La caducidad como acto administrativo extracontractual:

and esthetic results after surgery

*MUDr. Eva MichalcovaÂ, *MUDr. Hana TycovaÂ, *MUDr. Josef KucÏera, **RNDr. JaromõÂr BeÏlaÂcÏek, CSc. *Ortodonticke oddeÏlenõ Stomatologicke kliniky 1. LF UK Praha

*Department of Orthodontics, Clinic of Stomatology, 1st Medical Faculty of Charles University in Prague **OddeÏlenõÂ Biostat prÏi UÂstavu biofyziky a informatiky, 1. LF UK Praha

**Biostat, Institute of Biophysics and Information Technologies, 1st Medical Faculty of Charles University Pra- gue

Souhrn

Studie se zabyÂvala vlivem prÏedoperacÏnõÂho zachovaÂnõÂ Speeovy krÏivky v dolnõÂm zubnõÂm oblouku na estetiku dol- nõÂ trÏetiny oblicÏeje u pacientuÊ s II. skeletaÂlnõÂ trÏõÂdou a ortognaÂtnõÂm posunem dolnõÂ cÏelisti smeÏrem doprÏedu. U pa- cientuÊ se zachovanou Speeovou krÏivkou bylo prÏedpoklaÂdaÂno, zÏe po operaci dojde ke zveÏtsÏenõÂ vertikaÂlnõÂch para- metruÊ a mensÏõÂ prominenci bradoveÂho vyÂbeÏzÏku.

Soubor obsahoval 36 dospeÏlyÂch pacientuÊ s II. skeletaÂlnõ trÏõÂdou, rozdeÏlenyÂch do dvou skupin podle hloubky Speeovy krÏivky prÏed ortognaÂtnõ operacõÂ. Skupinu A (n = 18, 9 zÏen, 9 muzÏuÊ) tvorÏili pacienti se zachovanou Speeo- vou krÏivkou (HS ³ 3 mm). Skupinu B (n = 18, 7 zÏen, 11 muzÏuÊ) tvorÏili pacienti s vyrovnanou Speeovou krÏivkou (HS £ 2 mm). U vsÏech pacientuÊ byly zhodnoceny trÏi kefalometricke snõÂmky, prÏed zahaÂjenõÂm ortodonticke leÂcÏby (T0), prÏed ortognaÂtnõ operacõ (T1) a po sejmutõ fixnõÂho aparaÂtu (T2).

PorovnaÂnõÂm vyÂsledkuÊ mezi skupinami pacientuÊ byly potvrzeny statisticky signifikantnõ rozdõÂly pouze u hloubky skusu. U pacientuÊ s vyrovnanou Speeovou krÏivkou prÏed operacõ dosÏlo k statisticky signifikantnõÂmu zmensÏenõ hloubky skusu beÏhem ortodonticke prÏedoperacÏnõ prÏõÂpravy (T1-T0), zatõÂmco u pacientuÊ se zachovanou Speeovou krÏivkou prÏed operacõ dosÏlo k statisicky signifikantnõ redukci hloubky skusu azÏv obdobõ beÏhem operace a ortodon- tickeÂho doleÂcÏenõ po operaci (T2-T1). U ostatnõÂch sledovanyÂch parametruÊ nebyly prokaÂzaÂny statisticky signifi- kantnõ rozdõÂly mezi skupinou pacientuÊ se zachovanou a vyrovnanou Speeovou krÏivkou(Ortodoncie 2012, 21, cÏ. 2, s. 94-101).

Abstract

The impact of preserved Spee curve in the lower dental arch prior to surgery on the esthetics of the lower third of face in patients with Class II and orthognathic advancement of the mandible is studied. It was hypothesized that in patients with preserved Spee curve the vertical parameters would increase and mental protuberance would be less prominent after surgical management.

