esearch- Based Updated Clinical PossibilitiesP The Herbst Appliance: ResearR Based on the bite jumping idea introduced by

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1 The Herst Appline: ReserR eserh- Bsed Updted Clinil PossiilitiesP Hns Pnherz, DDS, Odont Dr 1 /Sine Ruf, DDS, Dr med dent 2 Aim: To fous on the effiy of the Herst ppline in the tretment of Clss II mlolusions tht otherwise would hve een diffiult without tooth extrtions or orthognthi surgery mesures. Methods: Evidene-sed study nd review of our reent linil, ephlometri roentgenogrphi, nd mgneti resonne imging reserh. This reserh revels tht growth modifition with the Herst ppline is suessful in older Clss II ptients, who re generlly onsidered unresponsive to therpy with removle funtionl pplines. Conlusions: We suggest hnge in the urrent onept of Clss II tretment, with growth dpttion through use of the Herst ppline in hildren, dolesents, postdolesents, nd young dults. World J Orthod 2000;1: Bsed on the ite jumping ide introdued y Kingsley in 1877, Emil Herst developed his ppline in the erly 1900s nd presented it for the first time t the Interntionl Dentl Congress in Berlin in Twenty-five yers lter, in 1934, Herst wrote out his experienes with the ppline in 3 rtiles. After tht time, very little ws pulished out the sujet until Pnherz reintrodued the tretment method in Inititlly, Pnherz used the Herst ite jumping mehnism s sientifi tool in linil-experimentl orthodonti-orthopedi reserh. Through the yers, however, it eme ovious tht the ppline is most useful in the therpy of severe Clss II mlolusions. In omprison to onventionl funtionl pplines (eg, tivtor, iontor, Fränkel), the Herst ppline hs severl linil dvntges: The ppline is (1) fixed to the teeth, (2) works ontinuously 24 hours dy, (3) does not interfere with speeh, nd (4) requires no ptient ompline to ttin the desired tretment effets. 1 Professor, Deprtment of Orthodontis, University of Giessen, Giessen, Germny 2 Assoite Professor, Deprtment of Orthodontis, University of Giessen, Giessen, Germny REPRINT REQUESTS/CORRESPONDENCE Prof Dr Hns Pnherz, Deprtment of Orthodontis, University of Giessen, Shlngenzhl 14, D Giessen, Germny. Tel: Fx: E-mil: hns.pnherz@dentist.med.uni-giessen.de In 1979, Pnherz used nded design of the Herst ppline with simple nhorge system. In the mxillry dentl rh, the nhorge units on eh side omprised the first premolr nd the first permnent molr onneted to eh other y lingul setionl rh wire. In the mndiulr dentl rh, the first premolrs were interonneted y lingul rh wire touhing the lingul surfes of the nterior teeth. The telesoping tue ws tthed to the mxillry molr nd nd the plunger to the mndiulr premolr nd (Figs 1 nd 1). In 1982, the nhorge system of the nded Herst ppline ws hnged. In the mxill, the nines nd the inisors were inorported into the nhorge unit y pling rkets on the teeth nd onneting them to the premolr nds with lil setionl rh wire. In the mndile, the lingul rh wire ws extended to the first permnent molrs, whih lso were nded (Figs 1 nd 1d). In the modern Herst ppline, whih hs een used on regulr sis sine 1995, most teeth in the mxill nd mndile re inorported into the ppline for mximum nhorge. The nds hve een repled y st splints of olt-hromium lloy overing the teeth in the lterl segments. Additionlly, the mxillry nd mndiulr nterior teeth re inorported into the nhorge unit y onneting them to the splints with lil setionl rh wires. The xes for the telesoping tue nd plunger re soldered to the splints in the region of the mxillry first permnent molrs nd the mndiulr first premolrs, respetively (Figs 1e nd 1f). The splints re fixed to the teeth with glss-ionomer ement. 17

