Tvorba kosti ortodontickyâ m posunem zubu a jejõâ stabilita vcï ase Bone formation by orthodontic tooth movement and its stability in time

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1 Tvorba kosti ortodontickyâ m posunem zubu a jejõâ stabilita vcï ase Bone formation by orthodontic tooth movement and its stability in time MUDr.SonÏ a NovaÂcÏ kovaâ *, MUDr.Ivo Marek*, prof.mudr.milan KamõÂnek, DrSc.*, Mgr.KaterÏina LangovaÂ** *Ortodonticke oddeï lenõâ Kliniky zubnõâho leâkarïstvõâ LF UP Olomouc, CÏ eskaâ republika **Katedra fyziky TU LF UP Olomouc *Department of Orthodontics, Clinic of Dental Medicine, Medical Faculty, Palacky University, Olomouc, CR ** Department of Physics, Medical Faculty, Palacky University, Olomouc Souhrn CõÂl praâ ce: Tato studie popisuje rozmeï roveâ zmeï ny alveolaâ rnõâho vyâbeï zïku v cï ase u pacientuê s agenezõâ hornõâch lateraâ lnõâch rïezaâ kuê leâ cï enyâ ch fixnõâm ortodontickyâ m aparaâ tem. CõÂlem studie bylo zjistit : 1. ZmeÏ ny kostnõâ masy ve vertikaâ lnõâ a horizontaâ lnõâ rovineï beï hem ortodontickeâ leâcï by fixnõâm aparaâ tem a v naâ sledneâ retencïnõâfaâ zi. 2. Zda sklon sï picï aâ ku a vzdaâ lenost sï picï aâ ku od centraâ lnõâho rïezaâ ku prïed leâ cï bou majõâ vliv na mnozï stvõâ kosti vytvorïeneâ distalizacõâ hornõâho sï picïaâ ku a na stabilitu kostnõâ masy v cï ase. Metodika: Data byla zõâskaâ na ze saâ drovyâ ch modeluê hornõâ cï elisti a ortopantomogramuê 80 pacientuê s celkem 128 stranami ageneze lateraâ lnõâch rïezaâ kuê, zhotovenyâ ch ve trïech cï asovyâ ch periodaâ ch: (T1) na zacï aâ tku ortodontickeâ leâcï by, (T2) na konci ortodontickeâ leâcï by, (T3) v dobeï retence - 2 roky po ukoncï enõâ leâcï by (T3A), 5 let po leâcïbeï (T3B). MeÏrÏena byla vzdaâ lenost sï picïaâ ku od centraâ lnõâho rïezaâ ku. Vestibuloora lnõâ sïõârïka alveolu byla meïrïena na saâdroveâ m modelu v uâ rovni kostnõâho hrïebene alveolu a v mõâsteï 5mm apikaâ lneï od hrïebene alveolu. Na OPG snõâmcõâch byl registrovaâ n sklon sï picïaâ ku k alveolaâ rnõâmu hrïebeni a vyâsï ka alveolaâ rnõâho hrïebene. Vy sledky: Byl zjisïteï n pokles sïõârïky alveolaâ rnõâho hrïebene o 4 % v obdobõâ od zahaâ jenõâ do ukoncï enõâ ortodontickeâ leâ cï by (T1-T2) a dalsï õâ pokles pruê meï rneï o 2 % v dobeï retence (T2-T3A, T2-T3B) s individuaâ lnõâ variabilitou. Pokles vyâsïkyhrïebene v mõâsteï ageneze byl 0,26 mm na konci leâcï by (T1-T2), v dobeï 5 let po leâcïbeï pruêmeï rneï 0,38mm (T2- T3B). Nebyl nalezen vztah mezi sklonem sï picïaâ ku ani vzdaâ lenostõâ sï picïaâ ku od centraâ lnõâho rïezaâ ku na zacïaâ tku leâcïby a mnozïstvõâm kosti a stabilitou teâ to kostnõâ masy vytvorïeneâ ortodontickyâ m posunem. ZaÂveÏr:Kost vytvorïenaâ ortodontickyâ m posunem zubu je stabilnõâ ve smeï ru horizontaâ lnõâm i vertikaâ lnõâm. ZmeÏny sïõârïky alveolu nebyly zaâ visleâ na mnozïstvõâ kosti v mõâsteï ageneze prïi zahaâ jenõâ leâcï by. Pokud tedy sï picïaâ k prorïezïeteï sneï vedle centraâ lnõâho rïezaâ ku, jsou podmõânky pro vytvorïenõâ dostatecï neâ kosti distalizacõâ sï picï aâ ku v mõâsteï nezalozï eneâ ho lateraâ lnõâho rïezaâkuprïõâzniveïjsïõâ(ortodoncie 2008, 17, cï. 2, s ). Abstract Aim: Changes in parameters of alveolar process over the period of time in patients with missing maxillary lateral incisors are examined. The patients were treated with fixed orthodontic appliance. The aim was to find out: 1. Changes in bone mass in both vertical and horizontal planes during orthodontic treatment with fixed appliances, and during the following period of retention. 2. Whether the canine inclination and its distance from the central incisor before treatment affect the amount of bone created through distalization of maxillary canine, and the bone mass stability in time. Method: The relevant data were obtained from casts of maxilla and pantomographic pictures of 80 patients with the total of 128 sides with missing lateral incisors. The casts were made in the three periods: (T1) at the be- redakce@orthodont-cz.cz 11

2 ORTODONCIE ginning of the orthodontic treatment, (T2) at the end of orthodontic treatment, (T3) during the period of retention - 2 years after treatment (T3A), 5 years after treatment (T3B). The distance between the canine and the central incisor was measured. Vestibulooral width of alveolus was measured in casts at the level of bone ridge of the alveolus and at the point 5 mm apically off the alveolar ridge. In OPG the canine inclination to the alveolar ridge was recorded, as well as the height of the alveolar ridge. Results: The reduction of the alveolar ridge width by 4% was registered within the period between the beginning and the end of orthodontic treatment (T1-T2); in the period of retention the reduction was 2% on average (T2- T3A, T2-T3B), with individual variance. At the end of treatment (T1-T2) the height of the alveolar ridge decreased by 0.26 mm; 5 years after treatment the height decreased by 0.38 on average (T2-T3B). There was found no relation between the canine inclination or between the canine distance from the central incisor at the beginning of treatment and the amount and stability of the bone created by the orthodontic movement. Conclusion: The bone created through the orthodontic tooth movement is stable in both horizontal and vertical directions. Changes in the width of the alveolus were not related to the amount of bone at the place of agenesis at the beginning of treatment. Therefore, if the canine erupts next to the central incisor, there are more favorable conditions affecting formation of the bone mass through distalization of the canine at the place of the missing lateral incisor (Ortodoncie 2008, 17, No. 2, p ). KlõÂcÏ ovaâ slova: ageneze hornõâch lateraâ lnõâch rïezaâkuê, zmeï ny alveolaâ rnõâho hrïebene v cï ase, sklon a vzdaâ lenost sï picïaâ ku, stabilita kosti, ortodontickyâ posun zubu Key Words: missing maxillary lateral incisors, changes of alveolar ridge in time, canine inclination and distance, bone stability, orthodontic tooth movement U vod Tvorbakosti je normaâ lnõâm histologickyâ m procesem resorpce aapozice kosti, kteryâ vznikaâ vyrovnanou osteoklastickou a osteoblastickou aktivitou [1]. Ortodonticky m bodily posunem, pohybem zubu v kosti alveolaâ rnõâho vyâbeï zï ku horizontaâ lneï, dochaâ zõâ k vytvorïenõâ noveâ kosti v draâ ze jeho posunu ak zachovaâ nõâ kosti v sïõârïce posunovaneâ ho zubu [2, 3]. DochaÂzõ k tomu i tam, kde puê vodneï byl zuâzï enyâ alveol ve tvaru prïesyâpacõâch hodin [1]. U pacientuê s diagnoâ zou ageneze hornõâch lateraâ lnõâch rïezaâ kuê maâ me neï kolik leâ cï ebnyâ ch mozï nostõâ. PrÏedevsÏ õâm se musõâme rozhodnout zdamezeru uzavrïeme meziaâlnõâm posunem sï picï aâ ku anebo ji ponechaâ me otevrïenou a mõâsto ageneze nahradõâme neï kteryâ m z typuê protetickeâ naâ hrady. Mezi mozïneâ eventuality patrïõâ adhezivnõâ naâhrady, konvencï nõâ fixnõâ muê stky anebo implantaâ ty. KazÏ daâ z teï chto mozï nostõâ podleâ haâ urcï ityâ m kriteâ riõâm, kteraâ bylaprobraâ na v nasï ich trïech prïedesï lyâ ch souhrnnyâch sdeï lenõâch [4, 5, 6]. JednõÂm z kritickyâch faktoruê prïi rozhodovaâ nõâ je prïõâslusï nyâ prostor v mõâsteï ageneze. A praâveï zde hraje zaâ sadnõâ roli ortodontickaâ leâcï ba, kteraâ zajistõâ pozï adovaneâ mõâsto posunem zubuê do ideaâ lnõâ polohy podle plaânuleâcï by. VõÂme, zïe po extrakci zubu dochaâ zõâ k resorpci alveolaâ rnõâho vyâbeïzïku o 23 % v prvnõâch 6 meï sõâcõâch ak v pruêbeïhunaâ sledujõâcõâch peï ti let dochaâzõâkuâ bytku asi o 11 % [7]. Celkova ztraâtatakje34%zsïõârïky alveolu ve vestibulooraâ lnõâm smeï ru a daâ le pokracï uje. Ortodonticky posun zubu je schopen vytvorïit kost. Po ortodontickeâ m posunu zubu, jak ukazuje studie Spearse, Mathewse a Kokiche, je ve vestibulooraâ lnõâm Introduction Bone formation is a normal histological process of resorption and apposition of the bone which arises due to the balanced osteoclastic and osteoblastic activity [1]. By an orthodontic bodily movement, i.e. by a horizontal movement of a tooth in the alveolar process, the new bone forms in the path of its movement, and the bone is retained along the width of the tooth moved [2, 3]. This holds true even in case the alveolus was narrowed [1]. There are different types of treatment that can be applied in the patients with missing maxillary lateral incisors. E.g. substitution of the missing incisor with canine, adhesive bridges, conventional fixed bridges, or implants. The choice of the approach depends on the relevant criteria that were discussed in our three studies published earlier [4, 5, 6]. A space at the place of agenesis is one of the most important factors. The orthodontic treatment plays the fundamental role here, as it provides the space required by means of tooth movement into the ideal positions according to the treatment plan. We know that after a tooth extraction, the resorption of the alveolar process occurs by 23% during the first 6 months; the loss during the following 5 years represents approx. 11% [7]. The overall loss thus reaches 34% and is progressive. The orthodontic tooth movement may lead to the creation of bone. Spears, Mathews, and Kokich [8] reported that after the orthodontic tooth movement the loss in vestibulooral dimension is less than 1% over redakce@orthodont-cz.cz