The sample had 36 adult patients with Class II, subdivided into two groups according to the depth of the Spee curve prior to orthognathic surgery. Group A (n = 18, 9 females, 9 males) included patients with preserved Spee curve (DB ³ 3 mm). Group B (n = 18, 7 females, 11 males) included patients with leveled Spee curve (DB £ 2 mm).

In all patients three cephalograms were taken: prior to orthodontic treatment (T0), prior to orthognathic surgery (T1), after the removal of fixed orthodontic appliance (T2).

Comparison of results between groups of patients proved statistically significant differences only in the over- bite. In patients with leveled Spee curve before the surgery statistically significant reduction of depth of bite du- ring the treatment prior to surgery (T1-T0) was observed, whilst in patients with preserved Spee curve before sur- gery the depth of bite significantly reduced only in the period following the intervention and during the orthodon- tic after-treatment (T2-T1). In other parameters monitored no statistically significant differences were recorded

(Ortodoncie 2012, 21, No. 2, p. 94-101).

KlõÂcÏova slova: Speeova krÏivka, ortognaÂtnõ operace, skeletaÂlnõ II.trÏõÂda Key words: curve of Spee, orthognathic surgery, skeletal Class II

Introduction

Combined orthodontic-orthognathic therapy is in- dicated in patients with serious Skeletal Class II, the condition in which orthodontic compensation therapy might lead to esthetically insufficient outcome. In case a patient decides for orthognathic surgery, an ortho- dontist has to prepare dentalarches in such way that the intervention result is not only functional but meets also esthetic standards.

In patients with skeletal Class II, vertical deficit, and expressed mentalprotuberance some authors recom- mend to preserve a distinct curve of Spee in the lower dentalarch [1, 2, 3, 4, 5, 6]. In case lower incisors are not intruded prior to surgery, they move more down- wards along lingual surface of maxillary incisors during advancement of the mandible [7]. Thus the mandible rotates clockwise, the lower third of face is longer and mentalprotuberance is reduced [4, 5, 6, 7]. The curve of Spee is leveled after surgery by lateral se- gments extrusion through vertical intermaxillary ela- stics. Moreover, due to the Spee curve levelling it is not necessary to fight the extensive masticatory force of patients, which is otherwise typicalin patients with deep bite, and, therefore, the treatment is shorter [7].

The aim of our study was to determine the role of the curve of Spee arrangement in the lower dental arch on the esthetics of the lower third of face in patients with Skeletal Class II after the mandible advancement wi- thin the cooperation between an orthodontist and an orthognathic surgeon.

Material

The sample had 44 adults with Skeletal Class II. 8 patients were eliminated from the sample due to in- complete records, bad quality of cephalograms, or be- cause they did not meet the conditions of group A or B. Thus the finalsample had 36 patients - 16 women and 20 men. All patients were Caucasians with finished growth, and they underwent monomaxillary surgery in- volving the mandible advancement.

For each patient there were made three cephalo- grams - before orthodontic treatment (T0), before UÂvod