2 Pnherz/Ruf WORLD JOURNAL OF ORTHODONTICS d e f Fig 1 The nded Herst ppline with simple () mxillry nd () mndiulr nhorge. The nded Herst ppline with extended () mxillry nd (d) mndiulr nhorge. The st splint Herst ppline with ll (e) mxillry nd (f) mndiulr teeth inorported into nhorge. In omprison to the nded Herst ppline, the st splint ppline hs mny dvntges: It hs preise fit on the teeth, is strong nd hygieni, nd sves hir time euse it is esy to insert nd uses few linil prolems (no roken nds). Due to the higher lortory osts of the olthromium splints, ryli splints hve een dvoted y some liniins. However, ryli splints rek more esily nd re less hygieni. To overome the hygiene prolem, mny orthodontists use the ryli splint Herst ppline s removle ite jumping devie. However, the mjor dvntge of the Herst method, s fixed funtionl ppline, working 24 hours dy, independent of ptient oopertion, is lost with this dpttion. 18

3 VOLUME 1, NUMBER 1, 2000 Pnherz/Ruf Fig 2 Femle Clss II, Division 1 sujet, 16 yers of ge, treted with the st splint Herst ppline. Prsgittl MRIs of the right TMJ exhiiting physiologi disto-ondyle reltionship during different phses of therpy. () Before tretment. () Strt of tretment when the Herst ppline ws pled. () After 12 weeks of tretment. (d) After 7 months of tretment when the ppline ws removed. (e) One yer posttretment. Trings of the rtiulr strutures (ondyle, dis, foss) re given for etter orienttion. d e TREATMENT TMENT POSSIBILITIES In urrent dentofil orthopedis, Herst ppline therpy, followed y onventionl multirket ppline tretment phse, is most effiient 2- step pproh in the mngement of severe Clss II mlolusions. In the first step, Clss II orretion is omplished with the Herst ppline (6 to 8 months of therpy). Finl tooth lignment, in the seond step, is performed with onventionl multirket pplines (8 to 12 months of tretment). When the ppline is pled t the strt of Herst tretment, the mndile is usully dvned to n inisl edge-to-edge position nd the ondyles re positioned on the top of the rtiulr eminene. During the ourse of therpy, however, the ondyles return to their originl foss position. This is omplished y dptive dentl nd skeletl hnges: posterior movement of the mxillry dentition nd nterior movement of the mndiulr dentition, 1 stimultion of sgittl ondylr growth in more fvorle diretion, 2,3 nd remodeling of the glenoid foss. 3 Throughout tretment, norml dis-to-ondyle reltionship is mintined (Fig 2). At the end of tretment, the dis hs either returned to its originl pretretment position or hs ttined slightly retrusive position. 4 19

4 Pnherz/Ruf WORLD JOURNAL OF ORTHODONTICS Fig 3 Femle Clss II, Division 1 sujet, 13 yers of ge, treted with st splint Herst/multirket ppline system in omintion with rpid mxillry expnder. () Before tretment. () Strt of tretment when the st splints (without the telesope mehnism) were pled. () After 2 weeks of rpid mxillry expnsion (when the telesope mehnism ws pled). Note the distem nd the open ite. (d) After 6 months of Herst tretment, efore the ppline ws removed. (e) During the seond phse of tretment with multirket ppline. (f) After 18 months of Herst/multirket ppline tretment. (g) Retention with mxillry Hwley plte nd mndiulr nine-to-nine retiner. (h) Lterl hed films from efore tretment (left), fter the Herst tretment phse (middle), nd fter the multirket tretment phse (right). d e f g 20