3 rozmeï ru ztraâ tamensï õâ nezï 1 % v pruêbeï hu 4 let [8]. To znamenaâ,zï e jestlizï e muê zï eme v mõâsteï budoucõâ implantace pohybovat se zubem, je to pro budoucõâ implantaci mnohem vyâ hodneï jsï õâ situace nezï ponechat mõâsto po ztraâ teï docï asnyâ ch lateraâ lnõâch rïezaâ kuê bez dalsï õâho ortodontickeâ ho posunu. TeÏ lesnyâ posun korïene sï picï aâ ku vytvaâ rïõâ adekvaâ tnõâ sï õârïku alveolaâ rnõâho hrïebene [2, 3]. Tento postup, kteryâ oznacï ujeme jako ortodontickyâ vyâ voj prostoru pro implantaâ t, naâ m zajistõâ dostatecï nou tvorbu kosti, kteraâ je navõâc stabilneïjsï õâ [3, 8]. CõÂlem nasï õâ studie bylo zjistit: 1. ZmeÏ ny kostnõâ masy ve vertikaâ lnõâ ahorizontaâ lnõâ rovineï beï hem ortodontickeâ leâcï by fixnõâm aparaâ tem av naâ sledneâ retencïnõâ faâ zi. 2. Zdasklon sï picïaâ ku avzdaâ lenost sï picïaâ ku od centraâ lnõâho rïezaâ ku prïed leâ cï bou majõâ vliv na mnozï stvõâ kosti vytvorïeneâ distalizacõâ hornõâho sï picï aâ ku anastabilitu kostnõâ masy v cï ase. Materia l a metodika Data pro meï rïenõâ bylazõâskaâ naze saâ drovyâ ch modeluê arentgenovyâ ch OPG snõâmkuê 128 agenetickyâ ch stran 80 pacientuê. Vzorek byl shromaâzïdeï n z ortodontickeâho oddeï lenõâ Kliniky zubnõâho leâ ka rïstvõâ v Olomouci, daâ le pa k zpeï ti privaâ tnõâch ortodontickyâch ordinacõâ. U ka zïdeâ ho pacienta byly zhotoveny 3 saâ droveâ modely aty byly opeï tovneï odlity. Vlastnõ meï rïenõâ bylarealizovaâ nanamodelech hornõâho zubnõâho oblouku. Prvnõ model byl zhotoven prïi zahaâ jenõâ ortodontickeâ leâ cï by (v cï ase T1). Druhy model byl zhotoven nakonci aktivnõâ faâ ze ortodontickeâ leâ cï by, po sejmutõâ fixnõâho aparaâtu (v cï ase T2). TrÏetõ model byl zhotoven v obdobõâ retence (v cï ase T3). CÏ as T3 byl rozdeï len do dvou skupin, ato 2 roky po leâcïbeï(cï as T3A) a 5 let po leâcïbeï(cï as T3B). OPG snõâmky byly zhotoveny nazacï aâ tku leâ cï by (T1), nakonci leâcï by (T2), v dobeï 2 roky (T3A) nebo 5 let (T3B) po leâcïbeï.veï kovyâ rozsah u pacientuê nazacïaâ tku leâcï by (T1) byl 11,2 azï 31,2 let, s pruêmeï rem 18,06 let, nakonci leâcï by (T2) 13,1 azï 32,5 let, s pruê meï rem 19,8 let. V dobeï retence (T3) byl veï kovyâ rozsah 16,2 azï 34,9 let, s pruêmeï rem 23,83 let. Krite riapro zarïazenõâ do souboru: 1. VsÏ ichni pacienti meï li alesponï jednostrannou agenezi hornõâho lateraâ lnõâho rïezaâ ku adokoncï enou ortodontickou leâcï bu fixnõâm aparaâ tem 2. ZpuÊ sobem leâcï by byla distalizace sï picïaâ ku aangleovai.trïõâdave sï picïaâ cõâch po ortodontickeâ leâcïbeï 3. CÏ itelneâ panoramatickeâ snõâmky asponï ze dvou sledovanyâch obdobõâ 4. Kvalitnõ saâ droveâ modely z nejmeâneï dvou sledovanyâ ch obdobõâ umozï nï ujõâcõâ dublovaâ nõâ 5. NasÏ picï aâ cõâch se neprovaâ deï l zïaâ dnyâ rekonturing ani zaâ brus 4 years. That means that if we can move with a tooth at the place of the future implant, it is much more favorable situation than to leave the place, after the loss of temporary lateral incisors, without an orthodontic movement. Bodily movement of the canine root contributes to the adequate width of the alveolar ridge [2, 3]. The approach, i.e. the orthodontic creation of the space for the implant, makes sufficient formation of the bone possible. Moreover, the bone is also more stable [3, 8]. The aim of our work was to find out: 1. Changes in the bone mass in both vertical and horizontal planes during the orthodontic treatment with fixed appliance, and during the following period of retention. 2. Whether the canine inclination and its distance from the central incisor before treatment affect the amount and stability of the bone created through distalization of maxillary canine. Material and method The data were obtained from casts of upper jaw and OPG of 80 patients with the total of 128 sides with missing lateral incisors. The material comes from the Department of Orthodontics, Clinic of Dental Medicine in Olomouc, and from five private orthodontic practices. For each patient 3 models were prepared and cast. Measurements were done in the casts of the upper dental arch. The first cast was made at the beginning of orthodontic treatment (T1). The second cast was made at the end of active orthodontic treatment, after the fixed orthodontic appliance was removed (T2). The third cast was made during the period of retention (T3). Time T3 was subdivided into two groups - 2 years after treatment (T3A), and 5 years after treatment (T3B). Pantomographic pictures (OPG) were taken at the beginning of treatment (T1), at the end (T2), and 2 years (T3A) and 5 years (T3B) after treatment. The range of patients' age at the beginning of treatment (T1) was between 11.2 and 31.2 years, mean age was years; at the end of treatment (T2) between 13.1 and 32.5 years, mean age at 19.8 years. During the period of retention it was between 16.2 and 34.9 years, mean value at years. Criteria: 1. All patients suffered from at least unilateral agenesis of maxillary lateral incisor, and they finished the orthodontic treatment with fixed appliance. 2. The treatment involved canine distalization and normoocclusion in canines after treatment was reached. 3. Good quality legible OPG taken at least during two different periods of time. 4. Good quality casts made at least during two different periods of time, so as to enable doubling. 5. Canines were not recontoured or grinded. redakce@orthodont-cz.cz 13

4 ORTODONCIE Kontrolnõ skupina: U 25 pacientuê s jednostranou agenezõâ byla promeïrïenai druhaâ strana. MeÏrÏilase zmeï na sï õârïky alveolaâ rnõâho hrïebene v mõâsteï sï picï aâ ku alateraâ lnõâho rïezaâ ku strany bez ageneze. PodmõÂnkou tedy bylaprïõâtomnost lateraâ lnõâho rïezaâ ku na meï rïeneâ straneï aprobeï hlaâ leâ cï ba fixnõâm aparaâ tem. Tato skupina byla oznacï enajako skupinakontrolnõâ. AnalyÂzasa drovyâ ch modeluê Namodelech bylameï rïenavzdaâ lenost mezi sï picï aâkem acentraâ lnõâm rïezaâ kem v mõâsteï sliznice alveolaâ rnõâho hrïebene v cï ase T1, T2, T3 pomocõâ digitaâ lnõâho posuvneâhomeïrïõâtka. Da le bylameï rïenasï õârïkaalveolaâ rnõâho hrïebene v mõâsteï ageneze hornõâho lateraâ lnõâho rïezaâ ku v bodeï A (hladina kostnõâho hrïebene alveolu = 1mm apikaâ lneï od cementosklovinneâ hranice) a v bodeï B( v mõâsteï 5mm apikaâ lneï od hrïebene alveolu) (Obr. 1-5). Tyto body meï rïeneâ na modelech byly nejdrïõâve identifikovaâ ny pomocõâ rentgenovyâ ch snõâmkuê. Na ortopantomogramu v cï ase T1 zmeï rïõâme vzdaâ lenost mezi hrotem sï picï aâ ku aalveolaâ r- nõâm hrïebenem sï picïaâ ku (v bodeï A) v dlouheâ ose zubu avzdaâ lenost mezi hrotem sï picïaâ ku abodem 5 mm apikaâ lneï odhrïebene alveolu (v bodeï B) v dlouheâ ose zubu. Stejne meï rïenõâ provedeme pro strïednõâ rïezaâ k (Obr. 1). Dlouhou osu sï picï aâ ku astrïednõâho rïezaâ ku si nakreslõâme namodely T1, T2, T3, kde naâ m k orientaci slouzï õâ ko- Control group: In 25 patients with unilateral agenesis, the opposite side was measured, too. We measured the change in width of the alveolar ridge at the place of the canine and the lateral incisor in the normal side. The lateral incisor at the side which was subject to measurements had to be present, and the patients underwent orthodontic treatment with fixed appliance. This group of patients was taken as the control one. Casts analysis The distance between the canine and the central incisor was measured in casts at the place of the alveolar ridge mucosaat the times T1, T2, T3, with the help of a digital calliper. The width of the alveolar ridge at the place of the missing maxillary lateral incisor was measured at the point A (level of bony alveolar ridge = 1 mm apically off the cement-enamel junction) and at the point B (5 mm apically off the alveolar ridge) (Fig. 1-5). The points measured in the casts were first determined by means of OPG. In an OPG at time T1 we measure the distance between the tip of the canine and the canine alveolar ridge (at the point A) in the long axis of the tooth, and the distance between the tip of the canine and the point located 5 mm apically off the alveolar ridge (at the point B) in the long axis of the tooth. The same measurements are carried out for the central incisor (Fig. 1). Obr.1.Vzda lenost mezi hrotem sï picï aâ ku a alveolaâ rnõâm hrïebenem sï picïaâ ku ( bod A ) v dlouheâ ose zubu a vzdaâ lenost mezi hrotem sï picïaâ ku a bodem 5mm apikaâ lneï odhrïebene alveolu ( bod B ) v dlouheâ ose zubu, stejneâ i pro centraâ lnõâ rïezaâk Fig.1.The distance between the canine tip and the canine alveolar ridge (point A) in the long axis of the tooth, and the distance between the canine tip and the point located 5 mm apically off the alveolar ridge (point B) in the long axis of the tooth, identical for the central incisor. Obr.2.Spojnici boduê A a B mezi sï picïaâ kem a centraâ lnõâm rïezaâ kem naâ m urcï õâ bod A a bod B na vestibulaâ rnõâ straneï v mõâsteï ageneze. PrÏõÂklad na modelu v cï ase T2 Fig.2.The connecting line of the points A and B between the canine and central incisor is determined by the points A and B on the vestibular side at the place of agenesis. Example at T2. Obr.3.Spojnici boduê Ai a Bi mezi sï picïaâ kem a centraâ lnõâm rïezaâ kem naâ m urcï õâ bod Ai a bod Bi na palatinaâ lnõâ straneï v mõâsteï ageneze. PrÏõÂklad na modelu v cï ase T1 Fig.3.The connecting line of the points Ai and Bi between the canine and central incisor is determined by the points Ai and Bi on the palatal side at the place of agenesis. Example at T redakce@orthodont-cz.cz

