[Genetics and tooth eruption disorders: a future exploration]

status: publishe

Long-term stability of the leveling of the curve of Spee.

Item does not contain fulltextThe aim of the study was to investigate whether the orthodontic leveling of the curve of Spee is a treatment procedure with a stable result on a long-term basis. Measurements were made on the plaster casts of 149 orthodontically treated patients (57 males and 92 females). The mean age before treatment was 12.8 years (range, 8-25 years). Study casts were taken before treatment (T1), at the completion of orthodontic therapy (T2), and 6.7 years (mean) posttreatment (T3). Inclusion criteria were no extractions, all Angle classifications except Class III malocclusions, and all permanent teeth fully erupted except second and third molars. The curve of Spee and the irregularity index were measured on standardized digital photographs of the casts. Overjet and overbite were assessed with a ruler. Changes in the curve of Spee were correlated with changes in irregularity index, overjet, and overbite from T1 to T3. The following results were noted: (1) leveling of the curve of Spee is a relatively stable treatment procedure compared with a return of incisor crowding and deepening of the bite; (2) neither the initial depth of the curve of Spee nor the initial irregularity index is an indicator for the amount of relapse; (3) the amount of leveling is not correlated with the relapse of the 4 tested parameters (curve of Spee, irregularity index, overjet, and overbite); and (4) there is a mild correlation between the relapse of the curve of Spee and the relapse of the irregularity index, overjet, and overbite. According to the results of the study, leveling the curve of Spee during orthodontic treatment seems to be very stable on a long-term basis; it was weakly correlated with the other variables tested

Infant orthopedics and facial appearance: A randomized clinical trial (Dutchcleft)

OBJECTIVE: To study the effect of infant orthopedics on facial appearance. DESIGN: Prospective two-arm randomized controlled trial in parallel with three participating academic cleft palate centers. Treatment allocation was concealed and performed by means of a computerized balanced allocation method. SETTING: Cleft Palate Centers of Amsterdam, Nijmegen, and Rotterdam, the Netherlands. PATIENTS: Infants with complete unilateral cleft lip and palate, no other malformations. Interventions: One group (IO(+)) wore passive maxillary plates during the first year, the other group (IO(-)) did not. MAIN OUTCOME MEASURE(S): Two metrical response modalities were used (i.e., visual analog scales and reference scores) to score facial appearance. Full face and cropped photographs were compared with reference photographs and were judged. The photographs were judged by 45 judges, 24 laypeople, and 21 professionals. Transformation of the scores into z scores was applied to compare and to pool both response modalities. The validity of each individual judge was evaluated, as was the reliability of the scales. Differences between the treatment groups were evaluated by means of t tests. RESULTS: Photographs were available of 41 subjects, 21 with and 20 without infant orthopedics. No significant differences were found between groups. Mean z-score values for the full-face photographs were: group IO(+) = 0.10 (SD = 0.73) and group IO(-) = -0.03 (SD = 0.48); for the cropped photographs were: group IO(+) = 0.12 (SD = 0.71) and group IO(-) = -0.06 (SD = 0.55). CONCLUSIONS: Infant orthopedics have no effect on facial appearance

Craniofacial morphology in unilateral hemifacial microsomia

Hemifacial microsomia (HFM) is a complex three-dimensional congenital condition that is characterized by mandibular hypoplasia and unilateral or bilateral microtia; although, other facial structures may be affected. Little is known about craniofacial growth and morphology in patients with HFM; therefore, we examined 75 HFM patients by means of a cephalometric analysis in a longitudinal study on serial lateral cephalograms. We hypothesized that the growth of several facial structures on both sides of HFM patients would be different compared to Dutch controls. We determined patients with HEM had more retruded mandibles and maxillae and a more vertical morphology compared to the reference population. In addition, there was a more retruded and vertical pattern on the affected side compared to the unaffected side and in patients with a severe condition compared to those with a mild condition. 'Mild' HFM patients were more similar to the Dutch reference population than the 'severe' HFM patients. Individual HFM growth curves showed very high inter-variability, further strengthening the need for individualized treatment plans that consider all three dimensions and the severity of the condition. (C) 2012 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved

Linear Mandibular Measurements: Comparison Between Orthopantomograms and Lateral Cephalograms

Objective; To investigate the reliability of length measurements of the mandible by comparing orthopantomograms (OPTs) with lateral cephalograms. Design: Observational study. Setting: OPTs and lateral cephalograms were taken of 20 human dry skulls. Four orthodontists and four maxillofacial surgeons located landmarks on all radiographs using a computer program for cephalometric measurements. Intraobserver and Interobserver variability in locating landmarks was assessed, as well as positioning of the skulls prior to radiography between the x-ray assistants. Magnification differences between the left and right side of the mandible on the OPT were determined for five skulls. Kappa statistics were used to calculate the Intraclass correlation coefficient for intraobserver and interobserver differences. An F test was used to assess differences between methods and between type of observer. Results: No significant differences were found in the magnification factor of the left and right side of the mandible. Compared with a lateral cephalogram, the OPT had comparable reliability in measuring mandibular distances condylion-gonion, gonion-menton, and condylion-menton. No significant differences were observed between the x-ray assistants in taking the OPTs and lateral cephalograms or In repositioning the skulls. Significant differences were found between orthodontists and maxillofacial surgeons for landmark measurements. Conclusion: An OPT is as reliable as a lateral cephalogram for linear measurements of the mandible (condylion-gonion, gonion-menton, and condylion-menton)

Stability of upper incisor inclination changes in Class II division 2 patients

A

Relaxin stimulates MMP-2 and alpha-smooth muscle actin expression by human periodontal ligament cells

The main cells in the periodontal ligament (PDL) are the fibroblasts, which play an important role in periodontal remodelling. Matrix metalloproteinases (MMPs) are largely responsible for the degradation of extracellular matrix proteins in the PDL. Previous studies have indicated that MMP production can be stimulated by the hormone relaxin. This hormone facilitates delivery by softening the connective tissues of the reproductive tract, and it prepares the mammary gland for lactation. Periodontal remodelling takes place during orthodontic tooth movement, which might be enhanced by relaxin. Therefore, we investigated the effects of relaxin on gelatinase expression of human PDL cells. Cultures of human PDL cells were incubated with relaxin. Gelatinase (MMP-2 and -9) expression, alpha-smooth muscle actin expression (alpha-SMA), total MMP activity and DNA content were measured. Both proMMP-2 and active MMP-2 was identified in the cultures. There was a clear trend showing a dose-dependent increase of MMP-2 production, which was significant at 250 ng/ml. Total MMP activity was not affected. A stimulation of alpha-SMA expression was found at 50 ng/ml. The results indicate that relaxin activates human PDL cells by the stimulation of MMP-2 and alpha-smooth muscle actin