Cephalometric Analysis Of TreatmentWith Cervical Anchorage*WILLIAM A. BLUEHER, D.D.S.Albuquerque, N. M.The primary purpose of this studywas to determine the facial skeletalchanges which occur during treatmentwith the full edgewise appliance pluscervical traction. The cases recordedwere classified as Class 11, Division 1and Class I with Class I1 tendencies,all without extractions. The neckbandappliance was the prime motivatingfactor for redyction of the Class I1relationship or tendency.Much of the credit for the wide-spread revival of extraoral anchorageis due Kloehn. His work, as first report-ed at the meeting of the Mid-westernComponent of the Edward AngleSociety of Orthodontia, 1947, mademembers of the profession aware of thevalue of cervical traction in a privatepractice. Kloehn stressed the guidanceof growth and the conservation ofmandibular anchorage made possiblewith the cervical gear. The cases dis-cussed in this paper were treated withthese fundamental aspects in mind.Thirty-four individuals are repre-sented : seventeen boys and seventeengirls. Six of the boys and six of the girlshad two periods of treatment, a pre-liminary period with the neckband ap-pliance only, and a second period witha full edgewise appliance added. Themean starting age for the preliminaryperiod was ten years while the meantreatment time was eleven months. Thesecond period of treatment for thechildren in this group averaged fifteenmonths; the total mean time for the*Presented before the Mid-western Com-ponent of the Angle Society, Indianapolis,January, 1958.two periods combined was twenty-sevenmonths.For the eleven boys and eleven girlswho were treated in one period, themean starting age was thirteen years,and the mean treatment time eighteenmonths.Tracings of before and after treat-ment lateral head x-rays were made.All angular values were read with astandard protractor and lineal measure-ments were determined with millimeterrule. The Frankfort plane of eachoriginal tracing was transferred to thesecond by superimposition of the SNplane registered at S.The following angular measurementswere made: SNA, SNB, SNPo, NAPo,NSGn, the angle of the palatal planeto a perpendicular projected from S-N,and the mandibular plane angle ac-cording to Downs.The linear measurements were: SAand SB.Perpendiculars were projected to theFrankfort plane from points S, A, andB and the distances from S to A andB measured in millimeters. The pointS was selected as a base from whichto measure because it has been estab-lished as one of the most stable pointsof reference in the head.Class I cases demonstrating a ClassI1 tendency were included with theClass 11, Division 1 cases in this studybecause therapy was identical. Further-more, Landes showed the same generaltendencies in growth behavior regard-less of type. Silversteinlo concludedthat in his sample there was no sig-nificant difference in growth trends be-45 46 Blueher January, 1959tween untreated Class I1 cases and un-treated normals.ANTERIOR MAXILLARY ALVEOLAR PROCESSPj euious FindingsBrodie' in his study of growthchanges from the eighth to the seven-teenth years showed that the conforma-tion of the anterior surfaces of the al-veolar process of maxilla and mandiblechange little or "drop back".Lande8 evinced relative stability ofthe anterior maxillary area in untreatedcases. He went further to confirmBrodie's observation that the alveolargrowth did not keep pace with thegrowth of its skeletal base in a hori-zontal. direction. Both substantiated thefindings in this regard of earlierworkers.Ricketts!' in an unpublished study ofuntreated Class 11, Division 1 cases dis-covered very slight if any change inpoint: A.Carlson' in an unpublished thesisctudying ten boys and ten girls withcxcellent occlusions showed a slight in-crease in SNA from ages eight to seven-teen, the increase being greater in malesthan females. Clement?, also in an un-published thesis, measuring twenty-onemales and fifteen females with goodto excellent occlusions raw a significantincrease in SNA in males between eightto twelve years and in girls betweenten and twelve.Silverstein'" found that SNA tendedto decrease in males with treatmentbut not in females. Graber4 spoke oftreatment cases in which maxillary al-veolar growth was apparently held backby extraoral appliances.Stoner", and co-workers using alinear measurement demonstrated a re-duction of point A in cases treated byTweed. King' showed a similar reduc-tion with cervical traction. Klein6 aftermeasuring SNA writes of an averageretraction of 1.3' in cases treated withcervical anchorage. Eight,of his