5 VOLUME 1, NUMBER 1, 2000 Pnherz/Ruf h The Herst/multirket ppline pproh mkes it possile to tret severe Clss II mlolusions, whih otherwise would hve een very diffiult, if not impossile, to hndle without extrtion or orthognthi surgery. Our linil-experimentl reserh throughout the yers hs shown tht the Herst ppline is most useful in the Clss II sujets nd situtions desried elow. Clss II, Division 1 mlolusions This mlolusion is the min indition for Herst therpy. In ses with nrrow mxill, it is dvntgeous to omine the mxillry splints with rpid mxillry expnder (Fig 3) or qud-helix. In nlyzing the tretment effets in onseutively treted sujets, it hs een demonstrted tht Clss II orretion is the result of oth skeletl nd dentl hnges. 5 Skeletl hnges re more pronouned in erly dolesent sujets, nd dentl hnges re more pronouned in lte dolesent or young dult ptients 6 9 (Fig 4). In most Clss II, Division 1 ses, n undesirle side effet of the Herst ppline is the prolintion of the mndiulr inisors. This effet is the result of nhorge loss, due to the fores exerted y the telesope mehnism on the nterior teeth. The inisor prolintion is diffiult to ontrol 10 independently of the nhorge system used. However, no inresed inidene of mndiulr nterior rowding ould e found severl yers posttretment 10,11 despite spontneous uprighting of the teeth fter Herst therpy. Clss II, Division 2 mlolusions The Herst ppline is lso very effetive in Clss II, Division 2 ses 12 (Fig 5). In this type of mlolusion, the mndiulr inisors (s well s the mxillry inisors) hve retrolined position. Therefore, the mndiulr nhorge loss (prolintion of the mndiulr nterior teeth) during Herst tretment n e used dvntgeously to redue the interinisl ngle nd to rete stle nterior olusion. This would e prerequisite for the prevention of deep ite relpse (Fig 5). Furthermore, the hnges in inisor tooth ngultions during Herst therpy will improve the vertil lower lip to mxillry inisor reltionship (Fig 5). A high lip line (the lower lip overing the mxillry inisors) is ommon finding in Clss II, Division 2 mlolusions nd is onsidered to e oth n etiologi nd relpse ftor for deep ite. Therefore, the improvement in lip position will fvor the stility of the orreted overite High-ngle mlolusions Clss II mlolusions with hyperdivergent jw se reltionship re generlly onsidered to hve n unfvorle growth pttern, mking their tretment diffiult. As the Herst ppline hs een shown to inrese ondylr growth in the therpeutilly desired sgittl diretion 13 (Fig 6) without resulting in posterior (kwrd) rottion of the mndile, 14 high-ngle Clss II sujets re good ndidtes for suessful Herst therpy (Figs 7 nd 8). ry nterior rowding Besides the orthopedi effet on the mndile, the Herst ppline hs pronouned high-pull hedger effet on the mxillry molrs. 15 During therpy, the molrs re distlized nd signifintly intruded. The hedger effet is most useful in gining nterior spe nd relieving rowding in the mxillry nine nd inisor res (see we ppendix Fig A-1). 21

6 Pnherz/Ruf WORLD JOURNAL OF ORTHODONTICS Erly dolesent tretment (n = 25) Overjet orretion 9.8 mm Erly dolesent tretment (n = 25) Molr orretion 9.3 mm Skeletl 3.8 mm 39% Dentl 6.0 mm 61% Skeletl 3.8 mm 41% Dentl 5.5 mm 59% -0.5 mm -5% 4.3 mm 44% 3.3 mm 34% 2.7 mm 27% -0.5 mm -5% 4.3 mm 46% 3.0 mm 32% 2.5 mm 27% Lte dolesent tretment (n = 21) Overjet orretion 8.4 mm Lte dolesent tretment (n = 21) Molr orretion 6.1 mm Skeletl 2.3 mm 27% Dentl 6.1 mm 73% Skeletl 2.3 mm 38% Dentl 3.8 mm 62% -0.1 mm -1% 2.4 mm 28% 2.6 mm 31% 3.5 mm 42% -0.1 mm -1% 2.4 mm 39% 2.0 mm 33% 1.8 mm 29% Young dult tretment (n = 14) Overjet orretion 9.5 mm Young dult tretment (n = 14) Molr orretion 8.6 mm Skeletl 2.1 mm 22% Dentl 7.4 mm 78% Skeletl 2.1 mm 24% Dentl 6.5 mm 76% -0.2 mm -2% 2.3 mm 24% 3.6 mm 38% 3.8 mm 40% -0.2 mm -2% 2.3 mm 26% 2.7 mm 32% 3.8 mm 44% Fig 4 ry nd mndiulr skeletl nd dentl hnges ontriuting to overjet (left) nd sgittl molr (right) orretion in () 25 erly dolesent, () 21 lte dolesent, nd () 14 young dult sujets treted with the nded nd the st splint Herst pplines for period of 6 to 9 months. 6,8 Negtive ( ) vlues indite hnges ounterting overjet nd molr orretion. Fig 5 (Fing pge) Mle Clss II, Division 2 sujet, 14.5 yers of ge, treted with st splint Herst/multirket ppline system. () Before tretment. Note the high lip line (the lower lip overing the mxillry inisors). () Prolintion of the mxillry inisors. () During Herst tretment. Note 2 mndiulr dvnement shims dded to the plunger for retivtion of the telesope mehnism. (d) After 7 months of Herst tretment, when the ppline ws removed. Note the Clss I dentl rh overorretion, the lterl open ite, nd the improvement of the lower lip to mxillry inisor reltionship. (e) During the multirket phse of tretment. (f) After 2.4 yers of Herst/multirket ppline tretment. Note the stility of the lower lip to mxillry inisor reltionship. 22

