Retence premolaâruê Unerupted premolars

Transcription

1 rocïnõâk17 ORTODONCIE Retence premolaâruê Unerupted premolars MUDr.Hana BenesÏ ovaâ, MUDr.Magdalena Kot'ovaÂ, Ph.D. OddeÏ lenõâ ortodoncie a rozsïteï povyâch vad, stomatologickaâ klinika 3. LF UK, FN Kra lovskeâ Vinohrady Praha Department of Orthodontics and Cleft Defects, Clinic of Dental Medicine, 3rd Medical Faculty of Charles University, University Hospital Kra lovskeâ Vinohrady Prague Souhrn Sledovany soubor tvorïilo 75 pacientuê s retinovanyâ m premolaâ rem a kontrolnõâ soubor tvorïilo 80 pacientuê s fyziologickou vyâ meï nou chrupu. CõÂlem studie byla analyâ za znakuê vyskytujõâcõâch se v chrupu pacientuê s retencõâ/impaktacõâ premolaâruê. Na ortopantomogramech pacientuê jsme sledovaly odchylky erupcï nõâ draâ hy premolaâ ruê a porïadõâ prorïezaâ vaâ nõâ lateraâ lnõâch staâlyâ ch zubuê beï hem druheâ faâzevyâmeï ny chrupu. Na saâ drovyâ ch modelech jsme sledovaly ztraâ tu mõâsta v opeï rneâ zoâneï. DalsÏ õâmi znaky sledovanyâ mi v souvislosti s retencõâ premolaâruê byla ageneze jednoho z premolaâruê, prïõâtomnost nadpocï etnyâ ch zubuê v oblasti premolaâ ruê a reinkluze docï asnyâ ch molaâ ruê. SnazÏ ily jsme se urcï it nejcï asteï jsï õâ kombinace sledovanyâ ch znakuê, ktereâ se u retinovanyâ ch/impaktovanyâ ch premolaâ ruê vyskytovaly a z jejichzï manifestace by prïõâpadneï bylo mozïneâvcï as usuzovat na poruchy erupce premolaâruê. NejcÏ asteï ji retinovanyâ m zubem byl levyâ dolnõâ druhyâ premolaâ r, a nejcï asteï jsï õâ kombinacõâ znakuê, kteraâ se vyskytovala v chrupu pacientuê s retencõâ/impaktacõâ premolaâruê, byla ztraâ ta mõâsta v opeï rneâ zoâ neï a odchylka uâ hlu sklonu erupcï nõâ draâ hy premolaâ ru. Velmi pravdeï podobneï je tedy retence nebo impaktace premolaâ ruê vyâ sledkem võâce potenciaâ lneï patologickyâ ch jevuê a teprve jejich soucï asnyâ m vyâ skytem v daneâ oblasti dochaâ zõâ k retenci nebo impaktaci premolaâ ru(ortodoncie 2008, 17, cï. 3, s ). Abstract The sample involved 75 patients with an unerupted premolar; the control sample included 80 patients with physiological transition of dentition. The aim was to make the analysis of characteristic features in the dentition of patients with unerupted/impacted premolars. In panoramic X-ray pictures we observed deviations of the eruption paths of premolars, and sequence of eruption of lateral permanent teeth during the second phase of transition of dentition. In casts we observed the loss of space in the area. Further we observed agenesis of premolar, supernumerary teeth in the premolar area, submerged deciduous molars. We tried to establish the most frequent combinations of features observed in unerupted premolars, which may help in the early diagnosis of premolar eruption problems. The lower second premolar was the most frequent impacted tooth; the loss of space in the area together with deviation in the inclination of eruption path of premolar was the most frequent combination of characteristic features. It is highly probable, that unerupted or impacted premolars are the result of several potentially pathological phenomena, and that the uneruption and/or impaction occur only if these phenomena co-occur (Ortodoncie 2008, 17, No. 3, p ). KlõÂcÏ ovaâ slova: retence premolaâruê, impaktace Key Words: unerupted premolars, impaction redakce@orthodont-cz.cz

2 ORTODONCIE rocïnõâk17 U vod Retence zubu je tehdy, kdyzï zalozï enyâ zub neprorïezal ve fyziologickeâ mobdobõâ jeho prorïezaâvaâ nõâ a zub maâ ukoncï enyâ vyâvoj korïene. Na zev retence se vsïak uzïõâvaâ i v pruêbeï hu obdobõâ, kdy zub jesïteï m uêzïe fyziologicky prorïezat, ale jeho ulozïenõâ je tak anomaâ lnõâ, zï e mozïnost prorïezaâ nõâ do dutiny uâ stnõâ je velmi nepravdeï podobnaâ [2, 3]. Definice zadrzïeneâ erupce, cï i impaktace zubu je naâsledujõâcõâ: zub neprorïezal pro urcï itou prïekaâ zï ku, naprï. prïespocï etneâ zuby, cï i uzaâveï r prostoru sousednõâmi zuby [2]. Vy znampremolaâ ruê spocï õâvaâ, vedle jejich mastikacï nõâ funkce, v udrzïenõâ vyâsï ky skusu [1], podle jejich interkuspidace se diagnostikuje I. klõâcï okluze podle Andrewse [2]. Premola ry jsou z hlediska protetickeâ ho pilõârïe II. trïõâdy. Dojde-li ke sblokovaâ nõâ sousednõâch premolaâ ruê, lze je povazï ovat za protetickyâ pilõârï I. trïõâdy [1]. Nezanedbatelna je takeâ jejich uâ loha v oblasti estetiky tzv. bukaâlnõâch koridoruê [3, 4, 5, 6, 7, 8]. Sledova nõâmjednotlivyâ ch znakuê a kombinacõâ znakuê, ktereâ by mohly veâ st k retenci/impaktaci premolaâ ruê, jsme se snazï ily odhalit mozï nou prïõâcï inu retence/impaktace premolaâruê. ZajõÂmalo naâ s rovneï zï, zda lze vyâ voj neprïõâzniveâ situace prïi erupci premolaâruê ovlivnit ortodonticky. MateriaÂl NasÏ e pozorovaâ nõâ bylo provaâdeï no na souboru pacientuê s retencõâ/impaktacõâ premolaâruê (soubor B) a na souboru pacientuê s fyziologickou vyâmeï nou chrupu (soubor A). Soubor A (kontrolnõâ) zahrnoval 80 pacientuê s fyziologickyâ mpruê beï hemvyâ m eï ny chrupu, cozï bylo mozï no dokladovat na ortopantomogramech. Pro zarïazenõâ do kontrolnõâho souboru A byla stanovena naâ sledujõâcõâ kriteâ ria: 1. minimaâ lneï 3 na sebe navazujõâcõâ ortopantomogramy v dobeï vyâvoje a erupce premolaâruê, 2. prvnõâ rentgenovyâ snõâmek byl zhotoven po skoncï enõâ I. faâze vyâmeï ny chrupu, 3. zaâ rodky premolaâruê byly v odpovõâdajõâcõâmstadiu vyâ voje zubu a nachaâ zely se ve fyziologickeâ mpostavenõâ, 4. na dalsï õâch rentgenovyâ ch snõâmcõâch bylo mozï no prokaâ zat pokracï ujõâcõâ fyziologickyâ pruê beï h erupce premolaâruê. Soubor B (retence/impaktace premolaâruê ) zahrnoval 75 pacientuê, u kteryâch bylo mozïno dokladovat na saâdrovyâ ch modelech chrupu a na ortopantomogramech retenci/impaktaci premolaâ ru. Pro zarïazenõâ do sledovaneâ ho souboru B byla stanovena naâ sledujõâcõâ kriteâ ria : Introduction Unerupted tooth occurs when the germinated tooth did not erupt in the physiological phase of its eruption and its root development is finished. However, the termis used also for the period when a tooth may still erupt physiologically but its location is so abnormal that the potential eruption into the oral cavity is very improbable [2, 3]. The definition of arrested eruption, or impaction of a tooth, is the following: the tooth did not erupt due to some obstacle, e.g. supernumerary teeth, or closure of its eruption path by adjacent teeth [2]. Apart from mastication, premolars play an important role in