Changes In Class I1 Malocclusions with AndWithout Occipital Headgear Therapy*DONALD R. POULTON, D.D.S.Sun Francisco, Calif.INTRODUCTIONThe current interest of the ortho-dontic profession in extraoral force isreflected by the numerous reports on itsuse which have recently appeared. Theapplication of this force to the upperdental arch is considered by many tobe the treatment of choice in Class 11,Division 1 malocclusion, the most prev-alent malrelation of the jaws. An im-portant factor has been the realizationthat treatment of Class I1 cases with-out. extraoral force can rarely be ac-complished without some forward dis-placement of the lower dental arch.As investigators come to place great-er emphasis on objective measurementand less on clinical impression, theappliance should become clear. Sinceit is generally accepted that there is nobetter method of accurately recordingthe changes due to facial growth andorthodontic therapy', roentgenographiccephalometry was used for the inter-pretation of treatment results. In anyattempt to compare the conclusions ofvarious investigators on this problem,the appliance used, the length of ther-apy, the type of sample and the de-gree of patient cooperation must becarefully evaluated. In this report,changes in a group of Class I1 patientstreated with an occipital headgear willbe compared with changes in a similarI:-:*-.*:--,.llllIILac,"IIJ and p"""ii!ities sf ?. givenDivision of Orthodontics, University ofCalifornia School of Dentistry, San Fran-cisco, Calif.*Presented before the meeting of theNorthern California Component of the Ed-ward H. Angle Society, October 9, 1958.but untreated group at the end of atwelve-month period.This uniform period of study eliminat-cd some of the variability in the amountof growth occurring during the periodof observation. The studies on extra-oral force by Epstein', Graber", andKing4 are based on records taken four-teen months to four years apart andthus, some details of tooth movementand facial change may have been ob-scured. The ultimate importance of thechanges observed in this report can beevaluated only by the future study ofthe dental relationships which have re-mained stable in these patients over athree or four year period. This projectwas designed to show as clearly aspossiblc the changes in a group of pa-tients treated with an occipital head-gear appliance.MATERIALMost cephalometric evaluations oforthodontic therapy have relied onstudies of normal dentofacial growthand development to distinguish be-tween treatment and growth changes.Investigations such as those of Brodie5and Bjijrk' have provided the corner-stones of knowledge in this field. Whilestudies in malocclusion cases have notcstablished a growth pattern differentfrom the normal, an investigator can-not predict in detail growth changeswhich will occur in the sample of caseshe may have under treatment. Thenced to study an untreated group com-parable in every way to the patientsundergoing treatment was pointed out234 Vol. 29. No. 4Headcap Therapy235Fig. 1, Typical malocclusions.by Klein7 in his study of extraoralforce therapy.Treatment GroupPatients were accepted into thisstudy on the basis of possessing thefollowing characteristics :1. A Class 11, Division 1 maloc-clusion. The severity of Class I1molar relation varied from cuspto cusp occlusion to extreme casesin which the upper molars weremore than a whole cusp forward(Fig. 1). Even in the less severecases, the Class I1 relation wasnoted to be present in the canineand premolar areas.2. An occlusion in the mixed denti-tion stage of development.3. A lower dental arch in accept-able alignment and in good rela-tionship to the mandibular base.4. A malocclusion not complicatedby prematurely lost deciduous orpermanent teeth.The mean age of the twenty-nine 236 Poulton October, 1959cases in the treatment sample was 10years 4 months at the beginning oftreatment and consisted of: eighteenmales, ranging from 8 years 9 monthsto 11 years 11 months of age, andeleven females, ages ranging from 8years 3 months to 11 years 1 month.Control groujThe control group was assembledfrom the case records of the Philadel-phia Center for Research in ChildGrowth, through the courtesy of Dr.W. M. Krogman. The enthusiastic co-operation received from this sourcepivz our study a sample matching thetreatment group in age, sex, den-tal stage and type of occlusion. Al-though an individual treated and con-trol case cannot be directly compared,each treatment case was matched witha control case of the same age and sexto assure the comparability of the two~Ioups. Both samples are composed ofwhite Caucasian stwk predominantlyMediterranean in origin.The comparison, then, is betweentwo groups of children with similarmalocclusions, identical in sex and age.Subsequent annual evaluations will bemade of the changes in both groups,thereby increasing our knowledge ofthe extent to which the dentofacial pat-tern can be altered.APPLIANCE THERAPYThe intraoral appliance consisted ofbands with edgewise attachmentsplaced on the upper first permanentmolars and the four upper incisors.A .021 x .025 archwire was used withhooks for attaching .the headgear dis-tal to the central incisors. Since all ofthe upper teeth were to be movedposteriorly with as little change inaxial inclination as possible, it was im-portant to have torque control overthe upper incisors; the edgewise archwas placed with active lingual roottorque in the anterior region. StopsFig. 