Fluctuating Dental Arch Asymmetry in Different Malocclusion Groups

Svrha: Željelo se usporediti stupanj fluktuirajuće asimetrije (FA) zubnih lukova između pacijenata s anomalijama klase I, II i III. Ispitanici i metode: Uzorak je obuhvaćao slučajno odabrane gipsane modele 131 pacijenta – 39 s klasom I (19 muških i 20 ženskih), 57 s klasom II (23 muška i 34 ženska) i 35 s klasom III (20 muških i 15 ženskih). Dentalni modeli skenirani su i digitalizirani skenerom ATOS II SO. Mjerenja zuba i zubnih lukova obavljena su softverom ATOS viewer verzije 6.A.2. Mjereno je šest širina i pet dužina zubnih lukova. FA je procijenjena u obliku složenog indeksa ukupne težinske asimetrije (TWA). Za komparaciju razlika među skupinama korištena je analiza varijance. Rezultati: Složene TWA mjere fluktuirajuće asimetrije za varijable zubnih lukova bile su najviše u klasi III i najniže u klasi I. Ispitanici su pokazivali viši stupanj asimetrije od ispitanica. Asimetrija zubnih lukova bila je viša u mandibuli negoli u maksili u svim skupinama malokluzija. Zaključci: TWA vrijednosti bile su niske, ali su se značajno razlikovale među skupinama malokluzija. Anomalija klase III pokazivala je više vrijednosti FA-e od onih u klasi I i klasi II. Viša FA-e zubnih lukova u Angleovoj klasi III može se smatrati indikatorom povećane razvojne nestabilnosti u slučaju te malokluzije zbog visokoga genetskog i okolišnog stresa tijekom ranog razvoja.Objective: To compare the degree of dental arch fluctuating asymmetry (FA) among patients with Class I, II, and III malocclusions. Subjects and methods: The sample comprised randomly selected plaster casts of 131 patients: 39 Class I (19 males and 20 females), 57 Class II (23 males and 34 females), and 35 Class III (20 males and 15 females). Dental models were scanned and digitized using ATOS II SO. The measurements of the teeth and dental arches were taken using the ATOS viewer version 6.A.2 software. Six arch widths and five arch depths were measured. The FA was assessed as a composite index of total weighted asymmetry (TWA). The analysis of variance was used to determine whether there were any statistically significant differences between the groups. Results: Composite TWA measures of fluctuating asymmetry for dental arch variables were the highest in Class III, and lowest in Class I malocclusion. Males displayed a higher degree of asymmetry than females. The asymmetry degree was higher in the mandibular dental arches than in the maxillary dental arches in all malocclusion groups. Conclusion: The TWA values were low but they differed significantly between the groups of malocclusion. Class III malocclusion displayed higher FA values than Class I and Class II malocclusion. Higher FA of dental arches in Angle’s Class III can be considered an indicator of increased developmental instability in this malocclusion due to high levels of genetic and environmental stress during the period of early development

Qualitative Analysis of the Enamel Surface After Removal of Remnant Composite

Postupak čišćenja zaostatnoga kompozita pošto je skinuta ortodontska bravica, problem je jer se često ošteti caklinska površina. Svrha je ovoga rada odrediti metodu čišćenja zaostatnoga kompozita koja najmanje oštećuje caklinsku površinu. Istraživanje je provedeno in vitro, na 30 premolara. Bravice su lijepljene i skidane istim postupkom, nakon čega su zubi nasumce podijeljeni u tri skupine. Prva je čišćena Band Driverom, druga tungsten karbidnim svrdlom, a treća klijeπtima za skidanje kompozita. Uzorci su analizirani svjetlosnim stereomikroskopom Olympus. Provedena je raščlamba mikrofotografija i procijenjen Surface Roughness Index (SRI). Najmanje izgrebana površina cakline ostala je nakon tungsten karbidnoga svrdla. Ono se je pokazalo najneškodljivijim sredstvom za čišćenje površine cakline od zaostatnoga sloja kompozita nakon skidanja ortodontskih bravica.Choosing the method of remnant composite removal after debonding is a problem, because most techniques cause deep scratches on the enamel surface. The purpose of this study was to determine the method that causes the least damage to the enamel. The study was carried out on a sample of 30 premolars. After brackets had been bonded and debonded, using the same procedure, the samples were divided at random into three groups. The composite remnants in the first group were removed using the Band Driver, in the second group using a tungsten carbide bur and in the third group using composite removing pliers. The samples were analysed using a light stereomicroscope (Olympus). The photomicrographs were graded and the SRI (Surface Roughness Index) “calculated”. The best enamel surface appearance was determined after using the tungsten carbide bur, which is considered the method which causes the least damage to the enamel surface