maintaining the overbite [1], their occlusion serves in diagnostics of the 1st key of occlusion according to Andrews [2]. Fromthe prosthetic viewpoint, premolars serve as the prosthetic pillar of the 2nd grade. In case the adjacent premolars create a block, they may be considered a prosthetic pillar of the 1st grade [1]. They also play an important role in the esthetics of the so-called buccal corridors [3, 4, 5, 6, 7, 8]. We monitored individual features and their combinations that may result in uneruption/impaction of premolars, and thus we wanted to find out potential cause of premolars uneruption/impaction. We were also interested in whether the development of unfavorable situation may be affected with orthodontic treatment. Material We worked with the sample of patients with unerupted/impacted premolars (sample B), and with the sample of patients with physiological change of dentition (sample A). The sample A (control) included 80 patients with natural change of dentition (which was documented with panoramic X-ray pictures - OPG). The sample A met the following criteria: 1) minimum of 3 OPG taken during the development and eruption of premolars; 2) the first OPG was taken after the 1st phase of dentition change had been finished; 3) premolar teeth had normal stage of tooth development and their location was physiological; 4) following OPG proved the on-going physiological eruption of premolars. The sample B (unerupted/impacted premolars) included 75 patients in which unerupted/impacted premolars were found in casts and OPG. The sample B met the following criteria: 1) there exists at least one OPG for each patient; OPG may help in diagnostics of premolar uneruption and may help to identify that the development of the redakce@orthodont-cz.cz 23

3 rocïnõâk17 ORTODONCIE 1. pacient maâ zhotovenyâ minimaâ lneï jeden ortopantomogram, kde je mozï no diagnostikovat retenci premolaâ ru a urcï it, zïevyâvoj retinovaneâ ho zubu je, dle morfologie korïene skutecï neï ukoncï en, nebo, zï e se jednaâ o impaktaci, 2. pacient maâ zhotoven saâ drovyâ model chrupu soucï asneï s analyzovanyâ mrentgenovyâ m snõâmkem. Za duê lezï iteâ povazï ujeme upozorneï nõâ,zï e rentgenoveâ snõâmky nebyly zhotoveny pro uâcï ely teâ to studie. Metodika Na rentgenovyâ ch snõâmcõâch a saâ drovyâ ch modelech chrupu jsme sledovaly potenciaâ lneï patologickeâ znaky retence/impaktace premolaâruê (uâ hel sklonu erupcï nõâ draâ hy, ztraâ ta mõâsta v opeï rneâ zoâneï, porïadõâ erupce zubuê v lateraâ lnõâmuâ seku, ageneze premolaâruê, nadpocï etneâ zuby v oblasti remolaâruê, reinkluze docï asneâ ho molaâ ru). PrÏi pozorovaâ nõâ jednotlivyâ ch znakuê jsme sledovaly takeâ jejich kombinace. VyhodnocovaÂnõÂ erupcï nõâ draâ hy zaâ rodkuê premolaâruê (Obr. 1, 2) bylo provaâdeï no na ortopantomogramech. Byl meï rïen uâhel sklonu erupcï nõâdraâhy premolaâru vuê cï i okluznõâlinii, kteraâbyla urcï ena distaâlnõâm ruê zï kem dolnõâho centraâlnõâho rïezaâku a distaâlnõâm hrbolkem plneï prorïezaneâho prvnõâho staâleâho dolnõâho molaâru. PodeÂlnou osu zaârodku premolaâru tvorïila kolmice na spojnici dvou protilehlyâch boduê, ktereâse nachaâzely naproti sobeï v nejsï irsï õâm mõâsteï klinickeâkorunky. ProdlouzÏ enõâ konstruovaneâosy zaârodku premolaâru prïedstavovalo erupcï nõâdraâhu a protõânalo konstruovanou okluznõâ linii. UÂ hel erupcï nõâdraâhy premolaâru byl meï rïen k distaâlnõâmu konci okluznõâlinie. Na saâ drovyâch modelech chrupu pacientuê byla meïrïenõâmzjisït'ovaâna prïõâpadnaâ ztraâ ta mõâsta v opeï rneâ zoâ neï. Toto meï rïenõâbylo provaâdeï no standardnõâm zpuêsobem pomocõâposuvneâho meï rïidla. Pro zjisïteï nõâztraâty mõâsta v opeï rneâzoâneï byly pouzï ity zjednodusï eneâtabulky podle Moyerse k odhadu mõâsta potrïebneâho pro lateraâlnõâskupinu zubuê (staâleâ sï picïaâky a premolaâry). unerupted tooth is (according to the root morphology) finished, or that it is the case of impaction; 2) casts and analyzed OPG for each patient are present. We want to emphasize the fact that the OPG were not taken for the purpose of the presented study. Method In OPG and casts we observed potentially pathological features of uneruption/impaction of premolars (inclination of eruption path, loss of space for canines and premolars, sequence of teeth eruption in lateral segment, missing premolars, supernumerary teeth in the premolar area, submerged deciduous molar). We also paid attention to the combinations of individual factors. Evaluation of eruption path of premolar teeth (Fig. 1, 2) was made in OPG picture. We measured the inclination of premolar eruption path to the occlusal line. The occlusal line was determined by the distal corner of the lower central incisor, and distal cusp of the fully erupted first lower permanent molar. Long axis of the premolar germ was represented by the perpendicular to the connecting line of two opposite points located in the widest part of clinical crown. Prolongation of the constructed axis of the premolar represented eruption path and crossed constructed occlusal line. The angle of eruption path of premolar was measured with regard to the distal end of occlusal line. The potential loss of space in area of canines and premolars was measured in the casts. The measurement was performed with a calliper rule. Simplified version of Moyers tables was used to assess the loss of space in the area that is required for the group of lateral teeth (permanent canines and premolars). The sequence of teeth eruption in the lateral segment of dentition was assessed according to the position of tooth germs, or clinical crowns, in OPG. We focused especially on the eruption of second per- Obr.1: MeÏrÏenõÂuÂhlu erupcï nõâdraâhy - hornõâcï elist Fig.1: Measurement of eruption path angle - maxilla Obr.2: MeÏrÏenõÂuÂhlu erupcï nõâdraâhy - dolnõâcï elist Fig.2: Measurement of eruption path angle - mandible redakce@orthodont-cz.cz