2.on the archwire mesial to the molarsconsisted of short sections of pushsprings slightly activated by Russelllocks. This permitted ease of adjust-ment in changing the relative amountof force directed against the molarsand incisors. No appliances were placedin the lower dental arch in any case.The headgear itself is a commer-cially fabricated appliance that is lightand easiiy adjusted (Fig. 2j. Ciothstraps pass both above and below theear from a rigid plastic section on thecheek, and active force is supplied byelastics attached both to the plasticsection and to hooks linked on thearchwire. The patients reported thatthe appliance was reasonably com-fortable and that no difficulty was en-Fig. 3, This patient is typical of those inwhom the position of the lower headstrapin relation to the ear prevented any higherangle of pull. Vol. 29. No. 4 Headcap Therapy 237countered in sleeping with it in place.It was noted that adjustment waslimited because the position of thelower strap passing beneath the ear pre-vents an effectively high angle of pullin some patients. (Fig. 3)The treatment objective was to pro-duce the maximum amount of desir-able change in the shortest period oftime, while keeping the appliance un-complicated and not in need of fre-quent adjustment.The excessively long period of treat-ment required by therapeutic methodsstressing minimum tooth movementand maximum reliance on growth hasbeen cited as a serious deterrent tosatisfactory patient cooperation, op-timum treatment results and efficientoffice management'. Therefore, treat-ment was directed at producing distalbodily movement of the upper teethand correction of any rotation andspacing in the upper anterior segment.PATIENT COOPERATIONIt was known from the start thatpatient cooperation was essential, andtherefore a method of checking thisfactor was incorporated into the de-sign of the experiment. Charts design-ed for the easy recording of hours ofdaily headgear wear (Fig. 4) were at-Fig. 4. The lower time chart has beenfilled m by a patient for a three weekperiod; the upper unmarked chart is stapledto the envelope in which the headgear iskept.tached to the envelope in which theremovable portion of the appliancewas kept. The recorded hours werechecked and tabulated at each patientvisit. It was repeatedly stressed to eachpatient and parent that accuracy inkeeping these records was far moreimportant than merely showing a goodrecord. After considerable experiencewith these charts it was felt that wehad a reliable and accurate methodof recording patient cooperation.Patients were instructed to wear theheadgear appliance a minimum oftwelve hours a day and more ifpossible. The average amount of head-gear wear vaned in individuals fromten to fourteen hours per day withan overall average of 12.3 hours. Itwas noted that with few exceptionsonce a pattern of headgear wear hadbeen established for an individual, theaverage number of hours per day didnot vary greatly during the treatmentperiod.METHOD OF MEASUREMENTLateral films taken in the Broad-bent-Bolton cephalometer were thebasis for all measurements on bothtreatment and control samples. Theinitial film and that taken one yearlater in each ind.ividua1 were tracedaccording to standard cephalometricprocedures and measurements made bydirect comparison of the two tracings.For this study, the tracings weresuperimposed on a non-growing areaof the cranium rather than on a planedetermined by points which move withgrowth. This was done by utilizing theline originally described by Keith andCampiong and introduced into roent-genographic cephalometrics by De Cos-terl0. The line is formed by the an-terior border of sella turcica, theplanum, the superior surface of theethmoid plate and the inner surfaceof the frontal bone (.Fig. 5). It has 238Paulton October, 1959Superposition L meFIGURE 5FIGURE 5Fig. 5. The location of points used formeasurement and the cranial base line usedas the basis of superposition iu this study.The points were duplicated on subsequenttracings by superimposing contours of theindividual teeth and jaws.been utilized by Bjorkl' and