Open bite treatment using clear aligners.

A 35-year-old female patient with dentoalveolar open bite of 4 mm, molar Class I malocclusion, centered midlines, moderate crowding, and labial inclination of the lower incisor was treated with clear aligners to reduce protrusion and close the anterior open bite. The result showed that clear aligners were an effective method with which to correct this malocclusion. The treatment was complete after 18 months. The patient was satisfied with her new appearance and function.

The effect of temperature on the mechanical behavior of nickel-titanium orthodontic initial archwires.

OBJECTIVES: To investigate and compare the characteristics of commonly used types of traditional and heat-activated initial archwires at different temperatures by plotting their load/deflection graphs and quantifying three parameters describing the discharge plateau phase. MATERIALS AND METHODS: Forty-eight archwires of cross-sectional diameters ranging from 0.010 inches to 0.016 inches were obtained from seven different manufacturers. A modified three-point wire-bending test was performed on three analogous samples of each type of archwire at 55°C and 5°C, simulating an inserted archwire that is subjected to cold or hot drinks during a meal. For each resulting load/deflection curve the plateau section was isolated and the mean value of each parameter for each type of wire was obtained. RESULTS: Permanent strain was exhibited by all wires tested at 55°C. Statistically significant differences were found between almost all wires for the three considered parameters when tested at 55°C and 5°C. Loads were greater at 55°C than at 5°C. Differences were also found between traditional and heat-activated archwires, the latter of which generated longer plateaus at 55°C, shorter plateaus at 5°C, and lighter mean forces at both temperatures. The increase in average force seen with increasing diameter tended to be rather stable at both temperatures. CONCLUSIONS: All nickel-titanium wires tested showed a significant change related to temperature in terms of behavior and force for both traditional and heat-activated wires. Stress under high temperatures can induce permanent strain, whereas the residual strain detected at low temperatures can be recovered from as temperature increases.

Assessment of lower lip changes following incisor displacement in 92 orthodontically-treated adults.

AIM: A retrospective assessment of the lower lip changes consequent to incisor displacement in correction of malocclusion in a sample of 92 post-adolescent subjects. METHODS: The study sample comprised two groups, subdivided according to the direction of incisor movement achieved during orthodontic treatment: the retraction group (Group 1), made up of 41 patients in which the maxillary incisor had been moved in a palatal direction (palatal tipping); and the protraction group (Group 2), composed of 51 patients who had undergone labial movement of the upper incisors (labial tipping). In order to evaluate the mean changes in lower lip position, and consequent alterations in the quality of the patients' profiles, between T1 (prior to orthodontic displacement of the incisors) and T2 (following treatment), the following parameters were measured on lateral head film X rays: variation in lower lip vermilion thickness (dLVT); variation in lower lip sulcus depth (dLLSD); variation in lower vermilion height (dLVH); variation in exposure of the upper and lower incisors in relation to the lower stomion (dIs-STOi and dIi-STOi, respectively); variation in upper and lower incisor tipping with respect to the palatal plane (d1/PP and dinf1/PP); and variation in lower facial height (dLFH). RESULTS: Assessment of the changes due to incisor translocation revealed significant differences between Group 1 and Group 2 in all lower lip soft tissue parameters, except for dLVT, dLVH and dIi-STOi. Furthermore, using multiple linear regression analysis to predict the behaviour of the dependent (cutaneous) lower lip variables, a good coefficient of determination (r-square) value was only obtained for the horizontal variation of the labrale inferius point (dxLi), found to be dependent on horizontal movement of the upper and lower incisors (dxIs and dxIi) and thickness of the lower vermilion (LVT). CONCLUSIONS: The results of this study highlight great variability among the patients studied, and suggest that the behaviour of the soft tissues (lower lip changes) following displacement of the upper and lower incisors is multifactorial and very difficult to predict.

Comparison of the anterior limit of the dentition in patients treated with self-ligating straight-wire, conventional straight-wire and standard edgewise appliances.

THE AIM OF THIS STUDY WAS TO IDENTIFY AND COMPARE ANY DIFFERENCES IN THE POSITION OF THE ANTERIOR LIMIT OF THE DENTITION PROVOKED BY THREE DIFFERENT TYPES OF ORTHODONTIC MECHANICS: traditional edgewise, straightwire and self-ligating. A sample of 54 patients (selected from a group of 289 patients) possessed a range of Little's Irregularity Index values for the upper and lower dental arches between a minimum of 6.5 and a maximum of 13.5 at T0, and corresponding final values no greater than 2 and hence of minimal irregularity. The 54 patients were subdivided into three groups according to the type of brackets used in their treatment: Group 1 was composed of 24 patients treated using the self-ligating technique, Group 2 of 15 patients treated using a conventional straight-wire technique (Roth) and Group 3 of 15 patients treated using the standard edgewise technique. Cephalometric tracings were performed on laterolateral teleradiography. Group 1 value was found to be nonsignificant, whereas significant labial inclination was noted in Groups 2 and 3 (P < 0.05). A significant labial inclination of the upper incisors was also evidenced in all three sample groups.

Anterior dental alignment and smile: perception and sensations in a sample of 8- to 10-year-old children and their parents.

AIM: To describe the perception and sensations that dental alignment and smile determine in a sample of 180 children aged between 8 and 10 years, to assess whether there is a general trend in the classification of smiles, and to understand the influence of background attractiveness and sexual traits on the judgment of smile in the sample of children and 150 parents. METHODS: We employed visual media showing a smile in four different arrangements (ideal incisal occlusion [N], median diastema [D], incisal crowding [A], and protruding incisors [P), in both a dynamic and static way, with and without background attractiveness. RESULTS: Trends were found among responses to the four classes of videos and photographs: The boy's smile gained a higher score than the girl's smile. In both the boy and girl presentations, there was an important preference to the following sequence of smiles: N, D, A, and P. Furthermore, the girl photographs showed no relevant difference between A and D. CONCLUSION: This study showed that there are no different perceptions and sensations due to the variation of dental alignment. There is a general trend in the classification of smiles according to dental alignment. Background attractiveness and sexual traits influenced the judgment of smile.

Short-term chemical and physical changes in invisalign appliances.

OBJECTIVE: To investigate the short-term optical, chemical and morphological changes in Invisalign appliances. METHODS: One 'as-received' Invisalign aligner, one 'as-received' Invisalign aligner immersed in artificial saliva for 14 days and 10 Invisalign aligners worn by 10 randomly selected patients for 14 days were used. Fourier'transform infra-red microspectroscopy was used to characterise any molecular changes on the surfaces of the appliances, spectrophotometry was used to evaluate any changes in colour and transparency, scanning electron microscopy and energy dispersive X-ray microanalysis were used to examine the surface morphology and elemental composition of deposits on the surfaces of the aligners and gas chromatography-mass spectrometry was used to identify substances released from the aligners into the artificial saliva. RESULTS: Aligners worn for 14 days had microcracks, abraded and delaminated areas, localised calcified biofilm deposits and loss of transparency. Monomers and/or by-products were not released from the aligner suspended in artificial saliva for 14 days, which suggests that the material is chemically stable. CONCLUSIONS: Further studies are required to evaluate how intra-oral conditions may influence the optical properties and chemical stability of the aligners.