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8 Pnherz/Ruf WORLD JOURNAL OF ORTHODONTICS "High ngle" tretment (n = 16) Overjet orretion 7.6 mm "High ngle" tretment (n = 16) Molr orretion 6.4 mm Skeletl 2.8 mm 37% Dentl 4.8 mm 63% Skeletl 2.8 mm 44% Dentl 3.6 mm 56% -0.2 mm -2% 3.0 mm 39% 1.8 mm 24% 3.0 mm 39% -0.2 mm -3% 3.0 mm 47% 1.5 mm 23% 2.1 mm 33% "Low ngle" tretment (n = 15) Overjet orretion 5.5 mm "Low ngle" tretment (n = 15) Molr orretion 5.7 mm Skeletl 1.4 mm 25% Dentl 4.1 mm 75% Skeletl 1.4 mm 25% Dentl 4.3 mm 75% -0.5 mm -9% 1.9 mm 34% 1.9 mm 35% 2.2 mm 40% -0.5 mm -9% 1.9 mm 34% 2.4 mm 42% 1.9 mm 33% Fig 6 ry nd mndiulr skeletl nd dentl hnges ontriuting to overjet (left) nd sgittl molr (right) orretion in () 16 high-ngle nd () 15 low-ngle Clss II, Division 1 mlolusions treted with the nded Herst ppline for period of 6 to 8 months. 12 Negtive ( ) vlues indite hnges ounterting overjet nd molr orretion. Fig 7 (Fing pge) Mle high-ngle Clss II, Division 1 sujet, 15 yers of ge, treted with nded Herst ppline in omintion with qud helix for mxillry expnsion (not shown). () Before tretment. () During Herst tretment. Note mndiulr dvnement shims dded to the plunger. () After 6 months of Herst tretment when the ppline ws removed. Note the Clss I overorretion nd the open ite. (d) At 6 months posttretment. Note the spontneous losure of the open ite. No multirket or retention pplines were used fter Herst tretment. 24

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10 Pnherz/Ruf WORLD JOURNAL OF ORTHODONTICS d e Fig 8 Mle high-ngle Clss II, Division 1 sujet, 14 yers of ge, treted with nded Herst/multirket ppline system in omintion with extrtion of the 4 first premolrs. () Before tretment. () Strt of Herst tretment when the ppline ws pled. () After 6.5 months of Herst tretment when the ppline ws removed. (d) After 12 months of multirket ppline tretment nd extrtion of the 4 first premolrs. (e) At 12 months posttretment. 26