can beconsistently located in serial films. Theentire contour of the line can be super-imposed on films taken after sevenyears of age, giving a good basis oforientation for comparative purposes.In some cases, difficulty was encoun-tered locating the line in the ethmoidplate area. It was noted that orienta-tion could be made more consistentalso by superimposing on the line whichextends from basion superiorly andforward along the lesser wing of thesphenoid to the cranial base.Linear millimeter measurementswere used to determine the change inposition of the features studied here.The use of angular readings for thispurpose tends to be less exact becauseof the many variables which may af-fect an angle. A decrease in the sizeof the angle SNPo, for instance, mightmean that point Po moved backward,but it could also mean a forward orsuperior movement of point N. Angleswhich are smaller, such as the SN-upper molar angle, are even moresusceptible to this sort of difficulty ininterpretation.In comparing the increments meas-ured in this study with those of anothergsoup, the age range, time span andcephalometric technique used must beborne in mind. Superposition of trac-ings with registration on the SN planeat sella as employed by Bjork'l wouldbe essentially the same, while theregistration at nasion used by Landel'and Steiner13 would greatly reduce thehorizontal anterior measurements.Registration by the methods of Broad-bent14 or Ricketts15 would show thesame proportional changes in the aver-age case, but would reduce both hor-izontal and vertical measurements.Since we superimposed a non-growingarea and compared treated and un-treated cases, no assumption concern-ing amount or direction of growth wasnecessary.Points A and B, the subjects of muchrecent cephalometric investigation,were not included here. It was foundthat point pogonion gives a more ac-curate indication than point B of theposition of the anterior portion of themandibular body. The location ofpoint A yielded no new informationsince both the upper incisor and themaxillary body positions were meas-ured directly. Observations in treatedcases showed a marked thickening ofthe labial alveolar process due to lingu-al movement of the upper incisors(Figs. 10 and 12) and thus, laterthinning of the bone on which pointA is located may be expected. Theposttreatment changes in point A posi-tion will be one of the important ob-servations to be made on these patientsin subsequent reports.The effect of occipital headgeartreatment was determined by measur-ing changes in position of the follow-ing points (Fig. 5) : Vol. 29. No. 4 Headcap1. MC and MA, the crown and theroot apex of the maxillary first per-manent molar, horizontal measure- ment.2. IC and IA, the crown and the rootapex of the maxillary central in-cisor, horizontal and vertical meas- urement.3. MB, drawn near the center of thehard palate outline, indicating thelocation of the maxillary body, hor-izontal measurement.4. Po, the anterior mandibular body,horizontal and vertical measure- ment.Each of these points was drawn on atooth or jaw to represent the positionof that portion of the dentofacial com-plex at the time of the initial film.The outlines of the same individualstructures seen in subsequent filmswere then superimposed on the originaland the point reproduced by tracing.The exact location of any point on theoriginal tracing is not critical for onlythe movement of the point is measur-ed, indicating movement of the struc-ture on which the point is located. Theonly point which was not easily andconsistently reproduced was MB (max-illary body) because of the difficultyin visualizing anterior nasal spine andnasal floor contour and the changesin alveolar contour during the periodof changing dentition and orthodontictreatment. The original facial plane(NPo) was the vertical axis on whichall positional changes were based ; hor-izontal changes were measured at rightangles to this plane.Two additional measurements weremade showing growth over which thetherapy was not expected to have anyeffect :5. Lengthof the line from sella turcicato nasion.6. Length of the mandible; measuredbetween points Po and Ar (definedby Bjork'). This is the effectivemandibular length as employed byTherapy 2 39Blair1' and is a modification ofWylie'sl' method.During the course of this study mostof the tracings were done twice tocheck the limits of accuracy and itwas determined that no measurementless than the nearest whole millimetercould be repeated consistently, as point-ed out by Graberl*. Since all films weretaken using the same technique, the useof a correctional scale was not in-dicated ( Higleylg).FINDINGS OF CONTROL GROIJPIn reporting the lineal changes, thediscussion is centered on the meanvalue or average behavior of the pointin