5 Obr.4.Spojenõ boduê A-Ai a boduê B-Bi v mõâsteï ageneze Fig.4.Connecting lines A-Ai and B-Bi at the place of agenesis Obr.5.Spojenõ boduê A-Ai a boduê B-Bi v mõâsteï sï picïaâku Fig.5.Connecting line A-Ai and B-Bi at the place of canine runkaaalveolaâ rnõâ hrïeben atyto nameï rïeneâ vzdaâ lenosti prïeneseme nasaâ droveâ modely zhotoveneâ v cï ase v T1, T2, T3, ato z vestibulaâ rnõâ i palatinaâ lnõâ strany. V mõâsteï ageneze vedeme linii svisle ve strïedu spojnice mezi sliznicõâ alveolaâ rnõâho hrïebene sï picï aâ k - centraâ lnõâ rïezaâ k akolmo naokluznõâ rovinu. Linie vedenaâ ze strïedu agenetickeâ ho mõâstake spojnici teï chto boduê mezi sï picï aâkem acentraâ lnõâm rïezaâ kem naâ m urcï õâ bod A abod B navestibulaâ rnõâ straneï abod Ai abi napatroveâ straneï v mõâsteï ageneze (Obr. 2-3). Sa droveâ modely T1, T2, T3 byly rozrïezaâ ny svisle ve strïedu spojnice mezi sliznicõâ alveolaâ rnõâho hrïebene sï picï aâ k - centraâ lnõâ rïezaâ k akolmo naokluznõâ rovinu atakeâ v mõâsteï zakresleneâ dlouheâ osy sï picï aâ ku. NapruÊ rïezu modeluê T1, T2, T3 se spojily body A-Ai abody B-Bi v mõâsteï ageneze a zvlaâ sï t' v mõâsteï sï picï aâ ku. Spojnice A-Ai prïedstavuje sïõârïku alveolu v bodeï A (meïrïeno pro mõâsto ageneze a pro sï picïaâ k ). Spojnice B-Bi prïedstavuje sïõârïku alveolu v bodeï B (meïrïeno pro mõâsto ageneze apro sï picïaâ k ) (Obr. 4-5). AnalyÂza ortopantomogramu NaOPG snõâmcõâch bylameï rïenavyâsï kaalveolaâ rnõâho hrïebene v mõâsteï ageneze v cï ase T1, T2, T3 tak, zïe byla zakreslena linie mezi cementosklovinnyâ mi hranicemi (CEJ) zubuê sousedõâcõâch s bezzubyâ m mõâstem. Natuto linii bylaspusïteï nakolmice ve strïedu agenetickeâho mõâsta. MeÏrÏenabylavzda lenost vrcholu alveolaâ rnõâho hrïebene ve strïedu mõâstaageneze ke spojnici CEJ sï picï aâk - centraâ lnõâ rïezaâ k (Obr. 6). MeÏrÏen byl takeâ sklon sï picïaâ ku k alveolaâ rnõâmu hrïebeni. Byl definovaâ n jako uâ hel, kteryâ svõâraâ axiaâ lnõâ osa sï picïaâ ku s lõâniõâ prochaâ zejõâcõâ hrïebenem alveolu (Obr. 7). ChybameÏrÏenõ Ze studijnõâho vzorku bylo naâ hodneï vybraâ no 26 jedincuê s modely aopg snõâmky v cï ase T1, T2, T3. Modely byly znovu dublovaâ ny avesï keraâ meï rïenõâ bylazopakovaâ nastejnou osobou s odstupem dvou tyâdnuê. OPG snõâmky byly opeï tneï promeïrïeny stejnou osobou s od- The long axis of the canine and the central incisor is traced on the casts T1, T2, T3 - the crown and alveolar ridge help in orientation. The values taken are traced on casts made at T1, T2, T3, from both vestibular and palatal sides. At the place of agenesis we trace the line vertically in the middle of the connecting line between the alveolar ridge mucosa canine-central incisor, and perpendicular to the occlusal plane. The line running from the middle of the place of agenesis to the connecting line of the points between the canine and central incisor determines the points A and B on the vestibular side, and Ai and Bi on the palatal side at the place of agenesis (Fig. 2-3). The casts T1, T2, T3 were cut vertically in the middle of the connecting line between the mucosaof the alveolar ridge canine - central incisor, and perpendicular to the occlusal plane, as well as at the place of the canine long axis tracing. In the cross section of the casts T1, T2, T3 there were connected the points A-Ai and B- Bi at the place of agenesis, especially at the place of the canine. The connecting line A-Ai is the width of the alveolus at the point A (measured for the place of agenesis and for the canine). The connecting line B- Bi is the width of the alveolus at the point B (measured for the place of agenesis and for the canine) (Fig. 4-5). OPG analysis In OPG, the height of the alveolar ridge at the place of agenesis at T1, T2, T3 was measured in the following way: the line between cement-enamel junctions (CEJ) of the teeth adjacent to the toothless place was traced. At the place of agenesis, a perpendicular was drawn onto the line. We measured the distance between the top of the alveolar ridge in the middle of the agenesis and the connecting line CEJ canine-central incisor (Fig. 6). We also measured the canine inclination to the alveolar ridge. It was defined as the angle between the axial of the canine and the line running through the alveolar ridge (Fig. 7). redakce@orthodont-cz.cz 15

6 ORTODONCIE Obr.6.MeÏrÏenõ vyâsï ky alveolaâ rnõâho hrïebene v mõâsteï ageneze Fig.6.Measurement of the alveolar ridge height at the place of agenesis. stupem nejmeâ neï dvou tyâ dnuê. Byla stanovena statistickaâ analyâ zarozdõâluê mezi puê vodnõâm meï rïenõâm ameï rïenõâm opakovanyâm. ChybameÏrÏenõ (S x ) byla vypocïõâtaâna podle Dahlbergovy formule: kde D je rozdõâl mezi puê vodnõâm aopakovanyâm meïrïenõâm an je pocï et opakovanyâch meï rïenõâ [9]. ChybameÏrÏenõ sï õârïky alveolaâ rnõâho hrïebene v mõâsteï agenetickeâ ho rïezaâ ku byla0,33 mm, v mõâsteï sï picïaâ ku 0,25 mm. Pro meïrïenõâ vzdaâ lenostõâ na ortopantomogramu byla chyba meïrïenõâ0,51 mm, pro meïrïenõâuâ hluê 4. Hodnoty byly uvaâzï eny jako prïijatelneâ pro dalsïõâmeïrïenõâ. Statisticke zpracovaânõâ ZmeÏ nasï õârïky bezzubeâ ho alveolaâ rnõâho hrïebene v danyâch bodech A ab v cï asovyâch periodaâ ch T1, T2, T3 bylahodnocenapaâ rovyâ m parametrickyâ m t-testem. Stejne hodnocenõâ zmeï ny sï õârïky alveolaâ rnõâho hrïebene bylo provedeno i v mõâsteï alveolaâ rnõâho hrïebene sï picï aâ ku apro kontrolnõâ skupinu. Pomocõ znameâ nkoveâ ho testu byly porovnaâ vaâ ny zmeï ny vyâsï ky alveolaâ rnõâho hrïebene v mõâsteï ageneze v danyâch cï asovyâch periodaâ ch. DalsÏ õâm krokem statistickeâho meï rïenõâ byla analyâza zaâ vislosti vzdaâ lenosti sï picï aâ ku od strïednõâho rïezaâku na zacï aâ tku leâ cï by (T1) amnozï stvõâ vytvorïeneâ kosti (T2) astability teâ to kostnõâ masy (T3A a T3B) pomocõâ dvouvyâbeï roveâ ho t-testu akorelacï nõâ analyâzy. Ke zjisïteï nõâ statistickeâ vyâznamnosti vztahu mezi sklonem sï picïaâkuna zacï aâ tku leâ cï by (T1) amnozï stvõâm vytvorïeneâ kosti (T2) avztahu mezi sklonem sï picïaâku v cï ase T1 a stabilitou vytvorïeneâ kostnõâ masy (T3) byla pouzï ita metoda analyâ zy rozptylu (ANOVA). Hodnocenabylai korelace sklonu sï picï aâ ku ajeho vzdaâ lenosti od strïednõâho rïezaâ ku nazacï aâ tku leâ cï by namnozï stvõâ kosti vytvorïeneâ distalizacõâ sï picï aâ ku v mõâsteï ageneze korelacï nõâ analyâ zou. Testova nõâ signifikace bylo provaâdeï no na0,1%, 1% a5% hladineï vyâznamnosti (p < 0,001; 0,01; 0,05). Obr.7.MeÏrÏenõ uâ hlu sï picïaâ ku k alveolaâ rnõâmu hrïebeni ( sklon sï picïaâku) Fig.7.Measurement of the angle between the canine and the alveolar ridge (canine inclination) Measurement error 26 individuals with casts and OPG made at T1, T2, T3 were randomly chosen from the sample of patients. The casts were doubled again and all measurements were repeated after two weeks and carried out by the same person. OPG were measured repeatedly after two weeks by the same person. Statistical analysis of the differences between the first and repeated measurements was performed. To calculate the measurement error (S x ) we used the Dahlberg formula: where D is the difference between the original and control measurements, and N is the number of repeated measurements [9]. The error in measurements of the width of the alveolar ridge at the place of the missing incisor was 0.33 mm, at the place of canine 0.25 mm. The error in measurements of distances was 0.51 mm, in measurements of the angle 4. The values were considered as appropriate for further measurements. Statistical processing The change of the toothless alveolar ridge at points A and B at periods T1, T2 and T3, was evaluated with the pair parameter t-test. The same evaluation was performed for the place of the canine alveolar ridge, and in the control group. The sign test was used to compare the change of the height of the alveolar ridge at the places of agenesis at the given periods of time. Student's t-test for two independent samples and correlation analysis was used for the analysis of the relationship between the distance of the canine from the central incisor at the beginning of the treatment (T1), for the amount of the bone created (T2) and its stability (T3A and T3B). Statistical significance of the relationship between the canine inclination at the beginning of the therapy (T1) and the amount of the bone formed (T2), and of the relationship of the canine inclination at T1 and the bone mass stability (T3) was evaluated by redakce@orthodont-cz.cz