twenty-four cases yielded no change.Present FindingsIn the boys in this study the great-est change in SNA was reduction of4,.5', the least .5", and the mean 1.86'.In the gir:s the largest decreare was 7',the least .5", and the mean 2.39". Itmust be noted that the average re-duction in the girls without the unusualhigh of 7" would have been 1.96',which is still higher than the meanfor the boys. There was a reduction infifteen of the seventeen boys and four-teen of the seventeen girls.Only one individual, a boy, in thethirty-four total cases showed an in-crease in SNA (2.5'). The before andafter readings remained the same forone boy and three girls. In summationthere was an SNA reduction in twenty-nine of thirty-four cases; the angle re-mained the same in four cases, and in-crrasPd in one.Lnrnr Measurements of Point AThe SA distance along Frankfortplane decreased in eight of the seven-teen boys, twelve of the seventeen girls.Thc greatest decrease in the boys was3 nim., the least .5 min., the mean 1.5mm. The largest decrease in girls was4 mm., the smallest .5 mm., the mean1.66 mm.The distance from S to A increasedin nine boys and in only three girls.The high increase in the boys was 4.5mm., the low .5 mm., the mean 2.38mm. The high in the girls was 4 mm.,the low 1.5 mm., and the mean 2.66mm. Two of the girls remained thesame.DISCUSSIONThere appears to be no correlationbetween a decfease of the angle SNAand a decrease in the S to A linearmeasurement. Vol. 29, No. 1 Treatment Analysis 47Our findings bear out those of theother workers quoted who have foundthat treatment does influence the angleSNA and the point A. In this instance,we have shown that the forward growthof the maxillary anterior alveolarprocess was restricted in full edgewiseappliance cases using the neckband ap-pliance as the restraining force.It would appear also from ourmeasurements that this alveolar processmay be more readily held back withcervical traction in girls than in boys.Or, it may be said that the forwardgrowth tendency in boys is greater thanin girls; that the resistive force of theneckband appliance has more to with-stand or overcome in the male.This is a different concept from thatexpressed by Silverstein who found atreatment decrease in SNA in males butnone in females. It is the opposite idea,also, from that of King who foundthe greatest change in point A in males.Silverstein's report included seventy-four Class I1 cases (forty more thanthis sample) in which it is presumedthe chief reducing agents were ClassI1 elastics. King reported fifty Class 11,Division 1 cases (sixteen more thanthis paper), both extraction and non-extraction with a greater age range, andsome of his cases did not have fulledgewise appliances in addition to theneckband appliance.On the basis of the findings in thesmaller sample reported here and withthe conclusions of Carlson and Clementsin mind (that SNA increases more ingood occlusion males than females) Isubmit the opinion that:1. Cervical traction may retract orhold back forward change of the max-illary anterior alveolar process more innonextraction girls than in nonextrac-tion boys because females do not haveas much forward growth force.2. Some of the greater forwardgrowth force potential in boys may ex-press itself in spite of the restraint ofcervical traction.3. If concepts 1 and 2 should betrue, then boys, ideally, ought to wearthe neckband appliance twenty-fourhours a day, whereas the girls, havingless growth to hold back, should needto wear the appliance only twelve tofourteen hours daily. This might be trueif the end result of treatment was con-cerned only with reduction of point A.However, the comparatively greaterforward growth at other facial pointscompensates for this relative difficultyin restraining point A in the male.MANDIBULAR ANTERIOR ALVEOLARPROCESSPwvious FindingsLande found no significant change inpoint B from seven to twelve years,but a mean forward movement of2.2 mm. from twelve to eighteenyears. SNB was not affected by treat-ment Silverstein observed, while Stonerand his co-workers found a mean for-ward movement of .08 mm. in the fifty-seven consecutively treated Tweedcases.Carlson found an increase in SNBfrom eight to seventeen years. This in-crease was greater than the SNA in-crease and more in males than females.Clements reported an increase in SNBin both males and females.Present FindingsThe angle SNB increased in nineboys, decreased in four and remainedthe same in four. It increased in eightgirls, decreased in seven and remainedthe same in two.In boys the high increase was 2",the low lo, and the mean 1.27"; girlshad a high increase of 2.5", a low of.5", and a mean of 1.5". The greatestmale decrease was I", the lowest .5",the mean .87", while the greatest fe-male decrease was 1.5", the lowest .5",and the mean .85". 