Kombinovana ortodonticko-chirurgicka terapie je indikovaÂna u pacientuÊ se zaÂvazÏnou skeletaÂlnõ II. trÏõÂdou, kde by kompenzacÏnõ ortodonticka l eÂcÏba vedla k este- ticky nevyhovujõÂcõÂmu vyÂsledku. Pokud se pacient roz- hodne podstoupit ortognaÂtnõ operaci, je uÂkolem orto- dontisty prÏipravit zubnõ oblouky tak, aby vyÂsledek po operaci bylnejen funkcÏnõÂ, ale take co nejvõÂce estetickyÂ. U pacientuÊ s II. skeletaÂlnõ trÏõÂdou, vertikaÂlnõÂm deficitem a vyÂraznyÂm bradovyÂm vyÂbeÏzÏkem je neÏkteryÂmi autory doporucÏovaÂno prÏed operacõ zachovaÂnõ vyÂrazne Speeovy krÏivky v dolnõÂm zubnõÂm oblouku [1, 2, 3, 4, 5, 6]. Pokud nejsou dolnõ rÏezaÂky prÏedoperacÏneÏ intrudo- vaÂny, dostaÂvajõ se beÏhem chirurgickeÂho posunu dolnõ cÏelisti smeÏrem doprÏedu po lingvaÂlnõ plosÏe hornõÂch rÏe- zaÂkuÊ võÂce doluÊ [7]. TõÂm dochaÂzõ k rotaci dolnõ cÏelisti po smeÏru hodinovyÂch rucÏicÏek, zveÏtsÏenõ dolnõ trÏetiny obli- cÏeje a zmensÏenõ prominence bradoveÂho vyÂbeÏzÏku [4, 5, 6, 7]. Speeova krÏivka je vyrovnaÂna po chirurgickeÂm vyÂ- konu extruzõ lateraÂl nõÂch uÂsekuÊ pomocõ vertikaÂlnõÂch inter- maxilaÂrnõÂch elastickyÂch tahuÊ. NavõÂc, pooperacÏnõÂm vy- rovnaÂnõÂm Speeovy krÏivky nenõ nutne prÏekonaÂvat velke zÏvyÂkacõ sõÂly typicke pro pacienty s hlubokyÂm skusem a je mozÏne zkraÂtit celkovou dobu leÂcÏby [7].

CõÂlem teÂto studie bylo urcÏit vliv prÏõÂpravy Speeovy krÏivky v dolnõÂm zubnõÂm oblouku na estetiku dolnõ trÏe- tiny oblicÏeje u pacientuÊ s II. skeletaÂlnõ trÏõÂdou po posunu dolnõ cÏelisti smeÏrem doprÏedu v raÂmci ortodonticko- chirurgicke spolupraÂce.

MateriaÂl

VysÏetrÏovany soubor tvorÏilo 44 dospeÏl yÂch pacientuÊ s II. skeletaÂlnõ trÏõÂdou. Z tohoto souboru muselo byÂt vy- loucÏeno 8 pacientuÊ pro neuÂplnou dokumentaci, nedo- statecÏnou cÏitelnost kefalometrickyÂch snõÂmkuÊ nebo ne- splneÏnõ podmõÂnek pro zarÏazenõ do skupiny A nebo B. Z teÏchto duÊvoduÊ konecÏny soubor obsahoval36 pa- cientuÊ - 16 zÏen a 20 muzÏuÊ. VsÏichni pacienti byli bõÂle rasy, s ukoncÏenyÂm ruÊstem a podstoupili monomaxi- laÂrnõ operaci s posunem dolnõ cÏelisti smeÏrem doprÏedu.

U vsÏech pacientuÊ byly zhodnoceny trÏi kefalome- tricke snõÂmky a to prÏed zahaÂjenõÂm ortodonticke l eÂcÏby

orthognathic surgery (T1), and after removalof fixed appliance (T2).

The sample was divided into two groups according to the depth of Spee curve at T1. Group A (n=18, 9 women, 9 men) involved patients with preserved curve of Spee, the depth of which at T1 ³ 3 mm. The mean depth of Spee curve at T1 was 3.23 mm, standard deviation (SD) 0.24. Group B (n=18, 7 women, 11 men) involved patients with levelled Spee curve, the depth of which was at T1 £ 2 mm. The mean depth of Spee curve at T1 £ 1.57, SD 0.39. Patients with the depth of Spee curve of 2.1 - 2.9 mm were excluded from the sample.

Cephalograms were traced manually by one and the same person using negatoscope and acetate film, with the accuracy of 0.5 mm or 0.5°. Cephalograms were obtained from different sources; therefore, in each cephalogram there was determined coefficient of enlargement and all linear parameters were multiplied by the coefficient so that the resulting values corre- sponded to actualdimensions.

Method

The depth of Spee curve was evaluated in cephalo- grams taken at T1. In each image the curve of Spee (T0), prÏed ortognaÂtnõÂ operacõÂ (T1) a po sejmutõÂ fixnõÂho

aparaÂtu (T2).