7 Vy sledky AnalyÂza modeluê Testova nõâ kontrolnõâ skupiny. MeÏ rïenõâ zõâskanaâ z 25 sad modeluê vcï ase T1, T2 a T3 ukaâ zaly procentuaâ lnõâ zmeïnusïõârïky alveolu v bodeï A v mõâsteï zalozï eneâ ho lateraâ lnõâho rïezaâ ku nakonci leâcï by 1,5 % (T1-T2), 2 roky po leâcïbeï 2,5 % (T1-T3A) a5 let po leâcïbeï 2,0 % (T1-T3B). Procentua lnõâ zmeï na sï õârïky alveolu v bodeï B nakonci leâcï by byla1,4 % (T1-T2), 2 roky po leâcïbeï 1,9 % (T1- T3A) a5 let po leâcïbeï 0,4 % (T1-T3B). ZmeÏnasÏõÂrÏky alveolu Bezzuby prostor. ZmeÏ ny sï õârïky alveolaâ rnõâho hrïebene jsou uvedeny v tabulce cï. 1. Bylo zjisïteï no zmensï enõâ sïõârïky alveolu v mõâsteï ageneze o 4,0 % v bodeï A v obdobõâ T1-T2 adalsï õâ pokles o 1,6 % v obdobõâ 2 let po leâcïbeï (T2-T3A) a2,2 % v dobeï 5 let po leâcïbeï (T2-T3B) (Obr. 8). Celkova zmeï naod zahaâ jenõâ leâcï by (T1) do 2 let po leâcïbeï (T3A) byla0,58mm (SD 0,71) (p < 0,0001) neboli dosï lo k zmensï enõâ sï õârïky alveolu o 5,6 % v obdobõâ T1-T3A. Celkova zmeï naod zahaâ jenõâ leâcï by (T1) do 5 let po leâcï beï (T3B) byla0,61 mm (SD 0,76) (p < 0,0003) neboli 6,2 % zmensï enõâalveolaârnõâho hrïebene v obdobõâ T1-T3B. ZmensÏ enõâ sï õârïky alveolaâ rnõâho hrïebene v mõâsteï ageneze bylo 4,0 % v bodeï B v obdobõâ T1-T2 adalsï õâpokles o 2,2 % v obdobõâ 2 let po leâcïbeï (T2-T3A) a0,2 % v dobeï 5 let po leâcïbeï (T2-T3B) (Obr. 9). Celkova zmeï naod zahaâ jenõâ leâcï by (T1) do 2 let po leâcïbeï (T3A) byla0,83 mm (SD 0,97) (p < 0,0001) neboli 6,2 % ztraâ ty alveolaâ rnõâho hrïebene v obdobõâ T1-T3 A. Celkova zmeï naod zahaâ jenõâ leâcï by (T1) do 5 let po leâcï beï (T3B) byla0,35 mm (SD 0,63) (p < 0,0077) neboli 4,2 % ztraâ ty alveolaâ rnõâho hrïebene v obdobõâ T1-T3 B. Alveola rnõâ vyâbeï zïek u sï picï aâ ku. PruÊ meï rnaâ vestibulooraâ lnõâ sï õârïkaalveolaâ rnõâho vyâbeï zïku u sï picï aâ ku nazacï aâ tku the analysis of variance (ANOVA). We also evaluated - with the help of correlation analysis - the correlation of the canine inclination and its distance from the central incisor at the beginning of treatment and the amount of bone formed due to the canine distalization at the place of agenesis. Testing of significance was performed at 0.1 %, 1 % and 5 % level of significance (p < 0.001; 0.01; 0.05). Results Casts analysis Control group testing. Measurements obtained from 25 sets of casts at T1, T2 and T3 proved the change of width (in per cents) of the alveolus at the point A at the place of the lateral incisor at the end of treatment 1.5% (T1-T2), 2 years after treatment 2.5% (T1-T3A), and 5 years after treatment 2.0% (T1-T3B). The change of the alveolus width at the point B at the end of treatment was 1.4% (T1-T2), 2 years after treatment 1.9% (T1-T3A), and 5 years after treatment 0.4% (T1-T3B). Change in the alveolar width Toothles area. The values are given in Table 1. The width of the alveolus at the place of agenesis reduced by 4.0% at the point A at T1-T2, and further by 1.6 % in the period T2-T3A (2 years after treatment), and by 2.2 % at T2-T3B (5 years after treatment) (Fig. 8). The overall change since the beginning of treatment (T1) till 2 years after its completion (T3A) reached 0.58 mm (SD 0.71) (p < ); i.e. within the period T1-T3A the width of the alveolar ridge reduced by 5.6 %. The overall change since the beginning of treatment (T1) till 5 years after its completion (T3B) reached 0.61 mm (SD 0.76) (p < ); i.e. within the period T1-T3B the alveolar ridge reduced by 6.2 %. Obr.8.SÏ õârïka bezzubeâ ho alveolaâ rnõâho hrïebene v bodeï A v cï ase T1, T2, T3 Fig.8.Width of the toothless alveolar ridge at the point A at T1, T2,T3 Obr.9.SÏ õârïka bezzubeâ ho alveolaâ rnõâho hrïebene v bodeï B v cï ase T1, T2, T3 Fig.9.Width of the toothless alveolar ridge at the point B at T1, T2,T3 redakce@orthodont-cz.cz 17

8 ORTODONCIE Tabulka 1: ZmeÏnysÏõÂrÏky alveolaâ rnõâho hrïebene Table 1: Changes in the width of the alveolar ridge 10,2 10 9,8 9,6 9,4 9,2 9 8,8 8,6 8,4 Mean width of alveolus at the point A [mm] Before After treatment 2 years after treatment (T1) (T2) treatment (T3A) years after treatment (T3B) Distance C-I up to 1.5 mm Distance C-I more than 1.5 mm , ,6 11,4 11, ,8 10,6 10,4 10,2 10 Before treatment (T1) Mean width of alveolus at the point B [mm] After treatment (T2) years after treatment (T3A) years after treatment (T3B) Distance C-I up to 1.5 mm Distance C-I more than 1.5 mm Obr.10.ZmeÏ na sï õârïky bezzubeâ ho alveolaâ rnõâho hrïebene v bodeï AvcÏ ase T1,T2,T3 vzhledem ke vzdaâ lenosti sï picïaâ ku od strïednõâho rïezaâ ku na zacïaâ tku leâcïby Fig.10.The change of the toothless alveolar ridge at the point A at T1, T2, T3 in relation to the canine - central incisor distance at the beginning of the therapy Obr.11.ZmeÏ na sï õârïky bezzubeâ ho alveolaâ rnõâho hrïebene v bodeï B vcï ase T1,T2,T3 vzhledem ke vzdaâ lenosti sï picïaâ ku od strïednõâho rïezaâ ku na zacïaâ tku leâcïby Fig.11.The change of the toothless alveolar ridge at the point B at T1, T2, T3 in relation to the canine - central incisor distance at the beginning of the therapy leâcï by (T1) v bodeï A byla11,29mm (SD 0,75). Celkova zmeï naod zahaâ jenõâ leâcï by (T1) do 5 let po leâcïbeï (T3B) byla0,31mm (SD 0,52) (p < 0,004) neboli 2,8% ztraâty sïõârïky alveolu v obdobõâ T1-T3 B. PruÊ meï rnaâ vestibulooraâ lnõâ sï õârïkaalveolaâ rnõâho vyâbeïzïku sï picïaâ ku nazacïaâ tku leâcï by (T1) v bodeï B byla 13,26mm (SD 1,03). Celkova zmeï naod zahaâ jenõâ leâ cï by The width of the alveolar ridge at the place of agenesis reduced by 4.0% at the point B at T1-T2, and further by 2.2 % in the period T2-T3A (2 years after treatment), and by 0.2 % at T2-T3B (5 years after treatment) (Fig. 9). The overall change since the beginning of treatment (T1) till 2 years after its completion (T3A) reached 0.83 mm (SD 0.97) (p < ); i.e. within the period redakce@orthodont-cz.cz