question. This procedure has beencriticized when applied to certaintypes of data in the orthodontic liter-ature as ignoring the individual pat-tern and presenting only an unrealaverage pattern. The use of averagevalues is justified here because thevariables affecting the measurementhave been held to a minimum and thereadings from most of the individualcases follow rather closely the meantrend.The changes occurring over twelvemmths in the group of untreated ClassI1 malocclusions are shown in Table I.Fig. 6 is a composite showing themean changes occurring within thisgroup. It indicates that the mandiblegrew forward somewhat more than themaxilla and upper face and that thedentition, both upper and lower, mov-ed forward at least as much as thelower jaw. In this group it was ob-served that anteroposterior relation-ships within the dentition remainedconstant for both the erupted teethand the unerupted bicuspid and cuspidtooth buds. No significant changes inocclusion occurred.It would be unwise to makeany generalizations about dentofacialgrowth and development from a one- 240Poulton October. 1959 TABLEl ICHANGE DURING ONE YEAR IN UNTREATED GLASS I1 CASESMean (mm) S.D. (mm)Range (mm)FOI3WARD CHANGES Molar crown 1.4 .7 0 to 3 Molar apex 1.2 .9 0 to 3 Incisor crown 1.3 .8 0 to 3 Tncisor apex 1.3 .9 0 to 3 Maxillary body 0.7 .7 0 to 2 Pogonion 1.1 1.1 -1 to 3DOWNWARD CHANGES Incisor crown 1.2 .6 0 to 3 Pogonion 1.5 1.1 0 to 5LENGTHENING CHANGES Sella to nasion 0.9 .6 0 to 2 Mandible 1.7 1.0 0 to 5F(GURE 6Fig. 6. A graphio construction of thechanges recorded in Table 1. It shows the:average growth changes over one year in29 untreated Class I1 (1) caaes with aninitial mean age of 10.3 years.year study of twenty-nine cases. How-ever, the slight increase in mandibularprominence which was noted is con-sistent with the findings of Bjork' andLandel?. If these mean growth changesoccurred in every Class I1 patient un-der treatment, it would seem that arelatively small amount of occlusal al-teration and distal pressure on the up-per arch could disturb the synchronousforward movement of the dentitionand allow improvement in arch rela-tionship to occur. Our dilemma is thatthese changes do not occur in everycase. The extremes in favorable andunfavorable growth occurring in theuntreated sample as shown in Fig. 7,would almost certainly have shown awide difference in response to an iden-tical orthodontic treatment procedure. CLINICAL RJXPONSE OF TREWMENT GROUPClinically, the headgear was eff ec-tive in changing the molar relationshipdid not attain full molar correction in12 months time and nearly all the pa-tients showed a substantial decrease inincisal overjet. Fig. 8 shows the or-iginal and one-year progress models onseveral of the patients.In the hope of finding factors toexplain the wide difference in the speedof clinical response, the cases weredivided into three groups on the basisof treatment time. Placement in therapid, intermediate or slow group de-pended on the number of months re-quired for correction and on theamount of original discrepancy inmolar relationship. Information whichwas analyzed for each group includedthe sex, chronological age, develop-mental age (from wrist film analysis)and dental maturity. The type andseverity of facial skeletal deviation pro-ducing the Class I1 and the prevalenceof this condition in other members ofthe immediate family were also re-corded. None of these factors showedte C!g.. 1. On!y fnl_?r cases in the st11dyMean lZmo changesUnfreated Graup Vol. 29, No. 4Headcap l'lieIapy24 1Control H G.11-23-53 -Control EL.Il-12-5f -10-25-52 ----IS ,12-3-54 ----ME -0MA -0 IA- I MB-2MA-2 IA -3MC-93 IC -3, el MCAO IC-Z.tlPo -3, t2Po -I, tlFIGURE 7Fig. 7. Tracings of two individual untreated cases demonstrating extremes in the amountand direction of facial growth during one year. M2rknrl differences in response to ortho-dontic treatment could be expected.any significant difference among thethree groups. From the variability seenin this study, any trends which mightexist among these factors could bedemonstrated only on a very largetreatment sample.As analysis of the study proceeded,the difference between the groups ingrowth and cooperation became ap-parent and data on these factors isshown in Table 11:Upper facial growth (S to N) wasnot critical to treatment speed, butthe fast treating group averaged twiceas much mandibular growth as theslow. This simply reconfirms what hasbeen said countless times about thebeneficial effects of mandibular growthduring the treatment of Class I1 mal-occlusion. From the data recorded hereit would not be possible to predictwhen this growth would occur. If thestudy of various maturation criteriaeventually leads to the prediction offacial growth timing, the efficiency oforthodontic treatment can be greatlyincreased. TABLE I1SIGNIFICANT FACTORS IS SPEED OF TREATMENT RESPONSE Rupia Intermediate Group Group 0.9 mmGROWTH s to N 1.0 inn1 3landiblo 3.4 mm 1.4 mmCOOPERATION Hours I day 13.9 hrs. 12.2 hrs.Inconsistent 0% 13 %No. cases 10 11SlowGroup1.0 mm1.2 mm11.9 hrs.37 %8 242PoultonFig. 