Soubor pacientuÊ bylrozdeÏlen do dvou zaÂkladnõÂch skupin podle hloubky Speeovy krÏivky v cÏase T1. Sku- pinu A (n = 18, 9 zÏen, 9 muzÏuÊ) tvorÏili pacienti se zacho- vanou Speeovou krÏivkou a hloubkou Speeovy krÏivky prÏed operacõ v cÏase T1 ³ 3mm. PruÊmeÏrna hloubka Speeovy krÏivky u skupiny A v cÏase T1 byla 3,23 mm a smeÏrodatna odchylka (SD) 0,24. Skupinu B (n = 18, 7 zÏen, 11 muzÏuÊ) tvorÏili pacienti s vyrovnanou Speeovou krÏivkou a hloubkou Speeovy krÏivky prÏed operacõÂv cÏase T1 £ 2mm. PruÊmeÏrna hloubka Speeovy krÏivky u sku- piny B v cÏase T1 byla 1,57 mm a SD 0,39. Pacienti s hloubkou Speeovy krÏivky 2,1 - 2,9 mm byli ze sou- boru pacientuÊ vyrÏazeni.

Kefalometricke snõÂmky byly prÏekreslovaÂny rucÏneÏ jednou osobou na negatoskopu na acetaÂtovy papõÂr s prÏesnostõ 0,5 mm nebo 0,5°. SnõÂmky byly zõÂskaÂvaÂny z ruÊznyÂch zdrojuÊ, proto bylo nutne na kazÏdeÂm snõÂmku stanovit dle meÏrÏõÂtka koeficient zveÏtsÏenõ a vsÏechny li- neaÂrnõ hodnoty jõÂm vynaÂsobit, aby vyÂsledne hodnoty odpovõÂdaly skutecÏnyÂm velikostem.

Metodika

Hloubka Speeovy krÏivky byla hodnocena na kefalo- metrickyÂch snõÂmcõÂch zhotovenyÂch v cÏase T1. Na kazÏ- deÂm snõÂmku byla vyznacÏena Speeova krÏivka jako linie sahajõÂcõ od incizaÂlnõÂch hran dolnõÂch rÏezaÂkuÊ, pokracÏujõÂcõ prÏes hrot sÏpicÏaÂku a hrbolky premolaÂruÊ na hrbolky nej- võÂce distaÂl neÏ ulozÏenyÂch plneÏ prorÏezanyÂch zubuÊ. Jejõ hloubka byla hodnocena v mõÂsteÏ nejveÏtsÏõ konvexity jako kolmice k prÏõÂmce sahajõÂcõ od incizaÂlnõÂch hran dol- nõÂch rÏezaÂkuÊ k distaÂlnõÂmu hrbolku nejvõÂce vzadu prorÏe- zaneÂho zubu. Hodnocenõ hloubky Speeovy krÏivky je patrne z obraÂzku cÏ. 1.

Na kefalometrickyÂch snõÂmcõÂch v cÏase T0, T1 a T2 byly hodnoceny 4 parametry uÂhloveÂ, 5 parametruÊ l i- neaÂrnõÂch a vypocÏteny 2 pomeÏrne indexy (Tab. 1, Obr. 3). NeÏktere byly stanoveny za pomoci horizon- taÂlnõ referencÏnõ linie (HRL), prochaÂzejõÂcõ bodem Sela

Obr. 1. HodnocenõÂ hloubky Speeovy krÏivky Fig. 1. Evaluation of the depth of Spee curve

Obr. 2a - pacient se zachovanou Speeovou krÏivkou prÏed operacõÂ v cÏase T1, b - pacient s vyrovnanou Speeovou krÏivkou prÏed operacõÂ Fig. 2a - patient with retained Spee curve at T1, b - patient with le- velled Spee curve at T1.

was represented as the line running from incisal edge of lower incisors, continuing over canine tip and pre- molars cusps onto the cusps of fully erupted most di- stalteeth. The depth was evaluated in the point of the greatest convexity as a perpendicular to the straight line running from incisal edge of lower incisors to the distalcusp of the most distalerupted tooth. The eva- luation is represented in Figure 1.