11 VOLUME 1, NUMBER 1, 2000 Pnherz/Ruf Fig 9 Mle Clss II, Division 1 sujet, 13 yers of ge, treted with the Herst ppline for 6 months. The oy hs the prerequisites for fvorle profile tretment hnges: retrognthi hin, retrusive lower nd protrusive upper lips. (Left) Before tretment. (Right) After tretment. Fig 10 Femle Clss II, Division 1 sujet, 19 yers of ge, treted with the st splint Herst/multirket ppline system. Prsgittl MRIs of the right TMJ re shown. () Before tretment. () After 9 weeks of tretment. Note the remodeling of the ondyle nd rmus. () After 8 months of Herst tretment, when the ppline ws removed. Note tht the signs of remodeling hve susided. Retrognthi fil profile The exessive fil profile onvexity hrteristi of Clss II mlolusions is generlly redued y Herst therpy. 16 This effet is ovious oth in sujets treted during growth nd those treted t the end of growth ( lte tretment, desried elow). The most fvorle soft tissue profile hnges re seen in Clss II mlolusions with retrognthi hin, retruded lower lip, nd protruded upper lip (Fig 9). Postpuertl/Young dult ptients Herst therpy hs een shown to e very suessful not only in dolesent ptients, ut lso in postdolesent nd young dult ptients. 7 9 Although mndiulr growth is lmost ompleted in these older ptients, our reent mgneti resonne imging (MRI) studies hve shown 8 tht some ondylr growth n e retivted in sujets t the end of growth (Fig 10). 27

12 Pnherz/Ruf WORLD JOURNAL OF ORTHODONTICS % 40 Relpse Stle Fig 11 Digrm exhiiting the long-term results of Herst tretment with respet to stility nd relpse in overjet nd sgittl molr reltionship. Evlution of ptients 5 to 10 yers posttretment. Thirty-one sujets were treted erly (erly dolesene/ mixed dentition) nd 24 sujets were treted lte (lte dolesene/permnent dentition) Overjet Molr reltion Overjet Molr reltion Erly n = 31 Lte n = 24 Furthermore, in omprison to n erly tretment pproh (erly dolesene/mixed dentition), lte tretment (lte dolesene/permnent dentition) n more esily omplish stle posttretment uspl interdigittion, preventing relpse. 17,18 Additionlly, the retention time n e redued sine the residul growth period (with possile unfvorle growth pttern) is reltively short (Fig 11). In our opinion, fter extensive linil experienes, erly Clss II tretment should e performed with removle funtionl pplines (not the Herst ppline) euse these pplines re more effetive nd esier to hndle in young hildren. Herst tretment, on the other hnd, should e onfined to ptients who re in the puertl-postpuertl growth period nd hve their permnent dentition; t these lte somti nd dentl developmentl stges, removle pplines re less effiient nd ptient ompline is more diffiult. Alterntive to orthognthi surgery As mentioned ove, our reent linil, ephlometri roentgenogrphi, nd MRI reserh hs shown tht the Herst ppline is very effiient in Clss II sujets t the end of their growth (rdius union). 8,9 Thus, we onsider the method to e n lterntive to orthognthi surgery in mny dult Clss II sujets (Figs 12 nd 13). Our onvition is sustntited y the findings from n ongoing study tht ompres young Clss II dults treted with either the Herst ppline or with mndiulr sgittl split osteotomy. Comprle hnges in sgittl mxillry/mndiulr jw se reltionship nd skeletl profile onvexity were seen in the 2 groups t the end of tretment (fter finl tooth lignment with multirket pplines) (Fig 14). Furthermore, in omprison to surgery, Herst tretment implies lower osts nd lower risks for the ptient without inresing totl tretment time. TMJ ptients Our short- nd long-term TMJ reserh using tomogrphy 19 nd MRI 4,20 hs shown no dverse effets of Herst tretment on the different hrd nd soft tissue joint strutures. However, mny ses hve demonstrted tht Herst therpy results in retrusion of the rtiulr dis. 4 This effet n e used in the therpy of Clss II mlolusions with milder forms of nterior dis displement to ttin redution of the dis mlposition (Fig 15). NEW CONCEPT OF CLASS II THERAPY With respet to ge nd growth development, the dominnt urrent onept of Clss II tretment is: Growth dpttion in hildren nd dolesents Cmouflge orthodontis in postdolesents Surgil orretion in dults However, when onsidering the ft tht skeletofil growth ontinues mny yers fter esstion of ody height growth nd tht the dult TMJ is ple of remodeling, 8,9,21,22 it seems logil to revise the ove tretment onept. Thus, with respet to ge nd growth development, the following modified new onept for Clss II therpy is proposed: 28