8. Changes afterData on cooperation were obtainedfrom the time charts described be-fore and show that the averagenumber of hours of headgear wear didnot differ greatly among the groups.Although a slight trend exists, the dif-ference between the mean hours ofthe fast and slow group was not statis-one year of treatment.October, 1959tically significant.The other factor which was notedon these charts is summarized in TableI1 as percentage of "inconsistent" wear-ing of the appliance. Some patientsfailed to wear the appliance regularlydue to various circumstances includingillness, local complaints involving ir- Vol. 29. No. 4 Headcap Therapy 243 TABLE I11UHANGE DURING ONE YEAR OF OCCIPITAL HEADGEAR TREATMENTMean (mm) S.D. (mm) Range (mm)FOXWARD CrHANGE'S Molar crown -2.3 1.7 0 tQ -7Molar apex -1.6 1.0 0 to -4Incisor crown -2.3 2.3 2 to -9Incisor apex -1.1 1.0 1 to -3Maxillary body 0.1 0.8 1 to -1Pogonion 0.4 1.4 3 to -2DOWNWARD CHANGES Incisor crown 2.3 1.8 0 to 6 Pogonion 2.6 1.G 0 to GLENGTHENING CHANGE,S Sella to nasion 0.9 0.5 0 to 2ritation or appliance adjustment, andother less plausible excuses. With a fewpatients it became obvious that thetime charts were not honestly markedand questioning of patient and parentrevealed breaks in routine which werethen noted on the chart. The per-centage recorded in Table I1 reflectsthc number of time charts in that groupwhich showed lapses in headgear wearof three or more days. Wearing theheadgear every day would appear tobe very important for most effectiveMandible (Po-Ar) 1.7 1.0 0 to 5Meon ,2 mo, cnongesHwdgear TIeo,men, G,oup MB-JMA.c/,6 rA-/,treatment. MC-2.3 IC-2.3. IPO+ .4,f2.6CEPHALOMETRIC FINDINGSChanges occurring in the group ofClass 11, Division 1 cases treated withan occipital headgear for 12 monthsare showr! in Table 111.Fig. 9 is a composite illustrating themean changes recorded in Table 111.In the table, minus values in the "For-ward Changes" column indicate mil-limeters of distal movement. Molarcrowns averaged 2.3 mm distal move-ment, and in one case, 7 mm of distalmolar movement was recorded. Distalmolar root movement averaged 1.6mm; no mesial root movement wasfound in any case under treatment.Posterior movement of the central in-cisor crowns averaged 2.3 mm as didthe molars, but individual cases show-ed more variation, ranging from 9mmposterior movement to 2 mm anteriormovement. Only 1.1 mm average pos-FIGURE 9Fig. 9. A graphic construction of thechanges recorded in Table 3. It shows theaverage treatment and growth changes overono year in tho twenty-nine Class I1 (1)patients treated with occipital headgear.terior incisor root movement was ob-tained, although individual cases show-ed up to 3 mm.By comparing these values with therelatively small amount that pogonioncame forward, 0.4 mm, one can readilysee that by far the greatest part ofthe occlusal correction was due to dis-tal movement of the upper teeth. Fig.10 shows the twelve month changes intwo of the cases. An important ob-servation in both of these cases is thatby using an appliance which movedthe roots lingually, a significant pos-terior movement of the unerupted cus- 244PoultonOctober, 1959Patie,it B. N.4-4- 57 -4-1 - 58 ----Patient N. K.FIGURE 10Fig. 10. Tracings of two pat.ients undergoing headgear treatment. Posterior movement ofthe molars and incisors as well as the cnspid and bicuspid buds can be seen.pid and bicuspid tooth buds was ob- what actually happened in the treat-tained. Upper tooth buds were moved ment group, the difference between theposteriorly about the same distance as treatment and control groups is morewere the upper molar roots in every important. Table IV shows this dif-case. ference and reflects the treatmentchange without the growth change;that is: Table I11 values minus TableNET CHANGES PRODUCEDWhile the values in Table I11 showI values.TABLE IVDTFFERENCX IN ONE YEAR BETWEEN TREATED AND UNTREATEDCLASS I1 CASESFORWARD CHANGESMolar crowiil\[olar apexIncisor crownIncisor apesMaxillary boil!.PogonionDOTVNW A RlJ GHBNGESLEXGTHENING CHANGES Sella to nasionIncisor crownPogonionMandible (Po-Ar)Direrenee-3.7-2.8-3.6-2.4-0.6-0.71.11.10.00.0 Vol. 29. No. 6 Headcap Therapy 245FIGURE /IFig. 11. A graphic construction of the dif-ferences between treatment and controlgroups as recorded in Table 4. The positionsof the teeth and jaws under treatment arecompared with the positions they would haveoccupied without treatment.The degree of individual variationwas such that treated and