In cephalograms taken at T0, T1, and T2, there were evaluated 4 angular parameters, 5 linear parameters, and 2 proportional indexes were calculated (Fig. 3). Some of them were determined with the help of hori- zontal reference line (HRL), running through Sella point and containing with SN line 7°, and verticalreference line (VRL), perpendicular to HRL and running through Subnasale.

Some parameters:

LAFH - lower anterior facial height, distance of Spina nasalis anterior and Menton parallel with VRL,

APFH index - proportion of posterior and anterior fa- cialheight, SGo/NMe,

AFH index - proportion of anterior facialheight and overal anterior facial height parallel to VRL, Spa-Me/N- Me.

Measurements were fed into Excel(Microsoft Office, 2007). For all values there was assessed arith- metic mean, median, minimum and maximum value, and standard deviation.

The data were statistically processed with Statistica 9 (Statsoft) and SPSS 17. Normaldistribution of the data in both groups was tested with Kolmogorov- Smirnov test, and tests based on selective skewness and selective kurtosis. To establish statistical signifi- cance of differences between measurements done at a svõÂrajõÂcõÂ s liniõÂ SN 7° a vertikaÂlnõÂ referencÏnõÂ linie (VRL),

kolme k HRL a prochaÂzejõÂcõ Subnasale. NeÏktere parametry:

LAFH - dolnõ prÏednõ oblicÏejova vyÂsÏka, vzdaÂlenost Spina nasalis anterior a Menton paralelnõ s VRL,

APFH index - pomeÏr zadnõ oblicÏejove vyÂsÏky a prÏednõ oblicÏejove vyÂsÏky, SGo/NMe,

AFH index - pomeÏr dolnõ prÏednõ oblicÏejove vyÂsÏky a celkove prÏednõ oblicÏejove vyÂsÏky paralelnõ k VRL.

VyÂsledky meÏrÏenõ byly vlozÏeny do tabulkoveÂho pro- gramu Excel(Microsoft Office, 2007). U vsÏech nameÏrÏe- nyÂch hodnot bylstanoven aritmeticky pruÊmeÏr, mediaÂn, minimaÂlnõ a maximaÂlnõ hodnota a smeÏrodatna odchylka. Data byla statisticky zpracovaÂna v programu Stati- stica 9 (Statsoft) a SPSS 17. NormaÂlnõ distribuce dat byla u obou skupin testovaÂna pomocõ Kolmogorov-Smirno- vova testu a pomocõ testu zalozÏeneÂho na vyÂbeÏrove sÏik- mosti (skewness) a vyÂbeÏrove sÏpicÏatosti (kurtosis). Pro zji-

Úhlové parametry Angular parameters (°) Lineární parametry Linear parameters (mm) Poměrné indexy Proportional indexes

SNB Wits APFH index

ANB OB (HS) AFH index

SNML OJ (IS)

NLML Pog

LAFH

Tab. 1. MeÏrÏene rozmeÏry Tab. 1. Measurements

Popis parametruÊ je v legendeÏ k obr. 3, description of measurements in legend to Fig. 3

3 Obr. 3. RozmeÏry na kefalometrickeÂm snõÂmku Fig.3: Measurement on cephalogram

HRL - horizontaÂlnõÂreferencÏnõÂlinie, horizontal reference line, VRL - ve- rtikaÂlnõÂ referencÏnõÂ linie, vertical reference line, OB (HS) - hloubka skusu, vzdaÂlenost Incisale superius a Incisale inferius paralelnõÂ s VRL, overbite, distance of Incisale superius and Incisale inferius parallel with VRL, OJ (IS) - incizaÂlnõÂ schuÊdek, vzdaÂlenost Incisale su- perius k bukaÂlnõÂmu povrchu dolnõÂho rÏezaÂku, overjet, distance bet- ween Incisale superius and buccal surface of lower incisor, Pog - po- zice brady, vzdaÂlenost bodu Pogonion a VRL paralelnõÂ s HRL, chin position, distance of Pogonion and VRL parallel with HRL.