4 ORTODONCIE rocïnõâk17 PorÏadõ erupce zubuê v lateraâ lnõâm uâ seku chrupu jsme hodnotily podle polohy zaârodkuê resp. klinickyâch korunek na ortopantomogramech pacientuê. V centru nasï eho zaâjmu byla zejmeâna erupce druheâho staâleâho molaâru, pokud nastala prïed erupcõâdruheâho premolaâru. SledovaÂnõ ageneze premolaâru bylo provaâdeïno opakovanyâm pozorovaânõâm na ortopantomogramech pacientuê. PrÏedmeÏ temnasï eho zaâ jmu se staly rovneïzï prïespocï etneâ zuby v oblasti premolaâ ruê, ktereâjsme pozorovaly na ortopantomogramech pacientuê. Vyhodnocenõ reinkluze docï asneâ ho molaâ ru bylo provaâdeï no pozorovaânõâm na ortopantomogramech pacientuê a na saâdrovyâch modelech chrupu. ZõÂskana data u jednotlivyâ ch souboruê byla zpracovaâ na oddeï leneï a vyhodnocena metodou popisneâ statistiky. Statisticke vyhodnocenõâ bylo provedeno StudentovyÂmt-testemrovnosti strïednõâch hodnot. Vy sledky Soubor A (kontrolnõâ) U kazïdeâ ho z 80 pacientuê v kontrolnõâmsouboru byly hodnoceny angulaâ rnõâ charakteristiky podeâ lneâ osy zaârodkuê vsï ech osmi premolaâruê vuê cï i konstruovaneâ okluznõâ linii. U kazïdeâ ho pacienta kontrolnõâho souboru bylo nameïrïeno 8 hodnot. ZõÂskaly jsme tak 640 nameïrïenyâch hodnot (n=640). Pro kazïdyâ premolaâ r byla stanovena strïednõâ hodnota (mediaâ n) vzestupneï serïazenyâ ch nameï rïenyâ ch hodnot uâ hluê jejich erupcï nõâ draâ hy. Takto zõâskanou hodnotu u kazï deâ ho premolaâ ru jsme povazï ovaly za ¹idea lnõâ uâ helª erupcï nõâdraâ hy pro sledovanyâ zub. Pro prïesneâ stanovenõâ ¹idea lnõâho uâ hluª erupcï nõâ draâ hy bylo pouzïito statistickeâ vyhodnocenõâ, jehozï vyâ sledky uvaâ dõâme v tabulce 1. Hodnotu ¹idea lnõâho uâ hluª jsme pouzïily k posouzenõâ uâ hlu sklonu erupcï nõâ draâhy zaâ rodkuê premolaâ ruê u souboru retinovanyâ ch/impaktovanyâ ch premolaâruê. Tato hodnota slouzï ila takeâ jako rozhranõâ pro stanovenõâ meziaâ lnõâho nebo distaâ lnõâho sklonu erupcï nõâ draâ hy premolaâ ruê v souboru retinovanyâ ch/impaktovanyâch premolaâruê. Pro dalsï õâ hodnocenõâ byla pouzï ita hodnota mediaâ nu uâ hlu erupcï nõâ draâ hy zjisïteïnaâ pro kazïdyâ premolaâ r zvlaâsït'. Tuto hodnotu lze povazï ovat za fyziologickou hodnotu uâ hlu erupcï nõâ draâ hy pro kazïdyâ jednotlivyâ premolaâ r (v Tabulce cï. 1 oznacï eno silneï). Soubor B (retence/impaktace premolaâruê ) U 75 pacientuê, kterïõâ splnï ovali stanovenaâ kriteria souboru B bylo nalezeno 108 retinovanyâ ch nebo impaktovanyâ ch premolaâ ruê (n=108). manent molar in case it preceded the eruption of second premolar. Missing premolar (agenesis) was assessed by repeated examination of OPG. We also paid attention to supernumerary teeth in the premolar area - we assessed the situation with the help of OPG. Submerged deciduous molar was assessed by examination of OPG and casts. The data obtained for individual samples of patients were processed separately, and evaluated with descriptive statistics. Statistic processing involved the t-tests. Results Sample A (control group) Inclination of long axes of the germs of all eight premolars to the constructed occlusal line was evaluated in 80 patients of the control group. For each patient 8 values were measured. The overall number was 640 (n=640). There was set the middle value (median) for each premolar - ascending sequence of the inclinations of their eruption paths. The middle value was taken as a ¹ideal inclinationª of the eruption path for the tooth observed. To state the ¹ideal inclinationª accurately, we use the statistical evaluation (the results are given in Table 1). The value of the ¹ideal inclinationª was used to assess the eruption path inclination of the germs of premolars in the group of impacted premolars. The value also served as the dividing line for setting of mesial or distal inclination of premolar eruption paths in the sample of impacted premolars. The median value of eruption path inclination set for each premolar separately was used. The value may be considered as the physiological inclination of eruption path for each individual premolar (in Table 1 in bold letters). Tabulka 1: StatistickeÂvyhodnocenõÂsledovanyÂch hodnot uâhlu erupcï nõâdraâhy kontrolnõâho souboru Table 1: Statistical evaluation of eruption path inclinations in the control group Tabulka 2: Skupiny souboru B. Znaky a kombinace znakuê v textu Table 2: Groups of sample B. Characteristic features and their combinations in text redakce@orthodont-cz.cz 25

5 rocïnõâk17 ORTODONCIE Sledovane znaky a jejich kombinace V souboru B byly zjisï teï ny naâ sledujõâcõâ znaky a jejich kombinace vytvorïily naâ sledujõâcõâ skupiny B1 - B9 (pocï ty zubuê ve skupinaâ ch v tabulce 2): B1 ZtraÂta mõâsta v opeï rneâzoâneï a odchylka uâhlu sklonu retinovaneâho premolaâru B2 ZtraÂta mõâsta v opeï rneâzoâneï, odchylka uâhlu sklonu retinovaneâho premolaâru a erupce druheâho staâleâho molaâru prïed druhyâm premolaârem B3 Odchylka uâhlu sklonu retinovaneâho premolaâru, ageneze sousednõâho nebo druhostranneâho premolaâru a ztraâta mõâsta v opeï rneâzoâneï B4 ZtraÂta mõâsta v opeï rneâzoâneï a odchylka uâhlu sklonu retinovaneâho premolaâru a reinkluze docï asneâho molaâru B5 Erupce druheâho staâleâho molaâru prïed druhyâm premolaârem a odchylka uâhlu sklonu retinovaneâho premolaâru B6 Odchylka uâhlu sklonu retinovaneâho premolaâru B7 Odchylka uâhlu sklonu retinovaneâho premolaâru a reinkluze docï asneâho molaâru B8 Odchylka uâhlu sklonu retinovaneâho premolaâru, erupce druheâho staâleâho molaâru prïed druhyâm premolaârem a reinkluze B9 Odchylka uâhlu sklonu retinovaneâho premolaâru, ageneze sousednõâho nebo druhostranneâho premolaâru, ztraâta opeï rneâzoâny a erupce druheâho staâleâho molaâru prïed druhyâm premolaârem. PrÏi zpracovaânõâvyâsledkuê nameïrïenyâch hodnot u jednotlivyâch skupin B1 - B9 jsme vyhodnocovaly uâ daje oddeï leneï pro kazï dou cï elist pacienta. U pacientuê souboru B jsme roztrïõâdily nameï rïeneâ uâ hly erupcï nõâ draâ hy jednotlivyâ ch premolaâ ruê podle jejich inklinace. Za rozhranõâ jsme povazï ovaly strïednõâ hodnotu (median) uâ hlu erupcï nõâ draâ hy zjisïteï nou pro jednotliveâ premolaâ ry v kontrolnõâmsouboru (soubor A). U hly s hodnotou nizïsïõânezï je strïednõâhodnota uâhlu erupcï nõâdraâhy zjisïteï naâv kontrolnõâm souboru jsme daâle povazï ovaly za uâhly sveï dcï õâcõâ o meziaâ lnõâm sklonu erupcï nõâdraâhy. U hly s hodnotou vysïsïõânezï je strïednõâhodnota uâhlu erupcï nõâdraâhy zjisïteï naâv kontrolnõâm souboru jsme daâle povazï ovaly za uâhly sveï dcï õâcõâ o distaâ lnõâm sklonu erupcï nõâdraâhy. Za kladnõâ vyhodnocenõâ souboru B Ze 75 pacientuê souboru B meï lo 49 pacientuê (65 %) jen jeden retinovanyâ/impaktovanyâ premolaâ r, u 22 pacientuê (29 %) jsme nalezly dva retinovaneâ /impaktovaneâ premolaâ ry. TrÏi retinovaneâ premolaâ ry byly u 2 pacientuê,daâ le byly registrovaânycï tyrïi (1 pacient) a peï t retinovanyâch premolaâruê (1 pacient). Retence/impaktace jednoho premolaâ ru se u pacientuê v souboru B vyskytovala dvakraâtcï asteï ji