48 Blueha January, 1959Linear Distance of SBThe SB distance increased in thirteenboys, decreased in three and remainedthe same in one. It increased in tengirls, decreased in five, remained thesame in two.The high increase in the boys was7 mm., the low .5 mm. and the mean3.38 mm. with a high increase in thegirls of 6 mm., a low 1 mm. and amean 2.65 mm.Boys' greatest decrease was 2.5 mm.,the low .5 mm. and the mean 1.33mm. The greatest decrease in the girlswas 4.5 mm., the low .5 mm., the mean1.4 mm.DISCUSSIONThe measurements of SNB changewith this treatment would indicate thatthis angle is just as likely to either de-crease or stay the same in both sexes,as it is to increase. Seventeen of thetotal cases decreased or stayed identicalwhile seventeen increased. The bigdiEerence was tile fact that ths meanincrease was greater than the meandecrease.With regard to the SB linear distancethere is a decided statistical advantageon the side of the increase. Twenty-three of the total showed an increase,while eleven decreased or stayed thesame. The increase was greater in theboys than in the girls. The mean de-crease was similar in the two sexes.A comparison of the results of theangular and lineal measurements relatedto point B indicates that much of theforward growth of the mandibularanterior alveolar process may be mask-ed in the angular measurements by theforward growth of point N. The SBmeasurements show that B moves for-ward predominantly in both sexes butmore in boys than girls. This wouldtend to confirm the findings of Lande,Stoner et. al., Carlson, and Clements.It would appear likely that point Bwas affected very little, if any, by treat-ment as Silverstein noted. However,where there was a decrease in the SBdistance or where it remained the same,the bite opening effects of treatmentmay have had some influence. Thiswould tend to corroborate King whenhe said that such bite opening apparent-ly occurred in individuals who grewlittle or none at all, and that this open-ing remlted in a downward and back-ward displacement of the mandible.SNPQPrevious FindingsLande found that there was an in-crease in mandibular prognathismgenerally occurring beyond seven yearsof age.Brodie in measuring SNGn showeda predominantly forward movement ofthe chin point of three to six degrees.Four of his nineteen cases remainedthe same.An increase in SNPo in untreatedmales and females was noted by Silver-stein. in the anaiysis of traaierl S.PF.~She concluded that the forward move-ment of pogonion was inhibited inboth sexes to the extent that the ex-pected growth potential was net at-,tained.Stoner and his group in their linearmeasurements of point Po found that itmoved forward more than six timesfarther than point B; King concludedthat forward growth of pogonion wasdisappointing in all his treatmentgroups except nonextraction males.Present FindingsThe angle SNPo increased in ten bavs,decreased in three and remained thesame in four. It increased in nine girls,decreased in five, and stayed the samein three. Nineteen of the entire grouphad an increase, eight had a decrease,and seven remained the same.The boys showed a high increase of3", a low of lo, and a mean of 1.65'.The girls evidenced a high increase Vol. 29, No. 1 Treatmentof 3.5", a low of .5", and a mean of1.55".The three boys who showed a de-crease were identical with l" each,while the greatest decrease in the girlswas lo, the least .5" and the mean .8".DISCUSSIONIt is regrettable that the plan forthis paper did not include a linealmeasurement of SPo. The interestingfindings brought out by comparison ofthe angular and linear measurements ofpoints A and B dictate inclusion of SPoin a contemplated revision of this work.The interesting factor, however, inthe measurements of SNPo is the simi-larity of behavior in the two sexes. Notonly were the numbers of boys andgirls in each category nearly the same,but also, the high, low, and meanmeasurements were practically identical.Furthermore, the changes occurringin SNPo were much like those of SNB,as to numbers of individuals in eachcategory and all measurements. Thereseemed to be a slightly greater quantityof increase in point Po than B, but inthe instance of decrease the quantitywas equable.The fact that in the decrease casesthe angles SNB and SNPo were reducedsimilarly could lend further strength toKing's expression of the bite-openingeffects of