Recognition And InterceDtion Of Aberrant1Canine Eruption *MORSE K. NEWCOMB, D.D.S.Cleveland, Ohio"Eruption" of a tooth has twomeanings. Although conimoiily usedto denote appearance in the mouth,each tooth traverses, normally, a welldefined path through the maxilla ormandible. This double meaning oftooth eruption has been emphasized byBroadbent3,* by Noyes, Schour andNoyes8 and by others. Aberrant erup-tion of thc canine tooth means de-viation from its usual path duringmigration from its site of orgin atabout the end of the first year of life.This site in the maxilla is immediate-ly above the root ends of the deciduousfirst m01ar.~ As pointed out by Dew-elG, the maxillary canine's path is un-usually lengthy in time consumed aswcll as in distance traversed for as-sumption of its placc in thc dentalarch.Numerous references in our litera-ture testify to orthodontic interest inthis tooth. Blum5 has stated theincidence of canine impaction is sec-ond only to that of the mandibularthird molar and as recently as 1952-53 we find this statement: "The gen-eral practitioner should x-ray the en-tire mouth routinely and be suspiciouswhen the deciduous teeth are retainedafter the age of twelve or where per-manent teeth are missing".8This characteristic preoccupationwith impacted canines implies thatsuch developmental problems can notbe prevented and partakes of the ig-nominy of locking the barn door after* Presented at the January, 1959 meeting ofthe Mid-Western Component, E. H. AngleSociety of Orthodontia, Cliieago.the horses have entered the cornpatch. Recognition of potential ca-nine impactions was implicit in thefirst reference to "the ugly ducklingstages of normal development" in1930.1 Here was presented a chartingof normal relationships; the roent-genographic technique had beendescribed earlier but published sub-sequently.' Broadbent also empha-sized the role of the general den-tist in this problem during the Illi-nois Telephone Extension Program of1951-52 and illustrated these uglyduckling stages in the manual issued tosubscribers.4It is, then, niy hope to interest youin the routine serial usc of both lateraland posteroanterior head films, priorto appliance intervcntion, as ameans of recognizing these potentiali-ties and intercepting thcm by dentalsurgery. I realize that they can behandled by the use of dental x-rays*although this usually involves refer-ring the patient. I also realize thatone can sometimes recognize symptomsof cuspid aberrancies prior to clinicaleruption.Figure 1 is the frontal view of theplaster casts of a girl nine and one-half years old. Neither dental norcephalometric x-rays are needed inthis instance to alert the orthodontistto the acutely anterior location of themaxillary canines.At the opposite end of the scale, forcontrast, the orthodontist may be con-fronted with the problem pictured inFigure 2. These plaster reproductionsof a boy of almost thirteen years showa total lack of the labial alveolar bulge161 I62Newcomb July, 1959Fig. 1 above, Fig. 2, bclon.of the niaxillary canines seen in thefirst illustration. Obviously, there is anacute retardation of this patient's den-tal maturation and the relationshipsof the maxillary cuspids need investi-gation. Roentgenographic examina-tion revealed, among other problems,potential palatal impaction of theseteeth; this evidence will be demon-strated later.In line with Todd's dictum that torecognize the abnormal we must firstknow the normal, I quote Broadbent'sremarks about the "ugly duckling"stages of the developing dentition."The shedding of the baby incisorsand the eruption of their successorsmarks the advent of the one verystriking example of these ugly duck-ling stages. This stage when viewedfrom the frontal aspect - - - - -, afterthe age of six and one-half years,finds the upper centrals erupting in arelatively short period of time andusually with a separation at the mid-line. The upper permanent lateralsfollow and the centrals move togetherinto approximal contact. The growthin lateral dimension of the support-ing structures, especially the area atthe level just below the floor of thenose where the upper cuspids are de-veloping, is relatively slower, whichforces the lateral incisors into a fan-shaped pattern that becomes morcpronounced until the time whenthere has becn sufficient gain in lat-eral growth in the apical base. Coin-cident with the eruption of the cuspidsthis lateral dimension increases to per-mit the morc erect position of theincisors".3When one examines a patient in hisniiddle teem who has retained a de-ciduous cuspid, it means that some-one has disregarded the devclopingdental patterns just described. Thenext illustration, Fig. 3, depicts thetracing of the frontal x-ray of a boy(W.T.) of almost fifteen years wherethis has occurred. This clearly showsthe succedaneous tooth to be in anunfavorablc position relative to theW. 1. 