v dolnõâ cï elisti nezï v hornõâ cï elisti. Sample B (unerupted/impacted premolars) In 75 patients included in the sample B, there were 108 unerupted or impacted premolars (n=108). The features monitored, their combinations In the sample B the following features and their combinations were found and the following groups B1 - B9 were formed (number of teeth in groups are in Table 2): B1 Loss of space in area of canine and premolars, and deviation in inclination of unerupted premolar. B2 Loss of space in area of canine and premolars, deviation in inclination of unerupted premolar, and eruption of the second permanent molar preceding the second premolar. B3 Deviation in the inclination of unerupted premolar, missing neighbouring or opposite premolar, and the loss of space in area of canine and premolars. B4 Loss of space in area of canine and premolars, deviation in inclination of unerupted premolar, and submerged deciduous molar. B5 Eruption of the second permanent molar precedes that of the second premolar, and deviation in inclination of unerupted premolar. B6 Deviation in inclination of unerupted premolar. B7 Deviation in inclination of unerupted premolar, and submerged deciduous molar. B8 Deviation in inclination of unerupted premolar, eruption of the second permanent molar preceding that of the second premolar, and submergence. B9 Deviation in inclination of unerupted premolar, agenesis of the neighbouring or opposite premolar, loss of space in area of canine and premolars, and eruption of the second permanent molar preceding that of the second premolar. The results were processed for each group (B1-B9) and each jaw separately. The eruption path angles of individual premolars were classified according to their inclination. The borderline was the median of eruption path angle of individual premolars in the control sample (group A). Angles below the middle value of the eruption path angle found in the control sample, manifest mesial inclination of eruption path. Angles over the middle value of the eruption path angle found in the control sample, manifest distal inclination of eruption path. Basic evaluation of the sample B From the sample B (75 patients) one unerupted/impacted premolar was found in 49 (65 %) of them. 22 patients (29 %) had two unerupted/impacted premolars, three unerupted premolars were in 2 patients. There were registered also 4 (1 patient) and 5 (1 patient) unerupted premolars redakce@orthodont-cz.cz

6 ORTODONCIE rocïnõâk17 Obr.3.RozdeÏ lenõâpacientuê podle pocï tu retinovanyâch/impaktovanyâch premolaâruê (soubor B) Fig.3.Patients according to the number of unerupted/impacted premolars (sample B) ZhodnocenõÂmsouboru pacientuê s retinovanyâ mi/impaktovanyâ mi premolaâ ry bylo zjisï teï no, zï e nejcï asteï ji retinovanyâ/impaktovanyâ premolaâ r byl zub 35 (38%) naâsledovanyâ zubem45 (28,7%). V premolaâ roveâ oblasti hornõâ cï elisti dosï lo nejcï asteï ji k retenci/impaktaci zubu 25 (14,8%). Vyhodnocenõ znakuê a jejich kombinacõâ v souboru B Z celkoveâ ho pocï tu vyhodnocovanyâ ch znakuê a jejich kombinacõâ (n=108) bylo nejvõâce (44,4%) zarïazeno do skupiny B1 (ztraâ ta mõâsta v opeï rneâ zoâneï a odchylka uâ hlu sklonu erupcï nõâ draâ hy premolaâ ru). Druhou vyâ znamnou skupinu znakuê prïedstavovala skupina oznacï enaâ B2 (vyâ skyt ztraâ ty mõâsta v opeï rneâ zoâ neï, odchylka uâ hlu sklonu erupcï nõâ draâ hy premolaâ ru a erupce druheâ ho staâleâ ho molaâ ru prïed druhyâ mpremolaâ rem) jejõâzï podõâl byl 35,2 % souboru (Tab. 2). U skupin B4 - B9 je pocï et znakuê v kazïdeâ skupineï mensï õâ nebo roven trïem(n 3). Z tohoto duê vodu jsme v dalsï õâmzpracovaâ nõâ tyto skupiny v souboru B samostatneï nevyhodnocovaly, ale jsou zastoupeny v hodnocenõâ jevuê u jednotlivyâ ch premolaâ ruê. Analy za skupin znakuê a kombinacõâ znakuê v souboru B Skupina B1 Do teâ to skupiny pacientuê seztraâ tou mõâsta v opeï rneâ zoâneï a odchylkou uâ hlu sklonu erupcï nõâ draâ hy premolaâ ru (B1) bylo zarïazeno 48 retinovanyâch/impaktovanyâch zubuê. NameÏ rïeneâhodnoty uâhluê erupcï nõâdraâhy retinovanyâch/impaktovanyâch premolaâruê vykazujõâvelkou variabilitu. Lze rïõâci, zï e retinovaneâpremolaâry v teâto skupineï vyârazneï cï asteï ji dosahovaly meziaâlnõâho sklonu. V teâ to skupineï B1 byl nejcï asteï ji retinovanyâ/impaktovanyâ zub 35 a vykazoval meziaâ lnõâ sklon erupcï nõâ draâ hy. V hornõâ cï elisti byl v nasï empodsouboru cï asteï ji retinovanyâ/impaktovanyâ zub 25 a takeâ byl meziaâ lneï skloneï n. Obr.4.CÏ etnost retencõâ/impaktacõâ u jednotlivyâch premolaâruê - soubor B Fig.4.Number of unerupted/impacted teeth in individual premolars - sample B In sample B the unerupted/impacted one premolar in the mandible was two times more frequent than that in maxilla. The most frequent unerupted/impacted premolars were (in order of prevalence): the tooth 35 (38 %) and the tooth 45 (28.7 %). In the premolar area of the maxilla the tooth 25 was the most often unerupted/impacted one (14.8 %). Evaluation of features and their combinations in the sample B Within the total number of characteristic features evaluated, including their combinations (n=108), the group B1 prevailed (44.4 %), i.e. loss of space in area of canine and premolars and deviation of the premolar eruption path inclination. The group B2 (loss of space in the area, deviation of premolar eruption path inclination, and eruption of second permanent molar preceding that of the second premolar) represented 35.2 % (Table 2). In groups B4-B9 the number of features is three or below three (n 3). Therefore, these groups of the sample B were not evaluated separately. However, they are included in the evaluation of the phenomena in individual premolars. Analysis of the features and their combinations in the sample B Group B1 48 unerupted/impacted teeth were included in this group of patients with loss of space in area of canine and premolars and deviation of premolar eruption path inclination (B1). The values of angles of eruption path of unerupted/impacted premolars show great variability. Unerupted/impacted premolars inclined mesially most frequently. redakce@orthodont-cz.cz 27