treatment in poor growthcases. This may also be further evidenceto confirm Silverstein's conclusion thatforward growth of pogonion can be in-hibited by treatment.NAP0Previous FindingsOne of Lande's chief conclusions wasthat the convexity of the face nearly al-ways decreased. It will be recalled thatthis was in a study of thirty-four cases,ten of which had Class I1 denturerelationships.Carlson noted that the facial profilebecame less convex with growth andAnalysis 49that this straightening was greater inmales than females. He found that thisdecreased convexity was associatedmore with an increase in face heightthan a change in the sagittal relationof the jaws.In this regard King mentioned thathis treatment cases exhibited downwardgrowth in excess of forward growth.Klein, in his twenty-four cases treat-ed with cervical traction, noted a rangeof decrease in the angle of convexityof 0" to -7" with a mean reduction of2.8". He mentioned the significance ofthis change since the majority of hiscases evidenced an opening of the Yaxis; and further, the chin appearedless prominent in some cases as a resultof bite opening or growth.Presmt FindingsOf the entire thirty-four cases,thirty-three showed a decrease in con-vexity; and one remaining case - aboy - remained the same. Therefore,sixteen boys had a decrease as did allseventeen girls.The greatest decrease in the boys was9.5", the low lo, and the mean 4.93".The largest decrease in the girls was16", the least .5", and the mean 5.08".Eliminating the unusual high of 16"in the girls, the high would have been9": and the mean 4.37".The convexity reductions of the sixboys and six girls who had two periodsof treatment ( 1st-neckband appli-ances, 2nd-neckband appliances plusfull edgewise appliances) were thenieparated from the group. It was foundthat the high reduction for the six boyswas 9.5" the low 2.5", the mean 5.66";for the six girls the greatest reductionwas 7", the low 1.5", and the mean4.66".The ten boys showing reduction andhaving just one period of treatmentshowed a high decrease of 8", a low oflo, and a mean of 4.5".The ten girls (still excluding the un- 50 Blueher January, 1959usual high) treated in one period hada high decrease of 9", a low of 1.5",and a mean of 4.35".DISCUSSIONThe above mentioned ten boys and tengirls had a starting age range of elevenyears six months to fifteen years fourmonths with a mean starting age ofthirteen years. The treatment timeranged from fourteen to twenty-twomonths with a mean of eighteenmonths.Klein's sample of twenty-four young-sters was started from seven yearsseven months to ten years two monthswith a mean starting age of eightyears six months. The treatment timeranged from six to thirty-three monthswith a mean of seventeen months.These cases were treated with neckbandappliances together with flat acrylicbite planes in some cases.The mean reduction in our twentyfull appliance plus neckband casescase had been included the mean wouldhave become 4.19"). Klein's neckbandappliance cases, at an earlier age butwith almost the same average treat-ment time, had a mean convexity de-crease of 2.8".There would seem to be a significantdifference in the convexity change atthe two ages. In all probability the addi-tion of the full edgewise appliance didnot account for this difference, butrather growth variance in the two agegroups was chiefly responsible.Following the findings of Carlson andKing it may well be that a greater in-crease in face height in the older groupwas a major contributing factor.In consideration of the entire groupof thirty-four children, less the boy whohad no change and the girl who hadthe unusually high change, the similar-ity in measurements is noteworthy. Thehigh, low, the mean readings in thetwo sexes were very close with those ofwrs 4.42" (if the nne zern changethe girls being slightly less in eachrespect.Silverstein found that there probablywere individual differences in growthtrends between the two sexes. He be-lieved, however, that these differenceswere probably masked by the greatvariation within each sex.Most of the workers previously re-ferred to did find that the quantitativechange in a great number of measure-ments in the two sexes showed thesame trend, with the boys generallygreater than the girls.NSGNPrevious FindingsFrom his sample Lande's measure-ments showed that NSGn evidencedvery little change from seven to seven-teen years.Rrodie concluded that this angle wasquite stable from eight to seventeen.He found no change in it in eleven ofnineteen cases. The angle increasedaround 2" in seven cases axid decie-edin only one.Klein