untreatedcases could not be compared on anindividual basis, but valid conclusionscan be drawn from the statistical com-parison of large enough samples. Fig.11 is a graphic representation of thegroup differences as seen in Table IV.It shows where the teeth and jaws wereas compared with where they might bepresumed to have been without treat-ment.Posterior movement of upper teeth,the primary goal of treatment, was wellaccomplished. The entire maxillarydentition, including both the eruptedand the unerupted teeth, was about 3mm farther back than it would havebeen without treatment.It was hoped that this movementcould be obtained without the excessupper incisor extrusion and increasein lower face height which often occurduring Class I1 correction procedures.Incisor extrusion tends to increase thevertical overbite, which initially is of-ten deep in a Class I1 case. The ex-cessive downward movement of thechin is really an opening swing of themandible, resulting in an inhibition ofthe normal forward chin progress.Even though this retardation is slight,it may accentuate the retrusive profilecommon in Class I1 malocclusion. Theexcess vertical movement found in thisstudy was 1.1 mm for both the incisorand the chin. This resulted in a re-tardation of forward pogonion move-ment of 0.7 mm on the average. Inthe case shown in Fig. 12, where down-wa.rd movement was 4 mm and man-dibular growth was slight, a 2 mmposterior movement of pogonion oc-curred.The lack of difference noted in the"Lengthening Changes" column ofTable IV demonstrates that the areasmeasured were not affected in any wayby treatment. The inhibition of for-ward chin movement was not due to anylessening in growth of the mandible,Patient D L2-15-57 -2-14-58 --__ME-/MA-.? IA-2 I3MC-3 IC-3 f 4 Po-2 t4FIGURE 12Fig. 12. Tracings showing progress in oneheadgear patient. The exces8 downwardmovement accompanying the distal move-ment has resulted in the hingingopen ofthe mandible. Pogonion has moved 2 mmdistally from the original N-Po line. 246 Poulton October, 1959but a difference in direction of man-dibular growth. From present knowl-edge it seems doubtful that any treat-ment method could materially affectgrowth in length of the mandible.The inhibition of forward growth ofthe maxillary body was only .6 mmand, as was noted, the location of themeasurement point less certain thanother points used. Nevertheless, ob-servations in individual cases confirm-ed the trend, and an actual posteriormovement and slight downward tippingof the maxilla (the palatal plane) wasrecorded in several cases. This was thesame effect noted by Kleins in his re-port of cervical traction therapy.Headgear therapy is, therefore, ob-served to affect the position of both themandible and maxilla. The absolutesize of these changes is very smallwhen compared to changes in toothposition and they are not of any greatassistance in the clinical correction ofa Class I1 malocclusion. It is also ap-parent that in studies covering longerperiods of time and less active treat-ment mechanics, these changes wouldbe largely obscured by normal growth,if indeed they persisted at all.DISCUSSIONThe amount of distal tooth move-ment obtained in these cases was great-er than that reported with the cervicaltype of extraoral force appliance.Klein, using the maxillary outline forsuperposition, reported 1 mm averagedistal upper molar movement, butprobably would have recorded less ifa cranial registration were employed.However, the effect of headgear forceon the maxilla itself makes exact com-parison difficult. A small amount ofposterior movement was reported byEpstein in a few of his cases, andGraber and King found that in mostcases a maintenance of the normal for-ward molar movement was all thatcould be expected.Occipital headgear treatment ap-pears to be capable of substantial toothmovement in very young patients forWestz0 found an average of approx-imately 4 mm distal movement of up-per deciduous molars. This measure-ment includes an increase equal to theamount of forward growth at nasionbecause of the superposition method.It is impossible to determine exactlywhat effect the length of therapyperiod or the degree of patient cooper-ation had on the findings of most treat-ment evaluation studies. However, un-til other evidence is forthcoming, Iwould agree with the conclusion ofWest that distal movement of upperteeth is best accomplished with an oc-cipital headgear.The amount of anterior movementof the upper dentition recorded in theuntreated group points out the needfor an appliance capable of distal toothmovement. The dentition came for-ward about 1.3 mm in one year, whichwas more than the forward growth atnasion. Even so, it would take fiveyears to correct a moderate Class I1case with 6 mm of molar discrepancyusing an appliance