7 rocïnõâk17 ORTODONCIE Tab.3: ZtraÂta mõâsta a odchylka erupcï nõâdraâhy premolaâru - skupina B1 Table 3: Lost space and deviation of eruption path of premolar - group B1 Tabulka 4: Erupce druheâho staâleâho molaâru prïed druhyâm premolaârem - skupina B2 Table 4: Eruption of second permanent molar before the second premolar - group B2 Tabulka 5: Ageneze, ztraâta mõâsta a odchylka erupcï nõâdraâhy - skupina B3 Table 5: Agenesis, lost space a deviation of eruption path - group B3 K nejveïtsï õâztraâteï mõâsta v opeï rneâ zoâneï dosï lo v kvadrantu 3, kde hodnota maxima cï inila 9,2 mm a pocïetprïõâpaduê vyâskytu ztraâ ty mõâsta v opeï rneâ zoâ neï byl rovneï zï nejvysï sï õâ v tomto kvadrantu. PruÊmeÏ rnaâ hodnota ztraâ ty opeï rneâ zoâny uvsï ech kvadrantuê se pohybovala okolo 5 mm. Skupina B2 Ve skupineï pacientuê se ztraâ tou mõâsta v opeï rneâ zoâneï, odchylkou uâ hlu sklonu erupcï nõâ draâ hy premolaâ ru a erupcõâ druheâ ho staâleâ ho molaâruprïed druhyâm premolaâ rem (B2) jsme sledovaly 38 prïõâpaduê retinovanyâch/impaktovanyâch premolaâruê. Znaky skupiny B2 se nejcï asteï ji vyskytovaly v dolnõâm zubnõâmoblouku. V hornõâmzubnõâmoblouku byl zaznamenaâ n pouze jeden vyâskyt v kvadrantu 2, kvadrant 1 nebyl zastoupen vuê bec. NejveÏtsÏõÂvyÂskyt byl zaznamenaâ n v kvadrantu 3. Maximum ztraâ ty mõâsta v opeï rneâ zoâneï bylo nameïrïeno v dolnõâmzubnõâmoblouku a cï inilo 7,1 resp. 7,2 mm. Skupina B3 Do skupiny pacientuê s odchylkou uâ hlu sklonu erupcï nõâ draâ hy premolaâ ru, agenezõâ sousednõâho nebo druhostranneâ ho premolaâ ru a ztraâ tou mõâsta v opeï rneâ zoâ neï (B3) bylo zarïazeno 9 prïõâpaduê retinovanyâch/impaktovanyâch premolaâruê. Kombinace znakuê teâ to skupiny se vyskytla nejcï a- steï ji v kvadrantu 2. Ve trïech prïõâpadech ageneze nebyl zalozï enyâ premolaâ r, kteryâ by sousedil s premolaâ remretinovanyâ m/impaktovanyâm.cï asteï ji jsme vsï ak nalezly prïõâpady retinovaneâ ho/impaktovaneâ ho premolaâ ru spojeneâ s agenezõâ protilehleâ ho premolaâ ru daneâ cï elisti. U dvou trïetin pacientuê ze skupiny B3 se vyskytla ageneze jednoho premolaâ ru a retence/impaktace druhostranneâ ho premolaâ ru. V jednomprïõâpadeï retinovaneâ ho zubu 25 se druhostranneï vyskytla nejen ageneze druheâ ho premolaâ ru, ale takeâ transpozice staâ leâ hosï picï aâ ku a prvnõâho premolaâ ru. PrÏedcÏ asnaâ ztraâ ta mõâsta v opeï rneâ zoâneï postihla vyârazneï ji hornõâ zubnõâ oblouk. The prevailing unerupted/impacted tooth in the group B1 was 35. The tooth also showed mesial inclination of its eruption path. In the group, the most frequent unerupted/impacted tooth in the maxilla was 25. The tooth also inclined mesially. The greatest loss of space in area was found in the quadrant 3, with the maximum value of 9.2 mm. The loss of space in area of canine and premolars was also most frequently found in this quadrant. The mean value of the loss of space reached approximately 5 mm. Group B2 38 unerupted/impacted teeth were included in this group of patients with loss of space in area of canine and premolars, deviation of premolar eruption path, and the eruption of second permanent molar preceding that of second premolar (B2). Characteristic features for B2 were found especially in the lower dental arch. We recorded only one in the upper dental arch, quadrant 2; there were no features recorded in quadrant 1. The highest incidence was recorded in quadrant 3. The maximum loss of space in area of canine and premolars was measured in the lower dental arch mm, 7.2 mm respectively. Group B3 9 unerupted/impacted premolars were included in this group of patients with deviation of premolar eruption path, loss of adjacent or opposite premolar, and loss of space in area of canine and premolars (B3). The highest incidence of combinations of characteristic features was found in quadrant redakce@orthodont-cz.cz

8 ORTODONCIE rocïnõâk17 Sklon erupcï nõâ draâ hy u retinovaneâ ho/ impaktovaneâ ho premolaâ ru vykazuje v prïõâpadeï zubuê 24, 25 a 35 meziaâ lnõâ tendenci, u premolaâruê 14 a 44 naleâzaâ me distaâ lnõâ sklon. NejcÏ asteï ji retinovanyâ mi/impaktovanyâ mi zuby souboru B byly dolnõâ druheâ premolaâ ry, proto jsme u teï chto prïõâpaduê vyhodnotily znaky (skupiny znakuê ), ktereâ se podõâlely na vzniku retence zubuê 35 a 45. Retence/impaktace dolnõâch premolaâruê Retence/impaktace leveâ ho dolnõâho druheâ ho premolaâru prïedstavovala v souboru B nejcï asteï ji se vyskytujõâcõâ retinovanyâzub (41 prïõâpaduê ). Na retenci/impaktaci zde participovalo 7 skupin znakuê, z nichzï 50% zaujõâmala kombinace znakuê - ztraâta mõâsta v opeï rneâ zoâneï, odchylka uâhlu sklonu erupcï nõâdraâhy premolaâru a erupce druheâho staâleâho molaâru prïed druhyâm premolaârem. DruhaÂnejcÏ asteï ji zastoupenaâkombinace znakuê (29%) byla ztraâta mõâsta v opeï rneâzoâneï a odchylka uâhlu sklonu erupcï nõâdraâhy premolaâru. Z dalsï õâch pozorovanyâ ch znakuê se ve trïech prïõâpadech objevila reinkluze docï asneâhoprïedchuê dce a v peï ti prïõâpadech se prïidruzïila ageneze protilehleâ ho zubu 45. Ztra ta opeï rneâ zoânycï inila pruêmeï rneï 4,54 mm. Sklon erupcï nõâ draâ hy vykazoval prïevahu meziaâ lneï skloneï nyâch retinovanyâ ch/impaktovanyâ ch premolaâ ruê (58,54% prïõâpaduê ). NameÏ rïeneâ angulaâ rnõâ parametry vykazovaly velkyâ rozsah mezi minimaâ lnõâm a maximaâ lnõâmuâ hlem sklonu erupcï nõâ draâ hy. Druha nejpocï etneï jsï õâ skupina retinovanyâ ch/impaktovanyâ ch premolaâ ruê prïipadala na zub 45 (31 pacientuê ). Na patologickeâerupcï nõâsituaci se zde podõâlelo 6 skupin znakuê, nadpolovicïnõâveïtsï ina (56%) prïipadala na kombinaci znakuê - ztraâta mõâsta v opeï rneâzoâneï, odchylka uâhlu sklonu erupcï nõâdraâhy premolaâru a erupce druheâho staâleâho molaâru prïed druhyâm premolaârem. Ve 32% prïõâpaduê byla pozorovaâ na kombinace ztraâty mõâsta v opeï rneâ zoâneï a odchylky uâ hlu sklonu erupcïnõâ draâ hy premolaâ ru. Hodnota pruêmeï rneâ ztraâ ty mõâsta v opeï rneâ zoâneïcï inila 4,34 mm. PrÏi sledovaâ nõâ soucï asneâ ho vyâ skytu ageneze a ztraâ ty mõâsta byl nalezen pouze jeden pacient s nezalozï enyâ mprotilehlyâ mpremolaâ rem. Hodnoty uâ hlu erupcï nõâ draâ hy ukazujõâ na velmi vyrovnanou tendenci k meziaâ lnõâmu i distaâ lnõâmu sklonu retinovaneâ ho/impaktovaneâ ho premolaâ ru 45. U hel sklonu erupcï nõâ draâ hy premolaâ ruê jevil nejvõâce nepravidelnostõâ u zubuê 35 a 45. Pro statistickeâ vyhodnocenõâ byl proveden vyâbeïrze vsï ech nameï rïenyâ ch hodnot uâ hlu sklonu erupcï nõâ draâ hy zubuê 35 a 45 u kontrolnõâho souboru a u souboru B. Pa rovyâ mt-testemrovnosti strïednõâch hodnot bylo zjisïteï no, zïe rozdõâl pruêmeï rneâho uâ hlu sklonu erupcïnõâ Three cases of agenesis were represented by the absence of premolar that would neighbour