Finite Element Method Stress Analysis Caused by Orthodontic Forces

Metoda konačnih elemenata pokazala se uspješnom u raščlambi prijenosa sila i naprezanja u biološkim sustavima. Svrha ovoga istraživanja bila je utvrditi razlike u distribuciji naprezanja i deformacija, ovisno o različitoj razini uporabe jednostavne vodoravne oralno usmjerene sile na labijalnu plohu zuba na matematičkom modelu zuba s pripadajućim potpornim strukturama napravljenom s pomoću metode konačnih elemenata. Kao predložak za izradbu modela poslužio je gornji očnjak izvađen iz parodontoloških razloga. Dobiven je trodimenzionalni model koji se sastoji od 4000 elemenata oblika heksaedra i 2367 čvorova, što čini ukupno 7101 stupanj slobode. Na model je upotrebljena vodoravna oralno usmjerena sila jakosti 1 N na pet različitih razina krune zuba, okomito na njegovu uzdužnu os. Za sva uporabljena opterećenja promatrana je deformacija, intenzitet naprezanja, te su izračunana ekvivalentna naprezanja po energetskoj teoriji čvrstoće (Huber- Mises- Hencky teorija).The method of finite elements has proved to be successful for analysis of the transmission of forces and stress in biological systems. The aim of this investigation was to determine differences in the distribution of stress and deformation, depending on different levels of application of simple horizontal orally directed forces on the labial surface of the tooth using a mathematical model of the tooth, with equivalent supportive structures, constructed means of the finite element method. An upper canine, extracted for periodontal reasons, was used as a pattern for construction of the model. A three-dimensional model was obtained consisting of 4000 elements in the shape of a hexahedron and 2367 nodes, totalling 7101 grades of freedom. Horizontal orally directed 1 N force, was applied to the model on five different levels of the tooth crown, vertically on its longitudinal axis. Deformation and stress intensity were observed for all the applied forces and equivalent stress calculated, according to the energetic theory of strength (Huber-Mises- Hencky theory)

Bioprogressive Therapy and Diagnostics

Bioprogresivna tehnika jest fiksna ortodontska tehnika nastala 1950- -tih godina na temelju edgewise tehnike. Njezin je utemeljitelj Robert Murray Ricketts. Ovaj rad donosi kratak pregled povijesti fiksne ortodoncije, objašnjava nastanak i razvoj Rickettsove tehnike, načela na kojima se temelji i metode kojima se ta tehnika koristi. Naglašen je Rickettsov doprinos ortodontskoj dijagnostici, predviđanju rasta pri planiranju i provedbi ortodontske terapije, a Rickettsova je bioprogresivna “filozofija”, kako ju zove sam autor, dovedena u kontekst i vezu sa suvremenim ortodontskim tehnikama.The bioprogressive technique is a fixed orthodontic technique, developed in the 1950s by Robert Murray Ricketts. This article provides a brief overview of the history of orthodontic practice, explaining the development of “Ricketts technique”, methods and principles that are incorporated in his bioprogressive therapy. It also discusses the importance of diagnostic methods, introduced by the author, that are still recognized as an important part of orthodontic therapy planning. This article explains the influence of bioprogressive philosophy on modern orthodontic techniques

Temporomandibular Disorders and Orthodontic Treatment Need in Orthodontically Untreated Children and Adolescents

The aim of this study was to explore the association between signs and symptoms of temporomandibular disorders (TMD) and orthodontic treatment need in orthodontically untreated children and adolescents. One thousand fi ve hundred and ninety-seven subjects aged 11–19 years, without previous orthodontic history, from sixteen randomly selected public schools in Zagreb, Croatia, were examined. Malocclusion characteristics were assessed by using the criteria proposed by Bjork et al., the Dental Aesthetic Index, and the Aesthetic Component of Index of Orthodontic Treatment Need. Data on TMD signs / symptoms and parafunctional behaviour were obtained by means of questionnaire and clinical examination, respectively. Multiple logistic regression models were used for analysis. Twenty-two percent of children and young adolescents had one or more signs of TMD, ranging from 17% in age of 11 years up to 24% in age of 19. There was poor correlation between presence of TMD and orthodontic treatment need. Multiple logistic regression models showed that Class III, crowding and spacing were related to mandibular defl ection on opening. Ectopic eruption was related to TMJ clicking, and severely tipped teeth with reduced mouth opening. Headaches presented a positive relationship with reverse overjet and severe rotations, and tooth wear with crowding, spacing and lateral openbite. Age, female gender and parafunctional habits were related to several TMD signs. Although logistic regression models were statistically signifi cant (p<0.05) malocclusions, parafunctional behaviours, age and gender accounted for less than 20% of the variability in TMD signs / symptoms. TMD signs and symptoms seemed to be poorly related to malocclusions or treatment needs