9 Obr.12.PrÏi veïtsï õâ vzdaâ lenosti sï picïaâ ku od strïednõâho rïezaâ ku na zacï aâ tku leâ cï by je meâ neï kostnõâ masy Fig.12.With the increasing canine - central incisor distance at the beginning of treatment decreases the amount of bone. Tabulka.2: KorelacÏ nõâ analyâza - statisticky vyâznamnyâ pokles sïõârïky alveolu v cï ase T1 Table 2: Correlation analysis - statistically significant reduction of the alveolar ridge width at T1 (T1) do 5 let po leâcïbeï (T3B) byla0,31mm (SD 0,39) (p < 0,0003) neboli 2,4 % ztraâ ty alveolaâ rnõâho vyâbeïzïku v obdobõâ T1-T3 B. Vliv vzdaâ lenosti sï picïaâ ku od centraâ lnõâho rïezaâku Soubor pacientuê byl rozdeï len do dvou skupin ato podle vzdaâ lenosti sï picï aâ ku od strïednõâho rïezaâ ku. PrvnõÂ skupinu tvorïilo 77 agenetickyâ ch stran se vzdaâ lenostõâ sï picïaâ k - strïednõâ rïezaâ k do 1,5 mm, druhou skupinu tvorïilo 50 agenetickyâ ch stran se vzdaâ lenostõâ sï picï aâ k - strïednõâ rïezaâ k nad 1,5 mm. Hodnotilase statistickaâ zaâ vislost mezi vzdaâ lenostõâ sï picïaâ ku od strïednõâho rïezaâ ku nazacïaâ tku leâcï by amnozïstvõâm kosti, vytvorïeneâ distalizacõâ sï picï aâku prïi otevõâraânõâ mezery pro naâ hradu nezalozï eneâ ho lateraâ lnõâho rïezaâ ku (T1-T2), daâ le pak stabilita takto vytvorïeneâ kostnõâ masy (T2-T3A, T2-T3B). T1-T3A the width of the alveolar ridge reduced by 6.2 %. The overall change since the beginning of treatment (T1) till 5 years after its completion (T3B) reached 0.35 mm (SD 0.63) (p < ); i.e. within the period T1-T3B the alveolar ridge reduced by 4.2%. Alveolus of the canine. The mean vestibulooral width of the canine alveolar process at the beginning of treatment (T1) at the point A was mm (SD 0.75). The overall change since the beginning of treatment (T1) till 5 years after its completion (T3B) reached 0.31 mm (SD 0.52) (p < 0.004), i.e. 2.8 % loss of the alveolar width within T1-T3B. The mean vestibulooral width of the canine alveolar process at the beginning of treatment (T1) at the point B was mm (SD 1.03). The overall change since the beginning of treatment (T1) till 5 years after its completion (T3B) reached 0.31 mm (SD 0.39) (p < ), i.e. 2.4% loss of the alveolar process within T1-T3B. redakce@orthodont-cz.cz 19

10 ORTODONCIE DvouvyÂbeÏ rovyâ mi t-testy nebyly prokaâ zaâ ny ve sledovanyâ ch parametrech statisticky vyâ znamneâ rozdõâly mezi pacienty se vzdaâ lenostõâ sï picïaâ ku od strïednõâho rïezaâ ku do 1,5mm anad 1,5mm (Obr. 10 a11). KorelacÏ nõâ analyâ zou bylaprokaâ zaâ naslabaâ negativnõâ korelace mezi vzdaâ lenostõâ C-I prïed leâcï bou (T1) asï õârïkou bezzubeâ ho alveolaâ rnõâho hrïebene v bodeï B prïed leâ cï bou (T1) (viz Obr. 12, Tabulka cï. 2). Nebyl nalezen statisticky signifikantnõâ vztah mezi vzdaâ lenostõâ sï picï aâ ku od strïednõâho rïezaâ ku nazacï aâ tku leâcï by (T1) amezi mnozï stvõâm kosti nakonci leâcï by (T2) a stabilitou kostnõâ masy (T3). AnalyÂza ortopantomogramu Vliv sklonu sï picïaâku Soubor pacientuê byl rozdeï len do trïõâ skupin podle uâ hlu sï picïaâ ku k alveolaâ rnõâmu hrïebeni sï picïaâ ku. Prvnõ skupinu tvorïilo 43 agenetickyâ ch stran se sklonem sï picïaâkudo90 vcï ase T1, druhou skupinu tvorïilo 51 agenetickyâch stran se sklonem sï picïaâku vcïase T1 atrïetõâ skupinu tvorïilo 33 agenetickyâ ch stran se sklonem sï picïaâ ku nad 100 vcï ase T1. Hodnotilase statistickaâ zaâ vislost mezi sklonem sï picï aâ ku nazacï aâ tku leâ cï by amnozï stvõâm kosti, vytvorïeneâ distalizacõâ sï picï aâ ku prïi otevõâraâ nõâ mezery pro naâ hradu nezalozï eneâ ho lateraâ lnõâho rïezaâ ku (T1-T2), daâ le pak stabilitatakto vytvorïeneâ kostnõâ masy (T2-T3A, T2-T3B). Nebyly prokaâ zaâ ny statisticky vyâ znamneâ rozdõâly mezi vyâ sï e uvedenyâ mi skupinami a sledovanyâ mi parametry (Obr. 13, 14). Vztah mezi sklonem sï picïaâ ku nazacïaâ tku leâcï by (T1) amezi mnozï stvõâ kosti nakonci leâ cï by (T2) astabilitou kostnõâ masy (T3) nebyl nalezen. Nebylaproka zaâ na ani korelace vztahu vzdaâ lenosti sï picïaâ k - strïednõâ rïezaâk auâ hlu sï picïaâ ku k alveolaâ rnõâmu hrïebeni amnozïstvõâm kosti, kteraâ vznikne. 10,2 10,0 9,8 9,6 9,4 9,2 9,0 8,8 8,6 8,4 8,2 Mean width of alveolus at the point A [mm] Before treatment (T1) After treatment (T2) 2 years after treatment (T3A) years after treatment (T3B) Canine inclination up to 90 Canine inclination Canine inclination more than 100 Obr.13.ZmeÏ na sï õârïky bezzubeâ ho alveolaâ rnõâho hrïebene v bodeï AvcÏ ase T1,T2,T3 vzhledem ke sklonu sï picïaâ ku na zacïaâ tku leâcïby Fig.13.The change of the width of the toothless alveolar ridge at the point A at T1, T2, T3 with regard to the canine inclination at the beginning of treatment The impact of the distance between the canine and central incisor The sample of patients was divided into two groups according to the distance between the canine and central incisor. The first group involved 77 sides with agenesis, the canine - central incisor distance up to 1.5 mm, the second group involved 50 sides with agenesis, the canine - central incisor distance exceeded 1.5 mm. The statistical relationship between the canine - central incisor distance at the beginning of treatment and the amount of the bone created by the canine distalization during the opening of the space for the prosthetic treatment (T1-T2) was evaluated, as well as the stability of the bone mass thus created (T2-T3A, T2-T3B). Student's t-test for two independent samples did not prove statistically significant differences between the two groups (Fig. 10, 11). Correlation analysis proved a minor negative correlation between the neck C-I distance before the therapy (T1) and the width of the alveolar ridge at B before the therapy (T1) (see Fig. 12, Table 2). There was not found a statistically significant relationship between the canine - central incisor distance at the beginning of the therapy (T1) and the amount of bone at the end of the treatment (T2), and stability of the bone (T3). OPG analysis The impact of the canine inclination The sample of patients was divided into three groups according to the angle between the canine and the canine alveolar ridge. The first group involved 43 sides with agenesis with the canine inclination up to 90 at T1; the second group involved 51 sides with agenesis with the canine inclination between at T1; the third group involved 33 sides with agenesis with the canine inclination over 100 at T1. We evaluated statistical relationship between the canine inclination at the beginning of treatment and the amount of bone created through the canine distalization during the space opening (T1-T2), and the bone mass stability (T2-T3A, T2-T3B). Between the above given groups and the parameters monitored, no statistically significant differences were proved (Fig. 13, 14). There was found no relationship between the canine inclination at the beginning of treatment (T1) and the amount of bone at the end of treatment (T2), as well as the bone mass stability (T3). There was proved no correlation between the canine - central incisor distance and the angle between the canine and the alveolar ridge, and the amount of bone newly formed redakce@orthodont-cz.cz

