ABSTRACT
Timing is an important factor in orthodontic treatment planning. Skeletal age is a standard indicator for determining optimum time for treatment. On the other hand, in clinic the phases of the dentition [deciduous, early and late mixed, permanent] have often been used for treatment timing, investigations of the different outcomes of treatment protocols at earlier vs later stages of development. Considering the importance of this issue and to evaluate it in the Iranian adolescents, the purpose of this study was to evaluate the relation between clinical phases of dental eruption and the skeletal maturity stages by cervical vertebrae method [CVM]. Panoramic radiographs and lateral cephalograms of 100 boys and 100 girls were used. For determination of the Phases of dentition, Vander Linden method and for the skeletal maturity, CVM were used. The relationship between the skeletal maturity [stages in CVM] and the phases of the dentition was evaluated statistically by means of indicators of diagnostic tests and spearman's rho analysis. Spearman's rho analysis indicated a relatively strong correlation of 0.775 [P<0.001]; The early mixed dentition phase was a valid indicator of prepubertal stage [CS1], but the late mixed and early permanent dentitions were not valid indicators for the diagnosis of the onset of the pubertal growth spurt [CS3]. In comparison with a reliable indicator of skeletal maturity [CVM], the dentition phases perform poorly in the detection of the onset of the pubertal spurt in skeletal growth.
ABSTRACT
OBJECTIVE: The purpose of this study was to evaluate the surface roughness (SR) of 2 types of orthodontic archwires made by 4 different manufacturers. METHODS: This in vitro experimental study was conducted on 35 specimens of 7 different orthodontic archwires, namely, 1 nickel-titanium (NiTi) archwire each from the manufacturers American Orthodontics, OrthoTechnology, All-Star Orthodontics, and Smart Technology, and 1 stainless steel (SS) archwire each from the manufacturers American Orthodontics, OrthoTechnology, and All-Star Orthodontics. After analyzing the composition of each wire by energy-dispersive X-ray analysis, the SR of each wire was determined by scanning electron microscopy (SEM) and surface profilometry. Data were analyzed using the Kruskal-Wallis and Mann-Whitney U tests (alpha < 0.05). RESULTS: The average SR of NiTi wires manufactured by Smart Technology, American Orthodontics, OrthoTechnology, and All-Star Orthodontics were 1,289 +/- 915 Adegrees, 1,378 +/- 372 Adegrees, 2,444 +/- 369 Adegrees, and 5,242 +/- 2,832 Adegrees, respectively. The average SR of SS wires manufactured by All-Star Orthodontics, OrthoTechnology, and American Orthodontics were 710 +/- 210 Adegrees, 1,831 +/- 1,156 Adegrees, and 4,018 +/- 2,214 Adegrees, respectively. Similar to the results of profilometry, the SEM images showed more defects and cracks on the SS wire made by American Orthodontics and the NiTi wire made by All-Star Orthodontics than others. CONCLUSIONS: The NiTi wire manufactured by All-Star Orthodontics and the SS wire made by American Orthodontics were the roughest wires.
Subject(s)
Microscopy, Electron, Scanning , Orthodontics , Stainless SteelABSTRACT
Class III malocclusions are considered as one of the most complex orthodontic problems to diagnose and treat. Numerous studies have been conducted to determine the morphologic characteristics of craniofacial complex in patients with this malocclusion. The aim of this study was to determine the dentofacial characteristics of Class III malocclusion in Mashhadian adults. This cross-sectional descriptive study consisted of 114 cephalograms including 57 individuals with Class III malocclusion [28 males and 29 females with mean age of 19.28 years] as the case group, and 57 adults with uncrowded Class I occlusion [28 males and 29 females with mean age of 17.2 years] as the control group. Cephalometric evaluation was performed by measuring nine angular and nine linear measurements and the dentofacial characteristics of two groups were compared by Student's t-test. SNA angle, the distance from A point to Nasion perpendicular and the maxillary effective length was significantly lower in Class III group, while SNB and SN-Pog angles were significantly higher compared to control group. Mandibular effective length did not differ in two groups. Maxillary incisor protrusion and mandibular incisor retrusion in Class III subjects was also observed. From the vertical aspect, only mandibular plane angle showed an increase in Class III group [P < 0.05]. Maxillary deficiency, mandibular prognathism, maxillary incisors protrusion and mandibular incisors retrusion are present in individuals with Class III malocclusion, but mandibular effective length does not differ significantly from Class I patients