14-11Fig. 3 Vol. 29. No. 3Canine EruptionI63Fig. 4central and lateral incisors. Imme-diate removal of the deciduous toothwas advised together with generousremoval of alveolar bone7 to en-courage clinical eruption of the per-manent canine. Three months aftersurgical intervention the cuspid wasvisible clinically although it was ling-ually positioned. The patient is nowunder treatment.This problem could have been a-voided with the supervision obtainedby patient D. P., Fig. 4. This boy wasfirst seen and clinical records made atthe age of ten years and two months.The positions of the permanent maxil-lary cuspids were considered only apotential problem, relative to his re-tarded dental development, and asecond x-ray examination was advisedat about the eleventh birthday. Theillustration on the right was tracedfrom the P.-A. film made at that ageand indicates further medial tippingof the permanent maxillary canines.Immediate extraction of both pri-mary cuspids and removal of alveolarbone was suggested and followed. Thispatient was examined a year laterwhen it was seen that the left cus-pid was visible in the mouth. Theright one was not in sight but wasdefinitely labial as shown by the bulgecreated between the first premolar andlateral incisor on that side. Througha combination of circumstances thispatient was not seen again for moreFig. 5 1 64NewcombJuly, 1959Pig. 6than two ycars at which time theplaster records were made whichdemonstrate a favorable terminationfor thc teeth in question Fig. 5.It should be noted that the lateralx-ray film provides no guide to thescpotential impactions. Figure 6 showstracings of the complementary lat-eral and posteroanterior x-ray filmsoriented in the Frankfort Plane. Thisis the roentgenographic evidence ofthe patient whose plaster casts, whichwere seen in Figure 2, gave no clinicalsign of the maxillary canine teeth. Itis only in the P.-A. image that onecan judge the mediolateral positionsof the permanent cuspids. In this boyof twelve years and nine months (toprow) immediate extraction of the de-ciduous upper canines was orderedtogether with generous removal of al-vcolar bonc. A year later, elevenmonths aftcr thc surgcry, the tracingof thc second lateral film indicates on-ly additional root formation and fur-ther dcscent of the permanent cuspids.In the tracing of the second P.-A. film,however it is obvious that both up-per cuspids have reacted favorably:they have moved laterally, are moreupright, and thus give assurance thatthey will eventually assume correctpositions in the dental arch.A similar problem is shown inFigure 7. In this girl of just pasteight ycars both upper lateral incisorshad appeared but the lower deciduouslaterals were still in place. The up-per deciduous right central also re-mained and had apparently servedto deflect the upper permanent cen-trals. The deciduous upper central Vol. 29, No. 3 Canine Eruption 165Fig. 7 a.bove, Fig. 8 below.was exfoliated shortly after this firstrecord and a second set of clinicalrecords was obtained a year later.The tracing of this P.-A. x-ray, takenat nine years and one month, showsimproved positions of the eight in-cisors but medial tipping of the fourpermanent canine teeth. As alreadyseen in the "ugly duckling" patternat the nine-year level, this normallyis the case but it provides a stormwarning for the orthodontist whichshould not be ignored. A third setof clinical records taken fourteenmonths later, at the age of ten yearsand three months, gave further sub-stance to the warning and x-rayswere subsequently made at six-monthintervals. These also confirmed a sig-nificant and progressive retardationin dental maturation. The tracingof the P.-A. film at the twelve year Newcomb July, 1959166vFig. 9Fig. 10ancl onc month stagc, conibincd withthc dental x-rays, lctl mc to ordcrextraction of thc rcinaining tlircc dc-ciduous caninc tccth. Finally, at thcagc of thirtccn and a half, thc fourpcrmancnt canincs wcrc visiblc clini-cally and approaching satisfactorypositions with the exception of thc ro-tation of that on the lowcr lcft sidc.Figurc 8 shows frontal vicws of theplaster casts at the ages of eight/one,nine/one and thirteen/six.In this instance the cuspids mighthave appeared without the roentgeno-graphic supervision and the deciduouscxtractions. It shoultl bc adtlcrl thatbctween thc age of nine years anclonc month and that of tcn ycars andthrcc months, thcrc was six monthsof trcatnicnt and a short rctcntionpcriocl.It is oftcn difficult to dclincatc thccxtcnt of root absorption on the dc-ciduous canines in eithcr the latcralor posteroanterior film. In thc in-stance of C.K., a girl of eleven yearsand five months, it was apparentfrom the P.