11 11,8 11,6 11,4 11,2 11,0 10,8 10,6 10,4 10,2 Mean width of alveolus at the point B [mm] ZmeÏ na vyâ sï ky alveolaâ rnõâho hrïebene Jako referencï nõâ linie bylastanovenacementosklovinnaâ hranice zubuê sousedõâcõâch s mõâstem ageneze. Pokles vyâsï ky bezzubeâ ho alveolaâ rnõâho hrïebene byl 0,26 mm (SD 0,49) nakonci leâcï by (T1-T2), 0,41 mm (SD 0,65) 2 roky po leâcïbeï (T1-T3 A) a0,38 mm (SD 0,53) 5 let po leâcïbeï (T1-T3B). Diskuse Vy sledky teâ to studie potvrdily zmeï ny sï õârïky i vyâ sï ky a l- veolaâ rnõâho hrïebene, prïestavbu kosti i meï kkyâ ch tkaâ nõâ, jejich naâ slednou mõârnou atrofii v mõâsteï nezalozï eneâ ho hornõâho lateraâ lnõâho rïezaâ ku. Byl zjisï teï n pokles sï õârïky alveolu v mõâsteï ageneze v uâ rovni kostnõâho hrïebene o 4,0 % v obdobõât1 - T2 adalsï õâpokles o 1,6 % v obdobõâ 2 let po leâcïbeï (T2- T3 A) a2,2% v dobeï 5 let po leâcïbeï (T2-T3 B). Vestibuloora lnõâ sï õârïkameï rïenaâ 5 mm apikaâ lneï od hladiny kostnõâho hrïebene takeâ kleslao 4,0 % v obdobõâ T1 - T2, daâ le o 2,2 % v obdobõâ 2 let po leâcïbeï (T2- T3 A) a0,2 % v dobeï 5 let po leâcïbeï (T2-T3 B). Natoto teâ manebylo zatõâm publikovaâ no mnoho pracõâ. Ve studii, kteraâ zahrnovala dvacet pacientuê s agenezõâ lateraâ lnõâch rïezaâ kuê, Kokich nazubnõâch modelech atomografech pozoroval mnozï stvõâ zmeï n, ktereâ nastanou v bezzubeâ m hrïebeni [3]. MnozÏ stvõâ kostnõâ ztraâ ty bylo mensï õâ nezï 1 % od konce leâcïbyazï po dobu cï tyrï let po leâcïbeï. Tyto minimaâ lnõâ resorpcï nõâ zmeï ny alveolaâ rnõâho hrïebene byly prïipisovaâ ny praâ veï plaâ novaneâ mu vyâ voji implantovaneâ strany pomocõâ ortodontickeâ ho posunu zubu. V studii bylo zjisï teï no zmensï enõâ sï õârïky alveolaâ rnõâho vyâbeï zï ku pruê meï rneï o necelaâ 2 % v dobeï od ukoncï enõâ leâcïby azï po dobu peït let po leâcïbeï. Lze rïõâci, zïe kost vytvorïenaâ distalizacõâ sï picïaâku je dlouhodobeï stabilnõâ. Z vyâ sledkuê je patrneâ, zï e dvouprocentnõâ pokles sïõârïky kostnõâ masy alveolaâ rnõâho vyâbeïzïku po ukoncï enõâ leâcï by probõâhaâ, ale zmeï ny u skupiny meïrïeneâ po dvou letech au skupiny meï rïeneâ po peï ti letech byly jizï mi Before After treatment 2 years after treatment (T1) (T2) treatment (T3A) years after treatment (T3B) Canine inclination up to 90 Canine inclination Canine inclination more than 100 Obr.14.ZmeÏ na sï õârïky bezzubeâ ho alveolaâ rnõâho hrïebene v bodeï B vcï ase T1,T2,T3 vzhledem ke sklonu sï picïaâ ku na zacïaâ tku leâcïby Fig.14.The change of the width of the toothless alveolar ridge at the point B at T1, T2, T3 with regards to the canine inclination at the beginning of treatment- Change in the height of the alveolar ridge Cement-enamel junction (CEJ) of the teeth adjacent to the place of agenesis was taken as the reference line. The toothless alveolar ridge height decreased by O.26 mm (SD 0.49) at the end of treatment (T1-T2), by 0.41 mm (SD 0.65) 2 years after its completion (T1-T3A), and by 0.38 mm (SD 0.53) 5 years after its completion (T1-T3B). Discussion The results proved changes in width and height of the alveolar ridge, represented by the bone and soft tissues, at the place of the missing maxillary lateral incisor. The alveolus width at the place of agenesis on the level of bone ridge reduced by 4.0% at T1-T2, by 1.6% at T2-T3A, and by 2.2% at T2-T3B. The vestibulooral width measured 5 mm apically off the level of the bone ridge reduced by 4.0% at T1-T2, by 2.2% at T2- T3A, and by 0.2% at T2-T3B. There have not been published many studies on the topic. The study by Kokich [3] involved twenty patients with missing lateral incisor. With the help of casts and pantomographs, Kokich studies a number of changes occurring in the toothless alveolar ridge. The loss of bone mass was less than 1% since the end of treatment till four years after treatment. The minimum resorption changes of the alveolar ridge were attributed to the planned development of the implant side obtained by means of the orthodontic movement of the tooth. Kokich reports the reduction of the alveolar ridge width by less than 2% within the period from the end of the therapy till 5 years after its completion. Therefore, it is possible to state that the bone formed by the canine distalization is stable from the long-term viewpoint. The results suggest that the 2% reduction of the bone mass of the alveolar ridge width continues, however, the changes measured after two and five years were not significant. Even in the group measured five years after the completed treatment the toothless alveolus reduced at the point B only by 0.2%. Beyer [10] worked with the group of 14 patients with the total of 26 missing lateral incisors. She reported the loss of bone mass from 0.4% at the beginning of the therapy to 2.7% at its completion. The bone deficit kept increasing to 5.2% till the time of an implant introduction. However, she measured the overall surface of the alveolar ridge required for the implantation, not the vestibulooral distance. Therefore, she suggests that it is more appropriate to start the orthodontic treatment involving the canine distalization later. Beyer also states that the patients who started treatment later and reached the age of 16.5 years at the end of the treatment are closer to the time of implantation, and thus the period of the continual bone atrophy is shorter. Ho- redakce@orthodont-cz.cz 21

12 ORTODONCIE nimaâ lnõâ. Dokonce u skupiny meï rïeneâ po peï ti letech od konce leâ cï by dosï lo k zuâ zï enõâ bezzubeâ ho alveolu v bodeï B jen o 0,2 %. Beyerova ve sveâ studii, kteraâ zahrnovala 14 pacientuê s agenezõâ 26 lateraâ lnõâch rïezaâ kuê, zjistilaztraâ tu kostnõâ masy z pocïaâ tecï nõâho nedostatku 0,4 % prïi zahaâ jenõâ leâcï by na2,7 % nakonci leâcï by. Kostnõ deficit daâ le vzruê stal na 5,2 % do doby implantace [10]. Tato studie vsïakmeïrïila celkovyâ povrch alveolaâ rnõâho vyâbeï zï ku potrïebnyâ pro implantaci a ne vzdaâ lenost ve vestibulooraâ lnõâm smeï ru. Z tohoto pohledu plyne, zï e je vyâhodneâ zahaâ jit ortodontickou leâcï bu s distalizacõâ sï picïaâ ku pozdeï ji [10]. Beyerova daâle uvaâdõâ, zïe pacienti, kterïõâ zacï ali leâcï bu pozdeï ji adosaâ hli 16,5 let nakonci ortodontickeâ leâcï by, jsou blõâzïe cï asu implantace a perioda kontinuaâ lnõâ atrofie kosti je kratsï õâ. NasÏ e studie vsï ak ukazuje, zï e kost zõâskanaâ distalizacõâ sï picï aâ ku je stabilnõâ, a zuâ zï enõâ bezzubeâ ho alveolaâ rnõâho vyâbeï zï ku po peï ti letech od leâcï by pokracï uje jen minimaâ lneï, ato v individuaâlnõâch prïõâpadech, ve srovnaâ nõâ s meï rïenõâm sï õârïky alveolu dva roky po leâ cï beï.veï k pro zahaâ jenõâ ortodontickeâ ho otevõâraâ nõâ mezery pro naâ hradu nezalozï eneâ ho lateraâ lnõâho rïezaâ ku, dle teâ to studie, nenõâ prioritnõâ. VcÏ asneâ zahaâ jenõâ leâ cï by s ideaâ l- nõâm otevrïenõâm mezery ajejõâ provizornõâ naâ hrada adhezivnõâm muê stkem, do doby vhodneâ pro implantaci, je tedy jednou z mozïnostõâ. CÏ asneâ zahaâjenõâleâcïbyjeneï kdy i prïaânõâm pacienta a je duê lezïiteâ pro jeho psychiku. DrÏõÂveÏ jsï õâ studie ukazujõâ azï 34%zu zï enõâ alveolaâ rnõâho hrïebene po extrakci frontaâ lnõâch zubuê v hornõâ cï elisti [7]. Jina studie o agenezi dolnõâch druhyâ ch premolaâ ruê ukazuje, zïe sï õârïkaalveolaâ rnõâho hrïebene klesaâ o 25 % beï hem 3 let po extrakci docï asneâ ho molaâ ru [11]. Resorpce v naâ sledujõâcõâch cï tyrïech letech klesaâ na 4 %. Ve studii jsme se zameïrïili jen nahornõâ cï elist a oblast lateraâ lnõâch rïezaâkuê. Je teïzïkeâ porovnaâvatruê zneâ oblasti cïelisti s jinyâmi pomeï ry kosti aceâ vnõâho zaâ sobenõâ. Kokich posuzoval zmeï nysï õârïky alveolaâ rnõâho hrïebene i u zubuê sousedõâcõâch s mõâstem nezalozï enyâ ch dolnõâch druhyâ ch premolaâ ruê [11]. Zjistil, zï e u prvnõâho dolnõâho premolaâ ru dosïlokzuâzï enõâ hrïebene o 4 % v cï asoveâ periodeï od zahaâ jenõâ ortodontickeâ leâcï by do doby nejmeâ neï 6meÏsõÂcuÊ po ukoncï enõâ leâcï by. V nasï õâ studii takeâ zjisït'ujeme pokles sï õârïky alveolaâ rnõâho vyâbeï zïku sï picï aâ ku sousedõâcõâho s mõâstem ageneze, i zmeï nusï õârïky alveolaâ rnõâho hrïebene lateraâ lnõâho rïezaâ ku kontrolnõâ strany. Vy sledky ukazujõâ zuâ zï enõâ hrïebene v teï chto oblastech pruê meï rneï o 2,4 % v obdobõâ T1-T3 A(B). Je vsï ak nutneâ vzõât vuâ vahu, zï e 2,4 % prïedstavuje prïiblizïneï 0,34mm (SD 0,50) atudõâzï klinicky je tento uâ bytek nevyâznamnyâ. DuÊlezÏitou uâ rovnõâ, se kterou by se meï lo pracovat, je plaânovaânõâvyâvoje strany, kde bychom naâ sledneï v budoucnu chteï li zaveâ st implantaâ t. Po ztraâteï docï asneâ ho lateraâ lnõâho rïezaâ ku prorïezïe sï picï aâ k do tohoto prostoru. DocÏ asnyâ sï picïaâ k vede staâlyâsï picïaâkameï l by tedy byât extrahovaânteï sneï prïed posunem staâleâhosï picïaâ ku distaâ lneï, aby se zabraâ nilo prïedevsï õâm vestibulooraâ lnõâ atrofii alveolaâ rnõâ kosti. PrÏi diwever, our research proved that the bone, that is the result of the canine distalization, is stable, and the reduction of the toothless alveolar ridge is minimal in the period of 5 years after treatment, and moreover it is rather individual in comparison with the situation after 2 years. Our study suggests that the age does not play the crucial role in the decision when to start orthodontic space opening for the substitution of the missing lateral incisor. The early beginning of treatment together with the ideal opening of the space and the temporary substitution with adhesive bridge is one of the possible solutions. The early treatment may be in agreement with a patient's wish, and thus it is important for the good mental state of a patient. Previous works report 34% reduction of the alveolar ridge after the maxillary frontal teeth extraction [7]. Another study (dealing with the missing mandibular second premolars) reports that the width of the alveolar ridge reduces by 25% in the course of 3 years after the extraction of the temporary molar [11]. During the following 4 years the resorption reduces to 4%. In our study we focused on the maxilla and on the area of lateral incisors. It is difficult to compare different areas of jaws with different bone relations and different vascular system. Kokich [11] assessed the changes of the alveolar ridge width also in teeth adjacent to the place of missing lower second premolars. The alveolar ridge of the first lower premolar reduced by 4% within the period since the beginning of the therapy till 6 months after its completion. In our work, we also report the reduction of the width of the canine alveolar ridge adjacent to the place of agenesis, as well as the change in the width of the lateral incisor alveolar ridge on the control side. The results prove that the alveolar ridge reduced by 2.4% on average, at T1-T3 A (B). However, we have to take into account the fact that 2.4% correspond to 0.34 mm (SD 0.50), and thus, from the clinical viewpoint, the loss is virtually insignificant. It is important to plan the development of the side for the future implant. After the loss of a temporary lateral incisor, the canine erupts into the area. The temporary canine guides the permanent one, and therefore, it is advisable to extract it before the permanent canine moves distally. Thus we can prevent vestibulooral resorption of the alveolar bone. When the canine is moved distally, and the gap opens for the implant at the place of maxillary lateral incisor, the root of the canine forms appropriate amount of the alveolar process bone [8,12]. We found out, that the amount of the bone at the place of agenesis is significantly greater if the canine is located next to the central incisor. By distalization of the erupted canine, the bone should form along the width of the canine root. It may appear that the loss redakce@orthodont-cz.cz