measured the Y axis from theBolton plane and found that in hiscervical traction cases it opened anaverage of 1" with a range from a re-duction of 1 " to an increase of 3".Present FindingsIn a total of twenty-two of the thirty-four cases the angle NSGn opened. Inthe eleven boys showing an increase thehigh change was 4", the low .5", andthe mean 1.86".In the eleven girls the high was 2.5",the low .5", the mean 1.5".One boy had a decrease of 1". Twogirls decreased 1" and 2" respectively.Five boys and four girls remained thesame.To recapitulate: in twenty-two casesNSGn increased; in three cases it de-creased, and in nine cases it stayed thesame. Vol. 29, No. 1 Treatment Analysis 51DISCUSSIONIn the face of this evidence, therecan be little doubt that treatment withcervical anchorage does tend to causea bite opening. It is probable also thatthe addition of a full edgewise appli-ance and treatment between eleven andfifteen years produced a greater degreeof opening.There is no apparent relationshipbetween length of treatment and degreeof NSGn increase. Some of the casestreated the longest showed less thanaverage opening. One boy and one girlin this group stayed the same, and onegirl decreased. Those who grow wellseem to open the least, again tendingto verify the findings of King.MANDIBULAR PLANEPre uious FindingsLande found a decrease in the in-clination of the mandibular lowerborder associated with the increase inmandibular prognathism. Over half ofBrodie's cases demonstrated no notablechange in the mandibular border.Where there was a change, it was a de-crease.Silverstein found a decrease in themandibular plane angle with age. Hefound also that treatment inhibited thisdecrease and reversed the normalgrowth tendency in the female, causingthe angle to increase.King's cases showed an increase inboth sexes but this was not as great asthat shown by Tovstein in cases treatedwith Clars I1 elastics.Present FindingsIn six of the boys the mandibularplane angle increased from 1" to 5"with a mean of 2.33"; in eight boys theangle decreased from 1" to 4" with amean of 2.12"; and in the remainingthree the angle was unchanged.Ten of the girIs showed an increaseof .5" to 3" with a mean of 1.35"; Fivegirls showed a decrease of 1" each, andin two girls there was no change.Therefore, sixteen of the thirty-fourcaces evidenced an increase in themandibular plane angle while thirteenhad a decrease, and five remained thesame.DISCUSSIONIt would appear that about one-halfthe cases treated with full edgewiseappliances plus the neckband appliancestend to show an increase in themandibular plane angle.The mean increase in the mandibularplane inclination was greater in theboys than in the girls. Likewise, whenthe mandibular plane decreased, it didso greater in the boys than in the girls.But the angle in the majority of boyseither decreased or remained the samewhereas, in the majority of girls it in-creased. Can the basis for this differ-ence be laid again at the feet of ourpatron saint, growth?Can the finding of Lande, that thedecrease of the mandibular lowerborder was associated with the increasein mandibular prognathism, be turnedaround to apply here? Can it be saidthat because the girls tend to lessmandibular prognathism, that theirmandibular planes have less tendencyto decrease? And that, therefore, thisplane in girls is more easily influencedto increase by treatment?PALATAL PLANEPrevious FindingsRrodie noted a definite tendency forthe hard palate or nasal floor to re-main stable over the entire growthrange. In those cases where there wasa change, the anterior end droppedmore than the posterior. In terms ofthis paper, the described change wasan increase in the palatal plane angle.In his treatment cases Klein foundthat the palatal plane predominantly 52BlueherJanuary, 1959dropped downward anteriorly; in onlyfour cases did the plane remain thesame; in no case was there a decreaseof the angle or a greater droppingposteriorly rather than anteriorly.Present FindingsTwenty-five of the thirty-four casesdemonstrated an increase in the palatalplane angle; six showed a decrease;three remained the same.Twelve boys had an increase of 1"to 5" with a mean of 1.95". Three ofthe boys showed a decrease of 1" to1.5" with a mean of 1.16". Two boysremained unchanged.The angle increased in thirteen girlsranging from .5" to 3". The mean in-crease was 1.76". It decreased in threegirls 1" each. One girl remained thesame.DISCUSSIONBefore discussing the findings, itwould be well to point out that delinea-tion of the posterior nasal spine in theheadplate of a pre-adolescent youngstercan