with the unerupted premolar. However, the unerupted premolar accompanied with the loss of the opposite premolar was more frequent. In 2/3 of patients in group B3 the agenesis of one premolar together with unerupted opposite premolar was found. In one unereupted tooth 25 there occurred agenesis of the second premolar together with the transposition of permanent canine and first premolar. The early loss of space in area of canine and premolars affected more often the upper dental arch. Inclination of the eruption path of the unerupted/impacted premolar shows mesial tendency in case of teeth 24, 25 and 35, while distal inclination is found in premolars 14 and 44. Lower second premolars were the most frequently unerupted/impacted teeth in group B. Therefore, in these cases we evaluated features (or groups of features) contributing to the uneruption of the teeth 35 and 45. Unerupted/impacted lower premolars Unerupted/impacted left lower second premolar represented the most frequently unerupted tooth in group B (41 patients). 7 groups of features contributed to the uneruption/impaction; 50% represented combination of the features - loss of space in area of canine and premolars, deviation of the eruption path of premolar, and eruption of second permanent molar preceding that of second premolar. The second most frequent combination of features (29%) included loss of space in the area, and deviation of the inclination of the eruption path of premolar. We should also mention three cases of submerged deciduous tooth, and five cases with agenesis of the opposite tooth 45. The average loss of area of canine and premolars was 4.54 mm. Inclination of eruption path was mostly represented by mesially inclined unerupted/impacted premolars (58.54%). Angular parameters showed great range between the maximum and minimum angle of inclination of the eruption path. The second most frequent group of unerupted/ impacted premolars was represented by the tooth 45 (31 patients). 6 groups of features contributed to the abnormal eruption. 56% represented combination - loss of space in area of canine and premolars, deviation of premolar eruption path, and eruption of second permanent molar preceding that of second premolar. The average loss of space in the area of canine and premolars was 4.34 mm. Only one patient with agenesis of opposite premolar was recorded. Angular parameters show balanced tendency to both mesial and di- redakce@orthodont-cz.cz 29

9 rocïnõâk17 ORTODONCIE Obr.5.Retence/impaktace 35 - kombinace znakuê Fig.5.Unerupted/impacted 35 - features draâ hy souboru B a kontrolnõâho souboru je statisticky nevyâznamnyâ na hladineï vyâznamnosti 5% (p 0,5). U hel sklonu erupcï nõâ draâ hy sledovanyâ ve skupinaâ ch souboru B (retence/impaktace premolaâ ru) vykazoval v hornõâ cï elisti tendenci k distaâ lnõâmu sklonu erupcï nõâ draâ hy, pro dolnõâ cï elist byl pomeï r tendence k meziaâlnõâmu nebo distaâ lnõâmu sklonu 1:1. Diskuse Problematikou uâ hlu sklonu erupcï nõâ draâ hy premolaâ ru se zabyâ val ve sveâ studii Wasserstein v Izraeli v roce 2002, kdyzï m eï rïil na ortopantomogramech angulaâ rnõâ parametry druheâ ho dolnõâho premolaâru u 85 deï tõâ s prïedcï asnou ztraâ tou docï asneâ ho druheâ ho molaâ ru. V teâ to studii zjistil, zï e po prïedcï asneâ ztraâteï dolnõâho docï asneâ ho druheâho molaâ ru druhyâ dolnõâ premolaâ r vykazuje veï tsï õâ variabilitu vuâ hlu sklonu sveâ erupcï nõâ draâ hy, ale tento rozdõâl oproti kontrolnõâ skupineï nenõâ statisticky vyâ znamnyâ (pacienti s prïedcï asnou ztraâ tou - druhyâ dolnõâ premolaâ r prorïezaâ val pod uâ hlem79,6, u pacientuê, kde nedosïlokprïedcï asneâ ztraâteï druheâ ho dolnõâho docï asneâ ho molaâ ru - druheâ dolnõâ premolaâ ry prorïezaâ valy pod uâ hlem83,2 ) [10]. Media n uâ hlu erupcï nõâ draâ hy v kontrolnõâ skupineï nasï eho souboru pro zuby 35 a 45 cï inil 87 (tedy rozdõâl 3,8 oproti WassesteinoveÏ skupineï kontrolnõâ). DalsÏ õâ Wassersteinova studie z roku 2003 je zameïrïenaâ opeï t na uâ hel sklonu erupcï nõâ draâ hy druheâ ho dolnõâho premolaâ ru v souvislosti s jeho opozïdeïnyâmvyâvojem. V teâ to praâcimeïrïil na ortopantomogramech u 101 pacientuê uâ hel sklonu erupcï nõâ draâhy vuê cï i mandibulaâ rnõâ linii ve trïech staâ diõâch vyâvoje zaâ rodku druheâ ho dolnõâho premolaâ ru [11]. Krite riempro zarïazenõâ do souboru byl nejmeâneï devõâtimeï sõâcï nõâcï asovyâ odstup dvou ortopantomogramuê. Tohoto kriteria v nasï emsouboru nebylo dosazï eno, nebot' se pro snõâmkovaâ nõâ pacientuê v cï asoveâ m odstupu 9 meïsõâcuê nenasï lo klinickeâ opodstatneïnõâ. Obr.6.Retence/impaktace 45 - kombinace znakuê Fig.6.Unerupted/impacted 45 - features stal inclination of the unerupted/impacted premolar 45. The angle of premolar eruption path showed irregularities especially in teeth 35 and 45. For statistical processing, we selected out of all angular parameters (eruption path of 35 and 45) measured in the control sample and in sample B. The pair t-test of equal mean values revealed that the difference in angle of inclination in sample B and in control sample is statistically insignificant, the level of significance being 5% (p 0.5). The angle of eruption path monitored in individual groups of sample B (retention/impaction of premolar) showed tendency to distal inclination in the maxilla, while mesial and distal inclination was equally represented in the mandible. Discussion Wasserstein discussed the angle of premolar eruption path inclination in his study in He measured angular parameters of the second lower premolars in OPG in 85 children with early loss of the deciduous second molar. He found out that after the early loss of the lower temporary second molar, the second lower premolar showed greater variability of the angle of its eruption path. However, the difference was not statistically significant in comparison with the control group (patients with early loss - the lower second premolar erupted in 79.6, in the control group - the lower second premolar erupted in 83.2 ) [10]. Median of the of the eruption path angle in our control sample (teeth 35 and 45) was 87 (i.e. in comparison with Wasserstein's control group there was a difference of only 3.8 ). Another Wasserstein's study focuses on the angle of the second lower premolar eruption path connected with the late development of the tooth. In OPG of redakce@orthodont-cz.cz

