistance, and for his willingness to help and