Analysis of orthodontic and orthodontic-surgical treatment effect on upper airways and facial soft-tissues using CBCT

Abstract

Three-dimensional (3D) nature of the human body and head had been analysed ever since the antient times. At the beginning of the 20th century plaster was the basic diagnostic material used for representing dentofacial morphology, so most orthodontists used plaster study models to analyse the dentition and the alveolar bone. Some more ambitious clinitians, amongst them Calvin Case, even suggested the use of facial moulages in order to capture the pre- and posttreatment facial morphology. Introduction of cephalometrics to orthodontics in the mid 1920-ies enabled describing craniofacial morphology and growth, predicting growth, planning treatment and evaluating treatment outcomes. However, even back in the 1960-ies orthodontists recognized a need for 3D cephalometrics. Craniofacial CBCT scanners were developed at the beginning of the 21st century in order to overcome limitations of conventional CT scanners. CBCT enabled us to analyse skeletal and soft-tissue structures of our patients in all three dimensions of space and as 3D volumes using the data from a single scan which exposes the patient to significantly less radiation then the conventional CT scanner. The aim of this doctoral dissertation was to analyse upper airway and facial soft-tissue changes of adolescent patients treated orthodontically with or without extractions, and adult patients treated by combined orthodontic-surgical treatment. The sample consisted of 107 patients treated at the Department of Orthodontics and the University Hospital of the Case Western Reserve University in Cleveland, OH, USA. All patients were scannen before and after treatment, as a part of the standard diagnostic and therapeutic procedure, using an adjusted Hitachi CB MercuRay scanner (2 mA, 120 kV, 12‖ FOV, F Mode). Depending on the type of treatment patients were divided into three groups. Cephalometric analysis, analysis of upper, or pharyngeal (PAS-Pharyngeal Airway Space) airways (Nasopharyngeal (NP) and Oropharyngeal (OP) Volumes and Area of Maximal Pharyngeal Constriction (AMPC)) and facial soft-tissue analysis (both in 2D and 3D) were preformed for all patients...

Trodimenzionalnost (3D) ljudskog tela proučavana je još od antičkog vremena. Početkom XX veka, gips je bio osnovno dijagnostičko sredstvo za prikazivanje dentofacijalne morfologije, pa je većina ortodonata koristila gipsane studijske modele za analizu denticije i alveolarnih nastavaka u sve tri ravni prostora. Neki ambiciozniji ortodonti, meĎu kojima i Calvin Case predlagali su pravljenje gipsanih modela lica, kako bi se zabeleţile karakteristike lica pre i posle terapije. Kefalometrija, koja je uvedena u ortopediju vilica sredinom dvadesetih godina prošlog veka, omogućila je opisivanje morfologije i rasta kraniofacijalnog skeleta, predviĎanje rasta, planiranje terapije i evaluaciju ishoda terapije. Ipak, potreba za trodimenzionalnom kefalometrijom prepoznata je još sredinom prošlog veka. Kraniofacijalni CBCT skeneri razvijeni su početkom XXI veka kako bi se prevazišla ograničenja konvencionalnih CT skenera. CBCT je omogućio ortodontima da analiziraju skeletne i mekotkivne strukture svojih pacijenata u sve tri dimenzije prostora i kao 3D strukture, i to pomoću samo jednog skena koji pacijenta izlaţe značajno manjoj dozi zračenja u odnosu na CT skener. Cilj ove doktorske disertacije bio je da se procene promene na nivou gornjih vazdušnih puteva i mekih tkiva lica adolescentnih pacijenata tretiranih ekstrakcionom i neekstrakcionom ortodontskom terapijom i odraslih pacijenata tretiranih kombinovanom ortodontsko-hirurškom terapijom. Uzorak se sastojao od 107 pacijenata, izdvojenih iz grupe od 141 pacijenta tretiranog na Stomatološkom fakultetu i u Univerzitetskoj bolnici Case Western Reserve Univerziteta, u Klivlendu, SAD. Svi pacijenti su snimljeni pre i posle terapije prilagoĎenim Hitachi CB MercuRay skenerom (2 mA, 120 kV, 12-inčno polje pregleda u F Modu) u okviru standardnog dijagnostičkog i terapeutskog postupka. U zavisnosti od vrste terapije, pacijenti su podeljeni u tri grupe. Za sve pacijente je uraĎena kefalometrijska analiza, merene su dimenzije gornjih vazdušnih puteva (zapremine nazofarinksa (NP) i orofarinksa (OP) i površina najuţeg dela farinksa (AMPC – Area of Maximal Pharyngeal Constriction) i dimenzije mekih tkiva lica, kako dvodimenzionalne, tako i trodimenzionalne...