10 ORTODONCIE rocïnõâk17 MeÏrÏenõÂmztra ty mõâsta v opeï rneâ zoâneï v sledovanyâch skupinaâ ch u souboru B (retence/impaktace premolaâ ru) bylo zjisïteï no rozmezõâ pro hornõâ zubnõâ oblouk 1,5-7,6 mm (pruêmeï rnaâ hodnota 4,97 mm) a pro dolnõâ zubnõâ oblouk 0,7-9,2 mm (pruêmeï rnaâ hodnota 4,67 mm). Je patrneâ, zï e pruê meï rneâ hodnoty ztraâ ty mõâsta v opeï rneâ zoâneï v souboru B se pohybujõâ do 5 mm, tzn. meâ neï nezï je meziodistaâ lnõâ rozmeï r premolaâ ru. Da le byla sledovaâ na erupce druheâ ho staâleâ ho molaâru prïed druhyâ mpremolaâ rem. Zde jsme takeâ m eï rïily, jak se tato skutecï nost projevõâ na prostorovyâ ch parametrech v oblasti opeï rneâ zoâ ny. V souboru B byla zjisïteï na pouze jedna hodnota pro hornõâ zubnõâ oblouk (2,5 mm), protozïe v hornõâ cï elisti byl nalezen pouze jeden druhyâ staâlyâ molaâ r prorïezaâ vajõâcõâ prïed druhyâ mpremolaâ rem. Hledane rozmezõâ mohlo byâ t zjisï teï no v dolnõâmzubnõâmoblouku, protozï e zde je vyâskyt erupce druheâ ho staâleâ ho molaâru prïed druhyâ mpremolaâ rempodstatneï cï asteï jsï õâ. PruÊmeÏ rnaâ hodnota ztraâ ty prostoru pro dolnõâ zubnõâ oblouk cï inõâ 4,1 mm (rozmezõâ 0,2 mm - 7,2 mm). Je zrïejmeâ, zï e pruê meï rneâ hodnoty ztraâ ty mõâsta v opeï rneâ zoâ neï zpuê sobeneâ tlakemprorïezaâ vajõâcõâho druheâ ho staâleâ ho molaâ ru a hodnoty ztraâ ty mõâsta v opeï rneâ zoâ neï zpuê sobeneâ prïedcï asnou ztraâ tou docï asnyâ ch zubuê opeï rnou zoâ nu tvorïõâcõâch, jsou velmi podobneâ. PrÏedmeÏ temnasï eho zaâ jmu daâ le byly ageneze premolaâruê. V souboru B mõârneï zde prïevazïoval vyâskyt ageneze v hornõâcï elisti. Take bylo zjisïteï no, zï e v souboru B z devõâti pacientuê s agenezõâ premolaârusev6prïõâpadech objevila retence premolaâ ru protilehleâ ho (skupina B3), tedy u 2/3 souboru. V roce 2002 Shalish v Bostonu publikoval studii, kde se zabyâ val souvislostõâ ageneze premolaâ ru a odchylkou uâ hlu sklonu erupcï nõâ draâ hy premolaâ ru druhostranneâ ho [12]. Zkoumal druheâ dolnõâ premolaâ ry a jejich angulaâ rnõâ parametry v pruê beï hu erupce. Ve sveâ praâ ci Shalish nalezl souvislost ageneze druheâ ho dolnõâho premolaâ ru a distaâ lnõâho sklonu erupcï nõâ draâ hy druhostranneâ ho premolaâ ru. PrÏedpokla daâ, zï e distaâ lnõâ odchylka uâ hlu sklonu druheâ ho dolnõâho premolaâ ru a ageneze premolaâ ru druhostranneâhomaâ genetickou souvislost. V nasï õâ praâ ci se souvislost ageneze premolaâ ru a patologickaâ erupce premolaâ ru projevila takteâ zï. Patologicka erupce se projevila u premolaâ ru druhostranneâ ho nebo sousednõâho. Skupina, kde se tato souvislost klinicky projevila (B3) vsï ak byla maâ lo pocï etnaâ pro potrïeby statistickeâ ho vyhodnocenõâ. Da le jsme se zabyâvaly souvislostmi mezi kombinovanou manifestacõâ potenciaâ lneï patologickyâ ch definovanyâ ch znakuê u retencõâ/impaktacõâ premolaâ ruê. V souboru B (retence/impaktace premolaâ ru) se ve veï tsï ineï prïõâpaduê objevujõâ kombinace dvou a võâce potenciaâ lneï patologickyâ ch znakuê. patients he measured the angle of eruption path inclination to the mandible line during three stages of the development of the germ of second lower premolar [11]. There were two OPG made for each patient, the second one after 9 months. Our sample did not meet the criterion - there were no clinical reasons to make OPG after nine months in our patients. We measured the loss of space in the area of canine and premolars in the individual groups of the sample B (retention/impaction of premolar): in the upper dental arch the interval was mm (mean value = 4.97 mm), in the lower dental arch the interval was mm (mean value = 4.67 mm). The mean loss of space in the area of canine and premolars within the sample B was less than 5 mm, i.e. less than the mesiodistal parameter of the premolar. Further, we monitored the eruption of the second permanent molar that preceded that of the second premolar. We considered spatial parameters in the area of canine and premolars. In the sample B only one value was found for the upper dental arch (2.5 mm), because we found only one permanent second molar erupting prior to second premolar in the maxilla. The range of values was found in the lower dental arch - the occurrence of second permanent molar erupting prior second premolar was much more frequent there. The mean value of lost space for the lower dental arch is 4.1 mm (range from 0.2 mm to 7.2 mm). The mean values of lost space in the area of canine and premolars due to the pressure of the erupting second permanent molar, and values of lost space in the area due to the early loss of temporary dentition creating the area, are very similar. We also paid attention to the premolar agenesis. In the sample B the agenesis in maxilla prevailed. Out of the nine patients with premolar agenesis six showed unerupted opposite premolar (sample B3), i.e. 2/3 of the sample. In Boston 2002, Shalish published his study about the association between premolar agenesis and deviation of the eruption path inclination of the opposite premolar [12]. He focused on second lower premolars and their angular parameters during eruption. He found the link between the missing second lower premolar and the distal inclination of the opposite premolar eruption path. Shalish assumes that the distal deviation of the second lower premolar and agenesis of the opposite premolar are genetically conditioned. The agenesis of premolar and pathological eruption of other premolar occurred in our work, too. Abnormal eruption was found in the opposite or adjacent premolar. However, the group in which this connection was found (B3) was not large enough for the statistical evaluation. redakce@orthodont-cz.cz 31

