5 research outputs found
Severe transposition, ectopic eruption, and orthodontic alignment: a long-term appraisal.
A female patient, 13 years of age, with severe localized crowding and transposition of the right maxillary canine and ectopic eruptions of premolars and incisors, desired treatment. The treatment plan consisted of extraction of 1 displaced premolar and correction of the transposition and crowding by orthodontic means. Crowding correction using the Begg appliance was the technique employed. The case report includes a 12-year posttreatment review, and demonstrates that, with careful planning and close monitoring, it is possible to correct complex transposition problems by orthodontic methods.link_to_subscribed_fulltex
The reproducibility of cephalometric landmarks: an experimental study on skulls.
Few previous cephalometric studies have used dry skulls in order to eliminate the effects of the facial soft tissues. The aim of this study were to quantify the intra-examiner reproducibility of the commonly used cephalometric landmarks, angles and distances, using dry skulls and to compare these errors with previous error data obtained from normal cephalograms of living patients. Thirty skulls were mounted in a purpose-designed holder and repeat cephalograms of each skull were recorded and digitised. All measurements were made relative to an X-Y coordinate reference grid. Scattergrams were produced to show the characteristic distribution of the intra-examiner reproducibility errors for the landmarks, and the reproducibility of the angles and distances were tabulated. This data was compared with a related study that included the soft tissue profile. The standard deviations of the skeletal and dental angles and distances were greater in the presence of the soft tissues. These differences were up to four times larger for measurements including the location of Nasion (e.g. SNA, SNB and SNPg), which was the landmark location most affected by the presence of soft tissues, and for the distance: Incisal tip of Lower Incisor to Pogonion. Anterior Nasal Spine, in the horizontal plane, was also greatly affected by the presence of the soft tissues. By using dry skulls, the errors observed in this study may serve as standards for the rational interpretation of clinical cephalometric values.link_to_subscribed_fulltex