13 staâ lnõâm posunu sï picï aâ ku aotevrïenõâ prostoru pro implantaât v mõâsteï hornõâho lateraâ lnõâho rïezaâ ku, vytvaârïõâ jeho korïen vyhovujõâcõâ mnozï stvõâ kosti alveolaâ rnõâho vyâbeï zï ku [8,12]. NasÏ e studie zjistila, zïe mnozïstvõâ kosti v mõâsteï ageneze na zacïaâ tku leâcï by je signifikantneï veïtsï õâ, pokud se sï picïaâ k nachaâ zõâ v bezprostrïednõâ blõâzkosti strïednõâho rïezaâ ku. Distalizacõ takto prorïezaneâho sï picï aâku by se meï lavytvorïit kost v rozsahu celeâ sïõârïky korïene sï picïaâ ku. Zda se, zï e rozsah ztraâ ty alveolaâ rnõâ kosti nastraneï implantaâ tu by meï l byât veïtsï õâ bez plaâ novaneâ ho vyâ voje implantovaneâ strany. Jak ale zlepsï it vyâ voj implantovaneâ strany vzhledem k zõâskaâ nõâ dostatecïneâ astabilnõâ kosti? VytvorÏilo by se snad võâce kosti, kdyby byl sï picï aâ k nejdrïõâve posunut ke strïednõâmu rïezaâ ku, s korïenem paralelneï ke korïeni rïezaâ ku, apoteâ bodily posunem distalizovaâ n pro otevrïenõâ prostoru pro naâ hradu lateraâ lnõâho rïezaâ ku? V nasï õâ studii jsme vsï ak tuto domneï nku nepotvrdili. Z vyâ sledkuê agrafickeâ ho znaâ zorneï nõâ je patrneâ, zï e mnozï stvõâ kosti nakonci leâ cï by v bodeï B je veï tsï õâ u skupiny se vzdaâ lenostõâ sï picïaâ k - strïednõâ rïezaâ k do 1,5mm. Statisticka vyâ znamnost vztahu mezi vzdaâ lenostõâ sï picï aâ ku od strïednõâho rïezaâ ku nazacï aâ tku leâ cï by a mnozï stvõâm kosti v mõâsteï ageneze na konci leâcïby vsï ak nebyla zjisïteï na. Ani na stabilitu kostnõâ masy nemeï lapolohasï picï aâku prïed leâcï bou vliv. Pouze, jak jizï bylo zmõâneïnovyâsï e, kdyzï jesï picïaâ k prorïezaâ n vedle strïednõâho rïezaâ ku, je mnozï stvõâ kosti v mõâsteï ageneze prïi zahaâ jenõâ leâ cï by signifikantneï veï tsï õâ, atõâm je situace pro vytvorïenõâ dostatecï neâ kosti prïõâzniveï jsï õâ. Nebyl nalezen ani vztah mezi mnozï stvõâ kosti v mõâsteï ageneze nakonci leâcï by asklonem sï picïaâku prïi zahaâ jenõâ leâcï by. PrÏi porovnaâ vaâ nõâ skupin podle sklonu sï picï aâ ku prïed leâ cï bou, dosï lo u skupiny s uâ hlem sï picïaâku k hrïebeni alveolu do 90 (paralelnõâ korïeny) k vytvorïenõâ veï tsï õâho mnozï stvõâ kosti v bodeï A nakonci leâ cï by. Statisticky vyâ znamnyâ rozdõâl mezi skupinami s ruê znyâ m sklonem sï picï aâ ku prïed leâ cï bou amnozï stvõâm vytvorïeneâ kosti ajejõâ stabilitou po leâ cï beï, vsï ak shledaâ n nebyl. Ani korelace vztahu vzdaâ lenosti asklonu sï picïaâ ku nazacïaâ tku leâcï by ajejich vliv namnozïstvõâ vytvorïeneâ kosti nebyl signifikantnõâ. VnasÏ õâ studii jsme hodnotili i zmeïnuvyâsï ky bezzubeâho alveolaâ rnõâho hrïebene v cï ase. OpeÏ t se ukaâ zalo, zï e vertikaâ lnõâ zmeï ny kosti, u skupiny meïrïeneâ po dvou apo peïti letech od ukoncï enõâ leâcï by, jsou jen minimaâ lnõâ, azï e kost vytvorïenaâ distalizacõâ sï picï aâ ku je stabilnõâ i ve vertikaâ lnõâm smeï ru. Kokich uvaâ dõâ pokles vyâsï ky alveolaâ rnõâho hrïebene v mõâsteï nezalozï enyâ ch dolnõâch druhyâ ch premolaâ ruê o 2% v cï asoveâ m intervalu T1-T3 [11]. Thilanderova ve sveâ studii uvaâ dõâ,zï e pokud je vzdaâ lenost mezi cementosklovinnou hranicõâ a alveolaâ rnõâm hrïebenem veï tsï õâ nezï 2 mm, je resorpce kosti prïõâtomna[13]. UpozornÏ uje naindividuaâ lnõâ variabilitu. NejveÏtsÏ õâ pokles vyâsï ky pozorovala v intervalu prïed zavedenõâm implantaâ tu a zï do jeho zatõâzï enõâ. PrÏed implantacõâ ve frontaâ lnõâ oblasti hornõâ cï elisti apo zatõâzï enõâ implantaâ tu byly ztraâ ty mensï õâ. Jejõ vyâsledky souhlasõâ s vyâsledky Espositovy studie [14]. of the alveolus bone at the side of the future implant is greater in case the development of the implantation side is not planned. How to improve the implant side development with regard to obtain sufficient and stable bone? Is it probable that in case the canine is first moved close to the central incisor, with their roots running parallel, and then distalized by the bodily movement (to open the gap for the implant), there will be greater amount of the bone created? Our research did not prove the assumption. The results and charts make it clear that the amount of bone at the point B the end of the therapy is greater in the group with the canine - central incisor distance up to 1.5 mm. However, the relation between the canine - central incisor distance at the beginning of the therapy and the amount of bone at the place of agenesis at the end of the therapy was not statistically significant. The position of the canine before treatment did not influence the bone mass stability either. In case the canine erupts next to the central incisor, the bone amount at the place of agenesis is significantly greater, and thus the situation is more favourable, as we have already mentioned above. The relationship between the amount of bone at the place of agenesis at the end of the therapy and the canine inclination at the beginning of the therapy was not proved. In the group of patients with the angle between the canine and the alveolar ridge up to 90 (parallel roots) there was greater amount of the bone mass at the point A at the end of the therapy. However, we did not prove statistically significant differences between the groups with different canine inclination before the therapy and the bone mass and its stability after treatment. In our study we evaluated the change in the toothless alveolar ridge height in time. Vertical changes of the bone, in the group assessed two and five years after the therapy, are trivial. The bone formed by the canine distalization is stable in the vertical direction, too. Kokich [11] reports that the alveolar ridge height at the place of missing lower second premolars decreased by 2% within T1-T3. Thilander [13] reports that if the distance between CEJ and the alveolar ridge exceeds 2 mm, there occurs resorption. However, she emphasized the individual variance. She recorded the most significant decrease of the height in the period between the implant insertion and its loading. Before the implantation in the maxillary frontal area and after the implant loading the loss was less significant. The results correspond to the results given by Esposito [14]. Conclusion The work evaluated changes in parameters of the alveolar ridge over the period of time in patients with missing maxillary lateral incisors: redakce@orthodont-cz.cz 23