T0, T1 and T2, paired t-test was used in groups, and two-sample t-test between the groups. All tests were performed on the level of statistical significance 0.05.

Results

Within groups A and B the mean values of individual parameters measured at T0, T1, T2 were compared with paired t-test at T1-T0, T2-T0, and T2-T1.

In Group A (preserved Spee curve) the statistically significant difference was found in the following para- meters: at T1-T0 for parameter OB; at T2-T0 and T2-T1 for parameters SNB, ANB, Wits, OB, IS, NSML, NLML, Pog, LAFH and AFH. The results are summarized in Ta- ble 4.

In Group B (levelled Spee curve) the statistically sig- nificant difference was found in the following parame- ters: at T1-T0 for OB, LAFH, APFH index, AFH index; at T2-T0 for SNB, ANB, Wits, OB, OJ, NSML, NLML, Pog, LAFH, AFH index; at T1-T2 for SNB, ANB, Wits, OB, OJ, NSML, NLML, Pog, LAFH (Table 5).

To compare mean differences between groups A and B in different parameters measured between T1-T0, T2-T0, and T2-T1, two-sample t-test was used. Statistically significant difference was found in OB at sÏteÏnõÂstatisticke vyÂznamnosti rozdõÂluÊ mezi meÏrÏenõÂm v cÏase

T0, T1 a T2 ve skupinaÂch bylpouzÏit paÂrovy t-test a mezi skupinami dvouvyÂbeÏrovy t-test. VsÏechny testy byly pro- vedeny na hladineÏ statisticke vyÂznamnosti 0,05.

VyÂsledky

V raÂmci skupin A a B byly pruÊmeÏrne hodnoty jedno- tlivyÂch meÏrÏenyÂch parametruÊ v cÏasech T0, T1, T2 po- rovnaÂvaÂny paÂrovyÂm t-testem mezi cÏasy meÏrÏenõ T1- T0, T2-T0 a T2-T1.

U skupiny A (zachovana Speeova krÏivka) bylprokaÂ- zaÂn statisticky signifikantnõ rozdõÂlv naÂsledujõÂcõÂch para- metrech: v cÏase T1-T0 u parametru HS, v cÏase T2-T0 a T2-T1 u meÏrÏenyÂch parametruÊ SNB, ANB, Wits, HS, IS, NSML, NLML, Pog, LAFH a AFH indexu. VyÂsledky jsou patrne z tabulky cÏ. 4.

U skupiny B (vyrovnana Speeova krÏivka) bylprokaÂ- zaÂn statisticky signifikantnõ rozdõÂlv naÂsledujõÂch para- metrech: v cÏase T1-T0 u parametruÊ HS, LAFH, APFH indexu, AFH indexu, v cÏase T2-T0 u SNB, ANB, Wits, HS, IS, NSML, NLML, Pog, LAFH, AFH indexu a v cÏase T1-T2 u SNB, ANB, Wits, HS, IS, NSML, NLML, Pog, LAFH (Tab. 5).

Pro porovnaÂnõÂ pruÊmeÏrnyÂch rozdõÂluÊ mezi skupinami A a B v jednotlivyÂch meÏrÏenyÂch parametrech mezi cÏasy