13 VOLUME 1, NUMBER 1, 2000 Pnherz/Ruf Fig 12 Adult femle Clss II, Division 1 sujet, 18 yers of ge, treted with the st splint Herst/multirket ppline system. () Before tretment. () Strt of Herst tretment when the ppline ws pled. () After ompletion of Herst/multirket ppline tretment. Note the improvement in the hrd nd soft tissue profile. Totl tretment time ws 24 months. Fig 13 Adult femle Clss II, Division 1 sujet, 34 yers of ge, treted with the st Herst/multirket ppline system. () Before tretment. () During the Herst phse of tretment. () After ompletion of Herst/multirket ppline tretment. Note the improvement in the hrd nd soft tissue profile seen in the ephlogrm. Totl tretment time ws 15 months. 29

14 Pnherz/Ruf WORLD JOURNAL OF ORTHODONTICS Degrees mm Herst n = 12 Surgery n = 16 Wits Skeletl profile ngle Young dults / Clss II:1 Fig 14 Sgittl inter-jw se reltionship (Wits pprisl) nd skeletl profile onvexity (N-A-Pg). Chnges in young dults treted with either the st splint Herst ppline (n = 12) or with mndiulr sgittl split osteotomy (n = 16). Fig 15 Mle Clss II, Division 1 sujet, 12 yers of ge, with n nterior dis displement with redution. Tretment with the st splint Herst ppline. Anlyses of prsgittl TMJ-MRIs. () Before tretment. Note the nterior dis displement. () Strt of tretment when the Herst ppline ws pled. Note the dis redution omplished when the ondyle ws pled on the rtiulr eminene. () After 12 weeks of tretment. Note the return of the ondyle to its originl foss position nd the physiologi dis-to-ondyle reltionship. (d) After 7 months of Herst tretment when the ppline ws removed. Note the stility of the norml dis-to-ondyle reltionship. 18 d 30