be difficult. This point can be ob-scured by the shadow of the eruptingsecond molars. It would appear thaterror is definitely possible, but it maybe that this error is duplicated fromtracing to tracing thus minimizing itssignificance.It seemed, though, that a trend wasapparent in treatment cases. Thepalatal plane angle increased in themajority of Klein's cases and so alsodid it here. Perhaps, as Klein specu-lated, cervical traction can alter thebasic maxillary structure.The small decrease in the angle insix cases is not understandable on thebasis of previous findings and may bedue to error in tracing.SUMMARYIn Class 11, Division 1 and Class I1tendency cases treated with full edge-wise appliances plus neckband appli-ances as auxiliaries the following ob-servations were made :1. The angles SNA and NAP0 weregenerally reduced.2. The SA distance was reduced inthe majority of cases. This reductionoccurred more often in the female thanin the male. In the boys A moved for-ward as often as backward. The milli-meter change in forward movementwas greater than that which occurredin backward movement.3. SNB behaved similarly in bothsexes. It tended to stay the same ordecrease, as often as it increased. Thedecreases when registered were smallerthan the increases and may have beeninfluenced by bite opening.4. The SNPo measurements werestrikingly like those of SNB. The onlyreal difference was that the degree ofincrease of SNPo was slightly greaterthan that of SNB.5. The SB distance increased in themajority of both boys and girls. Theincrea!e in the boys was greater thanthat in the girls, numerically andquantitatively.6. The differences between angularand linear measurements of points Aand B respectively indicate a maskingof true events in the recordings ofangles. It should be. remembered thatSNA, SNB, and NAP0 are influencedby growth activity at points other thanA and B.7. NSGn increased in the majority ofcases, indicating the bite-opening pro-pensities of the appliances.8. The mandibular plane either de-creased or stayed the same in most ofthe boys whereas it tended to increasein the majority of girls. This may beanother indication of greater growthforces in the male than in the female.9. The palatal plane increased in themajority of both boys and girls. If thepossibility of error in tracing could bediscounted, this increase would be in-dicative of a tendency for the neckband Vol. 29, No. 1Treatment Analysis53appliance to change the palatal planein a natural direction.The recognized variables in a studyof this type primarily concern thepatient. Not only are there differencesbetween the sexes, but also, there arewide individual variations: of growthactivity related to age, of tissue re-sponses to orthodontic prezsures, andof individual patient cooperation in fol-lowing instructions. The fact that themajority of patients respond in one wayin one area of measurement does notprognosticate like reaction in any otherindividual.This paper is presented with fullrecognition of the above facts, as arecord of changes in some patients toone form of clinical management.Medical Art SquareBIBLIOGRAPHY1. Brdie, A. G.: Late Growth Changes inthe Human Face. Angle Ortho., 23 : 146-167, 1953.2. Carlson, D. H.: A Serial CephalometricRadiographic Study of the Anteropos-terior Relation of the Maxilla andMandible in Individuals with ExcellentOcclusion of the Teeth. Master's Tlirsis,Worthwestern University, 19.75.3. Clements, B. S.: A Serial Ccphdoiiietric.Analysis of Growth of the Maxilla andEruption of Certain Maxillary `Teeth.Mlasler's Thesis, University of Wadling-ton, 1956.4. Graber, T. M.: Extraornl Force-Fwtsand Fallacies. Am. J. Ortho., 41: 490-505, 1955.5. King, E. W.: Cervical Anchorage inClass 11, Division 1 Treatment, ACephalometric Appra ;sal. Angle Ortho.,6. Klein, P. L. : An Evaluntiou of CervicalTraction on the Maxilln and the UpperFirst Permanent Molar. Angle Ortho.,7. Kloehn, S. J. : Guiding Alveolar Growthand Eruption of Teekh to Reduce Treat-ment Time and Produce a More Bal-anced Denture and Face. Angle 01 tho.,8. Lande, M. J.: Growth Behavior of theHuman Bony Facial Profile as Revealedby Serial Cephalometric Roentgenology.Angle Ortho., 22: 78-90, 1952.9. Ricketts, R. M.: Unpublished study.1957.10. Silverstein, A.: Changes in the Bong Facial Profile Coincident with Treatmentof Class 11, Division 1 (Angle) Malor-clusion. Angle Ortho., 24: 814-237, 1954.11. Stoner, M. M. et. al.: A CephalometricEvaluation of Fifty-seven Consecutive Cases Treated by Dr. Charles H. Taeed.Angle Ortho., 26: 68-98, 1966.27: 98-103, 1957.27: 61-68, 1957.17: 10-33, 1947.