capable of no morethan a holding action. The possibilityof tissue damage and loss of patientcooperation would make therapy ofthis length unacceptable to many.To gain a more thorough under-standing of the action of the occipitalheadgear, changes in occlusal planeangulation in relationship to other fa-cial changes werc examined. The planewas located on all the tracings by bi-secting molar and incisal cusp height.While the angle of the occlusal planeto the anterior cranial base did notchange in the untreated group, a meandownward tip of 2.8" (22.4,") wasnoted in the treatment group. Thescattergram in Fig. 13 shows that withan increase in occlusal plane tipping,a decrease in forward pogonion move-ment occurred; the correlation is high Vol. 29, No. 4 Headcap-_ .Therapy247OCCLUSAL 4PLANETIPPING 2 cb(degrees ) 0-I OU-2 -I 0 I 2HORIZONTAL POGONION MOVEMENT(rnrn.)Fig. 13. A scattergram showing the degreeof correlation between the horizontal move-ment of pogonion and tipping of the OC-clusal plane.(r = -.SS).This relationship was also observedby TovsteinZ1 in studying the effectsof intraoral Class I1 elastics on theocclusal plane. The elastic force pro-duced a downward tip averaging be-tween 4" and 7" and it could be in-ferred that this would be associatedwith a proportionately larger inhibi-tion of forward chin movement.Ricketts15 observed an increased in-clination of the mandible in casestreated with Class I1 elastics. Thissame type of unfavorable change wasnoted by King in cases treated withcervical anchorage and a full or partialedgewise appliance. Klein found thiseffect when treating cases with theKloehnZZ type of cervical anchorage.Downward tipping of the occlusaland mandibular planes is thereforecommon in most Class 11 correctionmechanics. The appliance therapy usedin "preparation of mandibular an-chorage" seems to be one means ofavoiding this tendency. Stoner, et a1.23,in studying a group of cases treated byTweed, found very little tipping actionand little inhibition of forward chinmovement. The use of Class I11elastics and very high pull headgearare undoubtedly instrumental in thisachievement. An important part of theprofile improvement associated withthis treatment is due to control of thedownward tipping of the occlusal andmandibular planes.APPLIANCE IMPROVEMENTClinical and cephalometric ob-servation has been continued in somepatients where longer therapy withthe occipital headgear was necessary.The vertical overbite was not decreas-ing and, in many cases, normal down-ward growth of the upper molars wasbeing restricted. In a few instances anactual open bite in the molar areawas created. Analysis of this behaviorof the teeth *made, the mechanics ofthe headgear clearer.Fig. 14(a) shows the appliance usedhere in relationship to dentofacialstructures as recorded in cephalometricfilms of patients wearing the headgear.The facebow is pulling at an anglesuperior to the occlusal plane, but adownward tipping of this plane was ob-served. The stippled area indicates thelocation of the maxillary dental rootsand alveolar process, and the letter"M" is the geometric center of thismass. With "My' considered as thecenter of resistance to the pull of thefacebow, the behavior of the teeth wasexactly as might be expected. Even theposition of the hook extending down-ward from the archwire tends to givean undesirable $orquing action.For those patients requiring addi-tional treatment, the headgear hasbeen modified as shown in Fig. 14(b).The hook has been moved forward, ex-tending upward from the archwire andthe direction of facebow pull has beenraised, which requires a different typeof head strap in most cases. On thebasis of these observations, distal pullon the upper dentition should be align-ed through "M", the center of themaxillary root mass, to avoid unde-sirable tipping movements. If openingof the bite is desired, the force should 248PoultonOctober, 1959Fig. 14. above. The relat,iondiip of dentofacial structures to the occipital headgear ap-pliance as recorded from lateral headGlms of patients wearing the appliance. Thestippled area indicates the roots and alveolar process of the maxinary dentition and "M"is the center of this mass. Arrows indicate the movement as a resultant of the appliedforce. Fig. 14, below. A higher line of force and point of attachment would be indicatedto correct excessive overbite and avoid downward tipping of the mandible. The amountof distal movement possible with this set-up has not been studied. Vol. 29, No. 4Headcap Therapy249be aligned forward and supenor to"MY.This type of "high-pull" headgearis currently coming into wide use inorthodontic practice, especially duringtherapy requiring reduction of incisoroverbite. The initial treatment resultsare demonstrating the effectiveness ofthe