14 ORTODONCIE ZaÂveÏr Ve studii byly posuzovaâ ny rozmeï roveâ zmeï ny alveolaâ rnõâho hrïebene v cï ase u pacientuê s agenezõâ hornõâch lateraâ lnõâch rïezaâkuê. Studie ukaâ zala: 1. SÏ õârïkaalveolaâ rnõâho vyâbeï zï ku v mõâsteï ageneze klesaâ o 4,0 % v bodeï A i B v obdobõâ od zahaâ jenõâ do ukoncï enõâ ortodontickeâ leâcï by (T1 - T2) 2. Kost vytvorïenaâ distalizacõâ sï picï aâ ku v mõâsteï nezalozï eneâ ho lateraâ lnõâho rïezaâ ku je pomeï rneï stabilnõâ. SÏ õârïka hrïebene v bodeï A pokleslav obdobõâ 2 let po leâcïbeï (T2- T3A) o 1,6 %, v dobeï 5 let po leâcïbeï (T2-T3B) o 2,2 %. SÏ õârïkahrïebene v bodeï B pokleslav obdobõâ 2 let po leâcïbeï (T2- T3A) o 2,2 %, v dobeï 5 let po leâcïbeï (T2-T3B) jen o 0,2 %, cozï je vzhledem k smeï rodatneâ odchylce (SD 0,63) zanedbatelneâ. 3. MnozÏstvõ kosti v mõâsteï ageneze na zacïaâ tku leâcïby je veïtsï õâ, pokud se sï picïaâ k nachaâ zõâ v bezprostrïednõâ blõâzkosti strïednõâho rïezaâ ku. Take mnozï stvõâ kosti nakonci leâcï by v bodeï B je veïtsï õâ u skupiny se vzdaâ lenostõâ sï picïaâk - strïednõâ rïezaâ k do 1,5 mm. Statisticka vyâ znamnost vztahu mezi vzdaâ lenostõâ sï picï aâ ku od strïednõâho rïezaâ ku nazacï aâ tku leâ cï by amnozï stvõâm kosti v mõâsteï ageneze nakonci leâcïbyvsï ak nebyla zjisïteïna. 4. Vzda lenost sï picïaâ ku od strïednõâho rïezaâkuprïedleâcïbou nemeï la na stabilitu kostnõâ masy vliv. MnozÏ stvõâ kosti v mõâsteï ageneze prïi zahaâ jenõâ leâ cï by je vsï a k veï tsï õâ, kdyzï sï picïaâ k prorïezï e vedle strïednõâho rïezaâ ku, atak je situace pro vytvorïenõâ dostatecïneâ kosti prïõâzniveïjsïõâ. 5. Vztah mezi sklonem sï picïaâku prïi zahaâ jenõâ leâcïby amnozï stvõâm kosti v mõâsteï ageneze na konci leâcï by nebyl nalezen. PrÏi porovnaâvaâ nõâ skupin podle sklonu sï picïaâku prïed leâcï bou, dosï lo u skupiny s uâ hlem sï picïaâku k hrïebeni alveolu do 90 (paralelnõâ korïeny) k vytvorïenõâ veï tsï õâho mnozï stvõâ kosti v mõâsteï bezzubeâ ho hrïebene v bodeï A. Statisticky vyâznamnyâ rozdõâl mezi skupinami sruê znyâm sklonem sï picïaâku prïed leâcï bou amnozï stvõâm kosti po leâcïbeïvsï ak shledaâ n nebyl. 6. Nebyl zjisïteï n vztah mezi sklonem sï picïaâ ku nazacïaâ tku leâcï by a stabilitou kostnõâ masy vytvorïeneâ distalizacõâ sï picïaâ ku. Da le nebylaprokaâ zaâ na korelace vztahu vzdaâ lenosti asklonu sï picïaâ ku nazacïaâ tku leâcï by ajejich vliv namnozïstvõâ vytvorïeneâ kosti. Z vyâ sledkuê vyplyâ vaâ urcï ityâ klinickyâ zaâ veï r. NejefektivneÏ jsï õâm zpuê sobem jak zajistit dostatecï neâ mnozï stvõâ kosti v mõâsteï otevõâraâ nõâ mezery pro naâ hradu chybeï jõâcõâho lateraâ lnõâho rïezaâ ku je: 1. individuaâ lnõâ vcï asnaâ extrakce docï asnyâ ch lateraâ l- nõâch rïezaâkuê 2. umozïneï nõâ prorïezaâ nõâ staâleâhosï picïaâ ku vedle strïednõâho rïezaâku 3. extrakce docï asneâ ho sï picï aâku teï sneï prïed zahaâ jenõâm ortodontickeâ leâcï by s distalizacõâ sï picïaâku 1. The width of the alveolar process at the place of agenesis reduces by 4.0% in both A and B within the period T1-T2 (beginning of the therapy and its completion). 2. The bone created by the distalization of the canine at the place of the missing lateral incisor is relatively stable. The alveolus width at the point A reduced by 1.6% at T2-T3A (two years after treatment), by 2.2% at T2-T3B (5 years). The alveolus width at the point B reduced by 2.2% at T2-T3A (two years after the therapy), by 0.2% at T2-T3B (5 years) which is - with regard to SD insignificant. 3. In case the canine is next to the central incisor, the amount of bone at the place of agenesis is greater. The amount of bone at the point B at the end of treatment is greater in the group with the canine - central incisor distance up to 1.5 mm. However, the relationship between the distance and the amount of bone is not statistically significant. 4. The distance between the canine and the central incisor before treatment did not influence the bone mass stability. However, there is more bone at the place of agenesis if the canine erupts next to the central incisor. 5. We did not prove any relationship between the canine inclination at the beginning of treatment and the amount of bone at the place of agenesis at the end of the therapy. In the group with the angle between the canine and the alveolar ridge up to 90 (parallel roots) more bone mass was created at the place of the toothless alveolar ridge at the point A. However, no statistically significant differences were found between the groups. 6. There was found no relationship between the canine inclination at the beginning of the therapy and the stability of the bone mass created by the canine distalization. No correlation between the canine distance and inclination at the beginning of the therapy and their impact on the amount of the bone created was found. The results suggest the conclusions for clinical practice. The most effective way to secure sufficient amount of the bone at the place of the space opening for the implant appears to be the following: 1. individual early extraction of deciduous lateral incisors 2. eruption of the permanent canine next to the central incisor 3. extraction of the deciduous canine just before the commencement of the orthodontic therapy involving the canine distalization redakce@orthodont-cz.cz

15 Literatura/References 1. Proffit, W. R.; Fields, H. W.: Contemporary orthodontics. 3th ed., St. Louis: Mosby, Kokich, V. G.: Managing orthodontic restorative treatment for the adolescent patient. In: McNamara,J. A.; Bruton,W. L.; Kokich,V. G.: Orthodontics and Dentofacial Orthopedics, Chapter 25. Ann Arbor, Michigan: Needham Press, 2001, s Kokich, G.: Maxillary lateral incisor implants: planning with the aid of orthodontics. J. Oral Maxillofac. Surg. 2004, 62, s Marek, I.; NovaÂcÏ kovaâ, S.: Ageneze lateraâ lnõâch rïezaâkuê. CÏ aâ st 1. Diagnostika a estetickeâ aspekty mezializace sï picïaâ ku. Ortodoncie. 2007, 16, cï. 2, s Marek, I.; NovaÂcÏ kovaâ, S.: Ageneze lateraâ lnõâch rïezaâkuê. CÏ aâ st 2. Ortodonticke aimplantologickeâ aspekty rïesï enõâ ageneze implantaâ tem. Ortodoncie. 2007, 16, cï. 3, s Marek, I.; NovaÂcÏ kovaâ, S.: Ageneze lateraâ lnõâch rïezaâkuê. CÏ aâst 3. RÏ esï enõâ adhezivnõâm muê stkem. Ortodoncie. 2007, 16, cï. 4, s Carlson, G.: Changes in contour of the maxillary alveolar process under immediate dentures. Acta Odontol. Scand. 1967, 25, s Spear, F. M.; Mathews, D. M.; Kokich, V. G.: Interdisciplinary management of single-tooth implants. Seminars in Orthodontics. 1997, 3, cï. 1, s Dahlberg, G.: Statistical methods for medical and biological students. London, Allen and Unwin Ltd, 1940, s Cit in: Ostler, M. S.; Kokich, V. G.: Alveolar ridge changes in patients congenitally missing second premolars. J. prosthet. Dent. 1997, 71, s Beyer, A.; Tausche, E.; Boening, K.; Harzer, W.: Orthodontic space opening in patients with congenitally missing lateral incisors. Angle Orthodont. 2007, 77, cï.3, s Ostler, M. S.; Kokich, V. G.: Alveolar ridge changes in patients congenitally missing second premolars. J. prosthet. Dent. 1997, 71, s Zachrisson, B. U.: Orthodontic tooth movement to regenerate new alveolar tissue and bone for improved single implant aesthetics.abstract. Eur. J. Orthodont. 2003, 25, cï. 4, s Thilander, B.; OÈ dman, J., et al.: Single implants in the upper incisor region and their relationship to the adjacent teeth. Clin. Oral Impl. Res. 1999, 10, s Esposito, M. A. B.; Ekestubbe, A.; GroÈ ndahl, K.: Radiological evaluation of marginal bone loss at tooth surface facing single BraÈ nemark implants. Clin. Oral Implant. Res. 1993, 4, s MUDr.SonÏ a Nova cï kovaâ Klinika zubnõâho leâ karïstvõâ LF UP Palacke ho 12, Olomouc ROD OSTRAVA SÏ kolenõâ pro ortodontisty: MUDr. Rene Folta n PhD. Brno - Hotel Myslivna ¹Temporomandibula rnõâ kloub v ortodonciiª Kurzy pro personaâ l - sestrïicï ky: MUDr. Marie SÏ tefkovaâ, CSc. TrÏinec - Hotel Steel ¹Ortodonticka diagnostika a leâcï ebneâ postupyª -I.cÏa st - teoretickyâ kurz MUDr. Marie SÏ tefkovaâ, CSc. TrÏinec ¹Ortodonticka diagnostika a leâcï ebneâ postupyª - II. cïaâ st - praktickyâ kurz Ze zahranicï nõâch akcõâ prïipravujeme: Portugal 2008 ± 84th Congress of the European Orthodontic Society Lisabon ± ve dnech 10.± ± vcï etneï doprovodnyâch akcõâ * * * Informace: ROD Ostrava ± BeÏ lovaâ Olga, MojmõÂrovcuÊ 799/45, Ostrava-Mar.Hory Tel.: , , obchod@rod-ostrava.cz redakce@orthodont-cz.cz 25