Skupina A, Group A

T0 T1 T2

Mean SD Mean SD Mean SD

SNB 75.28 3.23 75.11 3.20 78.50 3.15 ANB 5.83 2.20 5.50 2.08 1.67 1.99 Wits 7.83 3.44 7.62 3.90 -0.44 2.65 OB(HS) 7.63 1.97 6.54 1.57 2.91 0.72 OJ(IS) 7.93 4.29 8.78 3.09 2.42 0.67 SNML 26.36 7.01 27.11 7.77 29.75 7.26 NLML 18.58 6.21 18.89 6.66 21.61 6.60 Pog 25.36 4.45 25.22 4.69 19.10 4.62 LAFH 59.46 5.23 60.37 5.39 62.94 6.11 APFH 0.61 0.067 0.63 0.128 0.68 0.215 AFH 0.46 0.039 0.47 0.094 0.55 0.186

Tabulka cÏ. 2: Hodnoty u skupiny A (zachovana Speeova krÏivka v T1). Table 2: Values for group A (preserved Spee curve at T1)

Skupina B, Group B

T0 T1 T2

Mean SD Mean SD Mean SD

SNB 77.11 3.29 77.14 3.19 80.25 2.38 ANB 6.28 1.90 6.22 2.03 2.64 1.80 Wits 8.02 2.53 7.37 2.30 1.50 2.68 OB (HS) 7.47 2.51 5.08 1.72 2.89 0.80 OJ (IS) 6.76 4.19 7.86 2.59 2.56 0.79 SNML 25.06 5.88 25.31 5.57 26.94 4.63 NLML 19.17 6.34 19.22 5.82 21.03 6.00 Pog 25.50 4.49 26.01 4.47 20.60 3.80 LAFH 59.55 6.81 62.93 7.16 65.49 7.81 APFH 0.63 0.076 0.72 0.193 0.75 0.255 AFH 0.46 0.052 0.53 0.144 0.61 0.251

Tabulka cÏ. 3: Hodnoty u skupiny B (vyrovnana Speeova krÏivka v T1) Table 3: Values for group B (levelled Spee curve at T1)

Skupina A, Group A

∆ T1 -T0 ∆ T2 -T0 ∆ T2 -T1

Mean SD Sig. Mean SD Sig. Mean SD Sig.

SNB _{-0.17 0.86 3.22 1.40 *** 3.39 1.50 ***} ANB _{-0.33 1.06 -4.16 2.04 *** -3.83 2.03 ***} Wits _{-0.21 2.14 -8.27 3.44 *** -8.06 3.78 ***} OB (HS) _{-1.08 1.27 ** -4.72 1.76 *** -3.63 1.54 ***} OJ (IS) _{0.86 5.13 -5.51 4.22 *** -6.36 2.80 ***} NSML _{0.75 1.95 3.39 3.48 *** 2.64 2.33 ***} NLML _{0.31 0.94 3.03 2.40 *** 2.72 2.05 ***} Pog _{-0.13 2.08 -6.26 2.25 *** -6.12 3.05 ***} LAFH _{0.91 2.12 3.49 3.09 *** 2.58 1.84 ***} APFH _{0.02 0.10 0.08 0.20 0.06 0.14} AFH _{0.01 0.08 0.09 0.17 * 0.08 0.12 *}

Tabulka cÏ. 4: ZmeÏny u skupiny A (zachovana Speeova krÏivka v T1) Table 4: Changes in Group A (preserved Spee curve at T1)

*, **, *** statisticky vyÂznamny rozdõÂl na hladineÏ spolehlivosti 95 %, 99 %, 99,9 % *, **, *** statistically significant difference on the level of reliability 95 %, 99 %, 99.9 %

Skupina B, Group B

Parameters

measured _{∆ T1 -T0 ∆ T2 -T0 ∆ T2 -T1}

Mean SD Sig. Mean SD Sig. Mean SD Sig. SNB _{0.03 1.16 3.14 1.43 *** 3.11 1.55 ***} ANB _{-0.06 1.24 -3.64 1.89 *** -3.58 1.87 ***} Wits _{-0.66 1.97 -6.52 3.85 *** -5.87 3.14 ***} OB (HS) _{-2.39 2.06 *** -4.58 2.43 *** -2.19 1.62 ***} OJ (IS) _{1.10 3.44 -4.19 4.19 *** -5.29 2.46 ***} NSML _{0.25 1.71 1.89 2.33 ** 1.64 2.04 **} NLML _{0.06 1.32 1.86 2.36 ** 1.81 2.20 **} Pog _{0.51 1.61 -4.90 2.59 *** -5.40 2.97 ***} LAFH _{3.38 5.83 * 5.94 6.62 ** 2.56 4.27 *} APFH _{0.09 0.17 * 0.12 0.24 0.03 0.12} AFH _{0.07 0.14 * 0.16 0.23 * 0.08 0.18}