appliance in upper incisor in-trusion. Because a headgear applianceshows a wide variation in the relation-ship of the direction of pull to the teethin different patients, a "high-pull" orany other type of headgear should beselected according to the individualand to the malocclusion.Through the continued efforts of theorthodontic profession to objectivelyreport treatment results obtained withthe various appliance regimes, it willultimately be possible to appreciatethe therapeutic possibilities of everyavailable appliance. Only in this waycan the problems of each patient bemet with the most ideal, permanentand economical form of treatment.SUMMARYA group of 29 mixed dentition, Class11, Division 1 patients were treatedwith an occipital headgear and com-pared with a closely matched groupof untreated cases. Differences indentofacial changes between thegroups were analyzed at the end ofone year utilizing lateral cephalometricfilms.1.2.Molar relationships were correct-ed and incisor positions im-proved in nearly all the treatedcases, largely by a substantialdistal movement of the upperdentition. Most cases showed amarked distal position of themaxillary roots and uneruptedtooth buds.Comparison with the controlgroup revealed some inhibitionof forward maxillary growth and3.4.5..I .2.3.4.5.6.7.8.a slightly greater increase inlower face height. The dentitionin the control group moved for-ward more than the upper face.Regular daily wearing of theheadgear and the amount ofmandibular growth were shownto be the most important factorsin obtaining a prompt treatmentresponse.Analysis of the mechanics of theheadgear force used here sug-gested that changing the attach-ment and direction of pull in re-lation to the maxillary rootsmight improve the action of theappliance.From comparisons with toothmovement reported in otherstudies, the occipital headgearappears to be the most effectiveappliance for moving upperteeth posteriorly. Medical CentetUniv. of CaliforniaBIBLIOGRAPHYBrodie, A. G., Downs, W. B., Gold-stein, A., and Myer, E. CephalometricAppraisal of Orthodontic Results.Bngk Ortho., 8: Oct. 1938.Epstein, W. N. Analysis of Changesin Molar Relationships by Means ofExtraoral Anchorage in Treatment ofMalocclusion. Angle Ortho., 18: July,1948.Graber, T. M. Extraoral Force, Factsand Fallacies. Am. J. Ortho., 41(7) :July, 1955.King, Elbert W. Cervical Anchoragein Class I1 (1) Treatment, a Cephalo-iiietrio Appraisal. Angle Ortho., 27 :April, 1957.Erodie, A. G. Late Growth manges inthe Human Face. Angle Ortho., 23:April, 1953.Bjork, Arne. The Face in Profile.Svensk Tandlakare-Tidskrift, 40(55) :1947.Hein, Phillip L. An Evaluation ofCervical Traction on the Maxilla andthe Upper First Permanent Molar.Angle Ortho., 27: January, 1957.Ketterhagen, Donald. Taking a SecondLook at Headcap Treatment. AngleOrtho., 27: April, 1957. 250 PoultonOctober, 19599.10.11.12.13.14.15.16.Keith, A. and Campion, G. A Con-tribution to the Mechanism of Growthof Cho Human Face. Dental Record42(2): 1922.De Coster, L. Une Nouvelle Ligne deReference pour L'analyses des Teleradiographies Sagittales en Orthodon-tie. Revue de Stomatologie, ll(12):1951.Bjork, Arne. Cranial Base Develop-ment. Am. J. Ortho., 41: March, 1955.Lande, M. 5. Growth Behavior ofHuman Facial Bony Profile as Re-vealed by Serial Cephalometria Roent-genology. Angle Ortho., 22 : April,1952.Steiner, C. C. Cephalometries for Youand Me. Am. J. Ortho., 39: October,1953.Broadbent, B. H. A New X-ray Tech-nique and its Application to Ortho-dontia. Angle Ortho., 1: 45-66, 1931.Bicketts, R. M. Facial and DentureChanges During Orthodontic Treatmentas Analyzed from the Temuoroman-dibular "Joint. Am. J. Ortho., 41:March, 1955.Blair, E. S. A Cephalometric Roent-17.18.19.20.21.38.23.genographio Appraisal of SkeletalMorphologg. Angle Ortho., 24: April,1954.Wylie, W. L. The Assessment of An-teroposterior Dysplasia. Angle Ortho.,17: Juh. 1947."IGraber, T. M. Workshop on Roent-genographia Cephalometrics, p. 279,March, 1957.Higley, L: B. Workshop on Roent-genographia Cephalomtrics, pp. 279-280, March, 1957.West, E. E. Afialysis of Early Class11. Division 1 Treatment. Am. J.Ortho., 43: October, 1957.Tovstein, B. C. Behavior of the Oc-clusal Plane and Related Structures inthe Treatment of Glass I1 Maloc-clusion. Angle Ortho., 25 : October,1955.Kloehn, S. Orthodontics - Force orPersuasion. Angle Ortho., 23 : JanuarJ,1953.Stoner, M. M. et al. A CephalometricEvaluation of 57 Consecutive CasesTreated by Tweed. Angle Ortho., 26:April, 1956.The AngleOrthodontistA magazine establishedby the co-wor$ersof EdDard H. Angle,in his memory . . .Editor: Arthur B. Lewis.Business Manager: Silas J. Kldn.Associate Editors: Allan C. Brodie.Morse R. Newcomb, Harold J. Noyes,Robert H. W. Strang, Wendell L. Wylie.Vol. XXIX, No. 4 October, 1959