Soft Tissue Facial Profile of Normal Dental and Skeletal Subjects in Croatian Population Aged 12 to 15 Years

This study was carried out on 40 lateral cephalograms of Croatian subjects aged 12 to 15 years with dental and skeletal class I. The purpose of this investigation was to determine the means and standard deviations of the soft tissue parameters in the sample of Croatian population exhibiting dental and skeletal class I and to find the correlations between investigated parameters. The investigation included a total of 11 variables of which 4 were angular and 7 linear. Linear and angular measurements were made to the nearest 0.5 mm or 0.5° with dial calipers and a standard protractor with 0.5° increments. Data from this investigation could serve to determine the norms of 11 soft tissue variables for Croatian population with dental and skeletal class I, and to define craniofacial morphology of the soft tissue profile in patients with normal occlusion. Significant correlations were found between thickness of upper and lower lip, and between the distance of upper and lower lip to the Ricketts esthetic line, and Holdaway angle

KORELACIJA MED INDEKSOMA DAI IN ICON PRI VREDNOTENJU POTREBE PO ORTODONTSKEMU ZDRAVLJENJU PRI ŠOLOBVEZNIH OTROCIH NA HRVAŠKEM

Introduction: The aims were: evaluation of the correlation between the Dental Aesthetic Index (DAI) and Index of Complexity, Outcome and Need (ICON); the assessment of orthodontic treatment need for schoolchildren in a population with two indices, separately for schoolchildren with mixed and permanent dentition; the estimation of the population share that could not receive orthodontic treatment because of the presence of caries and/ or gingivitis. Methods: A total of 2652 Zagreb school children (7 - 19 years old, 52.4% of them were females) completed a questionnaire regarding previous orthodontic treatment and the type of appliance used. Their oral cavity was also inspected. The DAI and ICON indices were used for the assessment of malocclusion prevalence. Results: The subjects with mixed dentition had a greater need for orthodontic treatment, when compared to subjects with permanent dentition, when using the DAI index (p<0.001). When using the ICON index, 11.7% of subjects with mixed dentition had very severe malocclusion, as opposed to 5.8% of subjects with permanent dentition. The DAI and ICON scores correlated positively linearly (r=0.521; p<0.001). A higher prevalence of both gingivitis and caries was recorded more often in boys; caries more often in the group with the mixed dentition, and gingivitis in the group with permanent dentition (p<0.05). Conclusion: The DAI and ICON indices have moderate agreement in assessment of malocclusion severity scores. One third of all schoolchildren with various degrees of both ICON and DAI indices have gingivitis, and half of them have caries.Uvod: Cilji študije so: vrednotenje korelacije med indeksom estetskega videza zob (Dental Aesthetic Index, DAI) in indeksom zahtevnosti, izida in potrebe (Index of Complexity, Outcome and Need, ICON); vrednotenje potrebe po ortodontskem zdravljenju v populaciji šoloobveznih otrok z obema indeksoma, posamezna obravnava pri šoloobveznih otrocih z menjalnim in stalnim zobovjem; določanje deleža prebivalstva, ki ni prejela ortodontskega zdravljenja zaradi prisotnosti kariesa in/ali gingivitisa. Metode: 2.552 učencev iz Zagreba (od 7. do 19. leta; od tega 52,4 % učenk) je izpolnilo vprašalnik o njihovem prejšnjem ortodontskem zdravljenju in vrsti zdravljenja, temu je sledil pregled ustne votline. Za vrednotenje razširjenosti malokluzije sta se uporabila indeksa DAI in ICON. Rezultati: Učenci z menjalnim zobovjem imajo večjo potrebo po ortodontskem zdravljenju v primerjavi z učenci s stalnim zobovjem pri uporabi indeksa DAI (p<0,001). Pri uporabi indeksa ICON je imelo 11,7 % učencev z menjalnim zobovjem zelo resno in resno malokluzijo, učenci s stalnim zobovjem pa je 5,8 %. Rezultati indeksov DAI in ICON so medsebojno povezani pozitivno in linearno (r = 0,521; p < 0,001). Večja razširjenost gingivitisa in kariesa je zabeležena pogosteje pri fantih, karies pa bolj pogosto v skupini z menjalnim zobovjem, gingivitis pa v skupini s stalnim zobovjem (p < 0,05). Zaključek: Indeksa DAI in ICON se zmerno ujemata pri rezultatih vrednotenja resnosti malokluzije. Glede na različne stopnje indeksov DAI in ICON ima ena tretjina šoloobveznih otrok gingivitis, polovica pa karies