Tabulka cÏ. 5: ZmeÏny u skupiny B (vyrovnana Speeova krÏivka v T1) Table 5: Changes in Group B (levelled Spee curve at T1)

*, **, *** statisticky vyÂznamny rozdõÂlna hladineÏ spolehlivosti 95 %, 99 %, 99,9 % *, **, *** statistically significant difference on the level of reliability 95 %, 99 %, 99.9 %

Group Mean SD Sig.

A -1.08 1.27

OB

B -2.39 2.06

*

Tabulka cÏ. 6: RozdõÂly v cÏase T1-T0 mezi skupinou A a B u hloubky skusu Table 6: Differences at T1-T0 between A and B for overbite

* statisticky vyÂznamny rozdõÂlna hladineÏ spolehlivosti 95 % * statistically significant difference on the level of reliability 95 %

Group Mean SD Sig.

A -3.63 1.54

OB

B -2.19 1.62

**

Tabulka 7. RozdõÂly v cÏase T2-T1 mezi skupinou A a B u hloubky skusu Table 7 Differences at T2-T1 between A and B for overbite

** statisticky vyÂznamny rozdõÂlna hladineÏ spolehlivosti 99 % ** statistically significant difference on the level of reliability 99 %

T1-T0, and T2-T1. There were no significant differen- ces in the rest of parameters.

Discussion

This study aimed to evaluate the impact of retained Spee curve before the orthognathic advancement of the mandible on vertical facial parameters and the po- sition of Pogonion point after surgery.

The evaluation of results obtained in groups A and B proved in patients with levelled Spee curve (group B) during orthodontic pretreatment (T1-T0) statistically significant reduction of overbite, and statistically signi- ficant increase in parameters LAFH, APFH index and AFH index. The results therefore suggest that levelling of Spee curve, especially through extrusion of lateral segments, affects verticalparameters and results in enlargement of the lower third of face.

In the period of surgical intervention till the comple- tion of therapy and removalof fixed appliance (T2-T1) in both groups there were observed the following changes: statistically significant increase in SNB, re- duction of ANB, Wits, overbite, and overjet. In vertical parameters, in both groups, there was observed stati- stically significant increase of NSML, NLML, LAFH, and in patients with retained Spee curve (group A) also statistically significant increase of AFH index. In both groups there was statistically significant advancement of bone Pogonion.

Statistically significant differences that occurred in the course of the whole treatment, i.e. from the appli- cation of fixed appliance till its removal at the end of therapy (T2-T1) were the same in both groups. Statisti- cally significant increase of values was observed in pa- rameters SNB, NSML, NLML, LAFH, AFH index, re- duction of ANB, Wits, OB, IS, and advancement of bone Pogonion forward.

In patients with preserved Spee curve prior to sur- gery (group A) statistically significant changes are ob- served only after surgery. In patients with levelled Spee curve (group B) statistically significant changes are ob- served as early as during orthodontic pretreatment prior to surgery; statistically significant enlargement of lower anterior facial height, and APFH, AFH indexes. Evaluation of parameters between the groups sho- wed statistically significant differences only in overbite (OB). During orthodontic pretreatment prior to surgery (T1-T0), in patients with levelled Spee curve (group B) there was more substantialreduction of overbite, and

In document La naturaleza jurídica de la cláusula de caducidad en los contratos de Hidrocarburos en el Ecuador (página 73-76)