11 rocïnõâk17 ORTODONCIE Toto zjisïteï nõâ by naâ s mohlo do urcï iteâ mõâry prïiblõâzïit k osveï tlenõâ prïõâcï iny retence/impaktace premolaâ ru. Pro vznik retence/impaktace premolaâruê musõâ byât velmi pravdeï podobneï zastoupeno neï kolik neprïõâznivyâ ch okolnostõâ. Vy skyt jen jednoho potenciaâ lneï patologickeâ ho znaku ve veï tsï ineï prïõâpaduê nevede k retenci/impaktaci premolaâ ru. V souboru B byla nejcï asteïjsï õâ kombinace ztraâ ty mõâsta vopeï rneâ zoâneï a odchylky uâ hlu sklonu erupcï nõâ draâhy (skupina B1). Tuto kombinaci lze pravdeï podobneï povazï ovat za jednu z prïõâcï in retence/impaktace premolaâru. Druha nejcï asteï jsï õâ kombinace, kteraâ vedla k retenci/ impaktaci premolaâ ru byla ztraâ ta mõâsta v opeï rneâ zoâneï, odchylka uâ hlu sklonu erupcï nõâ draâhy zaâ rodku premolaâ ru a erupce druheâ ho staâleâ ho molaâru prïed druhyâm premolaâ rem (soubor B2). I tato kombinace vede k manifestaci retence/impaktace premolaâ ru. DomnõÂva me se, zïe je duê lezïiteâ prïedchaâ zet ztraâteï mõâsta v opeï rneâ zoâ neï pecï livou sanacõâ docï asnyâ ch zubuê tvorïõâcõâch opeï rnou zoâ nu, a tak udrzïovat jejõâ meziodistaâ lnõâ rozmeï r. Tento pozï adavek je trïeba akcentovat zejmeâ na u pacientuê, kde na ortopantomogramu nachaâ zõâme tendence k odchylkaâ mv erupcï nõâ draâ ze zaâ rodku premolaâ ru (sklon, vzaâ jemnaâ kolize) a u pacientuê s atypickyâ mporïadõâm erupce zubuê v lateraâ lnõâmuâ seku chrupu. Z potenciaâ lneï patologickyâ ch znakuê vedoucõâch k retenci/impaktaci premolaâruê dokaâzïeme vcï asnou ortodontickou intervencõâ efektivneï ovlivnit pouze ztraâtumõâ- sta v opeï rneâ zoâneï. DomnõÂva me se, zïe pro dalsï õâstudium tohoto probleâmujetrïeba hledat dalsï õâ souvislosti mezi puê sobenõâmjednotlivyâ ch potenciaâ lneï patologickyâch erupcï nõâch faktoruê premolaâruê a mezi jejich vyâvojem. ZaÂveÏr Absence premolaâruê zubuê v zubnõâch obloucõâch prïedstavuje probleâ m, kteryâ je v rïadeï prïõâpaduê m ozïneâ uâ speïsïneï ortodonticky vyrïesï it. Jednou z cest je co nejdrïõâve odhalit potenciaâ lneï patologickeâ prïõâcï inneâ faktory retence premolaâruê. U pacientuê s retencõâ nebo impaktacõâ premolaâruê dochaâ zelo k sumaci võâce znakuê. V tomto souboru byla ve 44% zastoupena kombinace ztraâ ty mõâsta v opeï rneâ zoâ neï a odchylky uâ hlu sklonu prorïezaâ vajõâcõâho premolaâ ru a v 35% byla zastoupena kombinace ztraâ ty mõâsta v opeï rneâ zoâ neï, odchylky uâ hlu sklonu prorïezaâ vajõâcõâho premolaâ ru a erupce druheâ ho staâleâ ho molaâruprïed druhyâ mpremolaâ rem. MõÂra odchylek v erupcï nõâ draâ ze nebyla pro retenci premolaâ ruê statisticky vyâ znamnaâ. Velmi pravdeï podobneï je tedy retence nebo impaktace premolaâ ruê vyâ sledkemvõâce potenciaâ lneï patologickyâch jevuê a teprve jejich soucï asnyâmvyâskytemv daneâ oblasti dochaâ zõâ k retenci nebo impaktaci premolaâ ru. We also considered the links between the combined manifestations of potentially abnormal features in impacted premolars. In the sample B (unerupted/impacted premolars) there were usually found combinations of two or more potentially pathological features. Therefore, we could try to explain the cause of unerupted/impacted premolars. Several unfavorable conditions must be probably present for the unerupted premolars. In most cases the occurrence of one potentially abnormal feature does not result in the uneruption/impaction of a premolar. Loss of space in the area of canine and premolars together with deviation of the eruption path was the most frequent combination in the sample B (B1). Therefore, the combination seems to be one of the causes of premolar uneruption/impaction. Loss of space in the area, deviation of the inclination of eruption path, and eruption of second permanent molar prior to that of second premolar represented the second most frequent combination (B2). It also resulted in premolar uneruption/impaction. We believe that a thorough care of temporary dentition is the best prevention of loss of space in the area. This should be emphasized especially in the patients whose OPG suggest tendency to deviation of the eruption path of a premolar germ (inclination, mutual collision), and in the patients with atypical order of eruption in the lateral segment. The early orthodontic intervention may effectively influence only the loss of space in the area. We are sure that it is necessary to search for other links between individual factors influencing abnormal eruption of premolars and their development. Conclusion Missing premolars in dental arches pose the problemthat can be successfully solved by the orthodontic treatment. It is essential to discover potentially pathological factors resulting in unerupted premolars as soon as possible. Several factors contributed to the unerupted/impacted premolars. The combination of the loss of space in the area and deviation of erupting premolar represented 44%; the combination of the loss of space in the area, deviation in inclination of premolar, and eruption of the second permanent molar preceding that of the second premolar represented 35%. The deviations of eruption path were not statistically significant for the unerupted premolars. Therefore, we assume that uneruption/impaction of premolars is the result of more potentially pathological phenomena, and only their co-occurrence may lead to the premolar uneruption/impaction redakce@orthodont-cz.cz

12 ORTODONCIE rocïnõâk17 Literatura/References: 1. VoldrÏich, M. a kol.: Stomatologicka protetika. Praha: Sta tnõâ zdravotnickeâ nakladatelstvõâ, KamõÂnek, M.; SÏ tefkovaâ, M.: Ortodoncie I. Olomouc: Univerzita Palacke ho, Proffit, W. R.; Fields, H. W.: Contemporary Orthodontics. 3rd ed., St. Louis: Mosby, Capelozza Filho, L.; Cardoso, Mde. A.; An, T. L.; Bertoz, F. A.: Maxillary canine-first premolar transposition. Angle Orthodont. 2006, 77, cï. 1, s Parekh, S. M.; Fields, H. W.; Beck, M.; Rosenstiel, S.: Attractiveness of variation in the smile arc and buccal corridor space as judged by orthodontists and laymen. Angle Orthodont. 76, cï. 4, s Roden-Johnson, D.; Gallerano, R.; English, J.: The effects of buccal corridor space and arch formon smile esthetics. Amer. J. Orthodont. dentofacial Orthop. 2005, 127, cï. 3, s Maulik, Ch.; Nanda, R.: Dynamic smile analysis in young adults. Amer. J. Orthodont. dentofacial Orthop. 2007, 132, cï. 3, s Moore, T.; Southard, K. A.; Casko, J. S.; Qian, F.; Southard, T. E.: Buccal corridors and smile esthetics. Amer. J. Orthodont. dentofacial Orthop. 2005, 127, cï. 2, s Kot'ovaÂ, M.: Ortodonticky pruê vodce praktickeâ ho zubnõâho leâ karïe. Praha: Grada Publishing, Wasserstein, A.; Shalish, M.: Adequacy of mandibular premolar position despite early loss of its deciduous molar. ADSC J. Dent. Child. 2002, 69, cï. 3, s , Wasserstein, A.; Brezniak, N.; Shalish, M.; Heller, M.; Rakocz, M.: Angular changes and their rates in concurrence to developmental stages of the mandibular second premolar. Angle Orthodont. 2004, 74, cï. 3, s Shalish, M.; Peck, S.; Wasserstein, A.; Peck, L.: Malposition of unerupted mandibular second premolar associated with agenesis of its antimere. Amer. J. Orthodont. dentofacial Orthop. 2002, 121, cï. 1, s MUDr.Hana BenesÏ ovaâ Stomatologicka klinika 3.LF UK Praha SÏ robaâ rova 50, Praha 10