Stereomicroscope Analysis of Enamel Surface after Orthodontic Bracket Debonding

After orthodontic brackets debonding, the remaining resin has to be removed. The purpose of this study was to determine the most efficient method as well as to introduce a new method of composite removal. The study was carried out on a sample of 30 premolars, extracted for orthodontic purposes. Brackets had been bonded using the Ortho One Bisco composite resin. After the removal of brackets, samples were randomly divided into three groups of ten. Composite remnants in the first group were removed using the Band Driver (KaVo). For the second group, the tungsten carbide bur (Komet) was applied. In the third group, composite remnants were removed manually, using adhesive removing pliers (ORMCO). The samples were analysed using a light-stereomicroscope (Olympus). Photomicrographs were examined and the ARI (Adhesive Remnant Index) was calculated. Post Hoc tests (Scheffe, Tukey) indicated a statistically significant difference between groups 1 and 2 as well as between groups 1 and 3. The tungsten carbide bur was found to be the most efficient instrument for composite remnant removal

Fluctuating Dental Arch Asymmetry in Different Malocclusion Groups

Objective: To compare the degree of dental arch fluctuating asymmetry (FA) among patients with Class I, II, and III malocclusions. Subjects and methods: The sample comprised randomly selected plaster casts of 131 patients: 39 Class I (19 males and 20 females), 57 Class II (23 males and 34 females), and 35 Class III (20 males and 15 females). Dental models were scanned and digitized using ATOS II SO. The measurements of the teeth and dental arches were taken using the ATOS viewer version 6.A.2 software. Six arch widths and five arch depths were measured. The FA was assessed as a composite index of total weighted asymmetry (TWA). The analysis of variance was used to determine whether there were any statistically significant differences between the groups. Results: Composite TWA measures of fluctuating asymmetry for dental arch variables were the highest in Class III, and lowest in Class I malocclusion. Males displayed a higher degree of asymmetry than females. The asymmetry degree was higher in the mandibular dental arches than in the maxillary dental arches in all malocclusion groups. Conclusion: The TWA values were low but they differed significantly between the groups of malocclusion. Class III malocclusion displayed higher FA values than Class I and Class II malocclusion. Higher FA of dental arches in Angle’s Class III can be considered an indicator of increased developmental instability in this malocclusion due to high levels of genetic and environmental stress during the period of early development

Comparison of Shear Bond Strength of Orthodontic Brackets Using Direct and Indirect Bonding Methods in Vitro and in Vivo

AIM: Aim of article was to compare the shear bond strength of indirectly and directly bonded orthodontic brackets. MATERIALS AND METHODS: The experimental in vitro study included 60 maxillary and mandibular premolars. Teeth were mounted on cold-cure acrylic blocks for each tooth separately and divided into two groups: directly bonded brackets (30 teeth) and indirectly bonded brackets (30 teeth). Brackets (Discovery, Roth 0.022", Dentaurum, Ispringen, Germany) were bonded using Transbond XT (3M Unitek, Monrovia, CA, USA) in direct method, while in indirect technique, a combination of Transbond XT and Sondhi Rapid Set (3M Unitek, Monrovia, CA, USA) was used. The shear bond strength and adhesive remnant index (ARI) were evaluated. The in vivo study included 30 subjects - 15 with indirectly bonded brackets and 15 with directly bonded brackets. Survival rate was assessed during the period of 6 months. RESULTS: No statistically significant difference in the shear bond strength was found in direct (7.48±1.61 MPa) and indirect labial bonding methods (7.8.2±1.61 MPa). Both methods produced very similar amount of adhesive remnant on tooth surface (median = 1 ; interquartile range 1-2). There were no significant differences in bracket survival rate between methods. CONCLUSION: Regarding the shear bond strength, adhesive remnant on tooth surface, and survival rate, both indirect and direct methods of orthodontic bracket bonding seem to be equally valuable methods in clinical practice