-A. film that the upperleft permanent canine represented apotential impaction: Fig. 9. The den- Vol. 29, No. 3 Canine Eruption 167w 0. 111Fig.tal x-rays confirmctl that the decid-uous upper left cuspid was unfav-orably influencing its successor andits extraction was ordcrcd. The pa-tient was cxamincd at six monthintervals until both cuspids were wellpositioned two years later, Fig. 10.Treatment was then started withoutthe tedious effort to position the sametooth required in the instance of pa-tient w. Q., whose frontal tracings areseen in Figure 11.These show that this program ofsupervision is not infallible. The firstx-rays were made at the age of nineyears and one month. In view of thepatient's acutely retarded developmentthe positions of the permanent canineswere not considered to be a poten-tial hazard. Two years later, how-ever, they were viewed with sus-picion and, when compared with theirmore unfavorable positions at twelveyears and seven months, the upperdeciduous canines were seen torequire extraction. This patient'strcatnicnt, for a scvcrc Class 11, Div.I nialocclusion, was startctl at four-teen and one-half ycars, after the upper right cuspid had appeared. Whenhe was almost fifteen and a half, theP.-A. x-ray showed impaction of theupper left cuspid. It was surgically ex-posed and moved to its proper posi-tion during the last half of an undulylong period of active treatment cover-ing more than two years. The increas-ingly oblique positions of the uppercanines in the x-rays prior to treat-ment should have constituted sufficientwarning to require free alveolar boneremoval rather than simple removalof the deciduous tooth, thus probablyavoiding the impaction.With few exceptions in my exper-ience, potential impaction of perma-nent canine teeth is seen in patientsexhibiting moderate to severe retard-ation of dental maturation. By thatI mean a slow rate of permanent toothformation as well as retarded exfol-iation of the deciduous teeth. It would I68 Newcomb July, 1959be useful, if one had a sufficient num-ber of such problems, to correlate den-tal and bone ages. The incidence ofpotential cuspid impactions also needsinvestigation; in my own case it isestimated to be in the ten to fifteenper cent range. The relatively smallnumber of patients in a one-manoffice does not attach reliability to thisestimate.In summary, early recognition andinterception of potential canine im-pactions is a highly useful by-productof routine cephalometric x-ray exam-ination. The lateral film alone cannot fill this function; the P.-A. filmprovides the necessary informationand may require supplementary den-tal x-rays. The proper time for re-moving the deciduous cuspids is mod-ified by the dental age of the patient.When extraction of the deciduouscuspid is ordered, it is often wise toask fcr removal of a generous amountof alveolar bone to favorably influencethe positions of the aberrant perma-nent teeth and to encourage their ulti-mate clinical appearance.13110 Shaker Square1.2.3.4.5.6.7.3.n Y.REFERENCESBroadbent, B. H. : The OrthodonticValue of Studies in Facial Growth; inPhysical and Meiitsl Adolescent Growth,Proc. of Conference on Adolescence,Cleveland, Ohio, 37-39: Oct. 1930.A New X-ray Technique and its Appli-cation to Orthodontia. Angle Ortho.,The Face of the Normal Child. AngleOrtho., 7 : 183 208 : 1937.The Eruption of the Teeth; in, FactorsInfluenczng Occlusion, Current Ad-vances in Dentistry, Univ. of Ill. Coll.of Dentastry Telephone Extension Pro-gram, Chicago, Ill., 50-55, 1951-52.Blum, Theodor : Malposed Teeth : TheirClassification, Pathology and Treatment.Internat. Jour. Ortho. and Oral Surg.9:122: 1923.Dewel, B. F.: The Upper Cuspid: ItsDevelopment and Impaction. AngleOrtho., 19 : 79-90 : 1949.Frantz, M. J. : Personal Communication.Noyes, F. B., Schour, I., and Noyes, 1%.J.: Dental Histology and Embryology,5th Ed., Lea 6 Pebiga, Philz. 1944.Rafcl, S. S.: The Unerupted Tooth.Archives of Orthodontics, 1 : 10-23 : 1952(Re-published in Angle Ortho., 4:201-211; 1953.)1 :15-65: 1931.TKl,:", VI uAO4 Zer?jimiri, .Jacobs. B. J., and