15 VOLUME 1, NUMBER 1, 2000 Pnherz/Ruf Growth dpttion in hildren, dolesents, postdolesents, nd young dults Cmouflge orthodontis in older dults Surgil orretion in older dults Growth dpttion Growth dpttion should e performed with removle funtionl pplines in hildren nd dolesents with mixed dentition. However, in dolesents who hve their permnent dentition, in postdolesents, nd in young dults, the Herst ppline is usully indited. The pproximte ge for young dulthood would e 18 to 24 yers in femles nd 20 to 25 yers in mles. An upper ge limit for suessful Herst tretment is, however, diffiult to define (Fig 15). Cmouflge orthodontis Cmouflge orthodontis minly omprises tooth srifie in the mxillry dentl rh to rete spe for retrtion of the nterior teeth. By this pproh, however, the skeletl Clss II prolem (mndiulr retrusion) remins. Surgil orretion Surgil orretion implies tht the mndile is dvned to Clss I skeletl jw reltionship using either sgittl split osteotomy or mndiulr distrtion osteogenesis. Osionlly, mndiulr dvnement is omined with mxillry setk surgery (Le Fort I). The philosphil question is sed on potentil itrogeni sequele for primrily osmeti prolem: Wht prie surgery? REFERENCES 1. Pnherz H, Hnsen K. Olusl hnges during nd fter Herst tretment: A ephlometri investigtion. Eur J Orthod 1986;8: Pnherz H, Littmnn C. Morphologie und lge des unterkiefers ei der Herst-ehndlung. Eine kephlometrishe nlyse der veränderungen is zum whstumsshluss. Inf Orthod Kieferorthop 1989;21: Ruf S, Pnherz H. Temporomndiulr joint growth dpttion in Herst tretment: A prospetive mgneti resonne imging nd ephlometri roentgenogrphi study. Eur J Orthod 1998;20: Pnherz H, Ruf S, Thomlske-Fuert C. Mndiulr rtiulr dis position hnges during Herst tretment: A prospetive longitudinl MRI study. Am J Orthod Dentofil Orthop 1999;116: Pnherz H. The mehnism of Clss II orretion in Herst ppline tretment. A ephlometri investigtion. Am J Orthod 1982;82: Pnherz H, Hägg U. Dentofil orthopedis in reltion to somti mturtion. An nlysis of 70 onseutive ses treted with the Herst ppline. Am J Orthod 1985;88: Konik M, Pnherz H, Hnsen K. The mehnism of Clss II orretion in lte Herst tretment. Am J Orthod Dentofil Orthop 1997;112: Ruf S, Pnherz H. Temporomndiulr joint remodeling in dolesents nd young dults during Herst tretment: A prospetive longitudinl mgneti resonne imging nd ephlometri rdiogrphi investigtion. Am J Orthod Dentofil Orthop 1999;115: Ruf S, Pnherz H. Dentoskeletl effets nd fil profile hnges in young dults treted with the Herst ppline. Angle Orthod 1999;69: Pnherz H, Hnsen K. Mndiulr nhorge in Herst tretment. Eur J Orthod 1988;10: Hnsen K, Koutsons T, Pnherz H. Long-term effets of Herst tretment on the mndiulr inisor segment: A ephlometri nd iometri investigtion. Am J Orthod Dentofil Orthop 1997;112: Oijou C, Pnherz H. Herst ppline tretment of Clss II, Division 2 mlolusions. Am J Orthod Dentofil Orthop 1997;112: Ruf S, Pnherz H. The mehnism of Clss II orretion during Herst therpy in reltion to the vertil jw se reltionship: A ephlometri roentgenogrphi study. Angle Orthod 1997;67: Ruf S, Pnherz H. The effet of the Herst ppline on the mndiulr plne ngle. A ephlometri roentgenogrphi study. Am J Orthod Dentofil Orthop 1996;110: Pnherz H, Anehus-Pnherz M. The hed-ger effet of the Herst ppline. A ephlometri long-term study. Am J Orthod Dentofil Orthop 1993;103: Pnherz H, Anehus-Pnherz M. Fil profile hnges during nd fter Herst ppline tretment. Eur J Orthod 1994;16: Pnherz H. The nture of Clss II relpse fter Herst ppline tretment. A ephlometri long-term investigtion. Am J Orthod Dentofil Orthop 1991;100: Pnherz H. Früh- oder spätehndlung mit der Herst-Apprtur stilität oder rezidiv? Inf Orthod Kieferorthop 1994; 26: Hnsen K, Pnherz H, Petersson A. Long-term effets of the Herst ppline on the rniomndiulr system with speil referene to the TMJ. Eur J Orthod 1990;12: Ruf S, Pnherz H. Long-term TMJ effets of Herst tretment: A linil nd MRI study. Am J Orthod Dentofil Orthop 1998;114: Woodside DG, Altun G, Hrvold E, Herert M, Metxs A. Primte experiments in mlolusion nd one indution. Am J Orthod 1983;83: MNmr JA Jr, Hinton RJ, Hoffmn DL. Histologil nlysis of temporomndiulr joint dpttion to protrusive funtion in young dult rhesus monkey (M multt). Am J Orthod 1982;82:

16 Pnherz/Ruf WORLD JOURNAL OF ORTHODONTICS WEB APPENDIX d e f Fig A-1 Femle Clss II, Division 1 sujet, 15 yers of ge, with lmost omplete spe losure, fter trumti loss of the left permnent mxillry entrl inisor t the ge of 10 yers. Tretment with the st splint Herst/multirket ppline system in omintion with rpid mxillry expnder. () Before tretment. () Strt of tretment with the Herst ppline nd the mxillry expnder were pled. () During Herst tretment. Note the trnsverse mxillry expnsion nd the spes tht developed distlly to the mxillry nines s result of the hedger effet of the Herst ppline moving the lterl teeth posteriorly. (d) After 12 months of Herst tretment, when the ppline ws removed. Note the overorreted Clss I dentl rh reltionships nd the spe opening for the left entrl inisor. (e) During the multirket phse of therpy. Note the mxillry plte repling the missing entrl inisor. (f) After 6 months of multirket ppline tretment. Note the omplete spe opening for the entrl inisor, nd the orretion of the midline nd the Clss I dentl rh reltionships. After ompletion of growth, n inisor implnt in plnned. 32